KR20100040352A - Cu or cu alloy ething liquid with high selectivity and method for fabricating lcd thereof - Google Patents

Abstract

PURPOSE: An etching solution is provided to improve the reliability and yield of a liquid crystal display while not damaging the other metal layer except for copper exposed to the etchant. CONSTITUTION: An etching solution for selectively etching a multilayer containing copper(copper alloy)/titanium, molybdenum or molybdenum alloy layer, and a copper or copper alloy layer form a copper or copper alloy monolayer. The etching solution comprises 5~20 weight% hydrogen peroxide liquid, 1~5 weight% phosphoric acid, 0.1~5 weight phosphoric acid, 0.1~10 weight% chelating agent, 0.1~5 weight% annular amine, and 0.1 ~ 5 weight% cyclic amine compound, and the amount to be 100 weight% of the whole composition.

Description

Cu or Cu alloy ething liquid with high selectivity and method for fabricating LCD

The present invention relates to a metallization etching solution, a metallization etching method using the same, and a method of manufacturing a liquid crystal display device using the etching solution.

In order to form a metal wiring on a substrate in a semiconductor device, a metal film forming process is generally performed by sputtering or the like, a photoresist forming process having a predetermined pattern on the metal film, and an etching process of performing etching using the photoresist as a contact mask. Among these, the etching process is performed by dry etching using a plasma or the like, or wet etching using an etching solution. In the case of dry etching, since etching conditions are difficult and expensive, such as requiring a high vacuum, wet etching is more advantageous when an appropriate etching solution is present.

On the other hand, the resistance of the metallization film in the TFT-LCD device is a major factor causing the RC signal delay, and obtaining a low resistance metallization film is a key to increasing the panel size and high resolution. Therefore, in the prior art, chromium (Cr, specific resistance: 25 x 10 < -6 > m), molybdenum (Mo, specific resistance: 12 x 10 < -6 > 10-6 lm) and their alloys are considered to be unfavorable for use as gates and data wirings used in large TFT-LCDs due to their high resistance.

In this regard, copper metals, which are significantly lower in resistance than aluminum or chromium and have no environmental problems, are attracting attention as low-resistance wiring film materials. However, in the case of copper, a process of coating and patterning a photoresist on the metal film There are many problems, such as poor adhesion to the glass substrate and the silicon insulating film. Rather than using copper alone to solve this problem, a technique of using an intermediate metal film together to increase the adhesion between the copper film and the lower glass substrate or the silicon insulating film and to suppress the diffusion of copper into the silicon film has been proposed. The intermediate metal film may be titanium, molybdenum or molybdenum alloy.

The etching of copper in the metal wiring is mainly performed by using an etching solution such as ferric chloride + hydrochloric acid (FeCl ₃ + HCl) and ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ). Most of these etching solutions have a high etching rate, but the etching solution composition is unstable and easily decomposed, and thus, the selectivity to copper etching is poor, thereby damaging other metal films exposed to the etching solution such as titanium, molybdenum, or molybdenum alloy. Therefore, there is a need to develop a highly selective copper etching solution that does not damage other metal films such as titanium, molybdenum, or molybdenum alloy while having an etching on the copper film.

An object of the present invention is to meet the above needs and to etch a copper metal layer in a copper (or copper alloy) layer containing a copper (or copper alloy) layer, a multilayer film containing a titanium, molybdenum or molybdenum alloy layer and a copper single layer. It is to provide a highly selective copper etching solution composition that can be.

The etching solution of the present invention is a highly selective copper etching solution, which hardly damages other metal films other than copper exposed to the etching solution, and thus helps to improve the reliability and yield of the liquid crystal display device compared to the conventional etching solution. In addition, since most of the composition is made of water has the advantage of low manufacturing cost.

