CN111334298A - Molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution and preparation method thereof - Google Patents

Abstract

The invention discloses a molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution and a preparation method thereof, wherein the raw materials of the etching solution comprise, by weight, 55-75% of inorganic acid phosphoric acid, 2.5-5% of nitric acid, 12-28% of acetic acid, 1-8% of a surfactant, 0.1-5% of a complex metal inhibitor, 0.1-5% of a protective agent and the balance of pure water; the compound metal inhibitor is a compound mixture of at least two substances of molybdate, nitrate, mercaptobenzothiazole, lauric acid and mercaptobenzothiazole; the sum of the weight percentages of the components is 100 percent. The invention adds the compound metal inhibitor to ensure that the etching speed has controllability, effectively inhibits the deterioration of the corrosion-resistant protective layer, obtains the metal film with flat and smooth surface and has important application value.

Description

Molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution and preparation method thereof

Technical Field

The invention relates to the technical field of etching solutions, in particular to a molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution and a preparation method thereof.

Background

In recent years, flexible liquid crystal display products tend to be large-sized, high in image quality and functional, while the existing LEDs/OLEDs are gradually unable to meet the requirements of industry development, and accordingly, the modern AMOLED liquid crystal display technology is more and more concerned with perfect image quality, excellent performance and innovation. A large number of thin layers are provided on the AMOLED substrate, and since adhesion between aluminum or an aluminum alloy and a glass substrate as a base film is not good and it is easily corroded by acid, alkali and heat in the external environment, it is necessary to use a molybdenum or molybdenum alloy film layer as a lamination film on the upper and lower portions of the aluminum or the aluminum alloy, such as a molybdenum aluminum molybdenum (Mo/Al/Mo) structure; and etching the laminated film together with an etching solution to form a desired pattern.

ITO is the abbreviation of Indium Tin Oxides, has good conductivity and transparency as nano Indium Tin metal oxide, is sprayed on glass, plastics and electronic display screens to be used as a transparent conductive film, is usually compounded with metal silver with high conductivity and high reflectivity, can prepare an ITO/Ag/ITO film with excellent performance, obtains a multilayer film with high conductivity and high transflective reflectivity by adjusting the thickness of a film layer, and is used as an electrode material of a transflective liquid crystal display.

In the prior art, different etching solution systems are respectively adopted for the etching processes of the molybdenum-aluminum-molybdenum laminated structure panel and the ITO/Ag/ITO laminated structure panel, when the panels with different structures are etched, the etching solution needs to be replaced, and an etching tank needs to be cleaned, so that the time and the material are consumed; and if molybdenum aluminum molybdenum and ITO/Ag/ITO exist on the same panel, the etching is usually step-by-step, and the efficiency is low. However, if only a simple mixture of two etching solutions is used, the etching angle, etching time and etching precision are difficult to control due to the difference in reaction rate between the etching solution and each layer of thin film and the difference in thickness of the thin film, thereby affecting the uniformity and stability of the etched line.

Therefore, in order to reduce the cost, improve the etching efficiency and simplify the process, the inventor independently develops the molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution to increase the universality, improves the problem that the two laminated films cannot be compatibly etched by the existing etching solution, and reduces the problems of large cone angle even more than 90 degrees, rough surface and unsmooth line caused by the unmatched etching speed of the molybdenum-aluminum-molybdenum laminated film in the etching solution; the problems of silver layer retraction and ITO layer protrusion caused by over-fast silver ion etching are solved.

Disclosure of Invention

The invention aims to overcome the defects in the prior art and provide an etching solution compatible with a molybdenum-aluminum-molybdenum laminated film and an ITO/Ag/ITO laminated film, wherein the etching solution has an etching clearance angle of no more than 60 degrees for the molybdenum-aluminum-molybdenum laminated film, smooth edges and a side dimension loss of no more than 0.5 mu m; the loss of the side dimension of the ITO/Ag/ITO structure after etching is not more than 0.75 mu m, and no microcrystal remains on the surface of the substrate after etching.

