JP2000154354A - Conductive layer transfer sheet, its transfer method, and electric part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an electric part, etc., capable of forming a conductive layer, such as inner electrodes, having excellent thinness, capable of inhibiting bulkiness based on the conductive layer due to the formation of multiple layers, capable of inhibiting the deformation of a flexible sheet laminate due to its surface unevenness caused by the integrated thickness, even when the circuit patterns of upper and lower layers, etc., overlap, hardly generating cracks, etc., even when a ceramic green sheet is laminated, and generally enabling the realization of multi- layered laminates having the number of laminated layers larger than those of conventional laminates. SOLUTION: This conductive layer transfer sheet has a <=1 μm thick transfer film 1 containing at least a conductive layer on an adhesive layer 2 whose adhesive force is reduced when being heated. The method for transferring a conductive layer comprises adhering the sheet to an adherend, heating the sheet to reduce the adhesive force of the adhesive layer, and then peeling the transfer sheet to transfer the transfer film to the adherend. An electric part having the <=1 μm thick transfer film 1 containing at least a conductive layer is formed by the transfer method. Thereby, the extremely thin conductive layer, etc., can efficiently be formed on a curved surface, etc., by a simple operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive layer transfer sheet which can efficiently form a circuit pattern and the like excellent in thinness and is suitable for production of a multilayer ceramic capacitor and a multilayer wiring board, a transfer method therefor, and application of the method. Electrical components.

[0002]

BACKGROUND OF THE INVENTION With respect to electrical components such as multilayer ceramic capacitors and multilayer wiring boards, further multilayering is being studied for the purpose of higher performance and higher capacity. Incidentally, a multilayer ceramic capacitor in which ceramic green sheets provided with internal electrodes are stacked and fired to form chips is considered to have a multilayer structure of 50 layers or more, especially 100 layers or more.

[0003] However, the conventional manufacturing method has a problem that it is difficult to increase the number of layers as compared with the current one due to bulkiness and the like.
That is, for example, in the manufacture of a multilayer ceramic capacitor, conventionally, a ceramic green sheet having a thickness of about 10 μm was formed by a reverse roll method, a slurry printing method, or the like, and the internal electrodes were printed thereon by a screen printing method, a gravure printing method, or the like. A method of stacking sheets is employed. However, in such a conventional method, it is difficult to reduce the thickness of the internal electrodes to 2 μm or less, and there is a problem in that when the multilayer structure is used, the bulkiness due to the internal electrode thickness is remarkable. This bulking problem,
The same applies when a circuit pattern is provided on a glass epoxy substrate or the like to obtain a multilayer wiring board.

In particular, when a circuit pattern such as an internal electrode is provided on a flexible sheet and the upper and lower layers are overlapped with each other, such as in the case of manufacturing the above-mentioned multilayer ceramic capacitor, the circuit pattern overlapping portion is provided. The unevenness on the surface of the laminate becomes large due to the accumulation of the pattern thickness in the above, and it becomes difficult to laminate a new sheet due to the deformation due to the unevenness difference. In addition, there is a problem that it is difficult to achieve a desired multilayer.

[0005]

The present invention can form a conductive layer such as an internal electrode which is excellent in thinness, can suppress bulkiness based on a conductive layer by multi-layering, and can be applied to a case where circuit patterns and the like overlap in upper and lower layers. Also, the deformation due to the unevenness difference on the surface of the flexible sheet laminate due to its accumulated thickness can be suppressed, and cracks and the like hardly occur even when laminating ceramic green sheets,
In general, it is an object of the present invention to develop a method of manufacturing an electric component capable of realizing a multi-layer structure with a high number of layers, which is difficult with the conventional method.

[0006]

According to the present invention, there is provided a pressure-sensitive adhesive layer having a thickness of at least 1 μm including at least a conductive layer on a pressure-sensitive adhesive layer for reducing an adhesive force by heating.
m, and a conductive layer transfer sheet characterized by having a transfer film of not more than m, and the conductive layer transfer sheet is adhered to an adherend, and the heat treatment is performed to reduce the adhesive force of the adhesive layer. And transferring the transfer film to an adherend, and having a transfer film having a thickness of at most 1 μm including at least a conductive layer formed by the transfer method. It is intended to provide a characteristic electric component.

