WO2014098392A1 - Metal-film etching-solution composition and etching method using same - Google Patents

Abstract

Provided are: an etching-solution composition whereby it is possible to simultaneously etch a double film of a copper film and an indium tin oxide film or a double film of a copper film and a metal film; and an etching method using same. The etching-solution composition comprises between 5 and 20 wt.% of hydrogen peroxide, between 0.1 and 5 wt.% of a sulphonic acid compound, between 0.1 and 2 wt.% of a carbonyl based organic acid compound, between 0.1 and 0.4 wt.% of a fluorine compound, between 0.01 and 3 wt.% of an azole based compound, and a remainder of water.

Description

Metal film etching solution composition and etching method using the same

The present invention relates to a metal film etchant composition, and more particularly, to an etching solution composition and an etching method using the same, which can simultaneously etch a double film of a copper film and an indium tin oxide film, a copper film and a metal film.

In recent years, as the number of pixels in which pixel electrodes are formed increases with the high quality, high image quality, and large area of a display panel, such as a liquid crystal display (LCD), it is necessary to improve the response speed of the display panel. To this end, an array substrate process for applying a copper metal wiring, which is used as a conventional low resistance wiring, to a gate and a source / drain electrode, has been developed and used. have. In such an array substrate process, there is an advantage that the movement speed of the electrons can be adjusted according to the thickness of the copper metal layer and the lower barrier layer (Ti, Mo, Mo alloy, etc.). In addition, when a transparent electrode such as an indium tin oxide layer (ITO) is formed as a barrier film under a copper metal film in a gate electrode or a wiring, the response speed in a display panel such as an LCD can be improved. There is an advantage.

However, when forming a double layer of a copper film and an indium tin oxide film (Cu / ITO) as electrodes or wirings of a display panel, since the copper film and the indium tin oxide film are simultaneously etched simultaneously, it is difficult to form electrodes or wires. The copper film and the indium tin oxide film have to be etched in separate processes (secondary etching), and for this purpose, a 5-mask process has to be performed. In addition, as an etching liquid composition for etching the copper film or the indium tin oxide film, an oxidant solution mainly containing hydrogen peroxide, an inorganic acid, an organic acid, or the like is mainly used. However, such a conventional etching liquid composition has no particular problem when etching a single film of a copper film or an indium tin oxide film, but in general, since the etching rate of the indium tin oxide film is faster than that of the copper film, the copper film and the indium tin oxide film In etching a double layer, there is a disadvantage in that a tail, an etching profile defect, a taper angle defect, and the like of the indium tin oxide film, which is a barrier film, are caused. In addition, the conventional etching liquid composition is insufficient in stability, and may generate precipitates such as a residue, a residual layer, etc. over time of use.

SUMMARY OF THE INVENTION An object of the present invention is to provide an etching liquid composition capable of simultaneously etching a double film of a metal film, particularly a copper film and an indium tin oxide film, or a double film of a copper film and a metal film, and an etching method using the same.

Another object of the present invention is to provide an etching liquid composition having an excellent etching profile such as a taper angle and an etching method using the same even when etching a double layer of a copper film and an indium tin oxide film.

Still another object of the present invention is to provide an etching solution composition and an etching method using the same, wherein the etching rate is fast, and many substrates can be processed in a short time, and unstable hydrogen peroxide is stabilized with an organic acid, thereby improving stability.

In order to achieve the above object, the present invention, 5 to 20% by weight of hydrogen peroxide; 0.1-5% by weight of sulfonic acid compound; 0.1 to 2 wt% carbonyl organic acid compound; 0.1 to 0.4% by weight of fluorine compound; 0.01-3% by weight of an azole compound; And it provides an etchant composition comprising the remaining water.

In addition, the present invention, forming a photoresist pattern of a predetermined shape on a substrate on which a metal film is formed; And etching the metal film from the substrate by using the photoresist pattern as a mask and contacting the etchant composition to provide an etching method.

