JP6969099B2 - Resin sheet manufacturing method - Google Patents

Description

The present invention relates to a method for producing a resin sheet. Further, the present invention relates to a resin sheet, a method for manufacturing a printed wiring board, a printed wiring board, and a semiconductor device.

As a manufacturing technique for printed wiring boards, a build-up method in which circuit-formed conductor layers and insulating layers are alternately stacked is widely used. In the build-up method, the insulating layer is generally formed by laminating a resin sheet containing a resin composition layer on an inner layer substrate and curing the resin composition layer.

In recent years, it has been known that the content of the inorganic filler in the resin composition layer is increased to reduce the coefficient of thermal expansion of the insulating layer, but when the content of the inorganic filler is large, the obtained insulating layer is obtained. And the adhesion strength (peel strength) between the conductor layer and the conductor layer tends to decrease. Therefore, for example, Patent Document 1 discloses a resin sheet containing a plurality of resin composition layers and including a layer having a large proportion of resin components as the resin composition layer to be bonded to the conductor layer. Has been done.

Japanese Unexamined Patent Publication No. 2014-17301

In the case of an insulating layer formed by using a resin sheet containing a plurality of resin composition layers, delamination occurs when the insulating layer is exposed to a high temperature environment such as during reflow. I found that there is. The present inventors also found that in a resin sheet containing a plurality of resin composition layers, it is difficult to control the thickness of each layer, which may result in an insulating layer having poor roughness and peel strength stability. I found it.

An object of the present invention is to provide a method for producing a resin sheet capable of suppressing delamination and realizing an insulating layer having high stability of roughness and peel strength.

As a result of diligent studies on the above problems, the present inventors have mixed the components of each resin composition layer in the region where the resin composition layers are in contact with each other when producing a resin sheet containing a plurality of resin composition layers. We have found that the above-mentioned problems can be solved by newly providing a layer to be formed, and have completed the present invention.

That is, the present invention includes the following contents.
[1] From a first resin composition layer composed of a support, a first resin composition provided on the support, and a second resin composition provided on the first resin composition layer. It has a second resin composition layer, and the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. It is a method for manufacturing a resin sheet having a mixed layer.
A first resin varnish in which the first resin composition is dissolved is applied onto the support, and a second resin varnish in which the second resin composition is dissolved is applied onto the first resin varnish and dried. Including the process of
The viscosity of the first resin varnish is 100 mPa · s or more,
A method for producing a resin sheet, wherein the viscosity of the second resin varnish is 100 mPa · s or more.
[2] The step of applying the first resin varnish on the support and at the same time applying the second resin varnish on the first resin varnish and then drying is included, or
The resin according to [1], which comprises a step of applying a first resin varnish on a support, pre-drying it, then applying a second resin varnish on the first resin varnish, and then drying it. How to make a sheet.
[3] The amount of residual solvent in the first resin varnish after pre-drying is 15% by mass to 70% by mass when the total of the non-volatile components contained in the first resin varnish is 100% by mass. A method for manufacturing a resin sheet according to [2].
[4] The method according to [1] or [2], which comprises a step of applying the first resin varnish on the support and at the same time applying the second resin varnish on the first resin varnish and then drying. How to manufacture a resin sheet.
[5] The first resin composition layer has a thickness of 0.3 μm to 15 μm, a second resin composition layer has a thickness of 3 μm to 200 μm, and a mixed layer has a thickness of 0.4 μm or more. The method for producing a resin sheet according to any one of [1] to [4], which is not more than twice the thickness of the resin composition layer.
[6] The method for producing a resin sheet according to any one of [1] to [5], wherein the support is a support with a release layer.
[7] The method according to any one of [1] to [6], wherein the minimum melt viscosity of the first resin composition layer is 3000 poise or more, and the minimum melt viscosity of the second resin composition layer is 10,000 poise or less. How to manufacture a resin sheet.
[8] The viscosity of the first resin varnish is 100 mPa · s to 3000 mPa · s, and the viscosity of the second resin varnish is 100 mPa · s to 6000 mPa · s, according to any one of [1] to [7]. The method for manufacturing a resin sheet according to the description.
[9] The method for producing a resin sheet according to any one of [1] to [8], wherein the first resin varnish and the second resin varnish are applied on the same coating line.
[10] A method for manufacturing a printed wiring board, wherein a resin sheet manufactured by the method according to any one of [1] to [9] is laminated on an inner layer substrate, heat-cured, and then the support is removed.
[11] From a first resin composition layer composed of a support, a first resin composition provided on the support, and a second resin composition provided on the first resin composition layer. It has a second resin composition layer, and the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. A resin sheet having a mixed layer having a thickness of 0.4 μm or more.
[12] The first resin composition layer has a thickness of 0.3 μm to 15 μm, a second resin composition layer has a thickness of 3 μm to 200 μm, and a mixed layer has a thickness of 0.4 μm or more. The resin sheet according to [11], which is not more than twice the thickness of the resin composition layer.
[13] The resin sheet according to [11] or [12], wherein the minimum melt viscosity of the first resin composition layer is 3000 poise or more.
[14] The resin sheet according to any one of [11] to [13], wherein the minimum melt viscosity of the second resin composition layer is 10,000 poise or less.
[15] A printed wiring board including an insulating layer formed by using the resin sheet according to any one of [11] to [14].
[16] A semiconductor device including the printed wiring board according to [15].

According to the present invention, it has become possible to provide a method for producing a resin sheet capable of suppressing delamination and realizing an insulating layer having high stability of roughness and peel strength.

FIG. 1 is a schematic cross-sectional view showing an example of the resin sheet of the present invention. FIG. 2 is a schematic view showing an example of the method for producing a resin sheet of the present invention. FIG. 3 is a schematic view showing another example of the method for producing a resin sheet of the present invention.

Hereinafter, the present invention will be described in detail.
[Resin sheet]
The resin sheet of the present invention has a first resin composition layer composed of a support, a first resin composition provided on the support, and a second resin composition layer provided on the first resin composition layer. It has a second resin composition layer made of a resin composition, and a first resin composition and a second resin composition are placed between the first resin composition layer and the second resin composition layer. It is characterized in that it has a mixed layer in which is mixed, and the thickness of the mixed layer is 0.4 μm or more.

As described above, in an insulating layer formed by using a resin sheet containing a plurality of resin composition layers, delamination may occur when exposed to a high temperature environment such as during reflow. The present inventors have found that. When an insulating layer is formed using a resin sheet containing a plurality of resin composition layers, a plurality of cured product layers derived from each resin composition layer are formed in the obtained insulating layer. Due to the difference in composition, these cured product layers may exhibit different expansion rates in a high temperature environment. In such a case, since stress is concentrated between the layers, it is presumed that delamination is likely to occur. In this respect, the resin sheet of the present invention has a mixed layer in which each resin composition forming the first and second resin composition layers is mixed between the first and second resin composition layers. In the insulating layer formed by using the resin sheet of the present invention, a first cured product layer derived from the first resin composition layer and a second cured product derived from the second resin composition layer are used. A cured product layer derived from the mixed layer is formed between the layers. The cured product layer derived from the mixed layer relaxes the concentration of stress due to the difference in expansion coefficient between the first cured product layer and the second cured product layer, and thus delaminates in a high temperature environment such as during reflow. It is possible to suppress. Even when the insulating layer is formed by using a conventional resin sheet containing a plurality of resin composition layers, a stress relaxation layer may be formed depending on the composition of each resin composition layer and the thermosetting conditions. .. However, the thickness of the stress relaxation layer formed was not sufficient to solve the problem of delamination in a high temperature environment. On the other hand, by using the resin sheet of the present invention having a mixed layer having a predetermined thickness, an insulating layer in which delamination is suppressed can be easily formed regardless of the composition of each resin composition layer and the thermosetting conditions. It is feasible.

FIG. 1 is a schematic cross-sectional view showing an example of the resin sheet of the present invention. In the resin sheet 1 shown in FIG. 1, the support 11, the first resin composition layer 12, the mixed layer 13, and the second resin composition layer 14 are laminated in this order.
Hereinafter, each layer constituting the resin sheet of the present invention will be described in detail.

<Support>
The resin sheet of the present invention has a support. Examples of the support in the present invention include a film made of a plastic material, a metal foil, and a paper pattern, and a film made of a plastic material and a metal foil are preferable.

When a film made of a plastic material is used as the support, the plastic material may be, for example, polyethylene terephthalate (hereinafter abbreviated as "PET") or polyethylene naphthalate (hereinafter abbreviated as "PEN"). ) And other polyesters, polycarbonate (hereinafter sometimes abbreviated as "PC"), acrylics such as polymethylmethacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyethersulfide (PES), polyethers. Examples include ketones and polyimides. Of these, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable.

When a metal foil is used as the support, examples of the metal foil include copper foil, aluminum foil, and the like, and copper foil is preferable. 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 another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used. You may use it.

The support may be matted or corona-treated on the surface to be joined to the first resin composition layer.

Further, as the support, a support with a release layer having a release layer on the surface to be joined to the first resin composition layer may be used. Examples of the release agent used for the release layer of the support with the release layer include one or more release agents selected from the group consisting of alkyd resin, polyolefin resin, urethane resin, and silicone resin. .. As the support with a release layer, a commercially available product may be used. For example, "SK-1" manufactured by Lintec Co., Ltd., which is a PET film having a release layer containing an alkyd resin-based mold release agent as a main component. , "AL-5", "AL-7", "Lumirror T6AM" manufactured by Toray Industries, Inc., and the like.

The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably in the above range.

<First resin composition layer>
The resin sheet of the present invention has a first resin composition layer made of the first resin composition. The first resin composition layer is bonded to the support, and when the printed wiring board is manufactured, a region near the surface of the insulating layer on which the conductor layer is provided is formed. The first resin composition is not particularly limited as long as the cured product has sufficient hardness and insulating properties. Examples of such a resin composition include a composition containing a curable resin and a curing agent thereof. As the curable resin, a conventionally known curable resin used for forming an insulating layer of a printed wiring board can be used, and an epoxy resin is particularly preferable. Therefore, in one embodiment, the first resin composition comprises (a) an epoxy resin and (b) a curing agent. The first resin composition further contains (c) an inorganic filler, (d) a thermoplastic resin, (e) a curing accelerator, (f) a flame retardant, (g) an organic filler and the like, if necessary. It may contain an agent.

Hereinafter, the epoxy resin, the curing agent, and the additive that can be used as the material of the first resin composition will be described.

-(A) Epoxy resin-
Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol type epoxy resin, and 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 novolac type epoxy resin, biphenyl type Epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin and tori Examples thereof include a methylol type epoxy resin. The epoxy resin may be used alone or in combination of two or more.

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% by mass, at least 50% by mass or more is preferably an epoxy resin having two or more epoxy groups in one molecule. Above all, it is preferable to contain two or more (preferably three or more) epoxy groups in one molecule and a solid epoxy resin (hereinafter referred to as "solid epoxy resin") at a temperature of 20 ° C. The epoxy resin may also contain an epoxy resin having two or more epoxy groups in one molecule and liquid at a temperature of 20 ° C. (hereinafter referred to as “liquid epoxy resin”). In the first resin composition, the content of the solid epoxy resin in the epoxy resin is preferably 30% by mass or more, more preferably 40% by mass or more, when the non-volatile component of the entire epoxy resin is 100% by mass. More preferably, it is 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. The upper limit of the content of the solid epoxy resin is not particularly limited and may be 100% by mass.

Examples of the liquid epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, alicyclic epoxy resin having an ester skeleton, and cyclohexanedimethanol type. Epoxy resin, glycidylamine type epoxy resin, epoxy resin having a butadiene structure, phenol novolac type epoxy resin, and naphthalene type epoxy resin are preferable, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, and naphthalene. Type epoxy resin is more preferable, and bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AF type epoxy resin are further preferable. Specific examples of the liquid epoxy resin include "HP4032", "HP4032D", "HP4032SS" (naphthalene type epoxy resin) manufactured by DIC Co., Ltd., and "jER828EL" (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation. , "JER807" (bisphenol F type epoxy resin), "YL7223", "YL7723" (bisphenol AF type epoxy resin), "jER152" (phenol novolak type epoxy resin), "ZX1059" manufactured by Nippon Steel & Sumitomo Metal Corporation (ZX1059) Examples thereof include "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Corporation (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin). These may be used alone or in combination of two or more.

