Method for improving coating quality

Abstract

The present invention provides a method for improving the coating quality, belonging to the field of microwave technology. The above-mentioned deposition equipment includes a frame, a cavity, a sample stage and a lifting drive device. The frame includes a discharge cavity bottom plate. The bottom of the cavity is connected to the upper part of the discharge cavity bottom plate and encloses to form a discharge cavity. The sample stage is arranged in the discharge cavity. A lifting rod is arranged at the bottom of the sample stage. An installation hole is arranged on the discharge cavity bottom plate, and the lifting rod can slide through the installation hole. The lifting drive device is connected to the bottom of the lifting rod and is used to drive the lifting rod to drive the sample stage to move up and down. The above-mentioned method uses the above-mentioned deposition equipment. By moving the sample stage up and down a certain distance, the electromagnetic field distribution can be improved, making the plasma sphere flatter, and further enabling the coating thickness to be more uniform and improving the coating quality.

Description

Technical Field

[0001] The present invention relates to the field of microwave plasma chemical vapor deposition equipment, and more particularly to a method for improving the coating quality. Background Art

[0002] The microwave plasma chemical vapor deposition technology is to introduce the microwave generated by a microwave generator into the cavity of the reactor through a waveguide via an isolator, and introduce a mixed gas of methane and hydrogen into the cavity. Under the excitation of the microwave, discharge occurs in the cavity chamber, ionizing the molecules of the reaction gas to generate plasma. A sample stage is arranged in the cavity, and a substrate is arranged on the sample stage. After the reaction gas molecules are ionized, carbon elements will be deposited on the substrate to form a diamond coating. The uniformity of the diamond coating thickness is one of the important indicators of the coating quality. In the current deposition equipment, the coating thickness is not uniform enough, resulting in poor coating quality. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for improving the coating quality, which can significantly improve the coating quality.

[0004] The present invention is implemented as follows:

[0005] A microwave plasma chemical vapor deposition equipment, comprising:

[0006] A frame, the frame includes a discharge cavity bottom plate;

[0007] A cavity, the bottom of the cavity is connected to the upper part of the discharge cavity bottom plate and encloses to form a discharge cavity;

[0008] A sample stage, the sample stage is arranged in the discharge cavity, a lifting rod is arranged at the bottom of the sample stage, and an installation hole is arranged on the discharge cavity bottom plate, and the lifting rod can slide through the installation hole;

[0009] A lifting drive device, the lifting drive device is connected to the bottom of the lifting rod and is used to drive the lifting rod to drive the sample stage to move up and down.

[0010] Further, the lifting drive device includes a motor and a transmission component, and the motor is connected to the lifting rod through the transmission component and is used to drive the lifting rod to move up and down.

[0011] Further, the transmission component includes a lifting plate and a plurality of lead screws, and the lifting plate is fixedly connected to the lifting rod;

[0012] The multiple lead screws are all vertically arranged and rotatably connected to the frame, and the axial movement of the multiple lead screws is restricted; a nut is sleeved on each lead screw, and the multiple nuts are fixedly connected to the lifting plate; the motor is in transmission connection with the multiple lead screws and can drive the multiple lead screws to rotate synchronously.

[0013] Further, a connecting plate is further included, and the connecting plate is arranged between the bottom plate of the discharge chamber and the lifting plate, and the upper ends of the multiple lead screws are respectively rotatably connected to the connecting plate.

[0014] Further, a sleeve is arranged between the connecting plate and the bottom plate of the discharge chamber, and the sleeve is sleeved on the lifting rod. The upper end of the sleeve is fixedly connected to the bottom plate of the discharge chamber, and the lower end is fixedly connected to the connecting plate; the lifting rod movably passes through the connecting plate, and a sealing member is arranged between the lifting rod and the connecting plate; an air extraction hole is arranged on the sleeve.

[0015] Further, the lifting rod is swingably connected to the frame so that the inclination angle of the sample stage can be adjusted.

