Silicon carbide coating graphite disc with multiple types of surface roughness and preparation method thereof

Abstract

The invention belongs to the technical field of semiconductors, and particularly relates to a multi-type surface roughness silicon carbide coating graphite disc and a preparation method thereof. The core of the preparation method is as follows: reverse design is carried out based on a preset surface roughness change rule, that is, the target roughness of each area of the graphite disc is determined firstly, and then according to the rule, the roughness of the area with the initial roughness lower than a preset threshold value is increased by a variable quantity after deposition, and after the area higher than the threshold value is deposited, reducing the roughness by a variable quantity, reversely calculating the initial roughness required by the semi-finished product of the graphite disc, and then carrying out machining, surface pretreatment and chemical vapor deposition to form the silicon carbide coating with multiple types of target roughness at one time. The method fundamentally avoids post-processing of the silicon carbide coating, solves the technical problems of low yield (less than 80%) and complex process of the traditional process, increases the yield to 95% or above, and is simple in process, low in cost and suitable for mass production.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, specifically relating to a silicon carbide coated graphite disk with multiple surface roughnesses and its preparation method. Background Technology

[0002] Silicon carbide-coated graphite disks are critical components used to support and transport wafers in semiconductor manufacturing. The surface roughness requirements of the graphite disks vary across different process stages: some areas require lower roughness to ensure stable support and low contamination, while others require higher roughness to enhance adhesion or facilitate gas flow. Therefore, achieving controllable fabrication of multiple types of roughness on the surface of a single graphite disk has become a key technological requirement in this field.

[0003] In semiconductor manufacturing, silicon carbide-coated graphite disks require varying surface roughness in different areas to meet diverse process requirements. The current mainstream approach is "CVD deposition of silicon carbide coating followed by machining," where a uniform silicon carbide coating is first formed on the graphite substrate, then specific areas are machined to adjust the roughness, and finally contaminants are removed by acid etching. However, this approach suffers from low yield (typically <80%) because the silicon carbide coating is hard and brittle, making machining prone to cracking or peeling. Furthermore, the acid etching process increases process complexity and cost.

[0004] While the industry recognizes that machining the graphite substrate before depositing a silicon carbide coating can avoid post-processing of the hard and brittle coating, this approach has long been unrealized. The core obstacle lies in the fact that the chemical vapor deposition (CVD) process itself alters the substrate surface morphology, and this process involves complex surface reactions and film growth mechanisms. This results in a lack of a definite and predictable correlation between the initial roughness obtained from machining the graphite substrate and the final roughness of the deposited silicon carbide coating. Because the evolution of surface morphology caused by the deposition process cannot be accurately predicted, it is impossible to reliably obtain differentiated target roughness on the final product by precisely designing the initial roughness of the graphite substrate. This lack of a "deposition-morphology" control link has kept the "machining first, deposition later" approach theoretically inaccessible, unable to replace traditional methods with inherent flaws. Therefore, there is an urgent need to develop a technical solution for predictable and controllable roughness differentiation in silicon carbide coatings. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a method for preparing graphite disks with various surface roughness silicon carbide coatings that has a high yield and a simple process.

[0006] Another object of the present invention is to provide a silicon carbide coated graphite disk with multiple types of surface roughness prepared by the above method or directly defined by structural features.

[0007] The technical solution of the present invention is as follows: Firstly, a method for preparing silicon carbide coated graphite disks with multiple surface roughnesses is provided, comprising the following steps: (1) Determine the target surface roughness of each region on the graphite disk surface; (2) Based on the surface roughness variation law, the initial surface roughness of the graphite disk semi-finished product applied to machining is determined by the target surface roughness of each region in reverse; wherein, the surface roughness variation law is as follows: in the subsequent chemical vapor deposition of silicon carbide coating, the surface roughness of the first region with an initial surface roughness lower than a preset threshold will increase by a first change amount after deposition, while the surface roughness of the second region with an initial surface roughness higher than the preset threshold will decrease by a second change amount after deposition; (3) Based on the determined initial surface roughness, the corresponding areas of the graphite disk semi-finished product are machined and surface pretreated; (4) Chemical vapor deposition is performed on the pre-treated graphite disk semi-finished product to form a silicon carbide coating on its surface, thereby directly obtaining a silicon carbide coated graphite disk with multiple types of target surface roughness.

