KR101682887B1 - Film with metal film - Google Patents

Abstract

The present invention relates to a method of manufacturing a circuit board which can efficiently form a metal film layer having excellent adhesion and uniformity to an insulating layer and the insulating layer, and further, has excellent laser processability in formation of a blind via by a laser; And a metal film-attaching film and a metal film-attaching adhesive film to be used in the method. A metal film-attached film having a support layer, a release layer formed on the support layer, and a metal film layer formed on the release layer, wherein at least the surface of the release layer that is in contact with the metal film layer is a water-soluble cellulose resin, And a water-soluble acrylic resin, and the water-soluble resin contains at least one selected from the group consisting of metal compounds, carbon powder, metal powder and black dye. ; Or an adhesive film with a metal film on which a curable resin composition is formed on a metal film layer of the metal film attachment film is used.

Description

[0001] The present invention relates to a film with metal film,

The present invention relates to a metal film deposition film and a metal film deposition film. Further, the present invention relates to a method of manufacturing a circuit board such as a multilayer printed wiring board using these films.

Conventionally, a method of transferring a metal film layer such as a copper film as a plating seed layer onto an adherend has been attempted. For example, in Patent Documents 1 and 2, a metal film-attached film in which a copper film is formed by vapor deposition or the like is formed on a support via a release layer, and the copper film of the metal film- Or a prepreg surface, and a conductor layer is formed on the transferred copper film by plating or the like. Patent Document 3 discloses an adhesive film in which a copper film is formed directly on a support by vapor deposition or the like, and a resin composition layer is formed thereon.

However, in the methods of Patent Documents 1 and 2, since the peelability of the polyethylene terephthalate (hereinafter, abbreviated as "PET") film from the metal film is deteriorated, transfer of the uniform metal film becomes difficult. Further, in the method described in Patent Document 3, since the support of the adhesive film does not have a release layer, it is difficult to form a uniform metal film layer, such as wrinkles or damage to the metal film layer.

Further, in the case of forming a blind via with a laser in the insulating layer to which the metal film is transferred, since the laser beam is reflected by the metal film, there is a problem that the workability is poor. If the laser energy is increased to increase the workability, there is a problem that the underlying metal layer is damaged and the shape of the blind via tends to deteriorate. Therefore, improvement in workability at the lowest possible laser energy is required. For example, as a method of performing a perforation process by a laser from a metal layer such as a metal laminate, a laser energy absorbing sheet having an adhesive layer is adhered on a metal layer, and the sheet is peeled Although the method is known, there is a problem that process and cost increase. In addition, the transferred thin metal film has a problem that the metal film is liable to be damaged when the laser energy absorbing sheet is peeled off.

Patent Document 1: JP-A-2004-230729 Patent Document 2: JP-A-2002-324969 Patent Document 3: JP-A-9-296156

Disclosure of the Invention It is an object of the present invention to provide a method for producing a circuit board which can easily peel a support from a metal film layer formed on an insulating layer and is excellent in laser processability in formation of a blind via by a laser, And an adhesive film with a metal film.

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that, by forming a specific release layer in a metal film adhesive film and a metal film adhesive film, Respectively. Further, it has been found that by laser irradiation from a specific release layer, the laser processability of the blind via in the insulating layer in which the metal film layer is in close contact is improved, and the present invention has been accomplished.

That is, the present invention includes the following contents.

(1) A metal film-attached film having a support layer, a release layer formed on the support layer, and a metal film layer formed on the release layer, wherein at least the surface of the release layer contacting the metal film layer is a water- Wherein the water-soluble resin is at least one selected from a water-soluble resin selected from a water-soluble acrylic resin and a water-soluble resin, and the water-soluble resin contains at least one selected from a metal compound powder, Metal film adhesion film.

(2) The water-soluble polyester resin according to (1), wherein the water-soluble polyester resin is a water-soluble polyester having a sulfo group or a salt thereof and / or a carboxyl group or a salt thereof, / RTI >

(3) The metal film according to item (1) or (2), wherein the water-soluble resin contains at least one selected from the group consisting of metal compounds, carbon powder, metal powder, and black dye in a proportion of 0.05 to 40% Attachment film.

(4) The metal film-attached film according to any one of (1) to (3), wherein the support layer is a plastic film.

(5) The metal film-attached film according to any one of (1) to (3), wherein the support layer is a polyethylene terephthalate film.

(6) A metal film-adhering method according to any one of (1) to (5), wherein the metal film layer is formed by at least one method selected from vapor deposition, sputtering and ion plating film.

(7) The adhesive film with a metal film according to any one of (1) to (6), wherein the metal film layer is formed of copper.

(8) The metal film according to any one of (1) to (7), wherein the metal film layer is formed by forming a copper layer, a chromium layer, a nickel-chromium alloy layer or a titanium layer in this order on the water- , Adhesive film with metal film.

(9) The metal film-attached film according to any one of (1) to (8), wherein the thickness of the metal film layer is 50 nm to 5000 nm.

(10) The metal film-attached film according to any one of (1) to (9), wherein the layer thickness of the release layer is from 0.1 m to 20 m.

(11) The metal film-attached film according to any one of (1) to (10), wherein the layer thickness of the support layer is 10 μm to 70 μm.

(12) An adhesive film with a metal film, wherein a layer of a curable resin composition is formed on a metal film layer of the film having a metal film according to any one of (1) to (11).

(13) The adhesive film with a metal film according to (12), wherein the curable resin composition layer is a prepreg impregnated in a sheet-like reinforcing base material made of fibers.

(14) The metal film-attached film according to any one of (1) to (11) above is laminated on the curable resin composition layer formed on the inner layer circuit board so that the metal film layer is in contact with the surface of the curable resin composition layer, The adhesive film with a metal film according to the above (12) or (13) is laminated so that the curable resin composition layer is in contact with the surface of the inner layer circuit board, the curable resin composition is cured to form an insulating layer, And a step of irradiating a laser beam onto the release layer formed of a water-soluble resin present on the metal film layer to form a blind via.

(15) A method according to (14), further comprising a step of dissolving and removing the release layer formed of a water-soluble resin present on the metal film layer after forming the blind via, in an aqueous solution.

(16) The method according to (14) or (15), wherein the laser is a carbon dioxide gas laser.

(17) The method according to any one of (14) to (16), further comprising a step of forming a conductor layer on the metal film layer by plating.

The " circuit board " in the present invention is not particularly limited as long as it has an insulating layer and a circuit-formed conductor layer, and includes various circuit boards such as a multilayer printed wiring board and a flexible printed wiring board. In addition, in the case of the "inner layer circuit board" in particular, the circuit board is patterned and processed on one or both surfaces of a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate and a thermosetting polyphenylene ether substrate (Circuit formed) conductor layer, and in the case of producing a circuit board, also an intermediate product in which an insulating layer and a conductor layer are to be formed.

According to the present invention, by forming a specific release layer in a metal film-adhering film or a metal film-adhering adhesive film, when a circuit board is manufactured, the support easily peels from the metal film adhered on the cured product of the curing resin composition , And then the water-soluble resin release layer present on the metal film layer can be dissolved and removed in an aqueous solution, so that the dynamic load acting on the metal film layer is small and a uniform metal film layer can be formed. In addition, since a metal film layer having high adhesiveness is formed on the surface of the extremely smooth insulating layer (cured layer), it is possible to manufacture a circuit board suitable for micro wiring. Further, it has been found that in the formation of blind vias into an insulating layer in which a metal film is closely adhered, workability of the blind via is improved by laser irradiation from a specific release layer. That is, a circuit board suitable for micro-wiring is provided as a method having excellent productivity and economy.

The present invention is a specific metal film deposition film, a metal film deposition film, and a method for producing a circuit board using the same.

[Support layer]

The support layer is a film or sheet having a self-supporting property, and a metal foil or a plastic film can be used. In particular, a plastic film is suitably used. Examples of the metal foil include aluminum foil and copper foil. In the case where a metal foil is used as a support layer and the metal film-attached film does not have a release layer, a metal foil made of a metal different from the metal film layer to be formed is employed. Examples of the plastic film include a polyethylene terephthalate film, a polyethylene naphthalate film, a polyimide film, a polyamideimide film, a polyamide film, a polytetrafluoroethylene film and a polycarbonate film, and a polyethylene terephthalate film, a polyethylene naphthalate A film is preferable, and among these, an inexpensive polyethylene terephthalate film is particularly preferable. The surface of the support may be subjected to a surface treatment such as a mat treatment or a corona treatment.

The layer thickness of the support layer is 10 탆 to 70 탆, preferably 15 탆 to 70 탆 from the viewpoint of ensuring cost-effective practicality. If the layer thickness is too small, there is a problem that the handling property is inferior, the separation of the support layer is poor, and the formation of a smooth metal film layer is defective. The surface of the support contacting the curable resin composition layer may be subjected to surface treatment such as corona treatment. The surface of the support not in contact with the curable resin composition layer may be subjected to a surface treatment such as a mat treatment or a corona treatment.

