JP7371606B2 - Manufacturing method of printed wiring board - Google Patents

Description

The present invention relates to a method for manufacturing a printed wiring board.

In recent years, in printed wiring boards, build-up layers have become multilayered, and there is a demand for finer wiring and higher density wiring. The build-up layer is formed by a build-up method in which insulating layers and conductor layers are stacked alternately. In the build-up manufacturing method, the insulating layer is generally formed by thermosetting a resin composition. It is.

Many proposals have been made for resin compositions suitable for forming the insulating layer of the inner layer circuit board, including, for example, the resin composition described in Patent Document 1.

JP 2017-59779 Publication

By the way, in manufacturing a printed wiring board, via holes are sometimes formed in an insulating layer. A "via hole" typically refers to a hole that passes through an insulating layer. One possible method for forming via holes is to use a laser.

When a via hole is formed using a laser, resin residue called smear may be formed in the via hole. In order to remove this smear, after the via hole is formed using a laser, a desmear process is usually performed to remove the smear using a chemical solution. The inventors of the present invention have discovered that heat is generated when laser is irradiated, and this heat is transmitted to the insulating layer and the underlying metal of the inner layer circuit board, thereby causing a haloing phenomenon. The haloing phenomenon refers to the occurrence of peeling between the insulating layer and the inner layer circuit board around the via hole. Such a haloing phenomenon usually occurs when the resin around the via hole is degraded by heat, and the degraded portion is eroded by a chemical solution such as a roughening solution. Note that the deteriorated portion is usually observed as a discolored portion.

Further, a method of suppressing the haloing phenomenon using sandblasting is considered, but it is difficult to form a small diameter via hole by sandblasting, and the processing speed of the via hole may be slow.

The present invention has been made in view of the above circumstances, and aims to provide a method for manufacturing a printed wiring board that can form small-diameter via holes, has excellent smear removal properties, and suppresses the occurrence of haloing. be.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have found that by forming an opening with a laser and then forming a via hole with sandblasting, it is possible to improve smear removal and suppress the haloing phenomenon. , we have completed the present invention.

That is, the present invention includes the following contents.
[1] (A) A step of forming an opening in an insulating layer containing a cured resin composition using a laser, and (B) A step of sandblasting the opening using abrasive grains to form a via hole. A method for manufacturing a printed wiring board, including in this order.
[2] The method for manufacturing a printed wiring board according to [1], wherein the abrasive grains have an average particle size of 10 μm or less.
[3] The method for manufacturing a printed wiring board according to [1] or [2], wherein the depth of the opening is 50% or more and 95% or less of the thickness of the insulating layer.
[4] Step (B) is a step of forming a via hole by colliding abrasive grains with the bottom surface of the opening through a mask,
The printed wiring according to any one of [1] to [3], wherein the ratio of the total value of the thickness of the mask and the depth of the opening to the opening diameter of the via hole (total value/opening diameter) is 3 or less. Method of manufacturing the board.
[5] The method for producing a printed wiring board according to any one of [1] to [4], wherein the insulating layer has an elastic modulus at 23° C. of 0.1 GPa or more.
[6] The method for producing a printed wiring board according to any one of [1] to [5], wherein the resin composition contains an inorganic filler.
[7] The method for manufacturing a printed wiring board according to [6], wherein the content of the inorganic filler is 20% by mass or more when the nonvolatile component in the resin composition is 100% by mass.
[8] The method for producing a printed wiring board according to any one of [1] to [7], wherein the resin composition contains a curable resin.
[9] The method for manufacturing a printed wiring board according to [8], wherein the content of the curable resin is 10% by mass or more when the nonvolatile component in the resin composition is 100% by mass.
[10] The method for manufacturing a printed wiring board according to [8] or [9], wherein the curable resin contains an epoxy resin and a curing agent.
[11] The method for manufacturing a printed wiring board according to [10], wherein the curing agent is one or more selected from phenolic resins, active ester resins, and cyanate ester resins.
[12] The method for manufacturing a printed wiring board according to any one of [1] to [11], wherein the laser is a CO ₂ laser or a UV-YAG laser.

According to the present invention, it is possible to provide a method for manufacturing a printed wiring board in which a small-diameter via hole can be formed, smear removal is excellent, and the occurrence of a haloing phenomenon is suppressed.

FIG. 1 is a schematic cross-sectional view showing an example of how an insulating layer and a support are formed on the main surface of an inner layer circuit board. FIG. 2 is a schematic cross-sectional view showing an example of the state after performing step (A). FIG. 3 is a schematic cross-sectional view showing an example of the state after performing step (B). FIG. 4 is a plan view schematically showing an insulating layer immediately before forming a conductor layer of a printed wiring board in which via holes are formed by conventional laser processing. FIG. 5 is a cross-sectional view schematically showing an insulating layer immediately before forming a conductor layer of a printed wiring board in which via holes are formed by conventional laser processing. FIG. 6 is a schematic cross-sectional view showing an example of how an insulating layer and metal foil are formed on the main surface of the inner layer circuit board. FIG. 7 is a schematic cross-sectional view showing an example of the state after pattern etching treatment is performed on the metal foil. FIG. 8 is a schematic cross-sectional view showing an example of the state after performing step (A). FIG. 9 is a schematic cross-sectional view showing an example of the state after performing step (B). FIG. 10 is a schematic cross-sectional view showing an example of the state after forming the filled via. FIG. 11 is a schematic cross-sectional view showing an example of how an insulating layer, metal foil, and dry film are formed on the main surface of the inner layer circuit board. FIG. 12 is a schematic cross-sectional view showing an example of the state after exposure and development. FIG. 13 is a schematic cross-sectional view showing an example of the state after performing step (A). FIG. 14 is a schematic cross-sectional view showing an example of the state after performing step (B). FIG. 15 is a schematic cross-sectional view showing an example of the state after forming the filled via. FIG. 16 is a schematic cross-sectional view showing an example of the state after removing the dry film. FIG. 17 is a schematic cross-sectional view showing an example of how an insulating layer and a dry film are formed on the main surface of the inner layer circuit board. FIG. 18 is a schematic cross-sectional view showing an example of the state after exposure and development. FIG. 19 is a schematic cross-sectional view showing an example of the state after performing step (A). FIG. 20 is a schematic cross-sectional view showing an example of the state after performing step (B). FIG. 21 is a schematic cross-sectional view showing an example of the state after forming the filled via.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples listed below, and may be implemented with arbitrary changes within the scope of the claims of the present invention and equivalents thereof.

Before explaining in detail the method for producing a printed wiring board of the present invention, the "resin composition" and "resin sheet with support" used in the method for producing a printed wiring board of the present invention will be explained.

[Resin composition]
The resin composition used to form the cured product may have sufficient hardness and insulation properties in the insulating layer that is the cured product. In one embodiment, the resin composition includes (a) an inorganic filler. The resin composition further contains (b) a curable resin, (c) a curing accelerator, (d) a thermoplastic resin, (e) an elastomer, and (f) other additives, as necessary. Good too. Each component contained in the resin composition will be explained in detail below.

<(a) Inorganic filler>
The resin composition contains (a) an inorganic filler. An inorganic compound is used as the material for the inorganic filler. Examples of inorganic filler materials include silica, alumina, aluminosilicate, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, and water. Aluminum oxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide , zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate. Among these, calcium carbonate and silica are preferred, and silica is particularly preferred. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica. Further, as the silica, spherical silica is preferable. (a) One type of inorganic filler may be used alone, or two or more types may be used in combination.

Commercial products of component (a) include, for example, "UFP-30" and "ASFP-20" manufactured by Denka; "SP60-05", "SP507-05" and "SPH516" manufactured by Nippon Steel Chemical & Materials. -05"; Admatex's "YC100C", "YA050C", "YA050C-MJE", "YA010C"; Tokuyama's "Silfill NSS-3N", "Silfill NSS-4N", "Silfill NSS-5N" "; "SC2500SQ," "SO-C4," "SO-C2," and "SO-C1" manufactured by Admatex.

The specific surface area of component (a) is preferably 1 m ² /g or more, more preferably 2 m ² /g or more, particularly preferably 3 m ² /g or more. Although there is no particular limit to the upper limit, it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area can be obtained by adsorbing nitrogen gas on the sample surface using a specific surface area measuring device (Macsorb HM-1210 manufactured by Mountec) according to the BET method, and calculating the specific surface area using the BET multi-point method. .

The average particle diameter of component (a) is preferably 0.01 μm or more, more preferably 0.05 μm or more, still more preferably 0.1 μm or more, from the viewpoint of significantly obtaining the desired effects of the present invention. It is 5 μm or less, more preferably 2 μm or less, even more preferably 1 μm or less.

The average particle size of component (a) can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, it can be measured by creating the particle size distribution of the inorganic filler on a volume basis using a laser diffraction scattering type particle size distribution measuring device, and using the median diameter as the average particle size. The measurement sample can be obtained by weighing 100 mg of the inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them using ultrasonic waves for 10 minutes. The measurement sample was measured using a laser diffraction particle size distribution measuring device using a light source wavelength of blue and red, and the volume-based particle size distribution of component (a) was measured using a flow cell method.The obtained particle size distribution The average particle size can be calculated as the median diameter. Examples of the laser diffraction particle size distribution measuring device include "LA-960" manufactured by Horiba, Ltd.

Component (a) is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of the surface treatment agent include vinyl silane coupling agents, (meth)acrylic coupling agents, fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, Examples include silane coupling agents, alkoxysilanes, organosilazane compounds, titanate coupling agents, and the like. Among these, from the viewpoint of significantly obtaining the effects of the present invention, vinylsilane coupling agents, (meth)acrylic coupling agents, and aminosilane coupling agents are preferred, and aminosilane coupling agents are more preferred. Moreover, one type of surface treatment agent may be used alone, or two or more types may be used in any combination.

Commercially available surface treatment agents include, for example, "KBM1003" (vinyltriethoxysilane) manufactured by Shin-Etsu Chemical, "KBM503" (3-methacryloxypropyltriethoxysilane) manufactured by Shin-Etsu Chemical, and "KBM503" (3-methacryloxypropyltriethoxysilane) manufactured by Shin-Etsu Chemical. "KBM403" (3-glycidoxypropyltrimethoxysilane), "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical , "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical, "KBM103" (phenyl trimethoxysilane), "KBM-4803" (long chain epoxy type silane coupling agent) manufactured by Shin-Etsu Chemical, "KBM-7103" (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical etc.

The degree of surface treatment with the surface treatment agent is preferably within a predetermined range from the viewpoint of improving the dispersibility of the inorganic filler. Specifically, 100 parts by mass of the inorganic filler is preferably surface-treated with 0.2 parts by mass to 5 parts by mass of a surface treatment agent, and preferably 0.2 parts by mass to 3 parts by mass. Preferably, the surface treatment is carried out in an amount of 0.3 parts by mass to 2 parts by mass.

The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. The amount of carbon per unit surface area of the inorganic filler is preferably 0.02 mg/m ² or more, more preferably 0.1 mg/m ² or more, and 0.2 mg/m ² from the viewpoint of improving the dispersibility of the inorganic filler. The above is more preferable. On the other hand, from the viewpoint of suppressing an increase in the melt viscosity of the resin varnish and the melt viscosity in sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and even more preferably 0.5 mg/m ² or less. preferable.

The amount of carbon per unit surface area of the inorganic filler can be measured after the surface-treated inorganic filler is washed with a solvent (for example, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler whose surface has been treated with a surface treatment agent, and the mixture is subjected to ultrasonic cleaning at 25° C. for 5 minutes. After removing the supernatant liquid and drying the solid content, the amount of carbon per unit surface area of the inorganic filler can be measured using a carbon analyzer. As the carbon analyzer, "EMIA-320V" manufactured by Horiba, Ltd., etc. can be used.

From the viewpoint of significantly obtaining the effects of the present invention, the content (mass%) of component (a) is preferably 20% by mass or more, more preferably 30% by mass when the nonvolatile components in the resin composition are 100% by mass. It is at least 40% by mass, more preferably at least 50% by mass, and preferably at most 95% by mass, more preferably at most 90% by mass, even more preferably at most 85% by mass, and at most 80% by mass. In the present invention, the content of each component in the resin composition is a value based on 100% by mass of nonvolatile components in the resin composition, unless otherwise specified.

From the viewpoint of significantly obtaining the effects of the present invention, the content (volume %) of component (a) is preferably 10 volume % or more, more preferably 10 volume % of the nonvolatile components in the resin composition. is 30% by volume or more, more preferably 50% by volume or more, preferably 90% by volume or less, more preferably 85% by volume or less, even more preferably 80% by volume or less.

<(b) Curable resin>
The resin composition may contain (b) a curable resin. (b) As the curable resin, a curable resin that can be used when forming an insulating layer of a printed wiring board can be used, and a thermosetting resin is preferable.

Examples of thermosetting resins include epoxy resins, phenol resins, naphthol resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins. Can be mentioned. Component (b) may be used alone or in combination of two or more in any ratio. The following resins are formed by reacting with epoxy resins, such as phenol resins, naphthol resins, benzoxazine resins, active ester resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins. Resins that can harden things are sometimes collectively referred to as "hardening agents." The resin composition preferably contains an epoxy resin and a curing agent as component (b) from the viewpoint of lowering the dielectric loss tangent.

(b) As the epoxy resin as the component, for example, bixylenol type epoxy resin, 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 novolac 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, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, glycidylcyclohexane type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin with a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring containing Examples include epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin, phenolphthalimidine type epoxy resin. One type of epoxy resin may be used alone, or two or more types may be used in combination.

It is preferable that the resin composition contains, as component (b), an epoxy resin having two or more epoxy groups in one molecule. From the viewpoint of significantly obtaining the desired effects of the present invention, the proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass with respect to 100% by mass of the nonvolatile components of component (b). The content is more preferably 60% by mass or more, particularly preferably 70% by mass or more.