[0008] Preferably, the preset threshold in step (2) is between 1.5 μm and 2 μm.

[0009] Preferably, in step (2), the absolute values ​​of the first change and the second change are both in the range of 0.2 μm to 0.4 μm.

[0010] Preferably, in step (2), the absolute values ​​of the first change and the second change are both 0.3 μm.

[0011] Preferably, in step (3), the spindle speed used for machining the first region is higher than the spindle speed used for machining the second region; and the feed rate used for machining the first region is lower than the feed rate used for machining the second region.

[0012] Preferably, in step (3), the spindle speed of the first region is 10000~15000 r / min, and the feed rate is 2000~3000 mm / min; the spindle speed of the second region is 5000~9500 r / min, and the feed rate is 3000~4000 mm / min; the feed amount in the vertical direction of both the first region and the second region is 0.2~0.25 mm.

[0013] Preferably, the chemical vapor deposition in step (4) is carried out under a protective atmosphere, with a reaction gas source system of CH3SiCl3(MTS)-Ar-H2 introduced, the deposition temperature is 1200~1400℃, and the deposition time is 1.5~5h. H2 is the carrier gas of MTS, Ar is the dilution gas, the flow ratio of H2 to Ar is (5~20):1, the flow rate of Ar is 10~40L / min, and the flow rate of MTS is 10~80L / min.

[0014] In a second aspect, a multi-type surface roughness silicon carbide coated graphite disk is provided, which is prepared by any one of the preparation methods described in the first aspect.

[0015] Thirdly, a silicon carbide coated graphite disk with multiple types of surface roughness is provided. The surface of the silicon carbide coated graphite disk includes at least one first region with a roughness of 0.8~1.8μm and at least one second region with a roughness of 1.7~4.7μm, and the silicon carbide coating is an integrally formed structure without post-processing.

[0016] Compared with the prior art, the advantages of the present invention are: (1) It fundamentally solves the industry problem of low yield: Existing technologies are prone to micro-cracks or peeling of the coating due to machining on the hard and brittle silicon carbide coating, and the yield is usually less than 80%. The present invention completely avoids any mechanical processing of the deposited coating by using the process sequence of "machining the graphite disk first and then depositing the coating", thereby eliminating the risk of damage to the coating due to post-processing from the root and steadily increasing the yield to more than 95%.

[0017] (2) It achieves precise and predictable control of surface roughness of various types, and overcomes the core technical obstacle of the "processing first, deposition later" path: The fundamental reason why the existing technology cannot apply the "processing first, deposition later" path is that the influence of the deposition process on the surface morphology is unpredictable. This invention quantitatively defines the variation law of surface roughness during chemical vapor deposition (i.e., it approaches the threshold and has a quantifiable variation of about ±0.3μm), and based on this law, it creates a "reverse design" method. By using the target surface roughness of the silicon carbide coating, the initial surface roughness of the graphite disk is calculated in reverse, realizing the qualitative change from "uncontrollable" to "precisely controllable".

[0018] (3) The process flow is significantly simplified, and production costs and environmental pressure are reduced: Existing technologies require complex acid pickling post-treatment processes to remove pollutants introduced by machining. Since the post-processing of the coating is eliminated, the necessary subsequent acid pickling step is also eliminated. This not only shortens the production cycle and reduces chemical consumption and equipment costs, but also completely avoids the environmental burden caused by waste acid treatment, making the process greener and more economical.

[0019] (4) Improved intrinsic quality and long-term reliability of the final product: Products prepared by traditional methods have coatings with potential microcracks caused by machining, which are prone to propagation and failure under harsh conditions such as thermal shock. The silicon carbide coating prepared by this invention is a complete, mechanically undamaged, integrally molded structure with higher density and integrity. Therefore, the product has superior thermal shock resistance, longer service life, and higher operational reliability, fundamentally improving the intrinsic quality of the product. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a flowchart illustrating the overall process flow of the preparation method of the present invention; Figure 2 This is a schematic diagram showing the functional area division of the graphite disk in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the functional area division of the graphite disk in Embodiment 2 of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to specific embodiments: The core of this invention lies in discovering and defining the surface roughness variation law, namely, that the CVD deposition process causes the surface roughness to approach an intermediate threshold. Based on this law, a "reverse design" machining strategy is proposed: when setting the initial roughness for the graphite disk semi-finished product, for the first region where the target roughness is lower than the threshold, its preset initial roughness is set to be lower than the target value by a first change amount (e.g., 0.3µm); for the second region where the target roughness is higher than the threshold, its preset initial roughness is set to be higher than the target value by a second change amount (e.g., 0.3µm). After the subsequent CVD deposition process, the surface roughness of each region will change exactly to the target value, thereby achieving precise control.

