JP2015211085A - Method of manufacturing circuit board - Google Patents

Abstract

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

Description

  The present invention relates to a circuit board manufacturing method.

  Circuit boards widely used in various electronic devices are required to have finer and higher density circuit wiring in order to reduce the size and increase the functionality of electronic devices. As a circuit board manufacturing technique, a manufacturing method based on a build-up method in which insulating layers and conductor layers are alternately stacked on an inner layer substrate is known. In the manufacturing method using the build-up method, the insulating layer is formed by laminating the resin composition layer on the 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, a hole is formed in the formed insulating layer to form a via hole, and a desmear treatment is performed to simultaneously remove the resin residue (smear) inside the via hole and roughen the surface of the insulating layer (for example, Patent Documents) 1).

JP 2008-37957 A

  In the manufacturing method by the build-up method, a conductor layer is formed on the surface of the insulating layer after the desmear process. At this time, if the unevenness on the surface of the insulating layer after the desmear treatment is large, circuit wiring becomes difficult to be miniaturized. Therefore, the roughness of the surface of the insulating layer realizes sufficient adhesion strength (peel strength) with the conductor layer. It is desirable to keep it as low as possible. In this regard, the present inventors, when manufacturing a circuit board using a resin sheet with a support, conducts a desmear process in a state where the support is attached to the insulating layer, so that the conductor is low in roughness. It has been found that an insulating layer having high adhesion strength with the layer can be formed. According to such a technique, since the restriction that the surface of the insulating layer is damaged during the desmear treatment is greatly relaxed, a wide range of desmear treatment methods and desmear treatment conditions can be adopted, and the insulation layer is configured. The smear can be effectively removed regardless of the composition of the resin composition.

  On the other hand, the via hole has a tendency to be reduced in diameter while further increasing the density of the circuit wiring. When manufacturing a circuit board having a small-diameter via hole using the above-described technique for performing desmearing with a support attached to an insulating layer, it is easy to form a small-diameter via hole by laser irradiation during drilling. As the support, a plastic film support is suitable. However, when the desmear process is performed with the plastic film support attached to the insulating layer, the inventors of the present invention have a region with a larger roughness than the other regions (also referred to as “roughness region”) around the opening of the via hole. .) May occur. Such a large roughness region is only formed around the opening of the via hole. However, when a via hole having a small diameter (especially, the top diameter on the surface of the insulating layer is 40 μm or less) is employed, a fine region corresponding to that is used. Since the circuit wiring is formed around the via hole, the influence of the large roughness region becomes so large that it cannot be ignored. Therefore, when manufacturing a circuit board having a small-diameter via hole using a technique of performing a desmear process with the support attached to the insulating layer, the size of the large roughness region generated around the opening of the via hole may be reduced. A technology that can be used is desired.

  An object of the present invention is to manufacture a circuit board having a small-diameter via hole by using a technique of performing a desmear process in a state where a support is attached to an insulating layer. It is to provide technology that can be reduced.

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

That is, the present invention includes the following contents.
[1] (A) A resin sheet with a support including a plastic film support and a resin composition layer bonded to the plastic film support is attached to the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate. Laminating process,
(B) a step of thermosetting the resin composition layer to form an insulating layer, wherein the adhesion strength between the insulating layer and the plastic film support is 2 to 18 gf / cm,
(C) a step of irradiating a laser from above the plastic film support to form a via hole having a top diameter of 40 μm or less in the insulating layer;
(D) a step of performing a desmear process;
(E) The process of peeling a plastic film support body, (F) The manufacturing method of a circuit board including the process of forming a conductor layer in the surface of an insulating layer in this order.
[2] The method according to [1], wherein the desmear treatment in the step (D) is a wet desmear treatment.
[3] Step (F)
The method according to [1] or [2], comprising dry plating on the surface of the insulating layer to form a metal layer, and wet plating on the surface of the metal layer to form a conductor layer 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 includes an epoxy resin, a curing agent, and an inorganic filler.
[6] The method according to [5], wherein the inorganic filler has an average particle size of 0.01 μm to 3 μm.
[7] The method according to [5], wherein the inorganic filler has an average particle size of 0.01 μm to 0.4 μm.
[8] The content of the inorganic filler in the resin composition layer is 40% by mass to 95% by mass when the nonvolatile component in the resin composition layer is 100% by mass. [5] to [7] The method in any one of.
[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,
A circuit board in which the length of the large roughness region around the opening of the via hole on the surface of the insulating layer is less than 10 μm.
[12] The circuit board according to [11], wherein the arithmetic average roughness Ra of the insulating layer surface is 200 nm or less.
[13] A semiconductor device including the circuit board according to any one of [10] to [12].

  According to the present invention, when manufacturing a circuit board having a small-diameter via hole using a technique of performing a desmear process in a state where a support is attached to an insulating layer, the size of the roughness large region generated around the via hole opening is reduced. Can be reduced.

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

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

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

(Plastic film support)
Examples of the material for the plastic film support include polyesters such as polyethylene terephthalate (sometimes abbreviated as “PET”) and polyethylene naphthalate (sometimes abbreviated as “PEN”), and polycarbonate (“PC”). And acrylic such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, and the like. Among these, PET, PEN, and polyimide are preferable, and PET and PEN are more preferable. In one preferred 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 laser is irradiated from above the plastic film support to form a small diameter via hole. From the viewpoint of smoothly forming a via hole by laser irradiation, the plastic film support is preferably capable of absorbing laser energy. For example, since the PEN film support has ultraviolet (UV) absorption, it can be suitably used for forming via holes by UV irradiation.

  Laser energy absorptivity may be imparted or increased by incorporating a laser energy absorptive component into the plastic film support. The laser energy absorbing component is not particularly limited as long as it can absorb the laser used for forming the via hole, and examples thereof include carbon powder, metal compound powder, metal powder, and black dye. A laser energy absorption component may be used individually by 1 type, and may be used in combination of 2 or more type.

  Examples of the carbon powder include powders of carbon black such as furnace black, channel black, acetylene black, thermal black, anthracene black, graphite powder, and a mixture thereof. Examples of the metal compound powder include titania such as titanium oxide, magnesia such as magnesium oxide, iron oxide such as iron oxide, nickel oxide such as nickel oxide, zinc oxide such as manganese dioxide and zinc oxide, Silicon, aluminum oxide, rare earth oxide, cobalt oxide such as cobalt oxide, tin oxide such as tin oxide, tungsten oxide such as tungsten oxide, silicon carbide, tungsten carbide, boron nitride, silicon nitride, titanium nitride, aluminum nitride , Barium sulfate, rare earth oxysulfides, and mixtures thereof. 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. Examples thereof include powder. Examples of black dyes include azo (monoazo, disazo, etc.) dyes, azo-methine dyes, anthraquinone dyes, quinoline dyes, ketone imine dyes, fluorone dyes, nitro dyes, xanthene dyes, acenaphthene dyes, quinophthalone dyes, aminoketone dyes, methine dyes. Perylene dye, coumarin dye, perinone dye, triphenyl dye, triallylmethane dye, phthalocyanine dye, incrophenol dye, azine dye, and mixtures thereof. The black dye is preferably a solvent-soluble black dye in order to improve dispersibility. Among these, as the laser energy absorbing component, carbon powder is preferable from the viewpoint of conversion efficiency of laser energy to heat, versatility, and the like, and carbon black is particularly preferable. 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. The lower limit of the average particle diameter is preferably 0.001 μm or more, more preferably 0.002 μm, from the viewpoint of dispersibility. The “average particle diameter” as used herein can be measured by a particle size distribution measuring apparatus or BET method. The BET method is a method in which molecules having a known adsorption occupation area are adsorbed on the surface of powder particles at the temperature of liquid nitrogen, and the specific surface area of the sample is obtained from the amount. The average particle diameter can be calculated from the specific surface area determined by the BET method.

  The content of the laser energy-absorbing component is preferably 0.01% by mass or more, more preferably 0 from the viewpoint of smoothly forming a via hole when all components constituting the plastic film support are 100% by mass. 0.03 mass%, more preferably 0.05 mass% or more. The upper limit of the content is preferably 40% by mass or less, more preferably 20% by mass or less, and still more preferably 10% by mass or less from the viewpoint of obtaining a plastic film support having good flexibility. In addition, the laser energy absorptive component may be contained in the mold release layer mentioned later.

  Commercially available plastic film supports include, for example, “Lumirror R56”, “Lumirror R80”, “Lumirror T6AM” (PET film) manufactured by Toray Industries, Inc., and “G2LA” (PET) manufactured by Teijin DuPont Films Ltd. Film), "Teonex Q83" (PEN film), "Upilex-S" (polyimide film) manufactured by Ube Industries, Ltd., "Apical AH", "Apical NPI" (polyimide film) manufactured by Kaneka Corporation Can be mentioned.

