TWI674311B - Etchant composition, transparent electrode forming method and display substrate manufacturing method - Google Patents

Abstract

The invention discloses an etchant composition. The etchant composition includes: nitric acid, 3 wt% or more and less than 10 wt%; chloride, 0.01 wt% or more and 5 wt% or less; ammonia compounds, 0.1 wt% or more And 5 wt% or less; cyclic amino compounds, 0.1 wt% or more and 5 wt% or less; the remaining wt% of water. Accordingly, the metal oxide layer including copper, titanium, molybdenum, or aluminum can be prevented from being etched by selectively etching the metal oxide layer.

Description

Etchant composition, method for forming transparent electrode, and display substrate Plate manufacturing method

The present invention relates to an etchant composition, a method for forming a transparent electrode using the same, and a method for manufacturing a display substrate, and more particularly, to an etchant component capable of etching a metal oxide layer, a transparent electrode using the same, and a display substrate. Production method.

Generally, a display substrate for a display device includes a thin film transistor as a switching element for driving each pixel region, a signal line connected to the thin film transistor, and a pixel electrode. The signal line includes: a gate line that transmits a driving signal of the gate; and a data line that crosses the gate line and transmits a data driving signal.

The pixel electrode includes a metal oxide such as indium tin oxide, indium zinc oxide, and the like, and in order to form the pixel electrode, an etchant composition is used. To etch the metal oxide, a conventional etchant composition contains sulfuric acid. The etchant composition containing sulfuric acid generates harmful substances and causes environmental problems. and, May damage other metal films including metals such as copper, aluminum, molybdenum, or titanium.

In order to solve the above problems, if the sulfuric acid component is removed from the etchant composition and the nitric acid content is increased, the amount of wastewater treated will increase due to the increase in the total amount of nitrogen.

In order to solve the above-mentioned problems, an object of the present invention is to provide an etchant composition that reduces the generation of substances harmful to the environment and prevents the damage of other metal layers by selectively etching the metal oxide layer.

Another object of the present invention is to provide a method for forming a transparent electrode using the etchant composition.

Another object of the present invention is to provide a method for manufacturing a display substrate using the etchant composition.

In order to achieve the object of the present invention, the etchant composition according to an embodiment includes: nitric acid, 3 wt% or more and less than 10 wt%; chloride, 0.01 wt% or more and 5 wt% or less; ammonia compound, 0.1 Above 5% by weight and below 5% by weight; cyclic amino compounds, above 0.1% by weight and below 5% by weight; the remaining weight% of water.

In one embodiment, the nitric acid may include nitric acid or nitrous acid.

In one embodiment, the chloride may include sodium chloride, potassium chloride or ammonia chloride.

In one embodiment, the ammonia compound may include ammonium sulfate or ammonium sulfide.

In one embodiment, the cyclic amino compound may include pyrrole, pyrazole, imidazole, triazole, tetrazole, pentazole, oxazole ( oxazole), isoxazole, thiazole or isothiazole.

In one embodiment, the cyclic amino compound may include benzotriazole, 5-aminotetrazole, 3-aminotetrazole, and 5-methyltetrazole.

According to the method for forming a transparent electrode according to an embodiment for achieving another object of the present invention, a transparent electrode layer including a metal oxide is formed on a substrate. A photoresist pattern is formed on the transparent electrode layer. And using the photoresist pattern as a mask to provide an etchant composition to a transparent electrode layer including the metal oxide to etch the transparent electrode layer, wherein the etchant composition includes: nitric acid 3% by weight or more and less than 10% by weight; chlorides, 0.01% by weight or more and 5% by weight or less; ammonia compounds, 0.1% by weight or more and 5% by weight or less; cyclic amino compounds, 0.1% by weight or more and 5% by weight Below; the remaining weight% of water.

In one embodiment, the transparent electrode may include indium zinc oxide or indium tin oxide.

In one embodiment, the nitric acid may include nitric acid or nitrous acid.

In one embodiment, the chloride may include sodium chloride, potassium chloride or ammonia chloride.

In one embodiment, the ammonia compound may include ammonium sulfate or ammonium sulfide.

