Substrate platform system and mpcvd device

Abstract

A substrate stage system within an MPCVD (Multi-Level Chemical Vapor Deposition) device includes: a microwave reflector stage and a large molybdenum stage stacked together; a substrate stage disposed on the side of the large molybdenum stage away from the microwave reflector stage; wherein, an annular protrusion is provided on the side of the large molybdenum stage away from the microwave reflector stage, the annular protrusion being coaxial with the substrate stage and surrounding the outer periphery of the substrate stage. This arrangement, with the annular protrusion on the outer periphery of the substrate stage, ensures a more uniform plasma distribution above the substrate stage, thereby reducing the temperature difference between the center and the edge, ensuring a consistent diamond growth rate, reducing diamond crystal stress, and decreasing the cracking rate.

Description

[Technical Field]

[0001] This application relates to the field of semiconductor technology, specifically to a substrate stage system and MPCVD equipment. [Previous Technology]

[0002] With the expansion of the application fields of third-generation semiconductor materials, diamond, as the ultimate semiconductor material, has broad application prospects in many fields due to its characteristics such as large bandgap, high thermal conductivity, and high breakdown field strength.

[0003] Large-size diamonds are mainly grown using MPCVD (Microwave Plasma Chemical Vapor Deposition). During diamond growth, H2 and CH4 are used as the main reactive gases. The reactive gases are introduced into the resonant reaction chamber of the MPCVD equipment, and microwaves are fed in at the same time. The microwaves will generate a strong electric field above the substrate stage in the resonant reaction chamber. The strong electric field will ionize the reactive gases to form carbon-containing plasma groups. When the substrate meets the growth temperature range of 800℃-1200℃, the plasma groups diffuse to the substrate surface and diamond is deposited on the substrate surface.

[0004] When growing diamond, plasma is both a reaction source and a heat source. However, the plasma density distribution is often uneven, which leads to uneven temperature distribution of the substrate. When growing large-area diamonds, the temperature difference between the center and the edge of the substrate is large (the temperature difference between the center and the edge of the substrate within a distance of 20mm is 160K). This results in inconsistent growth rates, large thickness differences, and high stress between the center and the edge after the large-area diamond growth is completed, causing the diamond to bend or even break. [Summary of the Invention]

[0005] In view of this, this application provides a substrate stage system MPCVD equipment that can balance the radial temperature gradient on the upper surface of the substrate stage, ensure a consistent diamond growth rate, reduce diamond crystal stress, and reduce the cracking rate.

[0006] To achieve the above objectives, this application provides the following technical solution: A substrate stage system, comprising: a microwave reflector stage and a large molybdenum stage stacked together; a substrate stage disposed on the side of the large molybdenum stage away from the microwave reflector stage; wherein, an annular protrusion is provided on the side of the large molybdenum stage away from the microwave reflector stage, the annular protrusion being coaxial with the substrate stage and surrounding the outer periphery of the substrate stage. In some embodiments, the annular protrusion is spaced apart from the substrate stage; and / or, the surface of the annular protrusion on the side away from the large molybdenum stage is lower than the surface of the substrate stage on the side away from the large molybdenum stage.

[0007] In some embodiments, the inner circumferential surface of the annular protrusion near the substrate stage is perpendicular to the side of the large molybdenum stage away from the microwave reflector stage, and the side of the annular protrusion away from the substrate stage is set as an arc surface.

[0008] In some embodiments, a retainer is provided on the side of the large molybdenum stage away from the microwave reflector stage. The retainer surrounds the outer periphery of the substrate stage to position the substrate stage. The annular protrusion is arranged around the outer periphery of the retainer.

[0009] In some embodiments, the outer peripheral surface of the substrate stage contacts the cage through a first contact structure, wherein the first contact structure is configured as a line contact structure or a point contact structure for contacting the substrate stage.

[0010] In some embodiments, the first contact structure includes a plurality of first pointed protrusions disposed inside the retainer, the plurality of first pointed protrusions being distributed circumferentially along the substrate stage, and the tips of the first pointed protrusions abutting against the outer peripheral surface of the substrate stage.

[0011] In some embodiments, the large molybdenum stage is configured as a ring, and the side of the substrate stage facing the large molybdenum stage abuts against the large molybdenum stage.

[0012] In some embodiments, the substrate stage has a second contact structure on the side facing the large molybdenum stage, and the substrate stage contacts the large molybdenum stage through the second contact structure. The second contact structure is configured as a line contact structure or a point contact structure for contacting the large molybdenum stage.

[0013] In some embodiments, the second contact structure includes a second pointed protrusion disposed on the side of the substrate stage facing the large molybdenum stage and located at the edge of the substrate stage, the tip of the second pointed protrusion abutting against the surface of the large molybdenum stage away from the microwave reflector.

[0014] In some embodiments, a first positioning protrusion is provided on the side of the microwave reflector near the large molybdenum stage. The first positioning protrusion surrounds the outer periphery of the large molybdenum stage and can position the large molybdenum stage.

[0015] A metal stage is provided on the side of the microwave reflector away from the large molybdenum stage, and a second positioning protrusion is provided on the side of the microwave reflector away from the large molybdenum stage. The second positioning protrusion surrounds the outer periphery of the metal stage and can position the metal stage.

