A deposition station, a method for producing a large-size diamond film

Abstract

The application belongs to the field of semiconductor materials, and specifically discloses a deposition table and a preparation method of a large-size diamond film. The deposition table comprises a substrate, a transition layer, a blocking ring, a molybdenum ring and a base, the substrate, the transition layer and the base are sequentially arranged from top to bottom, and the substrate, the transition layer and the base are concentrically arranged; the molybdenum ring is sleeved on the outer peripheral wall of a cylinder formed by the substrate, the transition layer and the base; a side wall of the substrate is provided with a radial insertion slot one; the blocking ring is inserted into the insertion slot one, and the blocking ring is arranged along the radial direction of the substrate. The transition layer is used for regulating heat conduction and interface thermal resistance, balancing the temperature gradient of the substrate, improving the uniformity of the global temperature field, and ensuring uniform crystal growth; the blocking ring is used for preventing the growth of polycrystals on the side of the substrate molybdenum table, preventing the diamond from being broken due to side edge wrapping when the diamond is separated from the substrate, reducing the risk of fragmentation, realizing low-stress high-quality film formation, and improving the yield and reliability of large-size diamond film preparation.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor materials and relates to the production of diamond films, specifically to a deposition stage and a method for preparing large-size diamond films. Background Technology

[0002] Diamond possesses excellent optical and thermal conductivity properties, making it valuable for applications in high-end heat sinks, optical windows, and numerous advanced technologies. Traditional methods such as hot-wire CVD and DC arc CVD easily introduce impurities into diamonds, resulting in lower thermal conductivity and optical transmittance, which fails to meet the demands of high-end applications. Microwave plasma CVD (MPCVD), due to its high energy density and absence of electrode contamination, has become the preferred method for producing high-quality diamonds.

[0003] Currently, high-quality polycrystalline diamond films are generally grown on silicon wafers using MPCVD equipment. Due to the influence of the deposition stage structure and plasma field distribution, the temperature field at the substrate edge is uneven, causing warping of the diamond film and silicon wafer, stress concentration, and making the finished product prone to breakage during processing, resulting in a low overall yield. Furthermore, after growth, an acid-base etching process is required to remove the silicon substrate to obtain a self-supporting diamond film.

[0004] The current method of using acid and alkali etching to remove silicon substrates is complex and lengthy, significantly extending the production cycle. The continuous use of large quantities of strong acid and alkali reagents directly increases raw material consumption and post-processing costs, while reducing production economics. The highly corrosive reagents pose safety hazards during operation, and the treatment of byproducts and wastewater also brings additional environmental pressure. More importantly, the existing deposition stage structure cannot effectively suppress edge effects, resulting in poor temperature field uniformity, high internal stress in the diamond film, and easy edge breakage, further reducing the yield and hindering the stable preparation of large-size, high-quality self-supporting diamond films. Summary of the Invention

[0005] In view of the defects and deficiencies of the existing technology, the present invention provides a deposition stage in the first aspect; and a method for preparing large-size diamond films in the second aspect.

[0006] In a first aspect, the present invention provides a deposition stage, comprising a substrate, a transition layer, a stop ring, a molybdenum ring, and a base, wherein the substrate, the transition layer, and the base are arranged sequentially from top to bottom, and the substrate, the transition layer, and the base are concentrically arranged; The molybdenum ring is sleeved on the outer peripheral wall of the column formed by the substrate, the transition layer and the base; The substrate has a radially extending insertion groove on its sidewall; The blocking ring is inserted into the first insertion slot, and the blocking ring is arranged radially along the substrate.

[0007] Preferably, the transition layer is a metal thin film.

[0008] More preferably, the transition layer is any one or more of copper, silver, nickel, and titanium.

[0009] Preferably, the thickness of the transition layer is 0.02~0.1mm.

[0010] Preferably, the substrate is any one or both of molybdenum and tungsten.

[0011] Preferably, the substrate has a diameter ≥ 6 inches, a thickness ≥ 7 mm, a roughness ≤ 10 nm, and a crystal orientation of [missing information]. <100> .

[0012] Preferably, the blocking ring is made of an ferrous metal.

[0013] More preferably, the blocking ring is any one or more of iron, cobalt, and nickel.

