Etching solution, preparation method and application thereof

Abstract

The application discloses an etching liquid and a preparation method and application thereof, and belongs to the technical field of etchants. According to mass percentages, the etching liquid comprises 2.00-15.00 wt% of a peroxy acid, 2.00-15.00 wt% of organic acid A and 2.00-25.00 wt% of organic acid B, and the balance is water; the organic acid A comprises at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid and benzoic acid; and the organic acid B comprises at least one of methyl sulfonic acid, malic acid, citric acid, maleic acid and tartaric acid. Silver in a multilayer film formed by silver and an ITO film is etched by using the etching liquid, so that the problem of damage to a titanium-aluminum-titanium layer in a substrate caused by phosphoric acid and being not conducive to environmental protection is avoided, the ITO / Ag / ITO structure can be effectively removed, an excellent profile is formed, there is no silver and ITO residue, and no Ag resorption phenomenon occurs.

Description

Technical Field

[0001] The present invention relates to the technical field of etching agents, and in particular to an etching solution and a preparation method and application thereof. Background Art

[0002] With the advancement of technology, displays are widely used in mobile phones and tablets. The manufacturing process for organic light-emitting diodes (OLEDs) involves first forming a metal film on a substrate, then forming a protective film with a predetermined pattern on top of the film, which is then used as a mask to etch the metal film. Silver, a metal with high conductivity, carrier mobility, and brightness, is widely used in anode wiring (ITO / Ag / ITO) structures.

[0003] The etching solution currently used in the prior art is not only unable to effectively remove the ITO / Ag / ITO portion, but also causes certain damage to the titanium-aluminum-titanium layer in other portions of the substrate.

[0004] Among them, for the same substrate (glass substrate), its surface includes both ITO / Ag / ITO parts and titanium-aluminum-titanium parts (for example, the left area corresponds to the ITO / Ag / ITO part, and the right area corresponds to the titanium-aluminum-titanium part).

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] One of the purposes of the present invention is to provide an etching solution to solve the problem of damage to the titanium-aluminum-titanium layer caused by etching solution in the prior art.

[0007] A second object of the present invention is to provide a method for preparing the etching solution.

[0008] A third object of the present invention is to provide an application of the above etching solution.

[0009] In a first aspect, the present invention provides an etching solution comprising, by mass percentage, 2.00 wt% to 15.00 wt% of a peroxy acid, 2.00 wt% to 15.00 wt% of an organic acid A, and 2.00 wt% to 25.00 wt% of an organic acid B, with the remainder being water;

[0010] The organic acid A comprises at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, hexanoic acid and capric acid;

[0011] The organic acid B includes at least one of methanesulfonic acid, malic acid, citric acid, maleic acid and tartaric acid.

[0012] The above-mentioned peroxy acid acts as the main oxidant in the etching reaction, oxidizing the silver and ITO films to perform wet etching. Organic acid A acts as an auxiliary oxidant. During the etching process, as the content of the main oxidant decreases, the hydrogen ion concentration decreases, and the etching rate decreases. Organic matter A can continuously provide hydrogen ions, thereby ensuring the stability of the hydrogen ion concentration and the etching rate. Organic acid B is mainly used to provide additional hydrogen ions to adjust the pH value of the etching solution, so that the oxidation reaction can proceed smoothly and ensure that a better profile can be formed after etching.

[0013] The etching solution containing the peroxy acid, organic acid A and organic acid B in the above-mentioned ratio can avoid the use of phosphoric acid, which not only reduces the cost of the etching solution (including raw material cost and wastewater treatment cost, etc.), but also effectively avoids the problem of certain damage to the titanium aluminum titanium layer on other parts of the substrate surface caused by the use of phosphoric acid, and effectively removes the ITO / Ag / ITO structure.

[0014] In an optional embodiment, the etching solution further comprises 10.00 wt% to 30.00 wt% of an inorganic salt.

[0015] The inorganic salt can reduce the re-adsorption of silver (Ag) on ​​the ITO film by controlling the pH of the etching solution components, and can adjust the etching speed to achieve uniform etching when removing ITO film residues.

[0016] In an optional embodiment, the etching solution further comprises 0.01 wt%-1.00 wt% of a metal morphology improver.

[0017] Metal morphology improvers can improve the morphology of silver and ITO films.

