KR101406362B1 - Etchant composition for Ag thin layer and method for fabricating metal pattern using the same - Google Patents

Abstract

The present invention relates to a process for the preparation of a composition comprising, by weight based on the total weight of the composition, from 1 to 15% by weight of an Fe ^{3 +} salt compound, from 1 to 10% by weight of nitric acid, from 1 to 30% by weight of acetic acid, from 0.1 to 5% And a method for forming an array substrate for a liquid crystal display device using the etchant composition, a method for forming a metal pattern using the same, and a method for manufacturing an array substrate using the same. .

Fe3 + salt, sodium phosphate monobasic, silver, indium oxide film, etchant, corrosion inhibitor

Description

[0001] The present invention relates to an etchant composition for a silver thin film and a method for forming a metal pattern using the same,

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

2. Description of the Related Art A liquid crystal display (LCD) is one of the most widely used flat panel displays, and is composed of two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween. And rearranges the liquid crystal molecules in the liquid crystal layer to adjust the amount of light transmitted.

Of the liquid crystal display devices, currently used are those in which electric 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 substrate on the other substrate. In such a liquid crystal display device, display of an image is performed by applying a separate voltage to each pixel electrode. To this end, a thin film transistor, which is a three terminal device for switching the voltage applied to the pixel electrode, is connected to each pixel electrode, 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 be transferred 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 lines and data lines connected to the thin film transistors become longer, and accordingly the resistance of the wirings also increases. For this reason, the continuous use of chromium (Cr), molybdenum (Mo), aluminum (Al), and alloys thereof, which have been conventionally used, as gates and data wirings used in thin film transistors Which makes it difficult to make the flat panel display large-sized and high-resolution realization. Therefore, in order to solve such a problem of signal delay due to such an increase in resistance, it is necessary to form the gate line and the data line with a material having the lowest possible resistivity.

BACKGROUND ART Conductive metals such as indium tin oxide (ITO) and indium zinc oxide (IZO) have excellent transmittance to light and have conductivity. Therefore, they are widely used as electrodes of color filters used in flat panel display devices Is used. However, these metals also have a high resistance, which is an obstacle to the enlargement of the flat panel display device and the realization of high resolution through improvement of the response speed. In the case of reflectors, past Al reflectors have mainly been used in products. However, in order to realize low power consumption by improving luminance, materials are being sought for metal with higher reflectance.

For this purpose, a silver (Ag: specific resistance: about 1.59 μΩcm) film having a low resistivity and a high luminance as compared with metals applied to a flat panel display, a silver film, a silver film or a silver film, Efforts have been made to increase the size of flat panel display devices and realize high resolution and low power consumption by applying them to wirings and reflectors. As part of such efforts, etching solutions for these materials are being 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 or doped amorphous silicon or the like, lifting or feeling is easily induced. Further, even when a silver (Ag) conductive layer is deposited on a substrate, Ag is excessively etched or non-uniformly etched when a conventional etching solution is used for patterning the same, The side profile of the substrate is poor.

In Korean Patent No. 10-0579421, a small carbon surfactant was used in combination with an auxiliary oxide dissolving agent in phosphoric acid, nitric acid, and acetic acid. However, the SO ₄ ^{2 -} compound used as a secondary oxide dissolving agent reacted with silver (Ag) And ClO ₄ ^- compounds are difficult to use as environmentally regulated substances. Also, in the case of the Hambil small carbon surfactant, the organic insulating film at the edge of the substrate is easily damaged due to such components, and peeling phenomenon (peeling) occurs when the lower film of silver is an organic insulating film.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the conventional art as described above, and it is an object of the present invention to provide a method of etching a single film made of silver (Ag) or a silver alloy and an indium oxide film, A method of forming a metal pattern using the etchant composition, and a method of manufacturing an array substrate for a liquid crystal display device using the etchant composition, which exhibit uniform etching characteristics without damaging the bottom film and forming residues.

The present invention relates to a process for the preparation of a composition comprising, by weight based on the total weight of the composition, from 1 to 15% by weight of an Fe ^{3 +} salt compound, from 1 to 10% by weight of nitric acid, from 1 to 30% by weight of acetic acid, from 0.1 to 5% A single layer of silver or silver alloy, and an indium oxide layer.

In addition,

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

And etching the one or a plurality of the formed films with the etching solution composition of the present invention.

