JP2017112284A - Insulating resin film, insulating resin film with support, and multilayer printed wiring board - Google Patents

Abstract

[Problem] To provide an insulating resin film that can improve the removability of via posts, and a multilayer printed wiring board formed using said insulating resin film. [Solution] The insulating resin film is formed using a thermosetting resin composition containing (a) epoxy resin, (b) phenolic resin, (c) inorganic filler, and (d) a phosphorus-based curing accelerator, and is an insulating resin film for multilayer printed wiring boards obtained through a via formation process by removing a photosensitive resin layer. [Selected Figure] None

Description

  The present invention relates to an insulating resin film, an insulating resin film with a support, and a multilayer printed wiring board.

A printed wiring board, which is one of the structures having conductor circuits, is a structure in which a plurality of wiring layers are formed on a core substrate, and a copper-clad laminate serving as a core substrate and interlayer insulation provided between each wiring layer And a solder resist provided on the outermost surface. On the printed wiring board, a semiconductor element is usually mounted via a die bonding material or an underfill material. If necessary, the entire surface may be sealed with a transfer sealing material, and a metal cap (lid) for improving heat dissipation may be attached.
In recent years, semiconductor devices have become lighter and shorter, and the density of semiconductor elements and multilayer printed wiring boards has been increasing. Further, packaging forms such as a package-on-package in which a semiconductor device is stacked on a semiconductor device are actively performed, and it is expected that the mounting density of the semiconductor device will be further increased in the future.

  Here, the manufacturing method of the conventional multilayer printed wiring board is shown in FIG. A multilayer printed wiring board 100 shown in FIG. 1F has a wiring pattern on the surface and inside. The multilayer printed wiring board 100 is obtained by laminating a copper clad laminate, an interlayer insulating material, a metal foil, and the like and appropriately forming a wiring pattern by an etching method or a semi-additive method.

  First, an interlayer insulating layer 103 is formed on both surfaces of a copper clad laminate 101 having a wiring pattern 102 on the surface (see FIG. 1A). The interlayer insulating layer 103 may be printed with a thermosetting resin composition using a screen printer or a roll coater, or a film made of the thermosetting resin composition is prepared in advance, and this film is used with a laminator. Can also be attached to the surface of the printed wiring board. Next, an opening 104 is formed using a YAG laser or a carbon dioxide gas laser in a place that needs to be electrically connected to the outside, and smear (residue) around the opening 104 is removed by a desmear process (FIG. 1B). reference). Next, a seed layer (thin conductive layer) 105 is formed by an electroless plating method (see FIG. 1C). A photosensitive resin composition is laminated on the seed layer 105, and a predetermined portion is exposed and developed to form a photosensitive resin layer pattern 106 (see FIG. 1D). Next, the wiring pattern 107 is formed by an electrolytic plating method, and the cured product of the photosensitive resin composition is removed by a peeling solution, and then the seed layer 105 is removed by etching (see FIG. 1E). The multilayer printed wiring board 100 can be manufactured by repeating the above and forming the solder resist 108 on the outermost surface (see FIG. 1F). In the multilayer printed wiring board 100 obtained in this way, semiconductor elements are mounted at corresponding locations, and electrical connection can be ensured.

By the way, it is necessary to provide vias (openings) for electrically connecting the upper and lower wiring layers in the interlayer insulating layer of the multilayer printed wiring board. If the number of flip chip pins mounted on the multilayer printed wiring board increases, it is necessary to provide openings corresponding to the number of pins. The conventional multilayer printed wiring board has a low mounting density, and the number of pins of the semiconductor element to be mounted is designed from several thousand pins to around 10,000 pins, so it is necessary to make the openings small in diameter and narrow pitch There was no. However, as the miniaturization of semiconductor elements progresses and the number of pins increases from tens of thousands to hundreds of thousands of pins, the openings formed in the interlayer insulating layer of the multilayer printed wiring board are also narrowed according to the number of pins of the semiconductor elements. There is a growing need for
Hitherto, development of multilayer printed wiring boards in which openings are provided by laser in an interlayer insulating layer using a thermosetting resin composition has been advanced (see, for example, Patent Documents 1 to 4). However, the multilayer printed wiring board 100 manufactured by the method shown in FIG. 1 requires introduction of a new facility such as a laser, and it is difficult to provide a relatively large opening or a minute opening of 60 μm or less. There are problems that it is necessary to use different lasers according to the aperture diameter, and it is difficult to provide a special shape. In addition, when forming an opening using a laser, each opening must be formed one by one. Therefore, it is time-consuming when it is necessary to provide a large number of fine openings, and resin residues around the openings. Therefore, unless the residue is removed, there is a problem that the reliability of the obtained multilayer printed wiring board is lowered.
Therefore, in order to solve the above-described problem, a method using a photosensitive resin composition has been proposed as a method of providing an opening without using a laser. More specifically, after forming the photosensitive resin layer on the support, a step of patterning by performing exposure processing and development processing, and then a step of laminating the insulating resin layer so as to cover the formed pattern, Subsequently, a step of exposing a predetermined portion of the pattern from the thermosetting resin layer by removing a part of the insulating resin layer, and removing the exposed thermosetting resin layer to open the thermosetting resin layer There has been proposed a method including a step of providing (see, for example, Patent Document 5).

JP 08-279678 A JP-A-11-054913 JP 2001-217543 A Japanese Patent Laid-Open No. 2003-017848 International Publication No. 2013/054790

According to further studies by the present inventors, it has been found that, in the method described in Patent Document 5, the removability of the pattern (hereinafter also referred to as via post) may be lowered depending on the type of the insulating resin layer.
Therefore, an object of the present invention is to provide an insulating resin film capable of improving the removability of via posts, and a multilayer printed wiring board formed using the insulating resin film.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that (a) an epoxy resin, (b) a phenol resin, (c) an inorganic filler, and (d) a thermosetting agent containing a phosphorus-based curing accelerator. It has been found that an insulating resin film formed using a conductive resin composition can solve the above-mentioned problems, and has completed the present invention. The present invention has been completed based on such knowledge.

The present invention relates to the following [1] to [9].
[1] An insulating resin film formed using a thermosetting resin composition containing (a) an epoxy resin, (b) a phenol resin, (c) an inorganic filler, and (d) a phosphorus curing accelerator. An insulating resin film for a multilayer printed wiring board obtained through a via formation step by removing the photosensitive resin layer.
[2] (d) The phosphorus curing accelerator is an organic phosphine, a complex of organic phosphine and organic boron, an adduct of a tertiary phosphine and a quinone compound, a phosphonium salt, and a thiocyanate of a quaternary phosphine. The insulating resin film according to [1], which is at least one selected from the group consisting of:
[3] The insulating resin film according to the above [1] or [2], wherein the content of the inorganic filler (c) in the nonvolatile content of the thermosetting resin composition is 1 to 70% by mass.
[4] The insulating resin film according to any one of [1] to [3], wherein (c) the inorganic filler is silica.
[5] The insulating resin film according to any one of [1] to [4], wherein (c) the inorganic filler is silica that has been surface-treated.
[6] (a) The epoxy resin is a polyfunctional epoxy resin having an average of more than two epoxy groups in the molecule, or an epoxy resin represented by the following formula (1): The insulating resin film according to any one of [1] to [5].