[0022] Example 1

[0023] Objective: such as Figure 2 As shown, a silicon carbide coated graphite disk is prepared, requiring region A (wafer placement area, corresponding to the first region) Ra=1.0µm, region B (transition region, corresponding to the second region) Ra=2.5µm, and region C (positioning region, corresponding to the second region) Ra=4.0µm.

[0024] Implementation process: The process flow is as follows Figure 1 As shown.

[0025] (1) Based on the rules, reverse design and differentiated machining: D10R0.5 diamond coated milling cutter is used, where D10 indicates that the milling cutter cutting diameter is 10mm and R0.5 indicates that the bottom tooth radius of the milling cutter is 0.5mm.

[0026] Based on the predetermined variation law of the present invention (the preset threshold is 1.8µm, and the variation amount is 0.3µm), reverse design is performed: Region A (target final Ra = 1.0µm < 1.8µm preset threshold): According to the pattern, the roughness will increase after deposition, therefore the initial roughness should be preset as: initial Ra = 1.0 - 0.3 = 0.7µm. The spindle speed is set to 14000 r / min, the feed rate to 2200 mm / min, and the Z-axis feed is 0.2 mm. The measured Ra after machining is approximately 0.7µm.

[0027] Region B (Target final Ra = 2.5µm > 1.8µm preset threshold): According to the pattern, the roughness will decrease after deposition, therefore the initial roughness should be preset as: Ra initial = 2.5 + 0.3 = 2.8µm. The spindle speed was set to 9000 r / min, the feed rate to 3000 mm / min, and the Z-axis feed to 0.2 mm. The measured Ra after machining was approximately 2.8µm.

[0028] Region C (Target final Ra = 4.0µm > 1.8µm preset threshold): According to the pattern, the roughness will decrease after deposition, therefore the initial roughness should be preset as: Ra initial = 4.0 + 0.3 = 4.3µm. The spindle speed was set to 5500 r / min, the feed rate to 3600 mm / min, and the Z-axis feed to 0.2 mm. The measured Ra after machining was approximately 4.3µm.

[0029] (2) Cleaning and drying: The semi-finished graphite disc after machining is blown with high pressure clean air, then ultrasonically cleaned with neutral cleaning agent, rinsed with deionized water, and finally dried at 120°C.

[0030] (3) CVD deposition of silicon carbide coating: The graphite disk semi-finished product was placed in a vacuum furnace, and after evacuation, the temperature was raised to 1250℃ at a rate of 6℃ / min under an Ar protective atmosphere. Then, an MTS-Ar-H2 reaction gas source system was introduced, in which the H2 to Ar flow ratio was 10:1, the Ar flow rate was 15L / min, and the MTS flow rate was 40L / min. The deposition was carried out at this temperature for 3 hours. After the deposition was completed, the furnace was cooled to below 40℃ and then removed.

[0031] Results: Measurements showed that the final surface roughness Ra was approximately 1.02 µm for region A, 2.48 µm for region B, and 3.98 µm for region C, all highly consistent with the design targets. To further verify the product's reliability, the sample underwent 10 thermal shock tests (rapid cooling from 1000℃ to 40℃). After the tests, no microcrack propagation or peeling was observed in the coating in any region, and the coating remained intact. The yield rate of this batch exceeded 95%.

[0032] Example 2

[0033] Objective: such as Figure 3 As shown, a silicon carbide coated graphite disk 2 is prepared, requiring region A (wafer placement area, corresponding to the first region) Ra=1.5μm, region B (transition area, corresponding to the second region) Ra=3.0μm, and region C (positioning area, corresponding to the second region) Ra=4.5μm.

[0034] Implementation process: The process flow is as follows Figure 1 As shown.

