KR102368373B1 - Etchant composition and manufacturing method of an array substrate for liquid crystal display - Google Patents

Abstract

The present invention relates to an etchant composition and a method of manufacturing an array substrate for a liquid crystal display. The etchant composition of the present invention includes a multilayer film and an amorphous silicon thin film (n+a-Si:H) including one or more films selected from a copper film and a copper alloy film, and one or more films selected from the group consisting of a titanium film and a titanium alloy film. ) or the metal oxide film can be collectively wet-etched, thereby reducing the overall process time and reducing cost.

Description

Etchant composition and method of manufacturing an array substrate for a liquid crystal display

The present invention relates to an etchant composition and a method of manufacturing an array substrate for a liquid crystal display.

A thin film transistor (TFT) is a typical electronic circuit that drives a semiconductor device and a flat panel display device. The TFT manufacturing process usually consists of forming a metal film as a material for a gate and data wiring on a substrate, forming a photoresist in a selective region of the metal film, and then etching the metal film using the photoresist as a mask.

Usually, a copper single film or a copper alloy film containing copper having high electrical conductivity and low resistance and a metal oxide film excellent in interfacial adhesion with these films are used as the material for the gate and data wiring. Recently, in order to improve TFT performance, a film containing indium oxide, zinc oxide, or a mixture thereof along with gallium oxide is used as a metal oxide film.

On the other hand, Korean Patent Application Laid-Open No. 2012-0138290 discloses a composition comprising at least one of persulfate, a fluorine compound, an inorganic acid, a cyclic amine compound, a sulfonic acid, an organic acid, and an organic salt as an etching solution for etching a copper/titanium film, and the remaining amount of water This is described. However, when the copper/titanium film is etched with the etching solution, the etch rate is high and the chronological property is improved while there are few gate disconnection defects or gate pattern defects, but the amorphous silicon thin film (n+a-Si:H) cannot be etched. There is a limitation in the process of having to go through a separate dry etching process.

Republic of Korea Patent Publication No. 2012-0138290

The present invention is to solve the problems of the prior art, a multilayer film and an amorphous silicon thin film including one or more films selected from a copper film and a copper alloy film, and one or more films selected from the group consisting of a titanium film and a titanium alloy film An object of the present invention is to provide an etchant composition capable of collectively wet-etching (n+a-Si:H) or a metal oxide film.

The present invention is a persulfate of 0.5 to 20% by weight, a fluorine compound 0.01 to 2.0% by weight, nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof 1 to 10% by weight, 0.5 to 5% by weight of a cyclic amine compound, acetic acid, citric acid, 0.1 to 10% by weight of at least one organic acid selected from the group consisting of malonic acid, lactic acid and malic acid and salts thereof, 0.1 to 3% by weight of sulfonic acid, 0.1 to 3% by weight of copper sulfate, and the balance of water; A multilayer film and an amorphous silicon thin film (n+a-Si:H) or metal oxide film including one or more films selected from a copper film and a copper alloy film, and one or more films selected from the group consisting of a titanium film and a titanium alloy film It provides an etchant composition, characterized in that wet etching.

In one embodiment, the persulfate is selected from the group consisting of potassium persulfate (K ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ) and ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ). It may be one or more types.

In another embodiment, the fluorine compound is ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, and potassium bifluoride ( potassium bifluoride) may be at least one selected from the group consisting of.

In another embodiment, the cyclic amine compound is aminotetrazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine. , pyrrole, pyrrolidine, and pyrroline may be at least one selected from the group consisting of.

In another embodiment, the metal oxide film may be an indium gallium zinc oxide (IGZO) film.

In addition, the present invention comprises the steps of: a) forming a gate electrode on a substrate;

b) forming a gate insulating layer on the substrate including the gate electrode;

c) forming a semiconductor layer (n+a-Si:H) on the gate insulating layer;

d) forming source/drain electrodes on the semiconductor layer; and

e) a method of manufacturing an array substrate for a liquid crystal display device comprising the step of forming a pixel electrode connected to the drain electrode,

Step a) or step d) provides a method of manufacturing an array substrate for a liquid crystal display, comprising the step of forming each electrode by etching with the etchant composition.

