An etching paste, its preparation method and application method

Abstract

The present application relates to the field of semiconductor devices, in particular to an etching paste and a preparation method and application method thereof. The etching paste comprises an acidic agent, clay, a water-retaining agent and solvent water, the water-retaining agent is obtained by homogenizing hydrogel, the hydrogel is prepared by cross-linking monomers and water, and the acidic agent is used to provide hydrogen ions. After the cross-linking monomers are prepared into hydrogel in water, a base paste prepared by the acidic agent, clay and solvent water is added, mixed and homogenized to obtain the etching paste. The etching paste is patterned and coated on the surface of a substrate to be etched to form an etching layer with a preset shape, and the etching layer is removed after heat treatment, thereby realizing efficient and precise etching of the substrate, reducing the costs of raw materials, process time and waste liquid treatment, and having high practicability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor devices, and in particular to an etching paste and its preparation and application methods. Background Technology

[0002] Indium tin oxide (ITO) is a transparent and conductive material with high mechanical hardness and good chemical stability, and is commonly used as a transparent electrode in semiconductor devices. When ITO films are used as electrodes in semiconductor devices, the surface of the ITO film often needs to be patterned by etching with etchant to form a current that conducts along the target direction. Currently, ITO layer etching is usually performed using dry etching. After cleaning the ITO layer surface, etchant is uniformly patterned and coated on the ITO layer surface. After drying through heat treatment, the etchant is removed. The etching of the ITO layer is achieved by the etching agent dissolving and corroding the ITO.

[0003] However, as heat treatment progresses, the solvent in the etching paste gradually evaporates, and the hydrogen ions in the etching paste gradually lose the environment for diffusion and reaction to dissolve ITO, leading to a rapid decline in etching capability and making it difficult to meet practical requirements. Increasing the content of etching components in the etching paste or increasing the amount of etching paste used can improve etching efficiency and thus the final etching effect, but it also leads to an increase in by-products such as wastewater and waste liquid, resulting in a significant increase in waste liquid treatment costs. Increasing ambient humidity to suppress solvent evaporation has high environmental requirements, increases operating costs, and may cause defects at the edges of the etchant, reducing etching precision. Therefore, all of the above methods lead to an increase in etching costs. Summary of the Invention

[0004] The purpose of this invention is to provide an etching paste with low cost and good etching effect, as well as its preparation method and application method.

[0005] To achieve the above objectives, the present invention provides the following technical solution: In a first aspect, the present invention provides an etching paste comprising an acidic agent, clay, a water-retaining agent, and a solvent water, wherein the water-retaining agent is obtained by homogenizing a hydrogel, the hydrogel is prepared by crosslinking monomers and water, and the acidic agent is used to provide hydrogen ions.

[0006] Optionally, the crosslinking monomer includes one or more of chitosan, cellulose and its derivatives, alginate, agarose, gelatin, collagen, polyacrylic acid and its derivatives, polyacrylamide, polyvinyl alcohol, polyethylene glycol and its derivatives, polyethylene oxide, polyethylene oxide, and poly(N-isopropylacrylamide), the water-retaining agent is any value between 5% and 60% of the etching paste, and the total mass fraction of water contained in the etching paste is any value between 1% and 40%.

[0007] Optionally, the acidic agent includes one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, and oxalic acid, and the mass of the acidic agent is any value from 0.1% to 20% of the etching paste.

[0008] Optionally, the clay includes one or more of silica, kaolin, and montmorillonite, the mass of the clay is any value between 5% and 20% of the etching paste, and the average particle size of the clay is any value between 0.1 μm and 10 μm.

[0009] Optionally, the etching paste further includes: A thickener, comprising one or more of polyvinylpyrrolidone, polyvinyl alcohol, and polyethylene glycol, wherein the mass of the thickener is any value between 10% and 30% of the etching paste; The wetting agent includes one or more of ethylene glycol, propylene glycol, and glycerol, and the mass of the wetting agent is any value from 0.2% to 5% of the etching paste; The surfactant comprises one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl sulfonate, and oxyethylene ether-oxypropylene ether block polyether, wherein the mass of the surfactant is any value from 0.2% to 5% of the etching paste.

[0010] Optionally, the etching paste further includes an oxidizing agent, which includes one or more of hydrogen peroxide, ferric chloride, ferric nitrate, cerium ammonium nitrate, sodium persulfate, ammonium persulfate, and potassium persulfate. The mass of the oxidizing agent is any value from 0.1% to 10% of the etching paste. The etching paste is used for etching metal oxides and / or metal materials. The metal oxide is a transparent conductive material, and its composition includes one or more of indium tin oxide, calcium titanium oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, zinc-doped indium oxide, and hydrogen-doped indium oxide. The composition of the metal material includes one or more of elemental copper, elemental titanium, elemental aluminum, elemental iron, elemental tungsten, and elemental magnesium.

