Method for controlling pressure in deposition cavity and chemical vapor deposition method

Abstract

The invention discloses a control method for pressure in a deposition cavity and a chemical vapor deposition method, belongs to the technical field of chemical vapor deposition, and aims to solve the problem of poor pressure regulation capability when the pressure in the deposition cavity is abnormal in the prior art. According to the method, if cavity pressure data is lower than a cavity pressure threshold value range, the opening degree of a first flow regulating valve arranged on a connecting pipeline of a deposition cavity and a vacuum pump is reduced; if the cavity pressure data is higher than the cavity pressure threshold value range, the opening degree of the first flow regulating valve is increased; if the branch pipe pressure data is lower than the branch pipe pressure threshold value range, the opening degree of a second flow regulating valve arranged on the exhaust branch pipeline is reduced; if the branch pipe pressure data is higher than the branch pipe pressure threshold value range, the opening degree of the second flow regulating valve is increased; if the main pipe air pressure data is lower than the main pipe air pressure threshold range, the rotating speed of the air suction pump is reduced; if the main pipe air pressure data is higher than the main pipe air pressure threshold range, the rotating speed of the suction pump is increased. The method can be used for chemical vapor deposition.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical vapor deposition, and in particular relates to a method for controlling pressure in a deposition chamber and a chemical vapor deposition method. Background Art

[0002] Diamonds are usually grown using chemical vapor deposition technology. During the deposition process, the pressure in the deposition chamber needs to be strictly regulated and controlled. Pressure changes or fluctuations in the deposition chamber will affect the growth rate, purity and color of the diamond.

[0003] Currently, usually only the pressure in the deposition chamber is detected. However, when the pressure in the deposition chamber is abnormal, the exhaust capacity of the exhaust unit will also affect the regulation of the pressure in the deposition chamber. Summary of the invention

[0004] In view of the above analysis, the present invention aims to provide a method for controlling the pressure in a deposition chamber and a chemical vapor deposition method, so as to solve the problem of poor pressure regulation capability when the pressure in the deposition chamber is abnormal in the prior art.

[0005] The purpose of the present invention is mainly achieved through the following technical solutions.

[0006] The present invention provides a method for controlling the pressure in a deposition chamber, wherein an exhaust unit is used to exhaust the deposition chamber, the exhaust unit comprises a vacuum pump, an exhaust branch pipeline, an exhaust main pipeline and an air suction pump connected in sequence along the gas flow direction, the deposition chamber, the vacuum pump and the exhaust branch pipeline correspond one to one, and multiple exhaust branch pipelines correspond to one exhaust main pipeline and the air suction pump; the control method comprises the following steps:

[0007] Step 1: Control the inlet pressure of the deposition chamber to remain constant;

[0008] Step 2: Real-time detection of cavity pressure data in the deposition cavity, branch pipe pressure data in the exhaust branch pipe, and main pipe pressure data in the exhaust main pipe;

[0009] Step 3: Determine whether the cavity pressure data is within the cavity pressure threshold range. If the cavity pressure data is lower than the cavity pressure threshold range, the opening of the first flow regulating valve provided on the pipeline connecting the deposition chamber and the vacuum pump is reduced; if the cavity pressure data is higher than the cavity pressure threshold range, the opening of the first flow regulating valve is increased; if the cavity pressure data is within the cavity pressure threshold range, the opening of the first flow regulating valve remains unchanged;

[0010] Determine whether the branch pipe pressure data is within the branch pipe pressure threshold range. If the branch pipe pressure data is lower than the branch pipe pressure threshold range, the opening of the second flow regulating valve provided on the exhaust branch pipe is reduced; if the branch pipe pressure data is higher than the branch pipe pressure threshold range, the opening of the second flow regulating valve is increased; if the branch pipe pressure data is within the branch pipe pressure threshold range, the opening of the second flow regulating valve remains unchanged;

[0011] It is determined whether the main air pressure data is within the main air pressure threshold range. If the main air pressure data is lower than the main air pressure threshold range, the suction pump speed is reduced; if the main air pressure data is higher than the main air pressure threshold range, the suction pump speed is increased; if the main air pressure data is within the main air pressure threshold range, the suction pump speed remains unchanged.