[0018] In an optional embodiment, the etching solution includes 7.00-12.00wt% of peracid, 10.00wt%-15.00wt% of organic acid A, 5.00wt%-25.00wt% of organic acid B, 15.00wt%-25.00wt% of inorganic salt and 0.30wt%-1.00wt% of metal morphology improver, and the balance is water.

[0019] In an optional embodiment, the etching solution includes 10.00 wt % of peroxy acid, 15.00 wt % of organic acid A, 15.00 wt % of organic acid B, 25.00 wt % of inorganic salt and 1.00 wt % of metal morphology improver, with the balance being water.

[0020] The etching solution corresponding to this preferred solution not only does not damage the titanium-aluminum-titanium layer on the substrate surface, but also can more effectively remove the ITO / Ag / ITO structure, forming a more excellent profile, without silver and ITO residues, and without Ag re-adsorption.

[0021] In an alternative embodiment, the peroxyacid comprises at least one of peroxymonosulfuric acid, peroxydisulfuric acid, and peracetic acid.

[0022] The above-mentioned peroxy acid is a weak acid, which can effectively prevent the titanium-aluminum-titanium layer from being damaged, and can effectively oxidize ITO and silver together with other organic acids.

[0023] In an optional embodiment, the inorganic salt includes at least one of sodium sulfate, potassium sulfate, calcium sulfate, ferric sulfate, ferrous sulfate, sodium chloride, calcium chloride, potassium chloride, sodium bisulfate, potassium nitrate, ammonium nitrate, sodium nitrate, silver nitrate, calcium nitrate, sodium dihydrogen phosphate and ammonium sulfate.

[0024] The above-mentioned inorganic salts can provide sufficient sulfate, nitrate and chloride ions, which can combine with hydrogen ions in the solution to form sulfuric acid, nitric acid and hydrochloric acid respectively. The presence of acid causes the silver adsorbed on the surface of the substrate to dissolve again, thereby reducing the re-adsorption of silver (Ag) in the film and adjusting the etching speed to achieve uniform etching when removing ITO.

[0025] In an optional embodiment, the metal morphology improving agent includes at least one of ferric nitrate, ferrous nitrate, ferric sulfate and ferrous sulfate.

[0026] The above-mentioned metal morphology improver can effectively improve the morphology problems of Ag and ITO.

[0027] In a second aspect, the present invention provides a method for preparing the etching solution according to any one of the aforementioned embodiments, comprising the following steps: mixing the raw materials according to a proportion.

[0028] In an optional embodiment, the inorganic salt, metal morphology modifier and water are first mixed, then mixed with peroxy acid for a second time, and then mixed with organic acid A and organic acid B for a third time, which is conducive to uniform mixing between the raw materials.

[0029] In a third aspect, the present invention provides a use of the etching solution according to any one of the aforementioned embodiments, which can be used, for example, to etch a multilayer film composed of Ag and ITO films.

[0030] In an optional embodiment, the multilayer film is an ITO / Ag / ITO composite film.

[0031] The beneficial effects of the present invention include:

[0032] The etching solution involved in this application, by setting specific components and matching them in specific ratios, can avoid the use of phosphoric acid in the etching solution. This not only reduces the cost of the etching solution (including raw material costs and wastewater treatment costs, etc.), but also effectively avoids the problem of certain damage to the titanium-aluminum-titanium layer on the substrate surface caused by the use of phosphoric acid. Through practical application, it has been proven that this etching solution can effectively remove the ITO / Ag / ITO structure, forming an excellent profile, without Ag and ITO residues, and without Ag re-adsorption, and without damaging the titanium-aluminum-titanium layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 This is a SEM cross-sectional view of the ITO / Ag / ITO film layer after etching, corresponding to Example 2 in the experimental example, for observing the profile of the metal after etching;

[0035] Figure 2 This is a SEM TOP image of the ITO / Ag / ITO film layer after etching, corresponding to Example 2 in the experimental example, for observing the metal residue on the surface of the substrate after etching;

[0036] Figure 3 This is a SEM TOP image of the ITO / Ag / ITO film layer after etching, corresponding to Example 2 in the experimental example, for observing the silver adsorption condition on the surface of the substrate after etching;

[0037] Figure 4 This is a SEM TOP image of the ITO / Ag / ITO film layer after etching, corresponding to Example 2 in the experimental example, for observing the damage of the titanium-aluminum-titanium layer after etching;

[0038] Figure 5 This is a SEM TOP image of the ITO / Ag / ITO film layer after etching, corresponding to Comparative Example 1 in the experimental example, used to observe the damage of the titanium-aluminum-titanium layer after etching. DETAILED DESCRIPTION

[0039] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0040] The etching solution provided in this application, its preparation method and application are described in detail below.