[0014] Secondly, the present invention provides a method for preparing a large-size diamond film, which is prepared using the above-mentioned deposition stage and includes the following steps: Step 1: Clean the substrate, and then place the substrate in a vacuum atmosphere to deposit a transition substrate film; Step 2: Place the substrate after the coating process into the MPCVD equipment for bias nucleation and growth processes in sequence; Step 3: Anneal the film grown in Step 2 to obtain the large-size diamond film.

[0015] Preferably, in step 1, during cleaning, acetone, anhydrous ethanol, and pure water are used sequentially for ultrasonic cleaning, and the cleaning is repeated 3 times, with each cleaning agent cleaning for 2-3 minutes.

[0016] Preferably, in step 1, the coating process is either electron beam evaporation or magnetron sputtering.

[0017] Preferably, in step 1, the transition substrate film is any one or two of iridium film, silicon film, and titanium film.

[0018] Preferably, in step 1, the coating thickness is 0.5~10μm, and the coating crystal orientation is... <100> .

[0019] Preferably, during bias nucleation in step 2, the volume ratio of methane to hydrogen in the reaction chamber is (4%~6%):1, the hydrogen flow rate is 1800~2500 sccm, the pressure is 20~25 kPa, the temperature is 700~750℃, the bias voltage is (-200)~(-150) V, and the bias duration is 1~3 h.

[0020] Preferably, during growth in step 2, a mixture of methane, hydrogen, and trace amounts of oxygen is continuously introduced into the reaction chamber. The volume ratio of methane to hydrogen in the reaction chamber is controlled to be (2.5%~4.5%):1, the hydrogen flow rate is 1800~4000 sccm, the volume ratio of oxygen to hydrogen is (0.05%~0.15%):1, the power is 45~65 kW, the temperature is 800~950℃, the pressure is 21~26 kPa, and the growth time is 500~1000 h.

[0021] Preferably, in step 3, the methane concentration in the reaction system is controlled to be 0, and then the temperature is maintained at 1000~1200℃ for 1~2h, then the temperature is lowered to 600~500℃ at 3~4℃ / min, and then lowered to room temperature at 1~2℃ / min. At this time, the diamond film automatically detaches from the substrate.

[0022] Compared with the prior art, one or more technical solutions provided by the present invention have at least one of the following beneficial effects: (1) This invention regulates heat conduction and interfacial thermal resistance through a transition layer, balances the substrate temperature gradient, improves the uniformity of the global temperature field, and ensures uniform grain growth. At the same time, it uses a stop ring to prevent the growth of polycrystalline material on the side of the substrate molybdenum stage, prevents diamond from cracking when the diamond separates from the substrate due to the side edge covering, reduces the risk of breakage, achieves low-stress high-quality film formation, and significantly improves the yield and reliability of large-size diamond film preparation.

[0023] (2) In this invention, a low-stress, high-quality nucleation interface is first constructed by preparing a gradient composite coating of titanium film, silicon film and iridium film on a substrate; then, the hydrocarbon gas is cracked by MPCVD microwave plasma, and a dense polycrystalline diamond film is formed by high-density nucleation under bias and steady-state epitaxial growth; finally, the thermal expansion mismatch of the multilayer coating and the anti-ring stress guiding effect are used to achieve automatic demolding and molding without corrosion during the cooling process. Attached Figure Description

[0024] Figure 1 A schematic cross-sectional view of the deposition stage provided in Example 1; Figure 2 for Figure 1 A magnified structural diagram of part A in the middle.

[0025] Figure descriptions: 1. Substrate; 2. Transition layer; 3. Stop ring; 4. Molybdenum ring; 5. Base; 6. Insertion slot one. Detailed Implementation

[0026] The present invention provides the following specific technical solutions.

[0027] In a first aspect, the present invention provides a deposition stage, comprising a substrate, a transition layer, a stop ring, a molybdenum ring, and a base, wherein the substrate, the transition layer, and the base are arranged sequentially from top to bottom, and the substrate, the transition layer, and the base are concentrically arranged; The molybdenum ring is sleeved on the outer peripheral wall of the column formed by the substrate, the transition layer and the base; The substrate has a radially extending insertion groove on its sidewall; The blocking ring is inserted into the first insertion slot, and the blocking ring is arranged radially along the substrate.