[0012] Furthermore, the cavity pressure threshold range, the branch pipe pressure threshold range and the main pipe pressure threshold range decrease in sequence.

[0013] Furthermore, the cavity pressure threshold range is 50-100 kPa.

[0014] Furthermore, the branch pipe pressure threshold range is -500 to -600Pa.

[0015] Furthermore, the main pipe air pressure threshold range is -700 to -800Pa.

[0016] The present invention also provides a chemical vapor deposition method, comprising the following steps:

[0017] Step A: providing a substrate and a vapor deposition device, wherein the vapor deposition device comprises a gas supply unit, a deposition chamber and an exhaust unit connected in sequence;

[0018] Step B: placing the substrate on a substrate holder in a deposition chamber;

[0019] Step C: turning on the induction heating coil to heat the deposition chamber;

[0020] Step D: Turn on the gas supply unit to introduce working gas into the deposition chamber, so that the working gas reacts and deposits a diamond layer on the surface of the substrate;

[0021] In step D, during the reaction of the working gas, the pressure in the deposition chamber is controlled by using the method for controlling the pressure in the deposition chamber as claimed in any one of claims 1 to 5.

[0022] Furthermore, in step C, the temperature in the deposition chamber is 800-1000°C.

[0023] Furthermore, the distance between two adjacent deposition chambers is 1.5-3.0 m.

[0024] Furthermore, in step D, after the gas supply unit is turned on and before the working gas is introduced into the deposition chamber 1, the following steps are also included:

[0025] Preheat the working gas flowing out of the gas supply unit.

[0026] Furthermore, the preheating temperature is 700-780°C.

[0027] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0028] A) The method for controlling the pressure in the deposition chamber provided by the present invention simultaneously detects the cavity pressure data in the deposition chamber, the branch pipe pressure data in the exhaust branch pipe and the main air pressure data in the exhaust main pipe, and determines whether the above air pressure data are within the corresponding threshold range. If any of the pressure data is not within the corresponding threshold range, the pressure data can be adjusted in time by using the corresponding adjustment method, so as to ensure that the deposition chamber and the subsequent exhaust branch pipe and exhaust main pipe are within the threshold range, so that when the pressure abnormality occurs in the deposition chamber, the exhaust branch pipe and the exhaust main pipe have sufficient exhaust patency, which is convenient for adjusting the air pressure in the deposition chamber.

[0029] B) The method for controlling the pressure in the deposition chamber provided by the present invention can adjust the pressure in the deposition chamber by adjusting the opening of the first flow regulating valve to ensure the pressure stability in the deposition chamber; can adjust the pressure in the exhaust branch pipeline by adjusting the opening of the second flow regulating valve to ensure the pressure stability in the exhaust branch pipeline; through the main pipe pressure acquisition unit and the fan control unit, the air pressure in the exhaust main pipeline can be monitored in real time, and the rotation speed of the suction pump can be adjusted in real time according to the air pressure, which can not only ensure the smooth discharge of the gas in the exhaust main pipeline, but also ensure the stability of the air pressure in the exhaust main pipeline.

[0030] C) The method for controlling the pressure in the deposition chamber provided by the present invention is to set a suction pump specially used for exhaust at the rear end of the vacuum pump. The vacuum pump can promote the gas in the deposition chamber to flow out of the deposition chamber, and facilitate the gas to be discharged to the outside in time from the connecting pipeline between the vacuum pump and the suction pump, thereby improving the smoothness of exhaust.

