JPH11249299A - Photosensitive dispersed matter, photosensitive sheet and manufacture of conductive pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of forming conductive pattern such as a wiring pattern of high reliability and an excellent electrical connection part between electrodes using a photosensitive composition containing conductive grains. SOLUTION: A conductive pattern manufacturing method comprises a process of providing a photosensitve layer, formed by dispersing conductive grains covered with a low temperature decomposable polymer decomposed at the temperature in a range of 140-280 deg.C, in a composition containing a photopolymerized compound formed in sheet shape and a photopolymerization initiator, on a conductive board, a process of exposing the photosensitive layer in a pattern state, a process of developing the exposed photosenstive layer to obtain a pattern-like hardened layer formed of the exposed part of the photosensitive layer, and a process of heating the pattern-like hardened layer to the temperature of 140 deg.C or higher to decompose the low temperature decomposable polymer around the conductive grains. Photosensitive dispersed matter and a photosensitive sheet can be advantageously used to manufacture the conductive pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a photosensitive dispersion, a photosensitive sheet, and a method for producing a conductive pattern.
More specifically, the present invention relates to an advantageous method for producing a conductive pattern represented by a conductive circuit, and a photosensitive dispersion and a photosensitive sheet that can be advantageously used in the method for producing the conductive pattern.

[0002]

2. Description of the Related Art In a liquid crystal display device, an image reading device, and the like, which have been developed in recent years, there is a high demand for a high density of an electric circuit. Therefore, a high density wiring pattern is formed and a high density connection between electrodes is required. Research is being carried out for realization.

Japanese Patent Application Laid-Open No. 8-62617 discloses a method using a conductive photosensitive resin composition in which conductive fine particles are dispersed in a photosensitive resin for high-density electrical connection between electrodes. ing. According to this publication, the conductive photosensitive resin composition is coated on the surface of an electrode formed on a substrate, irradiated with light, and developed to selectively form a conductive region. It is stated that high-density electrical connection between the electrodes is possible by aligning and connecting a separately prepared substrate with electrodes to the surface of the conductive region.

[0004]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 8-626 is disclosed.
As described in JP-A No. 17, a method using a photosensitive resin composition containing conductive particles is already known as a high-density electrical connection method between electrodes. The method of using the photosensitive resin composition containing such conductive particles is such that the working process is simple for the purpose of making high-density connection between electrodes or forming a high-density electric circuit. Therefore, it can be said that this method is advantageous for industrial use. However, according to the study of the present inventor, it has been found that the formed layer containing the conductive particles does not easily exhibit sufficient conductivity.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a photosensitive resin composition containing conductive particles which enables good electrical connection between electrodes with high reliability. The present invention also provides a method for forming a conductive pattern such as a highly reliable wiring pattern or a good electrical connection between electrodes using a photosensitive resin composition containing conductive particles. The purpose is also.

[0006]

SUMMARY OF THE INVENTION The present invention provides a conductive polymer coated with a low-temperature decomposable polymer which decomposes at a temperature in the range of 140 to 280 ° C. in a solution containing a photopolymerizable compound and a photopolymerization initiator. In a photosensitive dispersion obtained by dispersing conductive particles.

According to the present invention, there is also provided a method for forming conductive particles coated with a low-temperature decomposable polymer which decomposes at a temperature in the range of 140 to 280 ° C. into a sheet containing a photopolymerizable compound and a photopolymerization initiator. There is also a photosensitive sheet dispersed in the prepared composition.

[0008] The present invention also provides a method for fabricating 140 non-conductive substrates.
Conductive particles coated with a low-temperature decomposable polymer that decomposes at a temperature in the range of ２280 ° C. are dispersed in a fat composition containing a photopolymerizable compound and a photopolymerization initiator formed in a sheet shape. Providing a photosensitive layer comprising: exposing the photosensitive layer in a pattern; developing the exposed photosensitive layer to obtain a patterned cured layer composed of exposed portions of the photosensitive layer; and A temperature of 140 ° C. or higher, preferably a temperature in the range of 140 to 280 ° C.,
The method also comprises a step of decomposing the low-temperature decomposable polymer around the conductive particles by heating the conductive pattern.

