JP2014208747A - Resin composition, resin film, and multilayer substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition from which a resin film excellent in storage stability can be obtained.SOLUTION: The resin composition according to the present invention is used by being molded into a film shape to obtain a resin film. The resin composition contains an epoxy resin, a cyanate ester compound, a phenoxy resin, and a curing accelerator. The ratio of the number of epoxy groups of the epoxy resin in the resin composition to the total number of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in the resin composition is 10 to 30 inclusive.

Description

  The present invention relates to a resin composition used for obtaining a resin film by molding into a film shape. The present invention also relates to a resin film and a multilayer substrate using the resin composition.

  Conventionally, various resin compositions have been used to obtain electronic components such as laminates and printed wiring boards. For example, in a multilayer printed wiring board, a resin composition is used in order to form an insulating layer for insulating inner layers or to form an insulating layer located in a surface layer portion. Wiring, which is generally a metal layer, is laminated on the surface of the insulating layer.

  As an example of the above resin composition, Patent Document 1 below discloses a resin composition containing a cyanate ester resin, an anthracene epoxy resin, and a thermoplastic resin. Patent Document 1 describes that an organic insulating layer having a low coefficient of thermal expansion and easy smear removal can be provided.

  Patent Document 2 below discloses a resin composition containing a cyanate resin, a phenol resin, and an inorganic filler. Here, it is described that the resin composition has high flame retardancy and heat resistance and a low coefficient of linear expansion. Furthermore, Patent Document 1 describes that it is preferable to use an epoxy resin in order to improve the reactivity of the cyanate resin.

  Patent Document 3 below discloses a resin composition containing a compound having a heterocyclic group, an epoxy resin, and a cyanate compound. A filler can be added to this resin composition. Here, it is described that a cured product having low water absorption, excellent dielectric properties, and high heat resistance and dimensional stability can be obtained.

JP 2007-291369 A JP 2003-096296 A JP 2006-028498 A

  Although the resin composition described in Patent Documents 1 to 3 is not necessarily used to obtain a resin film by forming into a film shape, the resin film described in Patent Documents 1 to 3 is formed into a film shape as a resin When a film is obtained, there is a problem that the storage stability of the obtained resin film is lowered.

  The resin composition is often mixed with an inorganic filler for the purpose of lowering the coefficient of thermal expansion. In recent years, along with miniaturization and high performance of electronic devices, the electronic components are also required to have finer wiring and further reduced thermal expansion coefficient in the insulating layer. In order to meet such demands, a large amount of inorganic filler may be blended in the resin composition for forming the insulating layer.

  On the other hand, conventionally, in order to obtain a cured product having a low coefficient of thermal expansion, a conventional resin film containing an inorganic filler has a problem that it is difficult to sufficiently improve the storage stability.

  The objective of this invention is providing the resin composition which can obtain the resin film excellent in storage stability, and the resin film and multilayer substrate using this resin composition.

  A limited object of the present invention is to include an inorganic filler, so that the coefficient of thermal expansion of the cured product is low, and the adhesion between the cured product and the metal layer can be further improved, and the resin composition And providing a resin film and a multilayer substrate using the resin composition.

  According to a wide aspect of the present invention, a resin composition used for forming a resin film by molding into a film, comprising an epoxy resin, a cyanate ester compound, a phenoxy resin, and a curing accelerator, The ratio of the number of epoxy groups of the epoxy resin in the resin composition to the total number of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in the resin composition is 10 or more and 30 or less. Provided.

  On the specific situation with the resin composition which concerns on this invention, content of the said hardening accelerator is 0.01 weight% or more and 3.0 weight% or less in 100 weight% of total solid content contained in the said resin composition. It is.

  On the specific situation with the resin composition which concerns on this invention, content of the said cyanate ester compound is 20 to 100 weight part with respect to a total of 100 weight part of the said epoxy resin and the said phenoxy resin. .

  On the specific situation with the resin composition which concerns on this invention, the molecular weight of the said epoxy resin is 200-3000.

  On the specific situation with the resin composition which concerns on this invention, the weight average molecular weights of the said phenoxy resin are 5000 or more and 100,000 or less.

  In a specific aspect of the resin composition according to the present invention, the resin composition further includes an inorganic filler.

  On the specific situation with the resin composition which concerns on this invention, the said inorganic filler is a silica.

  On the specific situation with the resin composition which concerns on this invention, content of the said inorganic filler is 40 to 85 weight% in 100 weight% of total solid content contained in a resin composition.

  On the specific situation with the resin composition which concerns on this invention, this resin composition is used in order to obtain the hardened | cured material processed by a roughening process or a desmear process.

  According to the wide aspect of this invention, the resin film obtained by shape | molding the resin composition mentioned above in the film form is provided.

  According to a wide aspect of the present invention, there is provided a resin film comprising a circuit board and an insulating layer disposed on the circuit board, wherein the insulating layer is obtained by molding the above-described resin composition into a film shape. A multilayer substrate is provided that is formed using the method.

  The resin composition according to the present invention includes an epoxy resin, a cyanate ester compound, a phenoxy resin, and a curing accelerator, and further the epoxy in the resin composition having the number of epoxy groups of the epoxy resin in the resin composition. Since the ratio of the resin and the phenoxy resin to the total number of alcoholic hydroxyl groups is 10 or more and 30 or less, the resin composition according to the present invention is formed into a film shape, thereby being excellent in storage stability. Can be obtained.

FIG. 1 is a partially cutaway front sectional view schematically showing a multilayer substrate using a resin composition according to an embodiment of the present invention.

  Details of the present invention will be described below.

(Resin composition)
The resin composition according to the present invention is used for obtaining a resin film by molding into a film shape. The resin composition according to the present invention includes an epoxy resin, a cyanate ester compound, and a phenoxy resin. The ratio of the number of epoxy groups of the epoxy resin in the resin composition according to the present invention to the total number of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in the resin composition according to the present invention is 10 or more, 30 It is as follows.

  By adopting the above-described configuration in the resin composition according to the present invention, when the resin composition according to the present invention is molded into a film to obtain a resin film, the storage stability of the resulting resin film can be enhanced. . In the resin composition according to the present invention, the progress of the curing reaction during storage near room temperature (23 ° C.) can be suppressed.

  In the resin composition according to the present invention, for example, when the resin film after storage is bent, whitening and cracking hardly occur. Furthermore, when the resin film after storage is cut into a predetermined size with a cutter or the like, cracks or chips are less likely to occur. Furthermore, when the resin film after storage is laminated on a member (circuit board or the like) having concave portions or convex portions on the surface, excessive unevenness is hardly generated on the surface opposite to the member side of the resin film.

