WO2005047978A1

WO2005047978A1 - Aqueous resist composition

Info

Publication number: WO2005047978A1
Application number: PCT/JP2004/017309
Authority: WO
Inventors: Satoru Ishigaki; Kazuya Kimura; Kunio Matsuki
Original assignee: Showa Denko K.K.
Priority date: 2003-11-17
Filing date: 2004-11-15
Publication date: 2005-05-26

Abstract

There is provided a novel resist composition used for production of printed boards. The aqueous resist composition of the present invention comprises (A) a resin soluble in water or an aqueous alkali solution, (B) a cellulose derivative, (C) water and (D) a hydroxyl group-containing organic solvent, wherein the content of the cellulose derivative (B) in the resist composition is within a range from 0.001 to 1.0% by weight, the content of water (C) is within a range from 25 to 65% by weight, and the content of the hydroxyl group-containing organic solvent (D) is within a range from 15 to 50% by weight. According to the present invention, it is made possible to form an aligned pattern having a smooth surface with high accuracy while maintaining excellent adhesion and good tack of a resist by using a specific amount of water and a specific solvent even if a very small amount of a cellulose derivative is used.

Description

DESCRIPTION

AQUEOUS RESIST COMPOSITION

Cross-References to Related Applications This application claims benefit under 35 U.S.C. section 119(e) to United States Provisional Application Serial No. 60/605532 filed August 31, 2004. Technical Field The present invention relates to a resist composition, particularly an aqueous solution or dispersion type resist composition, • used for production of printed boards, and to a method for producing a resist-coated substrate using the same. Background Art A print^' circuit ^' board has hitherto been produced by forming a .resist coating film on an insulating substrate having a conductive metal layer such as copper foil (which may contain metal other than copper and is also referred to as a "copper clad substrate", hereinafter), exposing the resist coating film via a photomask having a desired pattern, developing the exposed resist coating film with water or alkali water, etching the conductive metal layer of the portion where no resist is remained with an etching solution, and removing the resist to form a desired wiring pattern. Examples of the method of forming a resist layer on a copper clad substrate includes a dry film method and a liquid resist coating method. In the liquid resist coating method, a dip^' coating method is known, in addition to a method of applying a liquid resist on a copper clad substrate by roll coating or screen printing. According to this method, the copper clad substrate is dipped in a large amount of a resist composition solution (generally solution) and, after pulling up the substrate, the solvent is vaporized by drying to form a resist coating film on the copper clad substrate. An organic solvent having high volatility has been used in the liquid resist composition used for dip coating method. For fear of an adverse influence on the human body and environment, for example, there has recently proposed a resist composition containing water as a solvent disclosed in Japanese Unexamined Patent Publication (Kokai) No. 05-27437. However, since an aqueous resist composition contains water having a low evaporation rate as a ^' solvent, it requires a long time to dry the resist composition after coating. Therefore, so-called "sagging" occurs during drying of the resist solution to cause a problem such as ununiform thickness of the coating film. To prevent "sagging", it is known to add a thixotropic agent (thixotropy imparting agent) or a thickener to a resist composition and, for example, Japanese Unexamined Patent Publication (Kokai) No. 2003- 233183 has proposed a composition using an inorganic ' thickener. Although uniformity of the thickness of the coating film is maintained, smoothness and adhesive strength of the coating film' are not necessarily sufficient. Particularly, further improvement in smoothness of. the coating film is required so as to obtain a wiring pattern with high accuracy. It has hitherto been proposed- to use, as an organic thixotropic agent or thickener, a cellulose derivative such as hydroxyalkyl cellulose (see, for example, Japanese Unexamined Patent Publication (Kokai) No. 55- 045725 and Japanese Unexamined Patent Publication (Kokai) No. 11-174667) . However, it has been known that a cellulose derivative in an aqueous cellulose derivative solution causes reversible gelation at a given . temperature, and thus the cellulose derivative is precipitated from the solution at the above temperature or higher and viscosity of the aqueous solution drastically decreases. Therefore, when an aqueous resist containing a cellulose derivative is applied and then dried at the gelation temperature or higher, severe "sagging" occurs as a result of a decrease in viscosity during drying. Furthermore, since a decrease in viscosity during drying changes a dispersed state of the composition, smoothness of the coating film deteriorates. Depending on the kind of the cellulose derivative, the gelation temperature is generally by far lower than the boiling point of water and it has hitherto been difficult to solve the above problems. Japanese Unexamined Patent Publication (Kokai) No. 2000-292922 discloses a photosensitive composition comprising a hydrophobic polymer and a water soluble polymer in a weight ratio (hydrophobic polymer/water soluble polymer) of 0.05 to 4.0 and also describes that a hydroxyalkyl cellulose can be used as the water soluble polymer. In case of the composition containing a large amount of such a cellulose derivative, however, the surface coated with the aqueous composition is not sufficiently dried because of hydrophilicity of the cellulose and thus the coated surface exhibits severe tack. Also the addition of water deteriorates smoothness of the coated surface and a problem such as deterioration of resolution .of a pattern has not been solved. Summary of the Invention An object of the present invention is to provide a resist composition containing water as a solvent, capable of forming a wiring pattern having a smooth surface with high accuracy while maintaining excellent adhesion and good tack of a resist. The present inventors have intensively studied and found that the above object can be achieved by using a specific amount of water and a specific solvent even if a very small amount of a cellulose derivative is used in a resist composition, comprising a water soluble or alkali soluble resin and cellulose derivative, and thus the present invention has been completed. The present invention is directed to the following [1] to [9] . [1] An aqueous resist composition^' comprising (A) a resin soluble in water or an aqueous alkali solution, (B) a cellulose derivative, (C) water and (D) a hydroxyl group-containing organic solvent, wherein the content of the cellulose derivative (B) in the resist composition is within a range from 0.001 to 1.0% by weight, the content of water (C) is within a range from 25 to 65% by weight, and the content of the hydroxyl group-containing organic solvent (D) is within a range from 15 to 50% by weight. [2] An aqueous resist composition comprising (A) a resin soluble in water or an aqueous alkali solution, (B) a cellulose derivative, (C) water, (D) a hydroxyl group- containing organic solvent, (E) a polymerizable unsaturated compound and (F) a photopolymerization initiator, wherein the content of the cellulose derivative (B) in the resist composition is within a range from 0.001 to 1.0% by weight, the content of water (C) is within a range from 25 to 65% by weight, and the content of the hydroxyl group-containing organic solvent (D) is within a range from 15 to 50% by weight. [3] The aqueous resist composition according to [1] or [2], wherein a weight ratio of the resin soluble in water or an aqueous alkali solution (A) to the cellulose derivative (B) , (A) /(B), is within a range from 10 to 1000. [4] The aqueous resist composition according to any one of [1] to [3], wherein the resin soluble in water or ^• an aqueous alkali solution (A) is a copolymer containing ( eth) acrylic acid as one of constituent monomers. [5] The aqueous resist composition according to any one of [1] to [4], wherein the cellulose derivative (B) is hydroxyalkyl cellulose. [6] The aqueous resist composition according to any one of [1] to [5] , wherein the hydroxyl group-containing organic solvent (D) is at least one among a monoalkyl ether of a diol compound, a monoester of a diol compound and an aliphatic carboxylic acid, and an α- hydroxycarboxylate ester. [7] A method for producing a resist-coated substrate, which comprises dipping an insulating substrate containing a conductive metal in the aqueous resist composition according to any one of [1] to [6] . [8] A method for producing a print circuit board, which comprises using the aqueous resist composition according to any one of [1] to [6] . [9] A print circuit board produced by using the aqueous resist composition according to any one of [1] to

