JP5987329B2 - Manufacturing method of resin varnish - Google Patents

Description

  The present invention relates to a method for producing a specific resin varnish containing an organic filler.

Conventionally, efforts have been made to increase the rigidity of a resin (resin composition) obtained by solidifying a resin varnish by incorporating an inorganic filler into the resin varnish in the field of electronic materials.
Patent Document 1 discloses a technique of blending an inorganic filler into a resin as a technique for imparting low linear expansion to the resin. However, when the varnish is applied, there is still room for improvement, such as resin repelling and uneven coating.

  On the other hand, Patent Document 2 discloses a technique of blending an inorganic filler and an organic filler into a resin in the hope of improving the adhesion between the base material and the resin. However, the resin composition described in Patent Document 2 has no problem due to filler dispersibility in use in the printing field, but the filler dispersibility is not necessarily satisfactory in use in the electronic material field. It wasn't.

JP 2005-290029 A International Publication No. 2006/098409 Pamphlet

  A problem to be solved by the present invention is a resin having a high filler dispersibility, which enables formation of an insulating layer that contains an organic filler but provides low roughness, high peel strength, and high insulation reliability. It is to provide a method for producing a varnish.

  As a result of intensive studies, the present inventors have found that the above problem can be solved by applying a specific swelling process to the organic filler, and have completed the present invention.

That is, the present invention includes the following aspects.
[1] A method for producing a resin varnish comprising the following step 1).
Step 1) A step of swelling an organic filler with an organic solvent at least 3.5 times the amount of the organic filler (swelling step)
[2] The method for producing a resin varnish according to the above [1], further comprising the following step 2).
Step 2) Step of adding varnish raw material (excluding organic filler) to the swollen organic filler produced by the swelling step and mixing (mixing step)
[3] The method for producing a resin varnish according to the above [2], further comprising the following step 3).
Step 3) A step of dispersing the swollen organic filler in the mixed solution produced by the mixing step (dispersing step)
[4] The method for producing a resin varnish according to the above [3], further comprising the following step 4).
Step 4) A step of filtering the dispersion treatment liquid produced by the dispersion step (filtration step)
[5] The amount of the organic filler used in step 1) is 0.1% by mass or more and 10% by mass or less when the nonvolatile component of the resin varnish is 100% by mass. The method for producing a resin varnish according to any one of [2] to [4].
[6] The process for producing a resin varnish according to any one of the above [3] to [5], wherein the swelling organic filler is dispersed using a homogenizer in step 3).
[7] The method for producing a resin varnish according to any one of the above [4] to [6], wherein a filter having a filtration accuracy of 10 μm or less is used in the step 4).
[8] The method for producing a resin varnish according to the above [7], wherein the collection rate of the filter with respect to the 2 μm aggregate is 80% or more and the collection rate with respect to the 3 μm aggregate is 85% or more.
[9] The process for producing a resin varnish according to any one of the above [4] to [8], wherein the filtration pressure is 0.4 MPa or less in the step 4).
[10] The method for producing a resin varnish according to the above [9], wherein in step 4), the filtration pressure is 0.03 MPa or more.
[11] The method for producing a resin varnish according to any one of the above [1] to [10], wherein the step 1) is performed under low flow.
[12] The method for producing a resin varnish according to any one of the above [1] to [11], wherein the organic solvent in the step 1) is an aromatic hydrocarbon solvent.
[13] A resin varnish obtained by the method according to any one of [1] to [12].
[14] An adhesive film comprising the resin varnish according to [13].
[15] A prepreg comprising the resin varnish according to [13].
[16] A metal-clad laminate comprising the resin varnish according to [13].
[17] A multilayer printed wiring board comprising the resin varnish according to [13].
[18] The surface roughness (Ra value) of the surface of the insulating layer by the resin varnish described in [13] is 50 nm or more and 300 nm or less, and the peel strength of the insulating layer to the conductor layer is 0.53 kgf / cm or more. A multilayer printed wiring board characterized by being 5 kgf / cm or less.
[19] A semiconductor device using the multilayer printed wiring board according to [17] or [18].

  By subjecting the organic filler to a swelling step that absorbs an organic solvent of a specific amount or more, an insulating layer is formed that provides low roughness, high peel strength, and high insulation reliability after curing while containing the organic filler. A method for producing a resin varnish can be provided.

  The method for producing the resin varnish of the present invention is mainly characterized by having a step (swelling step) of swelling the organic filler with an organic solvent that is 3.5 times or more the amount of the organic filler.

Hereinafter, the manufacturing method of a resin varnish is explained in full detail sequentially.
<Step 1) Swelling step>
The organic filler is swollen with an organic solvent that is 3.5 times the amount of the organic filler. The “resin varnish” in the present invention means “a liquid resin composition capable of forming a coating film”. “Swell” means that the organic filler absorbs the organic solvent regardless of whether the organic filler is a crosslinked polymer or a non-crosslinked polymer. The organic filler obtained in this step and absorbing the organic solvent by 3.5 times or more is referred to as “swelling organic filler”.

(Organic filler)
The organic filler used in the present invention may be a resin or rubber particle having a crosslinked structure or a non-crosslinked resin or rubber particle used as a filler in an insulating layer of a multilayer printed wiring board, a solder resist, or the like. Although it can be used without limitation, crosslinked rubber particles are preferred from the standpoints of improving the mechanical strength of the cured product and stress relaxation effect.

  Specific examples of such 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, the outer shell layer is a glassy polymer and the inner core layer is a rubbery polymer. Examples include a three-layer structure in which the shell layer is a glassy polymer, the intermediate layer is a rubbery polymer, and the core layer is a glassy polymer. The glassy polymer is composed of, for example, a polymer of methyl methacrylate or styrene, and the rubbery polymer is composed of, for example, a butyl acrylate polymer (butyl rubber) or polybutadiene. Specific examples of the core-shell type rubber particles include Staphyloid AC3832, AC3816N, IM-401 (manufactured by Ganz Kasei Co., Ltd.), Metabrene KW-4426 (manufactured by Mitsubishi Rayon Co., Ltd.), F351 (Nippon Zeon Co., Ltd.). Manufactured) and the like. Specific examples of acrylonitrile butadiene rubber (NBR) particles include XER-91 (manufactured by JSR Corporation). Specific examples of styrene butadiene rubber (SBR) particles include XSK-500 (manufactured by JSR Corporation). Specific examples of the acrylic rubber particles include Methbrene W300A and W450A (manufactured by Mitsubishi Rayon Co., Ltd.). The organic filler can use 1 type (s) or 2 or more types.

  The average particle size of the organic filler is preferably in the range of 0.005 to 1 μm, and more preferably in the range of 0.2 to 0.6 μm. The average particle diameter of the organic filler can be measured using a dynamic light scattering method. For example, the organic filler is uniformly dispersed by ultrasonic waves in an appropriate organic solvent that does not dissolve the organic filler, and the particle size distribution of the organic filler is created on a weight basis using FPRA-1000 (manufactured by Otsuka Electronics Co., Ltd.). The median diameter is measured as an average particle diameter.

  The content of the organic filler in the finally obtained resin varnish is not particularly limited, but from the viewpoint of fully developing the effect of blending the organic filler, that is, crack prevention of the cured product, stress relaxation effect, When the nonvolatile component of the resin varnish is 100% by mass, 0.1% by mass or more is preferable, 0.5% by mass or more is preferable, more preferably 0.7% by mass or more, and particularly preferably 1% by mass or more. It is. In addition, the content of the organic filler in the resin varnish finally obtained is a resin varnish from the viewpoint of preventing the heat resistance and moisture resistance of the cured product obtained by drying and heat-curing the resin varnish from being reduced. When the non-volatile component is 100% by mass, it is preferably 10% by mass or less, and more preferably 4% by mass or less. The “content of the organic filler in the finally obtained resin varnish” typically corresponds to the content of the organic filler in the mixed solution produced through the step 2) described later. Therefore, the amount of the organic filler used in this step (step 1)) should be 0.1% by mass or more and 10% by mass or less with respect to 100% by mass of the mixed solution produced in step 2). Is preferred.

(Organic solvent)
The organic solvent used in this step is not particularly limited as long as it can be absorbed by the organic filler, and can be appropriately selected depending on the type of the organic filler. Specifically, solvent naphtha, toluene, xylene, etc. Aromatic hydrocarbon solvents, ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, acetate solvents such as ethyl acetate, butyl acetate, cellosolve acetate, propylene glycol monomethyl ether acetate, carbitol acetate, cellosolve, butyl carbitol, etc. Examples thereof include carbitol solvents, amide solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. Of these, aromatic hydrocarbon solvents are preferred, and solvent naphtha is particularly preferred from the standpoints of absorbability to organic fillers and coating properties of resin varnish. One organic solvent may be used, or two or more organic solvents may be mixed and used.

  The amount of the organic solvent to be absorbed by the organic filler is required to be 3.5 times or more of the organic filler on the mass basis of the organic filler. In view of achieving good dispersibility of the swelling organic filler in the resin varnish, the amount is preferably 3.6 times or more, more preferably 3.7 times or more, still more preferably 3.8 times or more. The amount is more preferably 9 times or more, more preferably 4.0 times or more, particularly preferably 4.1 times or more. On the other hand, the upper limit of the amount of the organic solvent absorbed by the organic filler is preferably 20 times or less, and 15 times the amount from the viewpoint of cost advantage while maintaining the desired effect by absorbing the organic solvent. The following is more preferable, 10 times or less is further preferable, 8 times or less is still more preferable, and 6 times or less is especially preferable.