In one embodiment, the cyclic amino compound may include pyrrole, pyrazole, imidazole, triazole, tetrazole, pentazole, oxazole ( oxazole), isoxazole, thiazole or isothiazole.

In one embodiment, the cyclic amino compound may include benzotriazole, 5-aminotetrazole, 3-aminotetrazole, and 5-methyltetrazole.

According to a method of manufacturing a display substrate according to an embodiment for realizing another object of the present invention, a thin film transistor is formed on a substrate, the thin film transistor including: a gate electrode; a semiconductor layer overlapping the gate electrode; a source An electrode is in contact with the semiconductor layer; a drain electrode is in contact with the semiconductor layer and separated from the source electrode. A protective film is formed to cover the thin film transistor. Patterning the protective film to expose the drain electrode. A metal oxide layer is formed on the protective film. The metal oxide layer is etched with an etchant composition to form a pixel electrode connected to the drain electrode. The etchant composition includes: nitric acid, 3 wt% or more and less than 10 wt%; chloride, 0.01 wt% or more and 5 wt% or less; ammonia compounds, 0.1 wt% or more and 5 wt% or less; cyclic amino compounds , Above 0.1% by weight and below 5% by weight; the remaining weight% is water.

In one embodiment, the transparent electrode may include indium zinc oxide or indium tin oxide.

In one embodiment, the nitric acid may include nitric acid or nitrous acid.

In one embodiment, the chloride may include sodium chloride, potassium chloride or ammonia chloride.

In one embodiment, the ammonia compound may include ammonium sulfate or ammonium sulfide.

In one embodiment, the cyclic amino compound may include pyrrole, pyrazole, imidazole, triazole, tetrazole, pentazole, oxazole ( oxazole), isoxazole, thiazole or isothiazole.

In one embodiment, the cyclic amino compound may include benzotriazole, 5-aminotetrazole, 3-aminotetrazole, and 5-methyltetrazole.

The etchant composition according to the embodiment of the present invention can selectively etch the metal oxide layer, thereby preventing the metal layer containing copper, titanium, molybdenum, or aluminum from being etched.

Moreover, since sulfuric acid is not contained in the etching solution, environmental pollution can be prevented by preventing the generation of harmful substances caused by sulfuric acid.

In order to have a better understanding of the above and other aspects of the present invention, the following specific examples are given below in conjunction with the accompanying drawings to make a detailed description as follows:

GL‧‧‧Gate line

GE‧‧‧Gate electrode

SE‧‧‧Source electrode

DE‧‧‧Drain electrode

AP‧‧‧Active Pattern

OC‧‧‧ohm contact layer

PE‧‧‧Pixel electrode

110‧‧‧ substrate

120‧‧‧Gate insulation

140‧‧‧ passivation layer

160‧‧‧Organic insulating layer

1 to 6 are cross-sectional views showing a method for manufacturing a display substrate.

In the following, the etchant composition according to the first embodiment of the present invention will be described first, and then the transparency of the etchant composition using the etchant composition will be described with reference to the drawings. A method for forming an electrode and a method for manufacturing a display substrate will be described in more detail.

Etchant composition

The etchant composition according to the first embodiment of the present invention includes: nitric acid, chloride, ammonia compound, cyclic amino compound, and water as the remaining components. The etchant composition can be used to selectively etch a metal oxide layer. Specifically, the etchant composition can be used for transparent conductive oxidation such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZNO), and the like. Etching of objects. The indium tin oxide or indium zinc oxide may have a crystalline structure or an amorphous structure. The etchant composition can prevent or minimize damage to a metal film containing copper, aluminum, molybdenum, or titanium. Hereinafter, each composition will be specifically described.

Nitric acid

The nitric acid contained in the etchant composition can etch the metal oxide layer. For example, nitric acid includes nitric acid (HNO ₃ ) and nitrous acid (HNO ₂ ).