In addition,

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, the method comprising the steps of:

Wherein at least one of the steps a), d), and e) is formed of a silver or silver alloy monolayer and a multilayer composed of the single film and the indium oxide film; And etching each of the electrodes with the etchant composition of the present invention to form respective electrodes. The present invention also provides a method of manufacturing an array substrate for a liquid crystal display device.

As described above, the etchant composition of the present invention has a small amount of side etching when etching a single film of silver or silver alloy and a multi-layer film composed of the single film and the indium oxide film, And thus can play an important role in achieving high resolution, large size, and low power consumption of the flat panel display device.

The present invention relates to a process for the preparation of a composition comprising, by weight based on the total weight of the composition, from 1 to 15% by weight of an Fe ^{3 +} salt compound, from 1 to 10% by weight of nitric acid, from 1 to 30% by weight of acetic acid, from 0.1 to 5% And a multi-layer etchant composition comprising the single layer and the indium oxide layer.

The etchant composition of the present invention is characterized in that a single film of silver (Ag) or silver alloy and a multiple film composed of the single film and the indium oxide film can be simultaneously etched.

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

The Fe ^{3 +} salt compound contained in the etchant composition of the present invention is a component used as a main oxidizing agent and serves to wet-etch silver (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. If the amount of the Fe ³⁺ salt compound is less than 1 wt%, the etching rate of the silver film may be lowered and the etching profile may be deteriorated. If the Fe ³⁺ salt content is more than 15 wt% When a triple layer of indium oxide / silver / indium oxide film is etched, the surface layer of silver may be introduced, and silver may be separated from the surface of the substrate by heat treatment in a subsequent process, causing re-adsorption.

The Fe ^{3 +} salt compound is available in the form of a salt, including the Fe ^{3 +,} its kind is not particularly limited, and specific examples include _{FeCl 3, Fe (NO 3)} 3, Fe 2 (SO 4) 3, NH 4 Fe (SO ₄ ) ₂ , Fe (ClO ₄ ) ₃ , and FePO _4. These may be used singly or in combination of two or more.

The nitric acid (HNO ₃ ) contained in the etchant composition of the present invention is a component used as a co-oxidant and performs a wet etching by oxidizing silver and indium oxide. The content of the nitric acid (HNO ₃ ) is 1 to 10% by weight based on the total weight of the composition. When the content of nitric acid is less than 1% by weight, the etching rate of the silver (Ag) film and the indium oxide film is lowered, resulting in unevenness of etch uniformity in the substrate, resulting in unevenness. For example, when the triple films of indium oxide / silver film / indium oxide film are etched, the etching speed of the indium oxide film is accelerated in the upper and lower portions, and the undercuts of the upper and lower indium oxide films are disadvantageous.

Acetic acid (CH ₃ COOH) contained in the etchant composition of the present invention is a component used as a co-oxidant and performs a wet etching by oxidizing silver (Ag). The acetic acid content is 1 to 30% by weight based on the total weight of the etchant composition. When the content of acetic acid is less than 1% by weight, unevenness in etching rate in the substrate may cause unevenness. When the content of acetic acid exceeds 30% by weight, bubbles are generated. When such bubbles are present in the substrate, Which can cause problems in subsequent processes.

The monosodium phosphate contained in the etchant composition of the present invention is a component used as an additive, and plays a role of controlling the CD skew of the thin film during wet etching and uniformizing the etching. The content of the first sodium phosphate is 0.1 to 5% by weight based on the total weight of the composition. If the content of the first sodium phosphate is less than 0.1% by weight, the uniformity of the etchant in the substrate is lowered. If the content of the first sodium phosphate is more than 5% by weight, the etch rate is lowered, Water may be generated, which may cause a problem in the process.

The water contained in the etchant composition of the present invention is not particularly limited, but deionized water is preferred. In particular, it is more preferable to use deionized water having a resistivity value of water (i.e., the degree of removal of ions in water) of 18 M? / Cm or more. The content of water is in the range of 40 to 96.9% by weight based on the total weight of the composition, and the content is the sum of water contained in the other components added in the form of aqueous solution and water alone.

The etchant composition of the present invention may further contain conventional additives in addition to the above-mentioned components. Examples of the additives include surfactants, sequestering agents, corrosion inhibitors, and pH adjusters.

In the etching solution composition of the present invention, the Fe ^{3 +} salt compound, nitric acid, acetic acid, and sodium phosphate monobasic acid can be prepared by a commonly known method, and particularly preferably have purity for semiconductor processing.

According to the present invention,

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

(ii) etching the one or a plurality of the formed films with the etchant composition of the present invention.