In order to achieve the above technical problem, in the present invention, the copper metal layer may be etched in a multilayer and a single film containing a copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer by mixing hydrogen peroxide, phosphoric acid and water in an appropriate ratio. To provide a high selectivity copper etching solution composition, and to improve the properties of the etching solution further comprises an additive comprising a phosphate and nitrogen. More specifically, the present invention is 5 to 20% by weight of hydrogen peroxide, 1 to 5% by weight phosphoric acid, 0.1 to 5% by weight phosphate and 0.1 to 10% by weight chelating agent, 0.1 to the total weight of the composition An etching solution containing 5% by weight of a cyclic amine compound and water such that the total weight of the total composition is 100% by weight, wherein the multilayer film and the single film containing the copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer are selectively selected. Can be etched with

Hydrogen peroxide contained in the etching solution of the present invention is used as the main oxidant of the copper metal film. Hydrogen peroxide solution is added in an amount of 5-20% by weight relative to the total weight of the total composition. If the content of hydrogen peroxide is too high, there is a risk of explosion due to catalysis in the presence of metal ions in the solution, which is disadvantageous for securing stability. If the content of hydrogen peroxide is too low, the copper metal film is not etched smoothly, the copper metal film remains as a residue, or the etching speed of the copper metal film is significantly reduced, making it difficult to apply the process.

Phosphoric acid contained in the etching solution of the present invention is added in an amount of 1 to 5% by weight based on the total weight of the total composition, and provides hydrogen ions in the solution to facilitate the visualization of the hydrogen peroxide copper. In addition, it combines with oxidized copper ions to form a phosphate to increase the solubility in water to remove the residue of the copper metal film after etching. However, if the phosphoric acid content is excessively high, there is a possibility that the etching of the copper metal film and other metal films may be corroded by phosphoric acid, and if the phosphoric acid content is too low, the etching rate of the copper metal film is decreased, so that the corrosion of other metal films does not occur. Is added in the amount of.

The phosphate added in an amount of 0.1 to 5% by weight relative to the total weight of the total composition includes ammonium monophosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate and dihydrogen phosphate. Compounds characterized in that hydrogen in phosphoric acid, such as potassium dihydrogen phosphate, is selected from one, two or three substituted salts of ammonium or alkali metals and alkaline earth metals, are all applicable, alone or in combination It can be used as a mixture of the above.

Phosphate does not directly affect the etching characteristics, but maintains the constant concentration of hydrogen ions participating in copper oxidation by hydrogen peroxide solution, thus maintaining the etching characteristics after initial etching of a large number of substrates. . However, when the content of the phosphate is too high, the etching rate is lowered, so that it is difficult to apply the process.

Chelating agent added in an amount of 0.1 to 10% by weight based on the total weight of the total composition, alanine series, aminobutyric acid series, glutamic acid series, glycine series, iminodi Water-soluble compounds having amino and carboxylic acid groups, such as acetic acid series, nitrilotriacetic acid series, sarcosine series, etc., are all applicable and can be used alone or as mixtures of two or more thereof. Can be. Nitrogen-containing additives do not directly affect the etching characteristics, but increase the storage period by slowing the rate of self-decomposition of hydrogen peroxide water, which can occur when the liquid is stored. It is possible to prevent the etching characteristics from changing when a large amount of copper ions remain in the substrate.

The cyclic amine compound added in an amount of 0.1 to 5% by weight based on the total weight of the total composition is not particularly limited, for example, aminotetrazole, benzotriazole, methylbenzotriazole ( Methyl-benzotriazol), 1,2,3 triazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, pyrrole, pyrroline and the like can be used.

When the cyclic amine compound is not added to the metallization etching solution according to the present invention, not only the etching rate for copper can be controlled but also the CD loss is increased and the linearity of the wiring is also lowered, thereby causing serious problems in the production process. Can cause.