If the content of nitric acid is less than 3% by weight relative to the total mass of the etchant composition, the etching rate of the etchant composition to the metal oxide layer is reduced, and the metal oxide layer is etched unevenly. The problem. If the metal oxide layer is etched unevenly, it may be considered as a spot. On the other hand, if the amount of nitric acid exceeds about 10% by weight, the etching rate becomes too fast, and adjustment of the etching technique becomes difficult. Moreover, as the total amount of nitrogen increases, the amount of wastewater treatment increases. Therefore, the content of nitric acid is preferably about 3% by weight or more and small. It is about 10% by weight, more preferably 5% by weight or more and about 8% by weight or less.

The etchant composition of the present invention preferably does not include phosphoric acid, hydrochloric acid, or sulfuric acid. If the etchant composition contains phosphoric acid, hydrochloric acid, or sulfuric acid, the pH value of the etchant will be lowered, and the metal layer such as copper, titanium, molybdenum, or aluminum may be damaged during the etching of the metal oxide layer.

chloride

The chloride contained in the etchant composition replaces inorganic acids such as phosphoric acid, hydrochloric acid, and sulfuric acid, and functions to improve the performance of etching the metal oxide layer.

If the content of the chloride is less than 0.1% by weight relative to the total weight of the etchant composition, the etching rate of the metal oxide layer is slowed due to the limited amount of nitric acid used. On the contrary, if the content of the chloride exceeds 5% by weight, the selective etching of the metal oxide layer becomes difficult, and the metal layer containing copper, titanium, molybdenum, or aluminum may be damaged. Therefore, the content of the chloride is preferably about 0.1% by weight or more and about 5% by weight or less, and more preferably about 2% by weight or more and about 3% by weight or less.

The chloride may be a compound containing a halogen ion. Specifically, sodium chloride, potassium chloride, ammonia chloride, and the like can be used, and sodium chloride can be preferably used.

Cyclic amino compounds

The cyclic amino compound in the etchant composition plays a role in preventing corrosion of a metal layer including a metal.

If the content of the cyclic amino compound is relative to the etchant If the total weight of the composition is less than about 0.01% by weight, selective etching of a transparent electrode including a metal oxide becomes difficult, and further, a metal layer including copper, aluminum, molybdenum, or titanium may be damaged. In addition, the reaction with metal oxides and chlorides becomes difficult, resulting in generation of residues after etching. In contrast, if the content of the cyclic amino compound exceeds about 1% by weight, etching of copper becomes difficult. Therefore, the content of the cyclic amino compound is preferably 0.01% by weight or more and about 1% by weight or less, and more preferably about 0.1% by weight or more and about 0.7% by weight or less.

The cyclic amino compound may be an azole compound having a five-membered heterocyclic ring having at least one non-carbon atom containing nitrogen in the ring. Specifically, a pyrrole-based compound, a pyrazole-based compound, an imidazole-based compound, a triazole-based compound, a tetrazol-based compound, and a pentazole-based compound can be used. , Oxazole-based compounds, isoxazole-based compounds, thiazole-based compounds, isothiazole-based compounds, etc., and one of them may be used alone or a plurality of them may be used in combination.

For example, the azole-based compound is preferably benzotriazole, 5-aminotetrazole, 3-aminotetrazole, or methyltetrazole such as 5-methyltetrazole. System, more preferably benzotriazole.

water

Water includes deionized water. For example, water used for semiconductor engineering may have a resistivity of about 18 MΩ / cm. Water in the place The etchant composition occupies the remainder except for the contents of nitric acid, chloride, ammonia compound and cyclic amino compound.

The etchant composition according to the embodiment of the present invention can selectively etch the metal oxide layer, so that the metal layer including copper, titanium, molybdenum, or aluminum can be prevented from being etched.

Moreover, since sulfuric acid is not contained in the etching solution, environmental pollution can be prevented by preventing the generation of harmful substances caused by sulfuric acid.

Forming method of transparent electrode and manufacturing method of display substrate

Hereinafter, a method for forming a transparent electrode and a method for manufacturing a display substrate according to embodiments of the present invention will be described in detail with reference to the drawings. The method of forming the transparent electrode will be described with reference to a step of forming a pixel electrode in the method of manufacturing a display substrate.