  In the resin composition according to the present invention, the progress of the curing reaction during storage near room temperature (23 ° C.) can be suppressed.

  The resin composition according to the present invention further includes a curing accelerator in addition to the epoxy resin, the cyanate ester compound, and the phenoxy resin. In the resin composition according to the present invention, the storage stability of the resin film can be enhanced despite containing a curing accelerator. In the resin composition of the present invention, despite containing a curing accelerator, cracking or chipping hardly occurs during cutting of the resin film after storage, and unevenness of the surface hardly occurs during lamination of the resin film after storage. Become.

  Moreover, in the resin composition or resin film containing the conventional cyanate ester compound, there exists a problem that a metal tends to act as a curing catalyst. For this reason, for example, when a resin film is cured on a substrate on which metal wiring is formed, there is a problem that the degree of curing after curing changes depending on the thickness of the resin film. When the degree of cure changes, the surface roughness of the roughened surface changes, and the adhesive strength between the cured product and the metal layer also changes.

  On the other hand, in the present invention, the resin film is hardly dependent on the thickness of the resin film when the resin film is cured on the member having the metal on the surface in spite of using the cyanate ester compound. The film can be uniformly cured. For example, even when resin films having different thicknesses are cured on a substrate with metal, the degree of cure of the cured product of the resin film can be made uniform. Whether the resin film is thick or thin, the degree of cure of the cured product of the resin film can be easily controlled within a predetermined range on a member having a metal on the surface. In the resin composition containing a cyanate ester compound, the present invention can cure the resin film uniformly without depending on the thickness of the resin film even if the resin film is cured in contact with a metal. There is one major feature that can be done.

  Ratio of the number of epoxy groups of the epoxy resin in the resin composition according to the present invention to the total number of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in the resin composition according to the present invention (number of epoxy groups) / Total number of alcoholic hydroxyl groups) is 10 or more and 30 or less. When the ratio (number of epoxy groups / total number of alcoholic hydroxyl groups) is less than the lower limit, the storage stability of the resin composition is deteriorated. When the ratio (number of epoxy groups / total number of alcoholic hydroxyl groups) exceeds the upper limit, the reactivity between the cyanate ester compound and the epoxy resin is deteriorated. The ratio (number of epoxy groups / total number of alcoholic hydroxyl groups) is preferably 15 or more, and preferably 25 or less.

  In the resin composition, the ratio (number of epoxy groups / total number of alcoholic hydroxyl groups) can be evaluated by dividing the reciprocal of the epoxy equivalent by the reciprocal of the alcoholic hydroxyl equivalent.

  The resin film obtained by molding the resin composition according to the present invention into a film is a curable resin film, and is a resin film before main curing. The resin film is preferably a B stage film. The B stage film can be used as a buildup film or the like.

  The resin composition according to the present invention preferably contains an inorganic filler. The resin composition according to the present invention does not contain or contain a solvent.

  Hereinafter, the detail of each component used for the resin composition which concerns on this invention is demonstrated.

[Epoxy resin]
The epoxy resin contained in the resin composition is not particularly limited. A conventionally well-known epoxy resin can be used as this epoxy resin. The epoxy resin refers to an organic compound having at least one epoxy group. As for an epoxy resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, biphenyl type epoxy resin, biphenyl novolac type epoxy resin, biphenol type epoxy resin, and naphthalene type epoxy resin. Fluorene type epoxy resin, phenol aralkyl type epoxy resin, naphthol aralkyl type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, epoxy resin having adamantane skeleton, epoxy resin having tricyclodecane skeleton, and triazine nucleus Examples thereof include an epoxy resin having a skeleton.

  The epoxy resin preferably has a biphenyl skeleton, and is preferably a biphenyl type epoxy resin. When the said epoxy resin has biphenyl frame | skeleton, the adhesive strength of hardened | cured material and a metal layer becomes still higher.

  From the viewpoint of further reducing the surface roughness of the roughened cured product and further increasing the adhesive strength between the cured product and the metal layer, the epoxy equivalent of the epoxy resin is preferably 90 or more, More preferably, it is 100 or more, preferably 1000 or less, more preferably 800 or less.

  From the viewpoint of obtaining a resin film that is more excellent in storage stability, the molecular weight of the epoxy resin is preferably 200 or more, more preferably 350 or more, preferably 3000 or less, more preferably 1000 or less.

  The molecular weight of the epoxy resin is more preferably 1000 or less. In this case, even if the content of the inorganic filler in the resin composition is 60% by weight or more, a resin composition having high fluidity can be obtained. For this reason, when the uncured product of the resin composition or the resin film is laminated on the substrate, the inorganic filler can be uniformly present.

  The molecular weight of the epoxy resin and the molecular weight of the cyanate ester compound described below can be obtained from the structural formula when the epoxy resin or cyanate ester compound is not a polymer and when the structural formula of the epoxy resin or cyanate ester compound can be specified. It means the molecular weight that can be calculated. Moreover, when the said epoxy resin or cyanate ester compound is a polymer, a weight average molecular weight is meant.

[Cyanate ester compounds]
The resin composition includes a curing agent in order to cure the epoxy resin.

  As the curing agent, cyanate ester compound (cyanate ester curing agent), phenol compound (phenol curing agent), amine compound (amine curing agent), thiol compound (thiol curing agent), imidazole compound, phosphine compound, acid anhydride, Examples include active ester compounds and dicyandiamide.

  In the present invention, a cyanate ester compound is used as the curing agent. When a cyanate ester compound is used as the curing agent, a cured product in which the dimensional change due to heat is further smaller than when other curing agents are used is obtained. In addition, when a cyanate ester compound is used as the curing agent, the surface roughness of the surface of the cured product is further reduced as compared with the case of using another curing agent, and the adhesive strength between the cured product and the metal layer is increased. The wiring becomes higher and finer wiring is formed on the surface of the cured product. Moreover, by using the cyanate ester compound, the handling property of the resin film containing a large amount of the inorganic filler is improved, and the glass transition temperature of the cured product is further increased.

  The cyanate ester compound is not particularly limited. A conventionally known cyanate ester compound can be used as the cyanate ester compound. As for the said cyanate ester compound, only 1 type may be used and 2 or more types may be used together.

  Examples of the cyanate ester compound include novolac-type cyanate ester compounds, bisphenol-type cyanate ester compounds, and prepolymers in which these are partially trimerized. As said novolak-type cyanate ester compound, a phenol novolak-type cyanate ester compound, an alkylphenol-type cyanate ester compound, etc. are mentioned. Examples of the bisphenol type cyanate ester compound include bisphenol A type cyanate ester compounds, bisphenol E type cyanate ester compounds, and tetramethylbisphenol F type cyanate ester compounds.