  The temperature at which the organic solvent is absorbed into the organic filler is preferably 20 ° C. or higher, preferably 25 ° C. or higher, more preferably 30 ° C. or higher, and 35 ° C. or higher, from the viewpoint that absorption of the organic solvent into the organic filler proceeds efficiently. Is even more preferable, and 40 ° C. or higher is even more preferable. On the other hand, from the viewpoint of preventing the vapor pressure from increasing and the organic solvent from being easily evaporated, the temperature of the organic solvent is preferably 90 ° C. or lower, more preferably 80 ° C. or lower, still more preferably 75 ° C. or lower, 70 It is even more preferably not higher than 65 ° C, particularly preferably not higher than 65 ° C, particularly preferably not higher than 60 ° C.

  The time for allowing the organic filler to absorb the organic solvent can be appropriately set depending on the temperature selected, but in order to absorb and retain the organic solvent in a predetermined amount (that is, 3.5 times the amount of the organic filler) It is preferably 30 minutes or longer, more preferably 60 minutes or longer, still more preferably 90 minutes or longer, and even more preferably 120 minutes or longer. In addition, from the viewpoint of improving work efficiency, 10 hours or less is preferable, 9 hours or less is more preferable, and 8 hours or less is even more preferable.

  The swelling of the organic filler (that is, absorption of the organic solvent into the organic filler) is preferably performed under low flow. As used herein, “under low flow” includes “a stationary state and a state in which the swollen organic filler has flowed in a range in which adhesion loss does not occur”. The “under low flow” of the present invention is more preferably “substantially under standing”.

Specific embodiments capable of achieving “under low flow” of the present invention are as follows. The reaction apparatus is in a state where an organic filler and an organic solvent are charged.
Aspect 1) The reaction apparatus is allowed to stand.
Aspect 2) Shaking the reaction apparatus.
Aspect 3) Giving vibration to the reaction apparatus with ultrasonic waves or the like.
Aspect 4) Stir the contents of the reactor.

In order to achieve “under low flow” according to the present invention, any of the embodiments 1) to 4) may be used, but any one of the embodiments 1) to 3) is preferable, and the embodiment 1) Or, it is more preferable although it is embodiment 2), and embodiment 1) is particularly preferable.
However, in the case of the embodiment 4), there is no particular limitation as long as low flow can be achieved, but from the viewpoint that the obtained swelling organic filler adheres to the stirring blade and the can wall and is not lost, the upper limit value of the stirring speed is 30 rpm or less is preferable, 20 rpm or less is more preferable, 10 rpm or less is further preferable, 5 rpm or less is still more preferable, 2 rpm or less is especially preferable, and 1 rpm or less is especially preferable. Further, from the viewpoint that low flow can be reliably realized, the lower limit value of the stirring speed is preferably 0.01 rpm or more, more preferably 0.001 rpm or more, still more preferably 0.0001 or more, and particularly preferably 0 rpm or more. In the case of Aspect 3) and Aspect 2), as in Aspect 4), there is a preferable range as long as it adheres to the can wall and is not lost.

<Step 2) Mixing step>
A varnish raw material (except organic filler) is added to the swollen organic filler and mixed to prepare a mixed solution. Examples of varnish materials (excluding organic fillers) include epoxy resins, epoxy resin curing agents, curing accelerators, organic solvents, inorganic fillers, thermoplastic resins, flame retardants, and other additives.

(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, glycidylamine type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, linear aliphatic epoxy resin, alicyclic epoxy resin, heterocyclic ring Type epoxy resin, spiro ring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, naphthylene ether type epoxy resin, trimethylol type epoxy resin, etc. That. The epoxy resin may be used alone or in combination of two or more, but it is preferable to use 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. Furthermore, the epoxy resin which is an aromatic epoxy resin having two or more epoxy groups in one molecule and liquid at a temperature of 20 ° C., and three or more epoxy groups in one molecule has a temperature of 20 An embodiment containing an aromatic epoxy resin that is solid at ° C is preferred. The aromatic epoxy resin in the present invention means an epoxy resin having an aromatic ring skeleton in the molecule. By using a liquid epoxy resin and a solid epoxy resin in combination as the epoxy resin, the resin layer formed using the resin varnish has excellent flexibility. For this reason, the adhesive film which forms this resin layer on a support body turns into an adhesive film excellent in the handleability. Moreover, the breaking strength of the cured resin layer obtained by curing the resin layer formed using the resin varnish is improved. Therefore, the durability of the circuit board is improved by forming the cured resin layer as an insulating layer of the circuit board.

  As the liquid epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, and naphthalene type epoxy resin are preferable, and naphthalene type epoxy resin is more preferable. Specific examples include HP4032 (naphthalene type epoxy resin) manufactured by DIC Corporation, HP4032D (naphthalene type epoxy resin), jER828EL (bisphenol A type epoxy resin) manufactured by Mitsubishi Chemical Corporation, jER807 (bisphenol F type epoxy resin). ), JER152 (phenol novolac type epoxy resin), and the like. These can use 1 type (s) or 2 or more types.

  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, naphthylene ether type epoxy resin are preferable. A tetrafunctional naphthalene type epoxy resin, a biphenyl type epoxy resin, and a naphthylene ether type epoxy resin are more preferable. Specific examples include HP-4700 (tetrafunctional naphthalene type epoxy resin), N-690 (cresol novolac type epoxy resin), N-695 (cresol novolac type epoxy resin), HP-7200 (di-type) manufactured by DIC Corporation. Cyclopentadiene type epoxy resin), EXA7311 (naphthylene ether type epoxy resin), EXA7310 (naphthylene ether type epoxy resin), EXA7311-G3 (naphthylene ether type epoxy resin), EPPN-502H manufactured by Nippon Kayaku Co., Ltd. (Trisphenol epoxy resin), 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) Nylon type epoxy resin), ESN475 (naphthol novolak type epoxy resin) manufactured by Nippon Steel Chemical Co., Ltd., ESN485 (naphthol novolak type epoxy resin), YX4000H (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation, etc. Can be mentioned.

  When a liquid epoxy resin and a solid epoxy resin are used in combination as the epoxy resin, the amount ratio of the solid resin to the liquid resin (liquid resin amount: solid resin amount) is 1: 0.1 to 1: 2 by mass ratio. A range is preferred. If the ratio of the liquid epoxy resin is too much beyond this range, the adhesiveness becomes high when the resin varnish is used in the form of an adhesive film, and the tendency to generate voids decreases during vacuum lamination. is there. Moreover, there exists a tendency for the peelability of a protective film and a support film to fall at the time of vacuum lamination, and the heat resistance after hardening to fall. Moreover, it exists in the tendency for sufficient breaking strength to be hard to be obtained in the hardened | cured material of a resin composition. On the other hand, if the ratio of the solid epoxy resin is too large beyond this range, sufficient flexibility cannot be obtained when using it in the form of an adhesive film, the handleability is lowered, and the flow is sufficient when laminating. There is a tendency that it is difficult to obtain.

  Epoxy resin is used in combination with a curing agent that cures it. The content of the epoxy resin in the resin varnish is preferably 5 to 50% by mass, more preferably 10 to 45% by mass, particularly preferably 15 to 40% by mass, most preferably 100% by mass of the nonvolatile component of the resin varnish. Is 20-35 mass%.

(Epoxy resin curing agent)
The epoxy resin curing agent is not particularly limited as long as it has a function of curing the epoxy resin, but is preferably a phenol curing agent, a naphthol curing agent, an active ester curing agent, a benzoxazine curing agent, or a cyanate. Ester-based curing agents and the like. The epoxy resin curing agent may be used alone or in combination of two or more.

  As a phenol type hardening | curing agent and a naphthol type | system | group hardening | curing agent, from a heat resistant and water-resistant viewpoint, the phenol type hardening | curing agent which has a novolak structure, and the naphthol type hardening | curing agent which has a novolak structure are preferable. Examples of commercially available products include MEH-7700, MEH-7810, MEH-7785 (Maywa Kasei Co., Ltd.), NHN, CBN, GPH (Nippon Kayaku Co., Ltd.), SN170, SN180, SN190, SN475, SN485, SN495, SN375, SN395 (manufactured by Toto Kasei Co., Ltd.), LA7052, LA7054 (manufactured by DIC Corporation), and the like.

  Examples of the active ester curing agent include EXB-9460, HPC8000 (manufactured by DIC Corporation), DC808, and YLH1030 (manufactured by Mitsubishi Chemical Corporation). Examples of the benzoxazine-based curing agent include HFB2006M (manufactured by Showa Polymer Co., Ltd.), Pd, Fa (manufactured by Shikoku Kasei Kogyo Co., Ltd.), and the like. Specific examples of the cyanate ester-based curing agent include, for example, bisphenol A dicyanate, polyphenol cyanate (oligo (3-methylene-1,5-phenylene cyanate)), and 4,4′-methylenebis (2,6-dimethylphenyl cyanate). 4,4′-ethylidenediphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis (4-cyanate) phenylpropane, 1,1-bis (4-cyanatephenylmethane), bis (4-cyanate-3) , 5-dimethylphenyl) methane, 1,3-bis (4-cyanatephenyl-1- (methylethylidene)) benzene, bis (4-cyanatephenyl) thioether, bis (4-cyanatephenyl) ether, etc. Resin, phenol novolac Polyfunctional cyanate resins derived from cresol novolac, these cyanate resins and partially triazine of prepolymer. Commercially available cyanate ester-based curing agents include phenol novolac type polyfunctional cyanate ester resin ("PT30" manufactured by Lonza Japan Co., Ltd., cyanate equivalent 124) and some or all of bisphenol A dicyanate, which are triazine. And a prepolymer (“BA230” manufactured by Lonza Japan Co., Ltd., cyanate equivalent 232) and the like.