[0028] Through research, the inventors discovered that, addressing the technical shortcomings of existing large-size diamond film fabrication processes such as uneven substrate temperature, severe edge effects caused by edge electric field distortion, stress concentration within the film layer, and brittleness and detachment of the finished product, this invention employs a metal transition layer to precisely control the thermal conductivity rate and interface thermal resistance matching. This efficiently balances the temperature gradient difference between the substrate center and edge, significantly improving the uniformity and stability of the temperature field across the entire growth surface of large-size diamond films. This ensures consistent diamond grain nucleation and growth rates and uniform and controllable crystal quality. Simultaneously, relying on radially inserted stop rings to directionally prevent the growth of polycrystalline material on the side of the substrate molybdenum stage, it prevents diamond breakage due to side edge detachment from the substrate. This collaboratively avoids the risk of breakage during finished product processing. Low-stress, high-quality film formation and stable growth can be achieved without strong acid or alkali corrosion, comprehensively improving the yield and mechanical reliability of large-size, high-quality diamond film deposition on a large scale.

[0029] Preferably, the transition layer is a metal thin film.

[0030] More preferably, the transition layer is any one or more of copper, silver, nickel, and titanium.

[0031] Through research, the inventors discovered that copper and silver have extremely high thermal conductivity, while nickel and titanium are well-suited to thermal resistance gradients. This allows them to quickly level out the temperature difference between the center and edge of large-size substrates, mitigating the uneven growth rate caused by temperature gradients and resulting in more consistent crystal quality throughout the substrate. Combined with a stop ring structure, this prevents the growth of polycrystalline material on the sides of the molybdenum stage, preventing diamond breakage due to side edging when the diamond detaches from the substrate. This facilitates corrosion-free, low-damage whole-piece demolding.

[0032] Preferably, the thickness of the transition layer is 0.02~0.1mm.

[0033] Preferably, the substrate is made of any one or two of molybdenum and titanium.

[0034] Through research, the inventors discovered that using molybdenum, titanium, and their composite materials as substrates can maintain flatness and dimensional accuracy and suppress warping thermal deformation during long-duration, high-power MPCVD deposition, while possessing high thermal conductivity, excellent high-temperature mechanical stability, and low high-temperature deformation rate.

[0035] Preferably, the substrate has a diameter ≥ 6 inches, a thickness ≥ 7 mm, a roughness ≤ 10 nm, and a crystal orientation of [missing information]. <100> .

[0036] The inventors discovered through research that the substrate diameter is limited to ≥6 inches, thickness to ≥7 mm, roughness to ≤10 nm, and with preferred orientation. <100> This ensures uniform stress across the entire large area, dense interface bonding, and controllable low-defect nucleation sites, while improving the uniformity of diamond film grain orientation, thickness uniformity, and mechanical integrity. This facilitates subsequent low-stress whole-piece demolding and large-scale high-yield fabrication.

[0037] Preferably, the blocking ring is made of an ferrous metal.

[0038] Through research, the inventors discovered that, thanks to its strong carbon solubility and controllable carbon precipitation characteristics, it prevents the formation of polycrystalline diamonds on the rings, thus blocking the growth of polycrystalline diamonds on the sides. This prevents the diamonds from cracking due to the edge wrapping when they detach from the substrate, reducing the edge breakage rate and ensuring stable preparation with low stress flattening and high yield.

[0039] More preferably, the blocking ring is any one or more of iron, cobalt, and nickel.

[0040] Secondly, the present invention provides a method for preparing a large-size diamond film, which is prepared using the above-mentioned deposition stage and includes the following steps: Step 1: Clean the substrate, and then place the substrate in a vacuum atmosphere to deposit a transition substrate film; Step 2: Place the substrate after the coating process into the MPCVD equipment for bias nucleation and growth processes in sequence; Step 3: Anneal the film grown in Step 2 to obtain the large-size diamond film.

[0041] Through research, the inventors discovered that a low-stress, high-quality nucleation interface is first constructed by preparing a transition base film on a substrate; then, hydrocarbon gas is cracked by MPCVD microwave plasma, followed by high-density nucleation under bias and steady-state epitaxial growth, layer by layer, to form a dense polycrystalline diamond film; finally, the thermal expansion mismatch of the multilayer coating and the blocking effect of the stop ring are utilized to achieve corrosion-free automatic demolding during the cooling process.

