JP2011186019A - Photosensitive conductive paste and method producing conductive pattern - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a photosensitive conductive paste for forming an organic-inorganic composite conductive pattern by which an organic-inorganic composite conductive pattern having low specific resistivity even in a low temperature curing condition can be obtained and which has the effect that fine patterning is possible by high photosensitive characteristics, and to obtain a method for producing the organic-inorganic composite conductive pattern. <P>SOLUTION: The photosensitive conductive paste includes a compound (A) having an alkoxy group, a photosensitive component (B) having an unsaturated double bond, an alicyclic compound (C) having a polymerizable group reacting with the photosensitive component (B) having the unsaturated double bond, a photopolymerization initiator (D) and a conductive filler (E). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

    The present invention relates to a photosensitive conductive paste for forming a conductive pattern.

    The conductive pattern in the present invention refers to a conductive pattern containing both an organic component containing a resin and an inorganic component containing a conductive filler and the like. In general, an inorganic conductive pattern can be obtained by applying and drying a paste containing a resin and a conductive filler, followed by baking. However, since it is necessary to bake at a high temperature of 500 ° C. or higher, it is provided on a substrate having low heat resistance. It has the disadvantage that it cannot. On the other hand, the organic-inorganic composite conductive pattern can be formed by processing at a relatively low temperature, but it has been relatively difficult to achieve high conductivity.

    Conventionally, in order to form the organic-inorganic composite conductive pattern as described above, a so-called conductive paste in which a large amount of fine particles of silver flakes, copper powder, or carbon particles are mixed in a resin or adhesive has been put into practical use. ing. Many of these are formed by a screen printing method and formed into a conductive pattern by heat curing (see, for example, Patent Documents 1 and 2).

    However, it has been difficult to achieve a high-definition pattern by the above screen printing method. In order to solve this problem, a conductive paste capable of acid etching (see, for example, Patent Document 3) and an ultraviolet curable conductive paste have been developed. For example, a paste in which conductive fine particles are dispersed in photosensitive polyimide is applied, dried, exposed, developed, and after forming a fine pattern, the conductive fine particles are brought into contact with each other by shrinking the resin by curing. A bump forming method for developing conductivity (for example, see Patent Document 4), a method for producing a conductive pad, wiring, and the like using a photosensitive conductive paste in which silver powder is dispersed in a photosensitive phenoxy resin. Known (for example, see Patent Documents 5 and 6).

    However, in the method described in Patent Document 3, it is necessary to form a resist layer on the coating film in order to perform patterning by the photolithography method, and there is a problem that the number of steps increases. In the method described in Patent Document 4, it is necessary to heat at about 400 ° C. in order to develop conductivity, and there is a problem that the base material to be used is limited. Further, in the methods described in Patent Documents 5 and 6, although a photosensitive phenoxy resin or a photosensitive acrylic-modified epoxy resin can be used to develop conductivity at a low temperature, the obtained conductive pattern has a high specific resistance value and 50 μm. There is a problem that the following fine patterning is difficult.

Japanese Patent Application No. 63-79727 Japanese Patent Application No. 2004-73740 Japanese Patent Application No. 8-237384 Japanese Patent Application No. 4-327423 Japanese Patent Application No. 58-17510 Japanese Patent Application No. 3-238020

    An object of the present invention is to solve the above-mentioned problems and to obtain a photosensitive conductive paste and a method for producing a conductive pattern that can exhibit conductivity at a relatively low temperature.

    The present invention relates to a compound (A) having an alkoxy group, a photosensitive component (B) having an unsaturated double bond, and an alicyclic ring having a polymerizable group that reacts with the photosensitive component (B) having an unsaturated double bond. A photosensitive conductive paste comprising a formula compound (C), a photopolymerization initiator (D), and a conductive filler (E).

    According to the present invention, a conductive pattern having a low specific resistivity can be obtained even under low-temperature curing conditions, and fine patterning is possible due to high photosensitivity, and fine bumps and wirings can be easily formed on various substrates. Can be formed.

    Further, by using a photopolymerization initiator or acid generator having a benzoyl skeleton, conductivity can be expressed even at lower temperature curing conditions.

It is the schematic diagram which showed the translucent pattern of the photomask used for the specific resistivity evaluation of an Example.

