JP2003243805A - Circuit forming transfer material and method of manufacturing circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit forming transfer material which is capable of transferring a circuit pattern easily and stably on an insulating board or a ceramic green sheet kept in a semi-cured state even if the circuit pattern is reduced in line width so as to form a high-accuracy circuit board and a method of manufacturing a circuit board. <P>SOLUTION: A circuit forming transfer material is used for transferring the circuit pattern onto the insulating board or the ceramic green sheet kept in a semi-cured condition. The transfer material is equipped with a base material, an adhesive layer which is formed on the base material, contains a gas producing agent that produces a gas when it is stimulated, and reduces its adhesive power when it is stimulated, and the circuit pattern formed on the adhesive layer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer material for forming a circuit and a transfer material for forming the circuit, which makes it possible to easily and stably transfer a circuit pattern to an insulating substrate or a ceramic green sheet in a semi-cured state. The present invention relates to a method for manufacturing a circuit board using a material.

[0002]

2. Description of the Related Art A circuit board having a circuit pattern formed on an insulating board is used in various devices such as electronic devices and automobiles. Among them, circuit boards using an insulating substrate made of synthetic resin are widely used because they are less likely to be cracked or chipped and can be easily multilayered by hot pressing.

As a method of forming a circuit pattern on an insulating substrate made of synthetic resin, various methods of patterning a metal foil have been proposed in order to improve the flatness of the obtained circuit pattern and the reliability of electrical connection. ing. For example, in Japanese Patent Laid-Open No. 10-51108, a metal foil is bonded onto a resin film, a circuit pattern is formed by etching the metal foil, and then the circuit pattern is transferred to an insulating substrate made of synthetic resin. A method of doing so is disclosed. By using this transfer method, the insulating substrate does not come into contact with the etching liquid or the like when forming the circuit pattern, so that the characteristics of the insulating substrate are not deteriorated,
A circuit board can be obtained.

However, in this type of transfer method, when the circuit pattern is transferred to the insulating substrate, the transfer is performed by hot pressing at a relatively high temperature of about 120 ° C., so that the insulating substrate and the circuit pattern are transferred. There is a problem that the thermal stress and strain remain and the accuracy of the obtained circuit board decreases.

Particularly, when a plurality of insulating substrates having transferred circuit patterns are hot-pressed to form a multilayer substrate after the circuit patterns are transferred to the insulating substrate, each insulating substrate and circuit pattern In addition, since the thermal stress and strain at the time of transfer are different from each other, a plurality of circuit patterns may not accurately overlap each other on the multilayer substrate, or the accuracy of the circuit patterns tends to deteriorate.

In addition, in recent years, with the increasing density of electronic equipment, the width of circuit patterns has become narrower, and has become thinner than 50 μm. When the line width of the circuit pattern becomes thin in this way, it becomes difficult to perform transfer by the transfer method. Also,
When patterning the metal foil by etching, the width of the wiring part on the substrate and the width of the upper wiring part in contact with the resist increases as the width of the wiring forming the circuit pattern undergoes side etching and the line width becomes narrower. And the transfer becomes more difficult.

On the other hand, a circuit board having a circuit pattern formed on a ceramic substrate has been widely used.
In this type of ceramic substrate, a circuit pattern is formed on the ceramic substrate obtained by firing a ceramic green sheet by a thin film forming method or the like. When manufacturing a laminated ceramic substrate or the like, first, a circuit pattern is formed on the ceramic green sheet by printing a conductive paste or the like, and then a plurality of ceramic green sheets are laminated and the laminated body is fired to form a laminated ceramic. A substrate is obtained.

As described above, when a circuit pattern is formed on the ceramic green sheet, it is difficult to form a complicated circuit pattern with high accuracy because the ceramic green sheet is in an unfired state and is not cured. there were.

Therefore, on the ceramic green sheet,
It is considered that a highly accurate circuit pattern can be formed by forming a circuit pattern by a transfer method, and a transfer material for circuit formation satisfying such a demand has been demanded.

[0010]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide an insulating substrate in which the circuit pattern is semi-cured easily and stably even when the width of the circuit pattern is reduced. Another object of the present invention is to provide a transfer material for forming a circuit and a method for manufacturing a circuit board, which can be transferred to a ceramic green sheet and can obtain a highly accurate circuit board.

[0011]

The present invention 1 is a transfer material for forming a circuit, which is used for transferring a circuit pattern to an insulating substrate in a semi-cured state or a ceramic green sheet, which comprises a base material. An adhesive layer which is provided on the base material, contains a gas generating agent that generates a gas by stimulation, and has an adhesive strength reduced by stimulation, and a circuit pattern formed on the adhesive layer. This is a circuit-forming transfer material.

A second aspect of the present invention is a method of manufacturing a circuit board using the circuit-forming transfer material of the first aspect of the present invention, which comprises a step of preparing the circuit-forming transfer material and a circuit pattern of the circuit-forming transfer material. A step of heat-pressing an insulating substrate in a semi-cured state, or a ceramic green sheet, and stimulating an adhesive layer on the circuit-forming transfer material before or after the heat-pressing to a metal foil. A step of lowering the adhesive force than before giving a stimulus, and after reducing the adhesive force of the adhesive layer, the circuit pattern is peeled from the adhesive layer, and the circuit pattern is the insulating substrate or And a step of transferring to a ceramic green sheet.

In a particular aspect of the method for manufacturing a circuit board according to the second aspect of the present invention, a thermosetting resin in a semi-cured state is used as a material for the insulating substrate in the semi-cured state.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION A method for manufacturing a transfer material for circuit formation and a circuit board according to the present invention will be clarified by describing specific embodiments of the present invention.

With reference to FIG. 1, the structure of a transfer material for circuit formation according to an embodiment of the present invention will be described. As shown in FIG. 1, the transfer material 1 for forming a circuit of the present embodiment includes a base material 2,
The adhesive layer 3 provided on the base material 2 and the circuit pattern 4 formed on the adhesive layer 3 are provided.

As the base material 2, a material made of an appropriate material that supports the adhesive layer 3 and can firmly adhere to the adhesive layer 3 even when the adhesive layer 3 loses its adhesive force due to light irradiation is used. However, when the stimulus for reducing the adhesive force of the adhesive or the stimulus for generating a gas from the gas generating agent is the stimulus by light, it is preferable that the light can be transmitted or passed. Although various synthetic resins and the like can be cited as materials for forming such a base material, polyethylene terephthalate is used in the present embodiment. Further, the surface of the base material 2 may be subjected to a treatment such as a corona treatment or a urethane treatment for the purpose of increasing the adhesive force.

