CN114085671B

CN114085671B - ITO (indium tin oxide) etching liquid for IPS (in-plane switching) type liquid crystal panel and preparation method thereof

Info

Publication number: CN114085671B
Application number: CN202111526270.2A
Authority: CN
Inventors: 操岳峰; 王维康; 黄德新
Original assignee: Hefei Zhongju Hecheng Electronic Material Co ltd
Current assignee: Hefei Zhongju Hecheng Electronic Material Co ltd
Priority date: 2021-12-14
Filing date: 2021-12-14
Publication date: 2022-09-02
Anticipated expiration: 2041-12-14
Also published as: CN114085671A

Abstract

The invention discloses an ITO (indium tin oxide) etching solution for an IPS (in-plane switching) type liquid crystal panel, which relates to the technical field of ITO etching solutions and mainly comprises the following raw materials in percentage by weight: 8 to 27 percent of hydrochloric acid, 3 to 12 percent of acetic acid, 0.05 to 5 percent of ITO etching rate regulator, 0.02 to 1 percent of surfactant and the balance of water; the ITO etching rate regulator is one or more of chromate, molybdate, tungstate, vanadate, nitrite and borate, and the surfactant is a thio surfactant. The invention has the beneficial effects that: the ITO etching liquid has the advantages of mild etching rate, easily controlled etching process, improved etching precision within +/-0.5 um, effectively reduced surface tension of the etching liquid and the ITO, reduced aggregation of etched products on the surface of the ITO, low tension, strong wetting force, more uniform etched lines, and more complete and clean etching.

Description

ITO (indium tin oxide) etching liquid for IPS (in-plane switching) type liquid crystal panel and preparation method thereof

Technical Field

The invention relates to the technical field of ITO (indium tin oxide) etching liquid, in particular to ITO etching liquid for an IPS (in-plane switching) type liquid crystal panel and a preparation method thereof.

Background

The IPS mode liquid crystal panel is currently the mainstream liquid crystal panel type, and the IPS mode liquid crystal panel becomes an ideal display technology of the TFT-LCD for the TV due to its advantages of large viewing angle, fine color, and the like. The matching and orientation of the liquid crystal molecules and the PI orientation film can be efficiently and accurately evaluated by Minicell. The electricity is mainly characterized by Ion intensity, VHR, RDC and dielectric constant, and the optics is mainly analyzed by phase difference, pretilt angle, twist angle and V-T curve. The ITO capacitance graph with complete and uniform lines is a necessary condition for ensuring accurate comparison of the minicell performance.

In order to prepare a desired electrode pattern, an ITO conductive film is etched, and the etching solution composition of the patent application No. 201210206045.5 includes hydrochloric acid, nitric acid, pure water and a surfactant, dodecylbenzenesulfonic acid, and the etching solution uses aqua regia, and the etching process is severe, and it is difficult to precisely control the etching precision and the etching time.

The patent with the publication number of CN103805203B provides 15-25% of formula hydrochloric acid, 1-10% of acetic acid, 0.5-5% of copper corrosion inhibitor, 5-500 ppm of surfactant and the balance of deionized water, wherein the additive is copper corrosion inhibitor which only inhibits the etching of surface copper wires but cannot adjust the etching rate of ITO. The etching mode used in the patent is a spraying type, the equipment is huge in cost, the etching error of the IPS type ITO is more than 5 microns, the precision required by the IPS type ITO pattern is up to +/-0.5 microns, the line yield is 100 percent, the existing formula is rapid in etching, the application range is small, and the etching precision is difficult to control.

Disclosure of Invention

The invention aims to solve the technical problems that in the prior art, the ITO etching solution is rapid in etching, small in using range and difficult in control of etching precision, and provides the ITO etching solution for the IPS liquid crystal panel and the preparation method thereof.

The invention solves the technical problems through the following technical means:

an ITO etching solution for an IPS liquid crystal panel is mainly composed of the following raw materials in percentage by weight: 8 to 27 percent of hydrochloric acid, 3 to 12 percent of acetic acid, 0.05 to 5 percent of ITO etching rate regulator, 0.02 to 1 percent of surfactant and the balance of water;

the ITO etching rate regulator is one or more of chromate, molybdate, tungstate, vanadate, nitrite and borate, and the surfactant is a thio surfactant.

Has the advantages that: the ITO etching liquid has the advantages of mild etching rate, easily controlled etching process, improved etching precision within +/-0.5 um, effectively reduced surface tension of the etching liquid and the ITO, reduced aggregation of etched products on the surface of the ITO, low tension, strong wetting force, more uniform etched lines, and more complete and clean etching.

Preferably, the chromate is sodium chromate, the molybdate is sodium molybdate, the tungstate is sodium tungstate, the vanadate is sodium vanadate, the nitrite is sodium nitrite, and the borate is sodium borate.

