JP7447632B2 - Manufacturing method of printed wiring board - Google Patents

Description

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

Printed wiring boards are widely used in various electronic devices. Printed wiring boards are required to have finer circuit wiring and higher density in order to make electronic devices smaller and more functional. Here, as a method for manufacturing a printed wiring board, a manufacturing method using a build-up method in which insulating layers and conductive layers are alternately stacked on an inner layer substrate is known. The insulating layer is formed, for example, by forming a resin composition layer containing a resin composition on the inner layer substrate and thermally curing the resin composition layer on the inner layer substrate.

Further, the method for manufacturing a printed wiring board may include a step of drilling holes in the formed insulating layer. As a result of the drilling process, a via hole is formed in the insulating layer, and the conductor layer on the surface of the inner layer substrate is exposed. When forming a via hole, a desmear process is usually performed to remove resin residue (smear) on the via hole wall surface and via hole bottom surface (i.e., the exposed surface of the conductor layer) (for example, Patent Document 1) . Note that the surface of the insulating layer may be roughened simultaneously with the removal of the smear.

Japanese Patent Application Publication No. 2008-037957

By the way, the process of performing desmear treatment (hereinafter also referred to as "desmear process") includes a process of treating the insulating layer with a swelling liquid (hereinafter also referred to as "swelling process"), a process of treating the insulating layer with an oxidizing agent solution ( The method may include, in this order, a step (hereinafter also referred to as "oxidation step") and a step of treating the insulating layer with a neutralizing liquid (hereinafter also referred to as "neutralization step"). The desmear process may further include a process of cleaning the surface of the insulating layer after the swelling process and before the oxidation process, or a process of neutralizing the insulating layer after the oxidation process, as necessary. The method may include a step of cleaning the surface of the insulating layer before performing the step.

Here, a phenomenon called haloing may be observed after the desmear process is performed. Haloing is a phenomenon in which peeling occurs between an inner substrate and an insulating layer around a via hole. Therefore, when haloing occurs, a region where a gap occurs at the interface between the insulating layer and the conductor layer near the bottom of the via hole (i.e., a region where the insulating layer has peeled off from the conductor layer; hereinafter also referred to as the "harrowing region") ) occurs. If the insulating layer is transparent, this haloing region can be seen by observing the top of the insulating layer.

If haloing occurs, there is concern that cracks may occur in the insulating layer and conductive layer due to the haloing, or that chemicals (e.g. plating liquid) or foreign matter may seep into the haloing area. As a result, it may not be possible to achieve finer circuit wiring and higher density on printed wiring boards. Therefore, even if a haloing region occurs, it is required to narrow it.

An object of the present invention is to provide a method for manufacturing a printed wiring board that can realize narrowing of a haloing region near a via hole.

As a result of intensive studies to solve the above problems, the present inventor has discovered that a desmear process performed on a laminate including an inner layer substrate prepared in advance and an insulating layer formed on the inner layer substrate is a swelling process. (Step (B)), oxidation step (Step (C)), and neutralization step (Step (D)) in this order, after the swelling step and before the oxidation step, and Alternatively, after the oxidation step and before the neutralization step, (F) the step of treating the insulating layer with an aqueous liquid at a temperature of 35° C. or higher is performed to narrow the haloing region. The inventors have discovered that this can be realized, and have completed the present invention.

That is, the present invention includes the following contents.
[1] (A) Step of preparing a laminate including an inner layer substrate and an insulating layer formed on the inner layer substrate, (B) Step of drilling holes in the insulating layer, (C) Treating the insulating layer with a swelling liquid (D) treating the insulating layer with an oxidizing solution; and (E) treating the insulating layer with a neutralizing liquid, in this order, the method further comprising: , (F) treating the insulating layer with an aqueous liquid at a temperature of 35° C. or higher; , a method for manufacturing a printed wiring board, which is carried out after performing the step (D) and before performing the step (E).
[2] The method for manufacturing a printed wiring board according to [1], wherein the step (F) includes a step of immersing the insulating layer in an aqueous liquid.
[3] The method for producing a printed wiring board according to [1] or [2], wherein the temperature of the aqueous liquid used in the step (F) is 40°C or higher and 100°C or lower.
[4] The method for manufacturing a printed wiring board according to [3], wherein the temperature of the aqueous liquid used in step (F) is 50° C. or higher.
[5] The step (A) includes a step of forming a resin composition layer containing a resin composition on the inner layer substrate, and a step of thermosetting the resin composition layer on the inner layer substrate, [1] The method for producing a printed wiring board according to any one of [4] to [4].
[6] (A) step is a step of preparing a resin sheet including a support and a resin composition layer provided on the support and containing a resin composition, and the resin composition layer is bonded to the inner layer substrate. The production of the printed wiring board according to any one of [1] to [5], including the steps of: laminating a resin sheet on the inner layer substrate so as to make the resin composition layer on the inner layer substrate, and thermosetting the resin composition layer on the inner layer substrate. Method.
[7] The method for manufacturing a printed wiring board according to [5] or [6], wherein the resin composition contains a phenolic curing agent.
[8] The method for producing a printed wiring board according to any one of [5] to [7], wherein the resin composition contains an active ester curing agent.
[9] The method for producing a printed wiring board according to any one of [5] to [8], wherein the maximum thickness of the resin composition layer is 100 μm.
[10] The method for producing a printed wiring board according to any one of [1] to [9], wherein the aqueous liquid is water.
[11] The method for manufacturing a printed wiring board according to any one of [1] to [10], further comprising the step of (G) washing the surface of the insulating layer with water at a temperature below 35°C.

According to the present invention, it is possible to provide a method for manufacturing a printed wiring board that can realize narrowing of the haloing area.

FIG. 1 is a partially enlarged sectional view of an example of a laminate. FIG. 2 is a partially enlarged top view of the laminate in which the insulating layer has been drilled, when viewed from the insulating layer side. FIG. 3 is a partially enlarged sectional view schematically showing a cross section of the laminate taken along line III-III in FIG.

Before explaining in detail the method for manufacturing a printed wiring board of the present invention, a resin composition that can be used as a forming material for an insulating layer included in a printed wiring board manufactured by the method for manufacturing a printed wiring board of the present invention will be described.

[Resin composition]
In one embodiment, the resin composition includes (a) a thermosetting resin and (b) a curing agent. Component (b) has the function of curing component (a). However, those that fall under component (b) are excluded from component (a). In another embodiment, the resin composition includes (a) a thermosetting resin, (b) a curing agent, and (c) an inorganic filler. The resin composition according to each embodiment may further contain (d) a thermoplastic resin, (e) a curing accelerator, and (f) other It may also contain additives. Each component contained in the resin composition will be explained in detail below.

-(a) Thermosetting resin-
In one embodiment, the resin composition contains (a) a thermosetting resin as the (a) component. As the thermosetting resin, a thermosetting resin that can be used as an insulating member such as an insulating layer can be used. Examples of such thermosetting resins include epoxy resins, phenol resins, naphthol resins, benzoxazine resins, cyanate ester resins, carbodiimide resins, amine resins, and acid anhydride resins. . The thermosetting resin preferably includes an epoxy resin. Component (a) may be used alone or in combination of two or more.

Examples of the epoxy resin as component (a) include bixylenol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, Trisphenol type epoxy resin, naphthol novolac type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin with butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiro ring-containing epoxy resin, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, tetraphenylethane type epoxy resin and the like. One type of epoxy resin may be used alone, or two or more types may be used in combination.

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

Epoxy resins include epoxy resins that are liquid at a temperature of 20°C (hereinafter sometimes referred to as "liquid epoxy resins") and epoxy resins that are solid at a temperature of 20°C (hereinafter sometimes referred to as "solid epoxy resins"). ). The resin composition may contain only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin as component (a). good. Component (a) is a liquid epoxy resin and a solid epoxy resin, from the viewpoint of obtaining sufficient flexibility when used in the form of a resin sheet and improving the breaking strength of the cured product of the resin composition layer. It is preferable to use it in combination with resin.

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

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

Specific examples of solid epoxy resins include "HP4032H" (naphthalene type epoxy resin) manufactured by DIC; "HP-4700" and "HP-4710" (naphthalene type tetrafunctional epoxy resin) manufactured by DIC; “N-690” (cresol novolak type epoxy resin) manufactured by DIC; “N-695” (cresol novolac type epoxy resin) manufactured by DIC; “HP-7200”, “HP-7200HH”, “HP” manufactured by DIC -7200H" (dicyclopentadiene type epoxy resin); DIC's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" ( naphthylene ether type epoxy resin); "EPPN-502H" (trisphenol type epoxy resin) manufactured by Nippon Kayaku; "NC7000L" (naphthol novolac type epoxy resin) manufactured by Nippon Kayaku; "NC3000H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical &Materials; "ESN485" manufactured by Nippon Steel Chemical & Materials ” (naphthol novolac type epoxy resin); “YX4000H”, “YX4000”, “YL6121” manufactured by Mitsubishi Chemical (biphenyl type epoxy resin); “YX4000HK” manufactured by Mitsubishi Chemical (bixylenol type epoxy resin); Mitsubishi Chemical "YX8800" (anthracene type epoxy resin) manufactured by Osaka Gas Chemical Company; "PG-100", "CG-500" manufactured by Osaka Gas Chemical Company; "YL7760" (bisphenol AF type epoxy resin) manufactured by Mitsubishi Chemical Company; "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical; "jER1010" (solid bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical; "jER1031S" (tetraphenylethane type epoxy resin) manufactured by Mitsubishi Chemical. . These may be used alone or in combination of two or more.