[0031] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the embodiments of the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0033] Figure 1 A control flow chart of the chamber pressure in the method for controlling the pressure in the deposition chamber provided in the first embodiment of the present invention is provided;

[0034] Figure 2 A control flow chart of the branch pipe pressure in the method for controlling the pressure in the deposition chamber provided in Example 1 of the present invention is provided;

[0035] Figure 3 A control flow chart of the main pipe pressure in the method for controlling the pressure in the deposition chamber provided in the first embodiment of the present invention is provided;

[0036] Figure 4 A flow chart of the chemical vapor deposition method provided in Example 2 of the present invention is provided;

[0037] Figure 5 A schematic structural diagram of a vapor deposition device in a chemical vapor deposition method provided in Embodiment 2 of the present invention is provided;

[0038] Figure 6a A schematic diagram of the structure of a temperature regulating pipeline in a chemical vapor deposition method provided in Embodiment 2 of the present invention is provided, wherein the thermal expansion protrusion is not in contact with the contact sensor;

[0039] Figure 6b A schematic diagram of the structure of a temperature regulating pipeline in a chemical vapor deposition method provided in Embodiment 2 of the present invention is provided, wherein the thermal expansion protrusion contacts the contact sensor;

[0040] Figure 7 A schematic structural diagram of a deposition chamber and a preheating pipeline in a chemical vapor deposition method provided in Example 2 of the present invention is provided.

[0041] Reference numerals:

[0042] 1-deposition chamber; 101-heating inner shell; 102-insulation layer; 103-induction heating coil; 104-substrate rack; 2-temperature control pipeline; 201-contact sensor; 202-working air flow pipe; 203-temperature control outer tube; 204-thermal expansion protrusion; 3-suction pump; 4-vacuum pump; 5-main pipe pressure acquisition unit; 6-blower control unit; 7-cavity pressure acquisition unit; 8-first flow regulating valve; 9-first flow control unit; 10-branch pipe pressure acquisition unit; 11-second flow regulating valve; 12-second flow control unit; 13-exhaust main pipeline; 14-exhaust branch pipeline; 15-gas supply unit; 16-preheating chamber; 17-substrate; 18-first preheating section; 19-spherical preheating section; 20-second preheating section; 21-insulation layer. DETAILED DESCRIPTION

[0043] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0044] Embodiment 1

[0045] This embodiment provides a method for controlling the pressure in a deposition chamber, wherein an exhaust unit is used to exhaust the deposition chamber, the exhaust unit comprising a vacuum pump 4, an exhaust branch pipeline 14, an exhaust main pipeline 13 and an air suction pump 3 connected in sequence along the gas flow direction, the deposition chamber 1, the vacuum pump 4 and the exhaust branch pipeline 14 correspond one to one, and multiple exhaust branch pipelines 14 correspond to one exhaust main pipeline 13 and the air suction pump 3. The control method comprises the following steps:

[0046] Step 1: Control the inlet pressure of the deposition chamber 1 to remain constant;

[0047] Step 2: The cavity pressure acquisition unit 7 detects the cavity pressure data in the deposition cavity 1 in real time and transmits it to the first flow control unit 9;

[0048] The branch pipe pressure acquisition unit 10 detects the branch pipe pressure data in the exhaust branch pipe 14 in real time and transmits it to the second flow control unit 12;

[0049] The main pipe pressure acquisition unit 5 detects the main pipe air pressure data in the exhaust main pipe 13 in real time and transmits it to the fan control unit 6;

[0050] Step 3: The first flow control unit 9 receives the cavity pressure data and determines whether the cavity pressure data is within the cavity pressure threshold range. If the cavity pressure data is lower than the cavity pressure threshold range, the first flow control unit 9 controls the opening of the first flow regulating valve 8 to decrease; if the cavity pressure data is higher than the cavity pressure threshold range, the first flow control unit 9 controls the opening of the first flow regulating valve 8 to increase; if the cavity pressure data is within the cavity pressure threshold range, the first flow control unit 9 controls the opening of the first flow regulating valve 8 to remain unchanged, see Figure 1 ;

[0051] The second flow control unit 12 receives the branch pressure data and determines whether the branch pressure data is within the branch pressure threshold range. If the branch pressure data is lower than the branch pressure threshold range, the second flow control unit 12 controls the opening of the second flow regulating valve 11 to decrease; if the branch pressure data is higher than the branch pressure threshold range, the second flow control unit 12 controls the opening of the second flow regulating valve 11 to increase; if the branch pressure data is within the branch pressure threshold range, the second flow control unit 12 controls the opening of the second flow regulating valve 11 to remain unchanged, see Figure 2 ;

