Disclosure of Invention
The invention aims to provide an electrode assembly and semiconductor pre-cleaning equipment, which can reduce local high electric field area and improve electric field strength uniformity.
In order to achieve the above object, the present invention is realized by the following technical scheme:
The electrode assembly comprises a first electrode and a second electrode which are stacked along the vertical direction, wherein the first electrode is positioned above the second electrode, and a cavity is arranged between the first electrode and the second electrode;
The first electrode is provided with an air inlet part and an expansion part, the air inlet part is provided with an air inlet, and the air inlet is communicated with the cavity;
The expansion part is provided with an upper part and a lower part opposite to the upper part, the upper part of the expansion part is connected with the air inlet part, and the lower part is provided with a lower surface opposite to the second electrode;
The lower surface of the expansion part is provided with a dielectric part, and the dielectric part is positioned in a connection area between the lower surface of the expansion part and the outer wall.
Optionally, the motor assembly further comprises a spacer, wherein the spacer is located between the first electrode and the second electrode and electrically isolates the first electrode from the second electrode, the spacer is provided with a first side wall opposite to the outer wall of the expansion part of the first electrode, and the surface of the first side wall is provided with an isolation layer.
Optionally, a separation gap is arranged between the first side wall of the spacer and the outer wall of the expansion part of the first electrode, and the dielectric part is further arranged on the outer wall of the expansion part of the first electrode.
Optionally, the dielectric portion fills in the separation gap.
Optionally, the first side wall of the spacer contacts with the outer wall of the expansion part of the first electrode, the dielectric part is arranged in the junction area of the lower surface of the expansion part of the first electrode and the first side wall of the spacer, the connection surface of the dielectric part and the first side wall is a first connection surface, and the connection surface of the dielectric part and the lower surface of the first electrode is a second connection surface.
Optionally, the dielectric portion forms a first contact width D on the first connection surface, and the dielectric portion forms a second contact width D on the second connection surface, wherein D is greater than or equal to D.
Optionally, the second electrode is provided with a third surface opposite to the first electrode, the lower surface of the first electrode expansion part and the third surface of the second electrode form an electrode distance L, and the first contact width D is smaller than the electrode distance L.
Optionally, the section of the dielectric part is fan-shaped or triangular.
Optionally, the connection part between the outer wall and the lower surface of the first electrode expansion part is an arc chamfer, and the dielectric part is arranged at the arc chamfer.
Optionally, the dielectric portion is a dielectric material with a dielectric constant of 4-6.
Optionally, the thickness of the dielectric part is greater than or equal to 0.2mm.
Optionally, the dielectric constant of the isolation layer is a dielectric material with a dielectric constant of 2-8, and the thickness of the isolation layer is greater than 0.1mm.
Optionally, the air inlet portion and the extension portion integrated into one piece of first electrode, the extension portion is the annular, the inner wall of extension portion is from the air inlet to keeping away from the direction diameter of air inlet and increase gradually, the outer wall diameter of extension portion is unchangeable.
A semiconductor precleaning apparatus includes an electrode assembly, and a process chamber disposed below the electrode assembly.
Compared with the prior art, the invention has the following advantages:
(1) The dielectric part is arranged on the lower surface of the first electrode expansion part and the outer wall of the expansion part, the dielectric constant of the dielectric part is positioned between the plasma in the cavity and the separator, and the electric field distribution is homogenized by introducing the dielectric part, so that the local electric field intensity is reduced. The dielectric part is arranged in the connection area between the lower surface of the expansion part and the outer wall, so that the influence on the electric field environment of other areas of the cavity is reduced.
(2) By arranging the isolation layer on the first side wall of the isolation piece, the interface characteristic of plasma in the isolation piece and the cavity is improved, the surface structure of the isolation piece is optimized, the surface flatness of the isolation piece is improved, and the uniformity of electric field distribution is further improved.
Detailed Description
The following provides a further detailed description of the proposed solution of the invention with reference to the accompanying drawings and detailed description. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for the purpose of facilitating and clearly aiding in the description of embodiments of the invention. For a better understanding of the invention with objects, features and advantages, refer to the drawings. It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the invention to the extent that any modifications, changes in the proportions, or adjustments of the sizes of structures, proportions, or otherwise, used in the practice of the invention, are included in the spirit and scope of the invention which is otherwise, without departing from the spirit or essential characteristics thereof.