1 to 6 are cross-sectional views for explaining a method for manufacturing a display substrate according to an embodiment of the present invention.

The display substrate may be an array substrate for a display device. The transparent electrode according to an embodiment of the present invention may be used as a pixel electrode or a common electrode of a display device.

Referring to FIG. 1, a gate line GL and a gate electrode GE are formed on a substrate 110. Specifically, after a gate metal layer is formed on the substrate 100, the gate metal layer is patterned to form the gate line GL and the gate electrode GE. The substrate 100 may be a glass substrate, a quartz substrate, a silicon substrate, a plastic substrate, or the like.

The gate metal layer includes copper, silver, chromium, molybdenum, aluminum, titanium, manganese or Their alloys. The gate metal layer may have a single-layer structure or a multi-layer structure including a plurality of metal layers containing mutually different substances. For example, the gate metal layer may include a copper layer and a titanium layer formed on upper and / or lower portions of the copper layer.

Referring to FIG. 2, the gate insulating layer 120 is formed on the gate electrode GE. The gate insulating layer 120 covers the substrate 110 and the gate electrode GE. The gate insulating layer 120 may include an inorganic insulating substance. For example, the gate insulating layer may include silicon oxide (SiOx) and silicon nitride (SiNx). For example, the gate insulation layer 120 may include silicon oxide (SiOx) and have a thickness of 500 Å. Also, the gate insulating layer 120 may have a multilayer structure including substances different from each other.

Referring to FIG. 3, a semiconductor layer and a data metal layer are formed on the gate insulation layer 120 and patterned to form an active pattern AP and a data line including a source electrode SE and a drain electrode DE.

The data metal layer is etched by wet etching using an etchant. The etching solution does not substantially etch the active pattern AP.

The active pattern AP, the source electrode SE, and the drain electrode DE are formed on the gate insulating layer 120 in a region where the gate electrode GE is formed. The source electrode SE and the drain electrode DE are arranged separately from each other on the active pattern AP.

The active pattern AP overlaps the gate electrode GE, and partially overlaps the source electrode SE and the drain electrode DE, respectively. The active pattern AP is interposed between the gate electrode GE and the source electrode SE, and may be interposed between the gate electrode GE and the drain electrode DE.

The display substrate may include an ohmic contact layer OC formed on the active pattern AP. The active pattern AP may include a silicon semiconductor substance, such as amorphous silicon. The ohmic contact layer OC is interposed between the active pattern AP and the source electrode SE, and is interposed between the active pattern AP and the drain electrode DE. The ohmic contact layer OC may include amorphous silicon doped with n-type impurities at a high concentration.

The source electrode SE and the drain electrode DE may include copper (Cu), silver (Ag), chromium (Cr), molybdenum (Mo), aluminum (Al), titanium (Ti), manganese (Mn), or the like. The single-layer structure of the alloy or the multilayer structure of a plurality of metal layers containing different materials. For example, the source electrode SE and the drain electrode DE may include a titanium (Ti) layer formed on an upper part and / or a lower part of the copper (Cu) layer.

Referring to FIG. 4, a passivation layer 140 is formed on the source electrode SE and the source electrode DE. The passivation layer 140 may include silicon oxide (SiOx) and silicon nitride (SiNx).

An organic insulating layer 160 is formed on the passivation layer 140. The organic insulating layer 160 includes an organic substance. The organic insulating layer 160 can flatten the surface of the display substrate, and can be formed by spin coating the photoresist composition on the passivation layer 140. If the display substrate includes a color filter, the color filter may be formed instead of the organic insulating layer 160.

Referring to FIG. 5, a metal oxide layer is formed on the passivation layer 140. The metal oxide layer may include a transparent conductive substance. For example, it may include indium tin oxide (ITO) or indium zinc oxide (IZO).

Referring to FIG. 6, a pixel electrode PE is formed by etching the metal oxide layer. A photoresist pattern is formed on the metal oxide layer. Using the photoresist pattern as a mask, wet etching is performed using an etchant composition. The etchant composition includes: nitric acid, chloride, ammonia compound, cyclic amino compound, and other water. The etchant composition is substantially the same as the etchant composition according to the embodiment of the present invention, so detailed description is omitted.