[0016] Further, a moving block is fixedly connected to the lower part of the lifting rod, and the moving block is arranged on the lifting plate;

[0017] Thrust blocks are arranged around the moving block, and the thrust blocks are fixedly connected to the lifting plate. A thrust screw is arranged on each thrust block; by rotating the thrust screw in the first direction, the thrust screw can be abutted against the moving block and can push the moving block to move. By rotating the thrust screw in the direction opposite to the first direction, the thrust screw can be separated from the moving block.

[0018] Further, an inner plate is further arranged in the discharge chamber, and the inner plate is in sliding fit with the inner wall of the cavity;

[0019] An inner bellows and an outer bellows are arranged between the inner plate and the bottom plate of the discharge chamber. The inner bellows is sleeved on the lifting rod, and the outer bellows is sleeved on the inner bellows; the upper ends of the inner bellows and the outer bellows are both hermetically connected to the inner plate, and the lower ends of the inner bellows and the outer bellows are both hermetically connected to the bottom plate of the discharge chamber. A containing space is formed between the inner bellows and the outer bellows;

[0020] An air extraction hole is arranged on the bottom plate of the discharge chamber, and the air extraction hole is communicated with the containing space for connecting an air extraction pipe.

[0021] Further, shaping telescopic tubes are arranged on the inner sides and the outer sides of the inner bellows and the outer bellows for reducing the radial deformation amount of the inner bellows and the outer bellows.

[0022] A method for improving coating quality, which uses the described microwave plasma chemical vapor deposition equipment, includes the following steps:

[0023] Real-time detect the temperatures at the center point of the sample stage and in four directions at the edge;

[0024] When the temperature at the center position of the sample stage is higher than the average temperature at the edge position of the sample stage, increase the preset distance of the sample stage. After continuing to monitor for a preset time, when the temperature at the center position of the sample stage is still higher than the average temperature at the edge position of the sample stage, lower the height of the inner cavity plate;

[0025] The temperatures at two opposite positions at the edge of the sample stage are the first temperature and the second temperature respectively. When the difference between the first temperature and the second temperature is greater than the preset difference, adjust the tilt angle of the sample stage so that the position corresponding to the lower temperature among the first temperature and the second temperature of the sample stage moves a preset distance away from the plasma sphere.

[0026] The beneficial effects of the present invention are:

[0027] The method for improving coating quality obtained by the above design of the present invention, when in use, when the temperature measuring instrument measures that the temperature at the center of the sample stage is higher than the average temperature at the edge, it indicates that the temperature at the center of the sample stage is too high. The inventor has found through research that when the temperature at the center of the sample stage is too high, it means that the plasma sphere is not flat enough, that is, the central electromagnetic field is too strong and the edge is relatively weak; the electromagnetic field distribution is one of the important factors affecting the coating thickness uniformity. At this time, moving the sample stage upward by a certain distance can improve the electromagnetic field distribution, make the plasma sphere more flat, and thus make the coating thickness more uniform and improve the coating quality. Description of the Drawings

[0028] Figure 1 is a cross-sectional view of the deposition equipment provided by the embodiment of the present invention;

[0029] Figure 2 is a three-dimensional view of the deposition equipment provided by the embodiment of the present invention;

[0030] Figure 3 is a top view of the sample stage of the deposition equipment provided by the embodiment of the present invention;

[0031] Figure 4 is a curve graph showing the change of the temperature at the edge position of the sample stage with the distance between the edge position of the sample stage and the plasma sphere when the deposition equipment provided by the embodiment of the present invention is working.

[0032] Icons: 1 - Deposition equipment; 11 - Chamber; 121 - Discharge chamber bottom plate; 1211 - Air extraction hole; 122 - Connection plate; 13 - Sample stage; 14 - Lifting rod; 15 - Lifting drive device; 151 - Motor; 152 - Lifting plate; 153 - Lead screw; 154 - Nut; 155 - Belt; 16 - Sleeve; 17 - Moving block; 18 - Pushing block; 181 - Pushing screw; 191 - Inner chamber plate; 192 - Inner bellows; 193 - Outer bellows; 194 - Shaped telescopic tube; 2 - Plasma sphere. Detailed implementation manners Embodiment

[0033] Please refer to Figures 1-3 , this embodiment provides a microwave plasma chemical vapor deposition equipment 1, which includes a frame, a chamber 11 and a sample stage 13. Among them, the chamber 11 is fixedly installed on the discharge chamber bottom plate 121 of the frame, and the sample stage 13 is arranged in the chamber 11. During discharge, the electromagnetic field is mainly distributed above the sample stage 13, and its shape is ellipsoidal, commonly known as the plasma sphere. Through research by the inventor, it is found that the flatter the plasma sphere is, the higher the film coating uniformity on the sample stage 13 is. The inventor further studies and discovers that the distance between the sample stage 13 and the plasma sphere can affect the flatness of the plasma sphere 2; that is, by adjusting the height of the sample stage 13, the flatness of the plasma sphere 2 can be adjusted.