[0041] The inventors propose that one of the reasons why the etching solution used in the prior art cannot effectively remove the ITO / Ag / ITO structure and also causes certain damage to the titanium-aluminum-titanium layer on the substrate surface is that the etching solution contains phosphoric acid.

[0042] Phosphoric acid is relatively expensive and can cause some damage to the titanium, aluminum, and titanium layers of the substrate. In severe cases, it can even cause excessive damage, resulting in a defective product. Furthermore, the phosphorus content of wastewater discharge typically needs to be controlled within 0.50 mg / L to prevent eutrophication, which can lead to excessive algae growth and subsequent deterioration of water quality and ecosystem degradation. However, controlling it within 0.50 mg / L significantly increases the production cost of the etching solution. The acid used in this application does not suffer from the problem of phosphorus-induced eutrophication of water bodies and is more affordable than phosphoric acid.

[0043] This application creatively proposes an etching solution that avoids the use of phosphoric acid in the etching solution, which not only reduces the cost of the etching solution (including raw material costs and wastewater treatment costs), but also effectively avoids the problem of certain damage to the titanium-aluminum-titanium layer on the substrate surface caused by the use of phosphoric acid. Through practical application, it has been demonstrated that this etching solution can effectively remove the ITO / Ag / ITO structure, forming an excellent profile, without Ag and ITO residues, without Ag re-adsorption, and without damaging the titanium-aluminum-titanium layer.

[0044] For reference, the etching solution involved in the present application may include 2.00wt%-15.00wt% of peroxy acid, 2.00wt%-15.00wt% of organic acid A and 2.00wt%-25.00wt% of organic acid B, with the balance being water, in terms of mass percentage.

[0045] Specifically, the amount of peroxyacid can be 2.00wt%, 3.00wt%, 4.00wt%, 5.00wt%, 6.00wt%, 7.00wt%, 8.00wt%, 9.00wt%, 10.00wt%, 11.00wt%, 12.00wt%, 13.00wt%, 14.00wt% or 15.00wt%, or any other value within the range of 2.00wt%-15.00wt%.

[0046] It should be noted that setting the peracid dosage between 2.00wt% and 15.00wt% can achieve a suitable etching rate for the ITO layer and reduce metal residue after etching. If the peracid dosage in the above-mentioned etching solution is less than 2.00wt%, it can easily lead to difficulty in etching the top ITO layer, resulting in a too low etching rate, causing collapse of the ITO at the top edge and poor etched cross-sectional profile. If it is above 15.00wt%, the oxidizing property is too high, which can easily lead to an excessively fast reaction rate of silver, excessive etching on one side, and poor production line performance.

[0047] In the present application, peroxy acid serves as the main oxidant in the etching reaction, oxidizing Ag and ITO to perform wet etching without damaging titanium, aluminum, and titanium.

[0048] For example, the peroxy acid may include at least one of peroxymonosulfuric acid and peroxydisulfuric acid, and may also include peracetic acid or the like.

[0049] The above-mentioned peroxy acid is a weak acid, which can effectively prevent the titanium-aluminum-titanium layer from being damaged, and can effectively oxidize ITO and silver together with other organic acids.

[0050] In some preferred embodiments, the peroxyacid is selected from at least one of peroxymonosulfuric acid and peroxydisulfuric acid. The reasons for this include: using peroxymonosulfuric acid and / or peroxydisulfuric acid can better etch the ITO film than other peroxyacids, thereby reducing metal residue.

[0051] The amount of organic acid A can be 2.00wt%, 3.00wt%, 4.00wt%, 5.00wt%, 6.00wt%, 7.00wt%, 8.00wt%, 9.00wt%, 10.00wt%, 11.00wt%, 12.00wt%, 13.00wt%, 14.00wt% or 15.00wt%, etc., or it can be any other value within the range of 2.00wt%-15.00wt%.

[0052] It should be noted that the amount of organic acid A is set at 2.00wt%-15.00wt% to control the reaction rate within a reasonable range. If the amount of organic acid A in the etching solution is less than 2.00wt%, it is likely to cause significant ITO residue on the substrate surface; if it is greater than 15.00wt%, it is likely to result in large single-sided etching, which is not conducive to line width control.