The method for forming a metal pattern according to claim 1, wherein the step (i) comprises the steps of: providing a substrate; depositing a single film of silver (Ag) or silver alloy on the substrate and a multi- And forming one or more selected ones. The substrate may be a wafer, a glass substrate, a stainless steel substrate, a plastic substrate, or a quartz substrate. As a method for forming a single layer of silver (Ag) or silver alloy on the substrate and a multi-layered film composed of the single layer and the indium oxide layer, various methods known to those skilled in the art can be used, and a vacuum deposition method or a sputtering method .

In the step (ii), a photoresist is formed on one or a plurality of films formed in step (i), selectively exposing the photoresist using a mask, baking the exposed photoresist, The post-baked photoresist is developed to form a photoresist pattern. The one or more films on which the photoresist pattern is formed are etched using the etchant composition of the present invention to complete the metal pattern.

Also,

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, the method comprising the steps of:

Wherein at least one of the steps a), d), and e) is formed of a silver or silver alloy monolayer, and a multi-layer film composed of the single film and the indium oxide film And etching each of the electrodes with the etchant composition of the present invention to form respective electrodes. The present invention also provides a method of manufacturing an array substrate for a liquid crystal display device.

In the method of manufacturing an array substrate for a liquid crystal display according to the present invention, the step (a) may include: a1) forming a silver or silver alloy monolayer on the substrate using a vapor deposition method or a sputtering method, Depositing one or more selected from among multiple films consisting of films; And a2) patterning the one or a plurality of the films formed in the above process with the etching solution 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 the above-described examples.

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

In the method for manufacturing an array substrate for a liquid crystal display according to the present invention, in the step c), a semiconductor layer is formed on the gate insulating layer by a chemical vapor deposition method (CVD). That is, an active layer and an ohmic contact layer are sequentially formed, and patterned through 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 the present invention is not limited thereto.

In the method for manufacturing an array substrate for a liquid crystal display according to the present invention, the step d) includes the steps of: 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 films and multiple films composed of the single film and the indium oxide film are deposited on the ohmic surface layer by sputtering and then etched with the etching solution of the present invention, Thereby forming an electrode and a drain electrode. Here, the method of forming the one or more films on the substrate is not limited to the above-described examples. Wherein d2) step, including the inorganic insulating group, or benzocyclobutene (BCB) and acrylic (acryl) resins (resin) containing silicon nitride (SiN _x) and silicon oxide (SiO ₂₎ on the source and drain electrodes The organic insulating material is selected from the group of organic insulating materials to form an insulating layer as a single layer or a double layer. The material of the insulating layer is not limited to those illustrated above.

In the method of manufacturing an array substrate for a liquid crystal display according to the present invention, the pixel electrode connected to the drain electrode is formed in step e). For example, one or a plurality of silver or silver alloy single films and multiple films composed of the single film and the indium oxide film are deposited by sputtering and then etched by the etching solution composition of the present invention to form a pixel electrode . The method of depositing the indium oxide film is not limited to the sputtering method.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples and comparative examples are provided for illustrating the present invention, and the present invention is not limited by the following examples and comparative examples, and various modifications and changes may be made.

Example  1 to 5: Etchant  The preparation of the composition and Etching  Character rating

The a-ITO / Ag / a-ITO triplet was formed on the substrate and cut into 10 × 10 mm using a diamond knife to prepare a specimen. The etching solution was prepared to be 10 kg at the composition ratio shown in Table 1. The etching solution prepared in a spray-type etching system (manufactured by SEMES) was placed and heated at a temperature of 40 ° C. and then etched when the temperature reached 40 ± 0.1 ° C. The total etch time was 50% over etch based on end point detection (EPD).

The substrates were taken out after etching, washed with deionized water, dried using a hot air drying apparatus, and photoresist was removed using a photoresist (PR) stripper. After cleaning and drying, side etching, bottom film damage, and etching property of the etching residue were evaluated using an electron microscope (SEM; model name: S-4700, manufactured by HITACHI Corporation). The results of the etching characteristics test are shown in Table 1 below.

Example Composition (% by weight)
NH4Fe (SO4) 2 / nitric acid / acetic acid / NaH ₂ PO ₄ / water Etch characteristics results Side Etch (占 퐉) Underlying membrane damage The residue One 3/5/20 / 0.5 / 71.5 0.30 radish radish 2 5/4/20 / 1.0 / 70 0.30 radish radish 3 5/7/15 / 1.5 / 71.5 0.40 radish radish 4 6/6/10/1/77 0.43 radish radish 5 7/4/20/2/67 0.50 radish radish

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, lower film damage, And exhibits good etching properties in all respects.

