KR20230078292A - Composition for etching indium metal oxide layer and method of forming pattern using the same - Google Patents

Abstract

According to embodiments of the present invention, the indium metal oxide film etchant composition includes 6% to 12% by weight of a nitric acid-based oxidizing agent, 1.5% to 7% by weight of a bisulfate-based compound, and 0.1% to 9% by weight of a cyclic amine, based on the total weight of the composition. % by weight, and the remainder including water. An indium metal oxide layer pattern may be formed using the etchant composition without damaging the metal layer or the ITO layer.

Description

Indium metal oxide film etchant composition and pattern formation method using the same

The present invention relates to an indium metal oxide film etchant composition and a pattern forming method using the same. More specifically, it relates to an indium metal oxide film etchant composition including an oxidative etching agent and an additional agent, and a pattern forming method using the same.

For example, a thin film transistor (TFT) array substrate of an image display device includes various electrodes such as pixel electrodes, common electrodes, data lines, scan lines, and power lines, and conductive patterns such as wires.

The conductive patterns may be formed of a low-resistance metal layer such as copper, tungsten, molybdenum, aluminum, and the like, thereby improving driving characteristics and response speed of an image display device.

The conductive patterns may include an indium metal oxide layer including indium tin oxide (ITO), indium zinc oxide (ITO), indium gallium zinc oxide (IGZO), or the like for transparency and protection of a metal layer in an image display device.

Accordingly, an etchant composition having etching characteristics for the indium metal oxide layer is used to form the conductive pattern.

Also, depending on the use of the indium metal oxide layer, an etching process having selectivity only for the indium metal oxide layer may be applied without damaging the metal layer.

Also, when the indium metal oxide layer includes a plurality of layers including different materials, an etching process in which only a layer including a specific material has selectivity may be applied.

As described above, there is a need for an etchant composition capable of realizing selectivity of the etching process depending on the use and position to which the indium metal oxide film is applied.

For example, Korean Patent Publication No. 10-2019-0027019 discloses an etchant composition for forming a conductive pattern of a TFT array substrate. However, an etchant composition having selectivity for an indium metal oxide film is not disclosed.

Korean Patent Publication No. 10-2019-0027019

One object of the present invention is to provide an indium metal oxide film etchant composition having improved etching selectivity and etching efficiency.

One object of the present invention is to provide a method of forming a pattern including indium metal oxide using the etchant composition.

1. Based on the total weight of the composition, 6% to 12% by weight of a nitric acid-based oxidizing agent; 1.5% to 7% by weight of a bisulfate-based compound; 0.1% to 9% by weight of a cyclic amine; And an indium metal oxide film etchant composition comprising a residual amount of water.

2. The indium metal oxide film etchant composition according to 1 above, wherein the bisulfate-based compound includes ammonium bisulfate.

3. The method of 1 above, wherein the cyclic amine is a pyrrole-based compound, a pyrazole-based compound, an imidazole-based compound, a triazole-based compound, or a tetrazole-based compound At least one selected from the group consisting of pentazole-based compounds, oxazole-based compounds, isoxazole-based compounds, diazole-based compounds and isothiazole-based compounds Containing, indium metal oxide film etchant composition.

4. The indium metal oxide film etchant composition according to 3 above, wherein the cyclic amine includes benzotriazole.

5. The indium metal oxide film etchant composition according to 1 above, wherein the content of the nitric acid-based oxidizing agent is 7% to 10% by weight of the total weight of the composition.

6. The indium metal oxide film etchant composition according to 1 above, wherein the content of the bisulfate-based compound is 2% to 6% by weight of the total weight of the composition.

7. The indium metal oxide film etchant composition according to 1 above, wherein the content of the cyclic amine is 0.1% to 5% by weight of the total weight of the composition.

8. The indium metal oxide film etchant composition according to 1 above, which does not contain sulfuric acid and halogen-containing compounds.

9. The indium metal oxide etchant composition according to 1 above, which is used for selective etching of indium zinc oxide (IZO) or amorphous indium tin oxide (a-ITO).

