JP7331812B2 - Wiring board and semiconductor device - Google Patents

Description

The present invention relates to a wiring board manufacturing method. Furthermore, it relates to a wiring board and a semiconductor device.

As a method for manufacturing wiring boards (printed wiring boards), a build-up method is widely used in which conductive layers and insulating layers having circuits formed thereon are alternately stacked, and the insulating layers are formed by curing a resin composition. is known (see Patent Document 1, for example).

JP 2015-82535 A

2. Description of the Related Art In recent years, electronic devices are becoming lighter, thinner, shorter and smaller. Along with this, there is a demand for a flexible wiring board that can be folded and stored in an electronic device. Further, in order to make the wiring board thinner, there is a demand for a wiring board having an embedded wiring layer.

SUMMARY OF THE INVENTION An object of the present invention is to provide a novel method for manufacturing a flexible wiring board having an embedded wiring layer.

That is, the present invention includes the following contents.
[1] (1) A step of preparing a substrate with a wiring layer having a substrate and a wiring layer provided on at least one surface of the substrate;
(2) An adhesive sheet containing (i) a thermosetting resin composition layer and (ii) a resin film layer is placed on a substrate with a wiring layer so that the wiring layer is embedded in the (i) thermosetting resin composition layer. lamination on the material and thermosetting to form an insulating layer;
(3) forming a via hole in the insulating layer;
(4) forming a conductor layer; and (5) removing the substrate;
A method of manufacturing a wiring board, comprising:
[2] The adhesive sheet further includes (iii) a metal foil or a thermosetting resin composition layer, (i) a thermosetting resin composition layer, (ii) a resin film layer, and (iii) a metal foil or The method according to [1], including in order with the thermosetting resin composition layer.
[3] The method according to [1] or [2], wherein the via hole is formed by laser irradiation.
[4] The method according to any one of [1] to [3], including the step of roughening before the step of forming the conductor layer.
[5] The method according to any one of [1] to [4], wherein the wiring board is a flexible wiring board.
[6] The method according to any one of [1] to [5], wherein the adhesive sheet after thermosetting has an elongation at break of 2% or more.
[7] (ii) The method according to any one of [1] to [6], wherein the surface of the resin film layer is corona-treated, plasma-treated, or UV-treated.
[8] The method according to any one of [1] to [7], wherein the metal foil is copper foil.
[9] The method according to any one of [1] to [8], wherein the wiring pattern has a minimum pitch of 40 μm or less.
[10] A wiring board comprising a resin film layer, an insulating layer, and an embedded wiring layer embedded in the insulating layer.
[11] The wiring board according to [10], which is a flexible wiring board.
[12] The wiring board according to [10] or [11], wherein the insulating layer has a thickness of 2 μm or more.
[13] The wiring board according to any one of [10] to [12], wherein the resin film layer has a thickness of 2 μm or more.
[14] A semiconductor device comprising the wiring board according to any one of [10] to [13].

ADVANTAGE OF THE INVENTION According to this invention, the novel manufacturing method of the flexible wiring board provided with the embedded wiring layer can be provided.

Further, according to the manufacturing method of the present invention, it is possible to provide a method for manufacturing a wiring board which is excellent in bendability and reflow warpage behavior.

FIG. 1 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 2 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 3 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 4 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 5 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 6 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 7 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 8 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 9 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 10 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 11 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 12 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 13 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 14 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 15 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 16 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 17 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 18 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 19 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 20 is a schematic cross-sectional view for explaining the manufacturing process of the wiring board. FIG. 21 is a schematic cross-sectional view for explaining a wiring board. FIG. 22 is a schematic cross-sectional view for explaining the wiring board. FIG. 23 is a schematic cross-sectional view for explaining a wiring board.

Before describing the manufacturing method of the wiring board of the present invention, the adhesive sheet used in the manufacturing method will be described.

[Adhesive sheet]
The adhesive sheet includes (i) a thermosetting resin composition layer and (ii) a resin film layer. The adhesive sheet preferably further includes (iii) a metal foil or a thermosetting resin composition layer. In a preferred embodiment of the adhesive sheet, (i) a thermosetting resin composition layer and (ii) a resin film layer are bonded together, and (ii) the resin film layer and (iii) a metal foil or thermosetting The resin composition layer is joined. Each layer constituting the adhesive sheet will be described in detail below.

<(i) Thermosetting resin composition layer>
The adhesive sheet includes (i) a thermosetting resin composition layer. Although the details will be described later, when manufacturing a wiring board, the wiring layer is embedded in (i) the thermosetting resin composition layer, thereby forming an embedded wiring layer. (i) The thermosetting resin composition constituting the thermosetting resin composition layer is not particularly limited as long as the cured product thereof has sufficient insulating properties. Examples of such resin compositions include compositions containing a thermosetting resin and its curing agent. As the thermosetting resin, conventionally known thermosetting resins used for forming insulating layers of wiring boards can be used, and among them, epoxy resins are preferable. Accordingly, in one embodiment, the thermoset resin composition comprises (a) an epoxy resin and (b) a curing agent. If necessary, the thermosetting resin composition may further contain (c) an inorganic filler, (d) a thermoplastic resin, (e) a curing accelerator, (f) a flame retardant, and (g) an organic filler. It may contain a drug.

-(a) epoxy resin-
Examples of epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol novolac type epoxy resin, Phenol novolak type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolak type epoxy resin, biphenyl type epoxy resin Epoxy resins, linear aliphatic epoxy resins, epoxy resins having a butadiene structure, alicyclic epoxy resins, heterocyclic epoxy resins, spiro ring-containing epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins, Methylol-type epoxy resins, tetraphenylethane-type epoxy resins, and the like are included. An epoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type. Component (a) is preferably one or more selected from bisphenol A type epoxy resins, bisphenol F type epoxy resins, and biphenyl type epoxy resins.

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

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, phenol novolak type epoxy resin, and alicyclic epoxy resin having an ester skeleton. , and butadiene structures are preferred, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin and naphthalene type epoxy resin are more preferred. Specific examples of liquid epoxy resins include "HP4032", "HP4032D" and "HP4032SS" (naphthalene type epoxy resins) manufactured by DIC Corporation, "828US" and "jER828EL" manufactured by Mitsubishi Chemical Corporation (bisphenol A type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), "YL7760" (bisphenol AF type epoxy resin), Nippon Steel & Sumikin Chemical Co., Ltd. "ZX1059" ( A mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin), "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation, "Celoxide 2021P" manufactured by Daicel Corporation (ester skeleton alicyclic epoxy resin), “PB-3600” (epoxy resin having a butadiene structure), “ZX1658” and “ZX1658GS” manufactured by Nippon Steel Chemical Co., Ltd. (liquid 1,4-glycidylcyclohexane). be done. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Solid epoxy resins include naphthalene type tetrafunctional epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, naphthol type epoxy resin, biphenyl type epoxy resin, naphthylene ether type epoxy resin, Anthracene type epoxy resin, bisphenol A type epoxy resin and tetraphenylethane type epoxy resin are preferred, and naphthalene type tetrafunctional epoxy resin, naphthol type epoxy resin and biphenyl type epoxy resin 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 Corporation. ” (cresol novolac type epoxy resin), “N-695” (cresol novolac type epoxy resin), “HP-7200” (dicyclopentadiene type epoxy resin), “HP-7200HH”, “HP-7200H”, “EXA7311 ”, “EXA7311-G3”, “EXA7311-G4”, “EXA7311-G4S”, “HP6000” (naphthylene ether type epoxy resin), Nippon Kayaku Co., Ltd. “EPPN-502H” (trisphenol type epoxy resin), "NC7000L" (naphthol novolac type epoxy resin), "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin), "ESN475V" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd. (naphthol type epoxy resin), "ESN485" (naphthol novolac type epoxy resin), "YX4000H" manufactured by Mitsubishi Chemical Corporation, "YL6121" (biphenyl type epoxy resin), "YX4000HK" (bixylenol type epoxy resin), "YX8800" (anthracene type epoxy resin), Osaka Gas Chemicals Co., Ltd. "PG-100", "CG-500", Mitsubishi Chemical Co., Ltd. "YL7800" (fluorene type epoxy resin), Mitsubishi Chemical Co., Ltd. "jER1010" (solid bisphenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin) and the like.

The liquid epoxy resin is preferably an aromatic epoxy resin that has two or more epoxy groups in one molecule and is liquid at a temperature of 20°C, and the solid epoxy resin has three or more epoxy groups in one molecule. and is solid at a temperature of 20° C. is preferred. The aromatic epoxy resin referred to in the present invention means an epoxy resin having an aromatic ring structure in its molecule.

When a liquid epoxy resin and a solid epoxy resin are used together as epoxy resins, the ratio by mass (liquid epoxy resin: solid epoxy resin) is in the range of 1:0.1 to 1:5. preferable. By setting the amount ratio of the liquid epoxy resin to the solid epoxy resin in such a range, i) when used in the form of an adhesive sheet, moderate adhesiveness is provided, and ii) when used in the form of an adhesive sheet. iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the above effects i) to iii), the ratio of the liquid epoxy resin to the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is in the range of 1:0.3 to 1:4 in mass ratio. is more preferred, and a range of 1:0.6 to 1:3 is even more preferred.

The content of the epoxy resin in the resin composition is preferably 5% by mass or more, more preferably 9% by mass or more, and still more preferably 13% by mass, from the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulation reliability. That's it. The upper limit of the content of the epoxy resin is not particularly limited as long as the effect of the present invention is exhibited, but it is preferably 50% by mass or less, more preferably 40% by mass or less.

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

The epoxy equivalent of the epoxy resin is preferably 50-5000, more preferably 50-3000, even more preferably 80-2000, still more preferably 110-1000. Within this range, the crosslink density of the cured product is sufficient, and an insulating layer with a small surface roughness can be obtained. The epoxy equivalent can be measured according to JIS K7236, and is the mass of a resin containing one equivalent of epoxy groups.

The weight average molecular weight of the epoxy resin is preferably 100-5000, more preferably 250-3000, still more preferably 400-1500. Here, the weight average molecular weight of the epoxy resin is the polystyrene equivalent weight average molecular weight measured by gel permeation chromatography (GPC).

-(b) curing agent-
The curing agent is not particularly limited as long as it has the function of curing the epoxy resin. Examples include carbodiimide curing agents. A single curing agent may be used alone, or two or more curing agents may be used in combination. Component (b) is preferably one or more selected from phenol-based curing agents, naphthol-based curing agents, active ester-based curing agents, and cyanate ester-based curing agents.

As the phenolic curing agent and the naphtholic curing agent, a phenolic curing agent having a novolac structure or a naphtholic curing agent having a novolac structure is preferable from the viewpoint of heat resistance and water resistance. From the viewpoint of adhesion to the wiring layer, a nitrogen-containing phenolic curing agent is preferable, and a triazine skeleton-containing phenolic curing agent is more preferable. Among them, a triazine skeleton-containing phenol novolac curing agent is preferable from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion to the wiring layer.

Specific examples of phenol-based curing agents and naphthol-based curing agents include, for example, “MEH-7700”, “MEH-7810” and “MEH-7851” manufactured by Meiwa Kasei Co., Ltd., manufactured by Nippon Kayaku Co., Ltd. "NHN", "CBN", "GPH", Nippon Steel & Sumikin Co., Ltd. "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN375", "SN395" , "LA7052", "LA7054", "LA3018" and "EXB-9500" manufactured by DIC Corporation.

