Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defects in the prior art, so as to provide a deep ultraviolet dry-wet dual-purpose projection objective and a method.
The projection objective comprises a first protection lens, a second lens group, a diaphragm, a third lens group, a fourth lens group, a fifth lens group and a sixth lens group which are sequentially arranged from an image surface to an object surface along the optical axis direction, wherein the first protection lens is a plane lens and is used for protecting an objective optical system, the replaceable plane lens has no focal power, the thickness of the plane lens is larger than that of the plane lens when the projection objective is in a dry projection state, the second lens group used for converging light beams has positive focal power, the third lens group used for converging light beams has positive focal power, the fourth lens group used for diverging light beams and correcting the defocusing of the objective optical system has negative focal power, and the sixth lens group used for converging light beams has positive focal power.
Further, the thickness of the plane mirror is 35mm when the projection objective is in a dry projection state, and the thickness of the plane mirror is 32mm when the projection objective is in a wet projection state.
Further, the object plane size of the projection objective is 80mm, the image plane size of the projection objective is 20mm, and the multiplying power of the projection objective is-0.25 times.
Further, the image side numerical aperture of the projection objective is 0.56 when the projection objective is in the dry projection state, and the image side numerical aperture of the projection objective is 0.8 when the projection objective is in the wet projection state.
Further, the second lens group includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, which are sequentially arranged from the image surface to the object surface along the optical axis direction, wherein the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all meniscus lenses, the sixth lens and the seventh lens are biconvex lenses, and the meniscus directions of the first lens, the second lens, the third lens, the fourth lens and the fifth lens are all towards the image surface.
Further, the third lens group includes an eighth lens, a ninth lens and a tenth lens which are sequentially arranged from the image surface to the object surface along the optical axis direction, the eighth lens, the ninth lens and the tenth lens are all meniscus lenses, and the meniscus directions of the eighth lens, the ninth lens and the tenth lens are all directed to the object surface.
Further, the fourth lens group includes an eleventh lens, a twelfth lens, and a thirteenth lens, which are each a meniscus lens, disposed in order from the image surface to the object surface in the optical axis direction.
Further, the fifth lens group includes a fourteenth lens, a fifteenth lens and a sixteenth lens which are sequentially arranged from an image surface to an object surface along the optical axis direction, the fourteenth lens and the fifteenth lens are both meniscus lenses, and the sixteenth lens is a plano-convex lens.
Further, the sixth lens group includes a seventeenth lens, an eighteenth lens, a nineteenth lens, a twentieth lens, and a twenty-first lens, which are all meniscus lenses, that are sequentially arranged from the image plane to the object plane in the optical axis direction.
The invention further comprises a deep ultraviolet dry-wet projection method, which is realized based on the deep ultraviolet dry-wet projection objective lens, wherein in a dry projection state, an imaging object is firstly arranged on an object plane, then a light source emits light to sequentially pass through the imaging object, a sixth lens group, a fifth lens group, a fourth lens group, a third lens group, a second lens group and a plane mirror, and finally the imaging object is imaged on an image plane, in a wet projection state, the thickness of the plane mirror is reduced, firstly the imaging object is arranged on the object plane, and then the light source emits light to sequentially pass through the imaging object, the sixth lens group, the fifth lens group, the fourth lens group, the third lens group, the second lens group and the plane mirror, and finally the imaging object is imaged on the image plane.
The technical scheme of the invention has the following advantages:
According to the technical scheme provided by the invention, the thickness of the plane mirror is changed to further realize the switching of the dry imaging and the wet imaging of the projection objective, so that the projection objective is suitable for different environments and different samples, the NA value of the projection objective is increased, the resolution of the objective is improved, the application range of the projection objective is wider, the numerical aperture of the projection objective can be further changed by changing the working modes of the dry imaging and the wet imaging, and the numerical aperture can be changed by changing different immersion liquids in the wet working mode.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of the whole structure of the dry projection objective of the present invention;
FIG. 2 is a graph of the modulation transfer function MTF of the present invention in the dry projection objective state;
FIG. 3 is a diagram of the wavefront phase difference of different fields of view when the present invention is in a dry projection objective state;
FIG. 4 is a graph of field curvature and distortion of a dry projection objective of the present invention;
FIG. 5 is a schematic view of the overall structure of the present invention in a wet projection objective state;
FIG. 6 is a graph of the modulation transfer function MTF of the present invention in a wet projection objective state;
FIG. 7 is a diagram of wavefront phase differences of different fields of view when the present invention is in a wet projection objective state;
Fig. 8 is a graph of curvature of field and distortion in a wet projection objective of the present invention.