Preferably, the thiosurfactant is one or more of sodium thiosulfate, sodium thiosulfate and sodium dodecyl benzene sulfonate.

Preferably, the ITO etching solution for the IPS liquid crystal panel mainly comprises the following raw materials in percentage by weight: 13 wt% of hydrochloric acid, 5wt% of acetic acid, 0.08wt% of sodium borate, 0.05wt% of sodium thiosulfate and the balance of pure water.

Has the advantages that: under the proportioning condition, the etching is complete.

The preparation method of the ITO etching solution for the IPS liquid crystal panel comprises the following steps:

s1, adding a certain amount of pure water into the stirring kettle at normal temperature and normal pressure;

s2, opening a cooling system to ensure that the temperature is lower than 25 ℃, stirring, adding a certain amount of concentrated hydrochloric acid, uniformly stirring, keeping the temperature constant, adding a certain amount of acetic acid, and stirring;

s3, respectively adding an ITO etching rate regulator and a surfactant, and stirring;

s4, mixing uniformly, and filtering by using a filter to remove impurities.

Has the advantages that: the etching liquid in the invention takes hydrochloric acid and acetic acid as main components, the production process is simple, and the etching volatility is small below 25 ℃; the etching rate is mild, and the etching process is changeed and is controlled, and the sculpture precision improves to within 0.5um, can effectively reduce the surface tension of etching solution and ITO simultaneously, reduces the gathering of formation on the ITO surface after the etching, and tension is low, the wetting power is strong, the etching lines is more even, and the etching is more abundant thoroughly clean.

Preferably, the stirring speed in step S2 is 150 rpm.

Preferably, in the step S4, the impurities are removed by filtering with 0.3 μm, 0.2 μm and 0.1 μm filters, respectively.

Preferably, the time for stirring twice in step S1 is 30 min.

Preferably, the stirring time in the step S3 is 30 min.

The invention has the advantages that: the ITO etching solution has the advantages of mild etching rate, easier control of etching process, improvement of etching precision to be within +/-0.5 um, effective reduction of surface tension of the etching solution and the ITO, reduction of aggregation of products after etching on the surface of the ITO, low tension, strong wetting force, more uniform etching lines, and more complete and clean etching.

The etching liquid in the invention takes hydrochloric acid and acetic acid as main components, the production process is simple, and the etching volatility is small at 23 ℃; the etching rate is mild, and the etching process is changeed and is controlled, and the sculpture precision improves to within 0.5um, can effectively reduce the surface tension of etching solution and ITO simultaneously, reduces the gathering of formation on the ITO surface after the etching, and tension is low, the wetting power is strong, the etching lines is more even, and the etching is more abundant thoroughly clean.

Drawings

FIG. 1 is a diagram showing an etched ITO pattern according to example 1 of the present invention;

FIG. 2 is a graph of etched ITO from comparative example 1 of the present invention;

FIG. 3 is a graph of etched ITO from comparative example 2 of the present invention;

FIG. 4 is a graph of etched ITO of comparative example 3 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all 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.

The test materials and reagents used in the following examples, etc., are commercially available unless otherwise specified.

The specific techniques or conditions not specified in the examples can be performed according to the techniques or conditions described in the literature in the field or according to the product specification.

Example 1

The ITO etching solution for the IPS liquid crystal panel comprises the following raw materials in percentage by weight: 13 wt% of hydrochloric acid, 5wt% of acetic acid, 0.08wt% of sodium borate, 0.05wt% of sodium thiosulfate and the balance of pure water. Wherein, the hydrochloric acid 13 percent means that the raw material is concentrated hydrochloric acid, and the mass ratio of the raw material in the etching solution is 13 percent.

The preparation method of the ITO etching liquid comprises the following steps:

s2, opening a cooling system, keeping the temperature at 23 ℃, rotating at 150rpm, adding quantitative hydrochloric acid, stirring for 30min uniformly, keeping the temperature constant, adding quantitative acetic acid, and stirring for 30 min;

s3, respectively adding sodium borate and sodium thiosulfate, and stirring for 30 min;

s4, mixing uniformly, and filtering by using filters with the particle size of 0.3 mu m, 0.2 mu m and 0.1 mu m respectively to remove impurities.

Example 2

This embodiment is different from embodiment 1 in that: the ITO etching solution for the IPS liquid crystal panel comprises the following raw materials in percentage by weight: 8wt% of hydrochloric acid, 12 wt% of acetic acid, 0.05wt% of sodium borate, 0.02wt% of sodium thiosulfate and the balance of pure water.