An active ester curing agent is also preferable from the viewpoint of obtaining an insulating layer having excellent adhesion to the wiring layer. The active ester-based curing agent is not particularly limited, but generally contains an ester group with high reaction activity such as phenol esters, thiophenol esters, N-hydroxyamine esters, esters of heterocyclic hydroxy compounds in one molecule. A compound having two or more is preferably used. The active ester curing agent is preferably 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, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferred, and an active ester curing agent obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound is more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenol 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, phloroglucine, Benzenetriol, dicyclopentadiene-type diphenol compound, phenol novolak, and the like. Here, the term "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing one molecule of dicyclopentadiene with two molecules of phenol.

Specifically, an active ester compound containing a dicyclopentadiene type diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester compound containing a benzoylated product of phenol novolak are preferred. Among them, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene-type diphenol structure are more preferable. "Dicyclopentadiene-type diphenol structure" represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

Commercially available active ester curing agents include "EXB9451", "EXB9460", "EXB9460S", and "HPC-8000-65T" (manufactured by DIC Corporation) as active ester compounds containing a dicyclopentadiene type diphenol structure. ), "EXB9416-70BK" (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated phenol novolak, benzoyl of phenol novolac "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing a compound, "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester curing agent that is an acetylated product of phenol novolac, and a benzoylated product of phenol novolak. Examples of active ester curing agents include "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), and "YLH1048" (manufactured by Mitsubishi Chemical Corporation).

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

Examples of cyanate ester curing agents include bisphenol A dicyanate, polyphenolcyanate, oligo(3-methylene-1,5-phenylenecyanate), 4,4′-methylenebis(2,6-dimethylphenylcyanate), 4,4 '-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatophenylmethane), bis(4-cyanate-3,5-dimethyl Bifunctional cyanate resins such as phenyl)methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether, phenol Polyfunctional cyanate resins derived from novolacs, cresol novolaks, etc., and prepolymers obtained by partially triazine-forming these cyanate resins. Specific examples of cyanate ester curing agents include "PT30" and "PT60" (both phenol novolak type polyfunctional cyanate ester resins), "BA230" and "BA230S75" (bisphenol A dicyanate) manufactured by Lonza Japan Co., Ltd. a prepolymer that is partially or wholly triazined to form a trimer), and the like.

Specific examples of carbodiimide-based curing agents include “V-03” and “V-07” manufactured by Nisshinbo Chemical Co., Ltd., and the like.

The ratio of the epoxy resin to the curing agent is [total number of epoxy groups in the epoxy resin]:[total number of reactive groups in the curing agent], and is preferably in the range of 1:0.01 to 1:2. 1:0.015 to 1:1.5 is more preferred, and 1:0.02 to 1:1 is even more preferred. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group, or the like, and varies depending on the type of curing agent. In addition, the total number of epoxy groups in the epoxy resin is the sum of the values obtained by dividing the solid content mass of each epoxy resin by the epoxy equivalent for all epoxy resins, and the total number of reactive groups in the curing agent is It is a value obtained by dividing the solid content mass of each curing agent by the reactive group equivalent and totaling all the curing agents. By setting the ratio between the epoxy resin and the curing agent within this range, the heat resistance of the cured product of the resin composition is further improved.

In one embodiment, the thermoset resin composition comprises (a) an epoxy resin and (b) a curing agent as described above. The thermosetting resin composition includes (a) a mixture of a liquid epoxy resin and a solid epoxy resin as the epoxy resin (the mass ratio of liquid epoxy resin:solid epoxy resin is preferably 1:0.1 to 1:5, 1:0.3 to 1:4, more preferably 1:0.6 to 1:3), and (b) a phenolic curing agent, a naphthol curing agent, an active ester curing agent and It is preferable to contain one or more selected from the group consisting of cyanate ester curing agents (preferably one or more selected from the group consisting of active ester curing agents and cyanate ester curing agents).

The content of the curing agent in the thermosetting resin composition is not particularly limited, but is preferably 30% by mass or less, more preferably 25% by mass or less, and still more preferably 20% by mass or less. Moreover, the lower limit is not particularly limited, but 2% by mass or more is preferable.

-(c) Inorganic filler-
The material of the inorganic filler is not particularly limited, but examples include silica, alumina, 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, silica is particularly suitable. As silica, spherical silica is preferable. An inorganic filler may be used individually by 1 type, and may be used in combination of 2 or more type.

The average particle size of the inorganic filler is preferably 2 μm or less, more preferably 1 μm or less, still more preferably 0.8 μm or less, and more preferably 0.6 μm or less, from the viewpoint of good embedding properties. Although the lower limit of the average particle size is not particularly limited, it is preferably 0.01 μm or more, more preferably 0.05 μm or more, and still more preferably 0.1 μm or more. Examples of commercially available inorganic fillers having such an average particle size include “YC100C”, “YA050C”, “YA050C-MJE” and “YA010C” manufactured by Admatechs Co., Ltd., manufactured by Denki Kagaku Kogyo Co., Ltd. "UFP-30", "Silfil NSS-3N", "Silfil NSS-4N", "Silfil NSS-5N" manufactured by Tokuyama Co., Ltd., "SOC2" and "SOC1" manufactured by Admatechs Co., Ltd., and the like.

The average particle size of the inorganic filler can be measured by a laser diffraction/scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler is prepared on a volume basis using a laser diffraction/scattering particle size distribution analyzer, and the median diameter thereof can be used as the average particle size for measurement. As the measurement sample, one obtained by ultrasonically dispersing an inorganic filler in water can be preferably used. As a laser diffraction scattering type particle size distribution analyzer, "LA-500" manufactured by HORIBA, Ltd. can be used.

Inorganic fillers include aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, organosilazane compounds, and titanate coupling agents from the viewpoint of improving moisture resistance and dispersibility. It is preferably treated with one or more surface treatment agents such as. Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. silane), Shin-Etsu Chemical Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "SZ-31" (hexamethyldisilazane), Shin-Etsu Chemical Co., Ltd. "KBM103" (phenyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM-4803" (long chain epoxy type silane coupling agents) and the like.

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 more preferably 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 preventing an increase in the melt viscosity of the resin varnish and the melt viscosity in the sheet form, it is preferably 1 mg/m ² or less, more preferably 0.8 mg/m ² or less, and further 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 (eg, methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with the surface treatment agent, and ultrasonic cleaning is performed at 25° C. for 5 minutes. After removing the supernatant liquid and drying the solid content, a carbon analyzer can be used to measure the amount of carbon per unit surface area of the inorganic filler. As a carbon analyzer, "EMIA-320V" manufactured by Horiba Ltd. can be used.

The content of the inorganic filler in the thermosetting resin composition is preferably 20% by mass or more, more preferably 30% by mass or more, from the viewpoint of obtaining an insulating layer with a low coefficient of thermal expansion. The upper limit of the content of the inorganic filler in the thermosetting resin composition is preferably 85% by mass or less, more preferably 80% by mass or less, from the viewpoint of mechanical strength, particularly elongation, of the insulating layer.

-(d) thermoplastic resin-
Examples of thermoplastic resins include phenoxy resins, polyvinyl acetal resins, polyolefin resins, polybutadiene resins, polyimide resins, polyamideimide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polycarbonate resins, polyether resins. Examples include ether ketone resins and polyester resins, and phenoxy resins are preferred. The thermoplastic resin may be used singly or in combination of two or more.

The polystyrene equivalent weight average molecular weight of the thermoplastic resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and even more preferably in the range of 20,000 to 60,000. The polystyrene equivalent weight average molecular weight of the thermoplastic resin is measured by a gel permeation chromatography (GPC) method. Specifically, the polystyrene-equivalent weight-average molecular weight of the thermoplastic resin is measured by LC-9A/RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P/K- manufactured by Showa Denko Co., Ltd. as a column. 804L/K-804L can be calculated by using chloroform or the like as a mobile phase, measuring the column temperature at 40° C., and 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. A phenoxy resin having one or more 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. A phenoxy resin may be used individually by 1 type, and may be used in combination of 2 or more type. Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both phenoxy resins containing bisphenol A skeleton), "YX8100" (phenoxy resin containing bisphenol S skeleton), and "YX6954" ( bisphenolacetophenone skeleton-containing phenoxy resins), and in addition, "FX280" and "FX293" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.; Examples include "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482".

Examples of polyvinyl acetal resins include polyvinyl formal resins and polyvinyl butyral resins, and polyvinyl butyral resins are preferred. Specific examples of polyvinyl acetal resins include Denka Butyral 4000-2, Denka Butyral 5000-A, Denka Butyral 6000-C, and Denka Butyral 6000-EP manufactured by Denka Kogyo Co., Ltd. , S-lec BH series manufactured by Sekisui Chemical Co., Ltd., BX series (eg BX-5Z), KS series (eg KS-1), BL series, BM series and the like.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nippon Rika Co., Ltd. Specific examples of polyimide resins also include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds and tetrabasic acid anhydrides (polyimides described in JP-A-2006-37083), and polysiloxane skeletons. Examples include modified polyimides such as polyimide containing (polyimides described in JP-A-2002-12667 and JP-A-2000-319386).

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

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

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

Among them, phenoxy resin and polyvinyl acetal resin are preferable as the thermoplastic resin. Accordingly, in one preferred embodiment, the thermoplastic resin comprises one or more selected from the group consisting of phenoxy resins and polyvinyl acetal resins.

When the thermosetting resin composition contains a thermoplastic resin, the content of the thermoplastic resin is preferably 0.5% by mass to 60% by mass, more preferably 3% by mass to 50% by mass, still more preferably 5% by mass. % to 40% by mass.

-(e) curing accelerator-
Examples of curing accelerators include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. Curing accelerators, imidazole-based curing accelerators, and metallic curing accelerators are preferred, and amine-based curing accelerators, imidazole-based curing accelerators, and metallic curing accelerators are more preferred. A hardening accelerator may be used individually by 1 type, and may be used in combination of 2 or more type.

Phosphorus curing accelerators include, for example, triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate. , tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate, and triphenylphosphine and tetrabutylphosphonium decanoate are preferred.

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

Examples of imidazole 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 isocyanurate, 2-phenylimidazole isocyanurate, 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 the like, and adducts of imidazole compounds and epoxy resins, with 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole being preferred.

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

Guanidine curing accelerators include, for example, 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 and the like, with dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene being preferred.

Metal-based curing accelerators include, for example, organometallic complexes or organometallic salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of organometallic complexes include organocobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organocopper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. and the like, 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 organic metal salts include zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, and zinc stearate.

The content of the curing accelerator in the thermosetting resin composition is not particularly limited, but is preferably 0.01% by mass to 3% by mass when the total amount of non-volatile components of the epoxy resin and curing agent is 100% by mass.

-(f) flame retardant-
Examples of flame retardants include organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, and metal hydroxides. A flame retardant may be used individually by 1 type, or may use 2 or more types together.

As the flame retardant, a commercially available product such as "HCA-HQ" manufactured by Sanko Co., Ltd. may be used.

When the thermosetting resin composition contains a flame retardant, the content of the flame retardant is not particularly limited, but is preferably 0.5% by mass to 20% by mass, more preferably 0.5% by mass to 15% by mass, More preferably 0.5% by mass to 10% by mass.

-(g) organic filler-
As the thermosetting resin composition, any organic filler that can be used in 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 "EXL-2655" manufactured by Dow Chemical Japan Co., Ltd., "AC3816N" manufactured by Ganz Kasei Co., Ltd., and the like.

