Sample table for MPCVD equipment and MPCVD equipment
By setting a central protrusion and annular groove on the back of the sample stage of the MPCVD equipment, the heat dissipation rate is adjusted, and the heat distribution of the substrate is made uniform. This solves the problems of uneven diamond film thickness and high internal stress caused by plasma inhomogeneity, and improves the performance and quality of diamond film.
Patent Information
- Application Number
- CN202423185118.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-20
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-12-20
AI Technical Summary
In existing MPCVD equipment, uneven plasma distribution leads to uneven heat distribution on the substrate, resulting in inconsistent diamond film growth rates, uneven thickness, and high internal stress.
Design a sample stage with a central protrusion and an annular groove on the back. The groove depth increases from the central protrusion to the annular protrusion. By adjusting the heat dissipation rate to be faster at the center and slower at the edge of the substrate, uniform heat distribution can be achieved, ensuring that all areas of the substrate are heated evenly.
This resulted in a more uniform thickness and lower internal stress in the diamond film, improving its performance and quality.
Smart Images
Figure CN223548096U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of plasma chemical vapor deposition technology, and in particular to a sample stage and MPCVD equipment for MPCVD equipment. Background Technology
[0002] Diamond is widely used in various fields due to its excellent properties. Among the many methods for synthesizing diamonds artificially, microwave plasma chemical vapor deposition (MPCVD) is considered the preferred method for preparing high-quality, large-size diamonds due to its advantages such as no discharge electrode contamination and good controllability. MPCVD equipment generally includes a microwave device, a vacuum device, a gas supply device, a cooling device, and a plasma reaction chamber. The plasma reaction chamber, as the core structure, includes components such as a reaction chamber, a water-cooled stage, and a sample stage. The water-cooled stage and the sample stage are located inside the reaction chamber. The front of the sample stage is used to place the substrate, and the back of the sample stage is located on the water-cooled stage, which dissipates heat from the substrate on the sample stage.
[0003] In the preparation of diamond using MPCVD technology, plasma is formed above the substrate, and the plasma deposits a diamond film on the substrate. Due to various factors such as the design of the reaction chamber structure, disturbances from the mixed growth gas, and the sample stage, the plasma spheres within the reaction chamber are prone to displacement and non-uniformity. This plasma non-uniformity leads to uneven heat distribution on the substrate, such as higher temperatures in the center and lower temperatures at the edges. This results in inconsistent diamond film growth rates across different regions of the substrate, leading to uneven diamond film thickness (especially in large-area diamond films), significant internal stress, and decreased performance. It also affects subsequent grinding and polishing of the diamond film, ultimately resulting in poor performance and quality of the formed diamond film. Summary of the Invention
[0004] The first objective of this application is to provide a sample stage for MPCVD equipment to solve the technical problems existing in the prior art, which are caused by uneven heat distribution on the substrate due to non-uniform plasma, resulting in inconsistent growth rates of diamond films, and thus causing defects such as uneven thickness and high internal stress in the formed diamond films.
[0005] To achieve the above objectives, this application adopts the following technical solution:
[0006] A sample stage for an MPCVD equipment includes a sample stage body having a front side suitable for placing a substrate and a back side suitable for contacting a cooling stage. The back side has a central protrusion at its center and an annular protrusion at its edge. An annular groove is formed between the central protrusion and the annular protrusion. The depth of the annular groove increases from the central protrusion to the annular protrusion.
[0007] The sample stage provided in this application compensates for the characteristic of heat distribution (or plasma sphere distribution) of the substrate during the diamond film preparation process, which is characterized by a high center and gradually decreasing edges. This is achieved by setting a central protrusion and an annular groove on the back of the sample stage body, with the groove depth increasing from the central protrusion to the annular protrusion. This allows the central protrusion on the back of the sample stage body to directly contact the cooling stage, or for the distance between the central protrusion and the cooling stage to be closer, resulting in faster heat dissipation for the portion of the sample stage front corresponding to the central protrusion. Conversely, the annular groove portion does not contact the cooling stage and is further away from it, resulting in faster heat dissipation for the portion of the sample stage front corresponding to the annular protrusion. The heat dissipation rate of the groove is slow, and by gradually increasing the depth of the annular groove from the center outward, the heat dissipation rate of the part of the sample stage corresponding to the annular groove can be gradually slowed down from the center outward. This allows the heat dissipation rate of the substrate placed on the front of the sample stage to gradually slow down from the center outward. This results in a faster heat dissipation rate in the center of the substrate and a gradually slower heat dissipation rate at the edges. In other words, the heat loss rate in the central region of the substrate is faster, while the heat loss rate at the edges is gradually slower. This heat loss is compensated for by the high heat in the middle and gradually decreasing heat at the edges caused by the plasma ball above the substrate, so that the heat distribution in each region of the substrate tends to be balanced. Furthermore, the faster thermal conductivity at the center of the sample stage allows heat to be quickly conducted to the edges, thus reducing the high-temperature effect at the center as soon as possible. At the same time, the slower thermal conductivity at the edges of the sample stage prevents heat loss. Combined with the rapid heat conduction from the center, this effectively compensates for the low temperature at the edges, resulting in a uniform temperature distribution across the entire sample stage. This ensures that the substrate placed on it is heated evenly, guaranteeing consistent diamond film growth rates in all areas of the substrate. Consequently, a diamond film with more uniform thickness and lower internal stress is formed on the substrate, improving the performance and quality of the formed diamond film.
