The present application is a divisional application of an invention patent application having an application number of 201410333238.6, an application date of 2004, 26/7, and an invention name of "exposure apparatus, device manufacturing method". The application No. 201410333238.6 is a divisional application of an invention patent application having an application No. 200480021856.1, an application date of 2004, 26/7, and an invention title of "exposure apparatus, device manufacturing method, and method for controlling exposure apparatus".
Detailed Description
An embodiment of the exposure apparatus of the present invention will be described below with reference to the drawings, but the present invention is not limited thereto.
Fig. 1 is a schematic configuration diagram showing embodiment 1 of an exposure apparatus of the present invention. In fig. 1, the exposure apparatus EX includes a mask stage MST for supporting the mask M, a substrate stage PST for supporting the substrate P, an illumination optical system IL for illuminating the mask M supported by the mask stage MST with the exposure light EL, a projection optical system PL for projecting and exposing a pattern of the mask M illuminated by the exposure light EL onto the substrate P supported by the substrate stage PST, and a control apparatus CONT for collectively controlling the operation of the entire exposure apparatus EX. An alarm device K for giving an alarm when an abnormality occurs with respect to the exposure processing is connected to the control device CONT. The exposure apparatus EX further includes a main column 3 that supports the mask stage MST and the projection optical system PL. The main column 3 is provided to a base plate 4 horizontally placed on the floor surface. An upper step portion 3A and a lower step portion 3B are formed on the main column 3 so as to protrude inward. As shown in fig. 23, the control device is connected to various components constituting the exposure apparatus and related devices outside the exposure apparatus, and the control of the control device will be described later.
In order to substantially shorten the exposure wavelength, improve the resolution, and substantially increase the depth of focus, the exposure apparatus EX of the present embodiment is a liquid immersion exposure apparatus to which a liquid immersion method is applied, and includes a liquid supply mechanism 10 that supplies the liquid 1 onto the substrate P and a liquid recovery mechanism 20 that recovers the liquid 1 on the substrate P. While the exposure apparatus EX transfers at least the mask M onto the substrate P, the liquid immersion area AR2 is formed in a part of the substrate P including the projection area AR1 of the projection optical system PL by the liquid 1 supplied from the liquid supply mechanism 10. Specifically, the liquid 1 is filled between the optical element 2 at the tip end portion (terminal end portion) of the projection optical system PL of the exposure apparatus EX and the surface of the substrate P, and the substrate P is exposed by projecting the pattern image of the mask M onto the substrate P through the liquid 1 and the projection optical system PL between the projection optical system PL and the substrate P.
In the present embodiment, a case will be described as an example where a scanning type exposure apparatus (so-called step-and-scan exposure apparatus) that exposes a pattern formed on a mask M to a substrate P while synchronously moving the mask M and the substrate P in directions different from each other (opposite directions) in a scanning direction is used as the exposure apparatus EX. In the following description, a direction coincident with the optical axis AX of the projection optical system PL is defined as a Z-axis direction, a synchronous movement direction (scanning direction) of the mask M and the substrate P in a plane perpendicular to the Z-axis is defined as an X-axis direction, and a direction (non-scanning direction) perpendicular to the Z-axis direction and the X-axis direction is defined as a Y-axis direction. Further, the rotation (tilt) directions around the X, Y, and Z axes are referred to as θ X, θ Y, and θ Z directions, respectively. The term "substrate" as used herein includes a plate obtained by coating a photoresist as a photosensitive material on a semiconductor wafer, and the term "mask" includes a reticle on which a device pattern to be reduced and projected on the substrate is formed.
The illumination optical system IL is supported by a support column 5 fixed to the upper portion of the main column 3. The illumination optical system IL illuminates a mask M supported on a mask stage MST with exposure light EL, and includes an exposure light source, an optical integrator for uniformizing illuminance of a light flux emitted from the exposure light source, a condenser lens for condensing the exposure light EL from the optical integrator, a relay lens system, a variable field stop for setting an illumination region of the exposure light EL on the mask M to a slit shape, and the like. A predetermined illumination region on the mask M is illuminated with exposure light EL having a uniform illuminance distribution by IL. As the exposure light EL emitted from the illumination optical system IL, for example, deep ultraviolet light (DUV light) such as glow light (g-line, h-line, i-line) in the ultraviolet region emitted from a mercury lamp and KrF excimer laser light (wavelength 248nm), ArF excimer laser light (wavelength 193nm) and F excimer laser light (wavelength 193nm) can be used2Vacuum ultraviolet light (VUV light) such as laser light (157 nm). In the present embodiment, an ArF excimer laser is used.
In the present embodiment, pure water is used as the liquid 1. Pure water is not only transmitted by ArF excimer laser light, but also transmitted by deep ultraviolet light (DUV light) such as glow (g-line, h-line, i-line) in the ultraviolet region emitted from a mercury lamp and KrF excimer laser light (wavelength 248 nm).
The mask stage MST supports the mask M and has an opening portion 34A in a central portion thereof through which a pattern image of the mask M passes. The mask base plate 31 is supported by the vibration preventing unit 6 at the upper step portion 3A of the main column 3. An opening 34B for passing the pattern image of the mask M is also formed in the center of the mask blank 31. A plurality of gas bearings (air bearings) 32 as non-contact bearings are provided below the mask stage MST. The mask stage MST is supported on an upper surface (guide surface) 31A of the mask base plate 31 in a non-contact manner by a gas bearing 32, and is moved in 2 dimensions and slightly rotated in the θ Z direction in an XY plane which is a plane perpendicular to the optical axis AX of the projection optical system PL by a mask stage driving mechanism such as a linear motor. A movable mirror 35 is provided on the mask stage MST so as to be movable together with the mask stage MST relative to the projection optical system PL. Further, a laser interferometer 36 is provided at a position facing the moving mirror 35. The position of the mask M on the mask stage MST in the 2-dimensional direction and the rotation angle in the θ Z direction (in some cases, the rotation angles in the θ X and θ Y directions are included) are measured in real time by the laser interferometer 36, and the measurement results are output to the control unit CONT. The control device CONT drives the mask stage drive mechanism based on the detection result of the laser interferometer 36, thereby controlling the position of the mask M supported on the mask stage MST.
The projection optical system PL is for projecting the pattern of the mask M onto the substrate P at a predetermined projection magnification β, and is composed of a plurality of optical elements (lenses) including an optical element (lens) 2 provided at a front end portion on the substrate P side, and these optical elements are supported by a lens barrel PK. In the present embodiment, the projection optical system PL is a reduction system having a projection magnification β of, for example, 1/4 or 1/5. The projection optical system PL may be an equal magnification system or an enlargement system. A flange portion FLG is provided at an outer peripheral portion of the lens barrel PK. In addition, a barrel fixing plate 8 is supported by a vibration preventing unit 7 at the lower step portion 3B of the main column 3. The projection optical system PL is supported by the barrel fixing plate 8 by joining the flange portion FLG of the projection optical system PL to the barrel fixing plate 8.
The optical element 2 at the tip of the projection optical system PL of the present embodiment is detachably (replaceably) provided to the lens barrel PK. The liquid 1 in the liquid immersion area AR2 contacts the optical element 2. The optical element 2 is formed of fluorite. Since fluorite has high affinity for water, the liquid 1 can be brought into close contact with substantially the entire liquid contact surface 2a of the optical element 2. That is, in the present embodiment, since the liquid (water) 1 having high affinity with the liquid contact surface 2a of the optical element 2 is supplied, the liquid contact surface 2a of the optical element 2 has high close contact with the liquid 1, and the optical path between the optical element 2 and the substrate P can be reliably filled with the liquid 1. The optical element 2 may be quartz having a high affinity for water. Further, the liquid contact surface 2a of the optical element 2 may be subjected to hydrophilization (lyophilic) treatment to further improve the affinity with the liquid 1.
The plate member 2P is provided so as to surround the optical element 2. The surface (i.e., the lower surface) of the plate member 2P facing the substrate P is a flat surface. The lower surface (liquid contact surface) 2a of the optical element 2 is also a flat surface, and the lower surface of the plate member 2P is substantially flush with the lower surface of the optical element 2. Thus, the liquid immersion area AR2 can be formed well in a wide range. Further, a surface treatment (lyophilic treatment) is performed on the lower surface of the plate member 2P in the same manner as the optical element 2.
The substrate stage (movable member) PST is movably provided so as to be capable of holding the substrate P by adsorption by the substrate tray (substrate holding member) PH, and a gas bearing (air bearing) 42 as a plurality of non-contact bearings is provided below the substrate stage (movable member). The base plate 4 supports the base plate 41 via the vibration isolation unit 9. The air bearing 42 has a discharge port 42B and an air inlet 42A, the discharge port 42B discharges air (air) against the upper surface (guide surface) 41A of the substrate base plate 41, the air inlet 42A sucks the air between the lower surface (bearing surface) of the substrate stage PST and the guide surface 41A, and a constant gap is maintained between the lower surface of the substrate stage PST and the guide surface 41A by the balance between the repulsive force generated by the discharge of the air from the discharge port 42B and the suction force generated by the air inlet 42A. That is, the substrate stage PST is supported by the air bearing 42 in a non-contact manner with respect to the upper surface (guide surface) 41A of the substrate base plate (base member) 41, and is movable in 2 dimensions and slightly rotatable in the θ Z direction in the XY plane, which is a plane perpendicular to the optical axis AX of the projection optical system PL, by a substrate stage driving mechanism such as a linear motor. The substrate tray PH is also movably disposed in the Z-axis direction, the θ X direction, and the θ Y direction. The substrate table driving mechanism is controlled by the controller CONT. That is, the substrate tray PH controls the focal position (Z position) and the tilt angle of the substrate P, and positions the substrate P in the X-axis direction and the Y-axis direction by aligning the surface of the substrate P with the image plane of the projection optical system PL in the auto focus method and the auto leveling method.
A movable mirror 45 is provided on the substrate stage PST (substrate tray PH) so as to be movable together with the substrate stage PST with respect to the projection optical system PL. Further, a laser interferometer 46 is provided at a position facing the moving mirror 45. The position and the rotation angle of the substrate P on the substrate stage PST in the 2-dimensional direction are measured in real time by the laser interferometer 46, and the measurement results are output to the control unit CONT. The control device CONT drives a substrate stage driving mechanism including a linear motor based on the measurement result of the laser interferometer 46, thereby positioning the substrate P supported on the substrate stage PST.
An auxiliary plate 43 (see fig. 2) is provided on the substrate stage PST (substrate tray PH) so as to surround the substrate P. The auxiliary plate 43 has a flat surface having substantially the same height as the surface of the substrate P held on the substrate tray PH. When the edge region of the substrate P is exposed, the auxiliary plate 43 may hold the liquid 1 under the projection optical system PL.
Further, a recovery port (suction port) 61 of a recovery device 60 for recovering the liquid 1 flowing out to the outside of the substrate P is provided outside the auxiliary plate 43 in the substrate tray PH. The recovery port 61 is an annular groove formed to surround the auxiliary plate 43, and a liquid absorbing member 62 made of a sponge-like member, a porous body, or the like is disposed inside the recovery port.
Fig. 2 is a schematic perspective view showing the substrate stage PST and a substrate stage driving mechanism that drives the substrate stage PST. In fig. 2, the substrate stage PST is supported by the X guide table 44 so as to be movable in the X axis direction. The substrate stage PST is guided by the X guide table 44 and moved in the X-axis direction by a predetermined stroke by the X linear motor 47. The X linear motor 47 includes a stator 47A extending in the X axis direction on the X guide table 44 and a mover 47B provided corresponding to the stator 47A and fixed to the substrate table PST. The movable element 47B is driven relative to the stator 47A to move the substrate stage PST in the X-axis direction. Here, the substrate stage PST is supported in a noncontact manner by a magnetic guide mechanism including a magnet and an actuator that maintain a predetermined amount of gap in the Z-axis direction with respect to the X guide table 44. The substrate stage PST is moved in the X-axis direction by the X linear motor 47 in a state of being supported in a non-contact manner on the X guide table 44.
The X guide table 44 is provided with 1 pair of Y linear motors 48 at both ends in the longitudinal direction, and the Y linear motors 48 can move the X guide table 44 in the Y axis direction together with the substrate table PST. The Y linear motor 48 includes a mover 48B provided at each end of the X guide table 44 in the longitudinal direction and a stator 48A provided corresponding to the mover 48B. The movable element 48B is driven relative to the stator 48A, thereby moving the X guide table 44 in the Y axis direction together with the substrate table PST. Further, by adjusting the drive of the Y linear motor 48, the X guide table 44 can also be rotated in the θ Z direction. Therefore, the substrate stage PST can be moved substantially integrally with the X guide stage 44 in the Y axis direction and the θ Z direction by the Y linear motor 48.
Guide portions 49 are provided on both sides of the substrate base plate 41 in the X-axis direction, and the guide portions 49 are formed in an L-shape in front view to guide the movement of the X guide table 44 in the Y-axis direction. The guide portion 49 is supported on the base plate 4 (fig. 1). In the present embodiment, the stator 48A of the Y linear motor 48 is provided in the flat portion 49B of the guide portion 49. On the other hand, concave guided members 50 are provided at both longitudinal end portions of the lower surface of the X guide table 44. The guide portion 49 is engaged with the guided member 50, and an upper face (guide face) 49A of the guide portion 49 is disposed opposite to an inner face of the guided member 50. A gas bearing (air bearing) 51 as a non-contact bearing is provided on the guide surface 49A of the guide portion 49, and the X guide table 44 is supported in a non-contact manner with respect to the guide surface 49A.