When the thermosetting resin composition contains an organic filler, the content of the organic filler is preferably 0.1% by mass to 20% by mass, more preferably 0.2% by mass to 10% by mass, and still more preferably is 0.3% to 5% by weight, or 0.5% to 3% by weight.

-Other ingredients-
The thermosetting resin composition may further contain other additives as necessary, and examples of such other additives include organic compounds such as organic copper compounds, organic zinc compounds and organic cobalt compounds. Resin additives such as metal compounds, thickeners, antifoaming agents, leveling agents, adhesion-imparting agents, and coloring agents are included.

From the viewpoint of producing a flexible wiring board, the thermosetting resin composition preferably further contains a polybutadiene structure, a urethane structure, an imide structure in the molecule, and a polyimide resin having a phenol structure at the end of the molecule. When the polyimide resin is contained, the content is preferably 10% by mass to 85% by mass, more preferably 15% by mass to 50% by mass, and still more preferably 20% by mass to 30% by mass.

Details of the polyimide can be referred to the description of International Publication No. WO 2008/153208, the content of which is incorporated herein.

The thickness of the thermosetting resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, and still more preferably 40 μm or less or 20 μm or less, from the viewpoint of thinning the wiring board. Although the lower limit of the thickness of the thermosetting resin composition layer is not particularly limited, it is preferably 2 μm or more, more preferably 5 μm or more.

The minimum melt viscosity of the thermosetting resin composition layer in the adhesive sheet is preferably 9000 poise (900 Pa s) or less, more preferably 8000 poise (800 Pa s) or less, from the viewpoint of obtaining good wiring embedding properties, and 4000 poise (400 Pa s) or less. ·s) or less, 3500 poise (350 Pa·s) or less, or 3000 poise (300 Pa·s) or less is more preferable. The lower limit of the lowest melt viscosity is preferably 100 poise (10 Pa·s) or more, more preferably 200 poise (20 Pa·s) or more, and even more preferably 250 poise (25 Pa·s) or more.

The minimum melt viscosity of the thermosetting resin composition layer refers to the minimum viscosity exhibited by the thermosetting resin composition layer when the resin of the thermosetting resin composition layer melts. Specifically, when the thermosetting resin composition layer is heated at a constant rate of temperature rise to melt the resin, the melt viscosity decreases as the temperature rises in the initial stage, and then melts as the temperature rises beyond a certain level. Viscosity rises. The minimum melt viscosity refers to the melt viscosity at such minimum point. The minimum melt viscosity of the thermosetting resin composition layer can be measured by a dynamic viscoelasticity method, for example, measured according to the method described in <Measurement of minimum melt viscosity of thermosetting resin composition layer> described later can do.

<(ii) resin film layer>
The adhesive sheet includes (ii) a resin film layer. In the present invention, it is possible to manufacture a flexible wiring board by using an adhesive sheet having a resin film layer.

The resin film layer is not particularly limited as long as it can be bent to manufacture a flexible wiring board. Examples include polybenzimidazole, aramid, polyamideimide, polyetherimide, and the like.

The glass transition temperature of the resin film layer is preferably 150° C. or higher, more preferably 170° C. or higher, and even more preferably 200° C. or higher or 250° C. or higher. Although the upper limit is not particularly limited, it is generally 500° C. or less. The glass transition temperature of the resin film layer can be measured according to the method described in JIS K 7179. Specifically, it can be measured using thermomechanical analysis (TMA), dynamic mechanical analysis (DMA), or the like. can. Examples of thermal mechanical analysis (TMA) include TMA-SS6100 (manufactured by Seiko Instruments Inc.) and TMA-8310 (manufactured by Rigaku Corporation). Dynamic mechanical analysis (DMA) includes, for example, DMS-6100 (manufactured by Seiko Instruments Inc.) and the like. Further, when the glass transition temperature is higher than the decomposition temperature and the glass transition temperature is not actually observed, the decomposition temperature can be used as a reference instead of the glass transition temperature. The term "decomposition temperature" as used herein is defined as the temperature at which the mass reduction rate is 5% when measured according to the method described in JIS K7120.

The linear thermal expansion coefficient of the resin film layer is preferably 40 ppm/°C or less, more preferably 30 ppm/°C or less, and even more preferably 20 ppm/°C or less, 15 ppm/°C or less, 10 ppm/°C or less, or 5 ppm/°C or less. The lower limit is preferably -20 ppm/°C or higher, more preferably -15 ppm/°C or higher, and more preferably -10 ppm/°C or higher, from a practical viewpoint.

The surface of the resin film layer may be corona treated, plasma treated, or UV treated. In a preferred embodiment, (i) the surface of the resin film layer on the side to be bonded to the thermosetting resin composition layer is corona-treated, plasma-treated, or UV-treated. By using such a resin film layer, the adhesion between the resin film layer and the thermosetting resin composition layer can be enhanced. The treatment conditions for corona treatment, plasma treatment, or UV treatment may be appropriately determined according to the material of the resin film layer. In addition, (iii) the surface of the resin film layer on the side to be bonded to the thermosetting resin composition layer may be corona-treated, plasma-treated, or UV-treated.

Commercially available products may be used for the resin film layer, for example, "Upilex" manufactured by Ube Industries, Ltd., "Kapton" manufactured by Toray DuPont Co., Ltd., "Pomilan" manufactured by Arakawa Chemical Industries, Ltd., and Kaneka Corporation. "Apical" manufactured by Toray Industries, Ltd., "Mictron" manufactured by Toray Industries, Ltd., and "Aramica" manufactured by Asahi Chemical Industry Co., Ltd. as aramid films, "Vecstar" manufactured by Kuraray Co., Ltd. as liquid crystal polymer films, and " Viac", and polyether ether ketone such as "Sumilite FS-1100C".

The thickness of the resin film layer is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, 40 μm or less, or 20 μm or less, from the viewpoint of thinning the wiring board. Although the lower limit of the thickness of the resin film layer is not particularly limited, it is preferably 1 µm or more, more preferably 2 µm or more, from the viewpoint of the mechanical strength of the wiring board.

<(iii) Metal foil or thermosetting resin composition layer>
The adhesive sheet may further contain (iii) a metal foil or a thermosetting resin composition layer. The adhesive sheet preferably includes (i) a thermosetting resin composition layer, (ii) a resin film layer, and (iii) a metal foil or thermosetting resin composition layer in this order.

Examples of the metal foil include copper foil and aluminum foil, with copper foil being preferred. As the copper foil, a foil made of a single metal of copper may be used, and 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 metal foil may be a laminated foil in which two or more metal foils are laminated.

The metal foil (ii) may be provided with an adhesive layer on the side to be bonded to the resin film layer. The adhesive layer is not particularly limited, and known adhesives and adhesives can be used.

The thermosetting resin composition layer is the same as (i) the thermosetting resin composition layer, and the preferred range is also the same.

(iii) The thickness of the metal foil or thermosetting resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, still more preferably 60 μm or less, 40 μm or less, or 20 μm or less, from the viewpoint of thinning the wiring board, or 10 μm or less. Although the lower limit of the thickness is not particularly limited, it can be usually 1 μm or more, 2 μm or more, or 3 μm or more.

The adhesive sheet may contain other layers in addition to the layers (i) to (iii) above. For example, the adhesive sheet may have a protective film layer, which will be described later, on the outermost surface.

<Method for manufacturing adhesive sheet>
The method for producing the adhesive sheet is not particularly limited as long as the adhesive sheet comprising (i) the thermosetting resin composition layer and (ii) the resin film layer in this order can be obtained. An example of a method for producing an adhesive sheet in which the adhesive sheet includes the layer (iii) and the layer (iii) is a thermosetting resin composition layer is shown below. First, a resin varnish is prepared by dissolving (i) a thermosetting resin composition for the thermosetting resin composition layer in an organic solvent, and this resin varnish is applied onto a protective film described later using a die coater or the like. do. The applied resin varnish is dried to form (i) a thermosetting resin composition layer to obtain a laminate 1 . Then, the (ii) resin film layer is laminated on the (i) thermosetting resin composition layer of the laminate 1 to obtain the laminate 2 . Separately, prepare a resin varnish by dissolving (iii) a thermosetting resin composition for the thermosetting resin composition layer in an organic solvent, and apply this resin varnish to a protective film described later using a die coater or the like. do. The applied resin varnish is dried (iii) to form a thermosetting resin composition layer to obtain a laminate 3 . An adhesive sheet is obtained by laminating the laminate 2 and the laminate 3 so that (ii) the resin film layer and (iii) the thermosetting resin composition layer are bonded. When manufacturing an adhesive sheet in which the layer (iii) is a metal foil, a laminate 3' in which (ii) a resin film layer and (iii) a metal foil are laminated may be used. An adhesive sheet is obtained by laminating the laminate 1 and the laminate 3′ such that (i) the thermosetting resin composition layer and (ii) the resin film layer are bonded.

Organic solvents include, for example, ketones such as acetone, methyl ethyl ketone (MEK) and cyclohexanone, acetic acid esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve and butyl carbitol. carbitols, aromatic hydrocarbons such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide (DMAc) and N-methylpyrrolidone. An organic solvent may be used individually by 1 type, and may be used in combination of 2 or more type.

Drying may be carried out by a known method such as heating or blowing hot air. Although the drying conditions are not particularly limited, drying is performed so that the content of the organic solvent in the thermosetting resin composition layer is 10% by mass or less, preferably 5% by mass or less. Depending on the boiling point of the organic solvent in the resin varnish, for example, when using a resin varnish containing 30% by mass to 60% by mass of the organic solvent, it is dried at 50 ° C. to 150 ° C. for 3 minutes to 15 minutes to heat cure. A flexible resin composition layer can be formed.

(i) the thermosetting resin composition layer (ii) the surface not bonded to the resin film layer (that is, the surface opposite to the resin film layer), and (ii) the resin film layer (i) thermosetting A protective film can be further laminated on the surface that is not bonded to the thermosetting resin composition layer (that is, the surface opposite to the thermosetting resin composition layer). Further, when the adhesive sheet includes (iii) a metal foil or a thermosetting resin composition layer, (iii) the surface of the metal foil or thermosetting resin composition layer that is not bonded to the (ii) resin film layer (i.e. , the surface opposite to the resin film layer), and (ii) the surface of the thermosetting resin composition layer that is not bonded to the resin film layer, a protective film can be further laminated. By laminating the protective film, the surfaces of the layers (i) and (ii) (the layers (i) and (iii) when the layer (iii) is included) are prevented from being dusted or scratched. can be prevented. The adhesive sheet can be wound into a roll and stored. When the adhesive sheet has a protective film, it can be used by peeling off the protective film.

A film made of a plastic material is preferable as the protective film.

Examples of plastic materials include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate (hereinafter sometimes abbreviated as "PEN"); polyolefins such as polyethylene and polypropylene; Polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylic such as polymethyl methacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, polyimide, etc. be done. Among them, polyethylene terephthalate, polyethylene naphthalate, and polypropylene are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

The protective film includes (i) a thermosetting resin composition layer or (ii) a resin film layer ((iii) a metal foil or a thermosetting resin composition layer, (i) a thermosetting resin composition layer or (iii) The surface to be bonded with the metal foil or thermosetting resin composition layer) may be subjected to matte treatment or corona treatment.