The conductive particles used in the present invention are preferably carbon black. Further, the low-temperature decomposable polymer preferably has a polar group such as a carboxylic acid group or a carboxylic acid group in its molecular structure. And it is desirable that the photosensitive composition and the photosensitive sheet of the present invention further use a binder. As the binder, it is preferable to use the above-mentioned low-temperature decomposable polymer or a mixture of the low-temperature decomposable polymer and another polymer.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A method for producing a photosensitive dispersion containing a conductive particle, a photosensitive sheet, and a conductive pattern according to the present invention will be described.

The photosensitive dispersion of the present invention is a conductive dispersion coated with a low-temperature decomposable polymer which decomposes at a temperature in the range of 140 to 280 ° C. in a solution containing a photopolymerizable compound and a photopolymerization initiator. Obtained by dispersing particles.

The photopolymerizable compound used in the present invention is preferably a monomer having an ethylenically unsaturated double bond and capable of undergoing addition polymerization upon irradiation with light. Examples of such a monomer include compounds having at least one addition-polymerizable ethylenically unsaturated group in the molecule and having a boiling point of 100 ° C. or more at normal pressure. Examples thereof include monofunctional acrylates and monofunctional methacrylates such as polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate and phenoxyethyl (meth) acrylate; polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate. ) Acrylate, trimethylolethane triacrylate, trimethylolpropane triacrylate, trimethylolpropane diacrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (Meth) acrylate, dipentaerythritol penta (meth) acrylate, hexanediol (Meth) acrylate, trimethylolpropane tri (acryloyloxypropyl) ether, tri (acryloyloxyethyl) isocyanurate, tri (acryloyloxyethyl) cyanurate, glycerin tri (meth) acrylate; polyfunctional alcohols such as trimethylolpropane and glycerin And polyfunctional acrylates and polyfunctional methacrylates obtained by adding propylene oxide to ethylene oxide and then (meth) acrylated. Furthermore, Japanese Patent Publication No. 48-41708
JP, JP-B-50-6034 and JP-A-51-
Urethane acrylates described in JP 37193; JP-A-48-64183, JP-B-49-4
Polyester acrylates described in JP-A-3191 and JP-B-52-30490; polyfunctional acrylates and methacrylates such as epoxy acrylates which are reaction products of an epoxy resin and (meth) acrylic acid. Among these, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and dipentaerythritol penta (meth) acrylate are preferred. These monomers may be used alone or in combination of two or more kinds. The content of the photosensitive dispersion with respect to the total solid content is 5%.
It is generally from 50 to 50% by weight, and preferably from 10 to 40% by weight.

The photopolymerization initiator used in the present invention includes a vicinal polyketaldonyl compound disclosed in US Pat. No. 2,367,660 and US Pat.
No. 8828, an acyloin ether compound described in US Pat. No. 2,722,512.
-Aromatic acyloin compounds substituted with hydrocarbons, U.S. Pat. Nos. 3,046,127 and 2,951,758
Quinone compounds described in U.S. Pat.
No. 9367, a combination of a triarylimidazole dimer and a p-aminoketone, JP-B-51-485.
No. 16 benzothiazole compound and trihalomethyl-s-triazine compound described in U.S. Pat.
Examples thereof include a trihalomethyl-s-triazine compound described in Japanese Patent No. 50, and a trihalomethyloxadiazole compound described in US Pat. No. 4,221,976. In particular, trihalomethyl-s-
Triazine, trihalomethyloxadiazole and triarylimidazole dimers are preferred. The content of the photopolymerization initiator with respect to the total solid content of the photosensitive dispersion is 0.5 to
20% by weight is common and 1-15% by weight is preferred.

In the photosensitive dispersion of the present invention, since the low-temperature decomposable polymer used for coating the conductive particles also functions as a binder at the time of forming the photosensitive sheet, it is not always necessary to prepare a separate binder. However, in order to produce a photosensitive sheet having a sufficient self-supporting property, it is preferable to use a binder in combination.

