KR101495619B1 - Cu or Cu alloy ething liquid with high selectivity and method for fabricating LCD thereof - Google Patents

Abstract

The present invention relates to a new type of etching solution composition having a high selectivity in copper (or copper alloy) film etching. The etching solution composition of the present invention comprises 5 to 20% by weight of hydrogen peroxide, 1 to 5% by weight of phosphoric acid, 0.1 to 5% by weight of phosphate, 0.1 to 10% by weight of chelating agent, 0.1 to 5% by weight of a cyclic amine compound and water so that the total weight of the total composition is 100% by weight.

The etching solution according to the present invention is an etching solution 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 (copper alloy) An etchant composition of a copper metal film having uniform etching properties, which improves the reliability and yield of a liquid crystal display device by minimizing attack on titanium, molybdenum or molybdenum alloy used as a film, and a method of etching using the same, A method of manufacturing a TFT-LCD array substrate for a display device is provided.

Etching solution, copper (copper alloy), liquid crystal display

Description

[0001] The present invention relates to a copper (copper alloy) etchant having a high selectivity and a method of manufacturing a liquid crystal display using the same,

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

In order to form a metal wiring on a substrate in a semiconductor device, a metal film forming process 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 The etching process is performed by dry etching using plasma or wet etching using an etching solution. In the case of dry etching, wet etching is more advantageous in the presence of an appropriate etching solution because etching conditions such as high vacuum are difficult and expensive.

On the other hand, in the TFT-LCD device, the resistance of the metal wiring film is a major factor causing the RC signal delay, and the low resistance metal wiring film is a key factor in increasing the panel size and realizing high resolution. Therefore, it is preferable to use chromium (Cr, specific resistance: 25 x 10-6? M), molybdenum (Mo, specific resistance: 12 x 10-6? M), aluminum niobium (AlNd, 10-6? M) and their alloys are considered to be undesirable for use in gates and data wirings used in large-scale TFT-LCDs due to their high resistance.

In this connection, copper metal, which is significantly lower in resistance than aluminum or chromium and has no great environmental problems, has attracted attention as a low resistance wiring film material. However, in the case of copper, a step of coating and patterning photoresist on the metal film There is a problem that adhesion to a glass substrate and a silicon insulating film is deteriorated. In order to solve such a problem, there has been proposed 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, rather than using copper alone Examples of the intermediate metal film include titanium, molybdenum or molybdenum alloy, and the like

Etching for copper in metal wiring is mainly performed using etching solutions such as ferric chloride + hydrochloric acid (FeCl ₃ + HCl) and ammonium peroxodisulfate ((NH ₄ ) ₂ S ₂ O ₈ ). Most of these etching solutions have a disadvantage in that they are susceptible to decomposition due to instability of the etching solution composition due to the high etching rate, and they have poor selectivity to copper etching and damage other metal films exposed to the etching solution such as titanium, molybdenum or molybdenum alloy. Therefore, it is required to develop a highly selective copper etching solution that does not damage other metal films such as titanium, molybdenum, or molybdenum alloy while having etching for the copper film.

An object of the present invention is to provide a copper (copper alloy) layer containing a copper (or copper alloy) film, a multilayer film containing a titanium, molybdenum or molybdenum alloy layer, The copper etching solution composition of the present invention.

The etching solution of the present invention is a high selectivity copper etching solution which hardly causes damage to the metal film other than copper exposed to the etching solution, thereby contributing to the improvement of the reliability and yield of the liquid crystal display device compared with the conventional etching solution. In addition, since most of the composition is composed of water, the manufacturing cost is low.