The adhesive layer 3 is composed of an adhesive whose adhesive strength is reduced by stimulation and a gas generating agent which generates gas by stimulation. In the present specification, the adhesive also includes an adhesive. The stimulus is not particularly limited, and examples thereof include stimulus by light, heat, ultrasonic waves, and impact. The stimulus for reducing the adhesive force of the adhesive and the stimulus for generating gas from the gas generating agent may be different. As an adhesive agent whose adhesive force is reduced by heat stimulation or a gas generating agent which generates gas by heat stimulation, the temperature at which adhesive force is lowered or gas is generated is such that thermal stress or heat stress is applied to the multilayer substrate or circuit pattern. It is preferable to use a material that does not give strain.

Examples of the adhesive whose adhesive strength is reduced by the above-mentioned stimulus include, for example, alkyl acrylate-based and / or methacrylic acid alkyl ester-based polymerizable polymers having a radical-polymerizable unsaturated bond in the molecule. When,
A photocurable adhesive containing a radically polymerizable polyfunctional oligomer or monomer as a main component and optionally a photopolymerization initiator, or an acrylic having a radically polymerizable unsaturated bond in the molecule. A thermosetting adhesive or the like containing a heat-polymerization initiator as a main component of a polymerizable polymer of acid alkyl ester and / or methacrylic acid alkyl ester and a radically polymerizable polyfunctional oligomer or monomer Is mentioned.

In such post-curing type adhesives such as photo-curing type adhesives or thermosetting type adhesives, the entire adhesive layer is uniformly and rapidly polymerized and crosslinked by light irradiation or heating to be integrated. Therefore, the increase in elastic modulus due to polymerization hardening becomes significant,
The adhesive strength is greatly reduced.

For the above-mentioned polymerizable polymer, for example, a (meth) acrylic polymer having a functional group in the molecule (hereinafter referred to as a functional group-containing (meth) acrylic polymer) is synthesized in advance, and the above-mentioned functional group is incorporated into the molecule. A compound having a functional group that reacts with a group and a radically polymerizable unsaturated bond (hereinafter,
It can be obtained by reacting with a functional group-containing unsaturated compound).

The above-mentioned functional group-containing (meth) acrylic polymer is a polymer having tackiness at room temperature, and like the general (meth) acrylic polymer, the carbon number of the alkyl group is usually in the range of 2-18. Of the acrylic acid alkyl ester and / or the methacrylic acid alkyl ester as a main monomer, and a functional group-containing monomer and, if necessary, another modifying monomer which can be copolymerized therewith by a conventional method. It is obtained by The weight average molecular weight of the functional group-containing (meth) acrylic polymer is usually about 200 to 2,000,000.

Examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid and methacrylic acid; hydroxyl group-containing monomers such as hydroxyethyl acrylate and hydroxyethyl methacrylate; glycidyl acrylate and glycidyl methacrylate. Epoxy group-containing monomers; isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate; amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.

Examples of the other copolymerizable modifying monomer include various monomers used for general (meth) acrylic polymers such as vinyl acetate, acrylonitrile and styrene.

The functional group-containing unsaturated compound to be reacted with the functional group-containing (meth) acrylic polymer is the same as the functional group-containing monomer described above depending on the functional group of the functional group-containing (meth) acrylic polymer. You can use one. For example, when the functional group of the functional group-containing (meth) acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used, and when the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used, and when the functional group is an amino group, an epoxy group-containing monomer is used.

The polyfunctional oligomer or monomer preferably has a molecular weight of 10,000 or less, and more preferably has a molecular weight so that the adhesive layer can be efficiently three-dimensionally reticulated by heating or light irradiation. 5,000 or less and the number of radically polymerizable unsaturated bonds in the molecule is 2 to
There are six. Such more preferable polyfunctional oligomers or monomers include, for example, trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate. Alternatively, methacrylates similar to the above may be used. Other,
1,4-butylene glycol diacrylate, 1,6-
Examples thereof include hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and methacrylates similar to the above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

The photopolymerization initiator is, for example, 25
Examples thereof include those activated by irradiation with light having a wavelength of 0 to 800 nm. Examples of such photopolymerization initiators include acetophenone derivative compounds such as methoxyacetophenone; benzoinpropyl ether, benzoin isobutyl ether, and the like. Benzoin ether compounds; ketal derivative compounds such as benzyl dimethyl ketal and acetophenone diethyl ketal; phosphine oxide derivative compounds; bis (η5-cyclopentadienyl) titanocene derivative compounds, benzophenone, Michler's ketone, chlorothioxanthone, todecylthioxanthone, dimethylthioxanthone , Diethylthioxanthone, α-hydroxycyclohexyl phenyl ketone, 2
Examples thereof include a radical photopolymerization initiator such as hydroxymethylphenylpropane. These photopolymerization initiators may be used alone or in combination of two or more.

Examples of the above-mentioned thermal polymerization initiator include those which are decomposed by heat to generate active radicals which initiate polymerization and curing, and specific examples thereof include dicumyl peroxide and di-t-butyl peroxide. t-butyl peroxybenzole, t-butyl hydroperoxide, benzoyl peroxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide, di-t-
Butyl peroxide and the like can be mentioned. Among them, cumene hydroperoxide, paramenthane hydroperoxide, di-t-butyl peroxide and the like are preferable because of their high thermal decomposition temperature. Of these thermal polymerization initiators, commercially available ones are not particularly limited, but for example, perbutyl D, perbutyl H, perbutyl P, permenta H (all of which are manufactured by NOF Corporation) and the like are preferable. These thermal polymerization initiators may be used alone or in combination of two or more.

As the adhesive whose adhesive strength is reduced by the above-mentioned stimulus, it is preferable to select and use one having thermoplasticity from the above-mentioned post-curable adhesives. By using a material having thermoplasticity, it is possible to satisfactorily follow and adhere even to an adherend having unevenness on the surface when pressed against the adherend while applying heat by a hot press, a thermal laminating or the like. .

In addition to the above components, the above-mentioned post-curable adhesive is optionally blended with a general adhesive such as an isocyanate compound, a melamine compound or an epoxy compound for the purpose of adjusting the cohesive force of the adhesive. You may mix | blend various various polyfunctional compounds. Further, known additives such as a plasticizer, a resin, a surfactant, a wax and a fine particle filler can be added.

The adhesive layer 3 contains, in addition to the adhesive whose adhesive strength is reduced by the stimulus, a gas generating agent which generates a gas by the stimulus. By stimulating the adhesive layer 3, gas is generated from the gas generating agent in the adhesive layer 3, the adhesive force is further reduced, and the adherend can be peeled off more easily.