[0011] Secondly, the present invention also provides a method for preparing the above-mentioned etching paste, comprising: The crosslinking monomer is crosslinked and cured in water to obtain the hydrogel; The acidic agent, the clay, and the solvent water are formulated into a base paste; The base paste and the hydrogel are mixed and homogenized to obtain the etching paste.

[0012] Thirdly, the present invention also provides a method for applying the above-mentioned etching paste, comprising: The etching paste is applied to the surface of the substrate to be etched to form an etching layer, the shape of which is matched to the target pattern to be etched; The substrate on which the etched layer is formed is heat-treated at a first temperature for a first time; Remove the etched layer after heat treatment to form an etched pattern on the substrate surface that conforms to the target pattern.

[0013] Optionally, the composition of the metallic material includes one or more of elemental copper, elemental titanium, elemental aluminum, elemental iron, elemental tungsten, and elemental magnesium.

[0014] Optionally, the etching paste is used to form the etching layer by screen printing or scraping, and the line accuracy of the etched pattern is any value from 1μm to 1000mm.

[0015] According to a first aspect of the invention, an acidic agent provides hydrogen ions to dissolve the substrate to be etched, and clay is used as a filler to shape the acidic agent, allowing the etching paste to be coated onto the substrate surface in a predetermined shape, thereby achieving patterned etching. The crosslinking monomer is a hydrophilic polymer, and the water-retaining agent is obtained by homogenizing a hydrogel formed by the swelling of the crosslinking monomer in water. The hydrophilic groups between multiple crosslinking monomer molecules interact with water molecules, causing the polymer chains to swell, thus achieving water retention. During dissolution etching after patterned coating of the etching paste, the binding force between the water-retaining agent and water molecules inhibits the evaporation of water molecules, thereby maintaining the wettability of the etching paste and enabling the acidic agent to continuously provide hydrogen ions to corrode the substrate, which helps to improve the etching effect of the etching paste.

[0016] According to a second aspect of the invention, the crosslinking monomer swells in water to form a hydrogel. In this process, the crosslinking monomer crosslinks to form a three-dimensional hydrophilic network. Water molecules are confined within the voids of the three-dimensional hydrophilic network by the hydrophilic groups within the network. The hydrogel is then mixed with a prepared base paste to form a homogenate, ensuring thorough mixing. Under mechanical force, the three-dimensional hydrophilic network breaks down, forming a water-retaining agent that is relatively stably bonded to the water molecules. This allows the etching paste to maintain a higher water content while retaining low fluidity, and also prevents some water molecules from evaporating easily, enabling the etching paste to maintain a state of low fluidity but high wettability for a longer period.

[0017] According to a third aspect of the invention, an etching paste with strong water-retention properties is used for etching. During the heat treatment process, while accelerating the efficiency of the chemical reaction between the acid agent and the substrate, the free water in the substrate paste evaporates rapidly, causing the fluidity of the etching paste to decrease rapidly. The etched layer shape solidifies quickly and adheres tightly to the substrate surface. The bound water of the water-retention agent is slowly released and evaporated under the constraint of the cross-linked monomers, providing a reaction environment for the reaction between the acid agent and the substrate, thereby reducing the reaction time, completing the etching quickly, and achieving a better etching effect.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a flowchart of the preparation method of the etching paste shown in Embodiment 1 of the present invention; Figure 2 This is a flowchart illustrating the application method of the etching paste shown in Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the target graphic shown in Embodiment 1 of the present invention. Detailed Implementation

[0020] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0023] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] This invention application protects an etching paste comprising an acidic agent, clay, a water-retaining agent, and a solvent, wherein the water-retaining agent is obtained by homogenizing a hydrogel, the hydrogel is prepared by crosslinking monomers and water, and the acidic agent is used to provide hydrogen ions.

[0025] The etching paste is dissolved by hydrogen ions provided by an acidic agent, and clay is used as a filler to shape the acidic agent, allowing it to be coated onto the substrate surface in a predetermined shape for patterned etching. The crosslinking monomers are hydrophilic polymers, and the water-retaining agent is obtained by homogenizing a hydrogel formed by the swelling of the crosslinking monomers in water. The hydrophilic groups between multiple crosslinking monomer molecules interact with water molecules, causing the polymer chains to swell, thus achieving water retention. During the dissolution etching process after the patterned etching paste is applied, the binding force between the water-retaining agent and water molecules inhibits the evaporation of water molecules, thereby maintaining the wettability of the etching paste. This allows the acidic agent to continuously provide hydrogen ions to corrode the substrate, contributing to improved etching performance.