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

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

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

When using a combination of liquid epoxy resin and solid epoxy resin as component (a), their quantitative ratio (liquid epoxy resin: solid epoxy resin) is preferably 10:1 to 1:20 in terms of mass ratio, The ratio is more preferably 5:1 to 1:15, particularly preferably 1:1 to 1:10. When the ratio of the liquid epoxy resin to the solid epoxy resin is within this range, the desired effects of the present invention can be significantly obtained.

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

The weight average molecular weight (Mw) of the epoxy resin as component (a) is preferably from 100 to 5,000, more preferably from 250 to 3,000, still more preferably from 400 to 1,500, from the viewpoint of significantly obtaining the desired effects of the present invention. It is.
The weight average molecular weight of the resin can be measured as a value in terms of polystyrene by gel permeation chromatography (GPC).

From the viewpoint of obtaining an insulating layer exhibiting good mechanical strength and insulation reliability, the content of the epoxy resin as component (a) is preferably 1% by mass when the nonvolatile components in the resin composition are 100% by mass. The content is more preferably 3% by mass or more, still more preferably 5% by mass or more. The upper limit of the content of the epoxy resin is preferably 45% by mass or less, more preferably 40% by mass or less, particularly preferably 35% by mass or less, from the viewpoint of significantly obtaining the intended effects of the present invention.

When the resin composition contains an epoxy resin as the component (a) and a curing agent (b), the ratio of the amount of the epoxy resin to all the curing agents (b) is [total number of epoxy groups in the epoxy resin] ]:[Total number of reactive groups of (b) curing agent] The ratio is preferably in the range of 1:0.01 to 1:5, more preferably 1:0.5 to 1:3, and 1:1 to 1:2 is more preferred. Here, "the number of epoxy groups in the epoxy resin" is the sum of all the values obtained by dividing the mass of nonvolatile components of the epoxy resin present in the resin composition by the epoxy equivalent. Moreover, "the number of active groups of the (b) curing agent" is the total value of all the values obtained by dividing the mass of the nonvolatile components of the curing agent (b) present in the resin composition by the active group equivalent. By setting the ratio of the epoxy resin to the curing agent (b) within this range, it becomes possible to significantly obtain the effects of the present invention.

From the viewpoint of significantly obtaining the effects of the present invention, the content of component (a) is preferably 3% by mass or more, more preferably 5% by mass or more, based on 100% by mass of nonvolatile components in the resin composition. The content is preferably 10% by mass or more, preferably 45% by mass or less, more preferably 40% by mass or less, particularly preferably 35% by mass or less.

-(b) Hardening agent-
The curing agent is not particularly limited as long as it has the function of curing the thermosetting resin, but examples include phenol curing agents, naphthol curing agents, active ester curing agents, benzoxazine curing agents, and cyanate ester curing agents. Examples include agents. One type of curing agent may be used alone, or two or more types may be used in combination. Among these, from the viewpoint of suppressing the occurrence of haloing, it is preferable that component (b) contains a phenolic curing agent. From the viewpoint of realizing an insulating layer with low roughness and high adhesion strength to the conductor layer while maintaining the pot life of the composition, component (b) is one selected from phenolic curing agents and naphthol curing agents. It is preferable that the above curing agent is included.

As the phenol curing agent and the naphthol curing agent, from the viewpoint of heat resistance and water resistance, a phenol curing agent having a novolak structure or a naphthol curing agent having a novolak structure is preferable. Further, from the viewpoint of adhesion strength with the conductor layer, a nitrogen-containing phenolic curing agent is preferable, and a triazine skeleton-containing phenolic curing agent is more preferable. Among these, it is preferable to use a triazine skeleton-containing phenol novolak resin as the curing agent from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion strength with the conductor layer.

Specific examples of phenolic curing agents and naphthol curing agents include "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., "NHN" manufactured by Nippon Kayaku Co., Ltd. "CBN", "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN375", "SN395" manufactured by Toto Kasei Corporation, "SN395" manufactured by DIC Corporation Examples include "LA-7052", "LA-7054", "LA-3018", and "LA-1356".

Specific examples of benzoxazine curing agents include "HFB2006M" manufactured by Showa Kobunshi Co., Ltd., and "Pd" and "Fa" manufactured by Shikoku Kasei Kogyo Co., Ltd.

Examples of the cyanate ester curing agent include bisphenol A dicyanate, polyphenol cyanate (oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4 '-Ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate) phenylpropane, 1,1-bis(4-cyanate phenylmethane), bis(4-cyanate-3,5-dimethyl Bifunctional cyanate resins such as phenyl)methane, 1,3-bis(4-cyanatophenyl-1-(methylethylidene))benzene, bis(4-cyanatophenyl)thioether, and bis(4-cyanatophenyl)ether, phenol Examples include polyfunctional cyanate resins derived from novolak and cresol novolac, prepolymers in which these cyanate resins are partially triazinized, etc. Specific examples of cyanate ester curing agents include "PT30" manufactured by Lonza Japan Co., Ltd. Examples include "PT60" (both are phenol novolac type polyfunctional cyanate ester resins), "BA230" (a prepolymer in which part or all of bisphenol A dicyanate is triazinized to form a trimer), and the like.

Active ester curing agents generally have two or more ester groups with high reaction activity in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. compounds are preferably used. The active ester curing agent is preferably one obtained by a condensation reaction between a carboxylic acid compound and/or a thiocarboxylic acid compound and a hydroxy compound and/or a thiol compound. Particularly from the viewpoint of improving heat resistance, active ester curing agents obtained from a carboxylic acid compound and a hydroxy compound are preferred, and active ester curing agents obtained from a carboxylic acid compound and a phenol compound and/or a naphthol compound are more preferred. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid. Examples of phenolic compounds or naphthol compounds include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalin, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, Examples include benzenetriol, dicyclopentadiene type diphenol compounds, and phenol novolacs. Here, the term "dicyclopentadiene type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol with one molecule of dicyclopentadiene.

Specifically, dicyclopentadiene-type active ester curing agents, active ester curing agents containing a naphthalene structure, active ester curing agents containing an acetylated product of phenol novolak, and active ester curing agents containing a benzoylated product of phenol novolak. are preferable, and among them, active ester curing agents containing a naphthalene structure and dicyclopentadiene type active ester curing agents are more preferable, and dicyclopentadiene type active ester type curing agents are even more preferable. As the dicyclopentadiene type active ester curing agent, an active ester type curing agent containing a dicyclopentadiene type diphenol structure is preferable. "Dicyclopentadiene type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentylene-phenylene.

(b) Commercially available active ester curing agents containing a dicyclopentadiene diphenol structure include "EXB9451" (manufactured by DIC Corporation, active ester group equivalent weight: 223), "EXB9460" (manufactured by DIC Corporation, active ester group equivalent weight: 223), "EXB9460S" (manufactured by DIC, active ester group equivalent: 223), "HPC-8000-65T" (manufactured by DIC, active ester group equivalent: 223), "HPC-8000H-65TM" ” (manufactured by DIC, active ester group equivalent: 224), “HPC8000L-65TM” (manufactured by DIC, active ester group equivalent: 220), “EXB-8100L-65T” (manufactured by DIC, an active ester curing agent containing a naphthalene structure) "EXB8150-60T" (manufactured by DIC, active ester group equivalent: 226), "EXB9416-70BK" (manufactured by DIC, active ester group equivalent: 274), "HPC-8150-60T" (manufactured by DIC), "HPC-8150-62T" (manufactured by DIC), "EXB-8150-65T" (manufactured by DIC), "PC1300-02" (manufactured by Air Water, active ester group equivalent: 200) , "EXB9401" (manufactured by DIC Corporation, active ester group equivalent: 307) as a phosphorus-containing active ester curing agent, "DC808" (manufactured by Mitsubishi Chemical Corporation, active ester group equivalent) as an active ester curing agent that is an acetylated product of phenol novolac. 149), active ester curing agents which are benzoylated products of phenol novolak include "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), "YLH1048" (manufactured by Mitsubishi Chemical Corporation), and the like.

The active ester group equivalent of the active ester curing agent is preferably 50 g/eq. ～500g/eq. , more preferably 50g/eq. ～400g/eq. , more preferably 100g/eq. ～300g/eq. It is. The active ester group equivalent is the mass of an active ester curing agent containing 1 equivalent of active ester groups.

From the viewpoint of obtaining an insulating layer with a low dielectric loss tangent, the curing agent (b) may contain an active ester curing agent. When active ester curing agents are used, haloing tends to occur more easily than when other curing agents, such as phenolic curing agents, are used, but the production method of the present invention Since the haloing region can be narrowed, the active ester curing agent can be included in the resin composition. In this case, the resin composition preferably contains an active ester curing agent and a curing agent other than the active ester curing agent as the (b) component, and more preferably a phenolic curing agent as the (b) component. and active ester-based cured products.

(b) The content of the curing agent is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, when the nonvolatile components in the resin composition are 100% by mass. Further, the upper limit is preferably 30% by mass or less, more preferably 25% by mass or less, still more preferably 20% by mass or less. In the present invention, the content of each component in the resin composition is a value based on 100% by mass of nonvolatile components in the resin composition, unless otherwise specified.

-(c) Inorganic filler-
In one embodiment, the resin composition contains an inorganic filler as component (c). (c) By containing an inorganic filler, a cured product with low water absorption can be obtained.

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

(c) Commercially available inorganic fillers include, for example, "UFP-30" manufactured by Denka; "SP60-05" and "SP507-05" manufactured by Nippon Steel Chemical &Materials; and "SP507-05" manufactured by Admatex. "YC100C", "YA050C", "YA050C-MJE", "YA010C"; "Silfill NSS-3N", "Silfill NSS-4N", "Silfill NSS-5N" manufactured by Tokuyama; "SC2500SQ" manufactured by Admatex , "SO-C4", "SO-C2", "SO-C1", and the like.

