TW201420812A - Etchant composition, method for forming metal pattern, and method for fabricating array substrate - Google Patents

Abstract

The present invention discloses an etchant composition, a method of forming a metal pattern, and a method of fabricating an array substrate for a liquid crystal display. The etchant composition is used for a single layer film of silver (Ag) or a silver alloy or a multilayer film composed of the single layer film and an indium oxide film, the etchant composition comprising nitric acid, sulfuric acid, three Iron salt and water.

Description

Etchant composition, method for forming metal pattern, and method for fabricating array substrate

The present application relates to an etchant composition for a single layer film of silver (Ag) or a silver alloy or a multilayer film composed of the single layer film and an indium oxide film; A method of forming a metal pattern using the etchant composition; and a method of fabricating an array substrate for a liquid crystal display using the etchant composition.

A liquid crystal display is one of the most widely used flat panel displays, and includes two substrates each provided with an electrode, and a liquid crystal layer interposed between the two substrates. A liquid crystal display is a display device that controls light propagation by applying a voltage to an electrode thereby rearranging liquid crystal molecules in the liquid crystal layer.

Currently, in liquid crystal displays, liquid crystal displays are generally used, wherein each liquid crystal display is provided with two substrates each provided with an electric field generating electrode. Further, a commonly used liquid crystal display is such that a plurality of pixel electrodes are arranged in a matrix array on one substrate, and the other substrate is entirely covered with a common electrode. In such a liquid crystal display, an image is displayed by applying a voltage to each of the pixel electrodes. To this end, such a liquid crystal display is configured such that a thin film transistor is connected to each of the pixel electrodes, and a gate line and a data line are formed on the substrate, wherein the thin film transistor is for converting a voltage applied to each of the pixel electrodes A three-terminal device, a gate line for transmitting a signal for controlling a thin film transistor, and a data line for transmitting a voltage to be applied to each pixel electrode.

At the same time, as the display area of the liquid crystal display increases, the gate lines and data lines connected to the thin film transistor (TFT) become longer, thereby increasing the resistance of the wiring. For this reason, when chromium (Cr), molybdenum (Mo), aluminum (Al), or an alloy thereof is used in the gate wire and the data line, it is difficult to increase the size of the flat panel display and it is difficult to achieve high resolution of the flat panel display. Therefore, in order to solve the problem of signal delay caused by an increase in resistance, it is necessary to manufacture a gate line and a data line with a material having a low resistivity.

For this purpose, efforts have been made to increase the size of flat panel displays, achieve high resolution of flat panel displays, and reduce power consumption by using silver (Ag) films, silver alloy films, or multiple layers including silver films and silver alloy films. Membranes (these films have lower resistivity (resistance coefficient: about 1.59 μΩ·cm) than other metal films and higher brightness than other metal films) are applied to the electrodes of the color filter, the wiring of the LCD, and the reflecting plate. As part of this effort, etchants suitable for use in these materials have been developed.

Currently, an etchant comprising phosphoric acid and hydrogen peroxide is used for this purpose. For example, Korean Patent Application 2011-0077734 discloses an etchant composition comprising sulfuric acid, phosphoric acid, a weak acid, and hydrogen peroxide. However, the etchant composition is likely to fail after being stored at room temperature for one month or longer. This is because hydrogen peroxide and persulfate cannot be stably maintained for one month or longer.

Therefore, there is a need to develop an etchant that does not have such long-term storage problems.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to provide an etchant composition which can exhibit silver (Ag) or a silver alloy even after long-term storage. Good etching performance of a single layer film or a multilayer film composed of the single layer film and an indium oxide film; and another object of the present invention is to provide a method for forming a metal pattern using the etching composition and to utilize the same Etchant Composition A method of fabricating an array substrate for a liquid crystal display.

