Method for roughening the surface of a three-dimensional precision-controlled area of a diamond window

Abstract

The application discloses a processing method for roughening the surface of a three-dimensional precision control area of a diamond window sheet, and comprises the following steps: S1, cutting and polishing a single crystal diamond material into an optical grade single crystal diamond window sheet; S2, cleaning the optical grade single crystal diamond window sheet; S3, protecting a non-metal area in the center of the optical grade single crystal diamond window sheet; S4, covering a film on an outer ring three-dimensional precision control area of the optical grade single crystal diamond window sheet, removing photoresist in the non-metal area, then placing the window sheet plated with the metal film in an atmosphere furnace for high-temperature etching, and finally removing residual metal or metal oxide on the surface to complete the roughening treatment of the three-dimensional precision control area; and S5, performing a metallization treatment on the outer ring three-dimensional precision control area to complete the covering of the metal plating layer. The method for roughening the surface of the three-dimensional precision control area of the diamond window sheet solves the problem of poor wettability between the diamond material and a heterogeneous material.

Description

Technical Field

[0001] This invention belongs to the field of vacuum electronic device technology and relates to a method for surface roughening of the three-dimensional precision control area of ​​a diamond window. Background Technology

[0002] The ever-increasing output power of vacuum electronic devices places higher demands on the materials used for microwave output windows. Sapphire, boron nitride, and beryllium oxide are the most commonly used energy transfer window materials in vacuum electronic devices. However, with the continuous increase in the output power of vacuum electronic devices such as traveling wave tubes, traditional microwave energy transfer windows cannot simultaneously meet the requirements of high power capacity and miniaturization. Therefore, there is an urgent need for new materials to upgrade and improve traditional microwave energy transfer windows. Diamond single crystals possess many excellent properties, such as extremely low dielectric loss, extremely high thermal conductivity, and the highest hardness and elastic modulus, and have been proven to be a near-perfect microwave window dielectric material. Diamond-based microwave output windows can achieve good matching across a wide bandwidth in the microwave, millimeter-wave, and even terahertz frequency bands, rapidly dissipating the heat absorbed during high-frequency microwave energy output, while resisting the high pressure difference across the window. Therefore, exploring wide-bandwidth, high-power, and small-volume diamond energy transfer windows is an important direction in the field of vacuum electronic devices.

[0003] However, due to the special crystal structure of diamond, its welding process has the following problems: (1) The chemical inertness of diamond results in a high interfacial energy between it and the solder metal. Whether in air or in a vacuum atmosphere, the surface of diamond hardly wets with ordinary brazing filler metal, making it difficult to react chemically with other metals and non-metals, let alone penetrate each other. Therefore, it is difficult to form a metallurgical bond during welding; (2) The welding temperature is limited. When it exceeds 1000 K, diamond will graphitize; (3) The thermal expansion coefficient of diamond is significantly different from that of other metals. The mismatch of thermodynamic properties on both sides of the interface leads to a large thermal stress after the welding temperature cools down, which reduces the reliability of the sealing part and may even cause cracking.

[0004] Therefore, surface metallization of diamond dielectric windows is fundamental to ensuring the hermeticity of the energy transmission window assembly. Currently, manual coating and magnetron sputtering techniques are mainly used to metallize the sides and edges of diamond single-crystal energy transmission windows. However, as research frequencies increase and the corresponding window sizes decrease, the uniformity and consistency of the coating cannot be guaranteed at the micrometer level during manual coating, leading to an increase in uncontrollable factors.

[0005] The nanoscale roughness and high transmittance of the energy transmission area of ​​the window are key parameters to ensure low transmission loss. However, during the magnetron sputtering metallization process, it is not conducive to improving the bonding strength between diamond and the coating metal, which may cause the metallization layer to peel or fall off, resulting in poor airtightness after the entire window is sealed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for surface roughening of the three-dimensional precision control area of ​​a diamond window, which improves the bonding force between single crystal diamond and the coating metal, meets the high airtightness requirements of the whole window sealing process, and solves the problem of poor wettability between diamond material and heterogeneous material.

