TW201611701A - Method of manufacturing circuit board - Google Patents

Abstract

To provide a technique of enabling reduction in dimension of an area having a large degree of roughness occurring around a via hole opening portion when manufacturing a circuit board having a small-diameter via hole. A method of manufacturing a circuit board comprises: (A) a step of laminating, on an inner layer board, a resin sheet having a supporting medium which contains a plastic film supporting medium and a resin composition layer joined to the plastic film support medium so that the resin composition layer is joined to the inner layer board; (B) a step of thermosetting the resin composition layer to form an insulation layer, the adhesion strength between the insulation layer and the plastic film supporting medium ranging from 2 to 18 gf/cm; (C) a step of irradiating the plastic film supporting medium with a laser beam from above to form a via hole having a top diameter of 40 [mu]m or less in the insulation layer; (D) a step of performing a desmear treatment; (E) a step of exfoliating the plastic film supporting medium; and (F) a step of forming a conductor layer on the surface of the insulation layer.

Description

Circuit board manufacturing method

The present invention relates to a method of manufacturing a circuit board.

The circuit board is widely used in various electronic devices. Due to the miniaturization and high performance of electronic devices, the wiring of the circuit is required to be finer and higher. As a manufacturing technique of a circuit board, a manufacturing method of a build-up method in which an insulating layer and a conductor layer are alternately stacked on an inner layer substrate is known. In the production method of the build-up method, the insulating layer is laminated on the inner layer substrate by using a resin sheet or the like containing the support of the support and the resin composition layer, for example, to form a resin composition. The layer is formed by thermal hardening. Next, the via hole is formed by performing the hole forming process on the formed insulating layer, and the desmear treatment is performed, and at the same time, the resin residual liquid (slag) inside the via hole is removed and the surface of the insulating layer is roughened (for example) , Patent Document 1).

[Previous Technical Literature] [Patent Document]

[Patent Document 1] JP-A-2008-37957

In the method of manufacturing a build-up method, after the desmear treatment, a conductor layer is formed on the surface of the insulating layer. In this case, if the unevenness of the surface of the insulating layer after the desmear treatment is large, the circuit wiring is prevented from being fined. Therefore, the thickness of the surface of the insulating layer should be sufficient to achieve sufficient adhesion strength (peeling strength) to the conductor layer. The range is low. In this regard, the present inventors have found that when a circuit board is manufactured using a resin sheet with a support, the desmear treatment is performed in a state in which a support is adhered to the insulating layer, whereby a low thickness and a conductor layer can be formed. The insulation layer with high adhesion strength. According to such a technique, in the desmear treatment, since the surface of the insulating layer is greatly restrained from damage, a wide range of desmear treatment methods and desmear treatment conditions can be employed regardless of the resin composition constituting the insulating layer. What is the composition of the material, it can also effectively remove the glue.

On the other hand, in order to increase the density of the circuit wiring, the via hole tends to have a small diameter. When a circuit board having a small-diameter via hole is manufactured by the above-described technique of performing desmear treatment in a state in which a support is adhered to an insulating layer, a small-diameter path is easily formed by laser irradiation during the hole drilling process. From the perspective of the hole, the support body should be a plastic film support. However, the present inventors have found that when the desmear treatment is performed in a state in which the plastic film support is adhered to the insulating layer, there is a region having a larger thickness than the other regions around the opening of the via hole (also referred to as a region). The case of "large area". Such a large-thickness region is formed only around the opening of the via hole, but when a via hole having a small diameter (especially, the top surface of the insulating layer has a diameter of 40 μm or less) is used, the fine circuit corresponding to it is matched. A line is formed around the via hole, and the influence of the large thickness region is large to the extent that it cannot be ignored. Therefore, when a circuit board having a small-diameter via hole is manufactured by a technique of performing desmear treatment in a state in which a support is adhered to an insulating layer, it is desirable to reduce a large-area region which occurs around the opening of the via hole. Size technology.

An object of the present invention is to provide a technique for performing desmear treatment in a state in which a support is adhered to an insulating layer, and when a circuit board having a via having a small diameter is manufactured, the thickness occurring around the opening of the via hole can be reduced. The technology of the size of large areas.

As a result of intensive evaluation of the above-mentioned problems, the inventors of the present invention have found that the above problems can be solved by manufacturing a circuit board by the following specific method, and finally completed the present invention.

That is, the present invention includes the following contents.

[1] A method of producing a circuit board, comprising: (A) a resin sheet comprising a plastic film support and a resin composition layer bonded to the plastic film support, and a resin composition layer a step of laminating the inner layer substrate, (B) a step of thermally hardening the resin composition layer to form an insulating layer, wherein the adhesion strength of the insulating layer to the plastic film support is 2 gf/ Cm~18gf/cm, (C) a step of irradiating a laser from a plastic film support to form a via hole having a top diameter of 40 μm or less in the insulating layer, (D) a step of performing desmear treatment, (E) a step of peeling off the plastic film support, and (F) a step of forming a conductor layer on the surface of the insulating layer.

[2] The method according to [1], wherein the desmear treatment of the step (D) is a wet desmearing treatment.

[3] The method according to [1] or [2], wherein the step (F) comprises, in order, dry plating on the surface of the insulating layer to form a metal layer, and wet plating on the surface of the metal layer. A conductor layer is formed.

[4] The method according to any one of [1] to [3] wherein the plastic film supporting system is provided with a plastic film support of the release layer.

[5] The method according to any one of [1] to [4] wherein the resin composition layer contains an epoxy resin, a curing agent, and an inorganic filler.

[6] The method according to [5], wherein the inorganic filler has an average particle diameter of from 0.01 μm to 3 μm.

[7] The method according to [5], wherein the inorganic filler has an average particle diameter of from 0.01 μm to 0.4 μm.

[8] The method according to any one of [5] to [7] wherein, when the nonvolatile content in the resin composition layer is 100% by mass, the content of the inorganic filler in the resin composition layer is 40% by mass. %~95% by mass.

[9] The method according to any one of [5] to [8] wherein the inorganic filler is surface-treated with a surface treatment agent.

[10] A circuit board produced by the method according to any one of [1] to [9].

[11] A circuit board comprising: a circuit board including an insulating layer and a conductor layer formed on the insulating layer; wherein a via hole having a top diameter of 40 μm or less is formed in the insulating layer, and a via hole opening around the surface of the insulating layer is formed. The length of the large area is less than 10 μm.

[12] The circuit board according to [11], wherein the surface of the insulating layer has an arithmetic mean roughness Ra of 200 nm or less.

[13] A semiconductor device comprising the circuit board according to any one of [10] to [12].

According to the present invention, when the circuit board having the small-diameter via hole is manufactured by the technique of performing the desmear treatment in a state in which the support is adhered to the insulating layer, the large-scale region occurring around the opening of the via hole can be reduced. The size.

In Fig. 1, (a1) shows an SEM photograph of the surface of the insulating layer around the opening of the via hole, and (b1) shows an SEM photograph of the inside of the dotted line frame in (a1).

In Fig. 2, (a2) shows an SEM photograph of the surface of the insulating layer around the opening of the via hole, and (b2) shows an SEM photograph of the inside of the dotted line frame in (a2).

[Formation of the Invention] <Resin sheet with support>

Before describing in detail the method of manufacturing the circuit board of the present invention, a resin sheet with a support used in the method of the present invention will be described.

The resin sheet with a support used in the method of the present invention comprises a plastic film support and a resin composition layer bonded to the plastic film support.

(plastic film support)

Examples of the material of the plastic film support include polyesters such as polyethylene terephthalate (hereinafter also referred to as "PET") and polyethylene naphthalate (hereinafter also referred to as "PEN"). Acrylates such as carbonate (hereinafter also referred to as "PC"), polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone , polyimine, and the like. Among them, preferred are PET, PEN, and polyimine, and more preferably PET or PEN. In a suitable embodiment, the plastic film supports a PET film support or a PEN film support.

As will be described later, in the method of manufacturing a circuit board of the present invention, a laser is irradiated from the plastic film support to form a via having a small diameter. The plastic film support is preferably capable of absorbing laser energy from the viewpoint that the passage holes can be smoothly formed by laser irradiation. For example, the PEN film support is suitable for the formation of via holes for UV irradiation because of its ultraviolet (UV) absorbability.

The laser energy absorbing property can be imparted or increased by including a laser energy absorbing component in the plastic film support. The laser energy absorbing component is not particularly limited as long as it can absorb the laser used for forming the via hole, and examples thereof include carbon powder, metal compound powder, metal powder, and black dye. The laser energy absorbing component may be used singly or in combination of two or more.

Examples of the carbon powder include powders of carbon black such as furnace black, channel black, acetylene black, hot black, and black, graphite powder, and a mixture of these. Examples of the metal compound powder include titanium oxides such as titanium oxide, magnesium oxides such as magnesium oxide, iron oxides such as iron oxide, nickel oxides such as nickel oxide, zinc oxides such as manganese dioxide and zinc oxide. Oxide, cerium oxide, aluminum oxide, rare earth oxide, cobalt oxide such as cobalt oxide, tin oxide such as tin oxide, tungsten oxide such as tungsten oxide, tantalum carbide, tungsten carbide, boron nitride, nitrogen A powder of bismuth, titanium nitride, aluminum nitride, barium sulfate, rare earth oxysulfide, and the like. Examples of the metal powder include silver, aluminum, lanthanum, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, iridium, ruthenium, tin, titanium, vanadium, tungsten, zinc, and the like. Powder and so on. Examples of the black dye include azo (monoazo, disazo, etc.) dyes, azomethine dyes, anthraquinone dyes, quinoline dyes, ketimine dyes, fluorone dyes, and nitro dyes. , xanthene dye, anthraquinone dye, quinone dye, aminoketone dye, methine dye, anthraquinone dye, coumarin dye, anthrone dye, triphenyl dye, triallylethane dye, phthalocyanine dye , Yingge phenol dye, 吖 Dyes and mixtures of these, and the like. In order to improve the dispersibility, the black dye is preferably a solvent-soluble black dye. Among them, as the laser energy absorbing component, from the viewpoint of laser energy conversion efficiency or versatility of heat, carbon powder is preferable, and carbon black is particularly preferable. In addition, the upper limit of the average particle diameter of the laser energy absorbing component is preferably 20 μm or less, and more preferably 10 μm or less from the viewpoint of efficiently absorbing the laser energy. The lower limit of the average particle diameter is preferably 0.001 μm or more, and more preferably 0.002 μm from the viewpoint of dispersibility. The "average particle diameter" as referred to herein can be measured by a particle size distribution measuring apparatus or a BET method. The BET method is a method in which the molecular weight of the liquid nitrogen is adsorbed on the surface of the powder particles by a known adsorption area, and the specific surface area of the sample is determined from the amount. The average particle diameter can be calculated from the specific surface area determined by the BET method.

When the total amount of the components of the plastic film support is 100% by mass, the content of the laser energy absorbing component is preferably 0.01% by mass or more, and more preferably 0.03% by mass from the viewpoint of smoothly forming the via hole. More preferably, it is 0.05% by mass or more. The upper limit of the content is preferably 40% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less from the viewpoint of obtaining a plastic film support having good flexibility. Further, the laser energy absorbing component may be contained in a release layer to be described later.