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). ). The resin composition may contain only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin as component (b). good.

As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferable.

Liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolak type epoxy resin, and ester skeleton. Preferred are alicyclic epoxy resins, cyclohexane-type epoxy resins, cyclohexanedimethanol-type epoxy resins, glycidylamine-type epoxy resins, and epoxy resins having a butadiene structure, glycidylcyclohexane-type epoxy resins, and phenolphthalimidine-type epoxy resins. More preferred are A-type epoxy resin, glycidylcyclohexane-type epoxy resin, and phenolphthalimidine-type epoxy resin.

Specific examples of liquid epoxy resins include "HP4032", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC; "828US", "jER828EL", "825", and "Epicoat" manufactured by Mitsubishi Chemical Corporation. 828EL" (bisphenol A type epoxy resin); "jER807", "1750" (bisphenol F type epoxy resin) manufactured by Mitsubishi Chemical; "jER152" (phenol novolac type epoxy resin) manufactured by Mitsubishi Chemical; manufactured by Mitsubishi Chemical “630” and “630LSD” (glycidylamine type epoxy resin); “ZX1059” manufactured by Nippon Steel Chemical & Materials (mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin); manufactured by Nagase ChemteX Co., Ltd. "EX-721" (glycidyl ester type epoxy resin); Daicel's "Celoxide 2021P" (alicyclic epoxy resin with ester skeleton); Daicel's "PB-3600" (epoxy resin with butadiene structure) Examples include "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical & Materials. These may be used alone or in combination of two or more.

As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferable, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferable.

Solid epoxy resins include bixylenol type epoxy resin, naphthalene type epoxy resin, naphthalene type tetrafunctional epoxy resin, cresol novolak type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, and biphenyl. Type epoxy resins, naphthylene ether type epoxy resins, anthracene type epoxy resins, bisphenol A type epoxy resins, bisphenol AF type epoxy resins, and tetraphenylethane type epoxy resins are preferred, and biphenyl type epoxy resins, bixylenol type epoxy resins, and tetraphenyl type epoxy resins are preferred. Ethane type epoxy resin, naphthalene type epoxy resin, and naphthylene ether type epoxy resin are more preferred.

Solid epoxy resins include naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, Anthracene-type epoxy resins, bisphenol A-type epoxy resins, and tetraphenylethane-type epoxy resins are preferred, and naphthalene-type tetrafunctional epoxy resins, naphthol-type epoxy resins, and biphenyl-type epoxy resins are more preferred. Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin), "HP-4700", "HP-4710" (naphthalene type tetrafunctional epoxy resin), and "N-690" (manufactured by DIC). Cresol novolac type epoxy resin), "N-695" (Cresol novolac type epoxy resin), "HP-7200", "HP-7200HH", "HP-7200H" (dicyclopentadiene type epoxy resin), "EXA-7311" ", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); "EPPN-502H" manufactured by Nippon Kayaku Co., Ltd. Trisphenol type epoxy resin), “NC7000L” (naphthol novolac type epoxy resin), “NC3000H”, “NC3000”, “NC3000L”, “NC3100” (biphenyl type epoxy resin); “ESN475V” manufactured by Nippon Steel Chemical & Materials ” (naphthalene type epoxy resin), “ESN485” (naphthol novolac type epoxy resin); Mitsubishi Chemical's “YX4000H”, “YL6121” (biphenyl type epoxy resin), “YX4000HK” (bixylenol type epoxy resin), “ "YX8800" (anthracene type epoxy resin); "PG-100", "CG-500" manufactured by Osaka Gas Chemical Company, "YL7760" (bisphenol AF type epoxy resin), "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Co., Ltd. resin), “jER1010” (solid bisphenol A type epoxy resin), “jER1031S” (tetraphenylethane type epoxy resin); “WHR-991S” (phenolphthalimidine type epoxy resin) manufactured by Nippon Kayaku Co., Ltd. Can be mentioned. These may be used alone or in combination of two or more.

When using a combination of liquid epoxy resin and solid epoxy resin as component (b), their quantitative ratio (liquid epoxy resin: solid epoxy resin) is preferably 1:0.1 to 1: 20, more preferably 1:0.3 to 1:10, particularly preferably 1:0.5 to 1:5. When the ratio of the liquid epoxy resin to the solid epoxy resin is within this range, the desired effects of the present invention can be significantly obtained. Furthermore, when used in the form of a resin sheet with a support, appropriate tackiness is usually provided. Further, when used in the form of a resin sheet with a support, sufficient flexibility is usually obtained and handling properties are improved. Furthermore, it is usually possible to obtain a cured product having sufficient breaking strength.

The epoxy equivalent of the epoxy resin as component (b) is preferably 50 g/eq. ～5000g/eq. , more preferably 50g/eq. ～3000g/eq. , more preferably 80g/eq. ～2000g/eq. , even more preferably 110 g/eq. ～1000g/eq. It is. By falling within this range, a cured product of the resin composition can be provided with a sufficient crosslinking density. Epoxy equivalent is the mass of epoxy resin containing one equivalent of epoxy groups. This epoxy equivalent can be measured according to JIS K7236.

The weight average molecular weight (Mw) of the epoxy resin as component (b) is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500, from the viewpoint of significantly obtaining the desired effects of the present invention. be. The weight average molecular weight of the epoxy resin is the weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

From the viewpoint of obtaining a cured product exhibiting good mechanical strength and insulation reliability, the content of the epoxy resin as component (b) is preferably 1% by mass when the nonvolatile component in the resin composition is 100% by mass. The content is more preferably 3% by mass or more, still more preferably 5% by mass or more. The upper limit of the content of the epoxy resin is preferably 50% by mass or less, more preferably 45% by mass or less, particularly preferably 40% by mass or less, from the viewpoint of significantly obtaining the desired effects of the present invention.

As the active ester resin as component (b), a resin having one or more active ester groups in one molecule can be used. Among these, active ester resins include those having two or more ester groups with high reaction activity in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. Resins are preferred. The active ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. In particular, from the viewpoint of improving heat resistance, active ester resins obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester resins obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound are more preferred.

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 phenolic compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, Examples include benzenetriol, dicyclopentadiene type diphenol compounds, and phenol novolacs. Here, the term "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Preferred specific examples of active ester resins include active ester resins containing a dicyclopentadiene type diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing an acetylated product of phenol novolak, and benzoyl phenol novolac. Examples include active ester resins containing compounds. Among these, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene type diphenol structure are more preferable. "Dicyclopentadiene type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester resins include "EXB9451," "EXB9460," "EXB9460S," "HPC-8000-65T," and "HPC-8000H-" as active ester resins containing a dicyclopentadiene diphenol structure. 65TM", "EXB-8000L-65TM" (manufactured by DIC Corporation); "EXB9416-70BK", "EXB-8150-65T" (manufactured by DIC Corporation); an acetylated product of phenol novolak as an active ester resin containing a naphthalene structure; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing a benzoylated product of phenol novolac; "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing a benzoylated product of phenol novolak; "DC808" (manufactured by Mitsubishi Chemical); "YLH1026" (manufactured by Mitsubishi Chemical), "YLH1030" (manufactured by Mitsubishi Chemical), "YLH1048" (manufactured by Mitsubishi Chemical) as active ester resins that are benzoylated products of phenol novolak ); etc.

As the phenol resin and naphthol resin as component (b), those having a novolac structure are preferred from the viewpoint of heat resistance and water resistance. Further, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenolic curing agent is preferred, and a triazine skeleton-containing phenolic resin is more preferred.

Specific examples of phenolic resins and naphthol resins include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and "NHN" and "CBN" manufactured by Nippon Kayaku Co., Ltd. ", "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V", "SN375", "SN395" manufactured by Nippon Steel Chemical & Materials. , "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by DIC Corporation.

Specific examples of the benzoxazine resin as component (b) include "JBZ-OD100" (benzoxazine ring equivalent: 218), "JBZ-OP100D" (benzoxazine ring equivalent: 218), and "ODA-" manufactured by JFE Chemical Co., Ltd. BOZ” (benzoxazine ring equivalent 218); “P-d” (benzoxazine ring equivalent 217) manufactured by Shikoku Kasei Kogyo Co., “Fa” (benzoxazine ring equivalent 217); “HFB2006M manufactured by Showa Kobunshi Co., Ltd. (benzoxazine ring equivalent: 432).

Examples of the cyanate ester resin as component (b) include bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), and 4,4'-methylenebis(2,6-dimethylphenyl cyanate). ), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate) phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate- 3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether, etc. Bifunctional cyanate resins; polyfunctional cyanate resins derived from phenol novolacs, cresol novolacs, etc.; prepolymers in which these cyanate resins are partially triazine-formed; and the like. Specific examples of cyanate ester resins include "PT30", "PT30S" and "PT60" (phenol novolak type polyfunctional cyanate ester resin), "ULL-950S" (polyfunctional cyanate ester resin) manufactured by Lonza Japan, Examples include "BA230", "BA230S75" (a prepolymer in which part or all of bisphenol A dicyanate is triazinized to form a trimer), "BADCy" (bisphenol A dicyanate), and the like.

Specific examples of the carbodiimide resin as component (b) include Carbodilite (registered trademark) V-03 (carbodiimide group equivalent: 216), V-05 (carbodiimide group equivalent: 216), V-07 (carbodiimide group equivalent: 216), manufactured by Nisshinbo Chemical Co., Ltd. Carbodiimide group equivalent: 200); V-09 (carbodiimide group equivalent: 200); Stabaxol (registered trademark) P manufactured by Rhein Chemie (carbodiimide group equivalent: 302).

Examples of the amine resin as component (b) include resins having one or more amino groups in one molecule, such as aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. Examples include amines, among which aromatic amines are preferred from the viewpoint of achieving the desired effects of the present invention. The amine resin is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of the amine curing agent include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, and 3,3' - Diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl- 4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino-4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethane Diamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3- Bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, Examples include bis(4-(3-aminophenoxy)phenyl)sulfone. Commercially available amine resins may be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYA HARD AA", "KAYA HARD AB", and "KAYA HARD" manufactured by Nippon Kayaku Co., Ltd. Examples include "A-S" and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

Examples of the acid anhydride resin as component (b) include resins having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride resins include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, and hydrogenated methylnadic anhydride. trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride Acid, pyromellitic anhydride, bensophenonetetracarboxylic dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenyl Sulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1, Examples include polymeric acid anhydrides such as 3-dione, ethylene glycol bis(anhydrotrimellitate), and styrene-maleic acid resin, which is a copolymer of styrene and maleic acid.

As the curing agent as component (b), any one of phenol resin, naphthol resin, benzoxazine resin, active ester resin, cyanate ester resin, carbodiimide resin, amine resin, and acid anhydride resin can be used. is preferred, and any one of active ester resins, phenol resins, carbodiimide resins, and naphthol resins is preferred, and one or more selected from phenol resins, active ester resins, and cyanate ester resins. It is more preferable.

When containing an epoxy resin and a curing agent as components (b), the ratio of the epoxy resin to all curing agents is [total number of epoxy groups in the epoxy resin]:[total number of reactive groups in the curing agent]. The ratio is preferably in the range of 1:0.01 to 1:5, more preferably 1:0.1 to 1:3, and even more preferably 1:0.3 to 1:2. Here, "the number of epoxy groups in the epoxy resin" is the sum of all the values obtained by dividing the mass of nonvolatile components of the epoxy resin present in the resin composition by the epoxy equivalent. Moreover, "the number of active groups of a curing agent" is the total value of all the values obtained by dividing the mass of nonvolatile components of the curing agent present in the resin composition by the active group equivalent. By controlling the ratio of the epoxy resin and curing agent as component (b) within this range, a cured product with excellent flexibility can be obtained.

The content of the curing agent as component (b) is preferably 1% by mass or more, more preferably 3% by mass based on 100% by mass of the nonvolatile components in the resin composition, from the viewpoint of obtaining a cured product with excellent flexibility. % or more, more preferably 5% by mass or more, preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less.

In order to significantly obtain the effects of the present invention, the content of component (b) is preferably 10% by mass or more, more preferably 13% by mass or more, based on 100% by mass of the nonvolatile components in the resin composition. The content is preferably 15% by mass or more, preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.

<(c) Curing accelerator>
The resin composition may contain (c) a curing accelerator as an optional component. Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, etc. Curing accelerators are preferred, and amine curing accelerators are more preferred. The curing accelerator may be used alone or in combination of two or more.

Examples of the phosphorus curing accelerator include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate. , tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate and the like, with triphenylphosphine and tetrabutylphosphonium decanoate being preferred.

Examples of the amine curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo. Examples include (5,4,0)-undecene, and 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferred.

Examples of imidazole-based curing accelerators include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-Phenylimidazolium trimellitate, 2,4-diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-undecyl imidazolyl-(1')]-ethyl-s-triazine, 2,4-diamino-6-[2'-ethyl-4'-methylimidazolyl-(1')]-ethyl-s-triazine, 2,4- Diamino-6-[2'-methylimidazolyl-(1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline , 2-phenylimidazoline and other imidazole compounds, and adducts of imidazole compounds and epoxy resins, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

As the imidazole curing accelerator, commercially available products may be used, such as "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, Tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0] Dec-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylbiguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 -allylbiguanide, 1-phenylbiguanide, 1-(o-tolyl)biguanide, etc., and dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene are preferred.

Examples of the metal hardening accelerator include organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. Examples include organic zinc complexes such as , organic iron complexes such as iron (III) acetylacetonate, organic nickel complexes such as nickel (II) acetylacetonate, and organic manganese complexes such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

(c) The content of the curing accelerator is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, particularly preferably 0.02% by mass or more, when the nonvolatile components in the resin composition are 100% by mass. 03% by mass or more, preferably 3% by mass or less, more preferably 1% by mass or less, particularly preferably 0.5% by mass or less.