[0007] The technical solution adopted in this invention is a method for surface roughening of the three-dimensional precision control area of ​​a diamond window, and the specific steps are as follows:

[0008] S1. Cut and polish the single-crystal diamond material into optical-grade single-crystal diamond windows;

[0009] S2. Clean the surface of the optical-grade single-crystal diamond window.

[0010] S3. Protect the non-metallic areas at the center of the upper and lower surfaces of the optical-grade single-crystal diamond window;

[0011] S4. A metal or metal oxide film is covered on the three-dimensional precision control area of ​​the outer ring of the optical-grade single crystal diamond window, and the photoresist in the non-metallic area of ​​the center of the window is removed. Then, the window with the metal film is placed in an atmosphere furnace for high-temperature etching. Finally, it is placed in dilute hydrochloric acid to remove the residual metal or metal oxide on the surface, thus completing the roughening treatment of the three-dimensional precision control area of ​​the outer ring.

[0012] S5. Metallize the outer ring three-dimensional precision control area after roughening the diamond window to complete the metal coating coverage.

[0013] The invention is further characterized by:

[0014] The single-crystal diamond material in S1 is an optical-grade single-crystal material, specifically HPHT single-crystal diamond, CVD single-crystal diamond, or natural diamond.

[0015] S1 optical-grade single-crystal diamond windows have a diameter of 1-15 mm, a thickness of 0.1-0.6 mm, a surface roughness Ra < 1 nm, a total thickness deviation (TTV) < 5 μm, and a thermal conductivity > 2000 W·m. -1 ·K -1 Infrared transmittance >70%;

[0016] The non-metallic area of ​​the optical-grade single-crystal diamond window is 0.6-12mm, and the width of the outer ring three-dimensional precision control area is 0.4-3mm.

[0017] The specific method for S2 is as follows:

[0018] Optical-grade single-crystal diamond windows are boiled in a mixed acid solution for 0.5-2 hours. The mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a ratio of 5-10:1. Subsequently, ultrasonic cleaning is performed. The cleaning solution is acetone, isopropanol, anhydrous ethanol, or deionized water.

[0019] The specific method of S3 is as follows: a photoresist layer with a diameter of 0.6-12mm is prepared in the central area of ​​the window using a photolithography mask or a stamping mask. The thickness of the photoresist layer is 100-500μm. The center point of the photoresist is ensured to coincide with the center point of the single crystal diamond wafer, and the three-dimensional precision control area around the window is ensured to be free of photoresist layer.

[0020] The specific method for S4 is as follows:

[0021] Metal or metal oxide thin films are deposited in a three-dimensional precision-controlled area using magnetron sputtering, electroplating, or deposition methods. The metal or metal oxide thin film material is Fe, Ni, Co, Fe2O3, MnO2, or NiO. The process parameters are: background vacuum level 6-9 x 10. -4 Pa, working pressure 1.5-2.0 Pa, RF power 250-400 W, sample distance from target 8-10 mm, sputtering time 2-5 min, and film thickness of coating 50-500 nm;

[0022] After coating, the sample is placed in a photoresist remover or acetone to remove the photoresist in the central area of ​​the single-crystal diamond wafer, and the metal or metal oxide film on its surface is also removed. Then, the window with the metal or metal oxide film is placed in a vacuum furnace, and 50-100 sccm of hydrogen gas is introduced. The temperature is increased at a rate of 3-8℃ / min until the temperature reaches 600-900℃, and the holding time is 10-60min. Finally, the single-crystal diamond window is placed in dilute hydrochloric acid and heated to 80℃ to remove the residual metal or metal oxide on the surface. Then, it is ultrasonically cleaned in acetone or deionized water for 15min each to complete the roughening treatment of the three-dimensional precision control area of ​​the outer ring of the optical-grade single-crystal diamond window.

[0023] The surface roughness Ra of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window in S4 after roughening treatment is 0.1-0.8 μm.

[0024] In S5, a metal coating is applied to the outer ring three-dimensional precision control area by magnetron sputtering, electroplating or ion implantation. The metallization coating is applied in batches and multiple times. The coating metal includes three or more of Ti, Cu, Ni, Wu, Mo, Cr, Fe, Si or Pt.

[0025] The process parameters are: cavity vacuum degree 1-5 x 10 -3Pa, working pressure is 0.5-3Pa, radio frequency power is 800-1200W, sample rotates around the target material, distance from the target material is 5-10cm, metallization coating thickness is 2-10um, and coating time is 10-60min.

