Resin Sheet

Abstract

The problem of the present invention is to provide: a resin sheet that suppresses the appearance of the resin composition layer even if the thickness of the resin composition layer is thick; a circuit board using the resin sheet, and a semiconductor chip package. The solution of the present invention is a resin sheet comprising a support body and a resin composition layer provided on the support body, wherein the thickness of the resin composition layer is 60 μm or more, and the length of the support body when joined to the resin composition layer is set to L A , and the length of the support after the support is peeled off from the resin composition layer is defined as L B When L A / L B The relationship of 1.005 or more and 1.2 or less is satisfied.

Description

Technical Field

[0001] The present invention relates to a resin sheet and further to a circuit board and a semiconductor chip package using the resin sheet. Background Art

[0002] In recent years, the demand for high-function electronic devices such as smartphones and tablet devices has increased, and along with this, insulating materials that can be used as sealing layers or insulating layers of these electronic devices are also required to have further high functions.

[0003] As insulating materials, generally, a resin sheet having a resin composition layer provided on a support can be used. For example, Patent Document 1 discloses a sealing sheet having a resin composition layer as an insulating material provided on a support for sealing components contained in a circuit board.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent document 1: Japanese Patent Application Publication No. 2018-162418. Summary of the invention

[0007] Problems to be solved by the invention

[0008] When the resin composition layer in the resin sheet is used as a sealing layer, the thickness of the resin composition layer may be insufficient, and thus the built-in components of the electronic device may not be sufficiently sealed. Therefore, the thickness of the resin composition layer may be increased.

[0009] However, if the thickness of the resin composition layer is large, the appearance of the resin composition layer may be poor.

[0010] The present invention has been made in view of the above problems, and an object of the present invention is to provide a resin sheet which suppresses the appearance defect of the resin composition layer even if the resin composition layer is thick, and a circuit board and a semiconductor chip package using the resin sheet.

[0011] Means for solving problems

[0012] The present inventors have conducted intensive research to solve the above-mentioned problems, and as a result, have found that the poor appearance of the resin composition is caused by the transfer of wrinkles generated on the support to the resin composition layer. In addition, the present inventors have found that a resin sheet whose length of the support when bonded to the resin composition layer and the length of the support after the support is peeled off from the resin composition layer satisfy a predetermined relationship can suppress the formation of wrinkles on the support, and therefore, even if the thickness of the resin composition layer is thick, the poor appearance of the resin composition layer can be suppressed, thereby completing the present invention.

[0013] That is, the present invention includes the following contents:

[0014] [1] A resin sheet comprising a first support and a resin composition layer bonded to the first support,

[0015] The thickness of the resin composition layer is 60 μm or more.

[0016] The ratio L of one or more in-plane directions of the support A / L B Satisfying the relationship of 1.005 or more and 1.2 or less,

[0017] L A represents the length of the first support in the aforementioned in-plane direction when bonded to the resin composition layer,

[0018] L B represents the length of the first support in the aforementioned in-plane direction after being peeled off from the resin composition layer;

[0019] [2] The resin sheet according to [1], wherein the resin sheet comprises a first support, a resin composition layer, and a second support in this order;

[0020] [3] The resin sheet according to [1] or [2], wherein the minimum melt viscosity of the resin composition layer at 60°C to 200°C is 1000 poise or more and 20000 poise or less;

[0021] [4] The resin sheet according to any one of [1] to [3], wherein, when the minimum melt viscosity of the resin composition layer at 60°C to 200°C is M (poise) and the thickness of the resin composition layer is T (μm), M / T satisfies the relationship of 5 or more and 200 or less;

[0022] [5] A circuit board comprising an insulating layer formed from a cured product of the resin composition layer in the resin sheet according to any one of [1] to [4];

[0023] [6] A semiconductor chip package comprising: the circuit substrate described in [5], and a semiconductor chip mounted on the circuit substrate;

[0024] [7] A semiconductor chip package comprising: a semiconductor chip; and a cured product of the resin composition layer in the resin sheet according to any one of [1] to [4], which seals the semiconductor chip.

[0025] Effects of the Invention

[0026] According to the present invention, there can be provided a resin sheet which suppresses the appearance defect of the resin composition layer even if the resin composition layer is thick, and a circuit board and a semiconductor chip package using the resin sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic cross-sectional view of a resin sheet of the present invention;

[0028] Figure 2 This is a schematic cross-sectional view of the resin sheet of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be described in detail below with reference to the embodiments and examples. However, the present invention is not limited to the embodiments and examples listed below, and can be implemented with any changes within the scope of the claims and their equivalents.

[0030] [Resin composition]

[0031] Before describing the resin sheet of the present invention in detail, the resin composition used when forming the resin composition layer will be described.

[0032] Regarding the resin composition used when forming the resin composition layer, its cured product may have sufficient insulation. In one embodiment, the resin composition includes (A) a curable resin. As required, the resin composition may further include (B) an inorganic filler, (C) a curing accelerator, (D) a thermoplastic resin, (E) an amphiphilic polyether block copolymer, (F) an elastomer, and (G) other additives. Hereinafter, each component included in the resin composition is described in detail.

[0033] <(A) Curable resin>

[0034] The resin composition contains (A) a curable resin as the (A) component. As the (A) curable resin, any curable resin that can be used when forming an insulating layer of a printed wiring board can be used, and a thermosetting resin is preferred.

[0035] As curable resins, for example, epoxy resins, phenolic resins, naphthol resins, benzoxazine resins, active ester resins, cyanate resins, carbodiimide resins, amine resins, anhydride resins, etc. can be cited. (A) component can be used alone or in combination of two or more in any ratio. Hereinafter, resins such as phenolic resins, naphthol resins, benzoxazine resins, active ester resins, cyanate resins, carbodiimide resins, amine resins, anhydride resins that can react with epoxy resins to cure the resin composition are sometimes collectively referred to as "curing agents". As the resin composition, it is preferred to include epoxy resins and curing agents as (A) components.

[0036] The epoxy resin as the component (A) includes, for example, bixylenol epoxy resin, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol S epoxy resin, bisphenol AF epoxy resin, dicyclopentadiene epoxy resin, trisphenol epoxy resin, naphthol novolac epoxy resin, phenol novolac epoxy resin, tert-butyl-catechol epoxy resin, naphthalene epoxy resin, naphthol epoxy resin, anthracene epoxy resin, The epoxy resins include epoxy resins of the type butylene oxide, ...

[0037] For the resin composition, as component (A), an epoxy resin having two or more epoxy groups in one molecule is preferably included. From the viewpoint of significantly obtaining the desired effect of the present invention, relative to 100% by mass of the non-volatile component of component (A), the proportion of the epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 70% by mass or more.

[0038] Epoxy resins include epoxy resins that are liquid at a temperature of 20° C. (hereinafter sometimes referred to as “liquid epoxy resins”) and epoxy resins that are solid at a temperature of 20° C. (hereinafter sometimes referred to as “solid epoxy resins”). The resin composition may contain only a liquid epoxy resin, only a solid epoxy resin, or a combination of a liquid epoxy resin and a solid epoxy resin as component (A).

[0039] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred.

[0040] As liquid epoxy resins, preferred are bisphenol A type epoxy resins, bisphenol F type epoxy resins, bisphenol AF type epoxy resins, naphthalene type epoxy resins, glycidyl ester type epoxy resins, glycidyl amine type epoxy resins, phenol novolac type epoxy resins, alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resins, cyclohexanedimethanol type epoxy resins, glycidyl amine type epoxy resins, and epoxy resins having a butadiene structure, and bisphenol A type epoxy resins and bisphenol F type epoxy resins are more preferred.

[0041] Specific examples of liquid epoxy resins include "HP4032", "HP4032D", and "HP4032SS" (naphthalene-type epoxy resins) manufactured by DIC Corporation; "828US", "jER828EL", "825", and "EPIKOTE 828EL" (bisphenol A-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER807" and "1750" (bisphenol F-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "jER152" (phenol novolac-type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "630" and "630LSD" (glycidylamine-type epoxy resins) manufactured by Mitsubishi Chemical Corporation; "ZX1059" (a mixture of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; Nagase "EX-721" (glycidyl ester type epoxy resin) manufactured by ChemteX Co., Ltd.; "Celloxide 2021P" (alicyclic epoxy resin with ester skeleton) manufactured by Daicel Corporation; "PB-3600" (epoxy resin with butadiene structure) manufactured by Daicel Corporation; "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd. These can be used alone or in combination of two or more.

[0042] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups in one molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups in one molecule is more preferred.

[0043] As the solid epoxy resin, preferred are biphenylol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin, and more preferred is naphthalene-type epoxy resin.

[0044] As solid epoxy resins, preferred are naphthalene-type tetrafunctional epoxy resins, cresol novolac-type epoxy resins, dicyclopentadiene-type epoxy resins, trisphenol-type epoxy resins, naphthol-type epoxy resins, biphenyl-type epoxy resins, naphthylene ether-type epoxy resins, anthracene-type epoxy resins, bisphenol A-type epoxy resins, and tetraphenylethane-type epoxy resins, and more preferred are naphthalene-type tetrafunctional epoxy resins, naphthol-type epoxy resins, and biphenyl-type epoxy resins. Specific examples of the solid epoxy resin include “HP4032H” (naphthalene type epoxy resin), “HP-4700”, “HP-4710” (naphthalene type tetrafunctional epoxy resin), “N-690” (cresol novolac type epoxy resin), “N-695” (cresol novolac type epoxy resin), “HP-7200”, “HP-7200HH”, “HP-7200H” (dicyclopentadiene type epoxy resin), “EXA-7311”, “EXA-7311-G3”, “EXA-7311-G4”, “EXA-7311-G4S”, and “HP6000” (naphthylene ether type epoxy resin) manufactured by DIC Corporation; “EPPN-502H” (trisphenol type epoxy resin), “NC7000L” (naphthol novolac type epoxy resin), and “NC30 00H", "NC3000", "NC3000L", "NC3100" (biphenyl type epoxy resin); "ESN475V" (naphthalene type epoxy resin), "ESN485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical Materials Co., Ltd.; "YX4000H", "YL6121" (biphenyl type epoxy resin), "YX4000HK" (biphenyl type epoxy resin), "YX8800" (anthracene type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "PG-100", "CG-500" manufactured by Osaka Gas Chemical Co., Ltd., "YL7760" (bisphenol AF type epoxy resin), "YL7800" (fluorene type epoxy resin) manufactured by Mitsubishi Chemical Corporation, "jER1010" (solid bisphenol A type epoxy resin), "jER1031S" (tetraphenylethane type epoxy resin), etc. These may be used alone or in combination of two or more.

[0045] When a liquid epoxy resin and a solid epoxy resin are used in combination as component (A), their amount ratio (liquid epoxy resin: solid epoxy resin) is preferably 1:0.1 to 1:20 by mass ratio, more preferably 1:0.3 to 1:15, and particularly preferably 1:0.5 to 1:10. By making the amount ratio of the liquid epoxy resin to the solid epoxy resin within the above range, the desired effect of the present invention can be significantly obtained. Furthermore, usually, when used in the form of an adhesive film, moderate adhesion can be achieved. In addition, usually, when used in the form of an adhesive film, sufficient flexibility can be obtained and the handleability is improved. Furthermore, usually, a cured product with sufficient breaking strength can be obtained.