[0016] In some embodiments, it further includes: a heat sink; the large molybdenum stage and the microwave reflector stage are both arranged in a ring shape and are arranged around the outer periphery of the heat sink, and there is a gap between the substrate stage and the heat sink so that the heat sink can radiate heat to the substrate stage; wherein, a plurality of heat dissipation parts are formed sequentially from the middle to the edge on the side of the heat sink near the substrate stage, and the heat dissipation coefficient of the heat dissipation parts located in the middle and the edge of the heat sink is greater than the heat dissipation coefficient of the heat dissipation parts located between the middle and the edge of the heat sink, so as to compensate for the temperature of the substrate stage through non-uniform heat dissipation.

[0017] In some embodiments, the plurality of heat dissipation parts are made of the same material, and the surface roughness of the heat dissipation parts located in the middle and edge of the heat dissipation platform is greater than that of the heat dissipation parts located between the middle and edge of the heat dissipation platform.

[0018] In some embodiments, the plurality of heat dissipation parts are made of different materials, and the surface emissivity of the heat dissipation parts located in the middle and edge of the heat dissipation platform is greater than that of the heat dissipation parts located between the middle and edge of the heat dissipation platform.

[0019] In some embodiments, a radiative heat dissipation layer is provided on the side of the heat dissipation platform near the substrate stage. The radius of the radiative heat dissipation layer is smaller than the radius of the heat dissipation platform, so that the plurality of heat dissipation portions are sequentially formed from the center to the edge on the surface of the radiative heat dissipation layer and the side of the heat dissipation platform near the substrate stage.

[0020] In some embodiments, the plurality of heat dissipation parts are all made of oxygen-free copper, the surface roughness of the middle part of the radiative heat dissipation layer is set to 1.6 micrometers-3.2 micrometers, the surface roughness of the edge of the radiative heat dissipation layer is set to 0.3 micrometers-1.2 micrometers, and the roughness of the edge of the heat dissipation platform is set to 0.1 micrometers-0.6 micrometers.

[0021] In some embodiments, it further includes: a lifting assembly connected to the heat sink, the lifting assembly being used to move the heat sink axially closer to or further away from the substrate stage.

[0022] As another technical solution, this application also provides an MPCVD apparatus, including a reaction chamber and a substrate stage system as described in any of the preceding claims disposed in the reaction chamber.

[0023] The MPCVD equipment of the substrate stage system provided in this application has an annular protrusion on the side of the large molybdenum stage away from the microwave reflector stage (i.e., the upper surface of the large molybdenum stage), which surrounds the outer periphery of the substrate stage. During diamond growth, the electric field in the reaction chamber is 2.45 GHz. By setting the microwave reflector stage, a strong electric field region can be formed above the large molybdenum stage, realizing microwave plasma discharge. Since the annular protrusion surrounds the outer periphery of the substrate stage, the position of the annular protrusion can slightly induce edge discharge, guiding the discharge that was originally at the edge of the substrate stage to the annular protrusion. Although the annular protrusion weakens the absolute electric field above the substrate stage in the overall case, it can improve the radial electric field uniformity of the substrate stage from 15% to 8%, and can better flatten the plasma morphology, making the heat source relatively uniform. This configuration, with an annular protrusion on the outer periphery of the substrate stage, can make the plasma distribution above the substrate stage more uniform, thereby reducing the temperature difference between the center and the edge, ensuring a consistent diamond growth rate, reducing diamond crystal stress, and reducing the cracking rate.

Implementation Method

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0026] As shown in Figures 1-12, this application embodiment provides a substrate stage system disposed within a reaction chamber 3 for diamond growth, including a substrate stage 15 and a support assembly. The substrate stage 15 serves as a platform for placing the diamond substrate and supporting the grown diamond. The support assembly supports the substrate stage 15 to fix it in place.

[0027] In the specific solution, as shown in Figures 1-3, the support assembly includes a metal stage 11 (e.g., a metal material with good thermal conductivity such as copper), a microwave reflector stage 12, a large molybdenum stage 13, and a retainer 14 (e.g., a high-temperature resistant material). The metal stage 11, the microwave reflector stage 12, and the large molybdenum stage 13 are stacked sequentially from bottom to top, that is, the microwave reflector stage 12 is located between the metal stage 11 and the large molybdenum stage 13.

[0028] An annular protrusion 131 is provided on the side of the large molybdenum stage 13 away from the microwave reflector stage 12 (i.e., the upper surface of the large molybdenum stage 13), and the annular protrusion 131 surrounds the outer periphery of the substrate stage 15. The annular protrusion 131 is, for example, coaxial with the substrate stage 15. Please refer to Figures 10 to 12 together. Figure 10 is a simulation diagram of the electric field without the annular protrusion. Figure 11 is a simulation diagram of the electric field with the annular protrusion. During the diamond growth process, the electric field in the reaction chamber 3 is 2.45 GHz, as shown in Figure 11. By setting the microwave reflector stage 12, a strong electric field region can be formed above the large molybdenum stage 13 to realize microwave plasma discharge. Since the annular protrusion 131 surrounds the outer periphery of the substrate stage 15, the position of the annular protrusion 131 can slightly induce edge discharge, guiding the discharge that was originally at the edge of the substrate stage 15 to the annular protrusion 131. Although the annular protrusion 131 weakens the absolute electric field above the substrate stage 15 in the overall case, as shown in Figure 12, the radial electric field uniformity of the substrate stage 15 (the electric field uniformity = (maximum electric field value - minimum electric field value) / maximum electric field value, where the smaller the uniformity, the more uniform the electric field) can be increased from 15% (the electric field uniformity without the annular protrusion) to 8% through the annular protrusion 131, and the plasma shape can be flattened better, making the heat source relatively uniform.

