TW202043296A - Method for manufacturing electroconductive pattern - Google Patents

Abstract

The present invention provides a method for manufacturing an electroconductive pattern having an excellent electric conductivity in a low temperature of 100 DEG C or below. Provided is a method for manufacturing an electroconductive pattern having: (1) a step for forming a pattern including electroconductive particles (a) and a resin (b) on a substrate; and (2) a step for bringing an acidic aqueous solution into contact with the formed pattern, the acidic aqueous solution containing at least one type of salt in which the acid dissociation constant (pKa) of a conjugate acid of anions at 25 DEG C is 1.0 or below, and having a pH at 25 DEG C of 1.2 to 3.5.

Description

Manufacturing method of conductive pattern

The present invention relates to a manufacturing method of conductive patterns.

In recent years, touch panels as input means have been widely used. The touch panel is composed of a display part such as a liquid crystal panel, an organic EL (Electroluminescence) panel, and a touch sensor that detects input information at a specific location. The touch panel method is based on the detection method of the input position, and can be roughly classified into a resistive film method, an electrostatic capacitance method, an optical method, an electromagnetic induction method, an ultrasonic method, etc. Among them, capacitive touch panels are widely used for reasons such as high optical brightness, excellent design, simple structure, and excellent functions.

The touch sensor of the electrostatic capacitance type has a first electrode and a second electrode perpendicular to it via an insulating layer. A voltage is applied to the electrode on the touch panel surface to detect when touched by a conductive body such as a finger The contact position obtained by the change of the electrostatic capacitance is output as a signal. Regarding the wiring electrodes used in capacitive touch sensors, from the viewpoint that the wiring electrodes are not easily visible, transparent wiring electrodes such as indium tin oxide are generally used. However, in recent years, due to high sensitivity and screen With the increase in size, opaque wiring electrodes using metal materials have gradually become popular. In addition, in order to achieve high-definition, thin-film, and improved visibility of touch sensors, it is required to directly form opaque wiring electrodes in display parts of liquid crystal panels, organic EL panels, and the like. Therefore, in addition to patterning, it is also necessary to form conductive patterns at low temperatures. Therefore, a conductive paste containing a conductive filler, a zwitterionic compound, and a thermosetting compound (see, for example, Patent Document 1) has been proposed as a technique for forming a conductive pattern that can exhibit conductivity under low-temperature curing conditions. In addition, as a technique for reducing the resistance of the conductive pattern layer, a method has been proposed, which involves performing a strong acid treatment step of contacting the conductive pattern layer with a strong acid aqueous solution at room temperature and a weak acid contacting with a weak acid aqueous solution at a higher temperature than room temperature. In the processing step, at least a part of the metal particles in the conductive pattern layer is formed to be fused and connected to reduce the surface resistivity of the conductive pattern layer (see, for example, Patent Document 2). [Prior Technical Literature] [Patent Literature]

Patent Document 1'' International Publication No. 2014/208445 Patent Document 2 　 JP 2012-15143 Publication

[The problem to be solved by the invention]

Although the technology of Patent Documents 1 and 2 can exhibit conductivity at a lower temperature than before, in recent years, there is a demand for conductivity at a lower temperature, and conductivity at a low temperature below 100°C Insufficient topics.

In view of the foregoing problems, the present invention aims to provide a method for producing a conductive pattern with excellent conductivity even at a low temperature of 100°C or less. [Means to solve the problem]

The present invention is a method for manufacturing a conductive pattern, which has: (1) A step of forming a pattern on a substrate, the pattern including conductive particles (a) and resin (b); and (2) The step of contacting the formed pattern with an acidic aqueous solution with a pH of 1.2 to 3.5 at 25°C, the acidic aqueous solution containing at least one anion at 25°C, and the acid dissociation constant (pKa) of the conjugate acid is 1.0 or less Of salt. [Effects of the invention]

According to the present invention, even at a low temperature of 100°C or less, a conductive pattern with excellent conductivity can be formed.

[Pattern for implementing the invention]

The manufacturing method of the conductive pattern of the present invention has: (1) A step of forming a pattern on a substrate, the pattern including conductive particles (a) and resin (b) (there is a case described as step (1) below); and (2) The step of contacting the formed pattern with an acidic aqueous solution with a pH of 1.2 to 3.5 at 25°C. The acidic aqueous solution contains at least one anion at 25°C and the acid dissociation constant (pKa) of the conjugate acid is 1.0 or less的盐 (The case described as step (2) below). In the composite of the organic component of the conductive pattern-based resin (b) and the inorganic component of the conductive particles (a) obtained by the production method of the present invention, the conductive particles (a) are in contact with each other due to the atom diffusion phenomenon, thereby And show conductivity. The resin (b) is used as a bonding agent, which has the effect of improving the adhesion between the pattern and the substrate. By contacting the pattern with an acidic aqueous solution with a pH of 1.2 to 3.5 at 25°C, the diffusion of atoms from the surface of the conductive particles is promoted, and the conductivity can be improved even at a low temperature below 100°C. The acidic aqueous solution contains at least one The acid dissociation constant (pKa) of the conjugate acid of the anion at 25°C is 1.0 or less.

First, the step (1) will be described.

Examples of substrates include polyester films such as polyethylene terephthalate (hereinafter referred to as "PET") films, polyimide films, polyaramide films, epoxy resin films, and polyethers. Imide film, polyetherketone film, polyether-based film, glass substrate, silicon wafer, alumina substrate, aluminum nitride substrate, silicon carbide substrate, decorative layer forming substrate, insulating layer forming substrate, etc.

The pattern formed in step (1) contains conductive particles (a). Examples of the conductive particles (a) include particles of silver, gold, copper, platinum, lead, tin, nickel, aluminum, tungsten, molybdenum, chromium, titanium, indium, and these metal alloys. Two or more of the above may also be contained. Among them, from the viewpoint of conductivity, particles of metals selected from silver, gold, and copper are preferred, and silver particles are more preferred from the viewpoints of cost and stability.

The conductive particle (a) may have a layer structure of two or more layers. For example, it may also have a core-shell structure with a shell made of silver on the surface of a core made of copper. In addition, the surface of the conductive particle (a) may be coated with an organic component, an inorganic oxide, or the like. The organic component can function as a dispersant and conductive auxiliary agent for conductive particles of small particle size. Examples of organic components include fatty acids, amines, mercaptans, and cyanides.

The volume average particle diameter of the conductive particles (a) is preferably 0.1 μm or more from the viewpoint of appropriately suppressing the interaction between particles and improving the dispersibility of the conductive particles (a) in the pattern. On the other hand, from the viewpoint of improving the surface smoothness and dimensional accuracy of the conductive pattern and forming a fine conductive pattern, the volume average particle diameter of the conductive particles (a) is preferably 2.0 μm or less. Here, the volume average particle diameter of the conductive particles (a) is to use a solvent such as THF (tetrahydrofuran) that can dissolve the resin component to dissolve the formed pattern, perform centrifugal separation, and recover the solid component from which the resin component is removed. . Next, observe the conductive particles (a) with a scanning electron microscope (SEM) or a transmission electron microscope (TEM) from the recovered solid components, and randomly select 100 primary particles of the conductive particles (a) to obtain an image. For each primary particle, the circle-converted diameter is obtained by image analysis, and the volume-weighted average diameter is calculated, which can be obtained.