[0052] The exhaust control unit receives the main air pressure data and determines whether the main air pressure data is within the main air pressure threshold range. If the main air pressure data is lower than the main air pressure threshold range, it means that the air pressure in the deposition chamber 1 has decreased, and the fan control unit 6 controls the speed of the suction pump 3 to decrease; if the main air pressure data is higher than the main air pressure threshold range, it means that the air pressure in the deposition chamber 1 has decreased, and the fan control unit 6 controls the speed of the suction pump 3 to increase; if the main air pressure data is within the main air pressure threshold range, it means that the air pressure in the deposition chamber 1 is relatively stable, and the fan control unit 6 controls the speed of the suction pump 3 to remain unchanged, see Figure 3 .

[0053] Compared with the prior art, the method for controlling the pressure in the deposition chamber provided in the present embodiment simultaneously detects the chamber pressure data in the deposition chamber 1, the branch pipe pressure data in the exhaust branch pipe 14 and the main air pressure data in the exhaust main pipe 13, and determines whether the above-mentioned air pressure data are within the corresponding threshold range. If any of the pressure data is not within the corresponding threshold range, the pressure data can be adjusted in time by using the corresponding adjustment method, so as to ensure that the deposition chamber 1 and the subsequent exhaust branch pipe 14 and exhaust main pipe 13 are all within the threshold range, so that when the pressure abnormality occurs in the deposition chamber 1, the exhaust branch pipe 14 and the exhaust main pipe 13 have sufficient exhaust patency, which is convenient for adjusting the air pressure in the deposition chamber 1.

[0054] Specifically, by adjusting the opening of the first flow regulating valve 8, the pressure in the deposition chamber 1 can be adjusted to ensure the pressure stability in the deposition chamber 1; by adjusting the opening of the second flow regulating valve 11, the pressure in the exhaust branch pipeline 14 can be adjusted to ensure the pressure stability in the exhaust branch pipeline 14; through the main pressure acquisition unit 5 and the fan control unit 6, the air pressure in the exhaust main pipeline 13 can be monitored in real time, and the rotation speed of the suction pump 3 can be adjusted in real time according to the air pressure, which can not only ensure the smooth discharge of the gas in the exhaust main pipeline 13, but also ensure the stability of the air pressure in the exhaust main pipeline 13.

[0055] In addition, when adopting the exhaust unit of the above structure, a suction pump 3 specially used for exhaust is set at the rear end of the vacuum pump 4. The vacuum pump 4 can promote the gas in the deposition chamber 1 to flow out of the deposition chamber 1, so that the gas is discharged to the outside in time from the connecting pipeline between the vacuum pump 4 and the suction pump 3, thereby improving the smoothness of exhaust.

[0056] From the perspective of pressure control, the cavity pressure threshold range, the branch pipe pressure threshold range and the main pipe pressure threshold range decrease in sequence.

[0057] Exemplarily, the cavity pressure threshold range is 50 to 100 kPa, the branch pipe pressure threshold range is -500 to -600 Pa, and the main pipe pressure threshold range is -700 to -800 Pa.

[0058] It can be understood that for the adjustment of cavity pressure data, the above-mentioned exhaust unit also includes a cavity pressure acquisition unit 7, a first flow regulating valve 8 and a first flow control unit 9. The cavity pressure acquisition unit 7 is arranged in the deposition chamber 1, and the first flow regulating valve 8 is arranged on the connecting pipeline between the deposition chamber 1 and the vacuum pump 4. The first flow control unit 9 is respectively connected to the cavity pressure acquisition unit 7 and the first flow regulating valve 8.

[0059] Correspondingly, for the adjustment of branch pipe pressure data, the above-mentioned exhaust unit also includes a branch pipe pressure acquisition unit 10, a second flow regulating valve 11 and a second flow control unit 12. The branch pipe pressure acquisition unit 10 is arranged in the exhaust branch pipe 14, and the second flow regulating valve 11 is arranged on the exhaust branch pipe 14. Along the gas flow direction, the branch pipe pressure acquisition unit 10 is located in front of the second flow regulating valve 11, and the second flow control unit 12 is respectively connected to the branch pipe pressure acquisition unit 10 and the second flow regulating valve 11.