In order to achieve the purpose, the technical scheme of the invention is to design a molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution, wherein the raw materials of the etching solution comprise, by weight, 55-75% of inorganic acid phosphoric acid, 2.5-5% of nitric acid, 12-28% of acetic acid, 1-8% of a surfactant, 0.1-5% of a complex metal inhibitor, 0.1-5% of a protective agent and the balance of pure water; the compound metal inhibitor is a compound mixture of at least two substances of molybdate, nitrate, mercaptobenzothiazole, lauric acid and mercaptobenzothiazole; the sum of the weight percentages of the components is 100 percent.

The etching solution is clear and transparent after being mixed and stirred uniformly, and when the flexible panel plated with the molybdenum-aluminum-molybdenum laminated film and the ITO/Ag/ITO laminated film acts in the etching solution, Mo is oxidized into MoO by nitric acid in the etching solution₂Phosphate ions and metal oxides form a complex, and because the phosphate ions are easy to ionize, the added compound metal inhibitor can control the ionization balance in the complex, so that the etching rate of Mo is reduced; meanwhile, the added compound metal inhibitor can improve the wettability and permeability of the etching solution and control the etching rate of the ITO; the protective agent is added, so that the viscosity of the etching solution can be increased, the reasonable concentration gradient of reactants and products on the etching surface in the etching process can be ensured, a certain complex can be formed with silver ions and attached to the surface of the metal silver, the contact area of the liquid medicine and the silver is reduced, the etching rate of the silver is reduced, and the etching rate of the silver is ensured to be relatively uniform and consistent with that of ITO. During continuous operation, an online concentration manager is adopted, contents of three main acids, namely phosphoric acid, acetic acid and nitric acid, in the liquid medicine are accurately and effectively monitored through an intelligent potentiometric titration analysis method, a consumed single acid is timely supplemented by an online liquid supplementing system, the content of the three acids in the liquid medicine is ensured within a reasonable control range, and therefore stability and consistency of online etching are guaranteed.

Further preferably, the molar ratio of the compound metal inhibitor is molybdate: nitrate salt: mercaptobenzothiazole: lauric acid: the ratio of the thiol benzothiazole to the thiol benzothiazole is 1:0.5-2:1-5:0.5-2: 1-5.

Further preferably, the pH value of the etching solution is 1.5-2.

The preferable technical scheme is that the surfactant is phosphate ester surfactant and/or amine oxide surfactant.

The further preferable technical scheme is that the phosphate surfactant is one or more of monolauryl phosphate, lauryl alcohol ether phosphate, potassium monolauryl phosphate, potassium lauryl alcohol ether phosphate, polyoxyethylene monoalkyl phosphate and polyoxyethylene dialkyl phosphate; the amine oxide surfactant is one or more of lauramidopropyl amine oxide, cocamidopropyl amine oxide, dodecyl dimethyl amine oxide and oleamidopropyl dimethyl amine oxide.

Further preferably, the molybdate is one or more selected from ammonium molybdate, sodium molybdate, potassium molybdate, ammonium phosphomolybdate and ammonium silicomolybdate.

Further preferably, the protecting agent is one or more of organic polybasic phosphoric acid, polysulfate and thiosulfate; the organic polybasic phosphoric acid is one of amino trimethylene phosphonic acid, ethylene diamine tetra methylene phosphonic acid, hydroxy ethylidene diphosphonic acid and diethylenetriamine penta methylene phosphonic acid.

The preparation method of the etching solution comprises the following test steps:

the first step is as follows: weighing acetic acid, nitric acid, phosphoric acid, a surfactant, a protective agent, molybdate, nitrate, mercaptobenzothiazole, lauric acid, mercaptobenzothiazole and pure water according to a ratio;

the second step is that: preparing a compound metal inhibitor: 1/3 of pure water is taken, and the weighed molybdate, nitrate, mercaptobenzothiazole, lauric acid and mercaptobenzothiazole are sequentially added into water for mixing and stirring, and the ultrasonic oscillation is carried out for uniform dispersion;

the third step: adding 1/3 amount of pure water required by the batching tank into the required amount of nitric acid under stirring, uniformly stirring and mixing, adding phosphoric acid and acetic acid into the mixed solution under stirring, uniformly mixing, then adding 1/3 amount of pure water, and fully stirring;

the fourth step: adding a surfactant, a protective agent and a prepared complex metal inhibitor into the mixture obtained in the third step, and fully stirring;

the fifth step: the mixture was filtered through a vacuum filter.

