Yellow light etching method

Abstract

The invention discloses a yellow light etching method, and belongs to the technical field of precision machining of ultrathin brittle materials. According to the scheme, firstly, the strong-alkali-resistant protective layer is prepared on the to-be-processed surface of the base material, then, the photoresist layer is prepared on the protective layer, the texture pattern is formed on the photoresist layer through the yellow light process, then, the protective layer exposed below the texture pattern is removed, the base material is subjected to first alkaline etching according to the texture pattern, and finally, all the protective layers are removed. And a precise texture pattern is obtained. According to the scheme, the strong-alkali-resistant protective layer is prepared between the base material and the photoresist layer, so that traditional acid liquor etching can be replaced by alkaline etching, the technical bottleneck of insufficient alkali resistance of the photoresist material in the traditional manufacturing process is solved, the application scene of the yellow light etching process is expanded, the etching precision and the product yield are improved, and the production cost is reduced. The consumption cost of chemicals is reduced, the discharge amount of the fluorine-containing acid waste liquid is reduced, the harm to personnel, equipment and environment is reduced, and the requirement of green manufacturing is met.

Description

Technical Field

[0001] The invention relates to the technical field of ultra-thin brittle material precision processing, in particular to a yellow light etching method. Background Art

[0002] In traditional photolithography processes, photoresist materials are widely used to define fine patterns and achieve the transfer of specific structures through steps such as exposure and development. Subsequently, an etching process is usually used to remove material from areas not covered by the photoresist to complete the final graphical processing. However, most current photolithography processes still rely mainly on acidic chemical liquids such as hydrofluoric acid for etching. This type of highly corrosive acidic liquid not only causes serious corrosion to the equipment, but also poses a great threat to the environment and the safety of operators, and the treatment and discharge process also requires a lot of costs. In addition, with the development of new processing needs, especially in alkaline liquid polishing or alkaline chemical etching environments, existing photoresist materials generally exhibit poor alkali resistance. In particular, in high-concentration alkaline solutions such as NaOH solutions, traditional photoresist layers are prone to swelling, dissolution, or even complete corrosion, causing the formed pattern to deform, fall off, or reduce resolution, thereby affecting subsequent processing accuracy and process stability. Summary of the Invention

[0003] The technical problem to be solved by the present invention is: in view of the above-mentioned defects of the prior art, a yellow light etching method with high processing precision and environmental friendliness is provided.

[0004] To achieve the above object, the technical solution adopted by the present invention is: providing a yellow light etching method, the method comprising the following steps:

[0005] Step S1, cleaning the surface of the substrate to ensure that the cleanliness of the surface to be processed of the substrate meets the process requirements;

[0006] Step S2, preparing a protective layer on the surface to be processed of the substrate, wherein the protective layer is made of a strong alkali-resistant material;

[0007] Step S3, coating a photoresist layer on the surface of the protective layer, and forming a texture pattern on the photoresist layer by a yellow light process; the photoresist layer is composed of a photoresist that is not resistant to strong alkali;

[0008] Step S4, using acid to remove the protective layer not covered by the photoresist layer;

[0009] Step S5, immersing the substrate in a first strong alkaline chemical solution, and performing a first alkaline etching on the substrate according to the texture pattern;

[0010] Step S6: using an acid solution to remove the protective layer exposed after the first alkaline etching.

[0011] In the yellow light etching method of the present invention, after step S6, the method further includes:

[0012] Step S7: immersing the substrate in a second strong alkaline chemical solution to perform a second alkaline etching on the substrate.

[0013] In the yellow light etching method of the present invention, in the step S2, the method for preparing the protective layer on the surface to be processed of the substrate is physical vapor deposition.

[0014] In the yellow light etching method of the present invention, the alkali-resistant material includes alkali-resistant metals and alkali-resistant metal oxides.

[0015] In the yellow light etching method of the present invention, in the step S2, the thickness of the protective layer is 20 nm to 1000 nm.

[0016] In the yellow light etching method of the present invention, forming a texture pattern on the photoresist layer by a yellow light process includes:

[0017] pre-curing the photoresist layer;

[0018] Expose and develop the photoresist layer in a pattern by a yellow light process;

[0019] The photoresist layer is finally cured.

[0020] In the yellow light etching method of the present invention, the concentration of the second strong alkaline chemical solution is higher than that of the first strong alkaline chemical solution, and the time of the second alkaline etching is longer than that of the first alkaline etching.