As a commercial product of the plastic film support, for example, "Lumirror R56", "Lumirror R80", "Lumirror T6AM" (PET film) manufactured by Toray Industries, and "G2LA" manufactured by Teijin DuPont Film Co., Ltd. "PET film", "Teonex Q83" (PEN film), "Upilex S" (polyimide film) manufactured by Ube Industries Co., Ltd., "Apical AH" manufactured by KANEKA, "Apical NPI" (polyimine film) and the like.

The plastic film support may also be subjected to a matting treatment or a corona treatment on the surface joined to the resin composition layer.

In the step (B) to be described later, the adhesion strength between the insulating layer and the plastic film support can be easily adjusted to a desired range, and the plastic film support is preferably bonded to the resin composition layer. A plastic film support with a release layer attached to the release layer. Examples of the release agent to be used in the release layer include non-polyoxyl-type release agents such as alkyd resins, melamine resins, olefin resins, and urethane resins, and polyfluorene-based release agents. . The release agent may be used singly or in combination of two or more. In the case of producing a resin sheet with a support, the resin varnish exhibits high wettability, and the contact state with the resin composition layer tends to be uniform in all directions, and the release layer preferably contains a non-polyoxygen system. The release layer of the release agent is more preferably a release layer containing an alkyd resin and/or an olefin resin.

The release agent can be classified into a release agent having a low peel strength according to the type of the constituent component, etc., and the release agent having a high peeling strength is high. The so-called heavy release type release agent exhibits a light release type release agent. The peel strength between the agent and the heavy release type release agent is a so-called medium release type release agent. However, in the step (B), from the viewpoint of easily adjusting the adhesion strength to a desired range, it is preferable to peel off. Type of release agent. It also differs depending on the composition of the resin composition layer for forming the insulating layer, the lamination conditions of the step (A), and the conditions of the thermal curing of the step (B). However, as the release agent, the initial adhesion strength can be used. It is preferably 100 (mN/20 mm) or more, more preferably 300 (mN/20 mm) or more, and more preferably 500 (mN/20 mm) or more, 700 (mN/20 mm) or more, 800 (mN/20 mm) or more, and 900. A release agent (mN/20mm) or more or 1000 (mN/20mm) or more. The upper limit of the initial adhesion strength is not particularly limited. However, from the viewpoint of smoothly peeling off the plastic film support in the step (E), it is usually 8000 (mN/20 mm) or less and 7500 (mN/20 mm) or less. Wait. In the initial adhesion strength, a 2 kg roller can be used, and an acrylic adhesive tape ("31B" manufactured by Nitto Denko Co., Ltd.) is attached to the surface of the release agent by the release agent, and after being left for 30 minutes, the end of the acrylic adhesive tape is peeled off. It was obtained by grasping with a jig and measuring the load (mN/20 mm) at the time of tearing at room temperature, a speed of 30 cm/min, and a peeling angle of 180°. The measurement can be carried out, for example, by using a tensile tester such as "AC-50C-SL" manufactured by TSE.

As a commercially available product of the release agent, for example, "X" (a polyoxon-containing alkyd resin-based release agent; 490 mN/20 mm) and "SK-1" (containing a polyfluorene) manufactured by LINTEC Co., Ltd. Oxygen alkyd resin release agent; 1250mN/20mm), "AL-5" (non-polyoxyl/alkyd resin release agent; 1480mN/20mm), "6050" (non-polyoxyl/alkyd) Resin-based release agent; 2400mN/20mm), "6051" (non-polyoxyl/alkyd resin release agent; 2800mN/20mm), "6052" (non-polyoxyl/alkyd resin release agent; 4000mN/20mm), etc. (in the brackets, the value of the initial adhesion strength is shown). As a commercially available product of the release agent, "AL-7" (non-polyoxyl/alkyd resin-based release agent; heavy release type) manufactured by LINTEC Co., Ltd., and Fujimori Industrial Co., Ltd. NSP-4" (non-polyoxyl/alkyd resin-based release agent; heavy release type).

The thickness of the plastic film support is not particularly limited, but is preferably The range of 10 μm to 100 μm, more preferably 15 μm to 75 μm. In particular, from the viewpoint of facilitating the formation of the small-diameter through-holes, it is more preferably 20 μm to 50 μm. Further, when the plastic film support is a plastic film support having a release layer, the thickness of the entire plastic film support having the release layer is preferably in the above range.

(resin composition layer)

The resin composition used for the resin composition layer is not particularly limited as long as the cured product has sufficient hardness and insulation properties and brings about the desired adhesion strength to the plastic film support. For example, a resin composition containing an epoxy resin, a hardener, and an inorganic filler can be used. The resin composition used for the resin composition layer may further contain additives such as a thermoplastic resin, a hardening accelerator, a flame retardant, and an organic filler, as needed.

- epoxy resin -

Examples of the epoxy resin include bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol AF epoxy resin, and dicyclopentadiene epoxy resin. , trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolak type epoxy resin, t-butyl catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin,蒽 type epoxy resin, epoxy propyl amine type epoxy resin, epoxy propyl ester type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, Epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, epoxy resin containing a spiro ring, cyclohexane Di-methanol type epoxy resin, naphthyl ether type epoxy resin and trishydroxymethyl type epoxy resin. The epoxy resin may be used singly or in combination of two or more.

The epoxy resin is preferably an epoxy resin containing two or more epoxy groups in one molecule. When the nonvolatile content of the epoxy resin is 100% by mass, it is preferably at least 50% by mass or more of an epoxy resin having two or more epoxy groups in one molecule. In particular, it is preferable to include an epoxy resin having two or more epoxy groups in one molecule and a liquid at a temperature of 20 ° C (hereinafter referred to as "liquid epoxy resin"), and having 3 molecules in one molecule. One or more epoxy groups are solid epoxy resins (hereinafter referred to as "solid epoxy resins") at a temperature of 20 ° C. As the epoxy resin, a liquid epoxy resin and a solid epoxy resin are used in combination to obtain a resin composition having excellent flexibility. Further, the breaking strength of the cured product of the resin composition is also increased.

The liquid epoxy resin is preferably a bisphenol A epoxy resin, a bisphenol F epoxy resin, a naphthalene epoxy resin, a glycidyl ester epoxy resin, or a phenol novolak epoxy resin. The epoxy resin having a butadiene structure is more preferably a bisphenol A type epoxy resin, a bisphenol F type epoxy resin or a naphthalene type epoxy resin. Specific examples of the liquid epoxy resin include "HP4032", "HP4032H", "HP4032D", "HP4032SS" (naphthalene epoxy resin) manufactured by DIC Co., Ltd., and "Mitsubishi Chemical Co., Ltd." jER828EL (bisphenol A type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolak type epoxy resin), "ZX1059" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. (bisphenol A) "EX-721" (epoxypropyl ester type epoxy resin) manufactured by Nagase Chemtex Co., Ltd., and DAICEL Chemical Industry Co., Ltd. PB-3600" (epoxy resin with butadiene structure). These may be used alone or in combination of two or more.

As the solid epoxy resin, a naphthalene type tetrafunctional epoxy resin, a cresol novolak type epoxy resin, a dicyclopentadiene type epoxy resin, a trisphenol type epoxy resin, a naphthol type epoxy resin is preferable. , a biphenyl type epoxy resin, a naphthyl ether type epoxy resin, a fluorene type epoxy resin, more preferably a naphthalene type 4-functional epoxy resin, a naphthol type epoxy resin, and a biphenyl type epoxy resin. Specific examples of the solid epoxy resin include "HP-4700" manufactured by DIC Co., Ltd., "HP-4710" (naphthalene type 4-functional epoxy resin), and "N-690" (cresol novolac varnish). Type epoxy resin), "N-695" (cresol novolac type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "EXA7311", "EXA7311-G3", " "EXA7311-G4S", "EXA7311-G4S", "HP6000" (stretching naphthalene ether type epoxy resin), "EPPN-502H" (trisphenol type epoxy resin) made by Nippon Kayaku Co., Ltd., "NC7000L" (naphthol novolak type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), "ESN475V" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd. "Phenol type epoxy resin", "ESN485V" (naphthol novolac type epoxy resin), "YX4000H" made by Mitsubishi Chemical Corporation, "YL6121" (biphenyl type epoxy resin), "YX4000HK" (Joint 2) Methyl phenol type epoxy resin), "YX8800" (蒽 type epoxy resin) "PG-100", "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., and "YL7800" (茀-type epoxy resin) manufactured by Mitsubishi Chemical Corporation.

When the epoxy resin and the solid epoxy resin are used together, the ratio (liquid epoxy resin: solid epoxy resin) is preferably 1:0.1 to 1:6 by mass ratio. The scope. When the ratio of the amount of the liquid epoxy resin to the solid epoxy resin is such a range, (i) when used in the form of a resin sheet, moderate adhesion is obtained, and (ii) when used in the form of a resin sheet In addition, sufficient flexibility is obtained, workability is improved, and (iii) an effect of obtaining a cured product having sufficient fracture strength or the like is obtained. From the viewpoints of the effects (i) to (iii) above, the ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is preferably a mass ratio. The range of 1:0.3~1:5 is particularly preferably in the range of 1:0.6~1:4.5.

The content of the epoxy resin in the resin composition is preferably from 3% by mass to 40% by mass, more preferably from 5% by mass to 35% by mass, even more preferably from 10% by mass to 30% by mass.

In the present invention, the content of each component in the resin composition is a value when the nonvolatile content in the resin composition is 100% by mass, unless otherwise specified.

The epoxy equivalent of the epoxy resin is preferably from 50 to 3,000, more preferably from 80 to 2,000, and particularly preferably from 110 to 1,000. By being in this range, the crosslinking density of the cured product becomes sufficient, and an insulating layer having a small surface roughness can be obtained. Further, the epoxy equivalent system can be measured in accordance with JIS K7236 and is a mass of a resin containing 1 equivalent of an epoxy group.

The weight average molecular weight of the epoxy resin is preferably from 100 to 5,000, more preferably from 250 to 3,000, and particularly preferably from 400 to 1,500. Here, the weight average molecular weight of the epoxy resin is a polystyrene-equivalent weight average molecular weight measured by a gel permeation chromatography (GPC) method.

-hardener-

The curing agent is not particularly limited as long as it has a function of curing the epoxy resin, and examples thereof include a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, and benzo. It is a hardener and a cyanate-based hardener. The curing agent may be used singly or in combination of two or more.

The phenol-based curing agent and the naphthol-based curing agent are preferably a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolac structure from the viewpoint of heat resistance and water resistance. Moreover, from the viewpoint of the adhesion strength to the conductor layer, a nitrogen-containing phenol-based curing agent or a nitrogen-containing naphthol-based curing agent is preferable, and more preferably contains three. Skeletal phenolic hardener or contains three A naphthol-based hardener of the skeleton. Among them, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion strength to the conductor layer, it is preferable to contain three Skeletal phenol novolac resin. These may be used alone or in combination of two or more.