[0026] The beneficial effects of this invention are:

[0027] (1) The optical grade single crystal diamond used in the three-dimensional precision control area surface roughening treatment method of the diamond window of the present invention has the advantages of low dielectric constant, high optical transmittance and high thermal conductivity. It is a key medium for realizing high frequency, high power and lightweight vacuum electronic devices. At the same time, the energy transmission area is an ultra-smooth surface with high overall thickness consistency and low transmission loss.

[0028] (2) The surface roughening method of the three-dimensional precision control area of ​​the diamond window of the present invention roughens the outer ring of the single crystal diamond window before metallizing it. This reduces the interfacial energy between the single crystal diamond and the heterogeneous material, enhances the bonding strength between the metal coating and the diamond window, and ensures the vacuum degree after the energy transmission window is welded. At the same time, the nanoscale roughness and high transmittance of the energy transmission area in the center of the diamond window are controlled to ensure low transmission loss of the energy transmission window. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the surface roughening treatment of the three-dimensional precision control area of ​​the outer ring of the optical-grade diamond single crystal window of the present invention;

[0030] Figure 2 This is a structural diagram of the metallized coating in the outer ring three-dimensional precision control area of ​​Embodiment 1 of the present invention without roughening treatment;

[0031] Figure 3 This is a diagram of the metallized coating structure of the outer ring three-dimensional precision control area after roughening treatment in Embodiment 1 of the present invention. Detailed Implementation

[0032] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0033] The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to the present invention comprises the following steps:

[0034] S1. Cut and polish the single-crystal diamond material into optical-grade single-crystal diamond windows. The size is determined according to the transmission band of different applications. The single-crystal diamond material is optical-grade single-crystal material, specifically HPHT single-crystal diamond, CVD single-crystal diamond or natural diamond. It has the advantages of low dielectric constant, high optical transmittance and high thermal conductivity. It is a key medium for realizing high frequency, high power and lightweight vacuum electronic devices.

[0035] The polished optical-grade single-crystal diamond windows have a diameter of 1-15 mm, a thickness of 0.1-0.6 mm, a surface roughness Ra < 1 nm, a total thickness deviation (TTV) < 5 μm, and a thermal conductivity > 2000 W·m. -1 ·K -1 Infrared transmittance >70%; the non-metallic area of ​​the optical-grade single-crystal diamond window is 0.6-12mm, and the width of the outer ring three-dimensional precision control area is 0.4-3mm.

[0036] S2. Surface cleaning of the optical-grade single-crystal diamond window is performed using the following method:

[0037] Optical-grade single-crystal diamond windows are boiled in a mixed acid solution for 0.5-2 hours. The mixed acid solution is prepared by concentrated sulfuric acid and concentrated nitric acid in a ratio of 5-10:1. After that, ultrasonic cleaning is performed. The cleaning solution is acetone, isopropanol, anhydrous ethanol or deionized water, etc.

[0038] S3. Protect the non-metallic areas at the center of the upper and lower surfaces of the optical-grade single-crystal diamond window. The specific method is as follows: use a photolithography mask or a stamping mask to prepare a photoresist layer with a diameter of 0.6-12mm in the center area of ​​the window. The thickness of the photoresist layer is 100-500μm. Ensure that the center point of the photoresist coincides with the center point of the single-crystal diamond wafer, and ensure that there is no photoresist layer in the three-dimensional precision control area around the outer ring of the single-crystal diamond window.

[0039] S4. A metal or metal oxide film is deposited on the outer ring three-dimensional precision control region (metallized region) of the optical-grade single-crystal diamond window, and the photoresist in the non-metallic region of the center of the single-crystal diamond window is removed. The window with the metal film is then placed in an atmosphere furnace for high-temperature etching. Finally, it is placed in dilute hydrochloric acid to remove residual metal or metal oxide from the surface, completing the roughening treatment of the outer ring three-dimensional precision control region. The surface roughness Ra of the outer ring three-dimensional precision control region of the optical-grade single-crystal diamond window after roughening treatment is 0.1-0.8 μm. Figure 1 As shown, the specific method is as follows:

[0040] On a window with a uniform adhesive layer in the central non-metallic area, one or more layers of metal or metal oxide thin films are deposited using magnetron sputtering, electroplating, or deposition. The metal or metal oxide thin film material is Fe, Ni, Co, Fe2O3, MnO2, or NiO, etc. Specific process parameters are: background vacuum degree of 6-9 x 10. -4 Pa, working pressure is 1.5-2.0 Pa, radio frequency power is 250-400 W, sample distance from target is 8-10 mm, sputtering time is 2-5 min, and film thickness is 50-500 nm;

[0041] After coating, the sample is placed in a resist remover or acetone solution to remove the photoresist in the central area of ​​the single-crystal diamond wafer, thereby removing the metal or metal oxide film on its surface. The window coated with the metal or metal oxide film is then placed in a vacuum furnace, and hydrogen gas is introduced at 50-100 sccm. The temperature is increased at a rate of 3-8℃ / min until it reaches 600-900℃, and held at that temperature for 10-60 minutes. Finally, the single-crystal diamond window is placed in dilute hydrochloric acid and heated to 80℃ to remove any remaining metal or metal oxide on the surface. It is then ultrasonically cleaned for 15 minutes each in acetone and deionized water, thus achieving roughening treatment of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window.

[0042] S5. Metallize the three-dimensional precision control area after roughening the diamond window to complete the metal coating coverage.

[0043] Specifically, magnetron sputtering, electroplating, or ion implantation are used to coat the roughened outer ring of the window with a three-dimensional precision-controlled metal coating. The metallization coating thickness is 2-10 μm, and the metallization coating is a multi-layer composite structure, applied in batches and multiple times. The coating metal includes three or more of Ti, Cu, Ni, Wu, Mo, Cr, Fe, Si, or Pt. The specific process involves a cavity vacuum degree of 1-5 x 10. -3 Pa, working pressure 0.5-3Pa, RF power 800-1200W, sample rotates around the target, distance from the target 5-10cm, coating thickness 2-10um, coating time 10-60min.

[0044] This invention employs a roughening treatment in specific areas to enhance the adhesion between the metal coating and the diamond sheet, while simultaneously ensuring that the central area retains its mirror-like finish. Furthermore, the selected material is single-crystal diamond, which offers superior material properties and processing quality.

[0045] Example 1

[0046] The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to the present invention comprises the following steps:

[0047] S1. Cut and polish HPHT single-crystal diamond into circular wafers with a diameter of 3mm and a thickness of 0.2mm, ensuring that the surface roughness Ra < 1nm, the total thickness deviation TTV < 3um, and the thermal conductivity > 2000W·m. -1 ·K -1 Infrared transmittance >70%.

[0048] S2. The optical-grade single-crystal diamond window is boiled in a mixed acid solution for 0.5 hours. The mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a ratio of 5:1. Then, it is ultrasonically cleaned in an acetone solution.

[0049] S3. A photoresist layer with a diameter of 0.6 mm and a thickness of 200 μm is prepared in the central area of ​​the window using a photolithography mask to ensure that there is no photoresist layer in the three-dimensional precision control area around the single crystal diamond window.

[0050] S4. Two Fe metal films are coated onto the window with a uniform adhesive layer in the central non-metallic region using magnetron sputtering. The process parameters are: background vacuum of 6 x 10. -4 Pa, working pressure is 1.8 Pa, radio frequency power is 300 W, sample distance from target is 8 mm, sputtering time is 2 min, and film thickness is 300 nm;

[0051] After coating, the sample was placed in a photoresist remover solution to remove the photoresist in the central area of ​​the single-crystal diamond wafer, thereby removing the Fe metal film on its surface. The window was then placed in a vacuum furnace, and hydrogen gas was introduced at 50 sccm. The temperature was increased at a rate of 8℃ / min until it reached 900℃, and held at that temperature for 10 min. Finally, the single-crystal diamond window was placed in dilute hydrochloric acid and heated to 80℃ to remove residual metal from the surface. It was then ultrasonically cleaned for 15 min each in acetone and deionized water to complete the roughening treatment of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window.

[0052] Unroughened metallized coatings, such as Figure 2 As shown, the roughened metallized coating is as follows Figure 3 As shown.

