JP2020074475A - Manufacturing method of print circuit board and manufacturing method of semiconductor device - Google Patents

Abstract

To provide a manufacturing method of print circuit board capable of forming an isolating layer exhibiting high adhesion to a conductor layer with low relative roughness, and is excellent in smear removability.SOLUTION: A manufacturing method of print circuit board includes (A) a step of laminating a resin sheet with a support medium, including the support medium and a resin composition layer bonded to the support medium, on an inner layer circuit board so that the resin composition layer is bonded to the inner layer circuit board,(B) a step of forming an isolating layer by thermally hardening the resin composition layer of the resin sheet with a support medium, (C) a step of forming a via hole by boring the isolating layer, (D) a step of performing desmear treatment, (E) a step of exfoliating the support medium, and (F) a step of forming a conductor layer on the surface of the isolating layer, in this order.SELECTED DRAWING: None

Description

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

  Printed wiring boards, which are widely used in various electronic devices, are required to have thinner layers and finer wiring for circuits in order to make electronic devices smaller and more sophisticated. As a manufacturing technique of a printed wiring board, a manufacturing method by a build-up method in which insulating layers and conductor layers are alternately stacked on an inner layer circuit board is known. In the manufacturing method by the build-up method, the insulating layer is formed by laminating the resin composition layer on the inner layer circuit board using, for example, an adhesive film having the resin composition layer, and thermosetting the resin composition layer. .. Next, a hole is formed in the formed insulating layer to form a via hole, and a desmear process is performed to simultaneously remove the resin residue (smear) inside the via hole and roughen the insulating layer surface (for example, , Patent Document 1).

JP, 2008-37957, A

  In the build-up manufacturing method, the conductor layer is formed on the surface of the insulating layer after the desmear treatment. At this time, if the unevenness of the insulating layer surface after desmearing is large, it will hinder fine wiring, so the roughness of the insulating layer surface should be kept low as long as sufficient adhesion strength with the conductor layer can be realized. Is desirable. For example, the roughness of the surface of the insulating layer can be suppressed low by forming the insulating layer using a resin composition having high resistance to desmear treatment. However, with such a method, the smear removability inside the via hole (particularly the bottom of the via hole) is also reduced.

  On the other hand, if relatively strong desmear processing conditions are adopted in order to improve the smear removability, the roughness of the surface of the insulating layer becomes high, which is disadvantageous in forming fine wiring. Not only that, when the insulating layer is formed using a resin composition having a high inorganic filler content, the adhesion strength between the insulating layer and the conductor layer is high even though the surface roughness of the insulating layer is high. It was found to tend to decline.

  The present invention has been made in view of the above circumstances, and a problem to be solved by the present invention is to form an insulating layer having a high adhesion strength with a conductor layer while having a low roughness, and to remove smear. Another object of the present invention is to provide an excellent printed wiring board manufacturing method.

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

That is, the present invention includes the following contents.
[1] A resin sheet with a support including (A) a support and a resin composition layer that is bonded to the support is laminated on the inner layer circuit board so that the resin composition layer is bonded to the inner layer circuit board. Process,
(B) a step of thermosetting the resin composition layer of the resin sheet with a support to form an insulating layer,
(C) A step of forming a via hole by forming a hole in the insulating layer,
(D) Desmearing process,
A method for manufacturing a printed wiring board, which includes (E) a step of peeling the support and (F) a step of forming a conductor layer on the surface of the insulating layer in this order.
[2] The method for producing a printed wiring board according to [1], wherein the desmear treatment in the step (D) is a wet desmear treatment, a dry desmear treatment, or a combination thereof.
[3] The step (F) is
The method for producing a printed wiring board according to [1] or [2], which comprises roughening the surface of the insulating layer and wet-plating the surface of the insulating layer to form a conductor layer in this order.
[4] The step (F) is
The printed wiring according to [1] or [2], which includes, in this order, dry plating on the surface of the insulating layer to form a metal layer, and wet plating on the surface of the metal layer to form a conductor layer. Method of manufacturing a plate.
[5] The method for producing a printed wiring board according to any one of [1] to [4], wherein the resin composition layer of the resin sheet with a support contains an epoxy resin, a curing agent and an inorganic filler.
[6] The method for producing a printed wiring board according to [5], wherein the curing agent contains an active ester curing agent.
[7] The method for producing a printed wiring board according to [5] or [6], wherein the inorganic filler has an average particle diameter of 0.01 μm to 3 μm.
[8] The content of the inorganic filler in the resin composition layer is 40% by mass to 95% by mass when the nonvolatile component of the resin composition layer is 100% by mass. The method for manufacturing a printed wiring board according to any one of claims.
[9] The method for manufacturing a printed wiring board according to any one of [5] to [8], wherein the inorganic filler is surface-treated with a surface treatment agent.
[10] A printed wiring board manufactured by the method according to any one of [1] to [9].
[11] A semiconductor device including the printed wiring board according to [10].

  According to the present invention, it is possible to provide a method for producing a printed wiring board which has a low roughness and can form an insulating layer having a high adhesion strength with a conductor layer and which is also excellent in smear removability.

  Hereinafter, the present invention will be described in detail with reference to its preferred embodiments.

[Method for manufacturing printed wiring board]
The method for manufacturing a printed wiring board of the present invention includes the following steps (A) to (F) in this order.
(A) A step of laminating a resin sheet with a support including a support and a resin composition layer to be bonded to the support on an inner layer circuit board so that the resin composition layer is bonded to the inner layer circuit board (B) ) A step of thermosetting the resin composition layer of the resin sheet with a support to form an insulating layer (C) A step of forming a via hole by punching the insulating layer (D) A step of performing a desmearing treatment (E) a support (F) Step of forming conductor layer on surface of insulating layer

In the present invention, the term “including in this order” as to the steps (A) to (F) includes the steps (A) to (F) and the steps (A) to (F). It does not prevent inclusion of other steps as long as they are performed in this order.
Hereinafter, the same applies to "including in this order" of steps or treatments.

<Resin sheet with support>
Before describing each step in detail, the resin sheet with a support used in the manufacturing method of the present invention will be described.

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

(Support)
Examples of the support include a film made of a plastic material, a metal foil (copper foil, aluminum foil, etc.) and a release paper, and a film made of a plastic material is preferably used. Examples of the plastic material include polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as “PET”) and polyethylene naphthalate (hereinafter sometimes abbreviated as “PEN”), polycarbonate (hereinafter referred to as “PC”). Abbreviated), acrylic such as polymethylmethacrylate (PMMA), cyclic polyolefin, triacetyl cellulose (TAC), polyether sulfide (PES), polyether ketone, and polyimide. Among them, polyethylene terephthalate and polyethylene naphthalate are preferable, and inexpensive polyethylene terephthalate is particularly preferable. In a preferred embodiment, the support is a polyethylene terephthalate film.

  The support may have a matte treatment or a corona treatment on the surface to be joined to the resin composition layer.

  Further, as the support, a support with a release layer having a release layer on the surface to be joined with the resin composition layer may be used. Examples of the release agent used in the release layer of the support with release layer include one or more release agents selected from the group consisting of alkyd resin, polyolefin resin, urethane resin, and silicone resin. ..