In addition, a gas bearing (air bearing) 52 as a non-contact bearing is provided between the stator 48A of the Y linear motor 48 and the flat portion 49B of the guide portion 49, and the stator 48A is supported by the air bearing 52 in non-contact with respect to the flat portion 49B of the guide portion 49. For this reason, according to the law of conservation of momentum, the stator 48A is moved in the-Y direction (+ Y direction) in response to the + Y direction (-Y) movement of the X guide table 44 and the substrate table PST. The reaction force of the movement of the X guide table 44 and the substrate table PST is cancelled by the movement of the stator 48A, and the change in the position of the center of gravity can be prevented. That is, the stator 48A has a function as a so-called balance mass.
Fig. 3 is an enlarged view showing the vicinity of the tip of the liquid supply mechanism 10, the liquid recovery mechanism 20, and the projection optical system PL. The liquid supply mechanism 10 is for supplying the liquid 1 between the projection optical system PL and the substrate P, and has a liquid supply portion 11 capable of sending out the liquid 1, and a supply nozzle 14 connected to the liquid supply portion 11 through a supply tube 15 for supplying the liquid 1 sent out from the liquid supply portion 11 onto the substrate P. The supply nozzle 14 is disposed close to the surface of the substrate P. The liquid supply section 11 has a tank for storing the liquid 1, a pressure pump, and the like, and supplies the liquid 1 onto the substrate P through a supply tube 15 and a supply nozzle 14. The liquid supply operation of the liquid supply portion 11 is controlled by a control device CONT which can control the amount of liquid supplied per unit time on the substrate P by the liquid supply portion 11.
In the middle of the supply pipe 15, a flow meter 12 that measures the amount of the liquid 1 supplied from the liquid supply portion 11 onto the substrate P (liquid supply amount per unit time) is provided. The flow meter 12 constantly monitors the amount of the liquid 1 supplied onto the substrate P, and outputs the measurement result to the control device CONT. Further, a valve 13 for opening and closing a flow path of the supply pipe 15 is provided between the flow meter 12 and the supply nozzle 14 in the supply pipe 15. The opening and closing operation of the valve 13 is controlled by the control device CONT. The valve 13 of the present embodiment is of a normally closed type that mechanically closes the flow path of the supply tube 15 when the drive source (power supply) of the exposure apparatus EX (control apparatus CONT) is stopped by, for example, a power failure.
The liquid recovery mechanism 20 is for recovering the liquid 1 on the substrate P supplied by the liquid supply mechanism 10, and has a recovery nozzle (suction port) 21 disposed close to the surface of the substrate P and a vacuum system (suction system) 25 connected to the recovery nozzle 21 through a recovery tube 24. The vacuum system 25 includes a vacuum pump, and its operation is controlled by the control device CONT. The liquid 1 on the substrate P is recovered by the recovery nozzle 21 together with the gas (air) around the liquid by driving the vacuum system 25. As the vacuum system 25, a vacuum system of a plant in which the exposure apparatus EX is disposed may be used without providing a vacuum pump in the exposure apparatus.
A gas-liquid separator 22 for separating the liquid 1 and the gas sucked from the recovery nozzle 21 is provided in the middle of the recovery pipe 24. Here, as described above, the gas around the liquid on the substrate P is collected from the recovery nozzle 21 together with the liquid. The gas-liquid separator 22 separates the liquid 1 and the gas recovered from the recovery nozzle 21. As the gas-liquid separator 22, for example, a gravity separation type device, a centrifugal separation type device, or the like can be used; the gravity separation type device separates liquid and gas by dropping the liquid through the hole part under the action of gravity; this centrifugal separation type apparatus separates the recovered liquid and gas by using centrifugal force. The vacuum system 25 sucks the gas separated by the gas-liquid separator 22.
A dryer 23 for drying the gas separated by the gas-liquid separator 22 is provided between the vacuum system 25 and the gas-liquid separator 22 in the recovery pipe 24. Even if a liquid component is mixed in the gas separated by the gas-liquid separator 22, the gas is dried by the dryer 23, and the dried gas is caused to flow into the vacuum system 25, whereby it is possible to prevent the occurrence of problems such as failure of the vacuum system 25 due to the inflow of the liquid component. As the dryer 23, there can be used a cooler-type device for removing a liquid component by cooling a gas (gas mixed with a liquid component) supplied from the gas-liquid separator 22 to a dew point of the liquid or below, or a heater-type device for removing a liquid component by heating to a boiling point of the liquid or above.
On the other hand, the liquid 1 separated by the gas-liquid separator 22 is recovered to a liquid recovery section 28 through a2 nd recovery pipe 26. The liquid recovery section 28 includes a tank or the like for storing the recovered liquid 1. The liquid 1 recovered in the liquid recovery section 28 is, for example, discarded or cleaned and then returned to the liquid supply section 11 for reuse. Further, a flow meter 27 for measuring the amount of the liquid 1 recovered (the amount of the liquid recovered per unit time) is provided in the middle of the 2 nd recovery pipe 26 between the gas-liquid separator 22 and the liquid recovery portion 28. The flow meter 27 constantly monitors the amount of the liquid 1 collected from the substrate P and outputs the measurement result to the control unit CONT. As described above, the liquid 1 on the substrate P and the gas around the liquid are recovered from the recovery nozzle 21, but the liquid 1 and the gas are separated in the gas-liquid separator 22, and only the liquid component is sent to the flow meter 27, so that the flow meter 27 can accurately measure the amount of the liquid 1 recovered from the substrate P.
The exposure apparatus EX further includes a focus (focus) detection system 56 for detecting the position of the surface of the substrate P supported on the substrate stage PST. The focus detection system 56 has a light projecting portion 56A for projecting the detection beam onto the substrate P from obliquely above through the liquid 1 and a light receiving portion 56B for receiving the reflected light of the detection beam reflected by the substrate P. The light reception result of the focus detection system 56 (light receiving portion 56B) is output to the control device CONT. The control unit CONT detects the position information of the surface of the substrate P in the Z-axis direction based on the detection result of the focus detection system 56. Further, by projecting a plurality of detection beams from the light projecting portion 56A, tilt information in the θ X and θ Y directions of the substrate P can be detected.
The focus detection system 56 may detect surface position information of an object arranged on the image plane side of the projection optical system PL, not limited to the substrate P. Further, the focus detection system 56 detects the surface position information of the object (substrate P) by the liquid 1, but a focus detection system that detects the surface position information of the object (substrate P) without passing the liquid 1 may be employed outside the liquid immersion area AR 2.
As shown in a partial sectional view of fig. 1, the liquid supply mechanism 10 and the liquid recovery mechanism 20 are supported separately from the barrel fixing plate 8. Thus, the vibrations generated by the liquid supply mechanism 10 and the liquid recovery mechanism 20 are not transmitted to the projection optical system PL through the barrel fixing plate 8.
Fig. 4 is a plan view showing a positional relationship between the liquid supply mechanism 10 and the liquid recovery mechanism 20 and the projection area AR1 of the projection optical system PL. The projection area AR1 of the projection optical system PL is a rectangle (slit shape) elongated in the Y-axis direction, and 3 supply nozzles 14A to 14C are arranged on the + X side and 2 recovery nozzles 21A and 21B are arranged on the-X side with the projection area AR1 interposed therebetween in the X-axis direction. The supply nozzles 14A to 14C are connected to the liquid supply portion 11 through a supply pipe 15, and the recovery nozzles 21A, 21B are connected to a vacuum system 25 through a recovery pipe 24. The supply nozzles 14A 'to 14C' and the recovery nozzles 21A 'and 21B' are arranged at positions where the supply pins 14A to 14C and the recovery nozzles 21A and 21B are turned substantially 180 °. The supply nozzles 14A to 14C and the recovery nozzles 21A ', 21B' are alternately arranged in the Y-axis direction, the supply nozzles 14A 'to 14C' and the recovery nozzles 21A, 21B are alternately arranged in the Y-axis direction, the supply nozzles 14A 'to 14C' are connected to the liquid supply portion 11 through the supply tube 15 ', and the recovery nozzles 21A', 21B 'are connected to the vacuum system 25 through the recovery tube 24'. In the middle of the supply pipe 15 ', a flow meter 12 ' and a valve 13 ' are provided, as in the case of the supply pipe 15. Further, a gas-liquid separator 22 ' and a dryer 23 ' are provided in the middle of the recovery pipe 24 ', as in the recovery pipe 24.
Fig. 5 is a view showing a recovery device 60 for recovering the liquid 1 flowing out to the outside of the substrate P. In fig. 5, the recovery device 60 includes a recovery port (suction port) 61 formed on the substrate tray PH so as to surround the auxiliary plate 43, and a liquid absorbing member 62 disposed in the recovery port 61 and made of a porous material such as a sponge member or porous ceramic. The liquid absorbing member 62 is a ring-shaped member having a predetermined width, and can hold the liquid 1 at a predetermined amount. A flow path 63 communicating with the recovery port 61 is formed in the substrate tray PH, and the bottom of the liquid absorbing member 62 disposed in the recovery port 61 is in contact with the flow path 63. Further, a plurality of liquid recovery holes 64 are provided between the substrate P on the substrate tray PH and the auxiliary plate 43. These liquid recovery holes 64 are also connected to the flow path 63.
A plurality of projections 65 for supporting the back surface of the substrate P are provided on the upper surface of a substrate tray (substrate holding member) PH for holding the substrate P. These projections 65 are provided with suction holes 66 for suction-holding the substrate P. The adsorption holes 66 are respectively connected to the pipes 67 formed inside the substrate tray PH.
The flow paths 63 connected to the recovery ports 61 and the liquid recovery holes 64 are connected to one end of a pipe 68 provided outside the substrate tray PH. On the other hand, the other end of the pipe 68 is connected to a vacuum system 70 including a vacuum pump. A gas-liquid separator 71 is provided in the middle of the pipe 68, and a dryer 72 is provided between the gas-liquid separator 71 and the vacuum system 70. The liquid 1 is recovered from the recovery port 61 together with the gas around the liquid by driving the vacuum system 70. Even if the liquid 1 enters between the substrate P and the auxiliary plate 43 and goes around to the back surface side of the substrate P, the liquid is recovered from the liquid recovery holes 64 together with the ambient gas. The gas separated by the gas-liquid separator 71 and dried by the dryer 72 flows into the vacuum system 70. On the other hand, the liquid 1 separated by the gas-liquid separator 71 flows into a liquid recovery unit 73 having a tank or the like capable of storing the liquid 1. The liquid 1 collected in the liquid collection unit 73 is, for example, discarded or cleaned, and returned to the liquid supply unit 11 for reuse.
Further, the pipe 67 connected to the suction hole 66 is connected to one end of a pipe 69 provided outside the substrate tray PH. On the other hand, the other end of the pipe 69 is connected to a vacuum system 74, and the vacuum system 74 includes a vacuum pump provided outside the substrate tray PH. The substrate P supported by the projection 65 is sucked and held by the suction hole 66 by the driving of the vacuum system 74. A gas-liquid separator 75 is provided in the middle of the pipe 69, and a dryer 76 is provided between the gas-liquid separator 75 and the vacuum system 74. The gas-liquid separator 75 is connected to a liquid recovery unit 73 having a tank or the like capable of storing the liquid 1.
Next, a description will be given of a procedure of exposing a pattern of the mask M onto the substrate P by using the exposure apparatus EX described above with reference to fig. 1 and the like.
The mask M is loaded on the mask stage MST, the substrate P is loaded on the substrate stage PST, and then the control apparatus CONT drives the liquid supply portion 11 of the liquid supply mechanism 10 to supply a predetermined amount of the liquid 1 per unit time onto the substrate P through the supply pipe 15 and the supply nozzle 14. Further, the controller CONT drives the vacuum system 25 of the liquid recovery mechanism 20 in accordance with the supply of the liquid 1 by the liquid supply mechanism 10 to recover a predetermined amount of the liquid 1 per unit time through the recovery nozzle 21 and the recovery pipe 24. In this way, the immersion area AR2 of the liquid 1 is formed between the optical element 2 at the distal end of the projection optical system PL and the substrate P. Here, in order to form the liquid immersion area AR2, the controller CONT controls the liquid supply mechanism 10 and the liquid recovery mechanism 20 so that the amount of liquid supplied to the substrate P is substantially the same as the amount of liquid recovered from the substrate P. Then, the controller CONT illuminates the exposure light EL on the mask M through the illumination optical system IL, and projects the pattern image of the mask M onto the substrate P through the projection optical system PL and the liquid 1.
In the case of performing the scanning exposure, a pattern image of a part of the mask M is projected onto the projection area AR1, and the mask M is moved in the-X direction (or + X direction) at a velocity V with respect to the projection optical system PL, and in synchronization with this, the substrate P is moved in the + X direction (or-X direction) at a velocity β · V (β is a projection magnification) by the substrate stage PST. After 1 exposure area (shot area) is exposed, the next exposure area is moved to the scanning start position by stepping the substrate P, and then exposure processing is sequentially performed on each exposure area in a step-and-scan manner. In the present embodiment, the liquid 1 is set so as to flow in parallel with the moving direction of the substrate P in the same direction as the moving direction of the substrate P. That is, when the substrate P is moved in the scanning direction (-X direction) indicated by the arrow Xa (see fig. 4) to perform scanning exposure, the liquid 1 is supplied and recovered by the liquid supply mechanism 10 and the liquid recovery mechanism 20 using the supply pipe 15, the supply nozzles 14A to 14C, the recovery pipe 24, and the recovery nozzles 21A and 21B. That is, when the substrate P moves in the-X direction, the liquid 1 is supplied between the projection optical system PL and the substrate P from the supply nozzles 14(14A to 14C), and the liquid 1 on the substrate P is collected together with the gas around it from the collection nozzles 21(21A, 21B), so that the liquid 1 flows in the-X direction while filling the space between the optical element 2 at the tip of the projection optical system PL and the substrate P. On the other hand, when scanning exposure is performed by moving the substrate P in the scanning direction (+ X direction) indicated by the arrow Xb (see fig. 4), the liquid 1 is supplied and recovered by the liquid supply mechanism 10 and the liquid recovery mechanism 20 using the supply tube 15 ', the supply nozzles 14A' to 14C ', the recovery tube 24', and the recovery nozzles 21A 'and 21B'. That is, when the substrate P moves in the + X direction, the liquid 1 is supplied from the supply nozzles 14 '(14A' to 14C ') between the projection optical system PL and the substrate P, and the liquid 1 on the substrate P is collected from the collection nozzles 21' (21A ', 21B') together with the gas around them, so that the liquid 1 flows in the + X direction while filling the space between the optical element 2 at the tip of the projection optical system PL and the substrate P. In this case, for example, the liquid 1 supplied through the supply nozzle 14 is sucked between the optical element 2 and the substrate P and flows along the substrate P moving in the-X direction, so that the liquid can be easily supplied between the optical element 2 and the substrate P even if the supply energy of the liquid supply mechanism 10 (liquid supply portion 11) is small. Then, when the substrate P is scanned in the + X direction or the-X direction by switching the direction of the flow of the liquid 1 in accordance with the scanning direction, the liquid 1 can be filled between the optical element 2 and the substrate P, and exposure can be performed with high resolution and wide depth of focus.