In order to achieve the above object, an aspect of the present invention provides an etchant composition for use in a single layer film of silver (Ag) or a silver alloy or by A multilayer film comprising a monolayer film and an indium oxide film, the etchant composition comprising nitric acid, sulfuric acid, ferric salt, and water.

Another aspect of the present invention provides a method of forming a metal pattern, the method comprising the steps of: (i) forming a single layer film selected from silver or a silver alloy on a substrate, and forming the single layer film and indium oxide from the substrate At least one film of the multilayer film; and (ii) etching the at least one film with the etchant composition.

Yet another aspect of the present invention is to provide a method of fabricating an array substrate for a liquid crystal display, the method comprising the steps of: a) forming a gate on a substrate; b) forming a gate insulating on a substrate including the gate a layer; a) forming a semiconductor layer on the gate insulating layer; d) forming a source and a drain on the semiconductor layer; and e) forming a pixel electrode to be connected to the drain, wherein the step At least one of steps a), d) and e) comprises the steps of: forming a single layer film selected from the group consisting of silver or a silver alloy, and at least one film of a multilayer film composed of the single layer film and an indium oxide film; The at least one film is etched using the etchant composition to form individual electrodes.

The above and other objects, features and advantages of the present invention will become more apparent from the aspects of the accompanying drawings in which <RTIgt; The film was etched using the etchant composition of Example 1, wherein the etchant composition was stored for 1 day after preparation; FIG. 2 is a SEM photograph showing the surface of the substrate on which the substrate was utilized. The etchant composition of Example 1 was subjected to etching a three-layer film of a-ITO-Ag-ITO, and the photoresist was peeled off, wherein the etchant composition was stored for one day after preparation; FIG. 3 is a view SEM photograph of a three-layer film of a-ITO-Ag-ITO, which was etched using the etchant composition of Example 1, wherein the etchant composition was stored for 30 days after preparation; To show an SEM photograph of the surface of the substrate, an a-ITO-Ag-ITO three-layer film was etched on the substrate using the etchant composition of Example 1, and peeled off. a photoresist in which the etchant composition was stored for 30 days after preparation; FIG. 5 is a SEM photograph showing a three-layer film of a-ITO-Ag-ITO using the etching of Comparative Example 1. The composition was etched, wherein the etchant composition was stored for 1 day after preparation; FIG. 6 is a SEM photograph showing the surface of the substrate on which the etchant composition of Comparative Example 1 was used. The a-ITO-Ag-ITO three-layer film was etched and the photoresist was peeled off, wherein the etchant composition was stored for one day after preparation; FIG. 7 shows a-ITO-Ag-ITO three. SEM photograph of the layer film, which was etched using the etchant composition of Comparative Example 1, wherein the etchant composition was stored for 30 days after preparation; and FIG. 8 is a view showing the surface of the substrate SEM photograph, on the substrate, an a-ITO-Ag-ITO three-layer film was etched using the etchant composition of Comparative Example 1, and the photoresist was peeled off, wherein the etchant composition was stored after preparation It took 30 days.

Hereinafter, the present invention will be described in detail.

The present invention provides an etchant composition for a single layer film of silver or a silver alloy or a multilayer film composed of the single layer film and an indium oxide film, the etchant composition Contains nitric acid, sulfuric acid, ferric salt and water.

The etchant composition of the present invention is characterized in that the etchant composition is capable of simultaneously etching an alloy single layer film of silver or silver or a multilayer film composed of the single layer film and an indium oxide film.

In the present invention, the multilayer film composed of a single layer film of silver or a silver alloy and an indium oxide film may be a two-layer film of an indium oxide film/silver film, an indium oxide film/silver film/indium oxide film. Three-layer film and so on. Further, the indium oxide may be indium tin oxide (ITO), indium zinc oxide (IZO), or the like.

