KR102281189B1 - Etching solution composition for copper-based metal layer and etching method using the same - Google Patents

Abstract

Based on the total weight of the composition, (a) persulfate 0.5 to 20% by weight, (b) 0.01 to 2% by weight of fluorine compound, (c) 1 to 10% by weight of inorganic acid, (d) 0.5 to cyclic amine compound 3% by weight, (e) 0.05 to 5% by weight of a sulfurized carboxylic acid compound, (f) 0.01 to 3% by weight of a copper compound, (g) 0.1 to 10% by weight of an organic acid or an organic acid salt, and (h) the balance of water It relates to a copper-based metal film etchant composition comprising the same and an etching method using the same.

Description

Copper-based metal layer etchant composition and etching method using the same {Etching solution composition for copper-based metal layer and etching method using the same}

The present invention relates to a copper-based metal film etchant composition and an etching method using the same.

In general, a thin film transistor (TFT) is used as a circuit board for independently driving each pixel in a liquid crystal display device or an organic EL (Electro Luminescence) display device. The thin film transistor array panel includes a scan signal line or gate line transmitting a scan signal, an image signal line or data line transmitting an image signal, and a thin film transistor connected to the gate line and the data line, and a thin film transistor connected to the thin film transistor. It consists of a pixel electrode and the like. When the thin film transistor array panel is manufactured, metal layers for gate wiring and data wiring are stacked on the substrate, and a process of etching these metal layers follows. The gate wiring and the data wiring use copper with good electrical conductivity and low resistance, but in the case of copper, there is a difficulty in the process of applying and patterning a photoresist, so the gate wiring and the data wiring do not apply a single copper film, Apply a multi-metal film. Among the multi-metal films, a titanium/copper double film is generally widely used. When the titanium/copper double layer is simultaneously etched, the etch profile is poor, and there is a difficulty in the subsequent process.

Korean Patent Laid-Open Patent No. 10-2012-0111636 discloses an etchant for etching a double layer of titanium/copper, persulfate 0.5 to 20% by weight, fluorine compound 0.01 to 2% by weight, inorganic acid 1 to 10% by weight, cyclic amine compound 0.5 to 5% by weight, 0.1 to 5% by weight of a chlorine compound, 0.05 to 3% by weight of a copper salt, 0.1 to 10% by weight of an organic acid or an organic acid salt, and water.

However, the etchant has a disadvantage in that the period for maintaining the etch performance is significantly shorter than that of the water-based system, the wiring open rate due to damage to the glass and photoresist is large, and the etchant management is difficult due to the precipitation of the etch reaction product.

Republic of Korea Patent Publication No. 10-2010-0090538

The present invention has been devised to solve the above problems of the prior art, and has excellent overall etching characteristics for a copper-based metal film, and in particular, prevents generation of poorly soluble copper ion precipitates, thereby causing wiring defects due to precipitation and process greatly improve cost, and prevent cost increase due to poorly soluble precipitates during waste liquid treatment; An object of the present invention is to provide a copper-based etchant composition that improves the wiring open rate due to damage to glass, insulating film, and photoresist.

Another object of the present invention is to provide a method for etching a copper-based metal film using the etching solution.

The present invention relates to (a) 0.5 to 20% by weight of a persulfate, (b) 0.01 to 2% by weight of a fluorine compound, (c) 1 to 10% by weight of an inorganic acid, (d) 0.5 to 3% by weight of a cyclic amine compound, (e) ) A copper-based metal film comprising 0.05 to 5% by weight of a sulfurized carboxylic acid compound, (f) 0.01 to 3% by weight of a copper compound, (g) 0.1 to 10% by weight of an organic acid or an organic acid salt, and (h) the remainder of water An etchant composition is provided.

Also, the present invention

(a) forming a copper-based metal film on a substrate;

(b) selectively leaving a photoreactive material on the copper-based metal layer; and

(c) etching the copper-based metal layer using the composition of the present invention; provides an etching method comprising a.

The etchant composition of the present invention prevents the generation of poorly soluble copper ion precipitates, thereby greatly improving the overall etching characteristics, as well as wiring defects due to precipitation and process costs due to cleaning of etching equipment, and cost increase due to poorly soluble precipitates during waste liquid treatment prevent; It provides the effect of improving the wiring open rate due to damage to glass, insulating film, and photoresist.