  The plastic film support may be subjected to mat treatment or corona treatment on the surface to be bonded to the resin composition layer.

  Since it is easy to adjust the adhesion strength between the insulating layer and the plastic film support in a desired range in the step (B) described later, a release layer is provided on the surface to be bonded to the resin composition layer as the plastic film support. A plastic film support with a release layer having the following is preferred. Examples of the release agent used for the release layer include non-silicone release agents such as alkyd resins, melamine resins, olefin resins, and urethane resins, and silicone release agents. A mold release agent may be used individually by 1 type, and may be used in combination of 2 or more type. Among them, the release layer is a non-silicone release agent because it exhibits high wettability to the resin varnish when the resin sheet with a support is produced, and the contact state with the resin composition layer is likely to be uniform over the entire surface. A release layer containing is preferable, and a release layer containing an alkyd resin and / or an olefin resin is more preferable.

  The release agent is a so-called light release type release agent having a low peel strength, a so-called heavy release type release agent having a high peel strength, or a light release type release agent, depending on the type of constituent components. Can be classified as a so-called intermediate release type release agent that shows intermediate peel strength between the release agent and the heavy release type release agent, but it is easy to adjust the adhesion strength to a desired range in step (B). Mold release agents are preferred. Although it depends 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., the initial adhesive strength is preferable as the release agent. Is 100 (mN / 20 mm) or more, more preferably 300 (mN / 20 mm) or more, further 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 or 1000 (mN / 20 mm) or more release agent may be used. The upper limit of the initial adhesion strength is not particularly limited, but is usually 8000 (mN / 20 mm) or less, 7500 (mN / 20 mm) or less, etc. from the viewpoint that the plastic film support can be smoothly peeled in the step (E). obtain. The initial adhesion strength was determined by applying an acrylic adhesive tape (“31B” manufactured by Nitto Denko Corporation) using a 2 kg roller to the surface that had been subjected to a release treatment with a release agent, and letting it stand for 30 minutes. Can be obtained by measuring the load (mN / 20 mm) when it is peeled off and gripped with a gripper and peeled off at room temperature, at a speed of 30 cm / min, and at a peeling angle of 180 °. The measurement may be performed using, for example, a tensile tester such as “AC-50C-SL” manufactured by TSE Corporation.

  Examples of commercially available release agents include “X” (silicone-containing alkyd resin release agent; 490 mN / 20 mm) and “SK-1” (silicone-containing alkyd resin release agent) manufactured by Lintec Corporation. 1250 mN / 20 mm), “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 release agent: 4000 mN / 20 mm), and the like (the initial adhesion strength value is shown in parentheses). Commercially available release agents include “AL-7” (non-silicone alkyd resin release agent; heavy release type) manufactured by Lintec Corporation, and “NSP-4” manufactured by Fujimori Kogyo Co., Ltd. ( Non-silicone alkyd resin release agent; heavy release type).

  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, 20 μm to 50 μm is more preferable from the viewpoint of easy formation of a small diameter via. In addition, when a plastic film support body is a plastic film support body with a release layer, it is preferable that the thickness of the whole plastic film support body with a 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 has sufficient hardness and insulation and provides desired adhesion strength to the plastic film support. For example, a resin composition containing an epoxy resin, a curing agent, and an inorganic filler can be used. The resin composition used for the resin composition layer may further contain additives such as a thermoplastic resin, a curing accelerator, a flame retardant, and an organic filler as necessary.

-Epoxy resin-
Examples of the epoxy resin include bisphenol A type 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 novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type Epoxy resin, linear aliphatic epoxy resin, epoxy resin having butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing ester Carboxymethyl resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins and trimethylol type epoxy resins. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type.

  The epoxy resin preferably contains an epoxy resin having two or more epoxy groups in one molecule. When the nonvolatile component of the epoxy resin is 100% by mass, at least 50% by mass or more is preferably an epoxy resin having two or more epoxy groups in one molecule. Among them, it has two or more epoxy groups in one molecule, and has a liquid epoxy resin (hereinafter referred to as “liquid epoxy resin”) at a temperature of 20 ° C. and three or more epoxy groups in one molecule, It is preferable to contain a solid epoxy resin (hereinafter referred to as “solid epoxy resin”) at a temperature of 20 ° C. By using a liquid epoxy resin and a solid epoxy resin in combination as an epoxy resin, a resin composition having excellent flexibility can be obtained. Moreover, the breaking strength of the cured product of the resin composition is also improved.

  As the liquid epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, phenol novolac type epoxy resin, and epoxy resin having a butadiene structure are preferable, and bisphenol A type epoxy resin Bisphenol F type epoxy resin and naphthalene type epoxy resin are more preferable. Specific examples of the liquid epoxy resin include “HP4032”, “HP4032H”, “HP4032D”, “HP4032SS” (naphthalene type epoxy resin) manufactured by DIC Corporation, and “jER828EL” (bisphenol A) manufactured by Mitsubishi Chemical Corporation. Type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "ZX1059" (bisphenol A type epoxy resin and bisphenol F type epoxy resin manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.) ), “EX-721” (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation, and “PB-3600” (epoxy resin having a butadiene structure) manufactured by Daicel Chemical Industries, Ltd. . These may be used alone or in combination of two or more.

  Solid epoxy resins include naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, An anthracene type epoxy resin is preferable, and a naphthalene type tetrafunctional epoxy resin, a naphthol type epoxy resin, and a biphenyl type epoxy resin are more preferable. Specific examples of the solid epoxy resin include “HP-4700”, “HP-4710” (naphthalene type tetrafunctional epoxy resin), “N-690” (cresol novolac type epoxy resin) manufactured by DIC Corporation, “ N-695 ”(cresol novolac 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 novolac type epoxy resin),“ NC3000H ”,“ NC3000 ”, “NC3000L”, “NC3100” (biphenyl) Epoxy resin), “ESN475V” (naphthol type epoxy resin) manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., “ESN485V” (naphthol novolac type epoxy resin), “YX4000H”, “YL6121” (biphenyl type) manufactured by Mitsubishi Chemical Corporation Epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin), "PG-100", "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., Mitsubishi Chemical Corporation "YL7800" (fluorene type epoxy resin) manufactured by the same, etc. are mentioned.

  When the liquid epoxy resin and the solid epoxy resin are used in combination as the epoxy resin, the quantitative ratio thereof (liquid epoxy resin: solid epoxy resin) is in the range of 1: 0.1 to 1: 6 by mass ratio. preferable. By setting the quantity ratio of the liquid epoxy resin and the solid epoxy resin within such a range, i) suitable adhesiveness is obtained when used in the form of a resin sheet, ii) when used in the form of a resin sheet Sufficient flexibility is obtained, handling properties are improved, and iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the effects i) to iii) above, the quantitative ratio of liquid epoxy resin to solid epoxy resin (liquid epoxy resin: solid epoxy resin) is in the range of 1: 0.3 to 1: 5 by mass ratio. Is more preferable, and the range of 1: 0.6 to 1: 4.5 is even more preferable.

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

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

  The epoxy equivalent of the epoxy resin is preferably 50 to 3000, more preferably 80 to 2000, and still more preferably 110 to 1000. By becoming this range, the crosslinked density of hardened | cured material becomes sufficient and it can bring about an insulating layer with small surface roughness. The epoxy equivalent can be measured according to JIS K7236, and is the mass of a resin containing 1 equivalent of an epoxy group.

-Curing agent-
The curing agent is not particularly limited as long as it has a function of curing the epoxy resin. For example, a phenolic curing agent, a naphthol curing agent, an active ester curing agent, a benzoxazine curing agent, and a cyanate ester curing agent are included. Can be mentioned. 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, a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolak structure is preferable from the viewpoint of heat resistance and water resistance. Further, from the viewpoint of adhesion strength with the conductor layer, a nitrogen-containing phenol-based curing agent or a nitrogen-containing naphthol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent or a triazine skeleton-containing naphthol-based curing agent is more preferable. Among these, a triazine skeleton-containing phenol novolac resin is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion strength with the conductor layer. These may be used alone or in combination of two or more.

  Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, “MEH-7700”, “MEH-7810”, “MEH-7785” manufactured by Meiwa Kasei Co., Ltd., and Nippon Kayaku Co., Ltd. “NHN”, “CBN”, “GPH”, “SN-170”, “SN-180”, “SN-190”, “SN-475”, “SN-485”, “Tohto Kasei Co., Ltd.” SN-495 "," SN-375 "," SN-395 "," LA-7052, "" LA-7054, "" LA-3018, "" LA-1356, "etc. manufactured by DIC Corporation. .

