KR102304528B1 - Method for producing circuit board - Google Patents

Abstract

[Problem] A technology capable of reducing the dimension of the illuminance band generated around the via hole opening when manufacturing a circuit board having a via hole with a small diameter using a technology that performs desmear treatment while the support is attached to the insulating layer provides
[Solution means] (A) a step of laminating a resin sheet with a support comprising a plastic film support and a resin composition layer to be bonded to the plastic film support on an inner-layer substrate such that the resin composition layer is bonded to the inner-layer substrate, (B ) A step of thermosetting the resin composition layer to form an insulating layer, wherein the adhesive strength between the insulating layer and the plastic film support is 2 gf / cm to 18 gf / cm, (C) laser irradiation from above the plastic film support , a step of forming 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 the plastic film support, and (F) a conductor layer on the surface of the insulating layer The manufacturing method of a circuit board including the process of forming in this order.

Description

Circuit board manufacturing method {METHOD FOR PRODUCING CIRCUIT BOARD}

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

BACKGROUND ART Circuit boards widely used in various electronic devices are required for miniaturization and high density of circuit wiring for miniaturization and high functionality of electronic devices. As a manufacturing technique of a circuit board, the manufacturing method by the build-up system which laminates|stacks an insulating layer and a conductor layer alternately on an inner-layer board is known. In the manufacturing method by the build-up method, the insulating layer is formed by laminating a resin composition layer on an inner substrate using, for example, a resin sheet with a support including a support and a resin composition layer, and thermosetting the resin composition layer. is formed Next, by drilling the formed insulating layer to form a via hole and desmearing, the resin residue (smear) inside the via hole and the surface of the insulating layer are roughened at the same time (for example, Patent Document 1).

Japanese Patent Laid-Open No. 2008-37957

In the manufacturing method by a buildup system, a conductor layer is formed in the surface of an insulating layer after a desmear process. At this time, if the unevenness of the surface of the insulating layer after desmear treatment is large, it will interfere with the miniaturization of circuit wiring. desirable. When this point and the present inventors manufacture a circuit board using the resin sheet with a support body, by performing desmear process in the state which the support body adhered to the insulating layer, it is low illuminance, and close_contact|adherence with a conductor layer It has been found that an insulating layer with high strength can be formed. According to this technique, since the restriction that the surface of the insulating layer is damaged during desmear treatment is greatly alleviated, a wide range of desmear treatment methods and desmear treatment conditions can be adopted, and the composition of the resin composition constituting the insulating layer It also becomes possible to effectively remove a smear irrespective of this.

On the other hand, while it is required to further increase the density of circuit wiring, the via hole tends to have a small diameter. When manufacturing a circuit board having a small-diameter via hole using the above technique of desmearing in a state where the support is attached to the insulating layer, it is easy to form a small-diameter via hole by laser irradiation during drilling. Therefore, as the support, a plastic film support is suitable. However, the present inventors have found that when desmearing is performed in a state in which the plastic film support is attached to the insulating layer, the area around the via hole opening has a greater illuminance than other areas (also referred to as "illuminance band area"). ) was found to occur. Although this illuminance band region is only formed around the via hole opening, when a via hole with a small diameter (especially a top diameter of 40 µm or less on the surface of the insulating layer) is employed, the corresponding fine circuit wiring is routed through the via hole. Since it is formed in the periphery, the influence of the illuminance band region becomes so large that it cannot be ignored. Therefore, when manufacturing a circuit board having a via hole with a small diameter using a technique of desmearing in a state in which a support is attached to the insulating layer, a technique capable of reducing the dimension of the illuminance band generated around the opening of the via hole is not available. it is desired

The object of the present invention is to reduce the dimension of the illuminance band area generated around the via hole opening when manufacturing a circuit board having a via hole with a small diameter using a technique for performing desmear treatment in a state where a support is attached to an insulating layer. It's about providing the technology you can.

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining the said subject, the present inventors discovered that the said subject could be solved by manufacturing a circuit board by the following specific method, and came to complete this invention.

That is, the present invention includes the following contents.

[1] (A) a step of laminating a resin sheet with a support comprising a plastic film support and a resin composition layer to be bonded to the plastic film support on an inner-layer substrate such that the resin composition layer is bonded to the inner-layer substrate;

(B) a step of thermosetting the resin composition layer to form an insulating layer, wherein the adhesive strength between the insulating layer and the plastic film support is 2 gf/cm to 18 gf/cm;

(C) a step of irradiating a laser from above the plastic film support, and forming a via hole with a top diameter of 40 μm or less in the insulating layer;

(D) the process of performing a desmear process,

(E) a step of peeling the plastic film support, and

(F) Step of forming a conductor layer on the surface of the insulating layer

A method of manufacturing a circuit board comprising in this order.

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

[3] The step (F) of [1] or [2],

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 a metal layer

A method comprising in this order.

[4] The method according to any one of [1] to [3], wherein the plastic film support is a plastic film support with a 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 0.01 µm to 3 µm.

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

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

[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 manufactured by the method according to any one of [1] to [9].

[11] A circuit board comprising an insulating layer and a conductor layer formed on the insulating layer,

A via hole having a top diameter of 40 μm or less is formed in the insulating layer,

The circuit board, wherein the length of the illuminance band region around the via hole opening in the insulating layer surface is less than 10 μm.

[12] The circuit board according to [11], wherein the arithmetic mean roughness (Ra) of the surface of the insulating layer is 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 a circuit board having a via hole with a small diameter is manufactured using a desmear process in a state in which a support is attached to the insulating layer, the dimension of the illuminance band region generated around the via hole opening can be reduced. have.

In Fig. 1, (a1) is an SEM photograph showing the surface of the insulating layer around the via hole opening, and (b1) is an enlarged SEM photograph showing the inside of the dotted line in (a1).
In Fig. 2, (a2) is an SEM photograph showing the surface of the insulating layer around the via hole opening, and (b2) is an enlarged SEM photograph showing the inside of the dotted line in (a2).

<Resin sheet with support>

Before explaining in detail the manufacturing method of the circuit board of this invention, the resin sheet with a support body used by the method of this invention is demonstrated.

The resin sheet with a support body used by the method of this invention contains a plastic film support body, and the resin composition layer joined with the said plastic film support body.

(plastic film support)

As the material of the plastic film support, for example, polyester such as polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”), polyethylene naphthalate (hereinafter sometimes abbreviated as “PEN”), polycarbonate ( Hereinafter, it may be abbreviated as "PC"), acryl such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. can Among them, PET, PEN, and polyimide are preferable, and PET and PEN are more preferable. In one suitable embodiment, the plastic film support is a PET film support or a PEN film support.

As will be described later, in the method for manufacturing a circuit board of the present invention, a via hole having a small diameter is formed by irradiating a laser from above the plastic film support. From a viewpoint of being able to form a via hole smoothly by laser irradiation, it is preferable that a plastic film support body can absorb laser energy. For example, since the PEN film support has ultraviolet (UV) absorption, it can be suitably used for via hole formation by UV irradiation.

By containing a laser energy absorptive component in a plastic film support body, you may provide or increase laser energy absorptivity. The laser energy absorbing component is not particularly limited as long as it can absorb the laser used for forming the via hole, and for example, carbon powder, metal compound powder, metal powder, black dye, etc. can be heard A laser energy absorbing component may be used individually by 1 type, and may be used in combination of 2 or more type.

As carbon powder, the powder of carbon black, such as furnace black, channel black, acetylene black, thermal black, anthracene black, graphite powder, and the powder of these mixtures are mentioned, for example. As the metal compound powder, for example, titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, zinc oxide such as manganese dioxide and zinc oxide, silicon dioxide, aluminum oxide , rare earth oxides, cobalt oxides such as cobalt oxide, tin oxides such as tin oxide, tungsten oxides such as tungsten oxide, silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride, barium sulfate, rare earth acid sulfides, and and powders of these mixtures. Examples of the metal powder include silver, aluminum, bismuth, cobalt, copper, iron, magnesium, manganese, molybdenum, nickel, palladium, antimony, silicon, tin, titanium, vanadium, tungsten, zinc, and alloys or mixtures thereof. powder etc. are mentioned. Examples of the black dye include azo (monoazo, disazo, etc.) dyes, azo-methine dyes, anthraquinone dyes quinoline dyes, ketone imine dyes, fluorone dyes, nitro dyes, xanthene dyes, acenaphthene dyes, and quinone dyes. nophthalone dyes, aminoketone dyes, methine dyes, perylene dyes, coumarin dyes, perinone dyes, triphenyl dyes, triallylmethane dyes, phthalocyanine dyes, inclophenol dyes, azine dyes, and mixtures thereof. have. Since black dye improves dispersibility, it is preferable that it is a solvent-soluble black dye. Among them, as the laser energy absorbing component, carbon powder is preferable, and carbon black is particularly preferable from the viewpoints of conversion efficiency of laser energy into heat, versatility, and the like. The upper limit of the average particle diameter of the laser energy absorbing component is preferably 20 µm or less, more preferably 10 µm or less, from the viewpoint of efficiently absorbing laser energy. From the viewpoint of dispersibility, the lower limit of the average particle diameter is preferably 0.001 µm or more, more preferably 0.002 µm. The "average particle diameter" here can be measured by a particle size distribution measuring apparatus and BET method. The BET method is a method in which molecules having a known adsorption occupied area on the surface of powder particles are adsorbed at a temperature of liquid nitrogen, and the specific surface area of the sample is obtained from the amount thereof. An average particle diameter can be computed from the specific surface area calculated|required from the BET method.

The content of the laser energy absorbing component is preferably 0.01% by mass or more, more preferably 0.03% by mass or more, from the viewpoint of smoothly forming via holes when all components constituting the plastic film support are 100% by mass. , More preferably, it is 0.05 mass % or more. The upper limit of the content is preferably 40 mass % or less, more preferably 20 mass % or less, still more preferably 10 mass % or less from the viewpoint of obtaining a plastic film support having good flexibility. In addition, the laser energy absorbing component may be contained in the mold release layer mentioned later.

As a commercial item of a plastic film support body, For example, "Lumiror R56", "Lumiror R80", "Lumiror T6AM" (PET film) manufactured by Toray Co., Ltd., "G2LA" manufactured by Tejin DuPont Film Co., Ltd. (PET film), “Theonex Q83” (PEN film), “Upirex-S” (polyimide film) manufactured by Ubekosan Co., Ltd., “Apical AH” manufactured by Kaneka, “Apical” NPI" (polyimide film) etc. are mentioned.