In order to accomplish the above object, according to the present invention, there is provided a method for etching a copper metal layer in a multilayered film and a single film containing a copper (copper alloy) / titanium, molybdenum or molybdenum alloy layer by mixing hydrogen peroxide water, phosphoric acid and water in an appropriate ratio And further comprising an additive comprising phosphorous and nitrogen to improve the properties of the etch solution. More specifically, the present invention relates to a composition comprising 5 to 20% by weight of hydrogen peroxide, 1 to 5% by weight of phosphoric acid, 0.1 to 5% by weight of phosphate and 0.1 to 10% (Copper alloy) / titanium, molybdenum or molybdenum alloy layer and a single layer of a single layer are selectively etched with an etching solution containing 5 wt% of a cyclic amine compound and water to make the total weight of the entire composition 100 wt% . ≪ / RTI >

The hydrogen peroxide solution contained in the etching solution of the present invention is used as a main oxidizing agent of the copper metal film. The hydrogen peroxide solution is added in an amount of 5 to 20% by weight based on the total weight of the total composition. If the content of hydrogen peroxide is excessively high, there is a risk of explosion due to catalysis in the presence of metal ions in the solution, thereby deteriorating stability. If the content of the hydrogen peroxide solution is too low, the copper metal film is not smoothly etched, the copper metal film remains as a residue, or the etching rate of the copper metal film is significantly lowered, making the process application difficult.

The 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 hydrogen ions are provided in the solution to accelerate the copper of the hydrogen peroxide solution. In addition, it binds to oxidized copper ions and forms a phosphate to increase the solubility in water, thereby eliminating residues of copper metal film after etching. However, if the content of phosphoric acid is excessively high, there is a possibility that excessive etching of the copper metal film and the other metal film may be corroded by the phosphoric acid, and if the phosphoric acid content is decreased too much, the etching rate of the copper metal film is lowered, Lt; / RTI >

The phosphate added in an amount of 0.1 to 5 wt% based on the total weight of the total composition may be selected from the group consisting of ammonium monophosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, Compounds such as potassium dihydrogen phosphate, in which the hydrogen is selected from one, two, or three substituted salts of ammonium, alkali metal and alkaline earth metal, are all applicable, Can be used as the above mixture.

Phosphate does not directly affect the etch characteristics, but it maintains the concentration of hydrogen ions participating in the copper oxidation by the hydrogen peroxide water constantly, thereby maintaining the etch characteristics at a similar level even after etching a large number of substrates . However, if the content of phosphate is excessively high, it is preferable to add the phosphorus in an appropriate concentration range because the etching rate is low and the process application becomes difficult.

The chelating agent to be added in an amount of 0.1 to 10 wt% based on the total weight of the total composition may be selected from the group consisting of alanine series, aminobutyric acid series, glutamic acid series, glycine series, Soluble compounds having an amino group and a carboxylic acid group such as iminodiacetic acid series, nitrilotriacetic acid series and sarcosine series are applicable and can be used singly or as a mixture of two or more kinds . The nitrogen additive has no direct effect on the etch characteristics, but it slows down the self-decomposition rate of hydrogen peroxide water which may occur during the storage of the liquid, increases the storage period, and inactivates the etched copper ions through the multi- It is possible to prevent the etching property from being changed when a large amount of copper ions remain in the etching solution.

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 and includes, for example, aminotetrazole, benzotriazole, methylbenzotriazole Methyl-benzotriazole, 1,2,3-triazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, pyrrole and pyrroline.

If the cyclic amine compound is not added to the metal line 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. You can.

As an example of the method of etching a metal wiring using the etching solution, there is a method of depositing a molybdenum (alloy) film on a 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; And washing and drying the metal wiring with deionized water to form an electrode.

The structure of a TFT (Thin Film Transistor) of a liquid crystal display device 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 source and drain electrodes on the semiconductor layer; And forming a pixel electrode connected to the drain electrode. The method of forming the gate electrode, the source and the drain electrode, and the pixel electrode is performed through the metal wiring etching method as described above.

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

Each of the metal film thicknesses is not limited to each other, and can be appropriately adjusted as needed. The term 'molybdenum alloy film' means a molybdenum film containing a metal component capable of forming an alloy with molybdenum, such as tungsten, titanium, niobium, chromium, and tantalum. Examples of the molybdenum alloy film include molybdenum- Mo-W, molybdenum-titanium, molybdenum-niobium, molybdenum-molybdenum-molybdenum-tantalum, Ta).