[0007]

According to the present invention, the conductive layer transfer sheet is adhered to the adherend, heat-treated, the adhesive force of the adhesive layer is reduced, and the conductive layer is removed by a simple operation of peeling the sheet. A transfer layer having a thickness of 1 μm or less can be easily and efficiently transferred to a curved surface of an adherend, and the adhesion reduction process can be efficiently performed with good responsiveness. And the like can be obtained stably with good production efficiency. Further, the transfer film is reinforced by the adhesive layer, and it is possible to safely and efficiently handle an extremely thin film which is difficult to handle alone due to a breakage problem or the like.

As a result, it is possible to form a conductive layer such as an internal electrode which is excellent in thickness, thereby suppressing bulkiness based on the conductive layer due to multi-layering. Deformation due to the unevenness difference on the surface of the laminate can be reduced, and the laminate of a flexible sheet such as a ceramic green sheet can be suppressed from being corrugated, cracking, and the like, and a multi-layer structure with a large number of laminates can be realized.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive layer transfer sheet according to the present invention comprises:
It comprises a transfer film having a thickness of 1 μm or less including at least a conductive layer on an adhesive layer whose adhesive force is reduced by heating. An example is shown in FIG. 1 is a transfer film and 2 is an adhesive layer. In addition, 21 and 22 are a rubber-like organic elastic layer and a base material as needed, respectively.

[0010] The pressure-sensitive adhesive layer which reduces the adhesive force by heating includes, for example, a thermal expansion agent which expands and / or expands by heating and reduces the adhesive area with the adherend by heating so that the adhesive force does not decrease. An appropriate pressure-sensitive adhesive layer such as one that is lost can be used (Japanese Patent Publication Nos. 50-13878, 51-24534, JP-A-56-61468, 56-61469, and 60-252681).
Gazette, JP-A-3-22861, and 5-438
No. 51 publication).

Incidentally, as the above-mentioned thermal expansive agent, an appropriate one such as a foaming agent or heat-expandable microspheres (microcapsules) can be used. Examples of the blowing agent include decomposable inorganic blowing agents such as ammonium carbonate and ammonium hydrogen carbonate, sodium hydrogen carbonate and ammonium nitrite, sodium borohydride and azides, and fluorocarbons such as trichloromonofluoromethane and dichloromonofluoromethane. Alkanes, azobisisobutyronitrile, azodicarbonamide, azo compounds such as barium azodicarboxylate, paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide,
Hydrazine compounds such as 4,4'-oxybis (benzenesulfonylhydrazide) and allylbis (sulfonylhydrazide); semicarbazide compounds such as ρ-toluylenesulfonyl semicarbazide and 4,4'-oxybis (benzenesulfonyl semicarbazide); 5-morpholyl Triazole compounds such as -1,2,3,4-thiatriazole; N-nitroso compounds such as N, N'-dinitrosopentamethylenetetramine and N, N'-dimethyl-N, N'-dinitrosoterephthalamide Organic foaming agents such as compounds.

The heat-expandable microspheres may be made of, for example, an appropriate substance which is easily gasified and exhibits a heat expansion property, such as isobutane, propane or pentane, by an appropriate method such as a coacervation method or an interfacial polymerization method. Forming substances, for example, inside a shell made of a heat-fusible substance such as polyvinylidene chloride-acrylonitrile copolymer or polyvinyl alcohol, polyvinyl butyral or polymethyl methacrylate, polyacrylonitrile or polyvinylidene chloride, polysulfone, or a substance which is destroyed by thermal expansion, etc. Included ones. The average particle size of the heat-expandable microspheres used is generally 100 μm or less, particularly 1 to 50 μm, but is not limited thereto. Note that the heat-expandable microspheres include commercially available products such as microspheres (trade name, manufactured by Matsumoto Yushi-Seiyaku Co., Ltd.).

[0013] From the viewpoint of the responsiveness, operability and controllability of the reduction of the adhesive force due to heating, and especially the stable achievement of the reduction of the adhesive force, heat-expandable microspheres are preferably used. Volume expansion of 5 times or more, especially 7 times or more, especially 1
Those having 0 times or more can be preferably used.

The pressure-sensitive adhesive layer according to the present invention can be formed by adding a thermal expansion agent to the pressure-sensitive adhesive. As the pressure-sensitive adhesive, an appropriate one that allows foaming and / or expansion by heating of the thermal expansion agent can be used. Among them, one that does not restrict thermal expansion of the thermal expansion agent as much as possible is preferably used. sell. Therefore, in the pressure-sensitive adhesive, for example, JP-A-56-61468,
One or two or more of appropriate ones such as those disclosed in JP-A-61-174857, JP-A-63-17981, and JP-A-56-13040 can be used.