[0053] In the present application, the organic acid A acts as an auxiliary oxidant. As the content of the main oxidant decreases in the etching process, the concentration of hydrogen ions decreases, and the etching speed will decrease. However, the organic acid A can continuously provide hydrogen ions, thereby ensuring the stability of the hydrogen ion concentration and ensuring the etching speed. Illustratively, the above-mentioned organic acid A can include at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, hexanoic acid, and decanoic acid.

[0054] The amount of the organic acid B can be 2.00wt%, 3.00wt%, 4.00wt%, 5.00wt%, 6.00wt%, 7.00wt%, 8.00wt%, 9.00wt%, 10.00wt%, 11.00wt%, 12.00wt%, 13.00wt%, 14.00wt%, 15.00wt%, 16.00wt%, 17.00wt%, 18.00wt%, 19.00wt%, 20.00wt%, 21.00wt%, 22.00wt%, 23.00wt%, 24.00wt%, or 25.00wt%, etc., or any other value within the range of 2.00wt%-25.00wt%.

[0055] It should be noted that the amount of the organic acid B is set to be within the range of 2.00wt%-25.00wt%. Because the etching speed of silver is extremely fast, the addition of the organic acid B can significantly increase the etching rate of ITO, reduce the risk of collapse of the top ITO due to slow etching, reduce the adsorption amount of silver on the substrate, and improve the yield of the etched product. If the amount of the organic acid B in the above-mentioned etching solution is less than 2.00wt%, it is easy to cause a large amount of silver adsorption. If the amount of the organic acid B is more than 25.00wt%, it is easy to cause the ITO etching speed to be too fast, and the single-side etching amount to increase.

[0056] In the present application, the organic acid B is mainly used to adjust the pH value of the etching solution, so that the oxidation reaction can proceed smoothly, and a relatively excellent profile can be formed after etching.

[0057] Illustratively, the above-mentioned organic acid B can include at least one of methyl sulfonic acid, malic acid, citric acid, maleic acid, and tartaric acid.

[0058] Further, the etching solution involved in the present application can further include 10.00wt%-30.00wt% of inorganic salt.

[0059] Specifically, the amount of inorganic salt can be 10.00wt%, 11.00wt%, 12.00wt%, 13.00wt%, 14.00wt%, 15.00wt%, 16.00wt%, 17.00wt%, 18.00wt%, 19.00wt%, 20.00wt%, 21.00wt%, 22.00wt%, 23.00wt%, 24.00wt%, 25.00wt%, 26.00wt%, 27.00wt%, 28.00wt%, 29.00wt%, or 30.00wt%, etc., or any other value within the range of 10.00wt%-30.00wt%.

[0060] It should be noted that the amount of inorganic salt is set to 10.00wt%-30.00wt%, which can effectively control the pH of the etching solution. If the amount of inorganic salt in the above etching solution is less than 10.00wt%, it is easy to cause insufficient acidity of the etching solution and ITO residue; if it is more than 30.00wt%, it is easy to cause inorganic salt precipitation in the production line, causing defects.

[0061] In this application, the inorganic salt can reduce the re-adsorption of silver (Ag) in the film and adjust the etching speed to uniformly etch when removing ITO.

[0062] Exemplarily, the above-mentioned inorganic salt can include at least one of sodium sulfate, potassium sulfate, calcium sulfate, sodium chloride, calcium chloride, potassium chloride, sodium bisulfate, potassium nitrate, ammonium nitrate, sodium nitrate, silver nitrate, calcium nitrate, sodium dihydrogen phosphate, and ammonium sulfate.

[0063] The above-mentioned inorganic salt can provide sufficient sulfate, nitrate, and chloride ions, which can combine with hydrogen ions in the solution to form sulfuric acid, nitric acid, and hydrochloric acid, respectively. The presence of acid causes the re-dissolution of silver adsorbed on the surface of the substrate, thereby reducing the re-adsorption of silver (Ag) in the film and adjusting the etching speed to uniformly etch when removing ITO.

[0064] Further, the etching solution involved in the present application can also include 0.01wt%-1.00wt% of a metal morphology modifier.

[0065] Specifically, the amount of metal morphology modifier can be 0.01wt%, 0.02wt%, 0.05wt%, 0.08wt%, 0.10wt%, 0.20wt%, 0.30wt%, 0.40wt%, 0.50wt%, 0.60wt%, 0.70wt%, 0.80wt%, 0.90wt%, or 1.00wt%, etc., or any other value within the range of 0.01wt%-1.00wt%.