[0042] Preferably, in step 1, during cleaning, acetone, anhydrous ethanol, and pure water are used sequentially for ultrasonic cleaning, and the cleaning is repeated 3 times, with each cleaning agent cleaning for 2-3 minutes.

[0043] Preferably, in step 1, the coating process is either electron beam evaporation or magnetron sputtering.

[0044] Preferably, in step 1, the transition substrate film is any one or two of iridium film, silicon film, and titanium film.

[0045] Preferably, in step 1, the coating thickness is 5~10μm, and the coating crystal orientation is... <100> .

[0046] Preferably, during bias nucleation in step 2, the volume ratio of methane to hydrogen in the reaction chamber is (4%~6%):1, the hydrogen flow rate is 1800~2500 sccm, the pressure is 20~25 kPa, the temperature is 700~750℃, the bias voltage is (-200)~(-150) V, and the bias duration is 1~3 h.

[0047] Preferably, during growth in step 2, a mixture of methane, hydrogen, and trace amounts of oxygen is continuously introduced into the reaction chamber. The volume ratio of methane to hydrogen in the reaction chamber is controlled to be (2.5%~4.5%):1, the hydrogen flow rate is 1800~4000 sccm, the volume ratio of oxygen to hydrogen is (0.05%~0.15%):1, the power is 45~65 kW, the temperature is 800~950℃, the pressure is 21~26 kPa, and the growth time is 500~1000 h.

[0048] Preferably, in step 3, the methane concentration in the reaction system is controlled to be 0, and then the temperature is maintained at 1000~1200℃ for 1~2h, then the temperature is lowered to 600~500℃ at 3~4℃ / min, and then lowered to room temperature at 1~2℃ / min. At this time, the diamond film automatically detaches from the substrate.

[0049] Through research, the inventors discovered that this stepped temperature-controlled annealing process can not only fully eliminate residual thermal stress and lattice defects in diamond film growth and improve crystal integrity and mechanical stability, but also accurately amplify the controllable thermal expansion mismatch gradient between multiple coating layers and directionally induce uniform shearing and peeling at the interface, avoiding sudden cooling cracking, warping and edge chipping, achieving corrosion-free, low-damage, flat and automatic demolding, significantly simplifying the post-processing process and improving the yield of large-size products.

[0050] To make the technical problems, technical solutions and technical advantages of the present invention clearer, a detailed description will be given below with reference to specific examples. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0051] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0052] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0053] Example 1: A deposition stage includes a substrate 1, a transition layer 2, a stop ring 3, a molybdenum ring 4, and a base 5. The substrate 1, the transition layer 2, and the base 5 are arranged sequentially from top to bottom and are concentrically arranged. The molybdenum ring 4 is sleeved on a column formed by the substrate 1, the transition layer 2, and the base 5. The substrate 1, the transition layer 2, and the base 5 have the same diameter. The molybdenum ring 4 is adapted to the substrate 1, and the molybdenum ring 4 is fixedly fitted to the column formed by the substrate 1 and the transition layer 2.

[0054] The blocking ring 3 is arranged along the radial direction of the substrate 1; the substrate 1 has an insertion groove 6 for the blocking ring 3 to be inserted.

[0055] Substrate 1 is any one or both of molybdenum and tungsten, with a purity ≥99.99%, a diameter ≥6 inches, a thickness ≥7 mm, a roughness ≤10 nm, and a crystal orientation of [missing information]. <100> .

[0056] The transition layer 2 is a metal thin film, which can be any one or more of copper, silver, nickel, and titanium.

[0057] The blocking ring 3 is an iron-based metal, and the blocking ring 3 is any one or more of iron, cobalt, and nickel.

[0058] In practical applications, the dimensions of each structure in the deposition stage can be adjusted according to actual needs. In a specific embodiment of the present invention, the substrate 1 has a diameter of 6 inches and a height of 7 mm; the transition layer 2 has a thickness of 0.02 mm and a diameter equal to that of the substrate 1; the base 5 has a diameter of the substrate 1 plus 1 mm and a thickness of 15 mm; the stop ring 3 has an inner diameter of 149 mm, an outer diameter of the stop ring 3 is the substrate 1 diameter plus 1.2 mm, a height of 1 mm, and a height difference of 0.1 mm between the upper surface of the stop ring 3 and the upper surface of the substrate 1; the molybdenum ring 4 has an inner diameter of 156 mm and an outer diameter ≥ the substrate 1 diameter + 20 mm.

