KR20090081938A - Etchant composition for Ag thin layer and method for fabricating metal pattern using the same - Google Patents

Abstract

An etchant composition for a silver-based thin film, and a method for forming a metal pattern using the composition are provided to prevent the damage of underlayer and the generation of residue and to reduce the side etching. An etchant composition for a silver or silver alloy single layer or a multilayer comprising the single layer and an indium oxide film comprises a Fe^3+ salt compound 1 ~ 15 weight%; nitric acid 1 ~ 10 weight%; acetic acid 1 ~ 30 weight%; sodium phosphate monobasic 0.1 ~ 5 weight%; a corrosion inhibitor 0.01 ~ 3 weight%; and water 37 ~ 96.89 weight%.

Description

Etchant composition for Ag thin layer and method for fabricating metal pattern using the same}

The present invention relates to an etching liquid composition of a single film made of silver (Ag) or silver alloy, and a multi-film consisting of the single film and an indium oxide film, a method of forming a metal pattern using the same, and an array substrate for a liquid crystal display device using the same. It relates to a manufacturing method.

Liquid crystal display is one of the most widely used flat panel displays. It consists of two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween. The display device is applied to rearrange the liquid crystal molecules of the liquid crystal layer to control the amount of light transmitted.

Among the liquid crystal display devices, the one currently used is a form in which the field generating electrodes are provided on two substrates, respectively. Among them, a plurality of pixel electrodes are arranged in a matrix on one substrate, and one common electrode covers the entire surface of the substrate on another substrate. In such a liquid crystal display, an image is displayed by applying a separate voltage to each pixel electrode. To this end, a thin film transistor, which is a three-terminal element for switching a voltage applied to a pixel electrode, is connected to each pixel electrode, and a gate line for transmitting a signal for controlling the thin film transistor and a voltage to be applied to the pixel electrode. A data line to transfer is formed on the substrate.

On the other hand, as the display area of the liquid crystal display device becomes larger and larger, the gate line and the data line connected to the thin film transistor also become longer, thereby increasing the resistance of the wiring. For this reason, it is not possible to continue to use chromium (Cr), molybdenum (Mo), aluminum (Al), and alloys thereof that have been used in the past as gates and data wirings used in thin film transistors (TFTs). This makes it difficult to make the flat panel display large and high resolution. Therefore, in order to solve such problems as signal delay caused by an increase in resistance, it is necessary to form the gate line and the data line with a material having the lowest specific resistance.

Conductive metals such as Indium Tin Oxide (ITO) and Indium Zinc Oxide (IZO) have relatively high transmittance to light and are conductive, so they are widely used as color filter electrodes for flat panel displays. It is used. However, these metals also have high resistance, which hinders the enlargement of the flat panel display device and the high resolution. In addition, in the past, Al reflector has been mainly used in products, but in order to realize low power consumption through improved brightness, the state is seeking to change materials to metal with higher reflectance.

To this end, a silver (Ag: 1.59 µΩcm) film, silver alloy film, or a multi-layer film including silver film or silver alloy film, which has a lower specific resistance and higher brightness than metals applied to a flat panel display device, is used as a color filter electrode, LCD Efforts have been made to increase the size of flat panel display devices, high resolution, and low power consumption by applying them to wirings and reflecting plates, and as part of such efforts, etching solutions for applying to such materials have been developed.

However, silver (Ag) is extremely poor in adhesion to an insulating substrate such as glass or a lower substrate such as a semiconductor substrate made of intrinsic amorphous silicon, doped amorphous silicon, or the like, so that deposition is not easy and the wiring is lifted. Lifting or feeling is easily caused. In addition, even when a silver (Ag) conductive layer is deposited on a substrate, when a conventional etching solution is used to pattern the silver (Ag) conductive layer, silver (Ag) may be excessively etched or etched unevenly, thereby causing a phenomenon of lifting or peeling of the wiring. The side profile of is bad.

In the case of Korea Patent Registration 10-0579421, an auxiliary oxide dissolving agent and a fluorine-containing carbon-based surfactant were used for phosphoric acid, nitric acid, and acetic acid, but the SO ₄ ^{2 -} compound used as the auxiliary oxide dissolving agent reacted with silver (Ag) to react with AgS. It remains as a residue in the substrate in the form, and ClO ₄ ^- compound is difficult to use as an environmental regulatory substance. In addition, in the case of the fluorine-containing carbon-based surfactant, when the lower layer of silver is an organic insulating layer, the organic insulating layer on the edge of the substrate is easily damaged by such a component, causing a problem of peeling.

