Microwave plasma chemical vapor deposition system

Abstract

The microwave plasma chemical vapor deposition system comprises a microwave resonant cavity used for growth of diamond; the adjusting mechanism is arranged outside the microwave resonant cavity and is used for adjusting the size of the microwave resonant cavity; the device is characterized in that a lower cavity is arranged outside the microwave resonant cavity, the adjusting mechanism comprises a driving source and an adjusting part, correspondingly, the lower cavity is provided with an opening, and the opening is provided with a first sealing assembly; one wall part of the lower cavity is also provided with a mounting channel; and the mounting channel is provided with a second sealing assembly. According to the technical scheme, the connecting part of the driving source and the outer wall of the lower cavity is omitted, air leakage points are reduced, and the sealing performance of the lower cavity is enhanced; and the electricity taking device is used for external power supply access, and the second sealing assembly is arranged, so that the sealing performance of the mounting channel is ensured, the electricity taking device is not in direct contact with the mounting channel, and a certain buffering effect is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical vapor deposition processes using microwave discharge, and particularly to a microwave plasma chemical vapor deposition system. Background Art

[0002] Currently, in traditional microwave plasma chemical vapor deposition systems (hereinafter referred to as MPCVD) for growing diamond, the substrates for growing diamond are all fixed. As the diamond grows and thickens continuously, the distance between the diamond surface and the plasma becomes closer and closer, resulting in too high a temperature of the diamond. Therefore, in the actual application process, in order to obtain better diamond deposition quality, the operator needs to stop the machine to take out the diamond after the diamond grows to a certain thickness, replace the molybdenum substrate with a deeper slot to increase the distance between the diamond surface and the plasma, and then restart the machine for the next growth process; several replacement operations as described above are required in one growth cycle of the diamond, which is time-consuming, laborious and costly, and at the same time, the change of the microscopic growth environment due to several growths also leads to unstable diamond quality and a decrease in the yield rate.

[0003] In view of the above problems, in the prior art, a Chinese utility model patent "A Cavity Structure for MPCVD Equipment" with the patent number ZL202223096111.6 (publication number CN218860884U) discloses an MPCVD equipment with a lifting device. The lifting device in it uses a lead screw and a servo motor, and a gear driven by a rack and an external motor to control the lifting movement of the growth substrate in the reaction cavity, and a knife-edge seal is used at the connection between the lifting device and the lower cavity to increase the overall sealing performance of the equipment. This type of patent enables the operator to adjust the distance between the diamond surface and the plasma without stopping the operation of the MPCVD equipment through the setting of the lifting device; however, the driving motors of this type of patent are all arranged outside the cavity, which makes the gap at the connection between the motor and the lower cavity become larger with the vibration of the motor, affecting the sealing performance of the lower cavity. Summary of the Utility Model

[0004] The technical problem to be solved by the utility model is to provide a microwave plasma chemical vapor deposition system that can avoid poor cavity tightness caused by the external arrangement of the driving motor in view of the above-mentioned prior art situation.

[0005] The technical solution adopted by the utility model to solve the above technical problems is as follows: The microwave plasma chemical vapor deposition system includes:

[0006] A microwave resonant cavity for growing diamond;

[0007] An adjusting mechanism arranged outside the microwave resonant cavity for adjusting the volume of the microwave resonant cavity.

[0008] It is characterized in that:

[0009] A lower chamber is provided outside the microwave resonant cavity. The adjusting mechanism includes a driving source and an adjusting part for changing the volume of the microwave resonant cavity. Correspondingly, the lower chamber is provided with an opening for the driving source to be put into from the outside, and the opening is provided with a first sealing component; an installation channel is also opened on one of the wall parts of the lower chamber, and the installation channel is provided with a second sealing component, so that a current collector for connecting an external power supply to the driving source can be hermetically connected to the installation channel.

[0010] In order to make the installation of the current collector stable, further, the second sealing component includes a main body part, an upper flange part and a lower flange part that horizontally extend outward from the outer peripheral surface of the main body part and are annular. A clamping space is formed between the upper flange part and the lower flange part. The main body part has a central hole for the power cord of the current collector to pass through. A central surrounding area communicated with the central hole is provided at the center of the upper flange part, and the current collector is accommodated in the central surrounding area, while the periphery of the installation channel corresponding to the installation opening is clamped in the clamping space formed between the upper flange part and the lower flange part. The upper flange part and the lower flange part enable the second sealing component to fit tightly with the inner wall and the outer wall of the installation channel, and the installation is stable; the clamping space formed between the upper flange part and the lower flange part of the main body part enables it to be hermetically connected with the periphery of the installation opening of the installation channel, and can effectively prevent the problem of poor airtightness of the installation channel caused by the installation gap between the two. In addition, the central surrounding area located at the center of the upper flange part can independently accommodate the current collector and also play a corresponding sealing role to avoid friction with the wall part of the lower chamber.

