KR20120065019A - Manufacturing method of an array substrate for liquid crystal display - Google Patents

Abstract

PURPOSE: An array substrate manufacturing method for LCD is provided to increase step coverage by supplying etchant composition of a copper metal film and to indicate a low taper profile. CONSTITUTION: A gate line is formed on a substrate. A copper metal film is etched as the etchant composite. A gate insulating layer is formed on the substrate including the gate line. A semiconductor layer is formed on the gate insulating layer. Source and drain electrodes are formed on the semiconductor layer. A photoreaction material selectively remains on the copper metal film.

Description

MANUFACTURING METHOD OF AN ARRAY SUBSTRATE FOR LIQUID CRYSTAL DISPLAY}

The present invention relates to a method of manufacturing an array substrate for a liquid crystal display device, an etching liquid composition of a copper-based metal film, an etching method of a copper-based metal film using the etching liquid composition, and an array substrate for a liquid crystal labeling device manufactured using the etching liquid composition. .

During the manufacture of the liquid crystal display, the process of forming the metal wiring on the substrate is usually performed by a metal film forming process by sputtering or the like, a photoresist forming process in a selective region by photoresist coating, exposure and development, and an etching process. It consists of the steps, and the washing process before and after an individual unit process, etc. are included. The etching process refers to a process of leaving a metal film in a selective region using a photoresist as a mask, and typically, a dry etching using a plasma or the like and a wet etching using an etching liquid composition are used.

In the liquid crystal display device manufactured as described above, resistance of metal wiring has recently emerged as a major concern. In the thin film transistor-liquid crystal display (TFT-LCD), solving the RC signal delay problem is a key factor in increasing the panel size and realizing high resolution, since resistance is a major factor causing RC signal delay. Therefore, in order to realize the reduction of RC signal delay, which is essential for the large-sized TFT-LCD, it is essential to develop a material of low resistance.

Chromium (Cr, resistivity: 12.7 × 10 ^-8 Ωm), molybdenum (Mo, resistivity: 5 x 10 ^-8 Ωm), aluminum (Al, resistivity: 2.65 × 10 ^-8 Ωm) and alloys thereof, which have been mainly used in the past Because of the large silver resistance, it is difficult to use as a gate and data wiring used in a large TFT LCD. Accordingly, attention has been paid to copper-based metal films such as copper films and copper molybdenum films and etching liquid compositions thereof.

However, since the copper-based etching liquid compositions known to date do not meet the performance required by the user, research and development for improving performance are required. In particular, the conventional copper-based etchant compositions have a taper level at the time of etching 60 to 70 degrees, there is a problem that the reliability of the device is lowered due to poor step coverage in a particular device.

The present invention provides a copper tape with a low taper profile of 40 to 45 degrees to form a profile having excellent etching uniformity and linearity, to improve step coverage leading to a subsequent process in a specific device, and leaving no residue of the metal film. It is an object to provide an etching solution composition of a metal film.

In addition, an object of the present invention is to provide an etching liquid composition of a copper-based metal film capable of collective etching of a gate electrode, a gate wiring, a source / drain electrode, and a data wiring.

In addition, an object of the present invention is to provide an etching method of a copper-based metal film and a method of manufacturing an array substrate for a liquid crystal display device using the etching liquid composition.

In order to achieve the above object, the present invention is based on the total weight of the composition, A) 5 to 25% by weight of hydrogen peroxide (H ₂ O ₂ ), B) 0.01 to 1.0% by weight of fluorine-containing compound, C) 0.1 to 5% by weight of azole compound %, D) 0.1 to 10.0% by weight of at least one compound selected from phosphonic acid derivatives and salts thereof, E) 0.1 to 1.0% by weight of nitrate compounds and F) remaining amount of water. .

In addition, the present invention comprises the steps of (I) forming a copper-based metal film on the substrate; II) selectively leaving a photoreactive material on the copper-based metal film; And iii) etching the copper-based metal film using the etchant composition of the present invention.