As an example of the metallization etching method using the etching solution, depositing a molybdenum (alloy) film on the substrate; Depositing a copper film on the molybdenum (alloy) film; Forming a photoresist film having a predetermined pattern on the substrate; Forming a metal wiring by wet etching the copper (copper alloy) / molybdenum (alloy) film using the etching solution according to the present invention using the photoresist film as a mask; Removing the photoresist film; Washing the metal wire with deionized water and drying the same with nitrogen to form an electrode.

The structure of a thin film transistor (TFT) of a liquid crystal display includes forming a gate electrode on a substrate; Forming a gate insulating layer on the substrate including the gate electrode; Forming a semiconductor layer on the gate insulating layer; Forming a source and a drain electrode on the semiconductor layer; And forming a pixel electrode connected to the drain electrode, wherein the method of forming the gate electrode, the source and drain electrodes, and the pixel electrode is performed through a metal wiring etching method as described above.

The copper (copper alloy) / molybdenum (alloy) film is a multilayer film in which a copper (Cu) film, a molybdenum (Mo) film, and / or a molybdenum alloy (Mo-alloy) film are laminated to each other. The molybdenum (alloy) film is about 100 ~ 500Å, the copper film is characterized in that deposited to have a thickness of about 1000 ~ 5000Å.

The metal film thicknesses are not limited to each other, and may be appropriately adjusted as necessary. The term 'molybdenum alloy film' means a molybdenum film containing a metal component capable of forming an alloy with molybdenum such as tungsten, titanium, niobinium, chromium, and tantalum. For example, molybdenum- Tungsten (Mo-W), molybdenum-titanium (Mo-Ti), molybdenum-niobium (Mo-Nb), molybdenum-chromium (Mo-Cr) molybdenum-tantalum (Mo- Ta) etc. can be mentioned.

As described above, the etching solution according to the present invention is titanium, molybdenum or the like used in particular as an intermediate metal film to increase the adhesion between the copper film and the lower glass substrate or the silicon insulating film and to suppress the diffusion of copper into the silicon film. Improved reliability and yield of liquid crystal display device by minimizing attack on molybdenum alloy and the like, etching method using same as etching liquid composition of copper metal film having uniform etching characteristics, and manufacturing of TFT array substrate for liquid crystal display device using the same Provide a method.

Hereinafter, the present invention will be described in more detail with reference to comparative examples and examples.

However, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below.

(Example 1)

15% by weight hydrogen peroxide, 3% by weight phosphoric acid, 0.5% by weight sodium dihydrogen phosphate as phosphate, 2% by weight iminodiacetic acid as chelating agent, 0.3% by weight imidazole as cyclic amine compound and 100% by weight of total composition To prepare an etching solution consisting of water to be%.

This etching solution is used to perform an etching process of a copper (copper alloy) / molybdenum alloy film at 30 ° C. The substrate was formed using a photoresist film having a predetermined pattern after deposition such that the molybdenum (alloy) film has a thickness of about 100 to 500 mW and the copper film has a thickness of about 1000 to 5000 mW. The etching solution was sprayed onto the glass substrate by spraying at 30 ° C. for 60 seconds, followed by an etching process, followed by washing with deionized water and drying with nitrogen. After drying, the profile of the copper (copper alloy) / molybdenum (alloy) film etched through the above method was examined using a cross-sectional SEM (S-4700 by Hitachi), and the metal film surface was observed. The result is shown in FIG.

FIG. 1 is a photograph showing an electron microscope of a copper (copper alloy) / molybdenum alloy film wet-etched with the etching solution.

As shown in FIG. 1, the copper etching solution of the present invention shows little loss of molybdenum alloy film due to galvanic corrosion after etching.

(Examples 2-14)

In an analogous manner to that in Example 1, an etching solution was prepared by varying the composition ratio of hydrogen peroxide, phosphoric acid, sodium dihydrogen phosphate, imino diacetic acid, imidazole and water. Using this etching solution, the etching process of a copper (copper alloy) / molybdenum alloy film is performed several times at 30 degreeC.