In addition, the etching method of the copper-based metal layer using the etchant provides a method of efficiently etching a gate electrode, a gate wiring, a source/drain electrode, and a data wiring.

1 is a photograph taken of the results of a precipitation experiment using the etchant composition of Example 1 and Comparative Example 2 of the present invention.
2 is an SEM image of the result of etching using the etchant composition of Example 1 and Comparative Example 2 of the present invention.

Based on the total weight of the composition, (a) persulfate 0.5 to 20% by weight, (b) 0.01 to 2% by weight of fluorine compound, (c) 1 to 10% by weight of inorganic acid, (d) 0.5 to cyclic amine compound 3% by weight, (e) 0.05 to 5% by weight of a sulfurized carboxylic acid compound, (f) 0.01 to 3% by weight of a copper compound, (g) 0.1 to 10% by weight of an organic acid or an organic acid salt, and (h) the balance of water It relates to a copper-based metal film etchant composition comprising.

In the present invention, the copper-based metal film includes copper as a component of the film, and is a concept including a single film and a multilayer film such as a double film.

For example, a single film of a copper film or a copper alloy film; or

a copper/titanium film including a titanium layer and a copper layer formed on the titanium layer, a copper/titanium alloy film including a titanium alloy layer and a copper layer formed on the titanium alloy layer;

a copper/molybdenum film including a molybdenum layer and a copper layer formed on the molybdenum layer, a copper/molybdenum alloy film including a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer;

A molybdenum/copper/molybdenum film including a copper layer formed between the upper molybdenum layer and the lower molybdenum layer, or a multilayer film of a molybdenum alloy/copper/molybdenum alloy film including a copper layer formed between the upper molybdenum alloy layer and the lower molybdenum alloy layer, etc. This is included.

The alloy film is a concept including a nitride film or an oxide film, and the molybdenum alloy layer is selected from the group consisting of, for example, titanium (Ti), tantalum (Ta), chromium (Cr), nickel (Ni) and neodymium (Nd). means an alloy of molybdenum with one or more being.

In particular, the copper-based metal film etchant composition of the present invention may be preferably applied to a multilayer film made of a copper or copper alloy film/titanium or titanium alloy film.

The visual solution of the present invention may also be used for a molybdenum-based metal film or a titanium-based metal film. The molybdenum-based metal film or the titanium-based metal film includes molybdenum or titanium as a component of the film, and is a concept including a single film and a multilayer film such as a double film.

The etchant composition of the present invention is characterized in that it does not contain a chlorine compound that causes poorly soluble copper ion precipitates. The chlorine compound is combined with a cyclic amine compound, a copper ion, and the like to generate a poorly soluble precipitate.

The persulfate (a) is a main component for etching the copper-based metal film, and is preferably included in an amount of 5 to 20 wt% based on the total weight of the composition. When the persulfate content is less than 0.5 wt%, the copper-based metal film cannot be etched or the etching rate is very slow, and when it exceeds 20 wt%, it becomes difficult to control the process because the etching rate is overall faster.

As the persulfate, potassium persulfate (K ₂ S ₂ O ₈ ), sodium persulfate (Na ₂ S ₂ O ₈ ), and ammonium persulfate ((NH ₄ ) ₂ S ₂ O ₈ ) 1 selected from the group consisting of More than one species may be used.

The (b) fluorine compound is a main component for etching the titanium-based metal film, and serves to remove residues that may be generated during etching.

The fluorine compound is preferably included in an amount of 0.01 to 2% by weight based on the total weight of the composition. When the fluorine compound is contained in an amount of less than 0.01 wt %, the etching rate of the titanium-based metal film may be lowered and residues may be generated, and if it exceeds 2.0 wt %, it is formed together with a substrate such as glass on which metal wiring is formed and metal wiring. It may cause damage to the insulating film containing silicon.

As the fluorine compound, a compound in which fluorine ions or polyatomic fluorine ions are dissociated in a solution may be used, and ammonium fluoride, sodium fluoride, potassium fluoride, and ammonium bifluoride may be used. ), sodium bifluoride (sodium bifluoride), and potassium bifluoride (potassium bifluoride) at least one selected from the group consisting of may be used.

The (c) inorganic acid is used as an auxiliary oxidizing agent for etching the copper-based metal film and the titanium-based metal film.