[0053] S5. A metal coating is applied to the three-dimensional precision-controlled area of ​​the outer ring of the roughened window using magnetron sputtering. Specifically, Ti is first coated onto the diamond, then Ni is coated onto the Ti, and finally Mo is coated onto the Ni. The process parameters are: cavity vacuum degree 1 x 10. -3 Pa, working pressure 2Pa, RF power 800W, sample rotates around the target, distance from the target 8cm, coating thickness 2µm, coating time 30min.

[0054] Example 2

[0055] S1. Cut and polish CVD single-crystal diamond into circular wafers with a diameter of 15mm and a thickness of 0.6mm, ensuring that the surface roughness Ra < 1nm, the total thickness deviation TTV < 3um, and the thermal conductivity > 2000W·m. -1 ·K -1 Infrared transmittance >70%.

[0056] S2. The optical-grade single-crystal diamond window is boiled in a mixed acid solution for 2 hours. The mixed acid solution is prepared by a ratio of concentrated sulfuric acid and concentrated nitric acid of 10:1. Then, it is ultrasonically cleaned in an isopropanol solution.

[0057] S3. A photoresist layer with a diameter of 12mm and a thickness of 500μm is prepared in the center area of ​​the window using a stamping mask method to ensure that there is no photoresist layer in the three-dimensional precision control area around the single crystal diamond window.

[0058] S4. Two Ni metal films are electroplated onto the window where a uniform adhesive layer is left in the central non-metallic area. The process parameters are: background vacuum degree is 9 x 10. -4 Pa, working pressure is 2.0 Pa, RF power is 400 W, sample distance from target is 10 mm, sputtering time is 5 min, and film thickness is 500 nm;

[0059] After coating, the sample was placed in acetone solution to remove the photoresist in the central area of ​​the single-crystal diamond wafer, thereby removing the Ni metal film on its surface. The window was then placed in a vacuum furnace, and 100 sccm of hydrogen gas was introduced. The temperature was increased at a rate of 3℃ / min until it reached 600℃, and held at that temperature for 60 min. Finally, the single-crystal diamond window was placed in dilute hydrochloric acid and heated to 80℃ to remove residual metal from the surface. It was then ultrasonically cleaned for 15 min each in acetone and deionized water to complete the roughening treatment of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window.

[0060] S5. An electroplating process is used to coat the roughened outer ring three-dimensional precision control area of ​​the window with a metal coating. Specifically, Ti is first coated onto the diamond, then Cu is coated onto the Ti, and finally Wu is coated onto the Cu. The process parameters are: cavity vacuum degree 5 x 10. -3 Pa, working pressure 3Pa, RF power 1200W, sample rotates around the target, distance from the target 10cm, coating thickness 10um, coating time 60min.

[0061] Example 3

[0062] S1. Cut and polish natural diamonds into round slices with a diameter of 0.1 mm and a thickness of 1 mm, ensuring a surface roughness Ra < 1 nm, a total thickness deviation TTV < 3 μm, and a thermal conductivity > 2000 W·m. -1 ·K -1 Infrared transmittance >70%.

[0063] S2. The optical-grade single-crystal diamond window is boiled in a mixed acid solution for 1 hour. The mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a ratio of 8:1. Then, it is ultrasonically cleaned in an anhydrous ethanol solution.

[0064] S3. A photoresist layer with a diameter of 1 mm and a thickness of 100 μm is prepared in the central area of ​​the window using a stamping mask method to ensure that there is no photoresist layer in the three-dimensional precision control area around the single crystal diamond window.

[0065] S4. Two layers of Fe2O3 metal oxide film are deposited on the window with a uniform adhesive layer in the central non-metallic region using a deposition method. The process parameters are: background vacuum of 7 x 10. -4 Pa, working pressure is 1.5 Pa, RF power is 250 W, sample distance from target is 9 mm, sputtering time is 4 min, and film thickness is 50 nm.

