KR101406573B1 - Etchant composition and method for fabricating metal pattern - Google Patents

Abstract

The present invention is based on the total weight of the composition, 0.5 to 20% _{(NH 4) 2 S 2 O} 8; 0.1 to 5% by weight of phosphate; 0.01 to 1% by weight of a fluorine-containing compound; 0.01 to 1% by weight of heterocyclic amine And at least one nitrogen compound selected from aminocarboxylic acid compounds; And 73 to 99.38% by weight of water, and a method for forming a metal pattern using the same.

Copper, molybdenum, etchant

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etchant composition and a method for forming a metal pattern using the same,

The present invention relates to a wet etchant composition related to copper and molybdenum and to the formation of metal patterns using the same.

Generally, the process of forming a metal wiring on a substrate in a semiconductor device and a flat panel display device is usually performed by a metal film forming process by sputtering, a photoresist coating process, a photoresist forming process in an optional region by exposure and development, And includes a cleaning process before and after the individual unit process, and the like.

This etching process refers to a process of leaving a metal film in a selective region by using a photoresist mask. Dry etching using plasma or wet etching using an etching solution is usually used.

Recently, the resistance of metal wiring has become a major concern. Since resistance is a major factor that causes RC signal delay, especially TFT-LCD (thin film transistor - liquid crystal display), it is important to increase panel size and realize high resolution.

Therefore, in order to realize a reduction in the RC delay signal which is indispensable for the enlargement of the TFT-LCD, and is essentially a low resistance materials developed primarily chromium was (Cr resistivity: 12.7 × 10 ^-8 Ωm) in the art, molybdenum ( (Resistivity: 5 × 10 ^-8 Ωm), aluminum (Al resistivity: 2.65 × 10 ^-8 Ωm), and alloys thereof are difficult to use for gate and data wiring used in a large TFT-LCD.

Under these circumstances, interest in copper films, one of the new low resistance metal films, is high. Copper films are known to have a lower resistance than aluminum and chromium films and have no environmental problems. On the other hand, studies on multi-metal films including copper films have been carried out, and in particular, copper-titanium films have been spotlighted. For this copper-titanium double layer, there is a known etchant and a lot of new etchants are disclosed, but due to the special chemical properties of the titanium layer, there is a drawback that no fluorine ions can be etched. However, if fluorine ions are contained in the etching liquid, a glass substrate and various silicon layers (a passivation layer made of a semiconductor layer and a silicon nitride film) are also etched together, which causes problems in the process due to a large number of elements.

Therefore, studies on molybdenum membranes, which are relatively weaker in acid resistance than titanium, are spreading. Copper molybdenum films can be made with copper or molybdenum film thicknesses that are similar or better than copper titanium films, and good processes can be achieved because fluorine ions do not need to be included in the etchant used in etching.

As an etchant for the copper molybdenum film, a mixed solution of phosphoric acid, nitric acid (HNO ₃ ), acetic acid, a salt compound and a fluorine compound was initially used depending on the constitution conditions of the thin film. However, when the copper-molybdenum film is etched using the mixed solutions, that is, when the molybdenum film located at the bottom is etched because the etching speed of the copper located at the upper side is too high, the copper is over-deflected and the copper is left little. As a result, when the external driving voltage is applied, the resistance value inherent to copper can not be shown, which makes it difficult to apply to the process. In addition, the straightness of the wiring is not excellent due to the etching property, and the taper angle is more than 90 degrees, which may cause problems in the subsequent process. Due to such a problem, there are many disadvantages in the practical process, and it is difficult to apply the mixed solutions to the copper-molybdenum film etching.

In addition, recently, an aqueous mixed solution has attracted much attention as an etchant in a flat panel display. However, in the case of the above-mentioned hydrous mixed solution, the concentration changes with time, which causes a problem that affects the number of treatments, that is, the amount of the substrate to be etched. More specifically, in the case of an aqueous mixed solution, when copper is wet-etched, the etched copper is present in the fruit juice. When the amount of copper is saturated and reaches a peak, a rapid temperature rise occurs. As a result, a large accident can be caused in the actual process, and the amount of the process is limited. In addition, in the case of an aqueous mixed solution, an auxiliary equipment is required to carry out the process, which raises a problem of increasing manufacturing costs.

Accordingly, there is a need to develop a new etchant composition which does not react with copper, which is a residue due to wet etching, and exhibits excellent properties in etching to solve the above problems.

In order to solve the problems of the prior art as described above, the present invention can etch the first monolayer including copper and the second monolayer including molybdenum, and at the same time, the first monolayer and the second monolayer, And a method of forming a metal pattern using the same. The present invention also provides a method for forming a metal pattern using the same, which is excellent in etching properties and stability.