[0059] Example 2: A method for preparing a large-size diamond film includes the following steps: Step 1: Use acetone, anhydrous ethanol, and pure water to ultrasonically clean the substrate in sequence, and cycle the cleaning process 3 times, cleaning for 3 minutes with each cleaning agent.

[0060] Step 2: Place the substrate in a vacuum atmosphere and deposit a 5μm thick silicon film using magnetron sputtering. The deposition temperature is 400℃, the pressure is 1Pa, and the crystal orientation of the silicon film is [missing information]. <100> .

[0061] Step 3: Place the substrate processed in Step 2 into a 915MHz-MPCVD device for bias nucleation. The volume ratio of methane to hydrogen is 4%:1, the hydrogen flow rate is 1800sccm, the pressure is 20kPa, the temperature is 700℃, the bias voltage is -200V, and the bias duration is 1h.

[0062] Step 4: After bias nucleation, high-power-density growth begins. The equipment cavity remains sealed and hydrogen is continuously supplied. The equipment process parameters are adjusted to the growth conditions, with the equipment output power set at 45kW, the cavity growth temperature at 800℃, and the cavity working pressure at 21kPa. A mixture of methane, hydrogen, and trace amounts of oxygen is continuously supplied into the cavity. The gas ratio is precisely controlled, maintaining a constant hydrogen flow rate of 1800sccm. The volume ratio of methane to hydrogen is controlled at 2.5%:1, and the volume ratio of oxygen to hydrogen is controlled at 0.05%:1. Under the above process conditions, the continuous growth time is 500h.

[0063] Step 5, Annealing and Cooling, and Automatic Demolding: After the diamond film deposition and growth process in Step 4 is completed, keep the equipment cavity sealed and gradually reduce the amount of methane gas entering the cavity until the methane concentration drops to 0. Then, shut off the gas sources of methane, oxygen, and hydrogen. Subsequently, raise the cavity temperature to 1000℃ and hold it at that temperature for 1.5 hours to eliminate the growth stress inside the diamond film and optimize the crystallization performance of the film layer. After the holding period, control the cavity to cool down to 500℃ at a uniform cooling rate of 3℃ / min. After reaching the temperature node, adjust the cooling rate to 1℃ / min and slowly cool down to room temperature. Throughout the entire cooling process, keep the cavity sealed and maintain a stable process atmosphere. After the cooling is completed, open the cavity and remove the substrate. Under the stress release effect, the diamond film automatically and completely separates from the substrate, thus completing the preparation of the large-size diamond film and the non-destructive demolding.

[0064] Example 3: A method for preparing a large-size diamond film includes the following steps: Step 1: Use acetone, anhydrous ethanol, and pure water to ultrasonically clean the substrate in sequence, and cycle the cleaning process 3 times, cleaning for 2 minutes with each cleaning agent.

[0065] Step 2: Place the substrate in a vacuum atmosphere and deposit a 5μm thick iridium film using electron beam evaporation. The deposition temperature is 600℃ and the pressure is 10. -4 Pa, the crystal orientation of the iridium film is <100> .

[0066] Step 3: Place the substrate processed in Step 2 into a 915MHz-MPCVD device for bias nucleation. The volume ratio of methane to hydrogen is 6%:1, the hydrogen flow rate is 2500sccm, the pressure is 25kPa, the temperature is 750℃, the bias voltage is -150V, and the bias duration is 3h.

[0067] Step 4: After bias nucleation, high-power-density growth begins. The equipment cavity remains sealed, and hydrogen is continuously supplied. The process parameters are adjusted to the desired growth conditions, setting the equipment output power to 65kW, the cavity growth temperature to 950℃, and the cavity working pressure to 26kPa. A mixture of methane, hydrogen, and trace amounts of oxygen is continuously introduced into the cavity. The gas ratio is precisely controlled, maintaining a constant hydrogen flow rate of 4000 sccm. The volume ratio of methane to hydrogen is controlled at 4.5%:1, and the volume ratio of oxygen to hydrogen at 0.15%:1. Under these process conditions, the continuous growth time is 500 hours.