The binder is not particularly limited, and a usual film-forming polymer can be used.
However, a polymer having a decomposition temperature of 140 to 280 ° C. and having a polar group such as a carboxylic acid group or a carboxylate group in a side chain is advantageously used as the binder in the present invention. Examples thereof include low-temperature decomposable polymers that can be used for coating the conductive particles described below. These binder polymers having a polar group may be used alone or in the form of a composition used in combination with a usual film-forming polymer.

The above-mentioned binder preferably has low-temperature decomposability such that it decomposes at a temperature in the range of 140 to 280 ° C.

Examples of the conductive particles used in the present invention include:
Particles of gold, copper, nickel, carbon black, carbon fiber, zinc oxide, barium sulfate and aluminum borate whiskers coated with tin oxide, tin oxide / antimony oxide composite oxide, and indium oxide / tin oxide composite oxide And metal-plated plastic particles such as acrylic and polystyrene. Particularly preferred is carbon black. The conductive particles preferably have an average particle size in the range of 0.001 to 1 μm in consideration of the dispersion stability. The amount of the conductive particles is preferably in the range of 10 to 80% by weight based on all solid components of the photosensitive dispersion. Note that in the case where particles which do not hinder light transmission need to be used as the conductive particles, particles having low light absorption in a wavelength region of 400 to 700 nm are preferably used.

The conductive particles, which are dispersions of the photosensitive dispersion of the present invention, are characterized in that they are coated with a low-temperature decomposable polymer which decomposes at a temperature in the range of 140 to 280 ° C. This coating polymer is a polymer having a function of enhancing the dispersion stability of the conductive particles in the photosensitive dispersion and preventing aggregation and precipitation of the conductive particles. Therefore, this coating polymer is preferably a polymer having a polar group such as a carboxylic acid group or a carboxylic acid group in the side chain.
Examples thereof include JP-A-59-44615, JP-B-54-34327, JP-B-58-12577, JP-B-54-25959, and JP-A-59-5.
No. 3836, and methacrylic acid copolymer, acrylic acid copolymer, itaconic acid copolymer, crotonic acid copolymer, maleic acid copolymer as described in JP-A-59-71048, A partially esterified maleic acid copolymer can be used. Further, a cellulose derivative having a carboxylic acid group in a side chain can also be mentioned. In addition, those obtained by adding a cyclic acid anhydride to a polymer having a hydroxyl group can also be preferably used. In particular, benzyl (meth) described in U.S. Pat. No. 4,139,391.
Copolymers of acrylate and (meth) acrylic acid and multi-component copolymers of benzyl (meth) acrylate, (meth) acrylic acid and other monomers can be mentioned.

The photosensitive dispersion of the present invention preferably further contains a thermal polymerization inhibitor in addition to the above components. Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, di-t-butyl-p-cresol, pyrogallol, t-butylcatechol, benzoquinone, 4,4′-
Thiobis (3-methyl-6-t-butylphenol),
2,2'-methylenebis (4-methyl-6-t-butylphenol), 2-mercaptobenzimidazole, phenothiazine and the like.

Further, known additives such as a plasticizer, a surfactant and a solvent can be added to the photosensitive dispersion of the present invention, if necessary.

The photosensitive dispersion of the present invention is prepared by dissolving or dispersing the above solid components in a solvent. This photosensitive dispersion is used as a coating liquid to form a photosensitive resin composition layer on the surface of a temporary support, a substrate, or the like.

Examples of the solvent used for preparing the photosensitive dispersion include methyl ethyl ketone, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, cyclohexanone, cyclohexanol, ethyl lactate, methyl lactate, caprolactam and the like. .

The photosensitive dispersion of the present invention can be applied to the surface of a substrate or a temporary support by a known method and dried to form a photosensitive sheet. Note that the photosensitive sheet can be used as a photosensitive layer formed on a substrate or as an independent sheet after the photosensitive layer is once peeled off.

