KR101347455B1 - Etchant composition for an Indium based oxide layer and method for fabricating metal pattern using the same - Google Patents

Abstract

The present invention is based on the total weight of the composition H ₂ SO ₄ 1 to 15% by weight; HF 0.01-2 wt%; 0.01 to 5% by weight of one or more salt compounds selected from ammonium salts, potassium salts and phosphates; And an indium oxide film etching liquid composition comprising 78 to 98.98 wt% of water, a method of forming a metal pattern using the same, and a method of manufacturing an array substrate for a liquid crystal display using the same.

Transparent conductive film, indium, liquid crystal display, etchant

Description

Etchant composition for an Indium based oxide layer and method for fabricating metal pattern using the same}

The present invention relates to an etching liquid composition of an indium oxide film used as a transparent electrode in a flat panel display device, 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.

Thin films such as IZO and a-ITO are called Thin Film of Transparent Conductive Oxides. In general, these films have a transmittance of about 90% or more in the visible region and resistivity of 1 × 10 ^-4 Ω㎝ or less. Have In order for the transparent conductive film to be transparent, there should be few conductive electrons, and for the electrical conductivity to be large, the conductive electrons must be large. In the case of a transparent conductive film, these two opposite conditions must be satisfied.

Sputtering is generally used to deposit IZO and a-ITO. Compared with CVD (Chemical Vapor Deposition) method, it is easier to control deposition conditions. It has the advantage of being easy to achieve uniformity of properties. When using the sputtering method, there are two methods of using an oxide target or an alloy target. The use of an alloy target has the advantages of high deposition rate, longer target life, ease of manufacture and recycling of the target. However, there is a disadvantage in that the characteristic change is sensitive to process variables. Using an oxide target can control the stoichiometric ratio of the thin film reproducibly, but the deposition rate is slower than that of the alloy target, physical cracks may occur in the target during deposition, and arcs may occur in the target. When indium-based oxides are deposited by sputtering, they react with O ₂ to form In ₂ O _3. Ge, Si, Ti, Sb, Zr, Sn, and Zn are used as dopants to improve electrical conductivity. do.

IZO and a-ITO in the present invention mean a transparent conductive film oxide in which In ₂ O ₃ and ZnO, In ₂ O ₃ and SnO ₂ are mixed at an appropriate ratio.

Although there is a difference depending on the driving of the device of the liquid crystal flat panel display, recently, a top pixel electrode is generally used. After the deposition on the source / drain passivation layer, the photoresist is coated on the pixel electrode layer, a photoresist pattern is formed through an exposure and development process, and an etching process is performed on the substrate on which the pattern is formed using an etching solution. The photoresist is then stripped to form a metal oxide pattern of a desired shape.

The indium oxide film is one of materials that are not easily etched because of excellent chemical resistance. For example, an indium oxide film (HCl + HNO ₃ ) etchant disclosed in Korean Patent Laid-Open No. 1996-2903; An etchant consisting of one substance selected from hydrochloric acid, weak acid and alcohol disclosed in Korean Patent Laid-Open No. 1997-65685; Iron chloride based (FeCl ₃ + HCl) etchant disclosed in US Pat. No. 5,456,795; An etchant including oxalic acid and salts thereof or aluminum chloride disclosed in Korean Patent Laid-Open No. 2000-17470 can be used. In addition, U. S. Patent No. 5,340, 491 discloses an etching solution containing hydrogen iodide (HI) and iron chloride (FeCl ₃ ).

However, in case of aqua regia, the cost is low, but the etching is faster in terms of the pattern, so that the profile is poor and the etchant composition fluctuates over time because the main component hydrochloric acid or nitric acid is easily volatilized. . In addition, in the case of the iron chloride-based etching solution, since the main component is hydrochloric acid, the component fluctuates over time. In addition, even though the etching solution made of oxalic acid is easily etched, there is a problem in that precipitates are generated at low temperatures with low solubility. In addition, the etching solution composed of hydrogen iodide (HI) has a high etching rate and low side etching, but is expensive and expensive and toxic and corrosive.

Meanwhile, the above-described conventional etchant has strong chemical activity, and may cause erosion of adjacent metals such as molybdenum (Mo), aluminum (Al), and chromium (Cr), which have poor chemical resistance during etching. The same applies to the case of the multilayer film structure including one of the above-described metals.

In addition, in the case of the etching solution containing hydrochloric acid, there is a smoke is causing a problem of air pollution due to the fume (fume), thereby causing a problem of the increase of equipment and safety operation.