Instead of separately etching the upper copper layer and the lower transparent electrode layer (ITO) or the lower metal layer (secondary etching), the etchant composition according to the present invention may simultaneously etch simultaneously, and has an excellent etching profile such as a taper angle. In addition to the fast etching speed, the stability is excellent.

1 is an electron scanning micrograph of a copper film and an indium tin oxide double film etched using the compositions of Examples 1 to 5 of the present invention.

2 is an electron scanning micrograph of a copper film and an indium tin oxide double film etched using the compositions of Comparative Examples 1 to 5 of the present invention.

Hereinafter, the present invention will be described in detail.

The etchant composition according to the present invention is for simultaneously etching a double film including a copper film, 5 to 20% by weight of hydrogen peroxide (H ₂ O ₂ ), 0.1 to 5% by weight of sulfonic acid compound , 0.1 to 2% by weight of carbo It includes a nile organic acid compound, 0.1 to 0.4% by weight of fluoride (Fluoride), 0.01 to 3% by weight of the azole compound and the remaining water.

Hydrogen peroxide (H ₂ O ₂ ) used in the etchant composition of the present invention is an oxidant for oxidizing and etching the copper film through the same process as in Scheme 1 below.

Scheme 1

Cu + H ₂ O ₂ → CuO + H ₂ O

The content of the hydrogen peroxide (H ₂ O ₂ ) is 5 to 20% by weight, preferably 5 to 15% by weight, more preferably 5 to 10% by weight based on the total etching liquid composition. If the content of hydrogen peroxide (H ₂ O ₂ ) is too small, there is a fear that the copper film is insufficiently etched, if too large, the etching rate of the copper film is excessively fast, the copper film in the double film etching of the copper film / indium tin oxide film There is a risk of over-etching.

The sulfonic acid compound is an auxiliary oxidant of the copper film and the indium tin oxide film (transparent electrode film). The sulfonic acid compound is a compound that generates sulfonate ions (SO ₃ ⁻ ) in an aqueous solution, and includes benzenesulfonic acid (C ₆ H ₅ SO ₃ H) and toluenesulfonic acid. p-CH ₃ C ₆ H ₄ SO ₃ H), cyclic or chain hydrocarbon sulfonic acid compound having 1 to 10 carbon atoms, such as methanesulfonic acid (CH ₃ SO ₃ H), aminosulfonic acid (amino ₂₎ Inorganic sulfonic acid compounds such as SO ₃ H), salts thereof (for example, ammonium salts), mixtures thereof, and the like, and preferably methanesulfonic acid (CH ₃ SO ₃ H) can be used. The content of the sulfonic acid compound is 0.1 to 5% by weight, preferably 0.2 to 3% by weight, more preferably 0.5 to 2% by weight based on the total composition. When the content of the sulfonic acid compound is less than the above range, the etching of the copper film may be insufficient. When the sulfonic acid compound is above the above range, the etching rate of the copper film may be too high, and process control may be difficult.

The carbonyl-based organic acid compound is ligand-bonded with primary copper ions generated by etching of the copper film, and serves as a chelating agent to mitigate the decrease in the oxidation power of hydrogen peroxide by the copper ions over time. The carbonyl organic acid compound may be selected from the group consisting of malonic acid, succinic acid, formic acid, lactic acid, C ₃ H ₆ O ₃ , and mixtures thereof. Compounds can be used, preferably lactic acid. The content of the carbonyl organic acid compound is 0.1 to 2% by weight, preferably 0.1 to 1% by weight, more preferably 0.1 to 0.5% by weight based on the total composition. When the content of the carbonyl organic acid compound is less than the above range, there is a concern that the stabilization of the copper ions may be insufficient. When the content of the carbonyl-based organic acid compound exceeds the above range, there is no additional help to the stabilization of the copper ions. There is a concern.