In addition, as the protective film, (i) a thermosetting resin composition layer, or (ii) a resin film layer ((iii) a metal foil or a thermosetting resin composition layer when the layer (iii) is included) and A support with a release layer having a release layer on the surface to be bonded may be used. The release agent used in the release layer of the release layer-attached support includes, for example, 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, a commercially available product may be used, for example, "SK-1" manufactured by Lintec Corporation, which is a PET film having a release layer containing an alkyd resin release agent as a main component. , “AL-5”, “AL-7”, “Lumirror T6AM” manufactured by Toray Industries, Inc., and the like.

Although the thickness of the protective film is not particularly limited, it is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. When a release layer-attached support is used, the thickness of the release layer-attached support as a whole is preferably within the above range.

Regarding the adhesive sheet, the description in JP-A-2014-187091 can be referred to, the content of which is incorporated herein.

The adhesive sheet in the present invention exhibits good embedding properties. In one embodiment, the adhesive sheet can be laminated on the wiring layer without voids when laminating on the substrate with the wiring layer. The embeddability can be measured according to the method described in "(2-2) Observation of embeddability" in Examples described later.

Since the adhesive sheet is provided with a resin film layer, it exhibits a characteristic of being foldable even after thermosetting. The breaking elongation of the adhesive sheet after thermosetting is preferably 2% or more, more preferably 3% or more, and still more preferably 5% or more. Although there is no particular upper limit, it is 10% or less. The breaking elongation can be measured according to the method described in <Measurement of Breaking Elongation> below. Since the wiring board of the present invention is manufactured using such an adhesive sheet, it can be a flexible wiring board. The elongation at break of the adhesive sheet after thermosetting means the elongation at break of (i) the thermosetting resin composition layer of the adhesive sheet.

[Method for manufacturing wiring board]
The wiring board manufacturing method of the present invention comprises:
(1) A step of preparing a substrate with a wiring layer having a substrate and a wiring layer provided on at least one surface of the substrate;
(2) An adhesive sheet containing (i) a thermosetting resin composition layer and (ii) a resin film layer is placed on a substrate with a wiring layer so that the wiring layer is embedded in the (i) thermosetting resin composition layer. lamination on the material and thermosetting to form an insulating layer;
(3) forming a via hole in the insulating layer;
(4) forming a conductor layer; and (5) removing the base material.

Manufacture of a wiring board in which the adhesive sheet (iii) contains a metal foil or a thermosetting resin composition layer and (iii) the metal foil or the thermosetting resin composition layer is a thermosetting resin composition layer The method will be described as a first embodiment, and the wiring board manufacturing method in which the layer (iii) of the adhesive sheet is a metal foil will be described as a second embodiment, but the present invention is not limited to this.

1. First Embodiment <Step (1)>
Step (1) is a step of preparing a substrate with a wiring layer, which has a substrate and a wiring layer provided on at least one surface of the substrate. As an example is shown in FIG. 1, a substrate 10 with a wiring layer has a first metal layer 12 and a second metal layer 13, which are part of the substrate 11, on both sides of the substrate 11, respectively. A wiring layer 14 is provided on the surface of the second metal layer 13 opposite to the surface facing the substrate 11 .

In the details of step (1), a dry film (photosensitive resist film) is laminated on a base material, exposed under predetermined conditions using a photomask, and developed to form a patterned dry film. After forming a wiring layer by electroplating using the developed patterned dry film as a plating mask, the patterned dry film is peeled off.

Materials used for the first and second metal layers are not particularly limited. In a preferred embodiment, the first and second metal layers are preferably chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper from the viewpoint of cost, etching, strippability, etc., and copper is preferred. more preferred.

The substrate is not particularly limited as long as steps (1) to (5) can be carried out. Examples of the base material include substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, etc. A metal layer such as copper foil is formed on the substrate surface. may

The dry film is not particularly limited as long as it is a photosensitive dry film made of a photoresist composition, and for example, dry films such as novolak resins and acrylic resins can be used. A commercially available dry film may be used, for example, a dry film with a PET film, "ALPHO 20A263" manufactured by Nikko Materials Co., Ltd. may be used. The dry film may be laminated on one side of the substrate, or may be laminated on both sides of the substrate as in the second embodiment described later.

The conditions for laminating the base material and the dry film are the same as the conditions for laminating the adhesive sheet so as to be embedded in the wiring layer in step (2) described below, and the preferred ranges are also the same.

After laminating the dry film on the substrate, exposure and development are performed using a photomask under predetermined conditions in order to form a desired pattern on the dry film.

The line (circuit width)/space (width between circuits) ratio of the wiring layer is not particularly limited, but is preferably 20/20 μm or less (that is, the pitch is 40 μm or less), more preferably 15/15 μm or less (pitch is 30 μm or less), More preferably, it is 10/10 μm or less (pitch of 20 μm or less). Although the lower limit of the line/space ratio of the wiring layer is not particularly limited, it is preferably 0.5/0.5 μm or more, more preferably 1/1 μm or more. The pitch need not be the same throughout the wiring layer.

The minimum pitch of the wiring layers may be 40 μm or less, 30 μm or less, or 20 μm or less.

After forming the dry film pattern, a wiring layer is formed and the dry film is peeled off. Here, the wiring layer can be formed by plating using a dry film having a desired pattern formed thereon as a plating mask.

The conductor material used for the wiring layer is not particularly limited. In a preferred embodiment, the wiring layer contains 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 wiring layer may be a single metal layer or an alloy layer. 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 nickel alloys and copper-titanium alloys). Among them, from the viewpoint of versatility of wiring layer formation, cost, ease of patterning, etc., single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, nickel-chromium alloys, copper- Nickel alloys and copper/titanium alloy alloy layers are preferred, and single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or nickel/chromium alloy alloy layers are more preferred, and copper single metal layers are preferred. A metal layer is more preferred.

The thickness of the wiring layer is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm, still more preferably 10 to 20 μm, or 15 μm, depending on the desired wiring board design.

After forming the wiring layer, the dry film is peeled off. Stripping of the dry film can be carried out by using an alkaline stripping solution such as a sodium hydroxide solution. If necessary, a desired wiring pattern can be formed by removing unnecessary wiring patterns by etching or the like. The pitch of the wiring layers to be formed is as described above.

<Step (2)>
The step (2) is a step of laminating an adhesive sheet on a base material with a wiring layer such that the wiring layer is embedded in the (i) thermosetting resin composition layer, followed by thermal curing to form an insulating layer. be. Since the adhesive sheet of the present invention exhibits good embeddability, it can be laminated on a substrate with a wiring layer in a void-free state. As an example is shown in FIG. 2, the wiring layer 14 of the base material with the wiring layer obtained in the above step (1) is laminated so as to be embedded in the (i) thermosetting resin composition layer 21 of the adhesive sheet 20. to thermally cure the (i) thermosetting resin composition layer of the adhesive sheet 20 . The adhesive sheet 20 is formed by laminating (i) a thermosetting resin composition layer 21, (ii) a resin film layer 22, and (iii) a metal foil or thermosetting resin composition layer 23 in this order. That is, the adhesive sheet 20 has at least a three-layer structure. In addition, the adhesive sheet 20 (iii) may have a protective film 24 on the surface of the metal foil or thermosetting resin composition layer 23 opposite to the surface on which the resin film layer 22 is provided.

The adhesive sheet 20 used in the first embodiment has a three-layer structure, but the adhesive sheet 20 is not limited to this. For example, (i) a thermosetting resin composition layer, (ii) a resin An adhesive sheet 20 having a two-layer structure in which film layers are laminated in order may be used. In this case, the layer 23 of (iii) in the figure is omitted.

First, as an example is shown in FIG. 2, (i) the thermosetting resin composition layer 21 of the adhesive sheet 20 is laminated on the substrate with the wiring layer so that the wiring layer 14 is embedded.

Lamination of the wiring layer and the adhesive sheet can be carried out by, for example, heating and press-bonding the adhesive sheet to the wiring layer from the layer (iii) side after removing the protective film of the adhesive sheet. Examples of the member for thermocompression bonding of the adhesive sheet to the wiring layer (hereinafter also referred to as “thermocompression member”) include heated metal plates (such as SUS end plates) and metal rolls (SUS rolls). Instead of directly pressing the thermocompression member onto the adhesive sheet, it is preferable to press through an elastic material such as heat-resistant rubber so that the adhesive sheet can sufficiently follow the unevenness of the surface of the wiring layer.

Lamination of the wiring layer and the adhesive sheet may be carried out by a vacuum lamination method after removing the protective film of the adhesive sheet. In the vacuum lamination method, the thermocompression temperature is preferably in the range of 60° C. to 160° C., more preferably 80° C. to 140° C., and the thermocompression pressure is preferably 0.098 MPa to 1.77 MPa, more preferably 0. .29 MPa to 1.47 MPa, and the heat pressing time is preferably 20 seconds to 400 seconds, more preferably 30 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 13 hPa or less.

Lamination can be done with a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressurized laminator manufactured by Nikko Materials Co., Ltd., a vacuum pressurized laminator manufactured by Meiki Seisakusho Co., Ltd., and a vacuum applicator manufactured by Nichigo-Morton Co., Ltd. be done.

After lamination, the laminated adhesive sheets may be smoothed under normal pressure (atmospheric pressure), for example, by pressing a thermocompression member from the layer (iii) side. Pressing conditions for the smoothing treatment may be the same as the thermocompression bonding conditions for the lamination described above. Smoothing treatment can be performed with a commercially available laminator. Lamination and smoothing may be performed continuously using the above-mentioned commercially available vacuum laminator.

After the wiring layer is (i) laminated on the base material with the wiring layer so as to be embedded in the thermosetting resin composition layer, (i) the thermosetting resin composition layer is thermally cured to form an insulating layer. . (i) The thermosetting conditions for the thermosetting resin composition layer are not particularly limited, and the conditions usually employed when forming the insulating layer of the wiring board may be used. In the first embodiment, when the layer (iii) exists, the layer (iii) is also an insulating layer.

For example, the thermosetting conditions for the thermosetting resin composition layer vary depending on the type of the thermosetting resin composition, etc., but the curing temperature is in the range of 120 ° C. to 240 ° C. (preferably in the range of 150 ° C. to 220 ° C., more preferably in the range of 170° C. to 200° C.), and the curing time can be in the range of 5 minutes to 120 minutes (preferably 10 minutes to 100 minutes, more preferably 15 minutes to 90 minutes).

Before thermosetting the thermosetting resin composition layer, the thermosetting resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermosetting the thermosetting resin composition layer, heat curing at a temperature of 50 ° C. or higher and less than 120 ° C. (preferably 60 ° C. or higher and 110 ° C. or lower, more preferably 70 ° C. or higher and 100 ° C. or lower) The flexible resin composition layer may be preheated for 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

The protective film of the adhesive sheet may be peeled off after the adhesive sheet is laminated on the substrate with the wiring layer and thermally cured, or the protective film may be peeled off before laminating the adhesive sheet on the substrate with the wiring layer. good. Moreover, after the step (3) and before the roughening treatment step, the protective film may be peeled off.

The thickness of the insulating layer is the same as (i) the thickness of the thermosetting resin composition layer or (iii) the thickness of the layer, and the preferred range is also the same.