  In the present invention, a commercially available product may be used as the support with the release layer. Examples of commercially available products include "SK-1", "AL-5", and "AL-7" manufactured by Lintec Co., Ltd., which are PET films having a release layer containing an alkyd resin-based release agent as a main component. And the like.

  The thickness of the support is not particularly limited, but is preferably in the range of 10 μm to 70 μm, more preferably in the range of 20 μm to 60 μm. When the support is a support with a release layer, the total thickness of the support with a release layer is preferably within the above range.

(Resin composition layer)
The resin composition used for the resin composition layer is not particularly limited as long as the cured product has sufficient hardness and insulation. For example, a resin composition containing (a) epoxy resin, (b) curing agent, and (c) inorganic filler can be used. The resin composition used for the resin composition layer may further contain additives such as a thermoplastic resin, a curing accelerator, a flame retardant, and rubber particles, if necessary.

  In addition, in this invention, the content of each component which comprises a resin composition is a value when the total of the non-volatile component in a resin composition is set to 100 mass%.

(A) Epoxy resin Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol epoxy resin, naphthol novolac. Epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthalene type epoxy resin, naphthol type epoxy resin, anthracene type epoxy resin, glycidyl amine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin , Biphenyl type epoxy resin, linear aliphatic epoxy resin, epoxy resin having butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, Pyro ring-containing epoxy resins, cyclohexanedimethanol type epoxy resins, naphthylene ether type epoxy resins and trimethylol type epoxy resins. The epoxy resins may be used alone or in combination of two or more.

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

  As the liquid epoxy resin, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a phenol novolac type epoxy resin, or a naphthalene type epoxy resin is preferable, and a naphthalene type epoxy resin is more preferable. Specific examples of the liquid epoxy resin include "EXA4032SS" (naphthalene type epoxy resin), "HP4032" (naphthalene type epoxy resin), "HP4032D" (naphthalene type epoxy resin) manufactured by DIC Corporation, Mitsubishi Chemical Corporation. "JER828EL" (bisphenol A type epoxy resin), "jER807" (bisphenol F type epoxy resin), "jER152" (phenol novolac type epoxy resin), Nippon Steel Chemical Co., Ltd. "ZX1059" (bisphenol A) Type epoxy resin and bisphenol F type epoxy resin) and the like. These may be used alone or in combination of two or more.

  As the solid epoxy resin, tetrafunctional naphthalene type epoxy resin, cresol novolac type epoxy resin, dicyclopentadiene type epoxy resin, trisphenol epoxy resin, naphthol novolac epoxy resin, biphenyl type epoxy resin, or naphthylene ether type epoxy resin can be used. A tetrafunctional naphthalene type epoxy resin, a biphenyl type epoxy resin, or a naphthylene ether type epoxy resin is more preferable. Specific examples of the solid epoxy resin include "HP-4700" (tetrafunctional naphthalene type epoxy resin), "N-690" (cresol novolac type epoxy resin) and "N-695" (cresol) manufactured by DIC Corporation. Novolac type epoxy resin), "HP-7200" (dicyclopentadiene type epoxy resin), "EXA7311" (naphthylene ether type epoxy resin), "EXA7310" (naphthylene ether type epoxy resin), "EXA7311-G3" ( Naphthylene ether type epoxy resin), "EPPN-502H" (Trisphenol epoxy resin) manufactured by Nippon Kayaku Co., Ltd., "NC7000L" (naphthol novolac epoxy resin), "NC3000H" (biphenyl type epoxy resin), "NC3000". "(Biphenyl type epoxy resin , "NC3000L" (biphenyl type epoxy resin), "NC3100" (biphenyl type epoxy resin), "ESN475" (Naphthol novolac type epoxy resin) manufactured by Tohto Kasei Co., Ltd., "ESN485" (naphthol novolac type epoxy resin), Examples include "ESN475V" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical Co., Ltd., "YX4000H" (biphenyl type epoxy resin) and "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation. Be done.

  When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, their amount ratio (liquid epoxy resin: solid epoxy resin) is in the range of 1: 0.1 to 1: 5 by mass ratio. preferable. By setting the amount ratio of the liquid epoxy resin and the solid epoxy resin in such a range, i) appropriate adhesiveness is brought about when used in the form of a resin sheet, ii) when used in the form of a resin sheet Sufficient flexibility is obtained, handleability is improved, and iii) a cured product having sufficient breaking strength can be obtained. From the viewpoint of the above effects i) to iii), the amount ratio of the liquid epoxy resin and the solid epoxy resin (liquid epoxy resin: solid epoxy resin) is 1: 0.3 to 1: 4.5 by mass ratio. Is more preferable, and the range of 1: 0.6 to 1: 4 is further preferable.

  3 mass% -35 mass% are preferable, as for content of the epoxy resin in a resin composition, 5 mass% -30 mass% are more preferable, 5 mass% -25 mass% are more preferable, 7 mass% -20 mass%. % Is particularly preferred.

(B) Curing agent The curing agent is not particularly limited as long as it has a function of curing an epoxy resin, but examples thereof include a phenolic curing agent, a naphthol curing agent, an active ester curing agent, a benzoxazine curing agent, and a cyanate. Ester-based curing agents may be mentioned. The curing agents may be used alone or in combination of two or more.

  As the phenol-based curing agent and the naphthol-based curing agent, a phenol-based curing agent having a novolac structure or a naphthol-based curing agent having a novolac structure is preferable from the viewpoint of heat resistance and water resistance. From the viewpoint of adhesion strength with the conductor layer, a nitrogen-containing phenol-based curing agent is preferable, and a triazine skeleton-containing phenol-based curing agent is more preferable. Above all, from the viewpoint of highly satisfying the heat resistance, the water resistance, and the adhesion strength with the conductor layer, it is preferable to use the triazine skeleton-containing phenol novolac resin as the curing agent.

  Specific examples of the phenol-based curing agent and the naphthol-based curing agent include, for example, "MEH-7700", "MEH-7810", "MEH-7851" manufactured by Meiwa Kasei Co., Ltd., manufactured by Nippon Kayaku Co., Ltd. "NHN", "CBN", "GPH", "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN375", "SN395" manufactured by Tohto Kasei Co., Ltd. , "LA7052", "LA7054", "LA3018", "LA1356" and the like manufactured by DIC Corporation.

  An active ester-based curing agent is also preferable from the viewpoint of increasing the adhesion strength with the conductor layer. The active ester curing agent also has the effect of suppressing the roughness of the surface of the insulating layer after roughening to a low level. That is, the active ester-based curing agent can bring about an insulating layer having a low roughness and a high adhesion strength with the conductor layer. As described above, the active ester type curing agent has an excellent effect, but on the other hand, it also has a problem that it results in a resin residue (smear) which is difficult to remove in the desmear treatment. Although it is possible to remove smear by adopting a relatively strong desmear treatment condition, in that case, the roughness of the surface of the insulating layer becomes high, and the active ester curing agent is essentially The excellent effect to be played will be diminished.