[0068] Step 5, Annealing and Cooling, and Automatic Demolding: After the diamond film deposition and growth process in Step 4 is completed, keep the equipment cavity sealed and gradually reduce the amount of methane gas entering the cavity until the methane concentration drops to 0. Then, shut off the gas sources of methane, oxygen, and hydrogen. Subsequently, raise the cavity temperature to 1100℃ and hold it at that temperature for 1.5 hours to eliminate the growth stress inside the diamond film and optimize the crystallization performance of the film layer. After the holding period, control the cavity to cool down to 600℃ at a uniform cooling rate of 4℃ / min. After reaching the temperature node, adjust the cooling rate to 2℃ / min and slowly cool down to room temperature. Throughout the entire cooling process, keep the cavity sealed and maintain a stable process atmosphere. After the cooling is completed, open the cavity and remove the substrate. Under the stress release effect, the diamond film automatically and completely separates from the substrate, thus completing the preparation of the large-size diamond film and the non-destructive demolding.

[0069] Example 4: A method for preparing a large-size diamond film includes the following steps: Step 1: Use acetone, anhydrous ethanol, and pure water to ultrasonically clean the substrate in sequence, and cycle the cleaning process 3 times, cleaning for 2 minutes with each cleaning agent.

[0070] Step 2: Place the substrate in a vacuum atmosphere and deposit a 10 μm thick titanium film using magnetron sputtering. The deposition temperature is 800℃ and the pressure is 1 Pa. The crystal orientation of the titanium film is... <100> .

[0071] Step 3: Place the substrate processed in Step 2 into a 915MHz-MPCVD device for bias nucleation. The volume ratio of methane to hydrogen is 5%:1, the hydrogen flow rate is 2200sccm, the pressure is 23kPa, the temperature is 725℃, the bias voltage is -175V, and the bias duration is 2h.

[0072] Step 4: After bias nucleation, high-power-density growth begins. The equipment cavity remains sealed and hydrogen is continuously supplied. The equipment process parameters are adjusted to the growth conditions, with the equipment output power set at 55kW, the cavity growth temperature at 900℃, and the cavity working pressure at 23kPa. A mixture of methane, hydrogen, and trace amounts of oxygen is continuously introduced into the cavity. The gas ratio is precisely controlled, maintaining a constant hydrogen flow rate of 1800sccm. The volume ratio of methane to hydrogen is controlled at 3.5%:1, and the volume ratio of oxygen to hydrogen is controlled at 0.1%:1. Under the above process conditions, the continuous growth time is 500h.

[0073] Step 5, Annealing and Cooling, and Automatic Demolding: After the diamond film deposition and growth process in Step 4 is completed, keep the equipment cavity sealed and gradually reduce the amount of methane gas entering the cavity until the methane concentration drops to 0. Then, shut off the gas sources of methane, oxygen, and hydrogen. Subsequently, raise the cavity temperature to 1200℃ and hold it at that temperature for 2 hours to eliminate the growth stress inside the diamond film and optimize the crystallization performance of the film layer. After the holding period, control the cavity to cool down to 550℃ at a uniform cooling rate of 4℃ / min. After reaching the temperature node, adjust the cooling rate to 2℃ / min and slowly cool down to room temperature. Throughout the entire cooling process, keep the cavity sealed and maintain a stable process atmosphere. After the cooling is completed, open the cavity and remove the substrate. Under the stress release effect, the diamond film automatically and completely separates from the substrate, thus completing the preparation of the large-size diamond film and the non-destructive demolding.

[0074] Comparative Example 1: A deposition stage, which differs from Example 1 in that it does not have a stop ring.

[0075] A method for preparing a large-size diamond film, using the above-mentioned deposition stage without a stop ring, is exactly the same as in Example 2.

[0076] Comparative Example 2: A deposition stage, which differs from Example 1 in that it does not have a transition substrate silicon film.

[0077] A method for preparing a large-size diamond film, using the above-mentioned deposition stage without a transition substrate silicon film, is exactly the same as in Example 2.

[0078] Comparative Example 3: A method for preparing a large-size diamond film differs from Example 2 in that, in step 3, the substrate treated in step 2 is placed in a bias-voltage 915MHz-MPCVD device for bias nucleation. The volume ratio of methane to hydrogen is 1%:1, the hydrogen flow rate is 1800 sccm, the pressure is 18 kPa, the temperature is 650℃, the bias voltage is -100V, and the bias duration is 1 h.