The gas generating agent for generating a gas by the above stimulation is not particularly limited, but for example, an azo compound and an azide compound are preferably used. Examples of the azo compound include 2,2′-azobis- (N-butyl-2-
Methylpropionamide), 2,2'-azobis {2-
Methyl-N- [1,1-bis (hydroxymethyl) -2
-Hydroxyethyl] propionamide}, 2,2'-
Azobis {2-methyl-N- [2- (1-hydroxybutyl)] propionamide}, 2,2'-azobis [2
-Methyl-N- (2-hydroxyethyl) propionamide], 2,2'-azobis [N- (2-propenyl)
2-Methylpropionamide], 2,2′-azobis (N-butyl-2-methylpropionamide), 2,
2'-azobis (N-cyclohexyl-2-methylpropionamide), 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (2-Imidazoylin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolinyl-
2-yl) propane] disulfate dihydrolate, 2,2'-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'- Azobis {2- [1- (2-
Hydroxyethyl) -2-imidazolidin-2-yl]
Propane} dihydrochloride, 2,2′-azobis [2- (2-imidazolinyl-2-yl) propane],
2,2'-azobis (2-methylpropionamidine) hydrochloride, 2,2'-azobis (2-aminopropane) dihydrochloride, 2,2'-azobis [N- (2-carboxyacyl) -2 -Methyl-propionamidine], 2,2'-azobis {2- [N
-(2-carboxyethyl) amidine] propane},
2,2'-azobis (2-methylpropionamide oxime), dimethyl 2,2'-azobis (2-methylpropionate), dimethyl 2,2'-azobisisobutyrate, 4,4'-azobis ( 4-Cyancarbonic acid), 4,4′-azobis (4-cyanopentanoic acid), 2,2′-azobis (2,4,4-trimethylpentane) and the like. Above all 2,2 '
-Azobis- (N-butyl-2-methylpropionamide), 2,2'-azobis (N-butyl-2-methylpropionamide), 2,2'-azobis (N-cyclohexyl-2-methylpropionamide) Is preferred.
These azo compounds generate nitrogen gas when stimulated by light, heat or the like.

Examples of the azide compound include 3-
Examples thereof include azidomethyl-3-methyloxetane, terephthalazide, p-tert-butylbenzazide; polymers having an azide group such as glycidyl azide polymer obtained by ring-opening polymerization of 3-azidomethyl-3-methyloxetane. These azide compounds generate nitrogen gas when stimulated by light, heat and impact.

Among these gas generating agents, the azide compound is easily decomposed by releasing impact to release nitrogen gas, so that it is difficult to handle. Furthermore, since the azide compound causes a chain reaction once the decomposition starts and explosively releases nitrogen gas and cannot control it, the adherend may be damaged by the explosively generated nitrogen gas. There are also problems. Due to such a problem, the amount of the azide compound used is limited, but a sufficient effect may not be obtained with the limited amount used. On the other hand, unlike the azide compound, the azo compound does not generate a gas upon impact, and is therefore extremely easy to handle. Also, since it does not cause a chain reaction to explosively generate gas, it does not damage the adherend, and gas generation can be stopped by interrupting light irradiation. It also has the advantage of being controllable. Therefore, it is more preferable to use an azo compound as the gas generating agent.

The gas generating agent may be dispersed in the adhesive layer 3, but if the gas generating agent is dispersed in the adhesive layer 3, the entire adhesive layer 3 becomes a foam and becomes soft. Therefore, the adhesive force reducing mechanism of the post-curable adhesive, which hardens the adhesive layer by applying stimulus to reduce the adhesive force, may not work well. Therefore, it is preferable that the gas generating agent is contained only in the surface layer portion of the adhesive layer 3 that is in contact with the metal foil 4. If it is contained only in the surface layer portion, the adhesive layer can be sufficiently hardened by light irradiation, and at the surface layer portion of the adhesive layer in contact with the circuit pattern 4, gas is generated from the gas generating agent and the circuit pattern 4 is formed. Then, a part of the adhesive surface of the adhesive substance is peeled off to reduce the adhesive strength.

As a method of containing the gas generating agent only in the surface layer portion of the adhesive layer 3, for example, the gas generating agent is contained in a thickness of about a primer on a layer made of the above adhesive prepared in advance. Examples thereof include a method of applying the above-mentioned adhesive, a method of applying a volatile liquid containing a gas generating agent or a method of uniformly spraying the gas generating agent on the surface by spraying with a spray or the like.

The adhesive layer 3 preferably contains an antioxidant in order to have etching resistance. The antioxidant is not particularly limited, and examples thereof include 2,6-
Phenol-based antioxidants such as t-butyl-4-methylphenol, sulfur-based antioxidants such as dilauryl-3,3′-thiodipropionate, phosphorus-based antioxidants such as trisnonylphenylphosphide, 2- Examples thereof include benzotriazole-based antioxidants such as (2′-hydroxy-5′-methylphenyl) benzotriazole.

The adhesive layer 3 may be coated on the base material 2 to form the adhesive layer 3, or may be preliminarily formed into a sheet shape. In that case, an adhesive sheet is used as a base. The adhesive layer 3 is formed by sticking it on the upper surface of the material 2.

When the above-mentioned pressure-sensitive adhesive sheet is used, the sheet forming method is not particularly limited. For example, the adhesive is dissolved in a solvent, coated, and dried on the sheet, the adhesive containing a gas generating agent is further applied in a thickness of about a primer, or volatilization containing a gas generating agent. A pressure-sensitive adhesive sheet can be obtained by applying a volatile liquid or spraying it with a spray or the like.

In the transfer material 1 for circuit formation of this embodiment, the circuit pattern 4 is formed on the adhesive layer 3. As a method of forming the circuit pattern 4, for example, a negative resist layer is provided on the adhesive layer 3, and the negative resist layer is irradiated with ionizing radiation through a mask pattern to form a negative pattern of the circuit pattern portion. After curing the resist layer, adsorb metal ions to the circuit pattern part,
Examples include a method of forming a circuit pattern by reducing and then subjecting the resulting metal pattern portion to electroless plating and / or electrolytic plating. A specific method will be described below. A method of providing a positive type resist layer instead of the negative type resist layer can also be used. That is, a circuit pattern is formed on the adhesive layer 3 through a resist layer made of a negative resist or a positive resist.

