Surface gradient metallized heat sink diamond and preparation method thereof

Abstract

The invention mainly provides a surface gradient metallization heat sink diamond and a preparation method thereof, and the surface gradient metallization heat sink diamond comprises a diamond substrate, a Zr transition layer formed on the diamond surface through ion implantation, a Zr bonding layer formed on the Zr transition layer through high-power pulse magnetron sputtering (HiPMS), and a Ni welding barrier layer formed on the Zr bonding layer through high-power pulse magnetron sputtering, and the Au welding layer is formed on the Ni welding barrier layer through high-power pulse magnetron sputtering. The preparation method comprises the following steps: pre-treating a diamond substrate, performing ion implantation of Zr, performing bias self-cleaning, depositing Zr, Ni and Au in sequence by high-power pulse magnetron sputtering, and finally putting the treated diamond substrate into a vacuum tube furnace for heat preservation. The method has the beneficial effects that multiple performance breakthrough of diamond surface metallization is achieved, the problem of heavy metal pollution of the chemical plating process and the problem of wastewater discharge of a traditional process are reduced, the thickness of a plating layer can be accurately controlled, and the manufacturing level of the method is remarkably superior to that of the traditional process.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface modification of high thermal conductivity materials and heat dissipation of electronic devices, and specifically relates to a diamond heat sink material with a surface gradient metallization structure and a preparation method thereof, which is particularly suitable for the efficient heat dissipation requirements in high-power semiconductor device packaging. Background Art

[0002] With the continuous development of semiconductor technology, the thermal management problem of semiconductor devices has become increasingly prominent. Especially under extreme conditions such as high power, high frequency, and high temperature, the heat dissipation problem of semiconductor devices has become a key factor restricting their performance and reliability. As a material with excellent properties such as high thermal conductivity, high breakdown electric field, and high carrier mobility, diamond has shown great application potential in the thermal management of semiconductor devices. However, when diamond is used as a transition heat sink, it is difficult to achieve a good interface bonding with the secondary heat sink (copper) through wetting due to its chemical inertness, low thermal expansion, and difficulty in wetting and welding with metals. As a result, the assembly and application of diamond with other devices and solders are greatly restricted; in addition, metals rely on the thermal motion of free electrons to transfer heat, while diamond is a sp bond formed by carbon atoms and adjacent carbon atoms. 3 Hybrid orbitals have no free electrons and rely on lattice vibrations to transfer heat. The heat transfer methods at the interface between the two are different, which will produce a large interfacial thermal resistance, making it impossible to fully utilize the thermal conductivity potential of diamond.

[0003] Current technology mainly uses vacuum evaporation coating and chemical plating to achieve diamond metallization. However, vacuum evaporation coating technology faces the problem of difficult to accurately control the thickness of the coating, and during the welding stage, the metal layer on the surface of the diamond is easily oxidized, which weakens the welding bond with the device and increases the risk of falling off. In contrast, although chemical plating technology is feasible, it relies on chemical reagents and is accompanied by a large amount of wastewater discharge, which has significant environmental pollution problems. Therefore, there is an urgent need to develop a new diamond surface metallization method to optimize the interface bonding between diamond and metal, reduce the interface thermal resistance, and significantly improve the welding performance of the two. Summary of the invention

[0004] To solve the above problems, the present invention provides a surface gradient metallized heat sink diamond, comprising: a diamond substrate; a Zr transition layer formed on the diamond surface; a Zr bonding layer formed on the Zr transition layer; a Ni welding barrier layer formed on the Zr bonding layer; and an Au welding layer formed on the Ni welding barrier layer.

[0005] Furthermore, the total thickness of the Zr bonding layer is 80-100 nm; the total thickness of the Ni solder barrier layer is 300-450 nm; and the total thickness of the Au solder layer is 150-200 nm.

[0006] Furthermore, the Zr transition layer is formed by ion implantation, and the Zr bonding layer, the Ni welding barrier layer and the Au welding layer are formed by high-power pulsed magnetron sputtering.