  The epoxy resin curing agent may be used alone or in combination of two or more. In the epoxy resin curing agent, the ratio of the total number of epoxy groups in the epoxy resin and the total number of reactive groups in the epoxy resin curing agent is 1: 0.4 to 1: 2, where the total number of epoxy groups is 1. It is preferably used in an amount, and more preferably in an amount of 1: 0.5 to 1: 1.5. The total number of epoxy groups is a value obtained by dividing the solid content mass of each epoxy resin by the epoxy equivalent for all epoxy resins, and is a reactive group (active hydroxyl group, active ester group, etc.) of the epoxy curing agent. The total number of) is a value obtained by totaling the values obtained by dividing the solid mass of each curing agent by the reactive group equivalent for all curing agents. When content of a hardening | curing agent satisfy | fills this preferable range, there exists a tendency for the heat resistance of the hardened | cured material of the resin composition formed from a resin varnish to become enough.

(Curing accelerator)
Examples of the curing accelerator include organic phosphine compounds, imidazole compounds, amine adduct compounds, tertiary amine compounds, and the like. Specific examples of the organic phosphine compound include TPP, TPP-K, TPP-S, and TPTP-S (trade name of Hokuko Chemical Co., Ltd.). Specific examples of the imidazole compound include Curazole 2MZ, 2E4MZ, C11Z, C11Z-CN, C11Z-CNS, C11Z-A, 2MZ-OK, 2MA-OK, 2PHZ (trade names of Shikoku Kasei Kogyo Co., Ltd.). . Specific examples of the amine adduct compound include Novacure (trade name of Asahi Kasei Kogyo Co., Ltd.) and Fuji Cure (trade name of Fuji Kasei Kogyo Co., Ltd.). Specific examples of the tertiary amine compound include 1,8-diazabicyclo (5,4,0) undecene-7 (DBU).

  The content of the curing accelerator is preferably in the range of 0.1 to 5% by mass when the total amount of nonvolatile components of the epoxy resin and the epoxy resin curing agent is 100% by mass. You may use a hardening accelerator 1 type or in mixture of 2 or more types.

(Organic solvent)
Examples of the organic solvent include aromatic hydrocarbon solvents such as solvent naphtha, toluene and xylene; ether solvents such as dioxane, tetrahydrofuran, butyl ether, butyl ethyl ether, diglyme and triglyme; acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone. , 2-heptanone, 2-octanone, ketone solvents such as isophorone; ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, 2-methoxypropyl acetate, cellosolve acetate, carbitol acetate, γ- Ester solvents such as butyrolactone and methyl 2-hydroxypropanoate; methyl alcohol, ethyl alcohol, n-propyl alcohol Alcohol solvents such as isopropanol and butanol; Monoether solvents such as alkylene glycol such as ethylene glycol monomethyl ether and propylene glycol monomethyl ether; Carbitol solvents such as cellosolve and butyl carbitol; Amides such as dimethylacetamide and dimethylformamide A solvent is mentioned.

(Inorganic filler)
Examples of inorganic fillers include silica, alumina, barium sulfate, talc, clay, mica powder, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum borate, barium titanate, and titanium. Examples include strontium acid, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, barium zirconate, and calcium zirconate. Among these, silica such as amorphous silica, fused silica, crystalline silica, and synthetic silica is particularly preferable. preferable. One or more inorganic fillers can be used. The silica is preferably spherical silica having a shape advantageous for dispersibility in the resin varnish, and the average particle diameter is preferably in the range of 0.01 μm to 2 μm, and in the range of 0.05 μm to 1.5 μm. More preferred. When the average particle size is less than 0.01 μm, the specific surface area of the particles increases, the cohesiveness increases, and it becomes difficult to obtain uniform dispersibility. When the average particle size exceeds 2 μm, fine wiring is formed. Tend to be difficult to do.

  The average particle size of the inorganic filler can be measured by a laser diffraction / scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis with a laser diffraction particle size distribution measuring device, and the median diameter can be measured as the average particle diameter. As the measurement sample, an inorganic filler dispersed in water by ultrasonic waves can be preferably used. As a laser diffraction type particle size distribution measuring apparatus, LA-500 manufactured by Horiba, Ltd. can be used.

  Inorganic fillers are γ-aminopropylmethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, N for improving the moisture resistance of the resin layer and the cured product, dispersibility in the resin varnish, and the like. -Aminosilane coupling agents such as phenylaminopropyltrimethoxysilane, N-2 (aminoethyl) aminopropyltrimethoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ- Epoxysilane coupling agents such as glycidoxypropylmethyldiethoxysilane, 4-glycidylbutyltrimethoxysilane, (3,4-epoxycyclohexyl) ethyltrimethoxysilane; γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyl Triethoxy Mercaptosilane coupling agents such as orchid; silane coupling agents such as methyltrimethoxysilane, octadecyltrimethoxysilane, phenyltrimethoxysilane, methacryloxypropyltrimethoxysilane, imidazolesilane, imidazolinesilane, triazinesilane; hexamethyl Organosilazan compounds such as disilazane, hexaphenyldisilazane, trisilazane, cyclotrisilazane, 1,1,3,3,5,5-hexamethylcyclotrisilazane; butyl titanate dimer, titanium octylene glycolate, diisopropoxy Titanium bis (triethanolaminate), dihydroxy titanium bis lactate, dihydroxy bis (ammonium lactate) titanium, bis (dioctyl pyrophosphate) ethylene Titanate, bis (dioctylpyrophosphate) oxyacetate titanate, tri-n-butoxy titanium monostearate, tetra-n-butyl titanate, tetra (2-ethylhexyl) titanate, tetraisopropyl bis (dioctyl phosphite) titanate, tetraoctyl bis (Ditridecyl phosphite) titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate, isopropyl trioctanoyl titanate, isopropyl tricumyl phenyl titanate, isopropyl triisostearoyl titanate, isopropyl iso Stearoyl diacryl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl tri (dioctyl phosphate) Treated with one or more surface treatment agents such as titanate coupling agents such as titanate, isopropyltridodecylbenzenesulfonyl titanate, isopropyltris (dioctylpyrophosphate) titanate, isopropyltri (N-amidoethyl / aminoethyl) titanate May be. In particular, aminosilane coupling agents, epoxysilane coupling agents, and mercaptosilane coupling agents are preferred.

  The content of the inorganic filler in the resin varnish is not particularly limited, but from the viewpoint of preventing the mechanical strength of the cured product from being lowered, when the nonvolatile component of the resin varnish is 100% by mass, the content is 85% by mass or less. More preferably, it is 80 mass% or less, Most preferably, it is 75 mass% or less. From the viewpoint of sufficiently reducing the coefficient of thermal expansion of the cured product, when the nonvolatile component of the resin varnish is 100% by mass, it is preferably 20% by mass or more, more preferably 30% by mass or more, and particularly preferably 40% by mass. % Or more, and most preferably 50% by mass or more.

  The inorganic filler is preferably made into a slurry and then used for the preparation of a resin varnish (mixed solution). Slurry is obtained by dispersing the inorganic filler in an organic solvent to make it substantially mud. This slurry can be obtained, for example, by dispersing an inorganic filler in a dry state in a solvent using various apparatuses (stirring apparatus, dispersing apparatus, emulsifying apparatus, etc.) described later. In order to avoid caking of the inorganic filler during storage, the content of the inorganic filler in the slurry is preferably 80% by mass or less, and more preferably 75% by mass or less when the entire slurry is 100% by mass. Further, in order to facilitate the adjustment of the viscosity of the resin varnish during coating of the film, the content of the inorganic filler in the slurry is preferably 40% by mass or more, preferably 50% by mass or more when the entire slurry is 100% by mass. Is more preferable. In addition, caking means that the inorganic filler in a solvent hardens | cures and becomes an aggregate, and the lump of an inorganic filler arises in a solvent.

  As the organic solvent used for the slurry, the above-mentioned organic solvent as a varnish raw material (excluding the organic filler) can be used. Among these, polar organic solvents are preferable, ketone solvents are more preferable, and methyl ethyl ketone (hereinafter also abbreviated as “MEK”) is particularly preferable.

(Thermoplastic resin)
Examples of the thermoplastic resin include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamideimide resin, polyethersulfone resin, and polysulfone resin. One kind or two or more kinds of thermoplastic resins can be used. The content of the thermoplastic resin in the resin varnish is preferably 0.5 to 60% by mass, more preferably 3 to 50% by mass, when the nonvolatile component of the resin varnish is 100% by mass. If it is less than 0.5% by mass, the viscosity of the resin varnish tends to be low and it becomes difficult to form a resin composition layer having a uniform thickness and properties. If it exceeds 60% by mass, the melt viscosity of the film is high. Therefore, the embedding property in the recesses between the wirings on the surface of the circuit board having the wiring pattern when the films are laminated tends to be lowered. The 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 in the range of 20,000 to 60,000. Is more preferable. The weight average molecular weight is measured by gel permeation chromatography (GPC) method (polystyrene conversion). Specifically, the weight average molecular weight by the GPC method is LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, and Shodex K-800P / K-804L / K- manufactured by Showa Denko KK as a column. 804 L can be measured at a column temperature of 40 ° C. using chloroform or the like as a mobile phase, and can be calculated using a standard polystyrene calibration curve.