The present invention is to solve the problems of the prior art as described above, the amount of side etching in the etching of a single film made of silver (Ag) or silver alloy and the multiple film composed of the single film and the indium oxide film, the lower An object of the present invention is to provide an etching liquid composition which exhibits uniform etching characteristics without damage to a film and generation of residues, a method of forming a metal pattern using the same, and a method of manufacturing an array substrate for a liquid crystal display device using the same.

The present invention is 1 to 15% by weight Fe ^{3 +} salt compound, 1 to 10% by weight nitric acid, 1 to 30% by weight acetic acid, 0.1 to 5% by weight sodium monophosphate, 0.01 to 3% by weight corrosion inhibitor And it provides a single film of a silver or silver alloy containing 37 to 96.89% by weight of water and a multi-film etching liquid composition composed of the single film and the indium oxide film.

In addition, the present invention

Forming one or more selected from a single film of silver (Ag) or silver alloy and multiple films including the single film and the indium oxide film on the substrate; And

It provides a method of forming a metal pattern comprising the step of etching one or a plurality of the film formed in the etching liquid 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;

Any one or more of steps a), d) and e) forms a silver or silver alloy single film and any one or more selected from multiple films composed of the single film and the indium oxide film, and It provides a method of manufacturing an array substrate for a liquid crystal display device comprising the step of etching each of the etching liquid composition of the present invention to form each electrode.

As described above, the etching liquid composition of the present invention has a small amount of side etching in etching a single film of silver or a silver alloy and multiple films composed of the single film and the indium oxide film, and is uniform without damage to the underlying film and occurrence of residue. Etching characteristics can play an important role in achieving high resolution, large size, and low power consumption of the flat panel display.

The present invention is 1 to 15% by weight Fe ^{3 +} salt compound, 1 to 10% by weight nitric acid, 1 to 30% by weight acetic acid, 0.1 to 5% by weight sodium monophosphate, 0.01 to 3% by weight corrosion inhibitor And an etching solution composition of a single film of silver or silver alloy containing 37 to 96.89% by weight of water and a multi-layer consisting of the single film and the indium oxide film.

The etchant composition of the present invention is characterized by being capable of simultaneously etching a single film of silver (Ag) or a silver alloy and multiple films composed of the single film and the indium oxide film.

In the present invention, the multilayer film composed of a single film of silver (Ag) or silver alloy and an indium oxide film means, for example, a double film of indium oxide film / silver film or a triple film of indium oxide film / silver film / indium oxide film, and the like. Indium means indium tin oxide (ITO), indium zinc oxide (IZO), or the like.

Fe ^{3 +} salt compound contained in the etching liquid composition of the present invention as a component is used as the primary oxidizing agent, acts to wet etching by oxidation of (Ag) and indium oxide. The content of the Fe ³⁺ salt compound is 1 to 15% by weight based on the total weight of the etchant composition. When the Fe ³⁺ salt compound is included in less than 1% by weight may cause a decrease in the etching rate of the silver film and a poor etching profile, when the Fe ³⁺ salt compound exceeds 15% by weight due to overetching of the indium oxide film, for example, In the case of etching the triple layer of the indium oxide film / silver film / indium oxide film, a surface layer of silver may be lifted, and a problem may occur in that the silver falls off the surface of the substrate and is resorbed by heat treatment during the subsequent process.

The Fe ^{3 +} salt compound is provided in the form of a salt containing Fe ^{3 +} , the type is not particularly limited, but specific examples are FeCl ₃ , Fe (NO ₃ ) ₃ , Fe ₂ (SO ₄ ) ₃ , NH ₄ Fe (SO _{4) 2,} and the like Fe (ClO _{4) 3,} FePO _4, and, these may be used alone or as a mixture of two or more kinds.

Nitric acid (HNO ₃ ) included in the etchant composition of the present invention serves as a component used as an auxiliary oxidant to wet-etch silver and indium oxide. The content of nitric acid (HNO ₃ ) is 1 to 10% by weight based on the total weight of the composition. If the content of nitric acid is less than 1% by weight, the etching rate of the silver (Ag) film and the indium oxide film decreases, thereby causing unevenness in the substrate, resulting in staining, and in case of exceeding 10% by weight, For example, when the triple layer of the indium oxide film / silver film / indium oxide film is etched, the etching rate of the indium oxide film is accelerated on the upper and lower portions, and there is a disadvantage that a problem occurs in the subsequent process due to the undercut of the upper and lower indium oxide films.