[0007] In addition, the present invention also provides a method for preparing a heat sink diamond with a surface gradient metallization, comprising the following steps: Step 1: Substrate pretreatment: ultrasonic acetone cleaning, ultrasonic ethanol cleaning, ultrasonic deionized water rinsing, dehydration and drying of the CVD diamond in sequence; Step 2: ion implantation of Zr; placing the diamond treated in step 1 in an ion implantation device, and performing ion implantation using a Zr target to form a Zr transition layer; Step 3: Depositing a Zr transition layer; adjusting the argon flux and the working gas pressure in the magnetron sputtering vacuum chamber and heating it, turning on the magnetron Zr target source and the bias power supply, and depositing a Zr bonding layer; Step 4: Depositing a Ni welding barrier layer; switching the magnetron sputtering power supply, target material and working gas pressure, depositing a second layer of metal Ni as a solder mask metal on the diamond substrate of the Zr transition layer to form a Ni welding barrier layer; Step 5: depositing an Au welding layer; switching the magnetron sputtering power supply, target material and working gas pressure, depositing a third layer of metal Au as a welding layer metal on the Ni welding barrier layer to form an Au welding layer; Step 6: After the Au welding layer is deposited, turn off the power supply and the argon gas, wait until the temperature of the magnetron sputtering vacuum chamber drops below 100°C, and then turn off the vacuum system; Step 7: Place the diamond substrate after step 6 into a vacuum tube furnace and heat it to 500-800°C for insulation.

[0008] Furthermore, in step 1, the three washing times of ultrasonic acetone cleaning, ultrasonic ethanol, and ultrasonic deionized water rinsing are not less than 15 minutes respectively, and each washing is repeated at least 2-4 times; after step 2, step 2.1 is further included: bias self-cleaning; the diamond substrate treated in step 2 is placed in a magnetron sputtering vacuum chamber, the background vacuum degree of the magnetron sputtering vacuum chamber is adjusted, and argon gas is introduced to realize bias self-cleaning of the surface of the diamond substrate treated in step 2.

[0009] Furthermore, in step 2, the background vacuum of the vacuum chamber of the ion implantation equipment is less than 1×10 -4 Pa, heating temperature is 300~500℃. Adjust the ion implantation energy to 1~3MeV, adjust the ion beam current to 1~100mA, and the ion implantation metering to 1.0×10 16 ~1.0×10 18 atoms / cm 2 .

[0010] Furthermore, in step 3, the background vacuum degree of the vacuum chamber of the magnetron sputtering equipment is less than 7×10 -4 Pa, working gas pressure is not less than 10Pa, bias power supply is 200~500V.

[0011] Furthermore, in step 4, the working gas pressure of the vacuum chamber of the magnetron sputtering equipment is 0.4~1Pa, and the heating temperature is 100~260℃; the Zr target power supply is a HiPIMS power supply, and the constant power mode is set to 200~400W, the pulse width is 60~100μs, and the pulse frequency is 400~600Hz; the bias power supply is a DC power supply, and the bias size is set to 80~160V; the thickness of the Zr bonding layer is 80~100nm.

[0012] Furthermore, in step 5, the Ni target uses a HiPIMS power supply, sets the constant power mode to 300~500W, the pulse width to 80~120μs, and the pulse frequency to 400~600Hz; the bias power supply is a DC power supply, the bias size is set to 100~180V, and the working gas pressure is 0.6~1Pa; the total thickness of the Ni welding barrier layer is 300~450nm.

[0013] Furthermore, in step six, the Au target uses a HiPIMS power supply, and the constant power mode is set to 150~250W, the pulse width is 60~100μs, and the pulse frequency is 300~600Hz; the bias power supply is a DC power supply, the bias size is set to 80~160V, and the working gas pressure is 0.4~1Pa; the total thickness of the Au coating is 150~200nm.

[0014] Therefore, the present invention achieves multiple performance breakthroughs in diamond surface metallization by matching the gradient metallization structure design with precisely controllable process parameters. First, a gradient interface is formed by the Zr transition layer formed by ion implantation and the Zr bonding layer deposited by subsequent HiPIMS. The in-situ generation of ZrC compounds after Zr injection on the diamond surface significantly improves the interface bonding strength, while alleviating the mismatch in thermal expansion coefficients between diamond and the metal layer. Secondly, the Ni welding barrier layer is formed by high-power pulsed magnetron sputtering to form a dense barrier structure, which effectively inhibits metal diffusion and oxidation during high-temperature welding. Finally, the Au welding layer is prepared by HiPIMS to improve the welding bonding strength. The overall process completely avoids the heavy metal pollution problem of the chemical plating process through a full physical vapor deposition path, effectively reduces the amount of wastewater discharged, and the thickness of each coating layer can be precisely controlled, which is significantly better than the traditional processing level. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the preparation process of Example 1 of the present invention.