  Although details will be described later, according to the method for producing a printed wiring board of the present invention, it is possible to improve smear removability while maintaining the low roughness of the insulating layer surface, and the active ester curing agent is essentially Advantageous effects can be enjoyed.

  The active ester-based curing agent is not particularly limited, but in general, an ester group having a high reaction activity such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds is contained in one molecule. Compounds having two or more of them are preferably used. The active ester type curing agent is preferably obtained by a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. Particularly, from the viewpoint of improving heat resistance, an active ester type curing agent obtained from a carboxylic acid compound and a hydroxy compound is preferable, and an active ester type curing agent obtained from a carboxylic acid compound and a phenol compound and / or a naphthol compound is more preferable. Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid and pyromellitic acid. Examples of the phenol compound or naphthol compound include hydroquinone, resorcin, bisphenol A, bisphenol F, bisphenol S, phenolphthaline, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m- Cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, Examples thereof include benzenetriol, dicyclopentadienyl diphenol, and phenol novolac.

  Examples of the active ester curing agent include an active ester compound containing a dicyclopentadienyl diphenol structure, an active ester compound containing a naphthalene structure, an active ester compound containing an acetylated product of phenol novolac, and an active ester containing a benzoylated product of phenol novolac. A compound is preferable, and among them, an active ester compound containing a naphthalene structure and an active ester compound containing a dicyclopentadienyldiphenol structure are more preferable.

  Commercially available active ester curing agents include "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T" (DIC Corporation) as active ester compounds containing a dicyclopentadienyldiphenol structure. Manufactured by Mitsubishi Chemical Co., Ltd.), “EXB9416-70BK” (manufactured by DIC Corporation) as an active ester compound containing a naphthalene structure, “DC808” (manufactured by Mitsubishi Chemical Corporation) as an active ester compound containing an acetylated product of phenol novolac, and phenol novolac "YLH1026" (made by Mitsubishi Chemical Corporation) etc. are mentioned as an active ester compound containing a benzoyl compound.

  Specific examples of the benzoxazine-based curing agent include "HFB2006M" manufactured by Showa Highpolymer Co., Ltd., "Pd" and "Fa" manufactured by Shikoku Chemicals Co., Ltd.

  Examples of the cyanate ester-based 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) phenyl propane, 1,1-bis (4-cyanate phenylmethane), bis (4-cyanate-3,5-dimethyl) Phenyl) methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, and bifunctional cyanate resin such as bis (4-cyanatephenyl) ether, phenol Novolak and black Examples thereof include polyfunctional cyanate resins derived from sol novolac, prepolymers obtained by partially converting these cyanate resins into triazine, etc. Specific examples of the cyanate ester-based curing agent include "PT30" manufactured by Lonza Japan Co., Ltd. and Examples thereof include "PT60" (all of which are phenol novolac type polyfunctional cyanate ester resins), "BA230" (a prepolymer in which a part or all of bisphenol A dicyanate is triazined to be a trimer).

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

  As described above, it is preferable that the curing agent contains an active ester curing agent from the viewpoint of obtaining an insulating layer having a low roughness and a high adhesion strength with the conductor layer. The ratio of the active ester type curing agent in the entire curing agent is preferably 10% or more, more preferably 30% or more, further preferably 50% or more, particularly preferably 60% or more, based on the number of reactive groups of the curing agent. preferable. The upper limit of the ratio is not particularly limited and may be 100%, but from the viewpoint of improving curing reactivity, 90% or less is preferable, and 80% or less is more preferable. When a mixture of an active ester curing agent and another curing agent is used as the curing agent, the other curing agent has low roughness and high adhesion strength with the conductor layer while obtaining the pot life of the composition. From the viewpoint of realizing an insulating layer, a phenol type curing agent and a naphthol type curing agent are preferable.

(C) Inorganic filler Examples of the inorganic filler include silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride and boric acid. Examples thereof include aluminum, barium titanate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate. Among these, silica such as amorphous silica, fused silica, crystalline silica, synthetic silica and hollow silica is particularly preferable. Further, spherical silica is preferable as the silica. The inorganic fillers may be used alone or in combination of two or more. Examples of commercially available spherical fused silica include "SOC2" and "SOC1" manufactured by Admatechs Co., Ltd.

  The average particle size of the inorganic filler is preferably 0.01 μm to 3 μm, more preferably 0.05 μm to 2 μm, further preferably 0.1 μm to 1 μm, and 0.3 μm to 0.8 μm. Particularly preferred. The average particle diameter of the inorganic filler can be measured by a laser diffraction / scattering method based on the Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis by a laser diffraction / scattering particle size distribution measuring device, and the median diameter can be used as the average particle diameter for measurement. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As the laser diffraction / scattering particle size distribution measuring device, LA-500 manufactured by Horiba, Ltd. can be used.

  The inorganic filler is one kind of an aminosilane coupling agent, an epoxysilane coupling agent, a mercaptosilane coupling agent, a silane coupling agent, an organosilazane compound, a titanate coupling agent, etc. for improving the moisture resistance. Alternatively, it is preferably treated with two or more surface treatment agents. Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd. and "KBM803" (3-mercaptopropyltrimethoxy manufactured by Shin-Etsu Chemical Co., Ltd.). Silane), Shin-Etsu Chemical Co., Ltd. "KBE903" (3-aminopropyltriethoxysilane), Shin-Etsu Chemical Co., Ltd. "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), Shin-Etsu Chemical Co., Ltd. "SZ-31" (hexamethyldisilazane) manufactured by Co., Ltd. and the like can be mentioned.

  Further, the amount of carbon per unit surface area of the inorganic filler after the surface treatment with the surface treatment agent is washed with a solvent (for example, methyl ethyl ketone (MEK)) can be measured. Specifically, a sufficient amount of MEK as a solvent is added to the inorganic filler surface-treated with the surface treatment agent, and ultrasonic cleaning is performed at 25 ° C. for 5 minutes. After removing the supernatant and drying the solid content, the carbon amount 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. can be used.

Carbon content per unit surface area of the inorganic filler, from the viewpoint of improving dispersibility of the inorganic filler is preferably 0.02 mg / ^{m 2} or more, 0.1 mg / ^{m 2} or more preferably, 0.2 mg / ^{m 2} The above is more preferable. On the other hand, 1 mg / m ² or less is preferable, 0.8 mg / m ² or less is more preferable, and 0.5 mg / m ² or less is from the viewpoint of preventing the melt viscosity of the resin varnish and the melt viscosity in the sheet form from increasing. More preferable.

  As described above, the present inventors have found that when forming an insulating layer using a resin composition having a high inorganic filler content, the adhesion strength between the insulating layer and the conductor layer is likely to decrease. However, according to the method for producing a printed wiring board of the present invention, sufficient adhesion strength between the insulating layer and the conductor layer can be realized even when a resin composition having a high inorganic filler content is used.

  The content of the inorganic filler in the resin composition is 40 mass from the viewpoint of reducing the coefficient of thermal expansion of the insulating layer and preventing the occurrence of cracks and circuit distortion due to the difference in thermal expansion between the insulating layer and the conductor layer. % Or more, 50% by mass or more is more preferable, 60% by mass or more is further preferable, and 65% by mass or more is particularly preferable.