The fluoride compound controls the etching rate of the indium tin oxide (ITO) transparent electrode, which is a barrier film of the copper film, and serves to form a taper angle in the double film or multiple films. As the fluorine compound, various compounds for generating fluoride ions (F ⁻ ) in an aqueous solution may be used. Preferably, KF, NaF, NH ₄ F (ammonium fluoride), NH ₄ HF ₂ (ammonium bifluoride) ), H ₂ SiF ₆ , HBF ₄ , H ₂ TiF ₆ , H ₂ ZrF ₆ , mixtures thereof, and the like, and more preferably NaF (sodium fluoride). The content of the fluorine compound is 0.1 to 0.4% by weight, preferably 0.1 to 0.2% by weight based on the total composition. If the content of the fluorine compound is less than the above range, the etching rate of the barrier film may be lowered and the taper angle may be poor. If the content of the above fluorine compound exceeds the above range, the copper film or the glass film below the transparent positive electrode film is etched by the fluorine ion. The barrier film may be overetched.

The azole compound used in the etchant composition of the present invention suppresses the etching of the copper film, thereby controlling the etching rate of the copper film and the indium tin oxide film (ITO), as well as the cut dimension loss of the copper metal wiring. By reducing CD loss, metal wiring can be used as gate and data wiring. As the azole compound, a 5-membered heterocyclic compound containing a nitrogen atom and at least one non-carbon atom in the ring can be used. For example, benzotriazole, aminotetrazole, CH ₃ N ₅ ), imidazole, pyrazole, mixtures thereof, and the like, preferably aminotetrazole can be used. The content of the azole compound is 0.01 to 3% by weight, preferably 0.05 to 1% by weight, more preferably 0.1 to 0.2% by weight based on the total composition. If the content of the azole compound is less than the above range, there is a fear that the copper film is excessively etched, if it exceeds the above range, there is no particular benefit, it is economically undesirable.

In the etchant composition of the present invention, the remaining components are water (including an aqueous medium having the same function as "water" in the present specification), preferably deionized water (DI), distilled water and the like. The etchant composition according to the present invention may further include conventional additives, such as a pH adjuster and a corrosion inhibitor, as necessary, within the limits of achieving the object and effect of the invention. The etchant composition according to the present invention may be prepared by any known method. For example, a sulfonic acid compound , a carbonyl organic acid compound, a fluorine compound, an azole compound, and the like are added at a concentration required for an aqueous medium such as deionized water and distilled water, and then an aqueous solution of hydrogen peroxide (H ₂ O ₂ ) is added to the aqueous solution. The composition of the present invention can be prepared by adding to the medium at a desired concentration.

The etching liquid composition according to the present invention is a metal film, preferably (i) a double film of a copper film / indium tin oxide film formed by laminating a copper film and an indium tin oxide film, and (ii) a copper film formed by laminating a copper film and a metal film. It is useful for batch etching of double film of metal film. For example, in manufacturing a liquid crystal display (LCD) panel or the like, a pixel electrode or a thin film transistor (TFT) electrode made of a double film of a copper film / indium tin oxide film is formed, or a pixel electrode and copper made of an indium tin oxide film are formed. In the case where the thin film transistor electrode wiring made of a film is superimposed, the double film can be effectively etched using the composition of the present invention. Typically, a copper film / indium tin oxide double film is used as a gate electrode, and a copper / metal film, in particular, a copper / metal alloy film, for example, a copper / molybdenum-titanium (MoTi) alloy film, is used as a source or drain electrode. Used. Here, the copper film may be a single component copper film made of pure copper (Cu), an alloy containing copper (Cu) and other metals such as molybdenum (Mo), titanium (Ti), or, in the case of an alloy, Although the ratio of copper is not specifically limited, It is 10 weight% or more, Preferably it is 30 weight% or more, More preferably, it is 50 weight% or more. Further, the indium tin oxide film includes indium oxide and tin oxide (in this case, the content of indium oxide relative to the tin oxide component is usually 20 mol% or more, preferably 50 mol% As mentioned above, Al, Ni, Cu, Ta, Hf, Ti, etc. may be doped as needed. As the method for etching a metal film (preferably a double film of a copper film and an indium tin oxide film / metal film) using the etching liquid composition of the present invention, a conventional metal film-etching liquid composition contacting method can be used. For example, a photoresist pattern having a predetermined shape may be formed on a substrate on which a double layer is formed, and the photoresist pattern may be used as a mask, and the etching solution composition of the present invention may be contacted to simultaneously remove and remove the double layer from the substrate.