The inorganic acid is preferably included in an amount of 1 to 10% by weight based on the total weight of the composition, and when it is included in an amount of less than 1% by weight, the etching rate of the copper-based metal film and the titanium-based metal film is lowered, resulting in poor etching profile and residue. may occur, and when the content exceeds 10% by weight, over-etching and photoresist cracks may occur, and wiring may be short-circuited due to penetration of the chemical.

At least one selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid and perchloric acid may be used as the inorganic acid.

The (d) cyclic amine compound serves to control the etching rate of the copper-based metal layer.

The cyclic amine compound is preferably included in an amount of 0.5 to 3% by weight based on the total weight of the composition. When the cyclic amine compound is included in less than 0.5 wt%, it is impossible to control the etching rate of copper, so overetching may occur, and when it is included in excess of 3 wt%, the etching rate of copper is lowered and the process As the etching time increases, productivity may decrease.

Examples of the cyclic amine compound include 5-aminotetrazole, imidazole, indole, purine, pyrazole, pyridine, pyrimidine, and pyrrole. (pyrrole), pyrrolidine (pyrrolidine), and at least one selected from the group consisting of pyrroline (pyrroline) may be used.

The (e) sulfurized carboxylic acid compound serves as an auxiliary oxidizing agent for etching the copper-based metal film, as an agent for adjusting the angle of taper, and as an inhibitor for wiring opening that reduces yield.

The sulfurized carboxylic acid compound may be included in an amount of 0.05 to 5 wt%, more preferably 1 to 3 wt%, based on the total weight of the composition. When the sulfurized carboxylic acid compound is contained in an amount of less than 0.05 wt%, the etching rate of the copper-based metal film is lowered and the etching profile is poor. can

The sulfurized carboxylic acid compound is composed of mercapto propionic acid, cysteine 3,3'-thio propionic acid, and dithio dipropionic acid. One or more selected from the group may be used.

The (f) copper compound serves to control CD skew. The copper compound may be included in an amount of 0.01 to 3% by weight based on the total weight of the composition. When the content of the copper compound is less than 0.01% by weight, the initial etching becomes non-uniform, and when it exceeds 3% by weight, the etching performance is deteriorated.

The copper compound may be at least one selected from the group consisting of copper nitrate (Cu(NO ₃ ) ₂ ), copper sulfate (CuSO ₄ ), and copper ammonium phosphate (NH ₄ CuPO _{4 ).}

The (g) organic acid or organic acid salt forms chelation with the etched metal ions to prevent the etched metal ions from affecting the etchant, and consequently serves to increase the number of substrates to be treated.

The organic acid or organic acid salt is preferably included in an amount of 0.1 to 10% by weight based on the total weight of the composition. When the organic acid or organic acid salt is contained in an amount of less than 1% by weight, the effect of increasing the number of treatments cannot be expected, and even if it exceeds 10% by weight, the effect of increasing the number of treatments is no longer increased.

Examples of the organic acid or organic acid salt include acetic acid, butanoic acid, citric acid, formic acid, gluconic acid, glycolic acid, malonic acid, oxalic acid, pentanoic acid, sulfobenzoic acid, sulfosuccinic acid, sulfophthalic acid, salicylic acid, sulfosalicylic acid, benzoic acid, lactic acid, and glycolic acid. At least one selected from the group consisting of seric acid, succinic acid, malic acid, tartaric acid, isocitric acid, propenoic acid, iminodiacetic acid and ethylenediaminetetraacetic acid (EDTA) and their sodium, potassium, and ammonium salts may be used. .

(h) The water refers to deionized water and is used for semiconductor processing, and preferably 18㏁/cm or more water is used. The water is included in the remaining amount so as to be 100% by weight based on the total weight of the composition.

In addition, the etchant composition of the present invention may further include additives such as a metal ion sequestrant and a corrosion inhibitor in addition to the above components. In addition, in order to further improve the effect of the present invention, various other additives known in the art may be optionally added.

The components of the etchant composition of the present invention can be prepared by conventionally known methods, and it is preferable to use them in a purity for a semiconductor process.

In addition, the etchant composition of the present invention may be used not only for manufacturing a flat panel display such as a liquid crystal display, but also for manufacturing a memory semiconductor panel.

The etchant composition according to the present invention can efficiently etch the source/drain electrodes and data lines of the liquid crystal display formed of the copper-based metal film.