  From the viewpoint of increasing the adhesion strength with the conductor layer, an active ester curing agent is also preferable. 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 ester, thiophenol ester, N-hydroxyamine ester, ester of heterocyclic hydroxy compound, are in 1 molecule. A compound having two or more in the above is preferably used. The active ester curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of 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 and 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, and m-cresol. P-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzene Examples include triol, dicyclopentadiene type diphenol compound, phenol novolac and the like. Here, the “dicyclopentadiene type diphenol compound” refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

  The active ester type curing agent includes 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 an active ester compound containing a benzoylated product of phenol novolac. Among them, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene type diphenol structure are more preferable. These may be used alone or in combination of two or more. The “dicyclopentadiene-type diphenol structure” represents a divalent structural unit composed of phenylene-dicyclopentalene-phenylene.

  As a commercial product of an active ester type curing agent, as an active ester compound containing a dicyclopentadiene type diphenol structure, “EXB9451”, “EXB9460”, “EXB9460S”, “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, and benzoyl of phenol novolac Examples of the active ester compound containing a compound include “YLH1026” (manufactured by Mitsubishi Chemical Corporation).

  Specific examples of the benzoxazine-based curing agent include “HFB2006M” manufactured by Showa Polymer Co., Ltd., “Pd” and “Fa” manufactured by Shikoku Kasei Kogyo Co., Ltd.

  Although it does not specifically limit as a cyanate ester type hardening | curing agent, For example, novolak type (phenol novolak type, alkylphenol novolak type, etc.) cyanate ester type hardening agent, dicyclopentadiene type cyanate ester type hardening agent, bisphenol type (bisphenol A type, And bisphenol F type, bisphenol S type, and the like) and cyanate ester-based curing agents, and prepolymers in which these are partially triazines. Specific examples include bisphenol A dicyanate, polyphenol cyanate (oligo (3-methylene-1,5-phenylene cyanate), 4,4′-methylenebis (2,6-dimethylphenyl cyanate), 4,4′-ethylidene diphenyl diester. Cyanate, hexafluorobisphenol A dicyanate, 2,2-bis (4-cyanate) phenylpropane, 1,1-bis (4-cyanatephenylmethane), bis (4-cyanate-3,5-dimethylphenyl) methane, , 3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bifunctional cyanate resins such as bis (4-cyanatephenyl) ether, phenol novolac and cresol novolac Derived from Polyfunctional cyanate resins, prepolymers in which these cyanate resins are partially triazine-modified, etc. Commercial products of cyanate ester-based curing agents include “PT30” and “PT60” manufactured by Lonza Japan K.K. Phenol novolac type polyfunctional cyanate ester resin), “BA230” (a prepolymer in which a part or all of bisphenol A dicyanate is triazine-modified into a trimer), and the like.

  From the viewpoint of improving the mechanical strength and water resistance of the resulting insulating layer, the amount ratio of the epoxy resin and the curing agent is a ratio of [total number of epoxy groups of epoxy resin]: [total number of reactive groups of curing agent]. The range of 1: 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 more preferable. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group or the like, and varies depending on the type of the curing agent. Moreover, the total number of epoxy groups of the epoxy resin is a value obtained by dividing the value obtained by dividing the solid 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 value obtained by dividing the solid mass of each curing agent by the reactive group equivalent is the total value for all curing agents.

-Inorganic filler-
The inorganic filler is not particularly limited. 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, phosphoric acid Zirconium, zirconium tungstate phosphate, etc. are mentioned. Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica is particularly suitable. As 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. Commercially available spherical fused silica includes “SOC2” and “SOC1” manufactured by Admatechs Co., Ltd.

  The average particle diameter of the inorganic filler is preferably 3 μm or less, more preferably 1 μm or less, further preferably 0.7 μm or less, and more preferably 0.5 μm or less from the viewpoint of obtaining an insulating layer on which fine circuit wiring can be formed. 0.4 μm or less, or 0.3 μm 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 from the viewpoint of obtaining a resin varnish having an appropriate viscosity and good handleability when forming a resin varnish using the resin composition, 0.03 μm or more is more preferable, 0.05 μm or more is further preferable, 0.07 μm or more is even more preferable, and 0.1 μm or more is particularly preferable. The average particle diameter of the inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis by a laser diffraction particle size distribution measuring device, and the median diameter can be measured as the average particle diameter. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction type particle size distribution measuring device, “LA-500”, “LA-750”, “LA-950”, etc. manufactured by Horiba, Ltd. can be used.

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

  In a preferred embodiment, an inorganic filler having an average particle diameter of 0.01 μm to 3 μm and particles having a particle diameter of 10 μm or more 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 further reducing the size of the large roughness area around the via hole opening. Examples of the surface treatment agent include an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an organosilazane compound, and a titanate coupling agent. A surface treating agent may be used individually by 1 type, and may be used in combination of 2 or more type. Examples of commercially available surface treatment agents include “KBM403” (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., and “KBM803” (3-mercaptopropyltrimethoxy manufactured by Shin-Etsu Chemical Co., Ltd.). Silane), Shin-Etsu Chemical "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical "SZ-31" (Hexamethyldisilazane) manufactured by Co., Ltd.

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 / m ² or more, more preferably 0.08 mg / m ² or more, more preferably 0.11 mg / ^{m 2} or more, even more preferably 0.14 mg / ^{m 2} or more, particularly preferably 0.17 mg / ^{m 2} or more, 0.20 mg / ^{m 2} or more, 0.23 mg / ^{m 2} or more, or 0. 26 mg / m ² or more. The upper limit of the carbon content is preferably 1.00 mg / ^{m 2} or less, more preferably 0.75 mg / ^{m 2} or less, more preferably 0.70 mg / ^{m 2} or less, even more preferably 0.65 mg / ^{m 2} or less , 0.60 mg / ^{m 2} or less, 0.55 mg / ^{m 2} or less, 0.50 mg / ^{m 2} or less.

  The amount of carbon per unit area bonded to the surface of the inorganic filler can be calculated by the following procedure. A sufficient amount of methyl ethyl ketone (MEK) as a solvent is added to the inorganic filler after the surface treatment, followed by ultrasonic cleaning. 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 amount of carbon by the specific surface area of the inorganic filler, the amount of carbon per unit surface area bonded to the inorganic filler is calculated. Examples of the carbon analyzer include “EMIA-320V” manufactured by HORIBA, Ltd.

  The content of the inorganic filler in the resin composition is 40% from the viewpoint of reducing the thermal expansion coefficient of the insulating layer and preventing the occurrence of cracks and circuit distortion due to the difference in thermal expansion between the insulating layer and the conductor layer. % Or more is preferable, 50 mass% or more is more preferable, and 60 mass% or more is more preferable. When an insulating layer is formed using a resin composition having a high inorganic filler content, the adhesion strength between the insulating layer and the conductor layer may be reduced. According to the method for manufacturing a circuit board of the present invention, Even when a resin composition having a high filler content is used, sufficient adhesion strength between the insulating layer and the conductor layer can be realized. In the method for producing a circuit board of the present invention, the content of the inorganic filler in the resin composition can be further increased without reducing the adhesion strength between the insulating layer and the conductor layer. For example, the content of the inorganic filler in the resin composition may be increased to 62 mass% or more, 64 mass% or more, 66 mass% or more, 68 mass% or more, or 70 mass% or more.

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

  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 liquid epoxy resin: solid epoxy resin is preferably 1: 0.1 to 1: 6, more preferably 1). : 0.3-1: 5, more preferably 1: 0.6-1: 4.5) as a curing agent, a phenolic curing agent, a naphthol curing agent, an active ester curing agent and a cyanate ester curing agent It is preferable that at least one selected from the group consisting of silica is included as an inorganic filler. Regarding the resin composition layer containing a combination of such specific components, the preferred content of the epoxy resin, the curing agent, and the inorganic filler is as described above, and among them, the content of the epoxy resin is 5% by mass. It is preferable that the content of the inorganic filler is 40% by mass to 95% by mass, the content of the epoxy resin is 10% by mass to 30% by mass, and the content of the inorganic filler is 50% by mass. More preferably, it is 90 mass%. Regarding the content of the curing agent, the ratio of the total number of epoxy groups of the epoxy resin and the total number of reactive groups of the curing agent is preferably included so as to be 1: 0.2 to 1: 2. It is more preferable to make it contain from 1: 0.3 to 1: 1.5, and it is still more preferred to make it contain from 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 curing accelerator, a flame retardant, and an organic filler as necessary.

-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, and polyether. Examples include ether ketone resins and polyester resins. A thermoplastic resin may be used individually by 1 type, or may be used in combination of 2 or more type.