(In the formula, p represents 1 to 5.)
[7] The photosensitive resin layer is a layer containing (1) a binder polymer, (2) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (3) a photopolymerization initiator, And (1) The insulating resin film in any one of said [1]-[6] whose binder polymer has a carboxyl group.
[8] An insulating resin film with a support, comprising a support on one side of the insulating resin film according to any one of [1] to [7].
[9] A multilayer printed wiring board formed using the insulating resin film according to any one of [1] to [8].

  According to the present invention, an insulating resin film capable of enhancing the removability of via posts, an insulating resin film with a support, and a multilayer printed wiring board formed using the insulating resin film are obtained.

It is a schematic diagram which shows the manufacturing method of the conventional multilayer printed wiring board. (A): It is sectional drawing which shows the inner-layer board | substrate before giving a conductor circuit formation. (B): It is sectional drawing which shows the inner-layer board | substrate which performed conductor circuit formation. It is sectional drawing which shows the photosensitive resin layer formation process (a). It is sectional drawing which shows a via post formation process (b). It is sectional drawing which shows an insulating resin layer formation process (c). It is sectional drawing which shows a cueing process (d). It is sectional drawing which shows an opening formation process (e). FIG. 6 is a cross-sectional view showing a seed layer 5 forming step. It is sectional drawing which shows a 2nd photosensitive resin layer pattern formation process. 7 is a cross-sectional view showing a process for forming a wiring part 7. FIG. It is sectional drawing which shows the wiring pattern 7a and 7b formation process. It is sectional drawing which shows the one aspect | mode of the multilayer printed wiring board of this invention. FIG. 3 is a photomicrograph showing via post removability in Example 1. 6 is a micrograph showing the removal property of via posts in Comparative Example 1. FIG.

Hereinafter, the present invention will be described in detail.
[Insulating resin film]
The insulating resin film of the present invention is formed using a thermosetting resin composition containing (a) an epoxy resin, (b) a phenol resin, (c) an inorganic filler, and (d) a phosphorus-based curing accelerator. It is an insulating resin film, and is an insulating resin film for a multilayer printed wiring board obtained through a via formation step by removing a photosensitive resin layer.
As described above, the insulating resin film of the present invention is particularly useful for a multilayer printed wiring board obtained through a via forming step by removing a photosensitive resin layer. The method for producing a multilayer printed wiring board through a via forming step by removing a photosensitive resin layer can refer to Patent Document 5, but in this method, by utilizing the insulating resin film of the present invention for the insulating resin layer, It is possible to effectively suppress degradation of via post removability. The reason why such an effect appears is not clear, but is presumed as follows.
The formation of the opening by removing the via post is usually performed using a resin residue removing solution after forming the via, a so-called desmear solution or the like. In the removal of via posts, in order to selectively remove via posts, it is necessary that there is a difference in solubility in the desmear liquid between the insulating resin layer and the via posts, and the via posts are selectively selected using the difference in solubility. Use a desmear solution that can be removed. However, if the solubility of the via post in the desmear liquid is lowered due to some influence, it is directly connected to a decrease in the removability of the via post. In fact, conventionally, the decrease in the removability of the via post has often been a problem. As one of the causes of a decrease in the solubility of the via post in the desmear solution, it is considered that chemical resistance is improved by a reaction between the carboxyl group in the via post and the epoxy group in the insulating resin layer. The present inventors speculate that the reaction between the carboxyl group and the epoxy group may be accelerated depending on the type of the curing accelerator, thereby improving the chemical resistance of the via post, and thereby reducing the via post removability. did. Since the carboxyl group present in the via post is a weakly acidic functional group, for example, when a curing accelerator having a basic site that can activate the carboxyl group, such as imidazole, is used, the reaction promoting effect of the carboxyl group and the epoxy group is enhanced. It is considered large. Therefore, if a phosphorus curing accelerator is used as a curing accelerator that does not activate the carboxyl group site, the reaction between the carboxyl group in the via post and the epoxy group in the insulating resin layer is not promoted, and the via post removability is improved. It was inferred that it would lead to the present invention.

Hereinafter, each component which a thermosetting resin composition contains is demonstrated in order.
((A) Epoxy resin)
(A) As the epoxy resin, an epoxy resin having two or more epoxy groups in one molecule is preferable from the viewpoint of insulation. Here, the epoxy resin is classified into a glycidyl ether type epoxy resin, a glycidyl amine type epoxy resin, a glycidyl ester type epoxy resin, and the like. Among these, a glycidyl ether type epoxy resin is preferable.
Examples of the resin having two epoxy groups in one molecule include bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol S type epoxy resin; and fats such as dicyclopentadiene type epoxy resin. Examples thereof include cyclic epoxy resins; aliphatic chain epoxy resins; biphenol type epoxy resins; naphthalene type epoxy resins.
Further, a polyfunctional epoxy resin having an average of more than two epoxy groups in the molecule may be used. Examples of the polyfunctional epoxy resin include novolak type epoxy resins such as phenol aralkyl novolak type epoxy resins, biphenyl aralkyl novolak type epoxy resins (hereinafter referred to as aralkyl novolak type epoxy resins), phenol novolak type epoxy resins, and cresol novolak type epoxy resins. Is mentioned. In particular, from the viewpoint of adhesive strength with a conductor layer and insulation reliability, an aralkyl novolak type epoxy resin is preferable, and a biphenyl aralkyl novolak type epoxy resin is more preferable. The biphenyl aralkyl novolak type epoxy resin refers to an aralkyl novolak type epoxy resin containing an aromatic ring of a biphenyl derivative in one molecule.
(A) As an epoxy resin, a polyfunctional epoxy resin is preferable.

As the epoxy resin, an epoxy resin represented by the following formula (1) is also preferable.

(In the formula, p represents 1 to 5.)
p is preferably 1.2 to 5, more preferably 1.4 to 3.

In addition, a polymer type epoxy resin such as a phenoxy resin can also be used.
(A) The epoxy equivalent of an epoxy resin becomes like this. Preferably it is 100-500 g / eq, More preferably, it is 150-400 g / eq, More preferably, it is 200-350 g / eq. Here, the epoxy equivalent is the mass of the resin per epoxy group (g / eq), and can be measured according to the method defined in JIS K 7236. Specifically, using an automatic titration apparatus “GT-200 type” (manufactured by Mitsubishi Chemical Analytech Co., Ltd.), 2 g of epoxy resin was weighed into a 200 ml beaker, 90 ml of methyl ethyl ketone was dropped, and after dissolving in an ultrasonic cleaner, It is determined by adding 10 ml of glacial acetic acid and 1.5 g of cetyltrimethylammonium bromide and titrating with a 0.1 mol / L perchloric acid / acetic acid solution.
(A) An epoxy resin may be used individually by 1 type, and may use 2 or more types together.
Commercially available products of the biphenylaralkyl novolak type epoxy resin include “NC-3000” (epoxy resin having p = 1.7 in the above formula (1), epoxy equivalent = 275 g / eq), “NC-3000H” (the above formula ( In 1), p = 2.8 epoxy resin, epoxy equivalent = 290 g / eq) [Nippon Kayaku Co., Ltd.].