Example 3

This embodiment is different from embodiment 1 in that: the ITO etching solution for the IPS liquid crystal panel comprises the following raw materials in percentage by weight: 8wt% of hydrochloric acid, 12 wt% of acetic acid, 0.05wt% of sodium borate, 1wt% of sodium thiosulfate and the balance of pure water.

Example 4

This embodiment is different from embodiment 1 in that: the ITO etching solution for the IPS liquid crystal panel comprises the following raw materials in percentage by weight: 27 wt% of hydrochloric acid, 3 wt% of acetic acid, 5wt% of sodium thiosulfate, 0.02wt% of sodium thiosulfate and the balance of pure water.

Comparative example 1

This comparative example differs from example 1 in that: the ITO etching solution for the IPS liquid crystal panel comprises the following raw materials in percentage by weight: 12 wt% of hydrochloric acid, 5wt% of acetic acid, 0.08wt% of sodium thiosulfate, 0.01wt% of sodium thiosulfate and the balance of pure water.

Comparative example 2

This comparative example differs from example 1 in that: the ITO etching solution for the IPS liquid crystal panel comprises the following raw materials in percentage by weight: 15 wt% of hydrochloric acid, 5wt% of acetic acid, 0.05wt% of sodium thiosulfate and the balance of pure water.

Comparative example 3

The etching solution disclosed in patent with publication number CN103805203B is adopted, and consists of the following raw materials in mass concentration: 17wt% of hydrochloric acid, 2wt% of acetic acid, 1wt% of hexamethylenediamine, HA-1150 ppm of surfactant and the balance of deionized water, and soaking, spraying and etching for 120s at 40 ℃. SEM showed that the width required for etching was not reached and that there was a large amount of ITO particle residue. FIG. 4 is a diagram of the etched ITO pattern.

The object of etching was an ITO glass with a thickness of 700 a, and on the ITO was a photoresist with an IPS pattern, the photoresist width was 10 μm, and the photoresist pitch was 10 μm. The line pitch after etching was required to be 8 μm and the line width to be 12 μm.

Etching is carried out for 30s at 23 ℃ by using the etching solution in the embodiment 1, then the photoresist is removed by using a stripping solution, the resistance test of an ohmmeter shows infinite resistance to show complete etching, the line width of the ITO is 7.93 mu m under SEM observation, the line distance is 11.90 mu m, and the graph of the etched ITO is shown in figure 1.

The etching solution in comparative example 1 is used for etching for 30s at 23 ℃, then the photoresist is removed by using the stripping solution, resistance is tested, SEM shows that etching is not thorough, and a large amount of residual ITO exists between lines. FIG. 2 is a diagram of the etched ITO pattern.

After etching at 23 ℃ for 30s using the etching solution of comparative example 2 and then removing the photoresist with a stripping solution, resistance was measured and SEM showed that etching was excessive and that a large amount of ITO remained. FIG. 3 is a diagram of the etched ITO pattern.

Etching was performed at 40 ℃ for 120s using the etching solution of comparative example 3, and then the photoresist was removed using a stripping solution, SEM showed that the width required for etching was not reached and a large amount of ITO particles remained. FIG. 4 is a diagram of the etched ITO pattern.

The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. An ITO etching solution for an IPS type liquid crystal panel is characterized in that: the material mainly comprises the following raw materials in percentage by weight: 8-27% of hydrochloric acid, 3-12% of acetic acid, 0.05-5% of an ITO (indium tin oxide) etching rate regulator, 0.02-1% of a surfactant and the balance of water, wherein the ITO etching rate regulator is sodium borate, and the surfactant is sodium thiosulfate.

2. The ITO etching solution for IPS type liquid crystal panel of claim 1, wherein: the ITO etching solution for the IPS liquid crystal panel mainly comprises the following raw materials in percentage by weight: 13 wt% of hydrochloric acid, 5wt% of acetic acid, 0.08wt% of sodium borate, 0.05wt% of sodium thiosulfate and the balance of pure water.

3. A method of preparing the ITO etching solution for the IPS mode liquid crystal panel as set forth in any one of claims 1 to 2, characterized in that: the method comprises the following steps:

s4, mixing uniformly, and filtering by using a filter to remove impurities.

4. The method of preparing an ITO etching solution for an IPS type liquid crystal panel as claimed in claim 3, wherein: the stirring speed in step S2 was 150 rpm.

5. The method of preparing an ITO etching solution for an IPS type liquid crystal panel as claimed in claim 3, wherein: in the step S4, the impurities are removed by filtering with 0.3 μm, 0.2 μm and 0.1 μm filters respectively.

6. The method of preparing an ITO etching solution for an IPS type liquid crystal panel as claimed in claim 3, wherein: the time for stirring twice in the step S1 is 30 min.

7. The method of preparing an ITO etching solution for an IPS type liquid crystal panel as claimed in claim 3, wherein: the stirring time in the step S3 is 30 min.