[0008] Furthermore, the bottom surface of the central protrusion is coplanar with the bottom surface of the annular protrusion, suitable for simultaneous contact with the cooling stage; or, it further includes a heat-conducting sheet disposed at the bottom of the central protrusion, the bottom surface of the heat-conducting sheet being coplanar with the bottom surface of the annular protrusion, suitable for simultaneous contact with the cooling stage. Optionally, the thermal conductivity of the heat-conducting sheet is greater than the thermal conductivity of the sample stage body. In this case, when the sample stage is placed on the cooling stage, the annular protrusion and the central protrusion on the back of the sample stage can simultaneously contact the cooling stage, improving the stability of the sample stage placed on the cooling stage; at the same time, since the bottom surface of the annular protrusion can directly contact the cooling stage, the gap between the back edge of the sample stage and the water-cooling stage is eliminated, avoiding the occurrence of plasma arcing at the back edge of the sample stage, which would affect the quality of diamond film deposition and growth on the front substrate. Furthermore, when the sample stage is placed on the cooling stage, the bottom surface of the central protrusion can directly contact the cooling stage or contact the cooling stage through the heat-conducting sheet. This can further improve the heat conduction rate of the corresponding central protrusion on the front of the sample stage, that is, it can quickly conduct the heat from the central protrusion to the cooling stage, improve the heat dissipation effect at the center of the sample stage, thereby further improving the thermal environment for diamond film growth and improving the uniformity of diamond film thickness.
[0009] Furthermore, the equivalent diameter of the central protrusion is 25-40 mm; and / or, the center of the central protrusion is offset from the center of the sample stage by 0-10 mm.
[0010] Generally, the size of the central protrusion and its offset from the center of the sample stage can be adaptively adjusted according to the characteristics of the heat distribution on the substrate (or the characteristics of the plasma sphere distribution). Here, controlling the size of the central protrusion within the range of 25-40 mm can more effectively ensure the heat transfer and dissipation efficiency at the center of the sample stage, making it suitable for substrates of most sizes and thus meeting the requirements of most diamond film sizes. This improves the applicability of the sample stage and eliminates the need to prepare multiple sample stages for different sizes, thereby saving on the manufacturing cost of diamond films. Similarly, by aligning the central protrusion with the center of the sample stage, or by having an offset of no more than 10 mm, the heat transfer and dissipation efficiency at the center of the sample stage can be more effectively ensured, making it suitable for substrates of most sizes and thus meeting the requirements of most diamond film sizes. This improves the applicability of the sample stage and eliminates the need to prepare multiple sample stages for different sizes, thereby saving on the manufacturing cost of diamond films.
[0011] Furthermore, the height of the inner wall of the annular groove is 0-1 mm; and / or, the height of the outer wall of the annular groove is 0.5-2 mm. Generally, the size of the annular groove can be adaptively adjusted according to the characteristics of the heat distribution on the substrate (or the characteristics of the plasma ball distribution). Here, by setting the height of the inner wall of the annular groove, i.e., the height of the central protrusion, to 0-1 mm, and the height of the outer wall of the annular groove, i.e., the height of the annular boss, to 0.5-2 mm, while ensuring that the groove depth gradually increases from the central protrusion to the annular boss, it is possible to avoid the groove depth being too large and affecting the overall quality of the sample stage, thereby ensuring the service life of the sample stage. It also avoids the groove depth being too small and failing to achieve the heat compensation and regulation effect, thus ensuring the overall temperature regulation effect of the sample stage on the substrate placed on it, further ensuring the uniformity of the diamond film thickness grown on it, and improving the film formation quality.
[0012] Furthermore, the height of the inner wall of the annular groove is 0.3-0.7 mm. Here, the height of the inner wall of the annular groove, which is also the height of the central protrusion, is 0.3-0.7 mm. Therefore, by adopting a structure with a certain height for the central protrusion, the distance between the annular groove and the cooling stage can be increased, further increasing the rate difference between heat transfer from the central protrusion and heat transfer from the air inside the annular groove. This allows heat to be transferred more quickly to the position on the front of the sample stage corresponding to the central protrusion, while heat to be transferred more slowly to the position corresponding to the annular groove. This further improves the uniformity of temperature distribution on the sample stage body, resulting in a more uniform temperature distribution on the substrate placed on it. Consequently, the diamond film grown on it has a more uniform thickness and lower internal stress, further improving the performance and quality of the diamond film.
[0013] Furthermore, along the central protrusion to the annular boss, the depth of the annular groove increases by a set value for each set reaction temperature difference. Optionally, the set reaction temperature difference is 50°C, and the groove depth is set to 0.5mm. Preferably, along the central protrusion to the annular boss, the depth of the annular groove increases by 0.5mm for each 50°C reaction temperature difference. By setting the relationship between temperature difference and groove depth, the trend of annular groove depth variation can be set more effectively and conveniently according to the temperature difference relationship on the substrate. This allows for more effective compensation of heat distribution on the substrate placed on the sample stage, thereby further improving the uniformity of heat distribution on the substrate, i.e., improving the uniformity of the diamond film growth environment temperature. Consequently, the deposited diamond film thickness is more uniform, and the internal stress is lower, further improving the performance and quality of the diamond film.