Reference numerals illustrate:
1-image plane, 2-plane mirror, 3-first lens, 4-second lens, 5-third lens, 6-fourth lens, 7-fifth lens, 8-sixth lens, 9-seventh lens, 10-diaphragm, 11-eighth lens, 12-ninth lens, 13-tenth lens, 14-eleventh lens, 15-twelfth lens, 16-thirteenth lens, 17-fourteenth lens, 18-fifteenth lens, 19-sixteenth lens, 20-seventeenth lens, 21-eighteenth lens, 22-nineteenth lens, 23-twentieth lens, 24-twenty-first lens, 25-object plane.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or in communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The deep ultraviolet wet and dry dual-purpose projection objective shown in fig. 1 comprises a first protection mirror (part G1 in the figure), a second lens group (part G2 in the figure), a diaphragm 10, a third lens group (part G3 in the figure), a fourth lens group (part G4 in the figure), a fifth lens group (part G5 in the figure) and a sixth lens group (part G6 in the figure) which are sequentially arranged from an image surface 1 to an object plane 25 along the optical axis direction, wherein the first protection mirror is a plane mirror 2, the plane mirror 2 is a parallel flat protection mirror, the plane mirror 2 is used for protecting an internal optical element of the projection objective, ensuring the sealing of an optical system, the thickness of the plane mirror 2 is larger than that of the plane mirror 2 when the projection objective is in a wet projection state, the second lens group used for converging light beams has positive focal power, the fourth lens group used for diverging light beams and correcting the optical system of the objective has negative focal power, the plane mirror 2 is used for converging light beams, the fifth lens group used for diverging light beams has negative focal power, the fifth lens has a near-positive focal power, the optical system has a near-field lens is used for transmitting the projection objective, and the optical system has a near-field lens is used for transmitting the optical system; the principal rays of each view field of the image space are approximately emitted in parallel to the optical axis and converged on the image plane 1, so that the conjugate error of the object image plane is reduced, the installation error of the object plane 25 is reduced, the included angle between the image space and the optical axis is 2.5mrad, the image distance is more than 3.2mm, all lenses in the projection objective are spherical, the processing and the detection are convenient, the processing and manufacturing difficulty is reduced, the projection objective can reduce an object plane image by-0.25 times to an image plane, all lenses in the projection objective are made of ARF quartz glass materials, the plane mirror 2 can be replaced by parallel flat lenses with different thicknesses and is used for correcting optical path difference and aberration caused by immersion liquid when the projection objective is used in a dry projection state and a wet projection state, the projection objective is applicable to a deep ultraviolet band light source, the wavelength is 193.368nm, the resolution is higher, the spectral width can reach 1pm, the working distance of the object side of the projection objective is greater than 49mm, the working distance of the image side is greater than 3.2mm, the thickness of the plane mirror 2 is 35mm when the projection objective is in the dry projection state, the thickness of the plane mirror 2 is 32mm when the projection objective is in the wet projection state, the object plane size of the projection objective is 80mm, the image plane size of the projection objective is 20mm, the multiplying power of the projection objective is-0.25 times, the numerical aperture of the image side of the projection objective is 0.56 when the projection objective is in the dry projection state, the numerical aperture of the image side of the projection objective is 0.8, and the visual field of the image side is 20mm when the projection objective is in the wet projection state.
Above-mentioned dark ultraviolet is wet and dry dual-purpose projection objective, through the thickness of changing plane mirror 2 and then realize that projection objective carries out dry imaging and wet imaging's switching, make projection objective be applicable to different environment and different samples, increase projection objective's NA numerical value, improve objective's resolution, make its application scope more extensive, projection objective can also be through changing dry imaging and wet imaging mode and then change numerical aperture, when wet mode, can change numerical aperture through changing different immersion liquid.
As shown in fig. 1, in the present embodiment, the second lens group includes a first lens 3, a second lens 4, a third lens 5, a fourth lens 6, a fifth lens 7, a sixth lens 8, and a seventh lens 9, which are disposed in order from the image plane 1 to the object plane 25 along the optical axis direction, the first lens 3, the second lens 4, the third lens 5, the fourth lens 6, and the fifth lens 7 are meniscus lenses, the sixth lens 8, and the seventh lens 9 are biconvex lenses, and the meniscus directions of the first lens 3, the second lens 4, the third lens 5, the fourth lens 6, and the fifth lens 7 are all toward the image plane 1, wherein the sixth lens 8 and the seventh lens 9 are for converging light beams.
