KR20090112112A - Manufacturing method of array substrate for liquid crystal display - Google Patents

Abstract

PURPOSE: A method for manufacturing an array substrate for an LCD(Liquid Crystal Display) is provided to maximize the process efficiency by etching a molybdenum system metal/aluminum based metallurgy double film and an indium oxide film at the same time. CONSTITUTION: A method for manufacturing an array substrate for an LCD(Liquid Crystal Display) comprises the steps of: forming a gate electrode on a substrate; forming a gate insulating layer on the substrate including the gate electrode; forming a semiconductor layer on the gate insulating layer; and forming a pixel electrode connected to a drain electrode.

Description

MANUFACTURING METHOD OF ARRAY SUBSTRATE FOR LIQUID CRYSTAL DISPLAY}

The present invention provides a method for producing an array substrate for a liquid crystal display device, an etchant composition of a molybdenum-based metal / aluminum metal double film and an indium oxide film used in the method, and a molybdenum-based metal / aluminum metal double film using the etchant composition. Or it relates to an etching method of the indium oxide film.

During the manufacture of a semiconductor device for driving a liquid crystal display device, a process of forming a metal wiring on a substrate is usually performed by a metal film forming process by sputtering or the like, photoresist coating, exposure and development, and photoresist in a selective region. It consists of the formation process and the step by an etching process, and includes the washing process before and behind an individual unit process, etc. The etching process refers to a process of leaving a metal film in a selective region using a photoresist as a mask, and typically, dry etching using plasma or wet etching using an etching solution is used.

In the above semiconductor device, a metal commonly used as a wiring material for TFT-LCD (Thin Film Transistor-Liquid Crystal Display) is aluminum (Al) or an aluminum alloy, and pure aluminum has a weak resistance to chemicals and is used in a subsequent process. May be used in the form of aluminum alloy or may have another metal layer on the aluminum or aluminum alloy layer, such as molybdenum (Mo), chromium (Cr), tungsten (W), tin (Sn) A multilayer laminated structure is used.

By the way, in the case of the Mo / Al double layer, for example, when wet etching with a conventional aluminum etching solution mainly composed of phosphoric acid, the upper Mo layer is lower than the aluminum etching rate, so the upper Mo layer is the lower aluminum layer. It represents a poor profile that has a cross section protruding out of it. This poor profile results in poor step coverage in subsequent processes and increases the likelihood that the top layer is disconnected from the slope or the upper and lower metals are shorted.

Recently, in order to solve the above problems, Korean Patent No. 579511 consists of nitric acid (HNO ₃ ), iron nitrate (Fe (NO ₃ ) ₃ ), perchloric acid (HClO ₄ ), and ammonium fluoride (NH ₄ F). A method of collectively etching molybdenum / aluminum bilayer using an etchant has been presented.

However, when etching the molybdenum / aluminum double layer substrate with the etchant, fine etching residues remain on the substrate to generate a leakage current during TFT On / Off driving, resulting in signal delay. Picture distortion may occur. In addition, when the indium oxide film is etched with the etchant, there is a disadvantage that an indium oxide film residue remains.

In the technical field, an etching solution that does not generate fine etching residues is required to realize high image quality, and a molybdenum / aluminum double layer used as a gate wiring and an indium oxide film used as a pixel electrode may be collectively etched to simplify the process. There is a need for development of an etchant composition that can be used.

Accordingly, an object of the present invention is that there is no occurrence of fine etching residues during the etching of the molybdenum-based metal / aluminum-based metal double layer, there is no residue when etching the indium oxide film, the molybdenum-based metal / aluminum-based metal double layer and indium It is to provide an etching liquid composition capable of collectively etching an oxide film.

In addition, the present invention is to provide an etching method of the molybdenum-based metal / aluminum-based metal double film and the indium oxide film using the etchant composition.