[0014] Furthermore, the front side is provided with a substrate groove suitable for accommodating the substrate, and the substrate groove is located within the outer ring contour of the annular groove. In this case, by making the outer edge of the substrate groove located inside the annular groove, the substrate groove on the front side of the sample stage is completely located within the area of the annular groove and the central protrusion on the back side of the sample stage. Thus, the substrate placed on the front side of the sample stage can be completely within the temperature regulation range, so as to effectively regulate the temperature of the substrate and further ensure the performance and quality of the diamond film grown on the substrate.
[0015] Furthermore, the diameter of the substrate trench is greater than or equal to the diameter of the substrate; and / or, the depth of the substrate trench is greater than or equal to the thickness of the substrate. Thus, by making the diameter of the substrate trench greater than or equal to the diameter of the substrate placed thereon, it is easier to place or remove the substrate from the substrate trench; by making the depth of the substrate trench greater than or equal to the thickness of the substrate placed thereon, the substrate can be completely embedded in the substrate trench, avoiding exposure of the substrate edges. This prevents arcing / discharge phenomena at the substrate edges from affecting the diamond film formation quality, thereby further improving the performance and quality of the diamond film formed on the substrate.
[0016] Furthermore, the difference between the diameter of the substrate trench and the diameter of the substrate is 0.5-1 mm; and / or, the difference between the depth of the substrate trench and the thickness of the substrate is 0.5-2 mm. Thus, by making the diameter of the substrate trench 0.5-1 mm larger than the diameter of the substrate placed on it, it is easier to place the substrate into or remove it from the substrate trench, and it avoids the situation where excessive diameter difference leads to gas deposition on the peripheral surface of the substrate or gas deposition on the back side of the substrate through the edge of the substrate, forming a diamond film. When the diamond film is deposited on the outer peripheral surface or back side of the substrate, it will also have a certain impact on its temperature distribution, thereby affecting the uniformity of the diamond film formation on the front side. Therefore, controlling the diameter difference to 0.5-1 mm can more effectively improve the thickness uniformity of the diamond film on the front side of the substrate, thus improving its quality and performance. In addition, by making the depth of the substrate trench 0.5-2mm greater than the thickness of the substrate placed on it, it is possible to more effectively avoid the edge of the substrate being exposed, and also to prevent the substrate placed on it from being too far away from the plasma ball due to the excessive depth of the substrate trench. This is more conducive to the efficient use of energy, avoids excessive loss, and saves the manufacturing cost of diamond film.
[0017] Furthermore, the depth of the substrate groove is 2-10 mm; and / or, the diameter of the substrate groove is 40-120 mm. Thus, by limiting the depth and diameter of the substrate groove to a specific range, the sample stage can be adapted to most substrates, thereby meeting the requirements of most diamond film sizes. This improves the applicability of the sample stage, eliminating the need to prepare multiple sample stages for different sizes, thus saving on the manufacturing cost of diamond films.
[0018] A second objective of this application is to provide an MPCVD apparatus comprising the sample stage described in any of the preceding claims. Therefore, the MPCVD apparatus possesses at least all the technical advantages of the aforementioned sample stage.
[0019] The sample stage used in the MPCVD equipment and the MPCVD equipment containing it, by setting a central protrusion and an annular groove with gradually varying groove depth on the back of the sample stage, can make the temperature distribution uniform throughout the entire sample stage body, so that the substrate placed on it can be heated uniformly, and can ensure that the growth rate of diamond film in each area of the substrate is consistent, thereby forming a diamond film with more uniform thickness and less internal stress on the substrate, thus improving the performance and quality of the formed diamond film. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the specific embodiments of this application or the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the mounting structure of the sample stage, substrate, and cooling stage for an MPCVD equipment provided in an embodiment of this application;
[0022] Figure 2 This is a schematic diagram of the structure of a sample stage for an MPCVD device provided in an embodiment of this application;
[0023] Figure 3 This is a schematic diagram of the structure of a sample stage for an MPCVD device provided in another embodiment of this application;
[0024] Figure 4 This is a schematic diagram of the mounting structure of the sample stage, substrate, and cooling stage for an MPCVD equipment provided in another embodiment of this application;
[0025] Figure 5 This is a schematic diagram of the structure of a diamond film prepared using a sample stage in the prior art.
[0026] Figure 6 This is a schematic diagram of the structure of the diamond film prepared using the sample stage provided in this application.
[0027] icon:
[0028] 1-Sample stage body; 11-Central protrusion; 12-Annular boss; 13-Annular groove; 14-Substrate groove;
[0029] 2-Heat-conducting sheet;
[0030] 100-substrate;
[0031] 200-Cooling platform. Detailed Implementation
[0032] The technical solutions of this application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0033] It should be noted that in the description of this application, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0034] It should be noted that, in the description of this application, the terms "connection" and "installation" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or a connection through an intermediate medium; they can refer to a mechanical connection or an electrical connection. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.
[0035] To address the technical problem of uneven diamond film growth rate due to uneven substrate heat distribution, resulting in diamond films with defects such as uneven thickness and high internal stress, this application provides, in one embodiment, a sample stage for an MPCVD device, referring to... Figure 1 The sample stage includes a sample stage body 1, which has a front side suitable for placing a substrate 100 and a back side suitable for contacting a cooling stage 200. A central protrusion 11 is provided at the center of the back side, and an annular protrusion 12 is provided at the edge of the back side. An annular groove 13 is formed between the central protrusion 11 and the annular protrusion 12. The depth of the annular groove 13 increases from the central protrusion 11 to the annular protrusion 12.
