CN113201345A - ITO etching solution for TFT-LCD display screen and preparation method thereof - Google Patents

Abstract

The invention relates to the technical field of wet electronic chemicals, and discloses an ITO (indium tin oxide) etching solution for a TFT-LCD (thin film transistor-liquid crystal display) display screen, which comprises the following components in percentage by weight: 10-20% of sulfuric acid, 1-5% of additive, 0.05-0.5% of surfactant, 0.01-0.1% of defoaming agent and the balance of water, wherein the additive is a mixture of inorganic salt and organic matters; the etching solution disclosed by the invention takes sulfuric acid as a main component, the production process is simple, and the acid concentration is easy to control and detect on line; the surfactant is added, so that the surface tension of the ITO etching solution is low, the cloud point is absent, the wetting force is strong, the surface tension of the ITO etching solution is effectively reduced, and the rate is moderate in the etching process; the defoaming agent can eliminate foams generated by a surfactant in the etching process, meets the high-precision processing requirement of ITO film etching, has no damage effect on light resistance, and has good protection effect on etched lines and complete patterns; meanwhile, the gradient of the etched ITO inclined plane can be regulated by the inorganic salt, so that the requirements of customers can be better met.

Description

ITO etching solution for TFT-LCD display screen and preparation method thereof

Technical Field

The invention relates to the technical field of wet electronic chemicals, in particular to an ITO (indium tin oxide) etching solution for a TFT-LCD (thin film transistor-liquid crystal display) display screen and a preparation method thereof.

Background

The TFT-LCD has high resolution and good image display effect, has low energy consumption, lower and lower cost and better image effect, and benefits from the continuous innovation and cost reduction of basic chemical materials. In the production and manufacture of TFT-LCD, the TFT structure is used as the switch of the electrode to play a very important role in the display, and the etching of ITO film is the last process in the manufacture of TFT pattern Array. After the ITO film is sputtered, a layer of photoresist is covered, the pattern is exposed and developed, the ITO film is etched by etching liquid, and then the photoresist is stripped to form the required pattern. In addition, with the development of the display industry, the production line process is continuously updated, and higher requirements are also provided for the etching precision, so that the development of an adjustable ITO etching solution is particularly necessary to meet the requirements of a customer etching process and a process.

In the prior art, CN201210206045.5 discloses an aqua regia system of nitric acid/hydrochloric acid, CN201110132527.6 discloses a hydrochloric acid/acetic acid system, CN201911163144.8 discloses a ferric trichloride/hydrochloric acid system, and CN201610860973.1 discloses a sulfuric acid/nitric acid system, the content of the used acid is high, the etching reaction is violent, the etching precision is difficult to control, the etching solution is not suitable for an ITO film layer with small thickness, the cost of the etching solution is high, in addition, the components of the etching solution contain volatile components, and the etching solution needs to be continuously supplemented to ensure the stable content of the components in the using process.

Disclosure of Invention

Technical problem to be solved

Aiming at the defects of the prior art, the invention provides an ITO etching solution for a TFT-LCD display screen and a preparation method thereof, and solves the problems in the background art.

(II) technical scheme

In order to achieve the purpose, the invention provides the following technical scheme: an ITO etching solution for a TFT-LCD display screen comprises the following components in percentage by weight: 10 to 20 percent of sulfuric acid, 1 to 5 percent of additive, 0.05 to 0.5 percent of surfactant, 0.01 to 0.1 percent of defoaming agent and the balance of water, wherein the additive is a mixture of inorganic salt and organic matter.

Preferably, the inorganic salt is any one selected from the group consisting of ammonium acetate, ammonium sulfate, ammonium nitrate, potassium sulfate, monopotassium phosphate, potassium acetate, and potassium citrate.

Preferably, the organic matter is any one of methyl tetrazole, imidazole, 2-mercaptoimidazole, 2-mercapto-5-methylbenzimidazole, 1,2, 4-triazole, 4-amino-4H-1, 2, 4-triazole and benzotriazole.

Preferably, the preparation method of the ITO etching solution for the TFT-LCD display screen comprises the following steps:

s1, adding a certain amount of high-purity water into the mixing kettle;

s2, adding a certain amount of concentrated sulfuric acid under the condition of continuous stirring, circulating for 2 hours, opening a cooling system, and cooling the sulfuric acid solution to 30 ℃;

s3, adding additives, surfactants and defoaming agents into the mixing kettle in proportion, and circulating for 30 min;

s4, filtering the mixed liquid by a 0.1-micron filter to obtain the ITO etching liquid.

(III) advantageous effects

The invention provides an ITO etching solution for a TFT-LCD display screen and a preparation method thereof, and the ITO etching solution has the following beneficial effects:

the etching solution disclosed by the invention takes sulfuric acid as a main component, the production process is simple, and the acid concentration is easy to control and detect on line; the surfactant is added, so that the surface tension of the ITO etching solution is low, the cloud point is absent, the wetting force is strong, the surface tension of the ITO etching solution is effectively reduced, and the rate is moderate in the etching process; the defoaming agent can eliminate foams generated by a surfactant in the etching process, meets the high-precision processing requirement of ITO film etching, has no damage effect on light resistance, and has good protection effect on etched lines and complete patterns; meanwhile, the gradient of the etched ITO inclined plane can be regulated and controlled by the adopted inorganic salt, so that the requirements of customers can be better met; an organic matter is used as an additive, has excellent corrosion resistance effect on lower-layer metals Al, Mo and Cu, and can well meet the requirements of technical process and manufacturing procedure; in addition, the etching solution takes low-cost sulfuric acid as a raw material, and is favorable for reducing the cost of the etching solution on the basis of meeting the requirements of technical processes and manufacturing procedures.