[0079] Comparative Example 4: A method for preparing a large-size diamond film differs from Example 2 in that, in step 3, the substrate treated in step 2 is placed in a bias-voltage 915MHz-MPCVD device for bias nucleation. The volume ratio of methane to hydrogen is 7%:1, the hydrogen flow rate is 3000 sccm, the pressure is 27 kPa, the temperature is 800℃, the bias voltage is -50V, and the bias duration is 1 h.

[0080] Comparative Example 5: A method for preparing a large-size diamond film differs from Example 2 in that, in step 4, after bias nucleation, high-power-density growth is performed at a power of 30kW, a temperature of 700℃, a pressure of 19kPa, a volume ratio of methane to hydrogen of 1.5%:1, a hydrogen flow rate of 1800sccm, a volume ratio of oxygen to hydrogen of 0.01%:1, and a growth time of 500h.

[0081] Comparative Example 6: A method for preparing a large-size diamond film differs from Example 2 in that, in step 4, after bias nucleation, high-power-density growth is performed at a power of 70kW, a temperature of 1000℃, a pressure of 28kPa, a volume ratio of methane to hydrogen of 6%:1, a hydrogen flow rate of 5000sccm, a volume ratio of oxygen to hydrogen of 0.4%:1, and a growth time of 500h.

[0082] The diamond films prepared in Examples 2-4 and Comparative Examples 1-6 were subjected to performance tests, and the test data are shown in Table 1.

[0083] Table 1 Performance parameters of diamond films obtained in Examples 2-4 and Comparative Examples 1-6 As shown in Table 1, the full width at half maximum (FWHM) of the Raman peaks in Examples 2, 3, and 4 is only 2.61~2.83 cm. -1 The D peak shifted by 0.3~0.51cm. -1 This demonstrates that the transition layer structure, blocking ring, and combination of bias nucleation and oxygen-doped growth parameters defined in this invention can significantly suppress sp. 2 The removal of graphite impurities and reduction of lattice defects significantly improves the purity of diamond crystals.

[0084] The deposition stage of Comparative Example 1 did not have a stop ring. Its growth rate, crystal quality, and warpage were similar to those of the Example, but it could not be completely demolded. The lack of a radial stop ring could not block the growth of diamond polycrystalline on the side of the substrate. The edge of the film and the molybdenum substrate formed a side-edge structure. During annealing and peeling, the edges stuck together and could not be detached as a whole, which limited the processing of the finished product.

[0085] In Comparative Example 2, no metallic transition substrate film was placed on the deposition stage, and the Raman full width at half maximum (FWHM) of the diamond film increased to 3.58 cm.-1 D peak shift 0.68cm -1 The number of crystal defects increases significantly; the thickness difference and warpage deteriorate simultaneously; the substrate has no transition layer and cannot balance the temperature gradient across the entire area; the growth difference between the center and the edge is large, and stress concentration occurs; not only can it not be completely demolded, but the film will also break during the demolding process; the thermal resistance of the interface without a transition layer is mismatched, the thermal expansion is mismatched and unbalanced, and stress concentration during peeling tears the diamond film.

[0086] In Comparative Example 3, the nucleation density was insufficient during the preparation of the diamond film, resulting in a deposition rate of only 1.31 μm / h and a thinner film thickness; the Raman full width at half maximum (FWHM) was 3.41 cm. -1 The defects increased significantly; although it could be completely demolded, the crystal quality and growth efficiency were significantly inferior to the example.

[0087] In Comparative Example 4, excessively high carbon source concentration during diamond film preparation induced the formation of numerous impurity crystals, increasing the thickness difference to 74.2 μm, and causing the warpage to surge to 110.2 μm, resulting in a sharp increase in intrafilm stress; crystallinity indicators deteriorated (half-width at half maximum 3.65 cm). -1 Furthermore, excessive polycrystalline growth at the edges prevents complete demolding.

[0088] In Comparative Example 5, during the preparation of diamond films, the microwave power was insufficient, the plasma activity was low, the hydrocarbon dissociation was incomplete, and the trace oxygen was insufficient to etch graphite impurities; the expected performance was: low growth rate, thin film thickness, significant Raman defect peaks, and poor thickness uniformity.