  The weight average molecular weight in terms of polystyrene of the thermoplastic resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and still more preferably in the range of 20,000 to 60,000. The weight average molecular weight in terms of polystyrene of the thermoplastic resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-reduced weight average molecular weight 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 KK as a column. 804L / K-804L can be measured at a column temperature of 40 ° C. using chloroform or the like as a mobile phase, and can be calculated using a standard polystyrene calibration curve.

  Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene Examples thereof include phenoxy resins having a skeleton and one or more skeletons selected from the group consisting of a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. A phenoxy resin may be used individually by 1 type, and 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 resin), “YX8100” (bisphenol S skeleton-containing phenoxy resin), and “YX6954” (manufactured by Mitsubishi Chemical Corporation). In addition, “FX280” and “FX293” manufactured by Toto Kasei Co., Ltd., “YL7553”, “YL6794”, “YL7213” manufactured by Mitsubishi Chemical Corporation, YL7290 "," YL7482 ", etc. are mentioned.

  Specific examples of the polyvinyl acetal resin include electric butyral 4000-2, 5000-A, 6000-C, and 6000-EP manufactured by Denki Kagaku Kogyo Co., Ltd., and ESREC BH series and BX series manufactured by Sekisui Chemical Co., Ltd. KS series, BL series, BM series, etc. are mentioned.

  Specific examples of the polyimide resin include “Rika Coat SN20” and “Rika Coat PN20” manufactured by Shin Nippon Rika Co., Ltd. Specific examples of the polyimide resin include linear polyimide obtained by reacting a bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (described in JP-A-2006-37083), a polysiloxane skeleton. Examples thereof include modified polyimides such as containing polyimide (described in JP-A No. 2002-12667 and JP-A No. 2000-319386).

  Specific examples of the polyamide-imide resin include “Bilomax HR11NN” and “Bilomax HR16NN” manufactured by Toyobo Co., Ltd. Specific examples of the polyamideimide resin also include modified polyamideimides such as polysiloxane skeleton-containing polyamideimides “KS9100” and “KS9300” manufactured by Hitachi Chemical Co., Ltd.

  Specific examples of the polyethersulfone resin include “PES5003P” manufactured by Sumitomo Chemical Co., Ltd.

  Specific examples of the polysulfone resin include polysulfone “P1700” and “P3500” manufactured by Solvay Advanced Polymers Co., Ltd.

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

-Curing accelerator-
Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, phosphorus-based curing accelerators, amine-based curing accelerators, and imidazole-based accelerators. A curing accelerator is preferred. A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type. The content of the curing accelerator is preferably used in the range of 0.05% by mass to 3% by mass when the total of the nonvolatile components of the epoxy resin and the curing agent is 100% by 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. The content of the flame retardant in the resin composition is not particularly limited, but is preferably 0.5% by mass to 10% by mass, and more preferably 1% by mass to 9% by mass.

-Organic filler-
As the organic filler, any organic filler that can be used in forming the insulating layer of the circuit board may be used. Examples thereof include rubber particles, polyamide fine particles, and silicone particles, and rubber particles are preferable.

  The rubber particle is not particularly limited as long as it is a fine particle of a resin that has been subjected to a chemical crosslinking treatment on a resin exhibiting rubber elasticity and is insoluble and infusible in an organic solvent. For example, acrylonitrile butadiene rubber particles, butadiene rubber particles, Examples include acrylic rubber particles. Specific examples of rubber particles include XER-91 (manufactured by Nippon Synthetic Rubber Co., Ltd.), Staphyloid AC3355, AC3816, AC3816N, AC3832, AC4030, AC3364, IM101 (above, manufactured by Aika Industry Co., Ltd.) Paraloid EXL2655. , EXL2602 (manufactured by Kureha Chemical Industry Co., Ltd.) and the like.

  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 rubber particles can be measured using a dynamic light scattering method. For example, rubber particles are uniformly dispersed in an appropriate organic solvent by ultrasonic waves, etc., and the particle size distribution of the rubber particles is measured on a mass basis using a concentrated particle size analyzer (“FPAR-1000” manufactured by Otsuka Electronics Co., Ltd.). It can be measured by making the median diameter as an average particle diameter. The content of the rubber particles in the resin composition is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 5% by mass.

-Other ingredients-
The resin composition used for the resin composition layer may contain other components as necessary. Such other components include, for example, organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds, as well as thickeners, antifoaming agents, leveling agents, adhesion imparting agents, colorants, and curable resins. And the like, and the like.

  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, and even more preferably 50 μm or less, or 40 μm or less from the viewpoint of reducing the thickness of the circuit board. In particular, 30 μm or less is preferable, 20 μm or less is more preferable, and 15 μm or less is even more preferable from the viewpoint of easy formation of a small-diameter via. Although the minimum 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, the resin composition layer may have a multilayer structure composed of two or more layers. 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 can be produced by forming a resin composition layer on a plastic film support.

  The resin composition layer can be formed on a plastic film support by a 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 be provided.

  Solvents used for preparing the resin varnish include, for example, ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone, acetate solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve and Examples thereof include carbitol solvents such as butyl carbitol, aromatic hydrocarbon solvents such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone. A solvent may be used individually by 1 type and may be used in combination of 2 or more type.

  The coating film may be dried by a known drying method such as heating or hot air blowing. If a large amount of solvent remains in the resin composition layer, it may cause swelling after curing. Therefore, the resin composition layer is dried so that the amount of residual solvent in the resin composition is usually 10% by mass or less, preferably 5% by mass or less. . Depending on the boiling point of the organic solvent in the resin varnish, for example, when a resin varnish containing a solvent of 30% by mass to 60% by mass is used, the resin composition layer is dried at 50 ° C. to 150 ° C. for 3 to 10 minutes. Can be formed.

  In the resin sheet with a support, on the surface of the resin composition layer not joined to the plastic film support (that is, the surface opposite to the plastic film support), a protective film according to the plastic film support is further provided. Can be stacked. The thickness of the protective film is not particularly limited, and may be 1 μm to 40 μm, for example. By laminating the protective film, it is possible to prevent dust and the like from being attached to the surface of the resin composition layer and scratches. The resin sheet with a support can be wound and stored in a roll shape, and can be used by peeling off the protective film when manufacturing a circuit board.

[Circuit board manufacturing method]
The circuit board manufacturing method of the present invention includes the following steps (A) to (F) in this order.
(A) A step of laminating a resin sheet with a support including a plastic film support and a resin composition layer bonded to the plastic film support on the 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 adhesion strength between the insulating layer and the plastic film support is 2 to 18 gf / cm,
(C) a step of irradiating a laser from above the plastic film support to form a via hole having a top diameter of 40 μm or less in the insulating layer;
(D) a step of performing 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, “including in this order” for the steps (A) to (F) means that the steps (A) to (F) include the steps (A) to (F). As long as it is carried out in order, it does not preclude including other steps. Hereinafter, the same applies to “include in this order” for the steps or processes.

  When manufacturing a circuit board using a resin sheet with a support, the present inventors perform a desmear process with the support attached to the insulating layer, thereby achieving low roughness and a conductor layer. It has been found that an insulating layer with high adhesion strength can be formed. However, as described above, when the desmear process is performed in a state where the plastic film support is attached to the insulating layer, a region (“roughness region”) having a larger roughness than other regions is generated around the opening of the via hole. We have found that this is the case. Such a large roughness region is only formed around the opening of the via hole. However, when a via hole having a small diameter (especially, the top diameter on the surface of the insulating layer is 40 μm or less) is employed, a fine region corresponding to that is used. Since the circuit wiring is formed around the via hole, the influence of the large roughness region becomes so large that it cannot be ignored. In order to achieve a higher density of circuit wiring, a technique for reducing the size of the large roughness region generated around the opening of the via hole is required.

  In the process of studying the technique for reducing the size of the large roughness region generated around the opening of the via hole, the present inventors have determined the adhesion strength between the insulating layer formed through thermosetting and the plastic film support (ie, the process ( It has been found that the adhesive strength between the insulating layer obtained in B) and the plastic film support) affects the size of the large roughness region. And it discovered that the dimension of a large roughness area | region could be reduced by making this contact | adhesion intensity | strength more than predetermined value.

  1 and 2, two embodiments having different adhesion strengths between the insulating layer and the plastic film support are shown around the periphery of the via hole opening after the desmear treatment is performed with the plastic film support attached to the insulating layer. The scanning electron microscope (SEM) photograph of the surface of an insulating layer is shown. 1 and 2 are shown for reference, and are observed with respect to a via hole having a relatively large diameter (top diameter 50 μm).