[0066] It should be noted that the amount of metal morphology modifier used in the etching solution is set at 0.01wt%-1.00wt%, which can improve the silver residue to a certain extent. If the amount of metal morphology modifier used in the etching solution is less than 0.01wt%, it is likely to be too low and fail to achieve the desired morphology improvement effect. If it is greater than 1.00wt%, it is likely to lead to excessively high metal ion concentration in the solution, affecting the etching properties of the etching solution.

[0067] In the present application, the metal morphology improver can improve the morphology of Ag and ITO.

[0068] For example, the metal morphology improving agent may include at least one of ferric nitrate, ferrous nitrate, ferric sulfate and ferrous sulfate.

[0069] The metal morphology residue improver is an iron-containing metal salt, which reduces the speed at which the etching solution penetrates into the pinholes of the upper ITO layer, thereby preventing the occurrence of mouse bite phenomenon and significantly improving the morphology after etching.

[0070] In some preferred embodiments, the etching solution involved in the present application includes 7.00-12.00wt% of peroxy acid, 10.00wt%-15.00wt% of organic acid A, 5.00wt%-25.00wt% of organic acid B, 15.00wt%-25.00wt% of inorganic salt and 0.30wt%-1.00wt% of metal morphology improver, and the balance is water.

[0071] In some more preferred embodiments, the etching solution includes 10.00 wt % of peroxy acid, 15.00 wt % of organic acid A, 15.00 wt % of organic acid B, 25.00 wt % of inorganic salt and 1.00 wt % of metal morphology improver, and the balance is water.

[0072] The etching solution corresponding to the above preferred embodiment not only does not damage the titanium-aluminum-titanium layer on the substrate surface, but also can more effectively remove the ITO / Ag / ITO portion on the substrate surface, forming a better profile without silver and ITO residues and without silver re-adsorption.

[0073] Correspondingly, the present invention also provides a method for preparing the above etching solution, comprising the following steps: mixing the raw materials according to a proportion.

[0074] In some optional embodiments, the inorganic salt, metal morphology modifier and water may be mixed for the first time, then mixed with the peracid for the second time, and then mixed with the organic acid A and the organic acid B for the third time, which is conducive to uniform mixing of the raw materials.

[0075] In addition, the present invention also provides an application of the above etching solution, for example, it can be used to etch a multilayer film composed of Ag and ITO films.

[0076] As a reference, the multilayer film can be an ITO / Ag / ITO composite film.

[0077] By etching the multilayer film composed of silver and ITO film with the etching solution provided in the present application, the ITO / Ag / ITO structure can be effectively removed, an excellent profile can be formed, there is no silver and ITO residue, and no Ag re-adsorption phenomenon occurs, and there is no damage to the titanium aluminum titanium film layer.

[0078] The features and properties of the present application are further described in detail below in conjunction with examples.

[0079] Example 1

[0080] The present example provides an etching solution (10.00 kg), which contains 5.00 wt% of peroxydic acid, 10.00 wt% of acetic acid (organic acid A), 25.00 wt% of sodium bisulfate (inorganic salt), 15.00 wt% of methyl sulfonic acid (organic acid B), and 1.00 wt% of ferric nitrate (metal morphology modifier), and the balance is deionized water.

[0081] The etching solution is prepared by the following method:

[0082] The deionized water, inorganic salt, metal morphology modifier, peroxy acid, organic acid A and organic acid B are weighed according to the above proportions, respectively. The inorganic salt, metal morphology modifier and deionized water are first stirred and dissolved, then the peroxy acid is added and stirred until uniform, and then the organic acid A and organic acid B are added and stirred (30 min) until uniform.

[0083] Examples 2-10 and Comparative Examples 1-9

[0084] The compositions of the etching solutions corresponding to Examples 2-10 and Comparative Examples 1-9 are shown in Table 1, and the preparation method of the etching solution is referred to Example 1.

[0085] The total mass of the etching solution corresponding to each example and comparative example is 10.00 kg.

[0086] Table 1 Composition

[0087]

[0088]

[0089] Test Example

[0090] The etching solutions (10 kg) of Examples 1-10 and Comparative Examples 1-9 above are used to etch ITO / Ag / ITO, respectively, and the etching characteristics, residue, and titanium aluminum titanium damage are observed.