<Step (3)>
Step (3) is a step of forming via holes in the insulating layer. Formation of via holes is preferably performed by laser irradiation. Specifically, as shown in an example in FIG. 3, in step (3), after the protective film 24 is peeled off, laser irradiation is performed from the surface side of the adhesive sheet 20 to form the insulating layer 23, the resin film layer 22, and the insulating layer. A via hole 31 is formed through the layer 21 to expose the wiring layer 14 . In addition, before peeling off the protective film 24, laser irradiation is performed from the surface side of the adhesive sheet to penetrate the protective film 24, the insulating layer 23, the resin film layer 22, and the insulating layer 21 to expose the wiring layer 14. 31 may be formed, and the protective film 24 may be peeled off after the via holes 31 are formed.

This laser irradiation can be performed using any suitable laser processing machine using a carbon dioxide gas laser, a YAG laser, an excimer laser, or the like as a light source. Laser processing machines that can be used include, for example, CO ₂ laser processing machine "LC-2k212/2C" manufactured by Via Mechanics Co., Ltd., 605GTWIII (-P) manufactured by Mitsubishi Electric Corporation, and manufactured by Matsushita Welding Systems Co., Ltd. laser processing machine.

The conditions for laser irradiation are not particularly limited, and laser irradiation can be carried out by any suitable process according to a conventional method according to the means selected.

The shape of the via hole, that is, the shape of the contour of the opening when viewed in the extending direction is not particularly limited, but is generally circular (substantially circular). Hereinafter, the "diameter" of the via hole means the diameter of the contour of the opening when viewed in the extending direction. In this specification, the top diameter refers to the diameter of the contour of the via hole on the insulating layer 23 side, and the bottom diameter refers to the diameter of the contour of the via hole on the wiring layer 14 side.

It is preferable to form the via hole such that the top diameter r1 of the via hole is 120 μm or less, preferably 90 μm or less.

It is preferable to form the via hole such that the top diameter r1 of the via hole is larger than the bottom diameter r2 of the via hole 31 .

In this way, the embedding of the via hole is improved, and the generation of voids can be suppressed. As a result, the reliability of electrical connection by filled vias, which will be described later, can be improved.

After forming the via hole, a so-called desmear process, which is a process for removing smear in the via hole, may be performed. When step (4) described later is performed by a plating step, the via hole may be subjected to, for example, a wet desmear treatment, and when step (4) is performed by a sputtering step, for example, a plasma treatment step may be performed. You may perform a dry desmear process, such as. Moreover, the desmearing process may serve as the roughening treatment process.

Step (5) A step of roughening may be included before the step of forming the conductor layer. The roughening treatment is performed on the via holes and the adhesive sheet, and the procedure and conditions of the roughening treatment are not particularly limited. can be adopted. An example of dry roughening treatment is plasma treatment, and an example of wet roughening treatment is a method in which swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution are performed in this order. is mentioned.

In the wet roughening treatment, for example, the insulating layer 23 can be roughened by performing swelling treatment with a swelling liquid, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution in this order. The swelling liquid is not particularly limited, but may be an alkaline solution, a surfactant solution, or the like, preferably an alkaline solution, and more preferably a sodium hydroxide solution or a potassium hydroxide solution. Examples of commercially available swelling liquids include Swelling Dip Securigans P and Swelling Dip Securigans SBU manufactured by Atotech Japan.

The swelling treatment with the swelling liquid is not particularly limited, but can be performed, for example, by immersing the insulating layer 23 in the swelling liquid at 30.degree. C. to 90.degree. C. for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer 23 to an appropriate level, it is preferable to immerse the insulating layer 23 in the swelling liquid at 40° C. to 80° C. for 5 seconds to 15 minutes. Examples of the oxidizing agent include, but are not limited to, 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 permanganate solution is preferably performed by immersing the insulating layer 23 in an oxidizing agent solution heated to 60.degree. C. to 80.degree. C. for 10 to 30 minutes. Further, the permanganate concentration in the alkaline permanganate solution is preferably 5% by mass to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as Concentrate Compact P and Dosing Solution Securigans P manufactured by Atotech Japan Co., Ltd. Moreover, as a neutralizing liquid, an acidic aqueous solution is preferable, and as a commercial product, for example, Reduction Solution Security P manufactured by Atotech Japan Co., Ltd. can be mentioned.

The treatment with the neutralizing solution can be carried out by immersing the treated surface roughened with the oxidant solution in the neutralizing solution at 30° C. to 80° C. for 5 to 30 minutes. From the viewpoint of workability, etc., a method of immersing an object roughened with an oxidizing agent solution in a neutralizing solution at 40° C. to 70° C. for 5 to 20 minutes is preferable.

<Step (4)>
Step (4) is a step of forming a conductor layer. A conductor material constituting the conductor layer is not particularly limited. In a preferred embodiment, it can be made of the same material as the conductor material used for the wiring pattern, preferably copper.

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

The thickness of the conductor layer is generally 3 μm to 35 μm, preferably 5 μm to 30 μm, depending on the desired circuit board design.

The conductor layer can be formed by any suitable conventionally known method such as plating, sputtering, vapor deposition, etc., and is preferably formed by plating. In a preferred embodiment, for example, a conductor layer having a desired wiring pattern can be formed by plating the surface of the insulating layer by a conventionally known technique such as a semi-additive method or a full-additive method.

Specifically, a plating seed layer is formed by electroless plating on the surface of the insulating layer 23 (the surface of the resin film layer 22 if the layer (iii) does not exist). 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 an electroplating layer on the exposed plating seed layer by electroplating, the mask pattern is removed. After that, the unnecessary plating seed layer is removed by etching or the like, and a conductor layer having a desired wiring pattern can be formed.

As an example is shown in FIG. 4, a plating seed layer 41 is formed to be bonded to the exposed surface of the insulating layer 23 (the surface of the resin film layer 22 if the layer (iii) does not exist; the same applies hereinafter). . First, the surface of the insulating layer 23 is washed and alkaline cleaning is performed for charge adjustment. Next, a soft etching process is performed to clean the inside of the via hole 31 . Specifically, an etchant such as an aqueous solution of sodium peroxodisulfate acidified with sulfuric acid may be used under arbitrary suitable conditions. Next, a pre-dip step for adjusting the charge on the surface of the insulating layer 23 is performed in order to apply Pd (palladium) to the surface of the insulating layer 23 . Next, Pd as an activator is applied to the surface to reduce the Pd applied to the insulating layer 23 . Next, copper (Cu) is deposited on the surface of the insulating layer 23 to form the plating seed layer 41 . At this time, the plating seed layer 41 is formed so as to cover the inside of the via hole 31 , that is, the side wall and the wiring pattern 14 exposed from the via hole 31 .

As an example is shown in FIG. 5, after forming the plating seed layer 41, a mask pattern 50 is formed to partially expose the plating seed layer 41. As shown in FIG. The mask pattern 50 can be formed, for example, by bonding a dry film to the plating seed layer 41 and performing exposure, development and cleaning under predetermined conditions.

The dry film that can be used in step (4) is the same as the above dry film, and the preferred range is also the same.

As shown in an example in FIG. 6 , on the exposed plating seed layer 41 , an electroplating layer 42 is formed by electroplating under the condition that the via hole 31 is filled, and the via hole is filled by electroplating to form a filled via 61 . to form

As an example is shown in FIG. 7, the patterned conductor layer 40 is then formed by stripping and removing the mask pattern and performing flash etching under arbitrary suitable conditions to remove only the exposed plating seed layer 41 .

The conductor layer can include not only linear wiring but also electrode pads (lands) on which external terminals can be mounted, for example. Alternatively, the conductor layer may be composed only of the electrode pads.

Alternatively, the conductor layer may be formed by forming an electroplating layer and filled vias without using a mask pattern after forming the plating seed layer, and then patterning by etching.

<Step (5)>
Step (5) is a step of removing the base material to form the wiring board of the present invention, as shown in FIG. A method for removing the substrate is not particularly limited. In one preferred embodiment, the substrate is stripped from the wiring board at the interface between the first and second metal layers, and the second metal layer is etched away with, for example, an aqueous copper chloride solution.

If necessary, the substrate may be peeled off while the conductor layer 23 is protected with a protective film. The protective film is the same as the protective film used for the adhesive sheet, and the preferred range is also the same.

A wiring board in which the wiring layer 14 is embedded in the insulating layer 21 can be manufactured by the manufacturing method of the present invention. In addition, by including at least one resin film layer 22, a flexible wiring board can be obtained. If necessary, the steps (2) to (4) of forming the insulating layer and the conductor layer may be repeated to form a multilayer wiring board. When manufacturing a multilayer wiring board, at least one adhesive sheet having a resin film layer may be used. That is, the wiring board of the present invention may have at least one resin film layer even if it is a multilayer wiring board. Flexible means that the wiring board can be bent at least once without cracks or changes in resistance value.

2. Second Embodiment The second embodiment is a wiring board manufacturing method in which the layer (iii) of the adhesive sheet is a metal foil. In the drawings used for the following description, the same reference numerals are assigned to the same components as in the first embodiment, and redundant description may be omitted.

Step (1) is a step of preparing a base material with a wiring layer having a base material and a wiring layer provided on one surface of the base material, as an example is shown in FIG. The method of forming the wiring layer 14 is the same as that of the first embodiment.

The step (2) is a step of laminating the adhesive sheet on the base material with the wiring layer so that the wiring layer is embedded in the (i) thermosetting resin composition layer, followed by thermosetting. As an example is shown in FIG. 10, the wiring layer 14 of the substrate with the wiring layer obtained in the above step (1) is laminated so as to be embedded in the (i) thermosetting resin composition layer 21 of the adhesive sheet 20. to thermally cure the (i) thermosetting resin composition layer of the adhesive sheet 20 . The adhesive sheet 20 is formed by laminating (i) a thermosetting resin composition layer 21, (ii) a resin film layer 22, and (iii) a metal foil 25 in this order. Also, the adhesive sheet 20 may (iii) have a protective film 24 on the surface of the metal foil 25 opposite to the surface on which the resin film layer 22 is provided.

In the step (3), as shown in an example in FIG. 11, it is preferable to irradiate the thermally cured adhesive sheet 20 with a laser to form via holes 31 in the thermally cured adhesive sheet 20 . After step (3) is completed, a roughening treatment is performed.

Step (4) is a step of forming a conductor layer. In the second embodiment, since the layer (iii) of the adhesive sheet is a metal foil, it is preferable to form a conductor layer having a desired wiring pattern by a conventionally known technique such as a subtractive method.

In one preferred embodiment of step (4), first, an etching resist pattern is formed on the surface of the metal foil to expose a portion of the metal foil corresponding to the desired wiring pattern. The etching resist pattern can be formed, for example, by bonding an etching resist film to a metal foil and exposing and developing the film under predetermined conditions.

After forming the etching resist pattern, the exposed metal foil portion is removed by etching or the like, and then the etching resist pattern is peeled off and removed, whereby the conductor layer 43 having the desired wiring pattern can be formed.

As the etching resist film, the same one as the dry film can be used, and the preferred range is also the same.

Step (5) is a step of removing the base material to form the wiring board of the present invention, as shown in an example in FIG.

3. Third Embodiment In the first and second embodiments, a wiring board is manufactured from a base material with a wiring layer having a wiring layer on one side. It is the same as the first embodiment and the second embodiment except that the wiring board is manufactured from the base material with the wiring layer. In the drawings used for the following description, the same components are denoted by the same reference numerals, and redundant description may be omitted.

Step (1) is a step of preparing a base material with wiring layers having a base material and wiring layers provided on both sides of the base material, as an example is shown in FIG. 13 . The method of forming the wiring layer 14 is the same as in the first embodiment and the second embodiment, and the wiring layers provided on both sides of the base material may be formed simultaneously to prepare a base material with wiring layers. After forming the layer, the other wiring layer may be formed to prepare the base material with the wiring layer. Further, each wiring layer may have the same pattern or different patterns.