[0036] like Figure 1As shown, the cooling stage 200 is typically a water-cooled stage made of copper or molybdenum. The entire sample stage body 1 can be placed on the cooling stage 200 with its back side in contact with the cooling stage 200. The annular groove 13 on the back side of the sample stage body 1 separates the outer area of the sample stage body 1 from the cooling stage 200, thereby forming a heat-insulating space at the annular groove 13 that can accommodate air. Since the thermal conductivity of air is lower than that of the sample stage body 1, that is, lower than that of the central protrusion 11 of the sample stage, the heat dissipation effect at this heat-insulating space is worse than that at the central protrusion 11. During the preparation of diamond films, the plasma spheres formed by MPCVD equipment typically accumulate at the center of the sample stage and have a smaller distribution at the edges. Due to thermal radiation and other factors, the substrate placed on the sample stage exhibits a phenomenon where the center temperature is high and the edge temperature is low. Therefore, by setting a central protrusion 11 and an annular groove 13 on the back side, the uneven heat distribution caused by the plasma spheres can be specifically compensated. That is, by setting a central protrusion 11 and an annular groove 13 on the back side of the sample stage body 1, the central protrusion 11 on the back side of the sample stage body 1 can directly contact the cooling stage 200. If the central protrusion 11 is closer to the cooling stage 200, the portion of the sample stage front corresponding to the central protrusion 11 will dissipate heat faster. If the annular groove 13 is not in contact with the cooling stage 200 and is farther away from the cooling stage, the portion of the sample stage front corresponding to the annular groove 13 will dissipate heat slower. This allows the high-temperature region (central region) of the substrate 100 placed on the front of the sample stage to lose heat faster, while the low-temperature region (edge) to lose heat slower. This heat loss is compensated for by the high heat in the middle and low heat at the edges caused by the plasma ball above the substrate, so that the heat distribution in each region of the substrate 100 tends to be balanced. Furthermore, because the heat conduction rate at the center of the sample stage body 1 is faster, the heat at the center of the sample stage body 1 can be quickly conducted to the edge to reduce the high temperature effect at the center as soon as possible. At the same time, the heat conduction rate at the edge of the sample stage body 1 is slower, so that its heat is not easily lost. In addition, the combination of the heat conducted from the center can effectively compensate for the low temperature at the edge, so that the temperature is evenly distributed throughout the entire sample stage body 1. This ensures that the substrate 100 placed on it can be heated evenly, and can ensure that the growth rate of the diamond film in each area of the substrate is consistent, thereby forming a diamond film with a more uniform thickness on the substrate.
[0037] In some embodiments, the depth of the annular groove 13 increases from the central protrusion 11 to the annular boss 12. During the preparation of diamond films, the plasma spheres formed by the MPCVD equipment typically accumulate at the center of the sample stage and gradually decrease towards the edges. Due to thermal radiation and other reasons, the substrate placed on the sample stage exhibits a phenomenon where the temperature is high at the center and gradually decreases towards the edges. Therefore, by setting a sample stage with a central protrusion 11 and an annular groove 13 with a gradually decreasing depth on the back side, the uneven heat distribution caused by the plasma spheres can be specifically compensated. That is, by setting a central protrusion 11 and an annular groove 13 on the back side of the sample stage body 1, and making the depth of the annular groove 13 increase from the central protrusion 11 to the annular boss 12, the central protrusion 11 portion on the back side of the sample stage body 1 can directly contact the cooling stage 200, or the central protrusion 1... The closer the sample stage is to the cooling stage 200, the faster the heat dissipation rate of the part corresponding to the central protrusion 11 on the front side of the sample stage. The part of the annular groove 13 does not contact the cooling stage 200 and is farther away from the cooling stage, so the heat dissipation rate of the part corresponding to the annular groove 13 on the front side of the sample stage is slower. Furthermore, by gradually increasing the depth of the annular groove 13 from the center outward, the heat dissipation rate of the part corresponding to the annular groove 13 on the front side of the sample stage can be gradually slowed down from the center outward. This allows the heat loss rate of the high-temperature region (central region) of the substrate 100 placed on the front side of the sample stage to be faster, while the heat loss rate of the low-temperature region (edge) to be gradually slowed down. This heat loss is compensated for by the high heat in the middle and the gradually decreasing heat at the edges caused by the plasma ball above the substrate, so that the heat distribution of each region of the substrate 100 tends to be balanced. Furthermore, because the heat conduction rate at the center of the sample stage body 1 is faster, the heat at the center of the sample stage body 1 can be quickly conducted to the edge to reduce the high temperature effect at the center as soon as possible. At the same time, the heat conduction rate at the edge of the sample stage body 1 is slower, so that its heat is not easily lost. In addition, the combination of the heat conducted from the center can effectively compensate for the low temperature at the edge, so that the temperature is evenly distributed throughout the entire sample stage body 1. This ensures that the substrate 100 placed on it can be heated evenly, and can ensure that the growth rate of the diamond film in each area of the substrate is consistent, thereby forming a diamond film with a more uniform thickness on the substrate.