[0034] In order to adjust the height of the sample stage 13, the deposition equipment 1 is also provided with a lifting drive device 15; the bottom of the sample stage 13 is connected to the lifting drive device 15 through a lifting rod 14. The lifting drive device 15 is used to drive the sample stage 13 to move up and down, so as to adjust the distribution of the electromagnetic field in the chamber 11 and make the plasma sphere 2 more flattened.

[0035] In addition, for the deposition equipment provided in this embodiment, the inclination angle between the sample stage 13 and the discharge chamber bottom plate 121 can also be adjusted. By adjusting the inclination angle of the sample stage 13, the distances between each position (position A, position B, position C, position D, position E) on the sample stage 13 and the plasma sphere 2 can be changed; thereby making the temperature distribution at each position on the sample stage 13 more uniform, and further improving the film coating quality.

[0036] Specifically, the chamber 11 is a cylindrical structure, and its bottom is fixedly connected to the discharge chamber bottom plate 121 of the frame; a discharge chamber is formed by enclosing between the chamber 11 and the discharge chamber bottom plate 121. An installation hole is provided in the middle of the discharge chamber bottom plate 121, and the outer diameter of the lifting rod 14 at the bottom of the sample stage 13 is smaller than the inner diameter of the above installation hole, so that the lifting rod 14 can move freely in the installation hole.

[0037] The lifting drive device 15 includes a motor 151 and a transmission assembly. The motor 151 is connected to the bottom of the lifting rod 14 through the transmission assembly, so as to be able to drive the lifting rod 14 to drive the sample stage 13 to move up and down together. The structural form of the transmission assembly is diverse; for example, in other embodiments, a rack can be provided on the lifting rod 14, and the motor 151 drives the rack to move up and down through a gear; or, the rotation of the lifting rod 14 around its own axis is restricted, a nut is sleeved on the lifting rod 14, and the axial movement of the nut is restricted, and the motor 151 is used to drive the nut to rotate. At this time, the lifting rod 14 can also move up and down.

[0038] For the deposition device 1 provided in this embodiment, not only does the sample stage 13 need to move up and down, but the included angle between the sample stage 13 and the bottom plate 121 of the discharge chamber (i.e., the tilt angle of the sample stage 13) also needs to be adjusted; therefore, the transmission assembly provided in this embodiment is different from the traditional structure.

[0039] In this embodiment, the transmission assembly includes a lifting plate 152 and four lead screws 153. Among them, a through hole is provided in the middle of the lifting plate 152, and the lifting rod 14 passes through the through hole in the middle of the lifting plate 152 and is fixedly connected to the lifting plate 152, so that the lifting rod 14 and the lifting plate 152 can move up and down synchronously. The four lead screws 153 are all vertically arranged and are respectively arranged around the lifting plate 152. The lead screws 153 are rotatably connected to the frame, and the bottoms of the four lead screws 153 are connected by a belt 155; the upper part of one of the lead screws 153 is in transmission connection with the motor 151; the motor 151 drives the above-mentioned lead screw 153 to rotate and drives the other lead screws 153 to rotate synchronously through the belt 155. A nut 154 is sleeved on the middle of the lead screw 153, and the nut 154 is fixedly connected to the lifting plate 152. The axial movement of the lead screw 153 is restricted. Therefore, when the lead screw 153 rotates under the drive of the motor 151, the nut 154 moves axially along the lead screw 153, and then drives the lifting plate 152 to move up and down.

