WO2006011747A1

WO2006011747A1 - Aqueous resist stripper composition

Info

Publication number: WO2006011747A1
Application number: PCT/KR2005/002429
Authority: WO
Inventors: Kwang-Yong Lee; Woong Kim; Hyuk-Jin Cha; Won-Su Byeon; Yong-Man Jeong; Choul-Kyu Lim; Nak-Chil Jung
Original assignee: Samyangems Co., Ltd.
Priority date: 2004-07-28
Filing date: 2005-07-26
Publication date: 2006-02-02
Also published as: KR100629416B1; TW200613543A; KR20060010366A; TWI311585B

Abstract

Aqueous resist stripper composition capable of stripping a resist from a resist-coated substrate such as a color filter substrate or a TFT substrate is disclosed. The aqueous resist stripper composition according to the present invention includes 0.3 to 15 % by weight of an inorganic alkaline compound; 0.1 to 12 % by weight of a tetraalkylammonium hydroxide compound; 0.1 to 40 % by weight of a water-soluble organic solvent; and 33 to 99.5 % by weight of water, based on a total weight of the composition. The aqueous resist stripper composition according to the present invention may be useful to easily and simply remove a variety of resists which are generated during the process of manufacturing TFT-LCD but not easily removed by the con¬ ventional methods, as well as to minimize corrosions of a lower metal layer and a glass substrate during the stripping process, maximize a replacement cycle of the stripper due to its low loss by evaporation and its low aging, and regenerate the color substrate and the TFT substrate at a large scale.

Description

AQUEOUS RESIST STRIPPER COMPOSITION

Technical Field

[1] The present invention relates to aqueous resist stripper composition capable of removing a cured resist, and more particularly to aqueous resist stripper composition capable of being used to regenerate a substrate by stripping a resist from a resist-coated substrate such as a color filter substrate or a TFT substrate. Background Art

[2] Generally, a color TFT-LCD is manufactured in several steps of forming, on a transparent substrate such as a glass, a color filter forming a black matrix resin and a pixel consisting of red (R), green (G) and blue (B); forming on the color filter a transparent conducting film as an electrode using a sputtering method; forming an alignment layer on the transparent conducting film; and filling a liquid crystal into the LCD.

[3] The resist has been widely used to form patterns of the color TFT-LCD such as an overcoat, a photo spacer, a color filter, a black matrix, etc. However, it is impossible to remove only resists with an incorrect pattern from the substrate when the resist is cured by light or heat. In particular, it was very difficult to remove the various resists such as an epoxy-based, epoxy acrylate-based, acrylate-based UV overcoat and a thermal overcoat, a photo spacer resist, a color filter resist, a black matrix resin and resists used in IPA and MVA modes. As describe above, the conventional resist stripper composition has a problem that a poor color filter substrate or a poor TFT substrate with the incorrect pattern is wasted without undergoing regeneration processes such as a repair and regeneration due to absence of solvents for effectively removing a large quantity of the cured resist from the substrate.

[4] In order to solve the above object, there has been attempted various studies. In

U.S.A. Patent No. 5,059,500, it was disclosed that some of a cured color resist was removed under the conditions of a vacuum of 10 Dtorr and an operating current of 50 W using a plasma. But the method using the plasma has a disadvantage of using a high vacuum, a high power, toxic gases and expensive equipment.

[5] In U.S.A. Patent No. 5,756,239, it was disclosed that some of a cured color resist was removed on a small scale, but the method was not suitable to apply to a large-scale glass substrate.

[6] U.S.A. Patent Nos. 5,091,103, 5,308,745, 5,102,777, 5,597,678 disclose a resist stripper including N-methylpyrrolidone, alkylene glycol ether and l,3-dimethyl-2-imidazolidinone for stripping a cross-linked photoresist film. However, the stripper has a problem that it shows an insufficient solubility to remove the color filter resist.