[0026] In some embodiments, the crosslinking monomers include one or more of chitosan, cellulose and its derivatives, alginate, agarose, gelatin, collagen, polyacrylic acid and its derivatives, polyacrylamide, polyvinyl alcohol, polyethylene glycol and its derivatives, polyethylene oxide, polyethylene oxide, and poly(N-isopropylacrylamide). The water-retaining agent is any value from 5% to 60% of the etching paste, for example, any value from 5%, 7%, 9%, 10%, 12%, 15%, 17%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, and 60%, adjusted according to the water absorption of different crosslinking monomers. If the crosslinking monomer content is relatively low, problems such as decreased etching ability may occur. If the crosslinking monomer content is relatively high, problems such as difficulty in forming a paste, poor printability, or collapse of printed lines may occur. The total water content in the etching paste should be any value between 1% and 40% by mass, for example, any value from 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, and 40%. This helps in the shaping of the etching paste and the full dissolution of hydrogen ions from the acidic agent. If the total water content is relatively low, problems such as incomplete dissolution of materials and clumping of the etching paste may occur. If the total water content is relatively high, problems such as difficulty in forming a paste, poor printability, or collapse of printed lines may occur.

[0027] In some embodiments, the acidic agent includes one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid, and oxalic acid. The mass of the acidic agent is any value from 0.1% to 20% of the etching paste, for example, any value from 0.1%, 0.5%, 1%, 3%, 5%, 7%, 9%, 10%, 15%, and 20%, which helps to ensure the etching paste's corrosive and dissolving capabilities. The type and content of the acidic agent in the etching paste can be selected and adjusted according to the material of the substrate to be etched and the etching requirements of the actual application scenario. Too low an acidic agent content will lead to etching performance deviation; too high an acidic agent content will lead to over-etching and generate more wastewater and waste liquid.

[0028] In some embodiments, the clay includes one or more of silica, kaolin, and montmorillonite. The mass of the clay is any value from 5% to 20% of the etching paste, for example, any value from 5%, 15%, and 20%. The average particle size of the clay is any value from 0.1 μm to 10 μm, for example, any value from 0.1 μm, 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm. Controlling the clay content helps ensure the mechanical strength, consistency, and spreadability of the etching paste. If the clay content is relatively low, there may be problems such as poor stability of the etching paste and difficulty in forming a paste. If the clay content is relatively high, there may be problems such as poor printability due to more solids and easy agglomeration. If the average particle size of the clay is small, there may be problems such as difficulty in forming a paste and easy collapse of the paste. If the average particle size of the clay is large, there may be problems such as poor printability and low etching precision due to large solid particle size.

[0029] In some embodiments, the etching paste further includes: Thickener, including one or more of polyvinylpyrrolidone, polyvinyl alcohol and polyethylene glycol, the mass of the thickener being any value from 10% to 30% of the etching paste, for example, any value from 10%, 12%, 14%, 16%, 18%, 20%, 22%, 24%, 26%, 28% and 30%. The wetting agent includes one or more of ethylene glycol, propylene glycol, and glycerol, and the mass of the wetting agent is any value from 0.2% to 5% of the etching paste, for example, any value from 0.2%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 2.8%, 3.0%, 3.5%, 4.0%, 4.1%, 4.5%, and 5%. The surfactant includes one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl sulfonate, and oxyethylene ether-oxypropylene ether block polyether. The surfactant is present in any value from 0.2% to 5% of the etching paste, for example, any value from 0.2%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 2.8%, 3.0%, 3.5%, 4.0%, 4.1%, 4.5%, and 5%.

[0030] Clay possesses a favorable layered structure, forming a physical network within the paste. This enhances the mechanical strength of the etching paste, improves its consistency and stability, and increases its adhesion, allowing for more uniform application to the substrate surface. However, the viscosity increase provided by clay is typically limited. It primarily improves the paste's consistency by increasing particle concentration and interparticle interactions, which is sometimes insufficient to fully control the rheology and workability of the etching paste. Adding thickeners allows for further regulation of the etching paste's rheology and workability through intermolecular interactions, improving consistency stability and adhesion, ensuring uniform adhesion, and inhibiting stratification after prolonged storage. The synergistic effect of thickeners and clay helps optimize the etching process, making it more precise and controllable.

