KR20070099070A - Composition for positive type photoresist - Google Patents

Abstract

A positive photoresist composition is provided to enhance the metal plating resistance under the strong alkali condition and to prevent the loss of silver, thereby lowering the cost for manufacturing a metal electrode. A positive photoresist composition comprises 100 parts by weight of an alkali-soluble cresol novolac resin as an alkali-soluble resin; 30-80 parts by weight of a photosensitive compound; 10-30 parts by weight of a methoxymethylmelamine-based resin as a thermosetting resin; 3-15 parts by weight of a sensitivity enhancer; and 30-120 parts by weight of a solvent. Preferably the alkali-soluble cresol novolac resin has a weight average molecular weight of 2,000-30,000; and the photosensitive compound is a diazide-based compound.

Description

Composition for Positive Photoresist {Composition for positive type photoresist}

The present invention relates to a composition for positive type photoresist, and more particularly, a composition for photoresist that is excellent in alkali resistance and plating resistance and is suitable for the field of metal plating under strong alkali conditions such as a silver (Ag) electrode manufacturing process of PDP. It is about. More specifically, the present invention relates to a photoresist composition useful for the production of a metal electrode having excellent alkali resistance and plating resistance at the same time as photosensitive speed, development contrast, sensitivity, resolution, and the like.

Photoresist and photoresist films include Cathode Ray Tubes (CRTs), liquid crystal displays (LCDs) and organic electroluminescent displays (EL or ELD), integrated circuits (ICs), printed circuit boards (PCBs), and electronic displays. It is used for manufacturing highly integrated semiconductors such as Photolithography and photo-fabrication techniques are used in the fabrication of these devices. The photoresist film requires a resolution sufficient to form a pattern having very thin lines and a small space area of 7 μm or less.

Through chemical changes in the molecular structure of the photoresist resin or photoresist, physical properties of the photoresist may be changed, such as change in solubility, coloring, and curing of a specific solvent.

As an example of the prior art of forming a metal electrode, a conventional method of manufacturing an Ag electrode of a PDP is described. A resin composition (hereinafter referred to as "silver paste") in which silver (Ag) particles are dispersed on a glass substrate is screened. The silver (Ag) electrode was manufactured by the method of apply | coating whole surface by the printing method, and then pre-bake, exposing, developing, drying, and baking.

In the conventional method, since the silver paste is completely coated on the glass substrate and unnecessary parts (outside the electrode formation) are removed through development, the manufacturing cost increases because the loss of the silver paste and the metal for forming the electrode (Ag, etc.) is too high. There was a problem.

An object of the present invention is applied to a process for producing a metal electrode by a metal plating method performed under a strong alkali conditions having excellent plating resistance to the metal electrode plating process carried out under a strong alkali conditions to solve such conventional problems. This is possible, and thereby to provide a composition for a positive photoresist that can significantly reduce the amount of loss of the metal (Ag, etc.) for the production of the metal electrode to reduce the manufacturing cost.

The present invention is excellent in photosensitivity, development contrast, sensitivity and resolution, and also has excellent alkali resistance and plating resistance, so that the metal electrode such as silver (Ag) electrode for PDP can be applied to the process of producing metal electrode under strong alkali conditions. It is intended to provide a positive photoresist composition. In addition, the present invention is to provide a positive photoresist composition that can significantly reduce the manufacturing cost by reducing the amount of metal for forming an electrode, such as Ag (silver) when manufacturing the metal electrode.

In order to achieve the above object, the present invention provides a positive photoresist composition comprising an alkali-soluble resin, a photosensitive compound, a thermosetting resin, a sensitivity enhancer and a solvent.

The foregoing general description and the following detailed description are all exemplary and are described in detail with respect to the claimed invention.

The objects and other aspects of the present invention will become more apparent from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the detailed description and embodiments are intended to illustrate the preferred embodiment of the present invention, so those skilled in the art will understand that various changes and modifications are possible within the spirit and scope of the present invention.