The profile of the copper (copper alloy) / molybdenum alloy film etched through the above method was examined using a cross-sectional SEM (S-4700, manufactured by Hitachi), and the metal film surface was observed. Table 1 shows the composition of Examples 2 to 14, the damage of the molybdenum alloy film and the presence of copper film residue, and the degree of etching of the copper film. As shown in Table 1, the copper etching solution having the composition component and the composition ratio according to the present invention has high selectivity without damage of the molybdenum alloy film and no residue of the copper film and shows good results.

[Test result display criteria]

X: No molybdenum alloy film damage, no copper film residue

O: molybdenum alloy film damage is present, copper film residue is present

Table 1

 (Comparative Examples 1 to 3)

In an analogous manner to that in Example 1, an etching solution was prepared by varying the composition ratio of hydrogen peroxide, phosphoric acid, sodium dihydrogen phosphate, imino diacetic acid, imidazole and water. Using this etching solution, the etching process of a copper (copper alloy) / molybdenum alloy film is performed several times at 30 degreeC.

The profile of the copper (copper alloy) / molybdenum alloy film etched through the above method was examined using a cross-sectional SEM (S-4700, manufactured by Hitachi), and the metal film surface was observed. Table 2 shows the compositions of Comparative Examples 1 to 3, the damage of the molybdenum alloy film and the presence of copper film residues, and the degree of etching of the copper film.

As shown in Table 2, the residue of the copper film occurs in the absence of phosphoric acid, the damage of the molybdenum alloy film occurs in the absence of the phosphate salt, and in the absence of the imidazole which is a cyclic amine compound, the copper film has a high etching rate and thus a large CD loss. .

[Test Result Display Criteria]

X: No molybdenum alloy film damage, no copper film residue

O: molybdenum alloy film damage is present, copper film residue is present

Table 2

(Comparative Examples 4-5)

An etching solution consisting of 30% by weight of ferric chloride, 1% by weight of hydrochloric acid, and 100% by weight of the total composition, 15% by weight of ammonium persulfate, and 100% by weight of the total composition An etching solution is prepared.

The etching process was performed in the same manner as in Example 1, and the results are shown in Table 3 and FIGS. 2 and 3.

2 is a photograph showing an electron microscope of a copper (copper alloy) / molybdenum alloy film wet-etched with an etching solution using ferric chloride according to the prior art.

FIG. 3 is a photograph showing an electron microscope of a copper (copper alloy) / molybdenum alloy film wet-etched with an etching solution using ammonium persulfate according to the prior art.

As shown in Figures 2 and 3, the copper etching solutions of Comparative Examples 4 to 5 according to the prior art show that the loss of the molybdenum alloy film due to galvanic corrosion after etching is very large.

Table 3

(Examples 15-16)

In the same manner as in Example 1, an etching solution was prepared by varying the composition ratio of hydrogen peroxide water, phosphoric acid, phosphate, chelating agent and water, and then 1000 ppm of copper powder was added to the etching solution. After 8 days, the remaining amount of fruit is analyzed and the results are shown in Table 3.

As shown in Table 4, the copper etching solution of Example 15 shows that the chelating agent reduces the decomposition rate of hydrogen peroxide solution by copper ions in the solution. Therefore, even after etching a large number of substrates with a copper etching solution having a composition component and composition ratio according to the present invention it can be seen that the etching characteristics are maintained similar to the initial.

Table 4

1 is a photograph showing an electron microscope of a copper / molybdenum alloy film wet-etched with an etching solution according to the present invention.

2 is a photograph showing an electron microscope of a copper / molybdenum alloy film wet-etched with an etching solution containing ferric chloride and hydrochloric acid according to the prior art.

FIG. 3 is a photograph showing an electron microscope of a copper / molybdenum alloy film wet-etched with an etching solution containing ammonium persulfate according to the prior art.