In addition, the present invention provides a method for manufacturing an array substrate for a liquid crystal display device comprising the step of etching the molybdenum-based metal / aluminum-based metal double film and / or indium oxide film using the etching liquid composition.

In addition, the present invention provides an array substrate for a liquid crystal display device manufactured by the above manufacturing method.

In order to achieve the above object, the present invention,

A) iron nitrate (Fe (NO ₃ ) ₃ ) 2 to 5% by weight;

B) 0.1 to 1% by weight of fluorine-containing compound;

C) 8-15 wt% nitric acid (HNO ₃ );

D) 1 to 5 weight percent acetic acid (CH ₃ COOH);

E) copper chloride (CuCl ₂ ) 0.1 to 5% by weight; And

F) It provides an etching liquid composition of the molybdenum-based metal / aluminum-based metal double film and the indium oxide film containing a residual amount of water.

In addition, the present invention,

Forming a molybdenum-based metal / aluminum-based metal double layer on the substrate;

Selectively leaving a photoreactive material on the molybdenum-based metal / aluminum-based metal double layer; And

It provides an etching method of molybdenum-based metal / aluminum-based metal double layer comprising the step of etching the molybdenum-based metal / aluminum-based metal double layer or indium oxide film using the etchant composition of the present invention.

In addition, the present invention,

Forming an indium oxide film on the substrate;

Selectively leaving a photoreactive material on the indium oxide film; And

It provides an etching method of the indium oxide film comprising the step of etching the indium oxide film using the etchant composition of the present invention.

In addition, the present invention,

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 on the gate insulating layer;

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

e) forming a pixel electrode connected to the drain electrode

In the manufacturing method of the array substrate for a liquid crystal display device comprising:

In steps a) and d), a molybdenum-based metal / aluminum-based metal double layer is formed on the substrate and then etched with the etchant composition of the present invention to form a gate electrode, a source electrode, and a drain electrode. The present invention provides a method of manufacturing an array substrate for a liquid crystal display device, wherein after forming an indium oxide film, the pixel electrode is formed by etching the etching liquid composition of the present invention.

When etching the molybdenum-based metal / aluminum-based metal double film or indium oxide film using the etchant composition of the present invention, there is no occurrence of fine etching residue in the case of the aluminum-based metal / molybdenum-based metal double film. In addition, even after etching a large amount of substrate, the initial etching characteristics are maintained due to the minimized galvanic effect, and even after etching the indium oxide layer with the same etching solution, the etching residues exhibit excellent etching characteristics. Accordingly, the etchant composition of the present invention in the manufacture of an array substrate for a liquid crystal display device comprising a gate electrode, a source electrode and a drain electrode formed of a molybdenum-based metal / aluminum metal double film, and / or a pixel electrode formed of an indium oxide film. In the case of using, the driving characteristics of the liquid crystal display device can be improved. In addition, it is possible to batch-etch the molybdenum-based metal / aluminum-based metal double layer and indium oxide layer to maximize the process efficiency.

Hereinafter, the present invention will be described in detail.

I. Etchant  Composition

The present invention provides A) iron nitrate (Fe (NO ₃ ) ₃ ), B) fluorine-containing compound, C) nitric acid (HNO ₃ ), D) acetic acid (CH ₃ COOH), E) copper chloride (CuCl ₂ ), and F) An etching liquid composition of a molybdenum-based metal / aluminum-based metal double film and an indium oxide film containing water.

In the present invention, the molybdenum-based metal and the aluminum-based metal are concepts including alloys thereof, and the indium oxide film is a concept including an indium zinc oxide film (IZO) or an indium tin oxide film (ITO).

In the etching solution composition of the present invention, A) iron nitrate (Fe (NO ₃ ) ₃ ) is used as an oxidizing agent for etching molybdenum-based metal / aluminum-based metal double film and indium oxide film. The A) iron nitrate is preferably included in 2 to 5% by weight based on the total weight of the etchant composition of the present invention. When included in the above range, it is possible to implement a sufficient etching ability, it is possible to implement a uniform etching rate for the molybdenum-based metal and aluminum-based metal.