Using the etchant composition according to the present invention, in order to form a conventional gate wiring, the second etching of the double layer of the copper film / indium tin oxide film using a 5 mask (mask), using a 4 mask (mask) In this case, the double layer of the copper film / indium tin oxide film can be etched in a batch, thereby simplifying the process and improving the production yield. In addition, when the etchant composition according to the present invention is used, source / drain (S / D) wiring may be simultaneously etched, and thus, the gate and source / drain electrodes may be substantially etched collectively. Further, according to the present invention, in the formation of the wiring of the copper metal film which requires the batch etching of the double film or the multilayer film, a fast etching process and excellent tapered etching and profile can be obtained.

Hereinafter, the present invention will be described in more detail with reference to specific examples and comparative examples. The following examples are intended to illustrate the present invention in more detail, and the present invention is not limited by the following examples.

[Examples 1-5, Comparative Examples 1-5] Preparation and Evaluation of Etching Liquid Composition

In order to evaluate the etching performance of the etchant composition, hydrogen peroxide (H ₂ O ₂ ), methanesulfonic acid (MSA, CH ₃ SO ₃ H), lactic acid (C ₃₎ Preparation of an etchant composition (Examples 1 to 5, Comparative Examples 1 to 5) comprising H ₆ O ₃ ), sodium fluoride (NaF), aminotetrazole (ATZ, CH ₃ N ₅ ), and deionized water It was.

Table 1 Hydrogen Peroxide (H ₂ O ₂ ) Methanesulfonic acid (CH ₃ SO ₃ H) Lactate (C ₃ H ₆ O ₃ ) Sodium Fluoride (NaF) Aminotetrazole (CH ₃ N ₅ ) Example 1 5.0 0.5 0.1 0.1 0.1 Example 2 6.0 1.0 0.1 0.1 0.1 Example 3 7.0 1.0 0.1 0.2 0.1 Example 4 8.0 1.5 0.5 0.2 0.15 Example 5 10.0 2.0 0.5 0.2 0.15 Comparative Example 1 10.0 2.0 3.0 0.2 0.15 Comparative Example 2 10.0 2.0 0.5 0.5 0.2 Comparative Example 3 10.0 3.0 1.0 0.2 5.0 Comparative Example 4 25.0 4.0 1.0 0.3 0.3 Comparative Example 5 10.0 10.0 1.0 0.4 0.3

Etch test of copper film / indium tin oxide film and copper film / metal film

(i) a double film consisting of a copper film (Cu, top film) / indium tin oxide film (ITO, bottom film) and (ii) a copper film (Cu, top film) / molybdenum-titanium alloy film (Mo / Ti, bottom film) ) Was etched with the etchant compositions of Examples 1-5 and Comparative Examples 1-5, but was 100% overetched on a time basis from EPD (End Point Detection) of the lower layer. Side cross-sectional images of the etched bilayers were taken with an electron scanning microscope, and are shown in FIGS. 1 (Examples 1 to 5) and 2 (Comparative Examples 1 to 5), from which the etching characteristics (etch rate, CD skew (Critical) dimension skew, which represents the distance between the photoresist film end and the copper film end, the steps are small, and in order for the taper etching to be performed evenly, this distance must be in an appropriate range), and the taper angle (the side of the etched metal film) Inclination, about 40-45 ° is an appropriate value)), and the results are shown in Tables 2 and 3, respectively. In Tables 2 and 3, when the etching rate is 30 to 50 seconds (sec), very good (◎), 50 to 60 seconds is excellent (○), when exceeding 60 seconds is represented as poor (X), CD skew is Very good (◎) for 0.8 to 1.0 μm, good (○) for 0.3 to 0.8 μm, and poor (X) for less than 0.3 μm, and very good (◎) for taper angles of 40 to 45 °. If it is °, it is excellent (○), and if it is 70 ~ 90 °, it is indicated as bad (X)