  In the method for producing a printed wiring board of the present invention, the content of the inorganic filler in the resin composition can be further increased without lowering the adhesion strength between the insulating layer and the conductor layer. For example, the content of the inorganic filler in the resin composition may be increased to 66% by mass or more, 68% by mass or more, 70% by mass or more, 72% by mass or more, or 74% by mass or more.

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

  In one embodiment, the resin composition used for the resin composition layer includes the above-mentioned (a) epoxy resin, (b) curing agent, and (c) inorganic filler. Among them, the resin composition is a mixture of liquid epoxy resin and solid epoxy resin as (a) epoxy resin (the liquid epoxy resin: solid epoxy resin mass ratio is preferably 1: 0.1 to 1: 5, Preferably 1: 0.3 to 1: 4.5, more preferably 1: 0.6 to 1: 4) (b) as an active ester curing agent, phenolic curing agent and naphthol curing agent It is preferable that at least one selected from the group consisting of (c) silica is contained as the inorganic filler. From the viewpoint that an insulating layer having a low roughness and a high adhesion strength with a conductor layer can be more advantageously formed, (a) a mixture of a liquid epoxy resin and a solid epoxy resin (liquid epoxy resin: solid epoxy resin The mass ratio is preferably 1: 0.1 to 1: 5, more preferably 1: 0.3 to 1: 4.5, further preferably 1: 0.6 to 1: 4), and (b) a curing agent. It is more preferable to include a curing agent containing an active ester curing agent as the above, and silica as the inorganic filler (c). Also for the resin composition layer containing a combination of such specific components, suitable contents of the (a) epoxy resin, the (b) curing agent, and the (c) inorganic filler are as described above. It is preferable that the content of the (a) epoxy resin is 3% by mass to 35% by mass, the content of the (c) inorganic filler is 40% by mass to 90% by mass, and the content of the (a) epoxy resin is 5%. It is more preferable that the content of the inorganic filler is 50% by mass to 25% by mass and the content of the inorganic filler (c) is 50% by mass to 90% by mass. Regarding the content of the curing agent (b), the ratio of the total number of epoxy groups of the epoxy resin (a) to the total number of reactive groups of the curing agent (b) is 1: 0.2 to 1: 2. It is preferable to contain it so that it becomes 1: 0.3 to 1: 1.5, and it is more preferable to contain it so that it becomes 1: 0.4 to 1: 1. ..

  The resin composition used for the resin composition layer may further contain additives such as a thermoplastic resin, a curing accelerator, a flame retardant, and rubber particles, if necessary.

  Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyether sulfone resin, and polysulfone resin. The thermoplastic resins may be used alone or in combination of two or more.

  The polystyrene-equivalent weight average molecular weight of the thermoplastic resin is preferably in the range of 8,000 to 70,000, more preferably in the range of 10,000 to 60,000, and even more preferably in the range of 20,000 to 60,000. The polystyrene equivalent weight average molecular weight of the thermoplastic resin is measured by gel permeation chromatography (GPC) method. Specifically, the polystyrene-equivalent weight average molecular weight of the thermoplastic resin is LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P / K-manufactured by Showa Denko KK as a column. 804L / K-804L can be calculated by using chloroform or the like as a mobile phase at a column temperature of 40 ° C. and using a calibration curve of standard polystyrene.

  Examples of the phenoxy resin 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, terpene. Examples include phenoxy resins having one or more skeletons selected from the group consisting of a skeleton and a trimethylcyclohexane skeleton. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group and an epoxy group. The phenoxy resin may be used alone or in combination of two or more. Specific examples of the phenoxy resin include "1256" and "4250" (both bisphenol A skeleton-containing phenoxy resins) manufactured by Mitsubishi Chemical Corporation, "YX8100" (bisphenol S skeleton-containing phenoxy resin), and "YX6954" ( Bisphenol acetophenone skeleton-containing phenoxy resin), and in addition, "FX280" and "FX293" manufactured by Tohto Kasei Co., Ltd., "YL7553", "YL6794", "YL7213", and "YL7213" manufactured by Mitsubishi Chemical Corporation. Examples thereof include “YL7290” and “YL7482”.

  Specific examples of the polyvinyl acetal resin include electrified butyral 4000-2, 5000-A, 6000-C, 6000-EP manufactured by Denki Kagaku Kogyo Co., Ltd., S-REC BH series, BX series manufactured by Sekisui Chemical Co., Ltd., KS series, BL series, BM series and the like can be mentioned.

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

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

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

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

  The content of the thermoplastic resin in the resin composition is preferably 0.1% by mass to 20% by mass. By setting the content of the thermoplastic resin in such a range, the viscosity of the resin composition becomes appropriate and a resin composition having a uniform thickness and bulk properties can be formed. The content of the thermoplastic resin in the resin composition is more preferably 0.5% by mass to 10% by mass.

  Examples of the curing accelerator include organic phosphine compounds, imidazole compounds, amine adduct compounds, and tertiary amine compounds. The content of the curing accelerator is preferably in the range of 0.05% by mass to 3% by mass, when the total of the nonvolatile components of the (a) epoxy resin and the (b) curing agent is 100% by mass. The curing accelerator may be used alone or in combination of two or more.

  Examples of the flame retardant include organic phosphorus flame retardants, organic nitrogen-containing phosphorus compounds, nitrogen compounds, silicone flame retardants, metal hydroxides, and the like. The flame retardants may be used alone or in combination of two or more. The content of the flame retardant in the resin composition is not particularly limited, but is preferably 0.5% by mass to 10% by mass, more preferably 1% by mass to 9% by mass, and further preferably 1% by mass to 8% by mass. ..

  As the rubber particles, for example, those which are insoluble in a solvent described later and are incompatible with the above-mentioned epoxy resin, curing agent, thermoplastic resin, etc. are used. Such rubber particles are generally prepared by increasing the molecular weight of the rubber component to a level at which the rubber component does not dissolve in the solvent or the resin and forming the rubber particles.

  Examples of the rubber particles include core-shell type rubber particles, crosslinked acrylonitrile butadiene rubber particles, crosslinked styrene butadiene rubber particles and acrylic rubber particles. The core-shell type rubber particles are rubber particles having a core layer and a shell layer, for example, a two-layer structure in which the outer shell layer is composed of a glassy polymer and the inner core layer is composed of a rubbery polymer, or Examples include a three-layer structure in which the outer shell layer is composed of a glassy polymer, the intermediate layer is composed of a rubbery polymer, and the core layer is composed of a glassy polymer. The glassy polymer layer is composed of, for example, a methyl methacrylate polymer, and the rubbery polymer layer is composed of, for example, a butyl acrylate polymer (butyl rubber). The rubber particles may be used alone or in combination of two or more.