  Examples of the phenoxy resin include bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolak skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, Examples thereof include those having one or more skeletons selected from a trimethylcyclohexane skeleton. You may use a phenoxy resin 1 type or in mixture of 2 or more types. The terminal of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Examples of commercially available products include 1256, 4250 (bisphenol A skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation, YX8100 (bisphenol S skeleton-containing phenoxy resin) manufactured by Mitsubishi Chemical Corporation, and YX6954 (bisphenol manufactured by Mitsubishi Chemical Corporation). Acetophenone skeleton-containing phenoxy resin), FX280 and FX293 manufactured by Nippon Steel Chemical Co., Ltd., YL7553, YL6794, YL7213, YL7290, and YL7482 manufactured by Mitsubishi Chemical Corporation.

  Specific examples of the polyvinyl acetal resin include those manufactured by Denki Kagaku Kogyo Co., Ltd., electrified butyral 4000-2, 5000-A, 6000-C, 6000-EP, Sekisui Chemical Co., Ltd., ESREC BH series, BX series, and KS. Series, BL series, BM series and the like. Specific examples of the polyimide resin include polyimide “Rika Coat SN20” and “Rika Coat PN20” manufactured by Shin Nippon Rika Co., Ltd. Also, a linear polyimide obtained by reacting a bifunctional hydroxyl group-terminated polybutadiene, a diisocyanate compound and a tetrabasic acid anhydride (as described in JP 2006-37083 A), a polysiloxane skeleton-containing polyimide (JP 2002-2002). And modified polyimides such as those described in JP-A No. 12667 and JP-A No. 2000-319386. Specific examples of the polyamide-imide resin include polyamide-imide “Vilomax HR11NN” and “Vilomax HR16NN” manufactured by Toyobo Co., Ltd. In addition, modified polyamideimides such as polysiloxane skeleton-containing polyamideimides “KS9100” and “KS9300” manufactured by Hitachi Chemical Co., Ltd. may be mentioned. Specific examples of the polyethersulfone resin include polyethersulfone “PES5003P” manufactured by Sumitomo Chemical Co., Ltd. Specific examples of the polysulfone resin include polysulfone “P1700” and “P3500” manufactured by Solvay Advanced Polymers Co., Ltd.

(Flame retardants)
Examples of the flame retardant include an organic phosphorus flame retardant, an organic nitrogen-containing phosphorus compound, a nitrogen compound, a silicone flame retardant, and a metal hydroxide. You may use a flame retardant 1 type or in mixture of 2 or more types. Examples of organophosphorus flame retardants include phosphine compounds such as HCA, HCA-HQ, and HCA-NQ manufactured by Sanko Co., Ltd., phosphorus-containing benzoxazine compounds such as HFB-2006M manufactured by Showa Polymer Co., Ltd., and Ajinomoto Fine Techno. Reefos 30, 50, 65, 90, 110, TPP, RPD, BAPP, CPD, TCP, TXP, TBP, TOP, KP140, TIBP, PPQ manufactured by Hokuko Chemical Co., Ltd., Clariant Phosphorus ester compounds such as OP930 manufactured by Daihachi Chemical Co., Ltd., PX200 manufactured by Daihachi Chemical Co., Ltd., phosphorus-containing epoxy resins such as FX289 manufactured by Toto Kasei Co., Ltd., and FX310, and phosphorus-containing phenoxy such as ERF001 manufactured by Toto Kasei Co., Ltd. Examples thereof include resins. Examples of organic nitrogen-containing phosphorus compounds include phosphate ester compounds such as SP670 and SP703 manufactured by Shikoku Kasei Kogyo Co., Ltd., SPB-100, SPS-100, SPE-100, and SPH-100 manufactured by Otsuka Chemical Co., Ltd. Phosphazene compounds such as As the metal hydroxide, magnesium hydroxide such as UD65, UD650, UD653 manufactured by Ube Materials Co., Ltd., B-30, B-325, B-315, B-308, B manufactured by Sakai Kogyo Co., Ltd. And aluminum hydroxide such as -303 and UFH-20. The content of the flame retardant in the resin varnish is not particularly limited, but is preferably 0.5 to 10% by mass, more preferably 1 to 9% by mass, particularly preferably when the nonvolatile component of the resin varnish is 100% by mass. Is 1.5-8 mass%.

(Other ingredients)
In addition to the above-described components, the resin varnish may optionally contain a thermosetting resin (excluding an epoxy resin), an organometallic compound, various additives, and the like.

Examples of thermosetting resins (excluding epoxy resins) include xylene resins, thermosetting polyimide resins, bismaleimide resins, and the like.
Examples of organometallic compounds include organic copper compounds such as copper (II) acetylacetonate, organic zinc compounds such as zinc (II) acetylacetonate, and organic such as cobalt (II) acetylacetonate and cobalt (III) acetylacetonate. A cobalt compound etc. are mentioned. The addition amount of the organometallic compound is preferably in the range of 10 to 500 ppm, preferably 25 to 200 ppm in terms of metal with respect to the cyanate ester resin. The organometallic compound may be used alone or in combination of two or more.

  Examples of the resin additive include powders such as silicone powder, nylon powder, and fluororesin powder, thickeners such as Orben and Benton, silicone-based, fluorine-based, and polymer-based antifoaming agents or leveling agents, Examples include adhesion imparting agents such as silane coupling agents, triazole compounds, thiazole compounds, triazine compounds, porphyrin compounds, and colorants such as phthalocyanine blue, phthalocyanine green, iodin green, disazo yellow, and carbon black. it can.

  The mixing in this step (step 2) is preferably performed using a heating and stirring device. Specific examples of the heating and stirring apparatus include T.I. K homomixer, T.W. K. Homo disperse, T.W. K. Combimix, T. K. Hibis Disper Mix (above, product name manufactured by Primix Co., Ltd.), CLEARMIX (product name manufactured by M Technique Co., Ltd.), vacuum emulsification stirrer (product name manufactured by Mizuho Industry Co., Ltd.), vacuum mixing device “Nerimaze” DX "(trade name, manufactured by Mizuho Industry Co., Ltd.), BDM twin screw mixer, CDM concentric twin screw mixer, PD mixer (above, trade name, manufactured by Inoue Seisakusho Co., Ltd.), and the like. Of these, a heating and stirring device having a high-speed rotary blade such as a homomixer or a disper blade and a stirring blade is preferable in order to obtain a uniform mixed state more quickly. The heating temperature is preferably 30 ° C to 80 ° C, and more preferably 35 ° C to 70 ° C. When mixing is performed at such a heating temperature, particularly when the thermosetting resin contains a solid resin, the solid thermosetting resin quickly dissolves in the organic solvent, and the uniformity of the properties is improved. A high resin varnish can be produced efficiently. The heating and stirring device is not limited to a type having a fixed heating mechanism such as a general jacket or coil, and may be a type having a movable heating mechanism such as a throwing heater.

  The viscosity of the mixed solution is preferably 10 to 1000 mPa · s, more preferably 100 to 500 mPa · s. If the viscosity is too high, the liquid viscosity suppresses the diffusion of particles at the collision site and tends to result in non-uniform dispersion as a whole. The viscosity can be measured with a rotational viscometer such as an E-type viscometer.

  When preparing the resin varnish containing an inorganic filler, it is preferable to mix an inorganic filler using a heating stirring apparatus with a swelling organic filler and a thermosetting resin.

  When the curing agent is reactive at low temperature, the swelling organic filler and the thermosetting resin are mixed under heating and then cooled to room temperature, and the curing agent is added to the cooled mixed solution and further stirred ( It is preferable to perform mixing.

  In addition, when an epoxy resin is used as the thermosetting resin and the epoxy resin contains a solid epoxy resin, an inorganic filler slurry is used as the inorganic filler, and the solid epoxy resin is previously dissolved in the inorganic filler slurry. It is preferable to use it for the preparation of a mixed solution after that. In addition, thermoplastic resins, flame retardants and other additives may be mixed together with swelling organic fillers, thermosetting resins, etc., but mixed and mixed in a dispersion treatment liquid after organic filler dispersion treatment described below. It may be a liquid.

<Process 3) Dispersion process>
The swollen organic filler in the mixed solution produced by the mixing step (step 2)) is dispersed to prepare a dispersion treatment solution. The prepared dispersion treatment liquid may be used as a resin varnish as it is. It is particularly preferable to disperse the swollen organic filler using a means such as a homogenizer, a bead mill, or an ultrasonic wave. Here, “dispersion of the swollen organic filler” means that the swollen organic filler is dispersed in the form of primary particles. The homogenizer is a high-speed rotating type that disperses particles by shearing energy from a high-speed rotating blade, or a high-pressure type that disperses particles by generating collision energy, shearing energy, and cavitation due to high-pressure and pressure transfer of raw materials. The bead mill disperses particles by physical energy that causes the beads to collide. Ultrasonic waves are used to pulverize agglomerates by irradiating them with ultrasonic waves. Of these, a homogenizer is preferable, and a high-pressure homogenizer is more preferable. When the mixed liquid obtained through the step 2) contains an inorganic filler, the inorganic filler is dispersed together with the swollen organic filler in this step.