Examples of the solid epoxy resin 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, naphthol novolac type epoxy resin, and biphenyl. Type epoxy resin, naphthylene ether type epoxy resin, anthracene type epoxy resin, bisphenol A type epoxy resin, and tetraphenylethane type epoxy resin are preferable, and naphthalene type tetrafunctional epoxy resin, biphenyl type epoxy resin, or naphthylene ether type epoxy. The resin is more preferable, and the naphthalene type tetrafunctional epoxy resin and the biphenyl type epoxy resin are further preferable. Specific examples of the solid epoxy resin include "HP-4700", "HP-4710" (naphthalen type tetrafunctional epoxy resin), "N-690" (cresol novolac type epoxy resin), and "Cresor novolac type epoxy resin" manufactured by DIC Co., Ltd. N-695 "(cresol novolac type epoxy resin)," HP-7200 "(dicyclopentadiene type epoxy resin)," EXA7311 "," EXA7311-G3 "," EXA7311-G4 "," EXA7311-G4S "," HP6000 (Naftylene ether type epoxy resin), "EPPN-502H" (trisphenol epoxy resin), "NC7000L" (naphthol novolac epoxy resin), "NC3000H", "NC3000", "NC3000L" manufactured by Nippon Kayaku Co., Ltd. , "NC3100" (biphenyl type epoxy resin), "ESN475V" (naphthol novolac type epoxy resin) manufactured by Nippon Steel & Sumitomo Metal Corporation, "ESN485V" (naphthol novolac type epoxy resin), "SNoftor novolac type epoxy resin" manufactured by Mitsubishi Chemical Co., Ltd. YX4000H "," YL6121 "(biphenyl type epoxy resin)," YX4000HK "(bixilenol type epoxy resin)," PG-100 "," CG-500 "manufactured by Osaka Gas Chemical Co., Ltd., manufactured by Mitsubishi Chemical Co., Ltd. "YL7800" (fluorene type epoxy resin), "YL7760" (bisphenol AF type epoxy resin) and the like can be mentioned.

The content of the epoxy resin in the first resin composition is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more or 30% by mass or more. The upper limit of the content of the epoxy resin is not particularly limited, but is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less.
In the present invention, the content of each component constituting the resin composition is a value when the total of the non-volatile components in the resin composition is 100% by mass, unless otherwise specified.

The epoxy equivalent of the epoxy resin is preferably 50 to 3000, more preferably 80 to 2000, and even more preferably 110 to 1000. Within this range, the crosslink density of the cured product becomes sufficient, and an insulating layer having a small surface roughness can be obtained. The epoxy equivalent can be measured according to JIS K7236, and is the mass of the resin containing 1 equivalent of the epoxy group.

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

-(B) Hardener-
The curing agent is not particularly limited as long as it has a function of curing the epoxy resin, and for example, a phenol-based curing agent, a naphthol-based curing agent, an active ester-based curing agent, a benzoxazine-based curing agent, a cyanate ester-based curing agent, and a curing agent. Examples include carbodiimide-based curing agents. The curing agent may be used alone or in combination of two or more.

As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a novolak structure or a naphthol-based curing agent having a novolak structure is preferable from the viewpoint of heat resistance and water resistance. Further, from the viewpoint of adhesion to the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based 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 (peeling strength) to the conductor layer.

Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., and Nippon Kayaku Co., Ltd. "NHN", "CBN", "GPH", Nippon Steel & Sumitomo Metal Corporation "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN375", "SN395" , "LA-7052", "LA-7054", "LA-3018", "EXB-9500" and the like manufactured by DIC Corporation.
Specific examples of the triazine skeleton-containing phenol novolac curing agent include "LA-3018-50P" and the like.

An active ester-based curing agent is also preferable from the viewpoint of obtaining an insulating layer having a small surface roughness after the roughening treatment. The active ester-based curing agent is not particularly limited, but generally contains one molecule of highly reactive ester group such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. A compound having two or more of them is preferably used. The active ester-based 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-based curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester-based curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid and the like. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, 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, dihydroxybenzophenol, trihydroxybenzophenone, tetrahydroxybenzophenone, fluoroglucin, Examples thereof include benzenetriol, dicyclopentadiene-type diphenol compound, and phenol novolac. Here, the "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two phenol molecules with one dicyclopentadiene molecule.

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 novolac are preferable. Of these, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadiene-type diphenol structure are more preferable. The "dicyclopentadiene-type diphenol structure" represents a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

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

Specific examples of the benzoxazine-based curing agent include "HFB2006M" manufactured by Showa High Polymer Co., Ltd., "P-d" and "FA" manufactured by Shikoku Chemicals Corporation.

Examples of the cyanate ester-based curing agent include bisphenol A dicyanate, polyphenol cyanate, oligo (3-methylene-1,5-phenylencyanate), 4,4'-methylenebis (2,6-dimethylphenylcyanate), and 4,4. '-Etilidene diphenyl disyanate, hexafluorobisphenol A dicyanate, 2,2-bis (4-cyanate) phenylpropane, 1,1-bis (4-cyanate phenylmethane), bis (4-cyanate-3,5-dimethyl) Bifunctional cyanate resins such as phenyl) methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bis (4-cyanatephenyl) ether, phenol. Examples thereof include polyfunctional cyanate resins derived from novolak and cresol novolak, and prepolymers in which these cyanate resins are partially triazined. Specific examples of the cyanate ester-based curing agent include "PT30" and "PT60" (both are phenol novolac type polyfunctional cyanate ester resins) and "BA230" (part or all of bisphenol A dicyanate) manufactured by Lonza Japan Co., Ltd. Is a prepolymer that has been triadinated into a trimer) and the like.

Specific examples of the carbodiimide-based curing agent include "V-03" and "V-07" manufactured by Nisshinbo Chemical Co., Ltd.

The amount ratio of the epoxy resin to the curing agent is a ratio of [total number of epoxy groups in the epoxy resin]: [total number of reactive groups in the curing agent], preferably in the range of 1: 0.2 to 1: 2. 1: 0.3 to 1: 1.5 is more preferable, and 1: 0.4 to 1: 1.2 is even more preferable. Here, the reactive group of the curing agent is an active hydroxyl group, an active ester group, or the like, and differs depending on the type of the curing agent. The total number of epoxy groups in the epoxy resin is the total number of all epoxy resins obtained by dividing the solid content mass of each epoxy resin by the epoxy equivalent, and the total number of reactive groups in the curing agent is The value obtained by dividing the solid content mass of each curing agent by the reaction group equivalent is the total value for all the curing agents. By setting the amount ratio of the epoxy resin and the curing agent within such a range, the heat resistance of the cured product of the resin composition is further improved.

In one embodiment, the first resin composition comprises the above-mentioned (a) epoxy resin and (b) curing agent. The first resin composition is (a) an epoxy resin containing a solid epoxy resin as an epoxy resin (the content of the solid epoxy resin in the epoxy resin is preferably 30% by mass or more, more preferably 40% by mass or more, More preferably, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more) is used as (b) a phenol-based curing agent, a naphthol-based curing agent, or an active ester-based curing agent. One or more selected from the group consisting of a curing agent and a cyanate ester-based curing agent (preferably one or more selected from the group consisting of a phenol-based curing agent, a naphthol-based curing agent and an active ester-based curing agent). It is preferable to include it.

The content of the curing agent in the first resin composition is not particularly limited, but is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less, still more preferably 15% by mass or less. Is. The lower limit is not particularly limited, but is preferably 3% by mass or more.

-(C) Inorganic filler-
The first resin composition may further contain an inorganic filler. The material of the inorganic filler is not particularly limited, but for example, silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, 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, zirconium tungstate phosphate and the like. Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica, and hollow silica are particularly suitable. Further, as silica, spherical silica is preferable. The inorganic filler may be used alone or in combination of two or more.

The average particle size of the inorganic filler used in the first resin composition is not particularly limited, but is preferably 600 nm or less, more preferably 300 nm or less, still more preferably 200 nm from the viewpoint of obtaining an insulating layer having a small surface roughness. Below, even more preferably, it is 150 nm or less, 100 nm or less, 90 nm or less, 80 nm or less, 70 nm or less, 60 nm or less, or 50 nm or less. The lower limit of the average particle size is not particularly limited, but is usually 5 nm or more. Examples of commercially available inorganic fillers having such an average particle size include "YC100C", "YA050C", "YA050C-MJE", "YA010C" manufactured by Admatex Co., Ltd., and "UFP-" manufactured by Denki Kagaku Kogyo Co., Ltd. 30 ”,“ Silfil NSS-3N ”,“ Silfil NSS-4N ”, and“ Silfil NSS-5N ”manufactured by Tokuyama.
The average particle size of the inorganic filler can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, it can be measured by creating a particle size distribution of the inorganic filler on a volume basis using a laser diffraction / scattering type particle size distribution measuring device and using the median diameter as the average particle size. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction / scattering type particle size distribution measuring device, "LA-500" manufactured by HORIBA, Ltd. or the like can be used.

From the viewpoint of enhancing moisture resistance and dispersibility, the inorganic filler is an aminosilane-based coupling agent, an epoxysilane-based coupling agent, a mercaptosilane-based coupling agent, a silane-based coupling agent, an organosilazane compound, and a titanate-based coupling agent. It is preferable that the treatment is performed with one or more surface treatment agents such as. Commercially available surface treatment agents include, for example, "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. and "KBM803" (3-mercaptopropyltrimethoxy) manufactured by Shin-Etsu Chemical Co., Ltd. Silane), "KBE903" (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., Shin-Etsu Chemical Co., Ltd. Examples thereof include "SZ-31" (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd. and "KBM103" (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

The degree of surface treatment with the surface treatment agent can be evaluated by the amount of carbon per unit surface area of the inorganic filler. Carbon content per unit surface area of the inorganic filler, from the viewpoint of improving dispersibility of the inorganic filler is preferably 0.02 mg / ^{m 2} or more, 0.1 mg / ^{m 2} or more preferably, 0.2 mg / ^{m 2} 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, 1 mg / m ² or less is preferable, 0.8 mg / m ² or less is more preferable, and 0.5 mg / m ² or less is further preferable. preferable.

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

The content of the inorganic filler in the first resin composition is not particularly limited, but is preferably 60% by mass or less, more preferably 55% by mass or less, still more preferably 50% by mass or less, still more preferably 48% by mass. Hereinafter, it is 46% by mass or less, 44% by mass or less, 42% by mass or less, or 40% by mass or less. The lower limit of the content of the inorganic filler in the first resin composition is not particularly limited and may be 0% by mass.

-(D) Thermoplastic resin-
The first resin composition may further contain a thermoplastic resin. Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, acrylic resin, polyolefin resin, polybutadiene resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polyetherimide resin, polycarbonate resin, polyetheretherketone resin, and the like. Examples thereof include polyester resin, polyphenylene ether resin and polysulfone resin. The thermoplastic resin may be used alone 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 LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device and Shodex K-800P / K- of Showa Denko Corporation as a column. 804L / K-804L can be measured using chloroform or the like as a mobile phase at a column temperature of 40 ° C. and calculated using a standard polystyrene calibration curve.

Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantan skeleton, and terpene. Examples thereof include phenoxy resins having one or more skeletons selected from the group consisting of skeletons and trimethylcyclohexane skeletons. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. The phenoxy resin may be used alone or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resin), "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" manufactured by Mitsubishi Chemical Corporation. Bisphenol acetophenone skeleton-containing phenoxy resin), and also "FX280" and "FX293" manufactured by Nippon Steel & Sumitomo Metal Corporation, "YX7553BH30", "YL7769BH30", "YL6794" manufactured by Mitsubishi Chemical Corporation, Examples thereof include "YL7213", "YL7290" and "YL7482".

