Manufacturing process of multi-heat-dissipation base structure for MPCVD diamond growth

Abstract

The invention discloses a manufacturing process of a multi-heat dissipation base structure for MPCVD diamond growth, which comprises the following steps: S1, manufacturing a main heat dissipation jig: a heat dissipation channel is arranged at the bottom of the main heat dissipation jig, the heat dissipation channel is of a step-shaped structure which is annularly distributed, and the step-shaped structure is formed by step-by-step distribution according to gradient from the center of a base to the edge; the thickness of the main heat dissipation jig is gradually reduced from the center of the base station to the edge; s2, an auxiliary heat dissipation jig is manufactured, wherein the auxiliary heat dissipation jig is of a circular structure with two flat faces, and the thickness of the auxiliary heat dissipation jig is uniform and consistent; s3, the main heat dissipation jig is assembled above the auxiliary heat dissipation jig and used for achieving temperature uniformity during crystal growth; the method is suitable for growth of monocrystalline diamond and polycrystalline diamond, can effectively improve the temperature uniformity, and reduces the problems of crystal defects and uneven grain size distribution.

Description

Technical Field

[0001] This invention belongs to the field of microwave plasma chemical vapor deposition technology, and in particular relates to a manufacturing process for a multi-heat dissipation platform structure for MPCVD diamond growth. Background Technology

[0002] Microwave plasma chemical vapor deposition (MPCVD) is one of the main methods for preparing high-quality diamond materials, widely used in the growth of both single-crystal and polycrystalline diamond. However, during MPCVD diamond growth, the temperature uniformity of the substrate has a decisive impact on the quality of the diamond. For single-crystal diamond growth, temperature inhomogeneity leads to stress concentration within the crystal, resulting in defects such as dislocations and cracks, thus reducing the crystal's crystal quality and optical properties. For polycrystalline diamond growth, temperature inhomogeneity leads to uneven grain size distribution, affecting the mechanical properties and surface roughness of the film.

[0003] Traditional abutment structures (such as pure molybdenum abutments) often suffer from excessively high temperatures in the central region and excessively low temperatures in the peripheral region due to limitations in thermal conductivity and heat capacity. This temperature gradient leads to the following problems: In single-crystal diamond growth, excessively high temperatures in the central region may cause excessive local supersaturation, leading to non-uniform nucleation or crystal defects; excessively low temperatures in the peripheral region may cause a decrease in growth rate or even the appearance of non-diamond phases. In polycrystalline diamond deposition, excessively high temperatures in the central region may lead to excessively large grain sizes, while excessively low temperatures in the peripheral region may lead to excessively small grain sizes, resulting in non-uniform mechanical properties and surface quality of the film.

[0004] While existing technologies have introduced some improved abutment structures, such as adding cooling channels or optimizing the abutment shape, they have not fundamentally solved the problem of uneven temperature distribution. Furthermore, existing abutment materials are mostly limited to single materials (such as molybdenum), lacking adaptability to different application scenarios, such as single-crystal or polycrystalline growth. Therefore, there is an urgent need for a abutment structure capable of achieving uniform heat dissipation to meet the high-quality requirements of MPCVD diamond growth. Summary of the Invention

[0005] The purpose of this invention is to provide a manufacturing process for a multi-heat dissipation platform structure for MPCVD diamond growth, so as to effectively solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A manufacturing process for a multi-heat dissipation platform structure for MPCVD diamond growth includes the following steps: S1. Manufacturing the main heat dissipation fixture: A heat dissipation channel is provided at the bottom of the main heat dissipation fixture. The heat dissipation channel is a stepped structure distributed in a ring. The stepped structure is formed by the gradual distribution of the base from the center to the edge according to the gradient. The thickness of the main heat dissipation fixture gradually decreases from the center of the base to the edge; When manufacturing the main heat dissipation fixture, the base body is first made by machining, and then a CNC milling machine is used to machine the circumferentially distributed stepped heat dissipation channels on the base body. S2. Manufacturing auxiliary heat dissipation fixture: The auxiliary heat dissipation fixture adopts a double-sided flat circular structure, and the thickness of the auxiliary heat dissipation fixture is uniform. S3. The main heat dissipation fixture is mounted above the auxiliary heat dissipation fixture to achieve temperature uniformity during crystal growth.

[0007] Preferably, both the main heat dissipation fixture and the auxiliary heat dissipation fixture are made of one or more of molybdenum, tungsten, copper, graphite, and silicon carbide.

[0008] Preferably, both the main heat dissipation fixture and the auxiliary heat dissipation fixture are made of one or more composite materials of molybdenum, tungsten, copper, graphite, and silicon carbide.

[0009] Preferably, the main heat dissipation fixture has a circular structure.

[0010] Preferably, a ring of fencing formed around the edge of the main heat sink serves as a discharge protection structure to prevent plasma from forming a discharge.

[0011] Preferably, the edge of the main heat dissipation device is provided with positioning lines and a vacuum slit structure. The positioning lines are used to determine the orientation of the growth film in the cavity during crystal growth, and the vacuum slit structure is an airflow channel set up to ensure that the heat dissipation channel is consistent with the gas pressure in the cavity.