Specific examples of the phenol-based curing agent and the naphthol-based curing agent include "MEH-7700", "MEH-7810", "MEH-7851", and Nippon Chemical Co., Ltd., manufactured by Akwa Kasei Co., Ltd. "SNN", "SN-180", "SN-180", "SNT190", "SN-475", "NHN", "CBN", "GPH", and Dongdu Chemicals Co., Ltd. "LA-7052", "LA-7054", "LA-3018", "LA-1356", "SN-485", "SNP495", "SN-375", "SN-395", DIC (share) system "Wait.

From the viewpoint of improving the adhesion strength to the conductor layer, an active ester-based curing agent is also preferred. The active ester-based curing agent is particularly limited, but it is generally preferable to use two phenol esters, thiophenol esters, N-hydroxylamine esters, and esters of a heterocyclic hydroxy compound in one molecule. The above compound having a high reactivity and an ester group. The active ester-based curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound with a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improvement in heat resistance, an active ester-based curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred. More preferably, it is an active ester type hardener obtained from a carboxylic acid compound, a phenol compound, and/or a naphthol compound. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of the phenol compound or the naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, and methyl group. Bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2 ,6-dihydroxynaphthalene, dihydroxydiphenyl ketone, trihydroxydiphenyl ketone, tetrahydroxydiphenyl ketone, phloroglucinol, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolac Wait. Here, the "dicyclopentadiene type diphenol compound" means a diphenol compound obtained by condensing two molecules of phenol with respect to one molecule of dicyclopentadiene.

The active ester-based curing agent is preferably an active ester compound containing a dicyclopentadiene-type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated phenol novolak, and a phenol novolac. The active ester compound of the benzamidine compound is more preferably an active ester compound containing a naphthalene structure or an active ester compound containing a dicyclopentadiene type diphenol structure. These may be used alone or in combination of two or more. In addition, the "dicyclopentadiene type diphenol structure" is a divalent structural unit represented by a phenylene-dicyclopentene-phenylene group.

As a commercial product of the active ester-based curing agent, "EXB9451", "EXB9460", "EXB9460S", and "HPC-8000-65T" are mentioned in the active ester compound containing a dicyclopentadiene type diphenol structure. (DIC), in the active ester compound containing a naphthalene structure, "EXB9416-70BK" (manufactured by DIC) can be used in an active ester compound containing an acetal of a phenol novolak. "DC808" (manufactured by Mitsubishi Chemical Corporation), and "YLH1026" (manufactured by Mitsubishi Chemical Corporation) and the like are used as the active ester compound of the benzamidine compound containing a phenol novolak.

Benzo Specific examples of the curing agent include "HFB2006M" manufactured by Showa Polymer Co., Ltd., and "Pd" and "Fa" manufactured by Shikoku Chemical Industries Co., Ltd.

The cyanate-based curing agent is not particularly limited, and examples thereof include a novolac type (phenol novolac type, an alkylphenol novolak type, etc.) cyanate-based curing agent and dicyclopentadiene-type cyanogen. An acid ester hardener, a bisphenol type (bisphenol A type, bisphenol F type, bisphenol S type, etc.) cyanate type curing agent, and a part thereof Compounds, etc. Specific examples include bisphenol A dicyanate and polyphenol cyanate (oligo(3-methylene-1,5-phenylene)) and 4,4'-methylene. Bis(2,6-dimethylphenyl cyanate), 4,4'-ethylenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis (4 -Cyanate ester)Phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-double 2-functional (4-cyanate phenyl-1-(methylethylidene)) benzene, bis(4-cyanate phenyl) sulfide, and bis(4-cyanate phenyl) ether a polyfunctional cyanate resin derived from a cyanate resin, a phenol novolac, a cresol novolac, or the like, and a cyanate resin thereof Compounds, etc. As a commercially available product of a cyanate-based curing agent, "PT30" and "PT60" (all phenol novolac type polyfunctional cyanate resins) manufactured by LONZA Japan Co., Ltd., and "BA230" (bisphenol A) are mentioned. One or all of the dicyanate It becomes a prepolymer of a trimer).

The ratio of the epoxy resin to the hardener is from the viewpoint of improving the mechanical strength or water resistance of the obtained insulating layer, [the total number of epoxy groups of the epoxy resin]: [the total number of reactive groups of the hardener] The ratio is preferably in the range of 1:0.2 to 1:2, more preferably in the range of 1:0.3 to 1:1.5, and particularly preferably in the range of 1:0.4 to 1:1. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group or the like, which varies depending on the kind of the curing agent. Further, the total number of epoxy groups of the epoxy resin is a value obtained by dividing the mass of the solid content of each epoxy resin by the epoxy equivalent, and the total value of all the epoxy resins is the reaction of the hardener. The sum of the bases is to harden each The value of the solid content of the agent divided by the equivalent of the reactive group, and the total value of all the hardeners.

-Inorganic filler -

The inorganic filler is not particularly limited, and examples thereof include vermiculite, alumina, glass, cordierite, cerium oxide, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, and calcium carbonate. , magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, barium titanate, barium titanate, calcium titanate, magnesium titanate, barium titanate, titanium oxide, barium zirconate, zirconium Calcium acid, zirconium phosphate and zirconium tungstate phosphate. Among these, it is particularly suitable as a vermiculite such as amorphous vermiculite, molten vermiculite, crystalline vermiculite, synthetic vermiculite, hollow vermiculite or the like. Further, as the vermiculite, a spherical vermiculite is preferred. The inorganic filler may be used singly or in combination of two or more. As a commercially available spherical molten vermiculite, "SOC2" and "SOC1" manufactured by ADMATECHS can be cited.

From the viewpoint of obtaining an insulating layer on which fine circuit wiring can be formed, the average particle diameter of the inorganic filler is preferably 3 μm or less, more preferably 1 μm or less, still more preferably 0.7 μm or less, and even more preferably 0.5 μm or less, 0.4 μm or less, or 0.3 μm or less. The lower limit of the average particle diameter of the inorganic filler is preferably 0.01 μm or more, and more preferably 0.03 μm or more, from the viewpoint of obtaining a resin varnish having a moderate viscosity and a resin varnish. It is particularly preferably 0.05 μm or more, more preferably 0.07 μm or more, and particularly preferably 0.1 μm or more. The average particle size of the inorganic filler can be based on the Mie scattering theory. The laser diffraction ‧ scattering method was used for the measurement. Specifically, the particle size distribution of the inorganic filler can be determined on a volume basis by a laser diffraction scattering type particle size distribution measuring apparatus, and the median diameter can be measured as an average particle diameter. The measurement sample is preferably one in which an inorganic filler is dispersed in a solvent via ultrasonic waves. As the laser diffraction scattering type particle size distribution measuring apparatus, "LA-500", "LA-750", "LA-950", etc., which are manufactured by Horiba, Ltd., can be used.

From the viewpoint of further reducing the size of a region having a large thickness around the opening of the via hole, it is preferable to use an inorganic filler which removes coarse particles by classification. In one embodiment, it is preferable to use an inorganic filler which removes particles having a particle diameter of 10 μm or more by classification, and it is more preferable to use an inorganic filler which removes particles having a particle diameter of 5 μm or more by classification, and it is more preferable to use a classification. On the other hand, the inorganic filler of particles having a particle diameter of 3 μm or more is removed.

In a preferred embodiment, an inorganic filler having an average particle diameter of 0.01 μm to 3 μm and having particles having a particle diameter of 10 μm or more removed by classification is used.

From the viewpoint of improving dispersibility and moisture resistance, the inorganic filler is preferably surface-treated with a surface treatment agent from the viewpoint of further reducing the size of a region having a large thickness around the opening of the via hole. Examples of the surface treatment agent include an amino decane coupling agent, an epoxy decane coupling agent, a mercapto decane coupling agent, a decane coupling agent, an organic decane compound, and a titanate coupling agent. The surface treatment agent may be used singly or in combination of two or more. As a commercially available product of the surface treatment agent, "KBM403" (3-glycidoxypropyltrimethoxydecane) manufactured by Shin-Etsu Chemical Co., Ltd., and "KBM803" manufactured by Shin-Etsu Chemical Co., Ltd. 3-mercaptopropyl "Ketium methoxy decane", "KBE903" (3-aminopropyltriethoxy decane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-amine) manufactured by Shin-Etsu Chemical Co., Ltd. "Silyl trimethoxy decane", "SZ-31" (hexamethyldioxane) manufactured by Shin-Etsu Chemical Co., Ltd., etc.

After the surface treatment of the inorganic filler, the amount of carbon per unit area of the surface of the inorganic filler is preferably 0.05 mg/m ² or more, more preferably 0.08 mg/m ² or more, and particularly preferably 0.11 mg/ m ² or more, especially more preferably 0.14mg / m ² or more, particularly preferably 0.17mg / m ² or more, 0.20mg / m ² or more, 0.23mg / m ² or more 0.26mg / m ² or more. The upper limit of the carbon content is preferably 1.00mg / m ² or less, more preferably 0.75mg / m ² or less, and particularly preferably 0.70mg / m ² or less, especially more preferably 0.65mg / m ² or less, 0.60mg / m ² or less, 0.55mg / m ² or less, ² or less 0.50mg / m.

The amount of carbon per unit area of the surface of the inorganic filler can be calculated by the following procedure. Ultrasonic cleaning was carried out by adding a sufficient amount of methyl ethyl ketone (MEK) as a solvent to the inorganic filler after the surface treatment. After removing the supernatant and drying the solid component, the amount of carbon bonded to the surface of the inorganic filler was measured using a carbon analyzer. The amount of carbon per unit area of the inorganic filler is calculated by dividing the obtained carbon amount by the specific surface area of the inorganic filler. Examples of the carbon analyzer include "EMIA-320V" manufactured by Horiba, Ltd., and the like.

The content of the inorganic filler in the resin composition is preferably 40 from the viewpoint of lowering the coefficient of thermal expansion of the insulating layer and preventing cracking or circuit deformation due to a difference in thermal expansion between the insulating layer and the conductor layer. The mass% or more is more preferably 50% by mass or more, and particularly preferably 60% by mass or more. use When the resin composition having a high content of the inorganic filler is used to form the insulating layer, the adhesion strength between the insulating layer and the conductor layer may be lowered. However, the resin composition of the present invention uses a resin composition having a high content of the inorganic filler. At the same time, sufficient adhesion strength between the insulating layer and the conductor layer can be achieved. In the method for producing a circuit board of the present invention, the content of the inorganic filler in the resin composition can be further increased without lowering the adhesion strength between the insulating layer and the conductor layer. For example, the content of the inorganic filler in the resin composition can be increased to 62% by mass or more, 64% by mass or more, 66% by mass or more, 68% by mass or more, or 70% by mass or more.

The upper limit of the content of the inorganic filler is preferably 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 85% by mass or less, from the viewpoint of the mechanical strength of the insulating layer.