The surface of the support layer on the side where the release layer is formed preferably has an arithmetic average roughness Ra of 50 nm or less (0 or more and 50 nm or less), further preferably 40 nm or less, further preferably 35 nm or less from the viewpoint of prevention of cracking during production of the metal film- , Further preferably 30 nm or less. The arithmetic mean roughness (Ra value) can be measured by a known method, for example, by using a device such as a non-contact surface roughness meter (WYKO NT3300; manufactured by Veeco Instruments Inc.). When the support is a plastic film, the Ra value is preferably 5 nm or more, more preferably 10 nm or more, in order to facilitate winding of the film after the release layer or the metal film layer is formed. The arithmetic mean roughness (Ra) of the surface of the plastic film on the side where the release layer is not formed is not particularly limited. However, when the metal film-attached film is rolled into a roll shape, There is a risk of causing cracks to come into contact with each other. For example, if the thickness is within the above range, there is no fear of such defects.

For example, T60 (polyethylene terephthalate film, Ra = 22 nm, manufactured by Toray Industries, Inc.), A4100 (polyethylene terephthalate film, smooth surface side Ra = 12 nm, Toyobo Co Ltd., Q83 (polyethylene naphthalate film, smooth surface side Ra = 32 nm, manufactured by Teijin DuPont Films Japan Limited).

[Release Layer]

The release layer according to the present invention is characterized in that at least the surface in contact with the metal film layer is formed of at least one water-soluble resin selected from a water-soluble cellulose resin, a water-soluble polyester resin and a water-soluble acrylic resin, Carbon powder, metal powder, and black dye. The water-soluble resin is more preferably a water-soluble cellulose resin and a water-soluble polyester resin, particularly a water-soluble cellulose resin. Further, the water-soluble polyester resin is preferably a water-soluble polyester having a sulfo group or a salt thereof and / or a carboxyl group or a salt thereof because of good peelability. Further, the water-soluble acrylic resin is preferably a water-soluble acrylic resin having a carboxyl group or a salt thereof because of good releasability.

Usually, the release layer formed of a water-soluble resin is formed as a single layer, but a multi-layer structure in which the water-soluble resin used is formed of two or more different layers may be used. In the present invention, as the release layer, another release layer formed of a silicone resin, an alkyd resin, a fluororesin or the like may be present between the water-soluble resin release layer and the support layer in order to improve the peelability between these layers. That is, at least the surface of the release layer to be adhered to the metal film layer may be formed of a water-soluble resin. For example, the release layer may be formed of only the water-soluble resin release layer, or the surface to be adhered to the metal film layer may be formed of a water- Layer structure of a release layer (a release layer disposed on the metal film layer side) and another release layer (release layer disposed on the plastic film layer side) different from the release layer formed of a water-soluble resin. By adopting a release layer in which at least the surface to be bonded to the metal film is formed of a water-soluble resin, the support can be peeled off between the support layer and release layer after curing of the curable resin composition as a support, Since the layer is easily removed by an aqueous solution, it becomes possible to form a metal film layer having excellent uniformity on the adherend. The separation of the support between the support layer and the release mold layer is carried out at the interface between the support and the release mold layer when the release mold layer is formed solely of water-soluble resin, and the mold release layer is composed of a release layer formed of a water- In the case of two layers of another release layer formed of a fluororesin, it is carried out at the interface between the other release layer and the water-soluble resin release layer. As the releasing agent of the alkyd resin, AL-5 (manufactured by Lintec Corporation) can be mentioned.

The upper limit of the layer thickness of the release layer is preferably 20 占 퐉 from the viewpoint of preventing cracks from occurring in the metal film layer due to the difference in thermal expansion coefficient between the metal film layer and the release layer in the case of thermally curing the curable resin composition layer, More preferably 10 mu m, further more preferably 3 mu m, further preferably 2 mu m, and particularly preferably 1 mu m. On the other hand, the lower limit of the layer thickness of the release layer is preferably 0.01 탆, more preferably 0.02 탆, and even more preferably 0.03 탆 from the viewpoint of preventing deterioration of the releasability of the support layer. Here, the " layer thickness " is the thickness of a single-layered release layer, and the total thickness of multiple layers in a multi-layered form. For example, in the case where the release layer is composed of the water-soluble resin release layer and other release layers such as a silicone resin, an alkyd resin, and a fluororesin, the total thickness of these release layers is set in the above range .

(Water-soluble cellulose resin)

The " water-soluble cellulose resin " in the present invention means a cellulose derivative subjected to treatment for imparting water-solubility to cellulose, and cellulose ether and cellulose ether ester are suitably used.

The cellulose ether is an ether formed by the conversion of one or more hydroxyl groups present in one or more anhydroglucose repeating units of the cellulose polymer to impart one or more ether linkages to the cellulose polymer, An alkyl group (having 1 to 4 carbon atoms) which may be substituted with at least one substituent selected from a hydroxyl group, a carboxyl group, an alkoxy group (having 1 to 4 carbon atoms) and a hydroxyalkoxy group (having 1 to 4 carbon atoms) . Specific examples include hydroxyalkyl groups (having 1 to 4 carbon atoms) such as 2-hydroxyethyl, 2-hydroxypropyl, 3-hydroxypropyl and the like; Alkoxy (having 1 to 4 carbon atoms) alkyl group (having 1 to 4 carbon atoms) such as 2-methoxyethyl, 3-methoxypropyl, 2-methoxypropyl and 2-ethoxyethyl; (1 to 4 carbon atoms) such as 2- (2-hydroxyethoxy) ethyl or 2- (2-hydroxypropoxy) propyl, a carboxyalkyl group such as carboxymethyl 1 to 4), and the like. The ether linking group in the polymer molecule may be a single species or a plurality of species. That is, cellulose ether having only one kind of ether linking group or cellulose ether having plural kinds of ether linking groups may be used.

Specific examples of the cellulose ether include cellulose derivatives such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, hydroxybutyl methyl cellulose, hydroxyethyl ethyl cellulose, carboxymethyl cellulose and water-soluble salts thereof For example, an alkali metal salt such as sodium salt).

The average number of moles of the ether groups substituted per unit glucose ring in the cellulose ether is not particularly limited, but is preferably 1 to 6. The weight average molecular weight of the cellulose ether is preferably 20,000 to 60,000.

On the other hand, a cellulose ether ester refers to an ester which is formed between at least one hydroxyl group present in cellulose and at least one organic acid or a reactive derivative thereof, thereby forming an ester linkage in the cellulose ether. Herein, the term " cellulose ether " is as defined above. &Quot; Organic acid " includes an aliphatic or aromatic carboxylic acid (having 2 to 8 carbon atoms), the aliphatic carboxylic acid may be acyclic (branched or unbranched) It may be saturated or unsaturated. Specific examples of the aliphatic carboxylic acid include substituted or unsubstituted alicyclic dicarboxylic acids such as acetic acid, propionic acid, butyric acid, valeric acid, malonic acid, succinic acid, glutaric acid, fumaric acid and maleic acid; Non-cyclic hydroxy-substituted carboxylic acids such as glycolic acid or lactic acid; Acyclic aliphatic hydroxy-substituted di- or tri-carboxylic acids such as maleic acid, tartaric acid and citric acid. The aromatic carboxylic acid is preferably an aryl carboxylic acid having 14 or less carbon atoms, and an aryl carboxylic acid containing an aryl group such as a phenyl or naphthyl group having at least one carboxyl group (for example, 1, 2 or 3 carboxyl groups) desirable. The aryl group may also be substituted by one or more (e.g., 1, 2 or 3) groups selected from hydroxy, alkoxy of 1 to 4 carbon atoms (e.g., methoxy) and sulfonyl, May be substituted. Suitable examples of arylcarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid (1,2,4-benzenetricarboxylic acid) and the like.

When the organic acid has more than one carboxyl group, suitably only one carboxyl group of the acid forms an ester linkage to the cellulose ether. For example, in the case of hydroxypropylmethylcellulose succinate, one carboxyl group of each succinate group forms an ester linkage with the cellulose, and the other carboxy group is present as a free acid. An " ester linkage " is formed by reaction with cellulose or cellulose ether and a suitable organic acid or reactive derivative thereof as described above. Suitable reactive derivatives include, for example, acid anhydrides such as phthalic anhydride.

The ester linking group in the polymer molecule may be a single species or a plurality of species. That is, cellulose ether ester having only one kind of ester linking group or cellulose ether ester having plural kinds of ester linking groups may be used. For example, hydroxypropylmethylcellulose acetate succinate is a mixed ester of hydroxypropyl methylcellulose having both a succinate group and an acetate group.

Suitable cellulose ether esters are esters of hydroxypropylmethylcellulose or hydroxypropylcellulose, and specifically include hydroxypropylmethylcellulose acetate, hydroxypropylmethylcellulose succinate, hydroxypropylmethylcellulose acetate succinate, hydroxypropylmethylcellulose acetate succinate, Methyl cellulose phthalate, hydroxypropylmethyl cellulose trimellitate, hydroxypropylmethyl cellulose acetate phthalate, hydroxypropylmethyl cellulose acetate trimellitate, hydroxypropylcellulose acetate phthalate, hydroxypropylcellulose butylate phthalate, hydroxypropylcellulose Acetate phthalate succinate and hydroxypropylcellulose acetate trimellitate succinate. Number, and these may be used alone or in combination of two or more.