[0091] Specifically, 10 kg of etching solution was poured into the mini etching device, and etching was performed after the temperature reached 40±0.1°C. Because the EPD (etching completion time) of the underlying ITO could not be observed, only the time when the etching of the ITO / Ag two-layer film was completed could be observed. The total etching time was 1.5 times the EPD of the ITO / Ag two-layer film. After the etching was completed, it was rinsed with deionized water within 2 seconds, and the moisture on the surface was blown dry. After the completion, it was observed using a scanning electron microscope, and the performance parameters after etching were further evaluated.

[0092] The performance parameter evaluation criteria are as follows:

[0093] ①. The evaluation criteria for single-side etching amount (the distance between the edge of the photoresist after etching and the silver after etching) are as follows:

[0094] ○: Excellent [single-side etching amount: 0.40-0.60 μm];

[0095] △: Good [single-side etching amount: 0.30-0.40 μm];

[0096] ×: Defective [single-side etching amount: 0.60 μm or more or 0.30 μm or less].

[0097] ②. Silver re-adsorption (number of Ag particles adsorbed on the surface under SEM 20K magnification) evaluation criteria are as follows:

[0098] ○: Excellent [less than 10];

[0099] △: good [10-30];

[0100] ×: Defective [30 or more].

[0101] ③. The evaluation criteria for residue (number of Ag / ITO residual particles on the surface under SEM 20K magnification) are as follows:

[0102] ○: Excellent [less than 10];

[0103] △: good [10-30];

[0104] ×: Defective [30 or more].

[0105] ④、The evaluation criteria for titanium, aluminum and titanium damage are as follows:

[0106] ○: Excellent [no damage at all (no Al indentation)];

[0107] △: Good [slight damage occurs (Al indentation is less than 0.10 μm)];

[0108] ×: Defective [serious damage occurred (Al indentation exceeded 0.10 μm)].

[0109] The evaluation results are shown in Table 2.

[0110] Table 2 Evaluation results

[0111]

[0112]

[0113] As can be seen from Table 2, when etching was carried out using the etching solutions of Examples 1-10, no titanium, aluminum, and titanium damage problems occurred, and indicators such as unilateral etching amount, residue, and Ag re-adsorption were all good or excellent. Specifically, compared with Example 2, Example 1 may have a certain amount of ITO residue due to the low content of peroxydisulfuric acid. Comparing Example 2 with Example 4, it can be found that the use of acetic acid, which belongs to organic acid A, is more conducive to solving the silver adsorption problem than the use of terephthalic acid. The organic acid B of Example 5 is malic acid. Compared with Example 2, it can be found that methanesulfonic acid is more conducive to solving the residue problem. In Examples 6 and 7, when the content of methanesulfonic acid and inorganic salts was insufficient, there was a certain amount of residue, but good test results were still maintained. Example 10 used peracetic acid as the main oxidant. The hydrogen ions provided by peracetic acid were less than those of peroxydisulfuric acid, and the reaction rate with the metal was insufficient, resulting in residue.

[0114] When etching was performed using the etching solutions of Comparative Examples 1-9, Ag adsorption and titanium, aluminum, and titanium damage problems occurred. This may be because phosphoric acid corrodes titanium, aluminum, and titanium faster than organic acids. Comparative Examples 1-3 did not add organic acid B and adjusted different contents of phosphoric acid for comparison with Example 2. Comparative Examples 1-3 all experienced Ag re-adsorption and titanium, aluminum, and titanium damage problems, and when the phosphoric acid content was low, the amount of residue was not very good. Comparative Example 5 added inorganic salts, and the residue was improved to a certain extent compared with Comparative Examples 1-2, but the problems of Ag re-adsorption and titanium, aluminum, and titanium damage were still not solved. Comparative Examples 6-8 did not add organic acid A and adjusted different contents of phosphoric acid for comparison with Example 2. Comparative Examples 6-8 also experienced Ag re-adsorption and titanium, aluminum, and titanium damage problems. Comparative Example 9 did not contain organic acid A and organic acid B compared with Example 2, and replaced organic acid A and organic acid B with phosphoric acid. The results also showed that Ag adsorption and titanium, aluminum, and titanium damage problems occurred.

[0115] Furthermore, taking Example 2 and Comparative Example 1 as examples, etching results were compared.

[0116] Figure 1 The SEM cross-sectional view of the ITO / Ag / ITO film layer after etching corresponding to Example 2 is shown in FIG. Figure 1 It can be seen that the etching solution provided in Example 2 has a very good etching effect on the ITO / Ag / ITO film layer.