Further preferably, the aperture of the filter membrane of the vacuum filter is 0.01-0.1 μm; not more than 25 particles with the particle size larger than 0.5 mu m in each liter of the etching solution are filtered; the impurity anion is not more than 300ppb, and the impurity cation is not more than 100 ppb.

The invention has the advantages and beneficial effects that: the molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution can etch a panel plated with a molybdenum-aluminum-molybdenum laminated film and a panel plated with an ITO/Ag/ITO laminated film, the etching rates of a molybdenum layer, an aluminum layer, an ITO layer and an Ag layer are matched by inhibiting the etching rate of molybdenum and protecting the Ag layer, the etched molybdenum-aluminum-molybdenum laminated structure has a cone angle of less than 60 degrees, the side edge is smooth, the side edge size loss is less than 0.5 mu m, and no microcrystalline residue is left; the ITO/Ag/ITO laminated structure does not have the problems of Ag layer retraction and ITO bump exposure, and is suitable for continuous production.

Drawings

FIG. 1 is a scanning electron microscope photograph (cross-section) of a flexible panel coated with a Mo-Al-Mo laminate film by etching in accordance with example 1 of the present invention;

FIG. 2 is a scanning electron microscope photograph (cross-section) of a flexible panel coated with a Mo-Al-Mo laminate film etched after the flexible panel of example 1 of the present invention is left to stand for 20 days;

FIG. 3 is a scanning electron microscope (cross-section) photograph of a comparative example, a flexible panel having a molybdenum aluminum molybdenum laminate film etched;

FIG. 4 is a scanning electron microscope photograph (cross-section) of a flexible panel coated with an ITO/Ag/ITO laminate film according to example 1 of the present invention;

FIG. 5 is a scanning electron microscope photograph (cross-section) of a flexible panel coated with an ITO/Ag/ITO laminate film etched after standing for 20 days in example 1 of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made with reference to the accompanying drawings. The following examples are only for illustrating the technical solutions of the present invention more clearly, and the protection scope of the present invention is not limited thereby.

Example 1

Preparing an etching solution:

the first step is as follows: weighing 65% of phosphoric acid, 5% of nitric acid, 20% of acetic acid, 2% of monolauryl phosphate, 0.5% of hydroxyethylidene diphosphonic acid and 0.5% of compound metal inhibitor according to weight percentage, wherein the sodium molybdate is 0.1%, the potassium nitrate is 0.1%, the mercaptobenzothiazole is 0.1%, the lauric acid is 0.1%, the mercaptobenzothiazole is 0.1%, and the balance is water.

The second step is that: 1/3 of pure water is taken, and the weighed molybdate, nitrate, mercaptobenzothiazole, lauric acid and mercaptobenzothiazole are sequentially added into the water to be mixed and stirred, and the mixture is dispersed uniformly by ultrasonic oscillation.

The third step: adding 1/3 amount of pure water into the batching tank, adding nitric acid with required amount under stirring, and stirring and mixing uniformly; adding phosphoric acid and acetic acid into the mixed solution under stirring, mixing uniformly, adding 1/3-required pure water, and stirring fully;

the fourth step: adding lauryl phosphate, hydroxy ethylidene diphosphonic acid and prepared complex metal inhibitor into the mixture obtained in the third step, and fully stirring;

the fifth step: introducing the mixture into a vacuum filter for filtering, wherein the aperture of a filter membrane of the vacuum filter is 0.01-0.1 mu m, and the number of particles with the particle size larger than 0.5 mu m in each liter of the filtered etching solution is not more than 25; the impurity anion is not more than 300ppb, and the impurity cation is not more than 100 ppb.