[6].

Detailed Description of the Invention The present invention will now be described in detail. (A) Resin soluble in water or aqueous alkali solution The resin soluble in water or an aqueous alkali solution (A) (hereinafter also referred to as a "water or alkali soluble resin") used in the resist composition of the present invention refers to a resin soluble in water or an aqueous alkali solution such as aqueous sodium carbonate solution. The water or alkali soluble resin of the present invention has such properties that it is soluble in a developer and is slightly soluble in an etching solution, and is preferably a component containing a resin having a carboxyl group or anhydride group thereof in the molecule. Examples of the resin having a carboxyl group or anhydride group thereof in the molecule include an acrylic resin which is a copolymer containing (meth) acrylic acid and a ( eth) acrylate ester as a monomer, a copolymer of (meth) acrylic acid and ethylene, and a copolymer of maleic anhydride and ethylene or styrene. In view .of adhesion and tack, an acrylic resin is particularly preferable. The (meth) acrylic acid means methacrylic acid and/or acrylic acid. The water or alkali soluble resin (A) is preferably a photopolymerizable resin which can cause photopolymerization under exposure to ultraviolet rays, X-rays or electron beams in the presence or absence of a photopolymerization initiator and includes, for example, those having a plurality of polymerizable groups such as ethylenically unsaturated bond in the molecule. As the photopolymerizable resin, known resins can be used alone or in combination and can be selected from the following group of (1) to (5) : (1) a reaction product of an unsaturated hydroxyl compound and a resin having at least one functional group selected from among carboxyl group, carboxylic anhydride group, isocyanate group and epoxy group; (2) a reaction product of an unsaturated epoxy compound and a resin having at least one functional group selected from among carboxyl group, carboxylic anhydride group, isocyanate group, a ino group and hydroxyl group; (3) a reaction product of an unsaturated carboxylic acid or an unsaturated carboxylic anhydride and a resin having at least one functional group selected from among hydroxyl group, amino group, isocyanate group and epoxy group; (4) a reaction .product of an unsaturated amino compound and a resin having at least one functional group selected from among carboxyl group, carboxylic anhydride group, formyl group, keto group, isocyanate group and epoxy group; and (5) a reaction product of an unsaturated isocyanate compound and a resin having at least one functional group selected from among carboxyl group, carboxylic anhydride group,- amino group, hydroxyl group and epoxy group. While a weight-average molecular weight and an ^■ acid value (mgKOH/g) of these photopolymerizable resins are not specifically limited, the weight-average molecular weight is preferably within a range from 500 to 100,000, more preferably from 1,000 to 50,000, and most preferably 2,000 to 20,000, and the acid value is preferably within a range from 20 to 350, more preferably from 50 to 250, and most preferably from 80 to 200. The weight-average molecular weight is measured by gel permeation chromatography, and the acid value is measured by the procedure defined in JIS K5601. Specific examples of the unsaturated hydroxyl compound include 2-hydroxyethyl (meth) acrylate, 2- hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylates such as and diethylene glycol monoacrylate, polyethylene glycol mono (meth) acrylate such as triethylene glycol mono (meth) acrylate, 1, 4-butanediol mono (meth) acrylate, polyethylene glycol mono (meth) allyl ethers such as ethylene glycol mono (meth) allyl ether and diethylene glyc.ol mono (meth) allyl ether, N- methylolacrylamide, allyl alcohol, methallyl alcohol, hydroxystyrene, hydroxymethylstyrene and allyl phenol. Specific examples of the unsaturated epoxy compound include glycidyl (meth) acrylate, allyl glycidyl ether and 3, 4-epoxycyclohexyl methyl (meth) acrylate. As the unsaturated carboxylic acid and anhydride thereof, there can be used (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, sorbic acid, tetrahydrophthalic acid, cinnamic acid, nadic acid, oleic acid, linoleic acid, linolenic acid, eleostearic acid, ricanic acid, ricinoleic acid, arachidonic acid, and anhydrides thereof. Examples of the unsaturated amino compound include allylamine, diallylamine, aminostyrene, aminomethylstyrene, acrylamide, and a reaction product of an unsaturated carboxylic acid or a derivative . thereof and polyamine such as ethylenediamine. As the unsaturated isocyanate compound, there can be used 2-isocyanate ethyl (meth) acrylate, allyl isocyanate, and a reaction product of an unsaturated hydroxyl compound and polyisocyanate such as tolylene diisocyanate or xylylene diisocyanate. The resin having at least one functional group used in (1) to (5) is at least one homopolymer or copolymer selected from among an unsaturated carboxylic acid, an unsaturated carboxylic anhydride, an unsaturated isocyanate compound, an unsaturated epoxy compound, an unsaturated carboxyl compound and an unsaturated amino compound. Examples of the resin having a carboxyl group as a functional group include poly (meth) acrylic acid, a (meth) acrylic acid-methyl (meth) acrylate copolymer, a (meth) acrylic acid-styrene copolymer, a styrene-maleic anhydride copolymer, an ethylene- (meth) acrylic acid copolymer, terminal carboxylated polybutadiene, a terminal