    The photosensitive conductive paste of the present invention has a polymerizable compound that reacts with the compound (A) having an alkoxy group, the photosensitive component (B) having an unsaturated double bond, and the photosensitive component (B) having the unsaturated double bond. A conductive filler (E) is dispersed in a photosensitive resin obtained by mixing an alicyclic compound (C) having a group and a photopolymerization initiator (D). The paste is a photosensitive conductive paste that can be applied on a substrate, dried to remove the solvent, and then a desired conductive pattern can be obtained on the substrate through exposure, development, and curing steps. The obtained conductive pattern is an organic-inorganic composite, and the conductive properties are exhibited when the conductive fillers come into contact with each other by curing shrinkage during curing.

    The compound (A) having an alkoxy group contained in the photosensitive conductive paste of the present invention is a compound having in its molecule an alkoxy group that generates an alcohol by heating to condense. Examples of the alkoxy group include a methoxy group, an ethoxy group, a butoxy group, an isobutoxy group, and the like. Preferably, the molecular weight of the alcohol generated during the condensation is relatively large. A butoxy group, an isobutoxy group, and the like are preferable, and at least one butoxy group is present. More preferably. Specific examples of such compound (A) include N-methoxymethyl acrylamide, N-ethoxymethyl acrylamide, Nn-butoxymethyl acrylamide, N-isobutoxymethyl acrylamide, butoxyethyl acrylate, butoxytriethylene glycol acrylate, Honshu HMOM-TPHAP (trade name) manufactured by Chemical Industry Co., Ltd., alkylated amino compound manufactured by Sanwa Chemical Co., Ltd., MW-30M, MW-30, MW-22, MS-11, MS-001, MX-730, MX- 750, MX-706, MX-035, BL-60, BX-37, MX-302, MX-45, MX-410, BX-4000, BX-37, Nicarak MW-30HM, Nicarak MW-390, Nicarak MX -270, Nikarak MX-280, Nikarak W-100LM, NIKALACK MX-750LM (trade name, "NIKALACK" is a registered trademark) and the like.

    The amount of the compound (A) having an alkoxy group contained in the photosensitive conductive paste of the present invention is preferably 10 to 300 parts by weight with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond. And more preferably 50 to 200 parts by weight. By making the addition amount with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond 50 parts by weight or more, it is possible to increase the shrinkage particularly during curing, and increase the contact probability between the conductive fillers. can do. As a result, the specific resistivity of the conductive pattern that is the final composition can be lowered. Further, by making the addition amount with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond 200 parts by weight or less, the tackiness of the paste composition film after removal of the solvent can be particularly reduced. It works preferentially in patterning, such as suppressing the occurrence of defects in the conductive pattern.

    The photosensitive component (B) having an unsaturated double bond contained in the photosensitive conductive paste of the present invention refers to a monomer, oligomer or polymer having at least one unsaturated double bond in the molecule. Or 2 or more types can be used. The photosensitive component (B) having an unsaturated double bond is not particularly limited, but it is desirable to include an alkali-soluble polymer for the development of the pattern processing of the present invention, because development with an alkaline aqueous solution rather than an organic solvent is preferable.

    Examples of the alkali-soluble polymer include acrylic copolymers. The acrylic copolymer is a copolymer containing at least an acrylic monomer as a copolymer component, and specific examples of the acrylic monomer include N-methoxymethylacrylamide, N-ethoxymethylacrylamide, Nn. -Butoxymethylacrylamide, N-isobutoxymethylacrylamide, methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, sec-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, allyl Acrylate, benzyl acrylate, butoxyethyl acrylate, butoxytriethylene glycol acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate Dicyclopentenyl acrylate, 2-ethylhexyl acrylate, glycerol acrylate, glycidyl acrylate, heptadecaflodecyl acrylate, 2-hydroxyethyl acrylate, isobornyl acrylate, 2-hydroxypropyl acrylate, isodexyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, trifluoroethyl acrylate, acrylamide, aminoethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, 1-naphthyl acrylate , 2-naphthyl acrylate, thiophenol acrylate, and those obtained by changing the methacrylate acrylic monomer and these acrylates such as benzyl mercaptan acrylate.

    As the copolymerization component other than the acrylic monomer, any compound having a carbon-carbon double bond can be used, but preferably styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, α- Examples thereof include styrenes such as methylstyrene, chloromethylstyrene, and hydroxymethylstyrene, γ-methacryloxypropyltrimethoxysilane, and 1-vinyl-2-pyrrolidone.