[7] Korean Patent Publication No. 2003-2664 discloses aqueous stripper composition for a color filter including (a) the group consisting of inorganic alkaline hydroxide, alkylammonium hydroxide, alkylarylammonium hydroxide, (b) alkylene glycol ether, (c) aqueous amine compound, and (d) water. However, the aqueous stripper has a problem that a working time increases in the re- work process since a stripping rate is slow for a thermal overcoat. Disclosure of Invention Technical Problem

[8] Accordingly, the present invention is designed to solve the problems of the prior art, and therefore it is an object of the present invention to provide aqueous resist stripper composition for easily and simply removing a variety of resists which are generated during the process of manufacturing TFT-LCD but not easily removed by the con¬ ventional methods, the resists selected from the group consisting of an epoxy-based, epoxy acrylate-based, acrylate-based UV overcoat and a thermal overcoat, a photo spacer resist, a color filter resist, a black matrix resin and resists used in IPA and MVA modes, as well as minimizing corrosions of the lower metal layer and the glass substrate during the stripping process, maximizing a replacement cycle of the stripper due to its low evaporative loss and its high stripping speed for regenerating the color substrate and the TFT substrate at a large scale. Technical Solution

[9] In order to accomplish the above object, the present invention provides aqueous resist stripper composition comprising 0.3 to 15 % by weight of an inorganic alkaline compound; 0.1 to 12 % by weight of a tetraalkylammonium hydroxide compound; 0.1 to 40 % by weight of a water-soluble organic solvent; and 33 to 99.5 % by weight of water, based on total weight of the composition. Best Mode for Carrying Out the Invention

[10] Hereinafter, preferred embodiments of the present invention will be described in detail.

[11] The aqueous resist stripper composition according to the present invention includes an inorganic alkaline compound. The inorganic alkaline compound functions to easily remove a resist from a glass surface by weakening a binding force between binder components and/or cured poly-functional monomers composed of the resist composition. An example of the inorganic alkaline compound may include, but is not limited to, sodium carbonate, potassium carbonate, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, etc. if it functions as described previously. Especially it is preferred to use sodium hydroxide or potassium hydroxide.

[12] In the present invention, the inorganic alkaline compound has a content of 0.3 to 15

% by weight, based on a total weight of the stripper composition of the present invention. The inorganic alkaline compound has a problem of showing a poor stripping property if it has a content of less than 0.3 % by weight, while it has a problem of depositing an organic salt and an inorganic alkaline compound into a solid due to evaporation of moisture and an organic solvent during the stripping process, and therefore resulting in a severe damage to the glass substrate if it exceeds a content of 15 % by weight. The inorganic alkaline compound preferably has a content of 1 to 7 % by weight.

[13] A tetraalkylammonium hydroxide compound, which is included in the aqueous resist stripper composition of the present invention, is represented by Chemistry Figure 1, as follows.

[14] Chemistry Figure 1

R i I

R₂ - N⁺- R4OH

R₃

[15] wherein R to R is independently a substituted alkyl group or an unsubstituted alkyl group. The unsubstituted alkyl group includes an alkyl group having 1 to 4 carbon atoms selected from the group consisting of a methyl group, an ethyl group, an n- propyl group, an n-butyl group, etc. Also, the substituted alkyl group is preferably an alkyl group where a hydrogen atom of the alkyl group having 1 to 4 carbon atoms is substituted with a hydroxy group, an alkoxy group or a hydroxyalkyl group, and an example of the substituted alkyl group includes a 2-hydroxy ethyl group, a 3-hydroxy propyl group, a 4-hydroxy butyl group, a 2-methoxyethyl group, a 2-(2-hydroxyethoxy)ethyl group, etc. An example of Such a tetraalkylammonium hydroxide compound includes tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra n-propylammoniumhydroxide, tetra n-butylammonium hydroxide, tetra(2-hydroxyethyl)ammonium hydroxide, trimethyl(2-hydroxyethyl)ammonium hydroxide, trimethyl2-(2-hydroxyethoxy)ethylammonium hydroxide, dimethyldiethy- lammonium hydroxide, etc. The compounds may be used alone or with a mixture thereof.