[0029] With this configuration, the annular protrusion 131 is provided on the outer periphery of the substrate stage 15, which can make the plasma distribution above the substrate stage 15 more uniform, thereby reducing the temperature difference between the center and the edge, ensuring a consistent diamond growth rate, reducing diamond crystal stress, and reducing the cracking rate.

[0030] Further, the annular protrusion 131 does not contact the edge of the substrate stage 15 (i.e., the annular protrusion 131 is spaced apart from the substrate stage 15), and / or, the surface of the annular protrusion 131 away from the large molybdenum stage 13 is lower than the surface of the substrate stage 15 away from the large molybdenum stage 13, that is, the height of the upper surface of the annular protrusion 131 is lower than the height of the upper surface of the substrate stage 15. For example, the height difference between the upper surface of the annular protrusion 131 and the upper surface of the large molybdenum stage 13 is set to 3 mm-5 mm. Therefore, even if the annular protrusion 131 discharges slightly, it will not deteriorate the temperature uniformity of the substrate stage 15, and the edge of the substrate stage 15 can be controlled. The growth rate of polycrystalline diamond at the edge is always lower than that of the single-crystal diamond seed placed on the substrate stage 15 (the thickness of the single-crystal diamond seed is 0.2 mm and it is placed on the upper surface of the substrate stage 15), which effectively prevents polycrystalline diamond from affecting the deposition of single crystal (during the growth process, polycrystalline diamond is deposited at the annular protrusion 131 as a by-product of the process. If the upper surface of the annular protrusion 131 is higher than the upper surface of the substrate stage 15, the tip discharge at the annular protrusion 131 will become stronger, and the growth rate of polycrystalline diamond at the annular protrusion 131 will become faster. After a long period of growth, the polycrystalline diamond will grow thicker and affect the growth of single crystal on the upper surface of the substrate stage 15).

[0031] In one embodiment, the inner circumferential radius of the annular protrusion 131 can be set to 26 mm-35 mm, that is, the distance between the annular protrusion 131 and the central axis of the reaction chamber 3 is 26 mm-35 mm. Since diamond growth generally uses 2.45 GHz microwaves, the wavelength of which is 122 mm, and the diameter of the large molybdenum stage 13 is 90 mm-110 mm, the annular protrusion 131 can focus the electric field to half the wavelength, that is, focus it on the substrate stage 15, so that the electric field at the edge of the substrate stage 15 is more uniform than when the annular protrusion 131 is not set, and further flatten the plasma.

[0032] The side of the annular protrusion 131 near the substrate stage 15 (i.e., the inner circumferential surface of the annular protrusion 131) is set to a vertical shape, that is, the inner circumferential surface of the annular protrusion 131 is perpendicular to the upper surface of the molybdenum stage 13. The side of the annular protrusion 131 away from the substrate stage 15 (i.e., the outer circumferential surface of the annular protrusion 131) is set to an arc surface. In this way, the tip discharge of the outer circumferential edge of the annular protrusion 131 can be avoided.

[0033] In some embodiments, a retainer 14 is provided on the side of the large molybdenum stage 13 away from the microwave reflector stage 12 (i.e., the upper surface of the large molybdenum stage 13). The retainer 14 surrounds the outer periphery of the substrate stage 15 to position the substrate stage 15. At the same time, an annular protrusion 131 is arranged around the outer periphery of the retainer 14 to position the retainer 14. For example, the inner peripheral surface of the annular protrusion 131 is matched with the outer peripheral surface of the retainer 14. In this way, the radial positioning of the retainer 14 can be achieved through the positional matching between the annular protrusion 131 and the substrate stage 15, which helps to ensure the accurate and stable position of the retainer 14 relative to the large molybdenum stage 13.

[0034] The outer peripheral surface of the substrate stage 15 contacts the retainer 14 through a first contact structure. The first contact structure is configured as a line contact structure or a point contact structure for contacting the substrate stage 15. This can reduce the contact area between the substrate stage 15 and the retainer 14, reduce the heat conduction generated by the contact, and help ensure the temperature stability of the heat sink 18.

[0035] As shown in Figure 4, the first contact structure includes a plurality of first pointed protrusions 141. The plurality of first pointed protrusions 141 are disposed on the inner side of the retainer 14 (the side near the substrate stage 15) and are distributed around the circumference of the substrate stage 15. The radial positioning of the substrate stage 15 is achieved by the tip of the plurality of first pointed protrusions 141 abutting against the substrate stage 15. For example, the first pointed protrusion 141 is set as a triangular protrusion, and the size of the first pointed protrusion 141 gradually decreases in the direction near the substrate stage 15. The contact between the ridge of the first pointed protrusion 141 and the substrate stage 15 is a line contact, and the contact surface is small, which is beneficial to reduce heat conduction.