A plastic film support body may give a mat treatment and corona treatment to the surface to join with the resin composition layer.

Since it is easy to adjust the adhesion strength between the insulating layer and the plastic film support to a desired range in the step (B) to be described later, as the plastic film support, the plastic film with a release layer has a release layer on the surface to be bonded to the resin composition layer. A support is suitable. As a mold release agent used for a mold release layer, non-silicone type mold release agents, such as an alkyd resin, a melamine resin, an olefin resin, and a urethane resin, and a silicone type mold release agent are mentioned, for example. A mold release agent may be used individually by 1 type, and may be used in combination of 2 or more type. Especially, since it shows high wettability with respect to a resin varnish when producing a resin sheet with a support body, and the contact state with a resin composition layer tends to become uniform over the whole surface, a release layer containing a non-silicone type release agent is preferable. and a release layer containing an alkyd resin and/or an olefin resin is more preferable.

The release agent, depending on the type of its constituent components, is a so-called light-peelable release agent with a low peel strength, a so-called middle-peel type release agent with a high peel strength, a light-peelable release agent and a heavy-peel type release agent. It can be classified as a release agent of the so-called jungbak release type, which shows the medium peel strength of the release agent of ) is preferred. Although it also varies depending on the composition of the resin composition layer for forming the insulating layer, the lamination conditions in the step (A), the thermosetting conditions in the step (B), etc., as a mold release agent, the initial adhesion strength is preferably 100 (mN/ 20 mm) or more, more preferably 300 (mN/20 mm) or more, still more preferably 500 (mN/20 mm) or more, 700 (mN/20 mm) or more, 800 (mN/20 mm) or more, 900 (mN/20 mm) or more. You may use more than or 1000 (mN/20mm) or more of mold release agents. Although the upper limit of the initial adhesion strength is not particularly limited, from the viewpoint of smoothly peeling the plastic film support in the step (E), it is usually 8000 (mN/20 mm) or less, 7500 (mN/20 mm) or less, etc. have. The initial adhesion strength was determined by attaching an acrylic adhesive tape (“31B” manufactured by Nitto Denko Co., Ltd.) to the surface treated with a release agent using a 2 kg roller, leaving it for 30 minutes, and peeling one end of the acrylic adhesive tape. It can be calculated|required by measuring and calculating|requiring the load (mN/20mm) at the time of holding with a gripping tool and removing under the conditions of a 30 cm/min speed|rate, and 180 degree peeling angle at room temperature. The measurement may be performed using, for example, a tensile tester such as “AC-50C-SL” manufactured by TSE Corporation.

As a commercial item of a mold release agent, For example, "X" (silicone-containing alkyd resin mold release agent; 490 mN/20 mm), "SK-1" (silicone-containing alkyd resin mold release agent; 1250 mN/20 mm) manufactured by Lintec Co., Ltd., "AL-" 5" (non-silicone/alkyd resin release agent; 1480 mN/20 mm), "6050" (non-silicone/alkyd resin release agent; 2400 mN/20 mm), "6051" (non-silicone/alkyd resin release agent; 2800 mN/20 mm), "6052" (Non-silicone alkyd resin type mold release agent; 4000 mN/20 mm) etc. are mentioned (The value of the adhesion strength of an initial stage is shown in parentheses). As a commercial item of a mold release agent, "AL-7" (non-silicone alkyd resin type mold release agent; heavy release type) manufactured by Lintec Co., Ltd., "NSP-4" (non-silicone/ An alkyd resin type mold release agent; heavy release type|mold (heavy 剝離型), etc. are mentioned.

Although the thickness of a plastic film support body is not specifically limited, The range of 10 micrometers - 100 micrometers is preferable, and the range of 15 micrometers - 75 micrometers is more preferable. In particular, from the viewpoint of facilitating formation of small-diameter vias, 20 µm to 50 µm are more preferable. Moreover, when a plastic film support body is a plastic film support body with a mold release layer, it is preferable that the thickness of the whole plastic film support body with a mold release layer is the said range.

(resin composition layer)

The resin composition used for the resin composition layer is not particularly limited as long as the cured product thereof has sufficient hardness and insulating properties and a desired adhesion strength with the plastic film support. For example, a resin composition including an epoxy resin, a curing agent, and an inorganic filler may 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 type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolak type Epoxy resin, phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, Cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, butadiene structure epoxy resin, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, naph A thylene ether type epoxy resin, a trimethylol type epoxy resin, etc. are mentioned. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type.

It is preferable that an epoxy resin contains the epoxy resin which has two or more epoxy groups in 1 molecule. When the nonvolatile component of an epoxy resin is 100 mass %, it is preferable that at least 50 mass % or more is an epoxy resin which has two or more epoxy groups in 1 molecule. Among them, an epoxy resin having two or more epoxy groups in one molecule and liquid at a temperature of 20°C (hereinafter referred to as “liquid epoxy resin”), and three or more epoxy groups in one molecule, and solid epoxy at a temperature of 20°C It is preferable to contain resin (henceforth "solid epoxy resin"). As the epoxy resin, a resin composition having excellent flexibility can be obtained by using a liquid epoxy resin and a solid epoxy resin together. Moreover, the breaking strength of the insulating layer formed by hardening|curing a resin composition also improves.

As the liquid epoxy resin, bisphenol A epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, phenol novolak type epoxy resin, and epoxy resin having a butadiene structure are preferable, and bisphenol A A type epoxy resin, a bisphenol F type epoxy resin, and a naphthalene type epoxy resin are more preferable. As a specific example of a liquid epoxy resin, "HP4032", "HP4032H", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC Corporation, "jER828EL" (bisphenol A type) manufactured by Mitsubishi Chemical Co., Ltd. Epoxy resin), "jER807" (bisphenol F-type epoxy resin), "jER152" (phenol novolak-type epoxy resin), "ZX1059" (bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Shin-Nittetsu Chemical Co., Ltd. Epoxy resin mixture), "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase Chemutex Co., Ltd., "PB-3600" manufactured by Daiser Chemicals Co., Ltd. (having a butadiene structure) epoxy resin). These may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the solid-state epoxy resin include a naphthalene-type tetrafunctional epoxy resin, a cresol novolak-type epoxy resin, a dicyclopentadiene-type epoxy resin, a trisphenol epoxy resin, a naphthol-type epoxy resin, a biphenyl-type epoxy resin, a naphthylene ether-type epoxy resin, Anthracene-type epoxy resins are preferable, and naphthalene-type tetrafunctional epoxy resins, naphthol-type epoxy resins, and biphenyl-type epoxy resins are more preferable. As a specific example of a solid-state epoxy resin, "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin) manufactured by DIC Corporation, "N-690" (cresol novolak type epoxy resin), "N- 695" (cresol novolak type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "EXA7311", "EXA7311-G3", "EXA7311-G4", "EXA7311-G4S", "HP6000" ' (naphthylene ether type epoxy resin), "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "NC7000L" (naphthol novolak type epoxy resin), "NC3000H", "NC3000" , "NC3000L", "NC3100" (biphenyl type epoxy resin), "ESN475V" (naphthol type epoxy resin) manufactured by Shin-Nittetsu Chemical Co., Ltd., "ESN485V" (naphthol novolak type epoxy resin), Mitsubishika "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin) manufactured by Kaku Co., Ltd., manufactured by Osaka Gas Chemicals Co., Ltd. "PG-100", "CG-500" of Mitsubishi Chemical Co., Ltd. "YL7800" (fluorene type epoxy resin), etc. are mentioned.

As an epoxy resin, when using a liquid epoxy resin and a solid epoxy resin together, these ratio (liquid epoxy resin:solid epoxy resin) is mass ratio, and the range of 1:0.1 - 1:6 is preferable. By setting the ratio of the liquid epoxy resin to the solid epoxy resin within this range, i) it is possible to bring about adequate adhesion when used in the form of a resin sheet, and ii) to obtain sufficient flexibility when used in the form of a resin sheet. and handling properties are improved, and effects such as iii) being able to obtain a cured product having sufficient breaking strength can be obtained. From the viewpoint of the effects of i) to iii) above, the amount ratio of the liquid epoxy resin and the solid epoxy resin (liquid epoxy resin:solid epoxy resin) is, in terms of mass ratio, more preferably in the range of 1:0.3 to 1:5, 1 The range of :0.6 to 1:4.5 is more preferable.

Content of the epoxy resin in a resin composition becomes like this. Preferably it is 3 mass % - 40 mass %, More preferably, it is 5 mass % - 35 mass %, More preferably, they are 10 mass % - 30 mass %.

In this invention, unless otherwise specified, content of each component in a resin composition is a value when the non-volatile component in a resin composition is 100 mass %.

The epoxy equivalent of an epoxy resin becomes like this. Preferably it is 50-3000, More preferably, it is 80-2000, More preferably, it is 110-1000. By being in this range, the crosslinking density of hardened|cured material becomes sufficient and the insulating layer with small surface roughness can be formed. In addition, an epoxy equivalent can be measured according to JISK7236, It is the mass of resin containing 1 equivalent of an epoxy group.

The weight average molecular weight of an epoxy resin becomes like this. Preferably it is 100-5000, More preferably, it is 250-3000, More preferably, it is 400-1500. Here, the weight average molecular weight of an epoxy resin is the weight average molecular weight of polystyrene conversion measured by the 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, a benzoxazine-based curing agent, and a cyanate ester-based curing agent. A hardening|curing agent may be used individually by 1 type, and may be used in combination of 2 or more type.

As the phenol-based curing agent and the naphthol-based curing agent, from the viewpoint of heat resistance and water resistance, a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolak structure is preferable. Further, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenolic curing agent or a nitrogen-containing naphthol-based curing agent is preferable, and a triazine skeleton-containing phenolic curing agent or a triazine skeleton-containing naphthol-based curing agent is more preferable. Among them, a triazine skeleton-containing phenol novolak resin is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion strength with the conductor layer. These may be used individually by 1 type, and may be used in combination of 2 or more type.