The negative resist has a carboxyl group and / or a sulfonyl group in the molecule, and the carboxyl group and / or the sulfonyl group reacts and disappears upon irradiation with ionizing radiation, or ionization is performed. Any negative type resist may be used as long as it is crosslinked and hardened when exposed to radiation and the solubility is reduced, and is not particularly limited. For example, a resin having a carboxyl group and / or a sulfonyl group, and a photopolymerizable functional group and / or a photocrosslinkable functional group in the molecule is a main component, and a photopolymerization initiator, a sensitizer, a stabilizer, etc. With the addition of;
A compound containing a resin having a carboxyl group and / or a sulfonyl group in the molecule as a main component, and a compound having a photopolymerizable functional group and / or a compound having a photocrosslinkable functional group, a photopolymerization initiator, a sensitizer, and a stability Those obtained by adding agents and the like are preferably used. Among them, the adhesiveness to the resin forming the adhesive layer 3 is good, and the adhesiveness between the metal foil to be formed and the adhesive layer 3 can be ensured. Therefore, it is the same as or similar to the resin forming the adhesive 3 layer. It is more preferable to use a resin having a structure of These negative resists may be used alone or in combination of two or more.

The method for forming the negative resist layer on the adhesive layer 3 is not particularly limited, and for example, for example,
Examples thereof include a method of coating a negative resist on the surface of the adhesive layer using a known coater such as a comma coater, a gravure coater, a microgravure coater, and a spin coater. In addition, at this time, in order to improve the adhesion with the negative resist, the surface of the adhesive layer 3 is previously subjected to surface treatment such as corona discharge treatment, plasma treatment, electron beam irradiation treatment, sandblast treatment, embossing treatment and the like. Good. When the adhesive layer 3 is formed by coating, the negative resist layer is preferably formed after the adhesive has hardened.

The thickness of the negative resist layer is not particularly limited, but the preferred lower limit is 0.1 μm and the upper limit is 20 μm. If the thickness is less than 0.1 μm, the absolute amount of the carboxyl group and / or the sulfonyl group decreases, and a sufficient amount of metal ions cannot be adsorbed, which makes it difficult to perform electroless plating and / or electrolytic plating in a subsequent step. If it exceeds 20 μm, it may be difficult to remove the resist remaining after the circuit pattern is transferred. A more preferred lower limit is 0.2 μm and an upper limit is 10.
μm, with a more preferred lower limit of 0.5 μm and an upper limit of 5
μm.

Next, the negative resist layer is irradiated with ionizing radiation through the mask pattern to cure the negative resist layer other than the circuit pattern portion. The ionizing radiation is not particularly limited as long as it has energy capable of curing the negative resist layer by irradiation, and is not particularly limited, for example, ultraviolet rays, laser light,
Electron beams, X-rays and the like are suitable. Among them, ultraviolet rays are more preferably used. However, as these ionizing radiations, those which do not generate gas from the above-mentioned gas generating agent must be selected. Specifically, for example, when ultraviolet rays are used as the ionizing radiation, ultraviolet rays having a wavelength different from the photosensitive wavelength of the above-mentioned gas generating agent are selected.

Then, a metal salt of a carboxyl group and / or a sulfonyl group is formed on the surface of the negative resist layer by ion exchange between the carboxyl group and / or the sulfonyl group of the negative resist layer and a metal ion from the metal salt. Let The metal ion is not particularly limited, but, for example, ions of various metals such as nickel, gold, silver, copper, platinum, palladium, iron and cobalt are suitable. These metal ions may be used alone or in combination of two or more kinds. The metal salt serving as the supply source of the metal ions is not particularly limited, but, for example, nitrates, sulfates, chlorides of the above-mentioned various metals are suitable. These metal salts may be used alone or in combination of two or more kinds.

To form a metal salt of a carboxyl group and / or a sulfonyl group on the surface of the negative resist layer,
The negative resist layer is immersed in the liquid containing the metal salt. Thereby, ion exchange between the carboxyl group and / or the sulfonyl group and the metal ion in the metal salt-containing liquid occurs, and the metal salt of the carboxyl group and / or the sulfonyl group can be generated on the surface of the negative resist layer. .

The metal salt-containing liquid is generally preferably an aqueous solution, but may be an organic solvent solution such as methanol depending on the kind of the metal salt. Also,
If necessary, various additives such as a complexing agent and a surfactant may be added to the metal salt-containing liquid. The concentration of the metal ion in the metal salt-containing liquid is not particularly limited, but the preferable lower limit is 0.01 mo.
1 / L, the upper limit is 1 mol / L, the more preferable lower limit is 0.03 mol / L, and the upper limit is 0.1 mol / L. When a plurality of metal salts (metal ions) are used, the total concentration of metal ions may be set within the above range.

Immersion of the negative resist layer in the metal salt-containing liquid may be performed in a stationary state or may be performed in a stirring state using a stirring blade or the like. Although not particularly limited, the preferable lower limit of the immersion temperature is 1
0 ° C, the upper limit is 40 ° C, and the more preferable lower limit is 20 ° C.
C., the upper limit is 30.degree. The lower limit of the immersion time is preferably 1 minute, the upper limit thereof is 30 minutes, the more preferable lower limit thereof is 2 minutes, and the upper limit thereof is 20 minutes.

Next, the metal salt of the carboxyl group and / or the sulfonyl group formed on the surface of the negative resist layer is reduced to form a metal pattern on the surface of the negative resist layer. The method of reducing the metal salt is not particularly limited, but, for example, a method of reducing with a reducing agent, a method of reducing with a catalyst and energy such as ultraviolet rays, and the like are suitable. These reducing methods may be used alone or in combination of two or more.

The reducing agent is not particularly limited, and examples thereof include sodium borohydride, potassium borohydride, dimethylamine borane, trimethylamine borane, hydrazine, formaldehyde and its derivatives, sulfite salts such as sodium sulfite, and sodium hypophosphite. And the like. These reducing agents may be used alone or in combination of two or more kinds.

Finally, the circuit pattern 4 is formed by subjecting the metal coating formed on the surface of the negative resist layer to electroless plating and / or electrolytic plating. The method of electroless plating or electrolytic plating is not particularly limited, and a conventionally known method may be used. For example, metal salts, complexing agents, reducing agents,
It can be performed by immersing the reduction-treated negative resist layer in a plating solution containing components such as a stabilizer, an accelerator, a brightener, a surfactant, a buffer, and a pH adjuster.
As the plating liquid, a commercially available one may be used.

As the above-mentioned metal salt, an appropriate soluble metal salt may be used according to the kind of the desired metal, and is not particularly limited. The above metal salts may be used alone or 2
More than one kind may be used in combination.