The application of the photosensitive dispersion is carried out, for example, by using a spinner,
The coating is performed using a coating machine such as a wiper, a roller coater, a curtain coater, a knife coater, a wire bar coater, and an extruder. The formed coating layer is then dried to obtain a photosensitive layer or a photosensitive sheet.

The photosensitive sheet of the present invention can be formed by applying a coating solution of the above composition and drying. The photosensitive sheet of the present invention is particularly in the form of a photosensitive transfer material (photosensitive transfer sheet) in which a photosensitive resin composition layer is provided on a temporary support in the form of a sheet made of a flexible material. Is preferably used.

The photosensitive transfer material should be constructed so as to have basically the same configuration as a known photosensitive transfer material except that the above-mentioned photosensitive resin composition is used as the photosensitive resin material. Can be. An example of the constitution of a known photosensitive transfer material is described in JP-A-5-173320. The simplest structure of the photosensitive transfer material is on a support sheet made of a flexible plastic film, etc.
Although a thin layer made of a photosensitive resin composition is formed, a layer for facilitating separation between the support sheet and the photosensitive resin composition layer, a photosensitive resin composition layer An undercoat layer or an intermediate layer such as a layer serving as a cushion can be optionally provided. As an example of a preferable configuration, a configuration in which an alkali-soluble thermoplastic resin layer, an intermediate layer, and a photosensitive resin composition layer are formed on a support sheet can be given. In addition, a protective film is arbitrarily laminated on the photosensitive layer (photosensitive resin composition layer).

Next, a method for manufacturing a conductive pattern according to the present invention will be described. The method of manufacturing a conductive pattern according to the present invention is characterized in that the following steps are sequentially performed. (1) Conductive particles coated on a non-conductive substrate with a low-temperature decomposable polymer that decomposes at a temperature in the range of 140 to 280 ° C. start photopolymerization with a photopolymerizable compound formed in a sheet shape. Providing a photosensitive layer dispersed in a resin composition containing an agent; (2) exposing the photosensitive layer in a pattern; and (3) developing the exposed photosensitive layer to form a photosensitive layer. Obtaining a patterned cured layer composed of exposed portions of the layer; and (4) heating the patterned cured layer to a temperature of 140 ° C. or higher to remove the low-temperature decomposable polymer around the conductive particles. The process of decomposing.

The above step (1) may be carried out by directly applying a photosensitive dispersion on the surface of a substrate (a glass plate, a plastic sheet, a glass fiber reinforced plastic sheet, etc.) and drying it. A method in which a photosensitive layer is formed on a separately prepared temporary support (a sheet made of a flexible plastic material) to form a photosensitive sheet, and the photosensitive layer of the photosensitive sheet is transferred to a substrate surface. Is preferred.

The above-mentioned photosensitive layer is then subjected to a step of patternwise exposing by imagewise exposure using a photomask or the like, that is, step (2). Next, light irradiation is performed using a developing solution. A development step for eluting and removing the portion that has not been subjected, that is, step (3) is performed. In this way, a patterned cured layer corresponding to the exposed portion of the photosensitive layer can be obtained on the substrate.

The above steps (1) to (3) are generally used in an image forming method using a photosensitive transfer material, and are described, for example, in JP-A-5-173320. As a typical image forming method, a photosensitive resin composition layer of a photosensitive transfer material is overlaid on the surface of a material to be transferred (such as a transparent substrate provided on a liquid crystal display element), and the support sheet is peeled off. Subjecting the photosensitive resin composition layer on the material to be transferred to pattern exposure through a photomask.
A method in which a step of heating at a temperature in the range of 180 ° C. to 180 ° C. and a step of dissolving and removing an unexposed portion by developing treatment can be used.