As a specific example of a phenol type hardening|curing agent and a naphthol type hardening|curing agent, For example, Meiwakasei Co., Ltd. product "MEH-7700", "MEH-7810", "MEH-7851", Nihon Kayaku Co., Ltd. product " NHN", "CBN", "GPH", manufactured by Toto Kasei Co., Ltd. "SN-170", "SN-180", "SN-190", "SN-475", "SN-485", "SN" -495", "SN-375", "SN-395", "LA-7052" manufactured by DIC Corporation, "LA-7054", "LA-3018", "LA-1356", etc. are mentioned. .

An active ester type hardening|curing agent is also preferable from a viewpoint of raising the adhesive strength with a conductor layer. Although there is no restriction|limiting in particular as an active ester-type hardening|curing agent, Generally, ester groups with high reaction activity, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and heterocyclic hydroxy compound esters, are two per molecule. The compounds having the above are preferably used. It is preferable that the said active ester type hardening|curing agent is obtained by the condensation reaction of a carboxylic acid compound and/or a thiocarboxylic acid compound, and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester curing agent obtained from a carboxylic acid compound, a phenol compound and/or a naphthol compound is more preferable. 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 naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, dicyclopentadiene type diphenol compound, phenol novolac, etc. are mentioned. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol to one molecule of dicyclopentadiene.

Examples of the active ester curing agent include 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 product of phenol novolac, and a benzoyl product of phenol novolac. The active ester compound containing is preferable, and among these, the active ester compound containing the naphthalene structure and the active ester compound containing the dicyclopentadiene type diphenol structure are more preferable. These may be used individually by 1 type, and may be used in combination of 2 or more type. In addition, "dicyclopentadiene type diphenol structure" represents the divalent structural unit which consists of phenylene-dicyclopentalene-phenyl.

Commercially available active ester curing agents are active ester compounds containing a dicyclopentadiene type diphenol structure, such as "EXB9451", "EXB9460", "EXB9460S", and "HPC-8000-65T" (manufactured by DIC Corporation). , "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated product of phenol novolac, phenol "YLH1026" (made by Mitsubishi Chemical Co., Ltd.) etc. are mentioned as an active ester compound containing the benzoyl compound of novolak.

As a specific example of a benzoxazine type hardening|curing agent, "HFB2006M" by Showa Kobunshi Co., Ltd., "P-d" by Shikoku Chemical Co., Ltd., and "F-a" are mentioned.

Although it does not specifically limit as a cyanate ester type hardening|curing agent, For example, a novolak type (phenol novolak type, alkylphenol novolak type, etc.) cyanate ester type hardening|curing agent, a dicyclopentadiene type|mold cyanate ester type hardening|curing agent, bisphenol Type (bisphenol A type, bisphenol F type, bisphenol S type, etc.) cyanate ester type hardening|curing agent, the prepolymer etc. which these were partially triazined are mentioned. Specific examples include bisphenol A dicyanate, polyphenol cyanate (oligo (3-methylene-1,5-phenylene cyanate)), 4,4'-methylenebis (2,6-dimethylphenyl cyanate), 4 ,4'-ethylidenediphenyldicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis (4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl)thioether, and Bifunctional cyanate resins, such as bis (4-cyanate phenyl) ether, polyfunctional cyanate resin induced|guided|derived from phenol novolak, cresol novolak, etc., the prepolymer etc. which these cyanate resin were triazine-ized in part are mentioned. As a commercial item of a cyanate ester type hardening|curing agent, "PT30" and "PT60" (all are phenol novolak-type polyfunctional cyanate ester resin) manufactured by Ronza Japan Co., Ltd., and "BA230" (part or all of bisphenol A dicyanate) prepolymer) etc. which were triazine-formed and became a trimer are mentioned.

The amount ratio of the epoxy resin and the curing agent is from the viewpoint of improving the mechanical strength and water resistance of the obtained insulating layer, [the total number of epoxy groups in the epoxy resin]: [the total number of reactive groups of the curing agent], The range of :0.2 to 1:2 is preferable, the range of 1:0.3 to 1:1.5 is more preferable, and the range of 1:0.4 to 1:1 is still more preferable. Here, a reactive group of a hardening|curing agent is an active hydroxyl group, an active ester group, etc., and it changes with the kind of hardening|curing agent. In addition, the total number of epoxy groups of the epoxy resin is a value obtained by dividing the solid content mass of each epoxy resin by the epoxy equivalent for all epoxy resins, and the total number of reactive groups of the curing agent is the solid content mass of each curing agent equal to the reactor equivalent. The value divided by , is the sum of all curing agents.

-Inorganic filling material-

Although it does not specifically limit as an inorganic filler, For example, Silica, alumina, glass, cordierite, silicon oxide, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide , boron nitride, aluminum nitride, manganese nitride, aluminum borate, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. can Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica is particularly suitable. Moreover, as a silica, spherical silica is preferable. An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more type. As a commercially available spherical fused silica, "SOC2" and "SOC1" by Adomatex Co., Ltd. are mentioned, for example.

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, from the viewpoint of obtaining an insulating layer on which fine circuit wiring can be formed, and 0.5 ㎛ or less, 0.4 ㎛ or less, or 0.3 ㎛ or less is even more preferable. 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 an appropriate viscosity and good handleability when forming a resin varnish using the resin composition. and more preferably 0.05 µm or more, still more preferably 0.07 µm or more, and particularly preferably 0.1 µm or more. The average particle diameter of the inorganic filler can be measured by a laser diffraction/scattering method based on the Mie scattering theory. Specifically, it can measure by creating the particle size distribution of an inorganic filler on a volume basis with a laser diffraction type particle size distribution measuring apparatus, and making the median diameter into an average particle diameter. As a measurement sample, what disperse|distributed the inorganic filler in water by ultrasonic wave can be used preferably. As a laser diffraction type particle size distribution measuring apparatus, "LA-500", "LA-750", "LA-950", etc. manufactured by Horiba Corporation can be used.

From the viewpoint of further reducing the size of the roughness band region around the via hole opening, it is preferable to use an inorganic filler from which coarse particles have been removed by classification. In one embodiment, it is preferable to use the inorganic filler from which the particle|grains of particle diameter 10 micrometers or more were removed by classification, and it is more preferable to use the inorganic filler from which the particle|grains of particle diameter 5 micrometers or more were removed by classification, It is more preferable to use an inorganic filler from which particles having a particle diameter of 3 μm or more have been removed.

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

The inorganic filler is preferably surface-treated with a surface treatment agent from the viewpoint of improving dispersibility and moisture resistance, and from the viewpoint of further reducing the dimension of the roughness band region around the via hole opening. Examples of the surface treatment agent include an aminosilane-based coupling agent, an epoxysilane-based coupling agent, a mercaptosilane-based coupling agent, a silane-based coupling agent, an organosilazane compound, and a titanate-based coupling agent. A surface treating agent may be used individually by 1 type, and may be used in combination of 2 or more type. As a commercial item of a surface treatment agent, Shin-Etsu Chemical Co., Ltd. product "KBM403" (3-glycidoxypropyl trimethoxysilane), Shin-Etsu Chemical Co., Ltd. product "KBM803" (3-mercapto) is, for example, Propyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM573" (N-phenyl-3-aminopropyltri methoxysilane), Shin-Etsu Chemical Co., Ltd. product "SZ-31" (hexamethyldisilazane), etc. are mentioned.

After the surface treatment of the inorganic filler, the amount of carbon per unit surface area bonded to the surface of the inorganic filler is preferably 0.05 mg/m2 or more, more preferably 0.08 mg/m2 or more, still more preferably 0.11 mg/m2 or more. or more, even more preferably 0.14 mg/m2 or more, particularly preferably 0.17 mg/m2 or more, 0.20 mg/m2 or more, 0.23 mg/m2 or more, or 0.26 mg/m2 or more. The upper limit of the amount of carbon is preferably 1.00 mg/m2 or less, more preferably 0.75 mg/m2 or less, still more preferably 0.70 mg/m2 or less, still more preferably 0.65 mg/m2 or less, 0.60 mg/m2 or less. m 2 or less, 0.55 mg/m 2 or less, and 0.50 mg/m 2 or less.

The amount of carbon per unit surface area couple|bonded with the surface of an inorganic filler is computable with the following procedure. The inorganic filler after surface treatment is ultrasonically cleaned by adding a sufficient amount of methyl ethyl ketone (MEK) as a solvent. After removing the supernatant and drying the solid content, the amount of carbon bonded to the surface of the inorganic filler is measured using a carbon analyzer. By dividing the obtained carbon amount by the specific surface area of an inorganic filler, the carbon amount per unit surface area couple|bonded with the inorganic filler is computed. As a carbon analyzer, "EMIA-320V" by Horibase Corporation, etc. are mentioned, for example.

The content of the inorganic filler in the resin composition is preferably 40 mass % or more from the viewpoint of reducing the thermal expansion coefficient of the insulating layer and preventing the occurrence of cracks and circuit deformation due to the difference in thermal expansion between the insulating layer and the conductor layer, 50 Mass % or more is more preferable, and 60 mass % or more is still more preferable. When an insulating layer is formed using the resin composition with high inorganic filler content, although the adhesive strength of an insulating layer and a conductor layer may fall, according to the manufacturing method of the circuit board of this invention, the resin composition with high inorganic filler content Even when using , sufficient adhesion strength between the insulating layer and the conductor layer can be realized. In the manufacturing method of the circuit board of this invention, content of the inorganic filler in a resin composition can further be raised, without reducing the adhesive strength of an insulating layer and a conductor layer. For example, you may raise content of the inorganic filler in a resin composition to 62 mass % or more, 64 mass % or more, 66 mass % or more, 68 mass % or more, or 70 mass % or more.

From a viewpoint of the mechanical strength of an insulating layer, 95 mass % or less is preferable, as for the upper limit of content of an inorganic filler, 90 mass % or less is more preferable, 85 mass % or less is still more preferable.