[0012] Preferably, the bottom of the main heat dissipation fixture is provided with a fixing hole for connecting and positioning the main heat dissipation fixture with the equipment base.

[0013] Preferably, the fixing hole is located at the bottom center of the main heat dissipation fixture, and the fixing hole has a depth of 3mm and a diameter of 5.2mm.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The multi-heat dissipation platform structure prepared by this invention is suitable for various diamond growth scenarios. Whether it is the growth of single-crystal diamond or polycrystalline diamond, it can effectively improve temperature uniformity and reduce crystal defects and uneven grain size distribution. In this invention, the base of the main heat dissipation fixture is made of a variety of high thermal conductivity materials or their composite materials to adapt to different process requirements and application scenarios, and the material selection is flexible; This invention designs a circumferentially distributed stepped structure on the main heat dissipation fixture base. Since the stepped structure is distributed stepwise from the center to the edge of the base, heat is evenly distributed. This heat dissipation structure design enables the invention to achieve a uniform temperature distribution on the sample surface in the MPCVD process, avoiding the phenomenon of excessively high temperature in the central area and excessively low temperature in the edge area, ensuring the uniformity of the sample surface temperature, and thus improving the quality of diamond growth. Attached Figure Description

[0015] Figure 1 This is a first-view view of the main heat dissipation fixture in this invention; Figure 2 This is a second-view view of the main heat dissipation fixture in this invention; Figure 3 This is a schematic diagram of the auxiliary heat dissipation fixture in this invention; Figure 4 This is an assembly drawing of the main heat dissipation fixture and the auxiliary heat dissipation fixture in this invention; Detailed Implementation

[0016] The technical solution of the present invention will be described in detail below with reference to the embodiments, but the scope of protection is not limited thereto. Example

[0017] A manufacturing process for a multi-heat dissipation platform structure for MPCVD diamond growth includes the following steps: S1. Manufacturing the main heat dissipation fixture: such as... Figure 1 and Figure 2 As shown, a heat dissipation channel is provided at the bottom of the main heat dissipation fixture. The heat dissipation channel is a stepped structure distributed in a ring direction. The stepped structure is formed by the gradual distribution of the base from the center to the edge according to the gradient. The thickness of the main heat dissipation fixture gradually decreases from the center of the base to the edge; The main heat dissipation fixture is made of high-purity molybdenum material, with a diameter of 80 mm and a maximum thickness of 5.5 mm. The base body is first machined, and then a CNC milling machine is used to machine circumferentially distributed stepped heat dissipation channels on the base body of the main heat dissipation fixture. The thickness of each step from the center to the edge is 5.5 mm, 5.2 mm, 4.9 mm, 4.5 mm, 4.1 mm, 3.5 mm, and 5.5 mm, respectively. A fixing hole with a depth of 3 mm and a diameter of 5.2 mm is left at the center of the bottom of the main heat dissipation fixture. S2. Manufacturing auxiliary heat dissipation fixtures: such as Figure 3 As shown, the auxiliary heat dissipation fixture adopts a double-sided flat circular structure, and the thickness of the auxiliary heat dissipation fixture is uniform. The auxiliary heat dissipation fixture is made of high-purity molybdenum material, with a diameter of 80 mm and a thickness of 3 mm. A fixing hole with a diameter of 5.2 mm is left at the center of the bottom of the auxiliary heat dissipation fixture and runs vertically through the fixture. S3, such as Figure 4 As shown, the main heat dissipation fixture is mounted above the auxiliary heat dissipation fixture to achieve temperature uniformity during crystal growth.

[0018] MPCVD diamond growth experiment: Sample placement: Place the single-crystal diamond substrates (10 mm × 10 mm in size, 18 pcs) evenly on the base of the main heat dissipation fixture; Experimental equipment: Microwave plasma chemical vapor deposition equipment was used; Process parameters: microwave power is 5.5 kW, reaction gases are methane and hydrogen, methane concentration is 2.5%, hydrogen gas flow rate is 200 sccm, reaction pressure is 105 torr, and growth time is 20 hours; Experimental results: Temperature distribution: The surface temperature distribution of the main heat dissipation fixture was measured by infrared thermal imaging. The results showed that the surface temperature uniformity of the sample was significantly improved, with the temperature difference between the central and edge regions being less than 10°C, while the temperature difference of traditional fixtures usually exceeds 30°C. Example