Also, the present invention

(a) forming a copper-based metal film on a substrate;

(b) selectively leaving a photoreactive material on the copper-based metal layer; and

(c) etching the copper-based metal layer using the etchant composition of the present invention; relates to an etching method comprising a.

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

In the above definition of the copper-based metal film, the above description is applied in the same way.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are provided to illustrate the present invention in more detail, and the scope of the present invention is not limited by the following examples. The following examples can be appropriately modified and changed by those skilled in the art within the scope of the present invention.

Example 1 to 4 and comparative example 1 to 4: copper-based etchant Composition preparation and characterization

(1) copper-based metal film etchant Preparation of the composition

The etchant compositions of Examples 1 to 4 and Comparative Examples 1 to 4 were prepared according to the compositions shown in Table 1, and the remaining amount of water was included so as to be 100% by weight.

(2) etchant Evaluation of the properties of the composition

Etching properties were evaluated using the etchant compositions of Examples 1 to 4 and Comparative Examples 1 to 4 as follows.

A SiNx layer was deposited on the glass, a titanium film was laminated on the SiNx layer, and a copper film was laminated on the titanium film. A photoresist was patterned in a predetermined shape on the copper film. The glass substrate was cut to 550×650 mm using a diamond knife to prepare a specimen.

The etchants of Examples 1 to 4 and Comparative Examples 1 to 4 were put into the experimental equipment of the spray-type etching method, and the temperature was heated to 25°C. Then, after the temperature reached 30±0.1° C., an etching process was performed. After inserting the specimen, spraying the etchant, and cleaning the specimen with deionized water when the etching was completed, the specimen was dried using a hot air drying device, and the etching characteristics were evaluated using an electron scanning microscope.

The presence or absence of formation of precipitates was checked under harsh conditions for storage and processing. That is, 3000 ppm of copper powder was mixed in the etchant, and the presence or absence of poorly soluble precipitates was checked while stored at -8 °C.

The evaluation results are shown in Table 1 and FIGS. 1 and 2 below.

SPS ABF HNO ₃ ATZ NaCl Mercapto
propionic acid CuSO ₄ AcOH Precipitation Occurrence Cu/Ti film open
existence and nonexistence Cu/Ti
etching
Degree Example 1 10 0.5 3 1.5 - 0.1 0.2 3 No precipitation non-occurring clear Example 2 10 0.5 3 1.5 - One 0.2 3 No precipitation non-occurring clear Example 3 10 0.5 3 1.5 - 3 0.2 3 No precipitation non-occurring clear Example 4 10 0.5 3 1.5 - 5 0.2 3 No precipitation non-occurring clear Comparative Example 1 10 0.5 3 1.5 0 0 0.2 3 No precipitation Open occurs Etching rate is slow Comparative Example 2 10 0.5 3 1.5 1.5 0 0.2 3 1st day of precipitation non-occurring clear Comparative Example 3 10 0.5 3 1.5 1.5 1.5 0.2 3 1st day of precipitation non-occurring clear Comparative Example 4 10 0.5 3 1.5 0 7 0.2 3 No precipitation non-occurring over-etched

(Unit: % by weight)

main)

SPS: Sodium persulfate

ABF: Ammonium bifluoride

ATZ: 5-aminotetrazole

AcOH: Acetic acid

CuSO ₄ : Copper Sulfate

As shown in Table 1, in the etchant compositions of Examples 1 to 4 of the present invention that contain a sulfurized carboxylic acid compound and do not contain a chlorine compound, a problematic precipitate is generated in the etchant as shown in FIG. 1 . and, as shown in FIG. 2 , it was confirmed that the etching performance was also excellent.

On the other hand, in the etchant compositions of Comparative Examples 2 and 3 including the chlorine compound, precipitates were generated as shown in FIG. 1 . In the case of the etchant composition of Comparative Example 1, the copper film was opened because neither the sulfurized carboxylic acid compound nor the chlorine compound was included. In the case of the etchant composition of Comparative Example 4, no precipitate was generated by including an excess of the sulfurized carboxylic acid compound, but overetching occurred.

