A method for preparing an etching-resistant Ni hard mask layer

Abstract

The present invention provides a method for preparing an etch-resistant Ni hard mask layer, belonging to the fields of micro-nanofabrication and thin film technology. The present invention prepares a Ni film via magnetron sputtering. By regulating key process parameters during the magnetron sputtering process, such as the Ar / H2 gas flow ratio, sputtering pressure, substrate heating temperature, and sputtering power, the quality and performance of the Ni film can be controlled. Using this method, a Ni film without columnar structures, smooth surface, excellent corrosion resistance, high etching selectivity, and fast deposition rate is produced.

Description

Technical Field

[0001] The invention relates to the field of micro-nano processing and thin film technology, and in particular to a method for preparing an etching-resistant Ni hard mask layer. Background Art

[0002] Micro-nanofabrication technology is a key fabrication technique in modern microelectronic chips, optoelectronic chips, bio- and chemical-based microfluidics, microelectromechanical systems (MEMS), and multifunctional micro- and nanostructured surfaces. Plasma etching, a core process in micro- and nanofabrication, transfers a mask pattern onto the surface of a target substrate, ultimately enabling the fabrication of micro- and nano-devices and patterns. Commonly used masks include soft masks, such as photoresist masks and polymer masks like PMMA; and hard masks, typically made of metals like Al, Cr, Ti, and Ni, and inorganic non-metallic materials like SiO2, Si3N4, and Al2O3. However, these mask materials are primarily used as etching masks for conventional semiconductor materials like Si and Ge, and their compounds, and are relatively mature for fluorine-based gas plasma etching processes. As the application areas of micro- and nanostructured surfaces continue to expand, research and application of etching micro- and nanostructures on diverse substrates, such as spinel, II-VI compounds, and III-V compounds, are increasing. However, fluorine-based gases are ineffective due to their low chemical activity and low volatility of etching products on these materials, necessitating the use of more active chlorine-based etching gases. However, the aforementioned soft masks, including metal masks made of Al, Cr, and Ti, as well as inorganic non-metallic mask materials such as SiO2, Si3N4, and Al2O3, have poor resistance to chlorine-based plasma etching and limited etching selectivity compared to substrate materials, failing to meet the requirements for chlorine-based plasma etching. Therefore, the development of new mask materials and mask preparation processes is crucial.