[0046] The epoxy equivalent of the epoxy resin as component (A) is preferably 50 g / eq. to 5000 g / eq., more preferably 50 g / eq. to 3000 g / eq., further preferably 80 g / eq. to 2000 g / eq., and further more preferably 110 g / eq. to 1000 g / eq. By becoming the above range, the crosslinking density of the cured product of the resin composition becomes sufficient, and an insulating layer with a small surface roughness can be formed. The epoxy equivalent is the mass of the epoxy resin containing 1 equivalent of epoxy groups. The epoxy equivalent can be measured according to JIS K7236.

[0047] From the viewpoint of significantly obtaining the desired effects of the present invention, the weight average molecular weight (Mw) of the epoxy resin as the component (A) is preferably 100 to 5000, more preferably 250 to 3000, and even more preferably 400 to 1500. The weight average molecular weight of the epoxy resin is a weight average molecular weight measured by gel permeation chromatography (GPC) in terms of polystyrene conversion.

[0048] From the viewpoint of obtaining an insulating layer showing good mechanical strength and insulation reliability, when the non-volatile component in the resin combination is set to 100% by mass, the content of the epoxy resin as component (A) is preferably more than 1% by mass, more preferably more than 3% by mass, and further preferably more than 5% by mass. From the viewpoint of significantly obtaining the desired effect of the present invention, the upper limit of the content of the epoxy resin is preferably less than 45% by mass, more preferably less than 40% by mass, and particularly preferably less than 35% by mass.

[0049] As for the active ester resin as component (A), a resin having one or more active ester groups in one molecule can be used. Among them, as the active ester resin, preferably a resin having two or more highly reactive ester groups in one molecule such as phenolic esters, thiophenolic esters, N-hydroxylamine esters, esters of heterocyclic hydroxy compounds, etc. The active ester resin is preferably obtained by a condensation reaction of a carboxylic acid compound and / or a thiocarboxylic acid compound with a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improved heat resistance, an active ester resin obtained from a carboxylic acid compound and a hydroxy compound is preferably used, and an active ester resin obtained from a carboxylic acid compound and a phenolic compound and / or a naphthol compound is more preferably used.

[0050] Examples of the carboxylic acid compound include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, and pyromellitic acid.

[0051] Examples of the phenol compound or naphthol compound include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucinol, pyrogallol, dicyclopentadiene-type diphenol compounds, phenol novolac, etc. Here, the so-called "dicyclopentadiene-type diphenol compound" refers to a diphenol compound obtained by condensing two molecules of phenol on one molecule of dicyclopentadiene.

[0052] Preferred specific examples of active ester resins include active ester resins containing a dicyclopentadiene diphenol structure, active ester resins containing a naphthalene structure, active ester resins containing acetylated products of phenol novolac, and active ester resins containing benzoylated products of phenol novolac. Among them, active ester resins containing a naphthalene structure and active ester resins containing a dicyclopentadiene diphenol structure are more preferred. The so-called "dicyclopentadiene diphenol structure" refers to a divalent structural unit formed by phenylene-dicyclopentylene (dicyclopentylene)-phenylene.

[0053] Examples of commercially available active ester resins include: "EXB9451", "EXB9460", "EXB9460S", "HPC-8000-65T", "HPC-8000H-65TM", and "EXB-8000L-65TM" (manufactured by DIC Corporation), which are active ester resins containing a dicyclopentadiene-type diphenol structure; "EXB-8100L-65T", "EXB-8150L-65T", "EXB9416-70BK", "EXB-8150-65T", "HPC-8150-60T", "HPC-8150-62T", and "EXB-8100L-65T" and "EXB-8150L-65T" which are active ester resins containing a naphthalene structure. XB-8150-65T" (manufactured by DIC Corporation); "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing an acetylated product of phenol novolac; "YLH1026" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin containing a benzoylated product of phenol novolac; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin of an acetylated product of phenol novolac; "YLH1026" (manufactured by Mitsubishi Chemical Corporation), "YLH1030" (manufactured by Mitsubishi Chemical Corporation), "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins of benzoylated products of phenol novolac; and the like.

[0054] As for the phenolic resin and naphthol resin as the component (A), from the viewpoint of heat resistance and water resistance, a resin having a novolac structure is preferred. In addition, from the viewpoint of adhesion with the conductor layer, a nitrogen-containing phenolic curing agent is preferred, and a phenolic resin containing a triazine skeleton is more preferred.

[0055] Specific examples of phenol-based resins and naphthol-based resins include, for example, "MEH-7700", "MEH-7810", and "MEH-7851" manufactured by Meiwa Chemicals Co., Ltd., "NHN", "CBN", and "GPH" manufactured by Nippon Kayaku Co., Ltd., "SN170", "SN180", "SN190", "SN475", "SN485", "SN495", "SN-495V", "SN375", and "SN395" manufactured by Nippon Steel Chemicals Co., Ltd., and "TD-2090", "LA-7052", "LA-7054", "LA-1356", "LA-3018-50P", and "EXB-9500" manufactured by DIC Corporation.

[0056] Specific examples of the benzoxazine resin as the component (A) include "JBZ-OD100" (benzoxazine ring equivalent: 218), "JBZ-OP100D" (benzoxazine ring equivalent: 218), and "ODA-BOZ" (benzoxazine ring equivalent: 218) manufactured by JFE Chemical Co., Ltd.; "Pd" (benzoxazine ring equivalent: 217) and "Fa" (benzoxazine ring equivalent: 217) manufactured by Shikoku Chemical Industry Co., Ltd.; and "HFB2006M" (benzoxazine ring equivalent: 432) manufactured by Showa High Molecular Co., Ltd.

[0057] The cyanate resin as the component (A) includes, for example, difunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenylcyanate), 4,4'-ethylenediphenyl 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-(methylethylene))benzene, bis(4-cyanatephenyl)sulfide, and bis(4-cyanatephenyl)ether; polyfunctional cyanate resins derived from phenol novolac and cresol novolac; prepolymers obtained by partially triazinizing these cyanate resins; and the like. Specific examples of cyanate ester resins include "PT30", "PT30S" and "PT60" manufactured by Lonza Japan Co., Ltd. (phenol novolac type multifunctional cyanate resins), "ULL-950S" (multifunctional cyanate resin), "BA230", "BA230S75" (prepolymers obtained by triazine-forming a part or all of bisphenol A dicyanate to form a trimer), etc.

[0058] Specific examples of the carbodiimide resin as the component (A) include CARBODILITE (registered trademark) V-03 (carbodiimide group equivalent: 216, V-05 (carbodiimide group equivalent: 216); V-07 (carbodiimide group equivalent: 200); V-09 (carbodiimide group equivalent: 200) manufactured by Nisshinbo Chemical Co., Ltd.; and Stabaxol (registered trademark) P (carbodiimide group equivalent: 302) manufactured by Rhein Chemie.

[0059] As for the amine resin as the component (A), resins having one or more amino groups in one molecule can be cited, and examples thereof include aliphatic amines, polyether amines, alicyclic amines, aromatic amines, etc. Among them, aromatic amines are preferred from the viewpoint of exerting the desired effect of the present invention. The amine resin is preferably a primary amine or a secondary amine, and more preferably a primary amine. Specific examples of amine curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, metaphenylenediamine, metaphenylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, 2,2-bis(3-amino- 4-hydroxyphenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-aminophenyl)propane, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. As the amine resin, commercially available products may be used, and examples thereof include "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", and "KAYAHARD AS" manufactured by Nippon Kayaku Co., Ltd. and "Epicure W" manufactured by Mitsubishi Chemical Corporation.

[0060] The acid anhydride resin as component (A) includes resins having one or more acid anhydride groups in one molecule. Specific examples of the acid anhydride resin include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenylsuccinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, trimellitic anhydride, pyromellitic anhydride, diphenyl Acid anhydrides of polymer type such as ketone tetracarboxylic dianhydride, biphenyl tetracarboxylic dianhydride, naphthalene tetracarboxylic dianhydride, oxydiphthalic dianhydride, 3,3'-4,4'-diphenylsulfone tetracarboxylic dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-c]furan-1,3-dione, ethylene glycol bis(trimellitic anhydride), styrene-maleic acid resin obtained by copolymerization of styrene and maleic acid, etc.

[0061] When the component (A) contains an epoxy resin and a curing agent, the amount ratio of the epoxy resin to the total curing agent is preferably in the range of 1:0.01 to 1:5, more preferably 1:0.3 to 1:3, and further preferably 1:0.5 to 1:2, in terms of the ratio of [the total number of epoxy groups of the epoxy resin]:[the total number of reactive groups of the curing agent]. The "number of epoxy groups of the epoxy resin" referred to herein refers to the value obtained by adding up all the values ​​obtained by dividing the mass of the non-volatile components of the epoxy resin present in the resin composition by the epoxy equivalent. In addition, the "number of active groups of the curing agent" refers to the value obtained by adding up all the values ​​obtained by dividing the mass of the non-volatile components of the curing agent present in the resin composition by the active group equivalent. As the component (B), by making the amount ratio of the epoxy resin to the curing agent within the above range, an insulating layer with excellent flexibility can be obtained.

[0062] From the viewpoint of obtaining an insulating layer with excellent flexibility, the content of the curing agent as the component (A) is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, further preferably 1% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, further preferably 30% by mass or less, relative to 100% by mass of the non-volatile components in the resin composition.

[0063] <(B) Inorganic fillers>

[0064] For the resin composition, as an arbitrary component, an inorganic filler can be contained as component (B). As the material of the (B) inorganic filler, an inorganic compound is used. As examples of the material of the inorganic filler, silicon dioxide, aluminum oxide, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium phosphotungstate, etc., can be cited. Among these, silicon dioxide is particularly preferred. As silicon dioxide, for example, amorphous silicon dioxide, fused silica, crystalline silicon dioxide, synthetic silicon dioxide, hollow silica, etc. can be cited. In addition, as silicon dioxide, spherical silicon dioxide is preferred. (B) The inorganic filler may be used alone or in combination of two or more.

[0065] Commercially available products of (B) inorganic fillers include, for example, "SP60-05" and "SP507-05" manufactured by Nippon Steel & Sumitomo Metal Materials Corporation; "YC100C", "YA050C", "YA050C-MJE", and "YA010C" manufactured by Admatechs Corporation; "UFP-30" manufactured by DENKA Corporation; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" manufactured by Tokuyama Corporation; "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" manufactured by Admatechs Corporation; and the like.

[0066] From the viewpoint of significantly obtaining the desired effect of the present invention, the average particle size of the inorganic filler (B) is preferably 0.01 μm or more, more preferably 0.05 μm or more, particularly preferably 0.1 μm or more, preferably 5 μm or less, more preferably 2 μm or less, and further preferably 1 μm or less.

[0067] (B) The average particle size of the inorganic filler can be measured by the laser diffraction-scattering method based on the Mie scattering theory. Specifically, it can be measured in the following manner: using a laser diffraction scattering particle size distribution measuring device, the particle size distribution of the inorganic filler is made on a volume basis, and the median particle size is used as the average particle size. The sample can be measured using a sample obtained in the following manner: 100 mg of inorganic filler and 10 g of methyl ethyl ketone are weighed into a vial and dispersed for 10 minutes using ultrasound. For the sample, a laser diffraction particle size distribution measuring device is used, and the wavelength of the light source used is set to blue and red. The particle size distribution of the volume basis of the inorganic filler (B) is measured in a flow cell, and the average particle size is calculated from the obtained particle size distribution as the median particle size. As a laser diffraction particle size distribution measuring device, for example, "LA-960" made by Horiba, Ltd. can be cited.