    In order to impart alkali solubility to the acrylic polymer, it can be achieved by using an unsaturated acid such as an unsaturated carboxylic acid as a monomer. Specific examples of the unsaturated acid include acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetate, and acid anhydrides thereof. By adding these to the molecular chain, the acid value of the polymer can be adjusted. The acid value of the polymer is preferably in the range of 80 to 140 from the viewpoint of developability.

    Specific examples of the monomer having two or more unsaturated double bonds in the molecule include allylated cyclohexyl diacrylate, 1,4-butanediol diacrylate, 1,3-butylene glycol diacrylate, ethylene glycol diacrylate, Diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, dipentaerythritol hexaacrylate, dipentaerythritol monohydroxypentaacrylate, ditrimethylolpropane tetraacrylate, glycerol diacrylate, methoxylated cyclohexyl diacrylate, neopentyl glycol diacrylate , Propylene glycol diacrylate, polypropylene glycol diacrylate, triglycero Diacrylate, trimethylolpropane triacrylate, bisphenol A diacrylate, diacrylate of bisphenol A-ethylene oxide adduct, diacrylate of bisphenol A-propylene oxide adduct, or 1 part or all of acrylic group of the above compound to methacrylic group Examples include substituted compounds.

    In addition, a part of the unsaturated acid in the acrylic polymer obtained by using the unsaturated acid such as the unsaturated carboxylic acid as a monomer as a monomer, a group that reacts with the unsaturated acid such as glycidyl (meth) acrylate, and the like. An alkali-soluble polymer having a reactive unsaturated double bond in the side chain obtained by reacting a compound having both groups having a saturated double bond can also be preferably used.

    The alicyclic compound (C) contained in the photosensitive conductive paste of the present invention has at least one structure in which carbon atoms are bonded in a ring, excluding an aromatic ring, and further has an unsaturated double compound. A compound having a polymerizable group capable of reacting with the photosensitive component (B) having a bond. Among structures in which carbon atoms are bonded in a cyclic manner, those excluding the aromatic ring include cyclopropane skeleton, cyclobutane skeleton, cyclopentane skeleton, cyclohexane skeleton, cyclobutene skeleton, cyclopentene skeleton, cyclohexene skeleton, cyclopropyne skeleton, cyclobutyne skeleton, cyclopentine skeleton , Cyclohexyne skeleton, hydrogenated bisphenol skeleton and the like. Examples of the polymerizable group capable of reacting with the photosensitive component (B) having an unsaturated double bond include an epoxy group, a glycidyl group, an acrylic group, a methacryl group, an isocyanate group, and an alkoxy group. Of these, photopolymerizable groups such as an epoxy group, an acrylic group, and a methacryl group are preferable. Specific examples of the alicyclic compound (C) included in the present invention include hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol A EO adduct diacrylate, and hydrogenated bisphenol A PO. Adduct diacrylate, EO adduct dimethacrylate of hydrogenated bisphenol A, PO adduct dimethacrylate of hydrogenated bisphenol A, EO adduct diacrylate of hydrogenated bisphenol F, PO adduct diacrylate of hydrogenated bisphenol F, water EO adduct dimethacrylate of hydrogenated bisphenol F, PO adduct dimethacrylate of hydrogenated bisphenol F, 2-acryloyloxyethyl hexahydrophthalic acid, dimethylol-tricyclodecane diacrylate, cyclohexyl acrylate, cyclohexyl meta Relate, tert-butylcyclohexyl acrylate, tert-butylcyclohexyl methacrylate, isobornyl acrylate, dicyclopentenyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethyl methacrylate, dicyclopentanyl methacrylate, etc. Among them, those having a cyclohexane skeleton having a three-dimensional spread are preferable because they have high reactivity and promote the condensation reaction by the alkoxy group of the compound (A) having an alkoxy group, and are hydrogenated having two cyclohexane skeletons. Those having a bisphenol skeleton are more preferred.

    The addition amount of the alicyclic compound (C) contained in the photosensitive conductive paste of the present invention is preferably in the range of 5 to 200 parts by weight with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond. More preferably, it is 30 to 60 parts by weight. By making the addition amount with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond 5 parts by weight or more, the condensation reaction by the alkoxy group of the compound (A) having an alkoxy group can be promoted. Further, by making the addition amount with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond 200 parts by weight or less, the tackiness of the paste composition film after removal of the solvent can be particularly reduced. It works preferentially in patterning, such as suppressing the occurrence of defects in the conductive pattern.