10. Forming an indium metal oxide film on the substrate; and partially etching the indium metal oxide film using the indium metal oxide etchant composition of the above-described embodiments.

11. The method of 10 above, further comprising forming a metal pattern on the substrate before forming the indium metal oxide film, wherein the indium metal oxide film is made of indium zinc oxide (IZO), indium tin oxide (ITO) or A method of forming a pattern comprising indium gallium zinc oxide (IGZO), wherein the partially etching the indium metal oxide layer comprises selectively etching only the indium metal oxide layer with respect to the metal pattern.

12. The method of 10 above, further comprising forming an electrode including an ITO layer on the substrate before forming the indium metal oxide film, wherein the indium metal oxide film is formed to cover the electrode using IZO wherein the partially etching the indium metal oxide layer comprises selectively etching only the indium metal oxide layer with respect to the ITO layer.

13. In the above 12, the electrode is formed to have a sequentially stacked structure of a first ITO layer, a metal layer, and a second ITO layer, and the partially etching the indium metal oxide film exposes the upper surface of the second ITO layer A method of forming a pattern, comprising forming an opening to do so.

An indium metal oxide film etchant composition according to embodiments of the present invention includes nitric acid, a bisulfate compound, and a cyclic amine compound, and may have improved etching selectivity for an indium metal oxide film compared to a metal layer.

Accordingly, the indium metal oxide film can be selectively etched without damaging metal wires and metal electrodes included in the thin film transistor (TFT) array substrate of the image display device.

In some embodiments, the etchant composition may have improved etch selectivity to indium zinc oxide (IZO) or amorphous indium tin oxide (a-ITO). Accordingly, when a plurality of types of indium metal oxide films including different materials are present, a selective etching process may be implemented on a layer including IZO and/or a-ITO.

1 and 2 are schematic cross-sectional views for explaining a pattern forming method according to some exemplary embodiments.
3 and 4 are schematic cross-sectional views for explaining a pattern forming method according to some exemplary embodiments.
5A is an image of an IZO layer etched using the etchant composition of Example 1.
Figure 5b is an image of the upper surface of the ITO layer after performing an etching process using the etchant composition of Example 1.
6 is an image of an IZO layer subjected to an etching process using the etchant composition of Comparative Example 7;
7a and 7b are images showing damage to the upper surface of the ITO layer in Comparative Examples 2 and 5, respectively.

Embodiments of the present invention provide an indium metal oxide etchant composition comprising a nitric acid-based oxidizing agent and an additional agent and having improved etch selectivity. In addition, embodiments of the present invention provide a pattern forming method with improved mechanical reliability using the indium metal oxide etchant composition.

For example, the indium metal oxide etchant composition may be applied to an etching process for forming a pixel structure or a pixel array of an image display device.

Hereinafter, embodiments of the present invention will be described in detail.

<Indium metal oxide etchant composition>

An indium metal oxide etchant composition (hereinafter, may be abbreviated as an etchant composition) according to example embodiments may include a nitric acid-based oxidizing agent, a bisulfate-based compound, and a cyclic amine.

The nitric acid-based oxidizing agent may be used as a main etching agent that initiates etching of the indium metal oxide layer by inducing a substitution reaction in the indium metal oxide layer. Nitric acid and/or nitrous acid may be used as the nitric acid-based oxidizing agent.

The content of the nitric acid-based oxidizing agent may be 6% to 12% by weight of the total weight of the etchant composition. When the amount of the nitric acid-based oxidizing agent is less than 6% by weight, substantial etching characteristics for the indium metal oxide film may not be implemented.

When the amount of the nitric acid-based oxidizing agent exceeds 12% by weight, the etching rate may be excessively increased and the etching process may not be substantially controlled. In addition, an increase in the content of nitrogen components in the composition may cause environmental pollution issues.