[0068] From the viewpoint of significantly obtaining the desired effect of the present invention, the specific surface area of ​​the inorganic filler (B) is preferably 1 m 2 / g or more, more preferably 2m 2 / g or more, particularly preferably 3m 2 There is no particular upper limit, but it is preferably 60 m 2 / g or less, 50m 2 / g or below or 40m 2The specific surface area can be obtained by adsorbing nitrogen on the surface of the sample using a specific surface area measuring apparatus (Macsorb HM-1210 manufactured by Mountech Co., Ltd.) according to the BET method, and calculating the specific surface area by the BET multipoint method.

[0069] For (B) inorganic filler, from the viewpoint of improving moisture resistance and dispersibility, it is preferably treated with a surface treatment agent. As the surface treatment agent, for example, silane coupling agents, aminosilane coupling agents, epoxysilane coupling agents, mercaptosilane coupling agents, silane coupling agents, alkoxysilanes, organosilazane compounds, titanate coupling agents, etc. containing fluorine can be cited. In addition, the surface treatment agent can be used alone or in combination of two or more.

[0070] Commercially available products of the surface treatment agent include, for example, “KBM403” (3-glycidoxypropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM803” (3-mercaptopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBE903” (3-aminopropyltriethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM573” (N-phenyl-3-aminopropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “SZ-31” (hexamethyldisilazane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM103” (phenyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd., “KBM-4803” (long-chain epoxy-type silane coupling agent) manufactured by Shin-Etsu Chemical Co., Ltd., and “KBM-7103” (3,3,3-trifluoropropyltrimethoxysilane) manufactured by Shin-Etsu Chemical Co., Ltd.

[0071] From the viewpoint of improving the dispersibility of the inorganic filler, it is preferred that the degree of surface treatment performed by the surface treatment agent is within a specified range. Specifically, for 100 parts by mass of the inorganic filler, it is preferred that 0.2 to 5 parts by mass of the surface treatment agent be used for surface treatment, preferably 0.2 to 3 parts by mass, preferably 0.3 to 2 parts by mass.

[0072] The degree of surface treatment by the surface treatment agent can be evaluated by the amount of carbon per unit surface area of ​​the inorganic filler. From the viewpoint of improving the dispersibility of the inorganic filler, the amount of carbon per unit surface area of ​​the inorganic filler is preferably 0.02 mg / m 2 More preferably 0.1 mg / m 2 More preferably, 0.2 mg / m 2 On the other hand, from the viewpoint of suppressing the increase in the melt viscosity of the resin varnish and the melt viscosity of the resin sheet layer, 1 mg / m2 Below, more preferably 0.8 mg / m 2 Below, more preferably 0.5 mg / m 2 the following.

[0073] The amount of carbon per unit surface area of ​​the inorganic filler can be measured after washing the surface-treated inorganic filler with a solvent (e.g., methyl ethyl ketone (MEK)). Specifically, a sufficient amount of MEK as a solvent can be added to the inorganic filler surface-treated with a surface treatment agent, and ultrasonic washing is performed at 25°C for 5 minutes. The supernatant is removed, the solid component is dried, and then the amount of carbon per unit surface area of ​​the inorganic filler is measured using a carbon analyzer. As a carbon analyzer, "EMIA-320V" manufactured by Horiba, Ltd. can be used.

[0074] From the viewpoint of obtaining an insulating layer with a low dielectric loss tangent, when the non-volatile component in the resin composition is set to 100 mass %, the content of the (B) inorganic filler is preferably 10 mass % or more, more preferably 15 mass % or more, further preferably 20 mass % or more, preferably 90 mass % or less, more preferably 88 mass % or less, and further preferably 85 mass % or less.

[0075] <(C) Curing accelerator>

[0076] The resin composition may contain (C) a curing accelerator as an arbitrary component. Examples of the curing accelerator include phosphorus curing accelerators, amine curing accelerators, imidazole curing accelerators, guanidine curing accelerators, and metal curing accelerators, preferably amine curing accelerators and imidazole curing accelerators, and more preferably imidazole curing accelerators. One curing accelerator may be used alone, or two or more may be used in combination.

[0077] Examples of the phosphorus-based curing accelerator include triphenylphosphine, phosphonium borate compounds, tetraphenylphosphonium tetraphenylborate, n-butylphosphonium tetraphenylborate, tetrabutylphosphonium decanoate, (4-methylphenyl)triphenylphosphonium thiocyanate, tetraphenylphosphonium thiocyanate, and butyltriphenylphosphonium thiocyanate, and triphenylphosphonium thiocyanate is preferred.

[0078] Examples of the amine-based curing accelerator include trialkylamines such as triethylamine and tributylamine, 4-dimethylaminopyridine, benzyldimethylamine, 2,4,6-tris(dimethylaminomethyl)phenol, and 1,8-diazabicyclo(5,4,0)-undecene, and 4-dimethylaminopyridine and 1,8-diazabicyclo(5,4,0)-undecene are preferred.

[0079] Examples of the imidazole curing accelerator include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-undecylimidazole trimellitate, 1-cyanoethyl-2-phenylimidazole trimellitate, 2,4-diamino-6-[2′-methylimidazolyl-(1′)]-ethyl-s-triazine, 2,4- Imidazole compounds such as 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-phenyl-4,5-dihydroxymethylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, 2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole, 1-dodecyl-2-methyl-3-benzylimidazolium chloride, 2-methylimidazoline, 2-phenylimidazoline, and adducts of imidazole compounds with epoxy resins, preferably 2-ethyl-4-methylimidazole and 1-benzyl-2-phenylimidazole.

[0080] As the imidazole-based curing accelerator, a commercially available item may be used, and examples thereof include "P200-H50" manufactured by Mitsubishi Chemical Corporation.

[0081] Examples of the guanidine-based curing accelerator include dicyandiamide, 1-methylguanidine, 1-ethylguanidine, 1-cyclohexylguanidine, 1-phenylguanidine, 1-(o-tolyl)guanidine, dimethylguanidine, diphenylguanidine, trimethylguanidine, tetramethylguanidine, pentamethylguanidine, 1,5,7-triazabicyclo[4.4.0]dec-5-ene, 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-methylbiguanidine, 1-ethylbiguanidine, 1-n-butylbiguanidine, 1-n-octadecylbiguanidine, 1,1-dimethylbiguanidine, 1,1-diethylbiguanidine, 1-cyclohexylbiguanidine, 1-allylbiguanidine, 1-phenylbiguanidine, and 1-(o-tolyl)biguanidine. Preferred examples include dicyandiamide and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0082] As metal curing accelerators, organic metal complexes or organic metal salts of metals such as cobalt, copper, zinc, iron, nickel, manganese, and tin can be cited. As specific examples of organic metal complexes, organic cobalt complexes such as cobalt acetylacetonate (II), cobalt acetylacetonate (III), organic copper complexes such as copper acetylacetonate (II), organic zinc complexes such as zinc acetylacetonate (II), organic iron complexes such as iron acetylacetonate (III), organic nickel complexes such as nickel acetylacetonate (II), and organic manganese complexes such as manganese acetylacetonate (II) can be cited. As organic metal salts, for example, zinc octoate, tin octoate, zinc naphthenate, cobalt naphthenate, tin stearate, zinc stearate, etc. can be cited.

[0083] When the non-volatile component in the resin composition is set to 100% by mass, the content of the (C) curing accelerator is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, particularly preferably 0.03% by mass or more, and is preferably 3% by mass or less, more preferably 1% by mass or less, and particularly preferably 0.5% by mass or less.

[0084] <(D) Thermoplastic resin>

[0085] The resin composition may contain (D) a thermoplastic resin as an arbitrary component. Examples of the thermoplastic resin (D) include phenoxy resins, polyvinyl acetal resins, polyolefin resins, polyimide resins, polyamide-imide resins, polyetherimide resins, polysulfone resins, polyethersulfone resins, polyphenylene ether resins, polyetheretherketone resins, and polyester resins, and phenoxy resins are preferred. The thermoplastic resins may be used alone or in combination of two or more.

[0086] The weight average molecular weight of the thermoplastic resin (D) in terms of polystyrene is preferably 38,000 or more, more preferably 40,000 or more, and further preferably 42,000 or more. The upper limit is preferably 100,000 or less, more preferably 70,000 or less, and further preferably 60,000 or less. The weight average molecular weight of the thermoplastic resin (D) in terms of polystyrene can be measured by gel permeation chromatography (GPC). Specifically, the weight average molecular weight of the thermoplastic resin (D) in terms of polystyrene can be calculated as follows: using LC-9A / RID-6A manufactured by Shimadzu Corporation as a measuring device, using Shodex K-800P / K-804L / K-804L manufactured by Showa Denko K.K. as a column, using chloroform or the like as a mobile phase, measuring at a column temperature of 40°C, and calculating using a standard curve of standard polystyrene.

[0087] As phenoxy resin, for example, phenoxy resin having one or more skeletons selected from bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenol acetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton can be mentioned. The terminal of phenoxy resin can be any functional group such as phenolic hydroxyl group and epoxy group. Phenoxy resin can be used alone or in combination of two or more. Specific examples of phenoxy resins include "1256" and "4250" (both are phenoxy resins containing a bisphenol A skeleton), "YX8100" (a phenoxy resin containing a bisphenol S skeleton), and "YX6954" (a phenoxy resin containing a bisphenol acetophenone skeleton) manufactured by Mitsubishi Chemical Corporation. In addition, "FX280" and "FX293" manufactured by Nippon Steel Chemical Materials Co., Ltd., "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290" and "YL7482" manufactured by Mitsubishi Chemical Corporation can also be mentioned.

[0088] Examples of the polyvinyl acetal resin include polyvinyl formal resin and polyvinyl butyral resin, and polyvinyl butyral resin is preferred. Specific examples of the polyvinyl acetal resin include "Denka Butyral 4000-2", "Denka Butyral 5000-A", "Denka Butyral 6000-C", and "Denka Butyral 6000-EP" manufactured by Denki Kagaku Kogyo Co., Ltd., and S-LEC BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series manufactured by Sekisui Chemical Co., Ltd.

[0089] Specific examples of the polyimide resin include "RIKACOAT SN20" and "RIKACOAT PN20" manufactured by Shin Nippon Rika Co., Ltd.

[0090] Specific examples of polyamide-imide resins include "VYLOMAX HR11NN" and "VYLOMAX HR16NN" manufactured by Toyobo Co., Ltd. Specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polyamide-imide containing a polysiloxane skeleton) manufactured by Hitachi Chemical Co., Ltd.

[0091] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd., etc. Specific examples of polyphenylene ether resins include "OPE-2St1200" manufactured by Mitsubishi Gas Chemical Co., Ltd., etc. Specific examples of polyetheretherketone resins include "SUMIPLOY K" manufactured by Sumitomo Chemical Co., Ltd., etc. Specific examples of polyetherimide resins include "ULTEM" manufactured by GE, etc.

[0092] Specific examples of the polysulfone resin include polysulfone "P1700" and "P3500" manufactured by Solvay Advanced Polymers.

[0093] Examples of the polyolefin resin include ethylene copolymer resins such as low-density polyethylene, ultra-low-density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymers, ethylene-ethyl acrylate copolymers, and ethylene-methyl acrylate copolymers; and polyolefin elastomers such as polypropylene and ethylene-propylene block copolymers.

[0094] Examples of the polyester resin include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, and polycyclohexane dimethyl terephthalate resin.