[16] The tetraalkylammonium hydroxide compound, which mainly functions to remove the color resists of R, G and B from the color filter substrate, has a content of 0.1 to 12 % by weight and preferably 0.1 to 8 % by weight, based on a total weight of the aqueous resist stripper composition of the present invention. The tetraalkylammonium hydroxide compound has a poor stripping property of the resist if it has a content of less than 0.1 % by weight, while the tetraalkylammonium hydroxide compound has an advantage of easily stripping the resist, but a disadvantage of causing corrosion of the glass substrate if it exceeds a content of 12 % by weight.

[17] The aqueous resist stripper composition of the present invention includes a water- soluble organic solvent. The water-soluble organic solvent allows a cured portion to be effectively stripped from the substrate by swelling only the cured portion of the resist components, and especially it is effective to remove the thermal overcoat.

[18] The water-soluble organic solvent includes amides such as dimethylsulf oxide; N- methyl-2-pyrrolidinone, N-ethyl-2-pyrrolidinone, N-propyl-2-pyrrolidinone, N- hydroxymethyl-2-pyrrolidinone, N-hydroxyethyl-2-pyrrolidinone, N- methylformamide, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N,N-diethylacetamide, etc.; sulfones such as dimethylsulf one, diethylsulfone, bis(2-hydroxyethyl)sulfone, tetramethylenesulfone, etc.; alcohols such as methylalcohol, ethylalcohol, propylalcohol, butylalcohol, pentylalcohol, hexylalcohol, isopropylalcohol, isobutylalcohol, etc. and derivatives thereof. They may be used alone or with a mixture thereof.

[19] Such a water-soluble organic solvent has a content of 0.1 to 40 % by weight, and preferably 1 to 30 % by weight, based on a total weight of the aqueous stripper composition. The water-soluble organic solvent shows a poor swelling effect on the resist and therefore a poor stripping property if it has a content of less than 0.1 % by weight, while the water-soluble organic solvent shows an excellent swelling effect on the resist if it exceeds a content of 40 % by weight, but shows a poor stripping property as its duration of use increases since the stability of the composition is lowered.

[20] In the aqueous resist stripper composition of the present invention, water may be used as a solvent since it is an environment-friendly solvent and shows improved properties such as stability and a stripping property against flammability. Water used in the aqueous resist stripper composition of the present invention may preferably be a pure water or ultra pure water such as ion-exchanged water, distilled water, etc, and it has a content of 33 to 99.5 % by weight, based on the composition of the present invention.

[21] Meanwhile, an amine compound or an alkylene glycol-based organic solvent may further be added to improve the stripping property of the aqueous resist stripper composition according to the present invention. The amine compound preferably has a negative logarithm of the acid dissociation constant (pH) of 7.5 to 13.5 in the aqueous solution at 25 ⁰C, considered to the corrosivity by Ti and Al. An example of such an amine compound includes alkanol amines such as hydroxylamine, monoethanolamine, diethanolamine, triethanolamine, 2-(2-aminoethoxy)ethanol, N,N-dimethylethylamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N-methylethanolamine, N- ethylethanolamine, N-butylethanolamine, N-methyldiethanolamine, monoiso- propanolamine, triisopropanolamine, etc.; polyalkylene polyamines such as diethylen- etriamine, triethylenetetraamine, propylenediamine, N,N-diethylethylenediamine, N,N'-diethylethylenediamine, 1 ,4-butanediamine, N-ethyl-ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,6-hexanediamide, etc.; aliphatic amines such as 2-ethyl-hexylamine, dioctylamine, tributylamine, tripropylamine, heptylamine, cyclohexyl amine, etc.; aromatic amines such as benzylamine, diphenylamine, etc.; cylic amines such as piperazine, N-methyl-piperazine, methyl-piperazine, hydrox- ylethylpiperazine, etc. Especially monoethanolamine, 2-(2-aminoethoxy)ethanol, di- ethylenetriamine, triethylenetetraamine, cyclohexylamine and piperazine may preferably be used out of the above mentiond compounds. The amine compound may have a content of 1 to 30 % by weight considered to its stability and stripping property, based on a total weight of the composition.