The content of the conductive particles (a) in the pattern is preferably 65 to 90% by mass. When the content of the conductive particles (a) is 65% by mass or more, the contact probability of the conductive particles (a) in the step (2) described later increases, and the conductivity can be further improved. On the other hand, when the content of the conductive particles (a) is 90% by weight or less, a fine pattern can be formed by the photolithography method. Here, the ratio of the conductive particles (a) in the conductive pattern can be calculated by scraping the formed pattern, and TG-DTA (differential thermal balance) is used to permeate the organic component at 400 to 600°C The ratio of the inorganic solid content in the conductive pattern is obtained by combustion, and the remaining inorganic solid content is dissolved in nitric acid, etc., and the conductivity of the inorganic solid content is measured by ICP-OES (Inductivity coupled plasma optical emission spectrometer; ICP-OES) The ratio of sexual particles (a).

The pattern formed in step (1) contains resin (b). Examples of resins include acrylic resins, polyester resins, phenol resins, epoxy resins, acrylic urethane resins, polyether urethane resins, phenoxy resins, polycarbonate resins, and polyamide resins. Amine resin, polyamide resin, polyamide resin, etc. Two or more of the above may also be contained.

When the pattern formation in step (1) is performed by a photoetching method, the resin (b) preferably has a carboxyl group, and it is preferable to use a photosensitive paste described later.

Examples of carboxyl group-containing resins include acrylic copolymers, carboxylic acid-modified epoxy resins, carboxylic acid-modified phenol resins, polyamide acids, and carboxylic acid-modified silicone polymers. Two or more of the above may also be contained. Among these, acrylic copolymers or carboxylic acid-modified epoxy resins with high ultraviolet light transmittance are preferred.

As the acrylic copolymer, a copolymer of an acrylic monomer and an unsaturated acid or an anhydride thereof is preferred, and a copolymer of other monomers having an unsaturated double bond may be further used.

Examples of acrylic monomers include methyl acrylate, ethyl acrylate (hereinafter referred to as "EA"), 2-ethylhexyl acrylate, and n-butyl acrylate (hereinafter referred to as "BA". ), isobutyl acrylate, isopropyl acrylate, glycidyl acrylate, butoxytriethylene glycol acrylate, dicyclopentyl acrylate, dicyclopentenyl acrylate, 2-hydroxyethyl acrylate, acrylic acid Isobornyl acrylate, 2-hydroxypropyl acrylate, isodecyl acrylate, isooctyl acrylate, lauryl acrylate, 2-methoxyethyl acrylate, methoxyglycol acrylate, methoxydiethyl Glycol acrylate, octafluoropentyl acrylate, phenoxyethyl acrylate, stearyl acrylate, trifluoroethyl acrylate, aminoethyl acrylate, phenyl acrylate, phenoxyethyl acrylate, acrylate-1- Naphthyl ester, 2-naphthyl acrylate, thiophenol acrylate, benzyl mercaptan acrylate, allylated cyclohexyl diacrylate, methoxylated cyclohexyl diacrylate, 1,4- Butylene glycol diacrylate, 1,3-butanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, new Pentylene glycol diacrylate, propylene glycol diacrylate, polypropylene glycol diacrylate, triglycerol diacrylate, trimethylolpropane triacrylate, di(trimethylolpropane) tetraacrylate, dineopentaerythritol Monohydroxy pentaacrylate, dineopentyl erythritol hexaacrylate, acrylamide, N-methoxy methacrylamide, N-ethoxy methacrylamide, N-n-butoxy methacrylate Amide, N-isobutoxy methacrylamide, methacrylphenol, methacrylamidephenol, γ-acryloxy propyl trimethoxysilane, N- (2-hydroxyphenyl)acrylamide, N-(3-hydroxyphenyl)acrylamide, N-(4-hydroxyphenyl)acrylamide, o-hydroxyphenyl acrylate, m-hydroxyphenyl acrylate, P-Hydroxyphenyl acrylate, 2-(2-hydroxyphenyl)ethyl acrylate, 2-(3-hydroxyphenyl)ethyl acrylate, 2-(4-hydroxyphenyl)ethyl acrylate, etc., These acryloyl groups are substituted with methacryloyl compounds. Among these, particularly preferred is a monomer selected from ethyl acrylate, 2-hydroxyethyl acrylate, and isobornyl acrylate. Two or more of the above can also be used.

Examples of unsaturated acids or anhydrides thereof include acrylic acid (hereinafter referred to as "AA"), methacrylic acid, itaconic acid, crotonic acid, maleic acid, fumaric acid, vinyl acetate, and the like. Acid anhydride and so on. Two or more of the above can also be used. The acid value of the acrylic copolymer can be adjusted according to the copolymerization ratio of the unsaturated acid.

Examples of other monomers having unsaturated double bonds include ortho-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene. Two or more of the above can also be used.

The carboxylic acid-modified epoxy resin is preferably a reaction product of an epoxy compound and an unsaturated acid or an unsaturated acid anhydride. Here, the so-called carboxylic acid-modified epoxy resin refers to the epoxy group of the epoxy compound modified with carboxylic acid or carboxylic anhydride, and does not contain an epoxy group.

Examples of epoxy compounds include glycidyl ethers, glycidyl amines, and epoxy resins. More specifically, as glycidyl ethers, for example: methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, ethylene glycol diglycidyl ether, two Ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, bisphenol A diglycidyl ether, hydrogenated bis Phenol A Diglycidyl Ether, Bisphenol F Diglycidyl Ether, Bisphenol S Diglycidyl Ether, Bisphenol Diglycidyl Ether, Bisphenol Diglycidyl Ether, Tetramethyl Bisphenol glycidyl ether, trimethylolpropane triglycidyl ether, 3,4-epoxycyclohexanecarboxylic acid-3',4'-epoxycyclohexyl methyl ester (3,4 -Epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate) etc. Examples of glycidylamines include tertiary butylglycidylamine. Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, biphenyl epoxy resin, novolak epoxy resin, hydrogenated bisphenol A epoxy resin, and the like. Two or more of the above can also be used.

Examples of the unsaturated acid or unsaturated acid anhydride include those previously exemplified as the raw material of the acrylic copolymer.

The unsaturated double bond can be introduced by reacting a compound having an unsaturated double bond such as glycidyl (meth)acrylate with the aforementioned acrylic copolymer and carboxylic acid-modified epoxy resin. Due to the introduction of unsaturated double bonds in the resin (b), the crosslinking density of the exposed part can be increased during exposure, the development margin can be enlarged, and a fine pattern can be formed.

As resin (b), it is preferable to use what has a phenolic hydroxyl group. The resin (b) has a phenolic hydroxyl group to form hydrogen bonds with polar groups such as hydroxyl groups and amine groups on the surface of the substrate, so that the adhesion between the pattern and the substrate can be improved.