The complexing agent is not particularly limited,
For example, lactic acid, oxalic acid, malic acid, tartaric acid, citric acid, thioglycolic acid, ammonia, glycine, asparagine, ethylenediamine, ethylenediaminetetraacetic acid,
Various compounds having a complexing action on metal ions such as Rochelle acid and succinimide are preferably used. These complexing agents may be used alone or in combination of two or more kinds.

The reducing agent is not particularly limited,
For example, sodium phosphinate, sodium borohydride, potassium borohydride, dimethylamine borane, hydrazine, formalin, imidazole and the like are preferably used. These reducing agents may be used alone or in combination of two or more.

The buffering agent is not particularly limited,
For example, carboxylic acids such as acetic acid and citric acid; inorganic salts such as boric acid and carbonic acid; or alkali metal salts thereof are preferably used. These buffer agents may be used alone or in combination of two or more kinds.

The stirring method for applying the electroless plating is not particularly limited, and conventionally known methods such as blade stirring, stirrer, homogenizer, mixer, ultrasonic dispersion, and air stirring can be used.

The circuit pattern 4 finally constitutes the circuit pattern of the circuit board. Circuit pattern 4 above
The material constituting the is not particularly limited, for example,
Examples of the metal include copper, silver, gold, aluminum, and alloys thereof. In the present embodiment, a flexible metal foil made of copper is used.

The thickness of the circuit pattern 4 is not particularly limited, but an insulating substrate or a ceramic green sheet that can form a circuit pattern having sufficient conductivity and that constitutes an insulating substrate of a circuit substrate described later. The thickness is preferably 5 to 200 μm in order to be stably joined.

The circuit-forming transfer material 1 according to this embodiment is characterized in that the base material 2, the adhesive layer 3 and the circuit pattern 4 are laminated as described above. Next, an embodiment of a method of manufacturing a circuit board using the transfer material 1 for circuit formation will be described.

An insulating substrate 5 is placed on the circuit pattern 4 as shown in FIG. 2 and hot pressed in this state. As the insulating substrate 5, an appropriate organic resin or an organic resin-containing composite material which is an insulating material forming a circuit board and is brought into close contact with the circuit pattern 4 by hot pressing can be used.

In this embodiment, the insulating substrate 5 is made of a thermosetting resin in a semi-cured state. Examples of such thermosetting resin include polyphenylene ether, epoxy resin, polyvinylidene ether resin, BT resin, bismaleade triazine,
Examples thereof include polyimide, fluororesin, phenol resin, polyaminobismaleimide and the like. The insulating substrate 5 may be made of a composite material of the thermosetting resin in the semi-cured state and an inorganic material such as glass or an organic material.

By the above heat press, the circuit pattern 4 is
Most of it sinks into the insulating substrate 5, and when the temperature decreases over time, it is firmly bonded to the insulating substrate 5.

As shown in FIG. 3, after the circuit pattern 4 is bonded to the insulating substrate 5 by hot pressing, in the present embodiment, the adhesive layer 3 is exposed to light having a wavelength that activates the above-mentioned photopolymerization initiator. Alternatively, heat at a temperature for activating the thermal polymerization initiator is applied to cure the post-curable adhesive, and at the same time, gas is generated from the gas generating agent.

Due to the curing of the post-curable adhesive and the generation of gas, the adhesive force of the adhesive layer 3 to the circuit pattern 4 is lower than that before the stimulation is applied, and the adhesive force to the base material 2 is lower than that of the adhesive layer 3. Get lower. Although the insulating substrate 5 and the adhesive layer 3 are also brought into close contact with each other by hot pressing, the adhesive force between the insulating substrate 5 and the adhesive layer 3 is also reduced due to the curing of the post-curable adhesive and the generation of gas. In this embodiment, the adhesive layer 3 was stimulated after the hot pressing, but before the insulating substrate 5 is hot pressed, the adhesive layer 3 is stimulated to cure the post-curable adhesive. Gas may be generated.

Therefore, when the curing of the post-curable adhesive and the generation of gas in the adhesive layer 3 are completed, the circuit pattern 4 is formed.
The peel strength from the adhesive layer 3 is lower than the peel strength of the circuit pattern 4 from the insulating substrate 5.

Therefore, the circuit pattern 4 firmly bonded to the insulating substrate 5 can be easily peeled off from the upper surface of the adhesive layer 3, and the circuit substrate 6 shown in FIG. 4 can be obtained. On the circuit board 6, the circuit pattern 4 is formed on one surface of the insulating substrate 5.

If necessary, a plurality of circuit boards 6 obtained as described above may be laminated and hot pressed to obtain a multilayer board. In the method of manufacturing a circuit board of the present embodiment, the patterned circuit pattern 4 is transferred to the insulating substrate 5 as in the conventional transfer method. Therefore, since the insulating substrate 5 is not exposed to the chemicals when forming the circuit pattern 4, deterioration of the insulating substrate 5 can be suppressed.

Although part of the negative resist layer may be transferred to the circuit board 6 after transfer, the remaining negative resist layer may be treated with a resist remover, chemical etching, plasma etching, etc. Can be removed by.

In the embodiment of the method for manufacturing the circuit board described above,
Although the insulating substrate 5 is used, in the present invention, a ceramic green sheet may be used instead of the insulating substrate.
That is, in the above embodiment, the transfer material 1 for forming a circuit is formed.
In place of the insulating substrate 5, a ceramic green sheet is brought into close contact with the circuit pattern 4 by hot pressing. In this case, the binder resin in the ceramic green sheet is softened, and the ceramic green sheet and the circuit pattern 4 are firmly joined by cooling with time after hot pressing. Further, in order to improve the adhesiveness between the ceramic green sheet and the circuit pattern 4, a resin having good adhesiveness with the binder resin in the ceramic green sheet may be applied to the surface of the circuit pattern 4 before hot pressing. .

After that, by stimulating the adhesive layer 3 in the same manner as in the above-described embodiment, the bonding strength between the adhesive layer 3 and the circuit pattern 4 is greater than the bonding strength between the adhesive layer 3 and the base material 2. Will also be lower. Therefore, the adhesive layer 3 may be peeled off from the circuit pattern 4 together with the base material 2.

As described above, the transfer material for forming a circuit according to the present invention can be applied not only to an insulating substrate but also to the production of a circuit substrate using a ceramic green sheet as a substrate material.

A circuit board can be obtained by firing a ceramic green sheet having a circuit pattern obtained by transferring a circuit pattern to the ceramic green sheet, but a plurality of ceramic green sheets having the circuit pattern transferred thereto can be obtained. It is also possible to obtain a ceramic multi-layer substrate by laminating the sheets, pressing them and then firing them.