[0021] The present invention has the following beneficial effects: the solution of the present invention first prepares a strong alkali-resistant protective layer on the surface to be processed of the substrate, then prepares a photoresist layer on the protective layer, forms a texture pattern on the photoresist layer through a yellow light process, then removes the protective layer exposed under the texture pattern, and then performs a first alkaline etching on the substrate according to the texture pattern. During the first strong alkaline etching process, the photoresist layer is removed, exposing the remaining protective layer, and finally all the protective layers are removed to expose the substrate, thereby obtaining a precise texture pattern. The solution of the present invention prepares a strong alkali-resistant protective layer between the substrate and the photoresist layer, thereby allowing alkaline etching to replace traditional acid etching, solving the technical bottleneck of insufficient alkali resistance of photoresist materials in traditional processes, expanding the application scenarios of the yellow light etching process, improving etching accuracy and product yield, reducing chemical consumption costs, reducing the discharge of fluorine-containing acidic waste liquid, and reducing harm to personnel, equipment and the environment, thus meeting the requirements of green manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0023] Figure 1 Schematic diagram of the steps of the yellow light etching method according to an embodiment of the present invention.

[0024] Figure 2 This is a diagram showing the effect of the first alkaline etching of Example 1 of the present invention.

[0025] Figure 3 This is a diagram showing the effect of the second alkaline etching of Example 1 of the present invention.

[0026] Figure 4 Schematic diagram of line width deviation when a traditional acid etching process is used in Example 1 of the present invention.

[0027] Figure 5 Schematic diagram of line width deviation according to the first embodiment of the present invention.

[0028] Figure 6 Schematic diagram of etching sidewalls using a conventional acid etching process in accordance with the second embodiment of the present invention.

[0029] Figure 7 This is a schematic diagram of the etching sidewall according to the second embodiment of the present invention.

[0030] Figure 8 Schematic diagram of the surface roughness effect when the traditional acid etching process is adopted in the second embodiment of the present invention.

[0031] Figure 9 Schematic diagram of the surface roughness effect of the second embodiment of the present invention. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of 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. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0033] The embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings. It should be understood that the embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0034] The present invention is suitable for the precision processing of brittle materials such as glass, sapphire, and ceramics, and can meet the precision processing needs of high-end industries such as semiconductors, optical components, and display panels.

[0035] like Figure 1 As shown, an embodiment of the present invention provides a yellow light etching method, which includes the following steps:

[0036] Step S1 : cleaning the surface of the substrate to ensure that the cleanliness of the surface to be processed of the substrate meets the process requirements.

[0037] In the embodiments of the present invention, glass or other transparent, brittle materials are used as substrates and surface cleaning is performed to remove dirt and impurities, ensuring that the substrate surface is free of contaminants such as grease, dust, etc. During the cleaning process, ultrasonic cleaning can be performed using deionized water, isopropyl alcohol, or other detergents to ensure that the substrate surface cleanliness meets process requirements.

[0038] Step S2: preparing a protective layer on the surface of the substrate to be processed, wherein the protective layer is made of a material resistant to strong alkali.

[0039] In the embodiment of the present invention, in step S2, the alkali-resistant material includes alkali-resistant metals and alkali-resistant metal oxides, for example, alkali-resistant metal materials such as nickel, titanium, and chromium, and alkali-resistant metal oxides such as titanium oxide and chromium oxide.

[0040] The protective layer in the embodiments of the present invention has excellent chemical stability in a strongly alkaline environment, effectively resisting corrosion from strongly alkaline chemical solutions and maintaining integrity in a strongly alkaline environment. Therefore, it can effectively protect the substrate and prevent pattern deformation or failure, thereby improving process reliability and pattern accuracy. Therefore, the solution of this application can be applied to the yellow light process manufacturing of brittle materials such as glass, sapphire, and ceramics, meeting the precision machining needs of various high-end industries, and is particularly suitable for fields requiring high stability and high precision, such as semiconductor manufacturing, optical component processing, and display panel manufacturing.

[0041] In an embodiment of the present invention, in the step S2, the method for preparing a protective layer on the surface to be processed of the substrate is a physical vapor deposition method, specifically, including: magnetron sputtering and electron beam evaporation. The thickness of the protective layer is 20nm to 1000nm. By magnetron sputtering and electron evaporation, a dense protective layer film can be formed on the surface of the substrate, and at the same time, the thickness of the protective layer is controlled between 20nm and 1000nm, which can improve the bonding strength between the protective layer and the substrate and the photoresist layer, and ensure the strong alkali resistance of the protective layer. In an embodiment of the present invention, when preparing the protective layer by magnetron sputtering and electron evaporation, the deposition temperature is controlled at room temperature to 350°C, and the specific temperature is set in combination with the thermal stability of the substrate.