During the exposure process, the measurement result of the flow meter 12 provided in the liquid supply mechanism 10 and the measurement result of the flow meter 27 provided in the liquid recovery mechanism 20 are always output to the control unit CONT. The controller CONT compares the measurement result of the flow meter 12, that is, the amount of the liquid supplied onto the substrate P by the liquid supply mechanism 10, with the measurement result of the flow meter 27, that is, the amount of the liquid recovered from the substrate P by the liquid recovery mechanism 20, and controls the valve 13 of the liquid supply mechanism 10 based on the comparison result. Specifically, the controller CONT obtains a difference between the amount of liquid supplied onto the substrate P (measurement result of the flow meter 12) and the amount of liquid collected from the substrate P (measurement result of the flow meter 27), determines whether or not the obtained difference exceeds a preset allowable value (threshold), and controls the valve 13. Here, as described above, the controller CONT controls the liquid supply mechanism 10 and the liquid recovery mechanism 20 so that the amount of liquid supplied onto the substrate P is substantially the same as the amount of liquid recovered from the substrate P, and therefore, if the liquid supply operation of the liquid supply mechanism 10 and the liquid recovery operation of the liquid recovery mechanism 20 are performed normally, the difference obtained as described above is substantially zero.
When the obtained difference is equal to or larger than the allowable value, that is, when the liquid recovery amount is much smaller than the liquid supply amount, the control device CONT determines that the recovery operation of the liquid recovery mechanism 20 is abnormal and the liquid 1 cannot be recovered. At this time, the controller CONT determines that an abnormality such as a failure has occurred in the vacuum system 25 of the liquid recovery mechanism 20, for example, and in order to prevent leakage of the liquid 1 due to failure of the liquid recovery mechanism 20 to recover the liquid 1 properly, the valve 13 of the liquid supply mechanism 10 is operated to shut off the flow path of the supply pipe 15, thereby stopping the supply of the liquid 1 onto the substrate P by the liquid supply mechanism 10. In this way, the controller CONT compares the amount of liquid supplied from the liquid supply mechanism 10 onto the substrate P with the amount of liquid recovered by the liquid recovery mechanism 20, detects an abnormality in the recovery operation of the liquid recovery mechanism 20 based on the comparison result, and stops the supply of the liquid 1 onto the substrate P when the excess supply of the liquid 1 is detected and the abnormality is detected. Thus, it is possible to prevent leakage of the liquid 1 to the outside of the substrate P or the substrate stage PST (substrate tray PH), intrusion of the liquid 1 to an undesired portion, or enlargement of loss due to such leakage or intrusion.
Further, the control device CONT stops power supply to the electrical equipment constituting the exposure apparatus EX in order to prevent leakage due to leakage or adhesion of the immersed liquid 1 when abnormality in the recovery operation of the liquid recovery mechanism 20 is detected. Here, as the electric devices, linear motors 47 and 48 for moving the substrate stage PST and the like can be cited. Since the linear motors 47 and 48 are positioned at positions where the liquid 1 leaking to the outside of the substrate stage PST is likely to adhere to and infiltrate, the control device CONT stops the supply of power to the linear motors 47 and 48, thereby preventing the leakage due to the adhesion of the liquid 1. In addition to the linear motors 47 and 48, examples of the electric device include a sensor (a photomultiplier (フオトマル)) provided on the substrate stage PST and receiving the exposure light EL with respect to the substrate stage PST. Alternatively, the electric device may be various actuators such as a piezoelectric element for adjusting the position of the substrate tray PH in the Z-axis direction and the tilt direction. When an abnormality is detected, the power supply to all the electrical devices constituting the exposure apparatus EX may be stopped, or the power supply to some of the electrical devices may be stopped. Here, when the control unit CONT detects an abnormality in the recovery operation of the liquid recovery mechanism 20, for example, by stopping power supply to an electric device (high-voltage device) such as a linear motor, a piezoelectric element used at around 0 to 150V, or a photomultiplier tube (sensor) used at around 300 to 900V, leakage of electricity can be prevented, and the influence of the leakage of electricity on peripheral devices can be suppressed.
When an abnormality in the recovery operation of the liquid recovery mechanism 20 is detected, the control device CONT stops driving of the air bearing 42 for moving the substrate stage PST in a non-contact manner with respect to the guide surface 41A of the substrate base plate 41, for example. The air bearing 42 has a discharge port 42B for discharging gas (air) against the upper surface (guide surface) 41A of the substrate base plate 41 and a suction port 42A for sucking the gas between the lower surface (bearing surface) of the substrate table PST and the guide surface 41A, and a certain gap is maintained between the lower surface of the substrate table PST and the guide surface 41A by a balance between a repulsive force generated by the discharge of the gas from the discharge port 42B and a suction force generated by the suction port 42A, but when an abnormality in the recovery operation of the liquid recovery mechanism 20 is detected, the control device CONT stops the operation of the air bearing 42, particularly the suction from the suction port 42A, in order to prevent the leaked liquid 1 from flowing (entering) into the suction port 42A of the air bearing 42. This prevents the liquid 1 from flowing into the vacuum system connected to the air inlet 42A, and prevents problems such as failure of the vacuum system due to the inflow of the liquid 1.
Further, the other member may be provided with the protrusion 65 or the suction hole 66 for holding the substrate P, and when the other member is suction-held on the substrate tray PH, the control device CONT may stop the suction from the suction hole (suction port) for suction-holding the other member.
Further, the control unit CONT drives the alarm device K when detecting an abnormality in the recovery operation of the liquid recovery mechanism 20. The alarm device K can issue an alarm using a warning lamp, an alarm sound, a display, or the like, so that, for example, an operator can know that the liquid 1 leaks or enters the exposure apparatus EX.
When an abnormality in the recovery operation of the liquid recovery mechanism 20 is detected, the control device CONT increases the liquid recovery amount of the recovery device 60. Specifically, the driving amount (driving force) of the vacuum system 70 of the recovery device 60 is increased. Since the driving of the recovery device 60 (vacuum system 70) is a vibration source, it is preferable to reduce or prevent the driving force of the recovery device 60 during the exposure process, but when an abnormality in the recovery operation of the liquid recovery mechanism 20 is detected and the possibility of leakage of the liquid 1 is detected, the control device CONT can prevent leakage of the liquid 1 outside (at least outside the recovery port 61) of the substrate stage PST (substrate tray PH) or expansion of the leakage by increasing the driving force of the recovery device 60.
While the exposure region near the center of the substrate P is being exposed, the liquid 1 supplied from the liquid supply mechanism 10 is recovered by the liquid recovery mechanism 20. On the other hand, as shown in fig. 5, when the edge area of the substrate P is exposed, the liquid 1 is continuously held between the projection optical system PL and the substrate P by the auxiliary plate 43 when the liquid immersion area AR2 is in the vicinity of the edge area of the substrate P, but a part of the liquid 1 may flow out to the outside of the auxiliary plate 43, and the flowed-out liquid 1 is collected by the collection port 61 in which the liquid absorbing member 62 is disposed. Here, the controller CONT starts to drive the liquid supply mechanism 10 and the liquid recovery mechanism 20 and starts to operate the recovery device 60. Therefore, the liquid 1 collected from the collection port 61 is sucked by the vacuum system 70, and is collected together with the ambient air through the flow path 63 and the duct 68. The liquid 1 flowing into the gap between the substrate P and the auxiliary plate 43 is collected through the liquid collection holes 64, together with the ambient air, through the flow path 63 and the duct 68. At this time, the gas-liquid separator 71 separates the liquid 1 and the gas recovered from the recovery port 61. The gas separated by the gas-liquid separator 71 is dried by a dryer 72 and then flows into the vacuum system 70. Thus, the problem of the liquid component flowing into the vacuum system 70 can be prevented. On the other hand, the liquid separated by the gas-liquid separator 71 is recovered in the liquid recovery unit 73.
At this time, since a part of the liquid 1 supplied from the liquid supply mechanism 10 is collected by the collection device 60, the amount of the liquid collected by the liquid collection mechanism 20 decreases, and as a result, the amount of the liquid collected by the flow meter 27 of the liquid collection mechanism 20 decreases. In this case, even if the liquid 1 does not leak, the controller CONT may erroneously determine that an abnormality occurs in the recovery operation of the liquid recovery mechanism 20 by comparing the measurement results of the flow meter 12 of the liquid supply mechanism 10 and the flow meter 27 of the liquid recovery mechanism 20. Therefore, a flow meter for measuring the amount of the liquid to be recovered is provided between the gas-liquid separator 71 and the liquid recovery unit 73 in the recovery device 60, and the control device CONT determines the total recovery amount of the liquid from the measurement result of the flow meter of the recovery device 60 and the measurement result of the flow meter 27 of the liquid recovery mechanism 20, and compares the determined total recovery amount of the liquid with the measurement result of the flow meter 12 of the liquid supply mechanism 10. Based on the result of the comparison, the control unit CONT judges whether or not an abnormality occurs in the liquid recovery operation of the liquid recovery mechanism 20, and based on the result of the judgment, can perform measures such as stopping the liquid supply operation of the liquid supply mechanism 10, stopping the power supply, and stopping the suction operation from the suction port.
Further, when the measured value of the flow meter provided in the recovery device 60 becomes a large value exceeding a preset allowable value, the control device CONT judges that a large amount of the liquid 1 has flowed out to the outside of the substrate P, and may prevent the liquid supply mechanism 10 from leaking to the outside of the substrate stage PST (substrate tray PH) or the like.
The liquid 1 flowing out to the outside of the substrate P may enter the gap between the substrate P and the auxiliary plate 43 and reach the back surface side of the substrate P. The liquid 1 that has entered the back surface side of the substrate P may also flow into the suction hole (suction port) 66 for suction-holding the substrate P. In this case, the adsorption holes 66 provided in the substrate tray PH for adsorbing and holding the substrates P are connected to the vacuum system 74 through the pipes 67 and 69, and a gas-liquid separator 75 and a dryer 76 for drying the gas separated by the gas-liquid separator 75 are provided in the middle of the connection. Therefore, even if the liquid 1 flows into the adsorption hole 66, the liquid 1 flowing from the adsorption hole 66 can be recovered in the liquid recovery portion 73, and the problem that the liquid component flows into the vacuum system 74 can be prevented.
Since there is a possibility that a problem such as holding of the substrate P may occur when the liquid 1 enters from the adsorption hole 66, when a flow meter is disposed between the pipe 69 or the gas-liquid separator 75 and the liquid recovery unit 73 and the entry of the liquid from the adsorption hole 66 is detected by the flow meter, it is determined that an abnormal situation occurs, and at least 1 of the above-described stop of the liquid supply operation, the power supply stop, and the stop of the suction from the suction port is performed.
In the case where the gas-liquid separator 75 is not provided in the pipe 69 connected to the adsorption hole 66, when abnormality in the recovery operation of the liquid recovery mechanism 20 or the recovery device 60 is detected, the driving of the vacuum system 74 (suction system) may be stopped to stop the suction from the adsorption hole 66 in order to prevent the liquid 1 from flowing into the adsorption hole (suction port).
As described above, since the supply of the liquid 1 onto the substrate P by the liquid supply mechanism 10 is stopped when an abnormality such as a leakage or an intrusion of the liquid 1 is detected, the leakage of the liquid 1, the expansion of the leakage, the flooding, or the like can be prevented. Even when an abnormality such as leakage or intrusion of the liquid 1 occurs, the power supply to the electric devices such as the linear motors 47 and 48 constituting the exposure apparatus EX is stopped, thereby preventing the occurrence of electric leakage and the expansion of loss due to electric leakage. Further, in order to suck and hold the suction port 42A of the air bearing 42 or the substrate P, suction from each suction port communicating with a vacuum system such as the suction hole 66 provided in the substrate tray PH is stopped, and thus the problem that the liquid 1 flows into the vacuum system connected to the suction port can be prevented. Further, when the liquid and the gas around the liquid are recovered from the suction port such as the recovery nozzle 21, the recovery port 61, or the adsorption hole 66, the liquid and the gas sucked from the suction port are separated into gas and liquid by the gas-liquid separator, and the gas separated by the gas-liquid separator is dried by the dryer, so that the liquid component (wet gas or the like) is prevented from flowing into the vacuum system, and the influence of the liquid on the vacuum system can be reduced. In addition, although the present embodiment is configured to recover the liquid from the suction port together with the gas around the suction port, the amount of the recovered liquid can be accurately measured by separating the liquid and the gas recovered by the gas-liquid separator.