[0040] Furthermore, the frame further includes a connecting plate 122. The connecting plate 122 is arranged between the bottom plate 121 of the discharge chamber and the lifting plate 152. The upper end of the lead screw 153 is rotatably connected to the connecting plate 122. A sleeve 16 is further arranged between the connecting plate 122 and the bottom plate 121 of the discharge chamber. The upper and lower ends of the sleeve 16 are respectively fixedly connected to the bottom plate 121 of the discharge chamber and the connecting plate 122. A through hole is provided in the middle of the connecting plate 122, and the lifting plate 152 is movably passed through the through hole in the middle of the connecting plate 122; and the connecting plate 122 and the lifting plate 152 are hermetically connected by a telescopic bellows. An air extraction hole is provided on the side wall of the sleeve 16, so as to facilitate the extraction of the air in the discharge chamber to form a vacuum discharge environment.

[0041] The upper part of the lifting rod 14 is swingably connected to the frame (directly or indirectly), so that the angle between the axis of the lifting rod 14 and the bottom plate 121 of the discharge chamber can be adjusted; when the lifting rod 14 swings, it can drive the sample stage 13 to swing, and then the tilt angle of the sample stage 13 changes accordingly.

[0042] In order to facilitate the adjustment of the angle between the sample stage 13 and the bottom plate 121 of the discharge chamber, a pushing component is provided at the bottom of the lifting rod 14. By moving the bottom plate of the lifting rod 14 in different directions, the adjustment of the tilt angle of the sample stage 13 is realized. Specifically, a moving block 17 is provided on the lifting plate 152, a through hole is provided in the middle of the moving block 17, the lifting rod 14 passes through the through hole and is fixedly connected to the moving block 17. Thrust blocks 18 are respectively arranged around the moving block 17. The thrust block 18 is of an L-shaped structure and is fixedly connected to the moving plate. A thrust screw 181 is provided on the thrust block 18. When one of the thrust screws 181 is rotated in the first direction, at this time the thrust screw 181 moves towards the moving block 17, and then it can abut against the moving block 17. Continuing to rotate the thrust screw 181, the thrust screw 181 can push the moving block 17 to move. When the thrust screw 181 is rotated in the direction opposite to the first direction, the thrust screw 181 moves away from the moving block 17.

[0043] In addition, the moving block 17 and the lifting plate 152 are also detachably connected by bolts. Specifically, a strip hole is provided on the lifting plate 152, and the strip hole extends along the radial direction of the lifting shaft; a bolt through hole is provided on the moving block 17, and the bolt passes through the bolt through hole and the strip hole; when it is necessary to adjust the tilt angle of the lifting rod 14 and the sample stage 13, loosen the bolt, push the moving block 17 to the preset position, and then tighten the bolt.

[0044] Furthermore, an inner chamber plate 191 is also provided in the discharge chamber. The inner chamber plate 191 is a circular plate, a through hole is provided in the middle thereof, and the outer edge is slidably matched with the inner wall of the cavity 11; the inner chamber plate 191 is located below the sample stage 13, and a swingable bearing is installed in the through hole of the inner chamber plate 191, and the lifting rod 14 passes through the inner ring of the bearing, so as to realize the swing of the lifting rod 14. In other embodiments, the lifting rod 14 can also be connected to the bottom plate 121 of the discharge chamber or the connecting plate 122 through a swingable bearing.

[0045] To adjust the distance between the inner cavity plate 191 and the sample stage 13, and further adjust the distribution of the electromagnetic field, an inner corrugated pipe 192 and an outer corrugated pipe 193 are provided between the inner cavity plate 191 and the bottom plate 121 of the discharge cavity. The inner corrugated pipe 192 is sleeved on the lifting rod 14, and the outer corrugated pipe 193 is sleeved on the inner corrugated pipe 192. The upper ends of the inner corrugated pipe 192 and the outer corrugated pipe 193 are hermetically connected to the inner cavity plate 191, and the lower ends of the inner corrugated pipe 192 and the outer corrugated pipe 193 are hermetically connected to the bottom plate 121 of the discharge cavity. A receiving space is formed between the inner corrugated pipe 192 and the outer corrugated pipe 193. An air extraction hole 1211 is provided on the bottom plate 121 of the discharge cavity, and the air extraction hole 1211 is communicated with the receiving space for connecting an air extraction pipe. By inflating or extracting air from the receiving space, the height of the inner cavity plate 191 can be adjusted.