  The average particle size of the rubber particles is preferably in the range of 0.005 μm to 1 μm, more preferably in the range of 0.2 μm to 0.6 μm. The average particle size of the rubber particles can be measured using a dynamic light scattering method. For example, rubber particles are uniformly dispersed in an appropriate organic solvent by ultrasonic waves, etc., and a particle size distribution of rubber particles is prepared on a mass basis using a concentrated particle size analyzer (FPAR-1000; manufactured by Otsuka Electronics Co., Ltd.). However, it can be measured by setting the median diameter to the average particle diameter. The content of the rubber particles in the resin composition is preferably 1% by mass to 10% by mass, more preferably 2% by mass to 5% by mass.

  The resin composition used for the resin composition layer may contain other additives, if necessary. Such other additives include, for example, organocopper compounds, organometallic compounds such as organozinc compounds and organocobalt compounds, and organic fillers, thickeners, defoamers, leveling agents, adhesion promoters, colorants. And resin additives such as curable resins.

  In the resin sheet with a support, the thickness of the resin composition layer is preferably 3 μm to 100 μm, more preferably 5 μm to 80 μm, and further preferably 20 μm to 60 μm.

  In the resin sheet with a support, the resin composition layer may have a multilayer structure composed of two or more layers. When a resin composition layer having a multilayer structure is used, the total thickness is preferably within the above range.

  The resin sheet with a support can be produced by forming a resin composition layer on the support.

  The resin composition layer can be formed on the support by a known method. For example, a resin varnish prepared by dissolving a resin composition in a solvent is prepared, and the resin varnish is applied to the surface of a support by using a coating device such as a die coater, and the resin varnish is dried to form a resin composition layer. be able to.

  The solvent used for the preparation of the resin varnish, for example, acetone, ketone solvents such as methyl ethyl ketone and cyclohexanone, ethyl acetate, butyl acetate, cellosolve acetate, acetic acid ester solvents such as propylene glycol monomethyl ether acetate and carbitol acetate, cellosolve and Carbitol solvents such as butyl carbitol, aromatic hydrocarbon solvents such as toluene and xylene, amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone, and the like can be mentioned. The solvent may be used alone or in combination of two or more.

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

  In the resin sheet with a support, a protective film conforming to the support can be further laminated on the surface of the resin composition layer that is not bonded to the support (that is, 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 prevent scratches. The resin sheet with a support can be wound into a roll and stored, and can be used by peeling off the protective film when manufacturing a printed wiring board.

  Such a resin sheet with a support is useful as an insulating layer of a printed wiring board, particularly as an interlayer insulating layer, since it has a low roughness and results in an insulating layer having excellent adhesion strength with a conductor layer.

  Hereinafter, each step will be described.

<Process (A)>
In the step (A), a resin sheet with a support including a support and a resin composition layer to be bonded to the support is laminated on the inner layer circuit board so that the resin composition layer is bonded to the inner layer circuit board. ..

  The structure of the resin sheet with a support used in the step (A) is as described above. The "inner layer circuit board" means a conductor layer (circuit) patterned on one or both sides of a board such as a glass epoxy board, a metal board, a polyester board, a polyimide board, a BT resin board, and a thermosetting polyphenylene ether board. And an intermediate product on which an insulating layer and a conductor layer are to be further formed when manufacturing a printed wiring board.

  The lamination of the resin sheet with a support and the inner layer circuit board in the step (A) may be carried out by any conventionally known method, but the resin composition layer of the resin sheet with a support may be formed by roll pressure bonding or press pressure bonding. It is preferable to carry out a laminating process so as to be bonded to the inner layer circuit board. Among them, the vacuum laminating method of laminating under reduced pressure is more preferable. The laminating method may be a batch type or a continuous type.

Lamination, in general, the bonding pressure in the range of ^{1kgf / cm 2 ~11kgf / cm 2} (0.098MPa~1.078MPa), the compression temperature in the range of 70 ° C. to 120 ° C., a pressure bonding time of 5 seconds to 180 It is preferable to carry out under a reduced pressure of 20 mmHg (26.7 hPa) or less within a range of 2 seconds.

  The laminating treatment can be carried out using a commercially available vacuum laminator. Examples of the commercially available vacuum laminator include a vacuum pressure laminator manufactured by Meiki Seisakusho Co., Ltd. and a vacuum applicator manufactured by Nichigo Morton Co., Ltd.

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

<Process (B)>
In the step (B), the resin composition layer of the resin sheet with a support is thermoset to form an insulating layer.

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

  For example, the thermosetting conditions of the resin composition layer vary depending on the type of the resin composition and the like, but the curing temperature is in the range of 120 ° C to 240 ° C (preferably 150 ° C to 210 ° C, more preferably 170 ° C). The curing time can be set to 5 minutes to 90 minutes (preferably 10 minutes to 75 minutes, more preferably 15 minutes to 60 minutes).

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

<Process (C)>
In step (C), a hole is formed in the insulating layer to form a via hole.

  The via hole is provided for electrical connection between the layers, and can be formed by a known method using a drill, a laser, plasma or the like in consideration of the characteristics of the insulating layer. For example, a laser beam can be irradiated from above the support to form a via hole in the insulating layer. The size of the opening of the via hole is selected depending on the fineness of the mounted component, but the top diameter is preferably in the range of 40 μm to 500 μm.

  Examples of the laser light source include carbon dioxide gas laser, YAG laser, excimer laser and the like. Of these, a carbon dioxide gas laser is preferable from the viewpoint of processing speed and cost.

  When a carbon dioxide laser device is used as the laser light source, laser light having a wavelength of 9.3 μm to 10.6 μm is generally used. Although the number of shots varies depending on the depth and diameter of the via hole to be formed, it is usually selected in the range of 1 to 10 shots. From the viewpoint of increasing the processing speed to improve the productivity of the printed wiring board, 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. When the number of shots is two or more, the laser light may be emitted in any of the burst mode and the cycle mode.

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

  The drilling process can be performed using a commercially available laser device. Examples of commercially available carbon dioxide laser devices include LC-2E21B / 1C manufactured by Hitachi Via Mechanics Co., Ltd., ML605GTWII manufactured by Mitsubishi Electric Corporation, and a substrate drilling laser machine manufactured by Matsushita Welding System Co., Ltd. Can be mentioned.

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

  Generally, a resin residue (smear) adheres to the inside of the via hole (particularly the bottom of the via hole) formed in the step (C). Since such smear causes a poor electrical connection between layers, a process (desmear process) for removing the smear is performed in the step (D).

  In the method for manufacturing a multilayer printed wiring board according to the present invention, the desmear treatment is performed with the support attached to the insulating layer. Unlike the prior art in which desmear treatment is performed after peeling the support, the surface of the insulating layer is protected by the support, so the smear inside the via hole is removed without roughening the surface of the insulating layer. be able to. Further, since there is no restriction that the surface of the insulating layer is damaged, a wide range of desmear processing methods and desmear processing conditions can be adopted. As a result, even when a resin composition containing an active ester-based curing agent that results in a resin residue (smear) that is difficult to remove in the desmear treatment is used as the resin composition for forming the insulating layer, the insulating layer The smear can be effectively removed without increasing the surface roughness.