    The photopolymerization initiator (D) contained in the photosensitive conductive paste of the present invention refers to a compound that absorbs light of a short wavelength such as ultraviolet rays and decomposes to generate a radical. Specific examples include 1,2-octanedione, 1- [4- (phenylthio) -2- (O-benzoyloxime)], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2, 4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, ethanone, 1- [9-ethyl-6-2 (2-methylbenzoyl) -9H -Carbazol-3-yl] -1- (O-acetyloxime), benzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, 4 , 4'-dichlorobenzophenone, 4-benzoyl-4'-methyldiphenyl ketone, di Benzyl ketone, fluorenone, 2,2'-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-hydroxy-2-methylpropiophenone, pt-butyldichloroacetophenone, thioxanthone, 2-methylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, diethylthioxanthone, benzyl, benzyldimethyl ketal, benzyl-β-methoxyethyl acetal, benzoin, benzoin methyl ether, benzoin butyl ether, anthraquinone, 2-t-butylanthraquinone, 2-amylanthraquinone, β-chloroanthraquinone, anthrone, benzanthrone, dibenzosuberone, methyleneanthrone, 4-azidobenzalacetophenone, 2,6- (P-azidobenzylidene) cyclohexanone, 6-bis (p-azidobenzylidene) -4-methylcyclohexanone, 1-phenyl-1,2-butanedione-2- (o-methoxycarbonyl) oxime, 1-phenyl-propanedione 2- (o-ethoxycarbonyl) oxime, 1-phenyl-propanedione-2- (o-benzoyl) oxime, 1,3-diphenyl-propanetrione-2- (o-ethoxycarbonyl) oxime, 1-phenyl- 3-Ethoxy-propanetrione-2- (o-benzoyl) oxime, Michler's ketone, 2-methyl- [4- (methylthio) phenyl] -2-morpholino-1-propanone, naphthalenesulfonyl chloride, quinolinesulfonyl chloride, N-phenyl Thiacridone, 4, 4 -Photoreducing dyes such as azobisisobutyronitrile, diphenyl disulfide, benzthiazole disulfide, triphenylphosphine, camphorquinone, carbon tetrabromide, tribromophenyl sulfone, benzoin peroxide and eosin, methylene blue, ascorbic acid, tri A combination of reducing agents such as ethanolamine can be mentioned, but the invention is not particularly limited thereto. In the present invention, one or more of these can be used. Among them, those having a benzoyl skeleton in the molecule are preferred from the viewpoint of promoting the condensation reaction by the alkoxy group of the compound (A) having an alkoxy group, and 1,2-octanedione, 1- [4- ( Phenylthio) -2- (O-benzoyloxime)], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, ethanone, or 1 -[9-Ethyl-6-2 (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) is particularly preferred.

  The addition amount of the photopolymerization initiator (D) is preferably 0.05 to 30 parts by weight, more preferably 100 parts by weight of the photosensitive component (B) having an unsaturated double bond, and more preferably 5 to 20 parts by weight. By making the addition amount of the photopolymerization initiator (D) 5 parts by weight or more with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond, the cured density in the exposed area is particularly increased, and after development The remaining film rate can be increased. Moreover, the coating film by a photoinitiator (D) especially by making the addition amount of a photoinitiator (D) with respect to 100 weight part of photosensitive components (B) which have an unsaturated double bond into 20 parts weight or less. Excessive light absorption at the upper part can be suppressed, and the conductive pattern can be prevented from becoming an inversely tapered shape and the adhesiveness to the substrate being lowered.

    The photosensitive electrically conductive paste of this invention can add a sensitizer with a photoinitiator (D), a sensitivity can be improved, or the wavelength range effective for reaction can be expanded.

    As a photoinitiator (D) and a sensitizer, what has a sensitivity to a comparatively long wavelength is suitable. Since the shorter the wavelength of the light beam, the more easily affected by absorption and scattering, it is preferable to have sensitivity up to a relatively long wavelength in order to cure the inside of the coating film. Since many sensitizers have a sensitivity up to a relatively long wavelength, when used in combination with the photopolymerization initiator (D), the workability of a thick film is superior.