As the acrylic resin, a functional group-containing acrylic resin is preferable, an epoxy group-containing acrylic resin is more preferable, and an epoxy group-containing acrylic acid ester copolymer resin is further preferable. When a functional group-containing acrylic resin is used as the acrylic resin, the functional group equivalent is preferably 1000 to 50,000, more preferably 2500 to 30000.

Specific examples of the acrylic resin include "SG-80H" and "SG-P3" (epoxy group-containing acrylic acid ester copolymer resin) manufactured by Nagase ChemteX Corporation.

Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, and polyvinyl butyral resin is preferable. Specific examples of the polyvinyl acetal resin include Electrified Butyral 4000-2, 5000-A, 6000-C, 6000-EP manufactured by Denki Kagaku Kogyo Co., Ltd., Eslek BH series and BX series manufactured by Sekisui Chemical Co., Ltd. KS series (specifically, "KS-1" etc.), BL series, BM series and the like can be mentioned.

Specific examples of the polyimide resin include "Ricacoat SN20" and "Ricacoat PN20" manufactured by NEW JAPAN CHEMICAL CO., LTD. Specific examples of the polyimide resin include a linear polyimide obtained by reacting a bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (Japanese Patent Laid-Open No. 2006-37083), and a polysiloxane skeleton-containing polyimide. Examples thereof include modified polyimides such as (Japanese Patent Laid-Open No. 2002-12667 and Japanese Patent Application Laid-Open No. 2000-319386).

Specific examples of the polyamide-imide resin include "Vilomax HR11NN" and "Vilomax HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of the polyamide-imide resin include modified polyamide-imides such as polysiloxane skeleton-containing polyamide-imides “KS9100” and “KS9300” manufactured by Hitachi Chemical Industries, Ltd.

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

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

The content of the thermoplastic resin in the first resin composition is not particularly limited, but is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, 5% by mass or more, or 7% by mass or more. The upper limit of the content of the thermoplastic resin is not particularly limited, but is preferably 30% by mass or less, more preferably 20% by mass or less, and further preferably 10% by mass or less.

-(E) Curing accelerator-
The first resin composition may further contain a curing accelerator. Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and the like, and phosphorus-based curing accelerators and amine-based curing agents. Curing accelerators and imidazole-based curing accelerators are preferable, and amine-based curing accelerators and imidazole-based curing accelerators are more preferable. The curing accelerator may be used alone or in combination of two or more.

Examples of the phosphorus-based curing accelerator include triphenylphosphine, phosphonium borate compound, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, and (4-methylphenyl) triphenylphosphonium thiocyanate. , Tetraphenylphosphonium thiocyanate, butyltriphenylphosphonium thiocyanate and the like, and triphenylphosphine and tetrabutylphosphonium decanoate are preferable.

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

Examples of the imidazole-based curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, and the like. 2-Ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-Cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl- 2-Phenylimidazolium trimellitate, 2,4-diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-undecyl Imidazolyl- (1')]-ethyl-s-triazine, 2,4-diamino-6- [2'-ethyl-4'-methylimidazolyl- (1')]-ethyl-s-triazine, 2,4- Diamino-6- [2'-methylimidazolyl- (1')]-ethyl-s-triazine isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole, 2- Phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazolin , 2-Imidazole compounds such as phenylimidazolin and adducts of imidazole compounds and epoxy resins are mentioned, 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, and examples thereof include "P200-H50" manufactured by Mitsubishi Chemical Corporation.

Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1- (o-tolyl) guanidine, dimethylguanidine, diphenylguanidine, and trimethylguanidine. Tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo [4.4.0] deca-5-ene, 7-methyl-1,5,7-triazabicyclo [4.4.0] Deca-5-ene, 1-methylbiguanide, 1-ethylbiguanide, 1-n-butylbiguanide, 1-n-octadecylviguanide, 1,1-dimethylbiguanide, 1,1-diethylbiguanide, 1-cyclohexylbiguanide, 1 Examples thereof include allylbiguanide, 1-phenylbiguanide, 1- (o-tolyl) biguanide, and dicyandiamide, 1,5,7-triazabicyclo [4.4.0] deca-5-ene is preferable.
Examples of the metal-based curing accelerator include organic metal complexes or organic metal salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin. Specific examples of the organometallic complex include organic cobalt complexes such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate, organic copper complexes such as copper (II) acetylacetonate, and zinc (II) acetylacetonate. Examples thereof include an organic zinc complex such as iron (III) acetylacetonate, an organic nickel complex such as nickel (II) acetylacetonate, and an organic manganese complex such as manganese (II) acetylacetonate. Examples of the organic metal salt include zinc octylate, tin octylate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate and the like.

The content of the curing accelerator in the first resin composition is not particularly limited, but is in the range of 0.05% by mass to 3% by mass when the total amount of the non-volatile components of the epoxy resin and the curing agent is 100% by mass. It is preferable to use it.

-(F) Flame retardant-
The first resin composition may further contain a flame retardant. Examples of the flame retardant include an organic phosphorus-based flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a silicone-based flame retardant, and a metal hydroxide. The flame retardant may be used alone or in combination of two or more.
As the flame retardant, a commercially available product may be used, and examples thereof include "HCA-HQ" manufactured by Sanko Co., Ltd.
The content of the flame retardant in the first resin composition layer is not particularly limited, but is preferably 0.5% by mass to 20% by mass, more preferably 1% by mass to 15% by mass, and further preferably 1.5% by mass. % To 10% by mass is more preferable.

-(G) Organic filler-
The first resin composition may further contain an organic filler. As the organic filler, any organic filler that can be used for forming the insulating layer of the printed wiring board may be used, and examples thereof include rubber particles, polyamide fine particles, and silicone particles, and rubber particles are preferable. As the rubber particles, a commercially available product may be used, and examples thereof include "AC3816N" manufactured by Aica Kogyo Co., Ltd.
The content of the organic filler in the first resin composition is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 10% by mass.

-Other ingredients-
The first resin composition may contain other additives, if necessary, and the other additives include, for example, an organic metal such as an organic copper compound, an organic zinc compound and an organic cobalt compound. Examples thereof include compounds, organic fillers, thickeners, defoaming agents, leveling agents, adhesion-imparting agents, resin additives such as colorants, and the like.

The thickness of the first resin composition layer is preferably 0.3 μm to 15 μm from the viewpoint of obtaining an insulating layer having high stability in roughness and peel strength. The lower limit of the thickness of the first resin composition layer is more preferably 0.5 μm or more, still more preferably 1 μm or more, 1.5 μm or more, 2 μm or more, 2.5 μm or more, or 3 μm or more. In particular, by setting the thickness of the first resin composition layer to 1 μm or more, the stability of roughness and peel strength can be further improved. The upper limit of the thickness of the first resin composition layer is more preferably 12 μm or less, still more preferably 10 μm or less, 9 μm or less, or 8 μm or less. The thickness of the first resin composition layer is preferably thinner than the thickness of the second resin composition layer.
The thickness of the first resin composition layer can be measured according to the procedure described later (measurement of the thickness of each layer of the resin sheet).

The minimum melt viscosity of the first resin composition layer is 3000 poise from the viewpoint that it is easy to maintain the desired thickness when laminated on the inner layer substrate, and by extension, an insulating layer having high stability of roughness and peel strength can be achieved. (300 Pa · s) or more is preferable, 5000 poise (500 Pa · s) or more is more preferable, and 10000 poise (1000 Pa · s) or more is further preferable. In particular, when the minimum melt viscosity is 5000 poise or more, an insulating layer exhibiting extremely good reflow resistance can be obtained. The upper limit of the minimum melt viscosity of the first resin composition layer is not particularly limited, but is preferably 100,000 poise (10000 Pa · s) or less, more preferably 80,000 poise (8000 Pa · s) or less, and 50,000 poise (5000 Pa · s) or less. More preferred.

The minimum melt viscosity of the first resin composition layer means the minimum viscosity exhibited by the resin composition layer when the resin of the first resin composition layer is melted. Specifically, when the first resin composition layer is heated at a constant temperature rise rate to melt the resin, the melt viscosity decreases with increasing temperature in the initial stage, and then melts with increasing temperature when the temperature exceeds a certain level. Viscosity increases. The minimum melt viscosity means the melt viscosity at such a minimum point. The minimum melt viscosity of the first resin composition layer is, for example, a dynamic viscoelasticity measuring device (“Rheosol-G3000” manufactured by UBM Co., Ltd.), and the diameter of 1 g of the sample resin composition is 18 mm. Using the parallel plate of No. 1, the temperature is raised from 60 ° C. to 200 ° C. at a heating rate of 5 ° C./min, and the measurement is performed under the measurement conditions of a measurement temperature interval of 2.5 ° C., a frequency of 1 Hz, and a strain of 1 deg. be able to. The same applies to the definition and measurement method of the minimum melt viscosity of the second resin composition layer.

<Second resin composition layer>
The resin sheet of the present invention has a second resin composition layer made of the second resin composition. The second resin composition layer affects the bulk properties of the resulting insulating layer.

The second resin composition contains an inorganic filler from the viewpoint of reducing the coefficient of thermal expansion of the obtained insulating layer and preventing the occurrence of cracks and circuit distortion due to the difference in thermal expansion between the insulating layer and the conductor layer. Is preferable. The content of the inorganic filler in the second resin composition is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 60% by mass, from the viewpoint of reducing the coefficient of thermal expansion of the obtained insulating layer. % Or more, 62% by mass or more, 64% by mass or more, 66% by mass or more, 68% by mass or more, or 70% by mass or more. The upper limit of the content of the inorganic filler in the second resin composition is preferably 96% by mass or less, more preferably 95% by mass or less, still more preferably 90% by mass, from the viewpoint of the mechanical strength of the obtained insulating layer. It is less than or equal to 85% by mass or less.

In one preferred embodiment, the content of the inorganic filler in the second resin composition is higher than the content of the inorganic filler in the first resin composition. Assuming that the content of the inorganic filler in the first resin composition is A1 (mass%) and the content of the inorganic filler in the second resin composition is A2 (mass%), the difference between A1 and A2 (mass%). A2-A1) is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, 25% by mass or more, or 30% by mass or more. The upper limit of the difference (A2-A1) is not particularly limited, but may be usually 90% by mass or less, 80% by mass or less, and the like. Regarding the conventional resin sheet, the present inventors have found that when the difference (A2-A1) is increased, delamination is likely to occur in the insulating layer when exposed to a high temperature environment such as during reflow. On the other hand, the insulating layer formed by using the resin sheet of the present invention having a mixed layer can suppress delamination even when the value of the difference (A2-A1) is large. Therefore, in the present invention, the degree of freedom in designing the composition of each layer is high, and it is possible to advantageously impart the desired function to each layer. Further, when A1 and A2 are different in this way, it becomes easier to grasp the mixed layer described later.

Examples of the inorganic filler include the inorganic filler described for the first resin composition, of which silica is preferable, and spherical silica is more preferable. The average particle size of the inorganic filler contained in the second resin composition is in the range of 0.01 μm to 5 μm from the viewpoint of increasing the fluidity of the second resin composition layer and realizing sufficient circuit embedding property. The range of 0.05 μm to 2 μm is more preferable, the range of 0.1 μm to 1 μm is further preferable, and the range of 0.2 μm to 0.8 μm is even more preferable. Examples of commercially available inorganic fillers having such an average particle size include "SOC4", "SOC2", and "SOC1" manufactured by Admatex Co., Ltd.

The inorganic filler contained in the second resin composition is preferably treated with a surface treatment agent. The type of surface treatment agent and the degree of surface treatment are as described in the <First Resin Composition Layer> column.