[0066] After coating, the sample is placed in acetone solution to remove the photoresist in the central area of ​​the single-crystal diamond wafer, thereby removing the metal or metal oxide film on its surface. The window is then placed in a vacuum furnace, and hydrogen gas is introduced at 80 sccm. The temperature is increased at a rate of 5℃ / min until it reaches 700℃, and held at that temperature for 30 min. Finally, the single-crystal diamond window is placed in dilute hydrochloric acid and heated to 80℃ to remove residual metal oxides from the surface. It is then ultrasonically cleaned for 15 min each in acetone and deionized water to complete the roughening treatment of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window.

[0067] S5. An ion implantation method is used to coat the roughened outer ring three-dimensional precision control area of ​​the window with a metal coating. Specifically, Cu is first coated onto the diamond, then Wu is coated onto the Cu, then Cr is coated onto the Wu, and finally Pt is coated onto the Cr. The process parameters are: cavity vacuum degree 3 x 10. -3 Pa, working pressure 0.5Pa, RF power 1000W, sample rotates around the target, distance from the target 5cm, coating thickness 5µm, coating time 10min.

[0068] Example 4

[0069] S1. Cut and polish HPHT single-crystal diamond into circular wafers with a diameter of 8mm and a thickness of 0.3mm, ensuring that the surface roughness Ra < 1nm, the total thickness deviation TTV < 3um, and the thermal conductivity > 2000W·m. -1 ·K -1 Infrared transmittance >70%.

[0070] S2. The optical-grade single-crystal diamond window is boiled in a mixed acid solution for 1.5 hours. The mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a ratio of 7:1. Then, it is ultrasonically cleaned in deionized water.

[0071] S3. A photoresist layer with a diameter of 5mm and a thickness of 300μm is prepared in the central area of ​​the window using a photolithography mask to ensure that there is no photoresist layer in the three-dimensional precision control area around the single crystal diamond window.

[0072] S4. Two layers of MnO2 metal oxide film are electroplated onto the window with a uniform adhesive layer in the central non-metallic area. The process parameters are: background vacuum degree of 8 × 10. -4 Pa, working pressure is 1.8 Pa, RF power is 350 W, sample distance from target is 8 mm, sputtering time is 3 min, and film thickness is 300 nm;

[0073] After coating, the sample was placed in acetone solution to remove the photoresist in the central area of ​​the single-crystal diamond wafer, thus removing the metal oxide film on its surface. The window was then placed in a vacuum furnace, and hydrogen gas was introduced at 50 sccm. The temperature was increased at a rate of 8℃ / min until it reached 800℃, and held at that temperature for 25 min. Finally, the single-crystal diamond window was placed in dilute hydrochloric acid and heated to 80℃ to remove any residual metal or metal oxides from the surface. It was then ultrasonically cleaned for 15 min each in acetone and deionized water to complete the roughening treatment of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window.

[0074] S5. An ion implantation method is used to coat the roughened outer ring three-dimensional precision control area of ​​the window with a metal coating. Specifically, Ti is first coated onto the diamond, then Wu is coated onto the Ti, then Mo is coated onto the Wu, and finally Si is coated onto the Mo. The process parameters are: cavity vacuum degree 1 x 10. -3 Pa, working pressure 2Pa, RF power 800W, sample rotates around the target, distance from the target 8cm, coating thickness 2µm, coating time 30min.

[0075] Example 5

[0076] The methods and steps are the same as in Example 1, except that: the single crystal diamond material used in S1 is CVD single crystal diamond; and a photoresist layer is prepared in the central region of the window by means of a stamping mask in S3.

[0077] The metal coating structure in S5 is as follows: Wu is first coated on diamond, then Fe is coated on Wu, then Pt is coated on Fe, and finally Si is coated on Pt.

[0078] The remaining steps and parameters are the same as in Example 1.

[0079] Example 6

[0080] The method and steps are the same as in Example 2. The difference between Example 2 and Example 2 is that the single crystal diamond material used in S1 is natural diamond; in S4, a NiO metal oxide film is coated on the window using magnetron sputtering. The remaining steps and parameters are the same as in Example 2.