[0095] Among them, as (D) thermoplastic resin, phenoxy resin and polyvinyl acetal resin are preferred. Therefore, in a preferred embodiment, the thermoplastic resin includes one or more selected from phenoxy resin and polyvinyl acetal resin. Among them, as the thermoplastic resin, phenoxy resin is preferred, and phenoxy resin with a weight average molecular weight of 40,000 or more is particularly preferred.

[0096] When the non-volatile component in the resin composition is set to 100% by mass, the content of the (D) thermoplastic resin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and further preferably 0.5% by mass or more. The upper limit is preferably 5% by mass or less, more preferably 4% by mass or less, and further preferably 3% by mass or less.

[0097] <(E) Amphiphilic polyether block copolymer>

[0098] The resin composition may contain (E) an amphiphilic polyether block copolymer. In the present application, the so-called amphiphilic polyether block copolymer refers to a block copolymer comprising at least one epoxy resin miscible polyether block segment (polyether block segment miscible with epoxy resin) and at least one epoxy resin immiscible polyether block segment (polyether block segment immiscible with epoxy resin). By containing (E) component in the resin composition, the toughness of the resin composition can be improved, the stress relaxation performance can be improved, and thus, the warpage of the cured product of the resin composition can be reduced.

[0099] As the epoxy resin miscible polyether block segment, for example, an epoxy resin miscible polyether block segment derived from alkylene oxide can be cited. As the epoxy resin miscible polyether block segment derived from alkylene oxide, for example, it is preferred to include one or more polyalkylene oxide blocks selected from polyethylene oxide blocks, polypropylene oxide blocks, poly(ethylene oxide-co-propylene oxide) blocks, poly(ethylene oxide-ran-propylene oxide) blocks, and mixtures thereof, and polyethylene oxide blocks are more preferred.

[0100] Examples of the epoxy resin immiscible block segment include at least one epoxy resin immiscible polyether block segment derived from an alkylene oxide, etc. The at least one epoxy resin immiscible polyether block segment derived from an alkylene oxide is preferably, for example, one or more polyalkylene oxides selected from polybutylene oxide blocks, polyhexylene oxide blocks derived from 1,2-epoxyhexane, polydodecane oxide blocks derived from 1,2-epoxydodecane, and mixtures thereof, and more preferably polybutylene oxide blocks.

[0101] The amphiphilic polyether block copolymer preferably has more than one epoxy resin miscible block segment, and more preferably has more than two epoxy resin miscible block segments. Similarly, it is preferred to have more than one epoxy resin immiscible block segment, and more preferably has more than two epoxy resin immiscible block segments. Therefore, for (E) component, for example, it is preferred to have epoxy resin miscible block segments or epoxy resin immiscible block segments selected from diblock, linear triblock, linear tetrablock, high-order multiblock structure, branched block structure, star block structure, and combinations thereof.

[0102] The amphiphilic polyether block copolymer may contain other segments in the molecule within the range that does not impair its effect. Examples of other segments include polyethylene propylene (PEP), polybutadiene, polyisoprene, polydimethylsiloxane, polybutylene oxide, polyhexylene oxide, polyalkyl methacrylates such as polyethylhexyl methacrylate, and mixtures thereof.

[0103] The number average molecular weight of the amphiphilic polyether block copolymer is preferably 3,000 to 20,000. The number average molecular weight is a weight average molecular weight in terms of polystyrene measured by gel permeation chromatography (GPC).

[0104] As for the amphiphilic polyether block copolymer, for example, poly(ethylene oxide)-b-poly(butylene oxide) (PEO-PBO); poly(ethylene oxide)-b-poly(butylene oxide)-b-poly(ethylene oxide) (PEO-PBO-PEO) and other amphiphilic polyether triblock copolymers can be mentioned. Commercially available amphiphilic block copolymers can also be used. As commercially available products, for example, "Fortegra 100" (PEO-PBO-PEO) manufactured by Dow Chemical Company can be mentioned.

[0105] When the non-volatile component in the resin composition is set to 100% by mass, from the viewpoint of improving fracture properties, the content of the component (E) is preferably 0.3% by mass or more, more preferably 0.4% by mass or more, and further preferably 0.5% by mass or more. The upper limit is not particularly limited, as long as the effect of the present invention can be exerted, and is preferably 15% by mass or less, more preferably 10% by mass or less, and further preferably 5% by mass or less.

[0106] <(F) Elastomer>

[0107] The resin composition may contain (F) an elastomer as an optional component. The (F) component may be used alone or in combination of two or more.

[0108] As component (F), it is preferred that the resin has one or more structures selected from polybutadiene structure, polysiloxane structure, poly(meth)acrylate structure, polyalkylene structure, polyalkyleneoxy structure, polyisoprene structure, polyisobutylene structure, and polycarbonate structure in the molecule, and more preferably has one or more structures selected from polybutadiene structure, poly(meth)acrylate structure, polyalkyleneoxy structure, polyisoprene structure, polyisobutylene structure, or polycarbonate structure, and further preferably has one or more structures selected from polybutadiene structure and polyalkyleneoxy structure, and particularly preferably has a resin with a polybutadiene structure. It should be noted that the so-called "(meth)acrylate" refers to a term including methacrylate and acrylate and combinations thereof. These structures may be contained in the main chain or in the side chain.

[0109] In order to reduce the warpage when the resin composition is cured, the (F) component is preferably a high molecular weight. The number average molecular weight (Mn) of the (F) component is preferably 1000 or more, more preferably 1500 or more, and further preferably 3000 or more and 5000 or more. The upper limit is preferably 1,000,000 or less, and more preferably 900,000 or less. The number average molecular weight (Mn) is the number average molecular weight measured by GPC (gel permeation chromatography) in terms of polystyrene conversion.

[0110] From the viewpoint of reacting with the epoxy resin as the component (A) and curing the resin composition to improve the peel strength, the component (F) preferably has a functional group that can react with the epoxy resin as the component (A). It should be noted that the functional group that can react with the epoxy resin as the component (A) also includes a functional group that appears by heating.

[0111] In a preferred embodiment, the functional group that can react with the epoxy resin as component (A) is one or more functional groups selected from hydroxyl, carboxyl, anhydride, phenolic hydroxyl, epoxy, isocyanate and carbamate. Among them, as the functional group, hydroxyl, anhydride, phenolic hydroxyl, epoxy, isocyanate and carbamate are preferred, hydroxyl, anhydride, phenolic hydroxyl and epoxy are more preferred, and phenolic hydroxyl is particularly preferred. However, when the functional group includes an epoxy, the number average molecular weight (Mn) is preferably 5,000 or more.

[0112] A preferred embodiment of the component (F) is a resin containing a polybutadiene structure, and the polybutadiene structure may be contained in the main chain or in the side chain. It should be noted that a part or all of the polybutadiene structure may be hydrogenated. The resin containing the polybutadiene structure is referred to as a polybutadiene resin.

[0113] Specific examples of the polybutadiene resin include “Ricon 130MA8”, “Ricon 130MA13”, “Ricon 130MA20”, “Ricon 131MA5”, “Ricon 131MA10”, “Ricon 131MA17”, “Ricon 131MA20”, and “Ricon 184MA6” (polybutadiene containing an acid anhydride group) manufactured by Cray Valley Corporation, “GQ-1000” (polybutadiene into which a hydroxyl group or a carboxyl group is introduced), “G-1000”, “G-2000”, and “G-3000” (polybutadiene containing hydroxyl groups at both ends) manufactured by Nippon Soda Co., Ltd., “GI-1000”, “GI-2000”, and “GI-3000” (hydrogenated polybutadiene containing hydroxyl groups at both ends), and “FCA-061L” (hydrogenated polybutadiene skeleton epoxy resin) manufactured by Nagase ChemteX Co., Ltd. As one embodiment, linear polyimide (polyimide described in Japanese Unexamined Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208) with hydroxyl-terminated polybutadiene, diisocyanate compound and tetrabasic acid anhydride as raw materials, butadiene containing phenolic hydroxyl group, etc. can be cited. The content of butadiene structure of the polyimide resin is preferably 60% to 95% by mass, more preferably 75% to 85% by mass. The details of the polyimide resin can be referred to the records of Japanese Unexamined Patent Publication No. 2006-37083 and International Publication No. 2008 / 153208, and the contents are incorporated into this specification.

[0114] The preferred embodiment of the (F) component is a resin containing a poly(meth)acrylate structure. The resin containing a poly(meth)acrylate structure is referred to as a poly(meth)acrylic acid-based resin. Examples of the poly(meth)acrylic acid-based resin include TEISANRESIN manufactured by Nagase ChemteX Co., Ltd., and "ME-2000", "W-116.3", "W-197C", "KG-25", "KG-3000" manufactured by Negami Industries Co., Ltd.

[0115] (F) The preferred embodiment of the component is a resin containing a polycarbonate structure. The resin containing a polycarbonate structure is referred to as a polycarbonate resin. As polycarbonate resins, "T6002", "T6001" (polycarbonate diol) manufactured by Asahi Kasei Chemicals, "C-1090", "C-2090", "C-3090" (polycarbonate diol) manufactured by Kuraray Co., Ltd., etc. can be cited. In addition, linear polyimides made of hydroxyl-terminated polycarbonate, diisocyanate compounds and tetrabasic acid anhydrides can also be used. The content of the carbonate structure of the polyimide resin is preferably 60% to 95% by mass, and more preferably 75% to 85% by mass. The details of the polyimide resin can be referred to the record of International Publication No. 2016 / 129541, which is incorporated into this specification.

[0116] In addition, as another embodiment of the component (F), it is a resin containing a siloxane structure. The resin containing a siloxane structure is referred to as a siloxane resin. As the siloxane resin, for example, "SMP-2006", "SMP-2003PGMEA", "SMP-5005PGMEA" manufactured by Shin-Etsu Silicone Co., Ltd., linear polyimide (International Publication No. 2010 / 053185, Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.) made of amino-terminated polysiloxane and tetrabasic acid anhydride can be cited.

[0117] As another embodiment of the (F) component, it is a resin containing an alkylene structure and an alkyleneoxy structure. The resin containing an alkylene structure is called an alkylene resin, and the resin containing an alkyleneoxy structure is called an alkyleneoxy resin. The polyalkyleneoxy structure is preferably a polyalkyleneoxy structure having 2 to 15 carbon atoms, more preferably a polyalkyleneoxy structure having 3 to 10 carbon atoms, and further preferably a polyalkyleneoxy structure having 5 to 6 carbon atoms. Specific examples of alkylene resins and alkyleneoxy resins include "PTXG-1000" and "PTXG-1800" manufactured by Asahi Kasei Fibers Corporation.

[0118] Another embodiment of the component (F) is a resin containing an isoprene structure. A resin containing an isoprene structure is referred to as an isoprene resin. Specific examples of the isoprene resin include "KL-610" and "KL613" manufactured by Kuraray Co., Ltd.

[0119] Another embodiment of the component (F) is a resin containing an isobutylene structure. A resin containing an isobutylene structure is referred to as an isobutylene resin. Specific examples of the isobutylene resin include "SIBSTAR-073T" (styrene-isobutylene-styrene triblock copolymer) and "SIBSTAR-042D" (styrene-isobutylene diblock copolymer) manufactured by Kaneka Corporation.

[0120] When the nonvolatile component in the resin composition is set to 100% by mass, the content of the (F) elastomer is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and further preferably 0.5% by mass or more. The upper limit is preferably 5% by mass or less, more preferably 3% by mass or less, and further preferably 1% by mass or less.