(c) The average particle size of the inorganic filler is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, from the viewpoint of significantly obtaining the intended effects of the present invention. , preferably 10 μm or less, more preferably 5 μm or less, even more preferably 2 μm or less.

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

(c) The specific surface area of the inorganic filler is preferably 1 m ² /g or more, more preferably 2 m 2 /g or more, particularly preferably 3 m ² /g or more, from the viewpoint of significantly obtaining the intended effects of the ^present invention. It is. Although there is no particular limit to the upper limit, it is preferably 60 m ² /g or less, 50 m ² /g or less, or 40 m ² /g or less. The specific surface area is determined by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210, manufactured by Mountec) according to the BET method, and then calculating the specific surface area using the BET multi-point method. can get.

(c) The inorganic filler is preferably treated with a surface treatment agent from the viewpoint of improving moisture resistance and dispersibility. Examples of surface treatment agents include fluorine-containing silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, and titanate-based coupling agents. Coupling agents and the like can be mentioned. Moreover, one type of surface treatment agent may be used alone, or two or more types may be used in any combination.

Commercially available surface treatment agents include, for example, "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., "KBM803" (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane) manufactured by Kagaku Kogyo, "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "SZ-31" manufactured by Shin-Etsu Chemical ( hexamethyldisilazane), "KBM103" (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical, "KBM-4803" (long chain epoxy type silane coupling agent) manufactured by Shin-Etsu Chemical, "KBM-" manufactured by Shin-Etsu Chemical 7103'' (3,3,3-trifluoropropyltrimethoxysilane).

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

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

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

(c) From the viewpoint of obtaining a cured product with low water absorption, the content of the inorganic filler is preferably 40% by mass or more, more preferably 45% by mass when the nonvolatile component in the resin composition is 100% by mass. % by mass or more, more preferably 50% by mass or more or more than 50% by mass, particularly preferably 60% by mass or more, and the upper limit is determined depending on the content of other components, but for example, 95% by mass or less, It may be 90% by mass or less or 85% by mass or less.

-(d) Thermoplastic resin-
In each embodiment, the resin composition may contain a thermoplastic resin as the component (d). (d) By containing a thermoplastic resin, it becomes possible to relax the stress of the cured product.

(d) Thermoplastic resins include, for example, phenoxy resin, polycarbonate resin, polyvinyl acetal resin, polyolefin resin, polyimide resin, polyamideimide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyphenylene ether resin, polyether Examples include ether ketone resin and polyester resin. Among these, at least one selected from polyimide resins, polycarbonate resins, and phenoxy resins is preferred from the viewpoint of significantly obtaining the intended effects of the present invention. Further, (D) the thermoplastic resin may be used alone or in combination of two or more types.

As the polyimide resin, a resin having an imide structure can be used. Examples of such resins include linear polyimides obtained by reacting bifunctional hydroxyl group-terminated polybutadiene, diisocyanate compounds, and tetrabasic acid anhydrides (polyimide described in JP-A No. 2006-37083), polysiloxane skeletons, etc. Examples include modified polyimides such as polyimides containing polyimides (polyimides described in JP-A-2002-12667 and JP-A-2000-319386, etc.).

Commercially available polyimide resins can be used. Commercially available products include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nihon Rika Co., Ltd.

As the polycarbonate resin, a resin having a carbonate structure can be used. Examples of such resins include hydroxy group-containing carbonate resins, phenolic hydroxyl group-containing carbonate resins, carboxy group-containing carbonate resins, acid anhydride group-containing carbonate resins, isocyanate group-containing carbonate resins, urethane group-containing carbonate resins, and the like.

Commercially available carbonate resins can be used. Commercially available products include "FPC0220" manufactured by Mitsubishi Gas Chemical Co., Ltd., "T6002" and "T6001" (polycarbonate diol) manufactured by Asahi Kasei Chemicals, and "C-1090", "C-2090", and "C" manufactured by Kuraray Corporation. -3090'' (polycarbonate diol).

Examples of phenoxy resins include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, and terpene. Examples include phenoxy resins having one or more types of skeletons selected from the group consisting of a skeleton and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group.

Specific examples of phenoxy resins include "1256" and "4250" manufactured by Mitsubishi Chemical Corporation (both phenoxy resins containing bisphenol A skeleton); "YX8100" manufactured by Mitsubishi Chemical Corporation (phenoxy resin containing bisphenol S skeleton); “YX6954” (bisphenolacetophenone skeleton-containing phenoxy resin) manufactured by Nippon Steel Chemical &Materials; “FX280” and “FX293” manufactured by Nippon Steel Chemical &Materials; “YL7500BH30”, “YX6954BH30”, “YX7553”, “YX7553BH30” manufactured by Mitsubishi Chemical Corporation ”, “YL7769BH30”, “YL6794”, “YL7213”, “YL7290”, “YL7553BH30”, and “YL7482”.

Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include S-LEC BH series, BX series (eg, BX-5Z), KS series (eg, KS-1), BL series, and BM series manufactured by Sekisui Chemical Co., Ltd.

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

A specific example of the polyether sulfone resin includes "PES5003P" manufactured by Sumitomo Chemical Co., Ltd.

Specific examples of the polyphenylene ether resin include oligophenylene ether styrene resin "OPE-2St 1200" manufactured by Mitsubishi Gas Chemical Co., Ltd.

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

(d) The weight average molecular weight (Mw) of the thermoplastic resin is preferably 8,000 or more, more preferably 10,000 or more, particularly preferably 20,000 or more, from the viewpoint of significantly obtaining the intended effects of the present invention. or more, preferably 70,000 or less, more preferably 65,000 or less, particularly preferably 60,000 or less.

(d) From the viewpoint of significantly obtaining the intended effects of the present invention, the content of the thermoplastic resin is preferably 0.05% by mass or more, and more preferably The content is preferably 0.10% by mass or more, more preferably 0.15% by mass or more, preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

-(e) Curing accelerator-
In each embodiment, the resin composition may contain a curing accelerator as component (e). (e) By containing a curing accelerator, thermal curing of the resin composition can be accelerated.

(e) Examples of the curing accelerator include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, and metal-based curing accelerators. Among these, phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, and metal-based curing accelerators are preferred. (e) One type of curing accelerator may be used alone, or two or more types may be used in combination.

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

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

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

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

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

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

(e) From the viewpoint of significantly obtaining the intended effects of the present invention, the content of the curing accelerator is preferably 0.01% by mass or more, more preferably Preferably 0.03% by mass or more, more preferably 0.05% by mass or more, preferably 0.5% by mass or less, more preferably 0.3% by mass or less, even more preferably 0.2% by mass or less. be.

-(f) Other additives-
In addition to the above-mentioned components, the resin composition may further contain other additives as optional components. Examples of such additives include antioxidants, anti-discoloration agents, flame retardants; organic fillers; resin additives such as thickeners, antifoaming agents, leveling agents, and adhesion agents; etc. . These additives may be used alone or in combination of two or more.

-Method for producing resin composition-
The method for producing the resin composition according to each of the embodiments described above is not particularly limited, and examples thereof include a method in which the ingredients are mixed with a solvent, if necessary, and dispersed using a rotary mixer or the like. . The resin composition can be obtained as a resin varnish by containing a solvent, for example.

[Resin sheet]
The resin composition according to any of the embodiments described above may be used in the form of a resin sheet. The resin sheet includes a support and a resin composition layer provided on the support. The resin composition layer contains the resin composition according to any of the embodiments described above. Hereinafter, the resin composition layer and the support that the resin sheet has will be explained.

The thickness of the resin composition layer is preferably 100 μm or less, more preferably 80 μm or less, even more preferably 60 μm or less, even more preferably 40 μm or less, 30 μm or less, or 25 μm or less, from the viewpoint of making the printed wiring board thinner. . The lower limit of the thickness of the resin composition layer is not particularly limited, but can usually be 1 μm or more, 5 μm or more, 10 μm or more, etc.

(Support)
Examples of the support used for the resin sheet include a film made of a plastic material, a metal foil, and a release paper, and a film made of a plastic material and a metal foil are preferred.

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

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

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

Further, as the support, a support with a release layer having a release layer on the surface to be bonded to the resin composition layer may be used. Examples of the release agent used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. . A commercially available product may be used as the support. A commercially available product may be used as the release layer. A commercially available product may be used as the support with a release layer. These commercially available products include "Lumirror T60" manufactured by Toray Industries, "SK-1", "AL-5", "AL-7" manufactured by Lintec, "Purex" manufactured by Teijin, and "Purex" manufactured by Unitika. Examples include "Unipeel".

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

(Method for manufacturing resin sheet)
For the resin sheet, for example, a resin varnish is prepared by dissolving the resin composition described in the above [Resin sheet] in an organic solvent, and this resin varnish is applied onto a support using a coating device such as a die coater. It can be manufactured by further drying to form a resin composition layer.

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

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

In the resin sheet, a protective film similar to the support can be further laminated on the surface of the resin composition layer that is not bonded to the support (ie, the surface opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, it is possible to prevent dust and the like from adhering to the surface of the resin composition layer and from scratching it. The resin sheet can be stored by winding it up into a roll. When the resin sheet has a protective film, it can be used by peeling off the protective film.

[Manufacturing method of printed wiring board]
The method for manufacturing a printed wiring board of the present invention includes the following steps in this order.
(A) a step of preparing a laminate including an inner layer substrate and an insulating layer formed on the inner layer substrate;
(B) Process of drilling holes in the insulating layer,
(C) a step of treating the insulating layer with a swelling liquid;
(D) treating the insulating layer with an oxidizing agent solution, and
(E) Process of treating the insulating layer with a neutralizing liquid Furthermore, the method for manufacturing a printed wiring board of the present invention includes the step of (F) treating the insulating layer with an aqueous liquid having a temperature of 35° C. or higher. In the printed wiring board manufacturing method of the present invention, this step (F) is performed after the step (C) is performed and before the step (D) is performed, and/or after the step (D) is performed. and is carried out before carrying out step (E). According to the present invention, since haloing can be suppressed, the haloing region can be narrowed.