Incidentally, specific examples of the pressure-sensitive adhesive include those using polymers such as rubber-based, acrylic-based, vinylalkylether-based, silicone-based, polyester-based, polyamide-based, urethane-based, and styrene-diene block copolymer-based polymers. Or, those having improved creep properties by blending a heat-meltable resin having a melting point of about 200 ° C. or less, if necessary, for example, a crosslinking agent or a tackifier, a plasticizer or a softener, a filler or a pigment, Examples thereof include those containing appropriate additives such as a coloring agent and an antioxidant.

In general, for example, natural rubber, polyisoprene rubber, styrene / butadiene rubber, styrene / isoprene / styrene block copolymer rubber, styrene / butadiene / styrene block copolymer rubber or recycled rubber, butyl rubber, polyisobutylene or NBR A rubber-based pressure-sensitive adhesive using a rubber-based polymer as a base polymer, an acrylic pressure-sensitive adhesive using an acrylic polymer containing an alkyl ester of acrylic acid or methacrylic acid as a base polymer, and the like are used.

Examples of the acrylic polymer include methyl, ethyl, propyl and butyl, amyl and hexyl, heptyl and 2-ethylhexyl, isooctyl and isononyl, isodecyl and dodecyl. Group, lauryl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group,
An ester of acrylic acid or methacrylic acid having a linear or branched alkyl group having 1 to 20, especially 4 to 18 carbon atoms, such as an octadecyl group, a nonadecyl group or an eicosyl group.
And those using two or more species.

The acrylic polymer to be used may be one obtained by copolymerizing one or more kinds of appropriate monomers for the purpose of improving the cohesive force, heat resistance, crosslinkability and the like. There is no particular limitation on the copolymerization monomer,
Any suitable copolymer that can be copolymerized with the acrylic acid-based alkyl ester can be used.

Examples of the copolymerizable monomers include acrylic acid, methacrylic acid, carboxyethyl acrylate and carboxypentyl acrylate, carboxyl group-containing monomers such as itaconic acid and maleic acid, fumaric acid and crotonic acid, maleic anhydride and the like. Acid anhydride monomers such as itaconic anhydride, hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate,
Hydroxybutyl (meth) acrylate and hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate and hydroxydecyl (meth) acrylate,
Examples thereof include hydroxyl group-containing monomers such as hydroxylauryl (meth) acrylate and (4-hydroxymethylcyclohexyl) -methyl methacrylate.

In addition, styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamido-2-methylpropanesulfonic acid, (meth) acrylamidopropanesulfonic acid, sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalenesulfonic acid A sulfonic acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate, a (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide and N-methylol (meth) acrylamide , (N-substituted) amide monomers such as N-methylolpropane (meth) acrylamide, aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, t-butylamido (meth) acrylate Ethyl such as (meth) alkylamino monomers acrylic acid, methoxyethyl (meth) acrylate and (meth) such as acrylic acid ethoxyethyl (meth) acrylic acid alkoxyalkyl based monomers, N
Maleimide monomers such as cyclohexylmaleimide and N-isopropylmaleimide, N-laurylmaleimide and N-phenylmaleimide; N-methylitaconimide and N-ethylitaconimide; N-butylitaconimide and N-octylitaconimide; Itaconimide monomers such as 2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, N- (meth) acryloyloxymethylene succinimide and N- (meth) acryloyl-6-
Succinimide monomers such as oxyhexamethylene succinimide and N- (meth) acryloyl-8-oxyoctamethylene succinimide are also examples of the monomer for copolymerization.

Further, vinyl acetate and vinyl propionate,
N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine and vinylpiperidone, vinylpyrimidine and vinylpiperazine, vinylpyrazine and vinylpyrrole, vinylimidazole and vinyloxazole, vinylmorpholine and N-vinylcarboxylic acid amides, styrene and α-
Vinyl monomers such as methylstyrene and N-vinylcaprolactam, cyanoacrylate monomers such as acrylonitrile and methacrylonitrile, epoxy group-containing acrylic monomers such as glycidyl (meth) acrylate, polyethylene glycol (meth) acrylate and (meth) ) Glycol-based acrylic ester monomers such as polypropylene glycol acrylate, methoxyethylene glycol (meth) acrylate and methoxy polypropylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate and fluorine (meth) acrylate,
Acrylic ester monomers such as silicone (meth) acrylate and 2-methoxyethyl acrylate, hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate and neo Pentyl glycol di (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, epoxy acrylate, polyester acrylate, urethane acrylate And divinylbenzene, polyfunctional monomers such as butyl diacrylate and hexyl diacrylate, isoprene, butadiene, isobutylene and Well as vinyl ether and the like as examples of monomers for copolymerization.