In addition, when the curing agent as component (b) is not included, the content of the curing accelerator (c) is preferably 0.01% by mass or more when the nonvolatile component in the resin composition is 100% by mass, The content is more preferably 0.02% by mass or more, particularly preferably 0.03% by mass or more, preferably 3% by mass or less, more preferably 1% by mass or less, particularly preferably 0.5% by mass or less.

<(d) Thermoplastic resin>
The resin composition may contain (d) a thermoplastic resin as an optional component. (d) Thermoplastic resins include, for example, phenoxy resin, polyvinyl acetal resin, polyolefin resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyether sulfone resin, polyphenylene ether resin, polyether ether ketone resin. , polyester resin, etc., with phenoxy resin being preferred. The thermoplastic resins may be used alone or in combination of two or more.

(d) The weight average molecular weight of the thermoplastic resin in terms of polystyrene is preferably 10,000 or more, more preferably 15,000 or more, and still more preferably 20,000 or more. The upper limit is preferably 100,000 or less, more preferably 70,000 or less, even more preferably 60,000 or less. (d) The weight average molecular weight of the thermoplastic resin in terms of polystyrene is measured by gel permeation chromatography (GPC). Specifically, (d) the weight average molecular weight of the thermoplastic resin in terms of polystyrene was determined using LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring device and Shodex K-800P/K-804L manufactured by Showa Denko Corporation as a column. /K-804L is 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 phenoxy resins 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, and terpene. Examples include phenoxy resins having one or more types of skeletons selected from the group consisting of a skeleton and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. One type of phenoxy resin may be used alone, or two or more types may be used in combination. Specific examples of phenoxy resins include Mitsubishi Chemical's "1256" and "4250" (both phenoxy resins containing bisphenol A skeleton), "YX8100" (phenoxy resin containing bisphenol S skeleton), and "YX6954" (bisphenol acetophenone). Other examples include "FX280" and "FX293" manufactured by Nippon Steel Chemical & Materials, "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30" manufactured by Mitsubishi Chemical Corporation, Examples include "YL7553BH30," "YL7769BH30," "YL6794," "YL7213," "YL7290," and "YL7482."

Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, Denka Butyral 6000-EP, manufactured by Denki Kagaku Kogyo Co., Ltd., and Sekisui. Examples include the S-LEC BH series, BX series (for example, BX-5Z), KS series (for example, KS-1), BL series, and BM series manufactured by Kagaku Kogyo Co., Ltd.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nihon Rika Co., Ltd. Specific examples of polyimide resins include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds, and tetrabasic acid anhydrides (polyimide described in JP-A No. 2006-37083), polysiloxane skeletons, etc. Examples include modified polyimides such as polyimides containing polyimides (polyimides described in JP-A-2002-12667 and JP-A-2000-319386, etc.).

Specific examples of the polyamide-imide resin include "Viromax HR11NN" and "Viromax HR16NN" manufactured by Toyobo. Specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical Co., Ltd.

A specific example of the polyether sulfone resin includes "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. Specific examples of the polyphenylene ether resin include oligophenylene ether styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Co., Ltd. Specific examples of polyetheretherketone resins include "Sumiploy K" manufactured by Sumitomo Chemical Co., Ltd., and the like. A specific example of the polyetherimide resin includes "Ultem" manufactured by GE.

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

Examples of polyolefin resins include ethylene copolymers such as low density polyethylene, ultra-low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer. Resin; Examples include polyolefin elastomers such as polypropylene and ethylene-propylene block copolymers.

Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, polycyclohexane dimethyl terephthalate resin, and the like.

Among them, as the thermoplastic resin (d), phenoxy resin and polyvinyl acetal resin are preferable. Therefore, in a preferred embodiment, the thermoplastic resin includes one or more selected from the group consisting of phenoxy resin and polyvinyl acetal resin. Among these, as the thermoplastic resin, phenoxy resin is preferable, and phenoxy resin having a weight average molecular weight of 10,000 or more is particularly preferable.

(d) The content of the thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and still more preferably 0.1% by mass or more, when the nonvolatile components in the resin composition are 100% by mass. It is 5% by mass or more. The upper limit is preferably 5% by mass or less, more preferably 4% by mass or less, even more preferably 3% by mass or less.

<(e) Elastomer>
The resin composition may include (e) an elastomer as an optional component in addition to the components described above. Component (e) may be used alone or in combination of two or more.

The component (e) is selected from polybutadiene structure, polysiloxane structure, poly(meth)acrylate structure, polyalkylene structure, polyalkyleneoxy structure, polyisoprene structure, polyisobutylene structure, polyester structure, and polycarbonate structure in the molecule. The resin preferably has one or more structures selected from polybutadiene structure, poly(meth)acrylate structure, polyalkyleneoxy structure, polyisoprene structure, polyester structure, or polycarbonate structure in the molecule. It is more preferable that the resin has one or more types of structures, and it is even more preferable that the resin has one of a polybutadiene structure, a polyester structure, and a polycarbonate structure in the molecule. Note that "(meth)acrylate" is a term that includes methacrylate, acrylate, and combinations thereof. These structures may be included in the main chain or in the side chain of the elastomer molecule.

Component (e) preferably has a high molecular weight from the viewpoint of significantly obtaining the effects of the present invention. The number average molecular weight (Mn) of component (e) is preferably 1,000 or more, more preferably 1,500 or more, even more preferably 3,000 or more, and even more preferably 5,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 900,000 or less. The number average molecular weight (Mn) is a polystyrene equivalent number average molecular weight measured using GPC (gel permeation chromatography).

Component (e) preferably has a low glass transition temperature (Tg) from the viewpoint of significantly obtaining the effects of the present invention. The glass transition temperature (Tg) of component (e) is preferably 30°C or lower, more preferably 20°C or lower, and still more preferably 10°C or lower. The temperature is preferably -60°C or higher, more preferably -50°C or higher, and even more preferably -45°C or higher.

Component (e) must have a functional group that can react with the epoxy resin as component (b), from the viewpoint of curing the resin composition and increasing peel strength by reacting with the epoxy resin as component (b). is preferred. Note that the functional groups that can react with the epoxy resin include functional groups that appear when heated.

In one preferred embodiment, the functional group capable of reacting with the epoxy resin as component (b) is selected from the group consisting of a hydroxy group, a carboxy group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, and a urethane group. One or more selected functional groups. Among these, the functional group is preferably a hydroxy group, an acid anhydride group, a phenolic hydroxyl group, an epoxy group, an isocyanate group, or a urethane group, and more preferably a hydroxy group, an acid anhydride group, a phenolic hydroxyl group, or an epoxy group. A hydroxyl group is particularly preferred. However, when containing an epoxy group as a functional group, the weight average molecular weight (Mw) of component (e) is preferably 5,000 or more.

A preferred embodiment of component (e) is a resin containing a polybutadiene structure, and the polybutadiene structure may be included in the main chain or in the side chain. Note that the polybutadiene structure may be partially or entirely hydrogenated. A resin containing a polybutadiene structure is called a polybutadiene resin.

Specific examples of polybutadiene resins include "Ricon 130MA8", "Ricon 130MA13", "Ricon 130MA20", "Ricon 131MA5", "Ricon 131MA10", "Ricon 131MA17", and "Ricon 131" manufactured by Clay Valley. MA20”, “Ricon 184MA6” (polybutadiene containing acid anhydride groups), “GQ-1000” manufactured by Nippon Soda Co., Ltd. (polybutadiene with hydroxyl and carboxyl groups introduced), “G-1000”, “G-2000”, “G-3000” (polybutadiene containing acid anhydride groups) hydroxyl group polybutadiene), “GI-1000”, “GI-2000”, “GI-3000” (hydrogenated polybutadiene with hydroxyl groups at both ends), “FCA-061L” manufactured by Nagase ChemteX (hydrogenated polybutadiene skeleton epoxy resin), etc. can be mentioned. In one embodiment, a linear polyimide made from a hydroxyl group-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimide described in JP2006-37083A and WO2008/153208), a phenolic hydroxyl group Containing butadiene and the like can be mentioned. The content of the butadiene structure in the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass. For details of the polyimide resin, the descriptions in JP-A No. 2006-37083 and International Publication No. 2008/153208 can be referred to, the contents of which are incorporated herein.

A preferred embodiment of component (e) is a resin containing a poly(meth)acrylate structure. A resin containing a poly(meth)acrylate structure is called a poly(meth)acrylic resin. Examples of poly(meth)acrylic resins include Teisan Resin manufactured by Nagase ChemteX, "ME-2000", "W-116.3", "W-197C", "KG-25", and "ME-2000" manufactured by Negami Kogyo Co., Ltd. KG-3000'', etc.

A preferred embodiment of component (e) is a resin containing a polycarbonate structure. A resin containing a polycarbonate structure is called a polycarbonate resin. Examples of polycarbonate resins include "T6002" and "T6001" (polycarbonate diol) manufactured by Asahi Kasei Chemicals, and "C-1090", "C-2090", and "C-3090" (polycarbonate diol) manufactured by Kuraray Corporation. It will be done. It is also possible to use linear polyimides made from hydroxyl-terminated polycarbonates, diisocyanate compounds, and tetrabasic acid anhydrides. The content of carbonate structure in the polyimide resin is preferably 60% by mass to 95% by mass, more preferably 75% by mass to 85% by mass. For details of the polyimide resin, the description in International Publication No. 2016/129541 can be referred to, the contents of which are incorporated herein.

Another embodiment of component (e) is a resin containing a polysiloxane structure. A resin containing a polysiloxane structure is called a siloxane resin. Examples of siloxane resins include "SMP-2006," "SMP-2003PGMEA," and "SMP-5005PGMEA" manufactured by Shin-Etsu Silicone, linear polyimides made from amine-terminated polysiloxanes and tetrabasic acid anhydrides (International Publication No. 2010/053185, JP 2002-12667, JP 2000-319386, etc.).

Another embodiment of component (e) is a resin containing a polyalkylene structure or a polyalkyleneoxy structure. A resin containing a polyalkylene structure is called a polyalkylene resin, and a resin containing a polyalkyleneoxy structure is called a polyalkyleneoxy resin. The polyalkyleneoxy structure is preferably a polyalkyleneoxy structure having 2 to 15 carbon atoms, more preferably a polyalkyleneoxy structure having 3 to 10 carbon atoms, and even more preferably a polyalkyleneoxy structure having 5 to 6 carbon atoms. Specific examples of polyalkylene resins and polyalkyleneoxy resins include "PTXG-1000" and "PTXG-1800" manufactured by Asahi Kasei Fibers.

Another embodiment of component (e) is a resin containing a polyisoprene structure. A resin containing a polyisoprene structure is called a polyisoprene resin. Specific examples of the polyisoprene resin include "KL-610" and "KL613" manufactured by Kuraray Co., Ltd.

Another embodiment of component (e) is a resin containing a polyisobutylene structure. A resin containing a polyisobutylene structure is called a polyisobutylene resin. Specific examples of polyisobutylene resins include "SIBSTAR-073T" (styrene-isobutylene-styrene triblock copolymer) and "SIBSTAR-042D" (styrene-isobutylene diblock copolymer) manufactured by Kaneka. .

A preferred embodiment of component (e) is a resin containing a polyester structure. A resin containing a polyester structure is called a polyester resin. Examples of polyester resins include "Byron 600", "Byron 560", "Byron 230", "Byron GK-360", and "Byron BX-1001" manufactured by Toyobo Co., Ltd., and "LP-035" and "Byron BX-1001" manufactured by Mitsubishi Chemical Corporation. Examples include ``LP-011'', ``TP-220'', ``TP-249'', and ``SP-185''.

(e) From the viewpoint of significantly obtaining the effects of the present invention, the content of the elastomer is preferably 5% by mass or more, more preferably 10% by mass or more, when the nonvolatile component in the resin composition is 100% by mass. More preferably, it is 15% by mass or more. The upper limit is preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less.

<(f) Other additives>
In addition to the above-mentioned components, the resin composition may further contain other additives as optional components. Such additives include, for example, flame retardants; organic fillers; organometallic compounds such as organocopper compounds, organozinc compounds, and organocobalt compounds; thickeners; antifoaming agents; leveling agents; adhesion imparting agents; Examples include resin additives such as colorants. These additives may be used alone or in combination of two or more in any ratio.

Examples of the flame retardant include phosphazene compounds, organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, metal hydroxides, and phosphazene compounds are preferred. One type of flame retardant may be used alone, or two or more types may be used in combination.

The phosphazene compound is not particularly limited as long as it is a cyclic compound containing nitrogen and phosphorus as constituent elements, but the phosphazene compound is preferably a phosphazene compound having a phenolic hydroxyl group.

Specific examples of phosphazene compounds include "SPH-100", "SPS-100", "SPB-100" and "SPE-100" manufactured by Otsuka Chemical Co., Ltd., "FP-100" manufactured by Fushimi Pharmaceutical Co., Ltd. Examples include "FP-110," "FP-300," and "FP-400," with "SPH-100" manufactured by Otsuka Chemical Co., Ltd. being preferred.

As the flame retardant other than the phosphazene compound, commercially available products may be used, such as "HCA-HQ" manufactured by Sankosha, "PX-200" manufactured by Daihachi Kagaku Kogyo Co., Ltd., and the like. The flame retardant is preferably one that is difficult to hydrolyze, such as 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide.

The content of the flame retardant is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0.3% by mass or more, when the nonvolatile components in the resin composition are 100% by mass. It is. The upper limit is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less.

As the organic filler, any organic filler that can be used when forming an insulating layer of a printed wiring board may be used, and examples thereof include rubber particles, polyamide fine particles, silicone particles, and the like. As the rubber particles, commercially available products may be used, such as "EXL2655" manufactured by Dow Chemical Japan, "AC3401N" and "AC3816N" manufactured by Aica Kogyo Co., Ltd., and the like. One type of organic filler may be used alone, or two or more types may be used in combination.