The present invention is based on the total weight of the composition, 0.5 to 20% _{(NH 4) 2 S 2 O} 8; 0.1 to 5% by weight of phosphate; 0.01 to 1% by weight of a fluorine-containing compound; 0.01 to 1% by weight of heterocyclic amine And at least one nitrogen compound selected from aminocarboxylic acid compounds; And 73 to 99.38% by weight of water.

In addition,

Forming one or more of a first monolayer comprising copper on the substrate, a second monolayer comprising molybdenum and multiple layers thereof;

And etching the one or a plurality of the formed films with the etching solution composition of the present invention.

The etchant composition of the present invention can etch a first single film comprising copper and a second single film comprising molybdenum, respectively, and simultaneously, a batch etching of multiple films including the first single film and the second single film is also possible . In addition, it provides excellent productivity because the stability of the chemical solution is ensured in the process, the side etching, the residue generation and the damage of the lower film are less and the etching property is uniform, the application to a large area substrate is possible, .

The present invention is based on the total weight of the composition, 0.5 to 20% _{(NH 4) 2 S 2 O} 8; 0.1 to 5% by weight of phosphate; 0.01 to 1% by weight of a fluorine-containing compound; 0.01 to 1% by weight of heterocyclic amine And aminocarboxylic acid compounds At least one nitrogen compound selected; And 73 to 99.38% by weight of water.

(NH ₄ ) ₂ S ₂ O ₈ contained in the etching solution composition of the present invention improves etching uniformity as a component for oxidizing copper. It also acts as an etch inhibitor of molybdenum to enable batch wet etching of the multiple films when etching multiple films comprising the first single film and the second single film.

The _{(NH 4) 2 S 2 O} 8 is, It is preferably contained in an amount of 0.5 to 20% by weight based on the total weight of the composition. (NH ₄ ) ₂ S ₂ O ₈ is contained in an amount less than 0.5% by weight, the etching rate of copper is lowered or unevenness is caused by uneven etching phenomenon, and when it exceeds 20% by weight, do.

The phosphate salt contained in the etchant composition of the present invention reduces the electric effect between molybdenum and copper, thereby preventing the undercut phenomenon that the molybdenum film deeply penetrates to the bottom of the copper film. If phosphate is not present, the molybdenum film may be excessively etched into the bottom of the upper copper film, and in severe cases, the pattern may be removed from the substrate.

The phosphate can be used in the art without any particular limitation. Examples of the phosphate include sodium dihydrogen phosphate, potassium dihydrogen phosphate, phosphoric acid, hydrogen, alkali metal or alkaline earth metal. Lt; / RTI > may be used. These may be used singly or in combination of two or more.

The phosphate salt, It is preferably contained in an amount of 0.1 to 5% by weight based on the total weight of the composition. When the phosphate is contained in an amount of less than 0.1% by weight, a severe undercut phenomenon occurs. When the phosphate is contained in an amount exceeding 5% by weight, the undercut prevention effect does not rise any more. Instead, the etch rate of the lower molybdenum film becomes very slow, unetch) may occur.

The fluorine compound contained in the etchant composition of the present invention oxidizes molybdenum, accelerates the etching rate, and removes the etching residue.

The fluorinated compound may be a compound capable of dissociating into fluorine ion or polyatomic fluorine ion in a solution. The fluorinated compound may be a compound selected from the group consisting of ammonium fluoride, sodium fluoride, potassium fluoride, sodium bisulfate, Or two or more of them may be used in combination.

The fluorinated compound is preferably contained in an amount of 0.01 to 1% by weight based on the total weight of the composition. In the case where the fluorine-containing compound is contained in an amount of less than 0.01% by weight, in the case of the double film including the first single film containing copper and the second single film containing molybdenum, the second single film located below may not be etched, Molybdenum residues may occur in part. In addition, if the content of the lower layer is more than 1 wt%, the lower film is damaged and the etching rate is greatly increased, so that the pattern is lost due to the overeating angle. The lower film means a semiconductor film such as glass and silicon oxide film, silicon nitride film, amorphous silicon, polysilicon, doped amorphous silicon, doped polysilicon, and the like.

The heterocyclic amine contained in the etchant composition of the present invention And aminocarboxylic acid compounds The one or more selected nitrogen compounds are components that control the etch rate of the copper film. In addition, the nitrogen compound prevents the re-adsorption of the organic contaminants left on the copper, so that the attack of the copper can be minimized.

The aminocarboxylic acid compound in the present invention means a compound having an amino group and a carboxylic acid group in one molecule.

The nitrogen compound is preferably contained in an amount of 0.01 to 1% by weight based on the total weight of the composition. If the amount of the nitrogen compound is less than 0.01% by weight, the etching rate of copper can not be controlled and an overeating angle may occur. In addition, if it exceeds 1% by weight, the etching rate of copper may be lowered and the etching time may be prolonged in the process, which may cause a problem in productivity.