[0042] Step S3, coating a photoresist layer on the surface of the protective layer, and forming a texture pattern on the photoresist layer by a yellow light process; the photoresist layer is composed of a photoresist that is not resistant to strong alkali.

[0043] The photoresist layer in the prior art is generally not resistant to strong alkali. Therefore, in the embodiment of the present invention, a protective layer resistant to strong alkali corrosion is prepared between the photoresist layer and the substrate. The protective layer protects the substrate, so that alkaline etching can be used instead of acid etching.

[0044] In an embodiment of the present invention, in step S3, forming a texture pattern on the photoresist layer by a yellow light process includes:

[0045] pre-curing the photoresist layer;

[0046] Expose and develop the photoresist layer in a pattern by a yellow light process;

[0047] The photoresist layer is finally cured.

[0048] In embodiments of the present invention, a photoresist material is applied to the surface of the protective layer via spraying or slot coating techniques. The substrate coated with the photoresist material is then preheated and cured to enhance the stability and adhesion of the photoresist layer. In some embodiments of the present invention, the precuring temperature is 80°C to 100°C for 10 to 20 minutes. After precuring, a yellow light process is used to replicate the predetermined pattern onto the substrate surface. Specifically, the precured substrate can be placed in a yellow light exposure apparatus, where the photoresist layer is exposed using a mask tailored to the texture pattern. The unexposed photoresist layer is then removed by development to form the texture pattern. Finally, the unexposed portions of the photoresist are removed, leaving only the photoresist layer in the target pattern area. The photoresist layer is then subjected to a final curing step to enhance its hardness and durability. In some embodiments of the present invention, the final curing temperature is 150°C to 200°C for 30 to 50 minutes. Forming texture patterns on photoresist layers using a yellow light process is conventional technology. In practical applications, the relevant process can be adjusted according to specific needs, and this invention does not impose any particular limitations on this technology.

[0049] Step S4: using acid to remove the protective layer not covered by the photoresist layer.

[0050] In this embodiment of the present invention, after step S3, portions of the photoresist layer are dissolved by the developer, exposing the underlying protective layer. Acid is then used to remove this portion of the protective layer, exposing the substrate. After step S4, the photoresist layer and the protective layer cover the same area, leaving the exposed portion of the substrate where alkaline etching is intended.

[0051] In one embodiment of the present invention, sulfuric acid at a concentration of 1% to 2% is used to remove the portion of the protective layer not covered by the photoresist layer. In practical applications, the acid solution can be sprayed onto the exposed protective layer, where it reacts with the sulfuric acid to dissolve, forming a localized protective layer structure consistent with the pattern of the photoresist layer.

[0052] Step S5 , immersing the substrate in a first strong alkaline chemical solution, and performing a first alkaline etching on the substrate according to the texture pattern.

[0053] The composition, concentration, etching temperature, and etching time of the first strong alkaline chemical solution can be determined according to the material, thickness, and etching effect of the photoresist layer. In some embodiments of the present invention, the method of the first alkaline etching is as follows: immersing the substrate in a NaOH solution with a concentration of 30% to 50%, and the etching temperature is 100°C to 150°C, and performing the first alkaline chemical etching on the area not covered by the protective layer and the photoresist layer. The etching time is determined according to the specific application scenario. Because the protective layer is resistant to strong alkali corrosion, alkaline etching can be used instead of traditional acid etching, which helps to protect the safety of equipment and operators and promote the further development of green manufacturing.

[0054] If a deeper pattern needs to be etched and the area protected by the protective layer is not etched, step S5 can be repeated multiple times as needed, and then step S6 can be performed.

[0055] Step S6: using an acid solution to remove the protective layer exposed after the first alkaline etching.