Acetic acid (CH ₃ COOH) included in the etchant composition of the present invention is a component used as an auxiliary oxidant, and serves to wet etch by oxidizing silver (Ag). The amount of acetic acid is 1 to 30% by weight based on the total weight of the etchant composition. If the content of acetic acid is less than 1% by weight, there is a problem of unevenness in the etching rate in the substrate, and if it exceeds 30% by weight, foaming occurs. If such foam is present in the substrate, complete etching does not occur. This can cause problems in subsequent processes.

Sodium monophosphate included in the etchant composition of the present invention as a component used as an additive, serves to uniformly control and etch the CD skew (CD Skew) for the thin film during wet etching. The content of the first sodium phosphate is 0.1 to 5% by weight based on the total weight of the composition. When the content of sodium monophosphate is less than 0.1% by weight, etching uniformity (uniformity) in the substrate is lowered, and when it is more than 5% by weight, the etching rate is lowered to achieve a desired etching rate, and silver etching remains. Water can be generated, which can be a problem in the process.

Corrosion inhibitor included in the etchant composition of the present invention as a component used for controlling the etching amount of silver and the control of the etching rate, may be used alone or two or more selected from amines, azoles and the like, the amines and azoles Specific examples of the class include m-toluylenediamine, ethylenediaminetetraacetate (EDTA), hexamethylenetetraamine (HMTA), triethylenetetraamine (TETA), octylamine, tetramethylenetetraamine (TMAH), benzotriazole ( BTA), 5-aminotetrazole (5-ATZ), triazole, and the like. The content of the corrosion inhibitor is 0.01 to 3% by weight based on the total weight of the etching liquid composition. When the content of the corrosion inhibitor is less than 0.01% by weight it may not function to suppress the etching of the silver during etching, if it exceeds 3% by weight rather the etching speed of the silver may be significantly lowered may cause an etching residue. .

Although the water contained in the etching liquid composition of this invention is not specifically limited, Deionized water is preferable. In particular, it is more preferable to use deionized water having a specific resistance value of the water (that is, the degree of removal of ions in the water) of 18 kV / cm or more. The water content is included in the range of 37 to 96.89% by weight based on the total weight of the composition, the content of which is included in the other components added in the form of an aqueous solution and the total amount of water alone.

The etchant composition of the present invention may further include a conventional additive in addition to the above-described components, and the additive may be a surfactant, a metal ion sequestrant, a corrosion inhibitor and a pH adjusting agent.

In the etchant composition of the present invention, the Fe ^{3 +} salt compound, nitric acid, acetic acid, monobasic sodium phosphate, corrosion inhibitors can be prepared according to a conventionally known method, and it is particularly preferable to have a purity for semiconductor processing.

The present invention also,

(i) forming a single film of silver (Ag) or silver alloy on the substrate and any one or more selected from a plurality of films including the single film and the indium oxide film; And

(ii) it provides a method of forming a metal pattern comprising the step of etching one or a plurality of the film formed in the etching liquid composition of the present invention.

In the method of forming the metal pattern, the step (i) includes the steps of providing a substrate and a multi-layer composed of a single film of silver (Ag) or a silver alloy on the substrate and the single film and an indium oxide film. Forming any one or multiple selected. The substrate may be cleaned in a conventional manner, and a wafer, a glass substrate, a stainless steel substrate, a plastic substrate, or a quartz substrate may be used. As a method of forming a single film of silver (Ag) or a silver alloy and a multilayer film composed of the single film and the indium oxide film on the substrate, various methods known to those skilled in the art can be used, and by using a vacuum deposition method or a sputtering method. It is preferable to form.

In the step (ii), the photoresist is formed on one or a plurality of films formed in the step (i), the photoresist is selectively exposed using a mask, the exposed photoresist is bent, and the The bent photoresist is developed to form a photoresist pattern. The one or more films on which the photoresist pattern is formed are etched using the etching solution composition of the present invention to complete a metal pattern.

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;

Any one or more of steps a), d) and e) forms a silver or silver alloy single film and any one or more selected from multiple films composed of the single film and the indium oxide film, and It provides a method of manufacturing an array substrate for a liquid crystal display device comprising the step of etching each of the etching liquid composition of the present invention to form each electrode.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, the step a) may include a1) a silver or silver alloy single film and the single film and indium oxide on the substrate by vapor deposition or sputtering. Depositing any one or more selected from among multiple films composed of films; And a2) patterning the one or more films formed above with the etchant of the present invention to form a gate electrode. Here, the method of forming one or a plurality of films on the substrate is not limited to those illustrated above.