[22] In addition, an example of the alkylene glycol-based organic solvent includes, but is not limited to, an organic solvent of carbitols such as methylcarbitol, ethylcarbitol, butyl carbitol; a glycol organic solvent of polyhydric alcohols such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, ethyleneglyco- lethyletheracetate, diethyleneglycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether; and derivatives thereof. They may be used alone or with a mixture thereof. The alkylene glycol-based organic solvent may have a content of 1 to 45 % by weight considered to its stripping property and compatability with water, based on a total weight of the composition.

[23] Also, a surfactant may be added to remove the resist components in a more effective manner. The surfactant functions to lower an interaction between the resist film and a glass substrate, and therefore reduce a surface energy to penetrate an alkaline compound and an organic solvent into a resist paint film, finally giving an excellent stripping property to the glass substrate. In addition, the surfactant may prevent the stripped resist components from being reattached to the glass substrate, and also prevent the aqueous stripper from being decolored due to its oxidation even when it is used for a long time. The surfactant is not limited if it may be used in the aqueous resist stripper. For example, the surfactant includes a sulfoxide -based or carboxy-based cationic surfactant such as alkylbenzene sulfonate, alkylsulfate, poly- oxyalkylethersulfate, alkansulfonate, polyoxyethylene alkylether methylcarboxylate, alkylphosphate, alkylsulfosuccinate, olefinsulfonate, aceylamidoalkyl sulfate, aceyl- sarcosinate, sodium naphthalene sulfonate formalin condensate, etc., or a non-ionic surfactant having 5 to 20 % by weight of an ethylene oxide adduct, and they may be used alone or with a mixture thereof. The surfactant preferably has a content of 0.05 to 10 % by weight considered to an effect on its addition and a washing property after treatment of the aqueous stripper, based on a total weight of the composition.

[24] The aqueous resist stripper composition according to the present invention shows an excellent stripping property, a very low corrosivity of the lower substrate, and a low evaporation and aging properties. The aqueous stripper composition also allows mass- production of the glass substrate due to a low environmental pollution and working stability in the field because water is used as a solvent in the composition, as described previously. Accordingly, unlike the conventional color filter or TFT substrates which have been wasted due to the incorrect pattern formation, the color filter or TFT substrates obtained from the aqueous resist stripper composition according to the present invention may effectively remove a variety of the resists present in large areas of the color filter substrate and the TFT substrate, and therefore regenerate the color substrate and the TFT substrate. Mode for the Invention

[25] Hereinafter, preferred embodiments of the present invention will be described in detail referring to the accompanying drawings. Prior to the description, it should be understood that the terms used in the specification and appended claims should not be construed as limited to general and dictionary meanings, but interpreted based on the meanings and concepts corresponding to technical aspects of the present invention on the basis of the principle that the inventor is allowed to define terms appropriately for the best explanation. Therefore, the description proposed herein is just a preferable example for the purpose of illustrations only, not intended to limit the scope of the invention, so it should be understood that other equivalents and modifications could be made thereto without departing from the spirit and scope of the invention.

[26] Embodiments 1 to 16

[27] An inorganic alkaline compound, water, a tetraalkylammonium hydroxide compound and a water-soluble organic solvent were added to a bath equipped with a stirrer, based on the contents listed in Table 1. And the resultant mixture was stirred at room temperature for 0.5 to 3 hours at a rotating speed of 200 to 600 rpm to obtain aqueous stripper composition.