  Commercially available products of the above cyanate ester compounds include phenol novolac-type cyanate ester compounds (“Lonza Japan” “PT-30” and “PT-60”), and prepolymers (Lonza Japan) in which bisphenol-type cyanate ester compounds are trimerized. "BA-230S", "BA-3000S", "BTP-1000S", and "BTP-6020S") manufactured by the company.

  The molecular weight of the cyanate ester compound is preferably 3000 or less. In this case, the content of the inorganic filler in the resin composition can be increased. Even if the content of the inorganic filler is large, the resin composition having high fluidity and the resin film having high fluidity at the time of melting. Is obtained.

  The molecular weight of the cyanate ester compound is preferably 1000 or less. In this case, even if the content of the inorganic filler in the resin composition is 50% by weight or more, a resin composition having high fluidity and a resin film having high fluidity upon melting can be obtained.

  The surface roughness of the surface of the cured product is further reduced, the adhesive strength between the cured product and the metal layer is further increased, finer wiring is formed on the surface of the cured product, and good by the cyanate ester compound. From the viewpoint of imparting insulation reliability, the cyanate ester group equivalent of the cyanate ester compound is preferably 250 or less.

  The content of the cyanate ester compound with respect to 100 parts by weight of the total of the epoxy resin and the phenoxy resin is preferably 20 parts by weight or more, more preferably 30 parts by weight or more, preferably 100 parts by weight or less. Is 60 parts by weight or less. When the content of the cyanate ester compound is not less than the above lower limit and not more than the above upper limit, a resin film more excellent in storage stability can be obtained.

[Phenoxy resin]
By using the phenoxy resin, deterioration of the embedding property of the resin film with respect to the holes or irregularities of the circuit board and non-uniformity of the inorganic filler can be suppressed. In addition, since the melt viscosity can be adjusted by using a phenoxy resin, the dispersibility of the inorganic filler is improved, and the resin film is difficult to wet and spread in an unintended region during the curing process. The phenoxy resin contained in the resin composition is not particularly limited. A conventionally known phenoxy resin can be used as the phenoxy resin. As for the said phenoxy resin, only 1 type may be used and 2 or more types may be used together.

  Examples of the phenoxy resin include phenoxy resins having a skeleton such as a bisphenol A skeleton, a bisphenol F skeleton, a bisphenol S skeleton, a biphenyl skeleton, a novolac skeleton, a naphthalene skeleton, and an imide skeleton.

  Examples of commercially available phenoxy resins include “YP50”, “YP55” and “YP70” manufactured by Nippon Steel & Sumikin Chemical Co., Ltd., and “1256B40”, “4250”, “4256H40” manufactured by Mitsubishi Chemical Corporation, “ 4275 "," YX6954BH30 "," YX8100BH30 ", and the like.

  From the viewpoint of obtaining a resin film that is more excellent in storage stability, the weight average molecular weight of the phenoxy resin is preferably 5000 or more, more preferably 10,000 or more, preferably 100,000 or less, more preferably 50000 or less.

  The said weight average molecular weight of the said phenoxy resin shows the weight average molecular weight in polystyrene conversion measured by gel permeation chromatography (GPC).

  The content of the phenoxy resin is not particularly limited. In 100% by weight of the total solid content contained in the resin composition according to the present invention, the content of the phenoxy resin is preferably 2% by weight or more, more preferably 4% by weight or more, preferably 15% by weight or less, more preferably 10% by weight or less. When the content of the phenoxy resin is not less than the above lower limit and not more than the above upper limit, the embedding property of the resin film with respect to the holes or irregularities of the circuit board becomes good. When the content of the phenoxy resin is not less than the above lower limit, the resin composition can be more easily formed into a film, and a better insulating layer can be obtained. When the content of the phenoxy resin is not more than the above upper limit, the thermal expansion coefficient of the cured product is further reduced. The surface roughness of the surface of the cured product is further reduced, and the adhesive strength between the cured product and the metal layer is further increased.

[Inorganic filler]
The resin composition does not contain or contains an inorganic filler. The resin composition preferably contains an inorganic filler. Use of the inorganic filler further reduces the dimensional change due to heat of the cured product. Furthermore, the surface roughness of the surface of the cured product is further reduced, and the adhesive strength between the cured product and the metal layer is further increased.

  Examples of the inorganic filler include silica, talc, clay, mica, hydrotalcite, alumina, magnesium oxide, aluminum hydroxide, aluminum nitride, and boron nitride.

  The surface roughness of the cured product is reduced, the adhesive strength between the cured product and the metal layer is further increased, finer wiring is formed on the surface of the cured product, and better insulation reliability is achieved by the cured product. From the viewpoint of imparting the above, the inorganic filler is preferably silica or alumina, more preferably silica, and still more preferably fused silica. By using silica, the coefficient of thermal expansion of the cured product is further reduced, the surface roughness of the surface of the cured product is effectively reduced, and the adhesive strength between the cured product and the metal layer is effectively increased. The shape of silica is preferably substantially spherical.

  The average particle size of the inorganic filler is preferably 10 nm or more, more preferably 50 nm or more, further preferably 150 nm or more, preferably 20 μm or less, more preferably 10 μm or less, still more preferably 5 μm or less, and particularly preferably 1 μm or less. is there. When the average particle size of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the size of the holes formed by the roughening treatment or the like becomes fine, and the number of holes increases. As a result, the adhesive strength between the cured product and the metal layer is further increased.

  A median diameter (d50) value of 50% is employed as the average particle diameter of the inorganic filler. The average particle size can be measured using a laser diffraction / scattering particle size distribution measuring apparatus.

  Each of the inorganic fillers is preferably spherical, and more preferably spherical silica. In this case, the surface roughness of the surface of the cured product is effectively reduced, and the adhesive strength between the insulating layer and the metal layer is effectively increased. When each of the inorganic fillers is spherical, the aspect ratio of each of the inorganic fillers is preferably 2 or less, more preferably 1.5 or less.

  The inorganic filler is preferably surface-treated, and more preferably surface-treated with a silane coupling agent. Thereby, the surface roughness of the surface of the roughened cured product is further reduced, the adhesive strength between the cured product and the metal layer is further increased, and finer wiring is formed on the surface of the cured product, and more Better inter-wiring insulation reliability and interlayer insulation reliability can be imparted to the cured product.