As described above, the etching solution according to the present invention is particularly suitable for use as an intermediate metal film for increasing adhesion between a copper film and a lower glass substrate or a silicon insulating film and suppressing diffusion of copper into a silicon film. An etchant composition of a copper metal film having uniform etching characteristics, which improves the reliability and yield of a liquid crystal display device by minimizing an attack on a molybdenum alloy or the like, and a manufacturing method of a TFT array substrate for a liquid crystal display using the same ≪ / RTI >

Hereinafter, the present invention will be described more specifically with reference to Comparative Examples and Examples.

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

(Example 1)

15% by weight of hydrogen peroxide, 3% by weight of phosphoric acid, 0.5% by weight of dihydrogenphosphate as a phosphate, 2% by weight of iminodiacetic acid as a chelating agent, 0.3% by weight of imidazole as a cyclic amine compound and a total weight of 100% %. ≪ / RTI >

The etching process of the copper (copper alloy) / molybdenum alloy film is performed at 30 ° C. using this etching solution. The molybdenum (alloy) film was deposited to a thickness of about 100 to 500 angstroms, and the copper film was deposited to have a thickness of about 1000 to 5000 angstroms. After the deposition, a photoresist film having a predetermined pattern was formed. The etching solution was sprayed on the glass substrate at 30 ° C. for 60 seconds by spraying, followed by etching with deionized water and drying with nitrogen. After drying, the profile of the copper (copper alloy) / molybdenum (alloy) film etched by the above method was inspected using a cross-sectional SEM (Hitachi S-4700) and the surface of the metal film was observed. The results are shown in Fig.

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

As shown in FIG. 1, the copper etching solution of the present invention shows almost no loss of the molybdenum alloy film due to galvanic corrosion after etching.

(Examples 2 to 14)

In a manner similar to that in Example 1, an etching solution was prepared by varying the composition ratio of hydrogen peroxide, phosphoric acid, sodium dihydrogenphosphate, iminodiacetic acid, imidazole and water. This etching solution is used to etch the copper (copper alloy) / molybdenum alloy film several times at 30 ° C.

The profile of the copper (copper alloy) / molybdenum alloy film etched by the above method was inspected using a cross-sectional SEM (Hitachi S-4700) and the surface of the metal film was observed. Table 1 shows the compositions of Examples 2 to 14, the damage of the molybdenum alloy film, 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 components and the composition ratios according to the present invention has high selectivity without damaging the molybdenum alloy film, and without copper film residue, and shows good results.

[Test result display standard]

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

O: Molybdenum alloy film damage, copper film residue

Table 1

 (Comparative Examples 1 to 3)

In a manner similar to that in Example 1, an etching solution was prepared by varying the composition ratio of hydrogen peroxide, phosphoric acid, sodium dihydrogenphosphate, iminodiacetic acid, imidazole and water. This etching solution is used to etch the copper (copper alloy) / molybdenum alloy film several times at 30 ° C.

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

As shown in Table 2, copper film residue is generated in the absence of phosphoric acid, and damage to the molybdenum alloy film occurs in the absence of phosphate. In the absence of imidazole, which is a cyclic amine compound, the etching rate of the copper film is too fast, .

[Test result display standard]

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

O: Molybdenum alloy film damage, copper film residue

Table 2

(Comparative Examples 4 to 5)

An etching solution consisting of 30% by weight of ferric chloride, 1% by weight of hydrochloric acid and water to make the total weight of the entire composition 100% by weight, 15% by weight of ammonium peroxodisulfate and water to make the total weight of the entire composition 100% To prepare the etching solution.

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

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

FIG. 3 is a photomicrograph of a copper (copper alloy) / molybdenum alloy film wet-etched with an etching solution using peroxodisulfuric acid ammonium according to the prior art.