Examples of other materials contained in the second resin composition include (a) a curable resin such as an epoxy resin and (b) a curing agent described in the column <1st resin composition layer>. Can be mentioned. Therefore, in one embodiment, the second resin composition comprises (a) an epoxy resin, (b) a curing agent and (c) an inorganic filler. Preferable examples of each component are as described in the column <1st resin composition layer>, and among them, the 2nd resin composition is (a) a liquid epoxy resin and a solid epoxy resin as the epoxy resin. (The mass ratio of the liquid epoxy resin: the solid epoxy resin is preferably in the range of 1: 0.1 to 1: 4, more preferably in the range of 1: 0.3 to 1: 3.5, and 1: 0. The range of .6 to 1: 3 is more preferable, and the range of 1: 0.8 to 1: 2.5 is particularly preferable). One or more selected from the group consisting of a curing agent and a cyanate ester-based curing agent (preferably one or more selected from the group consisting of a phenol-based curing agent, a naphthol-based curing agent and an active ester-based curing agent). c) It is preferable to contain silica as the inorganic filler.

The content of the (a) epoxy resin in the second resin composition is not particularly limited, but is preferably 3% by mass to 50% by mass, more preferably 5% by mass to 45% by mass, and further preferably 5% by mass to 5% by mass. It is 40% by mass, and even more preferably 7% by mass to 35% by mass.

The amount ratio of the (a) epoxy resin to the (b) curing agent in the second resin composition may be the same as that described in the <1st resin composition layer> column.
The content of the curing agent (b) in the second resin composition is not particularly limited, but is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less, still more preferably 15. It is 10% by mass or less by mass. The lower limit is not particularly limited, but is preferably 3% by mass or more.

The second resin composition may further contain one or more components selected from the group consisting of (d) a thermoplastic resin, (e) a curing accelerator, (f) a flame retardant and (g) an organic filler. good. Suitable examples of these components (d) to (g) are as described in the <First Resin Composition Layer> column.
The content of the (d) thermoplastic resin in the second resin composition is not particularly limited, but is preferably 0.1% by mass to 20% by mass, and more preferably 0.5% by mass to 10% by mass.
The content of the (e) curing accelerator in the second resin composition is preferably 0.05% by mass when the total amount of the non-volatile components of (a) the epoxy resin and (b) the curing agent is 100% by mass. ~ 3% by mass.
The content of the flame retardant (f) in the second resin composition is not particularly limited, but is preferably 0.5% by mass to 10% by mass, more preferably 1% by mass to 9% by mass, and even more preferably 1. It is 5.5% by mass to 8% by mass.
The content of the (g) organic filler in the second resin composition is not particularly limited, but is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 5% by mass.

The second resin composition may contain other additives, if necessary, and the other additives include, for example, an organic metal such as an organic copper compound, an organic zinc compound and an organic cobalt compound. Examples thereof include compounds, organic fillers, thickeners, defoaming agents, leveling agents, adhesion-imparting agents, resin additives such as colorants, and the like.

The thickness of the second resin composition layer is not particularly limited as long as an insulating layer having a desired thickness can be obtained, but is preferably 3 μm to 200 μm. The lower limit of the thickness of the second resin composition layer is more preferably 5 μm or more, still more preferably 10 μm or more, or 15 μm or more. The upper limit of the thickness of the second resin composition layer is more preferably 180 μm or less, still more preferably 160 μm or less, 150 μm or less, 140 μm or less, 120 μm or less, or 100 μm or less.
The thickness of the second resin composition layer can be measured according to the procedure described later (measurement of the thickness of each layer of the resin sheet).

The minimum melt viscosity of the second resin composition layer is preferably 10,000 poise (1000 Pa · s) or less, more preferably 8,000 poise (800 Pa · s) or less, and 5000 poise (500 Pa · s) from the viewpoint of obtaining good circuit embedding property. ) The following is more preferable. The lower limit is not particularly limited, but 500 poise (50 Pa · s) or more is preferable, 800 poise (80 Pa · s) or more is more preferable, and 1000 poise (100 Pa · s) or more is further preferable.

<Mixed layer>
The resin sheet of the present invention has a mixed layer in which the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer.

The thickness of the mixed layer is 0.4 μm or more, preferably 0.5 μm or more, and more preferably 1.0 μm or more, from the viewpoint of obtaining an insulating layer in which delamination is suppressed in a high temperature environment such as during reflow. The upper limit of the thickness of the mixed layer is not particularly limited, but is preferably twice or less the thickness of the first resin composition layer. For example, assuming that the thickness of the first resin composition layer is t (μm), the thickness of the mixed layer is preferably 2t or less, more preferably 1.5t or less, still more preferably t or less, 0.9t or less, 0. It is 0.8t or less, or 0.7t or less. The thickness of the mixed layer is more preferably 10 μm or less, further preferably 5 μm or less, and particularly preferably 3 μm or less as long as it is 2 tons or less.
The thickness of the mixed layer can be measured according to the procedure described later (Measurement of the thickness of each layer of the resin sheet). The mixed layer can be grasped as a region having a composition different from that of the first resin composition layer and the second resin composition layer. For example, when the content A1 of the inorganic filler in the first resin composition layer and the content A2 of the inorganic filler in the second resin composition layer satisfy the relationship of A1 <A2, the cross section of the resin sheet. In SEM observation, the mixed layer can be grasped as follows. That is, in the cross section of the resin sheet, the inorganic filler / resin component ratio is constant in the region where the distance from the bonding interface with the support is 0 to t1, and the distance from the bonding interface with the support is t1 to t2. In the region up to, the inorganic filler / resin component ratio gradually increases, and in the region where the distance from the interface with the support is t2 to t3, the inorganic filler / resin component ratio is constant. The position of the distance t3 from the bonding interface with the support is the surface position of the resin composition layer on the opposite side of the support. In such a case, the region where the distance from the bonding interface with the support is 0 to t1 is the first resin composition layer, the region where the distance is from t1 to t2 is the mixed layer, and the distance is t2. The region from to t3 is the second resin composition layer. Alternatively, if the particle size of the inorganic filler in the first resin composition layer is different from the particle size of the inorganic filler in the second resin composition layer, the particle size of the inorganic filler is changed. It is also possible to grasp the mixed layer from the viewpoint of.

The resin sheet of the present invention may further contain a protective film on the surface of the second resin composition layer. The protective film contributes to the prevention of dust and the like and scratches on the surface of the second resin composition layer. As the material of the protective film, the same material as described for the support may be used. The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. The resin sheet with a support can be used by peeling off the protective film when manufacturing the printed wiring board.

The resin sheet of the present invention is used to form an insulating layer of a metal-clad laminate (for an insulating layer of a metal-clad laminate) and to form an insulating layer of a printed wiring board (for an insulating layer of a printed wiring board). can do. Above all, in the manufacture of printed wiring boards by the build-up method, it can be suitably used for forming an insulating layer (for the build-up insulating layer of a printed wiring board), and for forming a conductor layer by plating (by plating). It can be more preferably used for a build-up insulating layer of a printed wiring board forming a conductor layer).

-Other embodiments-
In the present invention, in a resin sheet containing a plurality of resin composition layers, a layer in which the components of each resin composition layer are mixed is provided in a region where the resin composition layers are in contact with each other. Thereby, the present invention realizes an insulating layer in which delamination is suppressed in a high temperature environment. Although the embodiment including the two resin composition layers has been described above, a resin sheet containing a more multi-layered resin composition layer may be obtained by using the concept of the present invention. For example, a resin sheet containing three resin composition layers of a first resin composition layer, a second resin composition layer, and an additional resin composition layer (third resin composition layer) can be obtained. In such a case, a mixed layer may be provided between the first resin composition layer and the third resin composition layer, and between the second resin composition layer and the third resin composition layer, respectively. Even in the resin sheet containing three or more resin composition layers, the suitable composition and thickness of the first resin composition layer to be bonded to the support are as described in the above <first resin composition layer>. be. Further, the suitable composition of the resin composition layer to be bonded to the inner layer substrate is as described in the above <second resin composition layer>. Specifically, the support \ the first resin composition layer \ the first mixed layer \ the additional resin composition layer (third resin composition layer) \ the second mixed layer \ the second resin composition layer A resin sheet having the above layer structure can be obtained. In such a resin sheet, the composition and thickness of the additional resin composition layer may be appropriately determined according to the design of the desired printed wiring board. According to the present invention in which a mixed layer is provided, an insulating layer having an desired function is provided even when an additional resin composition layer exhibiting expansion characteristics significantly different from that of the first and second resin composition layers is provided. Can be advantageously achieved without delamination in a high temperature environment. The additional resin composition layer may be, for example, a resin composition layer containing glass fiber or the like in order to impart a new function to the resin sheet.

[Manufacturing method of resin sheet]
As described above, the resin sheet of the present invention is formed on the support, the first resin composition layer composed of the first resin composition formed on the support, and the first resin composition layer. It has a second resin composition layer made of a second resin composition, and a first resin composition and a second resin composition are placed between the first resin composition layer and the second resin composition layer. It has a mixed layer in which the resin composition of the above is mixed. In such a method for producing a resin sheet, a first resin varnish in which a first resin composition is dissolved is applied onto a support, and a second resin composition is dissolved in the first resin varnish. 2. The step of applying and drying the resin varnish is included, and the first resin varnish has a viscosity of 100 mPa · s or more, and the second resin varnish has a viscosity of 100 mPa · s or more.

Conventionally, for example, in the resin sheet described in JP-A-2014-17301, a first resin varnish in which a first resin composition is dissolved is applied onto a support to form a first resin composition layer. Later, a second resin varnish in which the second resin composition was dissolved was applied onto the first resin composition layer to form the second resin composition layer (hereinafter, "double coating method"). Also called).
In the present invention, the first resin varnish and the second resin varnish are applied on the same coating line. Specifically, the second resin varnish is applied onto the first resin varnish rather than on the first resin composition layer. That is, the second resin varnish is applied before forming the first resin composition layer. As a result, between the first resin composition layer and the second resin composition layer, the first resin composition contained in the first resin varnish and the second resin composition contained in the second resin varnish are contained. It is possible to form a mixed layer in which the resin composition is mixed.

The method for producing a resin sheet of the present invention is not particularly limited as long as the desired mixed layer can be formed by applying the second resin varnish on the first resin varnish. In one preferred embodiment, the method for producing a resin sheet of the present invention is:
A step of applying the first resin varnish on the support and at the same time applying the second resin varnish on the first resin varnish and then drying is included, or the first resin varnish is applied on the support. The process includes a step of applying a second resin varnish on the first resin varnish after pre-drying, and then drying.
Hereinafter, the method including the former process is also referred to as "simultaneous coating method", and the method including the latter process is also referred to as "tandem coating method". Both the simultaneous coating method and the tandem coating method are different from the conventional double coating method in that the first resin varnish and the second resin varnish are applied on the same coating line.

Hereinafter, the simultaneous coating method and the tandem coating method, which are preferred embodiments of the method for producing a resin sheet of the present invention, will be described with reference to FIGS. 2 and 3.

<Simultaneous coating method>
FIG. 2 shows an example of a resin sheet manufacturing apparatus in the simultaneous coating method. The resin sheet manufacturing apparatus 100 shown in FIG. 2 includes a coating apparatus 101 and a drying apparatus 102. In the device 100, the support 11 is supplied to the coating device 101. The coating device 101 applies the first resin varnish on the support 11 and at the same time applies the second resin varnish on the first resin varnish. The support coated with the first and second resin varnishes is supplied to the drying device 102. The drying device 102 dries the first and second resin varnishes applied on the support. If necessary, wind the resin sheet into a roll. As a result, a first resin composition layer derived from the first resin varnish and a second resin composition layer derived from the second resin varnish are formed on the support, and the first resin composition layer and the first resin composition layer are formed. A mixed layer obtained by mixing the first resin varnish and the second resin varnish is formed between the two resin composition layers.