Among these, hydroxypropylmethylcellulose phthalate, hydroxypropylmethylcellulose acetate succinate, and hydroxypropylmethylcellulose acetate phthalate are preferable.

The average number of moles of ester groups substituted per unit glucose in the cellulose ether ester is not particularly limited, but is preferably 0.5 to 2, for example. The weight average molecular weight of the cellulose ether ester is preferably 20,000 to 60,000.

The production method of cellulose ether and cellulose ether ester is known and can be obtained by reacting an etherifying agent and an esterifying agent in accordance with a regular method using natural cellulose (pulp) as a raw material. In the present invention, It is also good. For example, HP-55 and HP-50 (manufactured by Shin-Etsu Chemical Co., Ltd.) (together with hydroxypropylmethyl cellulose phthalate).

(Water-soluble polyester resin)

The " water-soluble polyester resin " used in the present invention means a substantially linear polymer such as a polyester resin, which is synthesized by a conventional polycondensation reaction using a polyvalent carboxylic acid or an ester-forming derivative thereof and a polyhydric alcohol or an ester- , And a hydrophilic group is introduced into the molecule or at the end of the molecule. Examples of the hydrophilic group include an organic acid group such as a sulfo group, a carboxyl group, and a phosphoric acid group, or a salt thereof, and preferably a sulfonic acid group or a salt thereof, a carboxylic acid group or a salt thereof. The water-soluble polyester resin is preferably a sulfo group or a salt thereof and / or a carboxyl group or a salt thereof.

Typical examples of the polyvalent carboxylic acid component of the polyester resin include terephthalic acid, isophthalic acid, phthalic acid, phthalic anhydride, 2,6-naphthalenedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and adipic acid. Or a combination of two or more species. In addition to the various compounds, unsaturated carboxylic acids such as hydroxycarboxylic acids such as p-hydroxybenzoic acid, maleic acid, fumaric acid, itaconic acid and the like may also be used in combination with small amounts.

Representative examples of the polyhydric alcohol component of the polyester resin include ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,6-hexane glycol, 1,4- Glycol, dimethylol propionic acid, glycerin, trimethylol propane or poly (tetramethylene oxide) glycol, etc. These may be used alone or in combination of two or more.

The introduction of the hydrophilic group in the molecule or at the molecular end of the polyester resin may be carried out by a publicly known method, but it is also possible to copolymerize an ester-forming compound containing a hydrophilic group (for example, an aromatic carboxylic acid compound or a hydroxy compound) Shape is preferable.

For example, when a sulfonic acid base is introduced, there may be mentioned sodium 5-sulfonic acid isophthalic acid, ammonium 5-sulfonic acid isophthalic acid, sodium 4-sulfonic acid isophthalic acid, ammonium 4-methylsulfonic acid isophthalic acid, Terephthalic acid, potassium 5-sulfonate isophthalate, potassium 4-sulfonate isophthalate, potassium 2-sulfonate terephthalate and the like.

When a carbonic acid group is introduced, it is possible to use, for example, 1 or 2 selected from trimellitic anhydride, trimellitic acid, pyromellitic anhydride, pyromellitic acid, trimesic acid, cyclobutanetetracarboxylic acid, It is preferable to copolymerize two or more kinds thereof. After the copolymerization reaction, the carboxylic acid base group can be introduced into the molecule by neutralization with an amino compound, ammonia, an alkali metal salt or the like.

The molecular weight of the water-soluble polyester resin is not particularly limited, but a weight average molecular weight of 10000 to 40000 is preferable. When the weight average molecular weight is less than 10,000, the layer formability tends to decrease. When the weight average molecular weight exceeds 40000, the solubility tends to decrease.

In the present invention, commercially available products can be used as the water-soluble polyester resin. Examples thereof include "Pluscoat Z-561" (weight average molecular weight: about 27,000), "Pluscoat Z-565" ) (Manufactured by Goo Chemical Co., Ltd.).

(Water-soluble acrylic resin)

The "water-soluble acrylic resin" in the present invention is an acrylic resin dispersed or dissolved in water by containing a carboxyl group-containing monomer as an essential component.

The acrylic resin is more preferably a monomer component in which a carboxyl group-containing monomer and a (meth) acrylic acid ester are essential, and if necessary, an acrylic polymer containing other unsaturated monomer as a monomer component.

Examples of the monomer containing a carboxyl group in the monomer component include (meth) acrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid, maleic anhydride, monomethyl maleate, monobutyl maleate, And monobutyl itaconate. One or two or more of them may be used. Among them, (meth) acrylic acid is suitable.

Examples of the (meth) acrylic esters include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (Meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (Meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate and stearyl (meth) acrylate. One or more of these alkyl esters can be used .

Examples of other unsaturated monomers include aromatic alkenyl compounds, vinyl cyanide compounds, conjugated diene compounds, halogen-containing unsaturated compounds, and hydroxyl group-containing monomers. Examples of the aromatic alkenyl compound include styrene,? -Methylstyrene, p-methylstyrene, p-methoxystyrene and the like. Examples of the vinyl cyanide compound include acrylonitrile, methacrylonitrile and the like. Examples of the conjugated diene compound include butadiene, isoprene, and the like. Examples of the halogen-containing unsaturated compound include vinyl chloride, vinylidene chloride, perfluoroethylene, perfluoropropylene, vinylidene fluoride, and the like. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, ) Acrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, and? -Hydroxymethylethyl (meth) acrylate. These may be used alone or in combination of two or more.

As described later, in the present invention, the releasing layer is preferably formed by a method of applying a coating liquid (coating liquid) containing a material constituting the releasing layer to a support layer and drying the coating. When a water-soluble acrylic resin is used, the coating liquid may be in the form of an emulsion or an aqueous solution.

When a water-soluble acrylic resin is used in the form of an emulsion, a core-shell type emulsion is suitable. In the core-shell type emulsion, it is important that a carboxyl group is present in the cell of the core shell particle. And an acrylic resin.

For example, Jongkuril 7600 (Tg: about 35 占 폚), 7630A (Tg: about 53 占 폚), 538 J (Tg: about 66 占 폚), and the like can be used as a dispersion (emulsion) 352D (Tg: about 56 占 폚) (manufactured by BASF Japan Ltd.).

When the water-soluble acrylic resin is used in the form of an aqueous solution, the acrylic resin is an acrylic resin containing a carboxyl group-containing monomer and a (meth) acrylic acid ester, and it is important that the acrylic resin is of relatively low molecular weight. Therefore, it is preferable that the weight average molecular weight is 1000 to 50000, and when the weight average molecular weight is less than 1000, the layer formability tends to decrease. When the weight average molecular weight exceeds 50000, the adhesion with the support layer becomes higher, The releasability of the support layer tends to be lowered.

A commercially available aqueous solution of such a water-soluble acrylic resin can be used, for example, Joncryl 354J (manufactured by BASF Japan Ltd.).

In the emulsion of water-soluble acrylic resin and the aqueous solution, the emulsion side is liable to be thinned because of its high molecular weight. Therefore, an emulsion of a water-soluble acrylic resin is suitable.

(Metal compound, carbon powder, metal powder, black dye)

Known components such as carbon powder, metal compound powder, metal powder, and black dye, which are laser energy absorbing components contained in the water-soluble resin, can be used. In addition, any one of them or two or more of them may be used in combination. By incorporating these laser energy absorbing components in the water-soluble resin and irradiating laser light from above the water-soluble resin layer present on the metal film layer, the workability in blind via formation becomes good. The laser energy absorbing component may be contained in only one layer when the release layer formed of a water-soluble resin is composed of two or more layers.

Examples of the carbon powder include powders of carbon black such as furnace black, channel black, acetylene black, thermal black and anthracene black, graphite powder, or a mixture thereof. Examples of the metal compound include titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, zinc oxide such as manganese dioxide and zinc oxide, silicon dioxide, aluminum oxide, rare earth oxide, Cobalt oxide such as cobalt oxide, tin oxide such as tin oxide, tungsten oxide such as tungsten oxide, silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, rare earth oxides, And the like. Examples of the metal powder include powders of silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc, . Examples of the black dye include azo dyes (such as monoazo dyes and dyesazo dyes), azo-methine dyes, anthraquinone dyes, quinoline dyes, ketone imine dyes, fluorone dyes, nitro dyes, xanthene dyes, acenaphthene dyes, Examples of the dyes include dyes, thiophthalic acid dyes, thiophthalic acid dyes, thiophthalic acid dyes, thiophthalic acid dyes, thiophthalic acid dyes, thiophthalic acid dyes, . The black dye is preferably a solvent-soluble black dye in order to improve the dispersibility into the water-soluble resin. These laser energy absorbing components may be used alone or in a mixture of different kinds. The laser energy absorbing component is preferably a carbon powder from the viewpoint of conversion efficiency of laser energy into heat, versatility and the like, and carbon black is particularly preferable.