Hereinafter, each step in the method for manufacturing a printed wiring board of the present invention will be explained in the order of the steps.

<(A) Process>
In this step (A), a laminate including an inner layer substrate and an insulating layer formed on the inner layer substrate is prepared. The laminate to be prepared may be a laminate that can be manufactured using an inner substrate and a material (for example, a resin composition) that constitutes an insulating layer, or a laminate that can be manufactured using an inner substrate and a material that constitutes an insulating layer. It may be manufactured in advance using a laminate, or it may be a laminate in which a protective film or a support is bonded to the surface of an insulating layer.

(A) Steps include (A-1) forming a resin composition layer containing a resin composition on the inner layer substrate, and (A-2) thermosetting the resin composition layer on the inner layer substrate. It is preferable to include a step. By performing step (A-2), an insulating layer including a resin composition layer is formed on the inner layer substrate, and as a result, the above-mentioned laminate is prepared.

(A-1) The step includes (A-1a) preparing a resin sheet including a support and a resin composition layer containing a resin composition provided on the support; and (A-1b) ) It is preferable to include the step of laminating a resin sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate. That is, the step (A) includes (A-1a) a step of preparing a resin sheet including a support and a resin composition layer containing a resin composition provided on the support; (A-1b) It is also preferable to include a step of laminating a resin sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate, and a step of (A-2) thermosetting the resin composition layer on the inner layer substrate.

In the step (A-1a), a resin sheet including a support and a resin composition layer formed of a resin composition provided on the support is prepared. The resin sheet is as described in the above [Resin sheet].

In the step (A-1b), the resin sheet is laminated on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate. Thereby, a laminate including an inner layer substrate and a resin composition layer provided on the inner layer substrate is obtained.

The inner layer substrate is a member that becomes a substrate of a printed wiring board, and includes, for example, a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, and the like. Further, the substrate usually has a conductor layer (for example, a copper layer) on one or both sides, and this conductor layer may be patterned. An inner layer board having a conductor layer (circuit) formed on one or both sides of the board is sometimes referred to as an "inner layer printed wiring board." Further, when manufacturing a printed wiring board, an intermediate product on which an insulating layer and/or a conductive layer is further formed is also included in the "inner layer substrate" as referred to in the present invention. When the printed wiring board is a circuit board with built-in components, an inner layer board with built-in components can be used.

A resin sheet is laminated on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate to obtain a laminate. In one embodiment, the inner layer substrate and the resin sheet can be laminated, for example, by heat-pressing the resin sheet to the inner layer substrate from the support side. Examples of the member for hot-pressing the resin sheet to the inner layer substrate (hereinafter also referred to as "heat-pressing member") include a heated metal plate (SUS mirror plate, etc.), a metal roll (SUS roll), and the like. Note that, instead of pressing the thermocompression bonding member directly onto the resin sheet, it is preferable to press the resin sheet through an elastic material such as heat-resistant rubber so that the resin sheet sufficiently follows the surface irregularities of the inner layer substrate.

The inner layer substrate and the resin sheet may be laminated by a vacuum lamination method. In the vacuum lamination method, the heat-pressing temperature is preferably in the range of 60°C to 160°C, more preferably 80°C to 140°C, and the heat-pressing pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably 0. The pressure is in the range of .29 MPa to 1.47 MPa, and the heat-pressing time is preferably in the range of 15 seconds to 400 seconds, more preferably 20 seconds to 300 seconds. Lamination is preferably carried out under reduced pressure conditions of 26.7 hPa or less.

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

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

In step (A-2), the resin composition layer on the inner layer substrate is thermally cured. Thereby, an insulating layer containing a cured product of the resin composition layer is formed.

The thermosetting conditions for the resin composition layer vary depending on the type of resin composition, etc., but the curing temperature is usually 130°C or higher, preferably 150°C, and more preferably 160°C. The upper limit is, for example, 220°C or lower, preferably 210°C or lower, and more preferably 200°C or lower.

The curing time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, and preferably 120 minutes or less, more preferably 100 minutes or less, and still more preferably 90 minutes or less.

Before thermally curing the resin composition layer, the resin composition layer may be preheated at a temperature lower than the curing temperature. The preheating temperature is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, and preferably lower than 125°C, more preferably 120°C or lower, and still more preferably 110°C or lower. Further, the preheating time is preferably 5 minutes or more, more preferably 10 minutes or more, even more preferably 15 minutes or more, and preferably 150 minutes or less, more preferably 130 minutes or less, and even more preferably 120 minutes or less. be.

The maximum thickness of the insulating layer is, for example, 200 μm, and from the viewpoint of making the printed wiring board thinner, it is preferably 100 μm, more preferably 80 μm, still more preferably 60 μm, and even more preferably 50 μm or 45 μm. The lower limit of the maximum thickness of the insulating layer is not particularly limited, but is usually 0.1 μm, and may be 5 μm or 10 μm. As a result of the inventor's research, it was found that the smaller the maximum thickness of the insulating layer, the larger the haloing area tends to become. However, according to the present invention, the haloing area can be narrowed. From the viewpoint of making the printed wiring board thinner, it is possible to make the maximum thickness of the insulating layer smaller than the desired thickness, for example, 100 μm, preferably 80 μm, more preferably 60 μm, and still more preferably 50 μm or 45 μm. This is preferable because it can be done.

Here, the maximum thickness of the insulating layer is from the interface between the conductor layer (e.g. copper layer) of the inner substrate and the insulating layer to the surface of the insulating layer (or if there is another layer on the surface of the insulating layer) (to the interface with the other layer). An example of the maximum thickness of the insulating layer will be explained using FIG. 1.

FIG. 1 is a partially enlarged sectional view of an example of a laminate. The laminate 1 shown in FIG. 1 includes an inner layer substrate 10 and an insulating layer 20 formed on the inner layer substrate 10. Inner layer substrate 10 includes a conductor layer 11 and arbitrary components 12 on its outermost surface. As shown in FIG. 1, when the inner layer substrate 10 includes the component 12, the insulating layer 20 is usually formed to surround the component 12, but even in such a case, the maximum thickness of the insulating layer is , represented by t shown in FIG. That is, the maximum thickness t shown in FIG. 1 is the distance from the interface between the conductor layer 11 and the insulating layer 20 to the exposed surface of the insulating layer 20.

In one embodiment, the method for manufacturing a printed wiring board of the present invention may include the step of (a1) cooling the insulating layer to room temperature. Step (a1) is preferably carried out after step (A-2) and before step (B). Here, room temperature usually refers to 10 to 30°C, preferably 25°C.

The cooling method is not particularly limited, and the insulating layer may be allowed to cool, or the insulating layer may be forcibly cooled. When forcibly cooling the insulating layer, it may be cooled by various known methods, such as leaving the insulating layer to cool, blowing cold air on the insulating layer, or pressing the insulating layer against a cooled roll. Examples include how to apply it.

In one embodiment, the method for manufacturing a printed wiring board of the present invention includes the step of (a2) insulating layer formed after step (A-2) or after step (a1) and before step (B). The process includes a step of applying an annealing treatment to the wafer. The annealing treatment can be performed, for example, by heating the insulating layer in the atmosphere.

The temperature of the annealing treatment is 60°C or higher, preferably 65°C or higher, more preferably 70°C or higher. The upper limit is 150°C or less, preferably 140°C or less, more preferably 130°C or less, and 100°C or less.

In the annealing treatment, it is preferable to maintain a temperature of 60° C. or higher and 150° C. or lower for a predetermined period of time. The holding time is preferably 1 minute or more, more preferably 3 minutes or more, even more preferably 10 minutes or more, and preferably 90 minutes or less, more preferably 60 minutes or less, and still more preferably 40 minutes or less.

<Process (B)>
In step (B), holes are formed in the insulating layer. As a result, a via hole is usually formed in the insulating layer, and the conductor layer of the inner substrate is exposed at the bottom of the via hole.

Via holes are usually provided for electrical connection between layers, and can be formed by a known method using a drill, laser, plasma, etc., taking into consideration the characteristics of the insulating layer. For example, via holes can be formed in the insulating layer by irradiating laser light from above the support. The opening size of the via hole is selected depending on the fineness of the component to be mounted, but preferably has a top diameter in the range of 30 μm to 500 μm. The top diameter refers to the diameter of the opening of the hole (top diameter Lt, which will be described later with reference to FIG. 2).

Examples of the laser light source include a carbon dioxide laser (hereinafter also referred to as "CO ₂ laser"), a YAG laser, an excimer laser, and the like. Among these, carbon dioxide laser is preferred from the viewpoint of processing speed and cost.

When a carbon dioxide laser device is used as a laser light source, a laser beam with a wavelength of 9.3 μm to 10.6 μm is generally used. Further, the number of shots varies depending on the depth and diameter of the via hole to be formed, but is usually selected in the range of 1 to 10 shots. From the viewpoint of increasing the processing speed and improving the productivity of printed wiring boards, the number of shots is preferably small, preferably in the range of 1 to 5 shots, and more preferably in the range of 1 to 3 shots. Note that when the number of shots is two or more, the laser light may be irradiated in either burst mode or cycle mode.

When using a carbon dioxide laser device as a laser light source, the energy of the laser light is preferably 0.25 mJ or more, more preferably 0.5 mJ or more, although it depends on the number of shots, the depth of the via hole, and the thickness of the support. , more preferably set to 1 mJ or more. The upper limit of the energy of the laser beam is preferably 20 mJ or less, more preferably 15 mJ or less, even more preferably 10 mJ or less.