The pressure-sensitive adhesive layer, which is preferable from the viewpoint of a balance between an appropriate adhesive force before heating and a decrease in adhesive force by heating, has a dynamic elastic modulus in a temperature range from room temperature to 150 ° C. of 50,000 to 10
A polymer of 100,000 dyn / cm ² was used as a base polymer.

The amount of the thermal expansion agent may be appropriately determined depending on factors such as the expansion ratio of the pressure-sensitive adhesive layer and the ability to reduce the adhesive strength. Generally, 1 to 100 parts by weight of the base polymer of the adhesive,
150 parts by weight, especially 10 to 130 parts by weight, especially 25 to 1
00 parts by weight of thermal expansion agent is used.

The pressure-sensitive adhesive layer is formed, for example, by blending components such as a thermal expander and a pressure-sensitive adhesive with a solvent, if necessary, and developing the mixture by an appropriate method such as a coating method. Can be performed by a method of forming a The thickness of the adhesive layer can be appropriately determined depending on the surface shape and material of the adherend. In general, from the viewpoint of preventing the adhesive strength from being insufficiently reduced due to insufficient heating deformation due to the excessively small thickness, and preventing the adhesive from remaining and contaminating the adherend due to cohesive failure during peeling after heating due to excessive thickness. , 5-500 μm, especially 10
４００400 μm, especially 20-300 μm.

In forming the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer 2 may be supported by a base material 22 as necessary as shown in FIG. Such a support form has an advantage that the transferability of the transfer sheet is improved by supporting and reinforcing the adhesive layer and eventually the transfer film with the base material, and the transfer film can be safely and efficiently transferred without being damaged. are doing. Further, even if an extremely thin film such as a gold foil can be supplied, it is difficult to handle in a large area due to easy breakage and the like, and a material having poor workability such as a sticking operation is adhered to the adhesive layer of the supporting form, and the transfer sheet according to the present invention. By treating as, there is also an advantage that the construction in a large area becomes easy and the sticking work and the like can be performed efficiently.

As the substrate, for example, an adhesive layer such as paper, cloth or nonwoven fabric, porous material such as porous film or net, plastic film or rubber sheet, foamed sheet or metal foil, or a laminate thereof is supported. A suitable thin leaf body or the like can be used. In particular, a base material that does not melt at the heat treatment temperature of the pressure-sensitive adhesive layer is preferable from the viewpoint of handling properties after heating. The substrate may be one in which deformability such as elongation is controlled by a stretching treatment or the like. The thickness of the substrate can be appropriately determined depending on the strength, flexibility, and the like, and is generally 500 μm or less, particularly 1 to 300 μm, and particularly 5 to 250 μm, but is not limited thereto.

The formation of the sheet in a form in which the adhesive layer is supported by the substrate may be performed, for example, by performing the above-described spreading operation on the substrate and directly attaching the adhesive layer on the substrate, or by applying the adhesive layer on the separator according to the method. And an appropriate method such as a method of transferring the adhesive layer to a substrate. The separator is, for example, one obtained by subjecting the base material to a surface treatment with an appropriate release agent such as a silicone-based or long-chain alkyl-based, fluorine-based or molybdenum sulfide, polytetrafluoroethylene, polychlorotrifluoroethylene, or polyvinyl fluoride. Polyvinylidene fluoride, tetrafluoroethylene / hexafluoropropylene copolymer and chlorotrifluoroethylene /
It can be obtained as a low-adhesion base made of a fluoropolymer such as a vinylidene fluoride copolymer, a low-adhesion base made of a nonpolar polymer such as polyethylene or polypropylene, and the like. Note that a separator can also be used as a substrate for supporting the above-mentioned adhesive layer.

In the above, the pressure-sensitive adhesive layer can be provided on one or both sides of the base material, and the base material may be embedded in the pressure-sensitive adhesive layer. The base material having excellent adhesion to the adhesive layer is, for example, a method using a film made of a high-polar polymer such as polyester, a chemical or physical method such as a chromic acid treatment, an ozone exposure, a flame exposure, a high piezoelectric shock exposure, and an ionizing radiation treatment. It can be obtained by a method of performing an appropriate treatment such as a surface oxidation treatment by a typical method.

In order to improve the adhesion between the substrate and the adhesive layer,
A method of providing an undercoat layer on a base material is also effective. In the case where the adhesive layer is supported by the substrate as described above, one or more intermediate layers may be provided between the substrate and the adhesive layer. The intermediate layer may have an appropriate purpose, such as the above-mentioned coating layer of a release agent for imparting releasability, and conversely, the undercoat layer for improving adhesion.