The blending amount of the laser energy absorbing component composed of at least one member selected from a metal compound component, a carbon powder component, a metal component, and a black colorant is preferably within a range from 0.01 to 10 parts by weight, based on all the components constituting the water-soluble resin layer Is 0.05 to 40% by mass, preferably 0.1 to 20% by mass, and more preferably 1 to 10% by mass. When the addition amount is small, improvement of the laser processability tends not to be sufficiently exhibited. If the addition amount is large, the film-forming property of the release layer is lowered, and preparation of the release layer tends to be difficult. The upper limit of the average particle diameter of the laser energy absorbing component is preferably 1 占 퐉 or less, more preferably 0.1 占 퐉 or less from the viewpoint of efficiently absorbing laser energy. On the other hand, the lower limit of the average particle diameter of the laser energy absorbing component is preferably 0.005 mu m, more preferably 0.01 mu m, from the viewpoint of dispersibility. Here, the " average particle diameter " can be measured by a particle size distribution measuring apparatus or a BET method. The BET method is a method of adsorbing an adsorbed occupied area on the surface of powder particles at a temperature of liquid nitrogen, and determining the specific surface area of the sample from the amount thereof. The average particle diameter was determined from the specific surface area obtained from the BET method.

The method of forming the releasing layer is not particularly limited and a known lamination method such as hot press, heat roll laminate, extrusion laminate, application and drying of the coating solution can be adopted, but a layer having a high uniformity It is preferable to coat and dry the coating liquid containing the material used for the release layer in view of easy formation and the like. For example, a resin varnish in which a resin component (water-soluble resin or the like) constituting the release layer is dissolved or dispersed in an organic solvent and a laser energy absorbing component is dispersed is prepared, and the resin varnish is applied to a bar- ) Or the like on a plastic film layer and drying the organic solvent by heating or hot air blowing to form a release layer. The organic solvent for preparing the coating solution is not particularly limited and examples thereof include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate , And the like; aromatic hydrocarbons such as toluene and xylene; dimethylformamide; dimethylacetamide; and N-methylpyrrolidone. The organic solvent may be used alone or in combination of two or more.

≪ Metal film layer &

Examples of the metal used for the metal film layer include metals such as gold, platinum, silver, copper, aluminum, cobalt, chromium, nickel, titanium, tungsten, zinc, iron, tin and indium, Nickel, titanium, nickel-chromium alloy, aluminum, zinc, copper-nickel alloy, copper-titanium alloy (alloy) , Gold, silver and copper are preferable, and chromium, nickel, titanium, nickel-chromium alloy, aluminum, zinc, gold, silver and copper are more preferable, and copper is particularly preferable. The metal film layer may be a single layer or a multi-layer structure in which two or more different metals are laminated. For example, in a system in which heat deterioration (decomposition) or the like of the resin is likely to be caused by diffusion of the copper layer into the curable resin composition layer during thermal curing of the curable resin composition layer, A chromium layer, a nickel-chromium alloy layer, or a titanium layer may further be provided on the copper layer.

The thickness of the metal film layer is not particularly limited, but is 50 nm to 5000 nm, preferably 50 nm to 3000 nm, more preferably 100 nm to 3000 nm, and particularly preferably 100 nm to 1000 nm. When the layer thickness is too small, there is a tendency that the metal film tends to be cracked after the production of the metal film deposition film. In addition, in the desmear process or the like in the production of the multilayer printed circuit board, The surface of the insulating layer may be roughened. On the other hand, when the layer thickness is excessively large, it takes a long time to form a metal film, which is not preferable from the viewpoint of cost. In the case of the two-layer structure of the copper layer / chromium layer, nickel-chromium alloy layer or titanium layer as described above, the total layer thickness is the same as described above, and the thickness of the chromium layer, the nickel / chromium alloy layer or the titanium layer Is preferably 5 nm to 100 nm, more preferably 5 nm to 50 nm, particularly preferably 5 nm to 30 nm, and most preferably 5 nm to 20 nm.

<Curable resin composition layer>

The adhesive film for attaching a metal film in the present invention has a structure in which a curable resin composition layer is formed on a metal film layer of the above-mentioned adhesive film with a metal film. That is, the adhesive film with a metal film in the present invention has a cured resin composition layer in addition to a support layer and a metal film layer. It is also preferable to have a release layer between the support layer and the metal film layer like the metal film adhesion film. In the adhesive film with a metal film, the curable resin composition for use in the curable resin composition layer can be used without particular limitation, provided that the cured product thereof has sufficient hardness and insulating properties. Examples thereof include epoxy resins, cyanate ester resins , A composition containing at least a curing agent in a curable resin such as a phenol resin, a bismaleimide-triazine resin, a polyimide resin, an acrylic resin or a vinyl benzyl resin is used. As the curable resin, a composition containing an epoxy resin is preferable, and for example, a composition containing at least (a) an epoxy resin, (b) a thermoplastic resin and (c) a curing agent is preferable.

(a) Examples of the epoxy resin include, for example, bisphenol A type epoxy resin, biphenyl type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus containing epoxy resin, bisphenol S type epoxy resin, Cresol novolak type epoxy resin, bisphenol A novolak type epoxy resin, epoxy resin having a butadiene structure, diglycidyl ether of bisphenol, naphthalene diol Diglycidyl ether compounds, diglycidyl ether compounds, glycidyl ether compounds of phenols, and diglycidyl ether compounds of alcohols, and alkyl substituents, halides and hydrogenated products of these epoxy resins. Any of these epoxy resins may be used, or two or more epoxy resins may be mixed and used.

Among these epoxy resins, bisphenol A type epoxy resins, naphthol type epoxy resins, naphthalene type epoxy resins, biphenyl type epoxy resins, and epoxy resins having a butadiene structure are preferable from the viewpoints of heat resistance, insulation reliability and adhesion to a metal film Do. Specific examples of the epoxy resin include liquid bisphenol A type epoxy resin ("Epikote 828EL"; Japan Epoxy Resins Co., Ltd.), naphthalene type bifunctional epoxy resin ("HP4032", "HP4032D" ("HP4700" manufactured by DIC Corporation), naphthol type epoxy resin ("ESN-475V" manufactured by Tohto Kasei Co., Ltd.) and an epoxy resin having a butadiene structure Nippon Kayaku Co., Ltd .; &quot; YX4000 &quot;, manufactured by Japan Epoxy Resins Co., Ltd.), manufactured by Daicel Chemical Industries, Ltd.), epoxy resin having a biphenyl structure (NC3000H, NC3000L; Co., Ltd.).

(b) The thermoplastic resin is blended for the purpose of imparting appropriate flexibility to the composition after curing, and includes, for example, phenoxy resin, polyvinyl acetal resin, polyimide, polyamideimide, polyether sulfone, polysulfone And the like. Any one of them may be used alone, or two or more of them may be used in combination. The thermoplastic resin is preferably blended in a proportion of 0.5 to 60 mass%, more preferably 3 to 50 mass%, based on 100 mass% of the nonvolatile component of the curable resin composition. When the blend ratio of the thermoplastic resin is less than 0.5% by mass, it is difficult to form a uniform curable resin composition layer because the resin composition viscosity is low, and when it exceeds 60% by mass, the viscosity of the resin composition becomes excessively high , It tends to be difficult to fill the wiring pattern on the substrate.

Specific examples of the phenoxy resin include FX280 and FX293 (manufactured by Tohto Kasei Co., Ltd.), YX8100, YL6954 and YL6974 (manufactured by Japan Epoxy Resins Co., Ltd.) and the like.

The polyvinyl acetal resin is preferably a polyvinyl butyral resin, and specific examples of the polyvinyl acetal resin include Denki Kagaku Kogyo Kabushiki Kaisha (manufactured by Denki Kagaku Kogyo Kabushiki Kaisha ), S-LEC BH series, BX series, KS series, BL series, BM series (manufactured by Sekisui Chemical Co., Ltd.).

Specific examples of the polyimide include polyimide &quot; Rika coat SN20 &quot; and &quot; Rika coat PN20 &quot; (manufactured by New Japan Chemical Co., Ltd.). Further, a linear polyimide obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (Japanese Patent Application Laid-Open No. 2006-37083), a polysiloxane skeleton-containing polyimide JP-A-2002-12667, JP-A-2000-319386, etc.).

Specific examples of the polyamideimide include polyamideimide &quot; Viromax HR11NN &quot; and &quot; Viromax HR16NN &quot; (manufactured by Toyobo Co., Ltd.). Further, a modified polyamideimide such as polysiloxane skeleton-containing polyamideimide "KS9100", "KS9300" (manufactured by Hitachi Chemical Co., Ltd.) can be mentioned.

Specific examples of polyethersulfone include polyethersulfone &quot; PES5003P &quot; (manufactured by Sumitomo Chemical Co., Ltd.) and the like.

Specific examples of the polysulfone include polysulfone "P1700" and "P3500" (manufactured by Solvay Advanced Polymers).

(c) As the curing agent, for example, an amine curing agent, a guanidine curing agent, an imidazole curing agent, a phenol curing agent, a naphthol curing agent, an acid anhydride curing agent or an epoxy adduct or microencapsulated thereof, And the like. Among these, a phenol-based curing agent and a naphthol-based curing agent are preferable. In the present invention, the curing agent may be used alone or in combination of two or more.