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

Table 3

(Examples 15 to 16)

In the same manner as in Example 1, an etching solution was prepared by changing the composition ratio of hydrogen peroxide, phosphoric acid, phosphate, chelating agent, and water, and 1000 ppm of copper powder was added to this etching solution. After 8 days, the remaining amount of water was 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 rate of decomposition of hydrogen peroxide by copper ions in the solution. Therefore, it can be seen that even after etching a large number of substrates with a copper etching solution having composition components and composition ratios according to the present invention, the etching characteristics are maintained at the initial level.

Table 4

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

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

3 is a photomicrograph of a copper / molybdenum alloy film wet-etched with an etching solution containing ammonium peroxodisulfate according to the prior art.

Claims (11)

The amount of hydrogen peroxide, 1-5 wt% of phosphoric acid, 0.5-5 wt% of phosphate, 2-10 wt% of chelating agent, 0.1-5 wt% of cyclic amine A composition for etching a copper or copper alloy layer selectively from a multilayer film containing a copper or copper alloy layer and a molybdenum or molybdenum alloy layer comprising water such that the total weight of the compound and the total composition is 100 wt%. The method according to claim 1, The phosphate is a compound in which at least one hydrogen in phosphoric acid is substituted with an ammonium, an alkali metal or an alkaline earth metal and includes ammonium monophosphate, ammonium dihydrogen phosphate, sodium dihydrogen phosphate, Wherein the copper or copper alloy layer is selectively etched from a multilayer film containing a copper or copper alloy layer and a molybdenum or molybdenum alloy layer selected from a compound such as potassium dihydrogen phosphate or a mixture thereof. The method according to claim 1, Wherein the chelating agent selectively etches copper or a copper alloy layer from a multilayer film containing a copper or copper alloy layer and a molybdenum or molybdenum alloy layer selected from a water-soluble compound having an amino group and a carboxylic acid group or a mixture thereof. The method of claim 3, The chelating agent may be a copper or copper alloy layer selected from alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, nitrilotriacetic acid, sarcosine or a mixture thereof, and a layer of copper or copper alloy from a multilayer film containing a molybdenum or molybdenum alloy layer RTI ID = 0.0 > etchant < / RTI > The method according to claim 1, The cyclic amine compound may be selected from the group consisting of aminotetrazole, benzotriazole, methyl-benzotriazole, 1,2,3-triazole, imidazole, A copper or copper alloy layer is selectively formed from a multilayer film containing a copper or copper alloy layer and a molybdenum or molybdenum alloy layer selected from indole, purine, pyrazole, pyridine, pyrimidine, pyrrole, ≪ / RTI > delete The method according to claim 1, Wherein the copper or copper alloy layer is selectively etched from a multilayer film containing a copper or copper alloy layer in which water is deionized water and a molybdenum or molybdenum alloy layer. The method according to claim 1, Wherein the copper or copper alloy layer is selectively etched from a multilayer film containing a copper or copper alloy layer and a molybdenum or molybdenum alloy layer further comprising at least one additive selected from a surfactant, a sequestering agent, and a corrosion inhibitor. The method according to claim 1, The molybdenum alloy film may be at least one selected from the group consisting of molybdenum-tungsten (Mo-W), molybdenum-titanium (Mo-Ti), molybdenum-niobium (Mo-Nb), molybdenum- ) Or molybdenum-tantalum (Mo-Ta), and a copper or copper alloy layer and a multilayer film containing a molybdenum or molybdenum alloy layer are selectively etched in the copper or copper alloy layer. A method for etching a copper or copper alloy layer from a multilayer film containing a copper or copper alloy layer and a molybdenum or molybdenum alloy layer using the etching composition of any one of claims 1 to 5, 7 or 8 Wherein the step of forming the TFT-LCD array substrate comprises the steps of: 11. 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 source and drain electrodes on the semiconductor layer; And forming a pixel electrode connected to the drain electrode, wherein the gate, source and drain, and the metal wiring material for the pixel electrode constituting the TFT of the liquid crystal display device are made of a copper or copper alloy layer and a molybdenum or molybdenum alloy layer And etching the copper or copper alloy layer from one multilayer film.

Images