The acid value of the resin (b) is preferably 50 to 250 mgKOH/g. If the acid value is 50 mgKOH/g or more, the solubility to the developer becomes high, and the generation of development residue can be suppressed. The acid value is more preferably 60 mgKOH/g or more. On the other hand, if the acid value is 250 mgKOH/g or less, excessive dissolution in the developer can be suppressed, and film damage of the pattern can be suppressed. The acid value is more preferably 200 mgKOH/g or less. In addition, the acid value of the resin (b) can be measured in accordance with JIS K 0070 (1992).

As a method of forming a pattern, for example, a paste containing the aforementioned conductive particles (a), resin (b), and other components as needed is used by screen printing, gravure printing, flexographic printing, and inkjet printing. A method of pattern formation by printing such as printing, or a method of pattern formation by a photoetching method having steps of exposure and development, etc. As a method of pattern formation by a photoetching method, for example, a method of coating a photosensitive photoresist on a non-photosensitive paste coating film, and forming a pattern through the steps of exposure, development, etching, and removal of the photoresist, and The photosensitive paste coating film is directly patterned by exposure and development steps. Among them, from the viewpoint of pattern thinning and reduction in the number of manufacturing steps, a method of patterning a photosensitive paste coating film by a photoetching method having steps of exposure and development is preferred.

The content of the conductive particles (a) in the paste is preferably 65 to 90% by weight in the solid content.

The method for forming a conductive pattern of the present invention preferably has a photoetching step. The photoetching step is to form a coating film by coating a photosensitive paste on a substrate, and to form a pattern by exposing and developing the coating film, wherein The photosensitive paste contains: conductive particles (a), carboxyl-containing resin (B) (also known as carboxyl-containing resin (B)), reactive monomer (c) with unsaturated double bond, and photopolymerization initiator (d). By forming such a conductive pattern, a fine pattern can be easily formed in a simple method.

Examples of the carboxyl group-containing resin (B) include the above-mentioned resin (b) having a carboxyl group. Two or more of the above may also be contained.

The acid value of the carboxyl group-containing resin (B), for example, in the case of an acrylic copolymer, can be adjusted to a desired range according to the ratio of unsaturated acids in the constituent components. In the case of a carboxylic acid-modified epoxy resin, it can be adjusted to a desired range by reacting a polybasic acid anhydride. In the case of carboxylic acid-modified phenol resin, the ratio of the polybasic acid anhydride in the constituent components can be adjusted to a desired range.

Examples of the reactive monomer (c) having an unsaturated double bond include acrylic monomers previously exemplified as raw materials for acrylic copolymers, styrene "below (St)", and the like. Two or more of the above may also be contained.

In addition, when the paste used in step (1) contains an acrylic copolymer and a reactive monomer (c) having an unsaturated double bond, the paste has an unsaturated double bond relative to 100 parts by weight of the acrylic copolymer The content of the reactive monomer (c) is preferably 1-100 parts by weight. By containing 1 part by weight or more of the reactive monomer (c) having an unsaturated double bond, a fine pattern can be formed. On the other hand, by containing 100 parts by weight or less of the reactive monomer (c) having an unsaturated double bond, curing shrinkage can be moderately suppressed, and conductivity can be further improved.

衍生物、苄基衍生物、安息香衍生物、肟系化合物、α-羥基酮系化合物、α-胺基烷基酚系化合物、膦氧化物系化合物、蔥酮化合物、蒽醌化合物等。作為二苯甲酮衍生物，可列舉例如：二苯甲酮、O-苯甲醯基安息香酸甲基、4,4'-雙(二甲基胺基)二苯甲酮、4,4'-雙(二乙胺基)二苯甲酮、4,4'-二氯二苯甲酮、茀酮、4-苯甲醯基-4'-甲基二苯甲酮等。作為苯乙酮衍生物，可列舉例如：對三級丁基二氯苯乙酮、4-疊氮基苯亞甲基苯乙酮、2,2'-二乙氧基苯乙酮等。作為9-氧硫𠮿

衍生物，可列舉例如：9-氧硫𠮿

、2-甲基9-氧硫𠮿

、2-氯9-氧硫𠮿

、2-異丙基9-氧硫𠮿

、二乙基-9-氧硫𠮿

等。作為苄基衍生物，可列舉例如：苄基、苄基二甲基縮酮、苄基-β-甲氧基乙縮醛等。作為安息香衍生物，可列舉例如：安息香、安息香甲基醚、安息香丁醚等。作為肟系化合物，可列舉例如：1,2-辛烷二酮-1-[4-(苯硫基)-2-(O-苯甲醯基肟)]、乙酮-1-[9-乙基-6-(2-甲基苯甲醯基)-9H-咔唑-3-基]-1-(O-乙醯基肟)、1-苯基-1,2-丁二酮-2-(O-甲氧羰基)肟、1-苯基-丙烷二酮-2-(O-乙氧羰基)肟、1-苯基-丙烷二酮-2-(O-苯甲醯基)肟、1,3-二苯基-丙烷三酮-2-(O-乙氧羰基)肟、1-苯基-3-乙氧基-丙烷三酮-2-(O-苯甲醯基)肟等。作為α-羥基酮系化合物，可列舉例如：2-羥基-2-甲基-1-苯基-丙烷-1-酮、1-[4-(2-羥基環氧基)-苯基]-2-羥基-2-甲基-1-丙烷-1-酮等。作為α-胺基烷基酚系化合物，可列舉例如：2-甲基-(4-甲基硫苯基)-2-

啉丙烷-1-酮、2-苄基-2-二甲基胺基-1-(4-

啉苯基)-丁烷-1-酮、2-二甲基胺基-2-(4-甲基苄基)-1-(4-

啉-4-基-苯基)丁烷-1-酮等。作為膦氧化物系化合物，可列舉例如：2,4,6-三甲基苯甲醯基-二苯基-氧化膦、雙(2,4,6-三甲基苯甲醯基)-苯基氧化膦等。作為蔥酮化合物，可列舉蔥酮、苯并蔥酮、二苯并環庚酮、亞甲基蔥酮等。作為蒽醌化合物，可列舉例如：蒽醌、2-三級丁基蒽醌、2-戊基蒽醌、β-氯蒽醌等。亦可含有2種以上之上述者。此等當中，較佳為光感度高的肟系化合物。The so-called photopolymerization initiator (d) refers to a compound that absorbs short-wavelength light such as ultraviolet light and causes decomposition or hydrogen abstraction reaction to generate free radicals. As the photopolymerization initiator (d), for example, benzophenone derivatives, acetophenone derivatives, and 9-oxysulfur 𠮿

Derivatives, benzyl derivatives, benzoin derivatives, oxime compounds, α-hydroxyketone compounds, α-aminoalkylphenol compounds, phosphine oxide compounds, onion compounds, anthraquinone compounds, etc. Examples of benzophenone derivatives include benzophenone, O-benzophenone benzoic acid methyl, 4,4'-bis(dimethylamino)benzophenone, 4,4' -Bis(diethylamino)benzophenone, 4,4'-dichlorobenzophenone, quinone, 4-benzyl-4'-methylbenzophenone, etc. Examples of acetophenone derivatives include p-tertiary butyldichloroacetophenone, 4-azidobenzylidene acetophenone, 2,2'-diethoxyacetophenone, and the like. As 9-oxysulfur 𠮿