The content of the organic filler is preferably 0.1% by mass or more, more preferably 0.15% by mass or more, and even more preferably 0.2% by mass, when the nonvolatile components in the resin composition are 100% by mass. That's all. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less.

The method for preparing the resin composition is not particularly limited, and includes, for example, a method of mixing and dispersing the ingredients together with a solvent, if necessary, using a rotary mixer or the like.

[Resin sheet with support]
The resin sheet with a support includes a support and a resin composition layer formed of a resin composition provided on the support. The resin composition is as described in the [Resin composition] section.

The thickness of the resin composition layer is preferably 150 μm or less, more preferably 150 μm or less, from the viewpoint of making the printed wiring board thinner and providing a cured product with excellent insulation even if the cured product of the resin composition is a thin film. is 100 μm or less, more preferably 50 μm or less. The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 1 μm or more, 5 μm or more, etc.

Examples of the support include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferred.

When using a film made of a plastic material as a support, examples of the plastic material include polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"). ), polyesters such as polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethyl methacrylate (PMMA), cyclic polyolefins, triacetyl cellulose (TAC), polyether sulfide (PES), polyether Examples include ketones and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

When using metal foil as the support, examples of the metal foil include copper foil, aluminum foil, etc., with copper foil being preferred. As the copper foil, a foil made of a single metal such as copper may be used, or a foil made of an alloy of copper and other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. May be used.

The surface of the support to be bonded to the resin composition layer may be subjected to matte treatment, corona treatment, or antistatic treatment.

Further, as the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. . As the support with a release layer, commercially available products may be used, such as "SK-1", "AL-5", "AL-7" manufactured by Lintec, "Lumirror T60" manufactured by Toray Industries, Inc., and "Lumirror T60" manufactured by Teijin Corporation. Examples include PET films with a release layer containing an alkyd resin mold release agent as a main component, such as "Purex" manufactured by Co., Ltd. and "Unipeel" manufactured by Unitika; "U2-NR1" manufactured by DuPont Films; It will be done.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. In addition, when using the support body with a mold release layer, it is preferable that the thickness of the whole support body with a mold release layer is in the said range.

In one embodiment, the resin sheet with a support may further include other layers as necessary. Examples of such other layers include, for example, a protective film similar to the support provided on the surface of the resin composition layer that is not bonded to the support (i.e., the surface opposite to the support). It will be done. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, adhesion of dust and the like to the surface of the resin composition layer and scratches can be suppressed.

A resin sheet with a support can be produced by, for example, preparing a resin varnish by dissolving a resin composition in an organic solvent, applying this resin varnish onto a support using a die coater, and drying it to form a resin composition layer. It can be manufactured by forming.

Examples of organic solvents include ketones such as acetone, methyl ethyl ketone (MEK), and cyclohexanone; acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, and carbitol acetate; cellosolve and butyl carbitol, etc. carbitols; aromatic hydrocarbons such as toluene and xylene; and amide solvents such as dimethylformamide, dimethylacetamide (DMAc) and N-methylpyrrolidone. One type of organic solvent may be used alone, or two or more types may be used in combination.

Drying may be performed by a known method such as heating or blowing hot air. Although drying conditions are not particularly limited, drying is performed so that the content of organic solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less. Although it varies depending on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% to 60% by mass of organic solvent, the resin composition can be adjusted by drying at 50°C to 150°C for 3 to 10 minutes. A material layer can be formed.

The resin sheet with a support can be wound up into a roll and stored. When the resin sheet with a support has a protective film, it can be used by peeling off the protective film.

[Manufacturing method of printed wiring board]
The method for manufacturing a printed wiring board of the present invention includes:
(A) forming an opening in the insulating layer containing the cured resin composition using a laser; and (B) sandblasting the opening using abrasive grains to form a via hole in this order. Included in

As described above, a method using a laser can be considered as a method for forming via holes in an insulating layer. If a via hole is formed using only a laser, a haloing phenomenon may occur due to the heat generated by laser irradiation. In addition to the method of forming via holes using a laser, there is a method of forming via holes using sandblasting. If a via hole is formed only by sandblasting, the occurrence of the haloing phenomenon can be suppressed, but it is difficult to form a via hole with a small diameter, and the processing speed of the via hole may be slow.

In the present invention, first, an opening is formed in the insulating layer using a laser, and then a via hole is formed by colliding abrasive grains with the bottom surface of the opening by sandblasting, which makes it possible to form a small diameter via hole and improve smear removal. This makes it possible to suppress the occurrence of the haloing phenomenon. Furthermore, since the opening as a part of the via hole is formed using a laser and the entire via hole is not formed, the number of laser shots can be reduced. In addition, since the via hole is formed by sandblasting in the opening formed by laser, it is possible to suppress the deterioration of the resin around the bottom of the via hole, thereby suppressing the occurrence of the haloing phenomenon and shortening the processing time. (via processability).

Before performing step (A), the printed wiring board manufacturing method includes:
The method may include the following steps: (1) preparing an inner layer circuit board; and (3) forming an insulating layer on the main surface of the inner layer circuit board. In addition, in order to use it for forming the insulating layer in the step (3), the method for manufacturing a printed wiring board includes:
(2) preparing a resin sheet with a support, which includes a support and a resin composition layer formed of a resin composition provided on the support;
may further include. Each step of the printed wiring board manufacturing method will be described below.

<Step (1)>
Step (1) is a step of preparing an inner layer circuit board. The inner layer circuit board typically includes a support substrate and a metal layer provided on the surface of the support substrate. The metal layer is exposed on the main surface of the inner layer circuit board, and a via hole is formed in the area where the metal layer is located. Therefore, the area where the via hole is formed on the main surface of the inner layer circuit board is formed of a metal layer.

Examples of the material of the supporting substrate include a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, and the like. Examples of the material for the metal layer include copper foil, copper foil with a carrier, and materials for the conductor layer described below, with copper foil being preferred.

The arithmetic mean roughness (Ra) of the main surface of the inner layer circuit board is preferably 500 nm or less, more preferably 450 nm or less, still more preferably 400 nm or less, and 350 nm or less. By setting the arithmetic mean roughness (Ra) of the main surface of the inner layer circuit board to 500 nm or less, it is possible to prevent the insulating layer formed on the main surface from penetrating deep into the inner layer circuit board, improving the workability of via holes. can be done. The lower limit is not particularly limited, but is preferably 10 nm or more, more preferably 50 nm or more, and even more preferably 100 nm or more. The arithmetic mean roughness (Ra) of the main surface is a value measured in accordance with ISO 25178, and can be measured using a non-contact surface roughness meter. The main surface of the inner layer circuit board refers to the surface of the inner layer circuit board on which the insulating layer is provided.

In addition, if the arithmetic mean roughness (Ra) is not constant on the main surface, it is sufficient that the arithmetic mean roughness (Ra) of the main surface in the area where the metal layer is formed is within the above range, and via holes are formed. It is preferable that the arithmetic mean roughness (Ra) of the main surface in the area where it is applied is within the above range.

The ten-point average roughness (Rz) of the main surface of the inner layer circuit board is preferably 5000 nm or less, more preferably 4500 nm or less, still more preferably 4000 nm or less. By setting the ten-point average roughness (Rz) of the main surface of the inner layer circuit board to 5000 nm or less, it is possible to prevent the insulating layer formed on the main surface from penetrating deep into the inner layer circuit board, improving insulation reliability. can be done. The lower limit is not particularly limited, but is preferably 50 nm or more, more preferably 100 nm or more, and still more preferably 1000 nm or more. The ten-point average roughness (Rz) of the main surface is a value measured in accordance with ISO 25178, and can be measured using a non-contact surface roughness meter.

Further, when the ten-point average roughness (Rz) is not constant on the main surface, it is preferable that the ten-point average roughness (Rz) of the main surface in the area where the metal layer is formed is within the above range, It is more preferable that the ten-point average roughness (Rz) of the main surface in the area where the via hole is formed is within the above range.

The arithmetic mean roughness (Ra) and ten-point mean roughness (Rz) of the main surface of the inner layer circuit board can be adjusted to the above range by etching or polishing, for example.

<Step (2)>
Step (2) is a step of preparing a resin sheet with a support, which includes a support and a resin composition layer formed of a resin composition provided on the support. The resin sheet with support is as described above.

<Step (3)>
Step (3) is a step of forming an insulating layer on the main surface of the inner layer circuit board. In step (3), for example, a resin composition layer of a resin sheet with a support is laminated on the main surface of the inner layer circuit board, and the resin composition layer is thermally cured to form an insulating layer.

As an example is shown in FIG. 1, the inner layer circuit board 10 includes a support substrate 11 and a metal layer 12 provided on the surface of the support substrate 11. In step (3), a resin sheet with a support (not shown) is laminated on the main surface 10a of the inner circuit board 10, and the insulating layer 22 is formed by thermosetting the resin composition layer. Since the insulating layer 22 is usually provided on the surface of the metal layer 12, the surface of the metal layer 12 on the side opposite to the surface on the support substrate 11 side is the main surface 10a. Although the metal layer 12 is provided on one surface of the support substrate 11 in FIG. 1, it may be provided on both surfaces of the support substrate 11.

Lamination of the inner circuit board and the resin sheet with a support can be performed, for example, by heat-pressing the resin sheet with a support onto the inner circuit board from the support side. Examples of the member for hot-pressing the resin sheet with a support to the inner layer circuit board (hereinafter also referred to as "heat-pressing member") include a heated metal plate (SUS mirror plate, etc.) or a metal roll (SUS roll). Can be mentioned. Note that instead of pressing the thermocompression bonding member directly onto the resin sheet with a support, it is pressed through an elastic material such as heat-resistant rubber so that the resin sheet with a support sufficiently follows the surface irregularities of the inner layer circuit board. is preferred.

The inner layer circuit board and the resin sheet with support may be laminated by a vacuum lamination method. In the vacuum lamination method, the heat-pressing temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, and the heat-pressing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably 0. The pressure is in the range of .29 MPa to 1.47 MPa, and the heat-pressing time is preferably in the range of 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressure laminator manufactured by Meiki Seisakusho, a vacuum applicator manufactured by Nikko Materials, and a batch vacuum pressure laminator.

After lamination, the laminated resin sheets with a support may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression bonding member from the support side. The pressing conditions for the smoothing treatment can be the same as the conditions for the heat-pressing of the lamination described above. The smoothing process can be performed using a commercially available laminator. Note that the lamination and smoothing treatment may be performed continuously using the above-mentioned commercially available vacuum laminator.

After laminating the resin sheet with a support on the inner layer circuit board, the resin composition layer is thermally cured to form an insulating layer. The thermosetting conditions for the resin composition layer are not particularly limited, and conditions that are normally employed when forming an insulating layer of a printed wiring board may be used.

For example, the thermosetting conditions for the resin composition layer vary depending on the type of resin composition, etc., but the curing temperature is preferably 120°C to 240°C, more preferably 150°C to 220°C, and even more preferably 170°C to 210°C. It is ℃. The curing time can be preferably 5 minutes to 120 minutes, more preferably 10 minutes to 100 minutes, even more preferably 15 minutes to 100 minutes.

Before thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the resin composition layer, the resin composition layer is cured at a temperature of 50°C or higher and lower than 120°C (preferably 60°C or higher and 115°C or lower, more preferably 70°C or higher and 110°C or lower). Preheating may be performed for 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, even more preferably 15 minutes to 100 minutes).

The thickness of the insulating layer is 25 μm or less, preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, from the viewpoint of forming a small-diameter via hole. The lower limit of the thickness of the insulating layer is not particularly limited, but can usually be 1 μm or more, 5 μm or more, etc.

Note that in step (3), instead of using a resin sheet, a resin composition may be applied directly onto the main surface of the inner layer circuit board to form an insulating layer. The conditions for forming the insulating layer at this time are the same as those for forming the insulating layer using a resin sheet with a support.

The elastic modulus at 23°C of the insulating layer obtained by curing the resin composition layer at 200°C for 90 minutes is preferably 0.1 GPa or more, more preferably 1 GPa or more, and even more preferably 3 GPa or more, from the viewpoint of improving via processability. and is preferably 30 GPa or less, more preferably 25 GPa or less, even more preferably 20 GPa or less. The elastic modulus can be measured by the method described in Examples below.

The support may be removed after laminating the resin sheet with a support and before thermosetting, or after completing step (A), or after laminating and thermosetting the resin sheet with a support. Alternatively, it may be removed after being used as a mask in the sandblasting process in step (B).

<Process (A)>
Step (A) is a step of forming an opening in an insulating layer containing a cured resin composition using a laser. As an embodiment of step (A), as an example shown in FIG. 2, an opening 30 is formed by irradiating the insulating layer 22 formed on the main surface 10a of the inner layer circuit board 10 with a laser.

Laser irradiation is preferably performed with a mask for sandblasting treatment placed on the insulating layer 22. Therefore, step (A) may include the step of forming a mask on the insulating layer 22 before laser irradiation. Examples of the mask include dry film, metal foil, and combinations thereof. These masks can be provided on the insulating layer 22, for example, by laminating either a dry film or a metal foil onto the insulating layer after peeling off the support.

The dry film is preferably a patterned dry film that can be obtained by exposure and development, and more preferably a film that is resistant to sandblasting in step (B) described below. Further, as the dry film, a photosensitive dry film made of a photoresist composition can be used. As such a dry film, for example, a dry film formed of a resin such as a novolac resin or an acrylic resin can be used.

Examples of the metal foil include copper foil, aluminum foil, etc., with copper foil being preferred. As the copper foil, a foil made of a single metal such as copper may be used, or a foil made of an alloy of copper and other metals (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. May be used.