In the etchant composition of the present invention, nitric acid used as a main oxidizing agent component is used for wet etching of a silver film and an indium oxide film by oxidizing a silver film and an indium oxide film. The amount of nitric acid is 2.0 to 4.0 wt% based on the total weight of the etchant composition. When nitric acid When the amount is less than 2.0 wt%, the etching rate of the silver film is lowered, and the etching profile of the silver film is deteriorated. Further, when the amount of nitric acid exceeds 4.0 wt%, in the case of etching a three-layer film of an indium oxide film/silver film/indium oxide film, the surface of the silver film is caused by excessive etching of the indium oxide film The layer is exposed, causing the problem that silver is separated from the surface of the substrate and then re-adsorbed onto the substrate by heat treatment of a subsequent process.

In the etchant composition of the present invention, 4.0 to 6.0% by weight of sulfuric acid serving as an auxiliary oxide solvent is added based on the total weight of the etchant composition. When the amount of sulfuric acid added exceeds 6.0 wt%, the etching length is increased due to the high etching rate, thereby hindering the process. Further, when the amount of sulfuric acid added is less than 4.0% by weight, it is not easy to etch the silver film.

In the etchant composition of the present invention, a ferric salt used as a main oxidizing agent component is used for wet etching of a silver film and an indium oxide film by oxidizing a silver film and an indium oxide film. The amount of the ferric salt is 0.1 to 2.0 wt%, and preferably 0.1 to 0.4 wt%, based on the total weight of the etchant composition. When the amount of the trivalent iron salt is less than 0.1 wt%, the etching rate of the silver film is lowered, and the etching profile of the silver film is deteriorated. Further, when the amount of the trivalent iron salt exceeds 2.0 wt%, in the case of etching the three-layer film of the indium oxide film/silver film/indium oxide film, silver is excessively etched due to the indium oxide film The surface layer of the film is exposed, causing the problem that silver is separated from the substrate surface and then re-adsorbed onto the substrate by heat treatment of a subsequent process.

In the etchant composition of the present invention, water is not particularly limited, but deionized water is preferred. Specifically, deionized water having a resistivity of 18 MΩ/cm or more (i.e., the degree of removal of ions from water) is more preferable.

In addition to the above ingredients, the above etchant composition may further include a conventional additive. A surfactant, a chelating agent or an anticorrosive agent can be used as an additive.

In the etchant composition of the present invention, nitric acid, sulfuric acid and ferric salt can be produced by a conventionally known method. In particular, it is preferred that they have a purity for a semiconductor process.

Moreover, the present invention provides a method of forming a metal pattern, the method comprising The following steps: (i) forming at least one film of a single layer film selected from silver or a silver alloy and a multilayer film composed of the single layer film and an indium oxide film on a substrate; and (ii) etching using the present invention The agent composition etches the at least one film.

In the method of forming a metal pattern according to the present invention, the step (i) comprises the steps of: providing a substrate; and forming a single layer film selected from silver or a silver alloy on the substrate and from the single layer film and indium oxide At least one film of a multilayer film composed of a film.

For the substrate, a wafer, a glass substrate, a stainless steel substrate, a plastic substrate or a quartz substrate which can be cleaned by a conventional method can be used. The process of forming a single layer film of silver or a silver alloy or a multilayer film composed of the single layer film and an indium oxide film on the substrate can be carried out by various methods known to those skilled in the art. These films are preferably formed by vacuum deposition or sputtering.

In the step (ii), a photoresist is formed on at least one of the films formed in the step (i), the formed photoresist is selectively exposed by a mask; the exposed photoresist is post-baked; The post-baked photoresist is developed to form a photoresist pattern.

The at least one film provided with the photoresist pattern is etched using the etchant composition of the present invention, thereby completing the metal pattern.

Further, the present invention provides a method of manufacturing an array substrate for a liquid crystal display, the method comprising the steps of: a) forming a gate on a substrate; b) forming a gate insulating layer on a substrate including the gate; Forming a semiconductor layer on the gate insulating layer; d) forming a source and a drain on the semiconductor layer; and e) forming a pixel electrode to be connected to the drain, wherein steps a), d) At least one of the steps of e) and e) includes the steps of: forming a single layer film selected from the group consisting of silver or a silver alloy, and at least one film of the multilayer film composed of the single layer film and the indium oxide film; and engraving using the present invention The etchant composition etches the at least one film to form individual electrodes.