[0121] <(G) Other additives>

[0122] In addition to the above-mentioned components, the resin composition may further include other additives as arbitrary components. Such additives include, for example, flame retardants; organic fillers such as rubber particles; organic metal compounds such as organic copper compounds, organic zinc compounds, and organic cobalt compounds; thickeners; defoamers; leveling agents; adhesion-imparting agents; colorants; and resin additives such as pigments. These additives may be used alone or in combination of two or more in any ratio. The content of each may be appropriately set by a person skilled in the art.

[0123] The method for preparing the resin composition is not particularly limited, and examples thereof include a method in which the components are mixed and dispersed using a rotary mixer or the like (a solvent is added as necessary).

[0124] [Resin sheet]

[0125] The resin sheet of the present invention comprises: a first support, and a resin composition layer bonded to the first support in a releasable manner. Usually, the first support is directly bonded to the resin composition layer. The bonding method of the two components is "direct", which means that there is no other layer between the two bonded components. The thickness of the resin composition layer is 60 μm or more, and the ratio L of one or more in-plane directions of the first support is A / L B The relationship of 1.005 or more and 1.2 or less is satisfied. The in-plane direction of the first support body refers to a direction perpendicular to the thickness direction of the first support body. A represents the length of the first support in the aforementioned in-plane direction when bonded to the resin composition layer. BIt represents the length of the first support body in the aforementioned in-plane direction after peeling off from the resin composition layer. By using such a resin sheet, even if the thickness of the resin composition layer is thick, the appearance of the resin composition layer can be suppressed. In addition, by using the resin sheet of the present invention, the generation of curling can usually be suppressed.

[0126] like Figure 1 As shown in the example of FIG. 1 , the resin sheet 1 of the present invention includes a first support 3 and a resin composition layer 2. Figure 2 As shown in the example of FIG, the resin sheet of the present invention may sequentially include a first support 3, a resin composition layer 2, and a second support 4. The first support 3 and the second support 4 may be formed of the same material or different materials. Usually, the first support functions as a protective film.

[0127] The inventors infer that the structure (mechanism) that can obtain the effect of the present invention is as follows. However, the technical scope of the present invention is not limited to the following structure. As mentioned above, if the thickness of the resin composition layer is thick, the wrinkles generated on the support will be easily transferred to the resin composition layer, which sometimes causes the poor appearance of the resin composition layer. For example, when the support is bonded to the resin composition layer, usually, a suitable bonding tension is applied to the support to bond. In this way, a stress corresponding to the aforementioned tension remains in the support. If wrinkles are generated on the support due to the aforementioned stress when the resin sheet is stored, the wrinkles can be transferred to the resin composition layer, which may produce a poor appearance. The resin sheet is mostly stored in a state of being wound into a roll, and when stored in the roll, the formation of wrinkles and poor appearance is particularly significant. In addition, it is believed that if the thickness of the resin composition layer is thick, stress is applied, and due to the stress, the wrinkles generated on the support will be easily transferred to the resin composition layer.

[0128] In the resin sheet of the present invention, the length L of the first support when joined to the resin composition layer in one or more in-plane directions is A , and the length L of the first support after the first support is peeled off from the resin composition layer B That is, the first support of the resin sheet of the present invention has at least one ratio L A / L B The in-plane direction that satisfies a certain relationship. Length L A The length L represents the length of the first support body under tension. B = represents the length of the first support body in the state where the tension is released (from the state where the tension is released), so the aforementioned ratio L A / L B represents the degree of elongation of the first support body due to tension. Therefore, the aforementioned ratio L A / L B Indirectly indicates the magnitude of the tension applied to the first support in the state of bonding with the resin composition layer. A / L B Satisfying a specific relationship means that a specific range of tension that can suppress wrinkles during storage is applied to the first support. Thus, even if the thickness of the resin composition layer is thick, wrinkles can be suppressed from being transferred to the resin composition layer. In addition, by using the resin sheet of the present invention, the generation of curling can usually be suppressed.

[0129] <Resin composition layer>

[0130] The resin composition layer is a layer containing the resin composition of the present invention, and is usually formed of the resin composition. The resin composition is as described above.

[0131] From the viewpoint of sealing electronic components, the thickness of the resin composition layer is more than 60 μm, preferably more than 80 μm, more preferably more than 100 μm, and further preferably more than 150 μm. In addition, generally, there is a tendency that the thicker the thickness of the resin composition layer, the easier it is to produce a poor appearance. Therefore, the thickness of the aforementioned range represents the thickness of the resin composition layer that produces a problem (topic) such as a poor appearance. From the viewpoint that the resin composition layer with such a thickness can suppress the poor appearance, the resin sheet of the present invention has technical significance. The upper limit of the thickness of the resin composition layer is not particularly limited, for example, it can be less than 1000 μm, less than 500 μm, less than 300 μm, etc.

[0132] The minimum melt viscosity of the resin composition layer at 60°C to 200°C is preferably 1000 poise or more, more preferably 2000 poise or more, and further preferably 3000 poise or more, 4000 poise or more, or 4500 poise or more. When the minimum melt viscosity is high as described above, the rigidity of the resin composition layer becomes hard, so it is not easy to be transferred from the wrinkles of the first support. On the other hand, the upper limit of the melt viscosity is arbitrary. However, in the past, there was a tendency that the lower the minimum melt viscosity, the easier it was to produce a poor appearance due to the transfer of wrinkles. According to the present invention, even in the case of a resin composition layer that is prone to poor appearance as described above, the poor appearance can be suppressed. Therefore, from the perspective of effectively utilizing the effect of suppressing the poor appearance that was easy to produce in the past as described above, it is preferred that the minimum melt viscosity is low. Specifically, the aforementioned minimum melt viscosity is less than 20,000 poise, more preferably less than 15,000 poise, and further preferably less than 10,000 poise or less, or less than 7,500 poise. The minimum melt viscosity can be measured using a dynamic viscoelasticity measuring device. The aforementioned minimum melt viscosity can be measured by the method described in the examples described later.

[0133] As described above, the thicker the resin composition layer, the easier it is to produce poor appearance. In addition, the lower the minimum melt viscosity of the resin composition layer, the easier it is to produce. Therefore, from the perspective of effectively utilizing the effect of suppressing poor appearance, the thickness and minimum melt viscosity of the resin composition layer preferably satisfy the specific relationship that is particularly prone to poor appearance in the past. Specifically, when the minimum melt viscosity of the resin composition layer at 60°C to 200°C is set to M (poise) and the thickness of the resin composition layer is set to T (μm), M / T is preferably 5 or more, more preferably 10 or more, more preferably 15 or more, preferably 200 or less, more preferably 190 or less, and more preferably 180 or less.

[0134] <First support>

[0135] Examples of the first support include films made of a plastic material and release paper, and films made of a plastic material are preferred.

[0136] When a film formed of a plastic material is used as the first support, the plastic material includes polyesters such as polyethylene terephthalate (hereinafter sometimes referred to as "PET") and polyethylene naphthalate (hereinafter sometimes referred to as "PEN"); polyolefins such as low-density polyethylene and unstretched polypropylene; polycarbonate (hereinafter sometimes referred to as "PC"); acrylic polymers such as polymethyl methacrylate (hereinafter sometimes referred to as "PMMA"); cyclic polyolefins; triacetyl cellulose (hereinafter sometimes referred to as "TAC"); polyether sulfide (hereinafter sometimes referred to as "PES"); polyether ketone; polyimide; polyvinyl chloride; etc. Among them, polyethylene terephthalate, polyethylene naphthalate, polyolefins, and vinyl chloride are preferred, and polyolefins and vinyl chloride are particularly preferred.

[0137] As the first support, a commercially available product can be used, such as "GF-1" manufactured by Tamapoly Co., Ltd., "TORAYFAN NO9405S" manufactured by Toray Film Processing Co., Ltd., "Type C+" manufactured by Achilles Co., Ltd., and the like.

[0138] The surface of the first support that is in contact with the resin composition layer may be subjected to treatment such as matte treatment, corona treatment, and antistatic treatment.

[0139] In addition, as the first support, a support with a release layer having a release layer on the surface bonded to the resin composition layer can be used. As a release agent used in the release layer of the support with a release layer, for example, one or more release agents selected from alkyd resins, polyolefin resins, polyurethane resins, and silicone resins can be mentioned. Commercially available products of release agents include, for example, "SK-1", "AL-5", "AL-7" manufactured by Lintec Co., Ltd., which are alkyd resin-based release agents. In addition, as a support with a release layer, for example, "Lumirror T60" manufactured by Toray Industries, Inc.; "Purex" manufactured by Teijin Limited; "Unipeel" manufactured by UNITIKA Co., Ltd.; and the like can be mentioned.

[0140] In one or more in-plane directions of the first support, L A / L B is 1.005 or more, preferably 1.01 or more, more preferably 1.05 or more, and further preferably 1.08 or more. A / L B The lower limit of L is within the above range, which can inhibit the generation of wrinkles. A / L B The upper limit of L is 1.2 or less, preferably 1.18 or less, more preferably 1.17 or less, and further preferably 1.15 or less. A / L B When the upper limit value of is within the above range, the handling properties as a resin sheet can be further improved.

[0141] The length L of the first support A and L B The length L of the first support can be measured by the following method. A The measurement can be performed under the conditions of a temperature of 23°C and a humidity of 70%. B For example, the first support can be pulled and peeled off with a force of 0.008 kgf / cm in the thickness direction using a Tensilon universal material testing machine at a temperature of 23°C and a humidity of 70%, and then measured at the aforementioned temperature and humidity.

[0142] Ratio L A / L B The number of in-plane directions of the first support satisfying the above-mentioned specific relationship may be 1 or may be 2 or more. When the resin sheet has a long strip shape that can be wound into a roll, the first support preferably has a ratio L satisfying the above-mentioned specific relationship in the in-plane direction parallel to the longitudinal direction of the resin sheet. A / L BFor the first support body having a long strip shape, the first support body is usually bonded to the resin composition layer under a tension applied in the longitudinal direction. Therefore, in the in-plane direction parallel to the longitudinal direction, the first support body has a ratio L satisfying the above-mentioned specific relationship. A / L B In the case of wrinkles, the tension that may cause wrinkles can be appropriately adjusted to effectively suppress poor appearance.

[0143] The elastic modulus of the first support at 23°C is preferably 2 GPa or less, more preferably 1.8 GPa or less, further preferably 1.6 GPa or less, preferably 0.05 GPa or more, more preferably 0.06 GPa or more, and further preferably 0.07 GPa or more. By making the elastic modulus of the first support within the above range, curling of the resin composition layer can be further suppressed. The elastic modulus can be measured by the method according to ASTM D882.

[0144] The thickness of the first support is preferably in the range of 5 μm to 75 μm, more preferably in the range of 10 μm to 60 μm. When a support with a release layer is used, the thickness of the entire support with a release layer is preferably in the above range.

[0145] <Second Support Body>

[0146] For resin sheets, Figure 2 As shown in the example, in addition to the first support 3 and the resin composition layer 2, a second support 4 may be provided. The first support 3 and the second support 4 may be formed of the same material as described above, or may be formed of different materials. From the viewpoint of suppressing wrinkles of the resin composition layer, it is preferred that they are formed of different materials.