In addition, the present invention comprises the steps of a) forming a gate wiring on the substrate; b) forming a gate insulating layer on the substrate including the gate wiring; 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.

Step a) includes forming a copper-based metal film on the substrate, and etching the copper-based metal film with the etchant composition of the present invention to form a gate wiring, wherein step d) is a copper-based metal on the semiconductor layer Forming a film and etching the copper-based metal film with the etchant composition of the present invention to form a source and a drain electrode provides a method of manufacturing an array substrate for a liquid crystal display device.

In addition, the present invention provides an array substrate for a liquid crystal display device including at least one of a gate wiring and a source / drain electrode etched using the etchant composition of the present invention.

When etching the copper-based metal film, the etchant composition of the present invention has excellent etching uniformity and linearity, implements a low taper profile, and does not generate residue, thereby preventing electrical shorts, poor wiring, and reduced luminance. free.

In addition, the etchant composition of the present invention can etch the gate electrode, the gate wiring, the source / drain and the data wiring in a batch when manufacturing the array substrate for the liquid crystal display device, thereby simplifying the etching process and maximizing the process yield.

Therefore, the etchant composition of the present invention can be very useful for manufacturing an array substrate for a liquid crystal display device in which a large screen and a high luminance circuit are implemented.

1 is a scanning electron micrograph of the etching cross-section after etching the Cu / Mo-Ti double layer using the etchant composition of Comparative Example 1 of the present invention,
2 is a scanning electron micrograph of the etching cross section after etching the Cu / Mo-Ti double layer using the etchant composition of Example 2 of the present invention.

Hereinafter, the present invention will be described in detail.

The present invention provides a composition comprising: A) 5 to 25% by weight of hydrogen peroxide (H ₂ O ₂ ), B) 0.01 to 1.0% by weight of fluorine-containing compounds, C) 0.1 to 5% by weight of azole compounds, D) phosphonic acid derivatives and salts thereof It relates to an etching liquid composition of a copper-based metal film comprising 0.1 to 10.0% by weight of at least one selected compound, 0.1 to 1.0% by weight of E) nitrate compound and F) remaining water.

In the present invention, the copper-based metal film includes copper as a constituent of the film, and is a concept including a multilayer film such as a single film and a double film. For example, a copper molybdenum film, a copper molybdenum alloy film, etc. are contained as a single film | membrane of copper or a copper alloy, and a multilayer film.

The copper molybdenum film means to include a molybdenum layer and a copper layer formed on the molybdenum layer, and the copper molybdenum alloy film means to include a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer.

In addition, the molybdenum alloy layer is at least one selected from the group consisting of, for example, titanium (Ti), tantalum (Ta), chromium (Cr), nickel (Ni), neodymium (Nd), indium (In) and the like. It means an alloy of molybdenum.

A) hydrogen peroxide (H ₂ O ₂ ) included in the etchant composition of the present invention is the main component for etching the copper-based metal film, the content is 5 to 25% by weight relative to the total weight of the composition. When the content of hydrogen peroxide is less than 5% by weight, the copper-based metal is not etched or the etching rate is very slow, and when it exceeds 25% by weight, the process speed is difficult because the etching rate is generally increased.

B) fluorine-containing compound included in the etchant composition of the present invention means a compound capable of dissociating in water to give fluorine ions. The B) fluorine-containing compound serves to remove residues inevitably generated in a solution for simultaneously etching a copper film and a molybdenum film. The content of the B) fluorine-containing compound is 0.01 to 1.0% by weight based on the total weight of the composition. When the content of the B) fluorine-containing compound is less than 0.01% by weight, an etching residue may occur, and when the content of the fluorine-containing compound is greater than 1.0% by weight, the etching rate of the glass substrate may be greatly increased.