[0060] For the main pipe air pressure data, the exhaust unit further includes a main pipe pressure acquisition unit 5 and a fan control unit 6 . The fan control unit 6 is connected to the main pipe pressure acquisition unit 5 and the suction pump 3 , respectively. The main pipe pressure acquisition unit 5 is arranged in the exhaust main line 13 .

[0061] Embodiment 2

[0062] This embodiment provides a chemical vapor deposition method, see Figures 4 to 5 , including the following steps:

[0063] Step A: providing a substrate 17 and a vapor deposition device, the vapor deposition device comprising a gas supply unit 15, a deposition chamber 1 and an exhaust unit connected in sequence;

[0064] Step B: placing the substrate 17 on the substrate rack 104 in the deposition chamber 1;

[0065] Step C: turning on the induction heating coil 103 to heat the deposition chamber 1 so that the temperature in the deposition chamber 1 reaches 800-1000° C.;

[0066] Step D: Turn on the gas supply unit to introduce working gas (e.g., methane) into the deposition chamber 1, and the working gas reacts to deposit a diamond layer on the surface of the substrate 17;

[0067] It should be noted that in the above step D, during the reaction of the working gas, the pressure in the deposition chamber 1 is controlled by the method for controlling the pressure in the deposition chamber provided in the first embodiment.

[0068] Compared with the prior art, the beneficial effects of the chemical vapor deposition method provided in this embodiment are substantially the same as the beneficial effects of the method for controlling the pressure in the deposition chamber provided in the first embodiment, and are not described in detail here.

[0069] In order to ensure the rationality of the layout, the distance between two adjacent deposition chambers 1 is 1.5-3.0 m.

[0070] During the process of vapor deposition, it is necessary to continuously supply working gas into the deposition chamber 1. However, since the storage temperature of the working gas is relatively low, directly supplying the working gas will cause the temperature in the deposition chamber 1 to drop suddenly, which is not conducive to maintaining the temperature stability and pressure stability in the deposition chamber 1. Therefore, in the above step D, after the gas supply unit is turned on and before the working gas is introduced into the deposition chamber 1, the following steps are also included:

[0071] The working gas flowing out of the gas supply unit is preheated so that the temperature of the working gas supplied into the deposition chamber 1 reaches 700-780°C.

[0072] Specifically, the working gas can be preheated in the following two ways.

[0073] In one embodiment, the vapor deposition apparatus further comprises a preheating chamber 16, and the gas supply unit 15 is connected to the deposition chamber 1 via the preheating chamber 16. Exemplarily, the temperature of the deposition chamber 1 is 800-1000°C, and the temperature of the preheating chamber 16 is 700-780°C.

[0074] It is understandable that, in order to achieve the connection between the preheating chamber 16 and the deposition chamber 1 , the above-mentioned vapor deposition equipment further includes a temperature regulating pipeline 2 , and the preheating chamber 16 is connected to the deposition chamber 1 through the temperature regulating pipeline 2 .

[0075] Taking into account that the temperature of the preheating chamber 16 is very close to the deposition chamber 1, the working temperature may be too high at the position of the temperature control pipeline 2 close to the deposition chamber 1, and the working gas with too high a temperature may react and deposit in the temperature control pipeline 2. In order to avoid the above situation, the structure of the temperature control pipeline 2, specifically, includes a working air flow pipe 202 and a temperature control outer tube 203 arranged outside the working air flow pipe 202, there is a gap between the working air flow pipe 202 and the temperature control outer tube 203, the outer wall of the working air flow pipe 202 is provided with a thermal expansion protrusion 204, the thermal expansion protrusion 204 has a large thermal expansion coefficient, the inner wall of the temperature control outer tube 203 is provided with a contact sensor 201, the thermal expansion protrusion 204 corresponds to the position of the contact sensor 201, and there is a small gap between the top of the thermal expansion protrusion 204 and the contact sensor 201.