MEH-7810, MEH-7851 (manufactured by Meiwa Plastic Industries, Ltd.), NHN, CBN, GPH (manufactured by Nippon Kayaku Co., Ltd .; (Manufactured by Tohto Kasei Co., Ltd.), LA7052, LA7054, LA3018, LA1356 (manufactured by DIC Corporation), and the like.

the mixing ratio of the epoxy resin (a) and the curing agent (c) is preferably such that the phenolic hydroxyl group equivalent of these curing agents is 0.4 to 2.0 in the case of the phenol-based curing agent or the naphthol-based curing agent, , And more preferably from 0.5 to 1.0. If the equivalent ratio of the reactor is outside this range, the mechanical strength and water resistance of the cured product tend to be lowered.

Further, the curable resin composition may further contain a curing accelerator (d) in addition to the curing agent (c). Examples of such curing accelerators include imidazole compounds and organic phosphine compounds. Specific examples thereof include 2-methylimidazole, triphenylphosphine, and the like. When (d) a curing accelerator is used, it is preferably used in an amount of 0.1 to 3.0% by mass based on the epoxy resin.

Further, the curable resin composition may contain (e) an inorganic filler for low thermal expansion of the cured composition. Examples of the inorganic filler include silica, alumina, mica, mica, silicate, barium sulfate, magnesium hydroxide and titanium oxide. Silica and alumina are preferable, and silica is particularly preferable. From the viewpoint of insulation reliability, the inorganic filler preferably has an average particle diameter of 3 mu m or less, more preferably 1.5 mu m or less. The content of the inorganic filler in the curable resin composition is preferably 20 to 60 mass%, more preferably 20 to 50 mass%, based on 100 mass% of the non-volatile component of the curable resin composition. When the content of the inorganic filler is less than 20 mass%, the effect of lowering the thermal expansion rate tends not to be sufficiently exhibited. When the content of the inorganic filler exceeds 60 mass%, the mechanical strength of the cured product tends to decrease .

The curable resin composition may contain other components as required. Examples of the other components include flame retardants such as organophosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants and metal hydroxides, fillers such as silicone powders, nylon powders and fluorine powders, thickeners such as orthobenzenes, , A fluorine-based or high-molecular antifoaming agent or leveling agent, an adhesion-imparting agent such as an imidazole-based, thiazole-based, triazole-based or silane-based coupling agent, a colorant such as phthalocyanine blue, phthalocyanine green, iodine green, disazo yellow or carbon black And the like.

The curable resin composition layer may be a prepreg impregnated with the above-mentioned curable resin composition in a sheet-like reinforcing base made of fibers. As the fiber of the sheet-like reinforcing base material, for example, those commonly used as prepreg fibers such as glass cloth and aramid fiber can be used. The prepreg can be formed by impregnating the curable resin composition with a sheet-like reinforcing base material hot-melt method or a solvent method, and semi-curing it by heating. The hot-melt method is a method in which a resin composition is temporarily coated on a coated paper having good releasability from a resin composition and the resin composition is laminated on a sheet-like reinforcing base material without dissolving the resin composition in an organic solvent, Or by direct coating (coating), for example. The solvent method is a method in which the sheet-like reinforcing base material is immersed in a varnish obtained by dissolving the resin composition in an organic solvent, the varnish is impregnated in the sheet-like reinforcing base material, and then dried.

The thickness of the curable resin composition layer varies depending on the thickness of the inner layer circuit conductor layer and the like, but is preferably 10 to 150 占 퐉, more preferably 15 to 80 占 퐉, from the viewpoint of insulation reliability between layers and the like.

The method of forming the release layer by a water-soluble resin containing a laser energy-absorbing component is not particularly limited, and a known lamination method such as hot press, heat roll laminate, extrusion laminate, coating and drying of a coating solution can be employed , A method of coating and drying a coating liquid containing a material used for the release layer is preferable in that it is easy to form a layer having high uniformity of property and the like. For example, a resin varnish is prepared by dissolving a water-soluble resin in an organic solvent and dissolving or dispersing the laser energy-absorbing component. The resin varnish is coated on a support using a bar coater or the like, Or drying the organic solvent by hot air blowing or the like to form a release layer. The organic solvent for preparing the coating solution is not particularly limited and examples thereof include ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate , And the like; aromatic hydrocarbons such as toluene and xylene; dimethylformamide; dimethylacetamide; and N-methylpyrrolidone. Two or more kinds of organic solvents may be used in combination.

When the release layer is formed by the resin varnish dispersed in the water-soluble resin in the laser energy absorbing component, the average particle diameter of the component is preferably 0.005 to 1 mu m, more preferably 0.01 to 0.1 mu m.

The metal film is preferably formed by at least one method selected from a vapor deposition method, a sputtering method and an ion plating method, and is preferably formed by a vapor deposition method and / or a sputtering method. These methods may be used in combination, but usually either method is used alone.

A sputtering method or a known method can be used. For example, a support having a release layer is placed in a vacuum container, an inert gas such as argon is introduced, and a DC voltage is applied to ionize the inert gas to collide against the target metal So that the film can be formed on the release layer by the metal which is punched out.

A known method can be used for the vapor deposition (vacuum vapor deposition). For example, a support having a release layer is placed in a vacuum container, and the metal is heated and evaporated to form a film on the release layer.

The ion plating method and a known method can be used. For example, a support having a release layer is placed in a vacuum container, the metal is heated and evaporated in a glow discharge atmosphere to form a film on the release layer by the ionized evaporation metal Can be performed.

The metal film adhering film can be produced by forming a curable resin composition layer on the surface of the metal film layer after the step of forming the metal film layer of the metal film attachment film. For example, a resin varnish obtained by dissolving a resin composition in an organic solvent is prepared, and this resin varnish is applied onto a metal film-attached film using a die coater or the like. And then drying the organic solvent by heating or hot air blowing to form a resin composition layer.

Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve, butyl Carbitol such as carbitol, aromatic hydrocarbons such as toluene and xylene, dimethylformamide, dimethylacetamide and N-methylpyrrolidone. Two or more kinds of organic solvents may be used in combination.

The drying conditions are not particularly limited, but the drying is performed so that the content of the organic solvent in the resin composition layer is 10 mass% or less, preferably 5 mass% or less. The resin composition layer is formed by drying the varnish containing, for example, 30 to 60 mass% of the organic solvent at 50 to 150 캜 for 3 to 10 minutes, depending on the amount of the organic solvent in the varnish and the boiling point of the organic solvent.

In addition, unlike the metal film-attached film, the adhesive film for attaching a metal film is produced by forming an adhesive film on which a curable resin composition layer is formed on a support as described above, To be brought into contact with each other under a heating condition. When the curable resin composition layer is a prepreg, the prepreg can be laminated on the support layer, for example, by vacuum lamination. The adhesive film can be produced by a known method. The support layer and the curable resin composition layer of the adhesive film are as described above.

The bonding of the metal film-attached film and the adhesive film or the prepreg is performed by overlapping the metal film-attached film and the adhesive film or the prepreg so that the metal film layer of the metal film-attached film and the adhesive film or the curable resin composition layer of the prepreg face each other, , Heat rolls or the like. The heating temperature is preferably 60 to 140 占 폚, more preferably 80 to 120 占 폚. The compression pressure is preferably 1 to 11 kgf / cm 2 (9.8 × 10 ⁴ to 107.9 × 10 ⁴ N / m 2), and particularly preferably 2 to 7 kgf / cm 2 (19.6 × 10 ⁴ to 68.6 × 10 ⁴ N / m 2).

[Fabrication of circuit board]

A method of manufacturing a circuit board using the metal film-attached film or the metal film-attached adhesive film of the present invention will be described. First, a lamination step of laminating a metal film-attaching film or a metal film-attaching adhesive film on an inner-layer circuit board is performed. When a film with a metal film is used, the metal film layer is overlaid so as to be in contact with the surface of the curable resin composition layer existing between the inner-layer circuit substrates. When an adhesive film with a metal film is used, the curable resin composition layer is laminated on the inner-layer circuit board as an adhesive surface.

The curable resin composition layer on the inner layer circuit board can be formed by a known method. For example, an adhesive film on which the curable resin composition layer is formed on the above-mentioned support layer is laminated on the inner layer circuit board, And then removed by peeling or the like, whereby the curable resin composition layer can be formed on the inner-layer circuit board. The laminating conditions of the adhesive film are the same as the laminating conditions such as an adhesive film with a metal film to be described later.

In the present invention, in the case of producing a circuit board by using a prepreg, a single prepreg or a multilayer prepreg in which a plurality of prepregs are stacked to form a multilayer prepreg is laminated on an inner-layer circuit board, It is possible to laminate the metal film attached film so that the metal film layer overlaps the surface of the prepreg. Similarly, a metal film-attached film is laminated on one surface or both surfaces of a multilayer prepreg in which a single prepreg or a plurality of prepregs are stacked so as to be in contact with the surface of the prepreg, The prepreg can be cured to produce a metal-clad laminate.

The lamination of the metal film-adhering film and the metal film-attaching film laminate the film on the surface of the object to be processed by roll, press compression or the like in view of workability and the same contact state being easily obtained. Among them, it is preferable to laminate under reduced pressure by the vacuum laminating method. The laminating method may be a batch method or a continuous method using a roll.

Lamination is generally performed under a reduced pressure of 20 mmHg (26.7 hPa) or less and a pressure of 1 to 11 kgf / cm 2 (9.8 × 10 ⁴ to 107.9 × 10 ⁴ N / m 2) Do.