[0031] Adding a wetting agent to the etching paste can significantly improve the contact and adhesion between the etching paste and the substrate surface. By reducing surface tension, the wetting agent enhances the wettability of the etching paste on the substrate surface, ensuring its uniform coverage and penetration into complex surfaces or micropores, thereby improving coating uniformity and etching effect. Furthermore, the wetting agent can reduce bubble formation, improve the dispersibility of the etching paste, enhance the stability and efficiency of the etching process, and prevent uneven etching or errors caused by uneven surface coating.

[0032] Adding surfactants to etching pastes can improve their wetting and spreading properties on the substrate surface by reducing the surface tension of the paste, promoting better contact between the paste and the substrate surface, ensuring uniform and firm adhesion of the coating, and improving flowability and coverage during the coating process. Surfactants also effectively stabilize the dispersion of raw material particles during preparation, preventing particle agglomeration or sedimentation, thereby ensuring the uniformity and precision of the etching reaction. Furthermore, surfactants help reduce pinholes and edge defects, improve the stability of the etching paste, and optimize the etching effect, which is particularly important when processing complex surfaces or microstructures. Surfactants also facilitate the cleaning of the etching paste after etching.

[0033] In some embodiments, the etching paste further includes an oxidant, which includes one or more of hydrogen peroxide, ferric chloride, ferric nitrate, cerium ammonium nitrate, sodium persulfate, ammonium persulfate, and potassium persulfate. The mass of the oxidant is any value from 0.1% to 10% of the etching paste, for example, any value from 0.1%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 6.0%, 7.0%, 8.0%, 9.0%, and 10%. The etching paste is used for etching metal oxides and / or metal materials. The metal oxide is a transparent conductive material, and its components include one or more of indium tin oxide, calcium titanium oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, zinc-doped indium oxide, and hydrogen-doped indium oxide. The metal material components include one or more of elemental copper, elemental titanium, elemental aluminum, elemental iron, elemental tungsten, and elemental magnesium.

[0034] Adding oxidants to etching paste enhances the rate and intensity of the oxidation reaction, thereby promoting the etching process of metal substrates. Oxidants effectively promote the dissolution of metal oxides such as SnO2 and In2O3, thus improving the etching efficiency of ITO. They can also oxidize metal materials before etching, achieving the etching of metal materials. Furthermore, they help remove oxide layers or contaminants from metal surfaces, ensuring that the metal is removed uniformly and rapidly during the etching process. The hydrogen ions provided by acidic agents have a good dissolution and corrosion effect on indium tin oxide and aluminum-doped zinc oxide materials. With the assistance of oxidants, acidic agents can also achieve the etching of metal materials.

[0035] Secondly, this invention also claims protection for a method for preparing the above-mentioned etching paste, comprising: S110: Crosslinking monomers are cured in a partially aqueous solvent to obtain a hydrogel.

[0036] S120. Prepare a base paste by mixing the acidic agent, clay, and remaining solvent water.

[0037] S130. Mix the base paste and hydrogel into a homogenate to obtain the etching paste.

[0038] The cross-linking monomer swells in water to form a hydrogel. At this point, the cross-linking monomer forms a three-dimensional hydrophilic network. Water molecules are confined within the voids of this network by the hydrophilic groups. The hydrogel is then mixed thoroughly with the prepared base paste. Under mechanical force, the three-dimensional hydrophilic network breaks down, forming a water-retaining agent that is relatively stable with the water molecules. This allows the etching paste to maintain a high water content while retaining low fluidity, and also prevents some water molecules from evaporating easily, enabling the etching paste to maintain a low fluidity but high wettability for a longer period.

[0039] It should be noted that this invention does not impose specific requirements or limitations on the molecular weight of the crosslinking monomers used to form the hydrogel. Furthermore, this invention does not impose specific requirements or limitations on the specific methods and processes for synthesizing the hydrogel.

[0040] Thirdly, this invention also claims protection for a method of applying the above-mentioned etching paste, comprising: S210. Apply etching paste to the surface of the substrate to be etched to form an etching layer. The shape of the etching layer is matched with the target pattern to be etched.

[0041] S220, heat-treat the substrate with the etched layer at a first temperature for a first time.

[0042] S230: Remove the etched layer after heat treatment and form an etched pattern on the substrate surface that matches the target pattern.