[0076] In this way, when the working air temperature in the temperature regulating pipeline 22 does not exceed the temperature threshold (for example, 800° C.), there is a small gap between the top of the thermal expansion protrusion 204 and the contact sensor 201, and the working air flow pipe 202 and the temperature regulating outer pipe 203 are isolated from each other by air. The gap between the working air flow pipe 202 and the temperature regulating outer pipe 203 can form air insulation, see Figure 6a .

[0077] When the working gas temperature in the temperature regulating pipeline 22 exceeds the temperature threshold (for example, 800° C.), the heat in the working gas is transferred to the thermal expansion protrusion 204, so that the thickness of the thermal expansion protrusion 204 increases, and the outer ring surface of the thermal expansion protrusion 204 contacts the contact sensor 201, see Figure 6b The thermal expansion protrusions 204 and the contact sensor 201 that are in contact with each other form a heat-conducting column as a heat-conducting structure, so that the working air flow pipe 202 can exchange heat with the external environment. The heat of the working gas is transferred to the external environment through the working air flow pipe 202, the thermal expansion protrusions 204, the contact sensor 201 and the temperature-adjusting outer tube 203 in turn.

[0078] It should be noted that, through the specially structured temperature regulating pipeline 2, it is possible to realize automatic adjustment of the working gas temperature in the working gas flow pipe 202 without setting up a temperature collection unit and without destroying the overall structure and air tightness of the working gas flow pipe 202, thereby avoiding the situation where the working gas temperature is too high at the position where the temperature regulating pipeline 2 is close to the deposition chamber 1.

[0079] In another embodiment, the deposition chamber 1 includes a heating inner shell 101, a temperature insulating layer 102, an induction heating coil 103 and a substrate rack 104, see Figure 7 The temperature insulation layer 102 is sleeved on the outer wall of the heating inner shell 101, the induction heating coil 103 is arranged between the temperature insulation layer 102 and the heating inner shell 101 and is in direct contact with the heating inner shell 101, the substrate rack 104 is arranged in the heating inner shell 101, and the substrate 17 is placed on the substrate rack 104. The deposition chamber 1 with such a structure can realize uniform heating of the substrate 17.

[0080] In order to preheat the working gas, the gas supply unit 15 is connected to the inner cavity of the deposition chamber 1 through a preheating pipeline. The structure of the preheating pipeline includes a heat transfer inner tube and a thermal insulation layer 21 sleeved on the outer wall of the heat transfer inner tube. The heat transfer inner tube and the heating inner shell 101 are made of the same material, and one end of the heat transfer inner tube is in direct contact with the heating inner shell 101. The heat generated by the induction heating coil 103 is transferred to the heating inner shell 101, and the substrate 17 is radiantly heated by the heating inner shell 101. The heat is transferred along the heating inner shell 101 to the heat transfer inner tube, thereby preheating the working gas flowing in the heat transfer inner tube.

[0081] In addition, it should be noted that, in practical applications, since the heat transfer inner tube is at a certain distance from the induction heating coil 103, the working gas flowing in the heat transfer inner tube is usually not heated to 800-1000°C.

[0082] In order to fully preheat the working gas, the above-mentioned heat transfer inner tube includes a first preheating section 18, a spherical preheating section 19 and a second preheating section 20 which are connected in sequence from the gas supply unit 15 to the deposition chamber 1. The gas outlet direction of the first preheating section 18 is tangent to the spherical preheating section 19, so that the working gas flowing out of the first preheating section 18 is supplied into the spherical preheating section 19 along the tangent direction of the spherical preheating section 19 and swirls in the spherical preheating section 19, thereby extending the residence time of the working gas in the heat transfer inner tube and ensuring sufficient preheating of the working gas.

[0083] In order to further improve the preheating effect of the working gas, the diameter of the spherical preheating section 19 is larger than the diameter of the first preheating section 18. The flow rate of the working gas flowing from the first preheating section 18 into the spherical preheating section 19 will be appropriately reduced, further extending the residence time of the working gas in the spherical preheating section 19.