The at least one nitrogen compound selected from the heterocyclic amines and the aminocarboxylic acid compounds may be at least one selected from the group consisting of aminotetrazole, benzotriazole, imidazole, indole, purine, Heterocyclic amine compounds such as pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, and pyrroline; And aminocarboxylic acids such as alanine, aminobutyric acid, glutamic acid, glycine, iminodiacetic acid, nitrilotriacetic acid, and sarcosine. And at least one compound selected from the group consisting of a carboxylic acid compound and a carboxylic acid compound.

The water used in the present invention means deionized water and is used for semiconductor processing, preferably water of 18 M / cm or more.

The etchant composition of the present invention may further comprise at least one of an etching control agent, a surfactant, a sequestering agent, a corrosion inhibitor and a pH adjuster in addition to the above-mentioned components.

The present invention also relates to

(a) forming one or more of a first monolayer comprising copper on a substrate, a second monolayer comprising molybdenum and a multilayer thereof;

(b) etching the one or more films formed using the etching solution composition of the present invention.

In the method of forming a metal pattern, the step (a) may include the steps of providing a substrate and forming one or more of the first single film, the second single film, and the multiple film on the substrate . The substrate may be a wafer, a glass substrate, a stainless steel substrate, a plastic substrate, or a quartz substrate. As the method of forming the first monolayer, the second monolayer, and the multilayer on the substrate, various methods known to those skilled in the art can be used, and it is preferable to form the first monolayer, the second monolayer, and the multilayer using a vacuum evaporation method or a sputtering method.

The step (b) may include forming a photoresist on the first monolayer, the second monolayer, and the multilayer, selectively exposing the photoresist using a mask, and exposing the exposed photoresist after Baked, and the post-baked photoresist is developed to form a photoresist pattern. The first monolayer, the second monolayer, and the multilayer having the photoresist pattern formed thereon are etched using the etchant composition of the present invention to complete the metal pattern.

The etching process as described above may be performed according to a method well known in the art, for example, a method of dipping, a method of spraying, and the like. During the etching process, the temperature of the etching solution may be in the range of 30 to 50 ° C., and the optimum temperature may be changed as necessary in consideration of other processes and other factors.

Here, the first monolayer, the second monolayer, and the multilayer thereof may be any one or more of a data line, a scan line, a gate electrode, and a source / drain electrode of a flat panel display device.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the scope of the present invention is not limited by the following examples and comparative examples.

Example  1 to 3, Comparative Example  1 and 2: Etchant  Preparation of composition

The etchant compositions were prepared according to the ingredients and composition ratios shown in Table 1 below.

(NH4) ₂ S ₂ O ₈
(weight%) phosphate
(weight%) Fluorine compound
(weight%) Heterocyclic
Amine compound (% by weight) water
(weight%) Example 1 15 NaH ₂ PO ₄ 0.2 NH ₄ HF ₂ 0.01 CH ₃ N ₅ 0.2 Balance Example 2 20 NaH ₂ PO ₄ 0.2 NH ₄ HF ₂ 0.02 CH ₃ N ₅ 0.3 Balance Example 3 20 NaH ₂ PO ₄ 0.5 NH ₄ HF ₂ 0.1 CH ₃ N ₅ 0.05 Balance Comparative Example 1 2 NaH ₂ PO ₄ 10 NH ₄ HF ₂ 0.05 CH ₃ N ₅ 0.1 Balance Comparative Example 2 30 NaH ₂ PO ₄ 0.1 NH ₄ HF ₂ 0.5 CH ₃ N ₅ 0.01 Balance

Test Example : Etch characteristics  evaluation

A Cu single layer and a Cu / Mo double layer were deposited on the substrate, and the etchant of each of Examples 1 to 3 and Comparative Examples 1 and 2 was placed in a spray type etching equipment (manufactured by SEMES) Lt; 0 > C, and the substrate was etched when the temperature reached 30 +/- 0.1 [deg.] C. The total etch time was set to 40% over etch based on EPD (End Point Detection). After the substrate was injected and the etching was completed, the substrate was taken out, washed with deionized water, dried using a hot air dryer, and photoresist was removed using a photoresist stripper. After washing and drying, Side Etch loss, bottom film damage and etching residue were evaluated using an electron microscope (SEM; model: S-4700, manufactured by HITACHI Corporation)