[0147] When the resin sheet has a second support, L of the second support is a / L b It is preferably 0.95 or more, more preferably 0.98 or more, further preferably 1 or more, and is preferably 1.5 or less, more preferably 1.3 or less, further preferably 1.1 or less. a represents the length of the second support in the aforementioned in-plane direction when bonded to the resin composition layer. b The second support has L in the above range. a / L b In the case of the in-plane direction of the second support, the appearance defects of the resin composition layer can be particularly effectively suppressed. a and L bThe length L of the first support can be used A and L B The same method was used to determine.

[0148] The elastic modulus of the second support at 23° C. is preferably within the same range as the elastic modulus of the first support at 23° C. This can further suppress the occurrence of curling in the resin composition layer.

[0149] When the resin sheet has a first support and a second support, the difference between the elastic modulus of the first support at 23°C and the elastic modulus of the second support at 23°C (elastic modulus of the second support - elastic modulus of the first support) is preferably 2 GPa or more, more preferably 2.2 GPa or more, further preferably 2.4 GPa or more, preferably 4 GPa or less, more preferably 3.95 GPa or less, and further preferably 3.9 GPa or less. By making the difference in elastic modulus between the first support and the second support within the above range, curling of the resin composition layer can be further suppressed.

[0150] <Method for producing resin sheet>

[0151] Regarding the resin sheet, for example, it can be manufactured using a method including the following steps: a step of applying the resin composition on an appropriate supporting member such as a second support to form a resin composition layer; and a step of attaching a first support to which tension is applied and bonding the first support to the surface of the resin composition layer that is not bonded to the second support (i.e., the surface on the opposite side of the second support).

[0152] The coating of resin combination can be carried out using coating devices such as die coaters. In addition, for the process forming the resin combination layer, as required, the resin combination can be dissolved in an organic solvent and prepared as resin varnish, and the resin varnish is applied to form the resin combination layer. By using a solvent, the viscosity can be adjusted to improve the coating property. When the resin varnish is used, usually, the resin varnish is dried after coating to form the resin combination layer.

[0153] Examples of the organic solvent include ketone solvents such as acetone, methyl ethyl ketone, and cyclohexanone; acetate solvents such as ethyl acetate, butyl acetate, cellosolve acetate (cellosolve acetate), propylene glycol monomethyl ether acetate, and carbitol acetate; carbitol solvents such as cellosolve and butyl carbitol; aromatic hydrocarbon solvents such as toluene and xylene; amide solvents such as dimethylformamide, dimethylacetamide (DMAc), and N-methylpyrrolidone; etc. The organic solvent may be used alone or in combination of two or more at any ratio.

[0154] Drying can be carried out by known methods such as heating and blowing hot air. As for the drying conditions, the drying is carried out in a manner that the content of the organic solvent in the resin composition layer is generally 10% by mass or less, preferably 5% by mass or less. Although it also varies depending on the boiling point of the organic solvent in the resin varnish, for example, in the case of using a resin varnish containing 30% to 60% by mass of an organic solvent, the resin composition layer can be formed by drying at 50° C. to 150° C. for 3 minutes to 10 minutes.

[0155] After the resin composition layer is formed, the resin composition layer is bonded to the first support to obtain a resin sheet. The bonding is usually performed under a state where appropriate tension is applied to the first support. The tension applied to the first support is the same as the tension applied when bonding the protective film when making the conventional resin sheet.

[0156] In addition, the resin sheet can be stored by being wound into a roll. In this case, the resin sheet is preferably wound so that the first support is located inside the roll.

[0157] <Applications of resin sheets>

[0158] The resin sheet can be suitably used to form an insulating layer in the manufacture of semiconductor chip packaging (insulating resin sheet for semiconductor chip packaging). For example, the resin sheet can be used to form an insulating layer of a circuit substrate (insulating resin sheet for circuit substrate). Examples of packages using such substrates include FC-CSP, MIS-BGA packages, and ETS-BGA packages.

[0159] In addition, the resin sheet can be suitably used to seal the semiconductor chip (resin sheet for semiconductor chip sealing). As applicable semiconductor chip packages, for example, fan-out type WLP (wafer level packaging), fan-in type WLP, fan-out type PLP (panel level packaging), fan-in type PLP, etc. can be cited.

[0160] In addition, the resin sheet can be used as a material for MUF (Mold Underfill) used after the semiconductor chip is connected to the substrate.

[0161] Furthermore, the resin sheet can be used for other wide applications requiring high insulation reliability. For example, the resin sheet can be suitably used to form an insulating layer of a circuit board such as a printed wiring board.

[0162] <Characteristics of resin sheets>

[0163] The resin sheet can obtain a resin composition layer in which wrinkles are suppressed. Therefore, the appearance of the resin composition layer can be suppressed. For the evaluation of wrinkles, for example, the first support body of the resin sheet cut into 50 cm × 50 cm is peeled off, and the resin composition layer is visually observed for the presence or absence of wrinkles. At this time, there are usually no wrinkles in the resin composition layer. The details of the evaluation of wrinkles can be carried out according to the method described in the examples described later.

[0164] The above-mentioned resin sheet can usually obtain a resin composition layer in which curling is suppressed. Therefore, a resin sheet in which warping is suppressed can be provided. For the evaluation of curling, for example, the first support of the resin sheet cut into 50cm×50cm is placed upward on a flat place, and the curling amount of the resin sheet is measured. In this case, the curling amount is preferably less than 50mm. The lower limit of the curling amount is not particularly limited, and can be 0.01mm or more. The details of the curling evaluation can be carried out according to the method described in the embodiments described later.

[0165] [Circuit board]

[0166] The circuit board of the present invention comprises an insulating layer formed from a cured product of the resin composition of the present invention. The circuit board can be produced, for example, by a production method comprising the following steps (1) and (2):

[0167] (1) forming a resin composition layer on a substrate;

[0168] (2) A step of thermally curing the resin composition layer to form an insulating layer.

[0169] In step (1), a substrate is prepared. As the substrate, for example, a glass epoxy substrate, a metal substrate (stainless steel, cold-rolled steel sheet (SPCC) etc.), a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate and the like can be cited. In addition, as a part of the substrate, a metal layer such as copper foil can be provided on the surface. For example, a substrate having a peelable first metal layer and a second metal layer on both surfaces can be used. When such a substrate is used, usually, a conductor layer as a wiring layer that can function as circuit wiring can be formed on the surface of the second metal layer on the opposite side of the first metal layer. As the material of the metal layer, copper foil, copper foil with a carrier, the material of the conductor layer described later, etc. can be cited, preferably copper foil. In addition, as such a substrate having a metal layer, a commercially available product can be used, for example, an ultra-thin copper foil "Micro Thin" with a carrier copper foil manufactured by Mitsui Mining & Smelting Co., Ltd. can be cited.

[0170] In addition, a conductor layer may be formed on one or both surfaces of the substrate. In the following description, a member including a substrate and a conductor layer formed on the surface of the substrate is sometimes appropriately referred to as a "substrate with a wiring layer". As the conductor material contained in the conductor layer, for example, a material containing one or more metals selected from gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin and indium can be cited. As the conductor material, a single metal can be used, and an alloy can also be used. As the alloy, for example, an alloy of two or more metals selected from the above metals (for example, nickel-chromium alloy, copper-nickel alloy and copper-titanium alloy) can be cited. Among them, from the perspective of versatility, cost and ease of patterning of the conductor layer formation, chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper as a single metal is preferred; and alloys of nickel-chromium alloy, copper-nickel alloy and copper-titanium alloy as an alloy. Among them, single metals of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver or copper are more preferred; and nickel-chromium alloy, and single metal of copper is particularly preferred.

[0171] For the conductor layer, for example, in order to make it function as a wiring layer, pattern processing can be performed. At this time, the ratio of the line width (circuit width) / line spacing (width between circuits) of the conductor layer is not particularly limited, preferably 20 / 20μm or less (i.e., the pitch is 40μm or less), more preferably 10 / 10μm or less, further preferably 5 / 5μm or less, further preferably 1 / 1μm or less, and particularly preferably 0.5 / 0.5μm or more. The spacing does not need to be the same throughout the entire range of the conductor layer. The minimum spacing of the conductor layer can be, for example, 40μm or less, 36μm or less, or 30μm or less.

[0172] The thickness of the conductor layer depends on the design of the circuit board, but is preferably 3 μm to 35 μm, more preferably 5 μm to 30 μm, further preferably 10 μm to 20 μm, and particularly preferably 15 μm to 20 μm.

[0173] The conductor layer can be formed, for example, by a method including the following steps: a step of laminating a dry film (photosensitive resist film) on a substrate; a step of exposing and developing the dry film under prescribed conditions using a photomask to form a pattern, thereby obtaining a pattern dry film; a step of forming a conductor layer by a plating method such as an electrolytic plating method using the developed pattern dry film as a plating mask; and a step of stripping the pattern dry film. As the dry film, a photosensitive dry film formed from a photoresist composition can be used, for example, a dry film formed from a resin such as a novolac resin or an acrylic resin can be used. The lamination conditions of the substrate and the dry film can be the same as the lamination conditions of the substrate and the resin sheet described later. Regarding the stripping of the dry film, for example, an alkaline stripping solution such as a sodium hydroxide solution can be used.

[0174] After preparing the substrate, the resin composition layer is formed on the substrate. When a conductor layer is formed on the surface of the substrate, the resin composition layer is preferably formed so that the conductor layer is buried in the resin composition layer.

[0175] The formation of the resin composition layer can be carried out, for example, by laminating a resin sheet with a substrate. About this lamination, for example, by heating and pressing the resin sheet on the substrate, the resin composition layer is attached to the substrate to carry out. As a component (hereinafter sometimes referred to as "heating and pressing component") for heating and pressing the resin sheet on the substrate, for example, a heated metal plate (SUS end plate, etc.) or a metal roller (SUS roller, etc.) can be cited. It should be noted that it is preferred that the heating and pressing component is not directly pressed to the resin sheet, but is pressed across an elastic material such as heat-resistant rubber so that the resin sheet fully follows the surface unevenness of the substrate.

[0176] The lamination of the substrate and the resin sheet can be implemented, for example, by vacuum lamination. In the vacuum lamination method, the heating and pressing temperature is preferably 60°C to 160°C, and more preferably in the range of 80°C to 140°C. The heating and pressing pressure is preferably 0.098MPa to 1.77MPa, and more preferably in the range of 0.29MPa to 1.47MPa. The heating and pressing time is preferably 20 seconds to 400 seconds, and more preferably in the range of 30 seconds to 300 seconds. The lamination is preferably implemented under reduced pressure conditions with a pressure of 13hPa or less.

[0177] After lamination, the laminated resin sheets can be smoothed by, for example, pressing the heating and pressing member under normal pressure (atmospheric pressure). The pressing conditions for the smoothing treatment can be set to the same conditions as the heating and pressing conditions for the above-mentioned lamination. It should be noted that lamination and smoothing treatment can be performed continuously using a vacuum laminator.

[0178] In addition, the formation of the resin composition layer can be carried out, for example, by compression molding. For the specific operation of the compression molding method, for example, an upper mold and a lower mold are prepared as a mold. The resin composition is applied to a substrate. The substrate coated with the resin composition is installed in the lower mold. Then, the upper mold and the lower mold are molded together, and heat and pressure are applied to the resin composition to perform compression molding.

[0179] In addition, the specific operation of the compression molding method can be carried out as described below. As a mold for compression molding, an upper mold and a lower mold are prepared. The resin composition is loaded on the lower mold. In addition, a substrate is installed on the upper mold. Then, the upper mold and the lower mold are molded in a manner that the resin composition loaded on the lower mold contacts the substrate installed on the upper mold, and heat and pressure are applied to perform compression molding.