Vacuum laminates can be carried out using commercially available vacuum laminators. As a commercially available vacuum laminator, a vacuum type vacuum laminator MVLP-500 (manufacturer: Meiki Co., Ltd.), a varnish applicator (Nichigo-Morton Co., Ltd.), a roll type dry coater Industrials Ltd.) and a vacuum laminator (manufactured by Hitachi AIC Inc.). After the laminating step, the laminated film may be smoothed by a hot press with a metal plate, if necessary. The smoothing step can be carried out by heating and pressing the film with a metal plate such as a heated SUS hard plate at normal pressing (at atmospheric pressure). The heating and pressurizing conditions can be the same as those in the lamination process. The lamination step and the smoothing step can be continuously carried out by a commercially available vacuum laminator. As a commercially available vacuum laminator, for example, vacuum laminator (manufactured by Meiki Co., Ltd.) and varnish applicator (manufactured by Nichigo-Morton Co., Ltd.) can be mentioned.

Next, a step of curing the curable resin composition layer to form an insulating layer is performed. Curing is usually carried out by heat curing treatment. The curing conditions vary depending on the kind of the curable resin and the like, but generally the curing temperature is 120 to 200 占 폚 and the curing time is 15 to 90 minutes. In addition, it is preferable from the viewpoint of prevention of wrinkles on the surface of the insulating layer to be formed that it is cured stepwise from a relatively low curing temperature to a high curing temperature or hardened while being raised.

Then, a step of peeling the support layer is carried out. The support may be peeled manually or mechanically. As described above, the peeling is performed at the interface of the release layer formed of the water-soluble resin, and after the support layer is peeled, the release layer formed of the water-soluble resin remains on the metal film layer.

Next, a step of forming blind vias by laser irradiation is performed. The irradiation of the laser is performed from above the release layer formed of a water-soluble resin. Examples of the laser include a carbon dioxide gas laser, a YAG laser, and an excimer laser, but a carbon dioxide gas laser is particularly preferable from the viewpoint of processing speed and cost. A laser having a wavelength of 9.3 to 10.6 mu m is generally used for the carbon dioxide gas laser to be irradiated. Also, the number of shots is selected in a range of 1 to 5 shots depending on the depth and hole diameter of the blind via to be formed. From the viewpoint of increasing the processing speed of the blind via and improving the productivity of the circuit board, it is preferable that the number of the blades is small, and the number of the blades is preferably 3 shots or less. The energy of the carbonic acid gas laser is set to 0.5 mJ or more, preferably 1 mJ or more, and more preferably 2 mJ or more, depending on the number of shots, the depth of the blind via, the thickness of the metal film layer and the thickness of the release layer. On the other hand, if the energy of the carbon dioxide gas laser is excessively high, the ground conductor layer of the blind via tends to be damaged and the shape of the blind via tends to deteriorate. Therefore, the upper limit is preferably 20 mJ or less, more preferably 15 mJ or less , More preferably 10 mJ or less, and most preferably 5 mJ or less.

The top diameter of the blind via is preferably 100 占 퐉 or less, more preferably 90 占 퐉 or less, and more preferably 80 占 퐉 or less in order to cope with the thinning of the circuit board and the high density of the wiring Do.

Further, in the case of processing into a plurality of shots, since the processing heat is filled in the holes in the burst mode, which is a continuous shot, the workability of the inorganic filling material and the thermosetting resin composition tends to be different, It is preferable to use a cycle mode in which a plurality of shots having temporal intervals are provided.

Although the pulse width of the carbon dioxide gas laser is not particularly limited, if the pulse width is large, the metal film of the blind via opening protrudes and the shape around the via tends to deteriorate. More preferably 1 to 14 占 퐏.

Further, the energy of the carbon dioxide gas laser is the energy value of the laser at the surface of the insulating layer per shot, and is adjusted according to the output of the oscillator, the collimation lens (energy adjusting lens) . The mask diameter is actually chosen according to the diameter of the blind via to be machined. The energy value can be measured by disposing a measuring device (power sensor) on a pedestal for laser processing and measuring the energy at the surface height of the insulating layer of the circuit board to be processed. In addition, a commercially available carbon dioxide gas laser device is equipped with a measuring device, and energy on the surface to be irradiated can be easily measured. Examples of the commercially available carbon dioxide gas laser device include ML605GTWII manufactured by Mitsubishi Electric Corporation, LC-G series manufactured by Hitachi Via Mechanics, Ltd., a substrate drilling laser processing machine manufactured by Matsushita Welding Systems Co., .

After the step of forming the blind via, the support is peeled off if necessary, and the step of dissolving and removing the release layer of the water-soluble resin remaining on the metal film layer is carried out. The aqueous solution for dissolving and removing the release layer is preferably an alkaline aqueous solution obtained by dissolving sodium carbonate, sodium hydrogen chloride, sodium hydroxide, potassium hydroxide or the like in water at a concentration of 0.5 to 10% by weight. There are no particular limitations on the method of dissolution removal, and examples thereof include a method of dissolving and removing the inner layer circuit board in an aqueous solution after the support layer is peeled off, a method of spraying the aqueous solution in a spray or mist, have. The temperature of the aqueous solution is usually from room temperature to 80 ° C, and the treatment time is usually from 10 seconds to 10 minutes by an aqueous solution such as water immersion or spraying. Examples of the alkaline aqueous solution include alkali type alkaline developer solutions (for example, aqueous solutions of sodium carbonate at a concentration of 0.5 to 2% by weight, at 25 ° C to 40 ° C) for use in the production of circuit boards, (For example, an aqueous alkali solution containing sodium carbonate, sodium hydroxide or the like, at 60 to 80 ° C) used in the desmearing process, and the like It can also be used.

After the step of dissolving and removing the release layer, it is preferable to carry out the desmearing step. The dismear process is a process for removing the via-bottom residue mainly caused by the formation of the blind via, and may be carried out for the purpose of harmonizing the via wall surface. The desmearing step can be performed by a known method such as a dry method such as plasma or a wet method by an oxidizing agent treatment such as an alkaline permanganic acid solution. Particularly, the desmear by the oxidizing agent is preferable in that the smear of the via bottom is removed and the via wall surface is harmonized with the oxidizing agent to improve the plating adhesion strength. Further, in the present invention, since the surface of the insulating layer is not roughened, it is advantageous in forming a fine wiring and is also advantageous in shortening the circuit manufacturing process. The desmearing process by the oxidizing agent is usually carried out by swelling treatment with a swelling liquid, coarsening treatment with an oxidizing agent and neutralization treatment with a neutralizing liquid in this order. Examples of the swelling solution include an alkaline solution and a surfactant solution, and preferably an alkaline solution. Examples of the alkaline solution include a sodium hydroxide solution and a potassium hydroxide solution. When an alkali solution is used for the desmear treatment, the step of dissolving and removing the release layer and the desmearing step may be simultaneously carried out. Commercially available swelling solutions include, for example, Swelling Dip Securiganth P, Swelling Dip Securiganth SBU (manufactured by Atotech Japan K.K.) and the like. As the oxidizing agent, there may be mentioned, for example, an alkaline permanganic acid solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganic acid solution is carried out by treating the solution with an oxidizing agent heated to 60 to 80 캜 for 10 to 30 minutes. The concentration of the permanganate salt in the alkaline permanganic acid solution is generally from 5 to 10%. Commercially available oxidizing agents include, for example, alkaline permanganic acid solutions such as Concentrate Compact CP (manufactured by Atotech Japan K.K.) and Dozing SolutionSecurity Gun P, and the like. As the neutralization solution, an acidic aqueous solution is preferable, and a commercially available product is a reduction solution Securirigin P (neutralization solution) (manufactured by Atotech Japan K.K.).

The metal film layer is formed as a conductor layer, or the metal film layer is grown by plating (electroless plating and / or electrolytic plating) on the metal film layer to form a conductor layer (at this time, do). Generally, it is preferable to form a conductor layer on the metal film layer by electrolytic plating. The conductive layer formation by electrolytic plating can be carried out by a known method such as a semi-specific method. For example, a plating resist is formed on a metal film layer, and a conductive layer is formed by electrolytic plating. The electroplating layer is preferably copper, and its thickness depends on the design of the intended circuit board, but is generally from 3 to 35 mu m, preferably from 5 to 30 mu m. After the electrolytic plating, the plating resist is removed with a plating resist stripping solution such as an alkaline aqueous solution, and then the metal film layer is removed to form a wiring pattern. The removal of the metal film layer can be removed by etching with a solution which dissolves the metal forming the metal film layer. For example, if copper is used, an etching solution such as an aqueous solution of ferric chloride, an aqueous solution of sodium peroxodisulfate and sulfuric acid, CF-6000 (manufactured by Mec Co., Ltd.), E- An alkaline etching solution such as Process-WL (manufactured by Meltex Inc.) may be used. In the case of nickel, an etching solution containing nitric acid / sulfuric acid as a main component can be used. Examples of commercially available products include NH-1865 (manufactured by Mec Co., Ltd.) and Melstrip N-950 (manufactured by Meltex Inc.) .

A through hole forming process may be added as needed. The formation of the through hole is generally performed in the core substrate, but a through hole may be formed after the formation of the insulating layer. In this case, the same process as the dismage process can be applied to the through hole. A mechanical drill is generally used to form the through hole.