Types of Thin Films Etch characteristics results Types of Thin Films Etch characteristics results EPD
(sec) S / E
(탆) Bottom membrane
damaged Residue EPD
(sec) S / E
(탆) Bottom membrane
damaged Residue Example 1 Cu 45 0.43 X X Cu / Mo 52 0.55 X X Example 2 32 0.35 X X 40 0.51 X X Example 3 41 0.39 X X 47 0.62 X X Comparative Example 1 Not etched Not etched Comparative Example 2 12 1.82 X X Pattern Loss X X

As can be seen from Table 2, etching of Cu single layer and Cu / Mo double layer using the etching compositions of Examples 1 to 3 according to the present invention is very effective in terms of side etching and etching residue. Good etching characteristics are exhibited. On the other hand, when the content of phosphate salt exceeds the range of the present invention as in the case of Comparative Example 1, copper is not etched. Also, as in the case of Comparative Example 2, when the content of (NH ₄ ) ₂ S ₂ O ₈ exceeds the range of the present invention, the etching rate is greatly increased, and the wiring is lost due to the overeating angle.

FIG. 1B is a SEM photograph of a substrate on which a Cu single layer is deposited with the etchant composition of Example 2, FIG. 1B is a cross-sectional view of the etchant of FIG. This is a SEM photograph of the post-exposure period. Referring to FIGS. 1A and 1B, when the etchant composition according to an embodiment of the present invention is used, it can be confirmed that the pattern of copper is excellent and the damage of the bottom film does not occur.

FIG. 2A is an SEM image of a substrate on which a Cu / Mo double layer is deposited using the etching solution composition of Example 2, FIG. 2B is an SEM image of the substrate after the Cu / SEM photographs after peeling off the photoresist. Referring to FIGS. 2A and 2B, it can be seen that the galvanic phenomenon does not occur in the Cu / Mo bilayer, so that the pattern profile is excellent and the lower film damage does not occur.

FIG. 1A is an SEM photograph of a substrate on which a Cu single layer is deposited using the etching solution composition of Example 2. FIG.

FIG. 1B is an SEM photograph of a substrate on which a Cu single layer is deposited by using the etchant composition of Example 2 and etching the photoresist.

2A is an SEM photograph of a substrate on which a Cu / Mo double layer is deposited using the etching solution composition of Example 2. FIG.

FIG. 2B is a SEM photograph of a substrate on which a Cu / Mo double film is deposited using the etching solution composition of Example 2 and etching the photoresist. FIG.

Claims (12)

It contains no hydrogen peroxide, relative to the total composition weight, of 0.5 to 20 wt.% _{(NH 4) 2 S 2 O} 8; 0.1 to 5% by weight of a phosphate salt; 0.01 to 1% by weight of a fluorine-containing compound; 0.01 to 1% by weight of heterocyclic amine And at least one nitrogen compound selected from aminocarboxylic acid compounds; And 73 to 99.38% by weight of water. The etching solution composition according to claim 1, wherein the phosphate salt is at least one selected from the group consisting of salts in which hydrogen is substituted with 1 to 3 alkali metals or alkaline earth metals in phosphoric acid. The etching liquid composition according to claim 1, wherein the fluorinated compound is a compound capable of dissociating into fluorine ions or polyatomic fluorine ions. 4. The etchant composition according to claim 3, wherein the fluorine compound is at least one selected from the group consisting of ammonium fluoride, sodium fluoride, potassium fluoride, sodium bisulfite, and potassium bisphosphate. The method of claim 1, wherein the at least one nitrogen compound selected from the group consisting of the heterocyclic amine and the aminocarboxylic acid compound is selected from the group consisting of aminotetrazole, benzotriazole, imidazole, indole, But are not limited to, purine, pyrazole, pyridine, pyrimidine, pyrrole, pyrrolidine, pyrroline, alanine, aminobutyric acid Wherein the etching solution composition is at least one selected from the group consisting of glutamic acid, glycine, iminodiacetic acid, nitrilotriacetic acid, and sarcosine. The etchant composition of claim 1, wherein the water is deionized water. The etchant composition of claim 1, wherein the etchant composition further comprises at least one additive selected from an etch control agent, a surfactant, a sequestering agent, a corrosion inhibitor, and a pH adjuster. The etchant composition of claim 1, wherein the etchant composition is used to etch a first monolayer comprising copper, a second monolayer comprising molybdenum and multiple layers thereof. Forming one or more of a first monolayer comprising copper on the substrate, a second monolayer comprising molybdenum and multiple layers thereof; A method of forming a metal pattern, comprising etching one or more of the formed films with the etchant composition of any one of claims 1 to 8. [12] The method of claim 9, wherein the first single layer, the second single layer, and the multiple layer are formed using a vacuum evaporation method or a sputtering method. [12] The method of claim 9, further comprising forming a photoresist pattern on the formed film or films. [12] The method of claim 9, wherein in the etching step, the multiple layers are etched in a batch.

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