[0043] Etching is performed using an etching paste with strong water-retention properties. During heat treatment, the efficiency of the chemical reaction between the acid agent and the substrate is accelerated, while the free water in the substrate paste evaporates rapidly. This quickly reduces the fluidity of the etching paste, causing the etched layer shape to solidify rapidly and adhere tightly to the substrate surface. The bound water in the water-retention agent is slowly released and evaporated under the constraint of the cross-linked monomers, providing a reaction environment for the reaction between the acid agent and the substrate. This reduces the reaction time, completes the etching quickly, and achieves good etching results.

[0044] The etching paste in this invention can be used to etch ITO layers to form circuits, and also to etch excess ITO and metal materials at the edges of semiconductor devices. Excess ITO and metal materials refer to thin films of a certain thickness formed on non-coated surfaces. For example, during the PVD deposition of ITO and copper in heterojunction solar cells (HJTs), unwanted ITO and copper will inevitably be deposited at the edges of the cell panel. This can lead to leakage risks when using electroplated copper for patterned circuits in HJTs. In this case, an etching layer needs to be applied according to the formation of excess ITO and metal materials for etching.

[0045] In some embodiments, the first temperature is any value from 50°C to 150°C, for example, any value from 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, and 150°C; and the first time is any value from 5 min to 60 min, for example, any value from 5 min, 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, and 60 min. If the drying temperature is too low, the etching efficiency may decrease; if the drying temperature is too high, some material may volatilize or decompose, affecting the etching paste effect. If the drying time is too short, the etching may be incomplete; if the drying time is too long, the process time and cost may increase.

[0046] In some embodiments, the etching paste is used to form an etching layer by screen printing or scraping. The line accuracy of the etched pattern is any value from 1μm to 1000mm, for example, any value from 1μm, 10μm, 30μm, 50μm, 100μm, 150μm, 300μm, 500μm, 1mm, 10mm, 50mm, 100mm, 500mm and 1000mm. The screen printing or scraping method helps to coat the etching paste evenly and accurately, thereby achieving uniform patterned etching.

[0047] Please refer to the following examples for details.

[0048] Example 1: Please see Figure 1 The method for preparing the etching paste shown in a preferred embodiment of this application includes: S110: Crosslink the crosslinking monomers in water to solidify them and obtain a hydrogel.

[0049] S120. Prepare a base paste by mixing an acidic agent, clay, and solvent water.

[0050] S130. Mix the base paste and hydrogel into a homogenate to obtain the etching paste.

[0051] Step S110 includes: S111. Weigh sodium alginate and calcium chloride separately and add them to pure water. Stir to dissolve, obtaining a 4% sodium alginate solution and a 3% calcium chloride aqueous solution, with a molar ratio of sodium alginate to calcium chloride of approximately 2.1:1. All percentage concentrations in this invention are mass fractions.

[0052] S112. Add calcium chloride aqueous solution dropwise to sodium alginate solution to crosslink the carboxyl groups in sodium alginate with calcium ions. After standing for 30 minutes, rinse with pure water to remove excess ions and obtain hydrogel.

[0053] In step S120, the acidic agent is sulfuric acid, the clay is silica with an average particle size of about 0.3 μm, polyvinylpyrrolidone is added as a thickener, ethylene glycol is added as a wetting agent, and no surfactant or oxidant is added. The above components are added to the solvent water in sequence and dispersed thoroughly. Finally, the clay is added, followed by the hydrogel obtained in step S110. After mixing, the mixture is homogenized to obtain the etching paste.

[0054] After homogenization, the hydrogel forms a water-retaining agent dispersed in the etching paste. In the etching paste obtained in this embodiment, the mass percentage of sulfuric acid is 5%, the mass percentage of silica is 15%, the mass percentage of water-retaining agent is 35%, the mass percentage of polyvinylpyrrolidone is 30%, the mass percentage of ethylene glycol is 5%, and the balance is pure water.

[0055] Please see Figure 2 The obtained etching paste is used to etch circuits on the ITO surface. The application methods include: S210. Apply etching paste to the surface of the substrate to be etched to form an etching layer. The shape of the etching layer is matched with the target pattern to be etched.

[0056] S220, heat-treat the substrate with the etched layer at a first temperature for a first time.

[0057] S230: Remove the etched layer after heat treatment and form an etched pattern on the substrate surface that matches the target pattern.

[0058] Please refer to the target graphic in step S210. Figure 3 In this embodiment, the substrate is a semiconductor device with a smooth ITO layer covering its surface, and the film layer adjacent to the ITO layer is made of insulating material. The target pattern includes multiple pattern units of the same shape, and the preset line precision of each pattern unit is 10μm, 50μm, 100μm, 300μm, 500μm and 1000μm, respectively, which are printed on the surface of the ITO layer by screen printing.

[0059] The first temperature in step S220 is 120℃, and the first time is 20min.