Preferably, the content of the nitric acid-based oxidizing agent may be 7 wt% to 10 wt%, more preferably 8 wt% to 10 wt%, or 8 wt% to 9.5 wt%.

According to exemplary embodiments, the bisulfate-based compound may act as an auxiliary etching agent replacing sulfuric acid. Accordingly, it is possible to provide a sufficient etching rate while avoiding environmental pollution and metal layer corrosion caused by sulfuric acid.

In addition, when the bisulfate-based compound is used in an appropriate amount, it may act as an etch control agent for indium tin oxide (ITO). Accordingly, the etchant composition may have an improved etch selectivity to IZO or a-ITO.

The bisulfate-based compound may have a larger molecular size and molecular weight than, for example, a sulfate-based compound. Accordingly, the bisulfate-based compound may control the rate of the substitution reaction induced by the nitric acid-based oxidizing agent through steric hindrance.

In some embodiments, the bisulfate-based compound may include ammonium bisulfate. In this case, the anti-corrosion effect through the bisulfate-based compound may be enhanced.

The content of the bisulfate-based compound may be 1.5 wt % to 7 wt % based on the total weight of the composition. When the amount of the bisulfate-based compound is less than 1.5% by weight, the overall etching rate may also decrease. When the amount of the bisulfate-based compound exceeds 7% by weight, the etching rate of ITO increases and the etching selectivity of IZO may decrease.

Preferably, the content of the bisulfate-based compound may be 2% to 6% by weight, more preferably 3% to 6% by weight.

The cyclic amine may act as a corrosion inhibitor or an etch inhibitor for a metal layer. The cyclic amine is a pyrrole-based compound, a pyrazole-based compound, an imidazole-based compound, a triazole-based compound, a tetrazole-based compound, or a pentazole-based compound. compound, an oxazole-based compound, an isoxazole-based compound, a diazole-based compound, an isothiazole-based compound, and the like. These may be used alone or in combination of two or more.

In one embodiment, benzotriazole may be used as the triazole-based compound. As the tetrazole-based compound, 5-aminotetrazole, 3-aminotetrazole, 5-methyltetrazole and/or 5-aminotetrazole may be used.

In a preferred embodiment, benzotriazole may be used as the cyclic amine compound.

The content of the cyclic amine compound may be 0.1% to 9% by weight of the total weight of the composition. If the amount of the cyclic amine compound is less than 0.1% by weight, corrosion and etching damage of the metal layer may be caused. When the amount of the cyclic amine compound exceeds 9% by weight, the etching rate of IZO or a-ITO may decrease.

Preferably, the content of the cyclic amine compound may be 0.1 wt% to 5 wt%, more preferably 0.1 wt% to 2 wt%, or 0.1 wt% to 1 wt%.

The etchant composition may further include water (eg, deionized water (DIW)). For example, water may be included in an amount or in excess of the remaining components of the composition.

As used in this application, the terms "surplus" or "remaining amount" can refer to a variable amount that changes with the addition of ingredients or agents.

As described above, the etchant composition may have an improved etching selectivity to indium metal oxide (eg, IZO or a-ITO) while increasing an etching rate by using a bisulfate compound instead of sulfuric acid.

Accordingly, the etchant composition may not include sulfuric acid.

In some embodiments, the etchant composition may use only the nitric acid-based oxidizing agent as an acid component. For example, the etchant composition may not include fruit water, hydrochloric acid, sulfuric acid, hydrofluoric acid, or organic acid.

Accordingly, corrosion of the metal layer and environmental pollution may be suppressed while securing an etching rate/etch selectivity for indium metal oxide.

In some embodiments, the etchant composition may not include a halogen-containing compound. Accordingly, etching selectivity to indium metal oxide can be further improved while preventing etching damage to the metal layer by the halogen component.

As described above, the etchant composition may be used in a selective etching process for an indium metal oxide layer.

In one embodiment, when the indium metal oxide film is a single layer including ITO, IZO, or IGZO, the indium metal oxide film is formed while suppressing damage to the metal layer including Ag, Cu, Al, Mo, Ti, W, and the like. It can be selectively etched using the etchant composition.