[0011] In order to reduce the vibration directly conducted by the driving source to the installation channel, further, the driving source is connected to the lower chamber by means of an installation bracket. The installation bracket includes a central hole located in the center for the driving source to pass through and at least two buffer members arranged at intervals along the circumference on the corresponding hole wall of the central hole.

[0012] In order to improve the buffering effect of the buffer member on the driving source, further, the buffer member has at least one hollow part, and the opening of the hollow part is exposed in the lower chamber. The vibration conducted to the inner wall of the installation channel via the buffer member can be offset by the deformation of the hollow part.

[0013] In order to enhance the sealing effect of the first sealing component, further, a lateral flange part is locally circumferentially outwardly protruded on the outer wall of the end of the opening connected to the first sealing component. The first sealing component includes:

[0014] A flange plate, the inner side of which is clamped with the opening and the lateral flange part;

[0015] A flange blind plate, arranged on the outer side of the flange;

[0016] The gasket is located between the flange and the blind flange plate. The flange, the gasket, the blind flange plate and the lateral flange portion are connected by bolts and nuts.

[0017] In order to enhance the airtightness of the microwave resonance cavity, further, a growth base for diamond growth is provided in the microwave resonance cavity, a support column connected to the growth base is provided under the growth base for supporting the growth base, and the adjustment part includes:

[0018] A partition plate, forming a bottom wall of the microwave resonance cavity, wherein the support column passes through the partition plate and partially extends into the microwave resonance cavity;

[0019] a third sealing member, used for sealing the gap between the support column and the partition plate;

[0020] The driven component has one end connected to the lower end of the third sealing member and at least partially sleeved on the outer periphery of the support column, and the other end connected to the driving source, and the driving source drives the driven component to move up and down along the support column. The third sealing member prevents the gas in the microwave resonance cavity from leaking from the gap when the partition plate moves up and down, thereby avoiding carbon deposition on the support column and the driven component.

[0021] In order to reduce the number of air leakage points in the lower chamber, further, the driven component includes:

[0022] A cylindrical sleeve is vertically arranged in the lower chamber, the upper end of which is detachably connected to the third sealing member, and the lower end of which is located in the lower chamber, and the outer wall of the cylindrical sleeve partially protrudes outward to form a rack portion;

[0023] A driving gear, located in the lower chamber and meshing with the rack portion, the driving gear being adapted to the rack portion;

[0024] The reducer has one end connected to the driving gear and the other end connected to the output end of the driving source, and is used to control the rotation angle of the driving gear. The advantage of the cylindrical sleeve being arranged in the lower chamber is that it avoids the leakage phenomenon when the lower end of the cylindrical sleeve moves relative to the bottom wall of the lower chamber during the descent process, and also reduces the friction between the cylindrical sleeve seat and the bottom wall of the lower chamber during the lifting movement, thereby reducing the output power of the driving source.

[0025] Compared with the prior art, the advantages of the utility model are:

[0026] 1. The solution in which the driving source is arranged inside the lower chamber saves the connection part between the driving source and the outer wall of the lower chamber, reduces the leakage points, and enhances the sealing of the lower chamber;

[0027] 2. The use of a current collector as the external power supply connection and the setting of the second sealing component avoid the direct contact between the drive source and the installation channel, reducing the vibration amplitude transmitted from the drive source to the installation channel. Moreover, the current collector is connected to the installation channel through the second sealing component, which not only ensures the sealing of the installation channel but also prevents the current collector from directly contacting the installation channel, reducing the external force acting when the current collector accesses the power supply and the impact of the vibration transmitted from the drive source to the current collector on the sealing of the installation channel. Therefore, it also has a certain buffering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic structural diagram of an embodiment of the present invention;

[0029] Figure 2 It is a longitudinal sectional view of an embodiment of the present invention;

[0030] Figure 3 It is an exploded view of the structure of an embodiment of the present invention;

[0031] Figure 4 It is a longitudinal sectional view of another perspective of an embodiment of the present invention;

[0032] Figure 5 It is a schematic structural diagram of the second sealing component of an embodiment of the present invention;

[0033] Figure 6 It is a schematic structural diagram of the first sealing component of an embodiment of the present invention;

[0034] Figure 7 It is a longitudinal sectional view of another depth of an embodiment of the present invention;

[0035] Figure 8 It is a schematic structural diagram of the adjustment part of an embodiment of the present invention;

[0036] Figure 9 It is a schematic structural diagram of the driven component of an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0037] The present invention will be further described in detail below in conjunction with the embodiments of the drawings.