The drilling process can be performed using a commercially available laser device. Commercially available carbon dioxide laser devices include, for example, LC-2E21B/1C manufactured by Hitachi Via Mechanics, “LC-K212” manufactured by HITACHI, ML605GTWII manufactured by Mitsubishi Electric, and substrate drilling laser manufactured by Matsushita Welding Systems. Examples include processing machines.

In one embodiment, the method for manufacturing a printed wiring board of the present invention includes the step of (b1) performing an annealing treatment on the insulating layer after performing the step (B) and before implementing the step (C). The conditions for the annealing treatment in step (b1) are the same as those for the annealing treatment in (a2). When step (a2) is performed, step (b1) may be omitted.

<Desmear processing>
After carrying out step (B) or after carrying out step (b1), the laminate is subjected to a desmear process (desmear process). The desmear process includes (C) a process of treating the insulating layer with a swelling liquid (swelling process), (D) a process of treating the insulating layer with an oxidizing agent solution (oxidation process), and (E) a process of treating the insulating layer with a neutralizing liquid. A processing step (neutralization step) is included in this order. In addition, the method for manufacturing a printed wiring board of the present invention includes (F) a step of treating the insulating layer with an aqueous liquid at a temperature of 35° C. or higher (described later (Fc1 ) step and (Fd1) step or both). Furthermore, the desmear process may include a swelling process, an oxidation process, a neutralization process, and processes other than the (F) process.

<(C) Process: Swelling process>
In step (C), the insulating layer is treated with a swelling liquid. Usually, step (C) includes a step of bringing the insulating layer into contact with a swelling liquid. The swelling liquid comes into contact with the insulating layer on the wall surface of the via hole, and usually also comes into contact with the conductor layer of the inner layer substrate exposed at the bottom of the via hole. Although the type and conditions of the treatment are not particularly limited as long as the wall surface of the via hole formed in the insulating layer comes into contact with the swelling liquid, for example, step (C) includes a step of immersing the laminate in the swelling liquid. The temperature of the swelling liquid is preferably 30 to 90°C, and more preferably 40 to 80°C from the viewpoint of suppressing the swelling of the resin constituting the insulating layer to an appropriate level. The immersion time in the swelling liquid is preferably 1 minute to 20 minutes, and more preferably 5 minutes to 15 minutes from the viewpoint of suppressing the swelling of the resin constituting the insulating layer to an appropriate level. Moreover, it is preferable to vibrate the swelling liquid while the laminate is immersed in the swelling liquid.

Examples of the swelling liquid include alkaline solutions and surfactant solutions. Among these, as the swelling liquid, an alkaline solution is preferable, and as the alkaline solution, an aqueous solution of an alkali metal hydroxide (for example, potassium hydroxide, sodium hydroxide) is more preferable.
Commercially available swelling liquids include, for example, "Swelling Dip Securiganth P" and "Swelling Dip Securiganth SBU" manufactured by Atotech Japan. can be mentioned.

<(Fc1) Process: Treatment with aqueous liquid>
The method for manufacturing a printed wiring board of the present invention includes a step (Fc1) of treating the insulating layer with an aqueous liquid at a temperature of 35° C. or higher after the step (C) and before the step (D). F) May be included as a step.

In the (Fc1) step, the insulating layer is treated with an aqueous liquid at a temperature of 35° C. or higher. Usually, the step (Fc1) includes a step of bringing the insulating layer into contact with an aqueous liquid at a temperature of 35° C. or higher. The aqueous liquid contacts the insulating layer on the wall surface of the via hole, and usually also contacts the conductive layer of the inner layer substrate exposed at the bottom of the via hole. Although the type and conditions of this treatment are not particularly limited, for example, the step (Fc1) includes a step of immersing the laminate in an aqueous liquid. The step (Fc1) may be performed multiple times after the step (C) is performed and before the step (D) is performed. By performing the step (Fc1), the haloing region can be narrowed. Further, as a result of performing the step (Fc1), it is acceptable that the swelling liquid that had adhered to the laminate before the step is removed. The aqueous liquid may contain any solute as long as the effects of the present invention are exhibited, but water is preferable. Various types of water can be used depending on the purpose. As water, for example, tap water or industrial water may be used, and pure water such as RO water, deionized water, distilled water (electrical resistivity: 0.1 MΩ·cm or more and less than 1.5 MΩ·cm) or super Pure water (electrical resistivity: 1.5 MΩ·cm or more) may be used.

From the viewpoint of narrowing the haloing region, the temperature of the aqueous liquid is preferably within a range of 35°C or higher and below the boiling point, more preferably within a range of 40°C or higher and 100°C or lower, and 50°C or higher. It is even more preferable that there be. The temperature of the aqueous liquid may be, for example, 60°C or higher, 70°C or higher, or 90°C or lower. The immersion time in the aqueous liquid may be short as long as the desired effect of the present invention is achieved, for example, it may be 30 seconds or more or 45 seconds or more; From this point of view, the time is preferably 1 minute or more, more preferably 3 minutes or more, and still more preferably 5 minutes or more. The upper limit of the immersion time is not limited as long as it is allowable in terms of the manufacturing process, but may be, for example, 90 minutes or less, 60 minutes or less, or 30 minutes or less. Further, while the laminate is immersed in the aqueous liquid, it is preferable to perform at least one of circulating the aqueous liquid in the bath and vibrating the aqueous liquid, and circulating the aqueous liquid in the bath. It is more preferable.

<(Gc2) process: cleaning process>
The method for manufacturing a printed wiring board of the present invention includes a step (Gc2) of washing the surface of the insulating layer with water at a temperature of less than 35° C. after the step (C) and before the step (D). ) may be included as a step. The (Gc2) step may include a step of immersing the laminate in water at a temperature below 35°C, a step of spraying water at a temperature below 35°C toward the insulating layer, or both. It may include the steps of If step (Fc1) is not performed, step (Gc2) is performed after step (C) is performed; if step (Fc1) is performed, step (Gc2) is performed before step (Fc1). Alternatively, it may be carried out after the (Fc1) step is carried out. The step (Gc2) may be performed multiple times after the step (C) is performed and before the step (D) is performed.

By performing the step (Gc2) after the step (Fc1) described above, the laminate is washed and the swelling liquid that may be contained in the aqueous liquid used in the step (Fc1) is removed, albeit at an extremely low concentration. be able to. By performing the (Gc2) step before the above-mentioned (Fc1) step, the laminate from which the swelling liquid has been removed can be subjected to the (Fc1) step, and if the (Fc1) step is not performed, , the same laminate can be subjected to step (D).

When carrying out the step (Fc1), the subsequent step (D) may be carried out without carrying out the step (Gc1). Alternatively, the (Gc1) step may be performed without performing the (Fc1) step, and the subsequent (D) step may be performed. In this case, the laminate from which the swelling liquid has been removed is used in the (D) step. After that, the step (Fd1) described later is performed.

<(D) Step: Oxidation step>
In step (D), the insulating layer is treated with an oxidant solution. As a result, the resin on the surface of the insulating layer is oxidized and can be removed as a smear. Usually, step (D) includes a step of bringing the insulating layer into contact with an oxidizing agent solution. The oxidizing agent solution contacts the insulating layer on the wall surface of the via hole, and usually also contacts the conductive layer of the inner layer substrate exposed at the bottom of the via hole. The type and conditions of the treatment are not particularly limited as long as the wall surface of the via hole formed in the insulating layer comes into contact with the oxidizing agent solution, but for example, a known type commonly used as an oxidation process when forming an insulating layer of a printed wiring board. and conditions may be adopted. For example, step (D) includes a step of immersing the laminate in an oxidizing agent solution.

As the oxidizing agent solution, an oxidizing agent solution used in normal desmear processing can be used. Examples of such an oxidizing agent solution include an alkaline permanganate solution in which potassium permanganate or sodium permanganate is dissolved in an aqueous solution of sodium hydroxide. The oxidizing agent concentration of the oxidizing agent solution is preferably 3% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and preferably 20% by mass or less, more preferably 15% by mass. The content is preferably 10% by mass or less.

A commercially available product may be used as the oxidizing agent solution. Examples of commercially available oxidizing agent solutions include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigance P" manufactured by Atotech Japan.

From the viewpoint of efficiently desmearing, the oxidizing agent solution is preferably heated or heated and kept at a constant temperature. The temperature of the oxidizing agent solution is preferably 60°C or higher, more preferably 65°C or higher, even more preferably 70°C or higher, and preferably 95°C or lower, more preferably 90°C or lower, and even more preferably 90°C or lower. be.

Further, the immersion time in the oxidizing agent solution is preferably 5 minutes, more preferably 10 minutes, even more preferably 15 minutes, preferably 40 minutes, more preferably 35 minutes, and still more preferably 30 minutes. Further, it is preferable to vibrate the oxidizing agent solution while the laminate is immersed in the oxidizing agent solution.

<(Fd1) Process: Treatment with aqueous liquid>
The method for manufacturing a printed wiring board of the present invention includes a step (Fd1) of treating an insulating layer with an aqueous liquid at a temperature of 35° C. or higher after step (D) and before step (E). F) May be included as a step.