In one embodiment, as described above, the etchant composition may have strong etching characteristics for IZO or a-ITO among indium metal oxides. Accordingly, when the indium metal oxide film includes a plurality of layers of different materials such as IZO, ITO (poly-ITO), and IGZO, the etchant composition may be used to selectively etch the IZO layer.

<Pattern formation method>

1 and 2 are schematic cross-sectional views for explaining a pattern forming method according to some exemplary embodiments.

Referring to FIG. 1 , a buffer layer 110 may be formed on a substrate 100 .

The substrate 100 may include a glass substrate or a flexible resin substrate such as polyimide. The substrate 100 may include a semiconductor substrate such as a silicon wafer.

The buffer layer 110 may include, for example, silicon oxide, silicon nitride, or silicon oxynitride. The lower insulating layer 110 may be formed through a deposition process such as, for example, a chemical vapor deposition (CVD) process or a physical vapor deposition (PVD) process.

Thereafter, after forming a metal layer on the buffer layer 110 , the metal layer may be etched to form the metal pattern 120 . For example, the metal pattern 120 may include various electrodes or wires of a TFT array substrate included in an image display device.

An indium metal oxide layer 130 may be formed on the buffer layer 110 . For example, the indium metal oxide layer 130 may be formed to cover the metal pattern 120 .

In some embodiments, the indium metal oxide layer 130 may be formed as a single layer including ITO, IZO, or IGZO.

Referring to FIG. 2 , the indium metal oxide layer 130 may be partially etched using the etchant composition according to the exemplary embodiments described above. Accordingly, the indium metal oxide layer pattern 135 may be formed.

As described above, the etchant composition has an improved etching selectivity to indium metal oxide and can suppress etching damage of the metal pattern 120 .

3 and 4 are schematic cross-sectional views for explaining a pattern forming method according to some exemplary embodiments.

Referring to FIG. 3 , a buffer layer 110 may be formed on a substrate 100 and an electrode 140 may be formed on the buffer layer 110 .

The electrode 140 may be a multilayer electrode including an indium metal oxide layer and a metal layer. In some embodiments, the electrode 140 may have a multi-layer structure in which a first ITO layer 142 , a metal layer 145 , and a second ITO layer 144 are sequentially stacked.

For example, the electrode 140 may be a pixel electrode of a TFT array substrate. For example, the electrode 140 may be electrically connected to the drain electrode of the TFT.

After that, an indium metal oxide layer 150 covering the electrode 140 may be formed on the buffer layer 110 . According to example embodiments, the indium metal oxide layer 150 may be formed using IZO.

Referring to FIG. 4 , the indium metal oxide layer 150 may be partially etched using the etchant composition according to the exemplary embodiments described above. Accordingly, the indium metal oxide layer pattern 155 including the opening 160 exposing the upper surface of the electrode 140 (the upper surface of the second ITO layer 144 ) may be formed.

As described above, the etchant composition may have improved etch selectivity for IZO versus ITO. Accordingly, only the indium metal oxide layer 150 including IZO may be selectively etched without damaging the upper surface of the second ITO layer 144 .

Hereinafter, experimental examples including specific examples and comparative examples are presented to aid understanding of the present invention, but these are only illustrative of the present invention and do not limit the scope of the appended claims, and the scope and technical spirit of the present invention It is obvious to those skilled in the art that various changes and modifications to the embodiments are possible within the scope, and it is natural that these changes and modifications fall within the scope of the appended claims.

