Superhard film layer and preparation method thereof

Abstract

The invention discloses a superhard film layer and a preparation method thereof. The superhard film layer comprises a base layer; the wear-resistant layer is arranged at the top of the base layer and is used for enhancing scratch resistance and fatigue resistance; the silicon oxynitride layer is arranged at the top of the wear-resistant layer and is used for adjusting the hardness and structural compatibility between different film layers; the titanium and zirconium doped silicon nitride layer is arranged at the top of the silicon oxynitride layer; the hydrogen-containing gradient silicon oxynitride layer is arranged on the top of the titanium-zirconium-doped silicon nitride layer, titanium, zirconium and hydrogen elements are introduced into the film layer, and the gradient film layer design is adopted, so that the hardness, the wear resistance and the corrosion resistance of the film layer are remarkably improved. A hardness test shows that the hardness of the prepared super-hard film layer is remarkably improved compared with that of a traditional film layer, and the prepared super-hard film layer can effectively resist scraping and abrasion in daily use and improve the service life and imaging stability of a lens in practical application such as a camera lens.

Description

Technical Field

[0001] The invention relates to the technical field of protective films, in particular to a superhard film layer and a preparation method thereof. Background Art

[0002] In the fields of camera lenses, electronic equipment outer covers, and optical lenses, in order to meet actual use requirements, it is necessary to coat their surfaces to improve their performance. However, the existing film preparation methods have some limitations in these applications, such as insufficient hardness of the film, weak bonding between the film and the substrate, and a single film structure, which cannot fully meet the use requirements under various complex working conditions. At the same time, some traditional coating technologies are difficult to accurately control the thickness, uniformity, and overall performance of each film layer when preparing multi-layer super-hard film layers, resulting in unstable film quality, which limits its application effect in these high-performance application scenarios. For example, in camera lens applications, insufficient hardness of the film layer will cause the lens to be easily scratched, affecting the imaging quality; if the film layer of the outer cover of the electronic equipment has poor corrosion resistance and wear resistance, it will reduce the service life and appearance quality of the equipment; and for optical lenses, the optical properties and stability of the film layer are also key factors affecting its performance, and the existing film preparation technology is difficult to meet these requirements. Summary of the invention

[0003] The object of the present invention is to provide a superhard film layer and a preparation method thereof to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a superhard film layer, comprising:

[0005] Base layer;

[0006] A wear-resistant layer, which is placed on top of the base layer to enhance scratch resistance and fatigue resistance;

[0007] A silicon oxynitride layer, which is placed on top of the wear-resistant layer and is used to adjust the hardness and structural compatibility between different film layers;

[0008] A titanium zirconium doped silicon nitride layer, wherein the titanium zirconium doped silicon nitride layer is disposed on top of the silicon oxynitride layer;

[0009] A hydrogen-containing gradient silicon oxynitride layer, the hydrogen-containing gradient silicon oxynitride layer is placed on top of the titanium zirconium doped silicon nitride layer, the hydrogen-containing gradient silicon oxynitride layer forms a gradient transition with the titanium zirconium doped silicon nitride layer and contains hydrogen;

[0010] A reinforcement layer, which is disposed on top of the hydrogen-containing gradient silicon oxynitride layer to provide additional hardness, increase impact resistance and improve the durability of the film surface;

[0011] A protective layer, the protective layer being placed on top of the reinforcing layer;

[0012] Preferably, both the base layer and the protective layer are silicon oxide layers, the base layer has a thickness ranging from 40 to 60 nm, and the protective layer has a thickness ranging from 50 to 60 nm;

[0013] Preferably, the reinforcement layer and the gradient silicon oxynitride layer containing hydrogen form a gradient transition, and the wear-resistant layer and the reinforcement layer are both silicon nitride layers;

[0014] Preferably, the thickness of the wear-resistant layer is in the range of 70-90 nm, and the thickness of the reinforcing layer is in the range of 70-80 nm;

[0015] Preferably, the thickness of the titanium zirconium doped silicon nitride layer is 60-80 nm;

[0016] Preferably, the thickness of the hydrogen-containing gradient silicon oxynitride layer is 70-80 nm;

[0017] A method for preparing a superhard film layer, characterized in that it comprises the following steps:

[0018] S1. Vacuum treatment: placing the substrate material in a vacuum chamber of a medium frequency sputtering coating device and performing vacuum treatment on the chamber;

[0019] S2. Sputtering coating of the first silicon oxide layer: install a silicon oxide target with a purity of 99.99%, adjust the frequency and power of the medium frequency power supply, introduce protective gas, control the bias voltage to -100V, perform sputtering, control the sputtering rate and film thickness, and use an optical film thickness monitor for monitoring;

[0020] S3. Sputtering coating of the second silicon nitride layer: replace the target material with a silicon nitride target material with a purity of 99.95%, adjust the frequency of the medium frequency power supply to maintain at 40kHz, the power to 1000W, introduce argon gas, adjust the bias voltage to -120V, perform sputtering, monitor the plasma state, and ensure the quality of the film layer;

[0021] S4. Sputtering coating of the third silicon oxynitride layer: using silicon oxynitride target, preheating the target, adjusting the flow of argon and oxygen, introducing a proper amount of oxygen, adjusting the power to 900 W, setting the bias voltage to -110 V, monitoring the chemical composition of the film layer, and ensuring the stoichiometric ratio of silicon oxynitride;

[0022] S5. Sputtering coating of the fourth titanium-zirconium doped silicon nitride layer: Use a composite target or evaporation source method to dope titanium and zirconium elements, adjust the medium frequency power supply to 1200W, control the argon flow and bias voltage to ensure doping uniformity, and use EDS or AES for real-time monitoring to ensure uniform distribution of elements;

[0023] S6. Sputtering coating of the fifth layer of hydrogen-containing gradient silicon oxynitride layer: using a mixed target material containing silicon oxynitride and silicon nitride, gradually transitioning to silicon oxynitride, controlling the flow rates of argon and hydrogen, and adjusting the flow rates of oxygen or nitrogen to ensure the quality of the gradient film layer;

[0024] S7. Sputtering coating of the sixth silicon nitride layer: replace the target material with a silicon nitride target material, adjust the medium frequency power supply power to 1050W, the argon gas flow rate to 42sccm, perform sputtering, and use a Raman spectrometer to monitor the film structure to ensure the film quality;

[0025] S8. Sputtering coating of the seventh silicon oxide layer: replace the target material with a silicon oxide target material, adjust the power to 850 W, the argon flow rate to 32 sccm, and the bias voltage to -105 V; perform sputtering, and use an ellipsometer to monitor the refractive index of the film layer to determine the quality of the film layer.

[0026] Preferably, the argon gas flow in S3 is adjusted to 40sccm and is precisely controlled using a mass flow controller with a flow control accuracy of ±0.1sccm. The chamber bias is adjusted to -120V, a high-precision bias power supply is used, and the bias fluctuation monitoring function is turned on to control the bias fluctuation within ±2V.

[0027] Preferably, in S4, a proper amount of oxygen is mixed into the argon as a reaction gas, the argon flow rate is 35 sccm, and the oxygen flow rate is 5 sccm. Independent mass flow controllers are used to control the flow rates of argon and oxygen, respectively, to ensure the accuracy and stability of the gas flow rates.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] By introducing titanium, zirconium and hydrogen elements into the film layer and adopting a gradient film layer design, the hardness, wear resistance and corrosion resistance of the film layer are significantly improved. Hardness tests show that the hardness of the prepared superhard film layer is significantly improved compared to traditional film layers. In practical applications, such as on camera lenses, it can effectively resist scratches and wear in daily use, and improve the service life and imaging stability of the lens; on the outer cover of electronic equipment, it can better resist the erosion of the external environment and improve the durability of the equipment.

[0030] Through the gradient film layer design, especially in the transition area between different film layers, the interface bonding problem caused by material and performance mutations is avoided, the overall performance of the film layer is made more uniform, the bonding strength between the film layer and the substrate is improved, the risk of film peeling or cracking is reduced, and the reliability of the film layer in complex environments is enhanced.

[0031] The thickness range of each layer is accurately controlled, and a variety of high-precision monitoring and control methods are used in the preparation process, such as optical film thickness monitors, power feedback control systems, high-precision mass flow controllers, etc., to ensure accurate control of the thickness and performance of each film layer and improve the consistency and stability of the product.