Derivatives, for example: 9-oxysulfur 𠮿

, 2-Methyl 9-oxysulfur 𠮿

, 2-Chloro 9-oxysulfur 𠮿

, 2-isopropyl 9-oxysulfur 𠮿

, Diethyl-9-oxysulfur 𠮿

Wait. Examples of benzyl derivatives include benzyl, benzyl dimethyl ketal, benzyl-β-methoxy acetal, and the like. Examples of benzoin derivatives include benzoin, benzoin methyl ether, and benzoin butyl ether. Examples of oxime-based compounds include 1,2-octanedione-1-[4-(phenylthio)-2-(O-benzyloxime)] and ethyl ketone-1-[9- Ethyl-6-(2-methylbenzyl)-9H-carbazol-3-yl)-1-(O-acetoxime), 1-phenyl-1,2-butanedione- 2-(O-methoxycarbonyl)oxime, 1-phenyl-propanedione-2-(O-ethoxycarbonyl)oxime, 1-phenyl-propanedione-2-(O-benzyl) Oxime, 1,3-diphenyl-propanetrione-2-(O-ethoxycarbonyl)oxime, 1-phenyl-3-ethoxy-propanetrione-2-(O-benzyl) Oxime etc. Examples of α-hydroxy ketone compounds include 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-[4-(2-hydroxyepoxy)-phenyl]- 2-hydroxy-2-methyl-1-propan-1-one and so on. Examples of α-aminoalkylphenol-based compounds include 2-methyl-(4-methylthiophenyl)-2-

Phenylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-

Phenylphenyl)-butane-1-one, 2-dimethylamino-2-(4-methylbenzyl)-1-(4-

Lin-4-yl-phenyl)butan-1-one and the like. Examples of the phosphine oxide compound include 2,4,6-trimethylbenzyl-diphenyl-phosphine oxide, and bis(2,4,6-trimethylbenzyl)-benzene Based phosphine oxide and so on. Examples of onionone compounds include onionone, benzoonionone, dibenzocycloheptanone, and methylene onionone. Examples of the anthraquinone compound include anthraquinone, 2-tertiarybutylanthraquinone, 2-pentylanthraquinone, β-chloroanthraquinone, and the like. Two or more of the above may also be contained. Among these, oxime compounds with high photosensitivity are preferred.

The content of the photopolymerization initiator (d) in the photosensitive paste is preferably 1 to 30 parts by weight with respect to 100 parts by weight of the carboxyl group-containing resin (B). When the content of the photopolymerization initiator (d) is 1 part by weight or more, the curing density of the exposed portion increases, and the residual film rate after development can be increased. On the other hand, when the content of the photopolymerization initiator (d) is preferably 30 parts by weight or less, excessive light absorption due to the photopolymerization initiator (d) on the upper part of the pattern can be suppressed. As a result, a tapered pattern can be easily formed, and the adhesion to the substrate can be improved.

In addition to the above, the pattern forming paste can also be blended with additives such as solvents, plasticizers, leveling agents, surfactants, silane coupling agents, defoamers, and pigments.

Specific examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, polyethylene glycol, and glycerin. Specific examples of the leveling agent include special ethylene-based polymers, special acrylic-based polymers, and the like.

As the silane coupling agent, methyltrimethoxysilane, dimethyldiethoxysilane, phenyltriepoxysilane, hexamethyldisilazane, 3-methacryloxypropyltrimethyl Oxyoxysilane, 3-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, etc.

Examples of the solvent include: N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, 2-dimethylaminoethanol "below, (DMEA)'', dimethylimidazolidinone, dimethylsulfoxide, γ-butyrolactone, ethyl lactate, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, ethyl Glycol mono-n-propyl ether, diacetone alcohol, tetrahydrofurfuryl alcohol, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether acetate , Diethylene glycol monobutyl ether, diethylene glycol, 2,2,4,-trimethyl-1,3-pentanediol monoisobutyrate, etc. Two or more of the above may also be contained. The boiling point of the solvent is 150°C or higher. When the boiling point is above 150°C, the volatilization of the solvent is suppressed, and the thickening of the paste can be suppressed.

A method of patterning a photosensitive paste coating film by a photoetching method can be cited as an example, and step (1) will be further described in detail.

First, the conductive particles (a), resin (b), solvent, and other components as needed are mixed to make a paste. As a mixing device, for example, a three-roll mill, a ball mill, a star ball mill, etc., a disperser, a kneader, etc. can be mentioned.

Next, the obtained paste is applied on a substrate and dried. Examples of paste coating methods include spin coating using a spinner, spray coating, roll coating, screen printing, knife coater, die coater, calender coater, curved surface coater, or bar coater. Wait. As a drying method, for example, heating drying by an oven, a hot plate, infrared rays, etc., vacuum drying, etc. are mentioned. The drying temperature is preferably 50 to 180°C, and the drying time is preferably 1 minute to several hours.

Next, on the obtained coating film, exposure is performed through any mask for pattern formation to form a latent image. As a light source for exposure, the i-line (365nm), h-line (405nm) or g-line (436nm) of a mercury lamp is preferably used.

After exposure, develop by using a developer solution to dissolve and remove the unexposed part to form the desired pattern. As the developer in the case of alkali development, for example, tetramethylammonium hydroxide, diethanolamine, diethylaminoethanol, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, triethylamine, diethanolamine Ethylamine, methylamine, dimethylamine, dimethylaminoethyl acetate, dimethylaminoethanol, dimethylaminoethyl methacrylate, cyclohexylamine, ethylenediamine, hexamethylene two Aqueous solutions such as amines. Two or more of the above can also be used. Also, depending on the situation, one or more of N-methyl-2-pyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide can also be added to these aqueous solutions. , Dimethyl sulfide, γ-butyrolactone, etc.; alcohols such as methanol, ethanol, isopropanol, etc.; esters such as ethyl lactate, propylene glycol monomethyl ether acetate, etc.; cyclopentanone, cyclohexane Ketones such as ketones, isobutyl ketone and methyl isobutyl ketone; surfactants, etc.

As the development method, for example, a method of spraying the developer solution on the surface of the coating film while the substrate with the exposed paste coating film is left standing or rotating, and immersing the substrate with the exposed paste coating film in The method in the developer solution, the method of applying ultrasonic waves while immersing the substrate with the exposed paste coating film in the developer solution.

After developing, the cleaning solution can also be used for cleaning. As the cleaning liquid, for example, water, or an aqueous solution obtained by adding alcohols such as ethanol and isopropanol or esters such as ethyl lactate and propylene glycol monomethyl ether acetate to water.

The thickness of the pattern obtained in step (1) is preferably 3 μm or less. A fine conductive pattern can be formed by setting the thickness to 3 μm or less. In addition, the acidic aqueous solution becomes easy to penetrate, and even better conductivity can be obtained in a short time.

Next, step (2) will be described.

Step (2) is a step in which the pattern formed in step (1) is brought into contact with an acidic aqueous solution with a pH of 1.2 to 3.5 at 25°C, the acidic aqueous solution containing at least one conjugate acid of an anion at 25°C A salt having a dissociation constant (pKa) of 1.0 or less.