Example

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples. In the following description, &quot; part &quot; means &quot; part by mass &quot;.

(Example 1)

&Lt; Fabrication of metal film-attached film >

Hydroxypropylmethyl cellulose phthalate (&quot; HP-55 &quot;, manufactured by Mitsubishi Chemical Corporation) was added to a solvent in which methyl ethyl ketone (hereinafter abbreviated as MEK) and cyclohexanone were mixed at a ratio of 1: 1 : Shin-Etsu Chemical Co., Ltd.) was dissolved in a solid content of 10% by mass to obtain a hydroxypropylmethylcellulose phthalate solution. 11 parts of carbon black ("Printex V"; manufactured by Degussa Japan Co., Ltd., average particle diameter: about 25 nm) was uniformly dispersed in 100 parts of a hydroxypropyl methylcellulose phthalate solution to prepare a mold release solution. The above releasing solution was coated on a polyethylene terephthalate film (hereinafter may be abbreviated as &quot; PET &quot;) film having a thickness of 38 탆 by a bar coater and heated from room temperature to 140 캜 using a hot- The solvent was removed by raising the temperature to 80 ° C, and a water-soluble resin layer (release layer) having a thickness of about 2 μm was formed on the PET film. Then, a copper layer having a thickness of about 1000 nm was formed on the release layer by vapor deposition to produce a metal film-attached film.

&Lt; Preparation of an adhesive film having a curable resin composition layer >

28 parts of liquid bisphenol A type epoxy resin (epoxy equivalent 180, "Epicoat 828EL"; Japan Epoxy Resins Co., Ltd.) and 28 parts of naphthalene type tetrafunctional epoxy resin (epoxy equivalents 163, "HP4700" And 20 parts of a phenoxy resin ("YX6954BH30"; Japan Epoxy Resins Co., Ltd.) were dissolved by heating in a mixed solvent of 15 parts of MEK and 15 parts of cyclohexanone with stirring. 27 parts of a triazine-containing phenol novolak resin (hydroxyl group equivalent 125, "LA7054" manufactured by DIC Corporation), 27 parts of a naphthol curing agent (hydroxyl group equivalent 215, "SN-485" manufactured by Tohto Kasei Co 27 parts of a MEK solution having a solid content of 50% by mass of a curing catalyst ("2E4MZ" manufactured by Shikoku Chemicals Corporation), 0.1 part of spherical silica (average particle diameter 0.5 μm, "SOC2" Admatechs Company Limited), 15 parts by mass of a solid content of 15 parts by mass of a solid content of polyvinyl butyral resin ("KS-1" manufactured by Sekisui Chemical Co., Ltd.) dissolved in a mixed solvent of ethanol and water (mass ratio = 1: Were mixed and uniformly dispersed in a high-speed rotary mixer to prepare a resin varnish. The varnish was applied on a polyethylene terephthalate film having an aliquot release agent (AL-5, manufactured by Lintec Corporation) having a thickness of 38 mu m by a die coater, and the solvent was removed using a hot air drying oven to obtain a curable resin composition layer Was prepared.

&Lt; Fabrication of adhesive film with metal film &

The adhesive film was bonded at 90 deg. C so as to contact the cured resin composition surface of the adhesive film and the metal film surface of the metal film adhering film, and wound up to obtain a metal film adhered film.

&Lt; Lamination and curing of adhesive film with metal film over inner layer circuit board >

The copper layer of the glass epoxy substrate on which the circuit was formed with a copper layer having a thickness of 18 탆 was subjected to a treatment by treatment with CZ8100 (surface treatment agent containing azole copper complex and organic acid; manufactured by Mec Co., Ltd.) . Next, the release PET of the adhesive film with a metal film was peeled off, and the curable resin composition layer was brought into contact with the copper circuit surface. Using a batch type vacuum pressure laminator MVLP-500 (manufactured by Meiki Co., Ltd.) , And laminated on both sides of the substrate. The lamination was performed under reduced pressure for 30 seconds and at a pressure of 13 hPa or lower. Thereafter, it was thermally cured at 180 캜 for 30 minutes to form an insulating layer.

&Lt; Formation of blind vias &

After formation of the insulating layer, PET was peeled off and blind vias were formed from the hydroxypropylmethyl cellulose phthalate layer present on the metal film layer using a laser processing machine (carbon dioxide gas laser: ML605GTWII-P manufactured by Mitsubishi Electric Corporation) . Conditions of the laser irradiation were a pulse width of 13,, an energy of 3 mJ, a shot number of one shot, and a mask diameter of 1.1 mm.

(Example 2)

A blind via was formed in the same manner as in Example 1 except that the blending amount of carbon black was one part.

(Example 3)

A blind via was formed in the same manner as in Example 1 except that the pulse width of the laser processing condition was 7 占 퐏.

(Example 4)

A blind via was formed in the same manner as in Example 1 except that the blending amount of carbon black was 1 part and the pulse width of the laser processing condition was 7 占 퐏.

(Example 5)

A blind via was formed in the same manner as in Example 1 except that the pulse width of the laser processing conditions was 4..

(Example 6)

A blind via was formed in the same manner as in Example 1 except that the blending amount of carbon black was 1 part and the pulse width of the laser processing condition was 4..

(Example 7)

A metal film-attaching film and an adhesive film were produced in the same manner as in Example 1. [

<Formation of Curable Resin Composition Layer on Circuit Board by Adhesive Film>

A copper layer of a glass epoxy substrate having a circuit formed on a copper layer having a thickness of 18 μm is treated with CZ8100 (a copper complex of an azole, a surface treatment agent containing an organic acid; manufactured by Mec Co., Ltd.) Respectively. The adhesive film was brought into contact with the surface of the copper circuit and laminated on both sides of the circuit board using a vacuum pressure laminator MVLP-500 (manufactured by Meiki Co., Ltd.) in a batch system. The laminate was decompressed for 30 seconds and the air pressure was 13 hPa or less. Then, after cooling to room temperature, the support layer of the adhesive film was peeled off, and a curable resin composition layer was formed on both sides of the circuit board.

&Lt; Transfer of metal film by metal film deposition film >

The metal film-attached film was laminated on a circuit board such that the metal film layer was in contact with the curable resin composition layer. The lamination was carried out by using a batch type vacuum pressure laminator MVLP-500 (manufactured by Meiki Co., Ltd.) on both sides of the circuit board. The laminate was subjected to pressure reduction for 30 seconds to set the air pressure to 13 hPa or less, and then to press for 30 seconds at a pressure of 7.54 kgf / cm2. Thereafter, the curable resin composition layer was cured at 150 캜 for 30 minutes and further at 180 캜 for 30 minutes to form an insulating layer (cured layer). The PET film was peeled off from the support layer of the metal film-adhering film with the insulating layer. The peelability was good and easily peeled off by hand.

(Comparative Example 1)

A perforation was made in the same manner as in Example 1 except that a release layer was formed from a solution of hydroxypropylmethylcellulose phthalate containing no carbon black.

(Comparative Example 2)

A release layer was formed from a hydroxypropylmethyl cellulose phthalate solution containing no carbon black, and perforations were carried out in the same manner as in Example 1 except that the pulse width of the laser processing conditions was 7 占 퐏.

(Comparative Example 3)

A PET film with a release layer adhered to a hydroxypropylmethylcellulose phthalate solution containing no carbon black was prepared and perforated in the same manner as in Example 1 except that the pulse width of the laser processing conditions was 4..

[Referential Example 1]

Using a thermoplastic fluororesin film (ETFE: ethylene-trifluoroethylene copolymer, &quot; Toyofron, &quot; manufactured by Toray Industries, Inc.) having a thickness of 50 占 퐉 as a support layer having a releasing function, A copper layer having a thickness of about 500 nm and a chromium layer having a thickness of about 20 nm were formed on the copper layer by sputtering (E-400S manufactured by Canon ANELVA Corporation), and a metal film layer having a total thickness of about 520 nm Respectively.

28 parts of liquid bisphenol A type epoxy resin (828 EL) and 28 parts of naphthalene type tetrafunctional epoxy resin (HP-4700) were dissolved by heating in a mixed solvent of 15 parts of MEK and 15 parts of cyclohexanone with stirring. 50 parts of a novolac resin (phenolic hydroxyl group equivalent 120, "LA7052" manufactured by DIC Corporation, solid content 60% by mass of MEK solution), phenoxy resin (molecular weight 50000, "E1256 , 20 parts of a curing catalyst (2E4MZ), 55 parts of spherical silica (SOC2), 20 parts of a polyvinyl butyral resin solution used in Example 1 , And 3 parts of an epoxy resin having a butadiene structure (molecular weight 27000; "PB-3600"; manufactured by Daicel Chemical Industries, Ltd.) were uniformly dispersed in a high-speed rotary mixer to prepare a resin varnish. The varnish was coated on a PET film having a thickness of 38 mu m by a die coater and the solvent was removed by using a hot air drying oven to produce an adhesive film having a thickness of 40 mu m as the curable resin composition layer.