In the step (Fd1), the insulating layer is treated with an aqueous liquid at a temperature of 35° C. or higher. Usually, the step (Fd1) includes a step of bringing the insulating layer into contact with an aqueous liquid at a temperature of 35° C. or higher. The aqueous liquid contacts the insulating layer on the wall surface of the via hole, and usually also contacts the conductive layer of the inner layer substrate exposed at the bottom of the via hole. Although the type and conditions of this treatment are not particularly limited, for example, the step (Fd1) includes a step of immersing the laminate in an aqueous liquid. The step (Fd1) may be performed multiple times after the step (E) is performed and before the step (E) is performed. By performing the step (Fd1), the haloing region can be narrowed. Further, as a result of performing the step (Fd1), it is acceptable that the swelling liquid that had adhered to the laminate before the step is removed. The aqueous liquid may contain any solute as long as the effects of the present invention are exhibited, but water is preferable. Various types of water can be used depending on the purpose. As water, for example, tap water or industrial water may be used, and pure water such as RO water, deionized water, distilled water (electrical resistivity: 0.1 MΩ·cm or more and less than 1.5 MΩ·cm) or super Pure water (electrical resistivity: 1.5 MΩ·cm or more) may be used.

From the viewpoint of narrowing the haloing region, the temperature of the aqueous liquid is preferably within a range of 35°C or higher and below the boiling point, more preferably within a range of 40°C or higher and 100°C or lower, and 50°C or higher. It is even more preferable that there be. The temperature of the aqueous liquid may be, for example, 60°C or higher, 70°C or higher, or 90°C or lower. The immersion time in the aqueous liquid may be short as long as the desired effect of the present invention is achieved, for example, it may be 30 seconds or more or 45 seconds or more, but from the viewpoint of ensuring that the desired effect of the present invention is achieved. The time is preferably 1 minute or more, more preferably 3 minutes or more, and even more preferably 5 minutes or more. The upper limit of the immersion time is not limited as long as it is an allowable time for the process, but may be, for example, 90 minutes or less, 60 minutes or less, or 30 minutes or less. Further, while the laminate is immersed in the aqueous liquid, it is preferable to perform at least one of circulating the aqueous liquid in the bath and vibrating the aqueous liquid, and circulating the aqueous liquid in the bath. It is more preferable.

<(Gd2) process: cleaning process>
The method for manufacturing a printed wiring board of the present invention includes a step (Gd2) of washing the surface of the insulating layer with water at a temperature below 35° C. after the step (D) and before the step (E). ) may be included as a step. The (Gd2) step may include a step of immersing the laminate in water at a temperature below 35°C, a step of spraying water at a temperature below 35°C toward the insulating layer, or both. It may include the steps of If step (Fd1) is not carried out, step (Gd2) is carried out after step (D) is carried out, and if step (Fd1) is carried out, it is carried out before step (Fd1) is carried out. Alternatively, it may be carried out after the step (Fd1) is carried out. The step (Gd2) may be performed multiple times after the step (D) is performed and before the step (E) is performed.

By performing the (Gd2) step after the above-mentioned (Fd1) step, the laminate is washed and the swelling liquid that may be contained in the aqueous liquid used in the (Fd1) step is removed, albeit at an extremely low concentration. be able to. By performing the (Gd2) step before the above-mentioned (Fd1) step, the laminate from which the oxidizer solution has been removed can be subjected to the (Fd1) step, and when the (Fd1) step is not performed, The same laminate can be subjected to the (Fd1) process.

When carrying out the step (Fd1), the subsequent step (E) may be carried out without carrying out the step (Gd1). Further, when the above-mentioned step (Fc1) is performed, the step (Fd1) may also be performed. That is, step (F) is performed after performing step (C) and before performing step (D), and after performing step (D) and before performing step (E). Ru.

<(E) Process: Neutralization process>
In step (E), the insulating layer is treated with a neutralizing liquid. Usually, the step (E) includes a step of bringing the insulating layer into contact with a neutralizing liquid. The neutralizing liquid comes into contact with the insulating layer on the wall surface of the via hole, and usually also comes into contact with the conductive layer of the inner layer substrate exposed at the bottom of the via hole. By carrying out step (E), residues such as oxidizing agent salts contained in the oxidizing agent solution used in step (D) can be removed. The type and conditions of the treatment are not particularly limited as long as the wall surface of the via hole formed in the insulating layer comes into contact with the neutralizing liquid, but for example, step (E) includes a step of immersing the laminate in the neutralizing liquid.

As the neutralizing liquid, it is preferable to use an acidic aqueous solution. A commercially available neutralizing liquid may be used, and examples of commercially available neutralizing liquids include "Reduction Solution Securigance P" manufactured by Atotech Japan.

The temperature of the neutralizing solution is preferably 20°C or higher, more preferably 25°C or higher, even more preferably 30°C or higher, and preferably 80°C or lower, from the viewpoint of removing oxidizing agent salt residues. , more preferably 75°C or lower, still more preferably 70°C or lower.

The immersion time in the neutralizing solution is preferably 1 minute or more, more preferably 2 minutes or more, still more preferably 3 minutes or more, and preferably 30 minutes, from the viewpoint of removing oxidizing agent salt residues, etc. The time is preferably 25 minutes or less, and even more preferably 20 minutes or less. Further, it is preferable to vibrate the neutralizing liquid while the laminate is immersed in the neutralizing liquid.

<(Ge1) process: cleaning process>
The method for manufacturing a printed wiring board of the present invention may further include a step of washing the surface of the insulating layer (Ge1) with water at a temperature of less than 35° C. after the step (E). The treatment in the (Ge1) step is similar to the treatment in the (Gc2) step or (Gd2) step described above. By performing the step (Ge1) after the step (E), the laminate can be washed and the oxidizing agent solution that may be contained in the neutralizing solution used can be removed, albeit at an extremely low concentration. (Ge1) step may be performed multiple times.

<Other processes>
The method for manufacturing a printed wiring board of the present invention may further include the step (H) of forming a conductor layer on the surface of the insulating layer, and this step (H) is carried out after the step (E).

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

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

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

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

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

The support can be placed between steps (A-1b) and (A-2), between steps (A-2) and (B), between steps (B) and (C), or It may be removed after the step (C). Further, after each step is completed, washing treatment may be performed with water as necessary.

[Printed wiring board]
The printed wiring board obtained by the manufacturing method of the present invention has a narrowed haloing area. Therefore, it is possible to narrow the pitch of the via holes, thereby realizing finer circuit wiring and higher density.

Hereinafter, the haloing area will be explained using FIG. 2.

FIG. 2 is a partially enlarged top view of the laminate in which the insulating layer of the laminate has been drilled, when viewed from the insulating layer side.

The laminate 100 shown in FIG. 2 includes an inner substrate (not shown) having a conductor layer 111 on its surface, and an insulating layer 120 formed on the surface of the conductor layer 111 of the inner substrate. As a result of drilling the insulating layer 120 from the insulating layer surface 120U side, a via hole 130 is formed in the insulating layer 120, the outer shape being circular in top view and rectangular in cross section. At the bottom surface 130B of the via hole 130, the surface 111U of the conductor layer 111 is exposed. Generally, the rectangular cross-sectional shape of the via hole 130 often has a forward taper shape in which the diameter decreases from the insulating layer surface 120U toward the conductor layer surface 111U, and FIG. An example is shown in which the top outline 120T of the insulating layer 120 and the bottom outline 120B of the insulating layer along the bottom outline of the forward tapered shape are visible.

Although not all the causes of haloing have been clarified, it is known that it tends to be observed after the drilling process and the desmear process. In FIG. 2, the haloing region is generally observed as a hollow disc-shaped region indicated at 140. The haloing region 140 can be observed by irradiating the laminate 100 with light from the insulating layer surface 120U side. The reflected light from the conductor layer 111 in the haloing region is the reflected light from the surrounding conductor layer 111 (this reflected light is often visually recognized as brown color due to copper when the conductor layer 111 is a copper layer). ), the haloing area is visually recognized as a part with a different color.

The width of the harrowing can be evaluated by the diameter Rh of the harrowing region 140 or by the relative length of the via hole 130 with respect to the top diameter Lt. FIG. 2 shows the diameter Rh of the harrowing region 140 and the top diameter Lt of the via hole 130. The diameter Rh of the harrowing region 140 is the diameter when the outline 190 of the harrowing region 140 is regarded as a circle, and can be measured as the diameter passing through the center point 130C of the via hole 130. The top diameter Lt of the via hole 130 is the diameter when the upper outline 120T of the insulating layer 120 is regarded as a circle, and can be measured as the diameter passing through the center point 130C of the via hole 130.

The laminate included in the printed wiring board manufactured by the manufacturing method of the present invention usually has a characteristic that the diameter Rh (μm) of the harrowing region shown in FIG. 2 is small. For example, when the maximum thickness t of the insulating layer 120 is 40 μm and the top diameter Lt of the via hole 130 or the target diameter during drilling is 50 μm, the diameter Rh (μm) of the harrowing region is, for example, 102 μm or less. , preferably 101 μm or less, more preferably 100 μm or less. A printed wiring board including a laminate having such a small diameter Rh (μm) of the harrowing region is evaluated as having a narrowed harrowing region, as illustrated in the Examples section.

[Semiconductor device]
Using the printed wiring board obtained by the manufacturing method of the present invention, a semiconductor device including such a printed wiring board can be manufactured. The printed wiring board obtained by the manufacturing method of the present invention can realize finer circuit wiring and higher density, so it can realize smaller size and higher functionality of electronic equipment equipped with semiconductor devices. can.

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

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

The mounting method of the semiconductor chip when manufacturing the semiconductor device of the present invention is not particularly limited as long as the semiconductor chip functions effectively, but specifically, wire bonding mounting method, flip chip mounting method, non-bump mounting method, etc. Examples 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, "a mounting method using a bumpless buildup layer (BBUL)" refers to a "mounting method in which a semiconductor chip is directly embedded in a recess of a printed wiring board and the semiconductor chip and wiring on the printed wiring board are connected." It is.

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

[Example 1]
By carrying out the following steps (1) to (12), an evaluation board after desmear treatment was obtained. Using the obtained desmear-treated evaluation board, the width of the desmear area was evaluated as described below.