The present invention shows sufficient etching ability at time and purchase time according to the use of the chemical solution, there is no residue after erosion and etching on the lower layer, and exothermic reaction and precipitation phenomenon by attack on the equipment material and incorporation with other chemical liquids. An object of the present invention is to provide an etching solution composition of an environmentally friendly indium oxide film, 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 based on the total weight of the composition, H ₂ SO ₄ 1 to 15% by weight; HF 0.01-2 wt%; 0.01 to 5% by weight of one or more salt compounds selected from ammonium salts, potassium salts and phosphates; And it provides an indium oxide film etching liquid composition comprising 78 to 98.98% by weight of water.

In addition,

Forming an indium oxide film on the substrate;

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

It provides a method of forming a metal pattern comprising the step of etching the indium oxide film formed in the above step using 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:

The step (e) comprises the step of forming an indium oxide film and the step of forming the pixel electrode by etching the indium oxide film formed in the etching liquid composition of the present invention. To provide.

The etchant composition according to the present invention exhibits sufficient etching ability at time and purchase time according to the use of the chemical solution, there is no erosion of the lower layer and no residue after etching, and there is no attack on the material of the equipment. It provides stability, and there is no exothermic reaction and precipitation phenomenon by incorporation with other chemicals, so it provides stability when the user uses the chemicals, and it is very environmentally friendly, so it shows very excellent process efficiency in etching indium oxide film.

The present invention is based on the total weight of the composition H ₂ SO ₄ 1 to 15% by weight; HF 0.01-2 wt%; 0.01 to 5% by weight of one or more salt compounds selected from ammonium salts, potassium salts and phosphates; And it relates to an indium oxide film etching liquid composition comprising 78 to 98.98% by weight of water.

The etchant composition of the present invention is used to form an indium oxide film wiring used as a transparent electrode in a flat panel display device. Specifically, the etchant composition is an etching composition such as IZO (Indium Zinc Oxide) and a-ITO (Amorphous Indium Tin Oxide). . However, it is not limited to said transparent conductive film.

In the etchant composition of the present invention, H ₂ SO ₄ is a main oxidizing agent for etching IZO and a-ITO. The content of H ₂ SO ₄ is 1 to 15% by weight, preferably 2 to 7% by weight, based on the total weight of the composition. When the H ₂ SO ₄ is less than 1% by weight, the etching rate is lowered and sufficient etching may not be achieved, and residues may occur. When the content is more than 15% by weight, excessive etching, chemical damage to the photoresist may occur, and deformation may occur. In addition, chemical damage may occur to the gate layers and the source / drain interconnects, which may cause shortages, which may cause problems in subsequent processes.

In the etchant composition of the present invention, HF plays a role of controlling the etching rate together with H ₂ SO ₄ . The content of HF is 0.01 to 2% by weight, preferably 0.05 to 1% by weight relative to the total weight of the composition. If HF is less than 0.01% by weight, sufficient etching rate cannot be obtained. If it exceeds 2% by weight, the etching rate increases, but short circuit occurs due to chemical damage to the gate layer and the source / drain wiring, which are the underlying layers. Problems can occur in subsequent processes.

In the etching liquid composition of the present invention, at least one salt compound selected from ammonium salt, potassium salt and phosphate salt is used as an etching inhibitor. The content of at least one salt compound selected from ammonium salts, potassium salts and phosphates is from 0.01 to 5% by weight, preferably from 0.5 to 2% by weight relative to the total weight of the composition.

When the etching inhibitor is less than 0.01% by weight, damage may occur to the lower layer. When the etching inhibitor exceeds 5% by weight, damage to the lower layer may be suppressed, but the etching rate of the transparent conductive film may be lowered to obtain good etching characteristics.

As the ammonium salt, potassium salt and phosphate in the above can be used without limitation, for example, ammonium thiosulfate, ammonium sulfate, ammonium persulfate, ammonium phosphate, ammonium acetate, ammonium nitrate, ammonium borate, ammonium citrate Ammonium oxalate, ammonium formate, ammonium carbonate; Sodium dihydrogen phosphate, sodium nitrate, sodium sulfate, sodium acetate; Potassium dihydrogen phosphate; Potassium acetate, potassium nitrate, potassium sulfate, etc. are mentioned.

In the etchant composition of the present invention, water is not particularly limited, but deionized water is preferable. 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 included in 78 to 98.98% by weight based on the total weight of the composition, the content is the sum of the water alone and the amount of water added in the other components added in the form of an aqueous solution.

In addition to the above-mentioned components, conventional additives may further be added to the etchant composition of the present invention. Surfactants, sequestering agents, corrosion inhibitors, pH adjusters, and the like can be used as additives.

Surfactants decrease the surface tension and increase the uniformity of etching. As such a surfactant, a surfactant which is resistant to an etching solution and has compatibility with the surfactant is preferable. Examples thereof include any anionic, cationic, zwitterionic or nonionic surfactant. Further, a fluorine-based surfactant can be used as a surfactant.