In one embodiment, the resin composition used in the resin composition layer contains the above-described epoxy resin, curing agent, and inorganic filler. Wherein, the resin composition preferably contains a mixture of a liquid epoxy resin and a solid epoxy resin (liquid epoxy resin: the quality of the solid epoxy resin is preferably 1:0.1 to 1:6, more preferably 1:0.3~1:5, especially 1:0.6~1:4.5) as an epoxy resin, containing a phenolic curing agent, a naphthol curing agent, an active ester curing agent, and a cyanate curing agent. One or more of the group formed as a curing agent contains vermiculite as an inorganic filler. With respect to the resin composition layer containing such a specific component, the suitable content of the epoxy resin, the hardener, and the inorganic filler is also as described above, wherein the content of the epoxy resin is preferably 5% by mass to 35% by mass, and the inorganic filler is used. The content of the epoxy resin is preferably 40% by mass to 95% by mass, and the content of the epoxy resin is preferably 10% by mass to 30% by mass. %, the content of the inorganic filler is more preferably from 50% by mass to 90% by mass. The content of the curing agent is preferably such that the ratio of the total number of epoxy groups of the epoxy resin to the total of the reactive groups of the curing agent is 1:0.2 to 1:2, more preferably 1:0.3. It is contained in the form of ~1:1.5, and it is especially preferable to be in the form of 1:0.4 to 1:1.

The resin composition used for the resin composition layer may further contain additives such as a thermoplastic resin, a hardening accelerator, a flame retardant, and an organic filler, as needed.

- thermoplastic resin -

Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyolefin resin, polybutadiene resin, polyimine resin, polyamidimide resin, polyether phthalimide resin, and poly Anthracene resin, polyether oxime resin, polyphenylene ether resin, polycarbonate resin, polyether ether ketone resin, polyester resin. The thermoplastic resin may be used singly or in combination of two or more.

The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and particularly preferably in the range of 20,000 to 60,000. The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is determined by a gel permeation chromatography (GPC) method. Specifically, the weight average molecular weight of the thermoplastic resin in terms of polystyrene can be used as a measuring device using LC-9A/RID-6A manufactured by Shimadzu Corporation, and Shodex K-800P/K-804L manufactured by Showa Denko Co., Ltd. /K-804L as a column, using chloroform or the like as the mobile phase at 40 ° C The column temperature was measured and calculated using a calibration curve of standard polystyrene.

The phenoxy resin may, for example, be selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a bisphenol acetophenone skeleton, a novolak skeleton, a biphenyl skeleton, an anthracene skeleton, and a dicyclopentadiene. a phenoxy resin having one or more kinds of skeletons of a skeleton, a norbornene skeleton, a naphthalene skeleton, an anthracene skeleton, an adamantane skeleton, a terpene skeleton, and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any one of a phenolic hydroxyl group and an epoxy group. The phenoxy resin may be used singly or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (all are phenoxy resins containing a bisphenol A skeleton) and "YX8100" (a benzene containing a bisphenol S skeleton) manufactured by Mitsubishi Chemical Corporation. Oxygen resin) and "YX6954" (phenoxy resin containing a bisphenol acetophenone skeleton), "FX280" and "FX293" manufactured by Toho Chemical Co., Ltd., and "YL7553" by Mitsubishi Chemical Co., Ltd. ", YL6794", "YL7213", "YL7290" and "YL7482".

Specific examples of the polyvinyl acetal resin include an electrochemically charged Butyral 4000-2, 5000-A, 6000-C, 6000-EP, and S-LEC manufactured by Sekisui Chemical Industry Co., Ltd. BH series, BX series, KS series, BL series, BM series, etc.

Specific examples of the polyimine resin include "Rikacoat SN20" and "Rikacoat PN20" manufactured by Nippon Chemical and Chemical Co., Ltd. Specific examples of the polyimine resin include a linear reaction obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride. The polyimine (the one described in JP-A-2006-37083) and the polyfluorene-containing polysiloxane (the ones described in JP-A-2002-12667 and JP-A-2000-319386) Polyethylenimine.

Specific examples of the polyamidoximine resin include "Vylomax HR11NN" and "Vylomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of the polyamidoximine resin include modified polyfluorenes such as polyacrylamide skeletons "KS9100" and "KS9300" manufactured by Hitachi Chemical Co., Ltd. Amine quinone.

Specific examples of the polyether oxime resin include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., and the like.

Specific examples of the polyfluorene resin include polydips "P1700" and "P3500" manufactured by Solvay Advanced Polymers Co., Ltd.

The content of the thermoplastic resin in the resin composition is preferably from 0.1% by mass to 20% by mass, more preferably from 0.5% by mass to 10% by mass, even more preferably from 1% by mass to 5% by mass.

- hardening accelerator -

Examples of the curing accelerator include a phosphorus-based curing accelerator, an amine-based curing accelerator, an imidazole-based curing accelerator, and an lanthanum-based curing accelerator. Preferred examples are a phosphorus-based curing accelerator, an amine-based curing accelerator, and an imidazole. A hardening accelerator. The curing accelerator may be used singly or in combination of two or more. When the total amount of the non-volatile components of the epoxy resin and the curing agent is 100% by mass, the content of the curing accelerator is preferably from 0.05% by mass to 3% by mass.

- Flame retardant -

Examples of the flame retardant include an organic phosphorus-based flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a xenon-based flame retardant, and a metal hydroxide. The flame retardant may be used singly or in combination of two or more. The content of the flame retardant in the resin composition is not particularly limited, but is preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 9% by mass.

-Organic filler -

As the organic filler, any organic filler which can be used in forming the insulating layer of the circuit board can be used, and examples thereof include rubber particles, polyamide fine particles, and polyfluorene oxide particles, and rubber particles are preferable.

The rubber particles are not particularly limited as long as they are chemically cross-linked to a resin exhibiting rubber elasticity, and are fine particles which are insoluble and infusible in an organic solvent, and examples thereof include acrylonitrile. Ethylene rubber particles, butadiene rubber particles, acrylic rubber particles, and the like. Specific examples of the rubber particles include XER-91 (manufactured by Nippon Synthetic Rubber Co., Ltd.), Staphyloid AC3355, AC3816, AC3816N, AC3832, AC4030, AC3364, IM101 (above, AICA Industrial Co., Ltd.), Paraloid EXL 2655, EXL2602 (above, Wu Yu Chemical Industry Co., Ltd.) and so on.

The average particle diameter of the organic filler is preferably in the range of 0.005 μm to 1 μm, more preferably in the range of 0.2 μm to 0.6 μm. Average grain of organic filler The diameter system can be measured using dynamic light scattering. For example, the organic filler can be uniformly dispersed in a suitable organic solvent by ultrasonic wave or the like, and a thick particle size analyzer ("FPAR-1000" manufactured by Otsuka Electronics Co., Ltd.) can be used to form an organic filler on a mass basis. The particle size distribution was measured by taking the median diameter as the average particle diameter. The content of the organic filler in the resin composition is preferably from 1% by mass to 10% by mass, more preferably from 2% by mass to 5% by mass.

-Other ingredients -

The resin composition used for the resin composition layer may contain other components as needed. Examples of such other components include organometallic compounds such as organic copper compounds, organozinc compounds, and organic cobalt compounds, and tackifiers, antifoaming agents, leveling agents, adhesion imparting agents, colorants, and hardenability. Resin additives such as resins.

The thickness of the resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, still more preferably 60 μm or less, even more preferably 50 μm or less, and still more preferably 40 μm or less from the viewpoint of the reduction in thickness of the circuit board. In particular, from the viewpoint of facilitating the formation of the small-diameter through-holes, it is preferably 30 μm or less, more preferably 20 μm or less, and still more preferably 15 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but is usually 3 μm or more.

In the resin sheet with a support, the resin composition layer may have a multi-layer structure composed of two or more layers. When the resin composition layer of the multi-layer structure is used, the thickness of the entire layer is preferably in the above range.

The resin sheet with the support can be formed on the plastic film support It is produced by forming a resin composition layer.

The resin composition layer can be formed on the plastic film support by a well-known method. For example, a resin varnish in which a resin composition is dissolved in a solvent can be prepared, and the resin varnish is applied onto the surface of the plastic film support by a coating device such as a die coater, and the coating film is dried to provide a resin composition layer.

Examples of the solvent used for the preparation of the resin varnish include ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, and propylene glycol monomethyl ether acetate. Acetate solvent such as ester and carbitol acetate, carbitol solvent such as cellosolve and butyl carbitol, aromatic hydrocarbon solvent such as toluene and xylene, dimethylformamidine A guanamine-based solvent such as an amine, dimethylacetamide or N-methylpyrrolidone. The solvent may be used singly or in combination of two or more.

The drying of the coating film can be carried out by a well-known drying method such as heating or hot air blowing. When the solvent remains in the resin composition layer, the amount of residual solvent in the resin composition is usually dried to 10% by mass or less, preferably 5% by mass or less. Although depending on the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing 30% by mass to 60% by mass of a solvent is used, the resin can be formed by drying at 50 ° C to 150 ° C for 3 to 10 minutes. Composition layer.

In the resin sheet with the support, the surface of the resin composition layer which is not bonded to the plastic film support (that is, the side opposite to the plastic film support) can be laminated to the plastic film support. membrane. Protective film The thickness is not particularly limited and may be, for example, 1 μm to 40 μm. By laminating the protective film, adhesion or damage to the surface of the resin composition layer or the like by dust or the like can be prevented. The resin sheet with a support can be wound up and stored in a roll shape, and can be used by peeling off a protective film at the time of manufacturing a circuit board.

[Method of Manufacturing Circuit Board]

The method for manufacturing a circuit board of the present invention comprises the following steps (A) to (F) in order: (A) a support comprising a plastic film support and a resin composition layer bonded to the plastic film support; a resin sheet in which a resin composition layer is bonded to an inner layer substrate, a step of laminating the inner layer substrate, and (B) a step of thermally curing the resin composition layer to form an insulating layer, wherein the insulating layer and the plastic film are formed The bonding strength of the support is 2gf/cm~18gf/cm, (C) the laser is irradiated from the plastic film support, and the via hole having a top diameter of 40 μm or less is formed in the insulating layer, and (D) the desmear treatment is performed. And (E) the step of peeling off the plastic film support, and (F) the step of forming a conductor layer on the surface of the insulating layer.

In the present invention, the "in order of inclusion" as used in the steps (A) to (F) is as long as it is the steps including the steps (A) to (F) and the steps (A) to (F). In this order, other steps can be included. The same applies to the "in order of inclusion" stated in the steps or processing.

The present inventors have found that when a circuit board is manufactured using a resin sheet with a support, the desmear treatment is performed in a state in which a support is adhered to the insulating layer, whereby a low-thickness and adhesion strength to the conductor layer can be formed. Insulation. However, as described above, the present inventors have found that when the desmear treatment is performed in a state in which the plastic film support is adhered to the insulating layer, there is a region having a larger thickness than the other regions around the opening of the via hole (" The case of a large area). Such a large-thickness region is formed only around the opening of the via hole, but when a via hole having a small diameter (especially, the top diameter of the surface of the insulating layer is 40 μm or less) is used, the fine circuit wiring corresponding thereto is used. It is formed around the via hole, and the influence of the large thickness region is large to the extent that it cannot be ignored. In order to achieve higher density of circuit wiring, there is a need for a technique capable of reducing the size of a region having a large thickness around the opening of the via hole.

The inventors of the present invention discovered the adhesion strength between the insulating layer formed by thermal curing and the plastic film support in the process of reviewing the technique of reducing the size of the region having a large thickness around the opening of the via hole (ie, the step (B) The adhesion strength between the obtained insulating layer and the plastic film support) affects the size of a large-thickness region. Then, it has been found that the size of the region having a large thickness can be reduced by setting the adhesion strength to a predetermined value or more.