The semiconductor device generally includes a wafer front end module (EFEM), a Load Lock chamber (Load Lock), a wafer transfer chamber (TM), and a process chamber (PM) connected in sequence, where the wafer front end module transports a wafer to the Load Lock chamber and performs a negative pressure pumping process, and then moves the wafer located in the Load Lock chamber to the wafer transfer chamber under the action of a manipulator in the wafer transfer chamber, and transfers the wafer to the process chamber for performing a corresponding process. According to the different semiconductor processes, the processes of pre-cleaning, epitaxy, etching, ion implantation and the like can be divided, and different processes correspond to different process chambers.
Fig. 1 is a schematic structural view of a semiconductor precleaning apparatus 100 according to the present invention, and as shown in fig. 1, the semiconductor precleaning apparatus 100 includes an electrode assembly, a distribution assembly, a process chamber, and a support assembly. The electrode assembly is disposed at an upper end of the process chamber. The motor assembly comprises a first electrode 10, a second electrode 11 and a separator 12 which are stacked in the vertical direction, wherein the first electrode 10 is positioned above the second electrode 11, a cavity 104 for confining plasma is arranged between the first electrode 10 and the second electrode 11, and a certain electrode distance L is arranged between the first electrode 10 and the second electrode 11. The first electrode 10 is connected to a power supply, further the power supply is a radio frequency power supply, and the second electrode is grounded, thereby forming a capacitance between the first electrode 10 and the second electrode 11.
The first electrode 10 includes an air inlet 101 and an expansion 102, and the expansion 102 is disposed below the air inlet 101. The air inlet part is provided with one or more air inlets 103, the air inlets 103 are communicated with the cavity 104, the reaction gas enters the cavity 104 through the air inlets 103, and the reaction gas entering the cavity 104 is excited to generate plasma. The air inlet part comprises a first surface 106 opposite to the second electrode and a second surface 107 opposite to the first surface, the air inlet 103 penetrates through the first surface 106 and the second surface 107 of the air inlet part, and further, the air inlet 103 is symmetrically distributed along the symmetrical center line of the cavity 104. Further, the air inlet 101 is further provided with a side surface connecting the first surface and the second surface, the air inlet pipeline is parallel to the second surface, the air inlet end of the air inlet pipeline is located on the side surface of the air inlet, and the air outlet end of the air inlet pipeline, that is, the air inlet 103 is symmetrically distributed along the symmetrical center line of the cavity. Optionally, the air inlet portion is disc-shaped.
In some embodiments, as shown in fig. 1 and 2, the expansion is a ring-shaped member having an upper portion connected to the first surface 106 of the air intake portion and a lower portion opposite the upper portion having a lower surface 205 opposite the lower electrode, and an inner wall 206 and an outer wall 204. The inner wall forms a side wall of the cavity 104, and the diameter of the inner wall of the expansion part gradually increases from the air inlet 103 to the direction away from the air inlet, and the inner wall of the expansion part is shaped like an inverted cone or a funnel. Further, the diameter of the inner wall of the expansion part is unchanged from the air inlet 103 to the direction away from the air inlet, i.e. the inner wall of the expansion part is cylindrical. One end of the outer wall 204 is connected to the first surface 106 of the air inlet portion, the other end of the outer wall is connected to the lower surface 205 of the expansion portion, and the diameter of the outer wall of the expansion portion is unchanged. The diameter of the outer wall of the expansion part is unchanged, namely when the expansion part is at a certain distance from the isolating piece, the distance between the outer wall of the expansion part and the isolating piece is kept unchanged, and the occurrence of ignition caused by overlarge local electric field due to the fact that the distance is reduced is avoided.
In some embodiments, as shown in fig. 1, a spacer 12 is disposed between the first electrode 10 and the second electrode 11, the spacer 12 realizing an electrical separation of the first electrode and the second electrode, the spacer 12 being an annular member, the spacer being disposed around or substantially around the expansion 102 of the first electrode, the height of the spacer being greater than the height of the expansion (i.e., the distance of the expansion from the first surface to the lower surface). The spacer 12 may be made of alumina ceramic or any other insulating material. The dielectric constant of the alumina ceramic is 9-10.