[0016] Figure 2This is a diagram of the ion implantation SRIM simulation results of Example 1 of the present invention.

[0017] Figure 3 The figure shows the morphology of the Au layer on the surface of the CVD diamond after surface metallization in Example 1 of the present invention. DETAILED DESCRIPTION

[0018] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, reference may be made to the accompanying drawings and embodiments to further illustrate the technical solutions of the present invention. It should be understood that the embodiments described herein are only used to explain the technical solutions or principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0019] The present invention discloses a heat sink diamond with surface gradient metallization, comprising a diamond substrate, a Zr transition layer formed on the diamond surface by ion implantation, a Zr bonding layer formed on the Zr transition layer by high power pulsed magnetron sputtering (HiPMS), a Ni welding barrier layer formed on the Zr bonding layer by high power pulsed magnetron sputtering, and an Au welding layer formed on the Ni welding barrier layer by high power pulsed magnetron sputtering. The Zr transition layer is mainly ZrC, the total thickness of the Zr bonding layer is 80-100 nm; the total thickness of the Ni welding barrier layer is 300-450 nm; and the total thickness of the Au welding layer is 150-200 nm.

[0020] The following is a specific embodiment of a method for preparing a surface gradient metallized heat sink diamond proposed by the present invention: Example

[0021] This embodiment includes the following steps: Step 1: Clean the CVD diamond with ultrasonic acetone, ultrasonic ethanol, and ultrasonic deionized water for 15 minutes in sequence, repeat the ultrasonic cleaning twice, and then rinse, dehydrate and dry.

[0022] Step 2: Place the diamond substrate treated in step 1 in the vacuum chamber of the ion implantation equipment, install the Zr target, and adjust the background vacuum degree of the vacuum chamber of the ion implantation equipment to 7×10 -5 Pa and heated to 400 °C, turned on the ion implantation source, adjusted the ion implantation energy to 3 MeV, the ion beam intensity to 50 mA, and the ion implantation metering to 1.0 × 10 16 atoms / cm 2 , open the baffle, when the ion implantation dosage reaches the preset value, close the baffle, turn off the ion source, wait until the temperature of the workpiece drops below 100° C., turn off the vacuum system, and form a Zr transition layer.

[0023] Step 3: Place the diamond substrate processed in step 2 into a magnetron sputtering vacuum chamber, and adjust the background vacuum of the magnetron sputtering vacuum chamber to 1×10 -4Adjust the argon flow rate to a working pressure of 10Pa, adjust the bias power supply voltage to 300V, and implement bias self-cleaning on the surface of the diamond substrate. After completion, turn off the bias power supply and gas.

[0024] Step 4: Adjust the argon flow rate to a working pressure of 0.5 Pa and heat to 180°C. Turn on the magnetron Zr target source, set the constant power mode to 300W, set the pulse width to 60μs, set the pulse frequency to 600Hz, and adjust the bias power supply voltage to 100V to form a Zr bonding layer with a total thickness of 100nm.

[0025] Step 5: Adjust the argon flow rate to the working gas pressure of 0.7Pa, and then use HiPIMS technology to deposit a second layer of metal Ni on the diamond substrate with Zr coating, set the power mode to 400W, set the pulse width to 80μs, set the pulse frequency to 600Hz, and adjust the bias power supply voltage to 150V to form a Ni welding barrier layer. The total thickness of the Ni welding barrier layer is 400nm.

[0026] Step 6: Adjust the argon gas flow rate to the working gas pressure of 0.5Pa, and then use HiPIMS technology to deposit the third metal Au layer on the diamond substrate with the Ni welding barrier layer deposited. Set the power mode to 200W, set the pulse width to 60μs and keep it unchanged. Set the pulse frequency to 600Hz and adjust the bias power supply voltage to 100V to form an Au welding layer. The total thickness of the Au welding layer is 180nm.