The thickness of the dry film mask is preferably 10 μm or more, more preferably 15 μm or more, even more preferably 20 μm or more, and preferably 100 μm or less, more preferably 70 μm or less, and Preferably it is 50 μm or less.

The thickness of the mask such as metal foil is preferably 1 μm or more, more preferably 2 μm or more, even more preferably 3 μm or more, and preferably 40 μm or less, more preferably 20 μm or less, from the viewpoint of improving the workability of the via hole. More preferably, it is 15 μm or less.

Moreover, the support body 21 may be used as a mask. When the support 21 is used as a mask, the process of providing a mask separate from the support 21 can be omitted, so the manufacturing method can be simplified. In this embodiment, as shown in FIG. 2, an example will be described in which the support body 21 is used as a mask.

The depth a of the opening is preferably at least 50% of the thickness of the insulating layer, more preferably at least 60%, even more preferably at least 70%, from the viewpoint of significantly obtaining the effects of the present invention. The upper limit is preferably 95% or less of the thickness of the insulating layer, more preferably 90% or less, still more preferably 85% or less. The depth of the opening refers to the distance from the surface of the insulating layer in contact with the mask (support 21 in FIG. 2) to the bottom of the opening. The depth of the opening can be determined by observing the cross section and calculating the difference between the deepest part of the unprocessed part and the processed part of the insulating layer.

The opening diameter b of the opening can be the opening diameter (via diameter) of a via hole. From the viewpoint of forming a small-diameter via hole, the opening diameter b is preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 55 μm or less, preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm. That's all. Note that the opening diameter b represents the diameter at the upper end of the insulating layer 22, as shown in FIG.

The ratio between the depth a of the opening and the diameter b of the opening (opening depth a/opening diameter b) is preferably 0.1 from the viewpoint of significantly obtaining the effects of the present invention. Above, it is more preferably 0.3 or more, still more preferably 0.5 or more, preferably 3 or less, more preferably 1 or less, and still more preferably 0.7 or less.

Examples of laser light sources that can be used to form the openings include CO ₂ laser (carbon dioxide laser), UV-YAG laser, UV laser, YAG laser, excimer laser, and the like. Among these, CO ₂ laser or UV-YAG laser is preferred from the viewpoint of processing speed and cost.

When irradiating with a CO ₂ laser, the number of shots is preferably 2 or less, more preferably 1, from the viewpoint of improving via processability. In order to keep the number of shots within the above range, it is preferable to set the energy and pulse width of the CO ₂ laser to a certain value or more. The energy of the CO ₂ laser is preferably 0.3 W or more, more preferably 0.5 W or more, even more preferably 1.0 W or more, and preferably 30 W or less, more preferably 20 W or less, and still more preferably 15 W or less. . Further, the pulse width of the CO ₂ laser is preferably 3 μsec or more, more preferably 5 μsec or more, even more preferably 8 μsec or more, and preferably 40 μsec or less, more preferably 30 μsec or less, and even more preferably 20 μsec or less.

When irradiating with UV-YAG laser, the number of shots is preferably 20 or less, more preferably 15 from the viewpoint of improving via processability. In order to keep the number of shots within the above range, it is preferable to set the energy and pulse width of the UV-YAG laser to a certain value or more. The energy of the UV-YAG laser is preferably 0.05 W or more, more preferably 0.10 W or more, even more preferably 0.15 W or more, and preferably 20 W or less, more preferably 10 W or less, and even more preferably 5 W or less. be.

Via holes can be formed using a commercially available laser device. Commercially available carbon dioxide laser devices include, for example, "LC-2E21B/1C" manufactured by Hitachi Via Mechanics, "ML605GTWII" manufactured by Mitsubishi Electric, and a substrate drilling laser processing machine manufactured by Matsushita Welding Systems. Furthermore, examples of the UV-YAG laser device include "LU-2L212/M50L" manufactured by Via Mechanics.

In step (A), as described above, it is preferable that the opening 30 be formed by irradiating the insulating layer 22 such as the support 21 with a mask provided with a laser. Therefore, preferably, the opening 30 is formed to communicate not only with the insulating layer 22 but also with the mask. Therefore, when the support 21 is used as a mask as in the example shown in FIG. 2, the opening 30 can be formed continuously in the insulating layer 22 and the support 21. In this case, the ratio (total value c/opening diameter) of the total value c of the thickness of the mask (thickness of the support 21 in FIG. From the viewpoint of significantly obtaining the effects of the present invention, the diameter is preferably 3 or less, more preferably 2.5 or less, even more preferably 2 or less, preferably 0.1 or more, more preferably 0.3 or more. , more preferably 0.5 or more. Here, the thickness of the mask refers to the thickness of the mask before performing step (B).

Further, the ratio (total value c/opening diameter b) of the total value c of the thickness of the mask and the depth a of the opening and the opening diameter b of the opening 30 before step (B) is the effect of the present invention. From the viewpoint of obtaining a significant amount of It is.

The total value c of the thickness of the mask and the depth of the opening is preferably 50% or more of the total thickness of the mask and the insulating layer, and more preferably 60% or more of the total thickness of the mask and the insulating layer. % or more, more preferably 70% or more. The upper limit is preferably 95% or less of the total thickness of the mask and the insulating layer, more preferably 90% or less, still more preferably 80% or less.

<Process (B)>
Step (B) is a step of sandblasting the opening using abrasive grains to form a via hole. As a detailed embodiment of step (B), a via hole is formed by colliding abrasive grains against the bottom surface of the opening through a mask. The mask is preferably at least one of a support with openings formed in step (A), a dry film, and a metal foil, and a support is more preferred.

As an example shown in FIG. 3, in step (B), a sandblasting process is performed to cause abrasive grains to collide with the bottom surface of the opening 30 to form a via hole 40. Here, sandblasting is a process in which abrasive grains or a slurry solution of abrasive grains are injected from a nozzle using air jetted at a predetermined pressure onto the surface of a support, dry film, or metal foil that is not covered with a mask. This process involves making the abrasive grains collide with the insulating layer to form via holes. The sandblasting process in step (B) may be either a dry blasting process in which abrasive grains are sprayed or a wet blasting process in which a slurry solution of abrasive grains is sprayed, but from the viewpoint of forming a small diameter via hole, wet blasting is preferable. It is preferable that there be.

The modified Mohs hardness of the abrasive grains used in sandblasting is preferably 1 or more, more preferably 5 or more, still more preferably 6 or more, and 7 or more, from the viewpoint of forming small diameter via holes by sandblasting. The upper limit value can usually be 15 or less. The modified Mohs hardness of the abrasive grain can be measured using, for example, a Mohs hardness meter.

Abrasive grains include inorganic compounds such as silica and glass; metal compounds such as steel, stainless steel, zinc, and copper; ceramics such as garnet, zirconia, silicon carbide, alumina, and boron carbide; particles whose main component is dry ice, etc. etc. Among these, inorganic compounds and ceramics are preferred, and any one of alumina, silicon carbide, and silica is preferred from the viewpoint of significantly obtaining the desired effects of the present invention. Silica is preferably crystalline silica.

Commercially available abrasive grains can be used. Commercially available products include, for example, "DAW-03" manufactured by Denka, "AY2-75" (alumina) manufactured by Nippon Steel Chemical &Materials;"GP#4000" and "SER-A06" (carbonized) manufactured by Shinano Electric Refining Co., Ltd. silicon); "IMSIL A-8" (crystalline silica) manufactured by Ryumori; and "Fujirandom WA" (fused alumina) manufactured by Fuji Seisakusho.

The average particle diameter of the abrasive grains is 0.5 μm or more, preferably 1 μm or more, and more preferably 2 μm or more. By setting the lower limit of the average grain size of the abrasive grains within this range, via processability can be improved. Further, it is possible to suppress blowback of abrasive grains during sandblasting, and it is possible to suppress grinding of the mask. Abrasive grain blowback is a phenomenon in which abrasive grains blown into an aperture reduce their collision speed due to the action of the airflow that enters the aperture and returns, and is particularly noticeable for abrasive grains with a small average grain size. be. The upper limit of the average particle diameter of the abrasive grains is 20 μm or less, preferably 15 μm or less, and more preferably 10 μm or less. By setting the upper limit of the average particle size of the abrasive grains within this range, the workability of small-diameter via holes can be improved. The average particle size of the abrasive grains can be measured, for example, by scanning electron microscopy, and the details can be measured by the method described in JP-A No. 2008-41932.

The pressure for injecting the abrasive grains (processing pressure) is preferably 0.05 MPa or more, more preferably 0.1 MPa or more, even more preferably 0.15 MPa or more, and preferably 1 MPa or less, more preferably 0.8 MPa or less. , more preferably 0.5 MPa or less. By controlling the processing pressure within this range, processing time can be shortened. The processing pressure here is the value at the surface of the insulating layer.

The distance between the nozzle and the mask is preferably 200 mm or less, more preferably 190 mm or less, even more preferably 180 mm or less, preferably 10 mm or more, more preferably 15 mm or more, still more preferably 20 mm or more. By setting the distance within this range, via holes can be formed efficiently.

By using the manufacturing method of the present invention, even if the top diameter of the via hole is small, the processing time for sandblasting can be shortened. The processing time is preferably less than 10 minutes, more preferably 8 minutes or less, even more preferably 5 minutes or less, and less than 5 minutes. The lower limit is not particularly limited, but may be 0.1 minute or more.

Although FIG. 3 shows an example in which the support 21 is used as a mask, either metal foil or dry film may be used as a mask instead of the support 21.

<Other processes>
When manufacturing a printed wiring board, after the step (B) is completed, (C) a step of roughening the insulating layer, and (D) a step of forming a conductor layer may be further carried out. These steps (C) and (D) may be carried out according to various methods used in the manufacture of printed wiring boards and known to those skilled in the art. Furthermore, if necessary, the formation of the insulating layer and conductive layer in steps (A) to (D) may be repeated to form a multilayer wiring board. Furthermore, the printed wiring board manufacturing method may include a step of removing the mask at an appropriate timing. Usually, the mask is removed after step (B) and before step (C).

Step (C) is a step of roughening the insulating layer (also referred to as desmear treatment). Usually, in this step (C), abrasive grains are also removed. The procedure and conditions for the roughening treatment are not particularly limited, and known procedures and conditions commonly used in forming an insulating layer of a printed wiring board can be adopted. For example, the insulating layer can be roughened by performing a swelling treatment using a swelling liquid, a roughening treatment using an oxidizing agent, and a neutralization treatment using a neutralizing liquid in this order. The swelling liquid used in the roughening treatment is not particularly limited, but includes alkaline solutions, surfactant solutions, etc., preferably alkaline solutions, and more preferably sodium hydroxide solutions and potassium hydroxide solutions. preferable. Examples of commercially available swelling liquids include "Swelling Dip Securigance P", "Swelling Dip Securigance SBU", and "Swelling Dip Securigant P" manufactured by Atotech Japan. It will be done. Swelling treatment with a swelling liquid is not particularly limited, but can be carried out, for example, by immersing the insulating layer in a swelling liquid at 30° C. to 90° C. for 1 minute to 20 minutes. From the viewpoint of suppressing the swelling of the resin in the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling liquid at 40° C. to 80° C. for 5 minutes to 15 minutes. The oxidizing agent used in the roughening treatment is not particularly limited, but includes, for example, an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganic acid solution is preferably performed by immersing the insulating layer in an oxidizing agent solution heated to 60° C. to 100° C. for 10 minutes to 30 minutes. Further, the concentration of permanganate in the alkaline permanganic acid solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan. Further, as the neutralizing liquid used for the roughening treatment, an acidic aqueous solution is preferable, and a commercially available product includes, for example, "Reduction Solution Securigant P" manufactured by Atotech Japan. The treatment with the neutralizing liquid can be carried out by immersing the treated surface, which has been roughened with an oxidizing agent, in the neutralizing liquid at 30° C. to 80° C. for 1 minute to 30 minutes. From the viewpoint of workability, it is preferable to immerse the object that has been roughened with an oxidizing agent in a neutralizing solution at 40° C. to 70° C. for 5 minutes to 20 minutes.

In one embodiment, the arithmetic mean roughness (Ra) of the surface of the insulating layer after the roughening treatment is preferably 500 nm or less, more preferably 400 nm or less, and still more preferably 300 nm or less. The lower limit is not particularly limited, but is preferably 30 nm or more, more preferably 40 nm or more, and still more preferably 50 nm or more. The arithmetic mean roughness (Ra) of the surface of the insulating layer can be measured using a non-contact surface roughness meter.

Step (D) is a step of forming a conductor layer, and the conductor layer is formed on the insulating layer. The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer includes 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, and the alloy layer may be, for example, an alloy of two or more metals selected from the above group (for example, a nickel-chromium alloy, a copper-chromium alloy, a copper-chromium alloy, etc.). nickel alloys and copper-titanium alloys). Among these, from the viewpoint of versatility in forming conductor layers, cost, ease of patterning, etc., monometallic layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, nickel-chromium alloys, copper, etc. An alloy layer of nickel alloy or copper/titanium alloy is preferable, 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 metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper is more preferable. More preferred is a metal layer.

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 depends on the desired printed wiring board design, but is generally between 3 μm and 35 μm, preferably between 5 μm and 30 μm.

In one embodiment, the conductor layer may be formed by plating. For example, a conductor layer having a desired wiring pattern can be formed by plating the surface of an insulating layer using a conventionally known technique such as a semi-additive method or a fully additive method. It is preferable to form by a method. An example of forming a conductor layer by a semi-additive method will be shown below.

First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer to expose a portion of the plating seed layer corresponding to a desired wiring pattern. After forming a metal layer on the exposed plating seed layer by electrolytic plating, the mask pattern is removed. Thereafter, unnecessary plating seed layers can be removed by etching or the like to form a conductor layer having a desired wiring pattern.

