KR20050050346A - Thinner for removing photoresist - Google Patents

Abstract

The present invention relates to a cleaning solution for removing the photoresist, based on the total weight of the composition 0.1 to 10% by weight of organic or inorganic alkali, 1 to 25% by weight of non-amine polar organic solvent, 0.01 to 5% by weight of zwitterionic surfactant and It provides a cleaning solution for removing a photoresist, characterized in that containing 60 to 95% by weight of ionized water. When the cleaning solution according to the present invention is used for edge bead removing, not only can the edge bead be effectively removed, but also no unnecessary residue is generated on the surface of the substrate after the removal.

Description

Cleaning solution for removing photoresist {THINNER FOR REMOVING PHOTORESIST}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning solution for removing photoresist, and more particularly, to a pigment dispersion type photoresist applied unevenly to the edge of a substrate in a color filter manufacturing process of a thin film transistor liquid crystal display (TFT LCD). The present invention relates to a cleaning solution for removing edge bead (hereinafter referred to as 'EBR').

The color filter manufacturing process of the liquid crystal display device manufacturing process is generally as follows. After depositing a metal layer such as chromium on an LCD glass substrate by a deposition process such as sputtering, the chromium is subjected to a photoresist coating process, an exposure process, a developing process, an etching process, a photoresist peeling process, and the like. Form a black matrix. Alternatively, a pigment dispersed black matrix photoresist may be used without using chromium. An organic black matrix is formed through a photoresist coating step, an exposure step, a developing step, and a thermosetting step. Applying a color resist to the substrate on which the black matrix is formed and repeating a series of photoresist coating, exposure, developing, and thermal curing processes three times as in the organic black matrix manufacturing process, the red, green ( Green and blue color resist patterns are formed to form a color filter. In this process, the pigment-dispersed photoresist is selectively exposed to light of a specific wavelength through a suitable mask to react. Then, in the developing process, the pigment-dispersed photoresist is removed only in the selected region (specifically, in the case of the pigment-dispersed photoresist, the unlighted portion is recorded in the developer), and the unmelted portion is further subjected to a subsequent heat curing process. Harden.

Pigment dispersion type photoresist is mainly applied by a spin coater. When pigment dispersion type photoresist is dropped through a supply nozzle in the center of the substrate, it spreads gradually toward the edge of the substrate by centrifugal force. During the application process, the solvent evaporates and the viscosity gradually increases, and a large amount of pigment-dispersed photoresist is accumulated at the edge of the substrate due to friction with the substrate. Edge beads are formed. Edge bead of such a pigment dispersion type photoresist can cause serious problems in the overall liquid crystal display manufacturing process. For example, the flatness of the substrate may be reduced to adversely affect processes such as focusing and alignment during exposure, and to contaminate expensive equipment such as exposure equipment. The same phenomenon occurs when the photoresist is applied on the wafer in the semiconductor integrated circuit fabrication process. In particular, since the pigment contained in the pigment dispersion resist may act as a particulate impurity in the color filter manufacturing process in manufacturing the liquid crystal display device, such edge beads cause defects such as scratches in the alignment layer manufacturing process, which is desirable for the liquid crystal array. It may not have the effect.

In order to remove the edge bead, which is the cause of the above problems, conventionally, in the process of manufacturing semiconductor integrated circuits and liquid crystal displays, ethyl cellosolve acetate (ECA) and methylmethoxy propionate (MMP) are mainly used. And single solvents such as ethyl lactate (EL) have been widely used. However, ethyl cellosolve acetate has a problem in use because it has a limitation in economics and performance of methyl methoxy propionate and ethyl lactate due to human harmfulness. In order to solve this problem, a conventional method of mixing and using a single solvent has been developed. As such a mixed thinner composition, a mixture of propylene glycol alkyl ether, butyl acetate and ethyl lactate, or butyl acetate, ethyl lactate, and propylene Thinner composition consisting of a mixture of glycol alkyl ether acetates (JP-A-7-128867), a mixture of propylene glycol alkyl ether propionate and methyl ethyl ketone, or a mixture of propylene glycol alkyl ether propionate and butyl acetate Thinner composition (Japanese Patent Publication No. 7-160008), thinner composition (US Pat. No. 4,983,490) consisting of a mixture of propylene glycol alkyl ether acetate and propylene glycol alkyl ether, and a mixture of ethyl lactate and propylene glycol alkyl ether Thinner composition (US patent 4,886,728). However, the organic solvents are not suitable for removing the edge bead of the pigment dispersed photoresist containing the pigment. When the edge beads of the pigment-dispersion type photoresist are removed with an organic solvent, the binder or resin in the photoresist component may be easily dissolved, but the pigment may not be sufficiently melted. In general, there is a problem in that only the pigments that are not dissolved well remain.