In the step (2), as shown in an example in FIG. 14, an adhesive sheet is applied to both sides of the base material with the wiring layer so that the wiring layer is embedded in the (i) thermosetting resin composition layer. It is a step of laminating each on a base material with a layer and heat-curing it. The two adhesive sheets used may be the same adhesive sheet or different adhesive sheets.

In step (3), as shown in an example in FIG. 15, laser irradiation is performed from the heat-cured adhesive sheet side on both sides of the base material with the wiring layer to form via holes in the heat-cured adhesive sheet. is preferred. The via holes may be formed at the same time, or after one via hole is formed, the other via hole may be formed.

Before the step (4), a step of roughening both surfaces of the base material with the wiring layer may be included, and the surfaces of the two insulating layers 23 are roughened. The roughening treatments may be performed simultaneously, or one roughening treatment may be followed by the other roughening treatment.

In step (4), conductor layers are formed on both sides of the substrate with wiring layers. As an example is shown in FIG. 16, a plating seed layer 41 is formed on the insulating layer 23 after the roughening treatment. After forming the plating seed layer 41, as shown in FIG. 17, a mask pattern 50 is formed to partially expose the plating seed layer 41. As shown in FIG. Then, an electroplating layer 42 is formed, and the via holes are filled by electroplating to form filled vias 61 . As an example is shown in FIG. 19, the mask pattern is removed and a conductor layer is formed. Details of formation of the conductor layer can be performed in the same manner as in the first embodiment. Also, the two conductor layers may be formed at the same time, or after forming one conductor layer, the other conductor layer may be formed.

When the layer (iii) of the adhesive sheet is a metal foil, the conductor layer may be formed by the same method as in the second embodiment. Alternatively, one conductor layer may be formed in the same manner as in the first embodiment, and the other conductor layer may be formed in the same manner as in the second embodiment.

Step (5) is a step of removing the base material to form the wiring board of the present invention, as an example is shown in FIG. In the third embodiment, it is possible to manufacture two types of wiring boards at the same time.

[Wiring board]
A wiring board of the present invention is characterized by comprising a resin film layer, an insulating layer, and an embedded wiring layer embedded in the insulating layer. In addition, the description which overlaps with the content mentioned above may be abbreviate|omitted.

The wiring board of the present invention can be manufactured, for example, by the wiring board manufacturing method of the present invention including the steps (1) to (5). As described above, the wiring board of the present invention has the embedded wiring layer 14, the insulating layer 21, and the resin film layer 22 laminated in this order, as shown in FIGS. An insulating layer 23 and a conductor layer 40 are provided on the surface of the resin film layer 22 not bonded to the insulating layer (that is, on the surface opposite to the resin film layer 22). The embedded wiring layer 14 is joined to the conductor layer 40 through the filled via 61 . Moreover, as an example is shown in FIG. 12, a mode in which the conductor layer 43 and the embedded wiring layer 14 are joined may be employed.

The embedded wiring layer refers to a wiring layer (wiring layer 14) embedded in the insulating layer 21 as long as a conductor connection with a component such as a semiconductor chip is possible. The embedded wiring layer is usually embedded in the insulating layer so that the protrusion height on the side opposite to the side on which the adhesive sheet is laminated is substantially 0 (zero), usually -1 μm to +1 μm. is

The wiring board of the present invention may be a multilayer wiring board, and in this case, at least one resin film layer 22 bonded to the insulating layer 21 may be provided. The resin film layer 22 may be provided on the surface of the insulating layer 21 that is not bonded to the embedded wiring layer 14, as shown in an example in FIG. A resin film layer 22 may be provided on the surface that is joined to the electroplating layer. Moreover, as an example is shown in FIG. 23, two or more resin film layers 22 may be provided. 21 and 22 are obtained by using an adhesive sheet having a two-layer configuration of thermosetting resin composition layers as an adhesive sheet other than the adhesive sheet including the resin film layer 22. Therefore, although the insulating layer 21 and the insulating layer 23 are laminated, an adhesive sheet having a single thermosetting resin composition layer is used as an adhesive sheet other than the adhesive sheet including the resin film layer 22. to obtain a wiring board, and only the insulating layer 21 (or the insulating layer 23) may be provided.

FIGS. 21 to 23 show a multilayer wiring board manufactured using an adhesive sheet that further includes a layer (iii) and the layer (iii) is a thermosetting resin composition layer, but ( It may be a multilayer wiring board manufactured using an adhesive sheet in which the layer of iii) is a metal foil, and an adhesive sheet that does not contain the layer of (iii), that is, (i) a thermosetting resin composition layer, and ( ii) It may be a multilayer wiring board manufactured using an adhesive sheet containing a resin film layer.

The wiring board obtained by the wiring board manufacturing method of the present invention exhibits good bendability. In one embodiment, no abnormalities such as cracks occur on both sides of the bent portion after the bending test. This bending test can be measured, for example, according to the method described in <Bending test (crack)> described later. Also, in one embodiment, the change in resistance after the bending test is 50% or less. The change in resistance after the bending test can be measured, for example, according to the method described in <Bending test (change in resistance)> below.

The wiring board obtained by the wiring board manufacturing method of the present invention exhibits good reflow behavior. In one embodiment, the reflow warpage behavior is 50 μm or less. The reflow warpage behavior can be measured, for example, according to the method described in <Evaluation of reflow warpage behavior>.

[Semiconductor device]
A semiconductor device of the present invention includes the wiring board of the present invention. The semiconductor device of the present invention can be manufactured using the wiring board of the present invention.

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

The semiconductor device of the present invention can be manufactured by mounting a component (semiconductor chip) on a conductive portion of a printed wiring board. A "conducting part" is a "part where an electric signal is transmitted on a printed wiring board", and the place may be a surface or an embedded part. Also, the semiconductor chip is not particularly limited as long as it is an electric circuit element made of a semiconductor.

The method of mounting the semiconductor chip when manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively. Examples include a mounting method using a buildup layer (BBUL), a mounting method using an anisotropic conductive film (ACF), and a mounting method using a non-conductive film (NCF). Here, "a mounting method using a build-up layer without bumps (BBUL)" refers to a "mounting method in which a semiconductor chip is directly embedded in a concave portion of a printed wiring board and the semiconductor chip and wiring on the printed wiring board are connected." is.

EXAMPLES The present invention will be specifically described below by way of examples, but the present invention is not limited to these examples. In the following description, "parts" and "%" mean "mass parts" and "mass%", respectively, unless otherwise specified. The thickness of each layer of the adhesive sheet was measured using a contact layer thickness gauge (MCD-25MJ, manufactured by Mitutoyo Corporation).

<Preparation of evaluation substrate>
(1) Step of preparing a base material with a wiring layer having a base material and a wiring layer provided on at least one surface of the base material (1-1) Lamination of a dry film on a base material (core substrate) As a core substrate, glass cloth-based epoxy resin double-sided copper-clad laminate (layer configuration: Mitsui Kinzoku Co., Ltd. Micro Syn MT-Ex (copper foil thickness 3 μm / carrier copper foil 18 μm), Panasonic Corporation An “R1515A” substrate (thickness: 0.2 mm) and Microcyn MT-Ex manufactured by Mitsui Kinzoku Mining Co., Ltd. (carrier copper foil: 18 μm/thickness: 3 μm copper foil) were prepared. A dry film with a PET film (manufactured by Hitachi Chemical Co., Ltd., high resolution type, thickness 15 μm) is placed on both sides of the 3 μm thick copper foil of the laminate, and the dry film is a 3 μm thick copper foil. It laminated|stacked using the batch-type vacuum pressurization laminator (2 stage buildup laminator "CVP700" by Nikko-Materials Co., Ltd.) so that it might join. Lamination of the dry film was carried out by pressure bonding for 20 seconds at a temperature of 70° C. and a pressure of 0.1 MPa after reducing the pressure to 13 hPa or less for 30 seconds.

(1-2) Formation of pattern A glass mask (photomask) having the pattern shown below is placed on a PET film that is a protective layer of a dry film, and is irradiated with a UV lamp at an intensity of 150 mJ/cm ² . irradiated. After the UV irradiation, the PET film of the dry film was peeled off, and a 30° C. 1% sodium carbonate aqueous solution was sprayed for 30 seconds at a jet pressure of 0.15 MPa. After that, the film was washed with water, and the dry film was developed (patterned).

Wiring pattern of the glass mask:
L/S=10 μm/10 μm, that is, a comb tooth pattern (wiring length 10 mm, 16 lines) with a wiring pitch of 20 μm is formed at intervals of 10 mm.

(1-3) Formation of Wiring Layer After developing the dry film, electrolytic copper plating was performed to a thickness of 8 μm to form a wiring layer. Next, a 3% sodium hydroxide solution at 50°C was sprayed at a jet pressure of 0.2 MPa, the dry film was peeled off, washed with water, and dried at 150°C for 30 minutes.

(2) Step of laminating an adhesive sheet on a base material with a wiring layer so that the wiring layer is embedded in the (i) thermosetting resin composition layer and thermally curing (2-1) Lamination of the adhesive sheet Examples And the protective film of the adhesive sheet prepared in Comparative Example (25 μm thick release PET film in Example 1, Examples 2 and 3, 20 μm thick protective film in Comparative Examples 1 and 2) was peeled off, batch type Using a vacuum pressurized laminator (2-stage build-up laminator "CVP700" manufactured by Nikko Materials Co., Ltd.), the thermosetting resin composition layer was buried and laminated on both sides of the wiring pattern so that it was bonded to the wiring pattern. Lamination was carried out by pressure bonding for 30 seconds at 110° C. and a pressure of 0.74 MPa after reducing the pressure to 13 hPa or less for 30 seconds. Then, the laminated adhesive sheets were hot-pressed for 60 seconds at 110° C. under atmospheric pressure and a pressure of 0.5 MPa for smoothing. Assume that this is an evaluation substrate A.

(2-2) Observation of embeddability Evaluation substrate A is observed with a microscopic microscope ("VH-5500" manufactured by Keyence Corporation) on the surface of the thermosetting resin composition layer, and there is no void and it is embedded in the wiring pattern. Those with voids were marked with “○”, and those with voids were marked with “×”.

(2-3) Thermosetting of thermosetting resin composition layer After lamination of the adhesive sheet, at 100 ° C. for 30 minutes, then at 170 ° C. (Example 1 and Comparative Example 1 support: release PET: 38 μm 170 ° C. in the state) or 180 ° C. (in Example 2 and Comparative Example 2, 180 ° C. in the state where the release PET was peeled) for 30 minutes. An insulating layer was formed on both sides of the layer.

(3) Step of forming a via hole in the insulating layer Example 1 and Comparative Example 1 from above the release PET or carrier copper foil, Example 2, Example 3, and Comparative Example 2 from above the insulating layer, A via hole was formed in the insulating layer immediately above the wiring layer having a size of 150 μm square to serve as a land of the wiring layer by irradiating the laser under the following conditions.

The via hole forming process was performed under different conditions as shown below.