[0038] Such as Figures 1 to 9As shown, it is the best embodiment of the present utility model. The microwave plasma chemical vapor deposition system of this embodiment is mainly used for growing diamond. During the diamond growth process, it is necessary to keep a certain distance from the plasma to prevent the surface temperature of the diamond from being too high. Therefore, a lower chamber is provided under the resonant cavity to install a lifting mechanism, and the distance between the diamond and the plasma is indirectly adjusted by controlling the size of the resonant cavity. The lifting mechanism requires a driving source to control the lifting. Currently, the driving sources are all arranged outside the lower chamber and are flange-connected. The driving source is generally a motor, and while the motor outputs power, it will generate vibrations itself. These vibrations are conducted along the flange to each connection part of the MPCVD equipment, resulting in a poor sealing performance of the resonant cavity. Therefore, it will be beneficial to provide a microwave plasma chemical vapor deposition system that can avoid the poor airtightness of the cavity caused by the external placement of the driving motor. The following will elaborate on the detailed structure of this microwave plasma chemical vapor deposition system:

[0039] Refer to Figure 1 and Figure 2 , this microwave plasma chemical vapor deposition system includes a microwave resonant cavity 1 for growing diamond, an adjusting mechanism 2 for adjusting the volume of the microwave resonant cavity 1, and a lower chamber 3. Among them, the adjusting mechanism 2 is arranged outside the microwave resonant cavity 1, and a lower chamber 3 is provided outside the microwave resonant cavity 1. The adjusting mechanism 2 includes a driving source 21 and an adjusting part 22 for changing the volume of the microwave resonant cavity 1. Correspondingly, the lower chamber 3 is provided with an opening 30 for the driving source 21 to be placed in from the outside, and the opening 30 is provided with a first sealing component 4; one of the wall parts of the lower chamber 3 is also provided with an installation channel 31, and the installation channel 31 is provided with a second sealing component 5, so that a current collector 6 for connecting an external power supply to the driving source 21 can be hermetically connected to the installation channel 31. A material taking window for taking out diamond is also provided on the microwave resonant cavity 1.

[0040] Refer to Figure 5, the second sealing assembly 5 includes a main body portion 51, an upper flange portion 52 and a lower flange portion 53 which horizontally extend outward from the outer peripheral surface of the main body portion 51 and are annular. A clamping space 54 is formed between the upper flange portion 52 and the lower flange portion 53. The main body portion 51 has a central hole 511 through which the power cord of the current collector 6 passes. A central surrounding area 521 communicating with the central hole 511 is provided at the center of the upper flange portion 52. The central surrounding area 521 is for accommodating the current collector 6, and the periphery of the installation passage 31 corresponding to the installation port 311 is clamped in the clamping space 54 formed between the upper flange portion 52 and the lower flange portion 53. The clamping space 54 enables the second sealing assembly 5 to be stably connected to the installation passage 31, thereby enabling the current collector 6 to be stably installed. The upper flange portion 52 and the lower flange portion 53 enable the second sealing assembly 5 to closely fit the inner wall and the outer wall of the installation passage 31, and the installation is stable; the clamping space 54 formed between the upper flange portion 52 and the lower flange portion 53 of the main body portion 51 enables it to be hermetically connected to the periphery of the installation passage 31 corresponding to the installation port 311, effectively preventing the problem of poor airtightness of the installation passage 31 due to the installation gap between the two. In addition, the central surrounding area 521 located at the center of the upper flange portion 52 can independently accommodate the current collector 6 and also plays a corresponding sealing role, avoiding friction with the wall portion of the lower chamber 3.