    Specific examples of the sensitizer include 2,4-diethylthioxanthone, isopropylthioxanthone, 2,3-bis (4-diethylaminobenzal) cyclopentanone, 2,6-bis (4-dimethylaminobenzal) cyclohexanone, 2,6-bis (4-dimethylaminobenzal) -4-methylcyclohexanone, Michler's ketone, 4,4-bis (diethylamino) benzophenone, 4,4-bis (dimethylamino) chalcone, 4,4-bis (diethylamino) Chalcone, p-dimethylaminocinnamylidene indanone, p-dimethylaminobenzylidene indanone, 2- (p-dimethylaminophenylvinylene) isonaphthothiazole, 1,3-bis (4-dimethylaminophenylvinylene) isonaphthothiazole 1,3-bis (4-dimethyl) Minobenzal) acetone, 1,3-carbonylbis (4-diethylaminobenzal) acetone, 3,3-carbonylbis (7-diethylaminocoumarin), N-phenyl-N-ethylethanolamine, N-phenylethanolamine, N- Examples include tolyldiethanolamine, isoamyl dimethylaminobenzoate, isoamyl diethylaminobenzoate, 3-phenyl-5-benzoylthiotetrazole, and 1-phenyl-5-ethoxycarbonylthiotetrazole. In the present invention, one or more of these can be used. When a sensitizer is added to the photosensitive conductive paste of the present invention, the addition amount is usually in the range of 0.05 to 10 parts by weight with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond. It is preferable that it is 0.1-10 weight part. The effect of improving the photosensitivity is easily exerted by setting the addition amount to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond to 0.1 parts by weight or more, and has an unsaturated double bond. By making the addition amount with respect to 100 parts by weight of the photosensitive component (B) 10 parts by weight or less, excessive light absorption occurs particularly at the upper part of the coating film, the conductive pattern becomes a reverse taper shape, and the adhesion to the substrate is improved. It can suppress that it falls.

    The conductive filler (E) contained in the photosensitive conductive paste of the present invention is at least one of Ag, Au, Cu, Pt, Pb, Sn, Ni, Al, W, Mo, ruthenium oxide, Cr, Ti, and indium. These conductive fillers can be used alone, as an alloy, or as a mixed powder. Moreover, the electroconductive particle which coat | covered the surface of the insulating particle or electroconductive particle with the above-mentioned component can be used similarly. Among these, Ag, Cu and Au are preferable from the viewpoint of conductivity, and Ag is more preferable from the viewpoint of cost and stability.

    The average particle diameter of the conductive filler (E) is preferably 0.5 to 10 μm, more preferably 1 to 6 μm. When the average particle size is 1 μm or more, the contact probability between the conductive fillers is improved, the specific resistance value of the conductive pattern to be produced, and the disconnection probability can be lowered, and the ultraviolet rays at the time of exposure smoothly in the film And fine patterning becomes easy. If the average particle size is 6 μm or less, the surface smoothness, pattern accuracy, and dimensional accuracy of the printed circuit pattern are improved. The average particle diameter can be determined by a Coulter counter method, a photon correlation method, a laser diffraction method, or the like.

    The amount of the conductive filler (E) added is preferably in the range of 70 to 95% by weight, more preferably 80 to 90% by weight, based on the total solid content in the paste. By setting it as 80 weight% or more, especially the contact probability of the conductive fillers in the curing shrinkage at the time of curing can be improved, and the specific resistance value and the disconnection probability of the produced conductive pattern can be lowered. In addition, by setting it to 90% by weight or less, particularly ultraviolet rays at the time of exposure can smoothly pass through the film, and fine patterning becomes easy. Moreover, solid content removes a solvent from paste.

    The acid generator (F) contained in the photosensitive conductive paste of the present invention refers to a substance that reacts with light or heat to generate an acid. Due to the catalytic effect of the acid generated, it has the effect of accelerating the condensation reaction of the alkoxy group in the compound (A) having an alkoxy group at a low temperature. As a result, it is possible to develop conductivity under a lower temperature curing condition and reduce the specific resistivity.

    Examples of the photoacid generator include quinonediazide, diazodisulfone, and triphenylsulfonium substances, and examples of the thermal acid generator include sulfonium salts. Since the photoacid generator generates an acid in the exposed portion by exposure, a difference in solubility between the exposed portion and the unexposed portion is reduced, and there is a possibility that the patterning property may be adversely affected. From the viewpoint of acid strength, a sulfonium salt is more preferable.

    The addition amount of the acid generator (F) is preferably within a range of 0.01 to 5 parts by weight, more preferably 0 with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond. 0.05 to 5 parts by weight. By adding 0.05 parts by weight or more with respect to 100 parts by weight of the photosensitive component (B) having an unsaturated double bond, the function as a catalyst for the condensation reaction of the alkoxy group of the compound having an alkoxy group is remarkable. become. Moreover, the efficiency as a catalyst becomes high by setting it as 5 weight% or less.