In addition, the additives are not limited thereto, and various other additives known in the art may be selected and added for better effect of the present invention.

In the compositions of the present invention, at least one salt compound selected from H ₂ SO ₄ , HF, and ammonium salts, potassium salts and phosphates can be prepared according to known methods, and in particular, preferably has a purity for semiconductor processing. Do.

The present invention also relates to

Forming an indium oxide film on the substrate;

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

It relates to a method of forming a metal pattern comprising the step of etching the indium oxide film formed in the above step using the etching solution composition of the present invention.

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

The method of forming the metal pattern may be usefully used in the field of manufacturing a TFT array substrate for a liquid crystal display device.

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:

The step (e) comprises the step of forming an indium oxide film and the step of forming the pixel electrode by etching the indium oxide film formed in the etching liquid composition of the present invention. It is about.

The method of manufacturing an array substrate for a liquid crystal display device may be usefully used for a thin film transistor (TFT) array substrate.

In the step e), 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 etched with an etchant composition according to the present invention. Form. The method of depositing the indium oxide film is not limited only to the sputtering method.

In addition, during the e) step etching process using the etchant composition according to the present invention, an attack on a data line including a drain electrode positioned under the pixel electrode can be minimized, thereby improving driving characteristics of the TFT-LCD. It is possible to manufacture an excellent array substrate for a liquid crystal display device, and to improve the productivity of the array substrate for a liquid crystal display device.

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 to 10: Etchant  Preparation of the composition and Etching  Property evaluation

A specimen was prepared by cutting the a-ITO substrate into 10 × 10 mm using a diamond knife. And to prepare an etching solution to 10kg in the composition ratio described 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 transparent conductive film etching time was performed based on 80 seconds in consideration of the actual process time. In addition, to evaluate the damage of the lower layer, the Mo / Al and Mo / Al / Mo substrates with metal wirings were prepared at 10 × 10 mm, and the damage was evaluated by exposing the sprayed etching solution for 5 min. When 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, an electron scanning microscope (SEM; manufactured by HITACHI, model name: S-4700) was used to evaluate the occurrence of residues of the transparent conductive film, the presence of PR attack, and damage to the underlying film. Etch characteristic results are shown in Table 1 below.

Example Composition (% by weight) Etch characteristic evaluation result Sulfuric acid / hydrofluoric acid / CH ₃ COOK / water Residual occurrence Bottom film damage PR Attack One 4 / 0.2 / 2 / 93.8 × × × 2 4.5 / 0.15 / 1 / 94.35 × × × 3 5 / 0.15 / 1.5 / 93.35 × × × 4 5.5 / 0.1 / 2 / 92.4 × × × 5 6 / 0.1 / 1.5 / 92.4 × × × 6 6.5 / 0.08 / 1.0 / 92.42 × × × 7 7 / 0.05 / 1.0 / 91.95 × × × 8 7.5 / 0.05 / 1.5 / 90.95 × × × 9 8 / 0.02 / 1.5 / 90.48 × × × 10 8.5 / 0.02 / 2 / 89.48 × × ×

As can be seen in Table 1, when the indium oxide film is etched using the etchant composition of the present invention, it can be seen that good etching characteristics are exhibited in terms of residue generation, lower layer damage, and PR attack.

In addition, it is possible to confirm good etching characteristics from the SEM photograph of FIG. 1 showing the result of etching the a-ITO membrane using the etchant composition of Example 3, and after etching the a-ITO membrane using the etchant composition of Example 3, It can be seen that there is no damage to the lower layer from the SEM pictures taken for the lower layer damage evaluation, FIG. 3A (Mo / Al thin film) and 3b (Mo / Al / Mo thin film).

Comparative Example  1 to 5: Etchant  Preparation of the composition and Evaluation of etching characteristics

The a-ITO substrate was cut into 10 × 10 mm using a diamond knife to prepare a specimen. And an etching solution was prepared to be 10kg in 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 transparent conductive film etching time was performed based on 80 seconds in consideration of the actual process time. In addition, to evaluate the damage of the lower layer, the Mo / Al and Mo / Al / Mo substrates with metal wirings were prepared at 10 × 10 mm, and the damage was evaluated by exposing the sprayed etching solution for 5 min. When 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, an electron scanning microscope (SEM; manufactured by HITACHI, model name: S-4700) was used to evaluate the occurrence of residues of the transparent conductive film, the presence of PR attack, and damage to the underlying film.