The etchant composition of the present invention includes a multilayer film and an amorphous silicon thin film (n+a-Si:H) including one or more films selected from a copper film and a copper alloy film, and one or more films selected from the group consisting of a titanium film and a titanium alloy film. ) or the metal oxide film can be collectively wet-etched, thereby reducing the overall process time and reducing cost.

1 shows the evaluation of etching characteristics according to an experimental example as an SEM result.
2 shows the calorific value results according to the experimental example.

The present invention relates to an etchant composition and a method of manufacturing an array substrate for a liquid crystal display.

Conventionally, the etchant composition for the copper film system was carried out through a wet etching process only up to the gate or S/D wiring, and the amorphous silicon thin film (n+a-Si:H), which is the lower film, was processed through a dry etching process. The present invention is intended to simplify the process, and includes at least one film selected from the group consisting of a copper film and a copper alloy film and at least one film selected from the group consisting of a titanium film and a titanium alloy film as it contains a certain amount of copper sulfate It is characterized in that the multilayer film and the amorphous silicon thin film (n+a-Si:H) or metal oxide film can be wet-etched at once.

Hereinafter, the present invention will be described in detail.

The present invention is a persulfate of 0.5 to 20% by weight, a fluorine compound 0.01 to 2.0% by weight, nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof 1 to 10% by weight, 0.5 to 5% by weight of a cyclic amine compound, acetic acid, citric acid, 0.1 to 10% by weight of at least one organic acid selected from the group consisting of malonic acid, lactic acid and malic acid and salts thereof, 0.1 to 3% by weight of sulfonic acid, 0.1 to 3% by weight of copper sulfate, and the balance of water; A multilayer film and an amorphous silicon thin film (n+a-Si:H) or metal oxide film including one or more films selected from a copper film and a copper alloy film, and one or more films selected from the group consisting of a titanium film and a titanium alloy film It provides an etchant composition, characterized in that wet etching.

The persulfate is contained in an amount of 0.5 to 20% by weight based on the total weight of the etchant composition. If the content of the persulfate is less than 0.5% by weight, the etching rate may decrease and sufficient etching may not be achieved, and the content of the persulfate is 20 When the weight % is exceeded, it is difficult to control the degree of etching because the etch rate is too fast, and thus the titanium film and the copper film may be overetched.

The persulfate may include, for example, potassium persulfate (K ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), or ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ). or a mixture of two or more of them.

The fluorine compound etches the titanium film, and removes residues generated by the etching. The fluorine compound is contained in an amount of 0.01 to 2.0% by weight based on the total weight of the etchant composition. If the content of the fluorine compound is less than about 0.01% by weight, it is difficult to etch titanium, and if it exceeds 2.0% by weight, the generation of residues due to the etching of titanium may increase. In addition, when the content of the fluorine compound exceeds 2.0 wt%, not only titanium but also the glass substrate on which titanium is laminated may be etched.

The fluorine compound is, for example, ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, or potassium bifluoride. (potassium bifluoride) may be included. In addition, the fluorine compound may include a mixture of two or more of them.

The nitric acid, sulfuric acid, phosphoric acid, perchloric acid or mixtures thereof are auxiliary oxidizing agents. The etching rate may be controlled according to the content of the nitric acid, sulfuric acid, phosphoric acid, perchloric acid, or a mixture thereof in the etchant composition. The nitric acid, sulfuric acid, phosphoric acid, perchloric acid, or a mixture thereof may react with copper ions in the etchant composition, thereby preventing an increase in the copper ions to prevent a decrease in the etch rate. The nitric acid, sulfuric acid, phosphoric acid, perchloric acid, or a mixture thereof is contained in an amount of 1 to 10% by weight based on the total weight of the etchant composition. If the content of nitric acid, sulfuric acid, phosphoric acid, perchloric acid, or a mixture thereof is less than 1% by weight, the etching rate decreases and a sufficient etching rate cannot be reached. or the photosensitive film may be peeled off. When the photosensitive layer is cracked or the photosensitive layer is peeled off, the titanium layer or the copper layer positioned below the photosensitive layer is excessively etched.