    The photosensitive conductive paste of the present invention may contain a solvent. Examples of the solvent include N, N-dimethylacetamide, N, N-dimethylformamide, N-methyl-2-pyrrolidone, dimethylimidazolidinone, dimethyl sulfoxide, γ-butyrolactone, ethyl lactate, 1-methoxy-2-propanol, 1 -Ethoxy-2-propanol, ethylene glycol mono-n-propyl ether, diacetone alcohol, tetrahydrofurfuryl alcohol, propylene glycol monomethyl ether acetate and the like. A solvent can be used individually by 1 type, or 2 or more types can be mixed and used for it. The solvent may be added later for the purpose of adjusting the viscosity after preparing the paste.

    The photosensitive conductive paste of the present invention is a non-photosensitive polymer, plasticizer, leveling agent, surfactant, silane coupling agent that does not have an unsaturated double bond in the molecule as long as the desired properties are not impaired. Additives such as antifoaming agents and pigments can also be blended. Specific examples of the non-photosensitive polymer include epoxy resin, novolac resin, phenol resin, polyimide precursor, and closed ring polyimide.

    Specific examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, polyethylene glycol, glycerin and the like. Specific examples of the leveling agent include a special vinyl polymer and a special acrylic polymer.

    As silane coupling agents, methyltrimethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, hexamethyldisilazane, 3-methacryloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane Etc.

    The photosensitive electrically conductive paste of this invention is produced using a disperser, a kneader, etc. Specific examples of these include, but are not limited to, a three-roller, a ball mill, and a planetary ball mill.

  Next, the manufacturing method of the conductive pattern using the photosensitive electrically conductive paste of this invention is demonstrated. In order to produce a conductive pattern, the photosensitive conductive paste of the present invention is applied onto a substrate, heated to volatilize the solvent and dried. Thereafter, exposure is performed through a pattern formation mask, and a desired pattern is formed on the substrate through a development process. And it cures and produces a conductive pattern.

    Examples of the substrate used in the present invention include a silicon wafer, a ceramic substrate, and an organic substrate. Examples of the ceramic substrate include a glass substrate, an alumina substrate, an aluminum nitride substrate, and a silicon carbide substrate. Examples of the organic substrate include an epoxy substrate, a polyetherimide resin substrate, a polyetherketone resin substrate, a polysulfone resin substrate, and a polyimide. Although a film, a polyester film, etc. are mentioned, it is not limited to these.

    Examples of the method for applying the photosensitive conductive paste of the present invention to a substrate include spin coating using a spinner, spray coating, roll coating, screen printing, blade coater, die coater, calendar coater, meniscus coater, bar coater and the like. . Further, the coating film thickness varies depending on the coating method, the solid content concentration of the composition, the viscosity, and the like, but it is usually applied such that the film thickness after drying is in the range of 0.1 to 50 μm.

    Next, the solvent is removed from the paste composition film coated on the substrate. Examples of the method for removing the solvent include heat drying using an oven, a hot plate, infrared rays, and vacuum drying. Heat drying is preferably performed in the range of 50 ° C. to 180 ° C. for 1 minute to several hours.

    On the paste composition film after removal of the solvent, pattern processing is performed by photolithography. As a light source used for exposure, it is preferable to use i-line (365 nm), h-line (405 nm), and g-line (436 nm) of a mercury lamp.

    After exposure, a desired pattern is obtained by removing an unexposed portion using a developer. Developer solutions for alkali development include tetramethylammonium hydroxide, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate An aqueous solution of a compound such as dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine or hexamethylenediamine is preferred. In some cases, these aqueous solutions may contain polar solvents such as N-methyl-2-pyrrolidone, N, N-dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, and γ-butyrolactone, and alcohols such as methanol, ethanol, and isopropanol. , Esters such as ethyl lactate and propylene glycol monomethyl ether acetate, and ketones such as cyclopentanone, cyclohexanone, isobutyl ketone, and methyl isobutyl ketone may be used alone or as a developer. Moreover, what added surfactant to these alkaline aqueous solution can also be used as a developing solution. Developers for organic development include N-methyl-2-pyrrolidone, N-acetyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, hexamethyl phosphortriamide, etc. Can be used alone or in combination with methanol, ethanol, isopropyl alcohol, xylene, water, methyl carbitol, ethyl carbitol and the like.

    The development can be performed by a method such as spraying the developer on the surface of the coating film while leaving or rotating the substrate, immersing the substrate in the developer, or applying ultrasonic waves while immersing.