  As the high-pressure homogenizer, it is preferable that the material of the portion where the organic filler or the inorganic filler collides at high pressure is made of tungsten carbide or diamond in order to prevent foreign matter from being mixed due to collision wear. The high-pressure homogenizer is not a batch-type dispersion method but a continuous dispersion method, which can improve productivity and reduce the risk of organic solvent vapor radiating, reducing the cost and environmental burden. You can also Specific examples of the high pressure homogenizer include a high pressure homogenizer manufactured by Sanwa Engineering Co., Ltd., a high pressure homogenizer manufactured by Izumi Food Machinery Co., Ltd., and a high pressure homogenizer manufactured by Niro Soabi (Italy). The dispersion pressure of the high-pressure homogenizer is preferably in the range of 10 to 300 MPa, more preferably in the range of 15 to 100 MPa, still more preferably in the range of 20 to 60 MPa, and still more preferably in the range of 20 to 40 MPa. If the dispersion pressure is too low, the dispersion treatment tends to be insufficient. If it is too high, the liquid temperature of the liquid mixture rises, the components in the liquid mixture react, and the shape of the organic filler or inorganic filler changes. There is a tendency. Moreover, 1000-10000 rpm is preferable, as for the rotation speed of a homogenizer, 2000-9000 rpm is more preferable, 3000-8000 rpm is still more preferable, 4000-7000 rpm is still more preferable. In order to suppress the reaction of the components in the mixed liquid, the liquid temperature after the dispersion treatment is preferably 60 ° C. or lower. Moreover, it is preferable to make a liquid temperature rapidly 40 degrees C or less using a cooling device after a dispersion process.

  During the dispersion treatment, the temperature of the mixed solution rises. Therefore, when producing a resin varnish containing a curing accelerator, the curing accelerator is not mixed with the swollen organic filler, the thermosetting resin, etc. at the time of preparation of the previous mixed solution, and the mixing after the dispersion treatment is performed. It is preferable to mix with the liquid. As an apparatus for mixing the mixed solution after the dispersion treatment and the curing accelerator, for example, a known stirring and mixing apparatus including a disper blade, a turbine blade, a paddle blade, a propeller blade, an anchor blade, and the like can be used. Specific examples of the stirring and mixing apparatus include planetary mixers, trimixes, butterfly mixers (above, product names manufactured by Inoue Seisakusho Co., Ltd.), VMIX stirring tanks, Max Blend, SWIXER mixing systems (above, made by Izumi Food Machinery Co., Ltd.). Trade name), Hi-F mixer (trade name, manufactured by Soken Technics Co., Ltd.), jet agitator (trade name, manufactured by Shimazaki Corporation), and the like. Moreover, the heating and stirring apparatus described in the above section <Process 2) Mixing process> can also be used.

  In order to sufficiently perform the dispersion treatment, the dispersion treatment time is preferably 10 to 120 minutes, more preferably 20 to 90 minutes, and particularly preferably 30 to 70 minutes.

  In addition, as a varnish raw material (excluding organic filler) that can be used for the resin varnish after the dispersion step, a thermosetting resin, an inorganic filler, an organic solvent, a thermoplastic resin, a flame retardant, and other additives are optionally included. The dispersion process may be repeated.

<Step 4) Filtration step>
The dispersion treatment liquid produced by the above step (step 3)) is used to remove foreign matters and coarse particles (organic filler aggregates, organic filler and inorganic filler composite aggregates, inorganic filler aggregates, etc.) in the liquid. Therefore, it is preferable to filter. A known method can be used as the filtration method. For example, the dispersion treatment liquid is fed using a metering pump or a pressurized tank, and filtered by passing it alone or continuously through a cartridge filter, a capsule filter or the like. The filtration pressure (differential pressure) at that time is preferably 0.4 MPa or less, more preferably 0.3 MPa or less, still more preferably 0.2 MPa or less, still more preferably 0.15 MPa or less, so that the filter mesh does not open. 0.1 MPa or less is particularly preferable, and 0.05 MPa or less is particularly preferable. On the other hand, 0.03 MPa or more is preferable in order to prevent the discharge flow rate from being lowered and the productivity from being deteriorated. Moreover, although a well-known thing can be used for a metering pump, a thing with few pulsations is preferable in order to keep filtration pressure constant. The pore size of the filtration filter, that is, the filtration accuracy is preferably 10 μm or less, and more preferably 5 μm or less. In addition, when the dust collection capability of the filter is too high, it takes too much filtration time and tends to be inefficient. Therefore, the filtration accuracy of the filtration filter to be used is preferably 0.5 μm or more. Moreover, you may perform this process in multiple times.

  Further, in order to efficiently remove the aggregates by this step and improve the insulating properties of the insulating layer, the collection rate of the filter with respect to the aggregate of 2 μm is preferably 80% or more, and 85% or more. It is more preferable. Moreover, it is preferable that the collection rate of the filter with respect to a 3 micrometer aggregate is 85% or more, It is more preferable that it is 90% or more, It is still more preferable that it is 95% or more. The collection rate of the filter is measured by filtering a suspension of JIS test powder, APPIE standard powder, commercially available Latex Beads, etc., dispersed in advance in a solvent, and using a Coulter counter or the like. It can be calculated by the following formula. In addition, the solvent at this time is not limited, and an aqueous or non-aqueous solvent can be used. However, in order to accurately grasp the ability of the filter, select a solvent having a viscosity comparable to the varnish viscosity. Is preferred.

  Collection rate (%) = ((dust amount before filtration−dust amount after filtration) / dust amount before filtration) × 100

  Moreover, it is preferable to filter immediately before using the resin varnish of this invention from a viewpoint of the insulation improvement of an insulating layer. The time from this step to the use of the resin varnish is preferably within 24 hours, more preferably within 12 hours, further preferably within 6 hours, still more preferably within 3 hours, even more preferably within 1 hour, and 30 minutes. Is particularly preferred, within 10 minutes is particularly preferred, and within 1 minute is even more preferred.

  In steps 1), 2), 3), and 4), epoxy resin, epoxy resin curing agent, curing accelerator, organic solvent, and inorganic are used as varnish raw materials (excluding organic filler) to such an extent that the effects of the present invention are not impaired. A filler, a thermoplastic resin, a flame retardant, and other additives may be added separately or partially.

<Formation of insulating layer>
The resin varnish of the present invention is obtained through “steps 1), 2) and 3) when referring to“ obtained through steps 1) and 2) ”(hereinafter referred to as“ resin varnish A ”). "(Hereinafter referred to as resin varnish B)" may refer to "obtained through steps 1), 2), 3) and 4)" (hereinafter referred to as resin varnish C). Resin varnish B and resin varnish C are preferable, and resin varnish C is particularly preferable from the viewpoint of being suitable for higher performance applications.

  The use of the resin varnish of the present invention is not particularly limited, but is an adhesive film, a sheet-like laminated material such as a prepreg, an insulating layer of a circuit board (laminated board, multilayer printed wiring board, etc.), a solder resist, an underfill material, and die bonding. It can be used in a wide range of applications where a resin composition is required, such as materials, semiconductor sealing materials, hole-filling resins, and component-filling resins. Furthermore, the resin varnish of the present invention can be applied to a support and dried to form a resin composition layer to form an adhesive film. Moreover, a resin varnish can be impregnated into a sheet-like fiber base material to obtain a prepreg. Although the resin varnish of the present invention can be directly applied to a circuit board, dried and thermally cured to form an insulating layer, it is industrially used for forming an insulating layer in the form of an adhesive film or prepreg. The insulating layer formed by drying and curing the resin varnish obtained by the production method of the present invention has a roughened surface that provides high adhesion to the conductor layer while having a low roughness by a roughening treatment. The insulating layer can be formed and provides high insulation reliability.

  When the resin varnish of the present invention is applied to the formation of an insulating layer of such a circuit board, the resin varnish typically has an epoxy resin, an epoxy resin curing agent, and an organic filler (swelling organic filler). The composition, the composition of the second aspect in which a curing accelerator is further blended with the composition of the first aspect, the composition of the third aspect in which an inorganic filler is further blended with the composition of the second aspect, or The composition according to the fourth aspect, in which a thermoplastic resin is further blended with the composition according to the third aspect. The composition according to the first to fourth aspects further includes a flame retardant, a thermosetting resin (an epoxy resin). Except for the above), organometallic compounds, various resin additives, and the like. In addition, in the varnish which consists of a composition of any aspect, an organic solvent may be mix | blended separately from the organic solvent contained in a swelling organic filler in the preparation stage.

[Adhesive film]
The adhesive film of the present invention is a resin composition layer obtained by applying the resin varnish on a support, and drying and removing the organic solvent by heating or blowing hot air, etc., by methods known to those skilled in the art. Can be produced.

  The drying conditions are not particularly limited, but the drying is performed so that the content of the organic solvent in the resin composition layer is 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. As drying conditions, suitable drying conditions can be appropriately set by simple experiments. Depending on the amount of organic solvent in the resin varnish, it is preferable to dry the resin varnish containing 30 to 60% by mass of the organic solvent at 50 to 150 ° C. for 3 to 10 minutes, and dry at 60 to 140 ° C. for 3 to 10 minutes. More preferably, drying at 70 to 130 ° C. for 3 to 10 minutes is further preferable, and drying at 80 to 120 ° C. for 3 to 10 minutes is even more preferable.

  The thickness of the resin composition layer formed in the adhesive film is preferably equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm, more preferably 20 to 80 μm, and more preferably 30 to 60 μm. Further preferred. The resin composition layer may be protected by a protective film described later. By protecting with a protective film, it is possible to prevent dust and the like from being attached to the surface of the resin composition layer and scratches.