carboxylated butadiene-acrylonitrile copolymer, and an (anhydrous) carboxylic acid adduct of a phenol resin. Examples of the resin having a hydroxyl group include polyhydroxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate-styrene copolymer, hydroxyethyl (meth) acrylate-methyl ethacrylate copolymer, novolak type phenol resin, polyvinyl alcohol, partially saponified ethylene-vinyl acetate copolymer, polyglycerin, polyvinylphenol, carboxylic acid adduct of epoxy resin, polyethylene glycol, polypropylene glycol, terminal hydroxylated (hydrogenated) polybutadiene, terminal hydroxylated (hydrogenated) pentroleum resin, and a reaction product of polyhydric alcohol and polyhydric isocyanate. Examples of the resin having an epoxy group include polyglycidyl (meth) acrylate, a glycidyl (meth) acrylate- styrene copolymer, a glycidyl (meth) acrylate-methyl methacrylate copolymer, a reaction product of a. novolak type phenol resin and epichlorohydrin, a reaction product of polyhydric phenol and epichlorohydrin, and a reaction product of polyhydric alcohol and epichlorohydrin. Examples of the resin having an amino group include polyacrylamide, polyallylamine, a saponified product of polyvinylformamide, a saponified product of polyvinylacetamide, polyaminostyrene, an aminostyrene- styrene copolymer, a reaction product of a carboxyl group-containing resin and polyhydric amine, an urea resin and a melamine resin. Examples of the resin having an isocyanate group include poly-2-isocyanate ethyl (meth) acrylate, a 2- isocyanate ethyl (meth) acrylate-methyl.(meth) acrylate copolymer, and a reaction product of a polyhydric isocyanate compound and a polyhydric hydroxyl compound. Specific examples of more preferable resin among resins (1) to^' (5) include: (1-1) a reaction product of an unsaturated hydroxyl compound and a resin having a carboxylic anhydride group, for example, a reaction product of hydroxyethyl acrylate and a styrene-maleic anhydride copolymer, and reaction products obtained by further reacting these reaction products with a base; (1-2) a reaction product of an unsaturated hydroxyl compound and a resin having an isocyanate group (2-1) a reaction product of an unsaturated epoxy compound and a resin having a carboxyl group, for example, a reaction product of glycidyl acrylate and a methacrylic acid-methyl methacrylate copolymer, a reaction product of 3, 4-epoxy-cyclohexyl methylacrylate and a methacrylic acid-methyl methacrylate copolymer, and reaction products obtained by further reacting these reaction products with a base; and (3-1) a reaction product of an unsaturated carboxylic acid or an unsaturated carboxylic anhydride of a resin having an epoxy group, for example, a reaction product of acrylic acid and polyglycidyl methacrylate, and a reaction product of acrylic acid and a glycidyl methacrylate-methyl methacrylate copolymer. Among these, a copolymer containing (meth) acrylic acid as a kind of constituent monomers is preferable and an acrylic resin comprising a copolymerized or modified product of (meth) acrylic acid and an ester thereof is more preferable. Specific examples thereof include a reaction product of glycidyl acrylate and a methacrylic acid-methyl methacrylate copolymer, a reaction product of 3, 4-epoxy-cyclohexyl methylacrylate and a methacrylic acid-methyl methacrylate copolymer, and reaction products obtained by further reacting these reaction products with a base. As the photopolymerizable resin, there can also be used, in addition to the resins (1) to (5) , the followings: (6) a homopolymer or copolymer of a conjugated diene compound, and a modified product thereof, such as polybutadiene ; (7) a polymerizable unsaturated resin obtained by adding an unsaturated dicarboxylic acid or an anhydride thereof to an unsaturated bond in a fatty acid chain of an ester product of an epoxy resin and an unsaturated fatty acid; (8) a polymerizable unsaturated resin comprising an unsaturated fatty acid-modified high acid value alkyd resin; and (9) a mixture of a polymerizable unsaturated resin comprising a maleinated oil and an ethylenically unsaturated compound having at least one polymerizable unsaturated bond in the molecule. The -content of the resin (A) in the aqueous resist composition of the present invention is usually within a range from 5 to 40% by weight, preferably from 7 to 30% by weight, and particularly preferably from 9 to 25% by weight. When the content is_. less than 5% by weight, the thickness of the coating film formed on an insulating substrate is too thin and thus there may arise such a problem that the strength of the coating film decreases. When the content is more than 40% by weight, the thickness of the coating film is too thick and thus there may arise such a problem that viscosity drastically increases and the drying time increases. (B) Cellulose derivative The cellulose derivative (B) in the present invention is that in which an alkyl group, a hydroxyalkyl group or a carboxyalkyl group is introduced into a hydroxyl group of cellulose. Known cellulose derivatives can be used without limitation and hydroxyalkyl ^' cellulose is preferable. Examples of the alkyl group include methyl group, ethyl group, propyl group and butyl group; examples of the hydroxyalkyl group include hydroxyethyl group, hydroxypropyl group and hydroxybutyl group; and examples of the carboxyalkyl group include carboxymethyl group. Specific examples of the cellulose derivative include alkyl ethers of celluloses such as methyl cellulose, ethyl cellulose and benzyl cellulose; hydroxyalkyl ethers of hydroxyethyl cellulose and hydroxypropyl cellulose; alkylhydroxyalkyl ethers of methylhydroxyethyl cellulose, ethylhydroxyethyl cellulose, methylethylhydroxyethyl cellulose, methylhydroxypropyl cellulose and ethylhydroxypropyl cellulose; carboxyalkyl celluloses such as carboxymethyl cellulose; and cellulose esters such as cellulose acetate.