    After development, a rinsing treatment with water may be performed. Here, alcohols such as ethanol and isopropyl alcohol, and esters such as ethyl lactate and propylene glycol monomethyl ether acetate may be added to water for rinsing treatment.

    Next, the paste composition film is cured in order to perform a condensation reaction of the alkoxy group in the compound (A) having an alkoxy group. Examples of the curing method include oven drying, inert oven, hot plate, heat drying using infrared rays, vacuum drying, and the like. The curing temperature is preferably in the range of 130 to 400 ° C, more preferably 150 to 400 ° C. By setting the curing temperature to 150 ° C. or higher, the reaction rate of the condensation reaction of the compound (A) having an alkoxy group can be improved, and as a result, the contact probability between the conductive fillers is increased, and the specific resistivity is increased. Get smaller. In addition, since the photosensitive conductive paste of the present invention can obtain high conductivity with a relatively low temperature cure of 400 ° C. or lower, it can be used on a substrate having low heat resistance or in combination with a material having low heat resistance. it can. Thus, a conductive pattern can be produced through a curing process.

    Examples of the present invention will be described below, but the present invention is not limited to these examples. The materials and evaluation methods used in each example and comparative example are as follows.

<Patternability evaluation method>
A photosensitive conductive paste is applied on a substrate so as to have a dry thickness of 12 μm, dried, and a group of straight lines arranged in a certain line and space (L / S) is defined as one unit, and the L / S values are different. A conductive pattern was obtained by exposing, developing, and curing through a photomask having a translucent pattern having different types of units. The L / S values of each unit were 500/500, 250/250, 100/100, 50/50, 40/40, 30/30, 25/25, 20/20, and 15/15 (respective line widths). (Represents (μm) / interval (μm)). The pattern is observed using an optical microscope, a pattern having a minimum L / S value with no residue between the patterns and no pattern peeling is confirmed, and the minimum L / S value can be developed. S.

<Evaluation method of specific resistivity>
It exposed through the photomask which has the translucent part A of the pattern shown in FIG. 1, developed and cured, and the conductive pattern for a specific resistivity measurement was obtained. The line width of the conductive pattern is 0.400 mm, and the line length is 80 mm. The ends of the obtained pattern were connected with a surface resistance meter, the surface resistance value was measured, and the specific resistivity was calculated by applying to the following calculation formula. The film thickness was measured using a stylus step meter “Surfcom 1400” (trade name, manufactured by Tokyo Seimitsu Co., Ltd.). The film thickness was measured at three positions at random, and the average value of the three points was taken as the film thickness. The length measurement was 1 mm, and the scanning speed was 0.3 mm / s. The line width was determined by observing three positions at random with an optical microscope and analyzing the image data to obtain the average value of the three points as the line width.

Specific resistivity = surface resistance value × film thickness × line width / line length The materials used in Examples and Comparative Examples are as follows.

Compound (A) having alkoxy group
Nn-Butoxymethylacrylamide BX-4000 (trade name, manufactured by Sanwa Chemical Co., Ltd.)
Photosensitive component (B) having an unsaturated double bond
Acrylic polymer AP-003: an addition reaction of 0.8 equivalent of glycidyl methacrylate to a carboxyl group of a copolymer consisting of methacrylic acid / methyl methacrylate / styrene = 40/30/30 (weight average molecular weight 29000, Acid value 110) (Toray Industries, Inc.)
Alicyclic compound (C) having a polymerizable group that reacts with the photosensitive component (B) having an unsaturated double bond
Hydrogenated bisphenol A diglycidyl ether Hydrogenated bisphenol A EO adduct diacrylate 2-acryloyloxyethyl hexahydrophthalic acid dimethylol-tricyclodecane diacrylate Photoinitiator (D)
IRGACURE 907 (trade name, manufactured by Ciba Japan Co., Ltd.)
IRGACURE OXE-01 (trade name, manufactured by Ciba Japan Co., Ltd.)
Conductive filler (E)
The materials listed in Table 1 and those having an average particle size were used. The average particle size was determined by the following method.

<Measurement of average particle diameter>
The average particle diameter of the conductive filler (E) was measured by a dynamic light scattering particle size distribution meter manufactured by HORIBA.