[0003] Relatively speaking, Ni metal film has good etching resistance and is firmly bonded to the substrate, making it a commonly used etching mask material. In addition, due to its excellent corrosion resistance, ductility and wear resistance, Ni is also widely used in the fields of corrosion protection and wear resistance. In the document "Study on the Organization and Corrosion Resistance of Nickel-Based Composite Films Prepared by Magnetron Sputtering" (Sun Kang, Master's Thesis of Shandong University of Science and Technology, 2019), Ni-Zr, Ni-Cr-Zr and other Ni-based alloy films were prepared by magnetron sputtering using Ar as the sputtering gas, which have good corrosion resistance; in the document "Experimental Study on Electrodeposition of Nickel Films with Variable Current Waveform" (Zhang Huajin, Master's Thesis of Henan University of Technology, 2023), the document "Research on the Corrosion Resistance of Metal Nickel Plating for Conductor Interconnection" (Wang Yuequan, Master's Thesis of Shanghai Jiaotong University, 2017) and the document "Research on Metal Nickel Electrodeposition Process and Coating Structure" (Li Fubin, Master's Thesis of Lanzhou University, 2015), Ni metal films were prepared by electrodeposition technology to study the corrosion resistance of Ni films. Its corrosion resistance; in the document "Basic research on the application of laser-assisted preparation of micro-nanostructure flexible conductive films" (Gao Liang, master's thesis of Lanzhou University, 2020), Ni metal grid film was prepared by electrodeposition technology, and its transparent conductive properties were studied; in the document "Research on the deposition of metal nickel film on glass by DC magnetron sputtering" (Han Li. Surface Technology, 2012, Vol. 41, No. 6, p. 66), high-purity Ar was used as the sputtering gas to prepare Ni metal film by DC magnetron sputtering; the document "Preparation of nickel thin film and its metal silicide by thermal ALD technology" (Wu Liying, Qu Minni, Shen Zhiliang, Wang Ying, Cheng Xiulan. Micro-Nano Electronics Technology, 2019, Vol. 56, No. 6, p. 486) and the document "Plasma-Enhanced Atomic Layer Deposition of Ni”(Han-Bo-Ram Lee, Sung-Hwan Bang, Woo-Hee Kim, Gil Ho Gu, Young Kuk Lee, Taek-Mo Chung, Chang Gyoun Kim, Chan Gyung Park, and Hyungjun Kim. Japanese Journal of Applied Physics, 2010, 49(5): 05FA11-1-05FA11-4) used atomic layer deposition technology to prepare a high-purity, good conformal, continuous and smooth Ni metal film in the reaction temperature window of 250℃; the literature “Surface engineering for SiC etching with Ni electroplating masks” (Nour Beydoun, Mihai Lazar, Xavier Gassmann.International Semiconductor Conference (CAS), Oct. 2022, Poiana Brasov, Romania. pp. 119-122, 10.1109 / CAS56377.2022.9934701.hal-03856454) used electrodeposition technology to prepare a Ni mask for fluorine-based plasma etching of SiC substrates. The Ni film deposition rate was fast and the thickness was large; the paper "Fabrication of Nickel Plasma Etching Mask by Nano-Imprint Lithography and Electroless Plating" (Shingo Shimizu, Hideki Tanabe, Masaaki Yasuda, Yoshihiko Hirai. Journal of Photopolymer Science and In the paper “Study on Dry Etching of Silicon Carbide and Dielectrics with Metal Masks” (Chen Gang, Wang Quanhui, Li Li, Liu Haiqi, Bai Song. The 17th National Conference on Compound Semiconductors, Microwave Devices and Optoelectronic Devices, Kaifeng, October 13-14, 2012), a Ni mask was prepared by electron beam evaporation for fluorine-based plasma etching of SiC substrates and Si films, achieving a large etching selectivity. In the paper “Etching Selectivity and Surface Profile of GaN in the Ni,SiO2 and Photoresist Masks Using an Inductively Coupled Plasma” (Liann-Be CHANG, Su-Sir Liu and Ming-Jer JENG. Jpn. J. Appl. Phys., Part 1, 2001, 40(3A):1242-1243), a Ni film was prepared by electron beam evaporation technology and used as a chlorine-based plasma etching mask for GaN thin film to obtain a large etching selectivity; the literature "Using Ni masks in inductively coupled plasma etching of high density hole patterns in GaN" (David SYHsu; Chul Soo Kim; Charles R.Eddy, Jr.; Ronald T.Holm; Richard L.Henry; JACasey; V.A.Shamamian; A.Rosenberg. J.Vac.Sci.Technol.B, 2005, 23:1611–1614) used ion beam sputtering to prepare a Ni mask, which was used as a chlorine-based plasma etching mask for GaN thin films. The Ni film deposition rate was 7.4 nm / min, with a dense structure and a smooth surface.