In the two embodiments in which the adhesion strength between the insulating layer and the plastic film support is different, the opening of the via hole after the desmear treatment is applied to the insulating layer with the plastic film support attached thereto is shown in FIG. 1 and FIG. Scanning electron microscope (SEM) photograph of the surrounding insulating layer surface. Furthermore, Figures 1 and 2 are shown for reference, and the comparison is relatively large (top straight) Path hole with a diameter of 50 μm).

Fig. 1 shows an SEM photograph of an embodiment in which the adhesion strength between the insulating layer and the plastic film support is lower than the range desired in the present invention (i.e., 2 to 18 gf/cm) (comparative embodiment). In Fig. 1, (a1) is a SEM photograph of the surface of the insulating layer around the opening of the via hole after the desmear treatment, and (b1) is an SEM photograph showing the inside of the dotted line frame in (a1). In the embodiment of Fig. 1, it is clearly confirmed that a region having a larger thickness than the other regions (a region having a large thickness) is formed around the opening portion of the via hole. As can be grasped from Fig. 1, a large-thickness region is formed concentrically with the via hole so as to surround the opening of the via hole. In the present invention, the size of the large-diameter region is evaluated by the "length of the large-thickness region" (L _r ), which is the radius r1 of the opening portion (inner circle) of the via hole and the outer edge of the region having a large thickness ( The difference between the radius r2 of the outer circle (r2-r1). In the embodiment of Fig. 1, it is confirmed that the length (L _r ) of the region having a large thickness exceeds 10 μm.

Fig. 2 is a SEM photograph showing an embodiment in which the adhesion strength between the insulating layer and the plastic film support is within the desired range (i.e., 2 to 18 gf/cm) in the present invention. In Fig. 2, (a2) is a SEM photograph of the surface of the insulating layer around the opening of the via hole after the desmear treatment, and (b2) is an SEM photograph showing the inside of the dotted line frame in (a2). In the embodiment of Fig. 2, the length (L _r ) of the region having a large thickness occurring around the via hole is about 2 μm, and it has been confirmed that the size of the region having a large thickness is remarkably reduced.

Hereinafter, each step will be described.

<Step (A)>

In the step (A), the resin sheet containing the support of the plastic film support and the resin composition layer bonded to the plastic film support is laminated on the resin composition layer and the inner substrate. Inner substrate.

The composition of the resin sheet with the support used in the step (A) is as described above. In addition, the "inner substrate" mainly refers to a substrate such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, or a thermosetting polyphenylene ether substrate, or A substrate of a patterned conductor layer (circuit) is formed on one or both sides of the substrate. Further, in the case of manufacturing a circuit board, an inner layer circuit board of an intermediate product which is required to form an insulating layer and/or a conductor layer is also included in the "inner substrate" as used in the present invention.

The lamination of the resin sheet with the support and the inner substrate can be carried out, for example, by heating and pressing the resin sheet with the support to the inner substrate from the side of the plastic film support. The member which heat-press-bonds the resin sheet with a support to the inner-layer board|substrate (it is also called the "heat-pressure- )Wait. In addition, it is preferable that the heating and pressure-bonding member is not directly pressed against the resin sheet with the support, and the resin composition layer sufficiently follows the surface unevenness of the inner layer substrate, and the elastic material such as heat-resistant rubber is interposed. Pressurize.

The heating and pressing temperature is preferably from 80 ° C to 160 ° C, more preferably from 90 ° C to 140 ° C, particularly preferably from 100 ° C to 120 ° C, and the heating pressure is preferably from 0.098 MPa to 1.77 MPa, more preferably 0.29. In the range of MPa~1.47MPa, the heating and pressing time is preferably from 20 seconds to 400 seconds, more preferably 30 seconds. 300 seconds range. The lamination is preferably carried out under reduced pressure of 26.7 hPa or less.

The lamination system can be carried out by a commercially available vacuum laminator. As a commercially available vacuum laminator, for example, a vacuum press laminator manufactured by Nippon Machine Co., Ltd., a vacuum applicator manufactured by Nichigo-Morton Co., Ltd., or the like can be given.

In the step (A), the resin sheet with the support may be laminated on one side of the inner layer substrate or may be laminated on both sides.

After lamination, the heated pressure-bonding member is pressurized under normal pressure (at atmospheric pressure), for example, from the side of the plastic film support, and the resin sheet of the laminated support may be smoothed. The pressurization conditions of the smoothing treatment may be the same conditions as the above-described laminated heat-pressing conditions. The smoothing treatment can be carried out by a commercially available vacuum laminator. Further, the lamination and smoothing treatment can be continuously performed using the commercially available vacuum laminator.

<Step (B)>

In the step (B), the resin composition layer is thermally cured to form an insulating layer. This step (B) is characterized in that the adhesion strength between the obtained insulating layer and the plastic film support is 2 gf/cm to 18 gf/cm.

The step (B) is carried out so that the adhesion strength between the obtained insulating layer and the plastic film support is 2 gf/cm or more, from the viewpoint of reducing the size of the region having a large thickness occurring around the opening of the via hole. It is preferably 2.5 gf/cm or more, more preferably 3 gf/cm or more, 3.5 gf/cm or more, 4 gf/cm or more, 4.5 gf/cm or more, or 5 gf/cm or more. If the adhesion strength is too high, the plastic is peeled off in the step (E) described later. In the case of the film support, the plastic film support body is cut by the via hole as a starting point, and a part of the plastic film support remains on the surface of the insulating layer. From the viewpoint that the plastic film support does not remain and the plastic film support can be easily peeled off, the upper limit of the adhesion strength is 18 gf/cm or less, preferably 17 gf/cm or less, more preferably 16 gf/cm or less or 15 gf. /cm below. The adhesion strength between the insulating layer obtained in the step (B) and the plastic film support can be measured by the method described in the section "Measurement of the adhesion strength between the insulating layer and the plastic film support".

In the step (B), the thermosetting condition of the resin composition layer is not particularly limited as long as the desired adhesion strength is obtained. For example, the thermosetting condition of the resin composition layer may be in the range of 120 ° C to 240 ° C (preferably 150 ° C to 210 ° C) depending on the type of the plastic film support, the composition of the resin composition layer, and the like. The range is more preferably in the range of 160 ° C to 200 ° C. The hardening time is in the range of 5 minutes to 90 minutes (preferably 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes) to obtain the above desired The way of the adhesion strength is appropriately determined. Further, the pressure at the time of thermosetting is not particularly limited, and any of the above-mentioned desired adhesion strength may be any of normal pressure, pressure, and reduced pressure.

The resin composition layer may be preheated at a temperature lower than the hardening temperature before the resin composition layer is thermally cured. For example, before the resin composition layer is thermally cured, the resin composition layer may be preheated for 5 minutes or more at a temperature of 50 ° C or more and less than 120 ° C (preferably 60 ° C or more and 110 ° C or less). Good for 5 minutes to 150 minutes).

By the adhesion strength between the obtained insulating layer and the plastic film support By performing the step (B) in such a manner as to specify the range described above, it is possible to reduce the size of a region having a large thickness which occurs around the opening of the via hole.

<Step (C)>

In the step (C), a laser is irradiated from the plastic film support, and a via hole having a top diameter of 40 μm or less is formed in the insulating layer.

The diameter of the top of the via hole formed in the step (C) (the opening diameter on the surface of the insulating layer) is preferably less than 40 μm, more preferably 35 μm or less, from the viewpoint of higher density of the circuit wiring. Good is 30μm or less. By adopting the method of the present invention of the above step (B), the size of the large-diameter region occurring around the opening portion of the via hole can be reduced, and even if a smaller-diameter via hole is used, the fine circuit corresponding thereto can be used. Wiring is formed around the via hole. In the method of the present invention, for example, a channel having a top diameter of 28 μm or less, 26 μm or less, 24 μm or less, 22 μm or less, 20 μm or less, 18 μm or less, 16 μm or less, or 15 μm or less may be used while maintaining good fine wiring formation properties. hole. The lower limit of the top diameter of the via hole is not particularly limited, but may be usually 3 μm or more and 8 μm or more.

The number of via holes formed in the step (C) is not particularly limited and may be appropriately determined in accordance with the design of the circuit board. The top diameters of the plurality of via holes formed may be the same or different. Further, it is not necessary that all of the via holes formed in the step (C) have a top diameter of 40 μm or less. It can be formed by combining via holes having a top diameter of more than 40 μm in accordance with the design of the circuit substrate.

In the step (C), examples of the laser light source include a carbon dioxide laser, a YAG laser, a UV-YAG laser, a YVO ₄ laser, a YLF laser, and an excimer laser. The appropriate laser source can be used according to the absorption characteristics of the plastic film support and the insulating layer.

The irradiation condition of the laser is not particularly limited as long as it can form a via hole having a small diameter, and can be appropriately determined depending on the type of the laser light source, the thickness and type of the plastic film support and the insulating layer, and the like. Hereinafter, the irradiation conditions when a carbon dioxide laser is used as a laser light source are exemplified. When a carbon dioxide laser is used as the laser light source, laser light having a wavelength of 9.3 μm to 10.6 μm is generally used. The number of shots also depends on the depth of the via hole to be formed and the diameter of the top, but is usually selected in the range of 1 to 10 shots. From the viewpoint of increasing the processing speed and increasing the productivity of the circuit substrate, the fewer the number of shots, the better, preferably the range of 1 to 5 shots, and more preferably the range of 1 to 3 shots. Furthermore, when the number of shots is 2 shots or more, the laser light can be irradiated in any of the burst mode and the loop mode. The energy of the laser light also depends on the number of shots, the depth of the via hole, and the thickness of the plastic film support, but is preferably set to be 0.2 mJ or more, more preferably 0.3 mJ or more, and particularly preferably 0.4 mJ or more. The upper limit of the energy of the laser light is preferably 20 mJ or less, more preferably 15 mJ or less, and particularly preferably 10 mJ or less.

Step (C) can be carried out using a commercially available laser device. As a commercially available laser device, "LC-2E21B/1C" (carbon dioxide laser device) manufactured by Hitachi VIA Machinery Co., Ltd., and "605GTWIII (-P)" (carbon dioxide laser) manufactured by Mitsubishi Electric Corporation. Device), "MODEL5330xi" and "MODEL5335" manufactured by ESI Corporation (UV-YAG laser) Device) and so on.

<Step (D)>

In the step (D), desmear treatment is performed.

In the inside of the via hole formed in the step (C) (especially at the bottom of the via hole), a resin residue (slag) is generally attached. Such a slag is a cause of poor electrical connection between the layers, and a step of removing the slag (de-slag treatment) is carried out in the step (D).

In the method of manufacturing a circuit board of the present invention, the desmear treatment is performed in a state in which the plastic film support is adhered to the insulating layer. Unlike the conventional technique of performing the desmear treatment after peeling off the support, since the surface of the insulating layer is protected by the plastic film support, the surface of the insulating layer is not roughened, and the slag inside the via hole can be removed. Moreover, since the surface of the insulating layer is not subject to damage, a wide range of desmear treatment methods and desmear treatment conditions can be employed. By the way, as a resin composition for forming an insulating layer, a resin composition (for example, a resin composition containing an active ester-based curing agent) which is attributed to a resin residue (slag) which is difficult to remove in the desmear treatment is used. The thickness of the surface of the insulating layer is not increased, and the dross can be effectively removed.