[0032] Element doping and gradient changes ensure the uniformity of element doping and the smooth transition of gradient film layers by adopting precise mixed target preparation methods, evaporation source control, ion implantation technology, and precise adjustment of gas flow and process parameters, reducing performance deviations caused by process fluctuations and improving product repeatability and quality stability.

[0033] Different combinations of process conditions can be achieved by adjusting the magnetic field, plasma source and its parameters, providing more adjustment space for further optimizing the film performance. It has good scalability and can develop films with more special properties based on subsequent research and application expansion. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the layer structure of the superhard film layer of the present invention;

[0035] Figure 2 The present invention is a flow chart of the preparation method.

[0036] In the figure: 1. base layer; 2. wear-resistant layer; 3. silicon oxynitride layer; 4. titanium zirconium doped silicon nitride layer; 5. hydrogen-containing gradient silicon oxynitride layer; 6. enhancement layer; 7. protective layer. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] See also Figure 1-Figure 2The present invention provides a technical solution: a superhard film layer, comprising: a base layer 1; a wear-resistant layer 2 plated on the top of the base layer 1, used to enhance scratch resistance and fatigue resistance; a silicon oxynitride layer 3 plated on the top of the wear-resistant layer 2, used to adjust the hardness and structural compatibility between different film layers; a titanium zirconium doped silicon nitride layer 4 plated on the top of the silicon oxynitride layer 3; a hydrogen-containing gradient silicon oxynitride layer 5 plated on the top of the titanium zirconium doped silicon nitride layer 4, the hydrogen-containing gradient silicon oxynitride layer 5 forms a gradient transition with the titanium zirconium doped silicon nitride layer 4 and contains hydrogen; an enhancement layer 6 plated on the top of the hydrogen-containing gradient silicon oxynitride layer 5, used to provide additional Hardness, increase impact resistance and enhance the durability of the film surface; the protective layer 7 is plated on the top of the reinforcement layer 6; the base layer 1 and the protective layer 7 are both silicon oxide layers, the thickness of the base layer 1 is in the range of 40-60nm, and the thickness of the protective layer 7 is 50-60nm; the reinforcement layer 6 and the hydrogen-containing gradient silicon oxynitride layer 5 form a gradient transition, and the wear-resistant layer 2 and the reinforcement layer 6 are both silicon nitride layers; the thickness of the wear-resistant layer 2 is in the range of 70-90nm, and the thickness of the reinforcement layer 6 is 70-80nm; the thickness of the titanium-zirconium doped silicon nitride layer 4 is 60-80nm; the thickness of the hydrogen-containing gradient silicon oxynitride layer 5 is 70-80nm.

[0039] It should be noted that the base layer 1 (silicon oxide layer) of the present invention is used as the bottom layer of the film layer, and the base layer provides preliminary adhesion for the entire film layer; thickness: 40-60nm; wear-resistant layer 2 (silicon nitride layer) is used to enhance the scratch resistance and fatigue resistance of the film layer; thickness: 70-90nm; material: silicon nitride, which has high hardness and good wear resistance; silicon nitride oxide layer 3 is used to adjust the hardness difference between the film layers, ensure the structural compatibility between different layers, and play a transition role; material: silicon nitride oxide, which has a certain hardness and chemical stability; titanium zirconium doped silicon nitride layer 4 is doped with titanium zirconium elements to help improve the hardness and high temperature resistance of the film layer, and at the same time increase the oxidation resistance of the film layer; thickness: 60-80nm; hydrogen-containing gradient silicon nitride oxide layer 5 forms a gradient transition, provides additional hardness, and improves the impact resistance and durability of the film layer. The hydrogen-containing component also contributes to the stability and flexibility of the film layer; thickness: 70-80nm; reinforcement layer 6 (silicon nitride layer) enhances the hardness, impact resistance and surface durability of the film layer. It forms a transition layer with the hydrogen-containing gradient silicon oxynitride layer 5 to improve the overall performance of the entire film layer; thickness: 70-80nm; material: silicon nitride; protective layer 7 (silicon oxide layer) is the final protective layer to protect the film layer from the influence of the external environment, such as corrosion, oxidation, etc.; thickness: 50-60nm; through multi-layer design, the compatibility and performance optimization between the layers are ensured. The use of silicon nitride, silicon oxynitride and doped titanium zirconium and other materials makes the film layer have excellent hardness, wear resistance, scratch resistance, impact resistance, fatigue resistance and durability. The gradient transition between different layers helps to reduce the stress difference between the layers and improve the overall stability and performance of the film layer.