The method for manufacturing a printed wiring board of the present invention exhibits the characteristic that a small diameter via hole can be formed because the steps (A) and (B) are performed. The top diameter (via diameter) of the via hole is preferably 100 μm or less, more preferably 75 μm or less, even more preferably 55 μm or less, preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. The via diameter measurement method and details of the evaluation can be carried out by the method described in Examples described later.

The method for manufacturing a printed wiring board of the present invention exhibits excellent smear removability because the steps (A) and (B) are performed. Therefore, after a via hole is formed by the method of the present invention, if a desmear treatment is performed in which the via hole is immersed in a swelling liquid, a roughening liquid, and a neutralizing liquid in this order, no resin residue will be found at the bottom of the via hole. Evaluation of smear removability can be performed by the method described in the Examples described later.

The printed wiring board manufacturing method of the present invention exhibits the characteristic that the haloing phenomenon is suppressed. Specifically, even if the diameter of the via hole is within the above range and is small, the haloing phenomenon can be suppressed. The haloing phenomenon will be explained below with reference to the drawings.

FIG. 4 shows a surface 22U of the insulating layer 22, opposite to the metal layer 12 (not shown in FIG. 4), immediately before the conductor layer is formed, of a conventional printed wiring board in which via holes are formed with a laser. FIG. FIG. 5 is a cross-sectional view schematically showing the insulating layer 22 of a conventional printed wiring board in which via holes are formed by laser, just before the conductor layer is formed, together with the metal layer 12 of the inner layer circuit board. FIG. 5 shows a cross section of the insulating layer 22 taken along a plane that passes through the center 220C of the via bottom 220 of the via hole 40 and is parallel to the thickness direction of the insulating layer 22.

As shown in FIG. 5, when the via hole 40 is formed using a laser, a discolored portion 240 may occur due to deterioration of the resin due to the heat of the laser. This discolored portion 240 may be eroded by chemicals during the roughening treatment, and the insulating layer 22 may peel off from the metal layer 12, forming a gap 260 continuous from the edge 250 of the via bottom 220 (haloing phenomenon). .

In the present invention, after the opening is formed using a laser, a sandblasting process that does not easily generate heat is employed, so that deterioration of the resin can be suppressed. Therefore, peeling of the insulating layer 22 from the metal layer 12 can be suppressed, and the size of the gap 260 can be reduced.

The edge 250 of the via bottom 220 corresponds to the inner edge of the gap 260. Therefore, the distance Wb from the edge 250 of the via bottom 220 to the outer peripheral end of the gap 260 (that is, the end far from the center 220C of the via bottom 220) 270 is determined by the size of the gap 260 in the in-plane direction. Equivalent to. Here, the in-plane direction refers to a direction perpendicular to the thickness direction of the insulating layer 22. Further, in the following description, the distance Wb may be referred to as a harrowing distance Wb from the edge 250 of the via bottom 220 of the via hole 40. The degree of suppression of the haloing phenomenon can be evaluated based on the haloing distance Wb from the edge 250 of the via bottom 220. Specifically, it can be evaluated that the smaller the haloing distance Wb from the edge 250 of the via bottom 220 is, the more effectively the haloing phenomenon can be suppressed.

If the manufacturing method of the present invention is used, even if a via hole with a top diameter of 50 μm or less is formed, the harrowing distance Wb of the via hole 40 of the insulating layer 22 from the edge 250 of the via bottom 220 can be set to preferably 5 μm or less, more preferably The thickness can be 4 μm or less, more preferably 3 μm or less. The lower limit is not particularly limited, but may be 0 μm or more, 0.1 μm or more, etc.

The manufacturing method of the present invention can manufacture a printed wiring board having via holes and trenches, as an example shown in FIGS. 6 to 10. In detail, as an example is shown in FIG. 6, before performing step (A), an insulating layer 22 is formed on the inner layer circuit board 10, and a metal foil 60 is further laminated on the insulating layer 22. After laminating the metal foil 60, a pattern etching process is performed on the metal foil 60, as shown in an example in FIG. 7, and a part of the metal foil 60 is removed to form a hole 61. Thereafter, as an example shown in FIG. 8, a step (A) of irradiating a predetermined location of the metal foil 60 with a laser is performed to form the opening 30. Next, as shown in FIG. 9, a via hole 40 is formed from the opening 30 by performing step (B), and a trench 50 is formed by impinging abrasive grains on the bottom of the hole 61 by sandblasting. be done. Thereafter, as an example shown in FIG. 10, the via holes 40 and trenches 50 are filled by electrolytic plating to form filled vias 80. After forming the filled via 80, the metal foil 60 may be removed if necessary.
In addition, a metal foil is laminated on the resin composition layer of a resin sheet with a support to obtain a metal foil with a resin composition layer, the metal foil with a resin composition layer is laminated on an inner layer circuit board, and an insulating layer and a metal foil are formed on an inner layer. It may also be formed on a circuit board.

Further, the manufacturing method of the present invention can manufacture a printed wiring board having a patterned conductor layer, as an example shown in FIGS. 11 to 16. In detail, as an example is shown in FIG. 11, before performing step (A), an insulating layer 22 is formed on the inner layer circuit board 10, and a metal foil 60 and a dry film 70 are further laminated on the insulating layer 22. After laminating the metal foil 60 and the dry film 70, as shown in an example in FIG. 12, a part of the dry film 70 is exposed and developed to form a hole 71 in which a part of the dry film 70 is removed. Thereafter, as an example shown in FIG. 13, a step (A) of irradiating a predetermined portion of the dry film 70 with a laser is performed to form the opening 30. Next, a via hole 40 is formed from the opening 30 by performing step (B) as shown in an example in FIG. After completing step (B), as shown in an example in FIG. 15, the via holes 40 and holes 71 are filled by electrolytic plating to form filled vias 80, and the dry film (not shown) is removed as shown in FIG. 16. Then, a patterned conductor layer is formed. The metal foil 60 may be used as a plating seed layer for the electrolytic plating described above.
Before removing the dry film, the surface of the filled via 80 may be polished by buffing or the like in order to adjust the height of the filled via 80, if necessary.
In addition, a metal foil is laminated on the resin composition layer of a resin sheet with a support to obtain a metal foil with a resin composition layer, the metal foil with a resin composition layer is laminated on an inner layer circuit board, and an insulating layer and a metal foil are formed on an inner layer. It may also be formed on a circuit board.

The manufacturing method of the present invention can manufacture a printed wiring board having via holes and trenches, as an example shown in FIGS. 17 to 21. In detail, as an example is shown in FIG. 17, before performing step (A), an insulating layer 22 is formed on the inner layer circuit board 10, and a dry film 70 is further laminated on the insulating layer 22. After laminating the dry film 70, as an example shown in FIG. 18, a part of the dry film 70 is exposed and developed to form a hole 71 in which a part of the dry film 70 is removed. Thereafter, as an example shown in FIG. 19, a step (A) of irradiating a predetermined portion of the dry film 70 with a laser is performed to form the opening 30. Next, as shown in FIG. 20, a via hole 40 is formed from the opening 30 by performing step (B), and a trench 50 is formed by impinging abrasive grains on the bottom of the hole 71 by sandblasting. Ru. Thereafter, as an example shown in FIG. 21, the via holes 40 and trenches 50 are filled by electrolytic plating to form filled vias 80. After forming the filled via 80, the dry film 70 may be removed if necessary.
Before removing the dry film, the surface of the filled via 80 may be polished by buffing or the like in order to adjust the height of the filled via 80, if necessary.

[Semiconductor device]
The semiconductor device of the present invention includes a printed wiring board. The semiconductor device of the present invention can be manufactured using a printed wiring board obtained by the manufacturing method of the present invention.

Examples of semiconductor devices include various semiconductor devices used in electrical products (eg, computers, mobile phones, digital cameras, televisions, etc.), vehicles (eg, motorcycles, automobiles, trains, ships, aircraft, etc.), and the like.

The semiconductor device of the present invention can be manufactured by mounting components (semiconductor chips) on conductive parts of a printed wiring board. A "conducting location" is a "location on a printed wiring board that transmits electrical signals," and the location may be on the surface or embedded. Further, the semiconductor chip is not particularly limited as long as it is an electric circuit element made of a semiconductor.

The mounting method for semiconductor chips when manufacturing semiconductor devices is not particularly limited as long as the semiconductor chip functions effectively, but specifically, wire bonding mounting method, flip chip mounting method, bumpless buildup layer, etc. Examples include a mounting method using (BBUL), a mounting method using an anisotropic conductive film (ACF), a mounting method using a non-conductive film (NCF), and the like. Here, "a mounting method using a bumpless buildup layer (BBUL)" refers to a "mounting method in which a semiconductor chip is directly embedded in a recess of a printed wiring board and the semiconductor chip and wiring on the printed wiring board are connected." It is.

Hereinafter, the present invention will be specifically explained by showing examples. However, the present invention is not limited to the following examples. In the following description, "parts" and "%" representing amounts mean "parts by mass" and "% by mass", respectively, unless otherwise specified. Further, the operations described below were performed in an environment of normal temperature and normal pressure unless otherwise specified.

<Synthesis example 1: Synthesis of elastomer>
In a reaction vessel, 69 g of difunctional hydroxy group-terminated polybutadiene (Nippon Soda Co., Ltd. "G-3000", number average molecular weight = 3000, hydroxy group equivalent = 1800 g/eq.) and an aromatic hydrocarbon mixed solvent (Idemitsu Petroleum) were placed in a reaction vessel. 40 g of "Ipsol 150" (manufactured by Kagaku Co., Ltd.) and 0.005 g of dibutyltin laurate were mixed and uniformly dissolved. When the mixture became uniform, the temperature was raised to 60° C., and while stirring, 8 g of isophorone diisocyanate (“IPDI” manufactured by Evonik Degussa Japan, isocyanate group equivalent = 113 g/eq.) was added, and the reaction was carried out for about 3 hours.

Next, 23 g of cresol novolac resin (KA-1160 manufactured by DIC Corporation, hydroxyl equivalent = 117 g/eq.) and 60 g of ethyl diglycol acetate (manufactured by Daicel Corporation) were added to the reaction product, and the temperature was raised to 150° C. with stirring. The temperature was raised and the reaction was carried out for about 10 hours. The disappearance of the NCO peak at 2250 cm ^-1 was confirmed by FT-IR. Confirmation of disappearance of the NCO peak was regarded as the end point of the reaction, and the temperature of the reaction product was lowered to room temperature. Then, the reaction product was filtered through a 100 mesh filter cloth to obtain an elastomer having a butadiene structure and a phenolic hydroxyl group (phenolic hydroxyl group-containing butadiene resin: 50% by mass of non-volatile components). The number average molecular weight of the elastomer was 5900, and the glass transition temperature was -7°C.

<Production of resin sheet 1 with support>
10 parts of biphenyl-type epoxy resin ("NC-3000-L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: approx. 269 g/eq.), liquid 1,4-glycidylcyclohexane ("ZX1658", manufactured by Nippon Steel Chemical & Materials, epoxy equivalent) 135 g/eq.) 10 parts, bixylenol type epoxy resin (YX4000H manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 185 g/eq.), 10 parts of active ester compound (HPC-8000-65T manufactured by DIC Corporation, active 50 parts of triazine skeleton-containing phenolic curing agent ("LA-3018-50P" manufactured by DIC Corporation, hydroxyl equivalent: about 151 g/eq., solid content: 50 parts) % 2-methoxypropanol solution), 6 parts phenoxy resin (YX7553BH30 manufactured by Mitsubishi Chemical Corporation, 1:1 solution of MEK and cyclohexanone with a solid content of 30% by mass), 10 parts of a carbodiimide compound (V- 03'', active group equivalent: approximately 216 g/eq., solid content: 50% by mass toluene solution), 10 parts of spherical silica (average particle size 220 parts of phosphorus flame retardant (“HCA-HQ-HS”, manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-10-hydro-9- Oxa-10-phosphaphenanthrene-10-oxide) 1 part, rubber particles (Aica Kogyo Co., Ltd., Staphyloid AC3816N) 1 part, curing accelerator (4-dimethylaminopyridine (DMAP)), solid content 5% by mass 5 parts of MEK solution), 25 parts of methyl ethyl ketone, and 15 parts of cyclohexanone were mixed and uniformly dispersed using a high-speed rotating mixer to prepare resin varnish 1.

Next, resin varnish 1 was uniformly applied onto the release surface of a polyethylene terephthalate film with release treatment (“AL5” manufactured by Lintec Corporation, thickness 38 μm) as a support so that the thickness of the resin composition layer was 40 μm. It was coated and dried at 80 to 120°C (average 100°C) for 6 minutes to produce a resin sheet 1 with a support. In addition, by changing the coating thickness of the resin varnish 1, resin sheets 1 with supports in which the thicknesses of the resin composition layers after drying were 20 μm and 15 μm were also produced.

<Production of resin sheet 2 with support>
30 parts of biphenyl-type epoxy resin ("NC-3000-L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: approximately 269 g/eq.), bisphenol A-type epoxy resin ("828EL", manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 180 g/eq.). ) 20 parts, tetraphenylethane type epoxy resin (Mitsubishi Chemical's "jER1031S", epoxy equivalent: approx. 198 g/eq.), 5 parts, triazine skeleton-containing phenol novolac curing agent (DIC: "LA-7054", hydroxyl equivalent: approx. 125 g/eq., MEK solution with solid content of 60%) 10 parts, phenol novolak curing agent (DIC "TD2090", hydroxyl equivalent approximately 105 g/eq.) 6 parts, phenoxy resin (Mitsubishi Chemical "YX7553BH30") , 8 parts of a 1:1 solution of MEK and cyclohexanone with a solid content of 30% by mass), spherical silica (average particle size 0.5 μm, ad 140 parts of phosphorus flame retardant ("HCA-HQ-HS", manufactured by Sankosha, 10-(2,5-dihydroxyphenyl)-10-hydro-9-oxa-10-phos) 5 parts of faphenanthrene-10-oxide), 3 parts of a curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass), 25 parts of methyl ethyl ketone, and 15 parts of cyclohexanone were mixed, and the mixture was rotated at high speed. Resin varnish 2 was produced by uniformly dispersing it with a mixer.