Acid generator (F)
Sun-Aid SI-110 (trade name, manufactured by Sanshin Chemical Industry Co., Ltd.)
Solvent: γ-butyrolactone (Mitsubishi Gas Chemical Co., Ltd.)
Example 1
20 g of alkali-soluble acrylic polymer AP-003 (manufactured by Toray Industries, Inc., A-1) in a 100 ml clean bottle, 12 g of Nn-butoxymethylacrylamide, 9 g of hydrogenated bisphenol A diglycidyl ether, photopolymerization initiator OXE 4 g of -01 (manufactured by Ciba Japan Co., Ltd.), 0.6 g of acid generator SI-110 (manufactured by Sanshin Chemical Industry Co., Ltd., E-1) and 10 g of γ-butyrolactone (manufactured by Mitsubishi Gas Chemical Company, Inc.) And “Awatori Nertaro” (trade name: ARE-310, manufactured by Sinky Co., Ltd.) to obtain 55.6 g of a photosensitive resin solution (solid content: 82.0% by weight). The obtained photosensitive resin solution (7.71 g) and 42.29 g of Ag particles having an average particle diameter of 2 μm were mixed and kneaded using a three-roller “EXAKT M-50” (trade name, manufactured by EXAKT). A photosensitive conductive paste was obtained.

The obtained paste was applied on a glass substrate by screen printing, and prebaked in a drying oven at 100 ° C. for 10 minutes. Then, full-line exposure was performed using an exposure apparatus “PEM-6M” (trade name, manufactured by Union Optics Co., Ltd.) with an exposure amount of 70 mJ / cm ² (wavelength 365 nm conversion), and 0.5% Na ₂ CO ₃ solution was used. Immersion development was performed for 1 minute, rinsed with ultra pure water, and then cured at 180 ° C. for 1 hour in a drying oven. The film thickness of the patterned conductive pattern was 10 μm. When the line and space (L / S) of the conductive pattern was confirmed with an optical microscope, it was confirmed that the pattern was satisfactorily processed without any inter-pattern residue and pattern peeling up to L / S of 15/15 μm. And when the specific resistivity of the organic-inorganic composite conductive pattern was measured, it was 4.5 × 10 ⁻⁵ Ωcm.

Examples 2-8
The photosensitive conductive paste shown in Table 1 was produced in the same manner as in Example 1, and the evaluation results are shown in Table 2.

Comparative Examples 1-3
The photosensitive conductive paste shown in Table 1 was produced in the same manner as in Example 1, and the evaluation results are shown in Table 2.

A Translucent part

Claims (10)

Compound (A) having an alkoxy group, photosensitive component (B) having an unsaturated double bond, alicyclic compound having a polymerizable group which reacts with the photosensitive component (B) having an unsaturated double bond ( A photosensitive conductive paste comprising C), a photopolymerization initiator (D), and a conductive filler (E). The polymerizable group of the alicyclic compound (C) having a polymerizable group that reacts with the photosensitive component (B) having an unsaturated double bond is a photopolymerizable group having an epoxy group or an unsaturated double bond. The photosensitive conductive paste according to claim 1. The photosensitive electrically conductive paste in any one of Claims 1-2 in which the alicyclic compound (C) which has a polymeric group which reacts with the photosensitive component (B) which has the said unsaturated double bond has a cyclohexane skeleton. The photosensitive electrically conductive paste in any one of Claim 3 with which the alicyclic compound (C) which has a polymeric group which reacts with the photosensitive component (B) which has the said unsaturated double bond has hydrogenated bisphenol skeleton. The added amount of the alicyclic compound (C) having a polymerizable group that reacts with the photosensitive component (B) having an unsaturated double bond is 100 parts by weight of the photosensitive component (B) having an unsaturated double bond. The photosensitive conductive paste according to claim 1, wherein the amount is 15 to 60 parts by weight. The photosensitive conductive paste according to claim 1, wherein the photopolymerization initiator (D) contains a benzoyl skeleton in the molecule. The photopolymerization initiator (D) is 1,2-octanedione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)], 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. Bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, or ethanone, 1- [9-ethyl-6-2 (2 The photosensitive conductive paste according to claim 1, which is -methylbenzoyl) -9H-carbazol-3-yl]-, 1- (O-acetyloxime). Furthermore, the photosensitive electrically conductive paste in any one of Claims 1-7 containing an acid generator (F). The photosensitive conductive paste according to claim 8, wherein the acid generator (F) is a sulfonium salt. A photosensitive conductive paste according to any one of claims 1 to 9, which is coated on a substrate, dried, exposed and developed, and then cured at a temperature of 150 ° C or higher and 400 ° C or lower. Production method.

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