Example 2

Preparing an etching solution: an etching solution was prepared according to the recipe and method of example 1, differing from example 1 in that 1.0% of a complex metal inhibitor was prepared, in which 0.2% of sodium molybdate, 0.2% of potassium nitrate, 0.2% of mercaptobenzothiazole, 0.2% of lauric acid, and 0.2% of mercaptobenzothiazole.

Example 3

Preparing an etching solution: an etching solution was prepared according to the recipe and method of example 1, differing from example 1 in that 1.5% of a complex metal inhibitor was prepared, in which 0.3% of sodium molybdate, 0.3% of potassium nitrate, 0.3% of mercaptobenzothiazole, 0.3% of lauric acid, and 0.3% of mercaptobenzothiazole.

Example 4

Preparing an etching solution: an etching solution was prepared according to the recipe and method of example 1, differing from example 1 in that 1.5% of a complex metal inhibitor was prepared, in which 0.3% of sodium molybdate, 0.25% of potassium nitrate, 0.3% of mercaptobenzothiazole, 0.25% of lauric acid, and 0.4% of mercaptobenzothiazole.

Example 5

Preparing an etching solution: an etching solution was prepared according to the recipe and method of example 1, differing from example 1 in that 1.5% of a complex metal inhibitor was prepared, in which 0.25% of sodium molybdate, 0.25% of potassium nitrate, 0.3% of mercaptobenzothiazole, 0.3% of lauric acid, and 0.4% of mercaptobenzothiazole.

Example 6

Preparing an etching solution: an etching solution was prepared according to the recipe and method of example 1, differing from example 1 in that the complex metal inhibitor was 2.0%, in which sodium molybdate was 0.4%, potassium nitrate was 0.4%, mercaptobenzothiazole was 0.4%, lauric acid was 0.4%, and mercaptobenzothiazole was 0.4%.

Example 7

Preparing an etching solution: an etching solution was prepared according to the recipe and method of example 1, except that 2.0% of a complex type metal inhibitor, in which sodium molybdate was 0.35%, potassium nitrate was 0.35%, mercaptobenzothiazole was 0.4%, lauric acid was 0.4%, and mercaptobenzothiazole was 0.5%, was used in the recipe.

Comparative example

Preparing an etching solution: an etching solution was prepared according to the formulation and method of example 1, except that no complexing metal inhibitor was added to the formulation.

And (3) testing the using effect of the etching solution: and etching the flexible panel plated with the molybdenum-aluminum-molybdenum laminated film for 70-90 s at 40 ℃ in the etching solution prepared by the comparative example and the examples 1-7, and observing the etched effect by magnifying the etching solution by 45k times through a scanning electron microscope after the etching is finished. The glass plate coated with the ITO/Ag/ITO laminated film was etched at 40 ℃ using the etching solutions prepared in examples 1 to 7, and after etching was completed, the effect after etching was observed by scanning electron microscopy at a magnification of 45 k.

TABLE 1 Experimental results for examples 1-7 and comparative examples

Referring to table 1 and fig. 1 to 5, it is found by comparison that after the compound metal inhibitor is added, the etching uniformity of the laminated film is significantly improved, the taper angle of the molybdenum-aluminum-molybdenum laminated film is less than 60 degrees, the edge is smooth, and the side dimension loss meets the customer requirement and is less than 0.5 μm; in contrast, the molybdenum-aluminum-molybdenum laminated film etched by the etching solution of the comparative example 1 has rough edges and unsmooth lines, and the aluminum layer leaks due to the phenomenon that the upper and lower molybdenum layers are etched too fast. The etching solution composition of example 1 after standing for 20 days is used for etching the flexible panel plated with the molybdenum-aluminum-molybdenum laminated film, and still has good etching performance. The size loss of the side edge of the ITO/Ag/ITO laminated film structure meets the requirement of a customer and is less than 0.75 mu m; no Ag indentation or ITO protrusion. The etching solution composition of example 1 after standing for 20 days was used to etch the flexible panel coated with the ITO/Ag/ITO laminated film, and still has good etching performance.