  Examples of the coupling agent include silane coupling agents, titanate coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include methacryl silane, acrylic silane, amino silane, imidazole silane, vinyl silane, and epoxy silane.

  In the total solid content of 100% by weight contained in the resin composition, the content of the inorganic filler is preferably 25% by weight or more, more preferably 30% by weight or more, still more preferably 40% by weight or more, and particularly preferably 50%. % By weight or more, preferably 99% by weight or less, more preferably 85% by weight or less, still more preferably 80% by weight or less, and particularly preferably 75% by weight or less. When the total content of the inorganic filler is not less than the above lower limit and not more than the above upper limit, the surface roughness of the surface of the cured product is further reduced, and the adhesive strength between the cured product and the metal layer is further increased, In addition, finer wiring is formed on the surface of the cured product, and at the same time, with this amount of inorganic filler, it is possible to lower the thermal expansion coefficient of the cured product as well as metal copper.

[Curing accelerator]
The resin composition includes a curing accelerator. By using the curing accelerator, the curing rate is further increased. By rapidly curing the resin film, the crosslinked structure in the cured product becomes uniform, the number of unreacted functional groups decreases, and as a result, the crosslinking density increases. The said hardening accelerator is not specifically limited, A conventionally well-known hardening accelerator can be used. As for the said hardening accelerator, only 1 type may be used and 2 or more types may be used together.

  Examples of the curing accelerator include imidazole compounds, phosphorus compounds, amine compounds, and organometallic compounds.

  Examples of the imidazole compound include 2-undecylimidazole, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl- 2-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-un Decylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazolium trimellitate, 1-cyanoethyl-2-phenylimidazolium trimellitate, 2,4-diamino-6- [2 ′ -Methyl Midazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-undecylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6 [2′-Ethyl-4′-methylimidazolyl- (1 ′)]-ethyl-s-triazine, 2,4-diamino-6- [2′-methylimidazolyl- (1 ′)]-ethyl-s-triazine Isocyanuric acid adduct, 2-phenylimidazole isocyanuric acid adduct, 2-methylimidazole isocyanuric acid adduct, 2-phenyl-4,5-dihydroxymethylimidazole and 2-phenyl-4-methyl-5-dihydroxymethylimidazole Can be mentioned.

  Examples of the phosphorus compound include triphenylphosphine.

  Examples of the amine compound include diethylamine, triethylamine, diethylenetetramine, triethylenetetramine and 4,4-dimethylaminopyridine.

  Examples of the organometallic compound include zinc naphthenate, cobalt naphthenate, tin octylate, cobalt octylate, bisacetylacetonate cobalt (II), and trisacetylacetonate cobalt (III).

  The content of the curing accelerator is not particularly limited. In 100% by weight of the total solid content contained in the resin composition, the content of the curing accelerator is preferably 0.01% by weight or more, more preferably 0.9% by weight or more, preferably 3.0% by weight. % Or less, more preferably 1.8% by weight or less. When the content of the curing accelerator is not less than the above lower limit and not more than the above upper limit, the resin film is efficiently cured. If content of the said hardening accelerator is a more preferable range, the storage stability of a resin composition will become still higher and a much better hardened | cured material will be obtained.

[solvent]
The resin composition does not contain or contains a solvent. By using the solvent, the viscosity of the resin composition can be controlled within a suitable range, and the coatability of the resin composition can be improved. Moreover, the said solvent may be used in order to obtain the slurry containing the said inorganic filler. As for the said solvent, only 1 type may be used and 2 or more types may be used together.

  Examples of the solvent include acetone, methanol, ethanol, butanol, 2-propanol, 2-methoxyethanol, 2-ethoxyethanol, 1-methoxy-2-propanol, 2-acetoxy-1-methoxypropane, toluene, xylene, methyl ethyl ketone, Examples thereof include N, N-dimethylformamide, methyl isobutyl ketone, N-methyl-pyrrolidone, n-hexane, cyclohexane, cyclohexanone, and naphtha as a mixture.

  Most of the solvent is preferably removed when the resin composition is formed into a film. Therefore, the boiling point of the solvent is preferably 200 ° C. or lower, more preferably 180 ° C. or lower. The content of the solvent in the resin composition is not particularly limited. The content of the solvent can be appropriately changed in consideration of the coating property of the resin composition.

[Other ingredients]
For the purpose of improving impact resistance, heat resistance, resin compatibility, workability, etc., the resin composition includes a leveling agent, a flame retardant, a coupling agent, a colorant, an antioxidant, an ultraviolet degradation inhibitor, An antifoaming agent, a thickener, a thixotropic agent, a thermosetting resin other than the above-described epoxy resin, a thermoplastic resin other than the phenoxy resin, and the like may be added.

  Examples of the coupling agent include silane coupling agents, titanium coupling agents, and aluminum coupling agents. Examples of the silane coupling agent include vinyl silane, amino silane, imidazole silane, and epoxy silane.

  Examples of the other thermosetting resins include polyphenylene ether resins, divinyl benzyl ether resins, polyarylate resins, diallyl phthalate resins, polyimide resins, benzoxazine resins, benzoxazole resins, bismaleimide resins, and acrylate resins.

  As said other thermoplastic resin, a polyvinyl acetal resin, a rubber component, an organic filler, etc. are mentioned.

(Resin film)
The resin composition according to the present invention is obtained by molding the above-described resin composition into a film shape.

  In the present invention, even when a cyanate ester compound is used, when the resin film is cured on a member having a metal on the surface, the resin film is uniformly cured without depending on the thickness of the resin film. Can be made. On the other hand, from the viewpoint of more uniformly controlling the degree of cure of the resin film, the thickness of the resin film is preferably 5 μm or more, and preferably 200 μm or less. Moreover, it is preferable that the resin composition which concerns on this invention is used in order to obtain the resin film of said preferable thickness.

  As a method for forming the resin composition into a film, for example, an extrusion molding method is used in which the resin composition is melt-kneaded using an extruder, extruded, and then formed into a film using a T-die or a circular die. And a casting molding method in which a resin composition containing a solvent is cast to form a film, and other conventionally known film molding methods. Especially, since it can respond to thickness reduction, the extrusion molding method or the casting molding method is preferable. The film includes a sheet.

  The resin composition which is a B stage film can be obtained by forming the resin composition into a film and drying it by heating at 90 to 200 ° C. for 1 to 180 minutes, for example, so that curing by heat does not proceed excessively. .

  The film-like resin composition that can be obtained by the drying process as described above is referred to as a B-stage film. The B-stage film is a semi-cured product in a semi-cured state. The semi-cured product is not completely cured and curing can proceed further.