Incidentally, examples of the intermediate layer other than the release coat layer and the undercoat layer include a layer for imparting good deformability, a layer for increasing the adhesion area to an adherend,
A layer intended to improve the adhesive force, a layer intended to appropriately follow the surface shape of the adherend, a layer intended to improve the processability of reducing the adhesive force by heating, and an adherend after heating And a layer for the purpose of further improving the releasability.

From the viewpoint of imparting deformability and improving peelability after heating, it is effective to provide the rubbery organic elastic layer 21 as an intermediate layer as illustrated in FIG.
Such a rubber-like organic elastic layer functions to provide a large bonding area by its surface following the surface shape of the adherend when the transfer sheet is adhered to the adherend, and to expand the adhesive layer during heating. It functions to enhance controllability, expands the adhesive layer more favorably in the thickness direction than in the plane direction by heating, and functions to form an expanded layer having excellent thickness uniformity.

The rubbery organic elastic layer, which is preferable from the viewpoint of the above-mentioned workability, is preferably a natural rubber or a synthetic rubber having a hardness of 50 or less, especially 45 or less, particularly 40 or less based on the D-type hardness of D-type Shore of ASTM D-2240. It is formed of rubber or a synthetic resin having rubber elasticity. The thickness is usually 500 μm or less from the viewpoint of the above-mentioned functions, and especially 3 to 3
The thickness is set to 00 μm, particularly 5 to 150 μm, but is not limited thereto.

Examples of the synthetic rubber or synthetic resin include synthetic rubbers such as nitrile, diene, and acrylic resins, thermoplastic elastomers such as polyolefin and polyester, ethylene-vinyl acetate copolymer, polyurethane, polybutadiene, and the like. A synthetic resin having rubber elasticity, such as soft polyvinyl chloride, may be used. In the present invention, an essentially hard polymer such as polyvinyl chloride having rubber elasticity in combination with a compounding agent such as a plasticizer or a softener can also be used. Adhesive substances such as the above-mentioned adhesives and base polymers thereof can also be preferably used for forming the rubbery organic elastic layer.

The rubber-like organic elastic layer is formed by an appropriate method such as a method of applying a solution of the forming material on a base material or a method of bonding a film or the like made of the forming material to the base material. Can be. The rubbery organic elastic layer may be formed as an adhesive substance containing the above-mentioned forming material as a main component, or may be formed as a foamed film or the like mainly containing such a component.

The transfer film can be provided by an appropriate method such as a method of directly providing the transfer film on the pressure-sensitive adhesive layer or a method of transferring a film provided on the base material onto the pressure-sensitive adhesive layer. As the base material, a material having a weak adhesive force to the transfer film, such as those exemplified above for the separator, can be preferably used.

The transfer film formed of a thin film having a thickness of 1 μm or less including at least a conductive layer is formed by, for example, a vacuum deposition method such as a resistance heating method, an arc discharge heating method, an electron beam heating method, a high frequency discharge method, or a magnetron method. It can be performed by a suitable thin film forming method such as a sputtering method, an ion plating method, a substitution method, a chemical reduction method, an electroless plating method such as a disproportionation reaction method, and other plating methods. Further, a metal foil or another film which can be obtained as a thin film having a thickness of 1 μm or less, such as a gold foil, can also be used for forming the transfer film.

The transfer film is formed so as to include at least a conductive layer, and is therefore formed as a single layer or a two or more superposed layer having a total thickness of 1 μm or less. The preferable total thickness of the transfer film is 0.9 μm or less, especially 50 ° to 0.8 μm from the viewpoint of thin film properties, transferability, and damage prevention during transfer.
m, especially 100 ° to 0.7 μm. Therefore, in the case of a transfer film comprising two or more superposed layers, each layer forming the transfer film may have a smaller thickness.

The conductive layer forming the transfer film is not particularly limited, and can be formed of an appropriate material having conductivity. Generally, for example, gold and copper, platinum and nickel,
Silver and tin, indium and bismuth, lead and zinc, aluminum and palladium, chromium and iron, manganese and magnesium, tin oxide and indium oxide, silicon and gallium,
Various metals and semiconductors, such as gallium arsenide and gallium phosphide,
An alloy thereof is used. Also, a superconducting material or the like can be used.