(A) Using a CO ₂ laser processing machine "605GTWIII (-P)" manufactured by Mitsubishi Electric Corporation, a laser is irradiated from above the release PET side, and a via hole with a top diameter (diameter) of 30 μm is formed in the insulating layer. formed. The laser irradiation conditions were a mask diameter of 1 mm, a pulse width of 16 μs, an energy of 0.20 mJ/shot, two shots, and burst mode (10 kHz).
(B) Using a CO ₂ laser processing machine "LC-2k212/2C" manufactured by Via Mechanics Co., Ltd., a laser is irradiated from above the insulating layer to form a via hole with a top diameter (diameter) of 50 μm in the insulating layer. did. The laser irradiation conditions were a mask diameter of 3 mm, a pulse width of 4 μs, a power of 0.8 W, a shot number of 3, and a cycle mode (2 kHz).
(C) Using a CO ₂ laser processing machine “605GTWIII (-P)” manufactured by Mitsubishi Electric Corporation, a laser is irradiated from above a copper foil with a thickness of 3 μm after peeling off the carrier copper foil, and insulation A via hole with a top diameter (diameter) of 45 μm was formed in the layer. The laser irradiation conditions were a mask diameter of 1.5 mm, a pulse width of 16 μs, an energy of 0.36 mJ/shot, the number of shots being 3, and burst mode (10 kHz).

(3-1) Roughening Treatment After forming the via holes, if the release PET was bonded, it was peeled off, and the structure provided with the via holes was desmeared. As the desmear treatment, the following wet desmear treatment was performed.

Wet desmear treatment:
A circuit board provided with via holes is soaked in a swelling liquid ("Swelling Dip Securigant P" manufactured by Atotech Japan Co., Ltd., an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 3 minutes, and then in an oxidizing agent solution ( "Concentrate Compact CP" manufactured by Atotech Japan Co., Ltd., an aqueous solution with a potassium permanganate concentration of about 6% and sodium hydroxide concentration of about 4%) at 80 ° C. for 8 minutes, and finally a neutralizing solution (Atotech Japan Co., Ltd. ) manufactured by "Reduction Solution Securigant P", sulfuric acid aqueous solution) at 40°C for 5 minutes, and then dried at 80°C for 15 minutes.

(4) Process of forming a conductor layer (4-1) Electroless plating process In order to form a conductor layer on the surface of the evaluation substrate, a plating process including the following steps 1 to 6 (chemicals manufactured by Atotech Japan Co., Ltd. The copper plating process used) was performed to form a conductor layer.

1. Alkali cleaning (cleaning and charge adjustment of the surface of the insulating layer with via holes)
Trade name: Cleaning Cleaner Security 902 (trade name) was used to wash at 60° C. for 5 minutes.
2. Soft etching (cleaning inside via holes)
It was treated at 30° C. for 1 minute with a sulfuric acid-acid sodium peroxodisulfate aqueous solution.
3. Pre-dip (adjustment of surface charge of insulating layer for Pd application)
Pre. Dip Neoganth B (trade name) was used for 1 minute at room temperature.
4. Application of activator (application of Pd to the surface of the insulating layer)
Using Activator Neoganth 834 (trade name), it was treated at 35° C. for 5 minutes.
5. Reduction (reduction of Pd applied to the insulating layer)
Reducer Neoganth WA (trade name) and Reducer Accelerator 810 mod. (trade name) and treated at 30° C. for 5 minutes.
6. Electroless copper plating process (Cu is deposited on the surface of the insulating layer (Pd surface))
Using a mixed solution of Basic Solution Printganth MSK-DK (trade name), Copper solution Printganth MSK (trade name), Stabilizer Printganth MSK-DK (trade name), and Reducer Cu (trade name), at 35 ° C. Treated for 20 minutes. The thickness of the formed electroless copper plating layer was 0.8 μm.

(4-2) Electrolytic Plating Step Next, an electrolytic copper plating step was performed using a chemical solution manufactured by Atotech Japan Co., Ltd. under the condition that the via holes were filled with copper. After that, as a resist pattern for patterning by etching, a land pattern with a diameter of 100 μm corresponding to the via hole is formed (a portion without via connection is also formed on the entire surface at a pitch of 400 μm), and this land pattern is used to form the surface of the insulating layer. A conductor layer having a conductor pattern with a thickness of 10 μm was formed on the substrate. Annealing was then performed at 190° C. for 60 minutes.

(5) Step of removing the base material After pasting a PET film with adhesive (50 μm thick) on the entire surface of the base material with the wiring layer on which the conductor layer is formed, the MicroSyn MT-Ex copper foil of the core substrate is removed. The core substrate was separated by peeling at the interface between the 3 μm thick copper foil and the 18 μm thick carrier foil. Next, while the surface on which the conductor layer was formed was protected with an adhesive PET film, the 3 μm copper foil was removed by etching with an aqueous solution of copper chloride, washed with water, and dried at 110° C. for 30 minutes. After that, the PET film with the adhesive was peeled off, and a wiring board in which the L/S=10/10 μm comb tooth pattern was embedded on one side was produced. The obtained wiring board is called "evaluation board B".

<Bending test (crack)>
The evaluation board B was cut into a test piece having a width of 15 mm and a length of 110 mm, and was subjected to a load of 2 using an MIT testing device (MIT folding endurance fatigue tester "MIT-DA" manufactured by Toyo Seiki Seisakusho Co., Ltd.). The central part of the comb tooth pattern was bent 20 times in the vertical direction under the measurement conditions of 5 N, bending angle of 90 degrees, bending radius of 1.0 mm, and bending speed of 175 times/min. Observation was made with Keyence "VH-5500"). If there were no abnormalities such as cracks on both sides, it was rated as "○", and if there were cracks, it was rated as "x".

<Bending test (resistance value change)>
Further, the insulation resistance value (Ω) was measured with an electrochemical migration tester (manufactured by J-RAS Co., Ltd., "ECM-100 ”). The insulation resistance value (Ω) was evaluated according to the following evaluation criteria.
Evaluation criteria:
○: Change in resistance value after bending is 50% or less ×: Change in resistance value after bending exceeds 50%

<Evaluation of reflow warpage behavior>
After cutting the evaluation board B into five pieces of 30 mm square, it was passed once through a reflow device (“HAS-6116” manufactured by Nippon Antom Co., Ltd.) that reproduces a solder reflow temperature with a peak temperature of 260 ° C. (reflow temperature The profile conforms to IPC/JEDEC J-STD-020C). Then, using a shadow moire device (“TherMoire AXP” manufactured by Akrometrix), the lower surface of the evaluation substrate B is heated with a reflow temperature profile conforming to IPC/JEDEC J-STD-020C (peak temperature 260 ° C.), and the center of the substrate The displacement of a 5 mm square portion of was measured. Five individual pieces were tested, the average value was obtained, and evaluation was performed according to the following evaluation criteria.
Evaluation criteria:
○: Displacement amount is 50 μm or less ×: Displacement amount exceeds 50 μm

<Measurement of minimum melt viscosity of thermosetting resin composition layer>
Pellets for measurement (diameter 18 mm, 1.2 to 1.3 g) were prepared by peeling off only the thermosetting resin composition layer of each example and each comparative example and compressing them with a mold.

Using pellets for measurement, using a dynamic viscoelasticity measuring device (“Rheosol-G3000” manufactured by UBM Co., Ltd.), a parallel plate with a diameter of 18 mm is used for 1 g of a sample thermosetting resin composition layer. Then, the temperature was raised from the starting temperature of 60 ° C. to 200 ° C. at a heating rate of 5 ° C./min, and the dynamic viscoelastic modulus was measured under the measurement conditions of a measurement temperature interval of 2.5 ° C., a frequency of 1 Hz, and a strain of 1 deg. and the lowest melt viscosity (poise) was calculated.

<Measurement of breaking elongation>
An adhesive sheet having only a 30 μm-thick thermosetting resin composition layer prepared in Adhesive Sheets 1 to 3 was heated at 190° C. for 90 minutes to thermally cure the thermosetting resin composition layer, and then the release PET. A film (“PET501010” (thickness: 50 μm) manufactured by Lintec Corporation) was peeled off. The resulting cured product (thickness of 30 μm) was cut into a dumbbell shape, and the tensile strength of the test piece was measured using a tensile tester RTC-1250A manufactured by Orientec Co., Ltd. in accordance with JIS K 7127, at 23 ° C. The elongation at break was determined. This operation was performed 5 times, and the average value of the top three points was calculated.

<Preparation of Adhesive Sheet 1 Used in Example 1>
(1) Preparation of resin varnish 1 Bisphenol type epoxy resin ("ZX1059" manufactured by Nippon Steel Chemical Co., Ltd., 1:1 mixture of bisphenol A type and bisphenol F type, epoxy equivalent 169) 9 parts, crystalline bifunctional Epoxy resin (Mitsubishi Chemical Co., Ltd. "YX4000HK", epoxy equivalent about 185) 6 parts, biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000H", epoxy equivalent 288) 15 parts, phenoxy resin (Mitsubishi Chemical ( 15 parts of "YX6954BH30" manufactured by Kabushiki Kaisha, a 1:1 solution of MEK (methyl ethyl ketone) and cyclohexanone with a solid content of 30% by mass) were dissolved in 10 parts of solvent naphtha by heating with stirring. The heated and dissolved material is cooled to room temperature, and 10 parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation "LA-7054", a 60% solid content MEK solution with a hydroxyl equivalent of 125), naphthalene type curing. Agent ("SN-485" manufactured by Nippon Steel Chemical Co., Ltd. MEK solution with a solid content of 60% with a hydroxyl equivalent of 215) 10 parts, polyvinyl acetal resin (manufactured by Sekisui Chemical Co., Ltd. "BX-5Z", solid content 15 1:1 solution of ethanol and toluene (% by mass)) 15 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass) 0.2 parts, imidazole curing accelerator (Mitsubishi Chemical Co., Ltd. "P200-H50", propylene glycol monomethyl ether solution with a solid content of 50% by mass) 0.1 part, flame retardant (Sanko Co., Ltd. "HCA-HQ", 10-(2,5-dihydroxyphenyl )-10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm) 3 parts, and a phenylaminosilane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" ) surface-treated spherical silica (average particle size 0.5 μm, “SOC2” manufactured by Admatechs Co., Ltd., carbon amount per unit area 0.39 mg/m ² ) 40 parts, and mixed with a high-speed rotating mixer. The mixture was uniformly dispersed and filtered through a cartridge filter ("SHP050" manufactured by ROKITECHNO) to prepare resin varnish 1.

(2) Preparation of resin varnish 2 Bisphenol type epoxy resin ("ZX1059" manufactured by Nippon Steel Chemical Co., Ltd., 1:1 mixture of bisphenol A type and bisphenol F type, epoxy equivalent 169) 9 parts, crystalline bifunctional Epoxy resin (Mitsubishi Chemical Co., Ltd. "YX4000HK", epoxy equivalent about 185) 6 parts, biphenyl type epoxy resin (Nippon Kayaku Co., Ltd. "NC3000H", epoxy equivalent 288) 15 parts, phenoxy resin (Mitsubishi Chemical ( 15 parts of "YX6954BH30" manufactured by Kabushiki Kaisha, a 1:1 solution of MEK (methyl ethyl ketone) and cyclohexanone with a solid content of 30% by mass) were dissolved in 10 parts of solvent naphtha by heating with stirring. The heated and dissolved material is cooled to room temperature, and 10 parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation "LA-7054", a 60% solid content MEK solution with a hydroxyl equivalent of 125), naphthalene type curing. agent ("SN-485" manufactured by Nippon Steel Chemical Co., Ltd. MEK solution with a solid content of 60% with a hydroxyl equivalent of 215) 10 parts, polyvinyl acetal resin (manufactured by Sekisui Chemical Co., Ltd. "KS-1", solid content 15 1:1 solution of ethanol and toluene (% by mass)) 15 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass) 0.4 parts, imidazole curing accelerator (Mitsubishi Chemical "P200-H50" manufactured by Co., Ltd., propylene glycol monomethyl ether solution with a solid content of 50% by mass) 0.4 parts of rubber particles (manufactured by Ganz Kasei Co., Ltd., AC3816N) are added to 8 parts of solvent naphtha at 12 parts at room temperature. Swelled for a long time, and spherical silica surface-treated with a phenylaminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) (average particle size 0.24 μm, manufactured by Admatechs Co., Ltd.) 30 parts of "SOC1" (carbon content per unit area: 0.36 mg/m ² ) were mixed, uniformly dispersed with a high-speed rotating mixer, filtered through a cartridge filter ("SHP030" manufactured by ROKITECHNO), and a resin varnish was obtained. 2 was produced.