Examples and Comparative Examples

As shown in Table 1 below, the components were mixed in the remaining amount of water in the corresponding content (wt%) to prepare the etchant compositions of Examples and Comparative Examples.

nitric acid acetic acid Benzotriazole ammonium
bisulfate ammonium
sulfate Example 1 9.5 - 0.5 5.0 - Example 2 9.0 - 0.5 5.0 - Example 3 9.0 - 0.5 6.0 - Example 4 8.5 - 0.5 5.0 - Example 5 8.5 - 0.5 6.0 - Example 6 8.0 - 0.5 5.0 - Example 7 8.0 - 0.5 6.0 - Example 8 8.0 1.0 0.5 5.0 - Comparative Example 1 5 - 0.5 6.0 - Comparative Example 2 13 - 0.5 5.0 - Comparative Example 3 5.0 - 0.5 10.0 - Comparative Example 4 9.0 - 0.5 1.0 - Comparative Example 5 9.0 - 0.5 8.0 - Comparative Example 6 9.0 - 10 5.0 - Comparative Example 7 - - 0.5 5.0 - Comparative Example 8 9.0 - 0.5 - - Comparative Example 9 9.0 - - 5.0 - Comparative Example 10 9.0 - - 5.0 0.5

Experimental example

(1) Evaluation of indium metal oxide film etching characteristics

Samples were prepared in which an IZO film and an a-ITO film each having a thickness of 100 Å were formed on a glass substrate, and photoresist patterns were formed on the IZO film and the a-ITO film. The IZO film was etched with the etching compositions of Examples and Comparative Examples using the photoresist pattern as a mask.

Specifically, after filling 10 kg of the etchant composition into a wet etching equipment, the prepared sample was etched for 80 seconds by adjusting to a temperature of 40 ° C.

(2) ITO damage evaluation

An electrode having an ITO/silver (Ag)/ITO stack structure (100 Å/1000 Å/100 Å) was formed on a glass substrate. A 100 Å-thick IZO film covering the electrode was formed on the substrate, and an etching process was performed on the IZO film to expose the upper ITO layer of the electrode in the same manner as in (1).

(3) Metal layer damage evaluation

A Cu film, an Ag film, and an Al film each having a thickness of 100 Å were formed on a glass substrate, an IZO film having a thickness of 100 Å was formed on the metal film, and an etching process for the IZO film was performed in the same manner as in (1).

After the etching process in (2) and (3) above, damage to the surface of the ITO layer, Cu film, Ag film and Al film was observed and evaluated as follows.

○: No etching damage

△: observed partial surface damage

×: observed damage across the entire surface

The evaluation results are shown in Table 2 below.

division Etch Characteristics ITO
damaged damage to the metal layer IZO a-ITO Cu Ag Al Example 1 0.71 0.31 ○ ○ ○ ○ Example 2 0.71 0.32 ○ ○ ○ ○ Example 3 0.71 0.31 ○ ○ ○ ○ Example 4 0.71 0.31 ○ ○ ○ ○ Example 5 0.72 0.31 ○ ○ ○ ○ Example 6 0.72 0.31 ○ ○ ○ ○ Example 7 0.71 0.31 ○ ○ ○ ○ Example 8 0.75 0.33 ○ △ △ △ Comparative Example 1 - - ○ ○ ○ ○ Comparative Example 2 0.80 0.39 × ○ ○ ○ Comparative Example 3 - - × ○ ○ ○ Comparative Example 4 0.21 0.10 ○ ○ ○ ○ Comparative Example 5 0.75 0.35 × ○ ○ ○ Comparative Example 6 0.64 0.24 ○ ○ ○ ○ Comparative Example 7 - - ○ ○ ○ ○ Comparative Example 8 - - ○ ○ ○ ○ Comparative Example 9 0.71 0.31 ○ × ○ ○ Comparative Example 10 0.70 0.30 △ △ △ △

Referring to Table 2, in the embodiments including nitric acid, ammonium bisulfate, and benzotriazole in predetermined amounts, respectively, damage to ITO and the metal layer was prevented while securing improved etching rates for IZO and a-ITO.

Referring to FIG. 5A , it can be confirmed that the IZO layer was properly side-etched under the photoresist pattern using the etchant composition of Example 1.

Referring to Figure 5b, through the etchant composition of Example 1, the IZO layer was removed without damaging the surface of the ITO layer through the opening was formed.