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

The alkali-soluble resin is not particularly limited but includes a thermosetting novolak resin which is a condensation product of phenol and aldehyde, and most preferably cresol novolak resin.

Novolak resins are obtained by polycondensation of phenol alone or in combination with aldehydes and acidic catalysts.

Although it does not specifically limit as phenols, Phenol, o-cresol, m-cresol, p-cresol, 2, 3- xylenol, 2, 5- chisylenol, 3, 4- chisylenol, 3, 5- kisylenol, 2 Monohydric phenols such as, 3,5-trimethylphenol-kisylenol, 4-t-butyl phenol, 2-t-butyl phenol, 3-t-butyl phenol and 4-methyl-2-t-butyl phenol; And 2-naphthol, 1,3-dihydroxy naphthalene, 1,7-dihydroxy naphthalene, 1,5-dihydroxy naphthalene, resorcinol, pyrocatechol, hydroquinone, bisphenol A, phloroglucinol, Polyhydric phenols, such as a pyrogallol, etc. are mentioned, It can be used individually or in combination of 2 or more types. In particular, a combination of m-cresol and p-cresol is preferable.

Examples of the aldehyde include, but are not particularly limited to, formaldehyde, trioxane, paraformaldehyde, benzaldehyde, acetaldehyde, propylaldehyde, phenylacetaldehyde, α- or β-phenyl propylaldehyde, o-, m- or p-hydroxybenzaldehyde And glutaraldehyde, terephthalaldehyde and the like, and can be used alone or in combination of two or more thereof.

The cresol novolac resin used in the present invention preferably has a weight average molecular weight (based on GPC) of 2,000 to 30,000.

In addition, the cresol novolak resin used in the present invention will vary the physical properties such as the photosensitivity rate and the residual film ratio according to the content ratio of meta / para cresol, the content of meta / para cresol is 4: 6 to 6 by weight It is preferable to mix in a ratio of 4: 4.

When the content of the meta cresol in the cresol novolak resin exceeds the above range, the photoresist rate is increased while the residual film rate is drastically lowered. When the content of the para cresol exceeds the above range, the photosensitivity is slowed.

The cresol novolac resin may be used alone as a cresol novolac resin of the meta / para cresol content of 4: 6 to 6: 4 by weight as described above, more preferably mixed resins having different molecular weights Can be. In this case, the cresol novolac resin (i) contains a cresol novolac resin having a weight average molecular weight (GPC basis) of 8,000 to 30,000 and (ii) a cresol novolac resin having a weight average molecular weight (GPC basis) of 2,000 to 8,000. It is preferable to mix and use in the ratio of 3: 3 to 9: 1.

Here, the term 'weight average molecular weight' is defined in terms of polystyrene equivalents, as determined by gel permeation chromatography (GPC). In the present invention, if the weight average molecular weight of the novolak resin is less than 2,000, the photoresist resin film may have a large thickness reduction in the non-exposed part after development, whereas if it exceeds 30,000, the development speed is lowered and the sensitivity is lowered. The novolak resin of the present invention can achieve the most preferable effect when the resin obtained after removing the low molecular weight component from the reaction product has a weight average molecular weight (2,000 to 30,000) in the above-described range. In removing the low molecular weight component from the novolak resin, it is convenient to use techniques including fractional precipitation, fractional dissolution, tube chromatography, and the like. Thereby, the performance of a photoresist resin film can be improved, especially scumming, heat resistance, etc. can be improved.

The novolak resin as the alkali-soluble resin provides an image that can be dissolved in an aqueous alkali solution without increasing the volume, and can provide high resistance to plasma etching when used as a mask during etching.

The photosensitive compound constituting the present invention also acts as a dissolution inhibitor that reduces the solubility of alkali novolak resin in alkali as a diazide photosensitive compound. However, when the compound is irradiated with light, the compound is converted into an alkali-soluble material, which increases the alkali solubility of the novolak resin.