[0040] A method for preparing a superhard film layer comprises the following steps:

[0041] S1. Vacuum chamber evacuation

[0042] S11. Pre-vacuum stage:

[0043] Start the mechanical vacuum pump to reduce the air pressure in the chamber to about $10^{-1}$Pa.

[0044] Closely monitor the rate of gas pressure drop to ensure it is stable to avoid affecting subsequent coating.

[0045] S12. High vacuum stage:

[0046] Start the diffusion pump or molecular pump to further reduce the gas pressure to $10^{-4}$Pa.

[0047] When using a diffusion pump, preheat the diffusion pump oil to a set temperature (e.g., 150°C) and keep the oil temperature stable.

[0048] Use a high vacuum gauge (such as an ionization gauge) to accurately measure the chamber pressure. When the pressure drops to $10^{-4}$Pa, continue to pump the air for about 30 minutes to ensure that gas impurities are completely removed and the vacuum degree is stabilized.

[0049] S2. Sputtering coating of the first silicon oxide layer

[0050] S21. Target installation and cleaning:

[0051] A 99.99% pure silicon oxide target is mounted to the sputtering source and the surface is cleaned to remove any impurities.

[0052] S22. Coating process:

[0053] The medium frequency power supply frequency was adjusted to 40kHz, the power was set to 800W, and a power feedback control system was adopted to control the fluctuation within ±1%.

[0054] Argon gas was introduced through a high-precision mass flow controller, and the flow rate was set to 30 sccm. The chamber bias voltage was set to -100 V, and the bias voltage change was monitored in real time.

[0055] Start sputtering of silicon oxide layer, set the sputtering rate to 3nm / min, the coating time to about 17 minutes, and reach a thickness of 50nm. Use an optical film thickness monitor to monitor the film thickness in real time, and automatically stop sputtering when the predetermined thickness is reached.

[0056] S3. Second silicon nitride layer sputtering coating

[0057] S31. Target replacement:

[0058] After the first layer of silicon oxide film is completed, the target material is replaced with a silicon nitride target with a purity of 99.95% using a target material replacement device.

[0059] S32. Coating process:

[0060] Adjust the medium frequency power supply frequency to maintain 40kHz, set the power to 1000W, and gradually increase the power by 50W each time.

[0061] The argon gas flow rate was adjusted to 40 sccm, the chamber bias voltage was set to -120 V, and the bias voltage was adjusted in real time to keep the fluctuation within ±2 V.

[0062] The sputtering rate of silicon nitride was set to 4 nm / min, the deposition time was about 20 minutes, and the thickness was 80 nm. The plasma state was monitored by a Langmuir probe, and the process parameters were fine-tuned as needed.

[0063] S4. The third silicon oxynitride layer is sputtered

[0064] S41. Target preheating and gas configuration:

[0065] Use a silicon oxynitride target with a purity of 99.9%, and preheat the target temperature to 200°C in advance to ensure sputtering efficiency and target stability.

[0066] Oxygen was added to the argon gas, with an argon flow rate of 35 sccm and an oxygen flow rate of 5 sccm. Independent flow controllers were used to precisely control the gas flow rates.

[0067] S42. Coating process:

[0068] Continue to use 40kHz frequency, the intermediate frequency power supply power is 900W, the chamber bias is set to -110V, and the power and bias are adjusted in real time to ensure stability.

[0069] The sputtering rate of silicon oxynitride is 3.5nm / min, and the coating time is about 17 minutes to prepare a 60nm thick silicon oxynitride layer. The chemical composition of the film layer is monitored in real time using an online spectral analysis device to ensure that the stoichiometric ratio of silicon oxynitride is within the expected range.

[0070] S5. Sputtering coating of the fourth titanium-zirconium doped silicon nitride layer

[0071] S51. Target selection and preparation:

[0072] Replace with silicon nitride target (purity 99.95%), add titanium and zirconium elements into it. The titanium zirconium doped silicon nitride layer can be prepared by composite target method or evaporation source method.