[0084] In order to ensure the working gas flow rate supplied into the deposition chamber 1, the diameter of the spherical preheating section 19 is larger than the diameter of the second preheating section 20. In this way, the flow rate of the working gas flowing from the spherical preheating section 19 into the second preheating section 20 will be appropriately increased so that more working gas can flow onto the substrate 17.

[0085] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for controlling the pressure in a deposition chamber, characterized in that: An exhaust unit is used to exhaust the deposition chamber, and the exhaust unit includes a vacuum pump, an exhaust branch pipeline, an exhaust main pipeline and an air suction pump connected in sequence along the gas flow direction. The deposition chamber, the vacuum pump and the exhaust branch pipeline correspond to each other one by one, and multiple exhaust branch pipelines correspond to one exhaust main pipeline and an air suction pump; The control method comprises the following steps: Step 1: Control the inlet pressure of the deposition chamber to remain constant; Step 2: Real-time detection of cavity pressure data in the deposition cavity, branch pipe pressure data in the exhaust branch pipe, and main pipe pressure data in the exhaust main pipe; Step 3: Determine whether the cavity pressure data is within the cavity pressure threshold range. If the cavity pressure data is lower than the cavity pressure threshold range, the opening of the first flow regulating valve provided on the pipeline connecting the deposition chamber and the vacuum pump is reduced; if the cavity pressure data is higher than the cavity pressure threshold range, the opening of the first flow regulating valve is increased; if the cavity pressure data is within the cavity pressure threshold range, the opening of the first flow regulating valve remains unchanged; Determine whether the branch pipe pressure data is within the branch pipe pressure threshold range. If the branch pipe pressure data is lower than the branch pipe pressure threshold range, the opening of the second flow regulating valve provided on the exhaust branch pipe is reduced; if the branch pipe pressure data is higher than the branch pipe pressure threshold range, the opening of the second flow regulating valve is increased; if the branch pipe pressure data is within the branch pipe pressure threshold range, the opening of the second flow regulating valve remains unchanged; It is determined whether the main air pressure data is within the main air pressure threshold range. If the main air pressure data is lower than the main air pressure threshold range, the suction pump speed is reduced; if the main air pressure data is higher than the main air pressure threshold range, the suction pump speed is increased; if the main air pressure data is within the main air pressure threshold range, the suction pump speed remains unchanged.

2. The method for controlling the pressure in a deposition chamber according to claim 1, characterized in that: The cavity pressure threshold range, the branch pipe pressure threshold range and the main pipe pressure threshold range decrease in sequence.

3. The method for controlling the pressure in a deposition chamber according to claim 2, characterized in that: The cavity pressure threshold range is 50-100 kPa.

4. The method for controlling the pressure in a deposition chamber according to claim 2, characterized in that: The branch pipe pressure threshold range is -500 to -600 Pa.

5. The method for controlling the pressure in a deposition chamber according to claim 2, characterized in that: The main pipe air pressure threshold range is -700 to -800 Pa.

6. A chemical vapor deposition method, characterized in that: The steps include: Step A: providing a substrate and a vapor deposition device, wherein the vapor deposition device comprises a gas supply unit, a deposition chamber and an exhaust unit connected in sequence; Step B: placing the substrate on a substrate holder in a deposition chamber; Step C: turning on the induction heating coil to heat the deposition chamber; Step D: Turn on the gas supply unit to introduce working gas into the deposition chamber, and the working gas reacts to deposit a diamond layer on the surface of the substrate; In the step D, during the reaction of the working gas, the pressure in the deposition chamber is controlled by the method for controlling the pressure in the deposition chamber as described in any one of claims 1 to 5.

7. The chemical vapor deposition method according to claim 6, characterized in that: In the step C, the temperature in the deposition chamber is 800-1000°C.

8. The chemical vapor deposition method according to claim 6, characterized in that: The distance between two adjacent deposition chambers 1 is 1.5-3.0 m.

9. The chemical vapor deposition method according to claim 6, characterized in that: In the step D, after the gas supply unit is turned on and before the working gas is introduced into the deposition chamber, the following steps are also included: Preheat the working gas flowing out of the gas supply unit.

10. The chemical vapor deposition method according to claim 9, characterized in that: The preheating temperature is 700-780°C.

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