In the simultaneous coating method, the heat history in the production of the resin sheet can be suppressed, and the heat shrinkage of the support can be suppressed. As a result, the resin sheet formed by the simultaneous coating method can provide an insulating layer having excellent stability of roughness and peel strength. Further, in the simultaneous coating method, since the first and second resin varnishes are applied at the same time, it is easy to form a thick mixed layer. Therefore, the resin sheet produced by the simultaneous coating method can provide an insulating layer having better reflow resistance.

In the simultaneous coating method, the first and second resin varnishes are applied using a known coating device capable of applying the first resin varnish and at the same time applying the second resin varnish on the first resin varnish. Can be done. For example, it can be applied using a known multi-slit coating system such as a multi-slit type die coater provided with a slit for applying the first resin varnish and a slit for applying the second resin varnish.

The first and second resin varnishes can be prepared by dissolving the first and second resin compositions in a solvent, respectively. The solvent used for preparing the resin varnish is not particularly limited, but an organic solvent is preferable. Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone and cyclohexanone, acetate esters such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate, and carbitol such as cellosolve and butyl carbitol. Examples include aromatic hydrocarbons such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone, and solvent naphtha. The organic solvent may be used alone or in combination of two or more.
Further, the solvent that dissolves the first resin composition and the solvent that dissolves the second resin composition may be the same or different.
The solvent contained in the first and second resin varnishes is preferably 75% by mass or less, more preferably 65% by mass or less, still more preferably, when the total of the non-volatile components contained in the resin varnish is 100% by mass. Is adjusted to be 55% by mass or less, particularly preferably 45% by mass or less. The lower limit is preferably 15% by mass or more, more preferably 20% by mass or more, from the viewpoint of promoting the formation of the mixed layer.

The viscosity of the first resin varnish improves the affinity with the support from the viewpoint that the thickness of the first resin composition layer can be easily controlled, and the first resin varnish is applied without the generation of cissing or streaks. From a possible viewpoint, it is 100 mPa · s or more, preferably 200 mPa · s or more, and more preferably 300 mPa · s or more. The upper limit of the viscosity of the first resin varnish is not particularly limited, but 3000 mPa · s or less is preferable, and 2000 mPa · s or less is preferable from the viewpoint that the thickness of the first resin composition layer can be easily controlled and thinned. Is more preferable, and 1000 mPa · s or less is further preferable.

The viscosity of the second resin varnish is 100 mPa · s or more, preferably 200 mPa · s or more, and more preferably 300 mPa · s or more, from the viewpoint that the thickness of the second resin composition layer can be easily controlled. The upper limit of the viscosity of the second resin varnish is not particularly limited, but is preferably 6000 mPa · s or less, preferably 3000 mPa · s or less, from the viewpoint that the thickness of the second resin composition layer can be easily controlled and thinned. Is more preferable, and 1000 mPa · s or less is further preferable.
The viscosities of the first and second resin varnishes can be measured, for example, using a rotary (E-type) viscometer. Examples of the rotary (E-type) viscometer include "RE-80U" manufactured by Toki Sangyo Co., Ltd.

The first and second resin varnishes may be dried by a known drying method such as heating or blowing hot air. The drying conditions are not particularly limited, but the amount of residual solvent in the resin sheet after drying is 100% by mass of the total of the non-volatile components contained in the first resin composition layer, the mixed layer and the second resin composition layer. When it is, it is dried so that it is preferably 10% by mass or less, more preferably 5% by mass or less. The lower limit of the residual solvent amount is not particularly limited, but may be usually 0.1% by mass or more, 0.5% by mass or more, and the like. Depending on the boiling point of the organic solvent in the first and second resin varnishes, for example, when the first and second resin varnishes containing 30% by mass to 60% by mass of the organic solvent are used, the temperature is 50 ° C. to 150 ° C. The resin sheet of the present invention can be produced by drying for 3 to 10 minutes.

<Tandem coating method>
FIG. 3 shows an example of a resin sheet manufacturing apparatus in the tandem coating method. The resin sheet manufacturing apparatus 200 shown in FIG. 3 includes a first coating apparatus 201, a pre-drying apparatus 202, a second coating apparatus 203, and a drying apparatus 204. In the manufacturing apparatus 200, the support 11 is supplied to the first coating apparatus 201. The first coating device 201 coats the first resin varnish on the support 11. The support coated with the first resin varnish is supplied to the pre-drying device 202. The pre-drying device 202 pre-drys the first resin varnish. After pre-drying the first resin varnish, the support is fed to the second coating device 203. The second coating device 203 coats the second resin varnish on the first resin varnish. Then, the support coated with the first and second resin varnishes is supplied to the drying device 204. The drying device 204 dries the first and second resin varnishes applied on the support. If necessary, wind the resin sheet into a roll. As a result, a first resin composition layer derived from the first resin varnish and a second resin composition layer derived from the second resin varnish are formed on the support, and the first resin composition layer and the first resin composition layer are formed. A mixed layer obtained by mixing the first resin varnish and the second resin varnish is formed between the two resin composition layers.

In the tandem coating method, since the first resin varnish is pre-dried, the accuracy of the thickness of the first resin composition layer can be improved.

In the tandem coating method, the pre-drying is not particularly limited as long as the formation of the mixed layer by mixing the first resin varnish and the second resin varnish is not hindered, and a known drying method such as heating or hot air blowing is used. It may be carried out. The pre-drying conditions are not particularly limited, but the amount of residual solvent in the first resin varnish after drying is preferably 70% by mass when the total of the non-volatile components contained in the first resin varnish is 100% by mass. Below, it is pre-dried so as to be more preferably 60% by mass or less, further preferably 50% by mass or less, and particularly preferably 40% by mass or less. The lower limit of the residual solvent amount is preferably 15% by mass or more, more preferably 20% by mass or more, still more preferably 25% by mass or more, from the viewpoint of promoting the formation of the mixed layer. Although it depends on the boiling point of the organic solvent in the first resin varnish, for example, when the first resin varnish containing 30% by mass to 60% by mass of the organic solvent is used, the temperature is 50 ° C. to 150 ° C. for 0.1 minutes to 3 It is preferable to dry for a minute (more preferably 60 ° C. to 130 ° C. for 0.2 minutes to 2 minutes, still more preferably 70 ° C. to 120 ° C. for 0.3 minutes to 1.5 minutes).

The first and second resin varnishes (viscosity, solvent type, etc.) are as described in the simultaneous coating method. Further, the drying after applying the second resin varnish may be carried out under the same conditions as the drying in the simultaneous coating method.

The method for producing a resin sheet of the present invention may further include a step of laminating a protective film on the surface of the second resin composition layer (the surface opposite to the support side). The details of the protective film are as described above.

[Printed circuit board and its manufacturing method]
A printed wiring board can be manufactured using the resin sheet manufactured by the method of the present invention. For example, a printed wiring board can be manufactured by laminating the resin sheet manufactured by the method of the present invention on an inner layer substrate, heat-curing the resin sheet, and then removing the support. Therefore, the printed wiring board of the present invention is characterized by including an insulating layer formed by using the resin sheet of the present invention.

Specifically, the printed wiring board of the present invention can be manufactured by a method including the following steps (I) to (III) using the resin sheet of the present invention.
(I) A step of laminating the resin sheet of the present invention on the inner layer substrate so that the second resin composition layer is bonded to the inner layer substrate (II) A step of thermally curing the resin sheet to form an insulating layer (III) ) Step to remove the support

In the step (I), the resin sheet of the present invention is laminated on the inner layer substrate so that the second resin composition layer is bonded to the inner layer substrate.

The "inner layer substrate" used in the step (I) is mainly a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a heat-curable polyphenylene ether substrate or the like, or one or both sides of the substrate. A circuit board on which a conductor layer (circuit) that has been patterned is formed. Further, the inner layer circuit board of the intermediate product in which the insulating layer and / or the conductor layer should be further formed when the printed wiring board is manufactured is also included in the "inner layer board" in the present invention.

The laminating of the resin sheet and the inner layer substrate in the step (I) may be carried out by any conventionally known method, but the second resin composition layer may be bonded to the inner layer substrate by roll crimping, press crimping, or the like. It is preferable to laminate the resin.

The laminating treatment is preferably roll crimping, press crimping, or the like. Above all, the vacuum laminating method of laminating under reduced pressure is more preferable. The laminating method may be a batch method or a continuous method.

Lamination generally crimping pressure of ^{1kgf / cm 2 ~11kgf / cm 2} (9.8 × 10 4 N / m 2 ~107.9 × 10 4 N / m 2) range, 70 ° C. The bonding temperature It is preferable that the pressure is in the range of ~ 120 ° C., the crimping time is in the range of 5 seconds to 180 seconds, and the pressure is reduced to 20 mmHg (26.7 hPa) or less.

The laminating process can be carried out using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include a vacuum pressurizing laminator manufactured by Meiki Seisakusho Co., Ltd., a vacuum applicator manufactured by Nichigo Morton Co., Ltd., and the like.
It is preferable to perform laminating treatment via an elastic material such as heat-resistant rubber so that the resin sheet sufficiently follows the surface unevenness of the inner layer substrate (for example, the unevenness of the surface circuit of the inner layer circuit board).

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

After the step (I), the resin sheet laminated on the inner layer substrate may be heated and pressed to smooth it. The smoothing treatment is generally carried out by heating and pressurizing the resin sheet with a heated metal plate or metal roll under normal pressure (atmospheric pressure). As the heating and pressurizing conditions, the same conditions as the above-mentioned laminating treatment conditions can be used. The laminating treatment and the smoothing treatment may be continuously carried out using a commercially available vacuum laminator.

In step (II), the resin sheet is thermally cured to form an insulating layer. Specifically, the first resin composition layer, the mixed layer, and the second resin composition layer of the laminated resin sheets are thermoset to form an insulating layer.

The conditions for thermosetting are not particularly limited, and the conditions usually adopted when forming the insulating layer of the printed wiring board may be used.

For example, the thermosetting conditions of the resin sheet differ depending on the composition of the resin composition constituting the first and second resin composition layers, but the curing temperature is in the range of 120 ° C. to 240 ° C. (preferably 150 ° C. to 210 ° C.). The temperature may be in the range of ° C., more preferably in the range of 170 ° C. to 190 ° C., and the curing time may be in the range of 5 minutes to 90 minutes (preferably 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes).

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

In step (III), the support is removed. This exposes the surface of the insulating layer. The support may be removed manually or mechanically using an automatic peeling device or the like. When a metal leaf is used as the support, it may be removed by using a chemical.

When manufacturing a printed wiring board, even if (IV) a step of drilling a hole in the insulating layer, (V) a step of roughening the insulating layer, and (VI) a step of forming a conductor layer on the surface of the insulating layer are further carried out. good. These steps (IV) to (VI) may be carried out according to various methods known to those skilled in the art used for manufacturing a printed wiring board. The support may be removed between steps (II) and step (IV), between steps (IV) and step (V), or between steps (V) and step (VI). good.

The step (IV) is a step of drilling holes in the insulating layer, whereby holes such as via holes and through holes can be formed in the insulating layer. For example, a drill, a laser (carbon dioxide laser, YAG laser, etc.), plasma, or the like can be used to form a hole in the insulating layer.

The step (V) is a step of roughening the insulating layer. The procedure and conditions of the roughening treatment are not particularly limited, and known procedures and conditions usually used when forming the insulating layer of the printed wiring board can be adopted. For example, the insulating layer can be roughened by performing a swelling treatment with a swelling liquid, a roughening treatment with an oxidizing agent, and a neutralization treatment with a neutralizing liquid in this order. The swelling solution is not particularly limited, and examples thereof include an alkaline solution and a surfactant solution, preferably an alkaline solution, and the alkaline solution is more preferably a sodium hydroxide solution or a potassium hydroxide solution. Examples of commercially available swelling liquids include Swelling Dip Security Guns P and Swelling Dip Security Guns SBU manufactured by Atotech Japan Co., Ltd. The swelling treatment with the swelling liquid is not particularly limited, but can be performed, for example, by immersing the insulating layer in the swelling liquid at 30 ° C. to 90 ° C. for 1 minute to 20 minutes. The oxidizing agent is not particularly limited, and examples thereof include 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 in an oxidizing agent solution heated to 60 ° C to 80 ° C for 10 to 30 minutes. The concentration of permanganate 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 CP and Dozing Solution Security P manufactured by Atotech Japan Co., Ltd. The neutralizing solution is preferably an acidic aqueous solution, and examples of commercially available products include Reduction Solution Securigant P manufactured by Atotech Japan Co., Ltd. The treatment with the neutralizing solution can be performed by immersing the treated surface roughened with the oxidizing agent solution in the neutralizing solution at 30 ° C. to 80 ° C. for 5 to 30 minutes.