[0056] Because the photoresist layer is not resistant to alkaline corrosion, after the first alkaline etching, the photoresist layer has been completely removed, exposing the protective layer under the photoresist layer. In an embodiment of the present invention, an acid solution such as phosphoric acid, citric acid, and acetic acid is used to remove the protective layer. Phosphoric acid has good solubility for metal oxides and has little impact on the environment. A concentration of 5% to 20% phosphoric acid can be selected, and the reaction temperature is 40°C to 80°C. Citric acid is an organic acid that is environmentally friendly and suitable for removing metal oxide layers. It causes less damage to the substrate. A concentration of 10% to 30% citric acid can be selected, and the reaction temperature is 50°C to 90°C. Acetic acid is a common mild acid solution that has a certain solubility for metal oxide layers and is suitable for local removal. A concentration of 20% to 50% acetic acid can be selected, and the reaction temperature is 50°C to 100°C.

[0057] After step S6, the protective layer is completely removed and the substrate is completely exposed. If a deeper pattern needs to be etched and the area protected by the protective layer is also etched, step S7 can be performed at least once after removing the protective layer.

[0058] Step S7: immersing the substrate in a second strong alkaline chemical solution to perform a second alkaline etching on the substrate.

[0059] In step S7, the substrate is immersed in the strong alkaline chemical liquid again to perform deeper etching on the area etched by the first alkaline etching. At the same time, the area protected by the protective layer on the surface to be processed of the substrate is also uniformly etched to meet the requirements of optical performance and appearance effect.

[0060] The first alkaline etching and the second alkaline etching can use strong alkaline chemical solutions of different concentrations, and the etching time can also be set according to the needs of the specific application. In some embodiments of the present invention, the concentration of the second strong alkaline chemical solution is higher than that of the first strong alkaline chemical solution, and the second alkaline etching time is longer than that of the first alkaline etching.

[0061] The composition, concentration, etching temperature, and etching time of the second strongly alkaline chemical solution can be determined based on the material and thickness of the protective layer, the material and thickness of the substrate, and the processing purpose. In some embodiments of the present invention, the second alkaline etching method comprises: immersing the substrate in a NaOH solution with a concentration of 40% to 80%, etching at a temperature of 100°C to 220°C, and performing a second alkaline chemical etching on the surface of the substrate to be processed. The etching time is determined based on the specific application scenario.

[0062] During the alkaline etching process, it is necessary to spray an alkaline corrosion-resistant protective agent on other surfaces of the substrate other than the surface to be processed to prevent other surfaces from being corroded by the strong alkaline chemical solution.

[0063] In the embodiment of the present invention, the step S7 further includes:

[0064] In step S8, the surface of the substrate is cleaned to remove the residual chemical liquid, and then the substrate is dried.

[0065] In the embodiment of the present invention, deionized water is used to clean the surface of the substrate to remove the chemical solution remaining on the surface of the substrate. After cleaning, the substrate is placed in a drying device for drying to ensure that there is no water stain on the surface of the substrate and the smoothness meets production requirements.

[0066] The solution of the present invention first prepares a strong alkali-resistant protective layer on the surface to be processed of the substrate, then prepares a photoresist layer on the protective layer, forms a texture pattern on the photoresist layer through a yellow light process, then removes the protective layer exposed under the texture pattern, and then performs a first alkaline etching on the substrate according to the texture pattern. During the first strong alkaline etching process, the photoresist layer is removed, exposing the remaining protective layer. Finally, all protective layers are removed to expose the substrate, thereby obtaining a precise texture pattern. The solution of the present invention prepares a strong alkali-resistant protective layer between the substrate and the photoresist layer, thereby allowing alkaline etching to replace traditional acid etching, solving the technical bottleneck of insufficient alkali resistance of photoresist materials in traditional processes, expanding the application scenarios of the yellow light etching process, improving etching accuracy and product yield, reducing chemical consumption costs, reducing the discharge of fluorine-containing acidic waste liquids, and reducing harm to personnel, equipment and the environment, thus meeting the requirements of green manufacturing.

[0067] Example 1

[0068] This embodiment is used for precision micro-hole processing of sapphire substrates, bases, and substrates in consumer electronic products such as watches. The main processing process is as follows:

[0069] Step S1: Clean the surface of the substrate to ensure that the cleanliness of the substrate to be processed meets the process requirements. The substrate used in this embodiment is a 1-8 inch sapphire sheet or silicon wafer, which can be square, round or other polygonal, with a thickness of 0.1mm to 2mm.

[0070] Step S2: Forming a protective layer on the surface of the substrate to be processed. The protective layer is made of a strong alkali-resistant material. In this embodiment, a titanium oxide protective layer with a thickness of 20 nm to 1000 nm is formed on the surface of the substrate to be processed by magnetron sputtering. The deposition temperature during magnetron sputtering is 150°C to 350°C, and 200°C is typically selected.