The diazide photosensitive compound can be synthesized by esterification of a polyhydroxy compound and a quinone diazide sulfonic acid compound. The esterification reaction for obtaining the photosensitive compound is carried out by dioxane, acetone, tetrahydrofuran, methylethylketone, N-methylpyrrolidine, chloroform, trichloroethane, trichloro and the polyhydroxy compound and the quinonediazide sulfonic acid compound. Dissolved in a solvent such as ethylene or dichloroethane, and condensed by dropwise addition of a basic catalyst such as sodium hydroxide, sodium carbonate, sodium bicarbonate, triethylamine, N-methylmorpholine, N-methylpiperazine or 4-dimethylaminopyridine The obtained product is washed, purified and dried. It is possible to selectively esterify only specific isomers and the esterification ratio (average esterification rate) is not particularly limited, but the diazide sulfonic acid compound for the OH group of the polyhydroxy compound is 20 to 100%, preferably 60 to 90 Range of%. Too low an esterification ratio results in deterioration of pattern shape or resolution, and too high an effect of deterioration of sensitivity.

As the quinone diazide sulfonic acid compound, for example, 1,2-benzoquinone diazide-4-sulfonic acid, 1,2-naphthoquinone diazide-4-sulfonic acid, 1,2-benzoquinone diazide-5-sulfonic acid and 1, O-quinone diazide sulfonic acid compounds, such as 2-naphthoquinone diazide-5-sulfonic acid, other quinone diazide sulfonic acid derivatives, etc. are mentioned. The diazide photosensitive compound is preferably 1,2-benzoquinone diazide-4-sulfonic acid chloride, 1,2-naphthoquinone diazide-4-sulfonic acid chloride and 1,2-naphthoquinone diazide-5- At least one of sulfonic acid chlorides.

The quinonediazide sulfonic acid compounds themselves have a function as a dissolution inhibitor which lowers the solubility of the novolak resin in alkali. However, it decomposes in order to produce alkali-soluble resins upon exposure, thereby having the property of promoting dissolution of the novolak resin in alkali.

As the polyhydroxy compound, trihydroxy benzophenones such as 2,3,4-trihydroxy benzophenone, 2,2 ', 3-trihydroxy benzophenone, and 2,3,4'-trihydroxy benzophenone ; Tetrahydroxybenzophenones such as 2,3,4,4-tetrahydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone and 2,3,4,5-tetrahydroxybenzophenone ; Pentahydroxybenzophenones such as 2,2 ', 3,4,4'-pentahydroxybenzophenone and 2,2', 3,4,5-pentahydroxybenzophenone; Hexahydroxybenzophenones such as 2,3,3 ', 4,4', 5'-hexahydroxybenzophenone and 2,2,3,3 ', 4,5'-hexahydroxybenzophenone; Gallic acid alkyl esters; And oxyflavanes.

The diazide photosensitive compound used in the present invention is preferably 2,3,4,4-tetrahydroxybenzophenone-1,2-naphthoquinone diazide-sulfonate, 2,3,4-trihydrate Hydroxybenzophenone-1,2-naphthoquinonediazide-5-sulfonate and (1- [1- (4-hydroxyphenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl ) Ethyl] benzene) -1,2-naphthoquinonediazide-5-sulfonate. In addition, a diazide photosensitive compound prepared by reacting a diazide compound such as polyhydroxy benzophenone, 1,2-naphthoquinone diazide, and 2-diazo-1-naphthol-5-sulfonic acid can also be used. .

For such diazide photosensitive compounds, see Light Sensitive Systems, Kosar, J .; See John Wiley & Sons, New York, 1965, chapter 7.

Such a photosensitive compound (photosensitive agent) used as one component of the resin composition for positive photoresist of the present invention is selected from substituted naphthoquinone diazide-based photosensitive agents which are generally applied as a positive photoresist resin composition. Such photosensitive compounds are described, for example, in US Pat. No. 2,797,213; 3,106,465; 3,148,983; 3,201,329; 3,785,825, 3,802,885 and the like.