[0060] In step S230, the etched layer is removed by rinsing with pure water.

[0061] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0062] Example 2: The differences between this embodiment and Embodiment 1 are as follows.

[0063] Step S110 of this embodiment includes: weighing gelatin completely dissolved in pure water at 60°C to obtain a 20% gelatin solution, cooling it to room temperature to obtain a hydrogel.

[0064] In step S120 of this embodiment, the acidic agent includes oxalic acid and nitric acid, the clay is silica with an average particle size of about 0.3 μm, polyvinyl alcohol is added as a thickener, propylene glycol is added as a wetting agent, and no surfactant or oxidant is added.

[0065] In the etching paste obtained in this embodiment, the mass percentage of oxalic acid is 1%, the mass percentage of nitric acid is 2%, the mass percentage of silica is 20%, the mass percentage of water-retaining agent is 40%, the mass percentage of polyvinyl alcohol is 22%, the mass percentage of propylene glycol is 3%, and the balance is pure water.

[0066] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0067] Example 3: The differences between this embodiment and Embodiment 1 are as follows.

[0068] Step S110 of this embodiment includes: dissolving acetic acid and chitosan in pure water to make the concentration of acetic acid 1% and the concentration of chitosan 4%. Under ice-water bath conditions, dissolving sodium β-glycerophosphate to a final concentration of 10% in the solution, and then heating to 40°C to obtain a hydrogel.

[0069] In step S120 of this embodiment, the acidic agent is hydrochloric acid, the clay is kaolin with an average particle size of about 0.3 μm, polyvinylpyrrolidone is added as a thickener, glycerol is added as a wetting agent, sodium dodecyl sulfonate is added as a surfactant, and no oxidizing agent is added.

[0070] In the etching paste obtained in this embodiment, hydrochloric acid accounts for 13% by mass, kaolin accounts for 15% by mass, water-retaining agent accounts for 20% by mass, polyvinylpyrrolidone accounts for 27% by mass, glycerol accounts for 5% by mass, sodium dodecyl sulfonate accounts for 0.5% by mass, and the remainder is pure water.

[0071] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0072] Example 4: The differences between this embodiment and Embodiment 1 are as follows.

[0073] Step S110 of this embodiment includes: dissolving acrylamide in pure water, adding N,N'-methylenebisacrylamide, continuously purging nitrogen gas into the solution for 15 minutes, and then adding ammonium persulfate and tetramethylethylenediamine. The final solution contains 15% acrylamide, 0.5% N,N'-methylenebisacrylamide, 0.3% ammonium persulfate, and 0.05% tetramethylethylenediamine by mass. After stirring thoroughly, the solution is allowed to stand at room temperature for 30 minutes, washed three times with water to remove unreacted monomers, and a hydrogel is obtained.

[0074] In step S120 of this embodiment, the acidic agent is nitric acid, the clay is montmorillonite with an average particle size of about 0.3 μm, polyethylene glycol is added as a thickener, ethylene glycol is added as a wetting agent, and no surfactant or oxidant is added.

[0075] In the etching paste obtained in this embodiment, the mass percentage of nitric acid is 8%, the mass percentage of montmorillonite is 5%, the mass percentage of water-retaining agent is 40%, the mass percentage of polyethylene glycol is 10%, the mass percentage of ethylene glycol is 0.5%, and the balance is pure water.

[0076] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0077] Example 5: The only difference between this embodiment and Embodiment 1 is that in step S120 of this embodiment, no surfactant is added, but ferric chloride is added as an oxidant. Furthermore, the ferric chloride content in the etching paste obtained in this embodiment is 3% by mass.

[0078] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0079] Example 6: The only difference between this embodiment and Embodiment Two is that in step S120 of this embodiment, no surfactant is added, but hydrogen peroxide is added as an oxidant. Furthermore, the mass percentage of hydrogen peroxide in the etching paste obtained in this embodiment is 1%.

[0080] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0081] Example 7: The only difference between this embodiment and Embodiment 3 is that in step S120 of this embodiment, no surfactant is added, but sodium persulfate is added as an oxidant. Furthermore, the mass percentage of sodium persulfate in the etching paste obtained in this embodiment is 5%.

[0082] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0083] Example 8: The only difference between this embodiment and Embodiment 1 is that the mass percentage of sulfuric acid in the etching paste obtained in this embodiment is 2%.

[0084] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0085] Example 9: The only difference between this embodiment and Embodiment 1 is that the sulfuric acid content in the etching paste obtained in this embodiment is 8%.