The acidic aqueous solution contains at least one salt of the conjugate acid of an anion at 25°C with an acid dissociation constant (pKa) of 1.0 or less. Here, the so-called "salt" refers to a component composed of cations and anions other than protons. In the present invention, "salts" also include those ionized into cations and anions in an aqueous solution. In addition, the cation also has some ions bonded to the hydroxyl group. In this case, the aqueous solution is acidic. The presence of the anion contained in the salt in the acid aqueous solution promotes the diffusion of atoms from the surface of the conductive particle (a), thereby improving conductivity. As described later, even if the pH is 1.2 or more, the presence of cations other than the protons contained in the salt in the acid aqueous solution can increase the anion concentration. As a result, it is possible to suppress the decrease in conductivity due to corrosion of the conductive particles (a) contained in the conductive pattern. By setting the pKa of the conjugate acid of the anion contained in the salt to 1.0 or less at 25° C., the diffusion of atoms of the conductive particles can be promoted and the conductivity can be improved. The pKa of the conjugate acid of the anion contained in the salt at 25°C is more preferably -5.0 or less. The pKa of the conjugate acid of the anion contained in the salt at 25°C can be identified after the anion contained in the salt is identified, and then the conjugate acid of the salt can be determined by the absorption analysis method. In addition, when the pKa of the conjugate acid of the anion contained in the salt is -2 or less, you can refer to literature values and the like.

The salt having the pKa of the conjugate acid of the anion at 25°C of 1.0 or less is not particularly limited as long as it is water-soluble, and examples include sodium nitrate, potassium nitrate, sodium chloride, potassium chloride, nickel (II) chloride, Iron chloride (II), iron chloride (III), tin chloride (II), copper chloride (II), sodium bromide, potassium bromide, nickel bromide (II), iron bromide (II), Iron(III) bromide, copper(II) bromide, sodium iodide, potassium iodide, nickel(II) iodide, sodium bisulfate, potassium bisulfate, sodium benzenesulfonate, potassium benzenesulfonate, sodium trifluoroacetate, Potassium trifluoroacetate and so on. Two or more of the above may also be contained.

The salt concentration is preferably 0.05 mol/L or more. By setting the salt concentration to 0.05 mol/L or more, the diffusion of atoms from the surface of the conductive particle (a) can be promoted, and the conductivity can be improved. Here, the "concentration of salt" refers to the total concentration of salt when two or more kinds of salt are contained.

The type and concentration of the salt whose pKa of the conjugate acid of the anion at 25°C contained in the acidic aqueous solution is 1.0 or less can be analyzed by ion chromatography, inductively coupled plasma mass spectrometry, etc.

The pH of the acidic aqueous solution at 25°C is 1.2 to 3.5. By setting the pH to 1.2 or more, the decrease in conductivity due to corrosion of the conductive particles (a) contained in the conductive pattern can be suppressed. On the other hand, by setting the pH to 3.5 or less, the diffusion of atoms from the surface of the conductive particle (a) can be promoted, and the conductivity can be improved. The pH is more preferably 2.5 or less. The pH can be measured by the glass electrode method from the potential difference between the two electrodes of the glass electrode and the comparison electrode.

In the acidic aqueous solution, as a component other than the above-mentioned salt, an acid may be contained in a predetermined pH range. The acid preferably contains an acid having an acid dissociation constant (pKa) of 2 to 5 at 25°C, that is, a weak acid. In the case of containing a polybasic acid, the pKa of the first stage that is most easily ionized is preferably 2-5; in the case of containing two or more acids, the pKa of the acid that is most easily ionized is preferably 2-5. By using a weak acid with a pKa of 2 or more, the long-term reliability affected by the acid remaining in the conductive pattern can be improved. On the other hand, by setting the pKa to 5 or less, the conductivity can be further improved. The pKa is more preferably 3.5 or less.

Examples of acids having a pKa of 2 to 5 at 25°C include phosphoric acid, citric acid, acetic acid, propionic acid, ascorbic acid, formic acid, and lactic acid. The pKa is an acid that can be identified by analysis, and can be measured by using an absorption analysis method for the acid. Acid HX in the aqueous solution, based in HX and X ^- two states exist, and may be HX X ^- the difference between the absorption spectrum, measured in aqueous solution of HX and X ^- concentration of, and can be calculated based on the following equation (1) .

The concentration of the acid having a pKa of 2 to 5 at 25°C is preferably 0.05 to 1 mol/L. By setting the concentration to 0.05mol/L, the conductivity can be further improved in a short time. On the other hand, by setting the concentration to 1 mol/L or less, acid does not easily remain on the wiring, and reliability can be improved. Moreover, the concentration can be appropriately adjusted to a desired pH according to the type of acid contained.

In step (2), the liquid temperature of the acidic aqueous solution in contact with the pattern is preferably 40°C to 90°C. By setting the liquid temperature to 40°C or higher, the conductivity can be improved in a shorter time. The liquid temperature is more preferably 60°C or higher. On the other hand, by setting the liquid temperature to 90°C or lower, evaporation of the acidic aqueous solution can be suppressed. Furthermore, the liquid temperature of the acidic aqueous solution can be appropriately adjusted according to the kind of acid contained.

In step (2), the acidic aqueous solution can be heated in advance and then brought into contact with the pattern, or it can be heated while the pattern is in contact with the acidic aqueous solution. Examples of the heating method include heating by a hot plate, hot air oven, inert oven, IR furnace, microwave, etc., xenon flash lamp irradiation, and the like.

The concentration of the acidic aqueous solution is preferably 0.05 to 1 mol/L. By setting the concentration to 0.05mol/L, the conductivity can be further improved in a short time. On the other hand, by setting the concentration to 1 mol/L or less, acid does not easily remain on the wiring, and reliability can be improved. Moreover, the concentration can be appropriately adjusted to a desired pH according to the type of acid contained.

The conductive pattern obtained in step (2) can also be cleaned with a cleaning solution. Here, as the cleaning liquid, for example, water or an aqueous solution obtained by adding alcohols such as ethanol or isopropanol or esters such as ethyl lactate or propylene glycol monomethyl ether acetate to water. The residual acid can be cleaned by cleaning treatment, and the long-term reliability of the wiring can be improved. [Example]

Hereinafter, the present invention will be explained in detail with examples and comparative examples, but the aspects of the present invention are not limited to these.

The materials used in the examples and comparative examples are as follows.

[Conductive particles (a)] Silver particles with a volume average particle size of 0.3μm [Reactive monomer with unsaturated double bond (c)] LIGHT ACRYLATE BP-4EA (acrylic monomer; manufactured by Kyoeisha Chemical Co., Ltd.).