((B) phenol resin)
(B) The phenol resin can function as a curing agent for the (a) epoxy resin.
(B) The phenol resin is not particularly limited as long as it is a phenol resin having two or more phenolic hydroxyl groups in one molecule. For example, compounds having two phenolic hydroxyl groups in one molecule such as resorcin, catechol, bisphenol A, bisphenol F and substituted or unsubstituted biphenol; aralkyl type phenol resin; dicyclopentadiene type phenol resin; triphenylmethane type Phenolic resins; phenolic novolac resins, cresol novolac resins, aminotriazine-modified novolac type phenolic resins and other novolac type phenolic resins; resol type phenolic resins; benzaldehyde type phenol and aralkyl type phenolic resins; p-xylylene and / or Or m-xylylene-modified phenol resin; melamine-modified phenol resin; terpene-modified phenol resin; dicyclopentadiene-type naphthol resin; cyclopentadiene-modified phenol resin Nord resin; polycyclic aromatic ring-modified phenolic resins; and biphenyl type phenolic resins. (B) A phenol resin may be used individually by 1 type, and may use 2 or more types together. Among these, from the viewpoint of insulation reliability, a novolak type phenol resin is preferable, a phenol novolak type phenol resin and an aminotriazine modified novolak type phenol resin are more preferable, and a phenol novolak type phenol resin and an aminotriazine modified novolak type phenol resin are used in combination. More preferably. The aminotriazine-modified novolak phenol resin is more preferably an aminotriazine-modified cresol novolac phenol resin.
(B) The hydroxyl equivalent of the phenol resin is preferably 90 to 200 g / eq, more preferably 95 to 250 g / eq, still more preferably 95 to 200 g / eq, and particularly preferably 100 to 160 g / eq.
(B) Examples of commercially available phenolic resins include “Phenolite (registered trademark) TD-2131”, “Phenolite (registered trademark) TD-2106” (above, phenol novolac type phenolic resin, manufactured by DIC Corporation), “ “Phenolite (registered trademark) LA-3018”, “Phenolite (registered trademark) LA-1356”, “Phenolite (registered trademark) LA7050” series, “Phenolite (registered trademark) LA-3018-50P” (above, Aminotriazine-modified novolac phenol resin, manufactured by DIC Corporation), and the like.

((C) inorganic filler)
(C) As an inorganic filler, for example, silica, alumina, barium sulfate, talc, mica, kaolin, boehmite, barium titanate, potassium titanate, strontium titanate, calcium titanate, bismuth titanate, aluminum carbonate, water Magnesium oxide, aluminum hydroxide, aluminum borate, aluminum silicate, calcium carbonate, magnesium carbonate, magnesium oxide, calcium silicate, magnesium silicate, zinc borate, zinc stannate, zinc oxide, titanium oxide, beryllium oxide, carbonized Examples thereof include clays such as silicon, silicon nitride, boron nitride, and fired clay, short glass fibers, glass powder, and hollow glass beads. Preferred examples of the glass include E glass, T glass, and D glass. (C) An inorganic filler may be used individually by 1 type, and may use 2 or more types together.
Among these, silica is preferable from the viewpoint of reducing the thermal expansion coefficient of the insulating resin layer.
Examples of the silica include precipitated silica produced by a wet method and having a high water content, and dry method silica produced by a dry method and containing almost no bound water or the like. Examples of the dry process silica include crushed silica, fumed silica, and fused silica (fused spherical silica) depending on the production method. The silica used for the inorganic filler is preferably fused silica from the viewpoint of low thermal expansion and high fluidity when filled in the resin. The shape of the silica is preferably spherical in order to facilitate embedding the through holes formed in the inner layer circuit and the unevenness of the circuit pattern.
Examples of commercially available products of spherical silica include “SO-C1” (average particle size: 0.25 μm), “SO-C2” (average particle size: 0.5 μm), and “SO-C3” (average particle size). : 0.9 μm), “SO-C5” (average particle size: 1.6 μm), “SO-C6” (average particle size: 2.2 μm) [above, manufactured by Admatechs Co., Ltd.], “UFP-40” (Average particle diameter: 0.3 μm) [manufactured by Denki Kagaku Kogyo Co., Ltd.] and the like.

Silica is preferably surface-treated silica, more preferably silica surface-treated with a silane coupling agent. When silica surface-treated with a silane coupling agent is used, the adhesive force between the silica and the resin component is improved, the silica is prevented from falling off, and the surface roughness tends to be lowered.
Examples of the silane coupling agent include amino silane coupling agents, epoxy silane coupling agents, phenyl silane coupling agents, alkyl silane coupling agents, and alkenyl silane coupling agents (for example, vinyl silane coupling agents). Etc.), alkynylsilane coupling agents, haloalkylsilane coupling agents, siloxane coupling agents, hydrosilane coupling agents, silazane coupling agents, alkoxysilane coupling agents, chlorosilane coupling agents, (meta ) Acrylic silane coupling agent, amino silane coupling agent, isocyanurate silane coupling agent, ureido silane coupling agent, mercapto silane coupling agent, sulfide silane coupling And the like such as an isocyanate silane coupling agent. Among these, an aminosilane coupling agent is preferable from the viewpoint of the low surface roughness of the insulating resin layer and the peel strength from the metal foil.

(C) It is preferable that the average particle diameter of an inorganic filler is 0.01-3 micrometers, It is more preferable that it is 0.01-1 micrometer, It is further more preferable that it is 0.1-1 micrometer. In particular, when silica is used as the inorganic filler, the average particle diameter of silica is preferably in the above range.
(C) By making the average particle diameter of an inorganic filler into the said range, it exists in the tendency for the surface roughness of an insulating resin layer to reduce, maintaining film moldability favorable.
The average particle diameter is the particle diameter at a point corresponding to a volume of 50% when the cumulative frequency distribution curve based on the particle diameter is obtained with the total particle volume as 100%, and the laser diffraction scattering method is used. It can be measured with a particle size distribution measuring device.