In order to solve the above problems, the edge bead removal liquid composition (US Pat. No. 6,015,467), hydroxide, consisting of a mixture of an aqueous alkali solution containing an alkanolamine or tetraammonium salt and an alcohol, glycol ether or aprotic solvent, which is a water-soluble organic solvent. EBR cleaning solution containing alkali metals, amines and surfactants (Korean Patent Publication No. 2002-0063096), alcohols, amines, surfactants and deionized water (Korean Patent Publication No. 2002-0094164) , EBR cleaning solution containing organic or inorganic alkali, organic solvent, nonionic surfactant and deionized water (Korean Patent Publication No. 2003-0043190) have been proposed, but problems of removal and reattachment of various types of pigment dispersion resists Not enough performance to solve it.

Accordingly, an object of the present invention is to provide a new cleaning solution for removing photoresist that can quickly and effectively remove unnecessary resist formed on an edge portion on a substrate in a liquid crystal display manufacturing process.

In order to achieve the above object, the present invention is 0.1 to 10% by weight of organic or inorganic alkali, 1 to 25% by weight of non-amine polar organic solvent, 0.01 to 5% by weight of zwitterionic surfactant and deionized water based on the total weight of the composition It provides a cleaning solution for removing a photoresist, characterized in that it comprises 60 to 95% by weight.

Hereinafter, the present invention will be described in more detail.

Most of the resists used in the liquid crystal display are composed of novolak-based or acrylate-based resins, so that they are easily dissolved in an aqueous alkali solution. The resin is easily dissolved in an aqueous alkali solution because an alkali cation present in an ionic form in the EBR cleaning solution reacts with the acid group of the resin to form a salt that can be dissolved in water.

Preferred organic or inorganic alkalis for use in the cleaning solution of the present invention include one of inorganic alkalis such as potassium hydroxide, potassium carbonate and sodium carbonate, organic alkalis such as tetramethylammonium hydroxide and tetraethylammonium hydroxide. , Or mixtures of two or more. Suitable content of organic or inorganic alkali is 0.1 to 10% by weight, more preferably 1 to 5% by weight. If the organic or inorganic alkali content is more than 10% by weight, there is a risk that inorganic matters may remain or precipitate after the EBR process, which may be a source of contamination of the post-processing equipment, and the waste liquid is difficult to treat, which is not preferable.

In the washing solution of the present invention, the polar organic solvent is preferably a non-amine organic solvent having a polar value of 4.2 or more. The polar value of the organic solvent used in the present invention is a polar value (Journal of chromatographic science, 16: 223, 1978, polarity index, P ′) defined by RL snyder among various methods of defining polar values. Table 1 shows the polarity as an example.

menstruum Polarity menstruum Polarity Methyl sulfoxide 7.2 Ethyl acetate 4.4 Dimethylacetamide 6.5 Propanol 4.0 Dimethylformamide 6.4 Butyl diglycol 4.7 Triethylene glycol 5.6 Diethylene glycol 5.2 Methyl Isobutyl Ketone 4.2 Butyl acetate 3.9

A polar organic solvent with a polarity of 4.2 or more is excellent in dissolving ability to resin, which is the main component of resist, and can be dissolved in water, thereby increasing the cleaning power of the cleaning solution. Organic solvents such as hexane, xylene, isopropanol, butanol, tetrahydrofuran, butyl acetate, etc. having a polarity of less than 4.2 are not suitable because they are not effective in dissolving or being insoluble in water. In addition, amines are undesirable for use because they react with the resin, which is a component of the resist, after EBR treatment to produce polymers that are not removed in the resist developer, causing EBR defects.