An SEM photograph of the a-ITO / Ag / ITO triple layer after etching the triple layer of the a-ITO / Ag / ITO using the etchant composition of Example 2 is shown in Fig. Further, an a-ITO / Ag / ITO triplet was etched using the etchant composition of Example 2, and an SEM photograph of the substrate surface after stripping the photoresist was attached to Fig. 1B.

Comparative Example  1 to 3: Etchant  The preparation of the composition and Etching  Character rating

The a-ITO / Ag / a-ITO triple layer was formed on the substrate and cut into 10 × 10 mm using a diamond knife. The etching solution was prepared to be 10 kg at the composition ratio shown in Table 2. The etching solution prepared in a spray-type etching system (manufactured by SEMES) was placed and heated at a temperature of 40 ° C. and then etched when the temperature reached 40 ± 0.1 ° C. The total etch time was 50% over etch based on end point detection (EPD).

The substrates were taken out after etching, washed with deionized water, dried using a hot air drying apparatus, and photoresist was removed using a photoresist (PR) stripper. After cleaning and drying, side etching, bottom film damage, and etching property of the etching residue were evaluated using an electron microscope (SEM; model name: S-4700, manufactured by HITACHI Corporation). The results of the etching characteristics test are shown in Table 2 below.

Comparative Example Composition (% by weight)
NH ₄ Fe (SO ₄ ) ₂ / nitric acid / acetic acid / NaH ₂ PO ₄ / water Etch characteristics results Side Etch (占 퐉) Underlying membrane damage The residue One 5/0/15 / 1.0 / 79 Unetch radish U 2 20/2/20 / 1.5 / 56.5 Pattern disappearance radish radish 3 7/2/15/6/70 Unetch radish U

As it can be seen from Table 2, in the case of Comparative Example 1 that does not contain nitric acid, and the upper and lower a-ITO and silver etching rate decreases occurred the etching residue invention the content of NH ₄ Fe (SO _{4) 2} the , The etching rate was excessively increased and the pattern disappeared. In the case of Comparative Example 3 in which the content of sodium monophosphate exceeded the range of the present invention, silver etch residues were generated.

An SEM photograph of the a-ITO / Ag / ITO triple layer after etching the triple layer of the a-ITO / Ag / ITO using the etchant composition of Comparative Example 3 is shown in Fig. Further, an a-ITO / Ag / ITO triplet was etched using the etchant composition of Comparative Example 3, and an SEM photograph of the surface of the substrate after stripping the photoresist was attached to Fig. 2B.

1A is an SEM photograph of an a-ITO / Ag / ITO triple film etched using the etchant composition of Example 2. FIG.

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

2A is an SEM photograph of an a-ITO / Ag / ITO triple layer etched using the etchant composition of Comparative Example 3,

2B is an SEM photograph of the substrate surface after etching the a-ITO / Ag / ITO triple layer using the etchant composition of Comparative Example 3 and stripping the photoresist.

Claims (7)

Wherein the composition comprises 1 to 15% by weight of an Fe ³⁺ salt compound, 1 to 10% by weight of nitric acid, 1 to 30% by weight of acetic acid, 0.1 to 5% by weight of sodium phosphate monobasic and 40 to 96.9% Silver or silver alloy, and an indium oxide film. The method of claim 1, wherein the Fe ³⁺ salt The compound is at least one 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 And an indium oxide film. The composition of claim 1, The etchant composition of claim 1, wherein the etchant composition further comprises at least one additive selected from the group consisting of an etch control agent, a surfactant, a sequestering agent, a corrosion inhibitor, and a pH adjuster. Film and an indium oxide film. Forming one or more selected from a single film of silver (Ag) or silver alloy on the substrate and a multiple film consisting of the single film and the indium oxide film; And Etching the one or more films formed in the above with the etching composition of any one of claims 1 to 3. 5. The method of claim 4, further comprising forming a photoresist pattern on the formed film or films. 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, the method comprising the steps of: Wherein at least one of the steps a), d), and e) is formed of a silver or silver alloy monolayer and a multilayer composed of the single film and the indium oxide film; And etching each of the electrodes with the etching liquid composition according to any one of claims 1 to 3 to form respective electrodes. 7. The method of manufacturing an array substrate for a liquid crystal display according to claim 6, wherein the array substrate for a liquid crystal display is a thin film transistor (TFT) array substrate.

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