(Synthesis example 1) 5 parts by mass of glycidyl methacrylate (hereinafter referred to as "GMA") and EA/-2-ethylhexyl methacrylate (hereinafter referred to as "2-EHMA")/ Acrylic copolymer of styrene/acrylic acid (copolymerization ratio (parts by mass): 20/40/20/15) for addition reaction In a reaction vessel in a nitrogen atmosphere, 150 g of DMEA described later was fed, and the temperature was raised to 80°C using an oil bath. In it, it took 1 hour to drop a mixture containing 20g of EA, 40g of 2-EHMA, 20g of St, 15g of AA, 0.8g of 2,2'-azobisisobutyronitrile and 10g of DMEA. After the dropping, the polymerization reaction was further carried out for 6 hours. After that, 1 g of hydroquinone monomethyl ether was added to stop the polymerization reaction. Then, it took 0.5 hour to drop a mixture containing 5 g of GMA, 1 g of triethylbenzylammonium chloride, and 10 g of DMEA. After completion of the dropping, the addition reaction was further carried out for 2 hours. The obtained reaction solution was purified with methanol to remove unreacted impurities, and further vacuum-dried for 24 hours, thereby obtaining an acrylic copolymer (B-1). The acid value of the obtained acrylic copolymer (B-1) was 103 mgKOH/g.

(Synthesis example 2) Make 5 parts by mass of GMA and ethylene oxide modified bisphenol A diacrylate (FA-324A; manufactured by Hitachi Chemical Co., Ltd.)/EA/AA acrylic copolymer (copolymerization ratio (parts by mass): 50/10/15) Addition responders In a reaction vessel in a nitrogen atmosphere, 150g of DMEA was fed, and the temperature was raised to 80°C using an oil bath. In it, it took 1 hour to drop 50g of ethylene oxide modified bisphenol A diacrylate FA-324A, 20g of EA, 15g of AA, 0.8g of 2,2'-azobisisobutyronitrile and 10g The mixture of DMEA. After the dropping, the polymerization reaction was further carried out for 6 hours. After that, 1 g of hydroquinone monomethyl ether was added to stop the polymerization reaction. Then, it took 0.5 hour to drop a mixture containing 5 g of GMA, 1 g of triethylbenzylammonium chloride, and 10 g of DMEA. After completion of the dropping, the addition reaction was further carried out for 2 hours. Unreacted impurities were removed by purifying the obtained reaction solution with methanol, and it was further vacuum dried for 24 hours, thereby obtaining an acrylic copolymer (B-2). The acid value of the obtained acrylic copolymer (B-2) was 96 mgKOH/g.

(Synthesis example 3) Acrylic copolymer of EA/2-EHMA/BA/N-methylol acrylamide/AA (copolymerization ratio (parts by mass): 20/40/20/5/15) In a reaction vessel in a nitrogen atmosphere, 150g of DMEA was fed, and the temperature was raised to 80°C using an oil bath. Among them, it took 1 hour to drop the components containing 20g of EA, 40g of 2-EHMA, 20g of BA, 5g of N-hydroxymethacrylamide, 15g of AA, 0.8g of 2,2'-azobisisobutyl Mixture of nitrile and 10g of DMEA. After the dropping, the polymerization reaction was further carried out for 6 hours. After that, 1 g of hydroquinone monomethyl ether was added to stop the polymerization reaction. Unreacted impurities were removed by purifying the obtained reaction solution with methanol, and it was further vacuum-dried for 24 hours, thereby obtaining an acrylic copolymer (B-3). The acid value of the obtained acrylic copolymer (B-3) was 103 mgKOH/g.

[Photopolymerization initiator (d)] "IRGACURE (registered trademark)" OXE01 (trade name, manufactured by BASF Japan Co., Ltd., oxime-based compound) (hereinafter referred to as OXE01).

[Solvent] DMEA (manufactured by Tokyo Chemical Industry Co., Ltd.) The evaluation method of each example and comparative example is as follows.

＜Measurement of pKa＞ The acidic aqueous solution adjusted to the acid described in Table 1 to 0.01 mol/L was maintained at a liquid temperature of 25°C, and the pKa of the acid was measured using a pKa analyzer (Sirius-T3; manufactured by Pion).

After adjusting the acid containing the anion and proton constituting the salt to 0.01 mol/L, the aqueous solution was maintained at a liquid temperature of 25°C, and the conjugate acid of the anion constituting the salt was measured using a pKa analyzer (Sirius-T3; manufactured by Pion) PKa. When the pKa of the conjugate acid constituting the anion of the salt is below -2, please refer to "David A. Evans, [online], Internet <URL: http://evans.rc.fas.harvard.edu/ pdf/evans_pKa_table.pdf>".

＜Measurement of pH＞ The acidic aqueous solution described in Table 1 was maintained at a liquid temperature of 25°C, and the pH of the acidic aqueous solution was measured using a pH meter (F-71; manufactured by Horiba Manufacturing Co., Ltd.).

＜Evaluation of patternability＞ Observe the samples for evaluation of patterning properties obtained in each of the Examples and Comparative Examples with an optical microscope, and confirm that the value of line and space (hereinafter, described as "L/S") is the smallest value The conductive pattern of L/S is judged as A when its L/S value is 7/7, B when it is 10/10, C when it is 15/15, and 15/15 conductive pattern cannot be formed The situation of is judged as D, where there is no residue between the patterns of the conductive pattern and no pattern peeling. The order of excellent patternability is A>B>C>D, indicating that fine patterning is possible.

＜Evaluation of conductivity＞ The respective ends of the samples for evaluating the conductivity obtained in the respective examples and comparative examples were connected with a resistance meter (RM3544; manufactured by HIOKI), the resistance value was measured, and the ratio was calculated based on the following formula (2) Resistivity. In addition, the film thickness is measured using a stylus-type step gauge such as "SURFCOM (registered trademark)" 1400 (manufactured by Tokyo Precision Co., Ltd.). More specifically, it is calculated by measuring the film thickness of 10 randomly selected locations with a stylus-type step gauge (length measurement: 1 mm, scanning speed: 0.3 mm/sec), and obtaining their average value. In addition, the line width is calculated by observing the line widths of 10 randomly selected positions with an optical microscope, analyzing the image data, and obtaining their average value. Specific resistance=resistance value×film thickness×line width/line length...(2) It means that the smaller the specific resistance, the better the conductivity.

(Example 1) In a 100mL clean bottle, place 10.0g of acrylic copolymer (B-1), 2.0g of LIGHT ACRYLATE BP-4EA, 0.60g of OXE01 and 9.0g of DMEA, with "Awatori Rentaro" ( ARE-310; manufactured by THINKY Co., Ltd.) was mixed to obtain 21.6 g of a resin solution (total solid content 58.3% by mass).

21.6 g of the obtained resin solution and 50.4 g of silver particles were mixed and kneaded using a 3-roll mill (EXAKT M-50; manufactured by EXAKT Corporation) to obtain 72.0 g of conductive paste 1.

On a PET film with a thickness of 50 μm, the conductive paste 1 was applied by screen printing to make the coating film thickness after drying 1.5 μm, and the obtained coating film was dried in a drying oven at 80° C. for 15 minutes. The following patterning properties and conductivity were evaluated.