The B) fluorine-containing compound is not particularly limited as long as it can be dissociated into fluorine ions or polyatomic fluoride ions in a solution as a material used in this field, and ammonium fluoride (NH ₄ F) and sodium fluoride (sodium fluoride) selected from the group consisting of fluoride (NaF), potassium fluoride (KF), ammonium bifluoride (NH ₄ FHF), sodium bifluoride (NaFHF), and potassium bifluoride (KFHF) It is preferable that it is 1 or more types.

C) azole compound included in the etchant composition of the present invention controls the etching rate of the copper-based metal and serves to increase the process margin by reducing the CD loss of the pattern.

The content of the C) azole compound is 0.1 to 5% by weight based on the total weight of the composition. When the content of the C) azole-based compound is less than 0.1% by weight, the etching rate may be increased, so that cisidose is generated too much. When the content of the azole compound is greater than 5% by weight, the etching rate of copper is lowered and the etching of molybdenum or molybdenum alloy is performed. Because of the higher speed, molybdenum or molybdenum alloys may be overetched, resulting in undercuts.

The C) azole compound is, for example, aminotetrazole, benzotriazole, tolytriazole, pyrazole, pyrrole, imidazole, 2-methyl di Midazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4-ethylimidazole, 4-propylimidazole, and the like. One kind alone or two or more kinds may be used together.

The at least one compound selected from D) phosphonic acid derivatives and salts thereof included in the etchant composition of the present invention decomposes hydrogen peroxide by chelating copper ions dissolved in the etchant when the copper film is etched to inhibit the activity of the copper ions. Suppress the reaction. When the activity of copper ions is lowered in this way, the process can be stably performed while using the etching solution.

The content of at least one compound selected from D) phosphonic acid derivatives and salts thereof is 0.1 to 10.0% by weight, based on the total weight of the composition. When the content of at least one compound selected from the D) phosphonic acid derivatives and salts thereof is less than 0.1% by weight, etching uniformity is lowered and decomposition of hydrogen peroxide is accelerated, and when it exceeds 10.0% by weight, the etching rate is increased. Is too fast.

In at least one compound selected from the above phosphonic acid derivatives and salts thereof, representative examples of phosphonic acid derivatives include 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP: 1-hydroxyethylidene-1,1- diphosphonic acid), and representative examples of the phosphonic acid derivative salts include sodium or potassium salts of 1-hydroxyethylidene-1,1-diphosphonic acid.

E) nitrate compound included in the etchant composition of the present invention serves to lower the taper during etching. In certain devices, step coverage can be improved by lowering the taper of the copper film, thereby helping drive the device.

The content of the E) nitrate compound is 0.1 to 1.0% by weight based on the total weight of the composition. When the content of the nitrate compound is less than 0.1% by weight, the ability to lower the taper is lowered, and when the content of the nitrate compound is greater than 1.0% by weight, etching of the Cu and Mo-Ti thin films becomes too fast, making process control difficult.

Examples of the nitrate compound E include ammonium nitrate ((NH ₄ ) NO ₃ ), calcium nitrate (Ca (NO ₃ ) ₂ ), sodium nitrate (NaNO ₃ ), potassium nitrate (KNO ₃ ), magnesium nitrate (Mg ( NO ₃ ) ₂ ), aluminum nitrate (Al (NO ₃ ) ₃ ), and the like, and these may be used alone or in combination of two or more.

F) residual amount of water contained in the etchant composition of the present invention is not particularly limited, but deionized water is preferred. More preferably, deionized water having a specific resistance value of water (that is, the degree of removal of ions in water) of 18 kW / cm or more is preferably used.

The etchant composition of the present invention may further include a surfactant. The surfactant serves to decrease the surface tension to increase the uniformity of the etching. The surfactant is not particularly limited as long as it can withstand the etching liquid composition of the present invention and is compatible, but is not limited to anionic surfactants, cationic surfactants, zwitterionic surfactants, nonionic surfactants, and polyalcohol-type surfactants. It is preferably one or two or more selected from the group consisting of.

In addition to the above components, a conventional additive may be further added, and examples of the additive include a metal ion blocking agent, a corrosion inhibitor, and the like.