[0117] Figure 2 The SEM TOP image of the ITO / Ag / ITO film layer after etching corresponding to Example 2 is shown in FIG. Figure 2 It can be seen that the etching solution provided in Example 2 does not leave any residue after etching the ITO / Ag / ITO film layer.

[0118] Figure 3 The SEM TOP image of the ITO / Ag / ITO film layer after etching corresponding to Example 2 is shown in FIG. Figure 3 It can be seen that no Ag adsorption occurs after the etching solution provided in Example 2 etches the ITO / Ag / ITO film layer.

[0119] Figure 4 The SEM TOP image of the ITO / Ag / ITO film layer after etching corresponding to Example 2 is shown in FIG. Figure 4 It can be seen that the etching solution provided in Example 2 does not damage the titanium-aluminum-titanium film layer.

[0120] Figure 5 The SEM TOP image of the ITO / Ag / ITO film after etching corresponding to Comparative Example 1 is shown in FIG. Figure 5 It can be seen that the etching solution provided in Comparative Example 1 causes certain damage to the titanium-aluminum-titanium film layer.

[0121] In summary, the etching solution provided in the present application has a low cost and is mainly suitable for etching silver in a multilayer film composed of silver and ITO film. It not only avoids the problem of certain damage to the titanium-aluminum-titanium layer on the surface of the substrate caused by the use of phosphoric acid and is not conducive to environmental protection, but also can effectively remove the ITO / Ag / ITO structure to form an excellent profile, without silver and ITO residues, and no silver re-adsorption occurs.

[0122] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. An etching solution, characterized in that The etching solution comprises, by mass percentage, 2.00 wt % to 15.00 wt % of a peroxy acid, 2.00 wt % to 15.00 wt % of an organic acid A, 2.00 wt % to 25.00 wt % of an organic acid B, 10.00 wt % to 30.00 wt % of an inorganic salt, and 0.01 wt % to 1.00 wt % of a metal morphology improver, with the balance being water; The organic acid A comprises at least one of formic acid, acetic acid, propionic acid, butyric acid, octanoic acid, adipic acid, oxalic acid, malonic acid, benzoic acid, phenylacetic acid, phthalic acid, terephthalic acid, valeric acid, hexanoic acid and capric acid; The organic acid B includes at least one of methanesulfonic acid, malic acid, maleic acid and tartaric acid; The inorganic salt includes at least one of sodium sulfate, potassium sulfate, calcium sulfate, ferrous sulfate, ferrous sulfate, sodium chloride, calcium chloride, potassium chloride, sodium bisulfate, potassium nitrate, ammonium nitrate, sodium nitrate, silver nitrate, calcium nitrate, sodium dihydrogen phosphate and ammonium sulfate; The metal morphology improving agent includes at least one of ferric nitrate, ferrous nitrate, ferric sulfate and ferrous sulfate.

2. The etching solution according to claim 1, wherein The etching solution includes 7.00-12.00wt% of the peroxy acid, 10.00wt%-15.00wt% of the organic acid A, 5.00wt%-25.00wt% of the organic acid B, 15.00wt%-25.00wt% of the inorganic salt and 0.30wt%-1.00wt% of the metal morphology improver, with the balance being water.

3. The etching solution according to claim 2, wherein The etching solution includes 10.00 wt % of the peroxy acid, 15.00 wt % of the organic acid A, 15.00 wt % of the organic acid B, 25.00 wt % of the inorganic salt and 1.00 wt % of the metal morphology improver, with the balance being water.

4. The etching solution according to any one of claims 1 to 3, characterized in that The peroxy acid includes at least one of peroxymonosulfuric acid, peroxydisulfuric acid and peracetic acid.

5. The method for preparing the etching solution according to any one of claims 1 to 4, wherein: The method comprises the following steps: mixing raw materials according to a proportion.

6. The preparation method according to claim 5, characterized in that The inorganic salt, the metal morphology improver and the water are first mixed, then mixed with the peroxy acid for the second time, and then mixed with the organic acid A and the organic acid B for the third time.

7. Use of the etching solution according to any one of claims 1 to 4, characterized in that: The etching solution is used to etch the multilayer film composed of Ag and ITO films.

8. The use according to claim 7, characterized in that The multilayer film is an ITO / Ag / ITO composite film.

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