In producing resin sheet 1 with a support, resin varnish 1 was replaced with resin varnish 2. A resin sheet 2 with a support was produced in the same manner as the resin sheet 1 with a support except for the above matters.

<Production of resin sheet 3 with support>
20 parts of bisphenol A type epoxy resin ("828EL" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 180 g/eq.), naphthol type epoxy resin ("ESN-475V" manufactured by Nippon Steel Chemical & Materials, epoxy equivalent: approximately 332 g/eq.). ), 10 parts of bixylenol type epoxy resin (“YX4000H” manufactured by Mitsubishi Chemical Corporation, epoxy equivalent: approximately 185 g/eq.), 10 parts of naphthylene ether type epoxy resin (“HP6000” manufactured by DIC Corporation, epoxy equivalent: approximately 260 g/eq.). ) 20 parts of cyanate ester curing agent (“BA230S75” manufactured by Lonza Japan Co., Ltd., cyanate equivalent: approximately 235 g/eq., MEK solution containing 75% by mass of non-volatile components), 10 parts of cyanate ester curing agent (“BADCy” manufactured by Lonza Japan Co., Ltd.) ”, cyanate equivalent: approx. 142 g/eq.) 10 parts, active ester compound (DIC “HPC-8000-65T”, active group equivalent: approx. 223 g/eq., toluene solution containing 65% by mass of non-volatile components), 20 parts of phenoxy Spherical silica surface-treated with 8 parts of resin (“YX7553BH30” manufactured by Mitsubishi Chemical Corporation, 1:1 solution of MEK and cyclohexanone with a solid content of 30% by mass) and an aminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) (Average particle size 0.5 μm, "SO-C2" manufactured by Admatex) 170 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with solid content 5% by mass) 3 parts, cobalt (III) Resin varnish 3 was prepared by mixing 5 parts of a 1% by mass MEK solution of acetylacetonate (manufactured by Tokyo Kasei Co., Ltd.), 40 parts of methyl ethyl ketone, and 20 parts of cyclohexanone and uniformly dispersing the mixture using a high-speed rotating mixer.

In producing resin sheet 1 with support, resin varnish 1 was replaced with resin varnish 3. A resin sheet 3 with a support was produced in the same manner as the resin sheet 1 with a support except for the above matters.

<Production of resin sheet 4 with support>
Phenolphthalimidine type epoxy resin (Nippon Kayaku Co., Ltd. "WHR-991S", epoxy equivalent: approx. 265 g/eq.) 5 parts, biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC-3000-L", epoxy equivalent) Approximately 269 g/eq.) 20 parts, 50 parts of the elastomer obtained in Synthesis Example 1, spherical silica surface-treated with a methacrylsilane coupling agent ("KBM503" manufactured by Shin-Etsu Chemical Co., Ltd.) (average particle size 0.08 μm, Specific surface area 30.7 m ² /g, Denka Co., Ltd. "UFP-30") 15 parts, phosphorus flame retardant (Sanko Co., Ltd. "HCA-HQ-HS", 10-(2,5-dihydroxyphenyl)-10- Hydro-9-oxa-10-phosphaphenanthrene-10-oxide) 5 parts, curing accelerator (1-benzyl-2-phenylimidazole (Shikoku Kasei Kogyo Co., Ltd. "1B2PZ") solid content 10% by mass) Resin varnish 4 was prepared by mixing 2 parts of methyl ethyl ketone solution and 20 parts of methyl ethyl ketone and uniformly dispersing the mixture using a high-speed rotating mixer.

In producing the resin sheet 1 with a support, resin varnish 1 was replaced with resin varnish 4. A resin sheet 4 with a support was produced in the same manner as the resin sheet 1 with a support except for the above matters.

<Production of resin sheet 5 with support>
In producing the resin sheet 1 with a support,
1) 220 parts of spherical silica (average particle size 0.5 μm, "SO-C2" manufactured by Admatex) surface-treated with an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) was subjected to aminosilane coupling. 270 parts of spherical alumina (average particle size 5.3 μm, "DAW-0525" manufactured by Denka Co., Ltd.) surface-treated with a chemical agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.),
2) Furthermore, 50 parts of spherical alumina (average particle size 0.3 μm, "ASFP-20" manufactured by Denka Co., Ltd.) whose surface was treated with an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
Except for the above matters, a support-attached resin sheet 5 was produced in the same manner as the support-attached resin sheet 1.

The components used in the preparation of resin varnishes 1 to 5 and their blending amounts (parts by mass of non-volatile components) are shown in the table below. Note that the content of component (a) represents the content when the nonvolatile components in the resin composition are 100% by mass.

<Evaluation of elastic modulus>
(1) Preparation of cured product for evaluation Glass cloth base epoxy resin double-sided copper-clad lamination is applied to the release agent-untreated surface of a PET film treated with a release agent (“501010” manufactured by Lintec Corporation, thickness 38 μm, 240 mm square). Plates ("R5715ES" manufactured by Panasonic Corporation, thickness 0.7 mm, 255 mm square) were stacked and fixed on four sides with polyimide adhesive tape (width 10 mm) (hereinafter sometimes referred to as "fixed PET film").

The produced resin sheets 1 to 5 with a support having a resin thickness of 40 μm were each laminated on the release-treated surface of the above-mentioned “fixed PET film” using a batch vacuum pressure laminator (manufactured by Meiki Co., Ltd., MVLP-500). did. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing for 30 seconds at 100° C. and a pressure of 0.74 MPa.

Next, the support was peeled off, and the resin sheet with the support was thermally cured under curing conditions of 90 minutes after being placed in an oven at 190°C.

After heat curing, the polyimide adhesive tape was peeled off, the cured product was removed from the glass cloth base epoxy resin double-sided copper-clad laminate, and the PET film ("501010" manufactured by Lintec Corporation) was also peeled off to obtain a sheet-like cured product. Ta. The obtained cured product is referred to as "cured product for evaluation."

(2) Evaluation of elastic modulus The obtained cured product for evaluation was subjected to a tensile test using a Tensilon universal testing machine (manufactured by A&D Co., Ltd.) in accordance with Japanese Industrial Standards (JIS K7127). The elastic modulus at °C was measured.

<Example 1>
(1) Lamination of the resin sheet with a support The prepared resin sheet 1 with a support having a resin thickness of 40 μm was coated with a micro-etching agent (MEC) using a batch vacuum pressure laminator (MVLP-500 manufactured by Meiki Co., Ltd.). The laminate was laminated so that the resin composition layer was in contact with both sides of a laminate whose copper surface had been roughened using a method such as "CZ8201" (manufactured by Kawasaki Co., Ltd.). Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing for 30 seconds at 100° C. and a pressure of 0.74 MPa.

(2) Curing of resin composition layer The resin composition layer of the laminated resin sheet with support was cured at 180° C. for 30 minutes to form an insulating layer.

(3) Formation of via hole (3-1) Formation of opening using laser A CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 50 μm, and the depth of the opening was 30 μm. Note that the depth of the opening was determined by calculating the difference between the unprocessed part of the insulating layer and the deepest part of the processed part by observing the cross section.

(3-2) Sandblasting process Next, using #2000 alumina abrasive slurry (average particle size 6.7 μm) as the abrasive grains, and using the support made by the CO ₂ laser as a mask, sandblast the openings. A via hole (top diameter: 50 μm) was formed. After sandblasting, the support was peeled off to obtain evaluation substrate 1.

<Example 2>
In Example 1, the resin sheet 1 with a support was changed to the resin sheet 2 with a support. Evaluation board 2 was obtained in the same manner as in Example 1 except for the above matters.

<Example 3>
In Example 1, the resin sheet 1 with a support was changed to the resin sheet 3 with a support. Evaluation board 3 was obtained in the same manner as in Example 1 except for the above matters.

<Example 4>
In Example 1, the resin sheet 1 with a support was changed to the resin sheet 4 with a support. Evaluation board 4 was obtained in the same manner as in Example 1 except for the above matters.

<Example 5>
In Example 1, the resin sheet 1 with a support was changed to the resin sheet 5 with a support. Evaluation board 5 was obtained in the same manner as in Example 1 except for the above matters.

<Example 6>
(1) Preparation of copper foil with resin composition layer Resin varnish is applied on copper foil with carrier (Mitsui Kinzoku Mining Co., Ltd., Microsyn MTEx, copper foil thickness 3 μm) so that the resin composition layer has a thickness of 40 μm. 1 was applied uniformly and dried at 80 to 120°C (average 100°C) for 6 minutes to produce a copper foil with a resin composition layer.

(2) Lamination of copper foil with a resin composition layer The obtained copper foil with a resin composition layer was applied to both sides of a laminate whose copper surface had been roughened using a micro-etching agent (“CZ8201” manufactured by MEC Corporation). The resin composition layer was laminated using a vacuum pressure laminator (manufactured by Meiki Co., Ltd., MVLP-500) so that the resin composition layer was in contact with the laminate. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing for 30 seconds at 100° C. and a pressure of 0.74 MPa.

(3) Curing of resin composition layer The resin composition layer laminated with carrier-coated copper foil was cured at 180° C. for 30 minutes to form an insulating layer.

(4) Formation of via hole (4-1) Formation of opening using laser After peeling off the carrier, an opening was formed using a CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics). The top diameter (diameter) of the opening on the surface of the insulating layer was 50 μm, and the depth of the opening was 30 μm.

(4-2) Sandblasting process Next, using #2000 alumina abrasive slurry (average particle size 6.7μm) as the abrasive grains, and using a copper foil with an aperture made by a CO ₂ laser as a mask, sandblast the opening. A via hole (top diameter (diameter) of 50 μm) was formed. After sandblasting, the copper foil was peeled off to obtain an evaluation board 6.

<Example 7>
(1) Lamination of the resin sheet with a support The produced resin sheet 1 with a support having a resin thickness of 40 μm was laminated using a batch vacuum pressure laminator (manufactured by Meiki Co., Ltd., MVLP-500) with a copper foil with a carrier (Mitsui The resin composition layer was laminated onto Microsyn MTEx manufactured by Kinzoku Mining Co., Ltd. (copper foil thickness: 3 μm) so that it was in contact with the resin composition layer. The laminate was depressurized for 30 seconds to bring the atmospheric pressure to 13 hPa or less, and then pressed for 30 seconds at 100° C. and a pressure of 0.74 MPa to obtain a copper foil with a resin composition layer.

(2) Lamination of copper foil with a resin composition layer The obtained copper foil with a resin composition layer was applied to both sides of a laminate whose copper surface had been roughened using a micro-etching agent (“CZ8201” manufactured by MEC Corporation). The resin composition layer was laminated using a vacuum pressure laminator (manufactured by Meiki Co., Ltd., MVLP-500) so that the resin composition layer was in contact with the laminate. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing for 30 seconds at 100° C. and a pressure of 0.74 MPa.

(3) Curing of resin composition layer The resin composition layer was cured at 180° C. for 30 minutes to form an insulating layer.

(4) Formation of opening in copper foil An opening for forming a trench was formed in a part of the carrier-attached copper foil by etching with the above-mentioned micro-etching agent.

(5) Formation of via hole (5-1) Formation of opening using laser A CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 50 μm, and the depth of the opening was 30 μm.

(5-2) Sandblasting process Next, using #2000 alumina abrasive slurry (average particle size 6.7μm) as the abrasive grains, and using a copper foil with an aperture made by a CO ₂ laser as a mask, sandblast the opening. A via hole (top diameter (diameter) of 50 μm) was formed. Further, by sandblasting, the insulating layer was also dug in the portion where the hole for forming the trench was formed, and a trench was formed. After sandblasting, the copper foil was peeled off to obtain an evaluation board 7.

<Example 8>
In Example 7, (3) the following operations were performed after curing the resin composition layer, and (4) no openings in the copper foil were formed. Evaluation board 8 was obtained in the same manner as in Example 7 except for the above matters.

(4) Lamination of dry film A dry film (manufactured by Nikko Materials, NCM325, thickness 25 μm) was laminated on the surface of the copper foil. The dry film was laminated using a batch vacuum pressure laminator ("MVLP-500" manufactured by Meiki Manufacturing Co., Ltd.). After reducing the pressure to 13 hPa or less by reducing the pressure for 30 seconds, the dry film was laminated at a pressure of 0.1 MPa and a temperature of 70°C. Then, pressure was applied for 20 seconds. Thereafter, a glass mask having a trench pattern was placed on the polyethylene terephthalate film serving as a protective layer of the dry film, and UV irradiation was performed using a UV lamp at an irradiation intensity of 20 mJ/cm ² . After UV irradiation, spray treatment was performed for 50 seconds at a spray pressure of 0.15 MPa using a 1% aqueous sodium carbonate solution at 25°C. Thereafter, water washing was performed to form an opening for forming a trench pattern.

<Example 9>
(1) Preparation of copper foil with resin composition layer Resin varnish 1 was uniformly applied onto copper foil (manufactured by JX Nippon Mining & Metals Co., Ltd., JDLC, thickness 12 μm) so that the thickness of the resin composition layer was 40 μm. It was dried at ~120°C (average 100°C) for 6 minutes to produce a copper foil with a resin composition layer.
(2) Lamination of copper foil with copper foil and resin composition layer The copper surface of the obtained copper foil with resin composition layer was roughened using a micro-etching agent (“CZ8201” manufactured by MEC Corporation). Both sides of the laminate were laminated using a vacuum pressure laminator (manufactured by Meiki Co., Ltd., MVLP-500) so that the resin composition layer was in contact with the laminate. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa or less, and then pressing for 30 seconds at 100° C. and a pressure of 0.74 MPa.