  Examples of the support include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride; polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as “PET”), polybutylene terephthalate, and polyethylene naphthalate; polycarbonates; plastic films such as polyimide. Is mentioned. Among the plastic films, PET is particularly preferable. A metal foil such as a copper foil or an aluminum foil can be used as a support, and an adhesive film with a metal foil can be obtained. The protective film is preferably a similar plastic film. Further, the support and the protective film may be subjected to release treatment in addition to mat treatment and corona treatment. For example, a release treatment using a release agent such as a silicone resin release agent, an alkyd resin release agent, or a fluororesin release agent may be performed.

  Although the thickness of a support body is not specifically limited, 10-150 micrometers is preferable and 25-50 micrometers is more preferable. The thickness of the protective film is not particularly limited, but is preferably 1 to 40 μm, and more preferably 10 to 30 μm.

  The support is peeled off after being laminated on an inner layer circuit board or the like, or after forming an insulating layer by heat curing. If the support is peeled after the adhesive film is heat-cured, adhesion of dust and the like in the curing step can be prevented, and the surface smoothness of the insulating layer after curing can be improved. When peeling after curing, the support is preferably subjected to a release treatment in advance. In addition, it is preferable to form the resin composition layer formed on a support body so that the area of this layer may become smaller than the area of a support body. The adhesive film can be wound up in a roll shape and stored and stored.

[Multilayer printed wiring board using adhesive film]
Next, a method for producing a circuit board such as a multilayer printed wiring board using the adhesive film of the present invention will be described. When the resin composition layer is protected with a protective film, the resin composition layer is peeled off and then laminated on one or both sides of the inner circuit board so that the resin composition layer is in direct contact with the inner circuit board. In the adhesive film of the present invention, a method of heating and pressurizing by a vacuum laminating method and laminating on an inner layer circuit board under a reduced pressure is suitably used. The laminating method may be a batch method or a continuous method using a roll. Further, the adhesive film and the inner layer circuit board may be heated (preheated) as necessary before lamination.

  The inner layer circuit board mainly includes a conductive layer (circuit) patterned on one or both sides of a glass epoxy, metal substrate, polyester substrate, polyimide substrate, BT resin substrate, thermosetting polyphenylene ether substrate or the like. Say something. In addition, when manufacturing a multilayer printed wiring board in which conductor layers and insulating layers are alternately formed and a conductor layer (circuit) is patterned on one or both sides, an insulating layer and a conductor layer are further formed. The intermediate product to be included is also included in the inner layer circuit board in the present invention. In the inner layer circuit board, the surface of the conductor circuit layer is preferably roughened by a blackening process or the like from the viewpoint of adhesion of the insulating layer to the inner layer circuit board.

The laminating conditions are preferably a pressure bonding temperature (laminating temperature) of 70 to 140 ° C. and a pressure bonding pressure of preferably 1 to 11 kgf / cm ² (9.8 × 10 ^{4 to} 107.9 × 10 ⁴ N / m ² ). Lamination is preferably performed under a reduced pressure of 20 mmHg (26.7 hPa) or less. The vacuum lamination can be performed using a commercially available vacuum laminator. Commercially available vacuum laminators include, for example, a vacuum applicator manufactured by Nichigo-Morton Co., Ltd., a vacuum pressurizing laminator manufactured by Meiki Seisakusho, a roll dry coater manufactured by Hitachi Industries, Ltd., and Hitachi AIC Co., Ltd. ) Manufactured vacuum laminator and the like. After laminating the adhesive film on the inner layer circuit board in this way, when the support is peeled off, it can be peeled off and thermally cured to form an insulating layer on the inner layer circuit board. The thermosetting temperature is preferably in the range of 150 ° C to 220 ° C, more preferably in the range of 160 ° C to 200 ° C, and still more preferably in the range of 170 ° C to 190 ° C. The thermosetting time is preferably in the range of 20 to 180 minutes, more preferably in the range of 30 to 150 minutes, and still more preferably in the range of 60 to 120 minutes. Further, in order to make the surface roughness (Ra value) of the insulating layer finer, preliminary curing can be performed at 90 to 110 ° C. for 20 to 60 minutes before thermosetting.

Moreover, the lamination process which heats and pressurizes under reduced pressure can also be performed using a general vacuum hot press machine. For example, it can be performed by pressing a metal plate such as a heated SUS plate from the support layer side. As for the pressing conditions, the degree of vacuum is preferably 1 × 10 ⁻² MPa or less, and preferably 1 × 10 ⁻³ MPa or less. Although heating and pressurization can be carried out in one stage, it is preferable to carry out the conditions separately in two or more stages from the viewpoint of controlling the oozing of the resin. For example, the first stage press has a temperature of 70 to 150 ° C. and the pressure is in a range of 1 to 15 kgf / cm ² , and the second stage press has a temperature of 150 to 200 ° C. and a pressure of 1 to 40 kgf / cm ² It is preferable to carry out within a range. The time for each stage is preferably 30 to 120 minutes. Examples of commercially available vacuum hot press machines include MNPC-V-750-5-200 (manufactured by Meiki Seisakusho), VH1-1603 (manufactured by Kitagawa Seiki Co., Ltd.), and the like.

  After forming the insulating layer, if the support is not peeled before curing, it is peeled off at this stage. Next, holes are formed in the insulating layer formed on the inner circuit board to form via holes and through holes. Drilling can be performed, for example, by a known method such as drilling, laser, or plasma, or a combination of these methods, if necessary. However, drilling with a laser such as a carbon dioxide laser or YAG laser is the most common method. is there.

  Next, a roughening process is performed on the surface of the insulating layer. The roughening treatment is preferably performed by a wet roughening method using an oxidizing agent. Examples of the oxidizing agent include permanganate (potassium permanganate, sodium permanganate, etc.), dichromate, ozone, hydrogen peroxide / sulfuric acid, nitric acid and the like. Preferably, an alkaline permanganate solution (eg, potassium permanganate, sodium hydroxide solution of sodium permanganate), which is an oxidizer widely used for roughening an insulating layer in the production of multilayer printed wiring boards by a built-up method. It is preferable to perform roughening using.

  When the insulating layer is formed using the resin varnish of the present invention and the surface of the insulating layer is roughened, a dense rough surface with low roughness is formed, and the rough surface has a surface roughness (Ra A conductor layer having a high peel strength can be formed despite the low value. Therefore, a circuit board having wiring with high density and excellent adhesion can be manufactured.

The surface roughness (Ra value) of the surface of the insulating layer after roughening the surface of the insulating layer is preferably 300 nm or less, more preferably 280 nm or less, further preferably 260 nm or less, from the viewpoint that fine wiring can be formed. 240 nm or less is still more preferred, 230 nm or less is particularly preferred, 220 nm or less is particularly preferred, and 210 nm or less is particularly preferred. Further, from the viewpoint of ensuring the adhesion of fine wiring, 50 nm or more is preferable, 70 nm or more is more preferable, and 90 nm or more is more preferable. Ra value is a kind of numerical value representing surface roughness, and arithmetic This is called average roughness. Specifically, the absolute value of the height changing in the measurement region is measured from the surface as an average line, and is arithmetically averaged. For example, using WYKO NT3300 manufactured by Becoin Instruments, VSI contact mode,
It can be obtained from a numerical value obtained with a measurement range of 121 μm × 92 μm by a 50 × lens.

  Next, a conductor layer is formed by a method combining electroless plating and electrolytic plating on the surface of the insulating layer on which uneven anchors are formed by roughening treatment. Alternatively, a plating resist having a pattern opposite to that of the conductor layer can be formed, and the conductor layer can be formed only by electroless plating. After forming the conductor layer, the peel strength of the conductor layer is further improved and stabilized by annealing at 150 to 200 ° C. for 20 to 90 minutes, more preferably at 150 to 180 ° C. for 20 to 60 minutes. Can do. The peel strength of the insulating layer with respect to the conductor layer is preferably 0.53 kgf / cm or more, more preferably 0.55 kgf / cm or more, still more preferably 0.57 kgf / cm or more, from the viewpoint of obtaining sufficient adhesion. 59 kgf / cm or more is even more preferable. From the viewpoint of practicality, it is preferably 5 kgf / cm or less, more preferably 3 kgf / cm or less, still more preferably 1 kgf / cm or less.

  Moreover, as a method of patterning the conductor layer to form a circuit, for example, a subtractive method or a semi-additive method known to those skilled in the art can be used.

[Prepreg]
The prepreg of the present invention can be produced by impregnating the resin varnish of the present invention into a sheet-like fiber substrate made of fibers by a hot melt method or a solvent method and semi-curing by heating. That is, a resin varnish can be impregnated into a sheet-like fiber base material to obtain a prepreg.

  As a sheet-like fiber base material which consists of fibers, the 1 type (s) or 2 or more types selected from glass fiber, an organic fiber, a glass nonwoven fabric, and an organic nonwoven fabric can be used, for example. Among these, from the viewpoint of reducing the linear thermal expansion coefficient of the prepreg, sheet-like fiber base materials such as glass fiber, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric are preferable, glass fiber is more preferable, glass cloth, T glass fiber, and Q glass. Fiber is more preferred, and Q glass fiber is even more preferred.

  In the hot melt method, without dissolving the resin in an organic solvent, the melted resin is coated on a coated paper having good releasability from the resin and laminated to a sheet-like fiber substrate, or by a die coater. This is a method for producing a prepreg by direct coating or the like. Similarly to the adhesive film, the solvent method is a method in which a sheet-like fiber base material is immersed in a resin varnish obtained by dissolving a resin in an organic solvent, the resin varnish is impregnated into the sheet-like fiber base material, and then dried.