FIG. 1 shows an SEM photograph of an embodiment (comparative embodiment) in which the adhesion strength between the insulating layer and the plastic film support is lower than the desired range (ie, 2 to 18 gf / cm) in the present invention. In FIG. 1, (a1) is an SEM photograph of the surface of the insulating layer around the via hole opening after desmear treatment, and (b1) is an SEM photograph showing the inside of the dotted line frame in (a1) in an enlarged manner. In the embodiment of FIG. 1, it is clearly confirmed that a region (roughness region) having a larger roughness than other regions is formed around the opening of the via hole. As understood from FIG. 1, the large roughness region is concentrically formed with the via hole so as to surround the via hole opening. In the present invention, the dimension of the large roughness region is evaluated by “the length of the large roughness region” (L _r ). This is because the radius r1 of the via hole opening (inner circle) and the outer edge of the large roughness region ( The difference (r2−r1) from the radius r2 of the outer circle). In the embodiment of FIG. 1, it is confirmed that the length (L _r ) of the large roughness region exceeds 10 μm.

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

  Hereinafter, each step will be described.

<Process (A)>
In the step (A), a resin sheet with a support including a plastic film support and a resin composition layer bonded to the plastic film support is attached to the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate. Laminate.

  The structure of the resin sheet with a support used in the step (A) is as described above. The “inner layer substrate” is mainly patterned on 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. A substrate on which a conductor layer (circuit) is formed. In addition, when the circuit board is manufactured, an inner layer circuit board as an intermediate product on which an insulating layer and / or a conductor layer is to be formed is also included in the “inner layer board” in the present invention.

  Lamination | stacking with the resin sheet with a support body and an inner layer board | 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. Examples of the member that heat-presses the resin sheet with a support to the inner layer substrate (hereinafter also referred to as “heat-pressing member”) include a heated metal plate (SUS mirror plate, etc.) or a metal roll (SUS roll). It is done. In addition, it is preferable not to press the thermocompression bonding member directly on the resin sheet with the support, but to press it through an elastic material such as heat-resistant rubber so that the resin composition layer sufficiently follows the surface irregularities of the inner substrate. .

  The thermocompression bonding temperature is preferably in the range of 80 ° C. to 160 ° C., more preferably 90 ° C. to 140 ° C., further preferably 100 ° C. to 120 ° C., and the thermocompression bonding pressure is preferably 0.098 MPa to 1.77 MPa, More preferably, it is in the range of 0.29 MPa to 1.47 MPa, and the thermocompression bonding time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination is preferably performed under reduced pressure conditions with a pressure of 26.7 hPa or less.

  Lamination can be performed with a commercially available vacuum laminator. Examples of the commercially available vacuum laminator include a vacuum pressure laminator manufactured by Meiki Seisakusho, a vacuum applicator manufactured by Nichigo Morton, and the like.

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

  After lamination, the laminated resin sheet with the support may be smoothed by pressing the thermocompression bonding member from the plastic film support side, for example, under normal pressure (atmospheric pressure). The pressing conditions for the smoothing treatment can be the same conditions as the thermocompression bonding conditions for the laminate. The smoothing treatment can be performed 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 the step (B), the resin composition layer is thermally cured to form an insulating layer. The step (B) is carried out so that the adhesion strength between the obtained insulating layer and the plastic film support is 2 to 18 gf / cm.

  From the viewpoint of reducing the size of the large roughness region generated around the opening of the via hole, the step (B) is preferably performed so that the adhesion strength between the obtained insulating layer and the plastic film support is 2 gf / cm or more. Is 2.5 gf / cm or more, more preferably 3 gf / cm or more, 3.5 gf / cm or more, 4 gf / cm or more, 4.5 gf / cm or more, or 5 gf / cm or more. If the adhesion strength is too high, when the plastic film support is peeled off in the step (E) described later, the plastic film support is cut off from the via hole, and a part of the plastic film support is formed on the surface of the insulating layer. Will remain. 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 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 section <Measurement of adhesion strength between the insulating layer and the plastic film support> below.

  In the step (B), the thermosetting conditions of the resin composition layer are not particularly limited as long as the desired adhesion strength is obtained. For example, the thermosetting conditions of the resin composition layer are in the range of 120 ° C. to 240 ° C. (preferably in the range of 150 ° C. to 210 ° C., depending on the type of plastic film support, the composition of the resin composition layer, etc. More preferably in the range of 160 ° C. to 200 ° C.) and 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). May be determined as appropriate. Moreover, the pressure at the time of thermosetting is not specifically limited, As long as the said desired adhesive strength is obtained, any of normal pressure, pressurization, and pressure reduction may be sufficient.

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

  By carrying out the step (B) so that the adhesion strength between the obtained insulating layer and the plastic film support falls within the above predetermined range, it is possible to reduce the size of the roughness large region generated around the via hole opening. Become.

<Process (C)>
In 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 (opening diameter on 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 more preferably 30 μm or less from the viewpoint of further increasing the density of the circuit wiring. Further preferred. According to the method of the present invention employing the above step (B), the size of the large roughness region generated around the via hole opening can be reduced, and even when a smaller diameter via hole is employed, it corresponds to that. Such fine circuit wiring can be formed around the via hole. In the method of the present invention, for example, a via hole having a top diameter of 28 μm or less, 26 μm or less, 24 μm or less, 22 μm or less, 20 μm or less, 18 μm or less, 16 μm or less, or 15 μm or less while maintaining good fine wiring formability. Can also be adopted. The lower limit of the top diameter of the via hole is not particularly limited, but can usually be 3 μm or more, 8 μm or more, and the like.

  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. Note that all the via holes formed in the step (C) do not have to have a top diameter of 40 μm or less. Depending on the design of the circuit board, a via hole having a top diameter exceeding 40 μm may be formed together.

In the step (C), examples of the laser light source include a carbon dioxide laser, a YAG laser, a UV-YAG laser, a YVO ₄ laser, a YLF laser, and an excimer laser. An appropriate laser light source may be used according to 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 small-diameter via hole can be formed, and may be appropriately determined according to the type of the laser light source, the thickness and the type of the plastic film support, and the insulating layer. Hereinafter, irradiation conditions when a carbon dioxide laser is used as the laser light source will be exemplified. When a carbon dioxide gas laser is used as the laser light source, laser light having a wavelength of 9.3 μm to 10.6 μm is generally used. The number of shots varies depending on the depth of the via hole to be formed and the top diameter, 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, it is preferable that the number of shots is smaller, preferably in the range of 1 to 5 shots, and more preferably in the range of 1 to 3 shots. Note that when the number of shots is two or more, the laser beam may be irradiated in either a burst mode or a cycle mode. The energy of the laser beam 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, and even more preferably 0.4 mJ or more. Is done. The upper limit of the energy of the laser beam is preferably 20 mJ or less, more preferably 15 mJ or less, and even more preferably 10 mJ or less.

  Step (C) may be performed using a commercially available laser device. As a commercially available laser device, for example, “LC-2E21B / 1C” (carbon dioxide laser device) manufactured by Hitachi Via Mechanics Co., Ltd., “605GTWIII (−P)” (carbon dioxide laser device) manufactured by Mitsubishi Electric Corporation, Examples thereof include “MODEL 5330xi” and “MODEL 5335” (UV-YAG laser apparatus) manufactured by ESI.

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

  Resin residues (smear) are generally attached to the inside of the via hole (particularly the bottom of the via hole) formed in the step (C). Since such smear causes a poor electrical connection between layers, a process of removing smear (desmear process) is performed in step (D).

  In the method for producing a circuit board according to the present invention, the desmear treatment is performed in a state where the plastic film support is attached to the insulating layer. Unlike the conventionally known technique in which the desmear treatment is performed after the support is peeled off, the surface of the insulating layer is protected by the plastic film support, so that the surface of the insulating layer is not roughened and the inside of the via hole is not roughened. Smear can be removed. In addition, since there is no restriction that the surface of the insulating layer is damaged, a wide range of desmear treatment methods and desmear treatment conditions can be employed. Thereby, when using the resin composition (for example, resin composition containing an active ester type hardening | curing agent) resulting in the resin residue (smear) which is hard to remove in a desmear process as a resin composition for forming an insulating layer Even so, it is possible to effectively remove smear without increasing the roughness of the surface of the insulating layer.

  As described above, when the desmear treatment is performed with the plastic film support attached to the insulating layer, the large roughness area around the opening of the via hole becomes a problem. However, the above specific step (B) is adopted. According to the method of the present invention, it is possible to reduce the size of the large roughness region generated around the opening of the via hole.

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

  Examples of the dry desmear process include a desmear process using plasma. Regarding the desmear treatment using plasma, it is known that the adhesion strength between the insulating layer and the conductor layer is likely to decrease due to surface modification of the insulating layer due to plasma. In the method of the present invention in which the desmear treatment is performed in the attached state, the desmear treatment can be advantageously performed without surface modification of the insulating layer.