At least one compound selected from A) hydrogen peroxide (H ₂ O ₂ ), B) fluorine-containing compounds, C) azole compounds, D) phosphonic acid derivatives and salts thereof, E) nitrate compounds and F) An etchant containing the residual amount of water can be prepared by a conventionally known method, and preferably has a purity for a semiconductor process.

The etchant composition of the present invention may collectively etch the gate electrode, the gate wiring, the source / drain electrode, and the data wiring of the liquid crystal display device made of a copper-based metal.

Further, according to the present invention,

I) forming a copper-based metal film on the substrate;

II) selectively leaving a photoreactive material on the copper-based metal film; And

III) an etching method of a copper-based metal film comprising etching the copper-based metal film using the etchant composition of the present invention.

In the etching method of the present invention, the photoreactive material is preferably a conventional photoresist material, and may be selectively left by conventional exposure and development processes.

Further, according to the present invention,

a) forming a gate wiring on the substrate;

b) forming a gate insulating layer on the substrate including the gate wiring;

c) forming a semiconductor layer on the gate insulating layer;

d) forming source and drain electrodes on the semiconductor layer; And

e) a method of manufacturing an array substrate for a liquid crystal display device comprising forming a pixel electrode connected to the drain electrode;

Step a) includes forming a copper-based metal film on the substrate and etching the copper-based metal film with the etchant composition of the present invention to form a gate wiring,

The step d) includes forming a copper-based metal film on the semiconductor layer and etching the copper-based metal film with the etchant composition of the present invention to form source and drain electrodes. It relates to a manufacturing method.

The array substrate for a liquid crystal display device may be a thin film transistor (TFT) array substrate.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the Examples are provided to illustrate the present invention, but the present invention is not limited thereto.

Experimental Example Copper Metal film Etchant  Preparation of the composition

The etching liquid compositions of Examples 1 to 4 and Comparative Examples 1 and 2 were prepared according to the compositions shown in Table 1 below.

H ₂ O ₂ Ammonium Fluoride Aminotetrazole HEDP nitrate Deionized water Example 1 10 0.05 0.5 0.5 0.5 Balance Example 2 15 0.1 0.6 1.0 1.0 Balance Example 3 5 0.4 1.0 5.0 0.5 Balance Example 4 25 0.8 4.0 9.0 1.0 Balance Comparative Example 1 10 0.05 0.5 0.5 - Balance Comparative Example 2 15 0.1 0.6 1.0 - Balance

* HEDP: 1-hydroxyethylidene-1,1-diphosphonic acid

Test Example : Etchant  Characterization of the Composition

An etching process of the copper-based metal film (Cu single layer and Cu / Mo-Ti double layer) was performed using the etching solution compositions of Examples 1 to 4 and Comparative Examples 1 and 2. During the etching process, the temperature of the etchant composition is about 30 ° C., but the proper temperature may be changed as necessary by other process conditions and other factors. The etching time may vary depending on the etching temperature, but usually proceeds about 30 to 180 seconds. The profile of the copper-based metal film etched in the etching process was examined using a cross-sectional SEM (Model S-4700, manufactured by Hitachi), and the results are shown in Table 2 below.

　
　
　 Etching Speed (Å / sec) Taper Angle (˚) Cu monolayer Cu / Mo-Ti Double Layer Cu monolayer Cu / Mo-Ti
Double membrane Cu Mo-Ti Example 1 50-70 50-70 6-9 43 42 Example 2 70-100 70-100 7-10 42 40 Example 3 40-60 40-60 6 ~ 8 42 40 Example 4 70-90 70-90 8 ~ 11 41 42 Comparative Example 1 40-60 40-60 4 ~ 7 67 62 Comparative Example 2 60-90 60-90 5 ~ 8 63 61

From the results of Table 2, the etching rates of Examples 1 to 4 and Comparative Examples 1 and 2 were found to be appropriate. In addition, as can be seen in FIGS. 1 and 2, in the case of the copper-based metal film etched with the etchant composition according to Comparative Example 1, the taper was about 62 to 67 degrees, but the copper film-based metal film was etched with the etchant composition according to Example 2 In one case, the taper was about 40 to 42 degrees lower than about 25 degrees.