[0038] In some existing sample stages, a groove is provided on the placement surface of the substrate 100. This groove separates the peripheral area of the back side of the substrate 100 from the sample stage through air, thereby improving the uniformity of heat distribution on the substrate 100. However, this type of sample stage has more limitations on the size requirements of the substrate 100; that is, it can generally only place a substrate 100 that can completely cover the groove, and is not suitable for small-sized substrates 100. If the sample stage only touches the central area of the back side of the substrate 100, while the edge of the back side of the substrate 100 is exposed, plasma gas will enter the back side of the substrate 100, causing a diamond film to be deposited on the back side of the substrate 100. The diamond film deposited on the back side of the substrate 100 will also affect the temperature distribution on the substrate 100, thereby affecting the forming quality of the diamond film on the front side.
[0039] Compared to sample stages with grooves on the placement surface of the substrate 100, the sample stage provided in this application has a flat surface without grooves on the placement surface of the substrate 100. Therefore, the back side of the substrate 100 can completely conform to the placement surface, preventing plasma gas from entering the back side of the substrate 100. This avoids the impact of the diamond film formed on the back side of the substrate 100 on the diamond film grown on the front side, further improving the forming quality of the diamond film formed on the front side of the substrate 100. Furthermore, the sample stage provided in this application has higher adaptability and can be applied to substrates 100 of various diameters. Especially when placing smaller substrates 100, the planar placement surface ensures no gap between the back side of the substrate 100 and the placement surface, thus solving the problem of plasma gas potentially entering the bottom of the substrate 100.
[0040] In summary, the sample stage provided in this application is specifically compensated for based on the characteristics of heat distribution (or plasma ball distribution) of the substrate during the fabrication process. A central protrusion 11 and an annular groove 13 are provided on the back side of the sample stage body 1, with the central protrusion 11 corresponding to the high-temperature region of the substrate 100 and the annular groove 13 corresponding to the low-temperature region of the substrate 100. This improves the uniformity of temperature distribution on the substrate 100, thereby enhancing the consistency of the diamond film growth rate on the substrate 100 and preventing defects such as uneven thickness and high internal stress in the formed diamond film, thus improving the performance and quality of the formed diamond film. The front side of the sample stage body 1 is used to place the substrate 100, and the placement surface of the substrate 100 is a flat plane without grooves. This design ensures that there is no gap between the back side of the substrate 100 and the placement surface, preventing the deposition of diamond film on the back side of the substrate 100, thus further improving product quality. Furthermore, it enhances the adaptability of the sample stage, especially for the deposition of small-sized substrates 100.
[0041] It should be noted that the sample stage provided in this application can be used to prepare single-crystal or polycrystalline diamond films, as well as various other metal films, amorphous inorganic films, and organic films. The application of this sample stage is not limited here.
[0042] It should also be noted that the center position described in this application is relative to the edge position; that is, the center position is located inside the edge position, and it is not necessarily the position of the symmetry axis of the edge position. It can also be a position slightly to the left or right. For example, the center position can refer to the center (axis position) of the entire sample stage, or it can be a position that deviates from the axis to the left or right. Similarly, the edge position described in this application is the position close to the edge of the sample stage, which can be either the outermost edge of the sample stage or an edge slightly inside the outermost edge. As for the specific location of the center position and the edge position, they can be adaptively adjusted according to the actual needs, such as the characteristics of the plasma ball distribution, to ensure uniform heat distribution on the substrate 100 placed on the sample stage.
[0043] In some embodiments, the sample stage body 1 has an overall cylindrical structure and is made of molybdenum or tungsten. Since molybdenum has the advantages of both high temperature resistance and relatively low price, it is preferred that the sample stage body 1 be made of molybdenum.
[0044] As an optional embodiment, refer to Figures 1 to 3 In the axial section of the annular groove 13, the line corresponding to the bottom of the annular groove 13 includes at least one of the following: a straight line, a curve, and a stepped line. Figure 1 In the embodiment shown, the bottom of the annular groove 13 corresponds to a straight line in the axial section of the annular groove 13. Figure 2 In the embodiment shown, the bottom of the annular groove 13 corresponds to a curve in the axial section of the annular groove 13. Figure 3 In the illustrated embodiment, the line corresponding to the bottom of the annular groove 13 in the axial section of the annular groove 13 is a stepped line. All of the above structures can achieve the goal of increasing the groove depth of the annular groove 13 from the central protrusion 11 to the annular boss 12. The shape of the bottom of the annular groove 13 and the change in groove depth can be adaptively adjusted according to actual needs.
[0045] Continue to refer to Figure 1 As an optional embodiment, the cross-sectional profile of the central protrusion 11 is circular, elliptical, or polygonal, preferably circular. In some embodiments, the equivalent diameter of the central protrusion 11 can be 25-40 mm. In other embodiments, the center of the central protrusion 11 is offset from the center of the sample stage by 0-10 mm. In still other embodiments, the equivalent diameter of the central protrusion 11 can be 25-40 mm, and the center of the central protrusion 11 is offset from the center of the sample stage by 0-10 mm.