^' The amount of the alkyl group or hydroxyalkyl group to be introduced can be set within any range according to the purposes, but is usually within a range from 0.05 to 2.5 equivalents per glucose unit contained in the cellulose. Among these, methyl cellulose, ethylhydroxyethyl cellulose, methylhydroxypropyl cellulose, ethylhydroxypropyl cellulose and hydroxypropyl cellulose are preferable and hydroxypropyl cellulose is particularly preferable. Commercially available cellulose derivatives can be used and examples thereof include HEC DAICEL (manufactured by DAICEL CHEMICAL INDUSTRIES, LTD.), Belmocoll (manufactured by Akzo Nobel Co., Ltd.), HEC (manufactured by SUMITOMO SEIKA CHEMICALS CO., LTD.), KLUCEL (manufactured by Sansyo Co., Ltd.), Metolose (manufactured by Shin-Etsu Chemical Co., Ltd.), Nisso HPC (manufactured by Nippon Soda Co., Ltd.) and Tylose (manufactured by Clariant Japan Co., Ltd.). The content of the cellulose derivative (B) is within a range from 0.001 to 1.0% by weight based on the aqueous resist composition of the present invention. When the content is not within the above range, it is difficult to obtain the effect of the present invention. When the content is more than 1.0% by weight, not only smoothness of the surface of the coating film deteriorates, but also the resulting coating film exhibits severe tack. When the content is less than 0.001% by weight, the resulting coating film has an ununiform thickness and poor appearance such as cissing or unevenness arises and, furthermore, smoothness of the surface of the coating film deteriorates In the present invention, a weight ratio of the water soluble or alkali soluble resin (A) to the cellulose derivative (B) , (A) / (B) , is preferably within a range from 10 to 1000. When the weight ratio (A) / (B) is more than 350, the content of the component (A) is preferably 15% by weight or more. (C) Water The aqueous resist composition of the present invention contains water (C) as a solvent. The amount of an organic solvent having high volatility can be reduced by containing water (C) . Also it is made possible to increase a fire point of the resist composition and to enhance safety during storage and transportation. The content of water (C) in the aqueous resist composition of the present invention is required so as to control gelation of the cellulose derivative and to obtain good shape of the coating film, and is within a range from 25 to 65% by weight, preferably from 25 to 60% by weight, more preferably from 30 to 56% by weight, still more preferably from 35 to 52% by weight, and most preferably from 35 to 50% by weight, based on the aqueous resist composition. When the content of water is more than the above range, gelation of the cellulose derivative is likely to occur, and thus the coating film has poor smoothness and it becomes difficult to obtain a pattern with high accuracy. When the content of water is less than the above range, solubility of the cellulose derivative deteriorates, and thus the coating film has poor smoothness and it becomes difficult to obtain a pattern with high accuracy. (D) Hydroxyl group-containing organic solvent The hydroxyl group-containing organic solvent (D) of the present invention is a compound having at least one hydroxyl group in the molecule and known organic solvents can be used without limitation. Among these organic solvents, an alcohol compound, a diol compound, a monoalkyl ether of a diol compound, a monoester of a diol compound and an aliphatic carboxylic acid, and an α- hydroxycarboxylate ester are preferable. Also these hydroxyl group-containing organic solvents can be used alone or in combination. The content of the component (D) in the aqueous resist composition of the present invention is within a range from 15 to 50% 'by weight, preferably from 20 to 55% by weight, more preferably from 20 to 45% by weight, still more preferably from 25 to 45% by weight, and most preferably from 25 to 40%^' by weight, based on the aqueous resist composition of the present invention. When the content of the component (D) is less than 15% by weight, it is hard to suppress gelation of the cellulose derivative caused by heating, and thus the coating film has poor smoothness and it becomes hard to obtain a pattern with high accuracy. Furthermore, "sagging" occurs during drying and uniformity of the thickness of the coating film deteriorates. When the content is more than 50% by weight, solubility of the cellulose derivative deteriorates, and thus the coating film has poor smoothness and it becomes hard to obtain, a pattern with high accuracy. Specific examples of the hydroxyl group-containing organic solvent (D) include methanol, ethanol, 1- propanol, isopropanol, 1-butanol, 1-pentanol, ethylene glycol, propylene glycol, glycerin, 1, 2-propanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol monoacetate, diethylene glycol monoacetate, triethylene glycol monoacetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, propylene glycol monoacetate and dipropylene glycol monoacetate. There can also be used 1, 3-propanediol, 1,3- butanediol, 2-methyl-l, 3-propanediol, 2, 2-dimethyl-l, 3- propanediol, 2-methyl-l, 3-butanediol, 3-methyl-l, 3- butanediol, 1, 3-pentanediol, 2, 4-pentanediol, 