[0004] Among the preparation and application of the above-mentioned Ni films and Ni masks or films, electrodeposition technology is the most widely used, with a fast deposition rate and a large Ni film thickness, but the deposited Ni film has a low adhesion strength, a loose structure, many pores, and a large surface roughness, so its corrosion resistance and etching resistance are poor; the atomic layer deposition Ni film has a dense structure, a smooth surface, and very little roughness, but the deposition rate is very low, and a metal organic compound precursor is used, so the efficiency is low and the cost is high; the liquid phase deposition technology has a simple process and high efficiency, but because it involves chemical reactions, it requires the use of precious metal Pd as a catalyst, and the liquid phase deposition process will have an adverse effect on the pre- and subsequent processes of device preparation; the electron beam evaporation Ni film, due to the inherent characteristics of low energy of the evaporated atoms, makes the Ni film poor in density, low in adhesion strength, and secondary sputtering occurs during the etching process; the ion beam sputtering deposition Ni film has a dense structure, high adhesion strength, and a smooth surface, but the sputtering rate is slow, the film thickness is small, and a large-caliber ion source with high technical difficulty and cost is required. Relatively speaking, DC magnetron sputtering and RF magnetron sputtering have great advantages in the preparation of metal films such as Ni, and are widely used in the preparation of devices and masks. However, the prepared Ni films are prone to severe columnar crystal structures, and the columnar crystal structures become more serious with the increase of deposition rate and film thickness, resulting in rough surface and poor density of the Ni film. Therefore, the prepared Ni film has insufficient etching resistance and corrosion resistance, which affects the accuracy of the etched pattern and the etching selectivity. Summary of the Invention

[0005] The object of the present invention is to provide a method for preparing an etching-resistant Ni hard mask layer, so as to solve the above-mentioned technical problems.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] The present invention provides a method for preparing an etching-resistant Ni hard mask layer, comprising the following steps:

[0008] A Ni film was deposited on the substrate surface by magnetron sputtering;

[0009] The magnetron sputtering method comprises the following steps:

[0010] The pretreated substrate is placed on the anode in the vacuum chamber of the magnetron sputtering coating machine. 99.99% high-purity Ni is used as the target material, Ar gas is used as the sputtering gas, and H2 gas is used as the etching gas. Under vacuum conditions, the Ni target is sputtered to grow a Ni film.

[0011] The vacuum condition is a vacuum degree of <8×10 -4 Pa.

[0012] Furthermore, the substrate heating temperature is 100-250°C.

[0013] Furthermore, the sputtering gas pressure in the vacuum chamber is 0.15-0.5 Pa.

[0014] Furthermore, the Ar gas flow rate is 25-40 sccm, and the H2 gas flow rate is 2.5-5.6 sccm.

[0015] Furthermore, the flow ratio of the Ar gas to the H2 gas is 7:1 to 10:1.

[0016] Furthermore, the sputtering power is 100-250W.

[0017] Beneficial effects of the present invention:

[0018] The present invention uses magnetron sputtering technology to prepare Ni thin film, and introduces an appropriate amount of H2 as etching gas into the vacuum chamber to regulate the growth process of the Ni film. H2 will be excited, decomposed and ionized in the plasma atmosphere in the vacuum chamber, obtaining H atoms and H with high energy and activity. + ions, H / H + It has a strong corrosive and etching effect, and will etch away the Ni atoms deposited on the substrate that are weakly bonded and have low diffusion ability, thereby inhibiting the growth of columnar crystals and helping to improve the density of the Ni film. The reduction of columnar structures can also reduce the surface roughness of the film. Since the Ni atoms at the junction of the columnar structures are highly active and prone to chemical reactions, they are preferentially corroded / etched during the corrosion or etching process, so the Ni film with a columnar structure has poor corrosion / etching resistance. The present invention effectively inhibits the growth of columnar structures, and the prepared Ni film has a dense structure and a smooth surface, thereby improving the corrosion resistance and etching resistance of the film. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a surface scanning electron microscope photograph of a Ni film deposited under process parameters of sputtering power 100 W, substrate temperature 100°C, gas pressure 0.5 Pa, Ar gas flow rate 25 sccm and H2 gas flow rate 2.5 sccm (Ar:H2 gas flow ratio 10:1);

[0020] Figure 2Cross-sectional scanning electron micrograph of a Ni film deposited under process parameters of sputtering power 100 W, substrate temperature 100°C, gas pressure 0.5 Pa, Ar gas flow rate 25 sccm, and H2 gas flow rate 2.5 sccm (Ar:H2 gas flow ratio 10:1);