[0046] Typically, the size of the central protrusion 11 and its offset from the center of the sample stage can be adaptively adjusted according to the characteristics of the heat distribution on the substrate 100 (or the characteristics of the plasma ball distribution). Generally, the offset between the center of the central protrusion 11 and the center of the sample stage is 0 mm. Here, in some embodiments, by controlling the size of the central protrusion within the range of 25-40 mm, the heat transfer and dissipation efficiency at the center of the sample stage can be more effectively guaranteed, making it suitable for substrates of most sizes, thus meeting the requirements of most diamond film sizes, improving the applicability of the sample stage, and eliminating the need to prepare multiple sample stages for different sizes, thereby saving on the manufacturing cost of the diamond film. In other embodiments, by aligning the central protrusion with the center of the sample stage, or by having an offset of at most 10 mm, the heat transfer and dissipation efficiency at the center of the sample stage can be more effectively guaranteed, making it suitable for substrates of most sizes, thus meeting the requirements of most diamond film sizes, improving the applicability of the sample stage, and eliminating the need to prepare multiple sample stages for different sizes, thereby saving on the manufacturing cost of the diamond film.
[0047] As an optional embodiment, the height H1 of the inner wall of the annular groove 13 can be 0-1 mm. Preferably, the height H1 of the inner wall of the annular groove 13 is 0.3-0.7 mm, for example, the height H1 of the inner wall of the annular groove 13 is 0.5 mm. In other embodiments, the height H2 of the outer wall of the annular groove 13 is 0.5-2 mm. Preferably, the height H2 of the outer wall of the annular groove 13 is 1-2 mm, for example, the height H2 of the outer wall of the annular groove 13 is 1.5 mm.
[0048] Typically, the dimensions of the annular groove 13 can be adaptively adjusted according to the characteristics of the heat distribution (or the characteristics of the plasma ball distribution) on the substrate 100. Here, by setting the height of the inner wall of the annular groove 13, i.e., the height of the central protrusion, to 0-1 mm or 0.3-0.7 mm, and the height of the outer wall of the annular groove 13, i.e., the height of the annular boss 12, to 0.5-2 mm or 1-2 mm, while ensuring that the groove depth of the annular groove 13 gradually increases from the central protrusion to the annular boss 12, it is possible to avoid the groove depth being too large and affecting the overall quality of the sample stage, thereby ensuring the service life of the sample stage. Furthermore, it is possible to avoid the groove depth being too small and failing to achieve the heat compensation and regulation effect, thereby ensuring the overall temperature regulation effect of the sample stage on the substrate placed on it, that is, further ensuring the uniformity of the thickness of the diamond film grown on it, and improving its film formation quality.
[0049] Furthermore, in the above embodiments, the height of the inner wall of the annular groove 13 can be 0.3-0.7 mm. The height of the inner wall of the annular groove 13, i.e., the protrusion height of the central protrusion 11, is 0.3-0.7 mm. In the above embodiments, by adopting a structure with a certain height for the central protrusion 11, the distance between the annular groove 13 and the cooling stage is increased, further increasing the rate difference between heat transfer from the central protrusion 11 and the air heat transfer within the annular groove 13. This allows heat to be transferred more quickly to the position on the front of the sample stage corresponding to the central protrusion 11, while heat to be transferred more slowly to the position corresponding to the annular groove 13. This further improves the uniformity of temperature distribution on the sample stage body, resulting in a more uniform temperature distribution on the substrate 100 placed on it. Consequently, the diamond film grown on it has a more uniform thickness and lower internal stress, further improving the performance and quality of the diamond film.
[0050] Of course, the depth of the annular groove 13 can be adaptively adjusted according to the characteristics of the heat distribution on the substrate 100 (or the characteristics of the plasma ball distribution) to further improve the uniformity of the heat distribution on the substrate 100.
[0051] As an optional embodiment, the annular protrusion 12 along the center protrusion 11 at the center of the sample stage to the edge increases the depth of the annular groove 13 by a set value for each time a set reaction temperature difference is reached. In some embodiments, the set reaction temperature difference is 50°C, and the set groove depth is 0.5 mm.
[0052] For example, starting from the outer edge of the central protrusion 11, the depth of the annular groove 13 gradually increases towards the edge of the sample stage. The groove depth is appropriately adjusted according to the reaction temperature difference between the center and the edge of the reaction chamber. For example, for every 50°C difference, the depth of the annular groove 13 increases by 0.5 mm. By setting the relationship between the temperature difference and the groove depth, the trend of the annular groove depth can be set more effectively and conveniently according to the temperature difference on the substrate. This allows for more effective compensation of the heat distribution on the substrate placed on the sample stage, thereby further improving the uniformity of the heat distribution on the substrate, i.e., improving the uniformity of the temperature environment for diamond film growth. Consequently, the deposited diamond film has a more uniform thickness and lower internal stress, further improving the performance and quality of the diamond film.
[0053] Continue to refer to Figure 1 As an optional embodiment, the front side of the sample stage body 1 is provided with a substrate groove 14 suitable for accommodating the substrate 100. The bottom of the substrate groove 14 is a flat surface without grooves, and the substrate 100 can be completely attached to the bottom of the substrate groove 14. The substrate groove 14 can limit the relative position of the substrate 100 and the sample stage body 1, and prevent the substrate 100 from shifting.
[0054] In some embodiments, the substrate groove 14 may be located within the outer ring contour of the annular groove 13, that is, the annular groove 13 is located inside the substrate groove 14.