[0035] (1) Based on the rules, reverse design and differentiated machining: D10R0.5 diamond coated milling cutter is used, where D10 indicates that the milling cutter cutting diameter is 10mm and R0.5 indicates that the bottom tooth radius of the milling cutter is 0.5mm.

[0036] Based on the predetermined variation law of the present invention (the preset threshold is 1.8µm, and the variation amount is 0.3µm), reverse design is performed: Region A (target final Ra = 1.5µm < 1.8µm preset threshold): According to the pattern, the roughness will increase after deposition, therefore the initial roughness should be preset as: initial Ra = 1.5 - 0.3 = 1.2µm. The spindle speed is set to 14000 r / min, the feed rate to 2500 mm / min, and the Z-axis feed to 0.2 mm for machining. The measured Ra after machining is approximately 1.2μm.

[0037] Region B (Target final Ra = 3.0µm > 1.8µm preset threshold): According to the pattern, the roughness will decrease after deposition, therefore the initial roughness should be preset as: Ra initial = 3.0 + 0.3 = 3.3µm. The spindle speed is set to 9000 r / min, the feed rate to 3200 mm / min, and the Z-axis feed to 0.2 mm for machining. The measured Ra after machining is approximately 3.3μm.

[0038] Region C (Target final Ra = 4.5µm > 1.8µm preset threshold): According to the pattern, the roughness will decrease after deposition, therefore the initial roughness should be preset as: Ra initial = 4.5 + 0.3 = 4.8µm. The spindle speed was set to 5500 r / min, the feed rate to 3800 mm / min, and the Z-axis feed to 0.2 mm for machining. The measured Ra after machining was approximately 4.8μm.

[0039] (2) Cleaning and drying: The semi-finished graphite disc after machining is blown with high pressure clean air, then ultrasonically cleaned with neutral cleaning agent, rinsed with deionized water, and finally dried at 120°C.

[0040] (3) CVD deposition of silicon carbide coating: The graphite disk semi-finished product was placed in a vacuum furnace, and after evacuation, the temperature was raised to 1350℃ at a rate of 8℃ / min under an Ar protective atmosphere. Then, an MTS-Ar-H2 reaction gas source system was introduced, in which the H2 to Ar flow ratio was 20:1, the Ar flow rate was 20L / min, and the MTS flow rate was 60L / min. The deposition was carried out at this temperature for 3 hours. After the deposition was completed, the furnace was cooled to below 40℃ and then removed.

[0041] Results: Measurements showed that the final surface roughness Ra was approximately 1.52 μm in region A, 2.98 μm in region B, and 4.49 μm in region C, all within the design tolerance range. To further verify the product's reliability, the sample underwent 10 thermal shock tests (rapid cooling from 1000℃ to 40℃). After the tests, no microcrack propagation or peeling was observed in the coating of any region, and the coating remained intact.

[0042] The above embodiments demonstrate that the "surface roughness variation law" and "reverse design" methods defined and utilized in this invention remain stable and effective under different target roughness and CVD process parameters, further verifying the universality and repeatability of this invention.

[0043] Comparative Example 1 Objective: To fabricate a silicon carbide-coated graphite disk with Ra = 1.0 μm in region A (wafer placement area), Ra = 2.5 μm in region B (transition region), and Ra = 4.0 μm in region C (positioning region). The objective is exactly the same as in Example 1 for comparison.

[0044] Implementation process: (1) First, CVD deposition of silicon carbide coating was performed: A graphite disk of the same specification was taken and directly placed into a vacuum furnace for silicon carbide coating deposition. The process parameters were exactly the same as those in step (3) of Example 1: the temperature was raised to 1250℃ at 6℃ / min under Ar protective atmosphere, and the MTS-Ar-H2 reaction gas source system (H2 / Ar=10:1, Ar=15L / min, MTS=40L / min) was introduced and the deposition was carried out for 3 hours. After deposition, a silicon carbide coated graphite disk with uniform surface roughness was obtained, and its initial surface roughness Ra was about 0.8μm.

[0045] (2) Then perform differentiated machining: using the same model (D10R0.5) diamond-coated end mill as in Example 1, machine the areas B and C that need to achieve the target roughness.