In the above embodiment, the failure (operation abnormality) of the vacuum system 25 has been described as an example of the abnormality of the recovery operation of the liquid recovery mechanism 20, but the failure of the vacuum system 25 and the operation abnormality of the gas-liquid separator 22 may be mentioned, for example. That is, even if the liquid 1 on the substrate P can be recovered by the recovery nozzle 21, the gas-liquid separator 22 cannot sufficiently separate the liquid and the gas recovered from the recovery nozzle 21, and the amount of the liquid measured by the flow meter 27 is less than a predetermined value. In this case, since the liquid component flowing into the vacuum system 25 is increased, the vacuum system 25 may be broken, and the like, and therefore, the control unit CONT stops the liquid supply operation of the liquid supply mechanism 10 and the liquid recovery operation of the liquid recovery mechanism 20 (vacuum system 25), thereby preventing the leakage of the liquid 1 and the breakage of the vacuum system 25.
In the present embodiment, the controller CONT controls the liquid supply mechanism 10 and the liquid recovery mechanism 20 so that the amount of liquid supplied onto the substrate P is substantially the same as the amount of liquid recovered from the substrate P, respectively. Therefore, if the liquid supply operation of the liquid supply mechanism 10 and the liquid recovery operation of the liquid recovery mechanism 20 are performed normally, respectively, the obtained difference is substantially zero, and the allowable value is set to a small value in advance in accordance with the difference. On the other hand, for example, in the case where the liquid 1 to be used has high volatility, even if the liquid supply operation of the liquid supply mechanism 10 and the liquid recovery operation of the liquid recovery mechanism 20 are performed normally, respectively, and the liquid 1 is volatilized on the substrate P, the measurement value obtained by the flow meter 27 of the liquid recovery mechanism 20 may be made smaller than the measurement value obtained by the flow meter 12 of the liquid supply mechanism 10. Therefore, the controller CONT preferably sets the allowable value in advance according to the liquid 1 (volatility) to be used or the environment in which the substrate P is placed, and controls the valve 13 based on the comparison result between the set allowable value and the obtained difference.
In the above embodiment, the abnormality in the flow state of the liquid 1 is detected by comparing the liquid supply amount of the liquid supply mechanism 10 and the liquid recovery amount of the liquid recovery mechanism 20, but the abnormality may be detected based on only the supply amount of the liquid supply mechanism 10 or only the recovery amount of the liquid recovery mechanism 20. Further, the control device CONT may take measures such as stopping the liquid supply operation of the liquid supply mechanism 10, stopping the power supply, and stopping the suction operation from the suction port, when mechanical or electrical abnormality of the liquid supply mechanism 10 or the liquid recovery mechanism 20 is detected, not limited to the flow rate of the liquid.
In the present embodiment, since the gas around the recovery nozzle 21 is also recovered together with the liquid 1, the gas-liquid separator 22 is used to separate the recovered liquid from the gas and the flow meter 27 is used to measure the amount of the separated liquid in order to measure a more accurate liquid recovery amount. For this reason, the liquid amount measured by the flow meter 27 may also vary due to the gas-liquid separation capability of the gas-liquid separator 22. Therefore, the controller CONT may set the allowable value in accordance with the gas-liquid separator 22 (gas-liquid separation capability) to be used.
In the present embodiment, when an abnormality in the liquid recovery operation of the liquid recovery mechanism 20 is detected, the liquid supply operation of the liquid supply mechanism 10 is stopped, the power supply to the electrical device is stopped, and the suction operation from the suction port is stopped.
In the present embodiment, since the gas around the liquid 1 is also recovered from the recovery nozzle 21 of the liquid recovery mechanism 20 together with the liquid 1, the gas-liquid separator 22 is used to separate the liquid and the gas in order to measure the amount of the recovered liquid with a flow meter 27 with higher accuracy, but in the case of a configuration in which the liquid recovery mechanism 20 recovers only the liquid 1 from the recovery nozzle 21, the liquid recovery amount can be determined by measuring the amount of the recovered liquid without separating the liquid from the gas-liquid separator 22.
However, in the present embodiment, the liquid supply operation of the liquid supply mechanism 10, the supply of power to the electric device, or the suction operation from the suction port may be stopped when an abnormality of the recovery operation of the liquid recovery mechanism 20 is detected, but at least one of the stop of the liquid supply operation, the stop of the power supply, and the stop of the suction operation from the suction port may be performed when an abnormality of the positional relationship between the substrate table (movable member) PST capable of moving while holding the substrate P and the projection optical system PL is detected. Here, the abnormal positional relationship between the substrate stage PST and the projection optical system PL is a state in which the liquid 1 cannot be held under the projection optical system PL, and includes an abnormality in the positional relationship in at least one of the Z-axis direction and the XY direction. That is, even if the supply operation of the liquid supply mechanism 10 and the recovery operation of the liquid recovery mechanism 20 are normal, for example, when an abnormality occurs in the operation of the substrate stage PST and the substrate stage PST is disposed at a position shifted in the XY direction from a desired position with respect to the projection optical system PL, in this case, a state occurs in which the liquid immersion area AR2 of the liquid 1 cannot be formed satisfactorily between the projection optical system PL and the substrate P held on the substrate stage PST (a state in which the liquid 1 cannot be held on the lower surface of the projection optical system PL). In this case, the liquid 1 leaks outside the substrate P, outside the substrate tray PH, or the movable mirror 45 of the substrate stage PST (substrate tray PH) is immersed in water. Since the liquid recovery mechanism 20 cannot recover the predetermined amount of the liquid 1 in this way, the flow meter 27 of the liquid recovery mechanism 20 outputs a measurement result of a value smaller than the predetermined value to the control unit CONT. The controller CONT can detect an abnormality in the position of the substrate stage PST such as the occurrence of leakage of the liquid 1 from the measurement result of the flow meter 27. When the abnormality is detected, the control device CONT stops the liquid supply operation, stops the power supply, stops the suction operation from the suction port, and the like.
Further, the liquid immersion area AR2 sets the distance between the projection optical system PL and the substrate P to a predetermined distance (about 0.1mm to 1 mm) of such a degree that the liquid immersion area AR2 can be formed by the surface tension of the liquid 1, but when a problem occurs in the position control of the substrate stage PST in the Z-axis direction, for example, the distance between the projection optical system PL and the substrate P on the substrate stage PST increases, and there is a possibility that the liquid 1 cannot be held under the projection optical system PL. In this case, the liquid 1 leaks to the outside of the substrate P or the outside of the substrate stage PST (substrate tray PH), and the liquid recovery mechanism 20 cannot recover the predetermined amount of the liquid 1, and the flow meter 27 of the liquid recovery mechanism 20 outputs the measurement result of a value smaller than the predetermined value to the control unit CONT. The controller CONT can detect a positional abnormality of the substrate stage PST such as the occurrence of the leakage of the liquid 1 based on the measurement result of the flow meter 27. When detecting the abnormality, the control device CONT stops the liquid supply operation, stops the power supply, stops the suction operation from the suction port, and the like.
In order to detect an abnormality in the positional relationship of the substrate stage PST with respect to the projection optical system PL, the XY-direction position of the substrate stage PST is detected by, for example, the laser interferometer 46 without using the measurement result of the flow meter 27 of the liquid recovery mechanism 20, and the abnormality in the positional relationship is detected based on the position detection result. The control device CONT may compare the substrate stage position detection result obtained by the laser interferometer 46 with a preset allowable value, and stop the supply operation of the liquid 1 or the like when the stage position detection result of the laser interferometer 46 exceeds the allowable value. Further, the position of the substrate stage PST in the Z axis direction may be detected by the focus detection system 56, the stage position detection result obtained by the focus (focus) detection system 56 may be compared with a preset allowable value, and the control device CONT may stop the supply operation of the liquid 1 or the like when the detection result of the focus detection system 56 exceeds the allowable value. In this way, the control device CONT detects an abnormality in the positional relationship between the projection optical system PL and the substrate stage PST based on the detection result of the substrate stage position detection device including the laser interferometer 46 and the focus detection system 56, and when an abnormality is detected, performs stopping of the liquid supply operation, stopping of the power supply to the electrical equipment, stopping of the suction operation from the suction port, and the like.
Further, when an error occurs in the laser interferometer 46, the control unit CONT may stop the liquid supply operation of the liquid supply mechanism 10. Here, the error of the laser interferometer 46 includes a state in which the position measurement of the substrate stage PST is not performed due to some reason such as a failure of the laser interferometer 46 itself or a foreign substance placed on the optical path of the measurement light of the interferometer. When an error occurs in the laser interferometer 46, the control device CONT cannot grasp the position of the substrate stage PST and cannot control the position of the substrate stage PST at the same time. In this case, an abnormality occurs in the positional relationship between the projection optical system PL and the substrate stage PST, and there is a risk of leakage and outflow of the liquid 1. Therefore, when an error occurs in the laser interferometer 46, the liquid supply mechanism 10 stops supplying the liquid, thereby preventing the liquid 1 from leaking.
Similarly, when an error occurs in the measurement system (the focus detection system 56 in the present embodiment) for controlling the position of the substrate stage PST in the Z-axis direction, an abnormality occurs in the positional relationship between the projection optical system PL and the substrate stage PST, and there is a risk of leakage and outflow of the liquid 1, so that the control device CONT stops the liquid supply operation of the liquid supply mechanism 10 when an error occurs in the focus detection system 56.
The abnormality in the positional relationship between the substrate stage PST (substrate tray PH) and the projection optical system PL in the Z-axis direction is not limited to the focus detection system 56, and a non-optical detection system such as a capacitance sensor may be used.
In addition, the positional relationship between the image plane of the projection optical system PL and the surface of the substrate stage PST (substrate P) may be managed using an interferometer. The management of the positional relationship between the image plane of the projection optical system PL and the surface of the substrate stage PST (substrate P) using an interferometer is disclosed in, for example, U.S. patent 6,202,964, and the disclosure thereof is incorporated as a part of the description herein within the scope permitted by the statute of the country specified or selected by the international application.
In the above embodiment, although the case where an abnormality occurs during the exposure operation has been described, the same applies to the case where an abnormality occurs when the substrate P is not exposed.
In the above embodiment, the supply of the liquid is stopped when an abnormality is detected in the supply of the liquid, but the supply of the liquid can be stopped when the supply of the liquid is started even when an abnormality such as a positional relationship between the projection optical system PL and the substrate stage PST is detected.
Next, embodiment 2 of exposure apparatus EX of the present invention will be described. In the following description, the same or equivalent components as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will be simplified or omitted. In the present embodiment, a leak of the liquid 1 to the outside of the substrate P or the substrate stage PST (substrate tray PH) or the like is optically detected by using a detector including an optical fiber, and when the leak or the intrusion of the liquid 1 is detected, at least 1 of the operation of supplying the liquid by the liquid supply mechanism 10, the stop of the power supply to the electric device, and the stop of the suction operation from the suction port is performed.
The detection principle of the detector for detecting a leak of the liquid 1 is explained below with reference to fig. 6 and 7. In this embodiment, an optical fiber is used as the detector. Fig. 6 is a schematic configuration diagram showing a general optical fiber. In fig. 6, an optical fiber 80' has a core portion 81 that transmits light and a cladding portion 82 provided around the core portion 81 and having a refractive index smaller than that of the core portion 81. In the optical fiber 80', light is confined in and transmitted through a core portion 81 having a higher refractive index than a cladding portion 82.
Fig. 7 is a schematic configuration diagram showing an optical fiber 80 of the present embodiment. In fig. 7, an optical fiber 80 is an optical fiber (unclad fiber) having a core 81 for transmitting light and no cladding portion provided around the core. The core 81 of the optical fiber 80 has a refractive index nc higher than a refractive index na of a gas (air in the present embodiment) around it, and has a refractive index na < nc < nw lower than a refractive index nw of the liquid (pure water in the present embodiment) 1. Therefore, when the periphery of the optical fiber 80 is filled with air, the incident angle θ of light is only required0Satisfies sin theta0If na/nc is greater, light is confined in and transmitted through a core 81 having a refractive index nc higher than that of air. That is, the light entering from the light emitting end of the optical fiber 80 is emitted from the light emitting end without being attenuated greatly. However, when the liquid (pure water) 1 is attached to the surface of the optical fiber 80, nc < nw is obtained, and therefore, the total reflection condition sin θ cannot be satisfied at all incident angles at the portion where water is attached0In this solution, ═ nw/ncSince total reflection does not occur at the interface between the body 1 and the optical fiber 80, light leaks to the outside from the liquid-adhering portion of the optical fiber 80. Therefore, the amount of light incident from the incident end of the optical fiber 80 decreases when it exits from the exit end. Therefore, by providing the optical fiber 80 at a predetermined position of the exposure apparatus EX and measuring the light quantity at the emission end of the optical fiber 80, the control apparatus CONT can detect whether or not the liquid 1 is attached to the optical fiber 80, that is, whether or not the liquid 1 leaks. Since the refractive index of air is about 1 and the refractive index of water is about 1.4 to 1.6, the core 81 is preferably made of a material (quartz, glass having a specific composition, or the like) having a refractive index of about 1.2, for example.
The amount of the liquid 1 adhering to the optical fiber 80 can be determined from the attenuation amount of the light emitted from the emission end of the optical fiber 80. That is, the amount of optical attenuation depends on the area of the portion of the liquid 1 attached to the optical fiber, and when a small amount of the liquid 1 is attached to the periphery of the optical fiber 80, the amount of attenuation of the light at the output end is small, and when a large amount of the liquid 1 is attached, the amount of attenuation is large. Therefore, it is considered that the area of the portion where the liquid 1 adheres depends on the amount of liquid leakage, and therefore, the amount of liquid 1 leakage can be obtained by measuring the amount of light at the output end of the optical fiber 80. When the measured value of the light amount at the exit end of the optical fiber is compared with a plurality of preset threshold values (reference values) and the measured value exceeds each threshold value, a specific signal is emitted, and the leakage amount of the liquid 1 can be detected in stages.