In one embodiment, the arithmetic average roughness Ra of the surface of the insulating layer after the roughening treatment is preferably 400 nm or less, more preferably 350 nm or less, still more preferably 300 nm or less, 250 nm or less, 200 nm or less, 150 nm or less, or 100 nm or less. Is. The insulating layer formed by using the resin sheet of the present invention exhibits excellent peel strength with respect to the conductor layer even when Ra is small as described above. The lower limit of the Ra value is not particularly limited, but may be usually 0.5 nm or more, 1 nm or more, or the like. When there are variations in Ra on the surface of the insulating layer after the roughening treatment, _{it is preferable that the maximum value of Ra (Ra max} ) is in the above range.

Further, in the present invention, it is possible to form an insulating layer having little variation in surface roughness after the roughening treatment and having high roughness stability. In one embodiment, the difference between _{the maximum value (Ra max} ) and the minimum value (Ra _min ) of the arithmetic mean roughness of the surface of the insulating layer after the roughening treatment, _{Ra max} −Ra _min, is preferably 150 nm or less, more preferably 100 nm. Below, it is more preferably 80 nm or less, 60 nm or less, 40 nm or less, or 30 nm or less. The lower limit of the difference Ra _max −Ra _min is preferably low and may be 0 nm, but usually it may be 0.1 nm or more, 0.5 nm or more, and the like.

The arithmetic average roughness Ra of the surface of the insulating layer can be measured using a non-contact type surface roughness meter. Specific examples of the non-contact type surface roughness meter include "WYKO NT3300" manufactured by Becoin Sturments.

The step (VI) is a step of forming a conductor layer on the surface of the insulating layer.

The conductor material used for the conductor layer is not particularly limited. In a preferred embodiment, the conductor layer is one or more selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium. Contains metal. The conductor layer may be a single metal layer or an alloy layer, and the alloy layer may be, for example, an alloy of two or more metals selected from the above group (for example, nickel-chromium alloy, copper, etc.). Examples include layers formed from nickel alloys and copper-titanium alloys). Among them, from the viewpoint of versatility, cost, ease of patterning, etc. for forming a conductor layer, a single metal layer of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper, or a nickel-chromium alloy, copper, etc. A nickel alloy, a copper-titanium alloy alloy layer is preferable, a chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper single metal layer, or a nickel-chromium alloy alloy layer is more preferable, and a copper single metal layer is preferable. A metal layer is more preferred.

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

The thickness of the conductor layer depends on the desired printed wiring board design, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

The conductor layer may be formed by plating. For example, the surface of the insulating layer can be plated by a conventionally known technique such as a semi-additive method or a full additive method to form a conductor layer having a desired wiring pattern. Hereinafter, an example of forming the conductor layer by the semi-additive method will be shown.

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

In one embodiment, the peel strength between the insulating layer and the conductor layer after the roughening treatment is preferably 0.4 kgf / cm or more, more preferably 0.45 kgf / cm or more, still more preferably 0.50 kgf / cm or more. be. On the other hand, the upper limit of the peel strength is not particularly limited, but is 1.2 kgf / cm or less, 0.9 kgf / cm or less, and the like. In the present invention, although the surface roughness Ra of the insulating layer after the roughening treatment is small, the insulating layer exhibiting such high peel strength can be formed, which is remarkable for fine wiring of the printed wiring board. It contributes. When there are variations in the peel strength between the insulating layer and the conductor layer, _{it is preferable that the minimum value (S min} ) of the peel strength is within the above range.

Further, in the present invention, it is possible to form an insulating layer having a high stability of peel strength with little variation in peel strength between the insulating layer and the conductor layer. In one embodiment, the difference S _max −S _{min between the maximum value (S max} ) and the minimum value (S _min ) of the peel strength between the insulating layer and the conductor layer is preferably 0.15 kgf / cm or less, more preferably 0. .1 kgf / cm or less. The lower limit of the difference S _max −S _min is preferably low and may be 0 kgf / cm, but usually 0.01 kgf / cm or more, 0.05 kgf / cm or more, and the like.

In the present invention, the peel strength between the insulating layer and the conductor layer means the peel strength (90 degree peel strength) when the conductor layer is peeled in the direction perpendicular to the insulating layer (90 degree direction). The peel strength when the conductor layer is peeled off in the direction perpendicular to the insulating layer (90 degree direction) can be obtained by measuring with a tensile tester. Examples of the tensile tester include "AC-50C-SL" manufactured by TSE Co., Ltd.

[Semiconductor device]
The semiconductor device of the present invention is characterized by including the printed wiring board of the present invention, and the semiconductor device can be manufactured by using the printed wiring board of the present invention. By using the printed wiring board of the present invention, delamination of the insulating layer can be advantageously suppressed even in the mounting process where a high solder reflow temperature is adopted, and the stability of the peel strength between the insulating layer and the conductor layer can be suppressed. Combined with the height, high reflow reliability can be achieved.

Examples of such semiconductor devices include various semiconductor devices used in electric products (for example, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (for example, 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. The "conduction point" is a "place for transmitting an electric signal in the printed wiring board", and the place may be a surface or an embedded place. Further, the semiconductor chip is not particularly limited as long as it is an electric circuit element made of a semiconductor.

The method for mounting a semiconductor chip in manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively, but specifically, a wire bonding mounting method, a flip chip mounting method, and no bumps. Examples thereof include a mounting method using a build-up layer (BBUL), a mounting method using an anisotropic conductive film (ACF), and a mounting method using a non-conductive film (NCF). Here, the "mounting method using the bumpless build-up layer (BBUL)" means "a mounting method in which the semiconductor chip is directly embedded in the recess of the printed wiring board and the semiconductor chip is connected to the wiring on the printed wiring board". Is.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In the following description, "parts" and "%" mean "parts by mass" and "% by mass", respectively, unless otherwise specified.

(Preparation of resin varnish 1)
10 parts of naphthylene ether type epoxy resin ("EXA-7311-G4S" manufactured by DIC Co., Ltd., epoxy equivalent 186), 10 parts of bixilenol type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent of about 185) , 20 parts of biphenyl type epoxy resin (“NC3000H” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 288), and phenoxy resin (“YX7553BH30” manufactured by Mitsubishi Chemical Co., Ltd., cyclohexanone with a solid content of 30% by mass: methyl ethyl ketone (MEK)). 25 parts of the 1: 1 solution) was heated and dissolved in a mixed solvent of 15 parts of solvent naphtha and 5 parts of cyclohexanone with stirring. After cooling to room temperature, there, 12 parts of a triazine skeleton-containing phenol novolac-based curing agent (hydroxyl equivalent 125, "LA-7054" manufactured by DIC Co., Ltd., MEK solution having a solid content of 60%), and a naphthol-based curing agent ( "SN485" manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., 15 parts of MEK solution having a hydroxyl group equivalent of 215 and a solid content of 60%), polyvinyl butyral resin (glass transition temperature 105 ° C., "KS-1" manufactured by Sekisui Chemical Industry Co., Ltd.) 10 parts of 1: 1 mixed solution of ethanol with solid content of 15% and toluene, 1 part of amine-based curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with 5% by mass of solid content), imidazole-based curing accelerator ("P200-H50" manufactured by Mitsubishi Chemical Co., Ltd., propylene glycol monomethyl ether solution having a solid content of 50% by mass) and 4 parts of rubber particles (AC3816N manufactured by Aika Kogyo Co., Ltd.) in 20 parts of MEK at room temperature for 12 hours. Swelled, spherical silica surface-treated with an aminosilane-based coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Industry Co., Ltd.) ("SOC2" manufactured by Admatex Co., Ltd., average particle size 0.5 μm, unit 50 parts of carbon per surface area 0.38 mg / m ² ) were mixed, uniformly dispersed with a high-speed rotary mixer, and then filtered with a cartridge filter (“SHP050” manufactured by ROKITECHNO) to prepare a resin varnish 1.

(Preparation of resin varnish 2)
Bisphenol AF type epoxy resin ("YL7760" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 238) 10 parts, bixylenol type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Co., Ltd., epoxy equivalent about 185) 6 parts, biphenyl type epoxy 30 parts of resin (“NC3000H” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 288), and phenoxy resin (“YX7553BH30” manufactured by Mitsubishi Chemical Corporation, cyclohexanone with a solid content of 30% by mass: 1: 1 of methyl ethyl ketone (MEK)). 5 parts of solution), 20 parts of phenoxy resin (“YL7769BH30” manufactured by Mitsubishi Chemical Corporation, 1: 1 solution of cyclohexanone with a solid content of 30% by mass: methyl ethyl ketone (MEK)) in a mixed solvent of 20 parts of MEK and 5 parts of cyclohexanone. It was dissolved by heating with stirring. After cooling to room temperature, 20 parts of an active ester-based curing agent (“HPC8000-65T” manufactured by DIC Co., Ltd., an active group equivalent of about 223, a toluene solution having a non-volatile component of 65% by mass), an amine-based curing accelerator (4-Dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass) 4 parts, imidazole-based curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with a solid content of 5% by mass) 3 Spherical silica surface-treated with phenyltrimethoxysilane ("KBM103" manufactured by Shinetsu Chemical Industry Co., Ltd.) ("UFP-30" manufactured by Electrochemical Industry Co., Ltd., average particle size 0.1 μm, per unit surface area 45 parts of carbon amount 0.22 mg / m ² ) was mixed, uniformly dispersed with a high-speed rotary mixer, and then filtered with a cartridge filter (“SHP030” manufactured by ROKITECHNO) to prepare a resin varnish 2.

(Preparation of resin varnish 3)
In the preparation of the resin varnish 2, the blending amount of the amine-based curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution having a solid content of 5% by mass) was changed from 4 parts to 2 parts, and the imidazole-based curing accelerator (4 parts) was changed. Resin varnish 3 was prepared in the same manner as resin varnish 2 except that the blending amount of 1-benzyl-2-phenylimidazole (1B2PZ) and MEK solution having a solid content of 5% by mass was changed from 3 parts to 1 part.

(Preparation of resin varnish 4)
Bisphenol type epoxy resin ("ZX1059" manufactured by Nippon Steel & Sumitomo Metal Corporation, epoxy equivalent about 169, 1: 1 mixture of bisphenol A type and bisphenol F type), 5 parts, naphthalene type epoxy resin ("HP4032SS" manufactured by DIC Co., Ltd.) , Epoxy equivalent about 144) 5 parts, Naphthalene type epoxy resin ("HP-4710" manufactured by DIC Co., Ltd., Epoxy equivalent about 170) 5 parts, Vixilenol type epoxy resin ("YX4000HK" manufactured by Mitsubishi Chemical Co., Ltd. ", Epoxy equivalent about 185) 5 parts, biphenyl type epoxy resin ("NC3000H" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 288) 12 parts, and phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, solid content 30% by mass) 10 parts of cyclohexanone: a 1: 1 solution of methyl ethyl ketone (MEK)) was heated and dissolved in a mixed solvent of 20 parts of solvent naphtha and 10 parts of cyclohexanone with stirring. After cooling to room temperature, there are 12 parts of a triazine skeleton-containing phenol novolac-based curing agent (hydroxyl equivalent 125, "LA7054" manufactured by DIC Co., Ltd., MEK solution having a solid content of 60%), and a naphthol-based curing agent (DIC (DIC). "EXB-9500" manufactured by Co., Ltd., 12 parts of MEK solution with a hydroxyl group equivalent of 190 and a solid content of 50%, 1 part of an amine-based curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with a solid content of 5% by mass) , Flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanslen-10-oxide, average particle size 2 μm ) 2 parts, 2 parts of rubber particles ("AC3816N" manufactured by Aika Kogyo Co., Ltd.) are inflated to 10 parts of MEK at room temperature for 12 hours, aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Industry Co., Ltd. ) Surface-treated spherical silica (“SOC4” manufactured by Admatex Co., Ltd., average particle size 1 μm, carbon content per unit surface area 0.31 mg / m ² ) 200 parts) are mixed and uniformly dispersed with a high-speed rotary mixer. After that, the resin varnish 4 was prepared by filtering with a cartridge filter (“SHP050” manufactured by ROKITECHNO).