[0021] Figure 3 Surface atomic force microscopy images of the Ni film deposited under process parameters of sputtering power 100 W, substrate temperature 100°C, gas pressure 0.5 Pa, Ar gas flow rate 25 sccm and H2 gas flow rate 2.5 sccm (Ar:H2 gas flow ratio 10:1);

[0022] Figure 4 This is a surface scanning electron micrograph of a Ni film deposited under process parameters of sputtering power 190 W, substrate temperature 150°C, gas pressure 0.3 Pa, Ar gas flow rate 25 sccm and H2 gas flow rate 2.5 sccm (Ar:H2 gas flow ratio 10:1);

[0023] Figure 5 This is a scanning electron micrograph of a cross section of a Ni film deposited under process parameters of sputtering power 190 W, substrate temperature 150°C, gas pressure 0.3 Pa, Ar gas flow rate 25 sccm, and H2 gas flow rate 2.5 sccm (Ar:H2 gas flow ratio 10:1);

[0024] Figure 6 This is an atomic force microscope image of the surface of the Ni film deposited under the process parameters of sputtering power 190W, substrate temperature 150℃, gas pressure 0.3Pa, Ar gas flow rate 25sccm and H2 gas flow rate 2.5sccm (Ar:H2 gas flow ratio 10:1);

[0025] Figure 7 Surface scanning electron micrograph of the deposited Ni film under process parameters of sputtering power 250 W, substrate temperature 150 ° C, gas pressure 0.3 Pa, Ar gas flow rate 35 sccm and H2 gas flow rate 3.5 sccm (Ar:H2 gas flow ratio 10:1);

[0026] Figure 8 This is a surface scanning electron micrograph of a Ni film deposited under process parameters of sputtering power 250 W, substrate temperature 250°C, gas pressure 0.15 Pa, Ar gas flow rate 40 sccm, and H2 gas flow rate 5.6 sccm (Ar:H2 gas flow ratio ~7:1);

[0027] Figure 9 This is a surface optical microscope photograph of the Ni film deposited after corrosion under H2 gas conditions according to Example 4 of the present invention;

[0028] Figure 10This is an optical microscope photo of the surface of the Ni film deposited after corrosion under the condition without adding H2 gas;

[0029] Figure 11 This is a scanning electron microscope photograph of a pattern etched after a Ni mask is prepared on a ZnS surface under H2 gas conditions in Example 4 of the present invention;

[0030] Figure 12 This is a scanning electron microscope photograph of a pattern etched after a Ni mask is prepared on the surface of magnesium aluminum spinel (MgAl2O4) under H2 gas conditions in Example 3 of the present invention. DETAILED DESCRIPTION

[0031] The present invention provides a method for preparing an etching-resistant Ni hard mask layer, comprising the following steps:

[0032] A Ni film was deposited on the substrate surface by magnetron sputtering;

[0033] The magnetron sputtering method comprises the following steps:

[0034] The pretreated substrate is placed on the anode in the vacuum chamber of the magnetron sputtering coating machine. 99.99% high-purity Ni is used as the target material, Ar gas is used as the sputtering gas, and H2 gas is used as the etching gas. Under vacuum conditions, the Ni target is sputtered to grow a Ni film.

[0035] The vacuum condition is a vacuum degree of <8×10 -4 Pa, substrate temperature is 100℃~250℃.

[0036] In the present invention, the vacuum condition is preferably a vacuum degree of <6×10 -4 Pa, more preferably <3×10 -4 Pa.

[0037] In the present invention, the substrate temperature is 100 to 250°C, preferably 120 to 240°C, more preferably 150 to 240°C, and even more preferably 200 to 220°C.

[0038] In the present invention, the sputtering gas pressure in the vacuum chamber is 0.1-0.5 Pa, preferably 0.2-0.4 Pa, and more preferably 0.3 Pa.