[0073] S52. Composite target method:

[0074] The composite target material of titanium, zirconium and silicon nitride is refined and pressed and sintered using isostatic pressing technology to ensure that the target material is uniform and dense.

[0075] The power was adjusted to 1200 W, the argon flow rate was 35 sccm, and a power feedback control system was used to ensure stability.

[0076] The sputtering rate was set to 4.5 nm / min, the thickness was 70 nm, and the coating time was about 16 minutes. EDS was used to monitor the doping uniformity of the elements in real time.

[0077] S53. Evaporation source method:

[0078] Install titanium and zirconium evaporation sources, and control the evaporation source temperature (titanium 1500°C, zirconium 1400°C).

[0079] The power was adjusted to 1200 W, the argon gas flow rate was 35 sccm, the chamber bias was -130 V, and the bias fluctuation was kept within ±2 V.

[0080] The sputtering rate of titanium zirconium doped silicon nitride was set to 4.5nm / min, and the thickness of the film was 70nm. The coating time was about 16 minutes. AES was used to monitor the depth distribution of the elements to ensure that the elements were evenly distributed in the film layer.

[0081] S6. Sputtering coating of the fifth layer of hydrogen-containing gradient silicon oxynitride layer

[0082] S61. Gradient membrane design and gas adjustment:

[0083] A mixed target containing silicon oxynitride and silicon nitride was used, and an appropriate amount of hydrogen was mixed into the argon gas. The initial gas flow rate was 35 sccm argon and 2 sccm hydrogen.

[0084] During the coating process, the flow rates of oxygen and nitrogen were gradually adjusted, the flow rates of argon and hydrogen were kept stable, and the bias voltage was adjusted to -115V in real time.

[0085] S62. Coating process:

[0086] The average sputtering rate was set to 3.8 nm / min, and the coating time was adjusted according to the gradient change, and the final thickness was 65 nm. The surface morphology of the film layer was monitored using SEM to ensure that the surface of the film layer was flat during the gradient change process.

[0087] S7. Sputtering coating of the sixth silicon nitride layer

[0088] S71. Target replacement and gas adjustment:

[0089] The target material was replaced with silicon nitride (purity 99.95%), and the argon gas flow rate was adjusted to 42 sccm, and the chamber bias was set to -125V.

[0090] S72. Coating process:

[0091] The medium frequency power supply was set to 1050W, the sputtering rate was 4.1nm / min, the coating time was about 18 minutes, and the thickness was 75nm. A Raman spectrometer was used to monitor the structural changes of the film in real time to ensure the quality of the film.

[0092] S8. Sputtering coating of the seventh silicon oxide layer

[0093] S81. Target replacement and gas configuration:

[0094] Finally, the target material was replaced with a silicon oxide target with a purity of 99.99%, and the replacement was completed in a vacuum environment.

[0095] S82. Coating process:

[0096] The intermediate frequency power supply frequency was 40 kHz, the power was set to 850 W, the argon gas flow rate was 32 sccm, and the chamber bias was set to -105 V.

[0097] The sputtering rate was set to 3.2 nm / min, the coating time was about 17 minutes, and the thickness was 55 nm. The refractive index of the film was monitored using an ellipsometer to ensure that the film quality met the requirements.