[0036] In some embodiments, the large molybdenum stage 13 is configured as an annular shape, and the side of the substrate stage 15 facing the large molybdenum stage 13 abuts against the large molybdenum stage 13, thereby achieving support of the substrate stage 15 by the large molybdenum stage 13. Specifically, the entire support assembly can be configured as an annular shape, and support of the substrate stage 15 can be achieved by the large molybdenum stage 13 abutting against the edge of the substrate stage 15. In this way, the contact area between the large molybdenum stage 13 and the substrate stage 15 is small, which helps to reduce contact heat transfer and reduce the impact on the temperature of the substrate stage 15.

[0037] Furthermore, the substrate stage 15 has a second contact structure on the side (i.e., the lower surface) facing the large molybdenum stage 13. The substrate stage 15 contacts the large molybdenum stage 13 through this second contact structure. The second contact structure is configured as a line contact structure or a point contact structure for contacting the large molybdenum stage 13. This can reduce the contact area between the substrate stage 15 and the large molybdenum stage 13, reduce the heat conduction generated by the contact, and help ensure the temperature stability and adjustable precision of the heat sink 18.

[0038] As shown in Figure 5, the second contact structure includes a second pointed protrusion 151, which is disposed on the lower surface edge of the substrate stage 15. The tip of the second pointed protrusion 151 abuts against the upper surface of the large molybdenum stage 13 (i.e., the surface away from the microwave reflector stage 12) to support the substrate stage 15. For example, the second pointed protrusion 151 is configured as an annular protrusion, and the size of the second pointed protrusion 151 gradually decreases along the direction close to the heat sink 18. The contact between the tip of the second pointed protrusion 151 and the large molybdenum stage 13 is a line contact, which is beneficial to reduce heat conduction.

[0039] As shown in Figure 3, a first positioning protrusion is provided on the side of the microwave reflecting stage 12 near the large molybdenum stage 13. The first positioning protrusion is located on the upper surface of the microwave reflecting stage 12 and achieves radial positioning of the large molybdenum stage 13 by surrounding it. For example, as shown in Figure 3, the first positioning protrusion is set as a first annular protrusion 121 on the upper surface of the microwave reflecting stage 12. As shown in Figures 1-2, a second positioning protrusion is provided on the side of the microwave reflecting stage 12 near the metal stage 11. The second positioning protrusion is located on the lower surface of the microwave reflecting stage 12 and surrounds the outer periphery of the metal stage 11 to achieve radial positioning of the metal stage 11. For example, the second positioning protrusion is set as a second annular protrusion 122 on the lower surface of the microwave reflecting stage 12. In this way, by setting the first positioning protrusion and the second positioning protrusion, the radial positioning of the metal stage 11, the microwave reflecting stage 12, and the large molybdenum stage 13 can be achieved, which is beneficial to maintaining the coaxiality of the three.

[0040] The substrate stage system provided in this embodiment further includes a heat sink 18. A support component is annular and surrounds the outer periphery of the heat sink 18. The support component supports the edge of the substrate stage 15 to fix the substrate stage 15. Specifically, the metal stage 11, microwave reflector stage 12, and large molybdenum stage 13 are all annular and surround the outer periphery of the heat sink 18. For example, the gap between the heat sink 18 and the metal stage 11 is set to 0.1 mm. In this way, the support component is fitted onto the heat sink 18, and the support component can radially limit the position of the heat sink 18, thereby improving the positional stability of the heat sink 18.

[0041] Furthermore, the heat sink 18 is disposed below the substrate stage 15. The heat sink 18 and the substrate stage 15 are coaxial and spaced apart, with a gap formed between them, so that the heat sink 18 dissipates heat from the substrate stage 15 through radiation. For example, both the heat sink 18 and the substrate stage 15 are cylindrical, with their central axes on the same straight line. The substrate is placed on top of the substrate stage 15, and the heat sink 18 is located below the substrate stage 15.

[0042] Specifically, the heat sink 18 is provided with a heat dissipation channel inside. The heat dissipation medium flowing in the heat dissipation channel dissipates heat to the surface of the heat sink 18 near the substrate stage 15. By making the temperature of the heat sink 18 lower than the temperature of the substrate stage 15, radiative heat dissipation of the substrate stage 15 is achieved.

[0043] The upper surface of the heat sink 18 is the surface near the substrate stage 15. The upper surface of the heat sink 18 has multiple heat dissipation parts, which are arranged sequentially from the middle to the edge of the heat sink 18. The heat dissipation coefficient of the heat dissipation parts located in the middle and the edge is greater than that of the other heat dissipation parts (the other heat dissipation parts are located between the middle and the edge of the heat sink 18, and the number can be set to one, two or three), so that the heat dissipation coefficients at different positions on the upper surface of the heat sink 18 are different, and the temperature on the substrate stage 15 is compensated by non-uniform heat dissipation.