(Preparation of resin varnish 5)
Bisphenol type epoxy resin ("ZX1059" manufactured by Nippon Steel & Sumitomo Metal Corporation, epoxy equivalent about 169, 1: 1 mixture of bisphenol A type and bisphenol F type), 5 parts, bisphenol AF type epoxy resin (manufactured by Mitsubishi Chemical Corporation) "YL7760", epoxy equivalent 238) 10 parts, bisphenol type epoxy resin (Mitsubishi Chemical Co., Ltd. "YX4000HK", epoxy equivalent about 185) 5 parts, naphthalene type epoxy resin (Nittetsu Sumikin Chemical Co., Ltd. "ESN475V" , Epoxy equivalent 330) 20 parts, and phenoxy resin (“YX7553BH30” manufactured by Mitsubishi Chemical Corporation, cyclohexanone with a solid content of 30% by mass: 1: 1 solution of methyl ethyl ketone (MEK)), 30 parts of solventnaphtha and 5 parts of cyclohexanone. It was dissolved by heating in the mixed solvent of the part with stirring. After cooling to room temperature, 12 parts of a triazine skeleton-containing cresol novolac-based curing agent (hydroxyl equivalent 151, "LA-3018-50P" manufactured by DIC Co., Ltd., 2-methoxypropanol solution having a solid content of 50%), 12 parts of active ester-based curing agent (“HPC-8000-65T” manufactured by DIC Co., Ltd., active group equivalent of about 223, toluene solution of 65% by mass of non-volatile component), amine-based curing accelerator (4-dimethylaminopyridine (DMAP)) ), 1.5 parts of MEK solution with a solid content of 5% by mass, 1 part of an imidazole-based curing accelerator (1-benzyl-2-phenylimidazole (1B2PZ), MEK solution with a solid content of 5% by mass), a flame retardant (Sanko) "HCA-HQ" manufactured by HCA-HQ Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm) 2 parts, aminosilane Spherical silica surface-treated with a system-based coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Industry Co., Ltd.) (“SOC1” manufactured by Admatex Co., Ltd., average particle size 0.25 μm, carbon content per unit surface surface 0.36 mg / ^{M 2} ) 160 parts were mixed and uniformly dispersed with a high-speed rotary mixer, and then filtered with a cartridge filter (“SHP030” manufactured by ROKICHNO) to prepare a resin varnish 5.

(Preparation of resin varnish 6)
In the preparation of the resin varnish 1, the same as the resin varnish 1 except that a mixed solvent of 15 parts of solvent naphtha, 15 parts of MEK and 15 parts of cyclohexanone was used instead of the mixed solvent of 15 parts of solvent naphtha and 5 parts of cyclohexanone. Resin varnish 6 was prepared.

(Measurement of viscosity of resin varnish)
The viscosity was measured using a rotary (E-type) viscometer (Toki Sangyo Co., Ltd. "RE-80U") equipped with a cone plate having a radius of 24 mm and an angle of 1.34 °. On a sample table in which temperature-controlled water at 25 ° C was circulated in a jacket, 1.2 g of sample resin composition varnish was collected so as not to contain air bubbles, allowed to stand for 2 minutes, temperature-controlled, and then rotated at a rotation speed of 20 rpm for 2 minutes. The value at the time of allowing was taken as the viscosity.

(Example 1: Preparation of resin sheet 1)
As a support, a PET film ("Lumilar T6AM" manufactured by Toray Industries, Inc., thickness 38 μm, softening point 130 ° C.) that has been mold-released with an alkyd resin-based mold release agent ("AL-5" manufactured by Lintec Co., Ltd.) is used. I prepared it.
The resin sheet 1 was produced by the simultaneous coating method according to the following procedure. A roll-shaped PET film is installed in the coating machine, unwound, and the resin varnish 1 is applied to the release surface of the support using a two-layer slit die coater, and at the same time, the resin varnish is applied onto the resin varnish 1. 4 was applied. The resin varnish 1 was applied and coated (coated) so that the target thickness after drying was 5 μm, and the resin varnish 4 was applied and applied so that the target thickness after drying was 20 μm. Each resin composition layer was formed by drying at 70 ° C. to 110 ° C. (average 95 ° C.) for 4.5 minutes. Next, a polypropylene film (“Alfan MA-411” manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) was applied as a protective film on the surface of the resin composition layer that was not bonded to the support, and the rough surface of the protective film was applied. Was laminated so as to be bonded to the second resin composition layer. As a result, a resin sheet 1 composed of a support, a first resin composition layer (derived from resin varnish 1), a mixed layer, a second resin composition layer (derived from resin varnish 4), and a protective film was obtained. .. The target thickness after the resin varnish is applied and dried means the thickness when the resin varnish is applied and dried as it is.

(Example 2: Preparation of resin sheet 2)
The resin sheet 2 was produced in the same manner as in Example 1 except that the tandem coating method was used instead of the simultaneous coating method. Specifically, the resin varnish 1 is applied to 3 μm using a die coater, applied so as to have the target thickness after drying, and pre-dried at 90 ° C. for 0.8 minutes (residual solvent amount of about 30% by mass). , Apply 22 μm of resin varnish 4 on the resin varnish 1 using a die coater, apply it to the target thickness after drying, and dry it at 80 ° C to 110 ° C (average 100 ° C) for 4 minutes. Obtained a resin sheet 2 in the same manner as in Example 1.

(Example 3: Preparation of resin sheet 3)
In Example 1, the resin sheet 3 was obtained in the same manner as in Example 1 except that the resin varnish 2 was used instead of the resin varnish 1 and the resin varnish 5 was used instead of the resin varnish 4.

(Example 4: Preparation of resin sheet 4)
In Example 1, 1) a resin varnish 3 was used instead of the resin varnish 1, and the target thickness after application and drying of the resin varnish was changed from 5 μm to 8 μm. 2) The resin varnish 5 was used instead of the resin varnish 4. A resin sheet 4 was obtained in the same manner as in Example 1 except that the target thickness after coating and drying the resin varnish was changed from 20 μm to 17 μm.

(Comparative Example 1: Fabrication of Resin Sheet 5)
As a support, a PET film ("Lumilar T6AM" manufactured by Toray Industries, Inc., thickness 38 μm, softening point 130 ° C.) that has been mold-released with an alkyd resin-based mold release agent ("AL-5" manufactured by Lintec Co., Ltd.) is used. I prepared it.
The resin sheet 5 was produced by the following procedure by the double coating method. Apply the resin varnish 1 on the support using a die coater, apply it so that the target thickness after drying is 3 μm, and dry it at 70 ° C to 110 ° C (average 95 ° C) for 4.5 minutes. The first resin composition layer was formed. Next, the resin varnish 4 is applied onto the first resin composition layer using a die coater, and the resin varnish 4 is applied so that the target thickness after drying is 22 μm, and the temperature is 70 ° C to 110 ° C (average 95 ° C). The mixture was dried for 4.5 minutes to form a second resin composition layer, and a resin sheet 5 was obtained.

(Comparative Example 2: Fabrication of Resin Sheet 6)
In Example 1, 1) a resin varnish 6 was used instead of the resin varnish 1, and the target thickness after application and drying of the resin varnish was changed from 5 μm to 3 μm. 2) After application and drying of the resin varnish 4. A resin sheet 6 was obtained in the same manner as in Example 1 except that the target thickness was changed from 20 μm to 22 μm.

(Measurement of minimum melt viscosity)
The first or second resin composition layer was coated on the PET film with a single layer under the same conditions as in each example and each comparative example, and a measurement sample was prepared. Using a dynamic viscous modulus measuring device (“Rheosol-G3000” manufactured by UBM Co., Ltd.), a starting temperature of 60 ° C. to 200 ° C. was used for 1 g of the sample resin composition using a parallel plate having a diameter of 18 mm. The temperature was raised to 5 ° C / min, the dynamic viscous 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 minimum melt viscosity (poise) was measured. bottom.

(Measurement of thickness of each layer of resin sheet)
The protective film was peeled off from the resin sheet (200 mm square) produced in each Example and each Comparative Example. With the second resin composition layer as the upper surface, the resin sheet is placed on a glass cloth base material epoxy resin double-sided copper-clad laminate (0.7 mm thick, "R5715ES" manufactured by Matsushita Electric Works Co., Ltd.) having a size of 255 mm x 255 mm. Then, fix the four sides of the resin sheet with polyimide adhesive tape (width 10 mm), and keep it at 100 ° C (after putting it in the oven at 100 ° C) for 30 minutes, and then at 175 ° C (after transferring it to the oven at 175 ° C) for 30 minutes. , Heat cured. Then, the substrate was taken out in a room temperature atmosphere.

The thermosetting resin sheet was cross-sectionally observed using a FIB-SEM composite device (“SMI3050SE” manufactured by SII Nanotechnology Co., Ltd.). Specifically, the cross section in the direction perpendicular to the surface of the resin sheet was cut out by FIB (focused ion beam), and a cross section SEM image (observation width 30 μm, observation magnification 9,000 times) was obtained. For each sample, five randomly selected cross-sectional SEM images were obtained, the thickness of each layer was shown as an average value, and this value was taken as the thickness of each layer.

(Manufacturing and evaluation of printed wiring boards)
Using the resin sheets of each Example and each Comparative Example, a printed wiring board was produced according to the following procedure.

<Manufacturing of printed wiring board>
(1) Substrate treatment of circuit board Glass cloth base material Epoxy resin Double-sided copper-clad laminate (copper foil thickness 18 μm, substrate thickness 0.3 mm, Hitachi Kasei Kogyo Co., Ltd. “679FGR”) IPC MULTI-PURPOSE TEST BOARD NO. An IPC B-25 pattern (line / space = 175/175 μm comb tooth pattern (residual copper ratio 50%)) is formed, and both sides are etched by 1 μm with a micro-etching agent (“CZ8100” manufactured by MEC Co., Ltd.). The copper surface was roughened.

(2) Laminating of resin sheets The protective film was peeled off from the resin sheets produced in Examples and Comparative Examples. Using a batch type vacuum pressurizing laminator (2-stage build-up laminator "CVP700" manufactured by Nichigo Morton Co., Ltd.), the resin sheet was attached to the circuit board so that the second resin composition layer was bonded to the circuit board. Laminated on both sides. Lamination was carried out by reducing the pressure for 30 seconds to reduce the atmospheric pressure to 13 hPa or less, and then crimping at 110 ° C. and a pressure of 0.74 MPa for 30 seconds. Next, the laminated resin sheet was heat-pressed at 110 ° C. and a pressure of 0.5 MPa for 60 seconds under atmospheric pressure to smooth it.

(3) Curing of the resin composition layer After laminating the resin sheet, with the support attached, transfer to an oven at 100 ° C. (after putting in an oven at 100 ° C.) for 30 minutes, and then at 175 ° C. (to an oven at 175 ° C.). After that, it was heat-cured under the condition of 30 minutes to form insulating layers on both sides of the circuit board. Then, the substrate was taken out in a room temperature atmosphere.