[0041] See Figures 2 to 4 , the drive source 21 is connected to the lower chamber 3 by means of a mounting bracket 23. The mounting bracket 23 includes a central hole 231 located in the center for the drive source 21 to pass through and at least two buffer members 232 circumferentially spaced apart on the corresponding hole walls of the central hole 231, reducing the vibration directly transmitted from the drive source 21 to the installation passage 31. The number of buffer members 232 is preferably 4. The buffer member 232 has at least one hollow portion 230. Preferably, each buffer member 232 has two hollow portions 230, and the openings of the hollow portions 230 are exposed to the lower chamber 3. Part of the vibration transmitted to the inner wall of the installation passage 31 via the buffer member 232 can be offset by the deformation of the hollow portion 230, improving the buffering effect of the buffer member 232 on the drive source 21.

[0042] See Figure 6 and Figure 7 , a lateral flange portion 301 is locally circumferentially outwardly convex on the outer wall of one end of the opening 30 connected to the first sealing assembly 4. The first sealing assembly 4 includes a flange plate 41, a flange blind plate 42 and a gasket 43. Among them, the inner side of the flange plate 41 is clamped with the opening 30 and the lateral flange portion 301; the flange blind plate 42 is provided on the outer side of the flange plate 41; the gasket 43 is located between the flange plate 41 and the flange blind plate 42. The flange plate 41, the gasket 43, the flange blind plate 42 and the lateral flange portion 301 are connected by bolts and nuts, enhancing the sealing effect of the first sealing assembly 4.

[0043] SeeFigure 7 and Figure 8 In the microwave resonant cavity 1, there is a growth base 8 for diamond growth. Below the growth base 8, there are support columns 9 connected to the growth base 8 for supporting the growth base 8. The adjustment part 22 includes a partition plate 221, a third seal 222 and a driven assembly 223. Among them, the partition plate 221 forms the bottom wall of the microwave resonant cavity 1. The support column 9 passes through the partition plate 221 and partially extends into the microwave resonant cavity 1. The third seal 222 is used to seal the gap 2211 between the support column 9 and the partition plate 221. One end of the driven assembly 223 is connected to the lower end of the third seal 222 and at least partially sleeved on the outer periphery of the support column 9, and the other end is connected to the drive source 21. The drive source 21 drives the driven assembly 223 to move up and down along the support column 9. The third seal 222 enables the gas in the microwave resonant cavity 1 not to leak from the gap 2211 during the up and down movement, thereby avoiding carbon deposition on the support column 9 and the driven assembly 233, and enhancing the airtightness of the microwave resonant cavity 1.

[0044] See Figure 9 , the driven assembly 223 includes a cylindrical sleeve 2231, a drive gear 2232 and a speed reducer 2233. Among them, the cylindrical sleeve 2231 is vertically arranged in the lower chamber 3. The upper end is detachably connected to the third seal 222, and the lower end is located in the lower chamber 3. A rack portion 2230 is formed by locally protruding the outer wall of the cylindrical sleeve 2231. The drive gear 2232 is located in the lower chamber 3 and meshes with the rack portion 2230, and the drive gear 2232 is adapted to the rack portion 2230. One end of the speed reducer 2233 is connected to the drive gear 2232 and the other end is connected to the output end of the drive source 21 for controlling the rotation angle of the drive gear 2232. The advantage of arranging the cylindrical sleeve 2231 in the lower chamber 3 is that it avoids air leakage when the lower end of the cylindrical sleeve 2231 moves relative to the bottom wall of the lower chamber 3 during the descending process. At the same time, it also reduces the friction between the cylindrical sleeve 2231 and the bottom wall of the lower chamber 3 during the up and down movement, reduces the output power of the drive source 21, and also reduces the number of air leakage points in the lower chamber 3.

[0045] The working principle of the microwave plasma chemical vapor deposition system in this embodiment is as follows: The operator first places a diamond substrate on the growth stage 8, turns on the MPCVD equipment and introduces the growth gas; after a period of time, a certain thickness of diamond grows on the diamond substrate. An external power supply is connected through the electrical connector 6, and the driving source 21 drives the speed reducer 2233. The output end of the speed reducer 2233 controls the rotation of the driving gear 2232, thereby driving the cylindrical sleeve 2231 and the partition plate 221 to move downward, further increasing the distance between the diamond surface and the plasma. During the diamond growth process, the operator should frequently connect to the external power supply as the thickness of the diamond increases to control the distance between the diamond surface and the plasma to be appropriate. After the diamond growth is completed, the external power supply is connected. At this time, the voltage direction is reversed, driving the partition plate 221 to move upward to the position before the diamond substrate is placed, and the operator takes out the diamond through the material taking window.