The transfer film comprises two or more conductive layers such as a superimposed layer of different metals or a sandwich structure for the purpose of improving transferability, conductivity, transferability to an adherend, and transfer adhesion. It may be formed as an appropriate multilayer structure having two or three or more layers. Incidentally, a metal barrier layer made of nickel or the like can be superposed for the purpose of preventing electrical contact failure due to migration. Further, a soft metal layer can be superimposed for the purpose of improving the transfer adhesion to the adherend.

The transfer film may include a layer other than the conductive layer. Such a layer is incorporated in the transfer film in advance for the purpose of eliminating the necessity of being provided on the adherend in a separate step from the transfer according to the present invention and reducing the thickness of the formed film. Accordingly, the type of the layer can be appropriately determined according to the purpose of use of the transfer sheet, such as an insulating layer and a layer for controlling capacitance. By the way, examples thereof include a layer made of barium titanate-based or strontium titanate-based ceramic, silica and alumina, titania and zinc oxide, tantalum oxide and tungsten oxide, zinc sulfide and zinc selenide,
A layer made of a metal oxide or a metal compound such as cadmium oxide; The number of layers other than the conductive layer to be incorporated is
Any number of one or more layers can be used, and the arrangement position can be appropriately determined according to the purpose of assembly.

The transfer film provided on the adhesive layer may be a continuous film, or may be a film formed in an appropriate form for the purpose of forming a circuit pattern such as an internal electrode. The patterning is performed, for example, by a method of forming a patterned transfer film via a pattern mask when forming the above-described transfer film, a transfer film consisting of a continuous film provided on an adhesive layer or a substrate, and a photolithography method. It can be performed by an appropriate method such as a method of performing an etching process by the method described above.

When a transfer film is formed by an electroless plating method, a patterned transfer film may be formed by patterning the adhesive layer or the base material by a photolithography method and then plating. it can. If it is difficult to pattern the transfer film provided on the adhesive layer, for example, the adhesion of the adhesive layer or the heat expansion property is impaired due to the involvement of a vacuum atmosphere or a strong basic etching solution, etc. A method in which the transfer film provided thereon is patterned and transferred onto the adhesive layer can be preferably applied.

The conductive layer transfer sheet according to the present invention is bonded to an adherend and subjected to a heat treatment, and the adhesive layer is foamed and / or expanded to reduce its adhesive force. By peeling from the body, the transfer film can be separated from the pressure-sensitive adhesive layer having reduced or lost adhesive force and transferred to the adherend. Therefore, by transferring the transfer film to the adherend by the transfer method using the conductive layer transfer sheet, an electric component having a conductive layer such as a circuit pattern having excellent thinness can be easily and efficiently formed. be able to.

In the above heat treatment, it is preferable that the transfer sheet is adhered to the adherend via the adhesive layer from the viewpoint of good transferability without damaging the transfer film. Therefore, when bonding to the adherend, it is preferable that a part of the adhesive layer on the lower surface of the transfer film is exposed. However, exposure of a part of the above-mentioned adhesive layer is not indispensable because heat transfer can be performed under pressure through a weight or the like to achieve good transfer of the transfer film. The adhesive layer provided with the transfer film may be temporarily attached with a separator or the like for protection of the transfer film or the exposed adhesive surface, and stored.

The heat treatment of the pressure-sensitive adhesive layer in the conductive layer transfer sheet can be performed through an appropriate heating means such as a hot plate, a hot-air dryer, or a near-infrared lamp.
The conditions of the heat treatment are appropriately determined in accordance with the conditions such as the surface state of the adherend, the decrease in the adhesive area due to the type of the thermal expansion agent, the heat resistance of the substrate and the adherend, the heat capacity, the heating means, and the like. Can be. Generally at a temperature of 100-250 ° C,
Heat treatment for 90 seconds (hot plate or the like) or 5 to 15 minutes (hot air dryer or the like) is not limited to this.

The heat treatment expands and / or foams the thermal expansion agent and expands and deforms the pressure-sensitive adhesive layer to reduce or lose the adhesive force. Even when the adherend has no adhesive force, the transfer film is not damaged. It is transferred and held on the adherend by the adhesion force based on the thin film activity or the like. The adherend to which the transfer film is to be transferred is not particularly limited, and may be made of any material such as metal, ceramic, plastic, wood, and paper. It may have an arbitrary shape such as fiber or fiber shape.