  The resin film may not be a prepreg. When the resin film is not a prepreg, migration does not occur along a glass cloth or the like. Further, when laminating or precuring the resin film, the surface is not uneven due to the glass cloth. Moreover, by setting it as the resin film which does not contain a prepreg, the dimensional change by the heat | fever of hardened | cured material becomes small, shape retention property becomes high, and a semiadditive process suitability becomes high.

  The said resin composition can be used suitably in order to form a laminated film provided with a base material and the resin film laminated | stacked on the one surface of this base material. The resin film in the laminated film is formed from the resin composition.

  Examples of the base material of the laminated film include polyester resin films such as polyethylene terephthalate film and polybutylene terephthalate film, olefin resin films such as polyethylene film and polypropylene film, polyimide resin film, metal foil such as copper foil and aluminum foil, and the like. Can be mentioned. The surface of the base material may be subjected to a release treatment as necessary.

  When the resin composition and the resin film are used as an insulating layer of a circuit, the thickness of the insulating layer formed of the resin composition or the resin film is equal to or greater than the thickness of the conductor layer (metal layer) forming the circuit. It is preferable that The thickness of the insulating layer is preferably 5 μm or more, and preferably 200 μm or less.

(Printed wiring board)
The resin composition and the resin film are suitably used for forming an insulating layer in a printed wiring board.

  The printed wiring board can be obtained, for example, by heat-pressing the resin film.

  A metal foil can be laminated on one side or both sides of the resin film. The method for laminating the resin film and the metal foil is not particularly limited, and a known method can be used. For example, the resin film can be laminated on the metal foil using an apparatus such as a parallel plate press or a roll laminator while applying pressure while heating or without heating.

(Copper-clad laminate and multilayer board)
The resin composition and the resin film are preferably used for obtaining a copper-clad laminate. An example of the copper-clad laminate is a copper-clad laminate including a copper foil and a resin film laminated on one surface of the copper foil. The resin film of this copper-clad laminate is formed from the resin composition.

  The thickness of the copper foil of the copper-clad laminate is not particularly limited. The thickness of the copper foil is preferably in the range of 1 to 50 μm. Moreover, in order to raise the adhesive strength of the insulating layer which hardened the said resin film, and copper foil, it is preferable that the said copper foil has a fine unevenness | corrugation on the surface. The method for forming the unevenness is not particularly limited. Examples of the method for forming the unevenness include a formation method by treatment using a known chemical solution.

  The resin composition and the resin film are preferably used for obtaining a multilayer substrate. As an example of the multilayer substrate, a multilayer substrate including a circuit substrate and an insulating layer stacked on the surface of the circuit substrate can be given. The insulating layer of the multilayer substrate is formed using a resin film obtained by forming the resin composition into a film. The insulating layer is preferably laminated on the surface of the circuit board on which the circuit is provided. Part of the insulating layer is preferably embedded between the circuits.

  In the multilayer substrate, it is preferable that the surface of the insulating layer opposite to the surface on which the circuit substrate is laminated is roughened.

  The roughening method can be any conventionally known roughening method and is not particularly limited. The surface of the insulating layer may be subjected to a swelling treatment before the roughening treatment.

  Moreover, it is preferable that the said multilayer substrate is further equipped with the copper plating layer laminated | stacked on the surface by which the roughening process of the said insulating layer was carried out.

  As another example of the multilayer board, the circuit board, the insulating layer laminated on the surface of the circuit board, and the surface of the insulating layer opposite to the surface on which the circuit board is laminated are laminated. And a multilayer substrate provided with copper foil. The insulating layer and the copper foil are formed by curing the resin film using a copper-clad laminate including a copper foil and a resin film laminated on one surface of the copper foil. preferable. Furthermore, it is preferable that the copper foil is etched and is a copper circuit.

  Another example of the multilayer substrate is a multilayer substrate including a circuit board and a plurality of insulating layers stacked on the surface of the circuit board. At least one of the plurality of insulating layers arranged on the circuit board is formed using a resin film obtained by forming the resin composition into a film. It is preferable that the multilayer substrate further includes a circuit laminated on at least one surface of the insulating layer formed using the resin film.

  In FIG. 1, the multilayer substrate using the resin composition which concerns on one Embodiment of this invention is typically shown with a partial notch front sectional drawing.

  In the multilayer substrate 11 shown in FIG. 1, a plurality of insulating layers 13 to 16 are laminated on the upper surface 12 a of the circuit substrate 12. Insulating layers 13-16 are hardened material layers. A metal layer 17 is formed in a partial region of the upper surface 12 a of the circuit board 12. Among the plurality of insulating layers 13 to 16, the metal layer 17 is formed in a partial region of the upper surface of the insulating layers 13 to 15 other than the insulating layer 16 located on the outer surface opposite to the circuit board 12 side. Has been. The metal layer 17 is a circuit. Metal layers 17 are respectively disposed between the circuit board 12 and the insulating layer 13 and between the stacked insulating layers 13 to 16. The lower metal layer 17 and the upper metal layer 17 are connected to each other by at least one of via hole connection and through hole connection (not shown).

  In the multilayer board | substrate 11, the insulating layers 13-16 are formed using the resin film which shape | molded the resin composition which concerns on this invention in the film form. In this embodiment, since the surfaces of the insulating layers 13 to 16 are roughened, fine holes (not shown) are formed on the surfaces of the insulating layers 13 to 16. Further, the metal layer 17 reaches the inside of the fine hole. Moreover, in the multilayer substrate 11, the width direction dimension (L) of the metal layer 17 and the width direction dimension (S) of the part in which the metal layer 17 is not formed can be made small. In the multilayer substrate 11, good insulation reliability is imparted between an upper metal layer and a lower metal layer that are not connected by via-hole connection and through-hole connection (not shown).

(Roughening treatment and swelling treatment)
It is preferable that the said resin composition is used in order to obtain the hardened | cured material processed by a roughening process or a desmear process. The cured product includes a precured product that can be further cured.

  In order to form fine irregularities on the surface of the cured product obtained by precuring the resin composition, the cured product is preferably roughened. Prior to the roughening treatment, the cured product is preferably subjected to a swelling treatment. The cured product is preferably subjected to a swelling treatment after preliminary curing and before the roughening treatment, and is further cured after the roughening treatment. However, the cured product is not necessarily subjected to the swelling treatment.