[0046] In order to accurately control the lifting height of the inner cavity plate 191, the radial deformation amounts of the inner corrugated pipe 192 and the outer corrugated pipe 193 should be minimized; therefore, shaping telescopic pipes 194 are provided on both the inner and outer sides of the inner corrugated pipe 192 and the outer corrugated pipe 193. Embodiment

[0047] This embodiment provides a method for improving the coating quality, which uses the microwave plasma chemical vapor deposition device 1 provided in Embodiment 1; the method includes the following steps:

[0048] The temperatures at the central position A and the four edge positions B, C, D, and E of the sample stage 13 are detected in real time;

[0049] When the temperature at the central position of the sample stage 13 is higher than the average temperature at the edge positions of the sample stage 13, the sample stage 13 is raised by a preset distance, so that the sample stage 13 is closer to the plasma sphere, and thus the ellipsoidal plasma sphere becomes flatter. Compared with the original plasma sphere, the flatter plasma sphere has a lower central temperature and a higher edge temperature;

[0050] After continuing to monitor for a preset time, when the temperature at the central position of the sample stage 13 is still higher than the average temperature at the edge positions of the sample stage 13, the height of the inner cavity plate 191 is lowered. Appropriately lowering the height of the inner cavity plate 191 makes the distance between the inner cavity plate 191 and the sample stage 13 larger, and it can also make the ellipsoidal plasma sphere flatter. Compared with the original plasma sphere, the flatter plasma sphere has a lower central temperature and a higher edge temperature.

[0051] Please refer to Figure 4 , the edge temperature of the sample stage changes regularly with the distance between the edge position of the sample stage and the plasma sphere. At the beginning, the edge temperature increases with the increase of the distance. At this time, it corresponds to Figure 4 the first half of the temperature curve inFigure 4 The latter half of the medium temperature curve. When the microwave plasma chemical vapor deposition equipment is working properly, the distance between the edge position of its sample stage and the plasma sphere corresponds to Figure 4 the first half of the curve in

[0052] When the temperature difference between two positions opposite to the edge of the sample stage 13 is greater than a preset difference (for example, 50 °C), the tilt angle of the sample stage 13 is adjusted so that the side with the higher temperature of the sample stage 13 moves a preset distance towards the direction close to the plasma sphere, and the side with the lower temperature of the sample stage 13 moves a preset distance away from the plasma sphere. By adjusting the tilt angle of the sample stage 13, the distances between the above two opposite positions and the plasma sphere 2 can be changed, so that the temperature distribution of the sample stage 13 becomes more uniform.

[0053] By adjusting the height and tilt angle of the sample stage 13 in real time, the electromagnetic field distribution is improved, and further the coating thickness becomes more uniform, and the coating quality is improved.

[0054] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for improving coating quality, characterized in that: A microwave plasma chemical vapor deposition device is used, wherein the microwave plasma chemical vapor deposition device comprises a discharge chamber and a sample stage. The sample stage is arranged in the discharge cavity, and an inner cavity plate is also arranged in the discharge cavity, a through hole is arranged in the middle of the inner cavity plate, and the outer edge of the inner cavity plate is slidably matched with the inner wall of the cavity; The intracavity plate is located below the sample stage, a lifting rod is provided at the bottom of the sample stage, and the lifting rod passes through the through hole of the intracavity plate; The method comprises the following steps: Real-time detection of the temperature at the center and four directions of the edge of the sample stage; When the temperature at the center of the sample stage is higher than the average temperature at the edge of the sample stage, the sample stage is raised by a preset distance. After continuing to monitor for a preset time, when the temperature at the center of the sample stage is still higher than the average temperature at the edge of the sample stage, the height of the cavity plate is lowered. The temperatures of two opposite positions on the edge of the sample stage are the first temperature and the second temperature respectively. When the difference between the first temperature and the second temperature is greater than a preset difference, the inclination angle of the sample stage is adjusted so that the position corresponding to the lower temperature of the first temperature and the second temperature of the sample stage moves a preset distance in the direction away from the plasma ball.

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