Although the conductive layer transfer sheet according to the present invention can be used as a plating material or a decorative material, the conductive layer having excellent thickness can be easily formed as a high-accuracy transfer pattern. Formation, leads of electronic components such as semiconductor lasers and ICs, electrical joints between the leads and electric circuit boards, electrical joints between printed wiring boards and flat cables, inside and outside of chip-shaped electronic components For the manufacture of electrical components by forming electrical joints such as electrodes, especially for the manufacture of multilayer ceramic capacitors by forming internal electrodes utilizing thin film properties, and for the manufacture of multilayer wiring boards using glass epoxy substrates, etc. It can be preferably used.

Incidentally, the production of the above-mentioned multilayer ceramic capacitor is carried out, for example, by using a conductive layer transfer sheet according to the present invention having a patterned transfer film as an internal electrode.
While repeating the operation of transferring the transfer film onto the ceramic green sheet by the above-described transfer method, the obtained green sheets can be sequentially laminated and multilayered.

In the above, in the present invention, an adherend such as a ceramic green sheet or the like is adhered to both sides of the transfer sheet using a transfer sheet having an adhesive layer or the like on both sides of the substrate. The method of transferring the transfer film on the adhesive layer to each of the adherends arranged on both sides of the transfer sheet by applying the method described above can also be adopted. According to this method, the transfer film can be transferred to the two adherend surfaces by a single heat treatment, and is excellent in processing efficiency and the like.

[0050]

EXAMPLE 1 A solution of an acrylic copolymer A consisting of 100 parts of butyl acrylate (with weight, the same applies hereinafter), 5 parts of ethyl acrylate and 3 parts of acrylic acid was applied to one side of a PET film having a thickness of 100 μm. It is applied and dried to form a rubbery organic elastic layer having a thickness of 10 μm, and the acrylic copolymer A10 is formed thereon.
0 parts and heat-expandable microspheres (Microsphere F-50
D) Thickness 3 consisting of 30 parts and 2 parts of a polyurethane crosslinking agent
An adhesive sheet was obtained by providing an acrylic adhesive layer having a thickness of 5 μm. The acrylic pressure-sensitive adhesive layer was provided by transferring what was formed on the separator.

On the other hand, a polytetrafluoroethylene film having a thickness of 50 μm was coated on one side with a thickness of 0.5 by a vacuum evaporation method.
After forming a μm nickel thin film, it was etched to form a predetermined electrode pattern, which was adhered to the pressure-sensitive adhesive sheet to obtain a conductive layer transfer sheet. In that case, the electrode pattern on the film was adhered to the adhesive surface and the film was peeled off, whereby the electrode pattern was easily transferred to the adhesive surface without damage.

Next, the conductive layer transfer sheet was adhered to a green sheet made of barium titanate and having a thickness of 10 μm, and heat-treated at 130 ° C. for 10 minutes in a hot air drier to lose the adhesive strength of the adhesive layer. The transfer sheet was peeled off to obtain a green sheet to which the nickel electrode pattern was successfully transferred without damage, and the operation of sequentially laminating the obtained sheets was repeated to obtain a laminate having 100 laminations. When the cross section of this laminate was observed with an electron microscope, the thickness of the green sheet layer was 10 to 11 μm, and the thickness of the internal electrode layer was 0.5
μm. In the laminating operation, the electrode pattern did not fall off the green sheet at all.

Example 2 An electroless plating method using a plating bath composition (pH 5) of 30 g / l of nickel sulfate, 30 g / l of boric acid, 3 g / l of ammonium chloride, 20 g / l of sodium hypophosphite, and 5 g / l of ammonium acetate (Bath temperature: 80 ° C.), except that a nickel electrode pattern was formed on a ceramic green sheet previously patterned by a photolithography method, and a conductive layer transfer sheet was obtained in accordance with Example 1. A laminate of 100 green sheets was obtained. Observation of the cross section of this laminate with an electron microscope showed that the thickness of the green sheet layer was 10 to 11 μm and the thickness of the internal electrode layer was 0.5 μm. In addition, in the laminating operation,
The electrode pattern did not fall off the green sheet at all.

Comparative Example A nickel paste was screen-printed on a green sheet to form an electrode pattern, and the operation of stacking the electrode pattern was sequentially repeated to obtain a laminate. Observation of the cross section of this laminate with an electron microscope showed that the thickness of the green sheet layer was 10 to 1
Although the thickness was 1 μm, the thickness of the internal electrode layer was 3 μm.
Therefore, when about 50 layers were stacked, the unevenness of the surface of the stacked body became large, and when a green sheet was stacked thereon, cracks were generated, and a stacked body having 100 stacked layers could not be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a conductive layer transfer sheet.