Comparative Example Composition (% by weight) Etch characteristic evaluation result Sulfuric acid / hydrofluoric acid / CH ₃ COOK / water Residual occurrence Bottom film damage PR Attack One 7/0/1/92 ○ × × 2 20 / 0.01 / 1 / 78.99 × ○ ○ 3 6 / 0.01 / 7 / 86.99 ○ × × 4 4/3/2/91 × ○ ○ 5 0 / 0.03 / 1 / 98.97 ○ × ×

As can be seen in Table 2, in the case of Comparative Example 1 without HF, a residue of the a-ITO film was generated, and in the case of Comparative Example 2 in which the sulfuric acid content exceeded the range of the present invention, the etching rate Was improved, but damage occurred to the lower layer and the photoresist. In Comparative Example 3, in which the amount of the etch inhibitor was exceeded, the residue of the a-ITO film was generated, and the HF content was in the range of the present invention. In the case of Comparative Example 4 contained in excess of the etching rate is improved, but the damage to the lower layer and the photoresist occurred, in the case of Comparative Example 5, which does not contain sulfuric acid, the etching rate is lowered, residue was generated.

This fact is confirmed more clearly by the accompanying drawings, Figure 4 can confirm the occurrence of the etching residue as a result of etching the a-ITO film with the food solution composition of Comparative Example 1. 5A and 5B show that the damage occurred to the Mo / Al thin film (FIG. 5A) and the Mo / Al / Mo thin film (FIG. 5B) as the lower film as a result of etching the a-ITO film with the etchant composition of Comparative Example 2. have. 6 shows the occurrence of etching residues as a result of etching the a-ITO film with the food solution composition of Comparative Example 3. 7A and 7B show damage of the Mo / Al thin film (FIG. 7A) and Mo / Al / Mo thin film (FIG. 7B) as a result of etching the a-ITO film with the etchant composition of Comparative Example 4, and PR attack. can confirm. 8 shows the occurrence of the etching residue as a result of etching the a-ITO film with the food solution composition of Comparative Example 5.

1 is a SEM photograph showing the result of etching the a-ITO membrane using the etchant composition of Example 3.

FIG. 2A is a SEM photograph of a Mo / Al thin film in which metallization is formed without damaging a lower layer.

FIG. 2B is a SEM photograph of a Mo / Al / Mo thin film in which metal lines are formed without damaging a lower layer.

3A is a SEM photograph showing the state of the Mo / Al thin film as the lower film after etching the a-ITO film using the etchant composition of Example 3. FIG.

FIG. 3B is a SEM photograph showing the state of the Mo / Al / Mo thin film as the lower layer after etching the a-ITO film using the etchant composition of Example 3. FIG.

4 is a SEM photograph showing a result of etching an a-ITO film using the etchant composition of Comparative Example 1. FIG.

5A is a SEM photograph showing a state of a Mo / Al thin film as a lower film after etching an a-ITO film using the etchant composition of Comparative Example 2. FIG.

FIG. 5B is a SEM photograph showing the state of the Mo / Al / Mo thin film as the lower layer after etching the a-ITO film using the etchant composition of Comparative Example 2. FIG.

6 is a SEM photograph showing the result of etching the a-ITO membrane using the etchant composition of Comparative Example 3.

FIG. 7A is a SEM photograph showing the state of a Mo / Al thin film as a lower film after etching an a-ITO film using the etchant composition of Comparative Example 4. FIG.

FIG. 7B is a SEM photograph showing the state of the Mo / Al / Mo thin film as the lower film after etching the a-ITO film using the etchant composition of Comparative Example 4. FIG.

8 is a SEM photograph showing the result of etching the a-ITO membrane using the etchant composition of Comparative Example 5.

Claims (7)

1 to 15 weight percent H ₂ SO ₄ , based on the total weight of the composition; HF 0.01-2 wt%; 0.01 to 5% by weight of one or more salt compounds selected from the group consisting of ammonium acetate, ammonium citrate, ammonium oxalate, ammonium formate, ammonium carbonate, sodium acetate and potassium acetate; And 78 to 98.98% by weight of water. delete The etchant composition of claim 1, wherein the etchant composition further comprises at least one additive selected from among an etchant, a surfactant, a metal ion sequestrant, a corrosion inhibitor, and a pH regulator. Forming an indium oxide film on the substrate; Selectively leaving a photoreactive material on the indium oxide film; And A method of forming an indium oxide film pattern comprising the step of etching the indium oxide film formed in the step using the etching solution composition of claim 1. 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: The step (e) comprises the step of forming an indium oxide film and the step of forming the pixel electrode by etching the indium oxide film formed in the etching liquid composition of claim 1, wherein the array substrate for a liquid crystal display device. . The method of manufacturing an array substrate for a liquid crystal display device according to claim 5, wherein the array substrate for liquid crystal display device is a thin film transistor (TFT) array substrate. The etchant composition of claim 1 or 3, wherein the indium oxide film is an IZO (Indium Zinc Oxide) film or an amorphous indium tin oxide (a-ITO) film.

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