[0072]

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 <Manufacture of Transfer Material for Circuit Formation> A. Production of pressure-sensitive adhesive layer The following compound was dissolved in ethyl acetate and irradiated with ultraviolet rays for polymerization to obtain an acrylic copolymer having a weight average molecular weight of 700,000. To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained acrylic copolymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate was added and reacted, and the resin of the ethyl acetate solution after the reaction was further added. Solid content 100
20 parts by weight of pentaerythritol triacrylate, photopolymerization initiator (Irgacure 651) based on parts by weight
0.5 parts by weight of polyisocyanate and 1.5 parts by weight of polyisocyanate were mixed to prepare an ethyl acetate solution of a photocurable pressure-sensitive adhesive (hereinafter, also referred to as pressure-sensitive adhesive (1)). Butyl acrylate 79 parts by weight Ethyl acrylate 15 parts by weight Acrylic acid 1 part by weight 2-Hydroxyethyl acrylate 5 parts by weight Photoinitiator 0.2 parts by weight (Irgacure 651, 50% ethyl acetate solution) Lauryl mercaptan 0.02 parts by weight

2,2'-azobis- (N-) was added to 100 parts by weight of the resin solid content of the adhesive (1) ethyl acetate solution.
Butyl-2-methylpropionamide) 100 parts by weight,
Then, 2 parts by weight of benzotriazole were mixed to prepare an ethyl acetate solution of a photocurable pressure-sensitive adhesive containing a gas generating agent (hereinafter, also referred to as pressure-sensitive adhesive (2)).

An ethyl acetate solution of the pressure sensitive adhesive (1) was applied to a corona-treated transparent polyethylene terephthalate (PET) film having a thickness of 38 μm and a dry film having a thickness of about 10 μm. The coating solution was dried with a doctor knife so that the coating solution was heated to 110 ° C. for 5 minutes to volatilize the solvent and dry the coating solution. The dried pressure-sensitive adhesive layer exhibited tackiness in a dry state.

On the other hand, the ethyl acetate solution of the adhesive (2) was
A 38 μm-thick PET film whose surface has been subjected to a mold release treatment is applied by a bar coater so that the thickness after drying is 5 μm, and heated at 110 ° C. for 5 minutes to volatilize the solvent and produce an adhesive agent. The layers were dried. Next, the pressure-sensitive adhesive (1) formed on the PET film having one surface subjected to corona treatment
The layer and the pressure-sensitive adhesive (2) layer formed on the PET film subjected to the mold release treatment were attached.

B. Preparation of negative resist layer 4,4'- was added to 100 g of dehydrated N-methylpyrrolidone.
45 g of diaminodiphenyl ether was dissolved, 55 g of pyromellitic acid was added thereto little by little at room temperature with stirring to dissolve, and further stirred at room temperature for 5 hours to synthesize a polyamic acid. To 50 g of the obtained polyamic acid, 0.25 g of dimethylaminoethyl acrylate and 0.2 g of a photopolymerization initiator (Kyoei Chemical Co., Ltd., Irgacure 184) were added, thoroughly mixed, and then degassed by heating to contain a carboxyl group. A negative polyimide resist solution was prepared.

On the release-treated PET film, the obtained carboxyl group-containing negative polyimide resist solution was applied so that the resin thickness after drying was 2 μm, and dried to obtain a negative resist layer. It was

P prepared by corona treatment on one side prepared in A
The adhesive agent (1) layer formed on the ET film and the adhesive agent (2) layer formed on the PET film subjected to the mold release treatment were bonded together, and then the mold release treatment was applied. After peeling off the PET film, an adhesive (2) layer,
The release-processed PET film prepared in B was attached so as to come into contact with the negative resist layer.

C. Circuit pattern formation The release-treated PET film on the side of the negative resist layer was peeled off, and a width of 50 μ was formed at a pitch of 50 μm on the PET film.
An exposure with an ultra-high pressure mercury lamp through 100 mask patterns (wiring patterns) of m, the circuit pattern portion is shielded by metal vapor deposition, and a mask pattern made of quartz glass in which an opening is provided in a portion other than the circuit pattern portion is used. The negative resist layer was irradiated with ultraviolet rays at an intensity of 500 mJ / cm ² for 1 minute by using a machine (manufactured by Mikasa Co., Ltd., Mask Aligner MA-10). Next, after immersing in a 0.05 mol / L copper sulfate aqueous solution for 3 minutes at room temperature to adsorb copper ions,
It was immersed in a 0.005 mol / L sodium borohydride aqueous solution at room temperature for 1 minute to reduce copper ions. This was immersed in an electroless plating solution (OPC-720 manufactured by Okuno Chemical Industries Co., Ltd.) at room temperature for 15 minutes to perform electroless plating, and the thickness was 12 μm.
m copper circuit pattern was formed. Then 40 for 3 days
It was aged at 0 ° C. to obtain a transfer material for circuit formation.

<Production of Circuit Board> The circuit-formed surface of the obtained transfer material for circuit formation was brought into close contact with the thermosetting polyphenylene ether prepreg sheet, and pressure-pressed for 1 minute while heating at 130 ° C. It was After releasing the press pressure and returning it to room temperature, an ultraviolet ray of 365 nm was irradiated at an intensity of 40 mW / cm ² using an ultra-high pressure mercury lamp from the PET side.
The illuminance was adjusted so that Next, the peeled circuit pattern was transferred to the prepreg so that the adhesive layer and the circuit pattern were peeled off to obtain a circuit board. here,
All the transfer was good, and no fine lines remained on the pressure-sensitive adhesive layer without transfer.

(Example 2) <Production of transfer material for circuit formation> The following compounds were dissolved in ethyl acetate and irradiated with ultraviolet rays to carry out polymerization to obtain an acrylic copolymer having a weight average molecular weight of 700,000. To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained acrylic copolymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate was added and reacted, and the resin of the ethyl acetate solution after the reaction was further added. 20 parts by weight of pentaerythritol triacrylate, 0.5 parts by weight of a photopolymerization initiator (Irgacure 651), 1.5 parts by weight of polyisocyanate, and 1.2 parts by weight of benzotriazole were mixed with 100 parts by weight of the solid content, and light was added. An ethyl acetate solution of a curable pressure-sensitive adhesive (hereinafter, also referred to as pressure-sensitive adhesive (3)) was prepared. Butyl acrylate 79 parts by weight Ethyl acrylate 15 parts by weight Acrylic acid 1 part by weight 2-Hydroxyethyl acrylate 5 parts by weight Photoinitiator 0.2 parts by weight (Irgacure 651, 50% ethyl acetate solution) Lauryl mercaptan 0.02 parts by weight

An ethyl acetate solution of the pressure-sensitive adhesive (3) was applied to the corona-treated surface of a transparent polyethylene terephthalate (PET) film having a thickness of 38 μm and corona-treated on one side to give a dry film thickness of about 10 μm. The coating solution was dried with a doctor knife so that the coating solution was heated to 110 ° C. for 5 minutes to volatilize the solvent and dry the coating solution. The dried pressure-sensitive adhesive layer exhibited tackiness in a dry state.