In the method of manufacturing an array substrate for a liquid crystal display device according to the present invention, in the 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 the 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. Here, 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.

A method of manufacturing an array substrate for a liquid crystal display device according to the present invention, wherein 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 step d1), one or a plurality of silver or silver alloy single layers and multiple layers including the single layer and the indium oxide layer are deposited on the ohmic contact layer by sputtering, and the source is formed by etching with the etchant of the present invention. An electrode and a drain electrode are formed. Here, the method of forming the one or a plurality of films on the substrate is not limited to those illustrated above. 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 are included 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 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, by sputtering, any one or more selected from a single layer of silver or silver alloy and multiple layers including the single layer and the indium oxide layer are deposited, and the pixel electrode is formed by etching with the etchant composition of the present invention. . The method of depositing the indium oxide film is not limited only to the sputtering method.

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

Example  1-5: Etchant  Preparation of the composition and Etching  Property evaluation

A specimen was prepared by forming an a-ITO / Ag / a-ITO triple layer on the substrate and cutting it into 10 × 10 mm using a diamond knife. The etching solution was prepared to have an etching solution of 10 kg in Table 1. Etching solution prepared in the spray etching experiment equipment (manufactured by SEMES Co., Ltd.) was added to warm the temperature was set to 40 ℃, the etching process was performed when the temperature reached 40 ± 0.1 ℃. The total etching time was performed by giving 50% of the over etch based on End Point Detection (EPD).

After the substrates were etched, the substrates were removed, washed with deionized water, dried using a hot air dryer, and removed using a photoresist stripper. After washing and drying, the electron scanning microscope (SEM; manufactured by HITACHI Co., Ltd., model S-4700) was used to evaluate the etching characteristics of the side etching, the damage of the lower layer, and the extent of etching residue. Etch characteristics test results are shown in Table 1 below.

Example Composition (wt%) NH ₄ Fe (SO ₄ ) ₂ / nitric acid / acetic acid / NaH ₂ PO ₄ / ATZ / water Etch Characteristics Results Side Etch (μm) Lower membrane damage Silver residue One 3/4/15 / 0.5 / 0.05 / 77.45 0.10 radish radish 2 4/6/10 / 0.5 / 0.02 / 79.48 0.20 radish radish 3 5/8/20 / 2.0 / 0.1 / 64.9 0.25 radish radish 4 6/3/15/1 / 0.07 / 74.93 0.20 radish radish 5 7/6/20/2 / 0.5 / 64.5 0.30 radish radish

* ATZ: 5-aminotetrazole

As can be seen from Table 1, when the a-ITO / Ag / a-ITO substrate was etched using the etchant compositions of Examples 1 to 5 according to the present invention, side etch, underlayer damage and silver residue generation were observed. It shows good etching characteristics in all respects.

The SEM photograph after etching the a-ITO / Ag / ITO triple layer using the etchant composition of Example 3 was attached to FIG. 1A. In addition, the a-ITO / Ag / ITO triple layer was etched using the etchant composition of Example 3, and a SEM photograph of the substrate surface after stripping the photoresist was attached to FIG. 1B.

Comparative example  1 to 3: Etchant  Preparation of the composition and Etching  Property evaluation

A-ITO / Ag / a-ITO triple film was formed on the substrate, and a specimen was prepared by cutting 10 × 10 mm using a diamond knife. The etching solution was prepared to have an etching solution of 10 kg in Table 2. Etching solution prepared in the spray etching experiment equipment (manufactured by SEMES Co., Ltd.) was added to warm the temperature was set to 40 ℃, the etching process was performed when the temperature reached 40 ± 0.1 ℃. The total etching time was performed by giving 50% of the over etch based on End Point Detection (EPD).

After the substrates were etched, the substrates were removed, washed with deionized water, dried using a hot air dryer, and removed using a photoresist stripper. After washing and drying, the electron scanning microscope (SEM; manufactured by HITACHI Co., Ltd., model S-4700) was used to evaluate the etching characteristics of the side etching, the damage of the lower layer, and the extent of etching residue. Etch characteristics test results are shown in Table 2 below.