In the etching liquid composition of the present invention, the B) fluorine-containing compound speeds up the aluminum etching rate when etching the molybdenum-based metal / aluminum-based metal double layer, and when etching the indium oxide film, increases the etching rate of the indium oxide film. The B) fluorine-containing compound is preferably included in 0.1 to 1% by weight based on the total weight of the composition. When included in the above range, it is possible to implement a suitable etching rate for the molybdenum-based metal / aluminum-based metal double film and the indium oxide film. In addition, the molybdenum-based metal and the aluminum-based metal may be etched at a uniform etching rate. In addition, it is possible to prevent attack of the insulating film located under the indium oxide film. The B) fluorine-containing compound is preferably one or two or more selected from NH ₄ FHF, KFHF, NaFHF, KF, and NaF, and more preferably NH ₄ FHF, but is not limited thereto.

In the etchant composition of the present invention, C) nitric acid (HNO ₃ ) speeds up the etching rate thereof when the molybdenum metal / aluminum metal double layer is etched. The C) nitric acid is preferably included in 8 to 15% by weight relative to the total weight of the composition. When included in the above-described range, it is possible to implement a suitable etching rate for the molybdenum-based metal / aluminum-based metal double layer and to easily control the process time. In addition, after etching, no etching residue occurs.

In the etchant composition of the present invention, D) acetic acid (CH ₃ COOH) to lower the pH in etching the molybdenum-based metal / aluminum-based metal double layer to help the etching proceeds actively, by removing the etching residue generated during etching It serves to prevent the residue thereof. The D) acetic acid is preferably included in 1 to 5% by weight relative to the total weight of the composition. If included in the above range, it is possible to implement a suitable etching rate for the molybdenum-based metal / aluminum-based metal double layer. In addition, it is possible to prevent an attack on the insulating film located under the molybdenum metal / aluminum metal double film.

In the etchant composition of the present invention, E) copper chloride (CuCl ₂ ) prevents the molybdenum-based metal oxide film from resorbing onto the substrate. This is possible because the E) copper chloride has a mechanism for removing the molybdenum metal oxide film. The E) copper chloride is preferably contained in 0.1 to 5% by weight based on the total weight of the composition. When included in the above range, it is possible to prevent the molybdenum-based metal oxide film from being resorbed on the substrate. In addition, it is possible to prevent the occurrence of residues during the etching of the indium oxide film.

In the etchant composition according to the present invention, water is not particularly limited, but deionized water is preferred. More preferably, deionized water having a specific resistivity of 18 ㏁ / cm or more, which shows the degree of removal of ions in water, may be used.

A) iron nitrate, B) fluorine-containing compounds, C) nitric acid, D) acetic acid and E) copper chloride used in the present invention can be prepared by a conventionally known method, it is preferable to have a purity for semiconductor processing. .

In addition, the etchant composition according to the present invention may further include any additives commonly used in the art for improving etching performance, for example, a surfactant, a metal ion sequestrant or a corrosion inhibitor.

The surfactant serves to decrease the surface tension to increase the uniformity of the etching. Such surfactants are preferably surfactants that can withstand etching solutions and are compatible. Examples thereof include any anionic, cationic, zwitterionic or nonionic surfactant. In addition, a fluorine-based surfactant can be used as the surfactant. The additive is preferably included in 0.0001 to 0.01% by weight based on the total weight of the composition.

The etchant composition according to the present invention may collectively etch the molybdenum-based metal / aluminum-based metal double layer and an indium oxide layer, that is, an indium zinc oxide layer (IZO), an indium tin oxide layer (ITO), or the like.

The etching liquid composition according to the present invention does not generate fine etching residue with respect to the molybdenum-based metal / aluminum-based metal double layer, and thus has excellent etching characteristics. Has excellent properties to minimize.