Claims (11)

5-20 weight percent hydrogen peroxide, 1-5 weight percent phosphoric acid, 0.1-5 weight percent phosphate, 0.1-10 weight percent chelating agent, 0.1-5 weight percent cyclic amine relative to the total weight of the total composition Selectively selecting a copper or copper alloy layer from a copper (copper alloy) / multilayer film containing a titanium, molybdenum or molybdenum alloy layer and a copper or copper alloy single film containing water such that the total weight of the compound and the total composition is 100% by weight Etch solution composition to be etched. The method of claim 1, The phosphate is a compound in which at least one hydrogen in phosphoric acid is substituted with ammonium, an alkali metal or an alkaline earth metal, ammonium monophosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, and Selecting a copper or copper alloy layer from a copper (copper alloy) / multilayer film containing a titanium, molybdenum or molybdenum alloy layer selected from a compound such as potassium dihydrogen phosphate or mixtures thereof and a single layer of copper or copper alloy Etch solution composition to be etched by. The method of claim 1, The chelating agent is a copper or copper alloy layer from a copper or copper alloy single layer containing a copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer selected from a water-soluble compound having an amino group and a carboxylic acid group or a mixture thereof Etch liquid composition for selectively etching. The method of claim 3, wherein The chelating agent is a multilayer film containing a copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer selected from alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, nitrilotriacetic acid, sarcosine or mixtures thereof and copper or copper alloy An etchant composition for selectively etching a copper or copper alloy layer from a single film. The method of claim 1, Copper selected from benzotriazole, aminoterazole-based compound, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, pyrrole, pyrroline or a mixture thereof (Copper alloy) / An etchant composition for selectively etching a copper or copper alloy layer from a multilayer film containing a titanium, molybdenum or molybdenum alloy layer and a copper or copper alloy single film. The method of claim 5, Aminotetrazole-based compound is aminotetrazole, benzotriazole, methyl-benzotriazol, 1,2,3 triazole, or a compound thereof An etching liquid composition for selectively etching a copper or copper alloy layer from a multilayer film containing a copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer selected from the mixture and a copper or copper alloy single film. The method of claim 1, An etching solution composition for selectively etching a copper or copper alloy layer from a copper (copper alloy) / multilayer film containing a titanium, molybdenum or molybdenum alloy layer and a copper or copper alloy single film, wherein water is deionized water. The method of claim 1, Copper or copper alloy from a copper (copper alloy) / multilayer film containing a titanium, molybdenum or molybdenum alloy layer and a copper or copper alloy single film further comprising at least one additive selected from surfactants, metal ion sequestrants, and corrosion inhibitors An etchant composition for selectively etching the layer. The method of claim 1, Molybdenum alloy film means a molybdenum film containing a metal component capable of alloying with molybdenum such as tungsten, titanium, niobinium, chromium and tantalum. For example, molybdenum-tungsten (Mo-W), molybdenum-titanium (Mo-Ti), molybdenum-niobium (Mo-Nb), molybdenum-chromium (Mo-Cr) molybdenum-tantalum (Mo-Ta) An etchant composition for selectively etching a copper or copper alloy layer from a multilayer film containing a copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer and a copper or copper alloy single film, which are laminated multilayer films. A copper (copper alloy) single film or a copper (copper alloy) / copper containing copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer using the highly selective copper (copper alloy) etchant composition according to claims 1 to 8 Alloy) a method of manufacturing a TFT-LCD array substrate for a liquid crystal display device comprising the step of etching a copper or copper alloy layer from a multilayer film. The method of claim 10, Forming a gate electrode on the substrate; Forming a gate insulating layer on the substrate including the gate electrode; Forming a semiconductor layer on the gate insulating layer; Forming a source and a drain electrode on the semiconductor layer; And forming a pixel electrode connected to the drain electrode; a copper (copper alloy) single layer or a multi-layer layer as a metal wiring material for the gate, source and drain, and pixel electrode of the liquid crystal display (LCD). A method of manufacturing a TFT array substrate for a liquid crystal display device comprising the step of etching a copper alloy).

Images