When the desmear treatment is performed in a state in which the plastic film support is adhered to the insulating layer, the large thickness region occurring around the opening of the via hole is a problem, but by using the above specific step (B) According to the method of the present invention, the size of a region having a large thickness occurring around the opening of the via hole can be reduced.

In the step (D), the desmear treatment system is not particularly limited, and It is carried out by various methods well known. The desmear treatment can be carried out, for example, by dry desmear treatment, wet desmear treatment, or a combination thereof.

As the dry desmearing treatment, for example, a desmear treatment using a plasma or the like can be mentioned. Regarding the desmear treatment using the plasma, it is known that the surface of the insulating layer due to the plasma is denatured, and the adhesion strength between the insulating layer and the conductor layer is easily lowered, but the plastic film support is attached to the insulating layer. In the method of the present invention for performing desmear treatment, the desmear treatment can be advantageously carried out without surface denaturation of the insulating layer.

The desmear treatment using plasma can be carried out using a commercially available plasma desmear treatment device. Among the commercially available plasma desizing treatment apparatuses, examples of manufacturing applications suitable for a printed wiring board include a microwave plasma device manufactured by NISSIN and a constant piezoelectric device manufactured by Sekisui Chemical Industry Co., Ltd. Slurry etching device, etc.

As the dry desmearing treatment, it is also possible to use a dry blasting treatment in which a polishing material is sprayed from a nozzle to polish the object to be treated. Dry blasting can be carried out using a commercially available dry blasting apparatus. When a water-soluble abrasive is used as the polishing material, the water is washed by the dry blasting treatment, and the abrasive material does not remain inside the via hole, so that the slag can be effectively removed.

As the wet degreasing treatment, for example, a desmear treatment using an oxidizing agent solution or the like can be mentioned. When the sizing agent is used for the desmear treatment, it is preferred to carry out the swelling treatment by the swelling liquid, the oxidation treatment by the oxidizing agent solution, and the neutralization treatment by the neutralizing liquid in this order. Examples of the swelling liquid include "Swelling Dip Securiganth P" manufactured by ATOTECH Japan Co., Ltd., "Swelling Dip Securiganth SBU", and the like. The swelling treatment is preferably carried out by immersing the substrate on which the via holes are formed in the swelling liquid heated to 60 ° C to 80 ° C for 5 minutes to 10 minutes. The oxidizing agent solution is preferably an alkaline permanganic acid aqueous solution, and examples thereof include a solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The oxidation treatment of the oxidizing agent solution is preferably carried out by immersing the swelled substrate in an oxidizing agent solution heated to 60 ° C to 80 ° C for 10 minutes to 30 minutes. For example, "Concentrate Compact CP" manufactured by ATOTECH Japan Co., Ltd., "Dosing Solution Securiganth P", etc., may be mentioned as a commercially available product of the alkaline permanganic acid aqueous solution. The neutralization treatment of the neutralization liquid is preferably carried out by immersing the oxidized substrate in a neutralization liquid at 30 ° C to 50 ° C for 3 minutes to 10 minutes. The neutralization liquid is preferably an acidic aqueous solution, and a commercially available product is, for example, "Reduction Solution Securigand P" manufactured by ATOTECH Japan Co., Ltd.

As the wet desmearing treatment, a wet blasting treatment capable of polishing the object to be processed by spraying the abrasive and the dispersion medium from the nozzle may be used. The wet blasting treatment can be carried out using a commercially available wet blasting apparatus.

When the combined dry desmear treatment and the wet degumming treatment are carried out, the dry degumming treatment may be performed first, or the wet degreasing treatment may be first performed.

The present inventors have found that in the wet desmearing treatment, the size of the region having a large thickness occurring around the opening of the via hole tends to be large, but the method of the present invention using the above specific step (B) Even when the wet desmearing treatment is carried out, the size of a large area of roughness can be advantageously reduced.

From the viewpoint of more enjoying the effects of the present invention, the desmear treatment of the step (D) is preferably a wet desmearing treatment.

<Step (E)>

In the step (E), the plastic film support is peeled off. Thereby, the surface of the insulating layer is exposed.

The peeling of the plastic film support can be manually peeled off or mechanically peeled off by an automatic peeling device.

During the desmear treatment in the step (D), the surface of the insulating layer is protected by the plastic film support, and the surface of the insulating layer exposed in this step has a low thickness (the thickness of the surface of the insulating layer is As described later). Further, according to the method of the present invention, it is possible to advantageously reduce the size of the region having a large thickness which is generated around the opening of the via hole (the value of the length L _r of the region having a large thickness is as described later). Therefore, the surface of the insulating layer exposed in this step is suitable for forming a fine circuit wiring thereon.

<Step (F)>

In the step (F), a conductor layer is formed on the surface of the insulating layer.

The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer contains one or more selected from the group consisting of gold, platinum, palladium, silver, steel, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. metal. The conductor layer may be a single metal layer or an alloy layer, and examples of the alloy layer include alloys of two or more metals selected from the group (for example, nickel ‧ chromium alloy, copper ‧ nickel alloy, and copper ‧ titanium The layer formed by the alloy). Among them, chromium, nickel, titanium, aluminum, zinc, gold, and the like are preferable from the viewpoints of versatility, cost, and ease of pattern formation of the conductor layer. a single metal layer of palladium, silver or copper, or an alloy layer of nickel ‧ chromium alloy, copper ‧ nickel alloy, copper ‧ titanium alloy, more preferably chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper A single metal layer, or an alloy layer of nickel ‧ chrome alloy, particularly preferably a single metal layer of copper.

The conductor layer may have a single layer structure or a multi-layer structure in which two or more layers of a single metal layer or an alloy layer composed of different kinds of metals or alloys are laminated. When the conductor layer has a multi-layered structure, the layer in contact with the insulating layer is preferably a single metal layer of chromium, zinc or titanium, or an alloy layer of nickel ‧ chrome alloy.

The thickness of the conductor layer depends on the design of the desired circuit substrate, but is usually 35 μm or less, preferably 30 μm or less, and particularly preferably 25 μm or less. The lower limit of the thickness of the conductor layer is not particularly limited, but is usually 3 μm or more, and preferably 5 μm or more.

In one embodiment, the step (F) comprises sequentially forming a metal layer by dry plating on the surface of the insulating layer, and forming a conductor layer by wet plating on the surface of the metal layer.

(Hereinafter, such a step will be referred to as "step (F-1)").

In the step (F-1), a metal layer is first formed by dry plating on the surface of the insulating layer.

Examples of the dry plating include chemical vapor deposition (CVD) methods such as vapor deposition, sputtering, ion plating, and laser ablation, and other chemical vapor deposition (CVD) methods such as physical vapor deposition (PVD), thermal CVD, and plasma CVD. Among them, vapor deposition and sputtering are preferred. The metal layer may be formed by combining two types of dry plating.

The thickness of the metal layer is not particularly limited, but is preferably 5 nm to 2 μm, more preferably 10 nm to 1 μm, still more preferably 20 nm to 500 nm. again The metal layer may be a single layer structure or a multi-layer structure. When the metal layer has a multi-layered structure, the thickness of the entire metal layer is preferably in the above range.

In the step (F-1), after the formation of the metal layer, the conductor layer is formed by wet plating on the surface of the metal layer.

A metal layer is used as the plating layer, and wet plating is performed by a semi-additive method to form a conductor layer having a desired pattern. In detail, in the plating layer (metal layer), a mask pattern in which a part of the plating layer is exposed is formed corresponding to the desired wiring pattern. After the conductor layer is formed by electrolytic plating on the exposed plating layer, the mask pattern is removed. Then, by removing unnecessary plating layers by etching or the like, a conductor layer having a desired wiring pattern can be formed.

When a via hole having a small diameter is used, a fine circuit wiring corresponding thereto is formed around the via hole. However, when the size of the region having a large thickness generated around the opening of the via hole is large, it is difficult to remove the plating layer having a large thickness region when etching the unnecessary plating layer during the formation of the wiring pattern. Further, when etching is performed under the condition that the plating layer having a large thickness region can be sufficiently removed, the dissolution pattern of the wiring pattern becomes conspicuous, and it becomes difficult to form fine circuit wiring around the via hole. In this regard, by adopting the method of the present invention in the specific step (B) described above, the size of the region having a large thickness occurring around the opening of the via hole can be remarkably reduced, so that the via hole of the small diameter can be used. Around the periphery, the fine circuit wiring corresponding thereto is formed in a desired wiring pattern. Therefore, the method of manufacturing the circuit board of the present invention significantly contributes to the miniaturization and high density of the circuit wiring.

Furthermore, in the step (F-1), even if the surface of the insulating layer is not The coarsening treatment can also achieve sufficient adhesion strength between the insulating layer and the conductor layer, but the surface of the insulating layer can also be roughened. In this case, the step (F-1) includes, in order, roughening the surface of the insulating layer, dry plating on the surface of the insulating layer to form a metal layer, and wet plating on the surface of the metal layer. A conductor layer is formed.

Examples of the roughening treatment include a dry roughening treatment and a wet roughening treatment, and the roughening treatment can be carried out by combining them.

The dry roughening treatment can be carried out in the same manner as the dry desmearing treatment described previously. Further, the wet roughening treatment can be carried out in the same manner as the wet desmearing treatment described above. When the dry roughening treatment and the wet roughening treatment are combined, the dry roughening treatment may be performed first, or the wet roughening treatment may be first performed. The roughening treatment is aimed at roughening the exposed surface of the insulating layer, and a certain effect is also achieved regarding the removal of the slag inside the via hole. Therefore, even when the step (D) is carried out under mild conditions, the residue of the slag can be prevented.

In another embodiment, the step (F) comprises: roughening the surface of the insulating layer and wet-plating the surface of the insulating layer to form a conductor layer.

(Hereinafter, such a step will be referred to as "step (F-2)").

The roughening treatment is as described above.

In the step (F-2), the surface of the insulating layer is roughened, and then the conductor layer is formed by wet plating on the surface of the insulating layer.

For example, electroless plating and electrolytic plating can be combined by semi-additive method A conductor layer having a desired wiring pattern is formed. According to the method of the present invention capable of reducing the size of a region having a large thickness around the opening of the via hole, a fine circuit corresponding to the desired pattern can be formed around the via hole having a small diameter. Wiring.

From the viewpoint that the surface roughness of the obtained insulating layer is lower and contributes to the miniaturization and high density of the circuit wiring, the step (F) is preferably step (F-1).

[circuit board]

The circuit board manufactured by the method of the present invention is characterized in that it has a via hole having a top diameter of 40 μm or less, and a large-sized region around the opening portion of the via hole has a small size.

In one embodiment, the circuit board of the present invention is characterized in that it comprises an insulating layer and a conductor layer formed on the insulating layer, and a via hole having a top diameter of 40 μm or less is formed in the insulating layer, and a via hole opening on the surface of the insulating layer is formed. The length (L _r ) of the large area around the portion is less than 10 μm.

The insulating layer and the conductor layer are as described above. Further, the appropriate range of the diameter of the top of the via hole formed in the insulating layer is also as described above.