In some embodiments, the second electrode 11 is provided with a third surface 112 opposite to the first electrode 10, and the first electrode extension lower surface 205 forms an electrode distance L with the second electrode third surface 112, and by adjusting the electrode distance L, uniformity of plasma distribution between the first electrode 10 and the second electrode 11 can be improved. Further, the second electrode includes a plurality of gas passages 111, the plurality of gas passages 111 being formed below the cavity to allow plasma within the cavity to flow through the gas passages 111 into the process chamber 14. A distribution assembly (not shown) is further arranged below the gas channel of the second electrode, further the distribution assembly is a circular gas distribution plate, and the gas distribution plate is provided with openings, which can prevent free radicals flowing out of the gas channel from directly impinging on the surface of the wafer 15 by slowing down the gas flow and guiding the gas flow to be uniformly distributed.
In some embodiments, the support assembly 18 is positioned within the process chamber for carrying the wafer 5 during processing. During processing, the wafer may be raised by the support assembly into close proximity to the gas distribution plate so that radicals may act on the wafer surface.
In some embodiments, the process chamber 14 is further provided with a liner (not shown) disposed on an inner surface of the sidewall of the process chamber and around the support assembly 18 for uniformly distributing the process gas over the wafer surface and exhausting the remaining process gas out of the process chamber 14 after the process is completed.
In some embodiments, as shown in fig. 3A and 5A, the lower surface of the expansion is provided with a dielectric portion, which is located in a connection region 207 of the lower surface of the expansion and the outer wall.
When a radio frequency power source is applied to the first electrode 10, this results in a region of the cavity near the end 207 of the first electrode having a high electric field strength, which is significantly higher than the electric field strength elsewhere in the cavity. In order to improve the uniformity of the electric field intensity, a dielectric part is arranged at the end part 207 of the first electrode, wherein the dielectric part is made of a dielectric material with a dielectric constant of 4-6, and the dielectric constant of the dielectric part is between the plasma inside the cavity and the ceramic isolator. The dielectric part can be one or a mixture of several of epoxy resin, polyimide, polycarbonate, titanate, alumina or silicon carbide. The dielectric portion may be disposed on the connection region 207 between the lower surface and the outer wall of the extension portion by spraying, coating, electroplating, etc., and the specific method is determined according to the characteristics of the dielectric portion material, and is not limited thereto. The dielectric portion has the ability to shield the electric field, and by providing the dielectric portion at the end 207 of the first electrode, the electric field distribution can be altered, reducing the risk of direct discharge between the electrodes. The dielectric part is arranged at the end part 207 of the first electrode, namely the connection region 207 of the lower surface and the outer wall of the expansion part, so that the local electric field intensity of the cavity near the end part of the first electrode can be reduced, but the electric field environment of other regions, particularly the electric field environment above the gas channel of the second electrode, can not be influenced.
In some embodiments, as shown in fig. 6, the spacer is provided with a first sidewall opposite to the outer wall of the expansion of the first electrode, and the first sidewall surface is provided with a spacer layer 121. The dielectric material with the dielectric constant of 2-8 is used as the isolation layer, and the thickness of the isolation layer is larger than 0.1mm. Providing the spacer 121 on the first sidewall surface of the spacer may improve the interface characteristics between the spacer and the gas inside the cavity, and avoid the uneven distribution of electric field intensity due to uneven surface or material of the spacer itself.
In some embodiments, a separation gap is provided between the first sidewall of the separator and an outer wall of the expansion of the first electrode, which is also provided with the dielectric portion. Further, the dielectric portion is disposed on the outer wall of the extension portion near the lower surface. When a separation gap is arranged between the first side wall of the isolation piece and the first electrode, the electric field in the separation gap is strong due to the voltage difference between the first electrode and the isolation piece, and the dielectric part is arranged on the outer wall of the first electrode expansion part, so that the electric field distribution can be smoothed, and the local high electric field area is reduced.
In some embodiments, the dielectric portion fills in the separation gap. The air gap between the first electrode and the separator is filled by the dielectric part, and the dielectric part is used as an electric field homogenizing material, so that the local electric field intensity can be remarkably reduced.
In some embodiments, as shown in fig. 3A, the first side wall of the spacer contacts the outer wall of the expansion portion of the first electrode, the interface area between the lower surface of the expansion portion of the first electrode and the first side wall of the spacer is provided with a dielectric portion 16, the connection surface between the dielectric portion and the first side wall is a first connection surface 161, and the connection surface between the dielectric portion and the lower surface is a second connection surface 162. The dielectric part forms a first contact width D on the first connecting surface, and forms a second contact width D on the second connecting surface, wherein D is more than or equal to D. The thickness of the dielectric portion, that is, the second contact width is 0.2mm or more.