Preferred solvents having a polar value of 4.2 or more for use in the present invention include amide organic solvents such as dimethylacetamide, diethylacetamide, dimethylformamide, diethylformamide and methylformamide; Sulfur oxide organic solvents such as methyl sulfoxide and methyl sulfonone; Glycol organic solvents such as triethylene glycol, tetraethylene glycol, butyl diglycol, butyl glycol and benzyl ethylene glycol benzyl diethylene glycol, and a mixture of two or more of them may be used. The content of the polar organic solvent in the cleaning solution according to the present invention is preferably 1 to 25% by weight. If the content of the polar organic solvent is 25% by weight or more, resist swelling or build-up occurs during EBR treatment, which is not preferable.

The amphoteric surfactant used in the cleaning solution of the present invention is preferably at least one mixture selected from lauryl betaine, lauryl sulfobetaine, stearyl betaine, lauryl dimethylamine oxide and the like. An important consideration when choosing a zwitterionic surfactant should be a substance that can have both zwitterions at high pH. Zwitterionic surfactants have both ions (negative and positive charges) compared to other surfactants, which can enhance the cleaning effect with excellent affinity and penetration into the resist. Resin, which is the main component of the resist, is negative because it has a negative charge in an aqueous alkali solution, which is undesirable because it is adsorbed on the resist, and anionic surfactants are not preferable because they have the same negative charge as resin. Nonionic surfactants do not have a charge and thus have no problem in use, but are not superior to zwitterionic surfactants in terms of affinity. In addition, the amphoteric ionic surfactant has an antistatic effect in the strong alkaline EBR cleaning solution, which is excellent in preventing the re-adsorption of foreign substances that cannot be expected from other surfactants (nonionic, anionic and cationic surfactants). The content of a zwitterionic surfactant suitable for EBR cleaning solution is 0.01 to 5% by weight, if more than 5% by weight is not suitable because a lot of foam occurs.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the following examples are for illustrating the present invention and the present invention is not limited by the following examples.

<Examples 1 to 8>

A black matrix (BM) forming resist and a blue, red, and green resist, which are commonly used for 5 inch LCD glass, are rotated and applied to a final film thickness of 1.5 μm, followed by vacuum drying for 1 minute. 1 torr or less) to prepare a specimen.

After the 5 inch glass specimens were erected vertically, about 0.5 cm of the edges of the specimens were immersed in the cleaning solution for 3 seconds, then taken out and immediately dried with N ₂ gun and washed with deionized water. The composition of the cleaning liquid is shown in Table 2 below.

Example alkali Polar Organic Solvents Zwitterionic Surfactant One KOH Na ₂ CO ₃ TMAH BEG BEDG BDG TEG DMF DMAc DMSO LB SB LSB 2 2% - 3% 4% 5% 2% One% 0.1% 3 One% 2% 5% 3% 3% 0.5% 4 One% 3% 4% 3% 5% 2% 5 2% 2% 5% 5% 2% 0.1 0.1% 6 2% 3% 5% 7% One% 7 3% One% 5% 5% 5% 0.1% 8 3% One% 4% 3% 3% 0.2% One%

The remaining weight percent in Table 2 is deionized water. The terms used in Table 2 have the following meanings.

Na ₂ CO ₃ : Sodium carbonate KOH: Potassium hydroxide TMAH: Tetramethylammonium hydroxide BEG: Benzyl ethylene glycol BDEG: Benzyl diethylene glycol BDG: Butyl diglycol TEG: Triethylene glycol DMF: Dimethylformamide DMAc: Dimethyl Acetamide DMSO: Methyl sulfoxide LB: Laurylbetaine SB: Stearylbetaine LSB: Laurylsulfobetaine.

<Comparative Examples 1 to 4>

It carried out similarly to Example 1 using the washing | cleaning liquid which has a composition of the following Table 3.