Fig. 8 is a side view showing a state where the optical fiber 80 of the detector is disposed around the substrate stage PST (substrate tray PH), and fig. 9 is a plan view. As shown in fig. 8 and 9, the optical fiber 80 is disposed around the substrate stage PST (substrate tray PH). A light projecting portion 83 that can project light to the optical fiber 80 is connected to an incident end of the optical fiber 80, a light receiving portion 84 is connected to an emitting end of the optical fiber 80, and the light receiving portion 84 can receive light that is transmitted through the optical fiber 80 and emitted from the emitting end. The controller CONT determines the light attenuation ratio of the exit end portion of the optical fiber 80 with respect to the entrance end portion based on the light amount of the light incident on the optical fiber 80 from the light projecting portion 83 and the light amount of the light received by the light receiving portion 84, and determines whether or not the liquid 1 adheres to the optical fiber 80, that is, whether or not the liquid 1 leaks to the outside of the substrate stage PST (substrate tray PH) based on the determination result. When determining that the liquid 1 leaks, the control device CONT stops the liquid supply operation by the liquid supply mechanism 10, stops the power supply to the electrical equipment, and stops the suction operation from the air inlet.
The optical fiber 80 may be disposed on the upper surface of the substrate stage PST (substrate tray PH), particularly around the recovery port 61, or may be disposed on or around the movable mirror 45 in order to check the immersion (immersion) of the movable mirror 45.
Fig. 10 shows an example in which the optical fiber 80 is disposed around the air bearing 42 provided on the lower surface of the substrate stage PST and around the substrate base plate (base member) 41 that movably supports the substrate stage PST. Since the optical fiber 80 can be bent arbitrarily, it can be wound around an arbitrary position where the liquid 1 is likely to leak, such as the substrate stage PST (substrate tray PH), the air bearing 42, and the substrate base plate 41, and can be freely arranged and disposed in an arbitrary form. In particular, by attaching the optical fiber 80 to the periphery of the air bearing 42, it is possible to detect well whether the liquid 1 adheres to (leaks from) the vicinity of the air bearing 42, and to prevent the liquid 1 from flowing into the air inlet 42A of the air bearing 42.
However, in the optical fiber 80, when the distance from the incident end to the emission end is long, it may be difficult to determine the position where the liquid 1 adheres to the optical fiber 80, that is, the position where the liquid 1 leaks. Therefore, as shown in fig. 11, the position of the leakage of the liquid 1 can be determined by arranging the plurality of optical fibers 80 in a matrix in 2 dimensions. In FIG. 11, detector 90 has fiber 1 80A and fiber 2 80B; a plurality of the 1 st optical fibers 80A are arranged in a2 nd direction (X-axis direction) orthogonal to the 1 st direction with the 1 st direction (Y-axis direction) as a longitudinal direction; the 2 nd optical fiber 80B is provided in plural along the 1 st direction with the 2 nd direction as the longitudinal direction. These 1 st and 2 nd optical fibers 80A and 80B are arranged in a matrix (mesh). The respective incident end portions of the plurality of 1 st optical fibers 80A are collected, and the collected portion thereof is connected to the emission end portion of the collection optical fiber 85A. The incident end of the collection fiber 85A is connected to the light projecting section 83A. On the other hand, the output ends of the plurality of 1 st optical fibers 80A are connected to a light receiving portion 84A constituted by, for example, a 1-dimensional CCD line sensor or the like. Similarly, the respective incident end portions of the plurality of 2 nd optical fibers 80B are collected, and the collected portion thereof is connected to the emission end portion of the collection optical fiber 85B. The incident end of the collection fiber 85B is connected to the light projecting section 83B. On the other hand, each of the emission end portions of the plurality of 2 nd optical fibers 80B is connected to a light receiving portion 84B configured by, for example, a 1-dimensional CCD line sensor or the like.
The light emitted from the light projecting section 83A is transmitted along the collective optical fiber 85A, and then branched to the 1 st optical fibers 80A. The light beams respectively incident from the incident end portions of the 1 st optical fiber 80A are transmitted through the 1 st optical fiber 80A, and then exit from the exit end portions to be received by the light receiving portion 84A. The light receiving portions 84A detect the light quantities of the light emitted from the emission end portions of the plurality of 1 st optical fibers 80A, respectively. Here, as shown in fig. 11, when the liquid 1 adheres to a specific 1 st optical fiber 80AL among the plurality of 1 st optical fibers 80A, the light amount at the emission end portion of the 1 st optical fiber 80AL decreases. The light reception result of the light receiving portion 84A is output to the control device CONT. Similarly, the light emitted from the light projecting section 83B is transmitted by the collective optical fiber 85B, and then branched into the plurality of 2 nd optical fibers 80B. The light beams respectively incident from the incident end portions of the 2 nd optical fibers 80B are transmitted through the 2 nd optical fibers 80B, and then exit from the exit end portions to be received by the light receiving portion 84B. The light receiving portions 84B detect the light amount of light emitted from the respective emission end portions of the plurality of 2 nd optical fibers 80B, respectively. Here, as shown in fig. 11, when the liquid 1 adheres to a specific 2 nd optical fiber 80BL among the plurality of 2 nd optical fibers 80B, the light amount at the emission end portion of the 2 nd optical fiber 80BL decreases. The light reception result of the light receiving portion 84B is output to the control device CONT. The controller CONT can determine the position of the leakage of the liquid 1 (the position where the leaked liquid 1 adheres to the detector 90) to be in the vicinity of the intersection of the 1 st optical fiber 80AL and the 2 nd optical fiber 80BL from the light receiving results of the light receiving portions 84A and 84B, respectively.
Fig. 12 is a diagram showing an example in which a detector 90 having optical fibers 80A, 80B arranged in a matrix is arranged to a linear motor 47 (stator 47A) as an electromagnetic drive source for driving the substrate stage PST. By disposing the detector 90 to the linear motor 47, the position of the liquid 1 that leaks to the outside of the substrate stage PST and adheres to the linear motor 47 can be determined. By specifying the position of the leaked liquid 1, the operation of removing the leaked liquid 1 can be performed with good efficiency.
When the liquid 1 is water and the leaked liquid (water) is removed, the removal work (wiping work) is performed by using absolute alcohol, whereby water can be removed satisfactorily, and the removal work can be performed smoothly since alcohol is volatilized immediately.
As shown in the schematic diagram of fig. 13, the position of the liquid 1 adhering to the surface of the optical fiber 80 can be determined by making the pulsed light incident from the incident end of the optical fiber 80. When the liquid 1 adheres to the surface of the optical fiber 80, the pulse light L1 incident from the incident end of the optical fiber 80 is reflected at the adhesion position of the liquid 1, and a phenomenon occurs in which the reflected light L2 returns to the incident end side again. Therefore, an optical element such as a polarizing beam splitter is provided on the incident side, and the reflected light is guided to a light receiver by the optical element and detected. From the detection result, the distance between the incident end and the position where the liquid 1 adheres can be obtained from the time difference between the time when the pulsed light L1 enters the optical fiber 80 and the time when the reflected light L2 is received by the incident end and the speed of light transmitted through the optical fiber 80, and the position where the liquid 1 adheres (the position where the liquid 1 leaks) can be specified. The speed of light transmitted through the optical fiber 80 varies depending on the material forming the optical fiber 80 (core 81), and therefore can be determined from the material forming the optical fiber 80.
Next, embodiment 3 of exposure apparatus EX according to the present invention will be described. In the present embodiment, when the leakage of the liquid 1 is optically detected by using a detector including a prism (optical element) and the leakage of the liquid 1 is detected, at least 1 of the stop of the liquid supply operation of the liquid supply mechanism 10, the stop of the power supply of the electric device, and the stop of the suction operation from the air inlet is performed.
The detection principle of the detector for detecting leakage of the liquid 1 is explained below with reference to fig. 14 and 15. In this embodiment, a prism is used. Fig. 14 is a diagram showing a schematic configuration of the detector 100 using a prism. In fig. 14, the detector 100 includes a prism 101, a light projecting portion 102 attached to a1 st surface 101A of the prism 101 and projecting light to the prism 101, and a light receiving portion 103 attached to a2 nd surface 101B of the prism 101 and receiving light reflected by a 3 rd surface 101C of the prism 101 from the light emitted from the light projecting portion 102. The 1 st surface 101A and the 2 nd surface 101B are substantially perpendicular to each other.
The prism 101 has a higher refractive index than the gas (air in the present embodiment) around it, and has a lower refractive index than the liquid (pure water in the present embodiment) 1. When the periphery of the prism 101 is filled with air, the prism refractive index is selected so that the light projected from the light projecting portion 102 to the 3 rd surface 101C is totally reflected by the 3 rd surface 101C. For this reason, the light emitted from the light projecting portion 102 is received by the light receiving portion 103 without attenuating a large amount of light.
Fig. 15 is a diagram showing a state in which the liquid 1 adheres to the 3 rd surface 101C of the prism 101 of the detector 100. In fig. 15, the light projected from the light projecting portion 102 onto the 3 rd surface 101C is not totally reflected by the 3 rd surface 101C due to the existence surface of the liquid 1, and a part (or all) of the light component leaks to the outside from the liquid adhering portion of the prism 101. Therefore, the light receiving portion 103 can detect whether or not the liquid 1 adheres to the 3 rd surface 101C of the prism 101 based on the received light quantity (light information) because the light quantity of the light component reaching the 2 nd surface 101B in the light emitted from the light projecting portion 102 is attenuated. Therefore, by providing the detector 100 having the prism 101 at a predetermined position of the exposure apparatus EX, it is possible to detect whether the liquid 1 is attached to the prism 101, that is, whether the liquid 1 leaks, by the CONT from the light receiving result of the light receiving portion 103.
Fig. 16 is a plan view showing an example in which the detector 100 having the prism 101 described above is disposed around the substrate stage PST. In fig. 16, a plurality of detectors 100 are mounted around the substrate stage PST (substrate tray PH) at predetermined intervals in a state where the 3 rd surface 101C of the prism 101 faces upward. The control device CONT obtains the attenuation ratio of the amount of emitted light with respect to the amount of incident light on the prism 101 from the amount of light incident on the prism 101 from the light emitting portions 102 of the detectors 100 and the amount of light received by the light receiving portion 103, and determines whether or not the liquid 1 adheres to the prism 101, that is, whether or not the liquid 1 leaks to the outside of the substrate stage PST (substrate tray PH), based on the obtained result. When the control device CONT determines that the liquid 1 leaks, the supply operation of the liquid by the liquid supply mechanism 10 is stopped, the power supply to the electrical device is stopped, the suction operation from the air inlet is stopped, and the like.
In the present embodiment, the controller CONT can easily specify the leakage position of the liquid 1 based on the detection results of the plurality of detectors 100 and the mounting position information of the detectors 100. Further, since the prism 101 is small, it can be easily attached to an arbitrary position of the exposure apparatus EX, and the installation work is also good.
The above detector 100 may also be applied to a water level gauge (level gauge). Fig. 17 is a schematic view showing that a plurality of detectors 100 are mounted in a height direction (Z-axis direction) on a wall surface of a tank 110 capable of storing liquid (water) 1. The wall surface of the case 110 is transparent, and the 3 rd surface 101C of the prism 101 is attached to the detector 100 in contact with the wall surface of the case 110. Since the light receiving signal of the detector 100 (light receiving portion 103) that detects the liquid 1 in the tank 110 among the plurality of detectors 100 shows a value lower than the light receiving signal of the detector 100 (light receiving portion 103) that does not detect the liquid 1, the control device CONT can determine the liquid level (water level) of the liquid 1 in the tank 110 from the detection results (light receiving results) of the plurality of detectors 100 and the mounting position information of each of the plurality of detectors 100 with respect to the tank 110, and thus can determine the amount of liquid in the tank 110.
Fig. 18 is a schematic configuration diagram showing an example in which a tank 110 having a detector 100 constituting a water level gauge is applied to a part of the liquid recovery mechanism 20. The liquid recovery mechanism 20 shown in fig. 18 includes a recovery nozzle 21, a vacuum system 25 connected to the recovery nozzle 21 via a recovery pipe 24, and a gas-liquid separator 22 and a dryer 23 provided in the middle of the recovery pipe 24. The liquid 1 separated by the gas-liquid separator 22 is received in the tank 110 having the detector 100 through the 2 nd recovery pipe 26. That is, in the present embodiment, the tank 110 is provided instead of the flow meter 27 of the liquid recovery mechanism 20 described with reference to fig. 3. The detection result of the detector 100 is output to the control unit CONT, and the control unit CONT determines the amount of liquid collected by the collection nozzle 21 from the detection result of the detector 100. The controller CONT compares the amount of liquid collected from the collection nozzle 21 with the amount of liquid supplied from the liquid supply mechanism 10, thereby detecting an abnormality in the collection operation of the liquid collection mechanism 20. The tank 110 is connected to the liquid recovery portion 28 through a pipe 28A, and a valve 28B is provided on the pipe 28A. When the tank 110 is filled to a predetermined amount or more (or periodically), the controller CONT opens the flow path 28A by operating the valve 28B to recover the liquid 1 in the tank 110 by the liquid recovery section 28.
In the embodiment shown in fig. 18, the detector 100 is attached to each of the supply pipe 15 and the recovery pipe 24. Here, the supply pipe 15 and the recovery pipe 24 are each formed of a transparent material, and the detector 100 is attached to the outer surface of the pipe so that the detection surface 100c of the detector 100 is in close contact therewith. The control device CONT detects whether or not the liquid 1 flows through the supply tube 15 based on the result of light reception by the light receiving portion 103 of the detector 100 attached to the supply tube 15. That is, since the value of the light receiving signal of the light receiving portion 103 becomes smaller in the case of circulation than in the case of not circulating the liquid 1 to the supply pipe 15, the control device CONT can detect whether or not the liquid 1 has circulated to the supply pipe 15, that is, whether or not the supply operation of the liquid supply mechanism 10 has been normally performed, based on the light receiving result of the light receiving portion 103. Similarly, the controller CONT detects whether or not the liquid 1 flows through the recovery pipe 24, that is, whether or not the recovery operation of the liquid recovery mechanism 20 is normally performed, based on the light reception result of the light receiving portion 103 of the detector 100 attached to the recovery pipe 24. In this way, the detector 100 can also be used as a liquid presence sensor for optically detecting whether or not the liquid 1 is flowing through the supply pipe or the recovery pipe.