The diazide photosensitive compound may be used alone or in combination of two or more of 30 to 80 parts by weight based on 100 parts by weight of the alkali-soluble resin. If it is less than 30 parts by weight, it is undeveloped in the developer and the residual ratio of the photoresist film is considerably low. If it exceeds 80 parts by weight, it is not economical and the solubility in the solvent is low.

The photosensitive speed of the positive photoresist resin film of the present invention can be controlled by using the diazide photosensitive compound. For example, a method of controlling the amount of the photosensitive compound and 2,3,4-trihydroxybenzophene There is a method of controlling the ester reactivity between a polyhydroxy compound such as rice paddy and a quinonediazide sulfonic acid compound such as 2-diazo-1-naphthol-5-sulfonic acid.

The diazide-based photosensitive compound decreases the solubility of the alkali-soluble resin in the aqueous alkali solution developer before exposure by about 100 times, but after exposure, the diazide-based photosensitive compound becomes soluble in the aqueous alkali solution and becomes soluble in the aqueous alkali solution, compared with the non-exposed positive photoresist composition. Solubility is increased by about 1000 to 1500 times. The formation of microcircuit patterns such as LCDs and organic ELs utilizes these properties of photoresists. More specifically, when UV rays are applied to a photoresist coated on a silicon wafer or a glass substrate through a circuit-like semiconductor mask and treated with a developer, only a desired circuit pattern remains on the silicon wafer or the glass substrate.

The thermosetting resin is a methoxymethylmelamine-based resin and the like is preferably 10 to 30 parts by weight based on 100 parts by weight of alkali-soluble resin. When it is 10 parts by weight or more, the alkali resistance and plating resistance of the present invention are excellent, and when it is 30 parts by weight or less, the developing process becomes easy.

In addition, the methoxymethylmelamine-based resin is more preferably hexamethoxymethylmelamine (Hexamethoxymelamine) resin.

Since the present invention includes a thermosetting resin as described above, a cross-linking reaction of the thermosetting resin occurs during a heat treatment process for manufacturing a metal electrode, thereby greatly improving alkali resistance and plating resistance.

Said sensitivity enhancer is used in order to improve the sensitivity of the resin composition for positive photoresists. The sensitivity enhancer is a polyhydroxy compound having 2 to 7 phenolic hydroxyl groups and having a weight average molecular weight of less than 1,000 compared to polystyrene. Preferred examples include 2,3,4-trihydroxybenzophenone, 2,3,4,4-tetrahydroxybenzophenone, 1- [1- (4-hydroxyphenyl) isopropyl] -4- [ It is preferable that it is 1 or more types chosen from 1, 1-bis (4-hydroxyphenyl) ethyl] benzene.

The polyhydroxy compound used as the sensitivity enhancer is preferably used 3 to 15 parts by weight based on 100 parts by weight of the alkali-soluble resin. When the sensitivity enhancer is less than 3 parts by weight, the photosensitivity effect is insignificant, so that resolution, sensitivity, and the like are insufficient. When the sensitivity enhancer is more than 15 parts by weight, the sensitivity is increased and the window process margin is narrowed in the process.

The solvent is ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, acetone, methyl ethyl ketone, ethyl alcohol, methyl alcohol, propyl alcohol, isopropyl alcohol, At least one member selected from the group consisting of benzene, toluene, cyclopentanone, cyclohexanone, ethylene glycol, xylene, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether.

The content of the solvent is preferably about 30 to 120 parts by weight based on 100 parts by weight of the alkali-soluble resin. Within this range, the coating property of the present invention is excellent.

In addition to the composition of the above-mentioned components, the positive type photoresist resin composition according to the present invention is a conventional known component used in conventional photoresist resin compositions such as leveling agents, fillers, pigments, dyes, surfactants and the like. It may contain other components or additives.