Claims (10)

a) forming a gate wiring on the substrate;
b) forming a gate insulating layer on the substrate including the gate wiring;
c) forming a semiconductor layer on the gate insulating layer;
d) forming source and drain electrodes on the semiconductor layer; And
e) a method of manufacturing an array substrate for a liquid crystal display device comprising forming a pixel electrode connected to the drain electrode;
The step a) includes forming a copper-based metal film on the substrate and etching the copper-based metal film with an etchant composition to form a gate wiring;
Step d) includes forming a copper-based metal film on the semiconductor layer and etching the copper-based metal film with an etchant composition to form source and drain electrodes.
The etching liquid composition, A) 5 to 25% by weight of hydrogen peroxide (H ₂ O ₂ ), B) 0.01 to 1.0% by weight of fluorine-containing compound, C) 0.1 to 5% by weight of azole compound, D) Force A method for producing an array substrate for a liquid crystal display device, comprising 0.1 to 10.0% by weight of at least one compound selected from phononic acid derivatives and salts thereof, 0.1 to 1.0% by weight of E) nitrate compounds and F) residual water. The method of claim 1, wherein the array substrate for a liquid crystal display device is a thin film transistor (TFT) array substrate. Regarding the total weight of the composition,
A) 5 to 25 weight percent hydrogen peroxide (H ₂ O ₂ );
B) 0.01 to 1.0 wt% fluorine-containing compound;
C) 0.1 to 5% by weight of an azole compound;
D) 0.1 to 10.0% by weight of at least one compound selected from phosphonic acid derivatives and salts thereof;
E) 0.1 to 1.0% by weight of nitrate compound and
F) An etchant composition of a copper metal film comprising a residual amount of water. The etchant composition according to claim 3, wherein the B) fluorine-containing compound is at least one selected from the group consisting of NH ₄ FHF, KFHF, NaFHF, NH ₄ F, KF, and NaF. The method according to claim 3, wherein the C) azole compound is aminotetrazole, benzotriazole, tolytriazole, pyrazole, pyrrole, imidazole, 2- Methylimidazole, 2-ethylimidazole, 2-propylimidazole, 2-aminoimidazole, 4-methylimidazole, 4-ethylimidazole and 4-propylimidazole. Etching liquid composition of a copper-based metal film, characterized in that at least one. The method of claim 3, wherein the D) at least one compound selected from phosphonic acid derivatives and salts thereof is 1-hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-1,1- Etching liquid composition of a copper-based metal film, characterized in that at least one selected from the group consisting of sodium salt of diphosphonic acid and potassium salt of 1-hydroxyethylidene-1,1-diphosphonic acid. The method of claim 3, wherein the E) nitrate compound is ammonium nitrate ((NH ₄ ) NO ₃ ), calcium nitrate (Ca (NO ₃ ) ₂ ), sodium nitrate (NaNO ₃ ), potassium nitrate (KNO ₃ ), magnesium nitrate ( Mg (NO ₃ ) ₂ ) and aluminum nitrate (Al (NO ₃ ) ₃ ) The etching liquid composition of the copper-based metal film, characterized in that at least one member selected from the group consisting of. The method of claim 3, wherein the copper-based metal film is a copper molybdenum film or a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer including a single film of copper or a copper alloy, a molybdenum layer and a copper layer formed on the molybdenum layer It is a copper molybdenum alloy film containing an etching liquid composition of the copper-based metal film. I) forming a copper-based metal film on the substrate;
II) selectively leaving a photoreactive material on the copper-based metal film; And
(III) etching the copper-based metal film using the etching solution composition of claim 3. An array substrate for a liquid crystal display device comprising at least one of a gate electrode, a gate wiring, a source and a drain electrode, and a data wiring etched using the etchant composition of claim 3.

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