Drawings

FIG. 1 is a cross-sectional view of an ITO film etched by an etching solution according to an embodiment of the present invention;

FIG. 2 is a cross-sectional view of a Mo, Al, Cu metal layer etched by an etching solution according to an embodiment of the present invention;

FIG. 3 is a plan view of an embodiment of the present invention;

FIG. 4 is a cross-sectional view of an ITO film etched by an etchant according to comparative example 1 of the present invention;

FIG. 5 is a cross-sectional view of an ITO film etched by an etchant according to comparative example 2 of the present invention;

FIG. 6 is a cross-sectional view of a Mo, Al, Cu metal layer etched by an etchant in comparative example 3 of the present invention;

FIG. 7 is a schematic plan view of the Cu metal layer etched by the etching solution in comparative example 3 of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Examples

An ITO etching solution for a TFT-LCD display screen comprises the following components in percentage by weight: 14 wt% of sulfuric acid, 3 wt% of ammonium sulfate, 1 wt% of 2-mercaptoimidazole, 0.1% of surfactant, 0.05% of defoaming agent and the balance of water.

The etching object of the etching solution is

The ITO film is etched for 50s at the etching temperature of 40 ℃; the etching result is shown in fig. 1, the unilateral CD after etching is 0.0595um, and the slope angle of ITO is 33 °; FIG. 2 shows the result of Mo, Al and Cu being etched by the etching solution respectively, the etching time is 600s, the etching temperature is 40 ℃, and the etching solution has no corrosion to the Mo, Al and Cu metal layers; FIG. 3 shows the result of etching a Cu glass sheet 600s with an etchant, and no pitting phenomenon was observed.

Comparative example 1

An ITO etching solution for a TFT-LCD display screen comprises the following components in percentage by weight: 14 wt% of sulfuric acid, 1 wt% of 2-mercaptoimidazole, 0.1% of surfactant, 0.05% of defoaming agent and the balance of water.

The etching solution is used for etching the object

The etching time of the ITO film was 50s, the etching temperature was 40 ℃, the etching result is shown in FIG. 4, the single-sided CD after etching was 0.0595um, and the ITO slope angle was 23 °.

Comparative example 2

An ITO etching solution for a TFT-LCD display screen comprises the following components in percentage by weight: 14 wt% of sulfuric acid, 5 wt% of ammonium sulfate, 1 wt% of 2-mercaptoimidazole, 0.1% of surfactant, 0.05% of defoaming agent and the balance of water.

The etching solution is used for etching the object

The etching time of the ITO film was 50s, the etching temperature was 40 ℃, the etching result is shown in FIG. 5, the single-sided CD after etching was 0.0595um, and the ITO slope angle was 41 °.

Comparative example 3

An ITO etching solution for a TFT-LCD display screen comprises the following components in percentage by weight: 14 wt% sulfuric acid, 3 wt% ammonium sulfate, 0.1% surfactant, 0.05% defoamer, balance water.

FIG. 6 shows the results of etching Mo, Al and Cu with the etchant for 600s at 40 ℃ without any corrosion of the metal layers of Mo, Al and Cu by the etchant, and FIG. 7 shows the results of etching a Cu glass plate with the etchant for 600s at 40 ℃ with pitting corrosion on the surface.

The results, compared to the comparative examples, show that: the ITO etching solution disclosed by the invention is simple in process, moderate in acid concentration, excellent in etching performance on an ITO conductive film, moderate in etching rate, high in etching precision and free of residues, meanwhile, ammonium sulfate inorganic salt is used as an additive, the slope angle of the etched ITO can be adjusted, the slope angle of the ITO is larger and larger along with the increase of the content of ammonium sulfate, and the additive imidazole can ensure that the etching solution has excellent corrosion resistance effect on lower-layer metals Al, Mo and Cu, and can well meet the requirements of technical processes and manufacturing procedures.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims (4)

1. An ITO etching solution for a TFT-LCD display screen is characterized by comprising the following components in percentage by weight: 10 to 20 percent of sulfuric acid, 1 to 5 percent of additive, 0.05 to 0.5 percent of surfactant, 0.01 to 0.1 percent of defoaming agent and the balance of water, wherein the additive is a mixture of inorganic salt and organic matter.

2. The ITO etching solution for TFT-LCD display screen according to claim 1, wherein: the inorganic salt is selected from any one of ammonium acetate, ammonium sulfate, ammonium nitrate, potassium sulfate, monopotassium phosphate, potassium acetate and potassium citrate.

3. The ITO etching solution for TFT-LCD display screen according to claim 1, wherein: the organic matter is any one of methyl tetrazole, imidazole, 2-mercaptoimidazole, 2-mercapto-5-methylbenzimidazole, 1,2, 4-triazole, 4-amino-4H-1, 2, 4-triazole and benzotriazole.

4. A preparation method of ITO etching solution for a TFT-LCD display screen is characterized by comprising the following steps:

s1, adding a certain amount of high-purity water into the mixing kettle;

s2, adding a certain amount of concentrated sulfuric acid under the condition of continuous stirring, circulating for 2 hours, opening a cooling system, and cooling the sulfuric acid solution to 30 ℃;

s3, adding additives, surfactants and defoaming agents into the mixing kettle in proportion, and circulating for 30 min;

s4, filtering the mixed liquid by a 0.1-micron filter to obtain the ITO etching liquid.

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