[0180] The molding conditions in the compression molding method vary according to the composition of the resin composition. The temperature of the mold during molding is preferably a temperature at which the resin composition can exert excellent compression moldability, for example, preferably 80°C or more, more preferably 100°C or more, more preferably 120°C or more, preferably 200°C or less, more preferably 170°C or less, and more preferably 150°C or less. In addition, the pressure applied during molding is preferably 1MPa or more, more preferably 3MPa or more, more preferably 5MPa or more, preferably 50MPa or less, more preferably 30MPa or less, and more preferably 20MPa or less. The cure time is preferably 1 minute or more, more preferably 2 minutes or more, particularly preferably 5 minutes or more, preferably 60 minutes or less, more preferably 30 minutes or less, and particularly preferably 20 minutes or less. Typically, after forming the resin composition layer, the mold is disassembled. The disassembly of the mold can be performed before the thermal curing of the resin composition layer, or after the thermal curing.

[0181] After forming the resin composition layer on the substrate, the resin composition layer is thermally cured to form an insulating layer. The thermal curing conditions of the resin composition layer vary depending on the type of the resin composition, and the curing temperature is generally in the range of 120° C. to 240° C. (preferably in the range of 150° C. to 220° C., more preferably in the range of 170° C. to 200° C.), and the curing time is in the range of 5 minutes to 120 minutes (preferably 10 minutes to 100 minutes, more preferably 15 minutes to 90 minutes).

[0182] Before the resin composition layer is thermally cured, the resin composition layer may be subjected to a preheating treatment of heating at a temperature lower than the curing temperature. For example, before the resin composition layer is thermally cured, the resin composition layer may be preheated at a temperature of 50° C. or more and less than 120° C. (preferably 60° C. or more and 110° C. or less, more preferably 70° C. or more and 100° C. or less) for usually 5 minutes or more (preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes).

[0183] By operating as described above, a circuit substrate with an insulating layer can be manufactured. In addition, the manufacturing method of the circuit substrate can further include any steps. For example, when a resin sheet is used to manufacture the circuit substrate, the manufacturing method of the circuit substrate can include a step of peeling off the first support and the second support of the resin sheet. The first support and the second support can be peeled off before the thermal curing of the resin composition layer, or can be peeled off after the thermal curing of the resin composition layer.

[0184] For the manufacturing method of the circuit substrate, for example, after forming the insulating layer, a process of grinding the surface of the insulating layer may be included. The grinding method is not particularly limited. For example, a surface grinder may be used to grind the surface of the insulating layer.

[0185] The method for manufacturing a circuit substrate may include, for example, a step (3) of connecting the conductor layer between layers, and a step of opening holes in the insulating layer. Thus, holes such as via holes and through holes may be formed on the insulating layer. Examples of methods for forming via holes include laser irradiation, etching, and mechanical drilling. The size and shape of the via holes may be appropriately determined according to the design of the circuit substrate. It should be noted that step (3) may be performed by grinding or polishing the insulating layer to connect between layers.

[0186] After forming the through hole, it is preferred to perform a process of removing the smear in the through hole. This process is sometimes also referred to as a desmear process. For example, in the case where the conductor layer is formed on the insulating layer by a plating process, the through hole can be subjected to a wet desmear process. In addition, in the case where the conductor layer is formed on the insulating layer by a sputtering process, a dry desmear process such as a plasma treatment process can be performed. Furthermore, the desmear process can be used to roughen the insulating layer.

[0187] In addition, the insulating layer may be subjected to a roughening treatment before the conductor layer is formed on the insulating layer. By this roughening treatment, the surface of the insulating layer including the inside of the through hole can be generally roughened. As the roughening treatment, any of dry and wet roughening treatments can be performed. As an example of dry roughening treatment, plasma treatment and the like can be cited. In addition, as an example of wet roughening treatment, a method of sequentially performing swelling treatment using a swelling solution, roughening treatment using an oxidant, and neutralization treatment using a neutralizing solution can be cited.

[0188] After the through hole is formed, a conductor layer is formed on the insulating layer. By forming a conductor layer at the position where the through hole is formed, the newly formed conductor layer is connected to the conductor layer on the surface of the substrate, and interlayer connection can be performed. Regarding the method for forming the conductor layer, for example, plating method, sputtering method, evaporation method, etc. can be cited, among which plating method is preferred. In a preferred embodiment, the surface of the insulating layer is plated using an appropriate method such as a semi-additive method and a full-additive method to form a conductor layer with a desired wiring pattern. In addition, when the first support or the second support in the resin sheet is a metal foil, a subtractive method can be used to form a conductor layer with a desired wiring pattern. The material of the formed conductor layer can be a single metal or an alloy. In addition, the conductor layer can have a single-layer structure or a multilayer structure including two or more layers of different types of materials.

[0189] Here, an example of an implementation method for forming a conductor layer on an insulating layer is described in detail. A plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, corresponding to the desired wiring pattern, to expose a portion of the plating seed layer. An electrolytic plating layer is formed on the exposed plating seed layer by electrolytic plating, and then the mask pattern is removed. Then, the unnecessary plating seed layer is removed by etching or other treatments, thereby forming a conductor layer with a desired wiring pattern. It should be noted that when forming the conductor layer, the dry film used in the formation of the mask pattern is the same as the above-mentioned dry film.

[0190] The method for manufacturing a circuit board may include a step (4) of removing a substrate. By removing the substrate, a circuit board having an insulating layer and a conductor layer embedded in the insulating layer can be obtained. This step (4) can be performed, for example, when a substrate having a strippable metal layer is used.

[0191] [Semiconductor chip packaging]

[0192] A semiconductor chip package according to a first embodiment of the present invention includes: the above-mentioned circuit substrate and a semiconductor chip mounted on the circuit substrate. The semiconductor chip package can be manufactured by bonding the semiconductor chip to the circuit substrate.

[0193] The bonding conditions between the circuit substrate and the semiconductor chip may be any conditions under which the terminal electrodes of the semiconductor chip and the circuit wiring of the circuit substrate can be connected by conductors. For example, the conditions used in flip-chip mounting of the semiconductor chip may be used. In addition, for example, the semiconductor chip and the circuit substrate may be bonded via an insulating adhesive.

[0194] As an example of a joining method, a method of crimping a semiconductor chip to a circuit substrate can be cited. As crimping conditions, the crimping temperature is usually in the range of 120° C. to 240° C. (preferably in the range of 130° C. to 200° C., more preferably in the range of 140° C. to 180° C.), and the crimping time is usually in the range of 1 second to 60 seconds (preferably 5 seconds to 30 seconds).

[0195] Another example of the bonding method is a method of bonding a semiconductor chip to a circuit board by reflow. The reflow conditions may be in the range of 120°C to 300°C.

[0196] After the semiconductor chip is bonded to the circuit board, the semiconductor chip may be filled with a mold underfill material. As the mold underfill material, the above-mentioned resin composition may be used, and the above-mentioned resin sheet may be used.

[0197] The semiconductor chip package according to the second embodiment of the present invention comprises: a semiconductor chip, and a cured product of the resin composition for sealing the semiconductor chip. In such a semiconductor chip package, the cured product of the resin composition generally functions as a sealing layer. As the semiconductor chip package according to the second embodiment, a fan-out WLP can be cited, for example.

[0198] The manufacturing method of the semiconductor chip package such as the fan-out WLP includes the following steps:

[0199] (A) a step of laminating a temporary fixing film on a substrate;

[0200] (B) a step of temporarily fixing the semiconductor chip on the temporary fixing film;

[0201] (C) a step of laminating a resin composition layer of the resin sheet of the present invention on a semiconductor chip, or applying the resin composition of the present invention on a semiconductor chip and thermally curing it to form a sealing layer;

[0202] (D) a step of peeling the substrate and the temporary fixing film from the semiconductor chip;

[0203] (E) a step of forming a rewiring formation layer (insulating layer) on the surface of the semiconductor chip from which the substrate and the temporary fixing film have been peeled off;

[0204] (F) a step of forming a conductor layer (rewiring layer) on the rewiring forming layer (insulating layer); and

[0205] (G) forming a solder resist layer on the conductor layer. In addition, the method for manufacturing a semiconductor chip package may include: (H) cutting a plurality of semiconductor chip packages into individual semiconductor chip packages to separate them into pieces.

[0206] For details of such a method for manufacturing a semiconductor chip package, reference may be made to paragraphs 0066 to 0081 of International Publication No. 2016 / 035577, the contents of which are incorporated into this specification.

[0207] The semiconductor chip package according to the third embodiment of the present invention is, for example, the semiconductor chip package according to the second embodiment, wherein a rewiring forming layer or a solder resist layer is formed using a cured product of the resin composition of the present invention.

[0208] [Semiconductor devices]

[0209] Examples of semiconductor devices that can be installed with the above-mentioned semiconductor chip package include various semiconductor devices that can be used in electrical products (e.g., computers, mobile phones, smart phones, tablet devices, wearable devices, digital cameras, medical equipment, and televisions, etc.) and transportation vehicles (e.g., motorcycles, cars, trams, ships, and airplanes, etc.). Example

[0210] Hereinafter, the present invention will be specifically described by showing the embodiments. However, the present invention is not limited to the following embodiments. In the following description, the "parts" and "%" representing the amount refer to "parts by mass" and "% by mass" respectively, unless otherwise clearly stated. In addition, the operations described below are carried out under normal temperature and pressure unless otherwise clearly stated.

[0211] (Synthesis of synthetic resin A)

[0212] Into a flask equipped with a stirring device, a thermometer and a condenser, 368.41 g of diethylene glycol monoethyl ether acetate (ethyl diglycol acetate) and 368.41 g of Solvesso 150 (aromatic solvent, manufactured by ExxonMobil Corporation) as a solvent, 100.1 g (0.4 mol) of diphenylmethane diisocyanate and 400 g (0.2 mol) of polycarbonate diol (number average molecular weight: about 2000, hydroxyl equivalent: 1000, non-volatile content: 100%, "C-2015N" manufactured by Kuraray Co., Ltd.) were charged, and the mixture was reacted at 70°C for 4 hours. Next, 195.9 g (0.2 mol) of nonylphenol novolac resin (hydroxyl equivalent 229.4 g / eq, average 4.27 functional groups, average calculated molecular weight 979.5 g / mol) and 41.0 g (0.1 mol) of ethylene glycol bis(trimellitate) anhydride were added, and the temperature was raised to 150° C. over 2 hours, and the reaction was carried out for 12 hours. The FT-IR at 2250 cm -1 The disappearance of the NCO peak was confirmed. The disappearance of the NCO peak was considered the end point of the reaction. After the reactants were cooled to room temperature, they were filtered with a 100-mesh filter cloth to obtain a resin having a polycarbonate structure (non-volatile components of 50% by mass). The number average molecular weight of the obtained resin (synthetic resin A) was 6100.

[0213] (Preparation of Silica A)

[0214] KBM-573 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used to measure the average particle size of 3 μm and the specific surface area of ​​4.4 m 2 / g of spherical silica was surface-treated, thereby obtaining spherical silica A.