[0044] It is understood that the number of heat dissipation parts can be set to three, four, or five. This solution is set to three, and the solution with three heat dissipation parts will be specifically explained as an example, as shown in Figures 6A and 6B. These three heat dissipation parts include a first heat dissipation part 161, a second heat dissipation part 162, and a third heat dissipation part 163. The first heat dissipation part 161, the second heat dissipation part 162, and the third heat dissipation part 163 are arranged sequentially from the middle to the edge of the upper surface of the heat dissipation platform 18. The first heat dissipation part 161 is set to be circular and located in the middle of the heat dissipation platform 18, and is used to radiate heat dissipation to the middle area of ​​the substrate stage 15. The second heat dissipation part 162 is set to be annular and surrounds the outer periphery of the first heat dissipation part 161, and is used to radiate heat dissipation to the near edge area of ​​the substrate stage 15. The third heat dissipation part 163 is set to be annular and surrounds the outer periphery of the second heat dissipation part 162, and is used to radiate heat dissipation to the outermost edge area of ​​the substrate stage 15. The heat dissipation coefficients of the first heat dissipation part 161, the second heat dissipation part 162, and the third heat dissipation part 163 are different. The heat dissipation coefficients of the first heat dissipation part 161 and the third heat dissipation part 163 are greater than those of the second heat dissipation part 162, so that the heat dissipation coefficients of different positions on the upper surface of the heat dissipation platform 18 are different, and the temperature on the substrate stage 15 is compensated by non-uniform heat dissipation.

[0045] During the diamond growth process, the plasma above the substrate stage 15 transfers heat to the substrate stage 15 through radiation. Due to the presence of a sheath at the edge of the plasma, the temperature in the middle region of the upper surface of the substrate stage 15 is high, while the temperature near the edge is low. Furthermore, due to the presence of tip discharge in the outermost region of the substrate stage 15, the temperature in the outermost region of the substrate stage 15 is higher than the temperature in the region near the edge. The temperature of the upper surface of the substrate stage 15 is conducted to the lower surface of the substrate stage 15 through the solid heat transfer inside the substrate stage 15. The temperature of the lower surface of the substrate stage 15 is then radiated to the upper surface of the heat sink 18. Since the heat dissipation coefficient of the heat dissipation part in the middle and edge of the heat sink 18 is greater than that of other heat dissipation parts (other heat dissipation parts are located between the middle and edge of the heat sink 18, and their number can be set to one, two or three), the heat conduction efficiency of the middle and outermost regions of the substrate stage 15 is high, while the heat conduction efficiency of the region near the edge is low. Thus, non-uniform compensation radiation heat dissipation is carried out for different regions on the substrate stage 15, which can better balance the radial temperature gradient of the upper surface of the substrate stage 15, making the radial temperature gradient of the substrate stage 15 better than 20K.

[0046] With this configuration, the heat dissipation coefficient of multiple heat dissipation parts on the heat dissipation stage 18 can be designed to perform non-uniform compensation radiation heat dissipation for different areas on the substrate stage 15, which can better balance the radial temperature gradient on the upper surface of the substrate stage 15, ensure a consistent diamond growth rate, reduce diamond crystal stress, and reduce the cracking rate.

[0047] It should be noted that the relationship between the heat dissipation coefficients of the heat dissipation sections (i.e., the first heat dissipation section 161 and the third heat dissipation section 163) located in the middle and at the edge of the heat dissipation platform 18 is related to the specific structure of the substrate stage system, and therefore is not specifically limited. For example, the heat dissipation coefficient of the first heat dissipation section 161 is greater than that of the second heat dissipation section 162.

[0048] In some embodiments, as shown in FIG6A, a radiative heat dissipation layer 16 is provided on the surface (upper surface) of the heat dissipation platform 18 near the substrate stage 15. The radius of the radiative heat dissipation layer 16 is equal to the radius of the upper surface of the heat dissipation platform 18. That is, the radiative heat dissipation layer 16 completely covers the upper surface of the heat dissipation platform 18, so that the middle region, the near edge region and the outermost edge region of the radiative heat dissipation layer 16 sequentially form a first heat dissipation part 161, a second heat dissipation part 162 and a third heat dissipation part 163. The material is the same everywhere on the radiative heat dissipation layer 16. The surface roughness of the middle region and the outermost edge region of the radiative heat dissipation layer 16 is greater than the surface roughness of the near edge region of the radiative heat dissipation layer 16. The specific surface roughness value depends on the specific situation.

[0049] Specifically, multiple heat dissipation parts (such as the first heat dissipation part 161, the second heat dissipation part 162 and the third heat dissipation part 163) are made of the same material (such as oxygen-free copper). The surface roughness of the heat dissipation parts located in the middle and edge of the heat dissipation platform 18 is greater than that of other heat dissipation parts (the other heat dissipation parts are located between the middle and edge of the heat dissipation platform 18, and the number can be set to one, two or three). Since the smaller the surface roughness, the lower the emissivity and the worse the heat absorption effect, the heat dissipation coefficient of different areas (the first heat dissipation part 161, the second heat dissipation part 162 and the third heat dissipation part 163) on the heat dissipation platform 18 can be adjusted by adjusting the surface roughness. During diamond growth, the temperature radiation from the lower surface of the substrate stage 15 is transferred to multiple heat dissipation sections on the upper surface of the heat sink 18. The heat dissipation sections located in the middle and edges of the heat sink 18 (i.e., the first heat dissipation section 161 and the third heat dissipation section 163) have a higher surface roughness and emissivity, resulting in better heat absorption. Conversely, the heat dissipation section located between the middle and edges of the heat sink 18 (i.e., the second heat dissipation section 162) has a lower surface roughness and emissivity, resulting in poorer heat absorption. Thus, by designing different surface roughnesses for the same material, non-uniform heat dissipation is achieved in different areas of the substrate stage 15, which can better balance the radial temperature gradient on the upper surface of the substrate stage 15, ensuring that the radial temperature gradient of the substrate stage 15 is better than 20K.