1,3- hexanediol, 2, 4-hexanediol, trimethylolpropane, pentaerythritol, 3-methoxy-l-propanol, 2~methyl-3- methoxy-1-propanol, 2, 2-dimethyl-3-methoxy-l-propanol, 3- methoxy-1-butanol, 3-methoxy-3-methyl-l-butanol, those in which a ethoxy group of the above organic solvents is replaced by an ethoxy group or the other alkoxy group, 3- acetoxy-1-ρropanol, 2-methyl-3-acetoxy-l-propanol, 2,2- dimethyl-3-acetoxy-l-propanol, 3-acetoxy-l-butanol, 3- acetoxy-3-methyl-l-butanol, and those in which an acetoxy group- of the above organic solvents is replaced by the other acyloxy group. As the hydroxyl group-containing organic solvent (D) , an α-hydroxycarboxylate ester can also be used and known α-hydroxycarboxylate esters can be used without limitation. Specific examples of the α- hydroxycarboxylate ester include glycolate esters such as methyl glycolate, ethyl glycolate, . n-propyl glycolate, isopropyl glycolate, n-butyl glycolate, isobutyl glycolate, n-pentyl glycolate, n-hexyl glycolate and cyclohexyl glycolate; lactate esters such as methyl lactate, ethyl lactate, n-propyl lactate, isopropyl lactate, n-butyl lactate, isobutyl lactate, amyl lactate, isoamyl lactate, n-hexyl lactate, cyclohexyl lactate and benzyl lactate; α-hydroxybutyrate esters such as methyl α-hydroxybutyrate, ethyl α-hydroxybutyrate, n-propyl α- hydroxybutyrate, isopropyl α-hydroxybutyrate, n-butyl α- hydroxybutyrate, isobutyl α-hydroxybutyrate, n-pentyl α- hydroxybutyrate, n-hexyl α-hydroxybutyrate and cyclohexyl α-hydroxybutyrate; and α-hydroxyvalerate esters such as methyl α-hydroxyvalerate, ethyl α-hydroxyvalerate, n- propyl α-hydroxyvalerate, isopropyl α-hydroxyvalerate, n- butyl α-hydroxyvalerate, isobutyl α-hydroxyvalerate, amyl α-hydroxyvalerate, n-hexyl α-hydroxyvalerate and cyclohexyl α-hydroxyvalerate. To the resist composition of the present invention, other known organic solvents can also be added, if necessary. Examples of the solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone; aromatic hydrocarbons such as toluene, xylene, ethylbenzene and tetramethylbenzene; glycol ethers such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethylene glycol dimethyl ether, ethylene glycoldiethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether and diethylene glycol dibutyl ether; acetate esters such as methyl acetate, ethyl acetate and butyl acetate; aliphatic hydrocarbons such as methyl 3-methoxy-propionate, ethyl 3-methoxy- propionate, methyl 3-methoxy-butyrate, ethyl 3-methoxy- butyrate, methyl 3-methyl-3-methoxy-butyrate, ethyl 3- methyl-3-methoxy-butyrate, methyl 2-methoxy- cyclohexanecarboxylate, 3-methoxy-l-propyl acetate, 2- methyl-3-methoxy-l-propyl acetate, 2, 2-dimethyl-3- methoxy-1-propyl acetate, 3-methoxy-l-butyl acetate, 3- methoxy-3-methyl-l-butyl acetate, those in which a methoxy group of the above solvents is replaced by an ethoxy group or the other alkoxy group, those in which an acetoxy group of the above solvents is replaced by the other acyloxy group, octane, decane and cyclohexane; and pentroleum solvents such as pentroleum ether, pentroleum ^' naphtha, hydrogenated pentroleum naphtha and solvent naphtha. (E) Polymerizable unsaturated compound Preferably, the aqueous resist composition of the present invention further contains a polymerizable unsaturated compound (E) , in addition to the components (A) to (D) . The polymerizable unsaturated compound (E) is not specifically limited as far as it is a compound which is polymerized in the presence of a photopolymerization initiator (F) , and known polymerizable unsaturated compounds can be used alone or in combination. The content of the polymerizable unsaturated compound (E) in the resist composition of the present invention is within a range from 0.1 to 10% by weight, preferably from 0.5 to 7% by weight, and most preferably from 1 to 5% by weight, based on the aqueous resist composition of the present invention. When the content of the polymerizable unsaturated compound (E) is less than 0.01% by weight, photopolymerization does not sufficiently proceeds and it may become hard to maintain performances suited for use as the resist. When the content is more than 10% by weight, not only properties of the coating film deteriorate, but also the coating film exhibits severe tack. Examples of the polymerizable unsaturated compound include an unsaturated hydroxyl compound, an unsaturated epoxy compound, an unsaturated carboxylic acid or unsaturated carboxylic anhydride, an unsaturated amino compound, an unsaturated isocyanate compound, styrene, vinyltoluene, divinylbenzene, (meth) acrylic acid alkyl or aryl ester such as methyl methacrylate, a (meth) acrylate ester of a polyhydric alcohol, and an allyl ether of a polyhydric alcohol. Examples of the (meth) acrylate ester of the polyhydric alcohol include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, glycerin tri (meth) acrylate, pentaerythritol tetra (meth) acrylate and ethoxylated pentaerythritol tetra (meth) acrylate. Examples of the allyl ether of the polyhydric alcohol include ethylene glycol diallyl ether, diethylene glycol diallyl ether, diallyl ether, polyethyleneglycol diallyl ether, trimethylolpropane triallyl ether, glycerin triallyl ether and pentaerythritol tetraallyl ether. (F) Photopolymerization initiator As the photopolymerization initiator (F) , known photopolymerization initiators can be used. Specific examples thereof include benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl, diphenyl disulfide, tetramethylthiuram sulfide, diacetyl, eosin, thionine, Michler's