In one Embodiment, the resin composition used for a resin composition layer contains the above-mentioned epoxy resin, a hardening|curing agent, and an inorganic filler. Among them, the resin composition is a mixture of a liquid epoxy resin and a solid epoxy resin as an epoxy resin (the mass ratio of the liquid epoxy resin: the solid epoxy resin is preferably 1:0.1 to 1:6, more preferably 1:0.3 to 1: 5, more preferably 1:0.6 to 1:4.5), as a curing agent, at least one selected from the group consisting of a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, and a cyanate ester-based curing agent, as an inorganic filler It is preferable to contain silica, respectively. Also regarding the resin composition layer comprising these specific components in combination, suitable contents of the epoxy resin, the curing agent, and the inorganic filler are as described above, but among them, the content of the epoxy resin is 5% by mass to 35% by mass, and the content of the inorganic filler It is preferable that they are this 40 mass % - 95 mass %, and it is more preferable that content of an epoxy resin is 10 mass % - 30 mass %, and content of an inorganic filler is 50 mass % - 90 mass %. With regard to the content of the curing agent, it is preferable to contain it so that the ratio of the total number of epoxy groups in the epoxy resin to the total number of reactive groups of the curing agent is 1:0.2 to 1:2, and 1:0.3 to 1:1.5. It is more preferable, and it is more preferable to contain it so that it may become 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, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene. Ether resin, polycarbonate resin, polyether ether ketone resin, and polyester resin are mentioned. A thermoplastic resin may be used individually by 1 type, or may be used in combination of 2 or more type.

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

Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene. and phenoxy resins having at least one skeleton selected from the group consisting of skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. Any functional group, such as a phenolic hydroxyl group and an epoxy group, may be sufficient as the terminal of a phenoxy resin. A phenoxy resin may be used individually by 1 type, or may be used in combination of 2 or more type. Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resins) manufactured by Mitsubishi Chemical Co., Ltd., "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" ( bisphenol acetophenone skeleton-containing phenoxy resin), and in addition, "FX280" and "FX293" manufactured by Toto Chemical Co., Ltd., "YL7553", "YL6794", "YL7213" manufactured by Mitsubishi Chemical Co., Ltd. ', "YL7290", "YL7482", etc. are mentioned.

As a specific example of polyvinyl acetal resin, Denki Chemical Co., Ltd. TELEPHONE Butyral 4000-2, 5000-A, 6000-C, 6000-EP, Sekisui Chemical Co., Ltd. S-Rec BH series, BX series, KS series, BL series, BM series, etc. are mentioned.

As a specific example of polyimide resin, "Ricacoat SN20" and "Ricacoat PN20" by Shin Nippon Rica Co., Ltd. are mentioned. As a specific example of the polyimide resin, furthermore, a linear polyimide obtained by reacting a difunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (the one described in Japanese Patent Application Laid-Open No. 2006-37083), containing a polysiloxane skeleton Modified polyimides, such as polyimide (thing described in Unexamined-Japanese-Patent No. 2002-12667 and Unexamined-Japanese-Patent No. 2000-319386), are mentioned.

As a specific example of polyamideimide resin, "Viromax HR11NN" and "Viromax HR16NN" by Toyobo Seki Co., Ltd. are mentioned. Specific examples of the polyamideimide resin include modified polyamideimides such as Hitachi Chemical Co., Ltd. polysiloxane skeleton-containing polyamideimide "KS9100" and "KS9300".

As a specific example of polyether sulfone resin, Sumitomo Chemical Co., Ltd. product "PES5003P" etc. are mentioned.

As a specific example of polysulfone resin, the polysulfone "P1700", "P3500" of Solvay Advansto Formaz Co., Ltd. product, etc. are mentioned.

Content of the thermoplastic resin in a resin composition becomes like this. Preferably it is 0.1 mass % - 20 mass %, More preferably, it is 0.5 mass % - 10 mass %, More preferably, they are 1 mass % - 5 mass %.

-curing accelerator-

Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, and guanidine-based curing accelerators, and phosphorus-based curing accelerators, amine-based curing accelerators and imidazole-based curing accelerators are preferred. . A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type. When content of a hardening accelerator makes the sum total of an epoxy resin and the nonvolatile component of a hardening|curing agent 100 mass %, it is preferable to use it in 0.05 mass % - 3 mass %.

-Flame retardant-

Examples of the flame retardant include an organic phosphorus flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a silicone flame retardant, and a metal hydroxide. A flame retardant may be used individually by 1 type, or may be used in combination of 2 or more type. Although limitation in particular is not carried out as content of the flame retardant in a resin composition, Preferably it is 0.5 mass % - 10 mass %, More preferably, it is 1 mass % - 9 mass %.

-Organic Fillings-

As an organic filler, you may use arbitrary organic fillers which can be used when forming the insulating layer of a circuit board, For example, a rubber particle, polyamide microparticles|fine-particles, a silicone particle, etc. are mentioned, A rubber particle is preferable.

The rubber particles are not particularly limited as long as they are fine particles of a resin that is chemically crosslinked to a resin exhibiting rubber elasticity and made insoluble and infusible in an organic solvent. For example, acrylonitrile butadiene rubber particle|grains, a butadiene rubber particle, an acrylic rubber particle, etc. are mentioned. Specifically as rubber particles, XER-91 (manufactured by Nippon Kosei Rubber Co., Ltd.), Staphyloid AC3355, AC3816, AC3816N, AC3832, AC4030, AC3364, IM101 (above, manufactured by Aika Kogyo Co., Ltd.) Paraloid EXL2655 , EXL2602 (above, Kureha Chemical Co., Ltd. make) etc. are mentioned.

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. The average particle diameter of the organic filler can be measured using a dynamic light scattering method. For example, the organic filler is uniformly dispersed in an appropriate organic solvent by ultrasonic waves or the like, and the particle size distribution of the organic filler is determined by mass using a thick particle size analyzer ("FPAR-1000" manufactured by Otsuka Denshi Co., Ltd.). It can be measured by creating with and making this median diameter into an average particle diameter. Content of the organic filler in a resin composition becomes like this. Preferably it is 1 mass % - 10 mass %, More preferably, they are 2 mass % - 5 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 organocobalt compounds, and resin additives such as thickeners, defoamers, leveling agents, adhesion-imparting agents, colorants and curable resins. have.

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, still more preferably 50 µm or less, or 40 µm from the viewpoint of reducing the thickness of the circuit board. is below. From the viewpoint of facilitating formation of particularly small-diameter vias, 30 µm or less is preferable, 20 µm or less is more preferable, and 15 µm or less is still more preferable. Although the lower limit of the thickness of a resin composition layer is not specifically limited, Usually, it is 3 micrometers or more.

In the resin sheet with a support body, the multilayer structure which consists of two or more layers may be sufficient as a resin composition layer. When using the resin composition layer of a multilayer structure, it is preferable that the whole thickness exists in the said range.

The resin sheet with a support body can be manufactured by forming a resin composition layer on a plastic film support body.

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

As a solvent used for preparation of a resin varnish, For example, ketone solvents, such as acetone, methyl ethyl ketone, and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, etc. acetic acid ester solvents, carbitol solvents such as cellosolve and butylcarbitol, aromatic hydrocarbon solvents such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. can A solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

You may perform drying of a coating film by well-known drying methods, such as heating and hot air spraying. When the solvent in the resin composition layer remains, it will cause swelling after curing, so that the residual solvent in the resin composition is usually 10% by mass or less, preferably 5% by mass or less. Although it changes also with the boiling point of the organic solvent in a resin varnish, for example, when using the resin varnish containing 30 mass % - 60 mass % of a solvent, by drying at 50 degreeC - 150 degreeC for 3 to 10 minutes, the resin composition layer can form.

In the resin sheet with a support, a protective film conforming to the plastic film support may be further laminated on the surface of the resin composition layer that is not bonded to the plastic film support (that is, the surface opposite to the plastic film support). The thickness of a protective film is not specifically limited, For example, 1 micrometer - 40 micrometers may be sufficient. By laminating|stacking a protective film, adhesion of dust, etc. to the surface of a resin composition layer, and a flaw can be prevented. When the resin sheet with a support body can be wound up in roll shape and preserve|saved, and when manufacturing a circuit board, it becomes usable by peeling off a protective film.

[Method for manufacturing circuit board]

The manufacturing method of the circuit board of this invention includes the following processes (A)-(F) in this order.

(A) a step of laminating a resin sheet with a support comprising a plastic film support and a resin composition layer to be bonded to the plastic film support on an inner-layer substrate such that the resin composition layer is bonded to the inner-layer substrate;

(B) a step of thermosetting the resin composition layer to form an insulating layer, wherein the adhesive strength between the insulating layer and the plastic film support is 2 gf/cm to 18 gf/cm;

(C) a step of forming a via hole with a top diameter of 40 μm or less in the insulating layer by irradiating a laser from above the plastic film support;

(D) the process of performing a desmear process,

(E) a step of peeling the plastic film support, and

(F) A step of forming a conductor layer on the surface of the insulating layer.

In the present invention, "included in this order" with respect to the steps (A) to (F) includes each step of the steps (A) to (F) and each step of the steps (A) to (F). As long as this is performed in this order, it does not interfere with the inclusion of another process. Hereinafter, the same applies to "included in this order" about the process or treatment.

The inventors of the present invention, when manufacturing a circuit board using a resin sheet with a support, by performing desmear treatment in a state where the support is attached to the insulating layer, an insulating layer with high adhesion strength with the conductor layer can be formed with low illuminance. found that it can. However, as described above, when desmearing is performed in a state where the plastic film support is attached to the insulating layer, a region with greater illuminance than other regions (“illuminance band region”) may occur around the via hole opening. The present inventors have found Although this illuminance band region is only formed around the via hole opening, when a via hole with a small diameter (especially a top diameter of 40 µm or less on the surface of the insulating layer) is employed, the corresponding fine circuit wiring is routed through the via hole. Since it is formed in the periphery, the influence of the illuminance band region becomes so large that it cannot be ignored. In order to achieve further densification of the circuit wiring, a technique for reducing the dimension of the illuminance band area generated around the via hole opening is required.

The present inventors, in the process of examining a technique for reducing the dimension of the illuminance band generated around the via hole opening, the adhesive strength between the insulating layer formed through thermosetting and the plastic film support (that is, the insulating layer obtained in the step (B)) and adhesion strength of the plastic film support) were found to have an influence on the dimension of the illuminance band region. And it was discovered that the dimension of an illuminance band area|region can be reduced by making the said adhesive strength more than a predetermined value.

1 and 2, for two embodiments in which the adhesive strength between the insulating layer and the plastic film support is different, the insulating layer surface around the via hole opening after desmearing in the state where the plastic film support is attached to the insulating layer A scanning electron microscope (SEM) picture is shown. In addition, FIGS. 1 and 2 are shown for reference, and it is observed with respect to the via hole of a comparatively large diameter (top diameter 50 micrometers).