[0055] For example, in an embodiment where both the substrate groove 14 and the annular groove 13 are circular, the substrate groove 14 and the annular groove 13 are coaxially arranged, and the diameter of the substrate groove 14 is larger than the diameter of the annular groove 13. In this case, by placing the outer edge of the substrate groove 14 inside the annular groove 13, the substrate groove 14 on the front side of the sample stage is completely located within the area of the annular groove 13 and the central protrusion 11 on the back side of the sample stage. This allows the substrate 100 placed on the front side of the sample stage to be completely within the temperature regulation range (i.e., the structure on the back side of the sample stage), thereby effectively regulating the temperature of the substrate 100 and further ensuring the performance and quality of the diamond film grown on the substrate.
[0056] As an optional embodiment, the diameter of the substrate trench 14 is greater than or equal to the diameter of the substrate 100. To facilitate the placement of the substrate 100 into the substrate trench 14, the diameter of the substrate trench 14 is larger than the diameter of the substrate 100. This makes it easier to place or remove the substrate from the substrate trench.
[0057] As an optional embodiment, the depth of the substrate trench 14 is greater than or equal to the thickness of the substrate 100, so that the substrate 100 can be completely embedded in the substrate trench 14, avoiding the edge of the substrate 100 from being exposed, thereby preventing the diamond film formation quality from being affected when arcing / discharge occurs at the edge of the substrate 100. Thus, the performance and quality of the diamond film formed on the substrate can be further improved.
[0058] In some embodiments, the depth of the substrate trench 14 can be 2-10 mm. In other embodiments, the diameter of the substrate trench 14 can be 40-120 mm. In still other embodiments, the depth of the substrate trench 14 can be 2-10 mm, and the diameter of the substrate trench 14 can be 40-120 mm. Considering that the thickness of typical deposited samples varies from 1.5-6 mm, the depth of the substrate trench 14 can be set to 2-10 mm. The depth of the substrate trench 14 should be greater than (or greater than or equal to) the thickness of the substrate 100, so that the substrate 100 can be completely embedded in the substrate trench 14, preventing arcing / discharge phenomena and improving the quality of the diamond film deposited on the substrate. Considering that the diameter of typical substrate samples varies from 30-100 mm, such as 50.8 mm or 76.2 mm, the diameter of the substrate trench 14 can be set to 40-120 mm. This diameter range can be applied to most deposited samples, thereby improving the applicability of the sample stage.
[0059] Furthermore, if the diameter difference between the substrate groove 14 and the substrate 100 is too small, it will be difficult or even impossible for the substrate 100 to be placed into the substrate groove 14; if the difference is too large, gas will be deposited on the peripheral surface of the substrate 100 or deposited through the edge of the substrate 100 to the back surface of the substrate 100 to form a diamond film, affecting the temperature distribution, the overall internal stress of the diamond film, etc., and thus affecting the film formation quality of the diamond film.
[0060] Based on the above considerations, in some embodiments, the diameter difference between the substrate groove 14 and the substrate 100 is 0.5-1 mm. This diameter difference range facilitates the placement and removal of the substrate 100 from the substrate groove 14, while also preventing excessive diameter differences from causing gas deposition on the peripheral surface of the substrate 100 or from depositing a diamond film on the back side of the substrate 100 through the edge. When a diamond film is deposited on the outer peripheral surface or back side of the substrate, it will also have a certain impact on its temperature distribution, thereby affecting the uniformity of the diamond film formation on the front side. Therefore, controlling the diameter difference to 0.5-1 mm can more effectively improve the thickness uniformity of the diamond film on the front side of the substrate, thereby improving its quality and performance.
[0061] In some embodiments, the difference between the depth of the substrate trench 14 and the thickness of the substrate 100 is 0.5-2 mm. This range of depth and thickness difference can more effectively prevent the edge of the substrate 100 from being exposed, facilitate the placement and removal of the substrate 100, and prevent the substrate trench from being too deep, causing the substrate placed on it to be too far from the plasma ball, thereby making it more conducive to the efficient use of energy, avoiding excessive loss, and saving the manufacturing cost of the diamond film.
[0062] Taking all the above into consideration, preferably, the diameter of the substrate trench 14 is 50-105 mm and the depth of the substrate trench 14 is 3-8 mm. This size range is applicable to most deposited samples.
[0063] It should be noted that the size of the substrate trench 14 can be adaptively adjusted according to the substrate 100 to be prepared, and is not limited to the above-mentioned size.
[0064] Continue to refer to Figure 1As an optional embodiment, the bottom surface of the central protrusion 11 is coplanar with the bottom surface of the annular protrusion 12, suitable for simultaneous contact with the cooling stage 200. In the above structure, since the bottom surface of the annular protrusion 12 contacts the cooling stage 200, the gap between the bottom outer edge of the sample stage and the water-cooled stage 100 is eliminated, avoiding the occurrence of plasma arcing in the gap between the sample stage and the water-cooled stage 100 (i.e., within the annular groove 13). The bottom surface of the central protrusion 11 also contacts the cooling stage 200. This arrangement increases the contact area between the sample stage and the cooling stage 200, improving the stability of the sample stage, and also enables rapid heat transfer from the central protrusion 11 to the cooling stage 200, improving the heat dissipation effect at the center of the sample stage body 1.