[28] Table 1

[29] Comparative embodiments 1 to 3 [30] Aqueous resist aqueous stripper compositions were prepared in the same manner as the Embodiments 1 to 16, based on the components and contents listed in a following Table 2.

[31] Table 2

[32] In the Tables 1 and 2, KOH represents potassium hydroxide, TMAH represents tetramethylammonium hydroxide, TEAH represents tetraethylmmonium hydroxide, TPAH represents tetrapropylammonium hydroxide, NMP represents N-methyl pyrrolidone, DMSO represents dimethyl sulfoxide, BzOH represents benzyl alcohol, BDG represents butyldiglycol, EC represents ethylcarbitol, HDA represents hydroxyl amine, MEA represents monoethanolamine, DMAC represents N,N-dimethylacetamide, DI represents an ultra pure water, K-290 represents cationic surfactant commercially available from the company Hannong Chemicals Inc., and OP-IO represents non-ionic surfactant commercially available from the company Hannong Chemicals Inc.

[33] The aqueous resist stripper compositions of the Embodiments and the Comparative embodiments prepared in the above mentioned manner were measured for a stripping property, corrosivity and evaporation rate, as follows.

[34] <Evaluation of a stripping property>

[35] Composition A is comprised of a black matrix resin, a color filter photoresist, a UV overcoat and a photo spacer resist, and Composition B is identical to the Composition A, except that a thermal overcoat was used instead of the UV overcoat. The Com¬ positions A and B were evaluated for their stripping properties. The aqueous stripper compositions prepared in the Embodiments and the Comparative embodiments were kept at 55 ⁰C, and then a stripping level of test samples were investigated at the time points of 10 minutes, 15 minutes and 20 minutes by an ultrasonic cleaning. The evaluation standard is as follows.

[36] © : Completely removed within 15 minutes.

[37] O : Completely removed within 15 to 20 minutes.

[38] x : Not removed after the time point of 20 minutes.

[39] <Evaluation of corrosivity>

[40] The test samples, which were used in the evaluation of a stripping property, were also used to carry out a corrosion test of the aqueous stripper composition. The aqueous stripper compositions prepared in the Embodiments and the Comparative em¬ bodiments were kept at 55 ⁰C, and the organic substrates treated with a Cr black matrix were immersed into the compositions for 25 minutes and then washed with DI. The Cr black matrix treated thus was removed with an etchant, and then a corrosion level of the glass substrate was evaluated by measuring deviations from a damaged portion and a remaining portion of Cr black matrix in the glass substrate.

[41] O : Nearly corroded in a Cr BM and a glass substrate.

[42] Δ : Corroded in some portion of a Cr BM and a glass substrate.

[43] x : Significantly corroded in a Cr BM and a glass substrate.

[44] <Evaluation of evaporation rate>

[45] The aqueous stripper was quantitified to 100 g in a glass beaker, and then weighed at one-hour intervals while keeping a temperature at 55 ⁰C. the weight was measured and recorded up to the time points of 6 hours, and then an evaporative loss was evaluated as a percentage, based on the weight recorded at the first onset.

[46] Accordingly, the results are listed in the following Table 3. [47] Table 3

Evaluation

Test

Stripping Evaporat ion sample corrosivity property rate (%)