The etchant composition can be provided by a spray method, a penetration method, or the like. The etchant composition may include nitric acid, chloride, ammonia compounds, cyclic amino compounds, and other water.

The pixel electrode PE may be electrically connected to the drain electrode DE through a contact hole, which is formed by patterning the passivation layer 140 and the organic insulating layer 160.

After the metal oxide layer is formed, or after the metal oxide layer is etched, the display substrate on which the pixel electrode PE is formed may be washed with a brush, water, or an organic solvent.

Although not shown, an alignment film for aligning liquid crystals may be formed on the pixel electrode PE. In other embodiments, the display substrate may further include a common electrode that forms an electric field with the pixel electrode PE.

The thin film transistor of the display substrate described in this embodiment has a bottom gate structure in which a gate electrode is disposed below an active pattern. However, in other embodiments, there may be a top gate structure in which gates are arranged on the active pattern.

Hereinafter, referring to the experimental results of specific examples and comparative examples, The effect of the etchant composition according to the embodiment of the present invention will be described.

According to an embodiment of the present invention, by selectively etching the metal oxide layer, the metal layer including copper, titanium, molybdenum, or aluminum can be prevented from being etched.

In addition, since the etching solution does not contain sulfuric acid, environmental pollution can be prevented by preventing the generation of harmful substances caused by sulfuric acid.

Hereinafter, the effects of the etchant composition according to the embodiment of the present invention will be described with reference to experimental results of specific examples and comparative examples.

Preparation of Etchant Composition

According to Table 1 below, an etchant composition up to 10 kg was prepared, including nitric acid (HNO ₃ ), sodium chloride (NaCl) as a chloride, and ammonium sulfate ((NH ₄ ) ₂ SO ₄ ) as an ammonia compound. ), Benzotriazole and other water as cyclic amino compounds.

Evaluation experiment of etching performance of etchant composition 1

The etchant compositions of Examples 1 to 6 and Comparative Examples 1 to 8 were sprayed onto samples of an indium zinc oxide film and a photoresist pattern including about 550 Å and an amorphous film including about 550 Å, respectively, laminated on a glass substrate. On a sample of a high-quality indium tin oxide (a-ITO) film and a photoresist pattern, the metal oxide layer was overetched by 90% based on the time required until the end of the etching. Then, the CD misalignment of the sample was measured using a scanning electron microscope photograph, and the results were collected in Table 2 below. Hereinafter, CD misalignment is defined as the distance between the end of the photoresist pattern and the metal oxide film.

A sample including an indium zinc oxide film and a photoresist pattern or an indium tin oxide film and a photoresist pattern of about 550Å laminated on a glass substrate was prepared. The etchant compositions of Examples 1 to 6 and Comparative Examples 1 to 8 were sprayed on the samples, and the copper layer was over-etched by 90% based on the time required to the end point (EPD) of the etching. The etching end point of the sample including the indium zinc oxide film and the photoresist pattern was 130 seconds, and the etching end point of the sample including the indium tin oxide film and the photoresist pattern was 280 seconds. The temperature of the etchant composition was 33 ° C.

Referring to Table 2, the measurement results were: the CD dislocation value of the indium zinc oxide films etched with Examples 1 to 6 not containing sulfuric acid was 0.24 μm, and the CD dislocation value of the indium tin oxide film was 0.1 μm.

The CD dislocation value of the indium zinc oxide film and the CD dislocation value of the indium tin oxide film etched in Comparative Example 4 containing 2.6% by weight of sodium chloride, 0.5% by weight of benzotriazole, and 1.0% by weight of ammonium sulfate. Measured to be 0 μm.

The CD dislocation value of the indium zinc oxide film etched with Comparative Example 5 containing 7.5% by weight of nitric acid, 0.5% by weight of benzotriazole, and 1.0% by weight of ammonium sulfate was 0.08 μm, and the CD of the indium tin oxide film was 0.08 μm. The misalignment value was measured as 0.02 μm.