Using the present invention looks at the process for producing a silver (Ag) electrode of the PDP. First, the entire surface of the resin composition of the present invention on a metal plate, and then, after the pre-bake, exposure, development, and post-bake processes, the remaining portions except for the site where the metal electrode is to be formed. After the photoresist layer was formed, the silver (Ag) plating process was performed to form a silver (Ag) electrode on the portion where the photoresist layer was not formed, and then the photoresist layer was removed. (Ag) An electrode is formed.

Thereafter, the silver (Ag) electrode formed on the metal plate may be separated from the silver (Ag) electrode through a peeling and transfer process, and then formed on the glass substrate.

At this time, in the post-heat treatment step, heat treatment is performed at 125 to 150 ° C. for 3 to 20 minutes so that the crosslinking reaction of the thermosetting resin in the composition can occur, and the silver (Ag) plating step is a strong alkali condition having a pH of 11 to 12 so that the silver plating is dense. Under the following conditions.

Features and other advantages of the invention as described above will become more apparent from the description of the non-limiting examples described below. However, the following examples are only to be illustrated as specific embodiments of the present invention and should not be understood as limiting the scope of the present invention.

Example  One

Cresol novolac resins as alkali-soluble resins; 34 parts by weight of 1,2-naphthoquinone-2-diazide-5-sulfonic acid chloride as a photosensitive compound based on 100 parts by weight of the alkali-soluble resin; 15 parts by weight of hexamethoxymethylmelamine as the thermosetting resin; 3.6 parts by weight of 2,3,4-trihydroxybenzophenone as a sensitivity enhancer; And 165 parts by weight of methyl ethyl ketone and 55 parts by weight of diethylene glycol monoethyl ether acetate as solvents were prepared. The prepared solution was coated on a SUS metal plate with a thickness of 3 μm, and then subjected to pre-bake, exposure, development, and post-bake processes, except for areas where the metal electrode is to be formed. After the photoresist layer was formed on the remaining portion, a silver (Ag) plating process was performed to form a silver (Ag) electrode on the portion where the photoresist layer was not formed, and then the photoresist layer was removed. Only the silver (Ag) electrode was separated from the metal plate, and then transferred onto a glass substrate to prepare a silver (Ag) electrode for PDP. At this time, the post-bake process was performed at 130 ° C. for 3 minutes, and the silver (Ag) plating process was performed under strong alkali conditions of pH 12. The results of evaluating various physical properties of the prepared positive photoresist resin layer are shown in Table 2.

Example  2- Example  4 and Comparative Example  One

In the same manner as in Example 1, except that the content of hexamethoxymethylmelamine, a thermosetting resin, the temperature and time of post-bake, and the pH conditions of the silver (Ag) plating process were changed as shown in Table 1. A positive photoresist resin layer and a silver (Ag) electrode were prepared. The results of evaluating various physical properties of the prepared positive photoresist resin layer are shown in Table 2.

Manufacture conditions division Hexamethoxymethylmelamine content (parts by weight) After heat treatment condition PH when silver (Ag) plating Temperature (℃) Minutes Example 1 15 130 3 12 Example 2 10 125 5 11 Example 3 20 140 10 12 Example 4 30 150 17 11 Comparative Example 1 0 100 2 11

Property results division Availability of silver (Ag) electrodes Physical properties of photoresist resin film Sensitivity (mJ / cm 3) Resolution (μm) Example 1 possible 65.1 2.5 Example 2 possible 64.8 3.0 Example 3 possible 64.7 3.0 Example 4 possible 64.5 3.0 Comparative Example 1 impossible 64.9 3.0

In the case of Comparative Example 1, the positive photoresist portion was peeled off during the silver (Ag) plating process, so that silver (Ag) electrode production was virtually impossible.

Properties of Table 2 were evaluated by the following method.