[0039] In the present invention, the Ar gas flow rate is 25 to 40 sccm, preferably 30 to 35 sccm, and more preferably 30 sccm; the H2 gas flow rate is 2.5 to 5.6 sccm, preferably 3 to 5 sccm, and more preferably 3.5 to 4.5 sccm.

[0040] In the present invention, the flow ratio of the Ar gas to the H2 gas is 7:1 to 10:1, preferably 10:1.

[0041] In the present invention, the sputtering power is 100 to 250 W, preferably 120 to 250 W, more preferably 150 to 250 W, and even more preferably 190 to 250 W.

[0042] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0043] Example 1

[0044] Step 1: Pre-treat the substrate

[0045] The polished Si substrate was first rinsed with deionized water to remove surface particles; then the substrate surface was wiped with cotton wool soaked in acetone and alcohol to remove organic pollutants such as grease on the surface; then the substrate was ultrasonically cleaned with acetone and deionized water in turn; and then the substrate was blown dry.

[0046] Step 2: Prepare Ni film by magnetron sputtering

[0047] The preparation process is as follows:

[0048] Step 2.1: Place the pre-treated substrate on the anode in the vacuum chamber of the magnetron sputtering coating machine, place the 99.99% high-purity Ni target on the cathode, and pump the background vacuum of the coating machine to <8×10 -4 Pa, and heat the substrate to 100°C.

[0049] Step 2.2: Ar gas and H2 gas are introduced into the vacuum chamber. The Ar gas flow rate is set to 25 sccm, the H2 gas flow rate is set to 2.5 sccm, the Ar:H2 gas flow ratio is 10:1, and the vacuum chamber pressure is set to 0.5 Pa.

[0050] Step 2.3: Start the sputtering process with a discharge, set the sputtering power to 100 W, and the sputtering time to 60 minutes.

[0051] Step 2.4: After sputtering, wait for the substrate temperature to cool to room temperature and remove the sample.

[0052] Figure 1 : is a surface scanning electron micrograph of the Ni film prepared in Example 1 of the present invention. Figure 1 It can be seen that the surface of the Ni film is smooth, flat and clean, the grains are small and uniform (particle size ~15nm) and the structure is dense. Figure 2 : is a scanning electron micrograph of the cross section of the Ni film prepared in Example 1 of the present invention. Figure 2It can be seen that the Ni film does not have an obvious columnar crystal structure, and the internal structure is dense without holes or gaps. Figure 3 This is an atomic force micrograph of the surface of the Ni film prepared in Example 1 of the present invention. Figure 3 It can be seen that the surface roughness of the Ni film is only 0.8 nm. According to the test, the deposition rate of the Ni film is 17 nm / min.

[0053] Example 2

[0054] Step 1: Pre-treat the substrate

[0055] The polished ZnS substrate was first rinsed with deionized water to remove surface particles; then the substrate surface was wiped with absorbent cotton soaked in acetone and alcohol to remove organic pollutants such as grease on the surface; then the substrate was ultrasonically cleaned with acetone and deionized water in turn; and then the substrate was blown dry.

[0056] Step 2: Prepare Ni film by magnetron sputtering

[0057] The preparation process is as follows:

[0058] Step 2.1: Place the pre-treated substrate on the anode in the vacuum chamber of the magnetron sputtering coating machine, place the 99.99% high-purity Ni target on the cathode, and pump the background vacuum of the coating machine to <8×10 -4 Pa, and heat the substrate to 150°C.

[0059] Step 2.2: Ar gas and H2 gas are introduced into the vacuum chamber. The Ar gas flow rate is set to 25 sccm, the H2 gas flow rate is set to 2.5 sccm, the Ar:H2 gas flow ratio is 10:1, and the vacuum chamber pressure is set to 0.3 Pa.

[0060] Step 2.3: Start the sputtering process with a discharge, set the sputtering power to 190W, and the sputtering time to 60 minutes.