[0086] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0087] Example 10: The only difference between this embodiment and Embodiment 1 is that the mass percentage of silicon dioxide in the etching paste obtained in this embodiment is 10%.

[0088] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0089] Example 11: The only difference between this embodiment and Embodiment 1 is that the mass percentage of silicon dioxide in the etching paste obtained in this embodiment is 20%.

[0090] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0091] Example 12: The only difference between this embodiment and Embodiment 1 is that the water-retaining agent accounts for 30% of the mass of the etching paste obtained in this embodiment.

[0092] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0093] Example 13: The only difference between this embodiment and Embodiment 1 is that the water-retaining agent accounts for 40% of the mass of the etching paste obtained in this embodiment.

[0094] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0095] Example 14: The only difference between this embodiment and Embodiment 1 is that the mass percentage of ethylene glycol in the etching paste obtained in this embodiment is 1%.

[0096] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0097] Example 15: The only difference between this embodiment and Embodiment 1 is that the ferric chloride content in the etching paste obtained in this embodiment is 1% by mass.

[0098] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0099] Example 16: The only difference between this embodiment and Embodiment 1 is that the ferric chloride content in the etching paste obtained in this embodiment is 7%.

[0100] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0101] Comparative Example 1: The only difference between this comparative example and Example 1 is that step S110 is not included in this comparative example, and hydrogel is not added in step S130.

[0102] After etching, the resulting etched pattern exhibits blurred lines and edges, with some line breaks and varying etching depths in certain areas. The actual line accuracy of each pattern unit was measured and found to differ significantly from the preset value. Comparison with the etched pattern in Example 1 demonstrates that adding some water via hydrogel to the etching paste effectively reduces its fluidity.

[0103] Comparative Example 2: The only difference between this comparative example and Example 5 is that step S110 is not included in this comparative example, and hydrogel is not added in step S130.

[0104] After etching, the resulting etched pattern exhibits blurred lines and edges, with some line breaks and varying etching depths in certain areas. The actual line accuracy of each pattern unit was measured and found to differ significantly from the preset values.

[0105] Comparative Example 3: The only difference between this comparative example and Example 1 is that the base paste obtained in step S120 is used as the etching paste in this comparative example.

[0106] After etching, the etched pattern is not significantly different from the target pattern, and the edges are relatively smooth. The actual circuit accuracy of each pattern unit is tested. The preset value has a slight deviation, but the deviation is small.

[0107] Comparative Example 4: The only difference between this comparative example and Comparative Example 3 is that the ambient humidity was maintained at 80% during the heat treatment in this comparative example.

[0108] After etching, the resulting etched pattern has no significant difference in shape from the target pattern, and the edges are smooth. The actual circuit accuracy of each pattern unit is tested and is similar to the preset value.

[0109] Example 17: The etching paste obtained in the various embodiments and comparative examples was used to etch lines onto the ITO surface. The target pattern was a continuous line with two endpoints. The same etching paste was used to etch the target patterns with different preset line precisions, and the unetched substrate was set as a blank group. A digital display probe multimeter with a maximum range of 20MΩ was connected to the two endpoints of each etched pattern, and its resistance was measured. Three sets of measurements were taken in parallel for each etched pattern, and the average value was used as the measurement value. The test results are shown in Table 1 below.

[0110] The experimental methods in each embodiment and comparative example are analyzed in conjunction with the data in Table 1. A comparison of the etching effects of the etching pastes in Embodiment 1 and Embodiment 5 shows that an oxidant is not necessary when etching the ITO surface. A comparison of the etching effects of the etching pastes in Embodiment 1, Embodiment 5, Comparative Example 1, and Comparative Example 2 shows that the addition of hydrogel material in this invention can increase the resistance inside and outside the pattern unit, indicating that adding hydrogel can effectively improve the etching effect and efficiency, ensuring complete etching of the ITO layer. A comparison of the etching effects of the etching pastes in Embodiment 1, Comparative Example 1, Comparative Example 3, and Comparative Example 4 shows that adding a water-retaining agent can effectively increase the water content in the paste while maintaining its low fluidity. It also allows the etching paste to maintain high humidity during heat treatment, thereby effectively improving etching efficiency, reducing the minimum linewidth, achieving efficient etching with an acidic agent that causes less environmental damage and is easier to treat, and reducing raw material costs and waste treatment costs. By comparing Examples 1 and Examples 8 to 16, it can be seen that adjusting the content of acidic agent, clay, water-retaining agent and other additives can completely etch the ITO layer.