  The desmear treatment using plasma can be performed using a commercially available plasma desmear treatment apparatus. Among commercially available plasma desmear treatment apparatuses, examples of suitable applications for the production of printed wiring boards include a microwave plasma apparatus manufactured by Nissin Co., Ltd. and an atmospheric pressure plasma etching apparatus manufactured by Sekisui Chemical Co., Ltd.

  As the dry desmear process, a dry sand blast process in which an abrasive is sprayed from a nozzle to polish the object to be processed may be used. The dry sand blast treatment can be carried out using a commercially available dry sand blast treatment apparatus. When a water-soluble abrasive is used as the abrasive, it is possible to effectively remove smear without leaving the abrasive in the via hole by washing with water after the dry sandblast treatment.

  Examples of the wet desmear process include a desmear process using an oxidant solution. When desmear treatment is performed using an oxidizing agent solution, it is preferable to perform a swelling treatment with a swelling liquid, an oxidation treatment with an oxidizing agent solution, and a neutralization treatment with a neutralizing solution in this order. Examples of the swelling liquid include “Swelling Dip Securigans P” and “Swelling Dip Securigans SBU” manufactured by Atotech Japan Co., Ltd. The swelling treatment is preferably performed by immersing the substrate on which the via hole is formed in a swelling liquid heated to 60 ° C. to 80 ° C. for 5 minutes to 10 minutes. The oxidant solution is preferably an aqueous alkaline permanganate solution, and examples thereof include a solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The oxidation treatment with the oxidant solution is preferably performed by immersing the substrate after the swelling treatment in an oxidant solution heated to 60 ° C. to 80 ° C. for 10 minutes to 30 minutes. Examples of commercially available alkaline permanganate aqueous solutions include “Concentrate Compact CP” and “Dosing Solution Securigans P” manufactured by Atotech Japan Co., Ltd. The neutralization treatment with the neutralization solution is preferably performed by immersing the oxidized substrate in a neutralization solution at 30 ° C. to 50 ° C. for 3 to 10 minutes. As the neutralizing solution, an acidic aqueous solution is preferable, and as a commercially available product, for example, “Reduction Solution Securigant P” manufactured by Atotech Japan Co., Ltd. can be mentioned.

  As the wet desmear process, a wet sand blast process in which an abrasive and a dispersion medium are sprayed from a nozzle to polish an object to be processed may be used. The wet sand blast treatment can be carried out using a commercially available wet sand blast treatment apparatus.

  When the dry desmear process and the wet desmear process are performed in combination, the dry desmear process may be performed first, or the wet desmear process may be performed first.

  In the wet desmear treatment, the present inventors have found that the size of the large roughness region generated around the opening of the via hole tends to increase, but the method of the present invention adopting the specific step (B) described above. Accordingly, even when wet desmearing is performed, it is possible to advantageously reduce the size of the large roughness region.

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

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

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

Since the surface of the insulating layer was protected by the plastic film support during the desmear treatment in the step (D), the surface of the insulating layer exposed in this step has a low roughness (about the roughness value of the insulating layer surface) Will be described later.) According to the method of the present invention, (it will be described later roughness large region of length L _r value) which can reduce the size of the roughness large region generated around the via hole opening advantageously. 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 the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer is one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Contains metal. The conductor layer may be a single metal layer or an alloy layer. As the alloy layer, for example, an alloy of two or more metals selected from the above group (for example, nickel-chromium alloy, copper- A layer formed from a nickel alloy and a copper / titanium alloy). Among them, from the viewpoint of versatility of conductor layer formation, cost, ease of patterning, etc., single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel / chromium alloy, copper / An alloy layer of nickel alloy or copper / titanium alloy is preferable, and a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or an alloy layer of nickel / chromium alloy is more preferable, and a single layer of copper is preferable. A metal layer is more preferred.

  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 nickel / chromium alloy.

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

In one embodiment, step (F) comprises
In this order, the surface of the insulating layer is dry-plated to form a metal layer, and the surface of the metal layer is wet-plated to form a conductor layer (hereinafter, these steps are referred to as “step (F-1 ) ").

  In the step (F-1), first, the surface of the insulating layer is dry-plated to form a metal 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 these two types of 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. The metal layer may have a single layer structure or a multilayer structure. When the metal layer has a multilayer structure, the thickness of the entire metal layer is preferably in the above range.

  In the step (F-1), after forming the metal layer, the surface of the metal layer is wet-plated to form a conductor layer.

  A metal layer can be used as a plating seed layer, and wet plating can be performed by a semi-additive method to form a conductor layer having a desired pattern. Specifically, a mask pattern is formed on the plating seed layer (metal layer) to expose a part of the plating seed layer corresponding to a desired wiring pattern. A conductive layer is formed on the exposed plating seed layer by electrolytic plating, and then the mask pattern is removed. Thereafter, an unnecessary plating seed layer can be removed by etching or the like to form a conductor layer having a desired wiring pattern.

  When a small-diameter via hole is employed, fine circuit wiring corresponding to the via hole is formed around the via hole. However, if the size of the large roughness region generated around the opening of the via hole is large, it is difficult to remove the plating seed layer in the large roughness region when the unnecessary plating seed layer is removed by etching when forming the wiring pattern. When etching is performed under conditions that can sufficiently remove the plating seed layer in a large area, the dissolution of the wiring pattern becomes remarkable, and it becomes difficult to form fine circuit wiring around the via hole. In this regard, according to the method of the present invention adopting the above-mentioned specific step (B), the size of the roughness large area generated around the via hole opening can be remarkably reduced, so that it corresponds to the circumference of the small diameter via hole. Such a fine circuit wiring can be formed with a desired wiring pattern. Therefore, the method for manufacturing a circuit board according to the present invention significantly contributes to miniaturization and high density of circuit wiring.

In the step (F-1), sufficient adhesion strength between the insulating layer and the conductor layer can be achieved without roughening the surface of the insulating layer, but the surface of the insulating layer is roughened. May be. In this case, the step (F-1)
Roughening the surface of the insulating layer;
In this order, the surface of the insulating layer is dry-plated to form a metal layer, and the surface of the metal layer is wet-plated to form a conductor layer.

  Examples of the roughening treatment include dry roughening treatment and wet roughening treatment, and the roughening treatment may be performed by combining these.

  The dry roughening treatment can be performed in the same manner as the dry desmear treatment described above. The wet roughening treatment can be performed in the same manner as the wet desmear treatment described above. When the dry roughening treatment and the wet roughening treatment are performed in combination, the dry roughening treatment may be performed first, or the wet roughening treatment may be performed first. The roughening treatment is intended to roughen the exposed surface of the insulating layer, but has a certain effect on removing smear inside the via hole. Therefore, even when the step (D) is performed under mild conditions, it is possible to prevent smear from remaining.

In another embodiment, step (F) comprises
Roughening the surface of the insulating layer and wet plating on the surface of the insulating layer to form a conductor layer are included in this order (hereinafter, these steps are referred to as “step (F-2)”). .

  The roughening process is as described above.

  In the step (F-2), after roughening the surface of the insulating layer, the surface of the insulating layer is wet-plated to form a conductor layer.

  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 capable of reducing the size of the large roughness region generated around the opening of the via hole, a fine circuit wiring corresponding to the small diameter via hole is formed in a desired wiring pattern. be able to.

  The step (F-1) is preferable as the step (F) because the surface roughness of the obtained insulating layer is much lower and contributes to the finer and higher density of the circuit wiring.

[Circuit board]
The circuit board manufactured by the method of the present invention has a via hole having a top diameter of 40 μm or less, and has a small size in a large roughness region around the opening of the via hole.

In one embodiment, the circuit board of the present invention comprises:
Including 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 length (L _r ) of the high roughness region around the opening of the via hole on the surface of the insulating layer is less than 10 μm.

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

The length (L _r ) of the large roughness region around the via hole opening is preferably 8 μm or less, more preferably 6 μm or less, and even more preferably 5 μm or less from the viewpoint of forming fine circuit wiring around the via hole. 4 μm or less, 3 μm or less, or 2 μm or less. The lower limit of the length (L _r ) of the large roughness region is preferably as small as possible and may be 0 μm, but is usually 0.1 μm or more. Note that the arithmetic average roughness (Ra) of the large roughness 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) provided around the via hole opening so as to be electrically connected to the via hole is preferably 40 μm or less, more preferably 30 μm or less, and still more preferably 20 μm or less. In the circuit board of the present invention in which the size of the large roughness region around the via hole opening is small, a conductor layer having a smaller 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 provided around the via hole opening so as to be electrically connected to 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, 6 μm or less, Alternatively, it can be reduced to 4 μm or less. The lower limit of the line width is not particularly limited, but can usually be 1 μm or more.