The length (L _r ) of the region having a large thickness around the opening of the via hole is preferably 8 μm or less, more preferably 6 μm or less, and particularly preferably 5 μm from the viewpoint of forming a fine circuit wiring around the via hole. Hereinafter, it is 4 μm or less, 3 μm or less, or 2 μm or less. The lower limit of the length (L _r ) of the large-thickness region is preferably as small as possible, and may be 0 μm, but is usually 0.1 μm or more. Further, the arithmetic mean roughness (Ra) of the region having a large thickness around the opening of the via hole is usually higher than 200 nm.

In the circuit board of the present invention, the line width of the conductor layer (circuit wiring) provided around the opening of the via hole so as to be electrically connected to the via hole is preferably 40 μm or less, more preferably 30 μm or less, and particularly preferably 20 μm or less. . In the circuit board of the present invention having a small thickness and a large area around the opening of the via hole, a conductor layer having a smaller line width can be formed around the opening of the via hole. In the circuit board of the present invention, the line width of the conductor layer provided around the opening of the via hole so as to be electrically connected to the via hole can be as small as 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, or 8 μm or less. , 6 μm or less or 4 μm or less. The lower limit of the line width is not particularly limited, but may be usually 1 μm or more.

As described above, the circuit board formed by the method of the present invention is characterized in that the surface roughness of the insulating layer is low. For example, the arithmetic mean roughness (Ra) and the root mean square roughness (Rq) of the surface of the insulating layer are as follows. Further, the values of Ra and Rq below are values measured in a certain region having a sufficient distance (preferably 100 μm or more) from the opening end portion of the via hole when the influence of the large thickness region is negligible. .

In the circuit board of the present invention, the arithmetic mean roughness (Ra) of the surface of the insulating layer is preferably 200 nm or less, more preferably 180 nm or less, still more preferably 160 nm or less, still more preferably 140 nm or less, and particularly preferably 100 nm or less. 90 nm or less, 80 nm or less, 70 nm or less, or 60 nm or less. The lower limit of the Ra value is not particularly limited, but may be 0.5 nm or more and 1 nm or more in order to stabilize the adhesion strength to the conductor layer. Again, insulation The root mean square roughness (Rq) of the surface of the layer is preferably 250 nm or less, more preferably 200 nm or less, still more preferably 150 nm or less, and still more preferably 130 nm or less, 110 nm or less, or 90 nm or less. The lower limit of the Rq value is not particularly limited, but may be 10 nm or more and 30 nm or more in order to stabilize the adhesion strength to the conductor layer. The arithmetic mean roughness (Ra) and the root mean square roughness (Rq) of the surface of the insulating layer can be measured using a non-contact type surface roughness meter. A specific example of the non-contact type surface roughness meter is "WYKO NT3300" manufactured by VEECO Instruments.

The circuit board manufactured by the method of the present invention has a sufficient adhesion strength (peeling strength) on the surface of the insulating layer, although the thickness of the surface of the insulating layer is as low as described above, that is, preferably 0.4 kgf/cm or more. More preferably, it is 0.45 kgf/cm or more, and particularly preferably 0.5 kgf/cm or more, and more preferably a conductor layer of 0.54 kgf/cm or more. The higher the adhesion strength, the better, but generally 1.5 kgf/cm is the upper limit. The peel strength of the insulating layer and the conductor layer can be measured in accordance with JIS C6481.

[semiconductor device]

A semiconductor device can be manufactured using the circuit substrate manufactured by the method of the present invention.

Examples of the semiconductor device include various semiconductor devices for use in electrical products (for example, computers, mobile phones, digital cameras, and televisions) and vehicles (for example, locomotives, automobiles, electric cars, ships, and aircrafts).

[Examples]

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by the examples. In the following description, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise stated.

First, various measurement methods and evaluation methods will be described.

[Measurement ‧ Preparation of sample for evaluation] (1) Base processing of the inner layer circuit substrate

A glass cloth substrate having an inner layer circuit is formed on both sides of a double-sided laminate (copper foil thickness: 18 μm, substrate thickness: 0.3 mm, size: 500 mm × 500 mm, "R5715ES" manufactured by Panasonic Co., Ltd.), and immersed in MEC (shares) In the "CZ8100", 1 μm was etched, and the copper surface was roughened.

(2) Lamination of resin sheets with support

A protective film of a resin sheet (size: 494 mm × 494 mm) with a support prepared in the following production example was peeled off, and a batch type vacuum pressure laminator (Nichigo-Morton Co., Ltd. 2-stage build-up laminator) was used. CVP700) is laminated on both sides of the inner layer circuit board such that the resin composition layer is in contact with the inner layer circuit board. The laminate was subjected to a pressure reduction for 30 seconds to bring the gas pressure to 13 hPa or less, and then was pressure-bonded at 100 ° C and a pressure of 0.74 MPa for 30 seconds. Next, hot pressing was performed for 60 seconds at 100 ° C and a pressure of 0.5 MPa.

(3) Hardening of the resin composition layer

The resin sheet to which the support was laminated was heated at 100 ° C for 30 minutes, and then heated at 170 ° C for 30 minutes to thermally cure the resin composition layer to form an insulating layer. The obtained substrate is referred to as "evaluation substrate A".

(4) Formation of via holes

A laser is irradiated from the plastic film support to form a small diameter via hole in the insulating layer. In the first embodiment and the comparative example 1, according to the procedure of the following (A), the second embodiment and the second comparative example are in accordance with the procedure of the following (B), and the third embodiment is in accordance with the procedure of the following (C). In the fourth embodiment, via holes having small diameters were formed in accordance with the procedure of the following (D).

(A) Using a CO ₂ laser processing machine "605GTWIII (-P)" manufactured by Mitsubishi Electric Corporation, a laser was irradiated from the plastic film support, and a via hole having a top diameter (diameter) of 30 μm was formed in the insulating layer. The irradiation conditions of the laser are a mask diameter of 1 mm, a pulse width of 16 μs, an energy of 0.2 mJ/shot, a shot number of 2, and a burst mode (10 kHz).

(B) A laser was irradiated from the plastic film support using a UV-YAG laser processing machine "MODEL5330xi" manufactured by ESI Corporation, and a via hole having a top diameter (diameter) of 20 μm was formed in the insulating layer. The irradiation conditions of the laser were Z offset 0.0 mm, power 0.40 W, Bite Size: 1.15 μm, Velocity: 69 mm/sec, Rep Rate: 60 kHz, Repetition: 3, circle/punch mode.

(C) Using UV-YAG laser processing machine manufactured by ESI "MODEL5330xi", which irradiates a laser from a plastic film support, and forms a via hole having a top diameter (diameter) of 15 μm in the insulating layer. The irradiation conditions of the laser are Z offset 0.0 mm, power 0.40 W, Bite Size: 2.0 μm, Velocity: 120 mm/sec, Rep Rate: 60 kHz, Repetition: 15, circle/punch mode.

(D) Using a CO ₂ laser processing machine "605GTWIII (-P)" manufactured by Mitsubishi Electric Corporation, a laser was irradiated from the plastic film support to form a via hole having a top diameter (diameter) of 12 μm in the insulating layer. The irradiation conditions of the laser are a mask diameter of 0.7 mm, a pulse width of 12 μs, an energy of 0.15 mJ/shot, a shot number of 3, and a circulation mode.

(5) Degumming treatment

After the formation of the via hole, the desmear treatment is performed in a state where the plastic film support is adhered to the insulating layer. Further, as the desmear treatment, the following wet type desmear treatment (Examples 1 to 3, Comparative Examples 1 and 2) and dry desmearing treatment (Example 4) were carried out.

Wet desmear treatment:

The substrate having the via holes formed therein was immersed in a swelling liquid ("Swelling Dip Securigand P" manufactured by Atotech Japan Co., Ltd., an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C for 5 minutes, followed by 80. °C was immersed in an oxidizing agent solution (Concentrate Compact CP, manufactured by ATOTECH Co., Ltd.), an aqueous solution having a potassium permanganate concentration of about 6 mass% and a sodium hydroxide concentration of about 4 mass% for 20 minutes, and finally immersed at 40 ° C. The stain was dried in a neutralizing solution ("Reduction Solution Securigand P" manufactured by ATOTECH Co., Ltd., aqueous sulfuric acid solution) for 5 minutes, and then dried at 80 ° C for 15 minutes.

Dry desmear treatment:

For the substrate on which the via hole was formed, a vacuum plasma etching apparatus (100-E PLASMA SYSTEM, manufactured by Tepla Co., Ltd.) was used, and under the conditions of O ₂ /CF ₄ (mixed gas ratio) = 25/75 and a vacuum of 100 Pa, 5 was carried out. Minute processing.

(6) Peeling of plastic film support

After the desmear treatment, the plastic film support was peeled off in accordance with the procedure described below to expose the surface of the insulating layer. First, at one end of the substrate 4 end after the desmear treatment, a vibrating pen is pressed from the plastic film support to form a peeling portion. The peeling portion was grasped by hand, and the plastic film support was peeled off in a diagonal direction toward the substrate. The obtained substrate is referred to as "evaluation substrate B".

(7) Formation of conductor layer

A conductor layer is formed on the exposed surface of the insulating layer. The conductor layer was formed by a dry method in accordance with the following procedure. The obtained substrate is referred to as "evaluation substrate C". Further, the following dry method corresponds to the above step (F-1).

Dry method:

After heating the evaluation substrate B at 150 ° C for 30 minutes, a titanium layer (thickness: 30 nm) was formed on the insulating layer using a sputtering apparatus ("E-400S" manufactured by Canon-Anelva Co., Ltd.), and a copper layer (thickness: 300 nm) was formed next. ), set the plating layer. Next, an etching resist was formed according to the semi-additive method, and a mask pattern was formed by exposure ‧ development, and then copper sulfate electrolytic plating was performed to form a conductor layer (thickness: 25 μm). After the mask pattern is removed, an unnecessary plating layer (copper etching solution: SAC made by JCU, titanium etching liquid: Rhombus Chemical (W)-WLC-T) is removed by etching to form a conductor pattern. The obtained substrate was annealed by heating at 190 ° C for 60 minutes.

<1. Determination of the adhesion strength between the insulating layer and the plastic film support>

The adhesion strength between the insulating layer and the plastic film support was measured for the evaluation substrate A according to the following procedure. The evaluation substrate A was cut into a size of 30 mm in width and 150 mm in length so as to be elongated in the longitudinal direction (MD direction) of the plastic film support. Next, the slit was introduced by a cutter from the side of the plastic film support body with a width of 15 mm and a length of 100 mm. One end of the plastic film support was peeled off from the insulating layer, and grasped by a jig, and the load at 30 mm of the plastic film support in the vertical direction at a temperature of 50 mm/min at room temperature (23 ° C) was measured to obtain the adhesion strength. . A tensile tester ("AC-50C-SL" manufactured by TSE) was used for the measurement.

<2. Evaluation of peelability of plastic film support>

For the evaluation of the substrate B, the peeling property of the plastic film support was evaluated. View Five sheets of the evaluation substrate B (i.e., all of the 10 sides) were examined to determine whether or not the plastic film support remained. Then, the peelability was evaluated in accordance with the following criteria. In addition, when the evaluation is "X", the evaluation of the following 3. to 6. is not carried out.