Step (1): Preparation of resin varnish 30 parts of biphenyl-type epoxy resin (“NC3000H” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: approximately 290), naphthalene-type tetrafunctional epoxy resin (“HP-4700” manufactured by DIC Corporation, epoxy equivalent) : 162) 5 parts, liquid bisphenol A type epoxy resin (Mitsubishi Chemical Corporation "jER828EL", epoxy equivalent: 180) 15 parts, and phenoxy resin (Mitsubishi Chemical Corporation "YX7553BH30", weight average molecular weight: 35000, non-volatile component 30 2 parts of methyl ethyl ketone (MEK) solution was heated and dissolved in a mixed solvent of 8 parts of MEK and 8 parts of cyclohexanone while stirring. There, 32 parts of a triazine skeleton-containing phenol novolac curing agent ("LA-7054" manufactured by DIC, phenolic hydroxyl equivalent: about 124, MEK solution with non-volatile components of 60% by mass), and tetrabutyl as a phosphorus curing accelerator. Spherical silica surface-treated with 0.2 parts of phosphonium decanoate ("TBP-DA" manufactured by Hokko Chemical Co., Ltd.) and an aminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) ("SO-C2" manufactured by Admatex Co., Ltd.) ”, average particle size: 0.5 μm, specific surface area: 5.8 m ² /g) 160 parts, polyvinyl butyral resin solution (Sekisui Chemical Co., Ltd. “KS-1”, weight average molecular weight: 27000, glass transition temperature: 105 ℃, 2 parts of a mixed solution of 15% by mass of non-volatile components of ethanol and toluene in a mass ratio of 1:1) were mixed and uniformly dispersed with a high-speed rotating mixer to prepare a resin varnish. Hereinafter, the resin varnish prepared in this way will also be referred to as "resin varnish A." When the mass of non-volatile components in resin varnish A was taken as 100% by mass, the content of spherical silica as an inorganic filler was 69.5% by mass.

Step (2): Preparation of resin sheet A long PET film with an alkyd resin release layer (“AL-5” manufactured by Lintec Corporation, width 672 mm, thickness 38 μm, hereinafter referred to as “release PET film”). ) was prepared as a support. The resin varnish A prepared in step (1) above was applied onto the release layer of this support using a die coater, so that two coated parts (resin composition layers) with a coating length of 506 mm were separated from each other. It was applied intermittently to a uniform thickness so that it was formed. However, in the width direction perpendicular to the coating direction, an uncoated part (hereinafter also referred to as "width direction uncoated part") with a width of 0.5 mm from the end is provided at both ends of the support, and Regarding the coating direction, an uncoated part (hereinafter also referred to as "uncoated part in the coating direction") having a length in the coating direction of 1 mm was provided between two coated parts.
Thereby, a resin sheet containing a support and two resin composition layers provided on the release layer of the support was obtained. In this resin sheet, from one end in the width direction to the other end, there is a first uncoated part in the width direction with a width of 0.5 mm, a resin composition layer with a width of 506 mm, and a second uncoated part in the width direction with a width of 0.5 mm. The coated areas were lined up in this order, and two resin composition layers were lined up in the coating direction separated from each other with an uncoated area in the coating direction having a length of 1 mm in the coating direction.
Thereafter, the resin composition layer of the resin sheet was dried at 80°C to 120°C (average 100°C) for 6 minutes. The thickness of each resin composition layer after drying contained in the resin sheet was 40 μm, and the amount of residual solvent was about 2% by mass.
Next, a polypropylene film (thickness: 15 μm) was bonded to the resin composition layer as a protective film and wound up into a roll.
The obtained rolled resin sheet was slit at a position 336 mm from one end in the width direction (ie, at the center position in the width direction). Furthermore, the rolled resin sheet was spread out and slit at the center of the uncoated area in the coating direction (that is, at the uncoated area between the two resin composition layers). Furthermore, it was cut so that the length of the uncoated parts at both ends in the coating direction was 0.5 mm. As a result, a single wafer type resin sheet (external dimensions: 507 mm x 336 mm) was obtained with coated area dimensions of 506 mm x 335.5 mm and an uncoated area of 0.5 mm on three sides of the coated area. . Hereinafter, the single-wafer type resin sheet produced in this way will also be referred to as "resin sheet B."

Step (3): Preparation of inner layer substrate Glass cloth base epoxy resin double-sided copper-clad laminate with copper layers on both surfaces (copper layer thickness 18 μm, substrate thickness 0.8 mm, manufactured by Panasonic Electric Works Co., Ltd. "R1515A" ) was prepared as an inner layer substrate. Both surfaces of the inner layer substrate were immersed in "CZ8100" manufactured by MEC Corporation to roughen the surface of the copper layer.

Step (4): Lamination of resin sheet B The resin sheet B produced in step (2) above is laminated with a resin composition layer using a batch vacuum pressure laminator (“MVLP-500” manufactured by Meiki Manufacturing Co., Ltd.). Both sides of the inner layer substrate were laminated so as to be bonded to the inner layer substrate. The lamination process was performed by reducing the pressure for 30 seconds to bring the atmospheric pressure to 13 hPa or less, and then press-bonding at 100° C. and a pressure of 0.74 MPa for 30 seconds. Note that the resin sheet B was used after the protective film was peeled off before lamination treatment. Thereby, a laminate including an inner layer substrate, and a resin composition layer and a support layer laminated on both surfaces of the inner layer substrate was obtained. Hereinafter, the laminate obtained in this way will also be referred to as "laminate C".

Step (5): Heat curing of resin composition layer The laminate C, with the support attached, was heated at 100°C (temperature T1) for 30 minutes, and then heated at 180°C (temperature T2) for 30 minutes. , the resin composition layer included in the laminate C was thermally cured. This formed an insulating layer. The maximum thickness of the obtained insulating layer was 40 μm. Here, the maximum thickness of the insulating layer means the distance from the interface between the copper layer and the insulating layer of the inner layer substrate to the interface between the insulating layer and the support. In this way, a laminate including an inner layer substrate and an insulating layer formed on the inner layer substrate was prepared. Hereinafter, the laminate obtained in this way will also be referred to as "laminate D".

Step (6): Drilling with CO ₂ laser A CO ₂ laser processing machine (“LC-K212” manufactured by HITACHI) was applied to the insulating layer on one main surface side of the laminate D with the support attached. Holes were drilled at three or more locations using a power: 1.35 W, number of shots: 2, and target top diameter: 50 μm. As a result, a plurality of via holes having a generally circular top view and a rectangular cross-sectional outline were formed, opening onto the circuit conductor of the inner substrate, and the conductor layer of the inner substrate was exposed at the bottom of each via hole. Hereinafter, the laminate in which the insulating layer is drilled in this manner will also be referred to as "laminate E".

Step (7): Swelling step Two supports were peeled off from the laminate E obtained in step (6) above to expose insulating layers on both sides. As a result, a laminate in which the insulating layer was exposed was obtained. Hereinafter, the laminate in which the insulating layer is exposed in this way will also be referred to as "laminate F." Subsequently, the laminate F was immersed for 10 minutes in a 60° C. swelling liquid (“Swelling Dip Securigance P” manufactured by Atotech Japan, an aqueous sodium hydroxide solution containing diethylene glycol monobutyl ether) while being vibrated.

Step (8): Treatment using aqueous liquid Laminated body F was taken out from the swelling liquid, and then immersed for 10 minutes in a bath in which 40° C. water (deionized water) was circulated as an aqueous liquid. Table 1 shows the temperature of the treatment liquid used in step (8) and the immersion time in the treatment liquid.

Step (9): Oxidation step The laminate F was removed from the treatment solution used in step (8), and then an oxidizing agent solution (“Concentrate Compact CP” manufactured by Atotech Japan Co., Ltd., potassium permanganate concentration) was added at 80°C. The sample was immersed for 20 minutes while being vibrated in an aqueous solution with a sodium hydroxide concentration of about 6% by mass and about 4% by mass.

Step (10): Treatment using washing water below 35°C The laminate F was taken out of the oxidizing agent solution and then placed in a bath in which water (deionized water) at 15°C was circulated as washing water for 10 minutes. Soaked. Table 1 shows the temperature and immersion time of the treatment liquid used in step (10).

Step (11): Neutralization step The laminate F is removed from the treatment solution used in step (10), and then a neutralization solution (“Reduction Solution Securigance P” manufactured by Atotech Japan Co., Ltd., manufactured by Atotech Japan Co., Ltd., hydroxylamine sulfate) is added at 40°C. (aqueous solution) for 5 minutes.

Step (12): Water washing and drying Laminated body F was taken out from the neutralizing solution, and then immersed for 10 minutes in a bath in which 15° C. water (deionized water) was circulated as washing water. As a result, the neutralizing liquid was removed and the laminate F was cleaned. Thereafter, the laminate F was taken out of the bath and dried at 80° C. for 30 minutes. The laminate F subjected to the desmear treatment including at least steps (7), (9), and (11) as described above is hereinafter also referred to as "evaluation board G."

Step (13): Evaluation step Regarding the evaluation board G, the haloing region was evaluated. Generally speaking, the haloing area was observed according to <Evaluation of the haloing area> described later, and the width of the haloing area was evaluated based on the observation results.

[Examples 2 to 6]
In Examples 2 to 6, in Example 1, the temperature of the aqueous liquid as the treatment liquid used in step (8) was changed from 40°C to 50°C, 60°C, 70°C, 80°C, and 90°C, respectively. did. Except for the above matters, an evaluation board G was obtained through the same steps as in Example 1, and was subjected to evaluation in step (13).

[Example 7]
In Example 7, instead of Step (8) and Step (10) carried out in Example 1, the following Step (8') and Step (10') were carried out, respectively.