Further, by mounting the detector 100 having the prism 101, for example, near the tip of the projection optical system PL (near the optical element 2), it is also possible to detect whether or not the liquid 1 fills between the projection optical system PL and the substrate P using the detector 100.
In the above embodiment, the leakage of the liquid 1 and the presence or absence of the liquid 1 are optically detected using the optical fiber 80 or the prism 101, but may be electrically detected using a capacitance sensor or the like.
When the liquid 1 is water, the leakage of the liquid 1 or the presence or absence of the liquid 1 may be electrically detected by a water leakage sensor which is constituted by 2 wires separated by a predetermined interval and detects the leakage of the liquid 1 by the presence or absence of conduction between the 2 wires. In the present embodiment, since water is used as the liquid 1, the water leakage sensor having the above-described configuration can be used. When ultrapure water is used for the liquid 1, the ultrapure water has no conductivity, and therefore, the presence or absence of the liquid 1 cannot be detected by the water leakage sensor. In this case, if the coating of the 2 separated wires contains an electrolytic substance in advance, conductivity can be obtained at the time of wetting with ultrapure water, and therefore, the liquid 1 as ultrapure water can be detected by the water leakage sensor having the above-described configuration.
Of course, the features of the above embodiments can be combined for use. For example, the optical fiber 80 is laid around the linear motor, and the detector 100 having the prism 101 is disposed on the substrate stage PST (substrate tray PH).
The optical fiber or the prism may not be provided at all of the above positions, and may be provided inside the substrate stage PST or in the vicinity of an actuator such as a photodetector or a piezoelectric element, if necessary.
As shown in fig. 8 to 10, the optical fiber 80 may be disposed so as to wrap around the substrate stage PST or around the substrate base plate 41, but it is needless to say that the 1 st optical fiber 80C may be provided around the substrate stage PST and the 2 nd optical fiber 80D may be provided around the substrate base plate 41 as shown in the side view of fig. 19 (b). The optical fiber 80(80E) may be disposed inside the recovery port 61 provided in the substrate stage PST. As in the above embodiment, in fig. 19, the substrate stage PST includes the auxiliary plate 43 formed to surround the periphery of the substrate P held on the substrate tray PH and the recovery port 61 provided outside thereof. The auxiliary plate 43 has a flat surface (flat portion) 43A provided around the substrate P held on the substrate tray PH and having substantially the same plane as the surface of the substrate P. The flat surface 43A is formed in a ring shape so as to surround the periphery of the substrate P. Further, a recovery port 61 is provided on the outer side of the auxiliary plate 43 (flat surface 43A). The recovery port 61 is an annular groove formed so as to surround the auxiliary plate 43 (substrate P). In the present embodiment, the liquid absorbing member (62) is not disposed inside the recovery port 61. As shown in the plan view of fig. 19(a), the optical fiber 80E is arranged along the entire circumference of the recovery port 61 formed in a ring shape. An optical fiber 80E for detecting the presence or absence of the liquid 1 is provided inside the recovery port 61, so that even if the liquid 1 leaks from the substrate P, the leaked liquid 1 can be detected by the optical fiber 80E before the leaked liquid 1 diffuses. Therefore, when the optical fiber 80E detects the presence of the liquid 1, the controller CONT takes appropriate measures such as stopping the liquid supply operation of the liquid supply mechanism 10 using the valve 13, thereby preventing the liquid 1 from spreading or leaking from the substrate stage PST. When the optical fiber 80E is disposed inside the recovery port 61, the liquid absorbing member (62) may be disposed in the recovery port 61.
As shown in fig. 19(b), when the optical fibers 80 for detecting the presence or absence of the liquid 1 are provided at a plurality of predetermined positions of the exposure apparatus EX (substrate stage PST), the control apparatus CONT controls the operation of the exposure apparatus EX in accordance with the detection results of the plurality of optical fibers 80. For example, the control device CONT selects an operation of at least one of stopping the supply of the liquid by the liquid supply mechanism 10 and stopping the supply of the power to the electrical device, in accordance with the position of the optical fiber 80 that detects the liquid 1 among the plurality of optical fibers 80.
Specifically, the controller CONT stops the liquid supply operation of the liquid supply mechanism 10 when the 1 st optical fiber 80C provided in the substrate stage PST detects the presence of the liquid 1, and stops the power supply to the predetermined electrical device when the 2 nd optical fiber 80D provided in the substrate base plate 41 detects the presence of the liquid 1. Here, the predetermined electric devices include linear motors 47 and 48 for driving the substrate stage PST, and a vibration isolation unit 9 for supporting the substrate base plate 41 in a vibration isolation manner.
When the 1 st optical fiber 80C provided on the substrate stage PST detects the presence of the liquid 1 and the 2 nd optical fiber 80D provided on the substrate base plate 41 does not detect the presence of the liquid 1, the control device CONT judges that the leaked liquid 1 does not reach the linear motors 47 and 48 or the vibration isolation unit 9 that drives the substrate stage PST. That is, the control unit CONT determines that the spread range of the leaked liquid 1 is a narrow range. In this case, the controller CONT stops the liquid supply operation of the liquid supply mechanism 10, but continues supplying the electric power to the linear motors 47 and 48 or the vibration isolation unit 9. On the other hand, when the 2 nd optical fiber 80D provided on the substrate base plate 41 detects the presence of the liquid 1, the control device CONT judges that the leaked liquid 1 has spread to the linear motors 47 and 48 or the vibration isolation unit 9. That is, the control unit CONT determines that the spread range of the leaked liquid 1 is a wide range. In this case, the controller CONT stops the liquid supply operation of the liquid supply mechanism 10 and at the same time stops the power supply to at least one of the linear motors 47 and 48 and the vibration isolation unit 9. When the 2 nd optical fiber 80D detects the presence of the liquid 1, the controller CONT preferably stops the supply of power to the linear motors 47 and 48 or the vibration isolation unit 9, but does not stop the supply of power to the entire exposure apparatus EX. When the power supply to the entire exposure apparatus EX is stopped, a long time is required for the subsequent recovery operation and stabilization.
In this way, since the operation of the exposure apparatus EX is controlled in accordance with the detection results of the 1 st optical fiber 80C and the 2 nd optical fiber 80D provided at different positions from each other, appropriate measures or countermeasures can be taken in accordance with the diffusion range of the leaked liquid 1. Therefore, the time required for the recovery operation after the occurrence of the leakage of the liquid 1 can be shortened, and the lowering of the motion rate of the exposure apparatus EX can be prevented. When the 1 st optical fiber 80C provided in the substrate stage PST detects the presence of the liquid 1, the control unit CONT stops the supply of the liquid by the liquid supply mechanism 10 and continues the supply of the electric power to the electric device, thereby minimizing the time required for the recovery operation or stabilization. On the other hand, when the 2 nd optical fiber 80D provided on the substrate base plate 41 detects the presence of the liquid 1, the control device CONT stops the supply of power to the linear motors 47 and 48 driving the substrate stage PST or the vibration prevention unit 9. Thus, even if the liquid leaked in a wide range spreads, it is possible to prevent the occurrence of damage such as electric leakage or malfunction.
The controller CONT may control the operation of the exposure apparatus EX in accordance with the amount of the liquid 1 detected by the optical fiber 80. For example, the control unit CONT selects at least one of the stop of the liquid supply operation of the liquid supply mechanism 10 and the stop of the power supply to the electrical device, in accordance with the amount of the liquid 1 detected by the optical fiber 80.
Specifically, the controller CONT stops the liquid supply operation of the liquid supply mechanism 10 when the liquid 1 in an amount equal to or larger than the preset 1 st reference value is detected by at least one of the 1 st optical fiber 80C and the 2 nd optical fiber 80D, and stops the power supply to the electric devices such as the linear motors 47 and 48 that drive the substrate stage PST and the vibration isolation unit 9 that supports the substrate base plate 41 in a vibration isolation manner when the liquid 1 in an amount equal to or larger than the 2 nd reference value is detected. Here, the 2 nd reference value is a value larger than the 1 st reference value.
The controller CONT determines that the amount of the liquid 1 leaked is small when determining that the amount of the liquid 1 detected by at least one of the 1 st optical fiber 80C and the 2 nd optical fiber 80D is equal to or larger than the 1 st reference value and smaller than the 2 nd reference value. In this case, the controller CONT stops the liquid supply operation of the liquid supply mechanism 10 and continues the power supply to the linear motors 47 and 48 and the vibration isolation unit 9. On the other hand, when determining that the amount of the liquid 1 detected by at least one of the 1 st optical fiber 80C and the 2 nd optical fiber 80D is equal to or greater than the 2 nd reference value, the control device CONT determines that the amount of the leaked liquid 1 is large. In this case, the controller CONT stops the liquid supply operation of the liquid supply mechanism 10 and stops the supply of power to at least one of the linear motors 47 and 48 and the vibration isolation unit 9. When the optical fibers 80C and 80D detect the liquid 1 in an amount equal to or larger than the 2 nd reference value, the control device CONT preferably stops the supply of power to the linear motors 47 and 48 or the vibration isolation unit 9, but does not stop the supply of power to the entire exposure apparatus EX. This is because, when the power supply to the entire exposure apparatus EX is stopped, a long time is required for the subsequent recovery work and stabilization.
In this way, the operation of the exposure apparatus EX can be controlled in accordance with the amount of the liquid 1 detected by the optical fiber 80, and in this case, appropriate measures can be taken in accordance with the amount of the leaked liquid 1. Therefore, the time required for the recovery operation after the occurrence of the leakage of the liquid 1 can be shortened, and the decrease in the operation rate of the exposure apparatus EX can be prevented.
In the above embodiment, 1 optical fiber 80 is arranged so as to surround the substrate stage PST and the substrate base plate 41, but a plurality of optical fibers may surround the substrate stage PST and the substrate base plate 41. For example, 1 optical fiber 80 may be disposed on each of 4 sides of the substrate base 41, and the periphery of the substrate base 41 may be surrounded by a total of 4 optical fibers 80. Thus, when the liquid 1 is detected by 1 optical fiber, the leakage position of the liquid 1 can be easily determined by examining which optical fiber reacts.
Further, as described above, when the positional relationship between the projection optical system PL and the substrate stage PST becomes abnormal, or the like, the liquid 1 cannot be held under the projection optical system PL, and a problem occurs in that the liquid 1 leaks. Therefore, in order to prevent the leakage of the liquid 1, the movement range of the substrate stage PST may be limited. This will be explained with reference to fig. 20.
In fig. 20, the substrate stage PST has a1 st area LA1 as a flat area, and the 1 st area LA1 includes the surface of the substrate P (or dummy substrate DP) held on the substrate tray PH and the flat surface 43A of the auxiliary plate 43 on the same plane as the surface of the substrate P. In addition, a2 nd region LA2 which is a flat region is provided at a position facing the 1 st region LA1, and the 2 nd region LA2 includes the image plane side front end surface (lower surface) 2a of the projection optical system PL and a part of the lower surface of the plate member 2P which is on the same plane as the lower surface 2 a. Here, the liquid 1 is held between the 1 st flat surface and the 2 nd flat surface on the substrate stage PST, and the liquid immersion area AR2 is formed, the 2 nd flat surface including the front end surface 2a of the projection optical system PL and facing the 1 st flat surface. Therefore, the 1 st area LA1 of the substrate stage PST and the 2 nd area LA2 facing the 1 st area LA1 and including the distal end surface 2a of the projection optical system PL are areas capable of holding liquid. The liquid 1 is held between a part of the 1 st area LA1 and the 2 nd area LA2, and forms a liquid immersion area AR 2. The 1 st area LA1 and the 2 nd area LA2 do not necessarily have to be flat surfaces, and may have curved surfaces or concave-convex surfaces if the liquid 1 can be held.
In the present embodiment, the liquid 1 in the liquid immersion area AR2 also comes into contact with the supply nozzle 14 having the liquid supply port 14K and a part of the recovery nozzle 21 having the liquid recovery port 21K, which are disposed around the optical element 2 at the distal end portion of the projection optical system PL. That is, the 2 nd area LA2 capable of holding the liquid 1 is configured to include the liquid contact surface of the supply nozzle 14 and the recovery nozzle 21.
In the present embodiment, the control device CONT restricts the movement of the substrate stage PST in accordance with the positional relationship between the 1 st area LA1 and the 2 nd area LA 2. Specifically, as shown in fig. 20(a), when the liquid 1 is held between the 1 st area LA1 and the 2 nd area LA2, the liquid 1 can be held in the positional relationship between the 1 st area LA1 and the 2 nd area LA2 as shown in fig. 20 (b). However, when the substrate stage PST is moved in the + X direction from the positional relationship shown in fig. 20(b), a part of the liquid immersion area AR2 extends outside the 1 st area LA1, and the liquid 1 cannot be held between the 1 st area LA1 and the 2 nd area LA 2. At this time, the controller CONT judges that an abnormality has occurred in the positional relationship between the 1 st area LA1 and the 2 nd area LA2, and restricts the movement of the substrate stage PST. Specifically, the control device CONT stops the movement of the substrate stage PST. Thus, problems such as outflow of the liquid 1 can be prevented.