[0071] In step S3, a photoresist layer is coated on the surface of the protective layer, and a texture pattern is formed on the photoresist layer by a yellow light process; the photoresist layer is composed of a photoresist that is not resistant to strong alkali. In this embodiment, the photoresist used is a negative photoresist such as an epoxy resin-based photoresist.

[0072] Step S4: using acid to remove the portion of the protective layer not covered by the photoresist layer. In this embodiment, sulfuric acid with a concentration of 1% to 2% is used to remove the portion of the protective layer not covered by the photoresist layer.

[0073] Step S5, immersing the substrate in a first strong alkaline chemical solution, and performing a first alkaline etching on the substrate according to the texture pattern. In this embodiment, the first strong alkaline chemical solution is a NaOH solution with a concentration of 30% to 50%, the etching temperature is 100°C to 150°C, and the etching time is 30 minutes to 60 minutes. Figure 2The image shown is the effect after the first alkaline etching taken with an optical microscope, wherein the multiple circular areas are areas not covered by the protective layer and etched by the strong alkaline liquid, and the areas outside the circular areas are areas covered by the protective layer.

[0074] Step S6: using an acid solution to remove the protective layer exposed after the first alkaline etching. In this embodiment, phosphoric acid with a concentration of 5% to 50% and a temperature of 35° C. to 70° C. is used to remove the protective layer.

[0075] Step S7, immersing the substrate in a second strong alkaline chemical solution, and performing a second alkaline etching on the substrate. In this embodiment, the second strong alkaline chemical solution is a NaOH solution with a concentration of 50% to 80%, the etching temperature is 160°C to 220°C, and the etching time is 90 minutes to 120 minutes. Figure 3 The image shown is the effect after the second alkaline etching, which was taken under an optical microscope. The entire surface of the substrate is etched, and multiple circular areas are etched twice to form multiple microporous structures.

[0076] Step S8: cleaning the surface of the substrate to remove the residual chemical liquid, and then drying the substrate. In this embodiment, deionized water is used to clean the surface of the substrate.

[0077] The effect data of this embodiment are as follows:

[0078] (1) Target line width: 5μm±0.25μm. Figure 4 This is a schematic diagram of the line width deviation of the traditional acid etching process captured by an optical microscope. The measured line width deviation of the traditional acid etching process is ±0.5μm. Figure 5 The line width deviation diagram after adopting the solution of this embodiment is photographed by an optical microscope. The measured line width deviation is: ±0.2μm. Therefore, the accuracy of the alkaline etching solution of this embodiment is better than that of the traditional acid etching process.

[0079] (2) Yield: The yield of products produced by conventional acid etching processes is approximately 80%, while the yield of products produced by the solution of this embodiment is greater than 95%.

[0080] (3) Environmental protection and low cost: The solution of this embodiment completely avoids the use of HF, and the discharge of HF waste liquid is reduced by 100%. Since the strong alkaline liquid used for alkaline etching can be recycled, the chemical consumption cost is reduced by 40%.

[0081] Example 2

[0082] This embodiment is used for processing the micro-nano optical structure of the anti-glare glass cover in the display module of the electronic device. The main processing flow is as follows:

[0083] Step S1: Clean the surface of the substrate to ensure that the cleanliness of the surface to be processed meets the process requirements. The substrate used in this embodiment is optical glass such as soda-lime glass and lithium aluminum silicate glass, with a thickness of 0.2 mm to 2 mm.

[0084] Step S2: Preparing a protective layer on the surface of the substrate to be processed. The protective layer is made of a strong alkali-resistant material. In this embodiment, a chromium protective layer with a thickness of 20nm to 1000nm is prepared on the surface of the substrate to be processed by magnetron sputtering or electron beam evaporation, and the deposition temperature is room temperature to 250°C.

[0085] In step S3, a photoresist layer is coated on the surface of the protective layer, and a texture pattern is formed on the photoresist layer by a yellow light process; the photoresist layer is composed of a photoresist that is not resistant to strong alkali. In this embodiment, the photoresist used is a positive photoresist such as a polyimide-based photoresist.

[0086] Step S4: using acid to remove the portion of the protective layer not covered by the photoresist layer. In this embodiment, sulfuric acid with a concentration of 1% to 2% is used to remove the portion of the protective layer not covered by the photoresist layer.