((D) phosphorus curing accelerator)
(D) There is no restriction | limiting in particular as a phosphorus hardening accelerator, unless it has a site | part which activates a carboxyl group and accelerate | stimulates a reaction with an epoxy group, The well-known used as a hardening accelerator of an epoxy resin The following phosphorus-based curing accelerator can be used. (D) A phosphorus hardening accelerator may be used individually by 1 type, and may use 2 or more types together.
(D) Examples of phosphorus curing accelerators include triphenylphosphine, diphenyl (alkylphenyl) phosphine, tris (alkylphenyl) phosphine, tris (alkoxyphenyl) phosphine, tris (alkylalkoxyphenyl) phosphine, and tris (dialkylphenyl). ) Phosphine, tris (trialkylphenyl) phosphine, tris (tetraalkylphenyl) phosphine, tris (dialkoxyphenyl) phosphine, tris (trialkoxyphenyl) phosphine, tris (tetraalkoxyphenyl) phosphine, etc., triarylphosphine, trialkyl Organic phosphines such as phosphine, dialkylarylphosphine, alkyldiarylphosphine; phosphonium borate compounds, tetraphenylphospho Complexes of organic phosphines and organic boron, such as um tetraphenylborate and n-butylphosphonium tetraphenylborate; adducts of tertiary phosphines and quinone compounds (such as 1,4-benzoquinone); tetrabutylphosphonium decane Examples include phosphonium salts such as acid salts; thiocyanate compounds of quaternary phosphines such as (4-methylphenyl) triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate.
(D) Examples of the phosphorus curing accelerator include JP-A-2006-233190, JP-A-2009-298960, JP-A-2011-179008, JP-A-2014-025042, JP-A-2015-000940. And the like, and phosphorus-based curing accelerators and similar compounds described therein.
Among these, (d) phosphorus curing accelerators include organic phosphines, complexes of organic phosphines and organic boron, adducts of tertiary phosphines and quinone compounds, phosphonium salts, and quaternary phosphine thiocyanates. At least one selected from the group consisting of a compound is preferable, an adduct of a tertiary phosphine and a quinone compound is more preferable, an adduct of a triarylphosphine and a quinone compound is more preferable, and a triarylphosphine and 1 Adducts with 1,4-benzoquinone are particularly preferred.
(D) Examples of commercially available phosphorus curing accelerators include “P2” (1,4-benzoquinone adduct of triphenylphosphine, manufactured by Hokuko Chemical Co., Ltd.), “TBP2” (tri-n-butylphosphine). 1,4-benzoquinone adduct, manufactured by Hokuko Chemical Co., Ltd.) and the like.

(Other ingredients)
Each of the thermosetting resin composition (1) and the thermosetting resin composition (2) may further contain other components.
Other components include, for example, organic fillers, thickeners, flame retardants, thermoplastic resins, ultraviolet absorbers, antioxidants, photopolymerization initiators, fluorescent brighteners, colorants, adhesion improvers, and leveling. Agents and the like.
Examples of the organic filler include resin particles made of polyethylene, polypropylene, polystyrene, polyphenylene ether resin, silicone resin, tetrafluoroethylene resin, etc .; made of acrylate ester resin, methacrylate ester resin, conjugated diene resin, etc. Resin particles having a so-called core-shell structure having a rubbery core layer and a glassy shell layer made of an acrylic ester resin, a methacrylic ester resin, an aromatic vinyl resin, a vinyl cyanide resin, or the like Can be mentioned.
Examples of the thickener include olben, benton and the like.
Examples of the flame retardant include halogen flame retardants containing bromine and / or chlorine; phosphorus flame retardants such as triphenyl phosphate, tricresyl phosphate, trisdichloropropyl phosphate, phosphate ester compounds, red phosphorus; sulfamine Nitrogen flame retardants such as acid guanidine, melamine sulfate, melamine polyphosphate, melamine cyanurate; phosphazene flame retardants such as cyclophosphazene and polyphosphazene. As the flame retardant, a non-halogen flame retardant is preferable from the viewpoint of environmental protection. Flame retardants include those that are simply filled, that is, those that do not react with the insulating resin composition, and those that have a functional group that reacts with the insulating resin composition. As the former commercial product, for example, “PX-200” (manufactured by Eighth Chemical Industry Co., Ltd.) which is an aromatic phosphate ester flame retardant, “Exolit OP 930” (Clariant Japan Co., Ltd.) which is a polyphosphate compound. Etc.). Commercially available flame retardants having a functional group that reacts with the insulating resin composition include, for example, “FX-305” (manufactured by Tohto Kasei Co., Ltd.), which is an epoxy phosphorus-containing flame retardant, and a phenol phosphorus-containing flame retardant. “HCA-HQ” (manufactured by Sanko Co., Ltd.) and “XZ92741” (manufactured by Dow Chemical Co., Ltd.).
Examples of the thermoplastic resin include polyphenylene ether resin, phenoxy resin, polycarbonate resin, polyester resin, polyamide resin, polyimide resin, polyamideimide resin, xylene resin, petroleum resin, and silicone resin.
Examples of the ultraviolet absorber include a thiazole ultraviolet absorber and a triazole ultraviolet absorber. Examples of the antioxidant include hindered phenol-based antioxidants and hindered amine-based antioxidants. Examples of the photopolymerization initiator include benzophenones, benzyl ketals, and thioxanthone photopolymerization initiators. Examples of the fluorescent whitening agent include a fluorescent whitening agent of a stilbene derivative. Examples of the colorant include phthaloanine / blue, phthaloanine / green, iodin / green, disazo yellow, and carbon black. Examples of the adhesion improver include urea compounds such as urea silane; coupling agents such as silane coupling agents, titanate coupling agents, and aluminate coupling agents. Examples of the leveling agent include siloxane.

[Content Ratio of Components (a) to (d) in Thermosetting Resin Composition]
In the thermosetting resin composition, from the viewpoint of insulation reliability, the content of (a) the epoxy resin is preferably 20 to 90% by mass, more preferably 30 to 80% in the nonvolatile content of the thermosetting resin composition. It is 40 mass%, More preferably, it is 40-70 mass%.
In the thermosetting resin composition, from the viewpoint of insulation reliability, the content of the (b) phenol resin is preferably 10 to 80% by mass, more preferably 10 to 70%, in the nonvolatile content of the thermosetting resin composition. It is 20 mass%, More preferably, it is 20-40 mass%.
In the thermosetting resin composition, the content of the inorganic filler (c) is preferably 1 to 70% by mass, more preferably 10 to 50% by mass, and still more preferably in the nonvolatile content of the thermosetting resin composition. It is 20-40 mass%, Most preferably, it is 30-40 mass%. (C) When the content of the inorganic filler is within this range, low surface roughness is obtained while having a low thermal expansion coefficient, and an insulating resin film that exhibits high adhesive strength with the conductor layer tends to be obtained. .
In the thermosetting resin composition, the content of the (d) phosphorus-based curing accelerator is preferably 0.01 to 3% by mass, more preferably 0.01 to 2 in the nonvolatile content of the thermosetting resin composition. It is 0.01 mass%, More preferably, it is 0.01-1 mass%. If the content of the (d) phosphorus curing accelerator is 0.01% by mass or more in the nonvolatile content of the thermosetting resin composition, a sufficient curing accelerating action tends to be exhibited. Moreover, if the content of (d) the phosphorus-based curing accelerator is 3% by mass or less in the nonvolatile content of the thermosetting resin composition, the chemical resistance of the insulating resin layer is improved and the surface is roughened. It is suppressed and the adhesive strength with the conductor layer tends to decrease.

