TW201641671A - Etchant composition and method of manufacturing array substrate for liquid crystal display - Google Patents

Abstract

Disclosed are an etchant composition and a method of manufacturing an array substrate for a liquid crystal display, the etchant composition enabling one-step wet etching of an amorphous silicon thin layer (n+ a-Si:H) or a metal oxide layer, as well as a multilayer including at least one of a copper layer and a copper alloy layer and at least one of a titanium layer and a titanium alloy layer, thus reducing the total processing time and the manufacturing cost.

Description

Etchant composition and method of manufacturing array substrate for liquid crystal display Field of invention

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

Background of the invention

Electronic circuits for driving semiconductor devices or flat panel displays are typically exemplified by thin film transistors (TFTs). Fabrication of a TFT typically includes forming a metal layer for a gate line and a data line on a substrate, forming a photoresist on selected regions of the metal layer, and etching using the photoresist as a mask Metal layer.

Generally, materials for the gate lines and the data lines include: a copper single layer or a copper alloy layer containing copper having high electrical conductivity and low electrical resistance, and a metal oxide layer having excellent interface adhesion to the above copper layer. . In order to improve the performance of the TFT, the metal oxide layer is currently made of gallium oxide, indium oxide, zinc oxide or a mixture thereof.

In this regard, Korean Patent Application Publication No. 2012-0138290 discloses an etchant composition for etching a copper/titanium layer including persulfuric acid. At least one of a salt, a fluorine compound, an inorganic acid, a cyclic amine compound, a sulfonic acid, an organic acid, and an organic acid salt, and the balance of water. When the copper/titanium layer is etched using the above etchant, the gate lines or patterns are retained, and in addition, a high etching rate and a low change with time can be obtained, but an amorphous thin layer (n+a-Si: cannot be etched: H), disadvantageously incurring process limitations that require an additional dry etch process.

[reference list]

[Patent Literature]

Korean Patent Application Publication No. 2012-0138290

Summary of invention

Accordingly, the present invention has been made in mind the problems encountered in the related art, and an object of the present invention is to provide an etchant composition capable of laminating an amorphous tantalum layer (n+a-Si:H) or a metal oxide layer, And a multilayer one-step wet etching comprising at least one of a copper layer and a copper alloy layer and at least one of a titanium layer and a titanium alloy layer.

The present invention provides an etchant composition suitable for use in a multilayer comprising at least one of a copper layer and a copper alloy layer and at least one of a titanium layer and a titanium alloy layer, and an amorphous tantalum layer (n+a-Si:H) Or a one-step wet etching of the metal oxide layer, the etchant composition comprising: 0.5-20% by weight of persulfate, 0.01-2.0% by weight of fluorine compound, 1-10% by weight of nitric acid, sulfuric acid, phosphoric acid, high chlorine An acid or a mixture thereof, 0.5 to 5% by weight of a cyclic amine compound, 0.1 to 10% by weight, at least one selected from the group consisting of organic acids including acetic acid, citric acid, malonic acid, lactic acid, and malic acid, and salts thereof, 0.1 to 3 wt% Sulfonic acid, 0.1-3 wt% sulfur Copper acid, and the balance of water.

In an exemplary embodiment, the persulfate may include a 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 At least one of ₂ O ₈ )).

In another exemplary embodiment, the fluorine compound may include at least one selected from the group consisting of ammonium fluoride, sodium fluoride, potassium fluoride, ammonium hydrogen fluoride, sodium hydrogen fluoride, and potassium hydrogen fluoride.

In still another exemplary embodiment, the cyclic amine compound may include at least one selected from the group consisting of aminotetrazole, imidazole, hydrazine, hydrazine, pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, and pyrroline.

In still another exemplary embodiment, the metal oxide layer may be an indium gallium zinc oxide layer.

Further, the present invention provides a method of manufacturing an array substrate for a liquid crystal display, comprising: a) forming a gate electrode on a substrate; b) forming a gate insulating layer on a substrate including the gate electrode; c) Forming a semiconductor layer (n+a-Si:H) on the gate insulating layer; d) forming a source electrode and a drain electrode on the semiconductor layer; and e) forming a pixel electrode connected to the drain electrode, wherein a) Or d) includes etching using the above etchant composition, thereby forming a gate electrode, or a source electrode and a drain electrode.

According to the present invention, the etchant composition can be used in a thin layer of amorphous germanium (n+a-Si:H) or a metal oxide layer, and at least one of a copper layer and a copper alloy layer, and a titanium layer and a titanium alloy layer. At least one multi-layer one-step wet etch, thus reducing overall processing time and manufacturing costs.

The above and other objects, features, and advantages of the present invention will be more clearly understood from And Fig. 2 shows the evaluation results of the heat generated in the test examples.