[0027] Step 7: After the third metal layer is deposited, turn off all power supplies and argon gas, wait until the temperature of the magnetron sputtering vacuum chamber drops below 100° C., and then turn off the vacuum system.

[0028] Step 8: Place the diamond substrate after step 7 in a vacuum tube furnace, gradually heat it to 600°C at 4°C / min and keep it for 12 minutes. When the furnace temperature cools to room temperature, open the vacuum tube furnace, take out the CVD diamond, dry it, and store it in a vacuum bag. Example

[0029] This embodiment includes the following steps: Step 1: Clean the CVD diamond with ultrasonic acetone, ultrasonic ethanol, and ultrasonic deionized water for 15 minutes in sequence, repeat the ultrasonic cleaning twice, and then rinse, dehydrate and dry.

[0030] Step 2: Place the diamond substrate processed in step 1 in the vacuum chamber of the ion implantation equipment, install the Zr target, adjust the background vacuum degree of the vacuum chamber of the ion implantation equipment to 7×10-5Pa and heat it to 400°C, turn on the ion implantation source, adjust the ion implantation energy to 3Mev, the ion beam intensity to 50mA, the ion implantation metering to 1.0×1016 atoms / cm2, open the baffle, and when the ion implantation metering reaches the preset value, close the baffle, turn off the ion source, wait until the temperature of the workpiece drops below 100°C, turn off the vacuum system, and form a Zr transition layer.

[0031] Step 3: Place the diamond substrate processed in step 2 into a magnetron sputtering vacuum chamber, and adjust the background vacuum degree of the magnetron sputtering vacuum chamber to 1×10- 4 Adjust the argon flow rate to a working pressure of 10Pa, adjust the bias power supply voltage to 300V, and implement bias self-cleaning on the surface of the diamond substrate. After completion, turn off the bias power supply and gas.

[0032] Step 4: Adjust the argon flow rate to a working pressure of 0.4 Pa and heat to 200° C. Turn on the magnetron Zr target source, set the constant power mode to 400 W, set the pulse width to 60 μs, set the pulse frequency to 600 Hz, and adjust the bias power supply voltage to 120 V to form a Zr bonding layer with a total thickness of 80 nm.

[0033] Step 5: Adjust the argon flow rate to the working gas pressure of 0.7Pa, and then use HiPIMS technology to deposit the second layer of metal Ni on the diamond substrate with the Zr bonding layer deposited. Set the power mode to 500W, set the pulse width to 80μs and keep it unchanged. Set the pulse frequency to 600Hz and adjust the bias power supply voltage to 120V to form a Ni welding barrier layer. The total thickness of the Ni welding barrier layer is 300nm.

[0034] Step 6: Adjust the argon gas flow rate to the working gas pressure of 0.4Pa, and then use HiPIMS technology to deposit the third metal Au layer on the diamond substrate with a Ni welding barrier layer deposited on it. Set the power mode to 150W, set the pulse width to 60μs and keep it unchanged. Set the pulse frequency to 600Hz and adjust the bias power supply voltage to 120V to form an Au welding layer. The total thickness of the Au welding layer is 150nm.

[0035] Step 7: After depositing the third metal layer, turn off all power supplies and argon gas, wait until the temperature of the magnetron sputtering vacuum chamber drops below 100° C., and then turn off the vacuum system.

[0036] Step 8: Place the diamond substrate after step 7 in a vacuum tube furnace, gradually heat it to 600°C at 4°C / min and keep it for 12 minutes. When the furnace temperature cools to room temperature, open the vacuum tube furnace, take out the CVD diamond, dry it, and store it in a vacuum bag. Example

[0037] This embodiment includes the following steps: Step 1: Clean the CVD diamond with ultrasonic acetone, ultrasonic ethanol, and ultrasonic deionized water for 15 minutes in sequence, repeat the ultrasonic cleaning twice, and then rinse, dehydrate and dry.

[0038] Step 2: Place the diamond substrate treated in step 1 in the vacuum chamber of the ion implantation equipment, install the Zr target, and adjust the background vacuum degree of the vacuum chamber of the ion implantation equipment to 7×10 -5 Pa and heated to 400 °C, turned on the ion implantation source, adjusted the ion implantation energy to 3 MeV, the ion beam intensity to 50 mA, and the ion implantation metering to 1.0 × 10 16 atoms / cm 2 , open the baffle, when the ion implantation dosage reaches a preset value, close the baffle, turn off the ion source, wait until the workpiece temperature drops below 100° C., turn off the vacuum system, and form a Zr transition layer on the diamond surface.