Step (8'): Treatment using washing water below 35°C The laminate F was taken out of the swelling solution and then placed in a bath in which water (deionized water) at 15°C was circulated as washing water for 10 minutes. Soaked. Table 1 shows the temperature of the treatment liquid used in step (8') and the immersion time in the treatment liquid.

Step (10'): Treatment using aqueous liquid Laminated body F was taken out from the oxidizing agent solution, and then immersed for 10 minutes in a bath in which 70° C. water (deionized water) was circulated as the aqueous liquid. Table 1 shows the temperature of the treatment liquid used in step (10') and the immersion time in the treatment liquid.

Except for the above matters, an evaluation board G was obtained through the same steps as in Example 1, and was subjected to evaluation in step (13).

[Example 8 and 9]
In Examples 8 and 9, the temperature of the aqueous liquid as the treatment liquid used in step (10') in Example 7 was changed from 70°C to 80°C and 90°C, respectively. Except for the above matters, an evaluation board G was obtained through the same steps as in Example 7, and was subjected to evaluation in step (13).

[Example 10]
In Example 10, the immersion time in the aqueous liquid as the treatment liquid used in step (8) in Example 5 was changed from 10 minutes to 30 minutes. Except for the above matters, an evaluation board G was obtained through the same steps as in Example 5, and was subjected to evaluation in step (13).

[Example 11]
In Example 11, the following step (10'') was carried out in place of step (10) carried out in Example 5.
Step (10"): Treatment with aqueous liquid The laminate F was removed from the oxidizing agent solution and then immersed for 10 minutes in a bath in which water at 80° C. was circulated as the aqueous liquid. Step (10") Table 2 shows the temperature of the treatment liquid used and the immersion time in the treatment liquid.
Except for the above matters, an evaluation board G was obtained through the same steps as in Example 5, and was subjected to evaluation in step (13).

[Comparative example 1]
In Comparative Example 1, the following step (8') was carried out in place of step (8) carried out in Example 1.
Step (8'): Treatment using washing water below 35°C The laminate F was taken out of the swelling solution and then placed in a bath in which water (deionized water) at 15°C was circulated as washing water for 10 minutes. Soaked. Table 2 shows the temperature of the treatment liquid used in step (8') and the immersion time in the treatment liquid.
That is, in Comparative Example 1, the temperature was 35°C or higher after the implementation of step (7) and before the implementation of step (9), and after the implementation of step (9) and before the implementation of step (11). No step was carried out to treat the insulation layer with an aqueous liquid at a temperature of . Except for the above matters, an evaluation board G was obtained through the same steps as in Example 1, and was subjected to evaluation in step (13).

[Comparative Examples 2 and 3]
In Comparative Examples 2 and 3, the temperature of the aqueous liquid as the treatment liquid used in step (8') in Comparative Example 1 was changed from 15°C to 20°C and 30°C, respectively. Except for the above matters, an evaluation board G was obtained through the same steps as in Comparative Example 1, and was subjected to evaluation in step (13).

[Comparative example 4]
In Comparative Example 4, the following step (8') was carried out in place of step (8) carried out in Example 1. Further, the temperature of the cleaning water used as the treatment liquid used in step (10) in Example 1 was changed from 15°C to 30°C.

Step (8'): Treatment using washing water below 35°C The laminate F was taken out of the swelling solution and then placed in a bath in which water (deionized water) at 15°C was circulated as washing water for 10 minutes. Soaked. Table 2 shows the temperature of the treatment liquid used in step (8') and the immersion time in the treatment liquid.

That is, in Comparative Example 4, the temperature was 35°C or higher after the implementation of step (7) and before the implementation of step (9), and after the implementation of step (9) and before the implementation of step (11). No step was carried out to treat the insulation layer with an aqueous liquid at a temperature of . Except for the above matters, an evaluation board G was obtained through the same steps as in Example 1, and was subjected to evaluation in step (13).

<Evaluation of haloing area>
Each evaluation board G obtained in Examples 1 to 11 and Comparative Examples 1 to 4 was observed using a CMOS image sensor (“Digital Microscope VHX-7000” manufactured by Keyence Corporation) while irradiating light from above the insulating layer. By doing so, we identified the haloing region near the via hole. Here, even if the insulating layer contains a high amount of inorganic filler, the thickness of the haloing region is as small as 40 μm. The reflected light transmits through the insulating layer in an area different from the haloing area and is different from the light reflected by the underlying copper layer, so it can be visually recognized as a different color, and as a result, the haloing area can be clearly identified. was completed.

Subsequently, the diameter (μm) of the outer periphery of three of the identified haloing regions was measured, and the average value thereof was calculated (n=3).
Then, the diameter of the obtained haloing region was evaluated according to the following criteria. Measured values and evaluation results are shown in Tables 1 and 2. Since Comparative Example 1 was used as the standard, the width of the haloing region was not evaluated for Comparative Example 1.
"○": The measured value (average value) of the diameter of the harrowing region is such that the absolute value of the difference (diameter difference) from the diameter of 102 μm of the harrowing region of Comparative Example 1 is 10 μm or more, and the diameter of the harrowing region is sufficient. Narrowing is observed "×": The measured value (average value) of the diameter of the haloing region is less than 10 μm in absolute value (diameter difference) from the diameter of 102 μm of the harrowing region in Comparative Example 1, and the halo No narrowing of the ing area was observed.

Further, in Example 1, it was confirmed by cross-sectional observation that the haloing region corresponded to the peeling region that occurred at the interface between the insulating layer and the copper layer. Here, the cross-sectional observation was performed by cutting out a cross section of the evaluation substrate G including the diameter of the via hole using an FIB (focused ion beam), and observing the cut out cross section with an electron microscope.

FIG. 3 is a partially enlarged sectional view schematically showing a cross section of the laminate along line III-III (a line passing through the center point 130C of the via hole) in FIG. The symbols shown in FIG. 3 are the same as those shown in FIG. The reference numeral 110 shown in FIG. 3 is an inner layer substrate including a copper layer as the conductor layer 111, and the reference numeral 150 indicates a peeled region generated at the interface. An end 150E of the peeled region 150 is an end opposite the bottom outline 120B of the insulating layer 120. The diameter Rp shown in FIG. 3 corresponds to the distance from one end 150E of the peeled region 150 to the other end 150E passing through the center point 130C of the via hole 130. As a result of the above cross-sectional observation, the average value of the diameter Rp shown in FIG. 3 was 91 μm for the three via holes 130 whose diameters of the haloing regions were measured in Example 1. It was confirmed that the average diameter Rh of the ing region 140 coincided with the average value of 91 μm with high accuracy.

<Consideration>
As can be seen from Tables 1 and 2, from the comparison between Examples and Comparative Examples, it is possible to provide a printed wiring board manufacturing method that can narrow the haloing area by implementing the following specific steps. Do you get it.
・After the swelling step (step (7)) and before the oxidation step (step (9)), a process is performed using water at a temperature of 35°C or higher as an aqueous liquid.・Oxidation step After performing (step (9)) and before implementing the neutralization step (step (11)), performing a treatment using water at a temperature of 35 ° C. or higher as an aqueous liquid, or
- After the swelling step (step (7)) and before the oxidation step (step (9)), a treatment using water at a temperature of 35°C or higher as an aqueous liquid is carried out, and the oxidation step ( After performing step (9)) and before implementing the neutralization step (step (11)), performing a treatment using water at a temperature of 35 ° C. or higher as an aqueous liquid.

1 Laminated body 10 Inner layer substrate 11 Conductive layer 12 Component 100 Laminated body 110 Inner layer substrate 111 Conductor layer 120 Insulating layer 130 Via hole 140 Haloing region 150 Peeling region

Claims (8)

(A) preparing a laminate including an inner layer substrate and an insulating layer formed on the inner layer substrate;
(B) Process of drilling holes in the insulating layer,
(C) a step of treating the insulating layer with a swelling liquid;
(D) treating the insulating layer with an oxidizing agent solution, and
(E) A method for manufacturing a printed wiring board, comprising the steps of treating an insulating layer with a neutralizing liquid in this order,
moreover,
(F) a step of immersing the laminate in a bath in which an aqueous liquid having a temperature of 35° C. or higher is circulated ;
(F) performing the step after performing the (C) step and before performing the (D) step; and/or after performing the (D) step and before performing the (E) step. ,
A method for producing a printed wiring board , in which the insulating layer is treated at a temperature of the aqueous liquid at 60° C. or higher and 70° C. or lower, if performed after the step (C) and before the step (D) . (A) The process is
forming a resin composition layer containing a resin composition on the inner layer substrate, and
The method for manufacturing a printed wiring board according to claim 1 , comprising the step of thermosetting the resin composition layer on the inner layer substrate. (A) The process is
A step of preparing a resin sheet including a support and a resin composition layer provided on the support and containing a resin composition;
a step of laminating a resin sheet on the inner layer substrate so that the resin composition layer is bonded to the inner layer substrate, and
The method for manufacturing a printed wiring board according to claim 1 or 2 , comprising the step of thermosetting the resin composition layer on the inner layer substrate. The method for manufacturing a printed wiring board according to claim 2 or 3 , wherein the resin composition contains a phenolic curing agent. The method for producing a printed wiring board according to any one of claims 2 to 4 , wherein the resin composition contains an active ester curing agent. The method for manufacturing a printed wiring board according to any one of claims 2 to 5 , wherein the maximum thickness of the resin composition layer is 100 μm. The method for manufacturing a printed wiring board according to any one of claims 1 to 6 , wherein the aqueous liquid is water. The method for manufacturing a printed wiring board according to any one of claims 1 to 7 , further comprising the step of (G) washing the surface of the insulating layer with water at a temperature below 35°C.

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