[0050] In other embodiments, based on the complete coverage of the radiative heat dissipation layer 16 on the upper surface of the heat sink 18, multiple heat dissipation parts are made of different materials (e.g., molybdenum, stainless steel, graphene, etc.). The surface emissivity of the heat dissipation parts located in the middle and edge of the heat sink 18 (the first heat dissipation part 161 and the third heat dissipation part 163) is greater than the surface emissivity of the heat dissipation part located between the middle and edge of the heat sink 18 (the second heat dissipation part 162). In this way, by using different materials with different surface emissivity, non-uniform heat dissipation is achieved in different areas of the substrate stage 15, which can better balance the radial temperature gradient on the upper surface of the substrate stage 15, making the radial temperature gradient of the substrate stage 15 better than 20K. In a specific scheme, the first heat dissipation part 161 is made of molybdenum, the second heat dissipation part 162 is made of stainless steel, and the third heat dissipation part 163 is made of graphene.

[0051] Alternatively, multiple heat dissipation parts are configured with coatings of different surface emissivity, which are applied to different areas of the heat dissipation stage 18 to achieve non-uniform heat dissipation to different areas of the substrate stage 15.

[0052] In some other embodiments, as shown in Figures 1 and 6B, a radiative heat dissipation layer 16 is provided on the surface (upper surface) of the heat sink 18 near the substrate stage 15. The radius of the radiative heat dissipation layer 16 is smaller than the radius of the upper surface of the heat sink 18, so that multiple heat dissipation portions are sequentially formed from the middle to the edge of the upper surface (i.e., the surface near the substrate stage 15) of the radiative heat dissipation layer 16 and the heat sink 18. Specifically, the middle and edge of the radiative heat dissipation layer 16 form a first heat dissipation portion 161 and a second heat dissipation portion 162, respectively, and the edge of the heat sink 18 where the radiative heat dissipation layer 16 is not provided forms a third heat dissipation portion 163. In this way, multiple heat dissipation portions are formed by the positional coordination of the radiative heat dissipation layer 16 and the upper surface of the heat sink 18, resulting in a relatively simple structure and easy processing.

[0053] The heat sink 18 and the radiative heat sink 16 are both made of oxygen-free copper. The surface roughness of the middle part of the radiative heat sink 16 (i.e., the first heat sink 161) is set to 1.6 micrometers to 3.2 micrometers. The surface roughness of the edge of the radiative heat sink 16 (i.e., the second heat sink 162) is set to 0.3 micrometers to 1.2 micrometers. The surface roughness of the edge of the heat sink 18 without the radiative heat sink 16 (i.e., the third heat sink 163) is set to 0.1 micrometers to 0.6 micrometers.

[0054] In the specific solutions of the above embodiments, the radius of the first heat dissipation part 161 is set to 15 mm-18 mm, and the radius of the second heat dissipation part 162 is set to 18 mm-25 mm. In this way, based on the traditional size setting of the substrate stage 15, the first heat dissipation part 161 and the second heat dissipation part 162 can dissipate heat for specific areas on the substrate stage 15, further improving the temperature distribution uniformity of the substrate stage 15.

[0055] This substrate stage system also includes a lifting assembly connected to a heat sink 18. The lifting assembly is used to move the heat sink 18 axially closer to or further away from the substrate stage 15, thereby changing the gap between the substrate stage 15 and the heat sink 18. After the diamond grows to a certain thickness, the thickening of the diamond layer deposited on the upper surface of the substrate stage 15 will cause the temperature to rise. In order to ensure that the diamond is always at the optimal growth temperature (860 degrees Celsius ± 5 degrees Celsius), the height of the heat sink 18 is finely adjusted by the lifting assembly during the growth process so that the heat sink 18 is closer to the substrate stage 15. By reducing the gap between the upper surface of the heat sink 18 and the lower surface of the substrate stage 15, the heat dissipation capacity of the substrate stage 15 can be improved, and the temperature of the diamond deposited on the upper surface of the substrate stage 15 can be further reduced to the optimal growth temperature range. In this way, the temperature is controlled in real time during the growth process. By adjusting the gap between the upper surface of the heat sink 18 and the lower surface of the substrate stage 15, the diamond can always be kept in the optimal growth temperature range, reducing the occurrence of polycrystallineization and graphitization on the diamond crystal surface and improving the yield.

[0056] An infrared thermometer for detecting temperature is installed inside the reaction chamber 3. The infrared thermometer acquires the temperature of the upper surface of the substrate stage 15 inside the reaction chamber 3. Based on the acquired temperature, the lifting assembly is controlled to move the heat sink 18 closer to and away from the substrate stage 15. For example, when the temperature of the upper surface of the substrate stage 15 is high, the lifting assembly is controlled to move the heat sink 18 closer to the substrate stage 15.