(Organic solvent)
The thermosetting resin composition may contain an organic solvent from the viewpoint of facilitating handling by dilution and facilitating formation of an insulating resin film. A thermosetting resin composition containing an organic solvent may be referred to as a resin varnish. In addition, this organic solvent may be used in a state where it is mixed with the respective components, or may be used arbitrarily separately from the respective components.
The organic solvent is not particularly limited, and examples thereof include alcohol solvents such as cellosolve, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether; carbitol solvents such as methyl carbitol and butyl carbitol; acetone, methyl ethyl ketone, and methyl isobutyl. Ketone solvents such as ketone and cyclohexanone; ester solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate and carbitol acetate; aromatic solvents such as toluene, xylene and mesitylene; dimethylformamide and dimethylacetamide And nitrogen atom-containing solvents such as N-methylpyrrolidone; sulfur atom-containing solvents such as dimethyl sulfoxide.
Among these, from the viewpoint of solubility and appearance after coating, an alcohol solvent, a ketone solvent, or a mixed solvent thereof is preferable, and propylene glycol monomethyl ether, methyl ethyl ketone, or a mixed solvent thereof is more preferable.
An organic solvent may be used individually by 1 type, and may use 2 or more types together.
The content of the organic solvent in the thermosetting resin composition is any non-volatile concentration (concentration of components other than the organic solvent) from the viewpoint of stabilizing the film thickness when forming the insulating resin film and improving the appearance. The amount is preferably 10 to 80% by mass, more preferably 20 to 75% by mass, still more preferably 40 to 75% by mass, and particularly preferably 50 to 70% by mass.

[Insulating resin film thickness]
The thickness of the insulating resin film of the present invention is not particularly limited, but is preferably 10 to 100 μm, more preferably 10 to 70 μm, still more preferably 10 to 50 μm, particularly preferably 15 to 40 μm, and most preferably 15-35 μm.
Here, the film thickness indicates the film thickness of an insulating resin film obtained by drying (the drying conditions will be described later).

[Insulating resin film with support]
The insulating resin film with a support of the present invention has a support on one side of the insulating resin film of the present invention. The support is usually finally peeled or removed when a multilayer printed wiring board is produced.
When the support is formed of a plurality of layers, a layer (two or more layers) left on the multilayer printed wiring board side together with the insulating resin film of the present invention and a layer to be peeled or removed (two or more layers) But it doesn't matter)
Examples of the support include polyethylene films, polyolefin films such as polyvinyl chloride, polyethylene terephthalate (hereinafter sometimes referred to as “PET”) films, polyethylene resin films such as polyethylene naphthalate films, polycarbonate films, and polyimide films. Release paper; metal foil such as copper foil and aluminum foil. An organic film with a release layer and a metal foil with a release layer can also be used.
When a copper foil is used for the support, the copper foil can be used as it is as a conductor layer to form a circuit. In this case, examples of the copper foil include rolled copper and electrolytic copper foil, and those having a thickness of 2 to 36 μm are generally used. When using a thin copper foil, a copper foil with a carrier may be used in order to improve workability. When using an organic resin film that does not use copper foil, a polyolefin film and a PET film are preferable, and a PET film is more preferable from the viewpoints of price and ease of handling. Examples of commercially available supports include PET films with a release layer such as “Unipeel (registered trademark) TR-1” (manufactured by Unitika Ltd.) and “Celapeel (registered trademark)” (manufactured by Toray Film Processing Co., Ltd.). Etc.
The support may be subjected to a surface treatment such as a mold release treatment, a plasma treatment, or a corona treatment. Examples of the release treatment include treatment with a silicon release agent, treatment with an olefin release agent, and the like.

  In addition, a protective film can be laminated | stacked on the insulating resin film of this invention. The protective film is mainly used for the purpose of preventing foreign matter from adhering to the insulating resin film of the present invention and scratching. The protective film is peeled off before laminating or hot pressing. The protective film may be the same material as the support. Although the thickness of a protective film is not specifically limited, Usually, it is preferably 1-40 μm.

[Method for producing insulating resin film]
Although there is no restriction | limiting in particular in the manufacturing method of the insulating resin film of this invention, After apply | coating a thermosetting resin composition on a support body, it can manufacture by the method which passes through a drying process.

As a condition for the drying step, in any case, a condition of drying at a temperature of 60 to 180 ° C. for 30 to 600 seconds is preferable. The temperature is more preferably 70 to 140 ° C. Drying may be a method of simply heating or a method of blowing hot air.
There is no restriction | limiting in particular in the application | coating method of a thermosetting resin composition, A well-known method can be utilized. For example, it can apply | coat using application apparatuses, such as a reverse coater, a gravure coater, an air doctor coater, a die coater, and a lip coater.

[Multilayer printed wiring board and manufacturing method thereof]
The present invention also provides a multilayer printed wiring board formed using the insulating resin film.
Although there is no restriction | limiting in particular in the manufacturing method of the multilayer printed wiring board of this invention, For example, it can manufacture with the manufacturing method which has the following process (a)-(f).
Step (a): A step of laminating a photosensitive resin composition on an inner layer substrate on which a conductor circuit has been formed to form a photosensitive resin composition layer (hereinafter also referred to as a photosensitive resin layer forming step (a)).
Step (b): A step of patterning by subjecting the photosensitive resin layer to exposure processing and development processing (hereinafter also referred to as photosensitive resin layer pattern (via post) formation step (b)).
Step (c): A step of laminating the insulating resin film of the present invention on the inner layer substrate so as to cover the post and forming an insulating resin layer (hereinafter also referred to as an insulating resin layer forming step (c)).
Step (d): A step of removing a part of the insulating resin layer to expose the via post (hereinafter also referred to as a cueing step (d)).
Step (e): A step of removing the via post and exposing a conductor circuit of the inner layer substrate (hereinafter also referred to as an opening forming step (e)).
Step (f): A step of forming a conductor circuit in the insulating resin layer and the opening (hereinafter also referred to as a conductor circuit formation step (f)).

(Photosensitive resin layer forming step (a))
In the photosensitive resin layer forming step (a), the method for forming the photosensitive resin composition layer on the inner layer substrate on which the conductor circuit is formed is not particularly limited, but the inner layer substrate is provided with a carrier. A method of stacking the photosensitive resin film so that the carrier is on the outside is simple and preferable. The method of stacking the photosensitive resin film with a carrier on the inner layer substrate can be carried out using an apparatus such as a vacuum laminator and a hot roll laminator, for example, under conditions of a temperature of 100 to 130 ° C. and a pressure of 0.3 to 0.5 MPa.
In addition, there is no restriction | limiting in particular as a photosensitive resin composition, A well-known photosensitive resin composition can be used. In particular, in the present invention, when the photosensitive resin composition contains a component having a carboxyl group, the effect of the present invention is manifested. For example, as the photosensitive resin composition, the photosensitive resin composition described in Patent Document 5 (International Publication No. 2013/054790) can be used. Specifically, it contains (1) a binder polymer, (2) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (3) a photopolymerization initiator, and (1) the binder polymer is a carboxyl group. The photosensitive resin composition which has can be used. That is, the photosensitive resin layer is a layer containing (1) a binder polymer, (2) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (3) a photopolymerization initiator, and (1) The binder polymer may have a carboxyl group. Here, (1) the binder polymer is not particularly limited, and examples thereof include acrylic resins, styrene resins, epoxy resins, amide resins, amide epoxy resins, alkyd resins, phenol resins, and the like. From the viewpoint of alkali developability, an acrylic resin is preferable. (2) The photopolymerizable compound having at least one ethylenically unsaturated bond is not particularly limited. For example, a compound obtained by reacting a polyhydric alcohol with an α, β-unsaturated carboxylic acid. , A bisphenol A-based (meth) acrylate compound, a compound obtained by reacting a glycidyl group-containing compound with an α, β-unsaturated carboxylic acid, a urethane monomer such as a (meth) acrylate compound having a urethane bond, (meth) acrylic acid Examples include alkyl esters. (3) The photopolymerization initiator can be appropriately selected from known photopolymerization initiators.