[Metal-clad laminate and multilayer printed wiring board using prepreg]
Next, a method for producing the metal-clad laminate and multilayer printed wiring board of the present invention using the prepreg of the present invention will be described. First, one or several prepregs are stacked, a metal plate is sandwiched through a release film, and press laminated under pressure and heating conditions to form a metal-clad laminate. Alternatively, one or several prepregs are stacked on the inner circuit board, a metal plate is sandwiched through a release film, and press lamination is performed under pressure and heating conditions to form a multilayer printed wiring board. The pressure is preferably 5 to 40 kgf / cm ² (49 × 10 ^{4 to} 392 × 10 ⁴ N / m ² ), and the temperature is preferably 120 to 200 ° C. for 20 to 100 minutes. Moreover, it can be manufactured by laminating by a vacuum laminating method and then heat-curing in the same manner as the adhesive film. After that, after the surface of the cured prepreg is roughened using an oxidizing agent, as in the above-described method, a conductor layer is formed by plating, whereby a circuit board such as a multilayer printed wiring board can be manufactured.

[Semiconductor device]
Furthermore, the semiconductor device of the present invention can be manufactured by using the multilayer printed wiring board of the present invention. A semiconductor device is manufactured by bonding a semiconductor element to the connection electrode portion on the multilayer printed wiring board. The mounting method of the semiconductor element is not particularly limited, and examples thereof include wire bonding mounting, flip chip mounting, mounting with an anisotropic conductive film (ACF), mounting with a non-conductive film (NCF), and the like.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated in detail, these do not restrict | limit this invention in any meaning. In the following description, “part” means “part by mass”.

<Measurement method / Evaluation method>
Various measurement methods and evaluation methods will be described.

<Preparation of adhesive film>
The resin varnishes obtained in Examples 1 to 3 and Comparative Examples 1, 2, 4, and 5 were formed on a polyethylene terephthalate (thickness 38 μm, hereinafter referred to as PET as needed) film, and the resin thickness after drying was 40 μm. It apply | coated with the die-coater so that it might become, and it was made to dry at 80-120 degreeC (average 110 degreeC) for 10 minutes, and the sheet-like adhesive film was obtained. Moreover, it apply | coated with the die-coater so that resin thickness after drying might be 10 micrometers, and it was made to dry at 80-110 degreeC (average 100 degreeC) for 4 minutes, and obtained the sheet-like adhesive film.

<Adjustment of sample for measuring peel strength and surface roughness (Ra value)>
(1) Substrate treatment of laminated board Both sides of a glass cloth base epoxy resin double-sided copper-clad laminated board (copper foil thickness 18 μm, substrate thickness 0.8 mm, Panasonic Electric Works Co., Ltd. R5715ES) are made by MEC CZ8100 The copper surface was roughened by dipping in (copper microetching agent, 2 μm etching).

(2) Lamination of adhesive film Using a batch type vacuum pressure laminator (MVLP-500 manufactured by Meiki Co., Ltd.), a 40 μm thick adhesive film prepared from the resin varnishes obtained in Examples and Comparative Examples was used. Lamination was performed on both sides of a double-sided copper-clad laminate. Lamination was performed by reducing the pressure for 30 seconds to a pressure of 13 hPa (hectopascal) or less, and then pressing at a set temperature of 100 ° C. for 30 seconds at a pressure of 0.74 MPa (megapascal).

(3) Curing of resin The PET film was peeled from the laminated adhesive film, and the resin was cured under curing conditions of 100 ° C. for 30 minutes and further at 180 ° C. for 30 minutes. Thereby, the insulating layer which consists of an insulating material hardened | cured on both surfaces of the double-sided copper clad laminated board was formed.

(4) Roughening treatment of insulating layer surface The laminated plate on which the insulating layer is formed is immersed in a swelling liquid, Swelling Dip Securiganth P (Swelling Dip Securiganth P) for 10 minutes at 60 ° C. Then, as a roughening solution, it was immersed in an Atotech Japan Co., Ltd. Concentrate Compact P (KMnO ₄ : 60 g / L, NaOH: 40 g / L aqueous solution) at 80 ° C. for 20 minutes. It was immersed for 5 minutes at 40 ° C. in the reduction solution securigant P of Japan Co., Ltd. By this series of steps, the surface of the insulating layer was roughened. The laminate after the roughening treatment was designated as Sample 1.

(5) Plating by semi-additive method The laminate was immersed in an electroless plating solution containing PdCl ₂ and then immersed in an electroless copper plating solution. After annealing at 150 ° C. for 30 minutes, electrolytic copper plating was performed to form a 30 μm thick conductor layer, and annealing was performed at 180 ° C. for 60 minutes. This laminate was designated as Sample 2.

<Measurement and evaluation of surface roughness (Ra value) after roughening treatment>
Sample 1 was measured using a non-contact type surface roughness meter (WYKO NT3300 manufactured by BEIKO INSTRUMENTS Co., Ltd.) in a VSI contact mode with a 50 × lens and a measurement range of 121 μm × 92
Ra value was calculated | required by the numerical value obtained as micrometer. And it measured by calculating | requiring the average value of the measurement point chosen at random.

<Measurement method of peel strength (peel strength) of plated copper layer>
The conductor layer of sample 2 has a 10 mm wide and 100 mm long cut using a cutter, and this end is peeled off to grasp the grip (TSE, Inc., Autocom type testing machine AC-50C-SL) The load (kgf / cm) when 35 mm was peeled off in the vertical direction at a speed of 50 mm / min was measured at room temperature in accordance with JIS C6481.

<Insulation reliability evaluation method>
Using a 10 μm thick adhesive film, electrolytic copper plating was performed in the same manner as described above to form a conductor layer with a thickness of 30 μm. A 10 cm diameter circular conductor pattern is formed on the conductor plating side, the circular conductor side is the positive electrode, and the copper foil side of the glass cloth base epoxy resin double-sided copper-clad laminate is the negative electrode. Insulation resistance values before and after 130 hours at 130 ° C., 85% humidity, 3.3 V DC application, 100 hours using an electrochemical migration tester (ECM-100 manufactured by J-RAS Co., Ltd.) It was measured.

<Example 1>
5 parts of an organic filler (IM-401, manufactured by Ganz Kasei Co., Ltd.), which is a core-shell particle made of polybutadiene, the shell layer is partially cross-linked polymethylmethacrylate with divinylbenzene, and 20 parts of solvent naphtha. It was allowed to stand at 40 ° C. for 2 hours. The organic filler absorbed the entire amount of solvent naphtha. Silica slurry (composition ratio, silica / MEK / silane coupling agent (N) manufactured by Admatechs Co., Ltd., spherical silica having an average particle diameter of 0.5 μm) is used as the organic filler in which the solvent naphtha is absorbed. -Phenyl-γ-aminopropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.)) = 70 parts / 30 parts / 0.5 parts) and naphthylene ether type epoxy resin (epoxy equivalent 277, DIC Corporation) ) "EXA-7311") 10 parts, liquid naphthalene type epoxy resin (epoxy equivalent 144, "DIC4032SS" manufactured by DIC Corporation), and crystalline bifunctional epoxy resin (Japan Epoxy Resin Corporation " YX4000HK ”, epoxy equivalent of about 185), 5 parts, and TK Hibis Disper Mix (Primix Co., Ltd. 3D- At 0 type) planetary wings, each component is sufficiently mixed at 65 ° C., was stirred while visually observed to be dissolved. The time was 1 hour.

  After cooling to room temperature, 16 parts of a prepolymer of bisphenol A dicyanate ("BA230S75" manufactured by Lonza Japan Co., Ltd., MEK solution having a cyanate equivalent of about 232 and a non-volatile component of 75% by mass), a phenol novolac type polyfunctional cyanate ester 6 parts of resin (Lonza Japan Co., Ltd. “PT30”, cyanate equivalent of about 124, MEK solution with 80% by mass of non-volatile components), active ester curing agent (DIC Corporation “HPC8000-65T”, active group equivalent of about 223 12 parts of a non-volatile component in a toluene solution of 65% by mass), and as a flame retardant (“HCA-HQ” manufactured by Sanko Co., Ltd., 10- (2,5-dihydroxyphenyl) -10-hydro-9-oxa-10- Add 5 parts of phosphaphenanthrene-10-oxide (average particle size 2 μm), and make sure that the components are mixed well. It was allowed to stir at room temperature. The time was 30 minutes.

  To the resulting mixture, T.P. K. High-speed dispersion treatment was performed at 5000 rpm for 30 minutes with a Hibis Disper mix homogenizer, and 2 parts of a 1% by weight MEK solution of 4-dimethylaminopyridine as a curing accelerator, cobalt (III) acetylacetonate (Tokyo Kasei Co., Ltd.) 1 part by weight of MEK solution (4.5 parts) and high-speed dispersion treatment for 30 minutes, followed by filtration with a filter having a filtration accuracy of 10 μm (SHP100 manufactured by ROKI Co., Ltd.) 15 MPa), a resin varnish was obtained.