II. Etching method

The present invention comprises the steps of forming a molybdenum-based metal / aluminum-based metal double film on the substrate; Selectively leaving a photoreactive material on the molybdenum-based metal / aluminum-based metal double layer; And it provides an etching method of molybdenum-based metal / aluminum-based metal double film comprising the step of etching the molybdenum-based metal / aluminum-based metal double film using the etchant composition of the present invention.

In addition, the present invention, forming an indium oxide film on a substrate; Selectively leaving a photoreactive material on the indium oxide film; And etching the indium oxide film using the etchant composition of the present invention.

The photoreactive material above is preferably a conventional photoresist material, which may optionally be left by conventional exposure and development processes.

III. Manufacturing Method of Array Substrate for Liquid Crystal Display

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 on the gate insulating layer; d) forming source and drain electrodes on the semiconductor layer; And e) forming a pixel electrode connected to the drain electrode.

In steps a) and d), a molybdenum-based metal / aluminum-based metal double layer is formed on the substrate and then etched with the etchant composition of the present invention to form a gate electrode, a source electrode, and a drain electrode. After the indium oxide film is formed, the method of manufacturing an array substrate for a liquid crystal display device characterized in that the pixel electrode is formed by etching with the etchant composition of the present invention.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, the step a) comprises: a1) depositing a molybdenum-based metal / aluminum-based metal double layer on the substrate by using a vapor deposition method or a sputtering method; And a2) etching and patterning the molybdenum-based metal / aluminum-based metal double layer with the etchant of the present invention to form a gate wiring. Here, the method of forming the molybdenum-based metal / aluminum-based metal double film on the substrate is not limited to the above-described ones.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in step b), silicon nitride (SiN _X ) is deposited on the gate electrode formed on the substrate to form a gate insulating layer. Here, the material used for forming the gate insulating layer is not limited to silicon nitride (SiN _x ), and the gate insulating layer may be formed using a material selected from various inorganic insulating materials including silicon oxide (SiO ₂ ). have.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in step c), a semiconductor layer is formed on the gate insulating layer by chemical vapor deposition (CVD). In other words, the active layer and the ohmic contact layer are sequentially formed and then patterned by dry etching. The active layer is generally formed of pure amorphous silicon (a-Si: H), and the ohmic contact layer is formed of amorphous silicon (n ⁺ a-Si: H) containing impurities. Chemical vapor deposition (CVD) may be used to form the active layer and the ohmic contact layer, but is not limited thereto.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, step d) comprises: d1) forming source and drain electrodes on the semiconductor layer; And d2) forming an insulating layer on the source and drain electrodes. In the step d1), a metal film is deposited on the ohmic contact layer by sputtering and etched with an etchant of the present invention to form a source electrode and a drain electrode. Here, the method of forming the metal film on the substrate is not limited to the above examples. In step d2), an inorganic insulating group including silicon nitride (SiN _x ) and silicon oxide (SiO ₂ ) or a benzocyclobutene (BCB) and an acrylic resin (resin) are formed on the source electrode and the drain electrode. The insulating layer may be formed of a single layer or a double layer by selecting from a group of organic insulating materials. The material of the insulating layer is not limited to only those exemplified above. In particular, when the source and drain electrodes are made of the same material as the gate electrode, the etchant composition may also be applied to the process of forming the source and drain electrodes.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in step e), a pixel electrode connected to the drain electrode is formed. For example, a transparent conductive material such as an indium tin oxide (ITO) or an indium zinc oxide (IZO) is deposited through a sputtering method, and the pixel electrode is formed by etching the etchant composition according to the present invention. The method of depositing the indium oxide film is not limited only to the sputtering method.