[0046] Area B (target Ra=2.5μm): Set the spindle speed to 9000r / min, feed rate to 3000mm / min, and Z-axis feed to 0.2mm for milling "roughening".

[0047] Region C (target Ra=4.0μm): Set spindle speed to 5500r / min, feed rate to 3600mm / min, Z-axis feed to 0.2mm, and perform milling and roughening.

[0048] Region A (target Ra=1.0μm): Remain in its original state after deposition, without any machining.

[0049] Pickling treatment: The machined graphite disk is pickled to remove any metal contamination that may have been introduced into the cutting tool during machining. Specifically, it is soaked in a 20% nitric acid solution for 30 minutes, then rinsed thoroughly with deionized water, and finally dried.

[0050] Results and Detection: Coating integrity: The samples, especially the machined areas B and C, were observed using a metallographic microscope. Obvious microcracks were found at the edges and along the tool path in these areas, with some areas even showing slight coating peeling.

[0051] Surface roughness: Measurements show that the final surface roughness Ra≈0.8μm for region A, Ra≈2.6μm for region B, and Ra≈4.1μm for region C. The surface roughness basically meets the design requirements.

[0052] Reliability testing: The sample was subjected to 10 thermal shock tests (rapid cooling from 1000℃ to 40℃). After the tests, the microcracks in regions B and C expanded significantly, and the area of ​​spalling increased.

[0053] Yield statistics: Of the 50 pieces produced using this method, 12 were scrapped due to severe coating cracking after machining or failure to pass the thermal shock test, resulting in a yield rate of 76%.

[0054] Conclusion: Comparative Example 1 confirms that although the traditional "coating first, processing later" process can adjust the surface roughness, it will cause irreversible mechanical damage to the high-hardness silicon carbide coating, resulting in microcracks and potential coating failure risks, low yield, and poor product reliability.

[0055] Comparative Example 2 Objective: To prepare graphite disks with final surface roughness Ra=1.0μm in region A, Ra=2.5μm in region B, and Ra=4.0μm in region C. This comparative example aims to compare whether the roughness variation law discovered in this invention can be accurately controlled even if the "process first, coat later" approach is adopted.

[0056] Implementation process: Differentiated machining (irregular prediction and reverse design): Machining of graphite disk semi-finished products. The operator did not use the "±0.3μm" rule discovered in this invention for reverse design, but directly used the final target value as the machining target of the graphite matrix.

[0057] Region A: The target is directly set to Ra=1.0μm. Machining is performed at a spindle speed of 14000r / min and a feed rate of 2200mm / min. The measured Ra after machining is approximately 1.0μm.

[0058] Region B: The target is directly set to Ra=2.5μm. Machining is performed at a spindle speed of 9000r / min and a feed rate of 3000mm / min. The measured Ra after machining is approximately 2.5μm.

[0059] Region C: The target is directly set to Ra=4.0μm. Machining is performed at a spindle speed of 5500r / min and a feed rate of 3600mm / min. The measured Ra after machining is approximately 4.0μm.

[0060] Cleaning and drying: exactly the same as step (2) in Example 1.

[0061] CVD deposition of silicon carbide coating: Deposition was performed using the same process parameters as step (3) in Example 1.

[0062] Results and Detection: Surface roughness: Measured after deposition. Region A (initial Ra = 1.0 μm) final Ra ≈ 1.32 μm (exceeding the design tolerance of 1.0 ± 0.1 μm).

[0063] Region B (initial Ra = 2.5 μm) final Ra ≈ 2.18 μm (below the design tolerance of 2.5 ± 0.1 μm).

[0064] Region C (initial Ra = 4.0 μm) has a final Ra ≈ 3.72 μm (below the design tolerance of 4.0 ± 0.1 μm).

[0065] Coating integrity: Upon observation, the coating itself was dense and uniform, without cracks. This indicates that the reason why the final product of Comparative Example 2 was unqualified was not due to defects in the coating deposition process itself, but rather because the principles of this invention were not used for reverse engineering during the machining stage, resulting in inaccurate initial roughness presets.

[0066] Yield statistics: Since the final roughness of each region did not fall within the design tolerance range, the samples prepared in this comparative example were considered unqualified, and the yield was 0%.