The cyclic amine compound is a corrosion inhibitor. The cyclic amine compound is contained in an amount of 0.5 to 5.0% by weight based on the total weight of the etchant composition. If the content of the cyclic amine compound is less than 0.5% by weight, the etching rate of the copper film increases and there is a risk of over-etching.

The cyclic amine compound is, for example, aminotetrazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, It may include pyrrole, pyrrolidine or pyrroline. Alternatively, the cyclic amine compound may include a mixture of two or more of them.

The at least one organic acid selected from the group consisting of acetic acid, citric acid, malonic acid, lactic acid, and malic acid and a salt thereof are contained in an amount of 0.1 to 10% by weight based on the total weight of the etchant composition. The organic acid increases the etching rate as the content in the etchant increases. The salt lowers the etching rate as the content of the etchant increases. In particular, the organic acid salt acts as a chelate to form a complex with copper ions in the etchant composition, thereby controlling the etching rate of copper. Accordingly, the etching rate can be controlled by adjusting the amounts of the organic acid and the organic acid salt in the etchant to an appropriate level.

When the content of at least one of the organic acid and the organic acid salt is less than 0.1% by weight, it is difficult to control the etching rate of copper and overetching may occur. lose Accordingly, the number of substrates to be processed is reduced.

The sulfonic acid serves to increase the performance of the copper treatment medium of the etchant. It acts as an auxiliary oxidizing agent for copper, and there is no change in the composition itself over time, and it plays a role in stabilizing the chemical solution. The sulfonic acid may be p-toluenesulfonic acid or methanesulfonic acid.

The copper sulfate accelerates the etching rate of the amorphous silicon thin film (n+a-Si:H) layer. The copper sulfate is contained in an amount of 0.1 to 3% by weight based on the total weight of the etchant composition. If the copper sulfate content is less than 0.1 wt%, the amorphous silicon thin film is not efficiently etched, and if it exceeds 3 wt%, there is a risk of over-etching.

In addition, the present invention comprises the steps of: a) forming a gate electrode on a substrate;

b) forming a gate insulating layer on the substrate including the gate electrode;

c) forming a semiconductor layer (n+a-Si:H) on the gate insulating layer;

d) forming source/drain electrodes on the semiconductor layer; and

e) a method of manufacturing an array substrate for a liquid crystal display device comprising the step of forming a pixel electrode connected to the drain electrode,

Step a) or step d) provides a method of manufacturing an array substrate for a liquid crystal display, comprising the step of forming each electrode by etching with the etchant composition. The array substrate for the liquid crystal display may be a thin film transistor (TFT) array substrate.

Hereinafter, the present invention will be described in more detail using Examples, Comparative Examples and Experimental Examples. However, the following Examples, Comparative Examples and Experimental Examples are provided to illustrate the present invention, and the present invention is not limited by the following Examples, Comparative Examples and Experimental Examples and may be variously modified and changed.

Example 1-5 and comparative example 1-2. etchant Preparation of the composition

An etchant composition was prepared according to the components and contents (unit: weight %) of Table 1 below.

division APS AF HNO ₃ ATZ p-TSA A.A. AcOH CuSO ₄ water Example 1 15 0.7 3 1.2 3.0 2.5 8.0 0.2 remaining amount Example 2 15 0.7 3 1.2 3.0 2.5 8.0 0.4 remaining amount Example 3 15 0.7 3 1.2 3.0 2.5 8.0 0.6 remaining amount Example 4 15 0.7 3 1.2 3.0 2.5 8.0 0.8 remaining amount Example 5 15 0.7 3 1.2 3.0 2.5 8.0 1.0 remaining amount Comparative Example 1 15 0.7 3 1.2 3.0 2.5 8.0 - remaining amount Comparative Example 2 15 0.7 3 1.2 0.0 2.5 8.0 - remaining amount