(4) Roughening treatment The substrate from which the support has been peeled off is placed in a swelling solution (an aqueous solution containing "Swelling Dip Securigant P" manufactured by Atotech Japan Co., Ltd., diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 5 minutes. (Examples 1 and 2 and Comparative Examples 1 and 2) or 10 minutes (Examples 3 and 4), oxidizing agent ("Concentrate Compact CP" manufactured by Atotech Japan Co., Ltd., KMnO ₄ : 60 g / L, NaOH: Soak in a 40 g / L aqueous solution at 80 ° C for 20 minutes, and finally in a neutralizing solution (“Reduction Solution Securigant P” manufactured by Atotech Japan Co., Ltd., sulfuric acid aqueous solution) at 40 ° C for 5 minutes, and then at 80 ° C. It was dried for 30 minutes. The obtained substrate is referred to as "evaluation substrate A".

(5) Formation of Conductor Layer by Semi-Additive Method The evaluation substrate A was _{immersed in an electroless plating solution containing PdCl 2} at 40 ° C. for 5 minutes, and then immersed in an electroless copper plating solution at 25 ° C. for 20 minutes. The obtained substrate was heated at 150 ° C. for 30 minutes to be annealed, and then electrolytically plated with copper sulfate to form a conductor layer having a thickness of 30 μm on the entire surface. Then, it was heated at 190 ° C. for 60 minutes to perform annealing treatment. The obtained substrate is referred to as "evaluation substrate B".

<Evaluation>
(1) Arithmetic mean roughness (Ra)
The arithmetic mean roughness (Ra) of the surface of the insulating layer was measured and evaluated by the following procedure. For each evaluation substrate A, a non-contact type surface roughness meter (“WYKO NT3300” manufactured by Becoin Sturments) was used on the surface of the insulating layer on a comb tooth pattern (residual copper ratio 50%) with line / space = 175/175 μm. Using the VSI contact mode, the measurement range was set to 121 μm × 92 μm with a 50x lens, and the Ra value was determined from the obtained numerical values. Ra values were calculated for 10 randomly selected points. Then, the value of the difference between the maximum value and the minimum value (maximum value-minimum value) of the Ra value was evaluated according to the following criteria.
[Evaluation criteria]
◯: Difference is 150 nm or less ×: Difference is more than 150 nm

(2) Peel strength The peel strength between the insulating layer and the conductor layer was measured and evaluated by the following procedure. For each evaluation board B, make a notch in a portion having a width of 10 mm and a length of 100 mm in a conductor layer on a comb tooth pattern (residual copper ratio of 50%) with a line / space = 175/175 μm, and peel off one end of the cut tool. (TSE Co., Ltd., Autocom type tester "AC-50C-SL") Grasp and load (kgf /) when 35 mm is peeled off vertically at a speed of 50 mm / min at room temperature. cm) was measured. Then, the value of the difference (maximum value-minimum value) between the maximum value and the minimum value of the peel strength was evaluated according to the following criteria.
[Evaluation criteria]
◯: Difference is 0.15 kgf / cm or less ×: Difference is more than 0.15 kgf / cm

(3) The reflow resistance evaluation substrate B was cut into pieces of 45 mm square (n = 3), and then left to stand in an atmosphere of 60 ° C. and 60% relative humidity for 48 hours. After that, it was passed through a reflow device (“HAS-6116” manufactured by Nippon Antom Co., Ltd.) that reproduces the solder reflow temperature with a peak temperature of 260 ° C. (the reflow temperature profile conforms to IPC / JEDEC J-STD-020C). The reflow step was performed up to 13 times, and the presence or absence of peeling abnormality such as delamination in the insulating layer and peeling between the insulating layer and the conductor layer, and the timing of the peeling abnormality were evaluated according to the following criteria.
[Evaluation criteria]
⊚: No peeling abnormality up to 13 times ○: Peeling abnormality occurred even with 1 piece in 7 to 12 times ×: Peeling abnormality occurred even with 1 piece by 6th time

From the above table, it can be seen that Examples 1 to 4 have high stability of roughness and peel strength, suppress delamination even when exposed to a high temperature environment during reflow, and have excellent reflow resistance. The resin sheets of Examples 1 and 3 having a thickness of the mixed layer of 1.0 μm or more are superior in reflow resistance to the resin sheet of Example 2 having a thickness of the mixed layer of 0.7 μm. It turns out that it brings. Further, the resin sheets of Examples 1 and 3 in which the minimum melt viscosity of the first resin composition layer is 5000 poses or more are the resins of Example 4 in which the minimum melt viscosity of the first resin composition layer is 3900 poses. It can be seen that it provides a better insulating layer with better reflow resistance compared to the sheet.
On the other hand, in the resin sheet of Comparative Example 1 produced by the double coating method, the thickness of the mixed layer is thin, and the insulating layer formed by using the resin sheet causes delamination in a high temperature environment during reflow. It is easy to see that it is inferior in reflow resistance.
Further, in Comparative Example 2 in which the first resin composition layer was prepared using the resin varnish having a viscosity of 80 mPa · s, the surface of the insulating layer obtained due to the repelling of the resin varnish on the support and the like. It can be seen that the number of defects increases and the stability of roughness and peel strength is inferior. In Comparative Example 2, the stability of the roughness and the peel strength is also combined with the fact that the resin varnishes are excessively mixed with each other due to the low viscosity resin varnish and the thickness of the first resin composition layer is thin. Will be inferior. In places where the peel strength is low, peeling between the insulating layer and the conductor layer also occurs, so that the reflow resistance is significantly inferior.

1 Resin sheet 11 Support 12 First resin composition layer 13 Mixed layer 14 Second resin composition layer 100 Resin sheet manufacturing equipment 101 Coating equipment 102 Drying equipment 200 Resin sheet manufacturing equipment 201 First coating equipment 202 Pre-drying device 203 Second coating device 204 Drying device

Claims (18)

A second resin composition layer composed of a support, a first resin composition provided on the support, and a second resin composition provided on the first resin composition layer. A mixed layer in which the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. It is a manufacturing method of a resin sheet having
The first resin composition and the second resin composition contain an epoxy resin, and the first resin composition and the second resin composition contain an epoxy resin.
The first resin composition contains a solid epoxy resin, and the content of the solid epoxy resin is 30% by mass or more when the non-volatile component of the entire epoxy resin contained in the first resin composition is 100% by mass. And
The content of the epoxy resin in the first resin composition is 5% by mass or more and 50% by mass or less when the total of the non-volatile components in the first resin composition is 100% by mass.
The content of the epoxy resin in the second resin composition is 3% by mass or more and 45 % by mass or less when the total of the non-volatile components in the second resin composition is 100% by mass.
The first and second resin compositions contain a curing agent, and the content of the curing agent is 3% by mass or more and 30% by mass or less when the total of the non-volatile components in the resin composition is 100% by mass.
The first resin composition contains an inorganic filler, and the content of the inorganic filler is 60% by mass or less when the total of the non-volatile components in the first resin composition is 100% by mass.
The second resin composition contains an inorganic filler, and the content of the inorganic filler is 50% by mass or more when the total of the non-volatile components in the second resin composition is 100% by mass.
A first resin varnish in which the first resin composition is dissolved is applied onto the support, and a second resin varnish in which the second resin composition is dissolved is applied onto the first resin varnish and dried. Including the process of
The viscosity of the first resin varnish is 100 mPa · s or more,
A method for producing a resin sheet, wherein the viscosity of the second resin varnish is 100 mPa · s or more. A step of applying the first resin varnish on the support and at the same time applying the second resin varnish on the first resin varnish and then drying is included, or
The resin according to claim 1, further comprising a step of applying a first resin varnish on a support, pre-drying it, then applying a second resin varnish on the first resin varnish, and then drying it. How to make a sheet. Claimed that the amount of residual solvent in the first resin varnish after pre-drying is 15% by mass to 70% by mass when the total of the non-volatile components contained in the first resin varnish is 100% by mass. Item 2. The method for manufacturing a resin sheet according to Item 2. The method for producing a resin sheet according to claim 1 or 2, which comprises a step of applying a first resin varnish on a support and at the same time applying a second resin varnish on the first resin varnish and then drying. .. When the thickness of the first resin composition layer is 0.3 μm to 15 μm, the thickness of the second resin composition layer is 3 μm to 200 μm, and the thickness of the mixed layer is 0.4 μm or more, the first resin composition The method for producing a resin sheet according to any one of claims 1 to 4, which is not more than twice the thickness of the layer. The method for producing a resin sheet according to any one of claims 1 to 5, wherein the support is a support with a release layer. The resin sheet according to any one of claims 1 to 6, wherein the minimum melt viscosity of the first resin composition layer is 3000 poise or more, and the minimum melt viscosity of the second resin composition layer is 10,000 poise or less. Production method. The resin according to any one of claims 1 to 7, wherein the viscosity of the first resin varnish is 100 mPa · s to 3000 mPa · s, and the viscosity of the second resin varnish is 100 mPa · s to 6000 mPa · s. How to make a sheet. The method for producing a resin sheet according to any one of claims 1 to 8, wherein the first resin varnish and the second resin varnish are applied on the same coating line. A method for manufacturing a printed wiring board, wherein a resin sheet manufactured by the method according to any one of claims 1 to 9 is laminated on an inner layer substrate, heat-cured, and then the support is removed. The amount ratio of the epoxy resin to the curing agent in the first and second resin compositions ([total number of epoxy groups in the epoxy resin]: [total number of reactive groups in the curing agent]) is 1: 0.2. The method for manufacturing a printed wiring board according to any one of claims 1 to 10, which is ~ 1: 2. A second resin composition layer composed of a support, a first resin composition provided on the support, and a second resin composition provided on the first resin composition layer. A mixed layer in which the first resin composition and the second resin composition are mixed between the first resin composition layer and the second resin composition layer. Have,
The first resin composition and the second resin composition contain an epoxy resin, and the first resin composition and the second resin composition contain an epoxy resin.
The first resin composition contains a solid epoxy resin, and the content of the solid epoxy resin is 30% by mass or more when the non-volatile component of the entire epoxy resin contained in the first resin composition is 100% by mass. And
The content of the epoxy resin in the first resin composition is 5% by mass or more and 50% by mass or less when the total of the non-volatile components in the first resin composition is 100% by mass.
The content of the epoxy resin in the second resin composition is 3% by mass or more and 45 % by mass or less when the total of the non-volatile components in the second resin composition is 100% by mass.
The first and second resin compositions contain a curing agent, and the content of the curing agent is 3% by mass or more and 30% by mass or less when the total of the non-volatile components in the resin composition is 100% by mass.
The first resin composition contains an inorganic filler, and the content of the inorganic filler is 60% by mass or less when the total of the non-volatile components in the first resin composition is 100% by mass.
The second resin composition contains an inorganic filler, and the content of the inorganic filler is 50% by mass or more when the total of the non-volatile components in the second resin composition is 100% by mass.
A resin sheet having a thickness of the mixed layer of 0.4 μm or more. When the thickness of the first resin composition layer is 0.3 μm to 15 μm, the thickness of the second resin composition layer is 3 μm to 200 μm, and the thickness of the mixed layer is 0.4 μm or more, the first resin composition The resin sheet according to claim 12, which is not more than twice the thickness of the layer. The resin sheet according to claim 12 or 13, wherein the minimum melt viscosity of the first resin composition layer is 3000 poise or more. The resin sheet according to any one of claims 12 to 14, wherein the minimum melt viscosity of the second resin composition layer is 10,000 poise or less. The amount ratio of the epoxy resin to the curing agent in the first and second resin compositions ([total number of epoxy groups in the epoxy resin]: [total number of reactive groups in the curing agent]) is 1: 0.2. The resin sheet according to any one of claims 12 to 15, which is ~ 1: 2. A printed wiring board including an insulating layer formed by using the resin sheet according to any one of claims 12 to 16. A semiconductor device including the printed wiring board according to claim 17.

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