  As described above, the circuit board formed by the method of the present invention is characterized in that the surface roughness of the insulating layer is low. For example, the arithmetic average roughness (Ra) and root mean square roughness (Rq) of the insulating layer surface are as follows. The following values of Ra and Rq are values measured for a region at a sufficient distance (preferably 100 μm or more) from the end of the via hole opening so that the influence of the large roughness region can be ignored.

  In the circuit board of the present invention, the arithmetic average roughness (Ra) of the insulating layer surface 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 100 nm or less, It is 90 nm or less, 80 nm or less, 70 nm or less, or 60 nm or less. The lower limit of the Ra value is not particularly limited, but may be 0.5 nm or more, 1 nm or more, etc., in order to stabilize the adhesion strength with the conductor layer. 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. The lower limit of the Rq value is not particularly limited, but may be 10 nm or more, 30 nm or more, etc. in order to stabilize the adhesion strength with the conductor layer. The arithmetic mean roughness (Ra) and root mean square roughness (Rq) of the insulating layer surface can be measured using a non-contact type surface roughness meter. As a specific example of the non-contact type surface roughness meter, “WYKO NT3300” manufactured by Becoins Instruments is cited.

  The circuit board produced by the method of the present invention has a sufficient adhesion strength (peeling strength) on the surface of the insulating layer, that is, preferably 0.4 kgf / cm, although the roughness of the surface of the insulating layer is low as described above. As described above, a conductor layer exhibiting 0.45 kgf / cm or more, more preferably 0.5 kgf / cm or more, and even more preferably 0.54 kgf / cm or more is provided. The higher the adhesion strength, the better, but generally the upper limit is 1.5 kgf / cm. The peel strength between the insulating layer and the conductor layer can be measured according to JIS C6481.

[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 for electrical products (for example, computers, mobile phones, digital cameras, and televisions) and vehicles (for example, motorcycles, automobiles, trains, ships, and aircrafts). .

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the following, “part” and “%” mean “part by mass” and “% by mass”, respectively, unless otherwise specified.

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

[Preparation of samples for measurement and evaluation]
(1) Ground treatment of inner layer circuit board Glass cloth base epoxy resin double-sided laminated board with inner layer circuit (copper foil thickness 18 μm, substrate thickness 0.3 mm, size 500 mm × 500 mm, “R5715ES” manufactured by Panasonic Corporation) ) Was etched by 1 μm with “CZ8100” manufactured by Mec Co., Ltd., and the copper surface was roughened.

(2) Lamination of resin sheet with support The protective film of the resin sheet with a support (size 494 mm x 494 mm) prepared in the following preparation example is peeled off, and a batch-type vacuum pressure laminator (manufactured by Nichigo Morton Co., Ltd., two-stage buildup) Laminator CVP700) was used to laminate the inner layer circuit board on both sides so that the resin composition layer was in contact with the inner layer circuit board. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less and then pressing the film at 100 ° C. and a pressure of 0.74 MPa for 30 seconds. Next, hot pressing was performed at 100 ° C. and a pressure of 0.5 MPa for 60 seconds.

(3) Curing of resin composition layer The laminated resin sheet with a support was heated at 100 ° C for 30 minutes and then at 170 ° C for 30 minutes, and the resin composition layer was thermally cured to form an insulating layer. The obtained substrate is referred to as “evaluation substrate A”.

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

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

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

  (C) Using a UV-YAG laser processing machine “MODEL5330xi” manufactured by ESI, a laser was irradiated from above the plastic film support to form a via hole having a top diameter (diameter) of 15 μm 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, Rep Rate: 60 kHz, Repetition: 15, and circle / punch mode.

(D) Using a CO ₂ laser processing machine “605GTWIII (-P)” manufactured by Mitsubishi Electric Corporation, irradiate the laser from the plastic film support to form a via hole with a top diameter (diameter) of 12 μm on the insulating layer. Formed. 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, a shot number of 3, and a cycle mode.

(5) Desmear treatment After forming the via hole, the desmear treatment was performed with the plastic film support attached to the insulating layer. In addition, as a desmear process, the following wet desmear process (Examples 1-3, Comparative Examples 1-2) and the dry-type desmear process (Example 4) were implemented.

Wet desmear treatment:
The substrate with the via holes formed thereon was swollen in a swelling solution (“Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd., an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 5 minutes, and then an oxidizing agent solution (Atotech Japan). “Concentrate Compact CP” manufactured by Co., Ltd., an aqueous solution of potassium permanganate concentration of about 6% and sodium hydroxide concentration of about 4%) at 80 ° C. for 20 minutes, and finally a neutralizing solution (Atotech Japan Co., Ltd.) It was immersed in “Reduction Solution Securigant P”, sulfuric acid aqueous solution) at 40 ° C. for 5 minutes, and then dried at 80 ° C. for 15 minutes.

Dry desmear treatment:
Using a vacuum plasma etching apparatus (100-E PLASMA SYSTEM manufactured by Tepla), a substrate with a via hole formed thereon was subjected to the conditions of O ₂ / CF ₄ (mixed gas ratio) = 25/75 and a degree of vacuum of 100 Pa. The treatment was performed for 5 minutes.

(6) Peeling of plastic film support After the desmear treatment, the plastic film support was peeled according to the following procedure to expose the surface of the insulating layer. First, with respect to one end of the substrate 4 after the desmear treatment, a peeling part was formed by pressing a vibration pen from the plastic film support. The peeling part was pinched by hand, and the plastic film support was peeled off at once in the diagonal direction of the substrate. The obtained substrate is referred to as “evaluation 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 substrate is referred to as “evaluation substrate C”. In addition, the following dry process is equivalent to the above-mentioned process (F-1).
Dry method:
After the evaluation substrate B was heated at 150 ° C. for 30 minutes, a sputtering apparatus (“E-400S” manufactured by Canon Anelva Co., Ltd.) was used to form a titanium layer (thickness 30 nm) on the insulating layer, and then a copper layer (thickness). 300 nm) and a plating seed layer was provided. Next, an etching resist was formed according to a semi-additive method, and after forming a mask pattern by exposure and development, copper sulfate electrolytic plating was performed to form a conductor layer (thickness 25 μm). After removing the mask pattern, an unnecessary plating seed layer was removed by etching (copper etching solution: SAC manufactured by JCU Co., Ltd., titanium etching solution: Ryoko Chemical Co., Ltd. WLC-T) to form a conductor pattern. The obtained substrate was annealed at 190 ° C. for 60 minutes.

<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 for the evaluation substrate A according to the following procedure. Evaluation board | substrate A was cut into the dimension of width 30mm and length 150mm so that it may become longitudinally long in the longitudinal direction (MD direction) of a plastic film support body. Next, a cut was made with a cutter in a dimension of 15 mm in width and 100 mm in length from the plastic film support side. One end of the plastic film support is peeled off from the insulating layer and is gripped with a gripper. The load is measured when the plastic film support is peeled off 30 mm in the vertical direction at room temperature (23 ° C.) at a speed of 50 mm / min. The strength was determined. For the measurement, a tensile testing machine (“AC-50C-SL” manufactured by TSE Co., Ltd.) was used.

<2. Evaluation of peelability of plastic film support>
For the evaluation substrate B, the peelability of the plastic film support was evaluated. Observation was made on both surfaces (that is, all 10 surfaces) of the five evaluation substrates B to determine whether or not the plastic film support remained. And peelability was evaluated according to the following criteria. If the evaluation is “x”, the subsequent 3. To 6. Evaluation of was not carried out.
Evaluation criteria:
○: Residue of plastic film support is not observed on all surfaces. ×: Residue of plastic film support is recognized on more than one surface.

<3. Evaluation of dimensions of large roughness area>
About evaluation board | substrate B, the periphery of a via-hole opening part was observed with the scanning electron microscope (SEM), and the length ( _Lr ) of the roughness large area | region around a via-hole opening part was measured from the obtained image. The length (L _r ) of the large roughness region is the difference (r2−r1) between the radius r1 of the via hole opening (inner circle) and the radius r2 of the outer edge (outer circle) of the roughness large region. About 10 pieces of the via hole seeking L _r, to evaluate the size of the roughness large area according to the following criteria.
Evaluation criteria:
○: _Lr is less than 10 μm for all via holes ×: _Lr is 10 μm or more for one or more via holes

<4. Measurement of arithmetic average roughness (Ra) and root mean square roughness (Rq)>
For the evaluation substrate B, using a non-contact type surface roughness meter ("WYKO NT3300" manufactured by BEIKO INSTRUMENTS Co., Ltd.), Ra values and Rq values are obtained according to numerical values obtained with a measurement range of 121 μm × 92 μm by a VSI contact mode, 50 × lens. Asked. It measured by calculating | requiring the average value of 10 points | pieces selected at random about the area | region 100 micrometers or more away from the via-hole opening edge part.