ketone, anthraquinone, chloroanthraquinone,methylanthraquinone, α-hydroxyisobutylphenone, p- isopropyl-α-hydroxyisobutylphenone,- α,α' -dichloro-4- phenoxyacetophenone, 1-hydroxy-l-cyclohexylacetophenone, 2, 2-dimethoxy-2-phenylacetophenone,- methylbenzoyl formate, 2-methyl-l- [4- (methylthio) phenyl] -2- morpholinopropan-1-one, benzophenone, thioxanthone, 2- chlorothioxanthone, 2, 4-diethylthioxanthone, 2- isopropylthioxanthone, 4-benzoyl-4 ' -methyldiphenyl sulfide, ethyl N,N-dimethylaminobenzoate, pentyl' N,N- dimethylaminobenzoate and triethanolamine. These photopolymerization initiators may be used alone or in combination. The content of the photopolymerization initiator is within a range from 0.01 to 10% by weight, preferably from 0.1 to 5% by weight, and most preferably from 0.5 to 3% by weight, based on the aqueous resist composition of the present invention. When the content of the photopolymerization initiator (F) is less than 0.01% by weight, photopolymerization does not sufficiently proceed and it becomes difficult to maintain performances suited for use as the resist. When the content is more than 10% by weight, properties of the coating film may deteriorate. The photosensitive composition of the present invention can contain polymerization inhibitors so as to maintain stability during storage and processing. As the polymerization inhibitor, conventionally known polymerization inhibitors can be used. Examples thereof include phenols (for example, '3, 5-ditert-butyl-4- hydroxytoluene), hydroquinones (for example, hydroquinone and hydroquinone monomethyl ether) and catechols (for example, catechol, tert-butylcatechol and pyrogallol) . If necessary, there can be added known colorants such as acid blue, phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow, crystal violet, titanium oxide, carbon black and naphthalene black; silicone, fluorine and polymeric defoamers and/or leveling agents; and adhesion improvers such as imidazole, thiazole, triazole and silane coupling agents. To the resist composition of the present invention, surfactants can be added so as to adjust surface tension. The surfactant is not specifically limited and known surfactants can be used. Examples thereof include anionic surfactants (for example, sodium dodecylbenzenesulfonate, sodium laurate, and ammonium salt of polyoxyethylene alkyl ether sulfate) , nonionic surfactants (for example, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkylamine and polyoxyethylene alkylamide) and acetylene glycol surfactants. In the present invention, these surfactants can be used alone or in combination. A viscosity at 25°C of the resist composition of the present invention is preferably within a range from 5 to 500 mPa-S, more- preferably from 10 to 300 mPa-S, still- more preferably from 15 to 200 mPa-S, and most preferably from 20 to 150 mPa-S. When the viscosity is low, - thixotropy is hardly^' exhibited. When the viscosity is high, it becomes hard to adjust the thickness of the coating film upon dip coating. The viscosity can be measured by a commercially available B type rotation viscometer . The resist composition of the present invention can be prepared by mixing the above components according to . any method, for example, a method .of charging the respective components in a vessel equipped with a stirring blade while stirring. The respective components may be simultaneously or successively charged in a vessel for mixing. The respective components may be charged by a single or several portions. The temperature during mixing is not specifically limited and is usually within a range from 5 to 50°C, and is preferably from 10 to 40°C. The respective components may be mixed at a given temperature or mixed while varying the temperature. The resist composition of the present invention can be applied to any coating method, but is particularly useful for a dip coating method. The dip coating method is a known method and a coated substrate is produced by charging a large amount of a resist composition in a vessel, dipping an insulating substrate comprising a conductive metal layer such as copper clad laminate and vertically pulling up the insulating substrate at any rate. In that case, the resist composition in the vessel can be set to any temperature and the temperature is preferably within a range from 10 to 50°C. An apparatus used in the dip coating method is not specifically limited and known apparatuses can be used. To form a uniform film, an apparatus capable of varying a climbing rate during pulling up is preferably used. Examples of a commercially available dip coating apparatus include Full Automatic Dip Coater AD-7200, Semi Automatic Dip Coater SD-6200 and Five Coater SZC-720 (manufactured by SAZMA Communication Industry Co., Ltd.). A print circuit board having a desired wiring pattern is usually produced from the copper clad substrate obtained by the dip coating method through the steps of drying, exposure, development, etching and removal of the resist film and, if necessary, other optional steps. Examples As the respective components (A) to (F) of the resist, following were used. (A) Water or alkali soluble resin A 3,-4-epoxy-cyclohexylmethyl acrylate-modified resin of a methacrylic acid-methyl methacrylate copolymer (manufactured by DAICEL CHEMICAL INDUSTRIES, LTD. under the trade name of CYCLOMER ACA-200M, acid value: 100 mgKOH/g, weight-average molecular weight: 17,000) (B) Cellulose derivative (b-1) Hydroxyethyl cellulose (manufactured by Tokyo Kasei Kogyo Co. , Ltd. ) (b-2) Methyl cellulose (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