(Photosensitive resin layer pattern (via post) formation step (b))
In the photosensitive resin layer pattern (via post) formation step (b), for example, a photo tool having a design in which circular patterns having a diameter of 60 μm or less (for example, 30 μm) are arranged at a pitch of 100 μm is arranged on a carrier, After the exposure, the carrier is removed and the unexposed portion is removed using a 1% by mass aqueous sodium carbonate solution or the like.
The exposure conditions are appropriately determined depending on the photosensitive resin composition to be used. For example, as a light source for actinic rays, ultraviolet rays and visible light such as carbon arc lamps, mercury vapor arc lamps, high pressure mercury lamps, xenon lamps, gas lasers such as argon lasers, solid state lasers such as YAG lasers, semiconductor lasers, etc. are effectively used. Use radiating material. As the wavelength of the actinic ray (exposure wavelength), for example, 340 to 430 nm is used.

(Insulating resin layer forming step (c))
Examples of the apparatus used for forming the insulating resin layer on the inner layer substrate include a vacuum laminator, a hot roll laminator, and a vacuum press. Among these, it is preferable to use a vacuum laminator from the viewpoints of moldability and mass productivity. For example, a method of pressurizing for 20 to 60 seconds under the conditions of a temperature of 60 to 140 ° C. and a pressure of 0.2 to 1 MPa using a vacuum laminator is preferable. As the vacuum laminator, for example, “MVLP500-600” (manufactured by Meiki Seisakusho Co., Ltd.) or the like is used.
Further, the substrate on which the insulating resin layer is formed may be subjected to heat treatment as necessary. Examples of the heat treatment method include a method of heating at a temperature of 140 to 190 ° C. for 15 to 120 minutes using a dryer.

(Cueing process (d))
In the cueing step (d), in order to remove a part of the insulating resin layer, for example, a polishing process using a ceramic roll, a sand blast process, a desmear process used in a conventional wiring board process, a wet blast process, a plasma process, etc. Can be used. Among these, it is preferable to use plasma treatment from the viewpoint of surface smoothness and mass productivity.
The conditions for the plasma treatment are not particularly limited as long as the post can be exposed. For example, using a plasma apparatus “Plasma Asher PB-1000S” (manufactured by Mori Engineering Co., Ltd.), pressure of 300 to 500 Pa, RF power of 300 to 500 W with an introduced gas of 10 to 20% oxygen gas and 2 to 8% argon gas. Plasma treatment can be performed for 5 to 20 minutes.

(Opening step (e))
In the opening forming step (e), examples of the method used to remove the via post include a known processing method using a plating resist stripping solution used for wiring formation and a known desmear used in a printed wiring board manufacturing step. A treatment method using a liquid can be used. From the viewpoint of mass productivity and adhesion between the insulating resin layer and a conductor circuit described later, it is preferable to use a desmear liquid. As the desmear liquid, a desmear liquid containing a permanganic acid aqueous solution is preferable.
As the desmear liquid, a commercially available desmear stock solution may be used, and for example, “Concentrate Compact CP” (manufactured by Atotech) or the like can be used.

(Conductor circuit forming step (f))
In the conductor circuit forming step (f), as a method for forming a conductor circuit in the insulating resin layer and the opening, a known conductor circuit forming method in the printed wiring board manufacturing step can be used. For example, a conventional semi-additive process can be used. As a conductor layer forming method in the semi-additive process, a sputtering method, electroless plating, CVD (Chemical Vapor Deposition), or the like can be used. From the viewpoint of price and mass productivity, the conductor layer is preferably formed by electroless plating. A commercially available electroless plating solution can be used. For example, an electroless copper plating solution manufactured by Atotech Co., Ltd. is used.

Hereinafter, although one aspect | mode of the manufacturing method of the multilayer printed wiring board of this invention is demonstrated concretely using FIGS. 2-12, it does not restrict | limit in particular in this.
First, a copper-clad laminate 1 (see FIG. 2 (a)) having copper foil (conductor layer) 2 on both surfaces as a support is prepared. Next, as shown in FIG. 2 (b), unnecessary portions of the copper foil 2 of the copper clad laminate 1 are removed by etching to form conductor circuits 2 a and 2 b, thereby obtaining a printed wiring board 10. The material of the circuit is not limited to copper.

Next, as shown in FIG. 3, the first photosensitive resin layer 3 made of the photosensitive resin composition is formed so as to cover the conductor circuits 2a and 2b (photosensitive resin layer forming step (a)). .
After that, by irradiating actinic rays through the mask pattern, a portion of the first photosensitive resin layer 3 that is not removed after the subsequent development processing is exposed, and the first photosensitive resin layer 3 in the exposed portion is photocured. .

  Next, by removing both surfaces of the first photosensitive resin layer 3 other than the exposed portion by development, the patterns 3a and 3b of the first photosensitive resin layer are formed on both surfaces of the printed wiring board as shown in FIG. (Photosensitive resin layer pattern (via post) forming step (b)). The patterns 3a and 3b of the first photosensitive resin layer are removed in an opening forming step (e) described later, and become fine openings formed in the insulating resin layer 4 (see FIG. 7).

After the development processing, as shown in FIG. 5, the insulating resin layer 4 made of the insulating resin composition is formed so as to cover the patterns 3a and 3b of the first photosensitive resin layer (insulating resin layer forming step (c )).
Next, the formed insulating resin layer 4 is thermally cured.

  Next, as shown in FIG. 6, by applying a desmear treatment, a part of the insulating resin layer 4 after thermosetting is removed to insulate predetermined portions of the patterns 3a and 3b of the first photosensitive resin layer. It exposes from the resin layer 4 (cueing process (d)). The cueing step (d) is not limited to the desmear process, and a technique such as wet blasting, dry etching, or polishing may be used.

  After the patterns 3a and 3b of the first photosensitive resin layer are exposed from the insulating resin layer 4, the patterns 3a and 3b of the first photosensitive resin layer exposed from the insulating resin layer 4 are removed by a desmear process. As shown in FIG. 7, the conductor circuits 2a and 2b are exposed (opening forming step (e)). Thus, the opening 4h is formed in the insulating resin layer 4. The shape of the opening is preferably circular and may be elliptical. The maximum diameter of the opening (R in FIG. 7) is preferably 60 μm or less.

Hereinafter, a semi-additive process will be described as one embodiment of the conductor circuit forming step (f). As shown in FIG. 8, the electroless plating is performed so as to cover the surface 4s of the insulating resin layer 4, the wall surface 4w of the insulating resin layer 4, and the exposed surfaces of the conductor circuits 2a and 2b. Thus, a seed layer (thin conductive layer) 5 is formed. Although there is no restriction | limiting in particular in the thickness of the seed layer 5, Usually, it is preferably 0.1-1 micrometer.
Next, a film-like photosensitive resin composition is adhered to both surfaces to form a second photosensitive resin layer, and then a phototool having a predetermined pattern is brought into close contact with each other, and exposure processing and development processing are performed. As shown in FIG. 2, the second photosensitive resin layers on both sides are patterned (second photosensitive resin layer pattern forming step).