Comparative example alkali Polar Organic Solvents Nonionic, Anionic Surfactants Deionized water Comparative Example 1 - PGME 50%, n-BA 50% - - Comparative Example 2 TMAH 4% DPGME 10% EOPO 0.5% 85.5% Comparative Example 3 - MEA 10%, DPGME 10% OP-10 0.5% 79.5% Comparative Example 4 KOH 4% - NS 0.5% 95.5%

EOPO: ethylene propylene block polymer OP-10: octyl phenol ethoxylate NS: naphthalene sulfonate MEA: monoethanolamine DPGME: dipropylene glycol methyl ether PGME: propylene glycol methyl ether n-BA: butyl acetate

<EBR Experimental Evaluation>

It was shown in Table 4 by observing whether the profile was cleanly formed in a straight line by the cleaning liquid compositions of Examples 1-8 and Comparative Examples 1-4, and whether there was any reattachment foreign matter in the melted portion.

Composition profile Reattachment Example 1 Good radish Example 2 Good radish Example 3 Good radish Example 4 Good radish Example 5 Good radish Example 6 Good radish Example 7 Good radish Example 8 Good radish Comparative Example 1 Bad U Comparative Example 2 Good U Comparative Example 3 Bad U Comparative Example 4 Bad U

Pigment Dispersion Experiment

The 5 inch glass specimens prepared in the same manner as in Example 1 were divided into 4 portions, and 8 pieces were put in a 200 ml beaker containing 100 g of the composition of the Examples and Comparative Examples, and sufficiently dissolved. The specimen pieces were removed from the beaker and the composition was thoroughly stirred. When the composition was uniformly stirred, the agitation was stopped and the mixture was stirred to determine whether agglomerates were generated in the solution and the time until the agglomeration occurred. The results are shown in Table 5.

Composition Aggregate occurrence (within 2 hours) Time Example 1 radish - Example 2 radish - Example 3 radish - Example 4 radish - Example 5 radish - Example 6 radish - Example 7 radish - Example 8 radish - Comparative Example 1 U 5 sec Comparative Example 2 U 10 minutes Comparative Example 3 U 20 minutes Comparative Example 4 U 10 sec

As described above, the EBR cleaning solution according to the present invention can quickly and effectively remove unnecessary resist formed on the edge portion of the substrate in the liquid crystal display manufacturing process. In particular, the liquid crystal display manufactured by the EBR process as well as the subsequent process by not only quickly removing resists including pigments insoluble in alkaline aqueous solutions such as color resists and black resists, but also effectively removing the residues caused by insoluble pigments after washing. It can contribute to improving the reliability, performance and yield of the device.

Claims (7)

0.1 to 10 wt% of organic or inorganic alkali, 1 to 25 wt% of non-amine polar organic solvent, 0.01 to 5 wt% of zwitterionic surfactant, and 60 to 95 wt% of deionized water, based on the total weight of the composition. Cleaning solution for removing photoresist. The cleaning solution according to claim 1, wherein the organic or inorganic alkali is potassium hydroxide, potassium carbonate, sodium carbonate, tetramethylammonium hydroxide, tetraethylammonium hydroxide or a mixture thereof. The cleaning solution according to claim 1, wherein the non-amine polar organic solvent has a polarity of 4.2 or more and is an amide, a glycol, a sulfur oxide or a mixture thereof. The cleaning solution according to claim 1, wherein the zwitterionic surfactant is laurylbetaine, laurylsulfobetaine, stearylbetaine, lauryldimethylamine oxide or a mixture thereof. The cleaning solution according to claim 3, wherein the glycol organic solvent is triethylene glycol, tetraethylene glycol, butyl diglycol benzyl ethylene glycol, benzyl diethylene glycol or a mixture thereof. The cleaning solution according to claim 3, wherein the amide organic solvent is dimethylacetamide, diethylacetamide, dimethylformamide, diethylformamide, methylformamide or a mixture thereof. The cleaning solution according to claim 3, wherein the sulfur oxide organic solvent is methyl sulfoxide, methyl sulfonone or a mixture thereof.