(3) Preparation of adhesive sheet 1 On the release surface of a polyethylene terephthalate film with release treatment (hereinafter abbreviated as release PET) ("AL5" manufactured by Lintec Co., Ltd., thickness 25 µm), a thermosetting adhesive after drying is placed on the release surface. The resin varnish 1 was uniformly applied so that the thickness of the thermosetting resin composition layer 1 was 10 μm, and dried at 80 to 120° C. (average 100° C.) for 2.5 minutes to form the thermosetting resin composition layer 1. After that, a polyimide film (“Kapton 20EN” manufactured by Toray DuPont Co., Ltd., thickness 5 μm, with plasma treatment on both sides) is laminated with a hot roll so as to be bonded to the thermosetting resin composition layer 1, and an adhesive sheet (1 -1) was produced.

On the other hand, the resin varnish 2 is uniformly applied on the release surface of the release PET (“AL5” manufactured by Lintec Corporation, thickness 38 μm) so that the thickness of the thermosetting resin composition layer 2 after drying is 3 μm. and dried at 80 to 120 ° C. (average 100 ° C.) for 2 minutes to form the thermosetting resin composition layer 2, and then the polyimide film surface of the adhesive sheet (1-1) is coated with the thermosetting resin composition layer. 2, release PET (25 μm) / thermosetting resin composition layer 1 (10 μm) / polyimide film (5 μm) / thermosetting resin composition layer 2 (3 μm) / release An adhesive sheet 1 having a configuration of type PET (38 μm) was obtained.

<Production of Adhesive Sheet 2 Used in Example 2>
(1) Preparation of resin varnish 3 50 parts of polymer resin A prepared as follows, bisphenol type epoxy resin (“ZX1059” manufactured by Nippon Steel Chemical Co., Ltd., 1:1 mixture of bisphenol A type and bisphenol F type product, epoxy equivalent 169) 3 parts, crystalline bifunctional epoxy resin (manufactured by Mitsubishi Chemical Corporation "YX4000HK", epoxy equivalent about 185) 3 parts, naphthalene type epoxy resin (manufactured by DIC Corporation "HP4032SS", epoxy equivalent 3 parts of about 144) was heated and dissolved in 25 parts of solvent naphtha with stirring. The heated and dissolved material is cooled to room temperature, and an active ester compound (“HPC8000-65T” manufactured by DIC Corporation, a weight average molecular weight of about 2700, an active group equivalent of about 223, a nonvolatile content of 65% by mass, and a toluene solution ) 4 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass) 0.4 parts, imidazole curing accelerator (manufactured by Mitsubishi Chemical Corporation "P200-H50", solid 0.3 part of a propylene glycol monomethyl ether solution (50% by weight), and spherical silica surface-treated with a phenylaminosilane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573") (average particle size: 0.3 parts). 5 μm, “SOC2” manufactured by Admatechs Co., Ltd., carbon content per unit area of 0.39 mg/m ² ) 60 parts were mixed, uniformly dispersed with a high-speed rotating mixer, and filtered through a cartridge filter (“SHP050” manufactured by ROKITECHNO). ) to prepare a resin varnish 3.

-Preparation of polymer resin A-
G-3000 (bifunctional hydroxyl group-terminated polybutadiene, number average molecular weight = 5047 (number average molecular weight in terms of polystyrene by GPC method), hydroxyl group equivalent: 1798 g / eq., solid content 100% by mass: Nippon Soda ( Co., Ltd.), 23.5 g of Ipsol 150 (aromatic hydrocarbon-based mixed solvent: manufactured by Idemitsu Petrochemical Co., Ltd.), and 0.005 g of dibutyltin laurate were mixed and uniformly dissolved. When the mixture became homogeneous, the temperature was raised to 50° C., and 4.8 g of toluene-2,4-diisocyanate (isocyanate group equivalent: 87.08 g/eq.) was added with further stirring, and the reaction was carried out for about 3 hours. The reaction was then allowed to cool to room temperature before adding 8.96 g of benzophenonetetracarboxylic dianhydride (anhydride equivalent: 161.1 g/eq.), 0.07 g of triethylenediamine, and ethyl diglycol. 40.4 g of acetate (manufactured by Daicel Chemical Industries, Ltd.) was added, the temperature was raised to 130° C. with stirring, and the reaction was carried out for about 4 hours. The disappearance of the NCO peak at 2250 cm ⁻¹ was confirmed by FT-IR. Confirmation of the disappearance of the NCO peak was regarded as the end point of the reaction, and the reactant was cooled to room temperature and filtered through a 100-mesh filter cloth to obtain polymer resin A having an imide skeleton, a urethane skeleton, and a butadiene skeleton.
Viscosity: 7.5 Pa s (25°C, E-type viscometer)
Acid value: 16.9mgKOH/g
Solid content: 50% by mass
Number average molecular weight: 13723 (converted to polystyrene by GPC method)
Glass transition temperature: -10°C (measured by DSC method)
Content of polybutadiene structural portion: 50/(50+4.8+8.96)×100=78.4% by mass.

(2) Preparation of adhesive sheet 2 A polyimide film (“Apical 10NPI” manufactured by Kaneka Co., Ltd., 10 μm thick, with corona treatment on both sides) is immersed in the resin varnish 3, and the thickness of the thermosetting resin composition layer after drying. is squeezed to 10 μm on both sides, and dried at 80 to 120° C. (average 100° C.) for 3 minutes to form a thermosetting resin composition layer 3. Release PET (Lintec Co., Ltd.) is applied to one resin surface. ) made "AL5", thickness 38 μm) and a protective film (polypropylene film, Oji F-Tex Co., Ltd. "Alphan MA-430", thickness 20 μm) on the other side with a hot roll, An adhesive sheet 2 having a configuration of release PET (38 μm) / thermosetting resin composition layer 3 (10 μm) / polyimide film (10 μm) / thermosetting resin composition layer 3 (10 μm) / protective film (20 μm) Obtained.

<Production of Adhesive Sheet 3 Used in Example 3>
Two-layer single-sided copper-clad polyimide film (manufactured by Arisawa Seisakusho Co., Ltd., Mitsui Kinzoku Mining Co., Ltd. Microshin MT-Ex (18 μm carrier copper foil / 3 μm thick copper foil) on the upper surface of a 3 μm thick copper foil , a polyimide film having a thickness of 12.5 μm) is coated uniformly with a resin varnish 3 so that the thickness of the thermosetting resin composition layer 3 after drying is 10 μm. After drying for 2.5 minutes at 120 ° C. (average 100 ° C.) to form the thermosetting resin composition layer 3, a protective film (polypropylene film, Oji F-Tex Co., Ltd. “Alphan MA-430”, thickness 20 μm) is bonded to the thermosetting resin composition layer 3, copper foil (18 μm carrier foil / 3 μm copper foil) / polyimide film (12.5 μm) / thermosetting resin composition layer 3 (10 μm )/protective film (20 μm).

<Preparation of Adhesive Sheet 4 Used in Comparative Example 1>
A resin varnish 1 is evenly applied to the release surface of release PET (“AL5” manufactured by Lintec Corporation, thickness 38 μm) so that the thickness of the thermosetting resin composition layer 1 after drying is 18 μm. Then, after forming the thermosetting resin composition layer 1 by drying at 80 to 120 ° C. (average 100 ° C.) for 3 minutes, a protective film (polypropylene film, Oji F-Tex Co., Ltd. "Alphan MA-430", thickness 20 μm) is bonded to the thermosetting resin composition layer 1, and adhesion having a configuration of release PET (38 μm) / thermosetting resin composition layer 1 (18 μm) / protective film (20 μm) Sheet 4 was obtained.

<Production of Adhesive Sheet 5 Used in Comparative Example 2>
A resin varnish 3 is evenly applied to the release surface of release PET (“AL5” manufactured by Lintec Corporation, thickness 38 μm) so that the thickness of the thermosetting resin composition layer 3 after drying is 30 μm. Then, after drying at 80 to 120 ° C. (average 100 ° C.) for 4 minutes to form a thermosetting resin composition layer 3, a protective film (polypropylene film, Oji F-Tex Co., Ltd. "Alphan MA-430", thickness 20 μm) is bonded to the thermosetting resin composition layer 3, and adhesion having a configuration of release PET (38 μm) / thermosetting resin composition layer 3 (30 μm) / protective film (20 μm) Sheet 5 was obtained.

１）：二層片面銅張りポリイミドフィルムのうち、銅箔部分を（ｉｉｉ）の層とし（厚みは合計値）、ポリイミドフィルム部分を樹脂フィルム層（（ｉｉ）の層）とした。

1): Of the two-layer single-sided copper-clad polyimide film, the copper foil portion was used as the layer (iii) (thickness is the total value), and the polyimide film portion was used as the resin film layer (layer (ii)).

10 base material with wiring layer 11 base material (core substrate)
12 First metal layer 13 Second metal layer 14 Wiring layer (embedded wiring layer)
20 Adhesive sheet 21 (i) Thermosetting resin composition layer (insulating layer)
22 (ii) resin film layer 23 (iii) thermosetting resin composition layer (insulating layer)
24 protective film 25 (iii) metal foil 31 via hole 40 conductor layer 41 plating seed layer 42 electroplating layer 43 conductor layer 50 mask pattern 61 filled via

Claims (5)

comprising a resin film layer, an insulating layer, and an embedded wiring layer embedded in the insulating layer,
The insulating layer comprises (a) an epoxy resin, (b) one or more curing agents selected from phenolic curing agents, naphthol curing agents, active ester curing agents and cyanate ester curing agents, and (c) inorganic obtained by curing a resin composition layer containing a filler,
The resin film layer contains polyimide, polyethylene terephthalate, polyethylene naphthalate, liquid crystal polymer, polyphenylene sulfide, polyetheretherketone, polybenzimidazole, aramid, polyamideimide, or polyetherimide,
The change in the resistance value after the bending test at a bending angle of 90 degrees from before the bending test is 50% or less,
The resin film layer and the resin composition layer are obtained by heating an adhesive sheet containing a resin film layer and a resin composition layer having a thickness of 30 μm at 190° C. for 90 minutes and measuring the cured product in accordance with JIS K 7127 at 23° C. Breaking elongation is 3% or more and 10% or less ,
wiring board. The wiring board according to claim 1, which is a flexible wiring board. 3. The wiring board according to claim 1, wherein the insulating layer has a thickness of 2 [mu]m or more. The wiring board according to any one of claims 1 to 3, wherein the resin film layer has a thickness of 2 µm or more. A semiconductor device comprising the wiring board according to any one of claims 1 to 4.

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