  As a method for the swelling treatment, for example, a method of treating a cured product with an aqueous solution or an organic solvent dispersion of a compound mainly composed of ethylene glycol or the like is used. The swelling liquid used for the swelling treatment generally contains an alkali as a pH adjuster or the like. The swelling liquid preferably contains sodium hydroxide. Specifically, for example, the swelling treatment is performed by treating the cured product with a 40 wt% ethylene glycol aqueous solution at a treatment temperature of 30 to 85 ° C. for 1 to 30 minutes. The swelling treatment temperature is preferably in the range of 50 to 85 ° C. When the temperature of the swelling treatment is too low, it takes a long time for the swelling treatment, and the adhesive strength between the cured product and the metal layer tends to be low.

  For the roughening treatment, for example, a chemical oxidizing agent such as a manganese compound, a chromium compound, or a persulfuric acid compound is used. These chemical oxidizers are used as an aqueous solution or an organic solvent dispersion after water or an organic solvent is added. The roughening liquid used for the roughening treatment generally contains an alkali as a pH adjuster or the like. The roughening solution preferably contains sodium hydroxide.

  Examples of the manganese compound include potassium permanganate and sodium permanganate. Examples of the chromium compound include potassium dichromate and anhydrous potassium chromate. Examples of the persulfate compound include sodium persulfate, potassium persulfate, and ammonium persulfate.

  The method for the roughening treatment is not particularly limited. As a method of the said roughening process, 30-90 g / L permanganic acid or a permanganate solution and 30-90 g / L sodium hydroxide solution are used, for example, process temperature 30-85 degreeC and 1-30 minutes. A method of treating a cured product under conditions is preferable. It is preferable that the temperature of the said roughening process exists in the range of 50-85 degreeC. The number of times of the roughening treatment is preferably once or twice.

  The arithmetic average roughness Ra of the surface of the cured product is preferably 50 nm or more, preferably 350 nm or less, more preferably less than 200 nm, still more preferably less than 100 nm. In this case, the adhesive strength between the cured product and the metal layer or wiring is increased, and further finer wiring is formed on the surface of the insulating layer.

(Desmear treatment)
A through-hole may be formed in the hardened | cured material obtained by precuring the said resin composition. In the multilayer substrate or the like, a via or a through hole is formed as a through hole. For example, the via can be formed by irradiation with a laser such as a CO ₂ laser. The diameter of the via is not particularly limited, but is about 60 to 80 μm. Due to the formation of the through hole, a smear, which is a resin residue derived from the resin component contained in the cured product, is often formed at the bottom of the via.

  In order to remove the smear, the surface of the cured product is preferably desmeared. The desmear process may also serve as a roughening process.

  In the desmear treatment, for example, a chemical oxidant such as a manganese compound, a chromium compound, or a persulfate compound is used in the same manner as the roughening treatment. These chemical oxidizers are used as an aqueous solution or an organic solvent dispersion after water or an organic solvent is added. The desmear treatment liquid used for the desmear treatment generally contains an alkali. The desmear treatment liquid preferably contains sodium hydroxide.

  The method for the desmear treatment is not particularly limited. As a method for the desmear treatment, for example, using a 30 to 90 g / L permanganate or permanganate solution and a 30 to 90 g / L sodium hydroxide solution, a treatment temperature of 30 to 85 ° C. and a condition of 1 to 30 minutes And the method of processing hardened | cured material once or twice is suitable. It is preferable that the temperature of the said desmear process exists in the range of 50-85 degreeC.

  By using the resin composition, the surface roughness of the surface of the cured product that has been desmeared is sufficiently reduced.

  Hereinafter, the present invention will be specifically described by giving examples and comparative examples. The present invention is not limited to the following examples.

  The following ingredients were used.

(Epoxy resin)
Bisphenol A type epoxy resin (DIC-made "850-S", epoxy equivalent 185, molecular weight about 400)
Dicyclopentadiene type epoxy resin (“HP-7200HH” manufactured by DIC, weight average molecular weight of about 950)
Biphenyl type epoxy resin (“NC-3000-FH” manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent 315, molecular weight about 1500)
Bisphenol A type epoxy resin (Mitsubishi Chemical "1001", epoxy equivalent 475, molecular weight about 900)
Bisphenol A type epoxy resin (Mitsubishi Chemical "1004", epoxy equivalent 924, molecular weight about 1650)

(Cyanate ester compound)
Cyanate ester resin-containing liquid A (Lonza Japan "BA-230S", solid content 75% by weight and methyl ethyl ketone 25% by weight, cyanate ester group equivalent 235)
Cyanate ester resin-containing liquid B ("BA-3000S" manufactured by Lonza Japan Co., cyanate ester group equivalent 234 containing 75 wt% solid content and 25 wt% methyl ethyl ketone)

(Phenoxy resin)
Phenoxy resin-containing liquid A (Mitsubishi Chemical "YX6954BH30", weight average molecular weight 39000), solid content 30% by weight, methyl ethyl ketone 35% by weight and cyclohexanone 35% by weight)
Phenoxy resin-containing liquid B (including Nippon Steel & Sumikin Chemical Co., Ltd. "FX-293AM40" solid content 40 wt%, methyl ethyl ketone 30 wt% and cyclohexanone 30 wt%)

(Curing accelerator)
Imidazole Compound A (“2P4MZ” manufactured by Shikoku Chemicals)
Imidazole compound B (“2E4MZ” manufactured by Shikoku Chemicals)

(Inorganic filler)
Spherical silica (Spherical silica whose surface was treated with “SO-C2” manufactured by Admatechs Corporation with a silane coupling agent having an N-phenyl-3-aminopropyl group (“KBM-573” manufactured by Shin-Etsu Chemical Co., Ltd.))

(solvent)
Cyclohexanone ("037-05096" manufactured by Wako Pure Chemical Industries, Ltd.)

Example 1
Cyanate ester compound-containing liquid A (Lonza Japan "BA-230S") 10.5 parts by weight (solid content 7.9 parts by weight) and bisphenol A type epoxy resin (DIC Corporation "850-S") 10 0.5 part by weight, 10.5 part by weight of a dicyclopentadiene type epoxy resin (“HP-7200HH” manufactured by DIC), 0.4 part by weight of an imidazole compound (“2P4MZ” manufactured by Shikoku Kasei Kogyo Co., Ltd.), and a phenoxy resin 8.6 parts by weight of liquid A (“YX6954BH30” manufactured by Mitsubishi Chemical Corporation) (2.6 parts by weight in solid content) and spherical silica (“SO-C2” manufactured by Admatechs Co., Ltd.) were added to N-phenyl-3-aminopropyl. 68.0 parts by weight of a silane coupling agent having a group (spherical silica surface-treated with “KBM-573” manufactured by Shin-Etsu Chemical Co., Ltd.) and cyclohexanone (Wako Pure Chemical Industries, Ltd.) Mixing the company made "037-05096") 42.9 parts by weight, and stirred at room temperature until a homogeneous solution, to obtain a resin composition (varnish).