TABLE 2 Cu / ITO Etching speed CD skew Taper angle Example 1 ○ ○ ○ Example 2 ○ ◎ ○ Example 3 ◎ ○ ○ Example 4 ◎ ○ ◎ Example 5 ◎ ◎ ◎ Comparative Example 1 ◎ ○ △ Comparative Example 2 ○ ○ △ Comparative Example 3 △ ○ ○ Comparative Example 4 ○ △ △ Comparative Example 5 △ △ △

TABLE 3 Cu / MoTi Etching speed CD skew Taper angle Example 1 ○ ○ ○ Example 2 ○ ○ ◎ Example 3 ◎ ◎ ○ Example 4 ○ ◎ ○ Example 5 ◎ ◎ ◎ Comparative Example 1 ◎ △ ○ Comparative Example 2 ○ △ ○ Comparative Example 3 ○ ○ △ Comparative Example 4 △ △ ○ Comparative Example 5 △ △ △

As shown in Tables 2 and 3 and FIGS. 1 and 2, the etching liquid compositions of Examples 1 to 5 have excellent etching characteristics and CD skew without significant difference, while the taper angle is adjusted to 40 to 45 °, The etchant compositions of Comparative Examples 1 to 5 were poor in etching characteristics as the content of some components was too small or too large.

Claims (9)

5-20 wt% hydrogen peroxide; 0.1-5% by weight of sulfonic acid compound; 0.1 to 2 wt% carbonyl organic acid compound; 0.1 to 0.4% by weight of fluorine compound; 0.01-3% by weight of an azole compound; And Etch liquid composition comprising the remaining water. The content of the hydrogen peroxide is 5 to 15% by weight, the content of the sulfonic acid compound is 0.2 to 3% by weight, the content of the carbonyl organic acid compound is 0.1 to 1% by weight, the content of the fluorine compound Is 0.1 to 0.2% by weight, the content of the azole compound is 0.05 to 1% by weight, and the etching liquid composition is to etch a double film of a copper film and an indium tin oxide film or a double film of a copper film and a metal film simultaneously, Composition. The etchant composition according to claim 1, wherein the carbonyl organic acid compound is a compound selected from the group consisting of malonic acid, succinic acid, formic acid, lactic acid, and mixtures thereof. The etchant composition of claim 1, wherein the sulfonic acid compound is a compound selected from the group consisting of benzenesulfonic acid, toluenesulfone, methanesulfonic acid, aminosulfonic acid, salts thereof, and mixtures thereof. The method of claim 1, wherein the fluorine compound is selected from the group consisting of KF, NaF, NH ₄ F, NH ₄ HF ₂ , H ₂ SiF ₆ , HBF ₄ , H ₂ TiF ₆ , H ₂ ZrF ₆ and mixtures thereof Phosphorus, etchant composition. The etchant composition of claim 1, wherein the azole compound is selected from the group consisting of benzotriazole, aminotetrazole, imidazole, pyrazole, and mixtures thereof. Forming a photoresist pattern having a predetermined shape on the substrate on which the metal film is formed; And Using the photoresist pattern as a mask and contacting an etchant composition to etch and remove the metal film from the substrate, The etchant composition comprises 5 to 20 wt% hydrogen peroxide, 0.1 to 5 wt% sulfonic acid compound, 0.1 to 2 wt% carbonyl organic acid compound, 0.1 to 0.4 wt% fluorine compound, 0.01 to 3 wt% azole compound , And remaining water. The etching method according to claim 7, wherein the metal film is a double film of a copper film / indium tin oxide film formed by stacking a copper film and an indium tin oxide film. The etching method according to claim 7, wherein the metal film is a double film of a copper film / metal film formed by laminating a copper film and a metal film.

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