Detailed description of the preferred embodiment

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

A conventional etchant composition for etching a copper base layer is used to make only a gate line or a source line/drain line wet-etched, while an amorphous thin layer (n+a-Si) placed under them :H) is dry etched. In the present invention, in order to simplify the process, the etchant composition contains a predetermined amount of copper sulfate, thereby enabling a thin layer of amorphous germanium (n+a-Si:H) or a metal oxide layer, and including a copper layer and a copper alloy layer. A multilayer one-step wet etching of at least one of the titanium layer and the titanium alloy layer.

Hereinafter, a detailed description of the present invention will be given.

The present invention discusses an etchant composition capable of laminating an amorphous tantalum layer (n+a-Si:H) or a metal oxide layer, and including at least one of a copper layer and a copper alloy layer, and a titanium layer and a titanium alloy layer One-step one-step wet etching of at least one of the etchant compositions comprising: 0.5-20% by weight of persulfate, 0.01-2.0% by weight of fluorine compound, 1-10% by weight of nitric acid, sulfuric acid, phosphoric acid, high chlorine An acid or a mixture thereof, 0.5 to 5% by weight of a cyclic amine compound, 0.1 to 10% by weight of an organic acid selected from the group consisting of acetic acid, citric acid, malonic acid, lactic acid and malic acid At least one of its salts, 0.1 to 3 wt% of sulfonic acid, 0.1 to 3 wt% of copper sulfate, and the balance of water.

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 amount of persulfate is less than 0.5% by weight, the etching rate may be lowered and thus sufficient etching may not be performed. On the other hand, if the amount of persulfate exceeds 20% by weight, the etching rate is too fast, thus making it difficult to control the degree of etching, thereby excessively etching the titanium layer and the copper layer.

Examples of the persulfate may include potassium persulfate (K ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ), and two of them. A mixture of more or more.

The fluorine compound acts to etch the titanium layer and remove residues that may be generated by 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 amount of the fluorine compound is less than about 0.01% by weight, it is difficult to etch titanium. On the other hand, if the amount exceeds 2.0% by weight, the residue due to etching of titanium may increase. Moreover, the use of the fluorine compound in an amount of more than 2.0% by weight may cause etching of a glass substrate on which titanium is formed and titanium.

Examples of the fluorine compound may include ammonium fluoride, sodium fluoride, potassium fluoride, ammonium hydrogen fluoride, sodium hydrogen fluoride, potassium hydrogen fluoride, and a mixture of two or more thereof.

Nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof is used as an auxiliary oxidizing agent. The etch rate can be controlled by varying the amount of nitric acid, sulfuric acid, phosphoric acid, perchloric acid, or a mixture thereof in the etchant composition. Nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof can be combined with copper ions in the etchant composition The reaction, thus preventing an increase in the amount of copper ions, prevents the etching rate from decreasing. Nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof is contained in an amount of from 1 to 10% by weight based on the total weight of the etchant composition. If the amount of nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof is less than 1% by weight, the etching rate may be reduced, thereby failing to reach a desired level. On the other hand, if the amount thereof exceeds 10% by weight, the photosensitive layer used in etching the metal layer may be cracked or peeled off. In the case where the photosensitive layer is cracked or peeled off, the titanium layer or the copper layer placed under the photosensitive layer may be excessively etched.

The cyclic amine compound is used as 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 combination group. If the amount of the cyclic amine compound is less than 0.5% by weight, the etching rate of the copper layer may increase, disadvantageously taking on the risk of over etching. On the other hand, if the amount exceeds 5.0% by weight, the etching rate of copper may be lowered, making it impossible to perform etching as desired.

Examples of the cyclic amine compound may include aminotetrazole, imidazole, hydrazine, hydrazine, pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, pyrroline, and a mixture of two or more thereof.

Also, at least one selected from the group consisting of organic acids including acetic acid, citric acid, malonic acid, lactic acid, and malic acid, and salts thereof, is contained in an amount of 0.1 to 10% by weight based on the total weight of the etchant composition. As the amount of organic acid in the etchant increases, the etch rate increases. The salt acts to reduce the etch rate in proportion to its amount in the etchant. In particular, the organic acid salt acts as a chelating agent to form a complex with copper ions in the etchant composition, thereby controlling the etch rate of copper. Therefore, when the amount of the organic acid and the organic acid salt in the etchant is appropriately adjusted, the etching rate can be controlled.

If the amount 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, disadvantageously causing over etching. On the other hand, if the amount thereof exceeds 10% by weight, the etching rate of copper may be reduced, and thus it is possible to increase the etching time, and therefore, the number of substrates that can be processed is reduced.

The sulfonic acid acts to increase the number of copper layers to be treated with an etchant. In addition, this component is used as an auxiliary oxidant for copper, does not change over time, and stabilizes the chemical. The sulfonic acid can be p-toluenesulfonic acid or methanesulfonic acid.