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

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

  The desmear processing using plasma can be implemented using a commercially available plasma desmear processing apparatus. Among commercially available plasma desmear processing apparatuses, examples suitable for manufacturing printed wiring boards include a microwave plasma apparatus manufactured by Nissin Co., Ltd. and an atmospheric pressure plasma etching apparatus manufactured by Sekisui Chemical Co., Ltd.

  As the dry desmearing treatment, a dry sandblasting treatment may be used in which an abrasive is sprayed from a nozzle to polish an object to be treated. The dry sandblasting treatment can be carried out using a commercially available dry sandblasting apparatus. When a water-soluble abrasive is used as the abrasive, the smear can be effectively removed by the dry sandblasting treatment followed by the water washing treatment without the abrasive remaining inside the via hole.

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

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

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

<Process (E)>
In the step (E), the support is peeled off. As a result, the surface of the insulating layer is exposed.

  The support may be peeled manually or mechanically with an automatic peeling device. When a metal foil is used as the support, the metal foil may be removed by etching with an etching solution.

  Since the surface of the insulating layer was protected by the support during the desmear treatment in the step (D), the surface of the insulating layer exposed in this step advantageously has a low roughness (for the value of the roughness of the surface of the insulating layer). Will be described later.).

<Process (F)>
In the step (F), a conductor layer is formed on the surface of the insulating layer.

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

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

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

  The conductor layer can be formed on the surface of the insulating layer by using various conventionally known methods such as a full additive method and a semi-additive method.

In one embodiment, step (F) comprises
Roughening treatment of the surface of the insulating layer and wet plating on the surface of the insulating layer to form a conductor layer are included in this order (hereinafter, such a step is referred to as “step (F-1)”). ..

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

  The dry roughening treatment can be performed in the same manner as the dry desmear treatment described above. The wet roughening treatment can be performed in the same manner as the wet desmear treatment described above.

  When the dry roughening treatment and the wet roughening treatment are performed in combination, the dry roughening treatment may be performed first or the wet roughening treatment may be performed first.

  Although such a roughening treatment is intended to roughen the exposed surface of the insulating layer, it also has a certain effect in removing smear inside the via hole. Therefore, even when the step (D) is performed under mild conditions, it is possible to prevent the smear from remaining.

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

  For example, the conductor layer having a desired wiring pattern can be formed by wet plating on the surface of the insulating layer by a conventionally known technique such as a semi-additive method or a full-additive method. Hereinafter, an example of forming the conductor layer by the semi-additive method will be described.

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

In another embodiment, step (F) comprises
This order includes dry plating on the surface of the insulating layer to form a metal layer, and wet plating on the surface of the metal layer to form a conductor layer (hereinafter, such a step is referred to as “step (F-2 ) ”.).

  In the step (F-2), first, the surface of the insulating layer is dry-plated to form a metal layer. Examples of dry plating include physical vapor deposition (PVD) methods such as vacuum vapor deposition, sputtering, ion plating, and laser ablation, and chemical vapor deposition (CVD) methods such as thermal CVD and plasma CVD. , Sputtering is preferred. The metal layer may be formed by combining these two types of dry plating.

  Then, the formed metal layer is used as a plating seed layer, and the metal layer can be wet-plated by a semi-additive method to form a conductor layer.

In the step (F-2), sufficient adhesion strength between the insulating layer and the conductor layer can be achieved without roughening the surface of the insulating layer, but the surface of the insulating layer is roughened. May be. In this case, the step (F-2) is
Roughening the surface of the insulating layer,
This step includes dry-plating the surface of the insulating layer to form the metal layer, and wet-plating the surface of the metal layer to form the conductor layer.

  INDUSTRIAL APPLICABILITY The method for manufacturing a printed wiring board of the present invention can form an insulating layer (interlayer insulating layer) having a low degree of roughness and a high adhesion strength with a conductor layer, and exhibits excellent smear removability. Therefore, the method for manufacturing a printed wiring board of the present invention significantly contributes to fine wiring of the printed wiring board without causing electrical connection failure between layers.

[Printed wiring board]
Regarding the printed wiring board manufactured by the method of the present invention, the arithmetic mean roughness (Ra) of the surface of the insulating layer is preferably 180 nm or less, more preferably 140 nm or less, and 100 nm or less. More preferably, it is 90 nm or less, 80 nm or less, 70 nm or less, or 60 nm or less. The lower limit of Ra value is not particularly limited, but is preferably 0.5 nm or more, more preferably 1 nm or more. Further, the root mean square roughness (Rq) of the surface of the insulating layer is preferably 250 nm or less, more preferably 200 nm or less, further preferably 150 nm or less, 130 nm or less, 110 nm or less, or 90 nm or less. Is particularly preferable. The lower limit of the Rq value is not particularly limited, but in order to stabilize the adhesion strength with the conductor layer, it is 10 nm or more, 30 nm or more.
The arithmetic mean roughness (Ra) and the root mean square roughness (Rq) of the surface of the insulating layer can be measured using a non-contact surface roughness meter. A specific example of the non-contact type surface roughness meter is "WYKO NT3300" manufactured by Beecoin Instruments.

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

[Semiconductor device]
A semiconductor device can be manufactured using the printed wiring board manufactured by the method of the present invention.

  Examples of such semiconductor devices include various semiconductor devices provided for electric products (for example, computers, mobile phones, digital cameras, televisions, etc.) and vehicles (for example, motorcycles, automobiles, trains, ships, aircrafts, etc.). ..

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

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

[Preparation of measurement / evaluation sample]
(1) Undercoating of inner layer circuit board A glass cloth base material epoxy resin double-sided copper clad laminate having an inner layer circuit (copper foil thickness 18 μm, substrate thickness 0.3 mm, “R5715ES” manufactured by Matsushita Electric Works, Ltd.) Both surfaces were etched by 1 μm with “CZ8100” manufactured by MEC Co., Ltd. to roughen the copper surface.

(2) Lamination of resin sheet with support A resin sheet with support prepared in Examples and Comparative Examples was prepared using a batch-type vacuum pressure laminator ("MVLP-500" manufactured by Meiki Seisakusho Co., Ltd.). The composition layer was laminated on both surfaces of the inner layer circuit board so that the composition layer was in contact with the inner layer circuit board. The lamination was performed by decompressing for 30 seconds to reduce the atmospheric pressure to 13 hPa or less, and then laminating at 100 ° C. and a pressure of 0.74 MPa for 30 seconds.

(3) Curing of resin composition The laminated resin sheet with a support was heated at 80 ° C for 30 minutes and then at 170 ° C for 30 minutes to thermally cure the resin composition layer to form an insulating layer.

(4) via holes formed by Hitachi Via Mechanics Co. CO ₂ laser processing machine using "LC-2E21B / 1C", and drilling the insulating layer from the support, to form a via hole. The top diameter (diameter) of the via hole on the surface of the insulating layer was 50 μm. The conditions for drilling are: mask diameter 1.60 mm, focus offset value 0.050, pulse width 25 μs, energy 0.33 mJ / shot (output 0.66 W, frequency 2000 Hz), aperture 13, shot number 2, burst mode. Met.