(b-3) Hydroxypropyl cellulose (manufactured by Nippon Soda Co. , Ltd. ) (b-4) Methylhydroxypropyl cellulose (manufactured by Shin-Etsu Chemical Co., Ltd.)

(b-5) Ethylhydroxyethyl cellulose (manufactured by Akzo Nobel Co. , Ltd. ) (D) Hydroxyl group-containing organic solvent

(d-1) Ethylene glycol monobutyl ether (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

(d-2) Propylene glycol monomethyl ether (manufactured by Tokyo Kasei Kogyo Co., Ltd.) (d-3) 3-methoxy-3-methyl-l-butanol (manufactured by Tokyo Kasei Kogyo Co., Ltd.)

(E) Polymerizable unsaturated compound

(e-1) Polyethylene glycol diacrylate (manufactured by KYOEISHA CHEMICAL Co., LTD) (e-2) Trimethylolpropane triacrylate (manufactured by KYOEISHA CHEMICAL Co., LTD)

(F) Photopolymerization initiator

(f-1) 2-methyl-l- (4-methylthiophenyl) -2-morpholinopropan-

1-one (manufactured by Ciba Speciality Chemical Co., Ltd.) (f-2) Diethylthioxanthone (manufactured by Ciba

Speciality Chemical Co., Ltd.) (Other components) .

Triethylamine (TEA) N-methyl morpholine (NMM)

(Organic solvents other than hydroxyl group-containing organic solvent)

Propylene glycol monomethyl ether acetate (PGMA)

(Thixotropic agent) Oxypropylene ammonium-modified smectite (SMC)

1) Preparation of resist composition The respective components shown in Table 1 other than the cellulose derivative (B) and water (C) were mixed in the ratio shown in Table 1 to obtain a uniform solution. Then, the amount described in Table 1 of water

(C) was added dropwise over 2 hours while vigorously stirring the mixture. Furthermore, the amount described in Table 1 of the cellulose derivative (B) was added, followed by stirring for 15 hours to prepare an aqueous resist composition. 5 2) Measurement of viscosity Using a B type viscometer (Model BL, No. 1 rotor) manufactured by TOKI SANGYO CO., LTD., the viscosity was measured at 25°C under the conditions of a rotor revolution of 6 rpm. 10 3) Dip coating with resist composition While maintaining the resist composition prepared in the item 1) at 35°C, the resist composition was dip-coated onto a double-sided copper clad laminate ^' (thickness of substrate: 130 μm, thickness of copper foil: 18 μm, 400 15 mm x 510 mm), using a dip coater (trade name: Five Coater FC-7500) manufactured by SAZMA Communication Industry Co., Ltd., and then the substrate was dried at 80°C for 15 minutes to obtain a coated substrate having a coating film made of the resist composition. The thickness of ^•20 the coating film was adjusted to about 8 μm by varying a pull-up rate during coating. - 4) Evaluation of tack Two dried coated substrates obtained in the item 3) were laid one upon another so that coated surfaces face 25 with each other and interposed between two stainless steels each measuring 400 mm x 510 mm x 1 mm, and then they are left to stand horizontally. After being left to stand in this state for 2 days (23°C, relative humidity: 60%), two substrates were gently peeled off. The 30 laminated coated surface -was divided into crosscuts each measuring 1 cm x 1 cm and the peeled state was evaluated by the number of crosscuts including the peeled portion according to the following criteria,. The results are shown in Table 1 below. 35 A: number of crosscuts including the peeled portion accounts for less than 2% of the entire crosscuts B: number of crosscuts including the peeled portion accounts for not less than 2% and less than 5% of_. the entire crosscuts

C: number of crosscuts including the peeled portion accounts for not less than 5% and less than 10% of the entire crosscuts

D: number of crosscuts including the peeled portion accounts for not less than 10% of the entire crosscuts

5) Measurement of adhesion Using a coating film adhesion tester manufactured by

ELCOMETER INC. (Adhesion Tester, Model F106, apparatus for measuring a peeling strength when peeling off an aluminum cylinder adhered onto the coated surface) , a peeling strength of the coating film was measured at room temperature.

6) Measurement of gloss Using a commercially available gloss meter (manufactured by TESTER SANGYO CO., LTD., OP-102), the measurement was conducted and the measured value was expressed by the value relative to -the gloss value 1 of Example 1. The results are shown in Table 1 below.