[0057] In some embodiments, the lifting assembly includes an inner heat dissipation column 19, an outer heat dissipation column 20, and a first flexible tube 21 (e.g., a corrugated tube). The outer heat dissipation column 20 is sleeved on the outside of the inner heat dissipation column 19 and can slide axially relative to the inner heat dissipation column 19. The outer heat dissipation column 20 is connected to a support assembly, for example, the top of the outer heat dissipation column 20 is connected to the metal platform 11 by screws and sealed with an O-ring (or further, it can be welded). The upper part of the inner heat dissipation column 19 is connected to the heat dissipation platform 18. One end of the first flexible tube 21 is sealed to the bottom of the outer heat dissipation column 20 by an O-ring, and the other end is sealed to the lower side of the inner heat dissipation column 19 by an O-ring, thereby achieving a seal between the inner heat dissipation column 19 and the outer heat dissipation column 20. The lower parts of both the inner heat dissipation column 19 and the outer heat dissipation column 20 can be fixed on the frame. When the heat dissipation platform 18 is lifted, the motor system drives the inner heat dissipation column 19 to move axially relative to the outer heat dissipation column 20, so that the heat dissipation platform 18 moves closer to and further away from the substrate platform 15.

[0058] A second flexible tube 22, such as a corrugated pipe, is provided on the outer wall of the external heat dissipation column 20. A flange 23 is fitted on the outer side of the external heat dissipation column 20. The flange 23 can be axially displaced relative to the external heat dissipation column 20 for sealing connection to the bottom of the reaction chamber 3. One end of the second flexible tube 22 is sealed to the outer wall of the external heat dissipation column 20, and the other end is connected to the flange 23 and sealed to the bottom of the reaction chamber 3 through an O-ring or other structure, so as to seal the upper structure of the substrate stage system inside the reaction chamber 3.

[0059] A first heat dissipation channel 17 is provided within the inner heat dissipation column 19 and the heat dissipation platform 18. A heat dissipation medium (e.g., cold water or cold air) is provided within the first heat dissipation channel 17. The first heat dissipation channel 17 is located both within the inner heat dissipation column 19 and the heat dissipation platform 18 to facilitate heat conduction between them. The inlet 191 and outlet 192 of the first heat dissipation channel 17 are located on the inner heat dissipation column 19 away from the heat dissipation platform 18 to facilitate the entry and exit of the heat dissipation medium. A second heat dissipation channel is provided within the outer heat dissipation column 20. A heat dissipation medium (e.g., cold water or cold air) is provided within the second heat dissipation channel. The inlet 201 and outlet of the second heat dissipation channel are located on the outer heat dissipation column 20 away from the supporting components to facilitate the entry and exit of the heat dissipation medium.

[0060] This application provides an MPCVD device, including a reaction chamber and a substrate stage system disposed within the reaction chamber. This substrate stage system is the same as the one described in the above embodiments. With this configuration, the design of the first, second, and third heat dissipation sections on the heat dissipation stage allows for non-uniform compensated radiative heat dissipation in different areas of the substrate stage. This effectively balances the radial temperature gradient on the upper surface of the substrate stage, ensuring a consistent diamond growth rate, reducing diamond crystal stress, and decreasing the cracking rate.

[0061] As shown in Figure 9, the MPCVD equipment includes: a substrate stage system 1 (mainly used to support the diamond substrate and provide heat dissipation for the diamond substrate during the growth process), a reaction chamber 3, a quartz dielectric window 4, a mode conversion chamber 5, an antenna 6, a mode converter 7, three pins 8, and a microwave generator 9. Microwave generator 9 emits TE mode microwaves at a frequency of 2.45 GHz. The TE (transverse electric) mode microwaves are transmitted through waveguides into three pins 8. The phase of the microwaves can be adjusted by moving the three pins 8. After passing through the three pins 8, the TE mode microwaves enter the mode conversion cavity 5. The antenna 6 in the mode conversion cavity 5 can convert the TE mode wave into a TEM (transmission line) mode wave. The TEM mode microwaves enter the reaction chamber 3 through the quartz dielectric window 4. The TEM mode microwaves can generate a resonant electric field inside the reaction chamber 3. When the pressure inside the reaction chamber 3 is appropriate, the strong electric field can ionize the reaction gas inside the reaction chamber and generate plasma 2 above the substrate stage. The carbon-containing groups in plasma 2 will diffuse onto the diamond substrate within a suitable temperature range, realizing the homoepitaxial growth of diamond.

[0062] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. In addition, the specific details disclosed above are only for illustrative and facilitative purposes, and are not limitations. The above details do not limit this application from having to adopt the above specific details for implementation.

[0063] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0064] It should also be noted that in the apparatus, equipment and methods of this application, each component or step can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0065] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0066] It should be understood that the qualifying terms “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and cannot be used to limit the scope of protection of this application.

[0067] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof. [Simplified Explanation of the Diagram]

[0024] In order to more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort. Figure 1 is a partial cross-sectional view of a substrate stage system shown in some embodiments; Figure 2 is a partial enlarged view of Figure 1; Figure 3 is a partial exploded view of a support assembly shown in some embodiments; Figure 4 is a perspective view of a retainer shown in some embodiments; Figure 5 is a cross-sectional view of a substrate stage shown in some embodiments; Figure 6A is a cross-sectional view of a heat sink shown in some embodiments; Figure 6B is another cross-sectional view of a heat sink shown in some embodiments; Figure 7 is a top perspective cross-sectional view of a substrate stage system shown in some embodiments; Figure 8 is a bottom perspective cross-sectional view of a substrate stage system shown in some embodiments; Figure 9 is a structural diagram of an MPCVD apparatus shown in some embodiments; Figure 10 is an electric field simulation diagram without an annular protrusion; Figure 11 is an electric field simulation diagram with an annular protrusion; Figure 12 is a comparison diagram of electric field simulation results shown in some embodiments.