By comparing examples 1 to 7 with comparative example 1, it can be seen that by adjusting the ratio of the metal inhibitor, the etching rate is controlled and a good etching effect is obtained. Therefore, the etching solution can be compatible.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the technical principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (9)

1. The molybdenum-aluminum-molybdenum and ITO/Ag/ITO compatible etching solution is characterized in that the raw materials of the etching solution comprise, by weight, 55-75% of inorganic acid phosphoric acid, 2.5-5% of nitric acid, 12-28% of acetic acid, 1-8% of a surfactant, 0.1-5% of a compound metal inhibitor, 0.1-5% of a protective agent and the balance of pure water; the compound metal inhibitor is a compound mixture of at least two substances of molybdate, nitrate, mercaptobenzothiazole, lauric acid and mercaptobenzothiazole; the sum of the weight percentages of the components is 100 percent.

2. The molybdenum aluminum molybdenum and ITO/Ag/ITO compatible etchant of claim 1, wherein the complex metal inhibitor is a molybdate: nitrate salt: mercaptobenzothiazole: lauric acid: the ratio of the thiol benzothiazole to the thiol benzothiazole is 1:0.5-2:1-5:0.5-2: 1-5.

3. The molybdenum aluminum molybdenum and ITO/Ag/ITO compatible etching solution of claim 2, wherein the pH value of the etching solution is 1.5-2.

4. The molybdenum aluminum molybdenum and ITO/Ag/ITO compatible etching solution of claim 3, wherein the surfactant is a phosphate surfactant and/or an amine oxide surfactant.

5. The molybdenum aluminum molybdenum and ITO/Ag/ITO compatible etching solution of claim 4, wherein the phosphate surfactant is one or more of monolauryl phosphate, lauryl alcohol ether phosphate, potassium monolauryl phosphate, potassium lauryl alcohol ether phosphate, polyoxyethylene monoalkyl phosphate, and polyoxyethylene dialkyl phosphate; the amine oxide surfactant is one or more of lauramidopropyl amine oxide, cocamidopropyl amine oxide, dodecyl dimethyl amine oxide and oleamidopropyl dimethyl amine oxide.

6. The molybdenum aluminum molybdenum and ITO/Ag/ITO compatible etchant of claim 5, wherein the molybdate is selected from one or more of ammonium molybdate, sodium molybdate, potassium molybdate, ammonium phosphomolybdate, and ammonium silicomolybdate.

7. The Mo-Al-Mo and ITO/Ag/ITO compatible etchant of claim 6, wherein the protecting agent is one or more of organic polyphosphoric acid, polysulfate and thiosulfate; the organic polybasic phosphoric acid is one of amino trimethylene phosphonic acid, ethylene diamine tetra methylene phosphonic acid, hydroxy ethylidene diphosphonic acid and diethylenetriamine penta methylene phosphonic acid.

8. The method according to any one of claims 1 to 7, comprising the following test steps:

the first step is as follows: weighing acetic acid, nitric acid, phosphoric acid, a surfactant, a protective agent, molybdate, nitrate, mercaptobenzothiazole, lauric acid, mercaptobenzothiazole and pure water according to a ratio;

the second step is that: preparing a compound metal inhibitor: 1/3 of pure water is taken, and the weighed molybdate, nitrate, mercaptobenzothiazole, lauric acid and mercaptobenzothiazole are sequentially added into water for mixing and stirring, and the ultrasonic oscillation is carried out for uniform dispersion;

the third step: adding 1/3 amount of pure water required by the batching tank into the required amount of nitric acid under stirring, uniformly stirring and mixing, adding phosphoric acid and acetic acid into the mixed solution under stirring, uniformly mixing, then adding 1/3 amount of pure water, and fully stirring;

the fourth step: adding a surfactant, a protective agent and a prepared complex metal inhibitor into the mixture obtained in the third step, and fully stirring;

the fifth step: the mixture was filtered through a vacuum filter.

9. The Mo-Al-Mo and ITO/Ag/ITO compatible etching solution prepared by the method of claim 8, wherein the filter membrane aperture of the vacuum filter is 0.01-0.1 μm.

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