  Next, as shown in FIG. 10, the wiring part 7 is formed by an electrolytic plating method such as copper electrolytic plating so as to cover at least a part of the seed layer 5. In this step, the wiring portion 7 is formed on the surface of the seed layer 5 other than the region where the patterns 6a and 6b of the second photosensitive resin layer are formed. In the region where the opening 4h is formed, the wiring portion 7 is formed on the seed layer 5 formed on the wall surface 4w and the surfaces of the conductor circuits 2a and 2b. The thickness of the wiring part 7 is preferably 1 to 20 μm. Thereafter, the patterns 6a and 6b of the second photosensitive resin layer are peeled off by a peeling solution to form wiring patterns 7a and 7b. Next, the seed layer 5 in the region where the wiring part 7 is not formed is removed by etching using an etching solution.

  Through the above steps, as shown in FIG. 11, a multilayer printed wiring board 100 having wiring portions (wiring patterns 7a and 7b) on the surface can be obtained. Furthermore, after repeating the series of steps from the photosensitive resin layer forming step to the seed layer removing step on both the front and back surfaces of the multilayer printed wiring board 100, a solder resist 8 is formed on the outermost layer, A multilayer printed wiring board 200 as shown in FIG. 12 can be obtained by forming the nickel / gold layer 9 by performing a plating process using an electrolytic nickel / gold plating solution or the like.

  Next, the present invention will be described in more detail with reference to the following examples, but these examples are not intended to limit the present invention in any way.

(Preparation Example 1) Preparation of Thermosetting Resin Composition (1) (a) As component, biphenylaralkyl novolak type epoxy resin “NC3000” (manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 275 g / eq, in the above formula (1) P = 1.7) 16.28 g was blended with 36.35 g of methyl ethyl ketone. As the component (b), phenol novolac resin “Phenolite (registered trademark) TD-2131” (manufactured by DIC Corporation, hydroxyl equivalent 104 g / eq) 1.33 g and aminotriazine-modified novolac type phenolic resin “Phenolite (registered) (Trademark) LA3018-50P "(manufactured by DIC Corporation) 6.66 g, and as a component (c), the surface of silica" SO-C2 "(manufactured by Admatechs Co., Ltd., average particle size: 0.5 μm) 38.2 g (solid content concentration: 35% by mass) of silica slurry which was treated with a system coupling agent “KBM-573” (manufactured by Shin-Etsu Chemical Co., Ltd.) and then dispersed in methyl ethyl ketone was added. To this, 0.05 g of triphenylphosphine 1,4-benzoquinone adduct “P2” (produced by Hokuko Chemical Co., Ltd.) as component (d), 0.42 g of “BYK310” (produced by BYK Chemie) as a leveling agent and antioxidant After adding 0.081 g of “Yoshinox BB” (manufactured by Mitsubishi Chemical Co., Ltd.) as an agent, mixing is performed using a disperser “Nanomizer” (manufactured by Yoshida Kikai Kogyo Co., Ltd.), and the thermosetting resin composition (1) ( A non-volatile content concentration of about 65% by mass and an inorganic filler content of 35% by mass in the non-volatile content were obtained.

Preparation Example 2 Preparation of Thermosetting Resin Composition (2) In Preparation Example 1, instead of triphenylphosphine 1,4-benzoquinone adduct “P2,” triphenyl phosphate “TPP” (Wako Pure Chemical Industries, Ltd.) A thermosetting resin composition (2) (non-volatile content of about 65% by mass, content of inorganic filler in non-volatile content of 35% by mass) was obtained in the same manner except that the company was used. .

Preparation Example 3 Preparation of Thermosetting Resin Composition (3) In Preparation Example 1, 1,4-benzoquinone addition of tri-n-butylphosphine instead of triphenylphosphine 1,4-benzoquinone adduct “P2” The thermosetting resin composition (3) (non-volatile content concentration of about 65% by mass, inorganic filler in non-volatile content) except that the body “TBP2” (made by Hokuko Chemical Co., Ltd.) was used. A content of 35% by mass) was obtained.

Preparation Example 4 Preparation of Thermosetting Resin Composition (4) In Preparation Example 1, instead of the phenol novolac resin “Phenolite (registered trademark) TD-2131”, the phenol novolak resin “Phenolite (registered trademark) TD2093Y” was prepared. The thermosetting resin composition (4) (non-volatile content concentration of about 65% by mass, inorganic filling in non-volatile content was carried out in the same manner except that a hydroxyl equivalent of 104 g / eq manufactured by DIC Corporation was used. A material content of 35% by mass was obtained.

(Preparation Example 5) Preparation of thermosetting resin composition (5) In Preparation Example 1, silica “UFP-40” (manufactured by Denki Kagaku Kogyo Co., Ltd.) was used instead of silica “SO-C2”. Were similarly operated to obtain a thermosetting resin composition (5) (non-volatile content of about 65% by mass, inorganic filler content in non-volatile content of 35% by mass).

Preparation Example 6 Preparation of Thermosetting Resin Composition (6) In Preparation Example 1, instead of biphenyl aralkyl novolak epoxy resin “NC3000”, biphenyl aralkyl novolak epoxy resin “NC3000-H” (Nippon Kayaku Co., Ltd.) The thermosetting resin composition (6) (non-volatile content concentration of about 65) was obtained in the same manner except that the company-made epoxy equivalent 288 g / eq, p = 2.8 in the formula (1) was used. Mass%, inorganic filler content 35 mass% in non-volatile content).

Preparation Example 7: Comparative Example Preparation of Thermosetting Resin Composition (7) In Preparation Example 1, instead of triphenylphosphine 1,4-benzoquinone adduct “P2”, 1-cyanoethyl-2-phenylimidazo The thermosetting resin composition (7) (non-volatile content concentration of about 65% by mass, non-volatile content) was performed in the same manner except that lime trimellitate “2PZCNS-PW” (manufactured by Shikoku Kasei Kogyo Co., Ltd.) was used. An inorganic filler content of 35% by mass was obtained.

Preparation Example 8: Comparative Example Preparation of Thermosetting Resin Composition (8) In Preparation Example 1, instead of triphenylphosphine 1,4-benzoquinone adduct “P2”, 2-phenylimidazole “2PZ” ( The thermosetting resin composition (8) (non-volatile content concentration of about 65% by mass, inorganic filler content in the non-volatile content is 35% by mass, except that Shikoku Kasei Kogyo Co., Ltd.) was used. )

Example 1
On a PET (polyethylene terephthalate) film “Therapy (registered trademark)” (made by Toray Film Processing Co., Ltd., thickness 38 μm) as a support, the thermosetting resin composition (1) obtained in Preparation Example 1 was obtained with a bar coater. After application, the film was dried using a dryer at 80 ° C. for 4 minutes to obtain an insulating resin film 1 having a support on one side and a thickness of 25 μm (excluding the thickness of the support).
Using the obtained insulating resin film 1, a substrate for evaluation was produced as follows, and post-removability was evaluated.