[0061] Step 2.4: After sputtering, wait for the substrate temperature to cool to room temperature and remove the sample.

[0062] Figure 4 : is a surface scanning electron micrograph of the Ni film prepared in Example 2 of the present invention. Figure 4 It can be seen that the surface of the Ni film is smooth, flat and clean, the grains are small and uniform (particle size ~20nm) and the structure is dense. Figure 5 : is a scanning electron micrograph of the cross section of the Ni film prepared in Example 2 of the present invention. Figure 5 It can be seen that the columnar crystal structure of the Ni film is very weak, and the internal structure is dense without holes or gaps. Figure 6This is an atomic force micrograph of the surface of the Ni film prepared in Example 2 of the present invention. Figure 6 It can be seen that the surface roughness of the Ni film is only 0.98nm. According to the test, the deposition rate of the Ni film is 22nm / min.

[0063] Example 3

[0064] Step 1: Pre-treat the substrate

[0065] The polished MgAl2O4 substrate was first rinsed with deionized water to remove surface particles; then the substrate surface was wiped with cotton wool soaked in acetone and alcohol to remove organic pollutants such as grease on the surface; then the substrate was ultrasonically cleaned with acetone and deionized water in sequence; and then the substrate was blown dry.

[0066] Step 2: Prepare Ni film by magnetron sputtering

[0067] The preparation process is as follows:

[0068] Step 2.1: Place the pre-treated substrate on the anode in the vacuum chamber of the magnetron sputtering coating machine, place the 99.99% high-purity Ni target on the cathode, and pump the background vacuum of the coating machine to <8×10 -4 Pa, and heat the substrate to 150°C.

[0069] Step 2.2: Ar gas and H2 gas are introduced into the vacuum chamber. The Ar gas flow rate is set to 35 sccm, the H2 gas flow rate is set to 3.5 sccm, the Ar:H2 gas flow ratio is 10:1, and the vacuum chamber pressure is set to 0.3 Pa.

[0070] Step 2.3: Start the sputtering process with a discharge, set the sputtering power to 250W, and the sputtering time to 60 minutes.

[0071] Step 2.4: After sputtering, wait for the substrate temperature to cool to room temperature and remove the sample.

[0072] Figure 7 : is a surface scanning electron micrograph of the Ni film prepared in Example 3 of the present invention. Figure 7 It can be seen that the Ni film has a smooth, flat and clean surface, uniform grains (grain size ~50nm) and a dense structure. According to tests, the surface roughness of the Ni film is ~2.5nm, and the deposition rate is ~32nm / min.

[0073] Example 4

[0074] Step 1: Pre-treat the substrate

[0075] The polished ZnS substrate was first rinsed with deionized water to remove surface particles; then the substrate surface was wiped with absorbent cotton soaked in acetone and alcohol to remove organic pollutants such as grease on the surface; then the substrate was ultrasonically cleaned with acetone and deionized water in turn; and then the substrate was blown dry.

[0076] Step 2: Prepare Ni film by magnetron sputtering

[0077] The preparation process is as follows:

[0078] Step 2.1: Place the pre-treated substrate on the anode in the vacuum chamber of the magnetron sputtering coating machine, place the 99.99% high-purity Ni target on the cathode, and pump the background vacuum of the coating machine to <8×10 -4 Pa, and heat the substrate to 250°C.

[0079] Step 2.2: Ar gas and H2 gas are introduced into the vacuum chamber. The Ar gas flow rate is set to 40 sccm, the H2 gas flow rate is set to 5.6 sccm, and the Ar:H2 gas flow ratio is ~7:1. The pressure in the vacuum chamber is set to 0.15 Pa.

[0080] Step 2.3: Start the sputtering process with a discharge, set the sputtering power to 250W, and the sputtering time to 60 minutes.

[0081] Step 2.4: After sputtering, wait for the substrate temperature to cool to room temperature and remove the sample.