Embodiment 1 11

Embodiment 2 O 10

Embodiment 3 O 11

Embodiment 4 O 10

Embodiment 5 O 10

Embodiment 6 O 11

Embodiment 7 O 10

Embodiment 8 O

Embodiment 9 O 11

Embodiment 10 11

Embodiment 11 O 10

Embodiment 12 O

Embodiment 13 O 10

Embodiment 14 O 10

Embodiment 15 O

Embodiment 16 O 10

Embodiment 1 O 11

Embodiment 2 O 10

Embodiment 3 O 11

Embodiment 4 O 10

Embodiment 5 10

Embodiment 6 O 11

Embodiment 7 10

Embodiment 8

Embodiment 9 O 11

Embodiment 10 O 11

Embodiment 11 O 10

Embodiment 12 O

Embodiment 13 O 10

Embodiment 14 Δ 10

Embodiment 15 O

Embodiment 16 O 10

Comparative embodiment 1 11

Comparative embodiment 2 12

Comparative embodiment 3 11

Comparative embodiment 1 Δ 11

Comparative embodiment 2 12

Comparative embodiment 3 11

[48] Referring to the Table 3, it is revealed that the aqueous resist stripper compositions (Embodiments 1 to 16) according to the present invention easily and completely remove the various resists such as a black matrix resin, a color filter resist, a UV overcoat, a photo spacer resist, a thermal overcoat, etc., as well as show a very low corrosivity.

[49] Meanwhile, it is revealed that the aqueous stripper compositions according to the

Comparative embodiments 1 to 3 show a poor stripping property and corrode the lower substrate.

Industrial Applicability

[50] As described above, the aqueous resist stripper composition of the present invention may be useful to easily and simply remove a variety of resists which are generated during the process of manufacturing TFT-LCD but not easily removed by the con¬ ventional methods, the resists selected from the group consisting of an epoxy-based, epoxy acrylate-based, acrylate-based UV overcoat and a thermal overcoat, a photo spacer resist, a color filter resist, a black matrix resin and resists used in IPA and MVA modes. In addition, the aqueous resist stripper composition of the present invention may be useful to minimize corrosions of the lower metal layer and the glass substrate during the stripping process, and to maximize a replacement cycle of the stripper due to its low evaporative loss and its high stripping speed for regenerating the color substrate and the TFT substrate at a large scale.

Claims

[1] Aqueous resist stripper composition, comprising 0.3 to 15 % by weight of an inorganic alkaline compound; 0.1 to 12 % by weight of a tetraalkylammonium hydroxide compound; 0.1 to 40 % by weight of a water-soluble organic solvent; and 33 to 99.5 % by weight of water, based on a total weight of the composition.

[2] The aqueous resist stripper composition according to the claim 1, wherein the inorganic alkaline compound is selected from the group consisting of sodium carbonate, potassium carbonate, sodium silicate, potassium silicate, sodium hydroxide and potassium hydroxide.

[3] The aqueous resist stripper composition according to the claim 1, wherein the tetraalkylammonium hydroxide compound is selected from the group consisting of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetra n-propylammonium hydroxide, tetra n-butylammonium hydroxide, tetra(2-hydroxy ethyl) ammonium hydroxide, trimethyl(2-hydroxyethyl)ammonium hydroxide, trimethyl2-(2-hydroxyethoxy)ethylammonium hydroxide and dimethyldiethy- lammonium hydroxide.

[4] The aqueous resist stripper composition according to the claim 1, wherein the water-soluble organic solvent is selected from the group consisting of dimethylsulfoxide, N-methyl-2-pyrrolidinone, N-ethyl-2-pyrrolidinone, N- propyl-2-pyrrolidinone, N-hydroxymethyl-2-pyrrolidinone, N-hy- droxyethyl-2-pyrrolidinone, N-methylformamide, N,N-dimethylformamide, N- methylacetamide, N,N-dimethylacetamide, N,N-diethylacetamide, dimethylsulfone, diethylsulfone, bis(2-hydroxyethyl)sulfone, tetramethyle- nesulfone, methylalcohol, ethylalcohol, propylalcohol, butylalcohol, pentylalcohol, hexylalcohol, isopropylalcohol, isobutylalcohol, and derivatives thereof.

[5] The aqueous resist stripper composition according to the claim 1, further comprising an amine compound.

[6] The aqueous resist stripper composition according to the claim 1, further comprising an alkylene glycol-based organic solvent.

[7] The aqueous resist stripper composition according to the claim 6, further comprising a surfactant.