1 shows an SEM photograph for an embodiment (comparative embodiment) in which the adhesion strength between an insulating layer and a plastic film support is lower than the desired range in the present invention (ie, 2 to 18 gf/cm). In Fig. 1, (a1) is an SEM photograph of the surface of the insulating layer around the via hole opening after desmearing, and (b1) is an enlarged SEM photograph showing the inside of the dotted line in (a1). In the embodiment of Fig. 1, it is clearly confirmed that a region (illuminance band region) having a greater illuminance than other regions is formed around the via hole opening. As can be seen from Fig. 1, the illuminance band region is formed concentrically with the via hole so as to surround the via hole opening. In the present invention, the dimension of the illuminance band region _{is evaluated by the “length of the illuminance band region” (L r} ), but this is determined by the radius r1 of the via hole opening (inner circle) and the illuminance band region outer periphery (outer circle). It is the difference (r2-r1) with the radius r2 of (outside). In the embodiment of FIG. 1 , it is confirmed that _{the length L r of the illuminance band region exceeds 10 μm.}

2 shows an SEM photograph for an embodiment in which the adhesion strength between the insulating layer and the plastic film support is within the desired range (ie, 2 to 18 gf/cm) in the present invention. In Fig. 2, (a2) is an SEM photograph of the surface of the insulating layer around the via hole opening after desmearing, and (b2) is an enlarged SEM photograph showing the inside of the dotted line in (a2). In the embodiment of FIG. 2 , the length L _r of the illuminance band region formed around the via hole is about 2 μm, and it is confirmed that the dimension of the illuminance band region is remarkably reduced.

Hereinafter, each process is demonstrated.

<Process (A)>

In the step (A), a resin sheet with a support comprising a plastic film support and a resin composition layer to be bonded to the plastic film support is laminated on the inner-layer substrate so that the resin composition layer is bonded to the inner-layer substrate.

The structure of the resin sheet with a support body used at a process (A) is as above-mentioned. In addition, "inner layer 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, a thermosetting polyphenylene ether substrate, or one or both sides of the substrate. It refers to a substrate on which a patterned conductor layer (circuit) is formed. In addition, when manufacturing a circuit board, the inner-layer circuit board of the intermediate|middle manufacture on which an insulating layer and/or a conductor layer should further be formed is also included in the "inner-layer board|substrate" referred to in this invention.

Lamination of the resin sheet with a support body and an inner layer substrate can be performed by thermocompression-bonding the resin sheet with a support body to an inner layer board|substrate from the plastic film support body side, for example. As a member (hereinafter also referred to as a "thermal compression member") for heat-bonding the resin sheet with a support to the inner layer substrate, a heated metal plate (SUS head plate, etc.) or a metal roll (SUS roll), etc. are mentioned, for example. Moreover, it is preferable not to press the thermocompression-compression-bonding member directly to the resin sheet with a support body, but to press through elastic materials, such as a heat-resistant rubber, so that the resin composition layer may fully follow the surface unevenness|corrugation of an inner-layer board|substrate.

The thermocompression pressure is preferably in the range of 80°C to 160°C, more preferably 90°C to 140°C, still more preferably 100°C to 120°C, and the thermocompression pressure is preferably 0.098MPa to 1.77MPa, more It is preferably in the range of 0.29 MPa to 1.47 MPa, and the heat compression time is preferably in the range of 20 seconds to 400 seconds, and more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of a pressure of 26.7 hPa or less.

Lamination can be performed with a commercially available vacuum laminator. As a commercially available vacuum laminator, the vacuum pressurization type laminator by Meiki Sesakusho Co., Ltd. product, the vacuum applicator by Nichigo Morton Co., Ltd. product, etc. are mentioned, for example.

In the process (A), the resin sheet with a support body may be laminated|stacked on the single side|surface of an inner-layer board|substrate, and may be laminated|stacked on both surfaces.

After lamination, a smoothing treatment of the laminated resin sheet with a support may be performed under normal pressure (under atmospheric pressure), for example, by pressing the thermocompression-bonding member from the plastic film support side. The press conditions of the smoothing process can be made into the same conditions as the thermocompression-bonding conditions of the said lamination|stacking. A smoothing process can be implemented with a commercially available laminator. In addition, you may perform lamination|stacking and a smoothing process continuously using said commercially available vacuum laminator.

<Process (B)>

In a process (B), the resin composition layer is thermosetted and an insulating layer is formed. The step (B) is characterized in that the obtained insulating layer and the plastic film support have an adhesive strength of 2 gf/cm to 18 gf/cm.

From the viewpoint of reducing the dimension of the illuminance band region generated around the via hole opening, 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, 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 adhesive strength is too high, when the plastic film support is peeled off in the step (E) to be described later, fragments of the plastic film support are generated from 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 can be easily peeled without the plastic film support remaining, 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 or less. The adhesion strength between the insulating layer and the plastic film support obtained in the step (B) can be measured according to the method described in the <Measurement of the adhesion strength between the insulating layer and the plastic film support> below.

In a process (B), the thermosetting conditions of a resin composition layer are not specifically limited as long as the said desired adhesive strength is obtained. For example, the thermosetting conditions of the resin composition layer, depending on the type of the plastic film support, the composition of the resin composition layer, etc., the curing temperature is in the range of 120 ° C to 240 ° C (preferably in the range of 150 ° C to 210 ° C, more preferably Preferably in the range of 160 ° C. to 200 ° C.), the curing time is in the range of 5 minutes to 90 minutes (preferably 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes), so that the desired adhesion strength is obtained. You may decide appropriately. In addition, the pressure at the time of thermosetting is not specifically limited, Any of under normal pressure, under pressure, and under reduced pressure may be sufficient as long as the said desired adhesive strength is obtained.

Before thermosetting the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition layer, at a temperature of 50 ° C. or more and less than 120 ° C. (preferably 60 ° C. or more and 110 ° C. or less), the resin composition layer is heated for 5 minutes or more (preferably from 5 minutes to 150 ° C). min) may be preheated.

By carrying out the step (B) so that the adhesion strength between the obtained insulating layer and the plastic film support falls within the predetermined range, it becomes possible to reduce the dimension of the illuminance band region generated around the via hole opening.

<Process (C)>

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

The top diameter (diameter of the opening at the surface of the insulating layer) of the via hole formed in the step (C) is preferably less than 40 µm, more preferably 35 µm or less, and 30 µm or less from the viewpoint of further increasing the density of circuit wiring. more preferably. According to the method of the present invention employing the step (B), it is possible to reduce the dimension of the illuminance band region generated around the via hole opening, and even when a via hole with a smaller diameter is employed, the corresponding fine circuit wiring can be connected to the via hole. can be formed around In the method of the present invention, while maintaining good fine wiring formability, for example, 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. A via hole having a top diameter of mu m or less may be employed. Although the lower limit of the top diameter of a via hole is not specifically limited, Usually, it can be 3 micrometers or more, 8 micrometers or more, etc.

The number of via holes formed in the step (C) is not particularly limited, and may be appropriately determined according to the design of the circuit board. The top diameters of the plurality of via holes to be formed may be the same or different. In addition, it is not necessary that all of the via holes formed in the step (C) have a tower diameter of 40 µm or less. Depending on the design of the circuit board, via holes having a top diameter exceeding 40 mu m may be formed together.

In the step (C), examples of the laser light source include carbon dioxide laser, YAG laser, UV-YAG laser, YVO ₄ laser, YLF laser, and excimer laser. A suitable laser light source may be used depending on the light absorption characteristics of the plastic film support and the insulating layer.

The laser irradiation conditions are not particularly limited as long as a via hole having a small diameter can be formed, and may be appropriately determined according to the type of the laser light source, the thickness and type of the plastic film support and the insulating layer, and the like. Hereinafter, irradiation conditions in the case of using a carbon dioxide laser as a laser light source are illustrated. When a carbon dioxide laser is used as the laser light source, generally laser light having a wavelength of 9.3 µm to 10.6 µm is used. The number of shots also varies depending on the depth of the via hole to be formed and the diameter of the tower, but is usually selected in the range of 1 to 10 shots. From the viewpoint of increasing the processing speed and improving the productivity of the circuit board, the number of shots is preferably small, preferably in the range of 1 to 5 shots, and more preferably in the range of 1 to 3 shots. In addition, when the number of shots is 2 or more, you may irradiate a laser beam in either mode of a burst mode and a cycle mode. The energy of the laser light 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 0.2 mJ or more, more preferably 0.3 mJ or more, still more 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 still more preferably 10 mJ or less.

You may implement a process (C) using a commercially available laser apparatus. As a commercially available laser apparatus, Hitachi Bia Mechanicus Co., Ltd. "LC-2E21B/1C" (carbon dioxide laser apparatus), Mitsubishi Denki Co., Ltd. product "605GTWIII(-P)" (carbon dioxide laser apparatus) is, for example, ), "MODEL 5330xi" by ESI, "MODEL 5335" (UV-YAG laser device), etc. are mentioned.

<Process (D)>

A desmear process is performed at a process (D).

Generally, resin residue (smear) adheres to the inside of the via hole formed in the step (C) (particularly, the bottom of the via hole). Since such a smear becomes a cause of the electrical connection defect between layers, the process (desmear process) which removes a smear in a process (D) is performed.

In the manufacturing method of the circuit board of this invention, the desmear process is performed in the state which the plastic film support body adhered to the insulating layer. Unlike the conventionally known technique of performing desmear treatment after peeling off the support, since the surface of the insulating layer is protected with a plastic film support, the surface of the insulating layer is not roughened, and the smear inside the via hole can be removed have. Moreover, since there is no restriction|limiting that the surface of an insulating layer receives damage, a wide range of desmear processing methods and desmear processing conditions are employable. Accordingly, even when using a resin composition (for example, a resin composition containing an active ester-based curing agent) that results in a resin residue (smear) that is difficult to remove by desmearing as a resin composition for forming the insulating layer , it becomes possible to effectively remove the smear without increasing the roughness of the surface of the insulating layer.

As described above, when desmearing is performed while the plastic film support is attached to the insulating layer, the illuminance band region generated around the via hole opening becomes a problem, but in the present invention employing the above specific step (B) According to the method, it is possible to reduce the dimension of the illuminance band region generated around the via hole opening.