7) Measurement of line shape and resolution Evaluation after development The coated substrate obtained in the item 3) was exposed to ultraviolet rays (ultra-high mercury vapor lamp, main wavelength: 365 nm, 80 mJ/cm²) via a photomask having each five line-and-space (hereinafter sometimes abbreviated to L/S) patterns with 20 μm/20 to 80 μm/up to 80 μm line width and 10 μm pitch, developed by dipping in an aqueous 1% sodium carbonate . solution at 30°C for 60 seconds and then washed with water at 25°C. Linearity of line of the resist was evaluated by a scanning electron micrograph of the resulting substrate according to the following criteria. Among the patterns obtained without causing chipping of line and residue on development, resolution was expressed by the smallest value of L/S. The results are shown in Table 1 below.

A: line sidewall is nearly linear

B: meandering is observed in portion of line sidewall

C: meandering is observed in the entire line sidewall D: severe meandering is observed in line sidewall

Evaluation of etching After the development, the coated substrate was etched with an aqueous cupric chloride solution at 45°C for 60 seconds and then washed with water. The shape of remaining five resist lines of L/S = 40/40 was observed by a scanning electron micrograph of the resulting substrate and then evaluated according to the following criteria. The results are shown in Table 1 below.

A: number of patterns with chipping and warp is 0 to 1 among 5 patterns

B: number of patterns with chipping and warp is 2 to 3 among 5 patterns

C: number of patterns with chipping and warp is 4 among 5 patterns D: number of patterns with chipping and warp is 5 among 5 patterns

Evaluation after removal After the etching, the resist film was removed with an aqueous 3 wt% sodium hydroxide solution at 45°C, followed by washing and drying to obtain a substrate on which a copper wiring pattern is formed. The line shape of copper wiring of L/S = 40/40 was observed by a scanning electron micrograph of the resulting substrate and then evaluated according to the following criteria. The results are shown in Table.1 below.

A: number of patterns with remaining copper between copper wirings is^' 0 to 1 among 5 patterns

B: number of patterns with remaining copper between copper wirings is 2 to 3 among 5 pa-tterns C: number of patterns with remaining copper between copper wirings is 4 among 5 patterns

D: number of patterns with remaining copper between copper wirings is 5 among 5 patterns <Examples 2 to 6> In the same manner as in Example 1, except that components described in Table 1 were used as the respective components in the amount described in Table 1, aqueous resist compositions were prepared. In the same manner as in Example 1, evaluation was conducted. The results are shown in Table 1. <Comparative Example 1> In the same manner as in Example 1, except that hydroxyethyl cellulose was not used, an aqueous resist composition was prepared. In the same manner as in Example 1, evaluation was conducted. The results are shown in Table 1. <Comparative Example 2> In the same manner as in Example 1, except that the amount of hydroxyethyl cellulose was 2.0 parts by weight, an aqueous resist composition was prepared. In the same manner as in Example 1, evaluation was conducted. The results are shown in Table 1. <Examples 7 to 16> In the same manner as in Example 1, except that components described in Table 2 were used as the respective components in the amount described in Table 2, aqueous resist compositions were prepared. In the same manner as in Example 1, evaluation • was conducted. The results are shown in Table 2.

<Comparative Examples 3 to 7 and Examples 17 to 21> In the same manner as in Example 1, except that components described in Table 3 were used as the respective components in the amount described in Table 3, aqueous resist compositions were prepared. In the same manner as in Example 1, evaluation was conducted. The results are shown in Table 3. Table 1

Table 2

Table 3

Effect of the Invention The aqueous resist composition of the present invention is excellent in adhesion, tack and surface smoothness and can provide a print circuit board on which a wiring pattern with high accuracy is formed.

Claims

CLAIMS 1. An aqueous resist composition comprising (A) a resin soluble in water or an aqueous alkali solution, (B) a cellulose derivative, (C) water and (D) a hydroxyl group-containing organic solvent, wherein the content of the cellulose derivative (B) in the resist composition is within a range from 0.001 to 1.0% by weight, the content of water (C) is within a range from 25 to 65% by weight, and the content of the hydroxyl group-containing organic solvent (D) is within a range from 15 to 50% by weight. 2. An aqueous resist composition comprising (A) a resin soluble in water or an aqueous alkali solution, (B) a cellulose derivative, (C) water, (D) a hydroxyl group- containing organic solvent, (E) a polymerizable unsaturated compound and (F) a photopolymerization initiator, wherein the content of the cellulose derivative (B) in the resist composition is within a range from 0.001 to 1.0% by weight, the content of water

(C) is within a range from 25 to 65% by weight, and the content of the hydroxyl group-containing organic solvent

(D) is within a range from 15 to 50% by weight. 3. The aqueous resist composition according to claim 1 or 2, wherein a weight ratio of the resin soluble in water or an aqueous alkali solution (A) to the cellulose derivative (B) , (A) / (B) , is within a range from 10 to 100.0. 4. The aqueous resist composition according to claim 1 or 2, wherein the resin soluble in water or an aqueous alkali solution (A) is a copolymer containing (meth) acrylic acid as one of constituent monomers. 5. The aqueous resist composition according to claim 1 or 2, wherein the cellulose derivative (B) is hydroxyalkyl cellulose. 6. The aqueous resist composition according to claim 1 or 2, wherein the hydroxyl group-containing organic solvent (D) is at least one among a monoalkyl ether of a diol compound, a monoester of a diol compound and an aliphatic carboxylic acid, and an α- hydroxycarboxylate ester. 7. A method for producing a resist-coated substrate, which comprises dipping an insulating substrate containing a conductive metal in the aqueous resist composition according to claim 1 or 2. 8. A method for producing a print circuit board, which comprises using the aqueous resist composition according to claim 1 or 2. 9. A print circuit board produced by using the aqueous resist composition according to claim 1 or 2.