  After applying the resin composition (varnish) obtained on the release-treated surface of a polyethylene terephthalate (PET) film (“XG284” manufactured by Toray Industries Inc., thickness 25 μm) using an applicator, in a gear oven at 100 ° C. For 2 minutes to evaporate the solvent. In this way, a resin film (B stage film) having a thickness of 40 μm and a residual solvent amount of 1.0 wt% or more and 4.0 wt% or less was obtained on the PET film.

  Moreover, it carried out similarly to the resin film of thickness 40 micrometers, and obtained the resin film (B stage film) whose thickness is 15 micrometers and whose residual amount of a solvent is 1.0 weight% or more and 4.0 weight% or less.

(Examples 2 to 10 and Comparative Examples 1 to 4)
The resin composition (varnish) and the resin film (B stage film) were the same as in Example 1 except that the types and amounts (parts by weight) of the components used were changed as shown in Tables 1 and 2 below. ) Was produced.

(Evaluation)
(1) Ratio (number of epoxy groups / total number of alcoholic hydroxyl groups)
The amount of epoxy groups of the epoxy resin in 100 g of the resin composition and the total amount of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in 100 g of the resin composition were determined. The ratio of the number of epoxy groups of the epoxy resin in the obtained resin composition to the total number of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in the obtained resin composition was determined.

(2) Storage stability The laminated body of the obtained PET film and resin film (thickness 40 micrometers) was stored at 25 degreeC for 5 days.

  2-1) The resin film (thickness 40 μm) was peeled from the PET film, and the presence or absence of whitening and cracking in the bending test when the resin film after storage was bent 180 degrees was evaluated. Judgment was made according to the following criteria.

[Whether or not whitening and cracking occurred in the bending test]
○: Neither whitening nor cracking occurred ×: Either whitening or cracking occurred

  2-2) The resin film (thickness 40 μm) is peeled off from the PET film, and the stored resin film is cut into a size of 50 mm in length × 100 mm in width with a cutter to check for cracks or chipping in the cutting test. evaluated. Judgment was made according to the following criteria.

[Presence or absence of crack or chip in cutting test]
○: Neither crack nor chip occurred in the resin film after cutting ×: Either crack or chip occurred in the resin film after cutting

  2-3) A copper-clad laminate (a laminate of a 150 μm thick glass epoxy substrate and a 35 μm thick copper foil) was prepared. The copper foil was etched to produce 26 copper patterns having an L / S of 50 μm / 50 μm and a length of 1 cm to obtain an uneven substrate. The obtained resin film (thickness: 40 μm) is stacked on the uneven surface of the uneven substrate, and using a vacuum pressure laminator machine (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.), laminating pressure 0.4 MPa and laminating temperature 90 ° C. For 20 seconds, and further pressed at a press pressure of 0.8 MPa and a press temperature of 90 ° C. for 20 seconds. Thus, the laminated body A by which the resin film was laminated | stacked on the uneven substrate was obtained. In the state of the laminate A, the unevenness value of the upper surface of the resin film in the laminate A was measured using “WYKO” manufactured by Beco. Specifically, the maximum value of the height difference between the concave and convex portions adjacent to the concave and convex portions was adopted as the concave and convex value. Thus, the presence or absence of the uneven | corrugated state in the lamination test was evaluated. Judgment was made according to the following criteria.

[Presence / absence of unevenness in laminate test]
○: Uneven value is 0.3 μm or less Δ: Uneven value exceeds 0.3 μm, 0.5 μm or less X: Uneven value exceeds 0.5 μm

(3) Surface roughness of the surface of the cured product Laminate surface treatment:
Both surfaces of a glass epoxy substrate (“CS-3665” manufactured by Risho Kogyo Co., Ltd.) on which an inner layer circuit has been formed by etching are immersed in a copper surface roughening agent (“MEC Etch Bond CZ-8100” manufactured by MEC) to immerse the copper surface. Roughening treatment was performed.

laminate:
The obtained laminate of PET film and resin film (thickness 40 μm) is set on both sides of the glass epoxy substrate from the resin film side, and a diaphragm type vacuum laminator (“MVLP-500” manufactured by Meiki Seisakusho Co., Ltd.) is used. And laminated on both sides of the glass epoxy substrate. Lamination was performed by reducing the pressure for 20 seconds to a pressure of 13 hPa or less, and then pressing for 20 seconds at 100 ° C. and a pressure of 0.8 MPa.

Resin film curing:
The PET film was peeled from the resin film. Next, the resin film was cured under curing conditions of 170 ° C. and 60 minutes to obtain a laminated sample.

Swelling treatment:
The above laminated sample is put in a swelling solution at 60 ° C. (an aqueous solution containing “Swelling Dip Securigant P” manufactured by Atotech Japan Co., Ltd.) and “sodium hydroxide” manufactured by Wako Pure Chemical Industries, Ltd. Rocked for minutes. Thereafter, it was washed with pure water.

Roughening treatment (permanganate treatment):
Put the above laminated sample swollen into 80 ° C sodium permanganate roughening aqueous solution ("Concentrate Compact CP" manufactured by Atotech Japan, "Sodium hydroxide" manufactured by Wako Pure Chemical Industries, Ltd.), and roughening temperature Rocked at 80 ° C. for 20 minutes. Then, after washing | cleaning for 10 minutes with a 40 degreeC washing | cleaning liquid ("Reduction securigant P" by the Atotech Japan company, "Sulfuric acid" by Wako Pure Chemical Industries Ltd.), it wash | cleaned further with the pure water. In this way, a roughened cured product was formed on the glass epoxy substrate on which the inner layer circuit was formed by etching.

  Further, a roughened cured product was formed on a glass epoxy substrate (substrate with metal) on which an inner layer circuit was formed in the same manner except that the resin film having a thickness of 40 μm was changed to a resin film having a thickness of 15 μm.

  The arithmetic average roughness Ra was measured for each of the case where a resin film having a thickness of 40 μm was used and the case where a resin film having a thickness of 15 μm was used. The arithmetic average roughness Ra of the surface of the roughened cured product was measured using a non-contact type surface roughness meter (“WYKO” manufactured by Beiko). Arithmetic average roughness Ra was based on JIS B0601-1994.