Here, the control device CONT determines whether or not an abnormality occurs in the positional relationship between the 1 st area LA1 and the 2 nd area LA2 based on the measurement result of the laser interferometer 46. The controller CONT detects the XY-directional position of the substrate stage PST by the laser interferometer 46, and obtains the positional relationship between the 1 st region LA1 and the 2 nd region LA2, which is the positional information of the 1 st region LA1 with respect to the 2 nd region LA2, from the position detection result. Information on the sizes of the 1 st area LA1 and the 2 nd area LA2 is stored in the control apparatus CONT in advance. Information on the size of the liquid immersion area AR2 formed between the 1 st area LA1 and the 2 nd area LA2 is also obtained in advance by, for example, experiments or simulations, and stored in the control device CONT. The controller CONT obtains in advance an abnormal value regarding the positional relationship between the 1 st area LA1 and the 2 nd area LA2, and stores the abnormal value in the controller CONT. Here, the abnormal value is a value (relative distance) that is a positional relationship between the 1 st area LA1 and the 2 nd area LA2, and when the 1 st area LA1 exceeds the abnormal value with respect to the 2 nd area LA2, the liquid 1 cannot be held between the 1 st area LA1 and the 2 nd area LA 2.
The control device CONT restricts (stops) the movement of the substrate stage PST when the position of the 1 st region LA1 with respect to the 2 nd region LA2 exceeds the abnormal value based on the measurement result of the laser interferometer 46. Thus, problems such as outflow of the liquid 1 can be prevented.
Further, the control device CONT may change the moving direction of the substrate stage PST without stopping the movement of the substrate stage PST when the position of the 1 st region LA1 with respect to the 2 nd region LA2 exceeds the abnormal value based on the measurement result of the laser interferometer 46. Specifically, in fig. 20, when the substrate stage PST moves in the + X direction and the 2 nd area LA2 has an abnormal positional relationship with respect to the 1 st area LA1, the controller CONT moves the substrate stage PST in the-X direction, for example. In this way, problems such as outflow of the liquid 1 can also be prevented.
The controller CONT may be configured to limit the operation of the liquid supply mechanism (10) when an abnormality occurs in the positional relationship between the 1 st area LA1 and the 2 nd area LA2 and the position of the 1 st area LA1 relative to the 2 nd area LA2 exceeds the above-mentioned abnormal value. Specifically, the controller CONT stops the liquid supply operation by the liquid supply mechanism (10) when an abnormality occurs in the positional relationship between the 1 st area LA1 and the 2 nd area LA 2. Thus, problems such as outflow of the liquid 1 can be prevented. Alternatively, when the 2 nd area LA2 is in an abnormal positional relationship with respect to the 1 st area LA1, the control device CONT lowers the liquid supply amount (liquid supply amount per unit time) of the liquid supply mechanism (10). Alternatively, the control device CONT may be configured to stop the supply of power to the linear motors (47, 48) or the vibration isolation device (9) or stop the suction from the suction port (42A) when an abnormality occurs in the positional relationship between the area 1 LA1 and the area 2 LA 2.
On the other hand, for example, after the liquid immersion exposure of the substrate P is completed, the supply of the liquid by the liquid supply mechanism (10) is stopped, and after the liquid 1 on the substrate P (substrate stage PST) is collected by the liquid collection mechanism (20), the liquid 1 is not held between the 1 st area LA1 and the 2 nd area LA 2. In this case, the control unit CONT releases the movement restriction of the substrate stage PST. That is, the controller CONT limits the movement range of the substrate stage PST to the 1 st range in which the liquid 1 can be held between the 1 st area LA1 and the 2 nd area LA2 while the liquid 1 is supplied by the liquid supply mechanism (10), and limits the movement range to the 2 nd range wider than the 1 st range while the liquid supply mechanism (10) stops supplying the liquid 1. That is, the control device CONT restricts the movement range of the substrate stage PST to the 1 st range when the liquid 1 is held between the projection optical system PL and the substrate stage PST (substrate P), and allows the movement of the substrate stage PST within the 2 nd range wider than the 1 st range when the liquid 1 is not held between the projection optical system PL and the substrate stage PST (substrate P). Thus, for example, during exposure of the substrate P, the liquid 1 can be held between the projection optical system PL and the substrate stage PST (substrate P) satisfactorily, and, for example, a predetermined operation such as an operation of moving the substrate stage PST to a loading/unloading position of the substrate P, which is a subsequent operation, can be performed smoothly.
Fig. 21 is a view showing another embodiment of the present invention, fig. 21(a) is a side view, and fig. 21(b) is a plan view of the substrate stage as viewed from above. In fig. 21(a), a nozzle member 18 having a liquid supply port 14K and a liquid recovery port 21K is provided around the optical element 2 of the projection optical system PL. In the present embodiment, the nozzle member 18 is an annular member provided above the substrate P (substrate stage PST) so as to surround the side surface of the optical element 2. A gap is provided between the nozzle member 18 and the optical element 2, and the nozzle member 18 is supported by a predetermined support mechanism so as to be isolated from vibration of the optical element 2.
The nozzle member 18 is provided above the substrate P (substrate stage PST), and has a liquid supply port 14K disposed to face the surface of the substrate P. In the present embodiment, the nozzle member 18 has 2 liquid supply ports 14K. The liquid supply port 14K is provided on the lower surface 18a of the nozzle member 18.
The nozzle member 18 is provided above the substrate P (substrate stage PST), and has a liquid recovery port 21K disposed to face the surface of the substrate P. In the present embodiment, the nozzle member 18 has 2 liquid recovery ports 21K. The liquid recovery port 21K is provided on the lower surface 18a of the nozzle member 18.
The liquid supply ports 14K and 14K are provided at respective positions on both sides in the X-axis direction of the projection area AR1 of the projection optical system PL, and the liquid recovery ports 21K and 21K are provided outside the projection area AR1 of the projection optical system PL with respect to the liquid supply ports 14K and 14K. The projection area AR1 of the projection optical system PL of the present embodiment is set to a rectangular shape in plan view with the Y-axis direction as the vertical direction and the X-axis direction as the horizontal direction.
The lower surface (surface facing the substrate P) 18a of the nozzle member 18 is a substantially flat surface, the lower surface (liquid contact surface) 2a of the optical element 2 is also a flat surface, and the lower surface 18a of the nozzle member 18 is substantially flush with the lower surface 2a of the optical element 2. Thus, the liquid immersion area AR2 can be formed well in a wide range. The 2 nd area LA2 capable of holding the liquid 1 is an area inside the recovery port 21K in the lower surface 2a of the optical element 2 and the lower surface 18a of the nozzle member 18.
The substrate stage PST is provided with a recess 55, and the substrate tray PH is disposed in the recess 55. The upper surface 57 of the substrate table PST other than the concave portion 55 is a flat surface (flat portion) having substantially the same height (same plane) as the surface of the substrate P held on the substrate tray PH. The 1 st area LA1 capable of holding the liquid 1 is an area including the surface and the upper surface 57 of the substrate P.
As shown in fig. 21(b), the moving mirrors 45 are disposed at 2 edge portions perpendicular to each other of the substrate stage PST having a rectangular shape in a plan view. Further, on the substrate stage PST, the reference member 300 is disposed at a predetermined position outside the substrate P. The reference member 300 is provided with a reference mark PFM detected by a substrate alignment system not shown in the figure and a reference mark MFM detected by a mask alignment system in a predetermined positional relationship. In the substrate alignment system of the present embodiment, for example, an FIA (field image alignment) system is used as disclosed in japanese patent application laid-open No. 4-65603, in which the substrate stage PST is made stationary, illuminating light such as white light from a halogen lamp is irradiated onto a mark, an image of the obtained mark is picked up by an image pickup device within a predetermined image pickup field, and the position of the mark is measured by image processing. In the mark alignment system of the present embodiment, a VRA (visual reticle alignment) system, which irradiates light to a mark, performs image processing on mark image data obtained by imaging with a CCD camera or the like, and detects a mark position, such as that disclosed in japanese patent application laid-open No. 7-176468, is used. The upper surface 301A of the reference member 300 is a substantially flat surface and is provided at substantially the same height (flush) as the surface of the substrate P held on the substrate stage PST and the upper surface 57 of the substrate stage PST. The upper surface 301A of the reference member 300 may function as a reference surface for the focus detection system 56.
In addition, the substrate alignment detects alignment marks AM formed on the substrate P. As shown in fig. 21(b), a plurality of exposure regions S1 to S24 are formed on the substrate P, and a plurality of alignment marks AM are provided on the substrate P corresponding to the plurality of exposure regions S1 to S24.
Further, an uneven illuminance sensor 400, such as that disclosed in japanese patent laid-open No. 57-117238, is disposed as a measurement sensor at a predetermined position on the substrate stage PST outside the substrate P. The uneven illuminance sensor 400 has an upper plate 401 having a rectangular shape in a plan view. The upper surface 401A of the upper plate 401 is a substantially flat surface and is provided at substantially the same height (flush) with the surface of the substrate P held by the substrate stage PST and the upper surface 57 of the substrate stage PST. A pinhole portion 470 permeable to light is provided on the upper face 401A of the upper plate 401. The pinhole 470 in the upper surface 401A is covered with a light-shielding material such as chromium.
Further, an aerial image measuring sensor 500 such as that disclosed in, for example, japanese patent application laid-open No. 2002-14005 is provided as a measuring sensor at a predetermined position outside the substrate P on the substrate stage PST. The aerial image measurement sensor 500 has an upper plate 501 having a rectangular shape in a plan view. The upper surface 501A of the upper plate 501 is formed into a substantially flat surface and is provided at substantially the same height (flush with) the surface of the substrate P held on the substrate stage PST and the upper surface 57 of the substrate stage PST. The upper face 501A of the upper plate 501 is provided with a slit portion 570 through which light can pass. The slit portion 570 in the upper surface 501A is covered with a shielding material such as chromium.
Further, an irradiation amount sensor (illuminance sensor) 600 such as that disclosed in japanese patent application laid-open No. 11-16816 is provided on the substrate stage PST, and an upper surface 601A of an upper plate 601 of the irradiation amount sensor 600 is provided at substantially the same height (flush surface) as the surface of the substrate P held on the substrate stage PST or the upper surface 57 of the substrate stage PST.
Further, a conduit member 89 is provided on a side surface of the substrate stage PST so as to surround the substrate stage PST. The water conduit member 89 can collect (hold) the liquid 1 leaked from the substrate P or the substrate stage PST, and is provided outside the upper surface (flat surface) 57 of the substrate stage PST. Further, an optical fiber 80 that can detect the presence or absence of the liquid 1 is disposed inside the conduit member 89. When the optical fiber 80 of the conduit member 89 detects the presence of the liquid 1, the control device CONT takes appropriate measures such as stopping the liquid supply operation of the liquid supply mechanism (10) in the same manner as in the above embodiment.
In the present embodiment, the liquid immersion area AR2 is formed on the substrate P when the substrate P is exposed, and the liquid immersion area AR2 is formed on the upper plates 301, 401, 501, and 601 when the measurement process is performed using the sensors 400, 500, and 600 when, for example, the reference mark MFM of the reference member 300 is measured. Then, a measurement process through the liquid 1 is performed. For example, when the reference mark MFM on, for example, the reference member 300 is measured by the liquid 1, the region including the upper face 301A of the reference member 300 in the 1 st region LA1 is opposed to the 2 nd region LA2, and the space between a part of the 1 st region LA1 and the 2 nd region LA2 is filled with the liquid 1. When the measurement process with the uneven illuminance sensor 400 using the liquid 1 is performed, the region including the upper surface 401A of the upper plate 401 in the 1 st region LA1 faces the 2 nd region LA2, and the space between a part of the 1 st region LA1 and the 2 nd region LA2 is filled with the liquid 1. Similarly, when the measurement processing by the liquid 1 is performed using the sensors 500 and 600, the region including the upper surfaces 501A and 601A of the upper plates 501 and 601 in the 1 st region LA1 faces the 2 nd region LA2, and the space between a part of the 1 st region LA1 and the 2 nd region LA2 is filled with the liquid 1.
While the liquid 1 is supplied by the liquid supply mechanism (10) in order to form the liquid immersion area AR2 on the substrate stage PST (on the 1 st area LA1), the control apparatus CONT restricts the movement range of the substrate stage PST to the 1 st range SR1 shown in fig. 21 (b). In fig. 21(b), a symbol LA2a shows a position when the 2 nd region LA2 is arranged to the most + Y side and the most-X side in the 1 st region LA1 in a range where the liquid 1 can be held. In fig. 21b, for simplicity of explanation, the case where the optical axis AX (the 2 nd area LA2) of the projection optical system PL moves relative to the substrate stage PST (the 1 st area LA1) will be described. Also, symbol LA2b shows the position when the 2 nd area LA2 is arranged to the most + Y side and the most + X side in the 1 st area LA 1. The 2 nd area LA2c shows positions when the 2 nd area LA2 is disposed to the most-Y side and the most + X side in the 1 st area LA 1. Symbol LA2d shows the position when the 2 nd area LA2 is disposed to the most-Y side and the most-X side in the 1 st area LA 1.
A region connecting the centers of the respective 2 nd regions LA2a to LA2d (here, the optical axis AX of the projection optical system PL) is the 1 st range SR 1. In this way, by limiting the movement range of the substrate stage PST to the 1 st range SR1 while the liquid 1 is supplied by the liquid supply mechanism (10), the liquid 1 can be constantly held between the 1 st region LA1 and the 2 nd region LA2, and problems such as leakage of the liquid 1 can be prevented.
On the other hand, while the liquid 1 is not supplied from the liquid supply mechanism (10), the control device CONT limits the movement range of the substrate stage PST to a2 nd range SR2 wider than the 1 st range SR 1. Here, the 1 st range SR1 is included in the 2 nd range SR 2. In this way, while the liquid supply mechanism (10) stops supplying the liquid 1, the movement of the substrate table PST to the loading/unloading position of the substrate P can be smoothly performed by limiting the liquid supply mechanism to the 2 nd range SR2 wider than the 1 st range SR 1.