[0089] In Comparative Example 6, during the preparation of diamond films, excessive power resulted in excessively strong plasma energy, and high temperature exacerbated lattice distortion; excessive methane generated a large amount of graphite, and excessive oxygen etched the diamond matrix in the reverse direction; the expected results were: a significant increase in warpage, stress explosion of the film layer, severe edge damage, inability to completely demold, and a sharp decline in crystal quality.

[0090] The above-described embodiments are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope of the present invention, based on the technical solution and concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A sedimentation stage, characterized in that, It includes a substrate (1), a transition layer (2), a stop ring (3), a molybdenum ring (4), and a base (5). The substrate (1), the transition layer (2), and the base (5) are arranged sequentially from top to bottom, and the substrate (1), the transition layer (2), and the base (5) are arranged concentrically. The molybdenum ring (4) is sleeved on the outer peripheral wall of the column formed by the substrate (1), the transition layer (2) and the base (5); The sidewall of the substrate (1) is provided with a radially extending insertion groove (6); The blocking ring (3) is inserted into the insertion slot (6), and the blocking ring (3) is arranged radially along the substrate (1).

2. The deposition stage as described in claim 1, characterized in that, The transition layer (2) is a metal thin film; the blocking ring (3) is an iron-based metal.

3. The deposition stage as described in claim 2, characterized in that, The transition layer (2) is any one or more of copper, silver, nickel, and titanium; the blocking ring (3) is any one or more of iron, cobalt, and nickel.

4. The deposition stage as described in claim 1 or 2, characterized in that, The substrate (1) is any one or both of molybdenum and tungsten; the substrate (1) has a diameter ≥ 6 inches, a thickness ≥ 7 mm, a roughness ≤ 10 nm, and a crystal orientation of [missing information]. <100> The thickness of the transition layer (2) is 0.02~0.1mm.

5. A method for preparing a large-size diamond film, characterized in that, The deposition stage is prepared using any one of claims 1 to 4, comprising the following steps: Step 1: Clean the substrate, and then place the substrate in a vacuum atmosphere to deposit a transition substrate film; Step 2: Place the substrate after the coating process into the MPCVD equipment for bias nucleation and growth processes in sequence; Step 3: Anneal the film grown in Step 2 to obtain the large-size diamond film.

6. The method for preparing a large-size diamond film as described in claim 5, characterized in that, In step 1, the coating process employs either electron beam evaporation or magnetron sputtering; the transition substrate film is any one or two of iridium, silicon, and titanium films; the coating thickness is 0.5~10μm, and the crystal orientation of the coating is... <100> .

7. The method for preparing a large-size diamond film as described in claim 5, characterized in that, During bias nucleation in step 2, the volume ratio of methane to hydrogen in the reaction chamber is (4%~6%):1, and the hydrogen flow rate is 1800~2500 sccm. During bias nucleation in step 2, the pressure in the reaction chamber is 20~25 kPa; During bias nucleation in step 2, the temperature inside the reaction chamber is 700~750℃; During bias nucleation in step 2, the bias voltage in the reaction chamber is (-200) ~ (-150) V; During bias nucleation in step 2, the bias duration in the reaction chamber is 1~3h.

8. The method for preparing a large-size diamond film as described in claim 5 or 7, characterized in that, During growth in step 2, a mixture of methane, hydrogen, and oxygen is continuously introduced into the reaction chamber. The volume ratio of methane to hydrogen in the reaction chamber is controlled to be (2.5%~4.5%):1, the hydrogen flow rate is 1800~4000 sccm, and the volume ratio of oxygen to hydrogen is (0.05%~0.15%):

1. In step 2, the growth power is 45~65kW; In step 2, the growth temperature is 800~950℃; In step 2, the working pressure of the reaction chamber is 21~26 kPa; In step 2, the growth time is 500~1000h.

9. The method for preparing a large-size diamond film as described in claim 5, characterized in that, In step 3, the methane concentration in the reaction system is controlled to be 0, and then the temperature is maintained at 1000~1200℃ for 1~2h. Then the temperature is lowered to 600~500℃ at 3~4℃ / min, and then lowered to room temperature at 1~2℃ / min. At this time, the diamond film automatically detaches from the substrate.

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