Comparative example Composition (wt%) NH4Fe (SO4) 2 / Nitric Acid / Acetic Acid / NaH ₂ PO ₄ / ATZ / Water Etch Characteristics Results Side Etch (μm) Lower membrane damage Silver residue One 6/4/15/1/5/69 Unetch radish U 2 8/2/20/7 / 0.02 / 62.98 Unetch radish U 3 4 / 0.1 / 25/2 / 0.05 / 68.85 Unetch radish U

As can be seen in Table 2, in the case of Comparative Example 1 in which the content of the corrosion inhibitor exceeds the range of the present invention, silver residues occurred, and Comparative Example 2 in which the content of the first sodium phosphate exceeded the range of the present invention. In the case of the etching rate was lowered to generate a silver residue, in the case of Comparative Example 3 in which the amount of nitric acid is contained in less than the range of the present invention, silver residue was generated.

The SEM photograph after etching the a-ITO / Ag / ITO triple layer using the etchant composition of Comparative Example 1 was attached to FIG. 2A. In addition, the a-ITO / Ag / ITO triple layer was etched using the etchant composition of Comparative Example 1, and a SEM photograph of the substrate surface after stripping the photoresist was attached to FIG. 2B.

1A is a SEM photograph after etching a-ITO / Ag / ITO triple layer using the etchant composition of Example 3,

FIG. 1B is a SEM photograph of the surface of the substrate after etching the a-ITO / Ag / ITO triple layer using the etchant composition of Example 3 and stripping the photoresist.

2A is a SEM photograph after etching a-ITO / Ag / ITO triple layer using the etchant composition of Comparative Example 1,

FIG. 2B is a SEM photograph of the surface of the substrate after etching the a-ITO / Ag / ITO triple layer using the etchant composition of Comparative Example 1 and stripping the photoresist.

Claims (9)

With respect to the composition total weight, Fe ^{3 +} salt of Compound 1 to 15% by weight, 1 to 10% by weight of nitric acid, 1 to 30% by weight of acetic acid, the first 0.1 to 5% by weight of sodium phosphate, 0.01 to 3% by weight of corrosion inhibitor, and water Etching liquid composition of a single film of silver or silver alloy containing 37 to 96.89% by weight and a multilayer consisting of the single film and the indium oxide film. The method according to claim 1, wherein the Fe ^{3 +} salt The compound is at least one member selected from the group consisting of FeCl ₃ , Fe (NO ₃ ) ₃ , Fe ₂ (SO ₄ ) ₃ , NH ₄ Fe (SO ₄ ) ₂ , Fe (ClO ₄ ) ₃ , and FePO ₄ The etching liquid composition of the single film | membrane of silver or silver alloy which consists of these, and the multilayer film | membrane which consists of the said single film and an indium oxide film. The etching liquid composition according to claim 1, wherein the corrosion inhibitor is at least one member selected from the group consisting of amines and azoles, and a multilayer composed of the single layer and the indium oxide layer. The method according to claim 3, wherein the amines and azoles are m-toluylenediamine, ethylenediaminetetraacetate (EDTA), hexamethylenetetraamine (HMTA), triethylenetetraamine (TETA), octylamine, tetramethylenetetraamine ( TMAH), benzotriazole (BTA), 5-aminotetrazole (5-ATZ), and triazole, wherein the etching solution composition of a single film of silver or silver alloy and a multilayer comprising the single film and the indium oxide film. The silver (Ag) or silver alloy of claim 1, wherein the etchant composition further comprises at least one additive selected from the group consisting of an etch regulator, a surfactant, a metal ion sequestrant, and a pH regulator. A film and an etching liquid composition of a multilayer comprising the single film and the indium oxide film. Forming one or more selected from a single film of silver (Ag) or silver alloy and multiple films including the single film and the indium oxide film on the substrate; And A method of forming a metal pattern comprising etching the one or a plurality of films formed in the etching liquid composition of any one of claims 1 to 5. The method of claim 6, further comprising forming a photoresist pattern on the formed one or a plurality of films. 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; Any one or more of steps a), d) and e) forms a silver or silver alloy single film and any one or a plurality selected from a single film and a multilayer film composed of the single film and the indium oxide film, and A method of manufacturing an array substrate for a liquid crystal display device, the method comprising etching the same with the etchant composition according to any one of claims 1 to 5 to form respective electrodes. The method of manufacturing an array substrate for a liquid crystal display device according to claim 8, wherein the array substrate for liquid crystal display device is a thin film transistor (TFT) array substrate.

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