[0067] Conclusion: Comparative Example 2 confirms that without understanding and applying the surface roughness variation law discovered and defined in this invention for reverse engineering, even using the "machining first, coating later" approach, precise control of the final product's roughness cannot be achieved. This law is the key and necessary prerequisite for realizing the predictable and controllable preparation of this invention.

[0068] In summary, this invention provides a method for preparing graphite disks with silicon carbide coatings of various surface roughnesses, and the resulting products. The core of the method lies in discovering and defining a quantifiable variation law of surface roughness approaching a preset threshold during chemical vapor deposition. To compensate for this variation caused by the deposition process, based on this law, different regions of the graphite disk semi-finished product are reverse-engineered and targeted machined before deposition. Specifically, for the first region with a target roughness lower than the threshold, its initial roughness is preset to the target value minus a first variation; for the second region with a target roughness higher than the threshold, its initial roughness is preset to the target value plus a second variation. Thus, after deposition, a product conforming to the design targets of each region and with a complete, integral silicon carbide coating is obtained in one step. Comparison of the examples and comparative examples shows that this method fundamentally avoids the damage to the coating caused by the traditional "coating first, then processing" process, achieves accurate prediction and control of roughness, simplifies the process, and significantly improves the yield.

[0069] The above embodiments are merely illustrative of the technical concept and features of the present invention, intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and should not be construed as limiting the scope of protection of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of the present invention is defined by the appended claims rather than the foregoing description, and thus all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention.

Claims

1. A method for preparing silicon carbide coated graphite disks with multiple surface roughnesses, characterized in that, Includes the following steps: (1) Determine the target surface roughness of each region on the graphite disk surface; (2) Based on the surface roughness variation law, the initial surface roughness of the graphite disk semi-finished product applied to machining is determined by the target surface roughness of each region in reverse; wherein, the surface roughness variation law is as follows: in the subsequent chemical vapor deposition of silicon carbide coating, the surface roughness of the first region with an initial surface roughness lower than a preset threshold will increase by a first change amount after deposition, while the surface roughness of the second region with an initial surface roughness higher than the preset threshold will decrease by a second change amount after deposition; (3) Based on the determined initial surface roughness, the corresponding areas of the graphite disk semi-finished product are machined and surface pretreated; (4) Chemical vapor deposition is performed on the pre-treated graphite disk semi-finished product to form a silicon carbide coating on its surface, thereby directly obtaining a silicon carbide coated graphite disk with multiple types of target surface roughness.

2. The preparation method according to claim 1, characterized in that, The preset threshold in step (2) is between 1.5 μm and 2 μm.

3. The preparation method according to claim 1 or 2, characterized in that, In step (2), the absolute values ​​of the first change and the second change are both in the range of 0.2 μm to 0.4 μm.

4. The preparation method according to claim 3, characterized in that, In step (2), the absolute values ​​of the first change and the second change are both 0.3 μm.

5. The preparation method according to any one of claims 1 or 2, characterized in that, Step (3) The spindle speed used for machining the first area is higher than the spindle speed used for machining the second area; the feed rate used for machining the first area is lower than the feed rate used for machining the second area.

6. The preparation method according to claim 5, characterized in that, Step (3) The spindle speed of the first region is 10000~15000r / min, and the feed rate is 2000~3000mm / min; the spindle speed of the second region is 5000~9500r / min, and the feed rate is 3000~4000mm / min; the feed amount in the vertical direction of the first region and the second region is 0.2~0.25mm.

7. The preparation method according to claim 4, characterized in that, The chemical vapor deposition described in step (4) is carried out under a protective atmosphere, with the CH3SiCl3(MTS)-Ar-H2 reaction gas source system introduced. The deposition temperature is 1200~1400℃ and the deposition time is 1.5~5h. H2 is the carrier gas of MTS, and Ar is the dilution gas. The flow ratio of H2 to Ar is (5~20):1, the flow rate of Ar is 10~40L / min, and the flow rate of MTS is 10~80L / min.

8. A multi-type surface roughness silicon carbide coated graphite disk, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 7.

9. The silicon carbide coated graphite disk according to claim 8, characterized in that, The surface of the silicon carbide-coated graphite disk includes at least one first region with a roughness of 0.8~1.8μm and at least one second region with a roughness of 1.7~4.7μm, and the silicon carbide coating is an integrally formed structure without post-processing.

Images