In the same manner as in Example 1, the adhesive film was bonded to the metal film-attached film to form an adhesive film with a metal film, and the adhesive film with the metal film was laminated on the circuit board. Thereafter, the curable resin composition layer was cured at 150 캜 for 30 minutes and further at 180 캜 for 30 minutes to form an insulating layer (cured layer). When observed from above the transparent thermoplastic fluororesin film, the metal film layer contained many wrinkles. Further, the peelability of the thermoplastic fluororesin film layer was poor and the film was peeled off by hand, but some thermoplastic fluororesin films remained without being peeled off from the metal film and could not be completely peeled off.

[Reference Example 2]

(E-400S; manufactured by Canon Inc.) using a 20 占 퐉 -thick polyethylene terephthalate film (&quot; Finefil &quot;; Reiko Co., Ltd.) having a melamine- ANELVA Corporation), a copper layer having a thickness of about 500 nm, and a chromium layer having a thickness of about 20 nm were formed on the copper layer, and a metal film attached film having a total thickness of the metal film layer of about 520 nm was produced, , An adhesive film and a metal film attaching film were bonded to each other to prepare an adhesive film with a metal film, and the adhesive film with the metal film was laminated on the circuit board. Thereafter, the curable resin composition layer was cured at 150 캜 for 30 minutes and further at 180 캜 for 30 minutes to form an insulating layer (cured layer). No abnormality such as swelling between the resin and the metal film, wrinkles of the metal film, and cracks of the metal film were observed when the film was observed from above the transparent PET film. However, peeling of the PET film was difficult.

[Referential Example 3]

(E-400S manufactured by EI du Pont de Nemours & Co., Inc.) was applied to the acrylic releasing resin layer using a release PET film ("Cerafil HP2", manufactured by Toray Advanced Film Co., Ltd.) Manufactured by Canon ANELVA Corporation), a copper layer having a thickness of about 500 nm, and a chromium layer having a thickness of about 20 nm formed on the copper layer, and a total thickness of the metal film layer was about 520 nm, , An adhesive film and a metal film adhering film were bonded to each other to form an adhesive film with a metal film, and the adhesive film with the metal film was laminated on the circuit board. Thereafter, the curable resin composition layer was cured at 150 캜 for 30 minutes and further at 180 캜 for 30 minutes to form an insulating layer (cured layer). No abnormality such as swelling between the resin and the metal film, wrinkles of the metal film, and cracks of the metal film were observed when the film was observed from above the transparent PET film. However, peeling of the PET film was difficult. Further, the acrylic type releasable resin on the PET film was not dissolved in both water and an alkaline aqueous solution.

[Reference Example 4]

A solution of a solid content of 15 mass% dissolved in polyvinyl alcohol ("PTA-203"; manufactured by Kuraray Co., Ltd.) in a mixed solvent of ethanol and water (mass ratio = 1: 1) And the temperature was raised from room temperature to 140 ° C at a heating rate of 3 ° C / sec using a hot air drying furnace to remove the solvent, and a polyvinyl alcohol resin layer of about 1 μm was formed on the PET film. A copper layer having a thickness of about 500 nm and a chromium layer having a thickness of about 20 nm were formed on the polyvinyl alcohol resin layer by sputtering (E-400S, manufactured by Canon ANELVA Corporation) and the total thickness of the metal film layers was A metal film attachment film having a thickness of about 520 nm was produced.

30 parts of bisphenol A disiocyanate prepolymer (cyanate equivalent 232, &quot; BA30S75 &quot;, MEK solution of 75% solids; manufactured by Lonza Japan Ltd.), 30 parts of phenol novolak- type polyfunctional cyanate ester resin (cyanate equivalent 124, , 40 parts of a MEK solution having a solid content of 65% by mass of naphthol type epoxy resin (epoxy equivalent 340, "ESN-475V" manufactured by Tohto Kasei Co., Ltd.) 5 parts of a liquid bisphenol A type epoxy resin (828 EL), 5 parts of a phenoxy resin solution ("YP-70" manufactured by Tohto Kasei Co., Ltd.), a mixed solvent of MEK and cyclohexanone (weight ratio = 1: 15 parts of a solid solution (40% by mass of the solid used), 4 parts of cobalt (II) acetylacetonate (DMF solution of solid content 1% by mass; manufactured by Tokyo Chemical Industry Co., Ltd.) Were mixed and uniformly dispersed in a high-speed rotary mixer to prepare a resin varnish.

The resin varnish was coded on the metal film-attached film to produce an adhesive film with a metal film, and the adhesive film with the metal film was laminated on the circuit board. Thereafter, the curable resin composition layer was cured at 150 캜 for 30 minutes and further at 180 캜 for 30 minutes to form an insulating layer (cured layer). No abnormality such as swelling between the resin and the metal film, wrinkles of the metal film, and cracks of the metal film were observed when the film was observed from above the transparent PET film. However, peeling of the PET film was difficult.

(Measurement of laser processability)

The column diameter after laser processing was measured with a scanning electron microscope (type "SU-1500"; manufactured by Hitachi High-Technologies Corporation). The results are shown in Table 1.

As can be seen from the results of the examples and the reference example, the metal film layer having excellent uniformity over the insulating layer can be formed by the metal film-attached film and the metal film-attached adhesive film of the present invention. Further, as can be seen from Table 1, when the blind via is formed in the method of the present invention, since the release layer has the laser absorbing component, the diameter of the opening top becomes larger than that without the component, . In other words, since laser processing is possible under milder conditions, damage to the underlying metal layer and deterioration of the shape of the blind via can be suppressed.

The present application is based on Japanese Patent Application No. 2008-222731, the content of which is incorporated herein by reference in its entirety.

Claims (23)

A metal film-attached film having a support layer, a release layer formed on the support layer, and a metal film layer formed on the release layer, wherein at least the surface of the release layer that is in contact with the metal film layer is a water-soluble cellulose resin, And the water-soluble resin contains at least one selected from the group consisting of a metal compound powder, a carbon powder, a metal powder and a black dye, and the release layer is formed of at least one selected from the group consisting of a metal film layer side And a release layer formed of a silicone resin, an alkyd resin, or a fluororesin disposed on the support layer side, and a release layer formed of a water-soluble resin disposed on the support layer side. The water-soluble polyester resin according to claim 1, wherein the water-soluble polyester resin is a water-soluble polyester having at least one member selected from the group consisting of a sulfo group, a salt of a sulfo group, a carboxyl group and a salt of a carboxyl group, Wherein the water-soluble acrylic resin is a water-soluble acrylic resin. The metal film-attached film according to Claim 1 or 2, wherein the water-soluble resin contains at least one selected from the group consisting of metal compounds, carbon powder, metal powder and black dye in a proportion of 0.05 to 40 mass%. The metal film-attached film according to claim 1 or 2, wherein the support layer is a plastic film. The film with a metal film according to claim 1 or 2, wherein the support layer is a polyethylene terephthalate film. The metal film-attached film according to claim 1 or 2, wherein the metal film layer is formed by at least one method selected from a vapor deposition method, a sputtering method and an ion plating method. The metal film-attached film according to claim 1 or 2, wherein the metal film layer is formed of copper. The method according to claim 1 or 2, wherein the metal film layer has a two-layer structure in which a copper layer is first laminated on the water-soluble resin release layer, and a chromium layer, a nickel-chromium alloy layer or a titanium layer is laminated on the copper layer Wherein the film is a metal film. The metal film-attached film according to claim 1 or 2, wherein the thickness of the metal film layer is 50 nm to 5000 nm. The metal film-attached film according to claim 1 or 2, wherein the release layer has a layer thickness of 0.1 mu m to 20 mu m. 3. The metal film-attached film according to claim 1 or 2, wherein the layer thickness of the support layer is 10 mu m to 70 mu m. An adhesive film with a metal film, wherein a layer of a curable resin composition is formed on a metal film layer of the metal film-attached film according to claim 1. The adhesive film with a metal film as set forth in claim 12, wherein the curable resin composition layer is a prepreg impregnated in a sheet-like reinforcing base material composed of a curable resin composition. The metal film-attached film according to claim 1 or 2 is laminated on the curable resin composition layer formed on the inner layer circuit board so that the metal film layer is in contact with the surface of the curable resin composition layer to cure the curable resin composition, A step of peeling the support layer and irradiating a laser beam onto the release layer formed of a water-soluble resin present on the metal film layer to form a blind via. The method according to claim 14, further comprising a step of dissolving and removing a release layer formed of a water-soluble resin present on the metal film layer in an aqueous solution after forming the blind via. 15. The method of claim 14, wherein the laser is a carbon dioxide gas laser. 15. The method according to claim 15, further comprising forming a conductor layer on the metal film layer by plating. The adhesive film with a metal film according to claim 12 or 13 is laminated so that the curable resin composition layer is in contact with the surface of the inner layer circuit board and the curable resin composition is cured to form an insulating layer and then the support layer is peeled And a step of irradiating a laser beam onto the release layer formed of a water-soluble resin present on the metal film layer to form a blind via. 19. The method according to claim 18, further comprising a step of dissolving and removing a release layer formed of a water-soluble resin present on the metal film layer in an aqueous solution after forming the blind via. 19. The method of claim 18, wherein the laser is a carbon dioxide gas laser. 20. The method of claim 19, further comprising forming a conductor layer on the metal film layer by plating.
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