In addition, in the method of manufacturing an array substrate for a liquid crystal display device, an attack on a data line including a drain electrode positioned under the pixel electrode may be minimized during the e) step etching process using the etchant composition according to the present invention. As a result, an excellent array substrate for a liquid crystal display device capable of improving driving characteristics of a TFT-LCD can be manufactured, and productivity of the array substrate for a liquid crystal display device can be improved.

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

Example  1 to 10 and Comparative example  1, 2: Etchant  Preparation of the composition

Semiconductor process grades Fe (NO ₃ ) ₃ , NH ₄ FHF, HNO ₃ , CH ₃ COOH, CuCl ₂ And oxalic acid were mixed as shown in Table 1 below, and deionized water was added so that the total weight of the composition was 100% by weight to prepare an etching solution.

Etch solution composition (% by weight) Fe (NO ₃ ) ₃ NH ₄ FHF HNO ₃ CH ₃ COOH CuCl ₂ Oxalic acid Deionized water Example 1 2.0 0.3 8 1.0 0.1 - Remaining amount Example 2 2.5 0.3 9 2.0 0.2 - Remaining amount Example 3 3.0 0.4 10 2.0 0.5 - Remaining amount Example 4 3.5 0.4 11 2.0 1.0 - Remaining amount Example 5 3.5 0.3 8 5.0 0.2 - Remaining amount Example 6 3.5 0.5 12 2.0 0.3 - Remaining amount Example 7 4.0 0.8 12 3.0 1.0 - Remaining amount Example 8 4.0 1.0 14 4.5 0.7 - Remaining amount Example 9 4.5 0.8 12 4.0 2.0 - Remaining amount Example 10 5.0 0.9 15 5.0 4.0 - Remaining amount Comparative Example 1 3.0 0.4 10 3 - - Remaining amount Comparative Example 2 - - - - - 5.0 Remaining amount

Test Example  1: Molybdenum Metal / Aluminum Metal Double membrane  And Indium oxide film Etching  Property evaluation

The molybdenum / aluminum double film was sequentially deposited on the glass substrate by the sputtering method, and the indium oxide film was also deposited in the same manner as above. After coating a photoresist of about 1㎛ on it, and optionally formed a pattern to prepare a test piece. The test pieces were etched using the spray method with the etching solutions of Examples 1 to 10, and Comparative Examples 1 and 2. Each of the test pieces etched in Examples 1 to 10, Comparative Example 1 and Comparative Example 2 was examined using an electron scanning microscope (SEM; Hitach, S-4700), the results are shown in Table 2 and Figure 1 to 4 are shown.

Criteria for evaluating the etching characteristics of the molybdenum-based metal / aluminum-based metal double layer and indium oxide layer are as follows.

-Etching Characteristics of Molybdenum Metal / Aluminum Metal Double Layer

(Circle): No fine residue generate | occur | produces, x: There exists fine residue.

-Etching Characteristics of Indium Oxide

(Circle): No residue generate | occur | produced, X: There exists a residue occurrence.

Etching characteristics Molybdenum Metal / Aluminum Metal Double Layer Indium oxide film Example 1 ○ ○ Example 2 ○ ○ Example 3 ○ ○ Example 4 ○ ○ Example 5 ○ ○ Example 6 ○ ○ Example 7 ○ ○ Example 8 ○ ○ Example 9 ○ ○ Example 10 ○ ○ Comparative Example 1 × × Comparative Example 2 × ×

As shown in Table 2, the copper chloride does not contain In the etchant composition of Comparative Example 1, a fine molybdenum oxide film residue was generated when the molybdenum / aluminum double layer was etched (see FIG. 3), and the etchant composition of Comparative Example 2 containing oxalic acid and deionized water generated an indium oxide film residue ( See FIG. 4).

However, no residue (fine residue) was generated when the molybdenum / aluminum double film and the indium oxide film were etched with the etching solution compositions (Examples 1 to 10) according to the present invention. This fact can also be confirmed in FIG. 1 (SEM photograph of the surface of the molybdenum / aluminum double membrane etched by the etchant composition of Example 1) and FIG. 2 (SEM photograph of the indium oxide film etched by the etchant composition of Example 1).