[0065] Reference Figure 4 As another optional embodiment, the sample stage provided in this application further includes a heat-conducting plate 2 disposed at the bottom of the central protrusion 11. The bottom surface of the heat-conducting plate 2 is coplanar with the bottom surface of the annular protrusion 12, and is suitable for simultaneous contact with the cooling stage 200. The thermal conductivity of the heat-conducting plate 2 is greater than that of the sample stage body 1. In some embodiments, the heat-conducting plate 2 may be made of diamond or silicon carbide. Because the heat-conducting plate 2 is disposed at the bottom of the central protrusion 11, the heat dissipation effect at the center of the sample stage body 1 can be further improved, thereby making the temperature distribution more uniform across the entire sample stage body 1, thus further improving the thermal environment for diamond film growth and enhancing the thickness uniformity of the diamond film.
[0066] Figure 4 In the embodiment shown, a fixing groove may be provided on the bottom surface of the central protrusion 11, and the heat-conducting sheet 2 may be partially or completely embedded in the fixing groove to limit the relative position of the heat-conducting sheet 2 and the sample stage body 1.
[0067] One of the design processes for the sample stage provided in this application is as follows:
[0068] Step 1: Perform a single deposition using a sample stage without a groove on the back;
[0069] Specifically, a planar molybdenum wafer is used as the sample stage. A silicon wafer is placed on the front side of the sample stage, and the back side of the sample stage is placed on a cooling stage 200. Then, a plasma ball of gases such as carbon and hydrogen is formed in the reaction chamber of the MPCVD equipment, and the reaction is carried out on the front side of the planar molybdenum wafer for 50 hours to obtain a diamond film product. This diamond film product exhibits a structure with a convex center and concave edges (e.g., Figure 5 (as shown);
[0070] Step 2: Based on the thickness distribution of the diamond film product obtained in Step 1, targeted compensation is performed on the sample stage to determine the position and size of the central protrusion 11, the annular protrusion 12 and the annular groove 13, thereby manufacturing the sample stage provided in this application.
[0071] Step 3: Using the sample stage obtained in Step 2, perform deposition again with the same parameters as in Step 1 to obtain a diamond product with a more uniform thickness distribution (e.g., Figure 6 (As shown).
[0072] Practical verification has shown that the sample stage provided in this application can effectively improve the uniformity of the thickness of the formed diamond film and improve defects such as high internal stress in the diamond film.
[0073] Another embodiment of this application provides an MPCVD apparatus, which includes the sample stage described in any of the above embodiments. Therefore, this MPCVD apparatus possesses at least all the technical features and corresponding technical effects of the sample stage described above, which will not be repeated here.
[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A sample stage for an MPCVD equipment, characterized in that, Includes a sample stage body (1), the sample stage body (1) having a front side suitable for placing a substrate (100) and a back side suitable for contacting a cooling stage (200), wherein a central protrusion (11) is provided at the center of the back side and an annular protrusion (12) is provided at the edge of the back side, and an annular groove (13) is formed between the central protrusion (11) and the annular protrusion (12). The depth of the annular groove (13) increases from the central protrusion (11) to the annular boss (12).
2. The sample stage for MPCVD equipment according to claim 1, characterized in that, The bottom surface of the central protrusion (11) is coplanar with the bottom surface of the annular protrusion (12), and is adapted to contact the cooling platform (200) simultaneously. Alternatively, it may also include a heat-conducting plate (2) disposed at the bottom of the central protrusion (11), the bottom surface of the heat-conducting plate (2) being coplanar with the bottom surface of the annular protrusion (12), and being adapted to contact the cooling platform (200) simultaneously.
3. The sample stage for MPCVD equipment according to claim 1, characterized in that, The equivalent diameter of the central protrusion (11) is 25-40 mm; And / or, the center of the central protrusion (11) is offset from the center of the sample stage by 0-10 mm.
4. The sample stage for an MPCVD equipment according to claim 1, characterized in that, The height of the inner wall of the annular groove (13) is 0-1mm; And / or, the height of the outer wall of the annular groove (13) is 0.5-2 mm.
5. The sample stage for an MPCVD equipment according to claim 4, characterized in that, The height of the inner wall of the annular groove (13) is 0.3-0.7 mm.
6. The sample stage for an MPCVD equipment according to claim 1, characterized in that, Along the central protrusion (11) to the annular protrusion (12), the depth of the annular groove (13) increases by a set value for each set reaction temperature difference reached.
7. The sample stage for an MPCVD apparatus according to any one of claims 1 to 6, characterized in that, The front side is provided with a substrate groove (14) suitable for accommodating the substrate (100), and the substrate groove (14) is located within the outer ring contour of the annular groove (13).
8. The sample stage for an MPCVD equipment according to claim 7, characterized in that, The diameter of the substrate trench (14) is greater than or equal to the diameter of the substrate (100); And / or, the depth of the substrate trench (14) is greater than or equal to the thickness of the substrate (100).
9. The sample stage for an MPCVD apparatus according to claim 8, characterized in that, The difference between the diameter of the substrate trench (14) and the diameter of the substrate (100) is 0.5-1 mm; And / or, the difference between the depth of the substrate trench (14) and the thickness of the substrate (100) is 0.5-2 mm.
10. The sample stage for an MPCVD apparatus according to claim 7, characterized in that, The depth of the substrate trench (14) is 2-10 mm; And / or, the diameter of the substrate groove (14) is 40-120 mm.
11. An MPCVD device, characterized in that, Includes the sample stage as described in any one of claims 1 to 10.