Claims (12)

Based on the total weight of the composition, (a) persulfate 0.5 to 20% by weight, (b) 0.01 to 2% by weight of a fluorine compound, (c) 1 to 10% by weight of an inorganic acid, (d) 0.5 to 3% by weight of a cyclic amine compound , (e) 0.05 to 5% by weight of a sulfurized carboxylic acid compound, (f) 0.01 to 3% by weight of a copper compound, (g) 0.1 to 10% by weight of an organic acid or an organic acid salt, and (h) the balance of water;
The (e) sulfurized carboxylic acid compound is mercapto propionic acid, cysteine 3,3'-thio propionic acid, and dithio dipropionic acid. Including at least one selected from the group consisting of,
Copper-based metal film etchant composition, characterized in that it does not contain a chlorine compound. The copper-based metal film etchant composition according to claim 1, wherein the (a) persulfate comprises at least one selected from the group consisting of potassium persulfate, sodium persulfate and ammonium persulfate. The method according to claim 1, wherein the fluorine compound is ammonium fluoride, sodium fluoride, potassium fluoride, ammonium bifluoride, sodium bifluoride, and copper-based characterized in that it comprises at least one selected from the group consisting of potassium bifluoride. A metal film etchant composition. The copper-based metal film etchant composition according to claim 1, wherein (c) the inorganic acid comprises at least one selected from the group consisting of nitric acid, sulfuric acid, phosphoric acid and perchloric acid. The method according to claim 1, wherein (d) the cyclic amine compound is 5-aminotetrazole, imidazole, indole, purine, pyrazole, pyridine, A copper-based metal film etchant composition comprising at least one selected from the group consisting of pyrimidine, pyrrole, pyrrolidine, and pyrroline. delete The method according to claim 1, wherein the (f) copper compound is copper nitrate (Cu(NO ₃ ) ₂ ), copper sulfate (CuSO ₄ ), and copper ammonium phosphate (NH ₄ CuPO ₄ ) comprising at least one selected from the group consisting of Copper-based metal film etchant composition, characterized in that. The method according to claim 1, wherein (g) the organic acid is acetic acid, butanoic acid, citric acid, formic acid, gluconic acid, glycolic acid, malonic acid, oxalic acid, pentanoic acid, sulfobenzoic acid, sulfosuccinic acid, sulfophthalic acid, salicylic acid, sulfosalicylic acid, benzoic acid , lactic acid, glyceric acid, succinic acid, malic acid, tartaric acid, isocitric acid, propenoic acid, iminodiacetic acid, and at least one selected from the group consisting of ethylenediaminetetraacetic acid;
The organic acid salt is a copper-based metal film etchant composition comprising at least one selected from the group consisting of potassium salt, sodium salt and ammonium salt of the organic acid. The method according to claim 1, wherein the copper-based metal film is a single film of a copper film or a copper alloy film; or
a copper/titanium film including a titanium layer and a copper layer formed on the titanium layer, a copper/titanium alloy film including a titanium alloy layer and a copper layer formed on the titanium alloy layer;
a copper/molybdenum film including a molybdenum layer and a copper layer formed on the molybdenum layer, a copper/molybdenum alloy film including a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer;
A molybdenum/copper/molybdenum alloy film including a molybdenum/copper/molybdenum film comprising a copper layer formed between the upper molybdenum layer and the lower molybdenum layer, or a copper layer formed between the upper molybdenum alloy layer and the lower molybdenum alloy layer; phosphorus; Copper-based metal film etchant composition, characterized in that. (a) forming a copper-based metal film on a substrate;
(b) selectively leaving a photoreactive material on the copper-based metal layer; and
(c) etching the copper-based metal film using the composition of any one of claims 1 to 5 and 7 to 9; an etching method comprising a. The method according to claim 10, wherein the copper-based metal film is a single film of a copper film or a copper alloy film; or
a copper/titanium film including a titanium layer and a copper layer formed on the titanium layer, a copper/titanium alloy film including a titanium alloy layer and a copper layer formed on the titanium alloy layer;
a copper/molybdenum film including a molybdenum layer and a copper layer formed on the molybdenum layer, a copper/molybdenum alloy film including a molybdenum alloy layer and a copper layer formed on the molybdenum alloy layer;
A molybdenum/copper/molybdenum alloy film including a molybdenum/copper/molybdenum film comprising a copper layer formed between the upper molybdenum layer and the lower molybdenum layer, or a copper layer formed between the upper molybdenum alloy layer and the lower molybdenum alloy layer; phosphorus; An etching method of a copper-based metal film, characterized in that. The method of claim 10 , wherein the photoreactive material is a photoresist material and is selectively left by an exposure and development process.

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