Evaluation criteria:

○: The residual of the plastic film support is not visible on all sides.

×: On one or more surfaces, the residue of the plastic film support was observed.

<3. Evaluation of the size of a large area of coarseness>

With respect to the evaluation substrate B, the periphery of the opening of the via hole was observed with a scanning electron microscope (SEM), and the length (L _r ) of the region having a large thickness around the opening of the via hole was measured from the obtained image. The length (L _r ) of the large-thickness region is the difference (r2-r1) between the radius r1 of the opening (inner circle) of the via hole and the radius r2 of the outer edge (outer circle) of the large-diameter region. For 10 via holes, L _{r was} obtained, and the size of the large region of the roughness was evaluated on the basis of the following.

Evaluation criteria:

○: L _{r is} less than 10 μm in all via holes

×: _Lr is 10 μm or more in one or more via holes

<4. Determination of arithmetic mean roughness (Ra) and root mean square roughness (Rq) >

For the evaluation substrate B, a non-contact surface roughness meter ("WYKONT3300" manufactured by VEECO Instruments Co., Ltd.) was used, and the VSI was connected. In the touch mode and the 50-fold lens, the Ra value and the Rq value were obtained from the values obtained in the measurement range of 121 μm × 92 μm. The average value of 10 points which were randomly selected was measured from the opening end portion of the via hole from a region of 100 μm or more.

<5. Measurement of the adhesion strength between the insulating layer and the conductor layer>

The measurement of the peeling strength between the insulating layer and the conductor layer was carried out in accordance with JIS C6481 for the evaluation of the substrate C. Specifically, in the conductor layer of the evaluation substrate D, a slit having a size of 10 mm and a length of 100 mm was introduced, and one end of the substrate was grasped by a jig, and when the thickness was peeled off by 35 mm in the vertical direction at a speed of 50 mm/min at room temperature. The load (kgf/cm) is used to obtain the adhesion strength. A tensile tester ("AC-50C-SL" manufactured by TSE) was used for the measurement.

<6. Evaluation of glue removal property>

For the evaluation substrate B, the periphery of the bottom of the via hole was observed with a scanning electron microscope (SEM), and the maximum image length from the wall surface at the bottom of the via hole was measured from the obtained image. The slag removal property was evaluated according to the following criteria.

Evaluation criteria:

○: The maximum slag length is less than 3μm

×: The maximum slag length is 3 μm or more

<Preparation Example 1> Modulation of Resin Varnish 1

The bisphenol epoxy resin (epoxy equivalent of about 165, "ZX1059" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., 1:1 of bisphenol A and bisphenol F type was heated and dissolved in 20 parts of solvent oil. Mixed product) 5 parts, bi-xyl phenol type epoxy resin (epoxy equivalent: 185, "YX4000HK" manufactured by Mitsubishi Chemical Co., Ltd.) 10 parts, biphenyl type epoxy resin (epoxy equivalent of about 290, Nipponization) 10 parts of "Non-Pharmaceutical Co., Ltd.""NC3000H") and 10 parts of phenoxy resin ("7555BH30" manufactured by Mitsubishi Chemical Corporation, and methyl ethyl ketone (MEK) solution of 30% by mass of solid content). After cooling to room temperature, 12 parts of a naphthol-based curing agent (hydroxyl equivalent 215, "SN-485" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., 60% solid content) was mixed therein, and three were contained therein. A phenol novolac-based hardener (hydroxy equivalent: 125, DIC (manufactured by the company) "LA-7054", solid content 60% MEK solution) 8 parts, hardening accelerator (4-dimethylaminopyridine (DMAP)) , 2 parts by mass of MEK solution of solid content) 4 parts, flame retardant ("HCA-HQ" manufactured by Sanguang Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa- 10-phosphaphenanthrene-10-oxide, average particle size 1 μm) 2 parts, rubber particles ("Staphyloid AC3816N" manufactured by AICA Industries Co., Ltd.) 3 parts, amine-based decane-based coupling agent (Shin-Etsu Chemical Industry Co., Ltd.) "Spherical meteorite ("KS1" manufactured by ADMATECHS) having an average particle diameter of 0.24 μm, and particles of 3 μm or more are removed by classification, and the amount of carbon per unit area is 0.36 mg/m ² . 90 parts were uniformly dispersed by a high-speed rotary disperser to prepare a resin varnish 1.

<Production Example 1> Production of Resin Sheet 1 with Support

As a plastic film support, a PET film (formerly manufactured by Toray Industries Co., Ltd.) "Lumirror T6AM" prepared by a heavy-peeling non-polyoxygen-based release agent ("NSP-4" manufactured by Fujimori Industrial Co., Ltd.) was prepared. ", thickness 25 μm). The resin varnish 1 was applied onto the release surface of the plastic film support by a die coater, and dried at 80 ° C to 110 ° C (average 100 ° C) for 4 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm. Next, on the surface of the resin composition layer which is not bonded to the plastic film support, the polypropylene film which is a protective film ("Alphan MA-411" manufactured by Oji Paper Co., Ltd., thickness 15 μm) A resin sheet 1 with a support was obtained.

<Production Example 2> Production of Resin Sheet 2 with Support

As a plastic film support, a PEN film (Teonex Q83 made by Teijin DuPont Film Co., Ltd.) which has been subjected to release treatment by a heavy release type polyfluorene-containing release agent ("SK-1" manufactured by LINTEC Co., Ltd.) is prepared. , thickness 25μm). The resin varnish 1 was applied onto the release surface of the plastic film support by a die coater, and dried at 80 ° C to 110 ° C (average 100 ° C) for 3 minutes to form a resin composition layer. The thickness of the resin composition layer was 15 μm. Next, on the surface of the resin composition layer which is not bonded to the plastic film support, the polypropylene film which is a protective film ("Alphan MA-411" manufactured by Oji Paper Co., Ltd., thickness 15 μm) A resin sheet 2 with a support was obtained.

<Production Example 3> Production of Resin Sheet 3 with Support

In addition to being used as a plastic film support, a PEN film (Deonex Q83 made by Teijin DuPont Film Co., Ltd.) was released by a heavy-peeling non-polyoxymethane-based release agent ("AL-5" manufactured by LINTEC Co., Ltd.). In the same manner as in Production Example 2, a resin sheet 3 with a support was obtained, except for a thickness of 25 μm.

<Production Example 4> Production of Resin Sheet 4 with Support

As a plastic film support, a PET film ("Lumirror T6AM" manufactured by Toray Co., Ltd.) which has been subjected to release treatment by a non-polyoxyl-type release agent ("AL-5" manufactured by LINTEC Co., Ltd.)) , thickness 50μm). The resin varnish 1 was applied onto a release surface of the plastic film support by a die coater, and dried at 80 ° C to 110 ° C (average 100 ° C) for 2 minutes to form a resin composition layer. The thickness of the resin composition layer was 10 μm. Next, on the surface of the resin composition layer which is not bonded to the plastic film support, the polypropylene film which is a protective film ("Alphan MA-411" manufactured by Oji Paper Co., Ltd., thickness 15 μm) A resin sheet 4 with a support was obtained.

<Production Example 5> Production of Resin Sheet 5 with Support

In addition to the plastic film support, a PET film that has been subjected to release treatment by a heavy-peeling non-polyoxygen-based mold release agent ("NSP-5" manufactured by Fujimori Industrial Co., Ltd.) (Toray Co., Ltd., "Lumirror") A resin having a support was obtained in the same manner as in Production Example 1 except that T6AM was 25 μm thick. Sheet 5.

<Production Example 6> Production of Resin Sheet 6 with Support

In addition to being used as a plastic film support, a PEN film (Teenex Q83 made by Teijin DuPont Film Co., Ltd.) which has been subjected to release treatment by a heavy release type polyfluorene-containing release agent ("6040" manufactured by LINTEC Co., Ltd.), A resin sheet 6 with a support was obtained in the same manner as in Production Example 2 except that the thickness was 25 μm.

<Examples 1 to 4 and Comparative Examples 1, 2>

As shown in Table 2, the resin substrate 1 to 6 with the support was used, and the circuit board was manufactured in accordance with the procedure of "measurement of the sample for evaluation ‧ evaluation". The results of each evaluation are shown in Table 2.

In Comparative Example 1 in which the adhesion strength between the heat-hardened insulating layer and the plastic film support was as high as 19 gf/cm, when the plastic film support was peeled off, the via hole was used as a starting point, and the cut of the plastic film support was confirmed. One part of the plastic film support remains on the surface of the insulating layer (remaining the remaining of the plastic film support on the four sides). In Comparative Example 2 in which the adhesion strength was as low as 1 gf/cm, the size of the region having a large thickness occurring around the opening of the via hole was large.

On the other hand, in Examples 1 to 4 in which the adhesion strength between the heat-hardened insulating layer and the plastic film support was in the range of 2 gf/cm to 18 gf/cm, it was confirmed that the coarseness occurring around the opening of the via hole was remarkably reduced. The size of the large area. In the first to fourth embodiments, it was confirmed that an insulating layer having a low thickness and a high adhesion strength to the conductor layer can be formed, and excellent slag removal property can be achieved.

Claims (13)

A method for manufacturing a circuit board, comprising: (A) a resin sheet comprising a plastic film support and a resin composition layer bonded to the plastic film support, and a resin composition layer and an inner layer a step of laminating the substrate, a step of laminating the inner layer substrate, and (B) a step of thermally hardening the resin composition layer to form an insulating layer, wherein the adhesion strength of the insulating layer to the plastic film support is 2 gf/cm to 18 gf /cm, (C) a step of irradiating a laser from a plastic film support, forming a via hole having a top diameter of 40 μm or less in the insulating layer, (D) performing a desmear treatment step, and (E) peeling the plastic film support And the step of forming a conductor layer on the surface of the insulating layer. The method of claim 1, wherein the desmear treatment of step (D) is a wet desmearing treatment. The method of claim 1, wherein the step (F) comprises sequentially forming a metal layer by dry plating on the surface of the insulating layer, and wet plating on the surface of the metal layer to form a conductor layer. The method of claim 1, wherein the plastic film support system is provided with a plastic film support of the release layer. The method of claim 1, wherein the resin composition layer comprises an epoxy resin, a hardener, and an inorganic filler. The method of claim 5, wherein the average particle diameter of the inorganic filler It is from 0.01 μm to 3 μm. The method of claim 5, wherein the inorganic filler has an average particle diameter of from 0.01 μm to 0.4 μm. The method of claim 5, wherein the content of the inorganic filler in the resin composition layer is from 40% by mass to 95% by mass based on 100% by mass of the nonvolatile component in the resin composition layer. The method of claim 5, wherein the inorganic filler is surface-treated with a surface treatment agent. A circuit substrate manufactured by the method of claim 1. A circuit board comprising a circuit board comprising an insulating layer and a conductor layer formed on the insulating layer, wherein a via hole having a top diameter of 40 μm or less is formed in the insulating layer, and a roughness around the opening of the via hole of the surface of the insulating layer The length of the large area is less than 10 μm. The circuit board of claim 11, wherein the surface of the insulating layer has an arithmetic mean roughness Ra of 200 nm or less. A semiconductor device comprising the circuit substrate according to any one of claims 10 to 12.