Claims

1. A substrate stage system, wherein, include: A microwave reflector and a large molybdenum stage stacked together; A substrate stage is disposed on the side of the large molybdenum stage away from the microwave reflector stage; wherein, an annular protrusion is provided on the side of the large molybdenum stage away from the microwave reflector stage, the annular protrusion being coaxial with the substrate stage and surrounding the outer periphery of the substrate stage.

2. The substrate stage system according to claim 1, wherein, The annular protrusion is spaced apart from the substrate stage; and / or, the surface of the annular protrusion on the side away from the large molybdenum stage is lower than the surface of the substrate stage on the side away from the large molybdenum stage.

3. The substrate stage system according to claim 1, wherein, The annular protrusion is perpendicular to the inner circumferential surface of the substrate stage and the side of the large molybdenum stage away from the microwave reflector stage, and the side of the annular protrusion away from the substrate stage is set as an arc surface.

4. The substrate stage system according to claim 1, wherein, A retainer is provided on the side of the large molybdenum stage away from the microwave reflector stage. The retainer surrounds the outer periphery of the substrate stage to position the substrate stage. The annular protrusion is provided around the outer periphery of the retainer.

5. The substrate stage system according to claim 4, wherein, The outer peripheral surface of the substrate stage contacts the cage through a first contact structure, which is configured as a line contact structure or a point contact structure for contacting the substrate stage.

6. The substrate stage system according to claim 5, wherein, The first contact structure includes a plurality of first pointed protrusions disposed inside the retainer, the plurality of first pointed protrusions being distributed circumferentially along the substrate stage, and the tips of the first pointed protrusions abutting against the outer peripheral surface of the substrate stage.

7. The substrate stage system according to claim 1, wherein, The large molybdenum stage is arranged in a ring shape, and the side of the substrate stage facing the large molybdenum stage abuts against the large molybdenum stage.

8. The substrate stage system according to claim 7, wherein, The substrate stage has a second contact structure on the side facing the large molybdenum stage. The substrate stage contacts the large molybdenum stage through the second contact structure. The second contact structure is configured as a line contact structure or a point contact structure for contacting the large molybdenum stage.

9. The substrate stage system according to claim 8, wherein, The second contact structure includes a second pointed protrusion disposed on the side of the substrate stage facing the large molybdenum stage and located at the edge of the substrate stage, the tip of the second pointed protrusion abutting against the surface of the large molybdenum stage away from the microwave reflector.

10. The substrate stage system according to claim 1, wherein, The microwave reflector has a first positioning protrusion on the side near the large molybdenum stage, which surrounds the outer periphery of the large molybdenum stage and can position the large molybdenum stage; a metal stage is provided on the side of the microwave reflector away from the large molybdenum stage, and a second positioning protrusion is provided on the side of the microwave reflector away from the large molybdenum stage, which surrounds the outer periphery of the metal stage and can position the metal stage.

11. The substrate stage system according to claim 1, wherein, It also includes: a heat sink; both the large molybdenum stage and the microwave reflector stage are arranged in a ring shape and surround the outer periphery of the heat sink, with a gap between the substrate stage and the heat sink to allow the heat sink to radiate heat to the substrate stage; wherein, on the side of the heat sink near the substrate stage, multiple heat dissipation sections are formed sequentially from the center to the edge, and the heat dissipation coefficient of the heat dissipation section located in the center and edge of the heat sink is greater than that of the heat dissipation section located between the center and edge of the heat sink, so as to compensate for the temperature of the substrate stage through non-uniform heat dissipation.

12. The substrate stage system according to claim 11, wherein, The multiple heat dissipation parts are made of the same material, and the surface roughness of the heat dissipation parts located in the middle and edge of the heat dissipation platform is greater than that of the heat dissipation parts located between the middle and edge of the heat dissipation platform.

13. The substrate stage system according to claim 11, wherein, The multiple heat dissipation parts are made of different materials, and the surface emissivity of the heat dissipation parts located in the middle and edge of the heat dissipation platform is greater than that of the heat dissipation parts located between the middle and edge of the heat dissipation platform.

14. The substrate stage system according to claim 11, wherein, A radiative heat dissipation layer is provided on the side of the heat sink near the substrate stage. The radius of the radiative heat dissipation layer is smaller than the radius of the heat sink, so that the plurality of heat dissipation parts are sequentially formed from the center to the edge on the surface of the radiative heat dissipation layer and the side of the heat sink near the substrate stage.

15. The substrate stage system according to claim 14, wherein, All of the heat dissipation components are made of oxygen-free copper. The surface roughness of the middle part of the radiative heat dissipation layer is set to 1.6 micrometers-3.2 micrometers, the surface roughness of the edge of the radiative heat dissipation layer is set to 0.3 micrometers-1.2 micrometers, and the surface roughness of the edge of the heat dissipation platform is set to 0.1 micrometers-0.6 micrometers.

16. The substrate stage system according to claim 11, wherein, It also includes: a lifting assembly connected to the heat sink, the lifting assembly being used to move the heat sink axially closer to or further away from the substrate stage.

17. An MPCVD apparatus, wherein, Includes a reaction chamber and a substrate stage system as described in any one of claims 1-16 disposed within the reaction chamber.

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