In the case of Example 8 in which the organic acid was added, partial damage of the metal layer was observed.

As in Comparative Example 1, Comparative Example 3, Comparative Example 7, and Comparative Example 8, when nitric acid or ammonium bisulfate was not included or did not satisfy an appropriate content range, etching performance for IZO and a-ITO was not implemented.

For example, referring to FIG. 6, when the etchant composition of Comparative Example 7 was used, the IZO layer was not substantially etched.

Referring to Comparative Examples 2 and 5, when nitric acid or ammonium bisulfate was excessively included, surface damage was observed on the top surface of the ITO layer, as shown in FIGS. 7A and 7B , respectively.

When benzotriazole was not included as in Comparative Example 9, damage to the metal layer was observed, and when benzotriazole was excessively contained as in Comparative Example 6, the etching rate was reduced.

In Comparative Example 10, since ammonium sulfate was used instead of ammonium bisulfate, the protective effect on ITO and the metal layer was not implemented, and precipitation of the composition was additionally observed.

100: substrate 110: buffer layer
120: metal pattern 130, 150: indium metal oxide film
135, 155: indium metal oxide film pattern
140: electrode 142: first ITO layer
144: second ITO layer 145: metal layer

Claims (13)

Of the total weight of the composition,
6% to 12% by weight of a nitric acid-based oxidizing agent;
1.5% to 7% by weight of a bisulfate-based compound;
0.1% to 9% by weight of a cyclic amine; and
An indium metal oxide film etchant composition comprising a residual amount of water.
The indium metal oxide etchant composition of claim 1, wherein the bisulfate-based compound includes ammonium bisulfate.
The method according to claim 1, wherein the cyclic amine is a pyrrole-based compound, a pyrazole-based compound, an imidazole-based compound, a triazole-based compound, a tetrazole-based compound, or a pentachloride compound. Containing at least one selected from the group consisting of pentazole-based compounds, oxazole-based compounds, isoxazole-based compounds, diazole-based compounds and isothiazole-based compounds , Indium metal oxide film etchant composition.
The indium metal oxide etchant composition of claim 3, wherein the cyclic amine includes benzotriazole.
The method according to claim 1, Of the total weight of the composition, the content of the nitric acid-based oxidizing agent is 7% by weight to 10% by weight, the indium metal oxide film etchant composition.
The indium metal oxide etchant composition of claim 1, wherein the content of the bisulfate-based compound is 2% to 6% by weight, based on the total weight of the composition.
The method according to claim 1, Of the total weight of the composition, the content of the cyclic amine is 0.1% to 5% by weight, the indium metal oxide film etchant composition.
The indium metal oxide film etchant composition according to claim 1, which does not contain sulfuric acid and halogen-containing compounds.
The indium metal oxide etchant composition according to claim 1, which is used for selective etching of indium zinc oxide (IZO) or amorphous indium tin oxide (a-ITO).
Forming an indium metal oxide film on the substrate; and
A pattern forming method comprising the step of partially etching the indium metal oxide film using the indium metal oxide film etchant composition of claim 1.
The method according to claim 10, further comprising forming a metal pattern on the substrate before forming the indium metal oxide film,
The indium metal oxide film includes indium zinc oxide (IZO), indium tin oxide (ITO) or indium gallium zinc oxide (IGZO),
Wherein the partially etching the indium metal oxide layer comprises selectively etching only the indium metal oxide layer with respect to the metal pattern.
The method according to claim 10, further comprising forming an electrode including an ITO layer on the substrate before forming the indium metal oxide film,
The indium metal oxide film is formed to cover the electrode using IZO,
Wherein the partially etching the indium metal oxide film comprises selectively etching only the indium metal oxide film with respect to the ITO layer.
The method according to claim 12, wherein the electrode is formed to have a sequential stacking structure of a first ITO layer, a metal layer and a second ITO layer,
The partially etching the indium metal oxide layer includes forming an opening exposing an upper surface of the second ITO layer.

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