<Example 2>
5 parts of organic filler (IM-401) was allowed to stand at room temperature for 8 hours in 20 parts of solvent naphtha. The organic filler absorbed the entire amount of solvent naphtha. Next, 10 parts of a naphthylene ether type epoxy resin, 10 parts of a liquid naphthalene type epoxy resin, and 5 parts of a crystalline bifunctional epoxy resin are added to 200 parts of the same silica slurry as in Example 1, and a planetary mixer ( The product was dissolved with stirring and heating at 65 ° C. for 1 hour using Inoue Seisakusho Co., Ltd .: PLM-100 type, and then cooled to room temperature. There, 16 parts of prepolymer solution of bisphenol A dicyanate, 6 parts of phenol novolac type polyfunctional cyanate ester resin solution, 12 parts of active ester curing agent solution, and organic filler (IM-401) in the above solvent naphtha for 8 hours The stationary one was added as it was, 5 parts of (HCA-HQ) was added as a flame retardant, and the mixture was stirred at room temperature while visually observing each component to be sufficiently mixed. The time was 1 hour.
The obtained suspension is pumped to a high-pressure homogenizer (NS3006H type manufactured by Niro Soabi Co., Ltd.) and continuously dispersed at a treatment pressure of 30 MPa. Finally, the dispersion is treated as a curing accelerator. Add 2 parts of a 1% by weight MEK solution of 4-dimethylaminopyridine and 4.5 parts of a 1% by weight MEK solution of cobalt (III) acetylacetonate (manufactured by Tokyo Chemical Industry Co., Ltd.), and add 30 parts with a planetary mixer. After stirring and mixing for a minute, the mixture was filtered through a filter having a filtration accuracy of 10 μm (SHP100 manufactured by ROKI Corporation) (differential pressure 0.15 MPa) to obtain a resin varnish.

<Example 3>
A resin varnish was obtained by performing filtration in the same manner as in Example 1 except that the filter having a filtration accuracy of 10 μm was changed to a filter having a filtration accuracy of 5 μm (SHP050 manufactured by ROKI Co., Ltd.).

<Comparative Example 1>
The mixture was heated and stirred in the same manner as in Example 1 except that 5 parts of the organic filler was not allowed to stand in 20 parts of the solvent naphtha, and 5 parts of the organic filler and 20 parts of the solvent naphtha were separately added to the silica slurry. . Even after stirring for 1 hour, the organic filler agglomerated vigorously, and even when heated and stirred for 2 hours, no improvement was observed. After that, high-speed dispersion treatment was carried out in exactly the same manner as in Example 1. However, since there were aggregates that could be visually confirmed in 30 minutes, the treatment time of high-speed dispersion was extended for 30 minutes, and the resulting dispersion treatment liquid was accelerated. As an agent, 2 parts of a 1% by weight MEK solution of 4-dimethylaminopyridine and 4.5 parts of a 1% by weight MEK solution of cobalt (III) acetylacetonate were added, and after stirring for 30 minutes, the filtration accuracy was 10 μm. The resin varnish was obtained by filtering with a filter (SHP100 manufactured by ROKI Co., Ltd.).

<Comparative example 2>
As in Example 2, 10 parts of naphthylene ether type epoxy resin, 10 parts of liquid naphthalene type epoxy resin, and 5 parts of crystalline bifunctional epoxy resin are added to 200 parts of silica slurry, and 65 ° C. using a planetary mixer. The mixture was stirred for 1 hour and then cooled. Separately, 16 parts of a prepolymer solution of bisphenol A dicyanate, 6 parts of a phenol novolac type polyfunctional cyanate ester resin solution, 12 parts of an active ester curing agent solution, and 20 parts of solvent naphtha are stirred and homogenized at room temperature with an organic filler. (Gantz Kasei Co., Ltd. IM-401) 5 parts was added and allowed to stand at room temperature for 8 hours. The mixture containing the organic filler was added to the silica / epoxy resin mixture, 5 parts of (HCA-HQ) was added as a flame retardant, and the mixture was stirred at room temperature while visually observing each component sufficiently mixed. . The stirring time required 4 hours. The obtained liquid mixture was pumped to a high-pressure homogenizer in the same manner as in Example 2 and continuously dispersed at a treatment pressure of 30 MPa. Finally, 4-dimethylaminopyridine was used as a curing accelerator in the dispersion treatment liquid. 2 parts of a 1% by weight MEK solution and 4.5 parts of a 1% by weight MEK solution of cobalt (III) acetylacetonate were added and mixed with a planetary mixer for 30 minutes, followed by filtration with a filter having a filtration accuracy of 10 μm. Thus, a resin varnish was obtained.

<Comparative Example 3>
Except for changing the filter with a filtration accuracy of 10 μm to a filter with a filtration accuracy of 5 μm (SHP050 manufactured by ROKI Co., Ltd.), an attempt was made to obtain a resin varnish exactly as in Comparative Example 1, but the pressure resistance of the filter immediately after the filtration The limit (0.49 MPa) was reached, the filter was clogged, and a resin varnish could not be obtained.

<Comparative example 4>
5 parts of organic filler (IM-401) was allowed to stand at 40 ° C. for 2 hours in 15 parts of solvent naphtha. The organic filler absorbed the entire amount of solvent naphtha. That is, 3 times the amount of solvent naphtha was absorbed by the organic filler. A resin varnish was obtained in exactly the same manner as in Example 1 except that an organic filler in which this solvent naphtha was absorbed was used.

  The results are shown in Table 1.

  As is apparent from the results in Table 1, the adhesive film obtained from the resin varnish produced by the method of the present invention forms a uniform and dense insulating layer with a rough surface, and has a high plating peel strength. I understood. On the other hand, in Comparative Example 1, a resin varnish produced without performing an organic solvent absorption treatment (swelling treatment) on an organic filler is used, and in Comparative Example 2, an organic resin is dissolved in a resin solution obtained by dissolving a resin in a solvent. Resin varnish produced through the process of allowing the filler to stand and allowing the organic filler to absorb the solvent is used. In both cases, the production time is long, and it takes time and effort from the obtained adhesive film. It can be seen that unevenness is observed on the rough surface of the formed insulating layer, the roughness value is large, and the plating peel strength is low. In Comparative Example 4, the amount of organic solvent absorbed into the organic filler was insufficient, the rough surface of the insulating layer formed from the obtained adhesive film was uneven, the roughness value was large, and the plating peel It turns out that intensity will become low. Furthermore, in the insulation reliability, when Example 1 and Comparative Example 1 are compared, it can be seen that the insulation reliability is also improved by improving the dispersibility according to the present invention. It can also be seen that the insulation reliability of the insulating layer formed from the resin varnish filtered through the filter of Example 3 having a filtration accuracy of 5 μm is further improved.

  According to the present invention, by applying a specific swelling process to the organic filler, the organic filler is contained, but the organic filler is high so as to provide low roughness, high peel and high insulation reliability after curing. A process for producing a resin varnish having dispersibility can be provided. Furthermore, adhesive films, prepregs, metal-clad laminates, circuit boards, multilayer printed wiring boards, semiconductor devices, computers, mobile phones, digital cameras, televisions, motorcycles, automobiles, trains, ships, aircraft, etc. using the resin varnish Also became available.

Claims (17)

A method for producing a resin varnish containing an organic filler,
The manufacturing method of the resin varnish characterized by having the following process 1)-process 3).
Step 1) A step of swelling the organic filler with an organic solvent of 3.5 to 8 times the organic filler (swelling step).
Step 2) A step (mixing step) of adding and mixing the varnish raw material (excluding the organic filler) to the swollen organic filler produced by the swelling step.
Step 3) A step of dispersing the swelling organic filler in the mixed liquid produced by the mixing step (dispersing step). Furthermore, it has the following process 4), The manufacturing method of the resin varnish of Claim 1 characterized by the above-mentioned.
Step 4) A step of filtering the dispersion treatment liquid produced by the dispersion step (filtration step)   The amount of the organic filler used in step 1) is 0.1% by mass or more and 10% by mass or less when the nonvolatile component of the resin varnish is 100% by mass. The manufacturing method of the resin varnish of description.   The process for producing a resin varnish according to any one of claims 1 to 3, wherein the swelling organic filler is dispersed using a homogenizer in step 3). The process for producing a resin varnish according to any one of claims 2 to 4, wherein a filter having a filtration accuracy of 10 µm or less is used in step 4).   The method for producing a resin varnish according to claim 5, wherein the collection rate of the filter with respect to the aggregate of 2 µm is 80% or more, and the collection rate with respect to the aggregate of 3 µm is 85% or more.   The process for producing a resin varnish according to any one of claims 2 to 6, wherein in step 4), the filtration pressure is 0.4 MPa or less.   8. The method for producing a resin varnish according to claim 7, wherein in step 4), the filtration pressure is 0.03 MPa or more.   The method for producing a resin varnish according to any one of claims 1 to 8, wherein step 1) is performed under low flow.   The method for producing a resin varnish according to any one of claims 1 to 9, wherein the organic solvent in step 1) is an aromatic hydrocarbon solvent. The manufacturing method of the resin varnish of any one of Claims 1-10 which is a manufacturing method of the resin varnish for the insulating layers of a circuit board. Claim 1 of a resin varnish obtained in 10 The method according to any one of method of the adhesive film. Claim 1 of a resin varnish obtained in 10 The method according to any one of method of manufacturing a prepreg. Claim 1 of a resin varnish obtained in 10 The method according to any one of method for producing a metal-clad laminate. Claim 1 of a resin varnish obtained in 10 The method according to any one of method of manufacturing a multilayer printed wiring board.   The surface roughness (Ra value) of the surface of the insulating layer is 50 nm or more and 300 nm or less using the resin varnish obtained by the method according to any one of claims 1 to 11, and the conductor of the insulating layer A method for producing a multilayer printed wiring board having a peel strength of 0.53 kgf / cm to 5 kgf / cm. Characterized by using the multilayer printed wiring board obtained by the method of claim 15 or 16, a method of manufacturing a semiconductor device.