While the embodiments of the present invention have been described above in detail, in the present invention, when an abnormality is detected by a control device provided in an exposure apparatus, the control device controls an appropriate mechanism or device of the exposure apparatus to prevent leakage, suction of water leakage, and the like due to water leakage and the like in advance. Here, the block diagram of fig. 23 collectively shows the relationship among the detection portion where an abnormality is detected, the control device, and the controlled portion controlled by the control device. The control device of the exposure apparatus is connected to various detection devices provided inside the exposure apparatus, such as a supply-side/recovery-side flow meter which detects an abnormality (liquid flow) based on a flow rate difference or a single flow rate difference between the supply-side flow meter and the recovery-side flow meter, a stage interferometer which measures a stage position of the substrate stage to detect a stage position abnormality (thereby causing a water leak), a focus detection system which detects a focus state of the substrate stage and detects a stage position abnormality (thereby causing a water leak), leak detectors 700 and 701 which detect a water leak (abnormality) attached to an optical fiber or a prism provided on the substrate stage or a base plate, and a water level meter which detects an abnormality of a recovery amount based on a water level of the recovery tank. The control device may receive the abnormality signal from the detection systems. In this case, the control device compares a predetermined reference signal with the signals received from the respective detectors, and can determine whether the signals are normal or abnormal.
The control device of the exposure apparatus is also connected to various devices related to the outside of the exposure apparatus, for example, a liquid (pure water) manufacturing apparatus, a liquid (pure water) temperature adjusting apparatus, a developing apparatus, a substrate transfer apparatus, and the like, and can receive signals notifying abnormality of these devices. The control device of the exposure device may further receive a signal notifying an abnormality in a plant in which the exposure device is installed. Examples of the abnormality of a plant or the like in which the exposure apparatus is installed include an abnormality of a clean room in which the exposure apparatus is disposed, an abnormality of the capacity of pure water, electric power, or the like supplied to the exposure apparatus, an earthquake, a fire, or the like. The control device may compare a predetermined reference signal with the signals received from the respective correlation devices, and determine whether the signals are normal signals or abnormal signals.
The control device of the exposure apparatus may be connected to various components of the controlled apparatus, such as the liquid supply mechanism, the liquid recovery mechanism, and the stage device, particularly, sensors such as a stage air bearing, a stage linear motor, a substrate tray suction system, and a photomultiplier tube (フオトマル), a vibration isolation unit, and an actuator, as described in the above embodiments, and may receive a signal for notifying abnormality of each component. In addition, in the absence of sensors for detecting earthquakes,
the control device may also receive an anomaly signal from the seismic sensor. In the case where a water quality sensor for measuring the quality (temperature, dissolved oxygen concentration, and proportion of impurities such as organic substances) of the liquid 1 is provided, an abnormality signal may be received from the water quality.
Next, the control operation of the control device will be briefly described with reference to fig. 24. The control device receives a signal indicating an abnormality from a detection system inside the exposure device or related devices 1 to 4 outside the exposure device. The signal indicating the abnormality is, for example, a signal that affects the flow of the liquid supplied (and further recovered) for the liquid immersion exposure. In this case, the control device may compare the received signal with the reference signal and determine that the received signal is an abnormal signal. Then, the control device identifies a portion where the abnormality occurs based on the abnormality signal. In this case, the control device may also be configured to issue an alarm from the alarm device. Then, the control device determines which device should be controlled according to the portion where the abnormality occurs, and sends a control signal to the device to take measures against the abnormal situation. For example, when a liquid leak is detected by a leak detector (optical fiber or the like) provided on the substrate table, the control device stops the supply of the liquid to the liquid supply mechanism, the movement of the table by the table control system, the suction by the table air bearing and the substrate tray suction system, and the supply of the power to the table linear motor, the substrate tray suction system, the sensor, the vibration prevention unit, and the actuator, respectively, in response to the detection signal, while only the liquid recovery by the liquid recovery mechanism can be continued. The controller determines which device stops its operation based on the location and the degree of the liquid leakage (the magnitude of the signal). Depending on the magnitude of the detection signal, the electric device such as the stage linear motor or the sensor is continuously operated, and only the operation of the liquid supply mechanism can be stopped.
As described above, pure water is used for the liquid 1 of the present embodiment. Pure water is easily available in large quantities in semiconductor manufacturing plants and the like, and has the advantage of not adversely affecting the photoresist and optical elements (lenses) and the like on the substrate P. Further, pure water has little adverse effect on the environment and has an extremely low impurity content, and therefore, has a function of cleaning the surface of the substrate P and the surface of the optical element provided on the distal end surface of the projection optical system PL.
Further, since pure water (water) has a refractive index n of substantially 1.44 with respect to the exposure light EL having a wavelength of about 193nm, when ArF excimer laser light (having a wavelength of 193nm) is used as a light source of the exposure light EL, the wavelength of the light on the substrate P is reduced to 1/n, that is, about 134nm, and high resolution can be obtained. Further, since the depth of focus is increased by about n times, that is, about 1.44 times, as compared with the depth of focus in air, if the depth of focus is secured to the same extent as that in the case of use in air, the numerical aperture of the projection optical system PL can be further increased, thereby also improving the resolution.
In the present embodiment, the optical element 2 is attached to the tip of the projection optical system PL, but the optical element attached to the tip of the projection optical system PL may be an optical plate for adjusting optical characteristics of the projection optical system PL, such as aberration (spherical aberration, coma aberration, etc.), or a parallel plane plate that transmits the exposure light EL. Further, since the optical element in contact with the liquid 1 is a parallel plate which is cheaper than a lens, even if a substance (for example, a silicon-based organic substance or the like) which causes a decrease in the transmittance of the projection optical system PL, the illuminance of the exposure light EL on the substrate P, and the uniformity of the illuminance distribution adheres to the parallel plate at the time of conveyance, assembly, adjustment, or the like of the exposure apparatus EX, the parallel plate only needs to be replaced immediately before the liquid 1 is supplied, and there is an advantage in that the cost is reduced compared to the case where the optical element in contact with the liquid 1 is a lens. That is, since the surface of the optical element in contact with the liquid 1 is contaminated by scattered particles generated from the resist by irradiation with the exposure light EL, adhesion of impurities in the liquid 1, or the like, it is necessary to replace the optical element periodically, but by using the optical element as an inexpensive parallel flat plate, the cost of replacing parts is lower than that of a lens, the time required for replacement can be shortened, and an increase in maintenance cost (running cost) and a decrease in processing energy can be suppressed.
The liquid 1 in the present embodiment is water, but may be a liquid other than water, and for example, the light source of the exposure light EL is F2In the case of laser, F is caused2Since laser light is not permeable to water, a transmissive F can be used as the liquid 1 in this case2Examples of the laser include fluorine-based liquids such as fluorine-based oils and perfluorinated polyesters (PFPE). As the liquid 1, a liquid (for example, cedar oil) which has a high transmittance to the exposure light EL and a refractive index as high as possible and is stable with respect to the projection optical system PL and the resist applied to the surface of the substrate P can be used.
In each of the above embodiments, the shape of the nozzle is not particularly limited, and for example, the liquid 1 may be supplied or collected from the nozzle by the tube 2 with respect to the long side of the projection area AR 1. In this case, since the supply and recovery of the liquid 1 can be performed from both the + X direction and the-X direction, the supply nozzle and the recovery nozzle may be arranged vertically.
The substrate P of each of the above embodiments can be applied not only to a semiconductor wafer for manufacturing a semiconductor device, but also to a glass substrate for a display device, a ceramic wafer for a thin film magnetic head, a mask used in an exposure apparatus, a reticle original plate (synthetic quartz, silicon wafer), or the like.
In addition, in the above embodiments, the exposure apparatus in which the space between the projection optical system PL and the substrate P is partially filled with the liquid is employed, but the present invention is also applicable to a liquid immersion exposure apparatus in which a stage holding a substrate to be exposed in a liquid tank is moved, or a liquid immersion exposure apparatus in which a liquid tank having a predetermined depth is formed on the stage and a substrate is held therein. The structure and exposure operation of a liquid immersion exposure apparatus for moving a stage holding a substrate to be exposed in a liquid bath are described in detail in, for example, japanese patent application laid-open No. 6-124873, and the structure and exposure operation of a liquid immersion exposure apparatus for holding a substrate in a liquid bath formed in a liquid bath at a predetermined depth are described in detail in, for example, japanese patent laid-open No. 10-303114 or us patent 5,825,043, and the contents of the descriptions of these documents are incorporated as a part of the description herein as long as the statutory approval of the country specified or selected by the present international application is allowed.
The exposure apparatus EX is applicable to not only a step-and-scan type exposure apparatus (step-and-scan exposure apparatus) of a step-and-scan type which synchronously moves the mask M and the substrate P and performs scanning exposure of the pattern of the mask M, but also a step-and-repeat type projection exposure apparatus (step-and-repeat apparatus) which performs exposure of the pattern of the mask M together with the substrate P being stationary and sequentially moves the substrate P in steps. The present invention is also applicable to a step-and-stitch type exposure apparatus that transfers a pattern by partially overlapping at least 2 patterns on a substrate P.
The present invention is also applicable to a two-stage exposure apparatus having 2 stages on which substrates to be processed such as wafers can be placed and which can be independently moved in the XY direction. The structure and exposure operation of the two-stage type exposure apparatus are disclosed in, for example, japanese patent laid-open nos. 10-163099 and 10-214783 (corresponding to U.S. Pat. nos. 6,341,007, 6,400,441, 6,549,269 and 6,590,634), japanese patent laid-open No. 2000-505958 (corresponding to U.S. Pat. No. 5,969,441) or U.S. Pat. No. 6,208,407, and the contents of the documents are cited as a part of the description herein as long as the statutes of the country designated or selected by the present international application are allowed.
As disclosed in japanese patent application laid-open No. 11-135400, the present invention is applicable to an exposure apparatus having a substrate stage that holds a substrate P and a measurement stage having various measurement members, sensors, and the like. In this case, the liquid can be held between the projection optical system and the upper surface of the measurement table, and the measurement table can be provided with the water leak detector or the like.
The type of exposure apparatus EX is not limited to an exposure apparatus for semiconductor manufacturing that exposes a semiconductor device pattern onto a substrate P, and is widely applicable to an exposure apparatus for manufacturing a liquid crystal display device or a display, an exposure apparatus for manufacturing a thin film magnetic head, an image pickup device (CCD), a reticle, a mask, or the like.
When the substrate stage PST or the mask stage MST uses a linear motor, either an air levitation type using an air bearing or a magnetic levitation type using a lorentz force or a reactance force can be used. Each of the PSTs and MSTs may be of a type that moves along a guide member, or may be of a type that does not include a guide member. Examples of the use of linear motors in the stations are disclosed in U.S. patent nos. 5,623,853 and 5,528,118, the contents of which are incorporated by reference herein as if permitted by the statutes of the countries specified or selected in the international application.
As a driving mechanism for each of the PST and MST, a planar motor may be used in which a magnet unit having a magnet arranged in 2 dimensions and an armature unit having a coil arranged in 2 dimensions are opposed to each other, and each of the PST and MST is driven by an electromagnetic force. In this case, either one of the magnet unit and the armature unit may be connected to the tables PST and MST, and the other of the magnet unit and the armature unit may be provided on the movable surface side of the tables PST and MST.
The reaction force generated by the movement of the substrate stage PST may mechanically escape to the floor (ground) using the frame member without being transmitted to the projection optical system PL. The method of processing the reaction force is disclosed in detail in, for example, U.S. Pat. No. 5,528,118 (japanese patent application laid-open No. 8-166475), and the contents of the documents are incorporated herein by reference as long as the statutes of the country specified or selected in the international application are allowable.
The reaction force generated by the movement of the substrate stage PST may mechanically escape to the floor (ground) using the frame member without being transmitted to the projection optical system PL. The method of processing the reaction force is disclosed in detail in, for example, U.S. Pat. No. 5,874,820 (japanese patent application laid-open No. 8-330224), and the contents of the documents are incorporated herein by reference as if the statute of the country specified or selected in the international application is allowable.
The exposure apparatus EX according to the embodiment of the present application is manufactured by assembling various subsystems including the respective components recited in the claims of the present application while maintaining predetermined mechanical accuracy, electrical accuracy, and optical accuracy. In order to ensure these various accuracies, before and after the assembly, adjustment for achieving optical accuracy is performed on various optical systems, adjustment for achieving mechanical accuracy is performed on various mechanical systems, and adjustment for achieving electrical accuracy is performed on various electrical systems. The assembly process from the various subsystems to the exposure apparatus includes mechanical connection of the various subsystems, wiring connection of circuits, piping connection of air pressure circuits, and the like. Before the assembly process of the exposure apparatus from the various subsystems, there is naturally an assembly process of each subsystem. When the assembling process of the various subsystems in the exposure apparatus is completed, the various subsystems are comprehensively adjusted to ensure various accuracies of the entire exposure apparatus. The exposure apparatus is preferably manufactured in a clean room in which temperature, cleanliness, and the like are controlled.
As shown in fig. 12, a microdevice such as a semiconductor device is manufactured through a step 201 of designing the function and performance of the microdevice, a step 202 of manufacturing a mask based on the design step, a step 203 of manufacturing a substrate as a base material of the device, an exposure processing step 204 of exposing a pattern of the mask to the substrate by the exposure apparatus EX of the above embodiment, a device assembling step (including a dicing step, a bonding step, and a packaging step) 205, a detection step 206, and the like.
Possibility of industrial utilization
According to the present invention, it is possible to detect an abnormality of an internal device or an external related device of an exposure apparatus that affects liquid immersion exposure, and to suppress or reduce an influence of leakage or immersion of an exposure liquid on peripheral devices and members or an exposure operation, and therefore, it is possible to perform liquid immersion exposure processing with high accuracy while maintaining a good state of an expensive exposure apparatus. In this way, a device having desired properties can be manufactured.