As shown in fig. 1, in the present embodiment, the third lens group includes an eighth lens 11, a ninth lens 12, and a tenth lens 13, which are disposed in order from the image plane 1 to the object plane 25 in the optical axis direction, the eighth lens 11, the ninth lens 12, and the tenth lens 13 each being a meniscus lens, the meniscus directions of the eighth lens 11, the ninth lens 12, and the tenth lens 13 each being directed toward the object plane 25, and the third lens group being for converging light beams.
As shown in fig. 1, in the present embodiment, the fourth lens group includes an eleventh lens 14, a twelfth lens 15, and a thirteenth lens 16 sequentially arranged from the image plane 1 to the object plane 25 along the optical axis direction, the eleventh lens 14, the twelfth lens 15, and the thirteenth lens 16 are all meniscus lenses, the meniscus directions of the eleventh lens 14, the twelfth lens 15, and the thirteenth lens 16 are not fixed, it is sufficient to ensure that the fourth lens group has negative optical power, the fourth lens group is adjusted by moving to compensate for axial defocus, the fourth lens group is used for beam divergence, and the fourth lens group is moved to correct for objective optical system defocus.
As shown in fig. 1, in the present embodiment, the fifth lens group includes a fourteenth lens 17, a fifteenth lens 18, and a sixteenth lens 19, which are disposed in order from the image plane 1 to the object plane 25 in the optical axis direction, each of the fourteenth lens 17 and the fifteenth lens 18 being a meniscus lens, the sixteenth lens 19 being a plano-convex lens, and the fifth lens group being for beam divergence, mainly for correcting distortion of an objective optical system.
As shown in fig. 1, in the present embodiment, the sixth lens group includes a seventeenth lens 20, an eighteenth lens 21, a nineteenth lens 22, a twentieth lens 23, and a twenty-first lens 24, which are disposed in order from the image plane 1 to the object plane 25 in the optical axis direction, the seventeenth lens 20, the eighteenth lens 21, the nineteenth lens 22, the twentieth lens 23, and the twenty-first lens 24 are all meniscus lenses, and the sixth lens group is mainly used for converging light beams.
As shown in fig. 1, the present invention further includes a deep ultraviolet wet and dry projection method, which is implemented based on the above-mentioned two-purpose projection objective for deep ultraviolet wet and dry, wherein in a dry projection state, the thickness of the plane mirror 2 is 35mm, firstly, an imaging object is disposed on the object plane 25, secondly, a light source emits light to sequentially pass through the imaging object, the sixth lens group, the fifth lens group, the fourth lens group, the third lens group, the second lens group and the plane mirror 2, and finally the imaging object is imaged on the image plane 1, and in a wet projection state, the thickness of the plane mirror 2 is reduced to 32mm, firstly, the imaging object is disposed on the object plane 25, secondly, the light source emits light to sequentially pass through the imaging object, the sixth lens group, the fifth lens group, the fourth lens group, the second lens group and the plane mirror 2, and finally the imaging object is imaged on the image plane 1;
The specific parameters of the projection objective in the dry projection state are shown in the table 1, the radius value R is positive value and represents that the curvature center is close to the image side, the radius value R is negative value and represents that the curvature center is close to the object side, and the units of the radius, the thickness and the caliber are millimeter;
table 1 specific parameters of the projection objective in the dry projection state
As shown in fig. 2-4, the projection objective provided by the invention has good performance in a dry projection objective state, as shown in fig. 5, which is a structure diagram of the projection objective in a wet projection state, is suitable for 193.368nm wave bands, the spectral width can reach 1pm, the magnification is-0.25 times, the numerical aperture of an image space is 0.8, and the field of view of the image space is phi 20mm;
As shown in fig. 6, 7 and 8, the performance of the projection objective in the dry projection state is equivalent to that of the projection objective in the wet projection state, the image quality is good, the design and use requirements are met, after the plane mirror 2 is replaced, immersion pure water is added, the refractive index is 1.4366164, in order to meet the system image quality requirements and the working distance requirements, the distance between the plane mirror 2 and the first lens 3 is increased, and the thickness of the plane mirror 2 is reduced, wherein the specific parameters of the plane mirror 2 when the projection objective is in the wet projection state are shown in table 2;
Table 2 specific parameters of the plane mirror 2 when the projection objective is in the wet projection state
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.