Contains 7.5% by weight of nitric acid, 2.6% by weight of sodium chloride and 1.0 The CD dislocation value of the etched indium zinc oxide film of Comparative Example 6 by weight% ammonium sulfate was measured to be 0.29 μm, and the CD dislocation value of the indium tin oxide film was measured to be 0.14 μm.

The CD dislocation value of the indium zinc oxide film etched with Comparative Example 7 containing 7.5% by weight of nitric acid, 2.6% by weight of sodium chloride and 0.5% by weight of benzotriazole was measured to be 0.32 μm. The CD misalignment value was measured as 0.14 μm.

Therefore, based on the composition of the etchant composition of Comparative Examples 4 to 7, the same etching performance as that of the etchant composition of Examples 1 to 6 was not exhibited.

The CD dislocation value of the indium zinc oxide film etched with Comparative Example 8 containing 7 wt% nitric acid, 0.5 wt% benzotriazole, 5 wt% sulfuric acid, and 1 wt% ammonia sulfate was measured to be 0.24 μm, and indium The CD dislocation value of the tin oxide film was measured to be 0.1 μm.

Therefore, it can be confirmed that the etching performance of Examples 1 to 6 not containing sulfuric acid is the same as that of Comparative Example 8 containing sulfuric acid.

Evaluation experiment of etching performance of etchant composition 3

The etchant compositions of Examples 1 to 6 and Comparative Examples 1 to 8 were sprayed onto a metal layer including a titanium layer of about 200 Å and a copper layer of about 10,000 Å and a metal layer including two The metal layer of an aluminum layer of about 10,000 Å between the molybdenum layers was measured with a scanning electron microscope, and then compared with the metal layer before etching, and the results are summarized in Table 3 below. The metal layer was etched for 10 minutes and the temperature of the etchant composition was 33 ° C.

"○" in Table 3 indicates that all the metal layers are damaged, "△" indicates that the metal layer is partially damaged, and "X" indicates that the metal layer is not substantially damaged.

Referring to Table 3, the metal layer including copper etched using Comparative Example 6 or Comparative Example 7 has a greater degree of damage than the metal layer before etching, and in contrast, the metal layer including copper etched using Examples 1 to 6 not containing sulfuric acid The damage is smaller than the metal layer before etching. It can be confirmed that the damage degree of the metal layer including copper etched by using Examples 1 to 6 of the present invention is the same as the damage degree of the metal layer including copper etched by Comparative Example 8, wherein Comparative Example 8 contains 7% by weight of nitric acid 0.5% by weight of benzotriazole, 5% by weight of sulfuric acid and 1% by weight of ammonium sulfate.

Moreover, the aluminum-containing The degree of damage of the metal layer was greater than that of the metal layer before the etching, and in contrast, the degree of damage of the metal layer including aluminum etched using Examples 1 to 6 not containing sulfuric acid was less than that of the metal layer before the etching. It can be confirmed that the degree of damage of the metal layer including aluminum etched using Examples 1 to 6 of the present invention is the same as the degree of damage of the metal layer including aluminum etched with Comparative Example 8, wherein Comparative Example 8 contains 7% by weight of nitric acid 0.5% by weight of benzotriazole, 5% by weight of sulfuric acid and 1% by weight of ammonium sulfate.

Therefore, the etchant components of Examples 1 to 6 not containing sulfuric acid prevent the metal layer including copper, titanium, molybdenum, or aluminum from being damaged by selectively etching the metal oxide layer.

Moreover, since sulfuric acid is not included in the components in Examples 1 to 6, environmental pollution can be prevented by preventing the generation of harmful substances caused by sulfuric acid.

Above, although the description has been made with reference to the embodiments, it should be recognized that those skilled in the art can implement various modifications and variations to the present invention without departing from the scope and spirit of the present invention described in the scope of patent application. .

In summary, although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.