The image forming method (a method for producing a conductive pattern) according to the present invention comprises the steps of:
By heating to a temperature of 40 ° C. or higher (preferably a temperature in the range of 140 to 280 ° C.), when a low-temperature decomposable polymer around the conductive particles is used, and when a low-temperature decomposable polymer is also used as a binder, And the step of decomposing the binder portion, that is, the step (4) is performed. That is, those low-molecular compounds generated when a normal low-molecular compound or a polymer is used as a dispersant for protecting the dispersed state of the conductive particles in the dispersion or a binder (binder) for the photosensitive layer. Insufficiency of contact between conductive particles due to the presence of a polymer or the like, in the present invention, a low-temperature decomposable polymer is used as a coating material for the conductive particles, and more preferably, the low-temperature decomposable polymer is also used as a binder To secure the dispersion stability of the conductive particles in the dispersion liquid, and then secure the moldability and physical strength of the photosensitive layer, and then set the cured pattern layer corresponding to an image-like pattern such as a conductive pattern. After forming the cured pattern layer, by heating the cured pattern layer at a temperature equal to or higher than the decomposition temperature of the low-temperature decomposable polymer, the coating layer of the conductive particles and, if desired, a part of the cured pattern layer are also formed. And the solution removed by increasing the contact between the conductive particles is obtained by solving.

The heat treatment of the cured pattern layer may be performed under pressure or may be performed after the pressure treatment.

[0033]

EXAMPLES Example 1 (1) Preparation of Photosensitive Transfer Sheet A coating solution having the composition shown in Table 1 below was applied to a temporary support of a 100 μm-thick polyethylene terephthalate film, followed by drying. A thermoplastic resin layer having a dry film thickness of 20 μm was formed.

[0034]

[Table 1] Table 1 Composition of coating liquid for forming thermoplastic resin layer Methyl methacrylate / 2-ethylhexyl acrylate / benzyl methacrylate / methacrylic acid copolymer (copolymer composition ratio (molar ratio) = 55 / 28.8 / 11.7 / 4.5, weight average molecular weight = 90000 15 parts by weight polypropylene glycol Diacrylate (average molecular weight = 822) 6.5 parts by weight Tetraethylene glycol dimethacrylate 1.5 parts by weight p-toluenesulfonic acid amide 0.5 parts by weight Benzophenone 1.0 parts by weight Methyl ethyl ketone 30 parts by weight ────────────────────────────

Next, a coating liquid having the composition shown in the following Table 2 was applied on the thermoplastic resin layer and dried, and the dried film thickness was 1.6.
A μm intermediate layer was provided.

[0036]

[Table 2] Composition of coating liquid for forming intermediate layer ポ リ ビ ニ ル Polyvinyl alcohol (PVA205 manufactured by Kuraray Co., Ltd., saponification ratio = 80%) 130 parts by weight Polyvinylpyrrolidone (PVP, K-90 manufactured by GAF Corporation) 60 parts by weight Fluorinated surfactant (Surflon S-131 manufactured by Asahi Glass Co., Ltd.) 10 Parts by weight distilled water 3350 parts by weight ──────────────────────────────────

On a temporary support having the above-mentioned thermoplastic resin layer and intermediate layer, a coating solution for forming a photosensitive resin layer having the composition shown in Table 3 below was applied and dried to obtain a photosensitive film having a dry film thickness of about 8 μm. Form a resin layer. Further, a protective sheet of polypropylene (thickness: 12 μm) was pressed on the photosensitive resin layer to prepare a photosensitive transfer material.

[0038]

[Table 3] Table 3 Composition of coating solution for forming black photosensitive resin layer ─ Acrylic acid / benzyl methacrylate copolymer (acrylic acid / benzyl methacrylate = 27/73 (molar ratio), weight average molecular weight 30,000, decomposition temperature 170 ° C.) 26 parts by weight polyfunctional acrylate (DPHA: manufactured by Nippon Kayaku Co., Ltd.) 27 parts by weight Carbon black 45 parts by weight Fluorinated surfactant (F177P: manufactured by Dainippon Ink and Chemicals, Inc.) 0.1 part by weight 2,4-bis (trichloromethyl) [4- (N, N-diethoxy) Carbomethyl) bromophenyl] -s-triazine 1 part by weight Hydroquinone monomethyl ether 0.02 parts by weight Methyl ethyl ketone 240 parts by weight Propylene glycol monomethyl ether Acetate 160 parts by weight ──────────────────────────────────