[0098] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A superhard film layer, characterized in that: include: Base layer; A wear-resistant layer, which is placed on top of the base layer to enhance scratch resistance and fatigue resistance; A silicon oxynitride layer, which is placed on top of the wear-resistant layer and is used to adjust the hardness and structural compatibility between different film layers; A titanium zirconium doped silicon nitride layer, wherein the titanium zirconium doped silicon nitride layer is disposed on top of the silicon oxynitride layer; A hydrogen-containing gradient silicon oxynitride layer, the hydrogen-containing gradient silicon oxynitride layer is placed on top of the titanium zirconium doped silicon nitride layer, the hydrogen-containing gradient silicon oxynitride layer forms a gradient transition with the titanium zirconium doped silicon nitride layer and contains hydrogen; A reinforcement layer, which is disposed on top of the hydrogen-containing gradient silicon oxynitride layer to provide additional hardness, increase impact resistance and improve the durability of the film surface; A protective layer, the protective layer being placed on top of the reinforcing layer; 2. The superhard film layer according to claim 1, characterized in that: The base layer and the protective layer are both silicon oxide layers, the base layer has a thickness ranging from 40 to 60 nm, and the protective layer has a thickness ranging from 50 to 60 nm; 3. The superhard film layer according to claim 1, characterized in that: The reinforcing layer and the gradient silicon nitride oxide layer containing hydrogen form a gradient transition, and the wear-resistant layer and the reinforcing layer are both silicon nitride layers; 4. The superhard film layer according to claim 3, characterized in that: The thickness of the wear-resistant layer is in the range of 70-90 nm, and the thickness of the reinforcing layer is in the range of 70-80 nm; 5. The superhard film layer according to claim 1, characterized in that: The thickness of the titanium zirconium doped silicon nitride layer is 60-80nm; 6. The superhard film layer according to claim 1, characterized in that: The thickness of the hydrogen-containing gradient silicon oxynitride layer is 70-80 nm; 7. A method for preparing a superhard film according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1. Vacuum treatment: placing the substrate material in a vacuum chamber of a medium frequency sputtering coating device and performing vacuum treatment on the chamber; S2. Sputtering coating of the first silicon oxide layer: install a silicon oxide target with a purity of 99.99%, adjust the frequency and power of the medium frequency power supply, introduce protective gas, control the bias voltage to -100V, perform sputtering, control the sputtering rate and film thickness, and use an optical film thickness monitor for monitoring; S3. Sputtering coating of the second silicon nitride layer: replace the target material with a silicon nitride target material with a purity of 99.95%, adjust the frequency of the medium frequency power supply to maintain at 40kHz, the power to 1000W, introduce argon gas, adjust the bias voltage to -120V, perform sputtering, monitor the plasma state, and ensure the quality of the film layer; S4. Sputtering coating of the third silicon oxynitride layer: using silicon oxynitride target, preheating the target, adjusting the flow of argon and oxygen, introducing a proper amount of oxygen, adjusting the power to 900 W, setting the bias voltage to -110 V, monitoring the chemical composition of the film layer, and ensuring the stoichiometric ratio of silicon oxynitride; S5. Sputtering coating of the fourth titanium-zirconium doped silicon nitride layer: Use a composite target or evaporation source method to dope titanium and zirconium elements, adjust the medium frequency power supply to 1200W, control the argon flow and bias voltage to ensure doping uniformity, and use EDS or AES for real-time monitoring to ensure uniform distribution of elements; S6. Sputtering coating of the fifth layer of hydrogen-containing gradient silicon oxynitride layer: using a mixed target material containing silicon oxynitride and silicon nitride, gradually transitioning to silicon oxynitride, controlling the flow rates of argon and hydrogen, and adjusting the flow rates of oxygen or nitrogen to ensure the quality of the gradient film layer; S7. Sputtering coating of the sixth silicon nitride layer: replace the target material with a silicon nitride target material, adjust the medium frequency power supply power to 1050W, the argon gas flow rate to 42sccm, perform sputtering, and use a Raman spectrometer to monitor the film structure to ensure the film quality; S8. Sputtering coating of the seventh silicon oxide layer: replace the target material with a silicon oxide target material, adjust the power to 850 W, the argon flow rate to 32 sccm, and the bias voltage to -105 V; perform sputtering, and use an ellipsometer to monitor the refractive index of the film layer to determine the quality of the film layer.

8. The method for preparing a superhard film layer according to claim 7, characterized in that: The argon gas flow rate in S3 is adjusted to 40sccm and is precisely controlled using a mass flow controller with a flow control accuracy of ±0.1sccm. The chamber bias is adjusted to -120V, a high-precision bias power supply is used, and the bias fluctuation monitoring function is turned on to control the bias fluctuation within ±2V.

9. The method for preparing a superhard film layer according to claim 7, characterized in that: In the S4, a proper amount of oxygen is mixed into the argon as a reaction gas, the argon flow rate is 35 sccm, and the oxygen flow rate is 5 sccm. Independent mass flow controllers are used to control the flow rates of argon and oxygen respectively to ensure the accuracy and stability of the gas flow rates.

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