The patterning property is a linear group of a certain L/S arrangement, that is, the light transmission pattern is set to 1 unit, and the dried coating film is processed through a mask with 3 types of units with different L/S values. After exposure and development, 3 patterns with different L/S values were obtained respectively. After that, the three patterns obtained were immersed in the acidic aqueous solution described in Table 1 for a predetermined time, the acid was washed away by ultrapure water, and the water was removed by air cutting. Dry in a drying oven for 3 minutes to obtain 3 kinds of conductive patterns with different values of L/S, which are used as samples for patterning evaluation. In addition, the value of L/S of each unit of the photomask is set to 15/15, 10/10, and 7/7 (representing the respective line width (μm)/interval (μm)). The exposure system uses an exposure device (PEM-6M; manufactured by UNION Optics Co., Ltd.) to perform full-line exposure with an exposure amount of 300mJ/cm ² (converted to a wavelength of 365 nm). The development system immerses the substrate in a 0.20% by mass Na ₂ CO ₃ solution After 30 seconds, it was washed with ultrapure water. Table 1 shows the evaluation results regarding patternability.

Conductivity Expose and develop the dried coating film through a photomask with 100 light-transmitting patterns 100 as shown in FIG. 1 to obtain patterns. After that, the resulting pattern was immersed in the acidic aqueous solution described in Table 1 for the time described in Table 1, the acid was washed away by ultrapure water washing treatment, and the water was removed by air cutting. Dry in a drying oven for 3 minutes to obtain a sample for evaluation of conductivity. The line width of the obtained conductive pattern was 0.10 mm, and the line length was 80 mm. In addition, the conditions of exposure and development are the same as those described in the preparation of the sample for evaluation of patterning properties. Table 1 shows the evaluation results of conductivity.

(Examples 2-24, 26) A predetermined pattern was formed by the conductive paste of the composition shown in Table 1, and the conductive pattern was manufactured in the same manner as in Example 1 using the acidic aqueous solution shown in Table 1, and the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results of patterning properties and conductivity.

(Example 25) Place 12.0g of acrylic copolymer (B-2), 0.60g of OXE01 and 9.0g of DMEA in a 100mL clean bottle, and use "Awatori Rentaro" (ARE-310; manufactured by THINKY Co., Ltd.) ) Mix to obtain 21.6 g of resin solution (total solid content 58.3% by mass).

21.6 g of the obtained resin solution and 50.4 g of silver particles were mixed and kneaded using a 3-roll mill (EXAKT M-50; manufactured by EXAKT Corporation) to obtain 72.0 g of conductive paste 2. A predetermined pattern was formed by the conductive paste 2, and the acidic aqueous solution shown in Table 1 was used to produce a conductive pattern in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results of patterning properties and conductivity.

(Example 27) The conductive paste with the composition shown in Table 1 was used to form a predetermined pattern, and the resulting pattern was immersed in the acidic aqueous solution shown in Table 1 for the time shown in Table 1, and then dried at 100°C without washing. The oven is cured for 10 minutes. Thereafter, the acid was washed away by washing with ultrapure water, and the water was removed by air cutting, and dried in a drying oven at 80° C. for 3 minutes to produce a conductive pattern, and the same evaluation as in Example 1 was performed. Table 1 shows the evaluation results of patterning properties and conductivity.

(Example 28) Place 10.0 g of acrylic copolymer (B-1) and 8.0 g of DMEA in a 100 mL clean bottle, and mix with "Awatori Rentaro" (ARE-310; manufactured by THINKY Co., Ltd.) to obtain 18.0 g resin solution (total solid content 55.6% by mass).

18.0 g of the obtained resin solution and 90.0 g of silver particles were mixed and kneaded using a 3-roll mill (EXAKT M-50; manufactured by EXAKT Corporation) to obtain 108.0 g of conductive paste 3.

On a PET film with a thickness of 50 μm, the conductive paste 3 was printed by gravure printing to obtain three patterns with different L/S values. The resulting pattern was dried in a drying oven at 80°C for 15 minutes. After that, the three patterns obtained were immersed in the acidic aqueous solution described in Table 1 for a predetermined time, the acid was washed away by ultrapure water, and the water was removed by air cutting. Dry in a drying oven for 3 minutes to obtain 3 kinds of conductive patterns with different values of L/S, which are used as samples for patterning evaluation. In addition, the value of L/S of each unit of the intaglio plate used in gravure printing is set to 15/15, 10/10, and 7/7 (representing the respective line width (μm)/space (μm)). Table 1 shows the evaluation results regarding patternability.

The conductive paste 3 was printed on a PET film with a thickness of 50 μm by gravure printing to obtain a pattern for evaluating the conductivity. The intaglio plate used in gravure printing has 100 patterns 100 as shown in FIG. 1. The resulting pattern was dried in a drying oven at 80°C for 15 minutes. After that, the resulting pattern was immersed in the acidic aqueous solution described in Table 1 for the time described in Table 1, the acid was washed away by ultrapure water washing treatment, and the water was removed by air cutting. Dry in a drying oven for 3 minutes to obtain a sample for evaluation of conductivity. The line width of the obtained conductive pattern was 0.10 mm, and the line length was 80 mm. Table 1 shows the evaluation results of conductivity.

(Comparative Examples 1, 2, 6-9) The conductive paste of the composition shown in Table 2 was used to form a predetermined pattern, the acidic aqueous solution shown in Table 2 was used to produce a conductive pattern in the same manner as in Example 1, and the same evaluation as in Example 1 was performed. Table 2 shows the evaluation results of patterning properties and conductivity.

(Comparative example 3) The conductive paste with the composition shown in Table 2 was used to form a predetermined pattern, the resulting pattern was immersed in a 0.2mol/L hydrochloric acid aqueous solution at 25°C for 1 minute, and then immersed in a 0.2mol/L solution heated to 70°C. The citric acid aqueous solution of L was washed with ultrapure water for 5 minutes, the acid was washed away, and the water was removed by air cutting, and dried in a drying oven at 80°C for 3 minutes to produce a conductive pattern, which was the same as in Example 1. The evaluation. Table 2 shows the evaluation results of patterning properties and conductivity.

(Comparative Example 4) A conductive paste with the composition shown in Table 2 was used to form a predetermined pattern, the resulting pattern was immersed in a 0.2mol/L hydrochloric acid aqueous solution at 25°C for 1 minute, and then immersed in a 0.2mol/L solution heated to 70°C. The citric acid aqueous solution of L was washed with ultrapure water for 10 minutes, the acid was washed away by air cutting, and the water was removed by air cutting. The conductive pattern was produced by drying in a drying oven at 80°C for 3 minutes, and proceeded as in Example 1. The evaluation. Table 2 shows the evaluation results of patterning properties and conductivity.

(Comparative Example 5) The conductive paste with the composition shown in Table 2 was used to form a predetermined pattern. The resulting pattern was immersed in a 1 mol/L hydrochloric acid aqueous solution at 25°C for 1 minute, and then immersed in a 1 mol/L solution heated to 70°C. The citric acid aqueous solution was washed with ultrapure water for 10 minutes, the acid was washed away by air cutting, and the water was removed by air cutting. The conductive pattern was produced by drying in a drying oven at 80°C for 3 minutes, and the same evaluation as in Example 1 was performed. . Table 2 shows the evaluation results of patterning properties and conductivity.

(Comparative Example 10) A conductive paste with the composition shown in Table 2 was used to form a predetermined pattern, without immersing in an acidic aqueous solution, the resulting pattern was cured in a drying oven at 100°C for 1 hour to produce a conductive pattern, and the same evaluation as in Example 1 was performed . Table 2 shows the evaluation results of patterning properties and conductivity.