[0019] A manufacturing process for a multi-heat dissipation platform structure for MPCVD diamond growth includes the following steps: S1. Manufacturing the main heat dissipation fixture: such as... Figure 1 and Figure 2 As shown, a heat dissipation channel is provided at the bottom of the main heat dissipation fixture. The heat dissipation channel is a stepped structure distributed in a ring direction. The stepped structure is formed by the gradual distribution of the base from the center to the edge according to the gradient. The thickness of the main heat dissipation fixture gradually decreases from the center of the base to the edge; The main heat dissipation fixture is made of high-purity molybdenum material, with a diameter of 80 mm and a maximum thickness of 6 mm. The top has a ring wall with a diameter of 77 mm, an outer diameter of 80 mm, and a width of 2 mm as a discharge protection structure. The discharge protection structure is used to prevent plasma from forming a discharge. First, the base body is manufactured by machining. Then, a CNC milling machine is used to machine a stepped heat dissipation channel distributed in a ring on the base body of the main heat dissipation fixture. The thickness of each step from the center to the edge is 5.5mm, 5.2mm, 4.9mm, 4.5mm, 4.1mm, 3.5mm, and 5.5mm respectively. A fixing hole with a depth of 3mm and a diameter of 5.2mm is left at the center of the bottom of the main heat dissipation fixture. The edge of the main heat dissipation device is provided with positioning lines and a vacuum slit structure. The positioning lines are used to determine the orientation of the growth film in the cavity during crystal growth. The vacuum slit structure is an airflow channel set up to ensure that the heat dissipation channel is consistent with the gas pressure in the cavity. S2. Manufacturing auxiliary heat dissipation fixtures: such as Figure 3 As shown, the auxiliary heat dissipation fixture adopts a double-sided flat circular structure, and the thickness of the auxiliary heat dissipation fixture is uniform. The auxiliary heat dissipation fixture is made of high-purity molybdenum material, with a diameter of 80 mm and a thickness of 3 mm. A fixing hole with a diameter of 5.2 mm is left at the center of the bottom of the auxiliary heat dissipation fixture and runs vertically through the fixture. S3, such as Figure 4 As shown, the main heat dissipation fixture is mounted above the auxiliary heat dissipation fixture to achieve temperature uniformity during crystal growth.

[0020] MPCVD diamond polycrystalline growth experiment: Sample placement: Fix the auxiliary heat dissipation fixture to the equipment stage, place the main heat dissipation fixture above the auxiliary heat dissipation fixture and align it, and place the 3-inch 2mm thick substrate for growing diamond polycrystalline on the groove on the surface of the main heat dissipation fixture.

[0021] Experimental equipment: Microwave plasma chemical vapor deposition equipment was used; Process parameters: microwave power is 9 kW, reaction gases are methane and hydrogen, methane concentration is 2%, hydrogen gas flow rate is 300 sccm, reaction pressure is 110 torr, and growth time is 20 hours. Experimental results: Temperature distribution: The surface temperature distribution of the substrate was measured by an infrared thermal imager. The results showed that the surface temperature uniformity of the sample was significantly improved, with the temperature difference between the central and edge regions being less than 10°C, while the temperature difference of traditional substrates usually exceeds 30°C.

[0022] The above embodiments demonstrate that the multi-heat dissipation platform structure provided by the present invention can effectively improve the temperature uniformity during the MPCVD diamond growth process, thereby improving the quality of single-crystal and polycrystalline diamonds. This platform structure has advantages such as simple manufacturing process, significant heat dissipation effect, and wide applicability, and has important industrial application value.

[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A manufacturing process for a multi-heat dissipation platform structure for MPCVD diamond growth, characterized in that, Includes the following steps, S1. Manufacturing the main heat dissipation fixture: A heat dissipation channel is provided at the bottom of the main heat dissipation fixture. The heat dissipation channel is a stepped structure distributed in a ring. The stepped structure is formed by the gradual distribution of the base from the center to the edge according to the gradient. The thickness of the main heat dissipation fixture gradually decreases from the center of the base to the edge; When manufacturing the main heat dissipation fixture, the base body is first made by machining, and then a CNC milling machine is used to machine the circumferentially distributed stepped heat dissipation channels on the base body. S2. Manufacturing auxiliary heat dissipation fixture: The auxiliary heat dissipation fixture adopts a double-sided flat circular structure, and the thickness of the auxiliary heat dissipation fixture is uniform. S3. The main heat dissipation fixture is mounted above the auxiliary heat dissipation fixture to achieve temperature uniformity during crystal growth.

2. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 1, characterized in that, Both the main heat dissipation fixture and the auxiliary heat dissipation fixture are made of one or more of molybdenum, tungsten, copper, graphite, and silicon carbide.

3. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 1, characterized in that, Both the main heat dissipation fixture and the auxiliary heat dissipation fixture are made of one or more composite materials of molybdenum, tungsten, copper, graphite, and silicon carbide.

4. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 1, characterized in that, The main heat dissipation fixture has a circular structure.

5. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 1, characterized in that, A ring of fencing is machined around the top edge of the main heat sink as a discharge protection structure to prevent plasma from forming a discharge.

6. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 1, characterized in that, The edge of the main heat dissipation device is provided with positioning lines and a vacuum slit structure. The positioning lines are used to determine the orientation of the growth film in the cavity during crystal growth, and the vacuum slit structure is an airflow channel set up to ensure that the heat dissipation channel is consistent with the gas pressure in the cavity.

7. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 1, characterized in that, The bottom of the main heat dissipation fixture is provided with a fixing hole for connecting and positioning the main heat dissipation fixture to the equipment base.

8. The manufacturing process of the multi-heat dissipation platform structure for MPCVD diamond growth according to claim 7, characterized in that, The fixing hole is located at the bottom center of the main heat dissipation fixture, with a depth of 3mm and a diameter of 5.2mm.

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