On the layer of this pressure-sensitive adhesive (3), 2,2'-azobis- (N-butyl-2-methylpropionamide) was added.
The methyl ethyl ketone solution prepared to have a concentration of 5% by weight was evenly sprayed until the surface of the adhesive (3) layer was sufficiently wet. After spraying was repeated 3 times, heating was performed at 110 ° C. for 5 minutes. As a result, pale yellow precipitated particles of 2,2′-azobis- (N-butyl-2-methylpropionamide) were attached to the surface of the pressure-sensitive adhesive (3) layer.

Then, on the surface of the pressure-sensitive adhesive (3) layer to which the deposited particles adhered, a thickness of 1 was obtained by the same method as in Example 1.
After forming a 2μm copper circuit pattern, 40 ℃ for 3 days
Then, a transfer material for circuit formation was obtained.

<Production of Circuit Board> Using the obtained transfer material for circuit formation, a circuit board was obtained in the same manner as in Example 1.
Here, all the transfer was good, and no fine lines remained on the pressure-sensitive adhesive layer without being transferred.

Example 3 <Production of Transfer Material for Circuit Formation> The following compounds were dissolved in ethyl acetate and irradiated with ultraviolet rays to carry out polymerization to obtain an acrylic copolymer having a weight average molecular weight of 700,000. To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained acrylic copolymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate was added and reacted, and the resin of the ethyl acetate solution after the reaction was further added. 20 parts by weight of pentaerythritol triacrylate, 0.5 parts by weight of a photopolymerization initiator (Irgacure 651), 1.5 parts by weight of polyisocyanate, 1.2 parts by weight of benzotriazole, and 2 parts by weight of 100 parts by weight of solid content. , 2′-Azobis- (N-butyl-2-methylpropionamide) was mixed with 100 parts by weight to prepare an ethyl acetate solution of a photocurable pressure-sensitive adhesive (hereinafter, also referred to as pressure-sensitive adhesive (4)). Butyl acrylate 79 parts by weight Ethyl acrylate 15 parts by weight Acrylic acid 1 part by weight 2-Hydroxyethyl acrylate 5 parts by weight Photoinitiator 0.2 parts by weight (Irgacure 651, 50% ethyl acetate solution) Lauryl mercaptan 0.02 parts by weight

An ethyl acetate solution of the pressure-sensitive adhesive (4) was applied to the corona-treated surface of a transparent polyethylene terephthalate (PET) film having a thickness of 38 μm and corona-treated on one surface to give a dry film thickness of about 10 μm. The coating solution was dried with a doctor knife so that the coating solution was heated to 110 ° C. for 5 minutes to volatilize the solvent and dry the coating solution. The dried pressure-sensitive adhesive layer exhibited tackiness in a dry state. Then, a 12 μm-thick copper circuit pattern was formed on the surface of the pressure-sensitive adhesive (4) layer by the same method as in Example 1, and then cured at 40 ° C. for 3 days to obtain a transfer material for circuit formation. .

<Manufacture of Circuit Board> Using the obtained transfer material for forming a circuit, a circuit board was obtained in the same manner as in Example 1.
Here, all the transfer was good, and no fine lines remained on the pressure-sensitive adhesive layer without being transferred.

(Example 4) <Production of transfer material for circuit formation> The following compounds were dissolved in ethyl acetate and irradiated with ultraviolet rays for polymerization to obtain an acrylic copolymer having a weight average molecular weight of 700,000. To 100 parts by weight of the resin solid content of the ethyl acetate solution containing the obtained acrylic copolymer, 3.5 parts by weight of 2-isocyanatoethyl methacrylate was added and reacted, and the resin of the ethyl acetate solution after the reaction was further added. 20 parts by weight of pentaerythritol triacrylate, 0.5 parts by weight of a photopolymerization initiator (Irgacure 651), and 1.5 parts by weight of polyisocyanate are mixed with 100 parts by weight of a solid content to prepare an adhesive (5) ethyl acetate solution. Was prepared. Butyl acrylate 79 parts by weight Ethyl acrylate 15 parts by weight Acrylic acid 1 part by weight 2-Hydroxyethyl acrylate 5 parts by weight Photoinitiator 0.2 parts by weight (Irgacure 651, 50% ethyl acetate solution) Lauryl mercaptan 0.02 parts by weight

100 parts by weight of the resin solid content of the ethyl acetate solution of the adhesive (5) was mixed with 100 parts by weight of 3-azidomethyl-3-methyloxetane and 2 parts by weight of benzotriazole to give an azide compound. An ethyl acetate solution containing the adhesive (6) was prepared.

An ethyl acetate solution of the adhesive (5) was applied to a corona-treated transparent polyethylene terephthalate (PET) film having a thickness of 38 μm and a dry film having a thickness of about 10 μm. Was coated with a doctor knife to evaporate the solvent and the coating solution was dried. The dried pressure-sensitive adhesive layer exhibited tackiness in a dry state.

On the other hand, the ethyl acetate solution of the adhesive (6) was
A 38 μm-thick PET film having a surface subjected to a release treatment was applied so that the thickness after drying using a bar coater would be 5 μm, and the solvent was volatilized to dry the pressure-sensitive adhesive layer.

A pressure-sensitive adhesive (5) layer formed on a PET film having one surface subjected to corona treatment and a pressure-sensitive adhesive (6) layer formed on a PET film subjected to release treatment were bonded together. After that, P which has been subjected to release treatment from the adhesive (6) layer
The ET film was peeled off, and a copper circuit pattern having a thickness of 12 μm was formed by the same method as in Example 1, and then 4 days for 3 days.
It was aged at 0 ° C. to obtain a transfer material for circuit formation.

<Manufacture of Circuit Board> Using the obtained transfer material for forming a circuit, a circuit board was obtained in the same manner as in Example 1.
Here, all the transfer was good, and no fine lines remained on the pressure-sensitive adhesive layer without being transferred.