The array substrate for a liquid crystal display may be an array substrate for a thin film transistor.

In the method of manufacturing an array substrate for a liquid crystal display according to the present invention, the step a) comprises the steps of: a1) depositing on the substrate by vapor deposition or sputtering. a single layer film selected from silver or a silver alloy and at least one of the multilayer film composed of the single layer film and the indium oxide film; and a2) etching the at least one type using the etchant composition of the present invention The film forms a gate. Herein, the process of forming the at least one film is not limited thereto.

In the method of the array substrate for a liquid crystal display manufactured according to the present invention, in step b), the silicon nitride (SiN _x) is deposited on the gate electrode is formed on the substrate to form the gate insulating layer. Herein, the material used in forming the gate insulating layer is not limited to germanium nitride (SiN _x ), and the gate insulating layer may be formed using any one selected from a plurality of inorganic insulating materials containing germanium dioxide (SiO ₂ ). .

In the method of manufacturing an array substrate for a liquid crystal display according to the present invention, in step c), a semiconductor layer is formed on the gate insulating layer by chemical vapor deposition (CVD). That is, an active layer and an ohmic contact layer are sequentially formed, and then the active layer and the ohmic contact layer are patterned by dry etching. Herein, the active layer is usually formed of pure amorphous germanium (a-Si:H), and the ohmic contact layer is usually formed of amorphous germanium (n+ a-Si:H) containing impurities. These active layers and ohmic contact layers may be formed by chemical vapor deposition, but the method of forming these layers is not limited thereto.

In the method of manufacturing an array substrate for a liquid crystal display according to the present invention, the step d) comprises the steps of: d1) forming a source and a drain on the semiconductor layer; and d2) forming an insulating on the source and the drain Floor. In the step d1), at least one of a single layer film selected from silver or a silver alloy and a multilayer film composed of the single layer film and the indium oxide film is deposited on the ohmic contact layer by sputtering, and then utilized The etchant composition of the present invention etches the at least one film to form a source and a drain. Herein, the method of forming at least one film on the substrate is not limited to the above method. In the step d2), an inorganic insulating material containing cerium nitride (SiN _x ) and cerium oxide (SiO ₂ ) or an organic insulating material containing benzoquinone cyclobutene (BCB) and an acrylic resin is used on the source and the drain. A single layer of insulating layer or a double layer of insulating layer is formed. Herein, the raw material of the insulating layer is not limited to the above raw materials.

In the method of manufacturing an array substrate for a liquid crystal display according to the present invention, In step e), a pixel electrode to be connected to the drain is formed. For example, a single layer film selected from silver or a silver alloy and at least one of the multilayer film composed of the single layer film and the indium oxide film are deposited by sputtering, and then the etchant composition of the present invention is used. The at least one film is etched to form a pixel electrode. The method of depositing the indium oxide film is not limited to sputtering.

Hereinafter, the present invention will be described in further detail with reference to the following examples. However, these examples are for explaining the present invention, and the scope of the present invention is not limited thereto.

Preparation of etchant composition

An etchant composition having a weight of 10 kg was prepared by the composition ratio shown in Table 1 below.

Evaluation of etching characteristics

A three-layer film of a-ITO/Ag/a-ITO was formed on the substrate, and then cut into a size of 10 × 10 mm using a diamond cutter to prepare a test sample.

The etchant compositions of Examples 1 to 3 and Comparative Examples 1 to 3 which were stored for one day after preparation were introduced into an injection type etching test apparatus (manufactured by SEMES), and then heated to 38 ± based on a set temperature of 38 ° C. 0.1 ° C, then etched the test sample Cheng. The etching process is performed as follows: based on endpoint detection (EPD), the total etch time includes 50% over etch time. Further, the etching process of the test sample was carried out in the same manner as described above using the etchant compositions of Examples 1 to 3 and Comparative Examples 1 to 3 which were stored for 30 days after preparation.