Claims

1. A method for surface roughening of the three-dimensional precision control area of ​​a diamond window, characterized in that, The specific steps are as follows: S1. Cut and polish the single-crystal diamond material into optical-grade single-crystal diamond windows; S2. Clean the surface of the optical-grade single-crystal diamond window. S3. Protect the non-metallic areas at the center of the upper and lower surfaces of the optical-grade single-crystal diamond window; S4. A metal or metal oxide film is covered on the three-dimensional precision control area of ​​the outer ring of the optical-grade single crystal diamond window, and the photoresist in the non-metallic area of ​​the center of the window is removed. Then, the window with the metal or metal oxide film is placed in an atmosphere furnace for high-temperature etching. Finally, it is placed in dilute hydrochloric acid to remove the residual metal or metal oxide on the surface, thus completing the roughening treatment of the three-dimensional precision control area of ​​the outer ring. The metal or metal oxide thin film is made of Fe, Ni, Co, Fe2O3, MnO2 or NiO; The thickness of the metal or metal oxide film is 50-500 nm; S5. Metallize the outer ring three-dimensional precision control area after roughening the diamond window to complete the metal coating coverage.

2. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 1, characterized in that, The single-crystal diamond material in S1 is an optical-grade single-crystal material, specifically HPHT single-crystal diamond, CVD single-crystal diamond, or natural diamond.

3. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 2, characterized in that, The optical-grade single-crystal diamond window in S1 has a diameter of 1-15 mm, a thickness of 0.1-0.6 mm, a surface roughness Ra < 1 nm, a total thickness deviation TTV < 5 μm, and a thermal conductivity > 2000 W·m. -1 ·K -1 Infrared transmittance >70%; The width of the three-dimensional precision control area of ​​the outer ring of the optical-grade single-crystal diamond window is 0.4-3mm.

4. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 1, characterized in that, The specific method of S2 is as follows: Optical-grade single-crystal diamond windows are boiled in a mixed acid solution for 0.5-2 hours. The mixed acid solution is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a ratio of 5-10:

1. Subsequently, ultrasonic cleaning is performed. The cleaning solution is acetone, isopropanol, anhydrous ethanol, or deionized water.

5. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 1, characterized in that, The specific method of S3 is as follows: a photoresist layer with a diameter of 0.6-12mm is prepared in the central area of ​​the window using a photolithography mask or a stamping mask. The thickness of the photoresist layer is 100-500μm, ensuring that the center point of the photoresist coincides with the center point of the single crystal diamond wafer, and ensuring that there is no photoresist layer in the three-dimensional precision control area around the window.

6. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 1, characterized in that, The specific method of S4 is as follows: Metal or metal oxide thin films are deposited in a three-dimensional precision-controlled area using magnetron sputtering or electroplating methods. The process parameters are: base vacuum degree 6-9 × 10⁻⁶. -4 Pa, working pressure 1.5-2.0 Pa, RF power 250-400 W, sample distance from target 8-10 mm, sputtering time 2-5 min; After coating, the sample is placed in a resist remover to remove the photoresist in the central area of ​​the single-crystal diamond wafer. Then, the window coated with a metal or metal oxide film is placed in a vacuum furnace, and hydrogen gas is introduced at a rate of 50-100 sccm. The temperature is increased at a rate of 3-8℃ / min until it reaches 600-900℃. The holding time is 10-60 min. Finally, the single-crystal diamond window is placed in dilute hydrochloric acid and heated to 80℃ to remove the residual metal or metal oxide on the surface. Then, it is ultrasonically cleaned in acetone or deionized water for 15 min each to complete the roughening treatment of the three-dimensional precision control area of ​​the outer ring of the optical-grade single-crystal diamond window.

7. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 1, characterized in that, The surface roughness Ra of the outer ring three-dimensional precision control area of ​​the optical-grade single-crystal diamond window in S4 after roughening treatment is 0.1-0.8 μm.

8. The method for surface roughening of the three-dimensional precision control area of ​​a diamond window according to claim 1, characterized in that, In S5, a metal coating is applied to the outer ring three-dimensional precision control area by magnetron sputtering, electroplating, or ion implantation. The metal coating is applied in batches and multiple times, and the coating metal includes three or more of Ti, Cu, Ni, Mo, Cr, Fe, Si, or Pt. The process parameters are: cavity vacuum degree 1-5 × 10 -3 Pa, working pressure is 0.5-3Pa, radio frequency power is 800-1200W, sample rotates around the target material, distance from the target material is 5-10cm, metallization coating thickness is 2-10um, and coating time is 10-60min.

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