(2) Production of Conductive Pattern After removing the protective film from the photosensitive layer side surface of the photosensitive transfer sheet, the surface is placed on a 1.1 mm thick glass substrate by a first laminator (VP200, Taisei). Under pressure (10 kg / cm) using a laminator
It was bonded by heating (130 ° C.) and subsequently peeled off at the interface between the temporary support and the thermoplastic resin to remove the temporary support. Next, the surface of the photosensitive layer on the substrate is
Pattern exposure at 00 mj / cm, followed by an alkaline developer (TPD and TCD: Fuji Photo Film Co., Ltd.)
Unnecessary portions were removed, and a conductive pattern-shaped cured layer was formed on a glass substrate. Next, this cured layer was subjected to a heat treatment at 220 ° C. for 2 hours. The volume resistance of the conductive pattern calculated from the surface resistance of the obtained conductive pattern was about 3 Ω · m.

Comparative Example 1 Using the photosensitive transfer sheet prepared in Example 1, a conductive pattern was formed in the same manner as in Example 1 except that the heat treatment after the formation of the cured pattern was not performed. The volume resistance of the conductive pattern calculated from the surface resistance of the obtained conductive pattern was 10 ⁵ Ω · m or more.

Comparative Example 2 In preparing the photosensitive transfer sheet of Example 1, a styrene / maleic anhydride copolymer (styrene / anhydride) was used instead of the acrylic acid / benzyl methacrylate copolymer having a decomposition temperature of 170 ° C. Maleic acid = 5
A conductive pattern was prepared in the same manner as in Example 1 except that a benzylamine modified product having a 0/50 (molar ratio), a weight average molecular weight of 30,000 and a decomposition temperature of 240 ° C. or more) was used.
The volume resistance of the conductive pattern calculated from the surface resistance of the obtained conductive pattern was 10 ⁵ Ω · m or more.

[0042]

By using the photosensitive dispersion or the photosensitive sheet containing the conductive particles of the present invention, electrical characteristics such as a highly reliable wiring pattern and a good electrical connection between electrodes can be obtained. An excellent conductive pattern can be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H05K 3/10 H05K 3/10 C

Claims (11)

[Claims] 1. A photosensitive method comprising dispersing, in a solution containing a photopolymerizable compound and a photopolymerization initiator, conductive particles coated with a low-temperature decomposable polymer that decomposes at a temperature in the range of 140 to 280 ° C. Dispersion. 2. The photosensitive dispersion according to claim 1, wherein the conductive particles are carbon black. 3. The photosensitive dispersion according to claim 1, wherein the low-temperature decomposable polymer has a polar group in its molecular structure. 4. The photosensitive dispersion according to claim 1, further comprising a binder in the solution. 5. The conductive particles coated with a low-temperature decomposable polymer that decomposes at a temperature in the range of 140 to 280 ° C.,
A photosensitive sheet dispersed in a sheet-shaped composition containing a photopolymerizable compound and a photopolymerization initiator. 6. The photosensitive sheet according to claim 5, wherein the conductive particles are carbon black. 7. The photosensitive sheet according to claim 5, wherein the low-temperature decomposable polymer has a polar group in its molecular structure. 8. The photosensitive sheet according to claim 5, further comprising a binder in the composition. 9. A photopolymerizable compound formed on a non-conductive substrate and coated with a low-temperature decomposable polymer that decomposes at a temperature in the range of 140 to 280 ° C. Providing a photosensitive layer dispersed in a composition containing a polymerization initiator; exposing the photosensitive layer in a pattern; developing the exposed photosensitive layer to form a photosensitive layer; Obtaining a patterned hardened layer constituted; and heating the patterned hardened layer to a temperature of 140 ° C. or higher to decompose the low-temperature decomposable polymer around the conductive particles. A method for producing a conductive pattern. 10. The low-temperature decomposable polymer of the photosensitive layer,
The method for producing a conductive pattern according to claim 9, having a polar group in its molecular structure. 11. The method for producing a conductive pattern according to claim 9, wherein the composition for forming the photosensitive layer further contains a binder.