[Criteria for surface roughness of cured product]
○: Ra is less than 100 nm Δ: Ra is 100 nm or more and less than 200 nm ×: Ra is 200 nm or more

(4) Uniformity of curing of resin film on substrate with metal From the measurement result of surface roughness of cured product in evaluation of surface roughness of (3) surface of cured product, resin on substrate with metal The curing uniformity of the film was determined according to the following criteria.

[Hardness uniformity of resin film on metal substrate]
○: The absolute value of the difference between Ra when the thickness is 15 μm and Ra when the thickness is 40 μm is less than 50 nm Δ: The absolute value of the difference between Ra when the thickness is 15 μm and Ra when the thickness is 40 μm is 50 nm or more and 100 nm Less than ×: The absolute value of the difference between Ra when the thickness is 15 μm and Ra when the thickness is 40 μm is 100 nm or more

(5) Adhesive strength (peel strength)
A roughened cured product obtained by measuring the surface roughness of the surface of (3) cured product was prepared.

Electroless plating treatment:
The surface of the roughened cured product was treated with a 60 ° C. alkali cleaner (“Cleaner Securigant 902” manufactured by Atotech Japan) for 5 minutes and degreased and washed. After washing, the cured product was treated with a 25 ° C. pre-dip solution (“Pre-Dip Neogant B” manufactured by Atotech Japan) for 2 minutes. Thereafter, the cured product was treated with an activator solution at 40 ° C. (“Activator Neo Gantt 834” manufactured by Atotech Japan) for 5 minutes to attach a palladium catalyst. Next, the cured product was treated with a reducing solution at 30 ° C. (“Reducer Neogant WA” manufactured by Atotech Japan) for 5 minutes.

  Next, the cured product is put into a chemical copper solution (all manufactured by Atotech Japan “Basic Print Gantt MSK-DK”, “Copper Print Gantt MSK”, “Stabilizer Print Gantt MSK”, “Reducer Cu”). Was carried out until the plating thickness reached about 0.5 μm. After the electroless plating, annealing was performed at a temperature of 120 ° C. for 30 minutes in order to remove the remaining hydrogen gas. All the steps up to the electroless plating step were performed with a treatment liquid of 2 L on a beaker scale and while the cured product was swung.

Next, electrolytic plating was performed on the cured product that had been subjected to electroless plating until the plating thickness reached 25 μm. As an electrolytic copper plating, a copper sulfate solution (“copper sulfate pentahydrate” manufactured by Wako Pure Chemical Industries, Ltd., “sulfuric acid” manufactured by Wako Pure Chemical Industries, Ltd., “basic leveler kaparaside HL” manufactured by Atotech Japan Co., Ltd., “ using the correction agent Cupracid GS "), plating thickness passing a current of 0.6 a / cm ² was carried out electrolytic plating until approximately 25 [mu] m. After the copper plating treatment, the cured product was heated at 190 ° C. for 2 hours to further cure the cured product. Thus, the hardened | cured material with which the copper plating layer was laminated | stacked on the upper surface was obtained.

  In the cured product obtained by laminating the obtained copper plating layer, a 10 mm wide cutout was made on the surface of the copper plating layer. Thereafter, using a tensile tester (“AG-5000B” manufactured by Shimadzu Corporation), the adhesive strength (peel strength) between the cured product and the copper plating layer was measured under the condition of a crosshead speed of 5 mm / min.

[Criteria for adhesive strength]
○: 5.9 N / cm or more Δ: 4.9 N / cm or more, less than 5.9 N / cm ×: less than 4.9 N / cm

(6) Average linear expansion coefficient (CTE)
The resin film (thickness 40 μm) obtained on the PET film was cured under curing conditions of 170 ° C. and 60 minutes, and further heated at 190 ° C. for 2 hours. Thereafter, the PET film was peeled off to obtain a cured product. The obtained cured product was cut into a size of 3 mm × 25 mm. Using a thermomechanical analyzer (“EXSTAR TMA / SS6100” manufactured by SII Nano Technology), the cured product cut at 25 ° C. to 150 ° C. under the conditions of a tensile load of 33 mN and a heating rate of 5 ° C./min. The average linear expansion coefficient (ppm / ° C.) was calculated.

[Criteria for average linear expansion coefficient]
○: Average linear expansion coefficient is 35 ppm / ° C. or less ×: Average linear expansion coefficient exceeds 35 ppm / ° C.

  The compositions and results are shown in Tables 1 and 2 below. In the above (4) evaluation of the curing uniformity of the resin film on the substrate with metal, a resin film having a thickness of 15 μm and a resin film having a thickness of 40 μm were used. When the thickness of the resin film using the resin composition of an Example is in the range of 5 to 200 μm, it was confirmed that the curing uniformity was particularly excellent.

DESCRIPTION OF SYMBOLS 11 ... Multilayer substrate 12 ... Circuit board 12a ... Upper surface 13-16 ... Insulating layer 17 ... Metal layer (wiring)

Claims (11)

A resin composition used to obtain a resin film by molding into a film,
Including an epoxy resin, a cyanate ester compound, a phenoxy resin, and a curing accelerator,
The resin composition in which the ratio of the number of epoxy groups of the epoxy resin in the resin composition to the total number of alcoholic hydroxyl groups of the epoxy resin and the phenoxy resin in the resin composition is 10 or more and 30 or less.   The resin composition of Claim 1 whose content of the said hardening accelerator is 0.01 to 3.0 weight% in 100 weight% of total solid content contained in a resin composition.   The resin composition of Claim 1 or 2 whose content of the said cyanate ester compound is 20 to 100 weight part with respect to a total of 100 weight part of the said epoxy resin and the said phenoxy resin.   The resin composition of any one of Claims 1-3 whose molecular weight of the said epoxy resin is 200 or more and 3000 or less.   The resin composition of any one of Claims 1-4 whose weight average molecular weights of the said phenoxy resin are 5000 or more and 100,000 or less.   The resin composition according to claim 1, further comprising an inorganic filler.   The resin composition according to claim 6, wherein the inorganic filler is silica.   The resin composition according to claim 6 or 7, wherein the content of the inorganic filler is 40% by weight or more and 85% by weight or less in 100% by weight of the total solid content contained in the resin composition.   The resin composition of any one of Claims 1-8 used in order to obtain the hardened | cured material processed by a roughening process or a desmear process.   The resin film obtained by shape | molding the resin composition of any one of Claims 1-9 in a film form. A circuit board;
An insulating layer disposed on the circuit board,
The multilayer substrate in which the said insulating layer is formed using the resin film obtained by shape | molding the resin composition of any one of Claims 1-9 in a film form.

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