[0039] Step 3: Adjust the argon flow rate to a working pressure of 0.5 Pa and heat to 180° C. Turn on the magnetron Zr target source, set the constant power mode to 300 W, set the pulse width to 60 μs, set the pulse frequency to 600 Hz, and adjust the bias power supply voltage to 100 V to form a Zr bonding layer with a total thickness of 100 nm.

[0040] Step 4: Adjust the argon flow rate to the working gas pressure of 0.7Pa, and then use HiPIMS technology to deposit the second layer of metal Ni on the diamond substrate with the Zr bonding layer deposited. Set the power mode to 400W, set the pulse width to 80μs and keep it unchanged. Set the pulse frequency to 600Hz and adjust the bias power supply voltage to 150V to form a Ni welding barrier layer. The total thickness of the Ni welding barrier layer is 400nm.

[0041] Step 5: Adjust the argon flow rate to the working gas pressure of 0.5Pa, and then use HiPIMS technology to deposit the third layer of metal Au on the diamond substrate with Ni coating deposited, set the power mode to 200W, set the pulse width to 60μs, set the pulse frequency to 600Hz, and adjust the bias power supply voltage to 100V to form an Au welding layer. The total thickness of the Au welding layer is 180nm.

[0042] Step 6: After the Au welding layer is deposited, turn off all power supplies and the argon gas, wait until the temperature of the magnetron sputtering vacuum chamber drops below 100° C., and then turn off the vacuum system.

[0043] Step 7: Place the diamond substrate after step 6 in a vacuum tube furnace, gradually heat it to 600°C at 4°C / min and keep it at that temperature for 12 minutes. When the furnace temperature cools to room temperature, open the vacuum tube furnace, take out the CVD diamond, dry it and store it in a vacuum bag.

[0044] The technical solution of the present invention can have the following main beneficial effects: As an element with strong carbon affinity, Zr has good wettability with diamond and undergoes metallurgical chemical reaction with diamond. Through ion implantation, carbide ZrC is formed on the surface of diamond, which effectively improves the interfacial bonding of diamond. In addition, the formed carbide transition layer can effectively improve the degree of phonon mismatch between diamond and metal interface and reduce interfacial thermal resistance. Since the Zr layer is thin and easily oxidized at brazing temperature, a layer of Ni is plated on the basis of the Zr layer to effectively protect the Zr metal layer from damage. A layer of Au is plated on the Ni layer to allow better wetting of gold-tin alloy solder during welding and increase welding strength.

[0045] 2. Ion implantation technology can implant any element into the near-surface layer of the matrix material without being restricted by thermodynamics. Using ion implantation technology, Zr can be implanted into the diamond surface, which can produce more ZrC on the diamond surface and further improve the diamond interface bonding. And the dose and depth of ion implantation can be precisely controlled, which makes the modification process highly repeatable and consistent. In addition, traditional diamond surface metal selection methods such as vacuum evaporation plating and chemical plating have problems such as difficult to control the coating thickness, poor welding bonding, and environmental pollution. HiPIMS technology is not only environmentally friendly and pollution-free, but also can optimize the deposition process of the thin film by adjusting the pulse parameters, and accurately control the thickness and quality of the coating.

[0046] 3. Heat treatment helps the chemical reaction between the coating and the diamond to form a stable chemical bond. This bonding method is stronger than simple physical adsorption and can significantly improve the bonding strength between the diamond and the coating.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A heat sink diamond with surface gradient metallization, characterized in that: include: Diamond substrate; A Zr transition layer formed on the surface of the diamond; a Zr bonding layer formed on the Zr transition layer; a Ni solder barrier layer formed on the Zr adhesive layer; And, an Au solder layer is formed on the Ni solder barrier layer.

2. A heat sink diamond with surface gradient metallization according to claim 1, characterized in that: The total thickness of the Zr bonding layer is 80-100 nm; the total thickness of the Ni welding barrier layer is 300-450 nm; and the total thickness of the Au welding layer is 150-200 nm.