(5) Desmear Treatment After the via hole was formed, the inner layer circuit board on which the insulating layer was formed was desmear treated while the support was still attached. With respect to the substrate after the desmear treatment, the smear removability at the bottom of the via hole was evaluated. As the desmear treatment, the following wet desmear treatment or dry desmear treatment was performed.
Wet desmear treatment:
The inner layer circuit board on which the insulating layer is formed is immersed in a swelling solution (“Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd., an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 5 minutes, and then an oxidant solution ( Atotech Japan Co., Ltd. “Concentrate Compact P”, an aqueous solution of potassium permanganate concentration of about 6% and sodium hydroxide concentration of about 4% for 20 minutes at 80 ° C., and finally a neutralization liquid (Atotech Japan “Reduction Shoryushin Securigant P” (manufactured by K.K.), sulfuric acid aqueous solution) at 40 ° C. for 5 minutes, and then dried at 80 ° C. for 15 minutes.
Dry desmear treatment:
The inner layer circuit board on which the insulating layer was formed was subjected to a condition of O ₂ / CF ₄ (mixed gas ratio) = 25/75 and a vacuum degree of 100 Pa by using a vacuum plasma etching device (100-E PLASMA SYSTEM manufactured by Tepla). For 5 minutes.

(6) Peeling of Support The support was peeled off to expose the surface of the insulating layer.

(7) Formation of Conductor Layer A conductor layer was formed on the exposed surface of the insulating layer. The conductor layer was formed by the following wet method or dry method. The following wet method corresponds to the step (F-1) described above, and the following dry method corresponds to the step (F-2).
Wet method:
The inner layer circuit board on which the insulating layer is formed is immersed in a swelling solution (“Swelling Dip Securigant P” manufactured by Atotech Japan Co., an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60 ° C. for 10 minutes, and then a roughening solution ( Atotech Japan Co., Ltd. “Concentrate Compact P”, an aqueous solution of potassium permanganate concentration of about 6% and sodium hydroxide concentration of about 4% for 20 minutes at 80 ° C., and finally a neutralization liquid (Atotech Japan "Reduction Shoryushin Securigant P" (manufactured by K.K.), aqueous solution of sulfuric acid) at 40 ° C. for 5 minutes, and then dried at 80 ° C. for 30 minutes. The substrate after drying is referred to as “evaluation substrate A”.
After that, the evaluation substrate A was immersed in a solution for electroless plating containing PdCl ₂ at 40 ° C. for 5 minutes and then in an electroless copper plating solution at 25 ° C. for 20 minutes. After heating at 150 ° C. for 30 minutes to perform an annealing treatment, an etching resist is formed according to the semi-additive method, a pattern is formed by exposure and development, and copper sulfate electrolytic plating is performed to form a conductor layer with a thickness of 25 μm. Formed. After forming the conductor pattern, it was annealed by heating at 190 ° C. for 60 minutes. The obtained printed wiring board is referred to as "evaluation board B".
Dry method:
In the dry method, the substrate from which the support is peeled off to expose the surface of the insulating layer is referred to as “evaluation substrate A”. A titanium layer (thickness: 30 nm) and then a copper layer (thickness: 300 nm) were formed on the evaluation substrate A by using a sputtering device (“E-400S” manufactured by Canon ANELVA CORPORATION). The obtained substrate is heated at 150 ° C. for 30 minutes to be annealed, and then an etching resist is formed according to the semi-additive method. After patterning by exposure / development, copper sulfate electrolytic plating is performed to form a 25 μm film. To form a conductor layer. After forming the conductor pattern, it was annealed by heating at 190 ° C. for 60 minutes. The obtained printed wiring board is referred to as "evaluation board B".

<Measurement and evaluation of arithmetic mean roughness (Ra value) and root mean square roughness (Rq value)>
For the evaluation board A, using a non-contact type surface roughness meter (“WYKO NT3300” manufactured by Bee Coin Instruments Co., Ltd.), the Ra value and the Rq value are obtained by the VSI contact mode and the numerical value obtained by the 50 × lens as the measurement range of 121 μm × 92 μm. I asked. The measurement was performed by obtaining an average value of 10 points randomly selected.

<Measurement of adhesion strength (peel strength) between insulating layer and conductor layer>
The measurement of the peel strength between the insulating layer and the conductor layer was performed on the evaluation board B in accordance with JIS C6481. Specifically, the conductor layer of the evaluation board B is cut into a portion having a width of 10 mm and a length of 100 mm, and one end is peeled off and gripped by a gripping tool, and at room temperature, it is vertically moved at a speed of 50 mm / min. The load (kgf / cm) when peeling off 35 mm was measured to determine the peel strength. A tensile tester (“AC-50C-SL” manufactured by TSE Co., Ltd.) was used for the measurement.

<Evaluation of smear removability>
The periphery of the bottom of the via hole was observed with a scanning electron microscope (SEM), and the maximum smear length from the wall surface of the bottom of the via hole was measured from the obtained image. The smear removability was evaluated according to the following criteria.
Evaluation criteria:
◯: Maximum smear length is less than 3 μm ×: Maximum smear length is 3 μm or more

[Production Example 1]
(1) Preparation of Resin Varnish 1 5 parts of bisphenol type epoxy resin (epoxy equivalent of about 165, "ZX1059" manufactured by Nippon Steel Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), bixylenol type Epoxy resin (epoxy equivalent of about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation) 10 parts, biphenyl type epoxy resin (epoxy equivalent of about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.) 10 parts, and phenoxy resin (Mitsubishi 10 parts of “YL7553BH30” manufactured by Kagaku Co., Ltd., a methyl ethyl ketone (MEK) solution having a solid content of 30 mass% was dissolved in 20 parts of solvent naphtha while stirring. After cooling to room temperature, 18 parts of a naphthol-based curing agent (hydroxyl group equivalent 215, "SN-485" manufactured by Nippon Steel Chemical Co., Ltd., MEK solution with a solid content of 60%), a triazine-containing phenol novolac-based curing agent Agent (hydroxyl group equivalent 146, "LA-1356" manufactured by DIC Corporation, MEK solution with 60% solid content) 6 parts, curing accelerator (4-dimethylaminopyridine (DMAP), MEK solution with 2% solid content) 4 parts, flame retardant (“HCA-HQ” manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size) Spherical silica (average particle size 0.5 μm, “SOC2” manufactured by Admatechs Co., Ltd., unit area), surface-treated with an aminosilane coupling agent (“KBM573” manufactured by Shin-Etsu Chemical Co., Ltd.) Per car 120 parts of a Bonn amount of 0.39 mg / m ² ) were mixed and uniformly dispersed with a high-speed rotary mixer to prepare a resin varnish 1.
(2) Preparation of Resin Sheet 1 with Support As a support, a PET film (“AL5” manufactured by Lintec Co., Ltd., thickness 38 μm) release-treated with an alkyd resin release agent was prepared. The resin varnish 1 was applied to the release surface of the support with a die coater and dried at 180 ° C. to 120 ° C. (average 100 ° C.) for 5 minutes to form a resin composition layer 1. The resin composition layer 1 had a thickness of 30 μm. Next, a smooth surface side of a polypropylene film (“Alphan MA-411” manufactured by Oji Special Paper Co., Ltd., thickness 15 μm) as a protective film is attached to the surface of the resin composition layer 1 not bonded to the support. Thus, a resin sheet with a support 1 having a layer structure of protective film / resin composition layer 1 / support was obtained.