Claims (9)

An etchant composition for etching a transparent electrode layer including indium zinc oxide or indium tin oxide, the etchant composition includes: nitric acid, 3% by weight or more and less than 10% by weight; sodium chloride, 0.01% by weight % Or more and 5% by weight or less; ammonia compound, 0.1% or more and 5% by weight or less, the ammonia compound including at least one selected from the group consisting of ammonium sulfate and ammonium sulfide; cyclic amino compound, 0.1 weight The cyclic amino compound is selected from the group consisting of pyrrole, pyrazole, imidazole, triazole, tetrazole, pentazole, oxazole, isoxazole, thiazole, and isothiazole, and the content is not less than 5% by weight. At least one of; and the remaining weight% of water, wherein the etchant composition does not include hydrochloric acid, phosphoric acid, or sulfuric acid. The etchant composition according to item 1 of the scope of patent application, wherein the nitric acid includes at least one selected from the group consisting of nitric acid and nitrous acid. The etchant composition according to item 1 of the scope of patent application, wherein the cyclic amino compound includes a compound consisting of benzotriazole, 5-aminotetrazole, 3-aminotetrazole, and 5-methyltetrazole. At least one selected in the group. A method for forming a transparent electrode includes the steps of: forming a transparent electrode layer including indium zinc oxide or indium tin oxide on a substrate; forming a photoresist pattern on the transparent electrode layer; and applying the light A resist pattern is used as a mask to provide an etchant composition to the transparent electrode layer to etch the transparent electrode layer, wherein the etchant composition includes: nitric acid, 3% by weight or more and less than 10% by weight; Sodium chloride, 0.01% to 5% by weight; ammonia compounds, 0.1% to 5% by weight; cyclic amino compounds, 0.1% to 5% by weight; and the remaining weight% of water, of which The ammonia compound includes at least one selected from the group consisting of ammonium sulfate and ammonium sulfide, and the cyclic amino compound includes a compound selected from pyrrole, pyrazole, imidazole, triazole, tetrazole, pentaazole, oxazole, At least one selected from the group consisting of isoxazole, thiazole, and isothiazole, and the etchant composition does not include hydrochloric acid, phosphoric acid, or sulfuric acid. The method for forming a transparent electrode according to item 4 of the scope of patent application, wherein the nitric acid includes at least one selected from the group consisting of nitric acid and nitrous acid. The method for forming a transparent electrode according to item 4 of the scope of patent application, wherein the cyclic amino compound includes a compound consisting of benzotriazole, 5-aminotetrazole, 3-amino At least one selected from the group consisting of methyltetrazole and 5-methyltetrazole. A method for manufacturing a display substrate includes the following steps: forming a thin film transistor on the substrate, wherein the thin film transistor includes: a gate electrode; a semiconductor layer overlapping the gate electrode; a source electrode and the semiconductor Layer contact; a drain electrode in contact with the semiconductor layer and separated from the source electrode; forming a protective film covering the thin film transistor; and patterning the protective film to expose the drain electrode; Forming a metal oxide layer including indium zinc oxide or indium tin oxide on the protective film; and etching the metal oxide layer with an etchant composition to form a pixel electrode connected to the drain electrode Wherein, the etchant composition includes: nitric acid, 3 wt% or more and less than 10 wt%; sodium chloride, 0.01 wt% or more and 5 wt% or less; ammonia compounds, 0.1 wt% or more and 5 wt% or less; A cyclic amino compound, from 0.1% by weight to 5% by weight; and the remaining weight% of water, wherein the ammonia compound includes a compound selected from a group consisting of ammonium sulfate and ammonium sulfide to At least one, the cyclic amino compound includes at least one selected from the group consisting of pyrrole, pyrazole, imidazole, triazole, tetrazole, pentaazole, oxazole, isoxazole, thiazole, and isothiazole. The etchant composition does not include hydrochloric acid, phosphoric acid, or sulfuric acid. The method for manufacturing a display substrate according to item 7 of the scope of patent application, wherein the nitric acid includes at least one selected from the group consisting of nitric acid and nitrous acid. The method for manufacturing a display substrate according to item 7 of the scope of patent application, wherein the cyclic amino compound includes a compound consisting of benzotriazole, 5-aminotetrazole, 3-aminotetrazole, and 5-methyltetrazole. Select at least one from the group.