By providing the dielectric portion at the interface area between the lower surface of the first electrode extension and the first sidewall of the spacer, not only is the local electric field strength reduced by the dielectric portion, but also the distance between the first electrode and the spacer is increased, thereby reducing the local electric field strength. As shown in fig. 4A and fig. 4B, the local electric field intensity is 32201.1V/m after chamfering the end 207 of the first electrode, as shown in fig. 3A and fig. 3B, the first electrode is not chamfered, and a dielectric part is only arranged at the junction area 207 between the lower surface of the first electrode expansion part and the first side wall of the spacer, the dielectric part is made of dielectric material with a dielectric constant of 4, and the electric field intensity at the same position of the dielectric part is only 3113.8V/m, so that the local electric field intensity is greatly reduced, and the electric field is more uniform.
In some embodiments, the second electrode is provided with a third surface opposite to the first electrode, the first electrode extension lower surface forms an electrode distance L with the second electrode third surface, and the first contact width D is smaller than the electrode distance L.
In some embodiments, the dielectric portion is fan-shaped or triangular in cross-section. The connection surface of the dielectric part and the first side wall of the isolation piece is a first connection surface, and the connection surface of the dielectric part and the lower surface of the first electrode is a second connection surface. One side of the first connecting surface is connected with one side of the second connecting surface, the other side of the first connecting surface is connected with the other side of the second connecting surface through a curved surface, the section of the dielectric part is fan-shaped, and the other side of the first connecting surface is connected with the other side of the second connecting surface through a plane, so that the section of the dielectric part is triangular. The other side of the first connecting surface and the other side of the second connecting surface may be connected by other manners, which is not limited thereto.
In some embodiments, the junction of the outer wall and the lower surface of the first electrode extension is provided as an arc chamfer, and the dielectric portion is provided at the arc chamfer. As shown in fig. 5A, the dielectric portion may be disposed along the arc chamfer shape, and the thickness of the dielectric portion refers to the shortest distance from the chamfer outer edge to the dielectric portion outer edge, and the thickness of the dielectric portion is greater than or equal to 0.2mm. Further, the dielectric part forms a first contact width D on the first connecting surface, and forms a second contact width D on the second connecting surface, wherein D is larger than or equal to D.
As shown in fig. 4A and 4B, when a high-voltage electric field is applied to the first electrode, in order to prevent arc discharge caused by accumulation of charges at a sharp point, a rounded chamfering process is performed on the end 207 of the first electrode, but since the electric field is also strong in a region having a small radius of curvature, the arc chamfering process is performed only on the first electrode, that is, a problem that local high electric field strength cannot be effectively improved by increasing the radius of curvature. As shown in fig. 5A and 5B, by providing a dielectric portion, which is a dielectric material having a dielectric constant of 6, in the arc-shaped chamfer region. The electric field intensity at the inner chamfer of the cavity is 32201.1V/m under the same condition, and after the dielectric part is arranged at the chamfer, the electric field intensity at the same position is 10274.4V/m, which is reduced to 1/3 of the original electric field intensity, thus obviously improving the situation of the local over-strong electric field.
In some embodiments, the air inlet portion of the first electrode further comprises a first surface opposite the second electrode, the separator comprises an upper mounting surface and a lower mounting surface opposite the upper mounting surface, the first surface of the first electrode is connected to the upper mounting surface of the separator, and the third surface of the second electrode is connected to the lower mounting surface of the separator. A sealing element is further arranged between the first electrode and the upper assembly surface of the isolation element, the sealing element is an annular sealing ring, and a sealing element is also arranged between the third surface of the second electrode and the lower assembly surface of the isolation element, and the sealing element is an annular sealing ring.
It is noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element. In addition, the term "connected" herein means that A and B are directly connected, or that A and B are indirectly connected, such as A and B are connected by C, even by C and D, etc., and that A and B are connected either integrally, separately, detachably, or fixedly. The term "optional" in this context means that the technical feature may be combined with or without any feature herein.
While the present invention has been described in detail through the foregoing description of the preferred embodiment, it should be understood that the foregoing description is not to be considered as limiting the invention. Many modifications and substitutions of the present invention will become apparent to those of ordinary skill in the art upon reading the foregoing. Accordingly, the scope of the invention should be limited only by the attached claims.