The etched test sample was taken out of the test apparatus, rinsed with deionized water, then dried using a hot air dryer, and then the photoresist was removed from the test sample using a photoresist (PR) stripper. Thereafter, a scanning electron microscope (SEM) (S-4700, manufactured by Hitachi, Inc.) was used to evaluate the etching characteristics of the test sample, such as the side etching rate.

The test results of the etching characteristics are shown in Table 2 below.

As shown in Table 2 above, when the a-ITO/Ag/a-ITO substrate was etched using the etchant composition of Example 1, the etching of the etchant composition of Example 1 after one day of storage was performed. The etch rate of the etchant composition of Example 1 after storage for 30 days was reduced by 26% compared to the rate. In contrast, when the a-ITO/Ag/a-ITO substrate was etched using the etchant composition of Comparative Example 1, the etching rate of the etchant composition of Comparative Example 1 after one day of storage was The etching rate of the etchant composition of Comparative Example 1 after storage for 30 days was reduced by 47%. Therefore, it can be determined that the conventional etchant composition The long-term storage property of the etchant composition of the present invention is greatly improved as compared with the long-term storage property.

Further, referring to FIGS. 1 to 8, it can be confirmed that the etching property of the etchant composition of Example 1 is good as compared with the etching property of the etchant composition of Comparative Example 1.

Beneficial effect

As described above, the etchant composition of the present invention can exhibit a single layer film for silver (Ag) or a silver alloy or a multilayer film composed of the single layer film and an indium oxide film even after long-term storage. Good etch characteristics. Therefore, the etchant composition can be used in an etching process without a problem of long-term storage.

While a preferred embodiment of the present invention has been disclosed for the purpose of illustration, it will be understood by those skilled in the art that various modifications and changes may be made without departing from the scope and spirit of the invention disclosed in the appended claims. And alternatives are possible.

Claims (8)

An etchant composition for a single layer film of silver or a silver alloy or a multilayer film composed of the single layer film and an indium oxide film, the etchant composition comprising nitric acid , sulfuric acid, ferric salt and water. The etchant composition according to claim 1, wherein the etchant composition comprises: 2 to 4.0 wt% of nitric acid; 4.0 to 6.0 wt%, based on the total weight of the etchant composition. Sulfuric acid; 0.1 to 2.0 wt% of ferric salt; and the balance of water. The etchant composition of claim 1, wherein the water is deionized water. The etchant composition according to claim 1, further comprising at least one additive selected from the group consisting of a surfactant, a chelating agent, and an anticorrosive agent. A method of forming a metal pattern, the method comprising the steps of: (i) forming at least one of a single layer film selected from silver or a silver alloy and a multilayer film composed of the single layer film and an indium oxide film on a substrate. The film; and (ii) etching the at least one film with the etchant composition of any one of claims 1 to 4. The method of claim 5, further comprising the step of forming a photoresist pattern on the at least one film. A method of manufacturing an array substrate for a liquid crystal display, the method comprising the steps of: a) forming a gate on a substrate; b) forming a gate insulating layer on a substrate including the gate; c) at the gate Forming a semiconductor layer on the insulating layer; d) forming a source and a drain on the semiconductor layer; e) forming a pixel electrode connected to the drain, Wherein at least one of the steps a), d) and e) comprises the steps of: forming a monolayer film selected from the group consisting of silver or a silver alloy, and a multilayer film composed of the monolayer film and the indium oxide film. At least one film; and the at least one film is etched using the etchant composition of any one of claims 1 to 4 to form respective electrodes. The method of claim 7, wherein the array substrate for the liquid crystal display is an array substrate for a thin film transistor.