[0215] (Preparation of Resin Varnish 1)

[0216] 10 parts of an epoxy resin ("ZX1059" manufactured by Nippon Steel & Sumitomo Chemical Co., Ltd., a 1:1 mixture (mass ratio) of a bisphenol A type epoxy resin and a bisphenol F type epoxy resin, epoxy equivalent: 169 g / eq.), 41 parts of a biphenyl type epoxy resin ("NC3000L" manufactured by Nippon Kayaku Co., Ltd., epoxy equivalent: 269 g / eq.), 3 parts of an amphiphilic polyether block copolymer ("Fortegra 100" manufactured by The Dow Chemical Company), and spherical silica (average particle size: 0.5 μm) surface-treated with a phenylaminosilane coupling agent ("KBM573" manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed with a spherical silica (average particle size: 0.5 μm) having an average particle size of 0.5 μm. m, "SO-C2" manufactured by Yaduma Co., Ltd.), 380 parts of phenol novolac resin (phenolic hydroxyl equivalent is 105, "TD2090-60M" manufactured by DIC Corporation, a MEK solution with a solid content of 60% by mass), 8.3 parts, phenoxy resin ("YX7553BH30" manufactured by Mitsubishi Chemical Corporation, a 1:1 solution of cyclohexanone:methyl ethyl ketone (MEK) with a solid content of 30% by mass), 16.6 parts, 30 parts of methyl ethyl ketone, and 0.3 parts of an imidazole-based curing accelerator ("1B2PZ" manufactured by Shikoku Chemical Co., Ltd.) were mixed and uniformly dispersed using a high-speed rotary mixer to prepare a resin varnish 1.

[0217] (Preparation of Resin Varnish 2)

[0218] 2 parts of synthetic resin A, 2 parts of rubber particles ("PARALOID EXL-2655" manufactured by Dow Chemical Company), 3 parts of naphthalene-type epoxy resin ("ESN-475V" manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., epoxy equivalent of about 332 g / eq.), 6 parts of liquid epoxy resin ("ZX1059" manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd., a 1:1 mixture (mass ratio) of bisphenol A-type epoxy resin and bisphenol F-type epoxy resin, epoxy equivalent of 169 g / eq.), and phenol novolac-based epoxy resin containing a triazine skeleton were prepared. 8.3 parts of a curing agent ("LA-7054" manufactured by DIC Corporation, a MEK solution with a hydroxyl equivalent of 125 g / eq. and a non-volatile content of 60%), 125 parts of silica A, 0.1 parts of a curing accelerator (2-phenyl-4-methylimidazole, "2P4MZ" manufactured by Shikoku Chemical Industry Co., Ltd.), 10 parts of methyl ethyl ketone (MEK), and 8 parts of cyclohexanone were mixed and uniformly dispersed using a high-speed rotary mixer to prepare resin varnish 2.

[0219] <Measurement of elastic modulus of support body>

[0220] The support was cut into a dumbbell No. 1 shape to obtain a test piece. The tensile strength of the test piece was measured using a tensile testing machine "RTC-1250A" manufactured by Orientec Co., Ltd. to determine the elastic modulus at 23°C. The measurement was performed in accordance with JIS K7127. This operation was performed three times, and the average value is shown in the following table.

[0221] <Example 1>

[0222] The resin varnish 1 was applied to the release surface of a 38 μm thick PET film (second support, Lintec Corporation, "AL5", elastic modulus at 23°C: 4 GPa) subjected to release treatment using a die coater so that the thickness after drying would be 200 μm. After coating, the film was dried at 75 to 120°C for 12 minutes to form a resin composition layer.

[0223] Next, a first support (low-density polyethylene, manufactured by Tamapoly Co., Ltd., "GF-1", 30 μm thick, elastic modulus of 0.24 GPa at 23° C.) was bonded to the surface of the resin composition layer, and 50 m was wound into a roll with the support facing inside, thereby producing a resin sheet.

[0224] <Example 2>

[0225] In Example 1, the resin varnish 1 was replaced by the resin varnish 2, and the first support (low-density polyethylene, manufactured by Tamapoly Co., Ltd., "GF-1", with an elastic modulus of 0.24 GPa at 23°C) was replaced by the first support (unstretched polypropylene, manufactured by Toray Film Processing Co., Ltd., "TORAYFAN NO9405S", with an elastic modulus of 0.72 GPa at 23°C). Except for the above matters, the same operation as in Example 1 was carried out to prepare a resin sheet.

[0226] <Example 3>

[0227] In Example 1, the first support (low-density polyethylene, manufactured by Tamapoly Co., Ltd., "GF-1", elastic modulus at 23°C: 0.24 GPa) was replaced with a first support (polyvinyl chloride, manufactured by Achilles Co., Ltd., "Type C+", elastic modulus at 23°C: 0.25 GPa), and dried at 75 to 120°C for 14 minutes. Except for the above matters, the same operation as in Example 1 was carried out to prepare a resin sheet.

[0228] <Example 4>

[0229] In Example 1, the resin varnish 1 was replaced with the resin varnish 2, and after the resin varnish 2 was applied, it was dried at 75 to 120° C. for 10 minutes. Except for the above matters, the same operation as in Example 1 was carried out to produce a resin sheet.

[0230] <Comparative Example 1>

[0231] In Example 1, the first support (low-density polyethylene, manufactured by Tamapoly Co., Ltd., "GF-1", elastic modulus at 23°C is 0.24 GPa) was replaced with the first support (polyethylene terephthalate, manufactured by Lintec Co., Ltd., "AL-5", elastic modulus at 23°C is 4 GPa). Drying was performed at 75 to 120°C for 8 minutes. Except for the above matters, the same operation as in Example 1 was carried out to prepare a resin sheet.

[0232] <Comparative Example 2>

[0233] In Example 1, the first support (low-density polyethylene, manufactured by Tamapoly Co., Ltd., "GF-1", elastic modulus at 23°C is 0.24 GPa) was replaced with the first support (biaxially stretched polypropylene, manufactured by Oji F-Tex Co., Ltd., "ALPHAN MA-411", elastic modulus at 23°C is 2 GPa). Drying was performed at 75 to 120°C for 7 minutes. Except for the above matters, the same operation as in Example 1 was carried out to prepare a resin sheet.

[0234] <Measurement of Minimum Melt Viscosity of Resin Composition Layer>

[0235] The minimum melt viscosity was measured for the resin composition layer of the resin sheet using a dynamic viscoelasticity measuring device ("Rheosol-G3000" manufactured by UBM Co., Ltd.). For 1 g of the sample resin composition collected from the resin composition layer, the temperature was raised from a starting temperature of 60°C to 200°C at a temperature increase rate of 5°C / min using a parallel plate having a diameter of 18 mm, and the dynamic viscoelastic modulus was measured under the measurement conditions of a measurement temperature interval of 2.5°C, a vibration frequency of 1 Hz, and a strain of 1 degree, and the minimum melt viscosity (poise) was measured.

[0236] <The length L of the support body A and L B Determination of >

[0237] Take out a 50 cm resin sheet and cut it into 50 cm x 50 cm. Under the conditions of temperature of 23°C and humidity of 70%, measure the length of the first support in the winding direction of the cut resin sheet and refer to it as the length L of the first support. ANext, under the conditions of temperature of 23°C and humidity of 70%, the first support was peeled off by pulling with a force of 0.008 kgf / cm along the thickness direction of the first support using a Tensilon universal material testing machine, and the length of the peeled first support in the winding direction was measured and taken as the length L of the first support. B , find L A / L B The value of .

[0238] <Evaluation of wrinkles>

[0239] Take out a 50 cm resin sheet and cut it into 50 cm × 50 cm. Peel off the first support of the cut resin sheet, and visually check whether there are wrinkles on the resin composition layer. If wrinkles are formed and the appearance is poor, it is recorded as "×"; if there are no wrinkles and the appearance is good, it is recorded as "○".

[0240] <Curly Review>

[0241] Take out a 50 cm resin sheet and cut it into 50 cm x 50 cm. Place the 38 μm thick PET film that has been subjected to demolding treatment on a flat surface facing downward, and check the curling of the resin sheet. The curling amount is recorded as "×" when it is more than 50 mm, and "○" when it is less than 50 mm.

[0242] [Table 1]

[0243] .

[0244] Description of Reference Numerals

[0245] 1. Resin sheet

[0246] 2. Resin composition layer

[0247] 3. First support

[0248] 4. Second support body.

Claims

1. A resin sheet comprising a first support and a resin composition layer bonded to the first support, in, The thickness of the resin composition layer is 60 μm or more, The ratio L of one or more in-plane directions of the support A / L B Satisfying the relationship of 1.005 or more and 1.2 or less, L A represents the length of the first support in the in-plane direction when bonded to the resin composition layer, L B It indicates the length of the first support in the in-plane direction after being peeled from the resin composition layer.

2. The resin sheet according to claim 1, wherein The thickness of the resin composition layer is 150 μm or more.

3. The resin sheet according to claim 1, wherein The thickness of the resin composition layer is 1000 μm or less.

4. The resin sheet according to claim 1, wherein The thickness of the resin composition layer is 300 μm or less.

5. The resin sheet according to claim 1, wherein The L A / L B A relationship of 1.08 or more is satisfied.

6. The resin sheet according to claim 1, wherein The L A / L B Satisfy the relationship below 1.

15.

7. The resin sheet according to claim 1, wherein The resin sheet includes a first support, a resin composition layer, and a second support in this order.

8. The resin sheet according to claim 1, wherein The resin composition forming the resin composition layer contains a curable resin (A).

9. The resin sheet according to claim 8, wherein The curable resin (A) contains an epoxy resin.

10. The resin sheet according to claim 8, wherein The curable resin (A) contains a curing agent.

11. The resin sheet according to claim 9, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the epoxy resin is 1% by mass or more.

12. The resin sheet according to claim 9, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the epoxy resin is 5% by mass or more.

13. The resin sheet according to claim 9, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the epoxy resin is 45% by mass or less.

14. The resin sheet according to claim 9, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the epoxy resin is 35% by mass or less.

15. The resin sheet according to claim 10, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the curing agent is 0.1% by mass or more.

16. The resin sheet according to claim 10, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the curing agent is 1% by mass or more.

17. The resin sheet according to claim 10, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the curing agent is 40% by mass or less.

18. The resin sheet according to claim 10, wherein When the nonvolatile component in the resin composition is 100% by mass, the content of the curing agent is 30% by mass or less.

19. The resin sheet according to claim 1, wherein The minimum melt viscosity of the resin composition layer at 60° C. to 200° C. is 1,000 poise or more and 20,000 poise or less.

20. The resin sheet according to claim 1, wherein The minimum melt viscosity of the resin composition layer at 60° C. to 200° C. is 4500 poise or more and 15000 poise or less.

21. The resin sheet according to claim 1, wherein The minimum melt viscosity of the resin composition layer at 60°C to 200°C is 7500 poise or less.

22. The resin sheet according to claim 1, wherein When the minimum melt viscosity of the resin composition layer at 60° C. to 200° C. is defined as M poise and the thickness of the resin composition layer is defined as T μm, M / T satisfies a relationship of 5 or more and 200 or less.

23. The resin sheet according to claim 22, wherein The M / T satisfies a relationship of 15 or more.

24. The resin sheet according to claim 22, wherein The M / T satisfies a relationship of 180 or less. 25 . A circuit board produced using the resin sheet according to claim 1 , comprising an insulating layer formed of a cured product of a resin composition layer in the resin sheet. 26 . A semiconductor chip package, comprising: the circuit substrate according to claim 25 , and a semiconductor chip mounted on the circuit substrate. 27 . A semiconductor chip package comprising: a semiconductor chip sealed using the resin sheet according to claim 1 , and a cured product of a resin composition layer in the resin sheet.

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