(3) Curing of the resin composition layer The resin composition layer is cured under the curing conditions of 180° C. for 30 minutes on the laminated board with the copper foil laminated with the resin composition layer to form an insulating layer, and then the copper foil and the cured layer are cured. A laminated board with attached was obtained.

(4) Half etching of copper foil Half etching was performed to reduce the copper thickness from 12 μm to 5 μm by immersing the copper foil and the laminate with the hardened layer in iron chloride solution, and the adhering iron chloride solution was washed away with pure water. .

(5) Pretreatment for laser processing Next, pretreatment for laser processing was performed using a pretreatment liquid for laser processing ("MULTIBOND 100", manufactured by MacDiarmid Performance Solutions Japan).

(6) Formation of via hole (6-1) Formation of opening using laser A CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 50 μm, and the depth of the opening was 30 μm.

(6-2) Sandblasting process Next, using #2000 alumina abrasive slurry (average particle size 6.7 μm) as the abrasive grains, and using a copper foil with an aperture made by a CO ₂ laser as a mask, sandblast the opening. A via hole (top diameter (diameter) of 50 μm) was formed. After sandblasting, the copper foil was peeled off to obtain a substrate 9 for evaluation.

<Example 10>
In Example 9, (4) half-etching of the copper foil was not performed. An evaluation substrate 10 was obtained in the same manner as in Example 9 except for the above matters.

<Example 11>
In Example 1, the resin sheet 1 with a support having a resin thickness of 40 μm was changed to the resin sheet 1 with a support having a resin thickness of 20 μm,
Via holes were formed as follows. An evaluation substrate 11 was obtained in the same manner as in Example 1 except for the above matters.

(1) Formation of via hole (1-1) Formation of opening using laser A CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 30 μm, and the depth of the opening was 15 μm.

(1-2) Sandblasting process Next, using #3000 alumina abrasive slurry (average particle size 4.0 μm) as the abrasive grains, and using the support made with the CO ₂ laser as a mask, sandblast the openings. A via hole (top diameter (diameter) of 30 μm) was formed. After sandblasting, the support was peeled off to obtain a substrate 11 for evaluation.

<Example 12>
In Example 7, the resin sheet 1 with a support having a resin thickness of 40 μm was changed to the resin sheet 1 with a support having a resin thickness of 15 μm,
Via holes were formed as follows. An evaluation substrate 12 was obtained in the same manner as in Example 7 except for the above matters.

(1) Formation of via hole (1-1) Formation of opening using laser A UV-YAG laser processing machine (“LU-2L212/M50L” manufactured by Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 20 μm, and the depth of the opening was 12 μm.

(1-2) Sandblasting process Next, using #3000 alumina abrasive slurry (average particle size 4.0 μm) as the abrasive grains, and using the copper foil that had been opened by UV-YAG laser as a mask, sandblast the openings. Processing was performed to form a via hole (top diameter: 20 μm). After sandblasting, the copper foil was peeled off to obtain an evaluation board 12.

<Example 13>
In Example 12, the carrier-attached copper foil (manufactured by Mitsui Kinzoku Mining Co., Ltd., Microthin MTEx, copper foil thickness 3 μm) was replaced with a dry film (manufactured by Asahi Kasei Co., Ltd., trade name “ATP-10VTDS”, thickness 10 μm). An evaluation substrate 13 was obtained in the same manner as in Example 12 except for the above.

<Example 14>
In Example 13, an opening for a trench pattern was formed in the dry film using a mask before forming the opening with a UV-YAG laser. An evaluation substrate 14 was obtained in the same manner as in Example 13 except for the above matters.

<Example 15>
In Example 2, the resin sheet 2 with a support having a resin thickness of 40 μm was changed to the resin sheet 2 with a support having a resin thickness of 25 μm,
Via holes were formed as follows. An evaluation substrate 15 was obtained in the same manner as in Example 2 except for the above matters.

(1) Formation of via hole (1-1) Formation of opening using laser A CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 30 μm, and the depth of the opening was 25 μm.

(1-2) Via processing by sandblasting Next, using #3000 alumina abrasive slurry (average particle size 4.0 μm) as the abrasive grains, and using the support with the CO ₂ laser aperture as a mask, the apertures were Sandblasting was performed to form a via hole (top diameter: 30 μm). After sandblasting, the support was peeled off to obtain an evaluation substrate 15.

<Comparative example 1>
In Example 1, via holes were formed as follows. An evaluation board 16 was obtained in the same manner as in Example 1 except for the above matters.

(1) Formation of via hole After forming the insulating layer, the PET film serving as the support was peeled off. A via hole was formed in the insulating layer from which the support was peeled off using a UV-YAG laser processing machine ("LU-2L212/M50L" manufactured by Via Mechanics) to obtain a substrate 16 for evaluation. Note that the top diameter (diameter) of the via hole on the surface of the insulating layer was 50 μm.

<Comparative example 2>
In Example 1, via holes were formed as follows. An evaluation board 17 was obtained in the same manner as in Example 1 except for the above matters.

(1) Formation of via hole A via hole was formed using a CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics, Inc.) to obtain a substrate 17 for evaluation. Note that the top diameter (diameter) of the via hole on the surface of the insulating layer was 50 μm.

<Comparative example 3>
In Example 1, via holes were formed as follows. An evaluation board 18 was obtained in the same manner as in Example 1 except for the above matters.

(1) Formation of via hole (1-1) Formation of opening using laser A CO ₂ laser processing machine (“LC-2E21B/1C” manufactured by Hitachi Via Mechanics) was used to form an opening. The top diameter (diameter) of the opening on the surface of the insulating layer was 50 μm, and the depth of the opening was 35 μm. This is called a substrate.

(1-2) Desmear treatment The substrate was immersed in a swelling liquid, Swelling Dip Seculigand P manufactured by Atotech Japan Co., Ltd., containing diethylene glycol monobutyl ether at 60°C for 5 minutes, and then a roughening liquid, manufactured by Atotech Japan Co., Ltd. The solution was immersed in Concentrate Compact P (aqueous solution of KMnO ₄ : 60 g/L, NaOH: 40 g/L) at 80°C for 30 minutes, and finally, as a neutralizing solution, Reduction Shoryushin Securi, manufactured by Atotech Japan Co., Ltd. By immersing it in Gantt P at 40° C. for 5 minutes, the bottom of the opening was scraped to form a via hole.

<Comparative example 4>
In Example 1, via holes were formed as follows. An evaluation substrate 19 was obtained in the same manner as in Example 1 except for the above matters.

(1) Formation of via hole (1-1) Formation of via pattern using sandblasting resist A via with a diameter of 50 μm is formed on the surface of the insulating layer using a sandblasting resist (manufactured by Nikko Materials, NCM250, thickness 50 μm). Patterning was performed as follows.

(1-2) Sandblasting process Next, using #2000 alumina abrasive slurry (average particle size 6.7μm) as the abrasive grains, and using the sandblasting resist on which the via pattern was formed as a mask, sandblast the via area. As a result, an evaluation board 19 was obtained.

<Comparative example 5>
In Comparative Example 4, (1) formation of via holes was performed as follows. An evaluation substrate 20 was obtained in the same manner as in Comparative Example 4 except for the above matters.

(1) Formation of via hole (1-1) Formation of via pattern using sandblasting resist A via with a diameter of 150 μm is formed on the surface of the insulating layer using a sandblasting resist (manufactured by Nikko Materials, NCM250, thickness 50 μm). Patterning was performed as follows.

(1-2) Via processing by sandblasting Next, using #1200 alumina abrasive slurry (average grain size 9.5 μm) as the abrasive grains, and using the sandblasting resist on which the via pattern was formed as a mask, sandblast the via area. Processing was performed to obtain an evaluation substrate 20.

<Evaluation of via diameter>
○: Via holes can be formed with an opening diameter of 100 μm or less.
×: A via hole cannot be formed with an opening diameter of 100 μm or less.

<Evaluation of smear removal performance>
The evaluation substrates 1 to 20 obtained in Examples and Comparative Examples were immersed in a swelling liquid, Swelling Dip Securigand P manufactured by Atotech Japan Co., Ltd., containing diethylene glycol monobutyl ether at 60°C for 5 minutes, and then roughened. It was immersed in Concentrate Compact P (KMnO ₄ : 60 g/L, NaOH: 40 g/L aqueous solution) manufactured by Atotech Japan Co., Ltd. at 80°C for 15 minutes as a neutralizing liquid, and finally, as a neutralizing liquid, it was immersed in Concentrate Compact P manufactured by Atotech Japan Co., Ltd. It was immersed in Reduction Shoryushin Securigant P at 40°C for 5 minutes. Thereafter, the via holes were observed using an electron microscope and evaluated based on the following criteria.
○: No resin residual is observed at the bottom of the via hole.
×: Resin residue is observed at the bottom of the via hole.

<Helloing evaluation>
After evaluating the smear removability, the evaluation substrate was subjected to cross-sectional observation using a FIB-SEM composite device ("SMI3050SE" manufactured by SII Nano Technology). Specifically, an FIB (focused ion beam) was used to cut the insulating layer so that a cross section parallel to the thickness direction of the insulating layer and passing through the center of the via bottom of the via hole appeared. This cross section was observed by SEM. In some of the images observed, a gap formed by the insulating layer being peeled off from the copper foil of the inner layer substrate was seen continuously from the edge of the via bottom. Therefore, the distance from the edge of the via bottom to the outer edge of the gap was measured as the harrowing distance, and evaluated based on the following criteria.
○: Haloing distance is 5 μm or less.
×: Haloing distance exceeds 5 μm.

<Evaluation of via processability>
(1) Evaluation of via machinability using CO ₂ laser The evaluation was based on the number of shots required to make the opening depth a predetermined depth by CO ₂ laser processing, and the evaluation was made based on the following criteria.
◎: Number of shots is 1.
○: Number of shots is 2.
×: Number of shots is 3 or more.

(2) Evaluation of via machinability by UV-YAG laser The evaluation was based on the number of shots required to make the opening depth a predetermined depth by UV-YAG laser machining, and the evaluation was made based on the following criteria.
○: Number of shots is 20 or less.
×: The number of shots exceeds 20.

(3) Evaluation of via processability by sandblasting The insulating layer at the bottom of the opening was removed and the sandblasting time required until the conductor layer of the laminate was exposed was evaluated, and the evaluation was based on the following criteria.
◎: Processing time is less than 5 minutes.
○: Processing time is 5 minutes or more and less than 10 minutes.
×: Processing time is 10 minutes or more.

＊表中、「ＷＢ」はウェットブラスト処理を意味する。無機充填材の含有量は、樹脂組成物中の不揮発成分を１００質量％としたときの値である。

*In the table, "WB" means wet blasting. The content of the inorganic filler is a value when the nonvolatile components in the resin composition are 100% by mass.

10 Inner layer circuit board 11 Support substrate 12 Metal layer 10a Main surface 21 Support 22 Insulating layer 30 Opening 40 Via hole 50 Trench 60 Metal foil 61 Hole 70 Dry film 71 Hole 80 Filled via 22U Surface of insulating layer opposite to metal layer 220 Via bottom 220C Center of via bottom 240 Discolored portion 250 Edge of via bottom of via hole 260 Gap portion 270 Outer peripheral end of gap a Opening depth b Opening diameter (via hole diameter)
c Total value of mask thickness and opening depth Wb Haloing distance from the edge of via bottom

Claims (13)

(A) forming an opening in the insulating layer containing the cured resin composition using a laser; and (B) sandblasting the opening using abrasive grains to form a via hole in this order. (A) The depth of the opening formed in step (A) is 50% or more and 95% or less of the thickness of the insulating layer . The method for manufacturing a printed wiring board according to claim 1, wherein the abrasive grains have an average particle diameter of 10 μm or less. The method for manufacturing a printed wiring board according to claim 1 or 2, wherein the depth of the opening formed in the step (A) is 50% or more and 85% or less of the thickness of the insulating layer. Step (B) is a step of forming a via hole by colliding abrasive grains with the bottom surface of the opening through a mask,
The printed wiring according to any one of claims 1 to 3, wherein the ratio of the total value of the thickness of the mask and the depth of the opening to the opening diameter of the via hole (total value/opening diameter) is 3 or less. Method of manufacturing the board. Step (B) is a step of forming a via hole by colliding abrasive grains with the bottom surface of the opening through a mask,
According to any one of claims 1 to 3, the ratio of the total value of the thickness of the mask and the depth of the opening to the opening diameter of the via hole (total value/opening diameter) is 0.5 or more and less than 2. A method of manufacturing the printed wiring board described. The method for manufacturing a printed wiring board according to any one of claims 1 to 5 , wherein the insulating layer has an elastic modulus of 0.1 GPa or more at 23°C. The method for manufacturing a printed wiring board according to any one of claims 1 to 6 , wherein the resin composition contains an inorganic filler. 8. The method for producing a printed wiring board according to claim 7 , wherein the content of the inorganic filler is 20% by mass or more when the nonvolatile component in the resin composition is 100% by mass. The method for manufacturing a printed wiring board according to any one of claims 1 to 8 , wherein the resin composition contains a curable resin. The method for manufacturing a printed wiring board according to claim 9 , wherein the content of the curable resin is 10% by mass or more when the nonvolatile component in the resin composition is 100% by mass. The method for manufacturing a printed wiring board according to claim 9 or 10 , wherein the curable resin contains an epoxy resin and a curing agent. The method for manufacturing a printed wiring board according to claim 11 , wherein the curing agent is one or more selected from phenolic resins, active ester resins, and cyanate ester resins. The method for manufacturing a printed wiring board according to any one of claims 1 to 12 , wherein the laser is a CO ₂ laser or a UV-YAG laser.

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