Example 5 <Manufacture of Transfer Material for Circuit Formation> The ethyl acetate solution of the adhesive (1) prepared in Example 1 was corona-treated on one side to obtain a transparent polyethylene terephthalate (thickness: 38 μm). P
The ET) film was coated on the corona-treated surface with a doctor knife so that the thickness of the dried film was about 10 μm, and heated at 110 ° C. for 5 minutes to evaporate the solvent and dry the coating solution. The dried pressure-sensitive adhesive layer exhibited tackiness in a dry state.

On the other hand, the ethyl acetate solution of the pressure-sensitive adhesive (2) prepared in Example 1 was subjected to release treatment on the surface to a thickness of 38.
A μm PET film was coated with a bar coater so that the thickness after drying was 5 μm, and heated at 110 ° C. for 5 minutes to volatilize the solvent and dry the pressure-sensitive adhesive layer.

A pressure-sensitive adhesive (1) layer formed on a PET film having one surface subjected to corona treatment and a pressure-sensitive adhesive (2) layer formed on a PET film subjected to mold release treatment were bonded together. After that, P which has been released from the pressure-sensitive adhesive (2) layer
The ET film was peeled off, and a copper circuit pattern having a thickness of 12 μm was formed by the same method as in Example 1, and then 4 days for 3 days.
It was aged at 0 ° C. to obtain a transfer material for circuit formation.

<Production of Circuit Board> Using the obtained transfer material for circuit formation, a circuit board was obtained in the same manner as in Example 1.
Here, all the transfer was good, and no fine lines remained on the pressure-sensitive adhesive layer without being transferred.

[0100]

EFFECTS OF THE INVENTION In the circuit-forming rolling material according to the present invention, an adhesive layer is formed on a base material, which is hardened and gas is generated by stimulus, and the adhesive force to the metal foil is lower than that before the stimulus is applied. And a circuit pattern is formed on the adhesive layer. Therefore, before or after hot-pressing the insulating substrate or the ceramic green sheet, by stimulating the adhesive layer to reduce the adhesive force, the circuit pattern fixed to the insulating substrate or the ceramic green sheet is removed from the circuit pattern. The adhesive layer supported by the material can be easily peeled off. That is, the peeling strength between the adhesive layer and the circuit pattern decreases due to the curing of the post-curable adhesive in the adhesive layer and the generation of gas from the gas generating agent, so that the adhesive layer can be easily and easily removed from the circuit pattern. Can be peeled off.

Therefore, when the transfer material for forming a circuit according to the present invention is used, the circuit board can be easily and stably manufactured by the transfer method according to the method for manufacturing a circuit board according to the present invention, and a circuit pattern Even when the miniaturization advances and the line width of the circuit pattern portion becomes thin, the peeling strength between the adhesive layer and the circuit pattern is reduced, so that the circuit pattern can be transferred stably and the thermal stress causes It is possible to obtain a circuit board that is less likely to be distorted and has excellent reliability, and it is possible to cope with higher density and narrower width of the circuit board.

When the insulating substrate is made of a thermosetting resin in a semi-cured state by the manufacturing method according to the present invention, the thermosetting resin is cured to have excellent strength and dimensional stability. A circuit board having excellent accuracy can be obtained by using an excellent insulating substrate.

[Brief description of drawings]

FIG. 1 is a sectional view showing a transfer material for forming a circuit according to an embodiment of the present invention.

FIG. 2 is a sectional view for explaining a step of placing an insulating substrate on a circuit pattern in the manufacturing method according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view for explaining a state where an insulating substrate is hot-pressed onto a circuit pattern in the manufacturing method according to the embodiment of the present invention.

FIG. 4 is a cross-sectional view illustrating a circuit board obtained by a manufacturing method according to an embodiment of the present invention.

[Explanation of symbols]

1 ... Transfer material for circuit formation 2 ... Base material 3 ... Adhesive layer 4 ... Circuit pattern 5 ... Insulating substrate 6 ... Circuit board

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shigeru Dangami             Sekisui Chemical, 2-1 Hyakusan, Shimamoto-cho, Mishima-gun, Osaka Prefecture             Industry Co., Ltd. (72) Inventor Yasuhiko Oyama             Sekisui Chemical, 2-1 Hyakusan, Shimamoto-cho, Mishima-gun, Osaka Prefecture             Industry Co., Ltd. F term (reference) 5E343 AA23 BB24 CC01 DD33 DD56                       DD63 GG11

Claims (7)

[Claims] 1. A transfer material for forming a circuit, which is used for transferring a circuit pattern to a semi-cured insulating substrate or a ceramic green sheet, which comprises a base material and a transfer material provided on the base material. And a circuit pattern characterized by comprising an adhesive layer containing a gas generating agent for generating a gas by stimulation and having an adhesive strength reduced by stimulation, and a circuit pattern formed on the adhesive layer. Transfer material. 2. A transfer material for forming a circuit, which is used for transferring a circuit pattern to an insulating substrate in a semi-cured state or a ceramic green sheet, which is a base material and is provided on the base material. And an adhesive layer that contains a gas generating agent that generates a gas when stimulated by light, and has an adhesive force that is reduced by the stimulation by light, and a circuit pattern formed on the adhesive layer. Transfer material for circuit formation. 3. A transfer material for forming a circuit, which is used for transferring a circuit pattern to an insulating substrate in a semi-cured state or a ceramic green sheet, the base material being provided on the base material. And an adhesive layer containing a gas generating agent that generates a gas by heat stimulation, and having an adhesive strength reduced by heat stimulation, and a circuit pattern formed on the adhesive layer. Transfer material for circuit formation. 4. The transfer material for circuit formation according to claim 1, 2 or 3, wherein the adhesive layer contains a gas generating agent only in the surface layer portion. 5. The transfer material for circuit formation according to claim 1, 2, 3 or 4, wherein the adhesive has thermoplasticity. 6. A method of manufacturing a circuit board using the circuit-forming transfer material according to claim 1, 2, 3, 4, or 5, comprising: preparing the circuit-forming transfer material; and forming the circuit. Heat-pressing a semi-cured insulating substrate or ceramic green sheet on the circuit pattern of the transfer material for printing, and stimulating the adhesive layer on the circuit-forming transfer material before or after the hot pressing. And a step of lowering the adhesive force to the circuit pattern as compared with before giving a stimulus, and after reducing the adhesive force of the adhesive layer, peeling the circuit pattern from the adhesive layer, the circuit pattern To the insulating substrate or the ceramic green sheet. 7. The method for manufacturing a circuit board according to claim 3, wherein the insulating substrate in a semi-cured state is made of a thermosetting resin in a semi-cured state.