Claims

1. A microwave plasma chemical vapor deposition system, comprising: A microwave resonant cavity (1) for the growth of diamond; An adjusting mechanism (2) arranged outside the microwave resonant cavity (1) for adjusting the volume of the microwave resonant cavity (1); It is characterized in that: A lower chamber (3) is provided outside the microwave resonant cavity (1). The adjusting mechanism (2) includes a driving source (21) and an adjusting part (22) for changing the volume of the microwave resonant cavity (1). Correspondingly, the lower chamber (3) is provided with an opening (30) for the driving source (21) to be put into it from the outside, and the opening (30) is provided with a first sealing component (4); One of the wall parts of the lower chamber (3) is also provided with an installation channel (31), and the installation channel (31) is provided with a second sealing component (5), so that a current collector (6) for connecting an external power supply to the driving source (21) can be hermetically connected to the installation channel (31).

2. The microwave plasma chemical vapor deposition system according to claim 1, wherein: The second sealing component (5) includes a main body part (51), and an upper flange part (52) and a lower flange part (53) that horizontally extend outward from the outer peripheral surface of the main body part (51) and are annular. A clamping space (54) is formed between the upper flange part (52) and the lower flange part (53). The main body part (51) has a central hole (511) for the power cord of the current collector (6) to pass through. The center of the upper flange part (52) is provided with a central surrounding area (521) communicating with the central hole (511), and the current collector (6) is accommodated in the central surrounding area (521). The periphery of the installation channel (31) corresponding to the installation port (311) is clamped in the clamping space (54) formed between the upper flange part (52) and the lower flange part (53).

3. The microwave plasma chemical vapor deposition system according to claim 2, characterized in that: The driving source (21) is connected to the lower chamber (3) by means of a mounting bracket (23). The mounting bracket (23) includes a central hole (231) located in the center for the driving source (21) to pass through and at least two buffer members (232) arranged at intervals along the circumferential direction on the corresponding hole walls of the central hole (231).

4. The microwave plasma chemical vapor deposition system according to claim 3, wherein: The buffer member (232) has at least one hollow part (230), and the opening of the hollow part (230) is exposed in the lower chamber (3).

5. The microwave plasma chemical vapor deposition system according to any one of claims 1 to 4, characterized in that: The outer wall of one end of the opening (30) connected to the first sealing component (4) bulges outward locally in the circumferential direction to form a lateral flange part (301). The first sealing component (4) includes: A flange plate (41) whose inner side is clamped with the opening (30) and the lateral flange part (301); A flange blind plate (42) arranged on the outer side of the flange plate (41); A gasket (43) located between the flange plate (41) and the flange blind plate (42). The flange plate (41), the gasket (43), the flange blind plate (42) and the lateral flange part (301) are connected by bolts and nuts.

6. The microwave plasma chemical vapor deposition system according to any one of claims 1 to 4, characterized in that: The microwave resonant cavity (1) is internally provided with a growth pedestal (8) for diamond growth. A support column (9) connected to the growth pedestal (8) is provided under the growth pedestal (8) for supporting the growth pedestal (8). The adjusting part (22) includes: A partition plate (221) forms the bottom wall of the microwave resonant cavity (1). The support column (9) passes through the partition plate (221) and partially extends into the microwave resonant cavity (1). A third seal (222) is used to seal the gap (2211) between the support column (9) and the partition plate (221). A driven assembly (223), one end of which is connected to the lower end of the third seal (222) and at least partially sleeved on the outer periphery of the support column (9), and the other end is connected to the drive source (21). The drive source (21) drives the driven assembly (223) to move up and down along the support column (9).

7. The microwave plasma chemical vapor deposition system according to claim 6, wherein The driven assembly (223) includes: A cylindrical sleeve (2231) is vertically arranged in the lower chamber (3). The upper end is detachably connected to the third seal (222), and the lower end is located in the lower chamber (3). A rack portion (2230) is formed by partial outward protrusion of the outer wall of the cylindrical sleeve (2231). A drive gear (2232) is located in the lower chamber (3) and meshes with the rack portion (2230). The drive gear (2232) is adapted to the rack portion (2230). A speed reducer (2233), one end of which is connected to the drive gear (2232) and the other end is connected to the output end of the drive source (21), for controlling the rotation angle of the drive gear (2232).

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