[0082] Figure 8 : is a surface scanning electron micrograph of the Ni film prepared in Example 4 of the present invention. Figure 8 The Ni film has a smooth, flat, and clean surface, containing grains of varying sizes (average diameter ~65nm) and a dense structure. Tests have shown that the surface roughness of the Ni film is ~2.94nm, and the deposition rate is ~40nm / min.

[0083] Figure 9 The corrosion test results of the Ni film prepared in Example 4 of the present invention are as follows: the corrosion conditions are: immersion in 3.5% NaCl solution at 45°C for 48 hours. For comparison, the Ni film was prepared under the same deposition process parameters without adding H2 gas, and the corrosion test was carried out under the same conditions. The results are shown in Figure 2. Figure 10 As shown. Figure 9 and Figure 10It can be seen that in the method of the present invention, H2 gas is added, and only discrete corrosion pits are produced on the surface of the prepared Ni film. The corrosion pits have a low density and a small area, so the degree of corrosion is very small. However, the Ni film prepared without adding H2 gas produces corrosion cracks in addition to the corrosion pits, and the density of the cracks and pits is very large, and the cracks are very long, so the corrosion is serious.

[0084] Figure 11 The Ni film prepared in Example 4 of the present invention is an etching mask for a microstructure etched on a ZnS substrate, wherein the Ni film thickness is 280 nm (deposition time is 7 min), the etching depth is 5 μm, and the etching selectivity is 17.86:1. The ICP etching conditions are: excitation power 400 W, bias power 240 W, BCl3 gas flow rate 40 sccm, Ar gas flow rate 20 sccm, gas pressure 1 Pa, and time 70 min. It can be seen that the Ni film prepared by the method of the present invention has good resistance to chlorine-based plasma etching. After etching, the Ni mask remains intact and has a large etching selectivity, making it suitable as an etching mask material for II-VI compound semiconductors.

[0085] Figure 12 The Ni film prepared in Example 3 of the present invention is an etching mask for a microstructure etched on a magnesium aluminum spinel (MgAl2O4) substrate, wherein the Ni film thickness is 480 nm (deposition time is 15 min), the etching depth is 2.4 μm, and the etching selectivity is 5.09:1. The ICP etching conditions are: excitation power 400 W, bias power 240 W, BCl3 gas flow rate 40 sccm, Ar gas flow rate 20 sccm, gas pressure 1 Pa, and time 70 min. It can be seen that the Ni film prepared by the method of the present invention has good resistance to chlorine-based plasma etching. After etching, the Ni mask remains intact and has a relatively large etching selectivity, making it suitable as an etching mask material for MgAl2O4.

[0086] As can be seen from the above examples, the present invention provides a method for preparing an etch-resistant Ni hard mask layer. The above experiments demonstrate that, using the present method, we can obtain a Ni film that is free of columnar structures, dense, has a smooth surface, exhibits excellent corrosion resistance, has a high etch selectivity, and exhibits a fast deposition rate.

[0087] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an etching-resistant Ni hard mask layer, characterized in that: The following steps are involved: A Ni film was deposited on the substrate surface by magnetron sputtering; The magnetron sputtering method comprises the following steps: The pretreated substrate was placed on the anode in the vacuum chamber of the magnetron sputtering coating machine. 99.99% high-purity Ni was used as the target material, Ar gas was used as the sputtering gas, and H2 gas was used as the etching gas. Under vacuum conditions, the Ni target was sputtered to grow a Ni film. The vacuum condition is a vacuum degree of less than 8×10 -4 Pa; The substrate heating temperature is 100°C to 250°C; The sputtering pressure in the vacuum chamber is 0.15~0.5Pa; The Ar gas flow rate is 25-40 sccm, and the H2 gas flow rate is 2.5-5.6 sccm; The flow ratio of the Ar gas to the H2 gas is 7:1 to 10:1; The sputtering power is 100-250W.

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