3. The heat sink diamond with surface gradient metallization according to claim 1, characterized in that: The Zr transition layer is formed by ion implantation, and the Zr bonding layer, the Ni welding barrier layer and the Au welding layer are formed by high-power pulse magnetron sputtering.

4. A method for preparing a heat sink diamond with a surface gradient metallization, characterized in that: The following steps are involved: Step 1: Substrate pretreatment: ultrasonic acetone cleaning, ultrasonic ethanol cleaning, ultrasonic deionized water rinsing, dehydration and drying of the CVD diamond in sequence; Step 2: ion implantation of Zr; placing the diamond treated in step 1 in an ion implantation device, and performing ion implantation using a Zr target to form a Zr transition layer; Step 3: Depositing a Zr transition layer; adjusting the argon flux and the working gas pressure in the magnetron sputtering vacuum chamber and heating it, turning on the magnetron Zr target source and the bias power supply, and depositing a Zr bonding layer; Step 4: depositing a Ni welding barrier layer; switching the magnetron sputtering power supply, target material and working gas pressure, and depositing a second layer of metal Ni as a solder resist metal on the diamond substrate of the Zr transition layer to form a Ni welding barrier layer; Step 5: depositing an Au welding layer; switching the magnetron sputtering power supply, target material and working gas pressure, and depositing a third layer of metal Au as a welding layer metal on the Ni welding barrier layer to form an Au welding layer; Step 6: After the Au welding layer is deposited, the power supply and the argon gas are turned off, and the vacuum system is turned off when the temperature of the magnetron sputtering vacuum chamber drops below 100° C.; Step 7: Place the diamond substrate after the treatment in step 6 into a vacuum tube furnace and heat it to 500-800° C. for insulation.

5. The preparation method according to claim 4, characterized in that: In step 1, the three washing times of ultrasonic acetone cleaning, ultrasonic ethanol, and ultrasonic deionized water rinsing are not less than 15 minutes respectively, and each washing is repeated at least 2-4 times; After step 2, the method further includes step 2.1: bias self-cleaning; placing the diamond substrate processed in step 2 into a magnetron sputtering vacuum chamber, adjusting the background vacuum degree of the magnetron sputtering vacuum chamber, and introducing argon gas to realize bias self-cleaning of the surface of the diamond substrate processed in step 2.

6. The preparation method according to claim 4, characterized in that: In step 2, the background vacuum degree of the vacuum chamber of the ion implantation equipment is less than 1×10 -4 Pa, heating temperature is 300℃~500℃, ion implantation energy is adjusted to 1~3MeV, ion beam intensity is adjusted to 1~100mA, ion implantation metering is 1.0×10 16 ~1.0×10 18 atoms / cm 2 .

7. The preparation method according to claim 4, characterized in that: In step 3, the background vacuum degree of the vacuum chamber of the magnetron sputtering equipment is lower than 7×10 -4 Pa, working gas pressure is not less than 10Pa, bias power supply is 200~500V.

8. The preparation method according to claim 4, characterized in that: In step 4, the working gas pressure of the vacuum chamber of the magnetron sputtering equipment is 0.4~1Pa, and the heating temperature is 100~260°C; the Zr target power supply is a HiPIMS power supply, and the constant power mode is set to 200~400W, the pulse width is 60~100μs, and the pulse frequency is 400~600Hz; the bias power supply is a DC power supply, and the bias size is set to 80~160V; the thickness of the Zr bonding layer is 80~100nm.

9. The preparation method according to claim 4, characterized in that: In step 5, the Ni target adopts a HiPIMS power supply, sets a constant power mode of 300-500W, a pulse width of 80-120μs, and a pulse frequency of 400-600Hz; the bias power supply is a DC power supply, the bias voltage is set to 100-180V, and the working gas pressure is 0.6-1Pa; the total thickness of the Ni welding barrier layer is 300-450nm.

10. The preparation method according to claim 4, characterized in that: In step six, the Au target uses a HiPIMS power supply, and the constant power mode is set to 150~250W, the pulse width is 60~100μs, and the pulse frequency is 300~600Hz; the bias power supply is a DC power supply, the bias size is set to 80~160V, and the working gas pressure is 0.4~1Pa; the total thickness of the Au coating is 150~200nm.

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