A process (D) WHEREIN: A desmear process is not specifically limited, It can implement by well-known various methods. You may perform a desmear process by a dry desmear process, a wet desmear process, or these combination, for example.

As a dry desmear process, the desmear process etc. using plasma are mentioned, for example. Regarding desmear treatment using plasma, it is known that the adhesion strength between the insulating layer and the conductor layer tends to decrease due to surface modification of the insulating layer by plasma, etc. In the method of the present invention in which the treatment is carried out, desmear treatment can be advantageously performed without modification of the surface of the insulating layer.

The desmear processing using plasma can be implemented using a commercially available plasma desmear processing apparatus. Among commercially available plasma desmear processing apparatuses, as an example suitable for the manufacturing use of a printed wiring board, the microwave plasma apparatus by Nisshin Corporation, the atmospheric pressure plasma etching apparatus by the Sekisui Chemical Co., Ltd. product, etc. are mentioned.

As a dry desmear process, you may use the dry sandblasting process which can grind|polish a process object by spraying an abrasive material from a nozzle further. Dry sand blasting can be performed using a commercially available dry sand blasting apparatus. When a water-soluble abrasive is used as the abrasive, by washing with water after the dry sandblasting treatment, the abrasive does not remain inside the via hole and smear can be effectively removed.

As a wet desmear process, the desmear process etc. using the oxidizing agent solution are mentioned, for example. When desmearing using an oxidizing agent solution, it is preferable to perform the swelling process by a swelling liquid, the oxidation process by an oxidizing agent solution, and the neutralization process by a neutralizing liquid in this order. As a swelling liquid, "Swelling Deep Securiganth P" and "Swelling Deep Securiganth SBU" manufactured by Atotech Japan Co., Ltd. are mentioned, for example. It is preferable to perform a swelling process by immersing the board|substrate with a via hole in the swelling liquid heated at 60 degreeC - 80 degreeC for 5 minutes - 10 minutes. As an oxidizing agent solution, alkaline permanganic acid aqueous solution is preferable, for example, the solution which melt|dissolved potassium permanganate and sodium permanganate in the aqueous solution of sodium hydroxide is mentioned. It is preferable to carry out the oxidation treatment by an oxidizing agent solution by immersing the board|substrate after a swelling process in the oxidizing agent solution heated at 60 degreeC - 80 degreeC for 10 minutes - 30 minutes. As a commercial item of alkaline permanganic acid aqueous solution, "Concentrate Compact CP" by Atotech Japan Co., Ltd. product, "Dosing solution Securiganth P", etc. are mentioned, for example. The neutralization treatment with the neutralizing solution is preferably performed by immersing the substrate after the oxidation treatment in a neutralizing solution at 30°C to 50°C for 3 minutes to 10 minutes. As a neutralizing liquid, an acidic aqueous solution is preferable, and as a commercial item, "Reduction Solution Security P" manufactured by Atotech Japan Co., Ltd. is mentioned, for example.

As a wet desmear process, you may use the sandblasting process which can grind|polish a process object by spraying an abrasive and a dispersion medium from a nozzle further. Wet sand blasting can be performed using a commercially available wet sand blasting apparatus.

When carrying out combining a dry desmear process and a wet desmear process, a dry desmear process may be performed first, and a wet desmear process may be performed first.

The present inventors have found that, in the wet desmear treatment, the size of the illuminance band region generated around the via hole opening tends to increase, but according to the method of the present invention employing the above specific step (B), the wet desmear treatment It is possible to advantageously reduce the dimension of the illuminance band region even in the case of carrying out

It is preferable that the desmear process of a process (D) is a wet desmear process from a viewpoint which can enjoy the effect of this invention more.

<Process (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 may be peeled manually or may be peeled mechanically by an automatic peeling device.

During the desmear treatment in step (D), since the surface of the insulating layer was protected by the plastic film support, the surface of the insulating layer exposed in this step has a low roughness (for the value of the roughness of the insulating layer surface, will be described later). In addition, according to the method of the present invention, it is possible to advantageously reduce the dimension of the illuminance band region generated around the via hole opening ( _{the value of the illuminance band length L r} will be described later). Therefore, the surface of the insulating layer exposed in this step is suitable for forming fine circuit wiring thereon.

<Process (F)>

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

The conductor material used for a conductor layer is not specifically limited. In a suitable embodiment, the conductor layer comprises one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. . The conductor layer may be a single metal layer or an alloy layer, and as the alloy layer, for example, an alloy of two or more metals selected from the group described above (eg, nickel-chromium alloy, copper-nickel alloy) and a layer formed of a copper/titanium alloy). Among them, single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel/chromium alloys, copper/nickel alloys, and copper from the viewpoints of versatility of conductor layer formation, cost, ease of patterning, etc. - An alloy layer of a titanium alloy is preferable, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of a nickel-chromium alloy is more preferable, and a single metal layer of copper is still more preferable .

The conductor layer may have a single layer structure or a multilayer structure in which two or more single metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductor layer has a multilayer 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 a nickel-chromium alloy.

The thickness of the conductor layer depends on the desired design of the circuit board, but is usually 35 µm or less, preferably 30 µm or less, and more preferably 25 µm or less. Although the lower limit of the thickness of a conductor layer is not specifically limited, Usually, it is 3 micrometers or more, Preferably it is 5 micrometers or more.

In one embodiment, the step (F),

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 a metal layer

is included in this order (hereinafter, such a step is referred to as "step (F-1)").

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

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

Although the thickness of a metal layer is not specifically limited, Preferably it is 5 nm - 2 micrometers, More preferably, it is 10 nm - 1 micrometer, More preferably, it is 20 nm - 500 nm. In addition, a single layer structure or a multilayer structure may be sufficient as a metal layer. When a metal layer has a multilayer structure, it is preferable that the thickness of the whole metal layer exists in the said range.

In a process (F-1), after formation of a metal layer, wet plating is carried out on the surface of the said metal layer, and a conductor layer is formed.

A conductor layer having a desired pattern can be formed by using a metal layer as a plating seed layer and performing wet plating by a semi-additive method. In detail, on the plating seed layer (metal layer), a mask pattern for exposing a part of the plating seed layer in correspondence to a desired wiring pattern is formed. After forming a conductor layer by electrolytic plating on the exposed plating seed layer, the mask pattern is removed. Thereafter, the unnecessary plating seed layer is removed by etching or the like to form a conductor layer having a desired wiring pattern.

When a via hole with a small diameter is employed, a corresponding fine circuit wiring is formed around the via hole. However, if the size of the illuminance band region formed around the via hole opening is large, the plating seed layer in the illuminance band region is difficult to remove when the unnecessary plating seed layer is removed by etching when forming the wiring pattern. In the case of etching under conditions in which the layer can be sufficiently removed, dissolution of the wiring pattern becomes remarkable, and it becomes difficult to form fine circuit wiring around the via hole. In this respect, according to the method of the present invention employing the specific step (B), the size of the illuminance band region generated around the via hole opening can be remarkably reduced. The wiring can be formed in a desired wiring pattern. Therefore, the manufacturing method of the circuit board of this invention contributes remarkably to refinement|miniaturization and density increase of circuit wiring.

Moreover, at a process (F-1), although sufficient adhesive strength of an insulating layer and a conductor layer can be achieved without roughening the surface of an insulating layer, you may roughen the surface of an insulating layer. In this case, the step (F-1) is

roughening the surface of the insulating layer;

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 a metal layer

are included in this order.

As a roughening process, a dry roughening process and a wet roughening process are mentioned, for example, You may perform a roughening process combining these.

A dry roughening process can be carried out similarly to the dry desmear process mentioned above, and can be implemented. In addition, a wet roughening process can be carried out similarly to the wet desmear process mentioned above, and can be implemented. When carrying out combining a dry roughening process and a wet roughening process, a dry roughening process may be performed first, and a wet roughening process may be performed first. Although the roughening process aims at the roughening of the exposed surface of an insulating layer, it shows a certain effect also regarding the smear removal inside a via hole. Therefore, even when a process (D) is implemented on mild conditions, the residual of a smear can be prevented.

In another embodiment, the step (F),

roughening the surface of the insulating layer, and

Forming a conductor layer by wet plating on the surface of the insulating layer

is included in this order (hereinafter, such a step is referred to as "step (F-2)").

It is as above-mentioned about a roughening process.

At a process (F-2), after roughening the surface of an insulating layer, wet plating is carried out on the surface of an insulating layer, and a conductor layer is formed.

For example, a conductor layer having a desired wiring pattern can be formed by a semi-additive method by combining electroless plating and electrolytic plating. According to the method of the present invention, which can reduce the size of the illuminance band region generated around the via hole opening, it is possible to form a corresponding fine circuit wiring around a small diameter via hole in a desired wiring pattern.

Since the surface roughness of the insulating layer obtained is still lower and it contributes more to refinement|miniaturization and density increase of circuit wiring, as a process (F), a process (F-1) is preferable.

[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 the dimension of the illuminance band area around the via hole opening is small.

In one embodiment, the circuit board of the present invention comprises:

an insulating layer, and a conductor layer formed on the insulating layer;

A via hole having a top diameter of 40 μm or less is formed in the insulating layer,

_{It is characterized in that the length (L r} ) of the illuminance band region around the via hole opening on the surface of the insulating layer is less than 10 μm.

The insulating layer and the conductor layer are as described above. Moreover, the suitable range of the top diameter of the via hole formed in the insulating layer is also as above-mentioned.

_{The length (L r} ) of the illuminance band region around the via hole opening is preferably 8 μm or less, more preferably 6 μm or less, still more preferably from the viewpoint of forming fine circuit wiring around the via hole. 5 µm or less, 4 µm or less, 3 µm or less, or 2 µm or less. The lower limit of the length (L _r ) of the illuminance band region is preferably smaller, and may be 0 µm, but is usually 0.1 µm or more. In addition, the arithmetic mean roughness Ra of the illuminance band region around the via hole opening is usually higher than 200 nm.

In the circuit board of the present invention, the line width of the conductor layer (circuit wiring) formed around the via hole opening so as to conduct with the via hole is preferably 40 µm or less, more preferably 30 µm or less, still more preferably 20 µm or less. am. In the circuit board of the present invention having a small dimension of the illuminance band region around the via hole opening, a conductor layer having a small line width can be formed around the via hole opening. In the circuit board of the present invention, the line width of the conductor layer formed around the via hole opening so as to conduct with the via hole is, for example, 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, 8 μm or less. Hereinafter, it is possible to make it small down to 6 micrometers or less, or 4 micrometers or less. Although the lower limit of the said line|wire width is not specifically limited, Usually, it can be set as 1 micrometer or more.