[Sensitivity evaluation]

After exposing the photoresist resin layer coated with a thickness of 3 μm by the exposure amount as described above, the resultant was developed for 60 seconds with an aqueous 2.38 mass% TMAH solution at room temperature for 60 seconds, washed with water for 30 seconds, and then the exposure amount was measured through an optical microscope.

[Resolution evaluation]

The composition (solution) prepared as described above was coated with a thickness of 3 μm, irradiated with ultraviolet rays using a photomask, and then developed in a 2.38% TMAH alkali developer, leaving unexposed portions to form a circuit. It was observed with an electron microscope.

The present invention is excellent in photosensitivity, development contrast, sensitivity and resolution, and also has excellent alkali resistance and plating resistance, so that the metal electrode such as silver (Ag) electrode for PDP can be applied to a process for producing a metal electrode under strong alkali conditions. Do.

In addition, the present invention can significantly reduce the manufacturing cost by reducing the amount of metal for forming the electrode, such as silver (Ag) when manufacturing the metal electrode.

Claims (12)

A composition for positive type photoresist comprising an alkali-soluble resin, a photosensitive compound, a thermosetting resin, a sensitivity enhancer, and a solvent. The positive type photoresist composition of claim 1, wherein the thermosetting resin is a methoxymethylmelamine resin. The positive type photoresist composition according to claim 2, wherein the methoxymethylmelamine-based resin is hexamethoxymethylmelamine resin. According to claim 1, wherein the composition comprises 30 to 80 parts by weight of the photosensitive compound, 3 to 15 parts by weight of the sensitivity enhancer, 10 to 30 parts by weight of the thermosetting resin and 30 to 120 parts by weight of solvent based on 100 parts by weight of the alkali-soluble resin Positive type photoresist composition, characterized in that. The composition for positive type photoresist according to claim 1 or 4, wherein the alkali-soluble resin is an alkali-soluble cresol novolak resin. The composition for positive type photoresist according to claim 1 or 4, wherein the photosensitive compound is a diazide compound. The method of claim 6, wherein the diazide photosensitive compound is 2,3,4,4-tetrahydroxybenzophenone-1,2-naphthoquinone diazide-sulfonate, 2,3,4-trihydroxybenzo Phenone-1,2-naphthoquinonediazide-5-sulfonate and (1- [1- (4-hydroxyphenyl) -isopropyl] -4- [1,1-bis (4-hydroxyphenyl) Ethyl] benzene) -1,2-naphthoquinone diazide-5-sulfonate The composition for positive type photoresists characterized by the above-mentioned. The method of claim 1 or 4, wherein the solvent is ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, propylene glycol monoethyl ether acetate, acetone, methyl ethyl ketone, ethyl alcohol, At least one member selected from the group consisting of methyl alcohol, propyl alcohol, isopropyl alcohol, benzene, toluene, cyclopentanone, cyclohexanone, ethylene glycol, xylene, ethylene glycol monoethyl ether and diethylene glycol monoethyl ether. Positive type photoresist composition. The composition of claim 5, wherein the cresol novolac resin has a weight average molecular weight (GPC basis) of 2,000 to 30,000. The composition of claim 5, wherein the cresol novolak resin has a meta / para cresol content of 4: 6 to 6: 4 by weight. 6. The cresol novolac resin according to claim 5, wherein the cresol novolac resin comprises (i) a cresol novolac resin having a weight average molecular weight (GPC basis) of 8,000 to 30,000 and (ii) a cresol novolac having a weight average molecular weight (GPC basis) 2,000 to 8,000. A positive photoresist composition, wherein the resin is a resin mixed in a ratio of 7: 3 to 9: 1. The method of claim 1 or 4, wherein the sensitivity enhancer is 2,3,4-trihydroxybenzophenone, 2,3,4,4-tetrahydroxybenzophenone and 1- [1- (4-hydroxy And phenyl) isopropyl] -4- [1,1-bis (4-hydroxyphenyl) ethyl] benzene.