[Production Example 2]
(1) Preparation of resin varnish 2 5 parts of bisphenol type epoxy resin (epoxy equivalent of about 165, "ZX1059" manufactured by Nippon Steel Chemical Co., Ltd., 1: 1 mixture of bisphenol A type and bisphenol F type), bixylenol type Epoxy resin (epoxy equivalent of about 185, "YX4000HK" manufactured by Mitsubishi Chemical Corporation) 10 parts, biphenyl type epoxy resin (epoxy equivalent of about 290, "NC3000H" manufactured by Nippon Kayaku Co., Ltd.) 10 parts, and phenoxy resin (Mitsubishi 10 parts of "YL7553BH30" manufactured by Kagaku Co., Ltd., a MEK solution having a solid content of 30% by mass) was dissolved in 30 parts of solvent naphtha with heating while stirring. After cooling to room temperature, 20 parts of an active ester compound (active group equivalent of about 223, "HPC8000-65T" manufactured by DIC Corporation, a toluene solution of 65% by mass of non-volatile components), a naphthol-based curing agent (hydroxyl group equivalent) 215, Nippon Steel Chemical Co., Ltd. "SN-485", solid content 60% MEK solution) 12 parts, curing accelerator (4-dimethylaminopyridine (DMAP), solid content 2% by mass MEK solution) 4 Part, flame retardant ("HCA-HQ" manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10-phosphaphenanthrene-10-oxide, average particle size 2 μm) 2 parts, spherical silica (average particle size 0.5 μm, manufactured by Admatechs Co., Ltd. “SOC2”, unit area, surface-treated with an aminosilane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM573”) Per car 150 parts of a Bonn amount of 0.39 mg / m ² ) were mixed and uniformly dispersed with a high-speed rotary mixer to prepare a resin varnish 2.
(2) Manufacture of resin sheet 2 with a support Using the resin varnish 2 prepared in (1) above, a layer structure of protective film / resin composition layer 2 / support is obtained in the same manner as in Preparation Example 1. A resin sheet 2 with a support was obtained.

  Table 1 shows the compositions of the resin composition layers of the resin sheets 1 and 2 with a support.

<Example 1>
A printed wiring board was manufactured using the resin sheet with a support 1 according to the procedure of [Preparation of measurement / evaluation sample].
In Example 1, the dry desmear treatment was performed as the desmear treatment, and the conductor layer was formed by the dry method. The evaluation results are shown in Table 2.

<Example 2>
A printed wiring board was manufactured using the resin sheet with a support 2 according to the procedure of [Preparation of measurement / evaluation sample].
In Example 2, a wet desmear treatment was performed as the desmear treatment, and the conductor layer was formed by the wet method. The evaluation results are shown in Table 2.

<Example 3>
A printed wiring board was manufactured using the resin sheet with a support 2 according to the procedure of [Preparation of measurement / evaluation sample].
In Example 3, the dry desmear treatment was performed as the desmear treatment, and the conductor layer was formed by the wet method. The evaluation results are shown in Table 2.

<Comparative Example 1>
A printed wiring board was produced in the same manner as in Example 1 except that the order of (5) desmear treatment and (6) peeling of the support was replaced in the procedure of [Preparation of measurement / evaluation sample]. The evaluation results are shown in Table 2.
In Comparative Example 1, the substrate after the dry desmear treatment was used as the “evaluation substrate A”.

<Comparative example 2>
A printed wiring board was produced in the same manner as in Example 2 except that (5) Desmear treatment was omitted in the procedure of [Preparation of measurement / evaluation sample]. The evaluation results are shown in Table 2.

<Comparative example 3>
A printed wiring board was produced in the same manner as in Example 2 except that the order of (5) desmear treatment and (6) peeling of the support was replaced in the procedure of [Preparation of measurement / evaluation sample]. The evaluation results are shown in Table 2.

  In Examples 1 to 3 in which the desmear treatment is performed in a state where the support is attached to the insulating layer, it is possible to form an insulating layer having a low roughness and a high adhesion strength (peel strength) with the conductor layer, which is excellent. It was confirmed that smear removability was also exhibited. On the other hand, in Comparative Examples 1 and 3, the adhesion strength (peeling strength) between the insulating layer and the conductor layer was low although the roughness of the insulating layer surface was high. Moreover, in Comparative Example 2, the smear at the bottom of the via hole could not be sufficiently removed.

Claims (11)

(A) a step of laminating a resin sheet with a support including a support and a resin composition layer to be bonded to the support on an inner circuit board so that the resin composition layer is bonded to the inner circuit board;
(B) a step of thermosetting the resin composition layer of the resin sheet with a support to form an insulating layer,
(C) A step of forming a via hole by forming a hole in the insulating layer,
(D) Desmearing process,
(E) a step of peeling the support, and (F) a step of forming a conductor layer having a peel strength of 0.4 kgf / cm or more with the insulating layer on the surface of the insulating layer are included in this order,
In the step (B), the resin composition layer is preheated at a temperature of 50 ° C or higher and lower than 120 ° C for 5 minutes to 150 minutes, and then heated at a temperature of 120 ° C to 240 ° C for 5 minutes to 90 minutes. A method for manufacturing a printed wiring board, comprising:   The method for manufacturing a printed wiring board according to claim 1, wherein the desmear treatment in the step (D) is wet desmear treatment, dry desmear treatment, or a combination thereof. Process (F)
The method for manufacturing a printed wiring board according to claim 1 or 2, which comprises roughening the surface of the insulating layer and wet-plating the surface of the insulating layer to form a conductor layer in this order. Process (F)
The printed wiring board according to claim 1 or 2, which includes, in this order, dry-plating the surface of the insulating layer to form a metal layer, and wet-plating the surface of the metal layer to form a conductor layer. Production method.   The method for producing a printed wiring board according to any one of claims 1 to 4, wherein the resin composition layer of the resin sheet with a support contains an epoxy resin, a curing agent and an inorganic filler.   The method for manufacturing a printed wiring board according to claim 5, wherein the curing agent contains an active ester curing agent.   The method for manufacturing a printed wiring board according to claim 5, wherein the inorganic filler has an average particle diameter of 0.01 μm to 3 μm.   Content of the inorganic filler in a resin composition layer is 40 mass% -95 mass% when the non-volatile component of a resin composition layer is 100 mass%, Any one of Claims 5-7. A method for manufacturing the printed wiring board described.   The method for producing a printed wiring board according to claim 5, wherein the inorganic filler is surface-treated with a surface treatment agent.   The print according to any one of claims 5 to 9, wherein the content of the inorganic filler in the resin composition layer is 72% by mass or more when the nonvolatile component of the resin composition layer is 100% by mass. Wiring board manufacturing method.   A method for manufacturing a semiconductor device using the printed wiring board manufactured by the method according to claim 1.