<5. Measurement of adhesion strength between insulating layer and conductor layer>
The peel strength between the insulating layer and the conductor layer was measured for the evaluation substrate C in accordance with JIS C6481. Specifically, a notch having a width of 10 mm and a length of 100 mm is made in the conductor layer of the evaluation substrate D, this one end is peeled off and is gripped with a gripper, and is vertically moved at a speed of 50 mm / min at room temperature. The load (kgf / cm) when 35 mm was peeled off was measured to determine the adhesion strength. For the measurement, a tensile testing machine (“AC-50C-SL” manufactured by TSE Co., Ltd.) was used.

<6. Evaluation of smear removability>
About the evaluation board | substrate B, the circumference | surroundings of a via-hole bottom part were observed with the scanning electron microscope (SEM), and the maximum smear length from the wall surface of a via-hole bottom part was measured from the obtained image. The smear removability was evaluated according to the following criteria.
Evaluation criteria:
○: Maximum smear length is less than 3 μm ×: 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 Nippon Steel & Sumikin Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), bixylenol Type epoxy resin (epoxy equivalent of about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation), 10 parts of biphenyl type epoxy resin (epoxy equivalent of about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.), and phenoxy resin ( 10 parts “YL7553BH30” manufactured by Mitsubishi Chemical Corporation and 30 parts by mass of methyl ethyl ketone (MEK) solution were dissolved in 20 parts of solvent naphtha with stirring. After cooling to room temperature, 12 parts of a naphthol curing agent (hydroxyl equivalent 215, “SN-485” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., MEK solution with a solid content of 60%), triazine skeleton-containing phenol novolac curing 8 parts agent (hydroxyl equivalent 125, "LA-7054" manufactured by DIC Corporation, MEK solution with a solid content of 60%), curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 2% by mass) 4 parts, flame retardant (“HCA-HQ” manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle 2 parts of diameter (1 μm), 3 parts of rubber particles (“STAPHYLOID AC3816N” manufactured by Aika Kogyo Co., Ltd.), aminosilane coupling agent (“KBM57 manufactured by Shin-Etsu Chemical Co., Ltd.) Surface-treated spherical silica ") (Co. Admatechs Ltd." SOC1 ", average particle size 0.24 .mu.m, removing particles larger than 3μm by classification, per unit surface area of carbon amount 0.36 mg ^/ m 2) 90 Parts were mixed and dispersed uniformly with a high-speed rotary mixer to prepare resin varnish 1.

<Preparation Example 1> Production of Resin Sheet 1 with Support As a plastic film support, a PET film that has been subjected to release treatment with a heavy release non-silicone release agent (“NSP-4” manufactured by Fujimori Kogyo Co., Ltd.) “Toile Industries, Ltd.“ Lumilar T6AM ”, thickness 25 μm) was prepared. The resin varnish 1 was applied to the release surface of the plastic film support with a die coater and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 4 minutes to form a resin composition layer. The thickness of the resin composition layer was 20 μm. Next, a rough side of a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness: 15 μm) is attached as a protective film to the surface of the resin composition layer that is not bonded to the plastic film support. In addition, a resin sheet 1 with a support was obtained.

<Preparation Example 2> Preparation of Resin Sheet 2 with Support PEN film (Teijin DuPont) release-treated with a heavy release type silicone-containing release agent (“SK-1” manufactured by Lintec Corporation) as a plastic film support “Teonex Q83” manufactured by Film Co., Ltd., having a thickness of 25 μm) was prepared. The resin varnish 1 was applied to the release surface of the plastic film support with a die coater and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 3 minutes to form a resin composition layer. The thickness of the resin composition layer was 15 μm. Next, a rough side of a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness: 15 μm) is attached as a protective film to the surface of the resin composition layer that is not bonded to the plastic film support. In addition, a resin sheet 2 with a support was obtained.

<Preparation Example 3> Preparation of Resin Sheet 3 with Support PEN film (Teijin) subjected to release treatment with a heavy release non-silicone release agent (“AL-5” manufactured by Lintec Corporation) as a plastic film support A resin sheet 3 with a support was obtained in the same manner as in Production Example 2 except that “Teonex Q83” manufactured by DuPont Films Co., Ltd., and a thickness of 25 μm were used.

<Production Example 4> Production of resin sheet 4 with support PET film (Toray) treated as a plastic film support with a release-type non-silicone release agent ("AL-5" manufactured by Lintec Corporation). "Lumoror T6AM" manufactured by Co., Ltd., having a thickness of 50 µm) was prepared. The resin varnish 1 was applied to the release surface of the plastic film support with a die coater and dried at 80 ° C. to 110 ° C. (average 100 ° C.) for 2 minutes to form a resin composition layer. The thickness of the resin composition layer was 10 μm. Next, a rough side of a polypropylene film (“Alphan MA-411” manufactured by Oji Specialty Paper Co., Ltd., thickness: 15 μm) is attached as a protective film to the surface of the resin composition layer that is not bonded to the plastic film support. In addition, a resin sheet 4 with a support was obtained.

<Preparation Example 5> Preparation of Resin Sheet 5 with Support As a plastic film support, a PET film that has been release treated with a heavy release non-silicone release agent (“NSP-5” manufactured by Fujimori Kogyo Co., Ltd.) A resin sheet 5 with a support was obtained in the same manner as in Production Example 1 except that “Lumoror T6AM” manufactured by Toray Industries, Inc. was used.

<Preparation Example 6> Production of Resin Sheet 6 with Support As a plastic film support, a PEN film (Teijin DuPont film (Teijin DuPont Film) (Teijin DuPont film) that was subjected to release treatment with a heavy release type silicone-containing release agent (“6040” manufactured by Lintec Corporation). Resin sheet 6 with a support was obtained in the same manner as in Production Example 2 except that “Teonex Q83” manufactured by Co., Ltd. was used.

<Examples 1-4 and Comparative Examples 1 and 2>
As shown in Table 2, a circuit board was produced using the resin sheets 1 to 6 with a support according to the procedure of [Preparation of sample for measurement / evaluation]. Each evaluation result is shown in Table 2.

  In Comparative Example 1 where the adhesive strength between the heat-cured insulating layer and the plastic film support is as high as 19 gf / cm, when the plastic film support is peeled off, the plastic film support is cut off from the via hole as a starting point. It was confirmed that a part of the plastic film support remained on the surface of the layer (the plastic film support remained on four sides). In Comparative Example 2 where the adhesion strength was as low as 1 gf / cm, the size of the large roughness region generated around the opening of the via hole was large.

  On the other hand, in Examples 1 to 4 in which the adhesion strength between the heat-cured insulating layer and the plastic film support is in the range of 2 to 18 gf / cm, the size of the large roughness region generated around the via hole opening is significantly reduced. It was confirmed that In Examples 1 to 4, it was confirmed that an insulating layer having high adhesion strength with the conductor layer can be formed while having low roughness, and also exhibits excellent smear removability.

Claims (13)

(A) A step of laminating a resin sheet with a support including a plastic film support and a resin composition layer bonded to the plastic film support on the 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 adhesion strength between the insulating layer and the plastic film support is 2 to 18 gf / cm,
(C) a step of irradiating a laser from above the plastic film support to form a via hole having a top diameter of 40 μm or less in the insulating layer;
(D) a step of performing a desmear process;
(E) The manufacturing method of a circuit board including the process of peeling a plastic film support body, and the process of forming the conductor layer in the surface of (F) insulating layer in this order.   The method of Claim 1 that the desmear process of a process (D) is a wet desmear process. Step (F)
The method according to claim 1, comprising dry plating on the surface of the insulating layer to form a metal layer, and wet plating on the surface of the metal layer to form a conductor layer in this order.   The method according to any one of claims 1 to 3, wherein the plastic film support is a plastic film support with a release layer.   The method of any one of Claims 1-4 in which a resin composition layer contains an epoxy resin, a hardening | curing agent, and an inorganic filler.   The method of Claim 5 that the average particle diameter of an inorganic filler is 0.01 micrometer-3 micrometers.   The method of Claim 5 that the average particle diameter of an inorganic filler is 0.01 micrometer-0.4 micrometer.   The content of the inorganic filler in the resin composition layer is 40% by mass to 95% by mass when the nonvolatile component in the resin composition layer is 100% by mass. The method described in 1.   The method according to any one of claims 5 to 8, wherein the inorganic filler is surface-treated with a surface treatment agent.   The circuit board manufactured by the method of any one of Claims 1-9. A circuit board including 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,
A circuit board in which the length of the large roughness region around the opening of the via hole on the surface of the insulating layer is less than 10 μm.   The circuit board according to claim 11, wherein the arithmetic average roughness Ra of the surface of the insulating layer is 200 nm or less.   The semiconductor device containing the circuit board of any one of Claims 10-12.