Further, 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. In addition, the following values of Ra and Rq are values measured for a region located at a sufficient distance (preferably 100 µm or more) from the via hole opening end to such an extent that the influence of the illuminance band 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, particularly preferably preferably 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, or 60 nm or less. Although the lower limit of Ra value is not specifically limited, In order to stabilize the adhesive strength with a conductor layer, it can be set as 0.5 nm or more, 1 nm or more, etc. In addition, the root mean square roughness (Rq) of the surface of the insulating layer is preferably 250 nm or less, more preferably 200 nm or less, still more preferably 150 nm or less, still more preferably 130 nm or less, 110 nm or less, or 90 nm or less. . Although the lower limit of Rq value is not specifically limited, In order to stabilize the adhesive strength with a conductor layer, it can be set as 10 nm or more, 30 nm or more, etc. 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. As a specific example of a non-contact type surface roughness meter, "WYKO NT3300" by BCoins Lumens Co., Ltd. is mentioned.

The circuit board produced by the method of the present invention has sufficient adhesion strength (peel strength) to the surface of the insulating layer, that is, preferably 0.4 kgf/cm or more, even though the roughness of the surface of the insulating layer is low as described above. , more preferably 0.45 kgf/cm or more, still more preferably 0.5 kgf/cm or more, still more preferably 0.54 kgf/cm or more. Although it is so preferable that the said adhesive strength is high, generally 1.5 kgf/cm becomes an upper limit. The measurement of the peeling strength of an insulating layer and a conductor layer can be performed based on JISC6481.

[Semiconductor device]

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

Examples of such semiconductor devices include various semiconductor devices used in electrical products (eg, computers, mobile phones, digital cameras, and televisions) and vehicles (eg, motorcycles, automobiles, trams, ships, and aircraft). can

Example

Hereinafter, the present invention will be specifically described by way of Examples, but the present invention is not limited to these Examples. In addition, in the following, "part" and "%" mean "part by mass" and "mass %", respectively, unless otherwise indicated.

First, various measurement methods and evaluation methods are demonstrated.

[Preparation of samples for measurement and evaluation]

(1) Underlay treatment of inner-layer circuit board

Both sides of a glass cloth base epoxy resin double-sided laminate (copper foil thickness 18 μm, substrate thickness 0.3 mm, size 500 mm × 500 mm, “R5715ES” manufactured by Panasonic Co., Ltd.) on which the inner circuit was formed ) 1 µm etching was performed with "CZ8100" manufactured, and roughening treatment of the copper surface was performed.

(2) Lamination of a resin sheet with a support body

The protective film of the resin sheet with a support body (size 494 mm x 494 mm) produced in the following Production Example was peeled off, and a batch type vacuum pressurization laminator (Nichigo Morton Co., Ltd. 2 stage build-up laminator CVP700) was used, and the resin composition The layers were laminated on both sides of the inner-layer circuit board so that the layers were in contact with the inner-layer circuit board. Lamination|stacking was performed by pressure-reducing for 30 second and making atmospheric|air pressure 13 hPa or less, and then crimping|bonding at 100 degreeC and pressure 0.74 MPa for 30 second. Then, it hot-pressed for 60 second at 100 degreeC and the pressure of 0.5 MPa.

(3) Hardening of the resin composition layer

The laminated resin sheet with a support body was heated at 100 degreeC for 30 minute(s), then 170 degreeC for 30 minute(s), the resin composition layer was thermosetted, and the insulating layer was formed. The obtained board|substrate is called "evaluation board|substrate A".

(4) Formation of via holes

A laser was irradiated from above the plastic film support to form a via hole of a small diameter in the insulating layer. For Example 1 and Comparative Example 1 according to the procedure of (A), for Example 2 and Comparative Example 2 according to the procedure of (B), for Example 3 according to the procedure of (C), In Example 4, a via hole having a small diameter was formed according to the procedure of (D) below.

(A) Using Mitsubishi Denki Co., Ltd. produced CO ₂ laser processing machine "605GTWIII (-P)", a laser beam from above the plastic film support, thereby forming a via hole in the tower diameter 30㎛ in the insulating layer. The laser irradiation conditions were a mask diameter of 1 mm, a pulse width of 16 µs, an energy of 0.2 mJ/shot, the number of shots 2, and a burst mode (10 kHz).

(B) Using a UV-YAG laser processing machine "MODEL 5330xi" manufactured by ESI Corporation, laser was irradiated from the top of the plastic film support, and a via hole having a top diameter of 20 µm was formed in the insulating layer. The laser irradiation conditions were: Z offset 0.0mm, power 0.40W, Bite Size: 1.15㎛, Velocity: 69mm/sec, Rep Rate: 60kHz, Repetition: 3, It was in circle/punch mode.

(C) Using a UV-YAG laser-processing machine "MODEL 5330xi" manufactured by ESI Corporation, laser was irradiated from above the plastic film support, and a via hole having a top diameter of 15 µm was formed in the insulating layer. The laser irradiation conditions were: Z offset 0.0 mm, power 0.40 W, bite size: 2.0 µm, velocity: 120 mm/sec, repetition rate: 60 kHz, repetition: 15, circle/punch mode.

_{(D) Using a CO 2} laser processing machine "605GTVIII(-P)" manufactured by Mitsubishi Denki Co., Ltd., a laser was irradiated from above the plastic film support, and a via hole having a top diameter of 12 µm was formed in the insulating layer. The laser irradiation conditions were a mask diameter of 0.7 mm, a pulse width of 12 µs, an energy of 0.15 mJ/shot, the number of shots 3, and a cycle mode.

(5) desmear treatment

After the via hole was formed, a desmear treatment was performed in a state in which the plastic film support was attached to the insulating layer. Moreover, as a desmear process, the following wet desmear process (Examples 1-3, Comparative Examples 1-2) and a dry desmear process (Example 4) were implemented.

Wet desmear treatment:

The substrate with via holes was placed in a swelling solution (Atotech Japan Co., Ltd. “Swelling Deep Security P”, an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60° C. for 5 minutes, followed by an oxidizing agent solution ( "Concentrate Compact CP" manufactured by Atotech Japan Co., Ltd., in an aqueous solution with a potassium permanganate concentration of about 6% and sodium hydroxide concentration of about 4%) at 80° C. for 20 minutes, and finally a neutralizing solution (manufactured by Atotech Japan Co., Ltd.) "Reduction solution Securiganth P", sulfuric acid aqueous solution) was immersed at 40°C for 5 minutes, and then dried at 80°C for 15 minutes.

Dry desmear treatment:

_{The substrate on which the via hole was formed was processed for 5 minutes under conditions of O 2} /CF ₄ (mixed gas ratio) = 25/75 and a vacuum degree of 100 Pa using a vacuum plasma etching apparatus (100-E PLASMA SYSTEM manufactured by Tepla Corporation).

(6) Peeling of the plastic film support

After the desmear treatment, the plastic film support was peeled off according to the following procedure to expose the surface of the insulating layer. First, with respect to one of the four substrates after desmearing, the vibrating pen was pressed from the top of the plastic film support to form a peeling part. The peeling part was held by hand, and the plastic film support body was peeled at once in the diagonal direction of a board|substrate. The obtained board|substrate is called "evaluation board|substrate B".

(7) Formation of conductor layer

A conductor layer was formed on the exposed surface of the insulating layer. The conductor layer was formed by a dry method according to the following procedure. The obtained board|substrate is called "evaluation board|substrate C". In addition, the following dry method corresponds to the above-mentioned process (F-1).

Dry method:

After the evaluation substrate B was heated at 150° C. for 30 minutes, a titanium layer (thickness 30 nm), followed by a copper layer (thickness 300 nm) on the insulating layer using a sputtering device (“E-400S” manufactured by Canon Anelbar Co., Ltd.) was formed, and a plating seed layer was formed. Next, an etching resist was formed according to the semi-additive method, and after formation of the mask pattern by exposure and development, copper sulfate electrolytic plating was performed, and the conductor layer (25 micrometers in thickness) was formed. After the mask pattern was removed, the unnecessary plating seed layer was removed by etching (copper etching solution: SAC manufactured by JCU Corporation, titanium etching solution: Ryoko Chemical Co., Ltd. WLC-T) to form a conductor pattern. The obtained substrate was heated at 190°C for 60 minutes to perform annealing treatment.

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

The adhesion strength between the insulating layer and the plastic film support was measured with respect to the evaluation substrate A according to the following procedure. The evaluation substrate A was cut to the dimensions of 30 mm in width and 150 mm in length so that it might become long in the longitudinal direction (MD direction) of a plastic film support body. Next, from the side of the plastic film support body, a cut was made with a cutter in dimensions of 15 mm in width and 100 mm in length. Peel one end of the plastic film support from the insulating layer, hold it with a holding tool, and measure the load when the plastic film support is peeled off by 30 mm in the vertical direction at a speed of 50 mm/min at room temperature (23°C) to determine the adhesion strength. did. A tensile tester ("AC-50C-SL" manufactured by TSE Corporation) was used for the measurement.

<2. Evaluation of Peelability of Plastic Film Supports>

About the evaluation board|substrate B, the peelability of the plastic film support body was evaluated. Both surfaces (ie, all 10 surfaces) of the five evaluation substrates B were observed to determine the presence or absence of residual plastic film support. And peelability was evaluated according to the following criteria. In addition, when evaluation was "x", subsequent evaluation of 3.-6 was not implemented.

Evaluation standard:

(circle): Residual of a plastic film support body is not confirmed with respect to all surfaces.

×: Residual of the plastic film support is confirmed with respect to one or more surfaces.

<3. Evaluation of the dimensions of the illuminance zone>

For the evaluation substrate B, the periphery of the via hole opening was observed with a scanning electron microscope (SEM), and the length (L _r ) of the illuminance band region around the via hole opening was measured from the obtained image. _{The length L r} of the illuminance band region is the difference (r2-r1) between the radius r1 of the via hole opening (inner circle) and the radius r2 of the illuminance band region outer periphery (outer circle). _{L r} was obtained for 10 via holes, and the dimensions of the illuminance band were evaluated according to the following criteria.