[Table 1] Conductive paste composition Acidic aqueous solution treatment Evaluation results Resin (b) salt Acid other than salt PH at 25°C Dipping condition Acrylic copolymer species species The pKa of conjugate acid of anion at 25℃ concentration species PKa at 25℃ concentration Liquid temperature Processing time Patternability Specific resistance (Ω・cm) Example 1 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 4.5×10 ^-5 Example 2 B-1 Sodium trifluoroacetate 0.2 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 9.5×10 ^-5 Example 3 B-1 Sodium nitrate -1.4 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 8.7×10 ^-5 Example 4 B-1 Nickel(II) chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 4.8×10 ^-5 Example 5 B-1 Potassium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 5.5×10 ^-5 Example 6 B-1 Sodium bromide -9.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 4.4×10 ^-5 Example 7 B-1 Sodium bisulfate -3.0 0.1mol/L no 1.6 70℃ 5min A 8.2×10 ^-5 Example 8 B-1 Sodium Iodide -10.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 4.3×10 ^-5 Example 9 B-1 Iron(III) chloride -8.0 0.1mol/L no 1.8 70℃ 5min A 5.2×10 ^-5 Example 10 B-1 Sodium chloride -8.0 0.02mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 30min A 1.1×10 ^-4 Example 11 B-1 Sodium chloride -8.0 0.05mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 10min A 7.5×10 ^-5 Example 12 B-1 Sodium chloride -8.0 0.2mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 4.3×10 ^-5 Example 13 B-1 Sodium chloride -8.0 0.5mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A 4.0×10 ^-5 Example 14 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 25℃ 30min A 1.2×10 ^-4 Example 15 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 40℃ 30min A 9.5×10 ^-5 Example 16 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 90℃ 3min A 4.0×10 ^-5 Example 17 B-1 Sodium chloride -8.0 0.1mol/L Phosphoric acid 2.2 0.2mol/L 1.5 70℃ 5min A 5.6×10 ^-5 Example 18 B-1 Sodium chloride -8.0 0.1mol/L ascorbic acid 4.2 0.2mol/L 2.4 70℃ 5min A 8.7×10 ^-5 Example 19 B-1 Sodium chloride -8.0 0.1mol/L acetic acid 4.8 0.2mol/L 2.7 70℃ 60min A 1.1×10 ^-4 Example 20 B-1 Sodium chloride -8.0 0.1mol/L Trifluoroacetic acid 0.2 0.01mol/L 2.0 70℃ 5min A 8.5×10 ^-5 Example 21 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.01mol/L 2.6 70℃ 30min A 1.0×10 ^-4 Example 22 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.05mol/L 2.2 70℃ 30min A 8.2×10 ^-4 Example 23 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.1mol/L 2.1 70℃ 10min A 6.8×10 ^-5 Example 24 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.5mol/L 1.7 70℃ 2min A 4.2×10 ^-5 Example 25 B-2 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min C 6.5×10 ^-5 Example 26 B-3 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min B 6.1×10 ^-5 Example 27 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 25℃ 1min A 6.2×10 ^-5 Example 28 B-1 Sodium chloride -8.0 0.1mol/L Citric acid 3.1 0.2mol/L 1.9 70℃ 5min C 2.1×10 ^-5

[Table 2] Conductive paste composition Acidic aqueous solution treatment Evaluation results Conductive particles (a) ＜Ag＞ salt Acid other than salt PH at 25°C Dipping condition Proportion in the conductive pattern (mass%) species The pKa of conjugate acid of anion at 25℃ concentration species PKa at 25℃ concentration Liquid temperature Processing time Patternability Specific resistance (Ω・cm) Comparative example 1 80 No salt Citric acid 3.1 0.2mol/L 1.9 70℃ 5min A Unable to determine Comparative example 2 80 No salt Citric acid 3.1 0.2mol/L 1.9 70℃ 30min A Unable to determine Comparative example 3 80 No salt Citric acid hydrochloride -8.0 3.1 0.2mol/L 0.2mol/L 0.7 1.9 25℃ 70℃ 1min 5min A 5.3×10 ^-4 Comparative example 4 80 No salt Citric acid hydrochloride -8.0 3.1 0.2mol/L 0.2mol/L 0.7 1.9 25℃ 70℃ 1min 10min A 4.6×10 ^-4 Comparative example 5 80 No salt Citric acid hydrochloride -8.0 3.1 1mol/L 1mol/L 0.0 1.6 25℃ 70℃ 1min 10min A 1.2×10 ^-3 Comparative example 6 80 Sodium chloride -8.0 0.1mol/L Acid free 7 70℃ 5min A 8.5×10 ^-2 Comparative example 7 80 Sodium chloride -8.0 0.1mol/L acetic acid 4.8 0.002mol/L 3.8 70℃ 60min A 1.2×10 ^-3 Comparative example 8 80 Sodium chloride -8.0 0.1mol/L hydrochloric acid -8.0 1mol/L 0.0 70℃ 5min A 1.0×10 ^-3 Comparative example 9 80 Sodium dihydrogen phosphate 2.2 0.1mol/L Citric acid 3.1 0.2mol/L 2.0 70℃ 60min A Unable to determine Comparative example 10 80 No salt and acid, heat treatment in air at 100℃ for 60min A Unable to determine

100: light transmission pattern

FIG. 1 is a schematic diagram of the light transmission pattern of the photomask used in the evaluation of the conductivity in the embodiment.

no.

Claims (8)

A manufacturing method of conductive pattern, which has: (1) A step of forming a pattern on a substrate, the pattern including conductive particles (a) and resin (b); and (2) The step of contacting the formed pattern with an acidic aqueous solution with a pH of 1.2 to 3.5 at 25°C, the acidic aqueous solution containing at least one anion at 25°C, and the acid dissociation constant (pKa) of the conjugate acid is 1.0 or less Of salt. The method for manufacturing a conductive pattern according to claim 1, wherein the concentration of the salt contained in the acidic aqueous solution is 0.05 mol/L or more. The method for producing a conductive pattern according to claim 1 or 2, wherein the acidic aqueous solution contains an acid other than the salt, and the acid has a pKa of 2-5. The method for manufacturing a conductive pattern according to any one of claims 1 to 3, wherein the liquid temperature of the acidic aqueous solution is 40°C to 90°C. The method for manufacturing a conductive pattern according to any one of claims 1 to 4, which is heated in a state where the pattern is in contact with the acidic aqueous solution. The method for manufacturing a conductive pattern according to any one of claims 1 to 5, wherein the step of forming the pattern in (1) is to form a coating film by coating a photosensitive paste on a substrate, and by forming the coating film Exposure and development to form a patterned photoetching step, wherein the photosensitive paste contains: conductive particles (a), carboxyl-containing resin (B), reactive monomers with unsaturated double bonds (c), and photopolymerization Starter (d). The method for manufacturing a conductive pattern according to any one of claims 1 to 6, wherein the conductive particles (a) contain silver particles. The method for manufacturing a conductive pattern according to any one of claims 1 to 7, wherein the thickness of the conductive pattern is 3 μm or less.

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