* APS: Ammonium persulfate

* AF: Ammonium fluoride

* ATZ: 5-aminotetrazole

* p-TSA: p-Toluene Sulfonic Acid

* A.A: Ammonium Acetate

* AcOH: Acetic acid

Experimental example . Etching Characteristics evaluation

(1) The etching characteristics of the samples in which the amorphous silicon thin film (n+a-Si:H) and the copper film were sequentially formed were evaluated with the etchant compositions of Examples 1 to 5 and Comparative Examples 1 and 2, and etching through SEM. The characteristics were observed and the results are shown in Table 2 and FIG. 1 .

division Etching rate (Å/sec) Example 1 4.6 Example 2 5.9 Example 3 8.5 Example 4 9.7 Example 5 11.7 Comparative Example 1 not etched Comparative Example 2 not etched

As shown in Table 2 and Figure 1, the etchant of Comparative Example 1 that does not contain copper sulfate (CuSO ₄ ) was not etched (measured 60 Å corresponds to the error range), whereas in Examples 1 to 5 It was shown that the etching rate of the N+A-Si layer increased as the content of copper sulfate increased.

In addition, in order to know the calorific value depending on whether p-TSA was included, the etchant compositions of Comparative Examples 1 and 2 were maintained at a constant temperature at 70° C., and Cu/Ti powder was added at 3000 rpm to measure the temperature change, and the results are shown in Table 3 and FIG. 2 .

division Max calorific value Comparative Example 1 82.8℃ Comparative Example 2 95.3℃

As shown in Table 3 and FIG. 2, it was confirmed that the etchant composition without p-TSA generated a large amount of heat when copper was dissolved.

(2) For the samples in which the IGZO film and the copper film were sequentially formed, the etching properties were evaluated with the etchant compositions of Examples 1 to 5 and Comparative Example 1, and the etching properties were observed through SEM, and the results are shown in Table 4. .

division Etching rate (Å/sec) Example 1 68 Example 2 76 Example 3 81 Example 4 83 Example 5 102 Comparative Example 1 26

As shown in Table 4, in the case of Examples 1 to 5, it was shown that the etching rate of the IGZO film increased as the content of copper sulfate increased.

Claims (6)

0.5 to 20% by weight of persulfate;
0.01 to 2.0 wt% of a fluorine compound;
1 to 10% by weight of nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof,
0.5 to 5% by weight of a cyclic amine compound;
0.1 to 10% by weight of at least one organic acid selected from the group consisting of acetic acid, citric acid, malonic acid, lactic acid and malic acid and salts thereof,
0.1 to 3% by weight of sulfonic acid;
0.4 to 1 weight percent copper sulfate, and
contains the remaining amount of water,
A multilayer film comprising at least one film selected from a copper film and a copper alloy film, and at least one film selected from the group consisting of a titanium film and a titanium alloy film, and
An etchant composition characterized in that an amorphous silicon thin film (n+a-Si:H) or a metal oxide film is wet-etched in one batch. The method according to claim 1,
The persulfate is at least one selected from the group consisting of potassium persulfate (K ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), and ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) The etchant composition. The method according to claim 1,
The fluorine compound is ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, and potassium bifluoride. At least one selected from the group consisting of, the etchant composition. The method according to claim 1,
The cyclic amine compound is aminotetrazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, and pyrrole. , pyrrolidine (pyrrolidine) and pyrroline (pyrroline) will at least one selected from the group consisting of, the etchant composition. The method according to claim 1,
The metal oxide film is an etchant composition, characterized in that the IGZO (Indium gallium zinc oxide) film. a) forming a gate electrode on the substrate;
b) forming a gate insulating layer on the substrate including the gate electrode;
c) forming a semiconductor layer (n+a-Si:H) on the gate insulating layer;
d) forming source/drain electrodes on the semiconductor layer; and
In the method of manufacturing an array substrate for a liquid crystal display device comprising the step of e) forming a pixel electrode connected to the drain electrode,
Step a) or step d) comprises the step of forming each electrode by etching with the etchant composition of claim 1, a method of manufacturing an array substrate for a liquid crystal display.

Images