Evaluation standard:

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

_{×: L r} is 10 μm or more for one or more via holes

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

With respect to the evaluation substrate B, using a non-contact type surface roughness meter ("WYKO NT3300" manufactured by BCoins Lumens Co., Ltd.), in VSI contact mode, the measurement range is 121 µm × 92 µm with a 50x lens Ra by a numerical value obtained The value, Rq value was calculated|required. Measurements were made by obtaining the average value of 10 randomly selected points for an area separated by 100 µm or more from the end of the via hole opening.

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

The measurement of the peeling strength of an insulating layer and a conductor layer was performed based on JISC6481 about the evaluation board|substrate C. Specifically, in the conductor layer of the evaluation board D, an incision having dimensions of 10 mm in width and 100 mm in length was made, one end was peeled off and held with a holding tool, and 35 mm was peeled off in the vertical direction at a rate of 50 mm/min at room temperature. The load (kgf/cm) at the time was measured, and the adhesive strength was calculated|required. A tensile tester ("AC-50C-SL" manufactured by TSE Corporation) was used for the measurement.

<6. Evaluation of Smear Removability>

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

Evaluation standard:

○: The maximum smear length is less than 3㎛

×: The maximum smear length is 3 µm or more

<Preparation Example 1> Preparation of resin varnish 1

5 parts of bisphenol-type epoxy resin (epoxy equivalent of about 165, "ZX1059" manufactured by Shin-Nittetsu Chemical Co., Ltd., 1:1 mixture of bisphenol A and bisphenol F) 5 parts, bixylenol-type epoxy resin (epoxy equivalent of about 185) , Mitsubishi Chemical Co., Ltd. "YX4000HK") 10 parts, biphenyl type epoxy resin (epoxy equivalent about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.) 10 parts, and phenoxy resin (Mitsubishi Chemical Co., Ltd.) ) Production "YL7553BH30", 10 parts of methyl ethyl ketone (MEK) solution of 30 mass % of solid content) was heat-dissolved, stirring 20 parts of solvent naphtha. After cooling to room temperature, 12 parts of a naphthol-based curing agent (hydroxyl equivalent 215, "SN-485" manufactured by Shin-Nittetsu Chemical Co., Ltd., MEK solution having a solid content of 60%), triazine skeleton-containing phenol novolac 8 parts of curing agent (hydroxyl equivalent 125, "LA-7054" manufactured by DIC Corporation, MEK solution having a solid content of 60%), 4 parts of a curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution having a solid content of 2% by mass) , Flame retardant (“HCA-HQ” manufactured by Sanko Co., Ltd., 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle diameter 1 μm) 2 parts, rubber particles (Aika Kogyo Co., Ltd. "Staphyloid AC3816N") 3 parts, aminosilane-based coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573") surface-treated spherical silica (Co., Ltd.) ) Adomatex manufactured "SOC1", average particle diameter 0.24 μm, particles of 3 μm or more are removed by classification, carbon amount per unit surface area 0.36 mg/m2) 90 parts are mixed, and uniformly dispersed with a high-speed rotary mixer to resin Varnish 1 was prepared.

<Production Example 1> Preparation of the resin sheet 1 with a support body

As a plastic film support, a PET film (“Lumiror T6AM” manufactured by Toray Co., Ltd.), 25 μm thick, treated with a non-silicone mold release agent (“NSP-4” manufactured by Fuji Morikogyo Co., Ltd.) ) was prepared. The resin varnish 1 was apply|coated to the release surface of the said plastic film support body with a die coater, and it dried at 80 degreeC - 110 degreeC (average 100 degreeC) for 4 minutes, and the resin composition layer was formed. The thickness of the resin composition layer was 20 µm. Next, on the surface of the resin composition layer that is not bonded to the plastic film support, as a protective film, the rough surface side of a polypropylene film ("Alpan MA-411" manufactured by Ojito Kushushi Co., Ltd., 15 µm in thickness) were joined to obtain a resin sheet 1 with a support.

<Production Example 2> Preparation of the resin sheet 2 with a support body

As a plastic film support, a PEN film (“Theonex Q83” manufactured by Tejin DuPont Film Co., Ltd., “Theonex Q83” manufactured by Tejin DuPont Film Co., Ltd.), thickness 25, treated with a heavy release type silicone-containing mold release agent (“SK-1” manufactured by Lintec Co., Ltd.) μm) was prepared. The resin varnish 1 was apply|coated to the release surface of the said plastic film support body with a die coater, and it dried at 80 degreeC - 110 degreeC (average 100 degreeC) for 3 minutes, and the resin composition layer was formed. The thickness of the resin composition layer was 15 µm. Next, the rough side of the polypropylene film ("Alpan MA-411" manufactured by Ojito Kushushi Co., Ltd., 15 µm thick) as a protective film is bonded to the surface that is not bonded to the plastic film support of the resin composition layer, A resin sheet 2 with a support was obtained.

<Production Example 3> Preparation of the resin sheet 3 with a support body

As a plastic film support, a PEN film (“Theonex Q83” manufactured by Tejin DuPont Film Co., Ltd., “Theonex Q83” manufactured by Tejin DuPont Film Co., Ltd.), thickness 25, treated with a non-silicone type release agent (“AL-5” manufactured by Lintec Co., Ltd.) μm) was used, and a resin sheet 3 with a support was obtained in the same manner as in Production Example 2.

<Production Example 4> Preparation of the resin sheet 4 with a support body

As a plastic film support, a PET film (“Lumiror T6AM” manufactured by Toray Co., Ltd., 50 μm thick) treated with a non-silicone mold release agent (“AL-5” manufactured by Lintec Co., Ltd.) was prepared. The resin varnish 1 was apply|coated to the release surface of the said plastic film support body with a die coater, and it dried at 80 degreeC - 110 degreeC (average of 100 degreeC) for 2 minutes, and the resin composition layer was formed. The thickness of the resin composition layer was 10 µm. Next, the rough side of the polypropylene film ("Alpan MA-411" manufactured by Ojito Kushushi Co., Ltd., 15 µm thick) as a protective film is bonded to the surface that is not bonded to the plastic film support of the resin composition layer, A resin sheet 4 with a support was obtained.

<Production Example 5> Preparation of the resin sheet 5 with a support body

As a plastic film support, a PET film (“Lumiror T6AM” manufactured by Toray Co., Ltd., 25 μm thick) treated with a non-silicone-based mold release agent (“NSP-5” manufactured by Fuji Morikogyo Co., Ltd.) as a plastic film support. ) was used, and a resin sheet 5 with a support was obtained in the same manner as in Production Example 1.

<Production Example 6> Preparation of the resin sheet 6 with a support body

As a plastic film support, a PEN film (“Theonex Q83” manufactured by Tejin DuPont Film Co., Ltd., 25㎛ thick) treated with a silicone-containing mold 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 .

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

As shown in Table 2, circuit boards were manufactured using the resin sheets 1 to 6 with a support according to the procedure of the above [Preparation of samples for measurement and evaluation]. Each evaluation result is described in Table 2.

In Comparative Example 1, in which the adhesive strength between the insulating layer after thermosetting and the plastic film support was high at 19 gf/cm, when the plastic film support was peeled off, fragments of the plastic film support were generated from the via hole as a starting point, and the surface of the insulation layer was plastic It was confirmed that a part of the film support remained (remaining of the plastic film support was confirmed for 4 sides). In Comparative Example 2, in which the adhesion strength was as low as 1 gf/cm, the size of the illuminance band formed around the via hole opening was large.

On the other hand, in Examples 1 to 4 in which the adhesive strength between the insulating layer and the plastic film support after thermosetting was in the range of 2 gf/cm to 18 gf/cm, it was confirmed that the dimension of the illuminance band region generated around the via hole opening was significantly reduced. . In Examples 1-4, while being able to form the insulating layer with high adhesive strength with a conductor layer while being low illumination intensity, it was also confirmed that the outstanding smear removability was also exhibited.

Claims (13)

(A) a step of laminating a resin sheet with a support comprising a plastic film support and a resin composition layer to be bonded to the plastic film support on an inner-layer substrate such that the resin composition layer is bonded to the inner-layer substrate;
(B) a step of thermosetting the resin composition layer to form an insulating layer, wherein the adhesive strength between the insulating layer and the plastic film support is 2 gf/cm to 18 gf/cm;
(C) a step of forming a via hole with a top diameter of 40 μm or less in the insulating layer by irradiating a laser from above the plastic film support;
(D) the process of performing a desmear process,
(E) a step of peeling the plastic film support, and
(F) Step of forming a conductor layer on the surface of the insulating layer
A method of manufacturing a circuit board comprising in this order. The manufacturing method of the circuit board of Claim 1 whose desmear process of a process (D) is a wet desmear process. The method according to claim 1, wherein step (F) comprises:
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 a metal layer
A method of manufacturing a circuit board comprising in this order. The method for manufacturing a circuit board according to claim 1, wherein the plastic film support is a plastic film support with a release layer. The manufacturing method of the circuit board of Claim 1 in which the resin composition layer contains an epoxy resin, a hardening|curing agent, and an inorganic filler. The manufacturing method of the circuit board of Claim 5 whose average particle diameter of an inorganic filler is 0.01 micrometer - 3 micrometers. The manufacturing method of the circuit board of Claim 5 whose average particle diameter of an inorganic filler is 0.01 micrometer - 0.4 micrometer. The manufacturing method of the circuit board of Claim 5 whose content of the inorganic filler in a resin composition layer is 40 mass % - 95 mass %, when the non-volatile component in a resin composition layer makes 100 mass %. The method for manufacturing a circuit board according to claim 5, wherein the inorganic filler is surface-treated with a surface treatment agent. A circuit board comprising an insulating layer and a conductor layer formed on the insulating layer, the circuit board comprising:
A via hole having a top diameter of 40 μm or less is formed in the insulating layer,
The length of the roughness band region around the via hole opening on the surface of the insulating layer is less than 10 μm;
The illuminance band region is a region having an arithmetic mean illuminance (Ra) higher than 200 nm. The circuit board according to claim 10, wherein the surface of the insulating layer has an arithmetic mean roughness (Ra) of 200 nm or less. A semiconductor device comprising the circuit board according to claim 10 or 11 . delete

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