Therefore, it can be seen that the etching solution of the present invention exhibits excellent etching characteristics with respect to the molybdenum metal / aluminum metal and the indium oxide film.

1 is a scanning electron micrograph of the entire surface after etching the molybdenum / aluminum double layer using the etchant composition according to Example 1 of the present invention.

Figure 2 is an electron scanning microscope photograph of the entire surface after etching the indium oxide film using an etchant composition according to Example 1 of the present invention.

Figure 3 is a scanning electron micrograph of the entire surface after etching the molybdenum / aluminum metal double layer using the etchant composition according to Comparative Example 1 of the present invention.

4 is an electron scanning microscope photograph of the entire surface of the indium oxide film after etching using the etchant composition according to Comparative Example 2 of the present invention.

Claims (10)

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 on the gate insulating layer; d) forming source and drain electrodes on the semiconductor layer; And e) forming a pixel electrode connected to the drain electrode In the manufacturing method of the array substrate for a liquid crystal display device comprising: In steps a) and d), a molybdenum-based metal / aluminum-based metal double layer is formed on the substrate, and then etched with an etchant composition to form a gate electrode, a source electrode, and a drain electrode. In step e), an indium oxide film is formed. After forming, by etching with the etchant composition to form a pixel electrode, The etchant composition, Regarding the total weight of the composition, A) iron nitrate (Fe (NO ₃ ) ₃ ) 2 to 5% by weight; B) 0.1 to 1% by weight of fluorine-containing compound; C) 8-15 wt% nitric acid (HNO ₃ ); D) 1 to 5 weight percent acetic acid (CH ₃ COOH); E) copper chloride (CuCl ₂ ) 0.1 to 5% by weight; And F) A method of manufacturing an array substrate for a liquid crystal display device, comprising a residual amount of water. The method of claim 1, wherein the fluorine-containing compound is at least one selected from NH ₄ FHF, KFHF, NaFHF, KF, and NaF. The method of claim 1, wherein the indium oxide film is an indium zinc oxide film (IZO) or an indium tin oxide film (ITO). An array substrate for a liquid crystal display device manufactured by the method of claim 1. A) iron nitrate (Fe (NO ₃ ) ₃ ) 2 to 5% by weight; B) 0.1 to 1% by weight of fluorine-containing compound; C) 8-15 wt% nitric acid (HNO ₃ ); D) 2 to 5 weight percent acetic acid (CH ₃ COOH); E) copper chloride (CuCl ₂ ) 0.1 to 5% by weight; And F) An etchant composition of a molybdenum-based metal / aluminum-based metal double film and an indium oxide film containing a residual amount of water. The etching liquid composition of claim 5, wherein the fluorine-containing compound is one or two or more selected from NH ₄ FHF, KFHF, NaFHF, KF, and NaF. . The method of claim 5, wherein the etchant composition of the molybdenum-based metal / aluminum-based metal double layer and indium oxide film further comprises one or two or more additives selected from surfactants, metal ion blocking agents or corrosion inhibitors. Etch solution composition. The etchant composition of claim 5, wherein the indium oxide film is an indium zinc oxide film (IZO) or an indium tin oxide film (ITO). 7. Forming a molybdenum-based metal / aluminum-based metal double layer on the substrate; Selectively leaving a photoreactive material on the molybdenum-based metal / aluminum-based metal double layer; And The etching method of the molybdenum-based metal / aluminum-based metal double layer comprising the step of etching the molybdenum-based metal / aluminum-based metal double layer using the etching liquid composition of any one of claims 5 to 8. Forming an indium oxide film on the substrate; Selectively leaving a photoreactive material on the indium oxide film; And The etching method of the indium oxide film comprising etching the indium oxide film using the etching solution composition of any one of claims 5 to 8.

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