<Manufacture of evaluation substrate>
First, a copper clad laminate “MCL-E-679FG” (manufactured by Hitachi Chemical Co., Ltd.) in which a copper foil having a thickness of 12 μm was adhered to both surfaces was prepared. The thickness of the copper clad laminate was 400 μm. The copper surface was roughened with a CZ treatment liquid “MEC etch bond (registered trademark) CZ-8100” (manufactured by MEC Co., Ltd.) to manufacture an inner layer substrate.
[Photosensitive resin layer forming step (a)]
After heating the obtained inner layer substrate and raising the temperature to 80 ° C., a dry film resist “RY3325” (manufactured by Hitachi Chemical Co., Ltd., with carrier and protective layer) made of acrylic resin is placed on the copper surface of the inner layer substrate. Laminated. Lamination was performed under conditions of a temperature of 120 ° C. and a lamination pressure of 0.39 MPa so that the photosensitive resin layer was in close contact with the copper surface of the inner substrate while removing the protective layer. Subsequently, it cooled to room temperature and obtained the board | substrate with which the photosensitive resin layer and the carrier were laminated | stacked on the copper surface of the inner layer board | substrate. As a laminating apparatus, a batch type vacuum pressure laminator “MVLP-500” (manufactured by Meiki Seisakusho Co., Ltd.) was used.
[Via post forming step (b)]
A phototool having a design in which cylindrical patterns with a diameter of 30 μmφ were arranged at a pitch of 30 μm was placed on the carrier of the obtained multilayer substrate. The exposure is performed at an exposure of 200 mJ / cm ² using a parallel light exposure machine “EXM-1201” (manufactured by Oak Manufacturing Co., Ltd.) using a short arc UV lamp “AHD-5000R” (manufactured by Oak Manufacturing Co., Ltd.) as a light source. In a quantity, the photosensitive resin layer was exposed through a phototool and a support. For measurement of illuminance, an ultraviolet illuminometer “UV-350SN type” (manufactured by Oak Manufacturing Co., Ltd.) to which a 365 nm probe was applied was used.
After the exposure, the carrier is peeled off from the laminated substrate, the photosensitive resin layer is exposed, and a 1% by mass sodium carbonate aqueous solution is sprayed at 30 ° C. and 0.2 MPa using a developing machine “HMS” (manufactured by Uemura Kogyo Co., Ltd.). This removed the unexposed part. The development time was set to twice the shortest development time of each photosensitive resin composition. Thus, the board | substrate with a post pattern in which the via post was formed on the copper surface of the board | substrate was obtained.
Here, the shortest development time is a value obtained by measuring as follows. First, the laminated substrate was cut into a size of 30 mm × 30 mm to obtain a test piece. After peeling the carrier from this test piece, it was spray-developed at a pressure of 0.2 MPa using a 1% by mass aqueous sodium carbonate solution at 30 ° C., and the shortest that could be visually confirmed that the unexposed area was completely removed The time was defined as the shortest development time.
[Preparation of pattern-exposed laminated substrate, insulating resin layer forming step (c)]
The insulating resin film 1 was laminated on the substrate on which the via post was formed. Lamination was performed under the conditions of a temperature of 70 ° C. and a laminating pressure of 0.5 MPa so that the insulating film 1 was in close contact with the surface of the post-patterned substrate. Next, the substrate was semi-cured at a temperature of 160 ° C. to obtain a substrate in which an insulating resin film was laminated on a post-patterned substrate.
[Cueing step (d)]
The via post was exposed by subjecting the multilayer substrate with the post pattern to plasma treatment. The plasma treatment was performed by plasma irradiation for 25 minutes using a gas having an oxygen concentration of 16% and an argon concentration of 5%. The via post exposure was confirmed using a microscope “Digital Microscope VHX-2000” (manufactured by Keyence Corporation).
[Opening process (e)]
A substrate with a post pattern with exposed via posts was subjected to a swelling (sweller) treatment at 70 ° C. for 10 minutes, followed by desmear treatment at 70 ° C. for 30 minutes to obtain a substrate in which the via posts were removed and openings were formed. It was. About the removal property of a via post, it observed using the microscope "digital microscope VHX-2000" (made by Keyence Corporation), and evaluated it according to the following evaluation criteria. The results are shown in Table 1 and FIG.
(Evaluation criteria for via post removal)
A: No via post remains.
C: The via post remains.

(Example 2)
Except that the thermosetting resin composition (2) obtained in Preparation Example 2 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1.
(Example 3)
Except that the thermosetting resin composition (3) obtained in Preparation Example 3 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1.
Example 4
Except that the thermosetting resin composition (4) obtained in Preparation Example 4 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1.
(Example 5)
Except that the thermosetting resin composition (5) obtained in Preparation Example 5 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1.
(Example 6)
Except that the thermosetting resin composition (6) obtained in Preparation Example 6 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1.

(Comparative Example 1)
Except that the thermosetting resin composition (7) obtained in Preparation Example 7 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1 and FIG.
(Comparative Example 2)
Except that the thermosetting resin composition (8) obtained in Preparation Example 8 was used, the same operation as in Example 1 was performed, and the via post removability was observed and evaluated. The results are shown in Table 1.

  From Table 1, when a phosphorus hardening accelerator is used (Examples 1 to 6), the via post removal is good, but a basic imidazole hardening accelerator is used (Comparative Examples 1 and 2). ) Shows that the post is not completely removed (see the part circled in FIG. 14).

  Since the insulating resin film of the present invention is excellent in via post removability, it is useful as an insulating resin film for multilayer printed wiring boards obtained through a via forming step by removing a photosensitive resin layer.

Claims (9)

An insulating resin film formed using a thermosetting resin composition containing (a) an epoxy resin, (b) a phenol resin, (c) an inorganic filler, and (d) a phosphorus-based curing accelerator, An insulating resin film for a multilayer printed wiring board obtained through a via formation step by removing a conductive resin layer.   (D) The phosphorus curing accelerator is selected from the group consisting of organic phosphines, complexes of organic phosphines and organic boron, adducts of tertiary phosphines and quinone compounds, phosphonium salts, and thiocyanates of quaternary phosphines. The insulating resin film according to claim 1, which is at least one selected.   The insulating resin film according to claim 1 or 2, wherein the content of the inorganic filler (c) in the nonvolatile content of the thermosetting resin composition is 1 to 70 mass%.   (C) The insulating resin film according to any one of claims 1 to 3, wherein the inorganic filler is silica.   (C) The insulating resin film according to any one of claims 1 to 4, wherein the inorganic filler is a surface-treated silica. The (a) epoxy resin is a polyfunctional epoxy resin having an average of more than two epoxy groups in the molecule, or an epoxy resin represented by the following formula (1). The insulating resin film according to any one of 5.

(In the formula, p represents 1 to 5.)   The photosensitive resin layer is a layer containing (1) a binder polymer, (2) a photopolymerizable compound having at least one ethylenically unsaturated bond, and (3) a photopolymerization initiator, and ( 1) The insulating resin film according to any one of claims 1 to 6, wherein the binder polymer has a carboxyl group.   The insulating resin film with a support which has a support body in the single side | surface of the insulating resin film of any one of Claims 1-7.   The multilayer printed wiring board formed using the insulating resin film of any one of Claims 1-8.