[Description of sign]

 1: transfer film including conductive layer 2: adhesive layer 21: rubber-like organic elastic layer 22: base material

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[Procedure amendment]

[Submission date] November 2, 1999 (1999.11.
2)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction contents]

[0006]

According to the present invention, there is provided a method for foaming or expanding by heating.
A conductive layer transfer sheet, comprising a transfer film having a thickness of 1 μm or less including at least a conductive layer, on a pressure-sensitive adhesive layer containing a thermal expansion agent to be stretched and reducing the adhesive force by heating; The method is characterized in that the layer transfer sheet is adhered to the adherend, the heat transfer treatment is performed to reduce the adhesive force of the adhesive layer, the transfer sheet is peeled off, and the transfer film is transferred to the adherend. The present invention provides an electric component characterized by having a transfer method and a transfer film formed by the transfer method and including a conductive layer and having a thickness of 1 μm or less.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

[0007]

According to the present invention, the conductive layer transfer sheet is adhered to the adherend and heat-treated to expand the thermal expansion agent and / or
By a simple operation of peeling off the sheet by reducing the adhesive force due to expansion deformation of the adhesive layer due to foaming, a transfer film having a thickness of 1 μm or less including a conductive layer can be easily and efficiently applied to a curved surface of an adherend. The transfer can be performed, and the treatment for reducing the adhesive force can be efficiently performed with good responsiveness. Thus, it is possible to stably obtain an electric component having a thin conductive layer or the like with good production efficiency. Further, the transfer film is reinforced by the adhesive layer, and it is possible to safely and efficiently handle an extremely thin film which is difficult to handle alone due to a breakage problem or the like.

[Procedure amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The conductive layer transfer sheet according to the present invention comprises:
A transfer film having a thickness of 1 μm or less including at least a conductive layer is provided on a pressure-sensitive adhesive layer containing a thermal expansion agent that expands or expands by heating and reduces the adhesive force by heating. An example is shown in FIG. 1 is a transfer film and 2 is an adhesive layer. In addition, 21 and 22 are a rubber-like organic elastic layer and a base material as needed, respectively.

[Procedure amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0010

[Correction method] Change

[Correction contents]

[0010] As the adhesive layer to reduce the adhesive force by heating, the heating contains a thermal expansion agent for foaming and / or expansion by applying heat, adhesion by, for example, to reduce the adhesion area of an adherend An appropriate pressure-sensitive adhesive layer such as a layer which is reduced or lost can be used (Japanese Patent Publication Nos. 50-13878 and 51-24534, and JP-A-56-6146).
No. 8, No. 56-61469, No. 60-252
681, JP-A-3-22861, and 5-
No. 43851).

Continued on the front page (72) Inventor Yukio Arimitsu 1-1-2 Shimohozumi, Ibaraki-shi, Osaka Nitto Denko Corporation (72) Inventor Kazuyuki Kiuchi 1-2-1, Shimohozumi, Ibaraki-shi, Osaka Nitto F-term (reference) in Electric Works Co., Ltd. 4J004 AA04 AA05 AA06 AA08 AA10 AA11 AA14 AA15 AA16 AA17 AA18 CA01 CA03 CA04 CA05 CA06 CA08 CB01 CB02 CB04 CC03 CC07 CE02 FA05 4J040 JA09 JB09 KA03 KA37 LA04 MA20 PA03 MA04 BB23 BB24 BB25 BB34 BB44 BB49 DD23 DD25 DD33 DD56 DD76 ER52

Claims (8)

[Claims] 1. A conductive layer transfer sheet comprising a transfer film having a thickness of 1 μm or less including at least a conductive layer on an adhesive layer whose adhesive force is reduced by heating. 2. The conductive layer transfer sheet according to claim 1, wherein the adhesive layer contains heat-expandable microspheres and is supported by a substrate. 3. The conductive layer transfer sheet according to claim 1, wherein the pressure-sensitive adhesive layer is supported on the substrate via a rubber-like organic elastic layer. 4. The conductive layer transfer sheet according to claim 1, wherein the transfer film is a vacuum deposited film, a sputtering film, or an electroless plated film. 5. The conductive layer transfer sheet according to claim 1, wherein the transfer film is patterned. 6. The conductive layer transfer sheet according to claim 5, wherein the transfer film is patterned by etching. 7. The conductive layer transfer sheet according to claim 1 is adhered to an adherend, the heat treatment is performed to reduce the adhesive force of the adhesive layer, and then the transfer sheet is peeled off. A transfer method comprising transferring a transfer film to an adherend. 8. An electric component comprising a transfer film formed by the transfer method according to claim 7 and including a conductive layer and having a thickness of 1 μm or less.