[0111] Example 18: The etching pastes prepared in Examples 1, 5, 6, 7, 15, 16, and Comparative Example 2 were used to etch the edge coating of the solar cell. In step S210 of this example, the side edge of the solar cell was used as a substrate, and the target pattern was matched to the shape of excess ITO and copper to remove the excess ITO and copper. After etching, the resistance between the edges of the solar cell was measured at 1 cm intervals. Three sets of parallel measurements were taken, and the average value was used as the measurement value. The measurement results are shown in Table 2 below.

[0112] The experimental methods in each embodiment and comparative example were analyzed in conjunction with the data in Table 1. A comparison of Example 1 and Example 5 shows that an oxidant is essential when the etching paste of the present invention is used to etch metal materials. A comparison of Example 5 and Comparative Example 2 shows that adding hydrogel material can increase the resistance of the edge side of the semiconductor device, indicating that adding hydrogel can effectively improve the etching effect and efficiency, ensuring complete etching of the metal material and ITO. A comparison of Example 5 and Examples 6, 7, 15, and 16 shows that adjusting the content of acidic agent, clay, water-retaining agent, and other additives can completely etch the metal material and ITO.

[0113] As can be seen from the above embodiments and comparative examples, the novel etching paste described in this application has the advantages of being easy to prepare, having a good etching effect when dried at high temperature, having high precision in etched lines, high versatility, being easy to clean, being environmentally friendly, and having low cost.

[0114] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An etching paste, characterized in that, It includes an acidic agent, clay, a water-retaining agent, and a solvent, water, wherein the water-retaining agent is obtained by homogenizing a hydrogel, and the acidic agent is used to provide hydrogen ions; The method for preparing the etching paste includes: The hydrogel is obtained by crosslinking and curing an aqueous solution containing crosslinking monomers; The acidic agent, the clay, and the solvent water are formulated into a base paste; The base paste and the hydrogel are mixed and homogenized to obtain the etching paste; The crosslinking monomer includes one or more of chitosan, alginate, gelatin and acrylamide, the water-retaining agent has a mass of any value between 5% and 60% of the etching paste, and the total mass fraction of water contained in the etching paste has a mass of any value between 1% and 40%. The acidic agent includes one or more of sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid, acetic acid and oxalic acid, and the mass of the acidic agent is any value from 0.1% to 20% of the etching paste; The clay includes one or more of silica, kaolin, and montmorillonite, the mass of the clay is any value between 5% and 20% of the etching paste, and the average particle size of the clay is any value between 0.1 μm and 10 μm.

2. The etching paste as described in claim 1, characterized in that, Also includes: A thickener, the thickener comprising one or more of polyvinylpyrrolidone, polyvinyl alcohol and polyethylene glycol, wherein the mass of the thickener is any value between 10% and 30% of the etching paste; The wetting agent includes one or more of ethylene glycol, propylene glycol, and glycerol, and the mass of the wetting agent is any value from 0.2% to 5% of the etching paste; The surfactant comprises one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecyl sulfonate, and oxyethylene ether-oxypropylene ether block polyether, wherein the mass of the surfactant is any value from 0.2% to 5% of the etching paste.

3. The etching paste as described in claim 2, characterized in that, It also includes an oxidizing agent, which includes one or more of hydrogen peroxide, ferric chloride, ferric nitrate, cerium ammonium nitrate, sodium persulfate, ammonium persulfate, and potassium persulfate. The mass of the oxidizing agent is any value from 0.1% to 10% of the etching paste. The etching paste is used for etching metal oxides and / or metal materials. The metal oxide is a transparent conductive material, and its composition includes one or more of indium tin oxide, calcium titanium oxide, fluorine-doped tin oxide, aluminum-doped zinc oxide, zinc-doped indium oxide, and hydrogen-doped indium oxide. The composition of the metal material includes one or more of elemental copper, elemental titanium, elemental aluminum, elemental iron, elemental tungsten, and elemental magnesium.

4. A method for applying the etching paste as described in any one of claims 1 to 3, characterized in that, include: The etching paste is applied to the surface of the substrate to be etched to form an etching layer, the shape of which is matched to the target pattern to be etched; The substrate on which the etched layer is formed is heat-treated at a first temperature for a first time; Remove the etched layer after heat treatment to form an etched pattern on the substrate surface that conforms to the target pattern.

5. The method of applying the etching paste as described in claim 4, characterized in that, The first temperature is any value between 50℃ and 150℃, and the first time is any value between 5min and 60min.

6. The method of applying the etching paste as described in claim 4, characterized in that, The etching paste is used to form the etching layer by screen printing or scraping, and the line accuracy of the etched pattern is any value between 1μm and 1000mm.

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