[0087] In step S5, the substrate is immersed in a first strong alkaline chemical solution and the substrate is subjected to a first alkaline etching according to the texture pattern. In this embodiment, the first strong alkaline chemical solution is a NaOH solution with a concentration of 30% to 50%, the etching temperature is 100° C. to 150° C., and the etching time is 30 seconds to 5 minutes.

[0088] Step S6: using acid to remove the protective layer exposed after the first alkaline etching. In this embodiment, citric acid with a concentration of 5% to 50% and a temperature of room temperature to 100° C. is used to remove the protective layer.

[0089] In step S7, the substrate is immersed in a second strong alkaline chemical solution to perform a second alkaline etching on the substrate. In this embodiment, the second strong alkaline chemical solution is a NaOH solution with a concentration of 40% to 70%, the etching temperature is 100° C. to 150° C., and the etching time is 30 minutes to 180 minutes.

[0090] Step S8: cleaning the surface of the substrate to remove the residual chemical liquid, and then drying the substrate. In this embodiment, deionized water is used to clean the surface of the substrate.

[0091] The effect data of this embodiment are as follows:

[0092] (1) Surface quality: Figure 6 This is a schematic diagram of the etching sidewall of the traditional acid etching process taken with a scanning electron microscope. The tap angle of the etching sidewall corresponding to the traditional acid etching process is 75°±2°. Figure 7This is a schematic diagram of the etched sidewalls, captured under a scanning electron microscope, after using this embodiment. The tap angle of the etched sidewalls is 85°±2°. This approach to verticality maintains the original geometric dimensions and shape of the texture pattern, improving machining accuracy.

[0093] Figure 8 Schematic diagram of surface roughness of traditional acid etching process. The surface roughness of traditional acid etching process is Ra>20nm. Figure 9 The surface roughness diagram after adopting the scheme of this embodiment is shown in FIG. 1 , where the surface roughness Ra is less than 10 nm. Figure 8 and Figure 9 All are surface contour maps showing roughness, with different colors representing different heights.

[0094] (2) Environmental protection and low cost: The solution of this embodiment completely avoids the use of HF, and the discharge of HF waste liquid is reduced by 100%. Since the strong alkaline liquid used for alkaline etching can be recycled, the chemical consumption cost is reduced by 40%.

[0095] The above is only a specific embodiment of the present invention and cannot be used to limit the scope of the present invention. Equal changes made by ordinary technicians in this technical field based on this creation, as well as changes well known to technicians in this field, should still fall within the scope of the present invention.

Claims

1. A yellow light etching method, characterized in that, The method comprises the following steps: Step S1, cleaning the surface of the substrate to ensure that the cleanliness of the surface to be processed of the substrate meets the process requirements; Step S2, preparing a protective layer on the surface to be processed of the substrate, wherein the protective layer is made of a strong alkali-resistant material; Step S3, coating a photoresist layer on the surface of the protective layer, and forming a texture pattern on the photoresist layer by a yellow light process; the photoresist layer is composed of a photoresist that is not resistant to strong alkali; Step S4, using acid to remove the protective layer not covered by the photoresist layer; Step S5, immersing the substrate in a first strong alkaline chemical solution, and performing a first alkaline etching on the substrate according to the texture pattern; Step S6: using an acid solution to remove the protective layer exposed after the first alkaline etching.

2. The yellow light etching method according to claim 1, wherein After step S6, the method further includes: Step S7: immersing the substrate in a second strong alkaline chemical solution to perform a second alkaline etching on the substrate.

3. The yellow light etching method according to claim 1, wherein: In the step S2, the method for preparing the protective layer on the surface to be processed of the substrate is physical vapor deposition.

4. The yellow light etching method according to claim 1, wherein: In step S2, the alkali-resistant material includes alkali-resistant metals and alkali-resistant metal oxides.

5. The yellow light etching method according to claim 1, wherein: In the step S2, the thickness of the protective layer is 20 nm to 1000 nm.

6. The yellow light etching method according to claim 1, characterized in that: In step S3, forming a texture pattern on the photoresist layer by a yellow light process includes: pre-curing the photoresist layer; Expose and develop the photoresist layer in a pattern by a yellow light process; The photoresist layer is finally cured.

7. The yellow light etching method according to claim 2, characterized in that: The concentration of the second strong alkaline chemical solution is higher than that of the first strong alkaline chemical solution, and the time of the second alkaline etching is longer than that of the first alkaline etching.

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