Copper sulfate acts to increase the etch rate of the amorphous tantalum layer (n+a-Si:H). 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 amount of copper sulfate is less than 0.1% by weight, the amorphous tantalum layer cannot be effectively etched. On the other hand, if the amount exceeds 3 wt%, there is a fear of over etching.

Further, the present invention relates to a method of manufacturing an array substrate for a liquid crystal display, comprising: a) forming a gate electrode on a substrate; b) forming a gate insulating layer on a substrate including the gate electrode; c) Forming a semiconductor layer (n+a-Si:H) on the gate insulating layer; d) forming a source electrode and a drain electrode on the semiconductor layer; and e) forming a pixel electrode connected to the drain electrode, wherein a) Or d) includes performing an etching process using the etchant composition as described above, thereby forming a gate electrode, or a source electrode and a drain electrode. The array substrate for a liquid crystal display may be a thin film transistor (TFT) array substrate.

The invention is described in detail by the following examples, comparative examples and test examples which are only for the purpose of illustrating the invention, but the invention is not limited to Examples, comparative examples and test examples are subject to various modifications and changes.

Examples 1-5 and Comparative Examples 1 and 2: Preparation of Etchant Compositions

An etchant composition was prepared using the amount (wt%) of the ingredients shown in Table 1 below.

Test example: Evaluation of etching characteristics

(1) Using the respective etchant compositions of Examples 1 to 5 and Comparative Examples 1 and 2, a sample in which an amorphous tantalum thin layer (n+a-Si:H) and a copper layer were sequentially formed was etched, and observed using SEM. Etching characteristics. The results are shown in Table 2 below and in Figure 1.

As is apparent from Table 2 and Fig. 1, when the etchant containing no copper sulfate (CuSO ₄ ) (the measured 60 Å corresponds to the error range) of Comparative Example 1 was used, etching did not occur. In Examples 1 to 5, as the amount of copper sulfate increased, the etching rate of the n+a-Si layer increased.

In order to monitor the heat generation in the presence or absence of p-TSA, the etchant compositions of Comparative Examples 1 and 2 were kept at a constant temperature of 70 ° C, then 3000 rpm of Cu/Ti powder was added, and the change in temperature was measured. The results are shown in Table 3 below and Figure 2.

As is apparent from Table 3 and Figure 2, the etchant composition without p-TSA produced a large amount of heat when copper was dissolved.

(2) Using the respective etchant compositions of Examples 1 to 5 and Comparative Example 1, A sample in which an indium gallium zinc oxide (IGZO) layer and a copper layer were formed in this order was etched, and the etching characteristics thereof were observed using SEM. The results are shown in Table 4 below.

As is apparent from Table 4, as the amount of copper sulfate increases, the etching rate of the indium gallium zinc oxide (IGZO) layer increases.

While the preferred embodiment of the present invention has been disclosed for purposes of illustration, it will be understood by those skilled in the art that various modifications, additions and substitutions are possible without departing from the scope and spirit of the invention as disclosed in the appended claims .

Claims (6)

An etchant composition suitable for one-step wet etching of a thin layer of amorphous germanium or a metal oxide layer, and a multilayer comprising at least one of a copper layer and a copper alloy layer and at least one of a titanium layer and a titanium alloy layer, The etchant composition comprises: 0.5-20% by weight of persulfate, 0.01-2.0% by weight of a fluorine compound, 1-10% by weight of nitric acid, sulfuric acid, phosphoric acid, perchloric acid or a mixture thereof, 0.5-5 wt% of a ring An amine compound, 0.1 to 10% by weight of at least one selected from the group consisting of organic acids including acetic acid, citric acid, malonic acid, lactic acid, and malic acid, and salts thereof, 0.1 to 3 wt% of sulfonic acid, 0.1 to 3 wt% of copper sulfate , and the balance of water. The etchant composition of claim 1, wherein the persulfate salt comprises at least one selected from the group consisting of potassium persulfate, sodium persulfate, and ammonium persulfate. The etchant composition of claim 1, wherein the fluorine compound comprises at least one selected from the group consisting of ammonium fluoride, sodium fluoride, potassium fluoride, ammonium hydrogen fluoride, sodium hydrogen fluoride, and potassium hydrogen fluoride. The etchant composition of claim 1, wherein the cyclic amine compound comprises at least one selected from the group consisting of aminotetrazole, imidazole, hydrazine, hydrazine, pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, and pyrroline. . The etchant composition of claim 1, wherein the metal oxide The layer is an indium gallium zinc oxide layer. A method of fabricating an array substrate for a liquid crystal display, comprising: a) forming a gate electrode on a substrate; b) forming a gate insulating layer on a substrate including the gate electrode; c) forming the gate insulating layer Forming a semiconductor layer thereon; d) forming a source electrode and a drain electrode on the semiconductor layer; and e) forming a pixel electrode connected to the drain electrode, wherein a) or d) includes using the etching according to claim 1. The composition is etched, thereby forming a gate electrode, or a source electrode and a drain electrode.