Resin film, printed wiring board, and semiconductor package

Abstract

A resin film is formed from a resin composition containing a curable resin, an elastomer containing a reactive group, and an inorganic filler.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a resin film, a printed wiring board, and a semiconductor package. BACKGROUND

[0002] In electronic components such as printed wiring boards, semiconductor packages, and the like, an insulating material for the purpose of protection and electrical insulation of elements, wiring, and the like is used. As such an insulating material, resin compositions of various forms such as liquid, sheet, and the like have been developed.

[0003] For example, Patent Literature 1 describes a resin film containing a compound having an N-substituted maleimide group as a curable resin.

[0004] PRIOR ART DOCUMENTS

[0005] PATENT LITERATURE

[0006] Patent Literature 1: International Publication No. 2023 / 282313 SUMMARY

[0007] PROBLEMS TO BE SOLVED BY THE INVENTION

[0008] A resin film containing a curable resin is sometimes used in a process of insulating between terminals that electrically connect two members (for example, a substrate and a semiconductor chip disposed on the substrate) disposed in opposition.

[0009] Specifically, a resin film is disposed on a substrate on which a terminal is disposed, and a portion of the resin film opposite to the substrate is deformed in a manner of filling a gap between the terminals. Next, the resin film in a state of filling the gap between the terminals and covering the top of the terminal is cured. Next, the resin film is polished (polishing process), and the top of the terminal covered with the resin film is exposed.

[0010] It is known from the results of research by the present inventors and the like that the conventional resin film has room for improvement in terms of suitability to the polishing process.

[0011] In view of the above, an object of one embodiment of the present disclosure is to provide a resin film excellent in suitability to a polishing process, a printed wiring board obtained using the resin film, and a semiconductor package obtained using the resin film.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] Specific means for solving the above problems include the following modes.

[0014] <1> A resin film formed of a resin composition containing a curable resin, an elastomer, and an inorganic filler, the elastomer containing a reactive group.

[0015] <2> The resin film according to <1>, wherein a storage modulus at 25°C measured in a cured state is less than or equal to 5.5 GPa.

[0016] <3> The resin film according to <1> or <2>, wherein the curable resin comprises a radically polymerizable curable resin.

[0017] <4> The resin film according to any one of <1> to <3>, wherein a content ratio of the inorganic filler is 50 vol% to 70 vol%.

[0018] <5> The resin film according to any one of <1> to <4> for use as a sealing material for a semiconductor package.

[0019] <6> The resin film according to any one of <1> to <4> for use in forming an insulating layer of a printed wiring board.

[0020] <7> A printed wiring board comprising a cured product of the resin film according to any one of <1> to <4>.

[0021] <8> A semiconductor package comprising a cured product of the resin film according to any one of <1> to <4>.

[0022] Effects of Invention

[0023] According to one embodiment of the present disclosure, a resin film excellent in suitability for a polishing treatment, a printed wiring board obtained using the resin film, and a semiconductor package obtained using the resin film are provided. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is a diagram schematically showing an example of a polishing treatment using the resin film of the present disclosure. DETAILED DESCRIPTION

[0025] In the present disclosure, the term "step" includes a step independent of other steps, and even when it cannot be clearly distinguished from other steps, as long as the purpose of the step can be achieved, the step is included.

[0026] In the present disclosure, a numerical range indicated using "~" includes the numerical values written before and after the "~" as the minimum value and the maximum value, respectively.

[0027] In the numerical ranges described in stages in the present disclosure, the upper limit value or the lower limit value described in one numerical range can be replaced with the upper limit value or the lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range can be replaced with the value shown in the examples.

[0028] In the present disclosure, each component can include a plurality of respective substances. In the case where a plurality of substances corresponding to each component is present in a composition, unless otherwise specified, the content or amount of each component refers to the total content or amount of the plurality of substances present in the composition.

[0029] In the present disclosure, "resin composition" refers to a mixture of two or more components containing at least a resin. In the case where the resin composition includes a curable component, a state in which at least a part of the curable component has reacted is also included in the resin composition.

[0030] In the present disclosure, "solid component" refers to a component other than a volatile component such as a solvent.

[0031] In the present disclosure, "(meth)acrylate" refers to "acrylate" or "methacrylate", "(meth)acrylic acid" refers to "acrylic acid" or "methacrylic acid", and "(meth)acryloyl" refers to "acryloyl" or "methacryloyl".

[0032] Regarding the "molecular weight" of a compound in the present disclosure, in the case where the compound is not a polymer and the structural formula of the compound can be determined, it refers to the molecular weight that can be calculated from the structural formula, and in the case where the compound is a polymer, it refers to the number average molecular weight or the weight average molecular weight.

[0033] The mechanism of action described in the present specification is speculative and does not limit the mechanism of exerting the effects of the resin composition of the present embodiment.

[0034] The present embodiment also includes a manner in which the matters described in the present specification are combined arbitrarily.

[0035] <Resin film>

[0036] The resin film of the present disclosure is formed from a resin composition including a curable resin, an elastomer, and an inorganic filler, the elastomer including a reactive group.

[0037] Hereinafter, the elastomer including a reactive group will also be referred to as a "reactive elastomer".

[0038] As shown in the examples described later, the resin film of the present disclosure exhibits excellent suitability to a polishing treatment performed after curing.

[0039] In particular, the resin film of the present disclosure achieves excellent suitability to a polishing treatment by using a reactive elastomer as the elastomer.

[0040] As a means to improve the suitability of the resin film to a polishing treatment, it is also considered not to incorporate an elastomer in the resin film. However, if the elastomer is removed in order to improve the suitability to a polishing treatment, other problems such as an increase in warpage of a substrate to which the resin film is attached can occur.

[0041] The resin film of the present disclosure achieves excellent suitability to polishing treatment even if the resin film contains an elastomer, by using an elastomer containing a reactive group as the elastomer.

[0042] Further, by using an elastomer containing a reactive group as the elastomer, the resin film of the present disclosure can improve the polishing property while maintaining the elastic modulus of the resin film at a low value. That is, the resin film of the present disclosure can balance the opposite characteristics of improving the polishing property and suppressing warpage of a substrate.

[0043] From the viewpoint of suppressing warpage of a substrate to which the resin film is attached, the resin film of the present disclosure preferably has a storage modulus at 25°C in a cured state of less than or equal to 5.5 GPa, more preferably less than or equal to 5.4 GPa, and further preferably less than or equal to 5.3 GPa.

[0044] From the viewpoint of suitability to polishing treatment, the above storage modulus is preferably greater than or equal to 3 GPa, more preferably greater than or equal to 4 GPa, and further preferably greater than or equal to 4.2 GPa.

[0045] In the present disclosure, the above storage modulus is measured by dynamic viscoelasticity measurement (DMA) under the conditions described in the examples.

[0046] The resin film of the present disclosure is formed from a resin composition containing a curable resin, a reactive elastomer, and an inorganic filler.

[0047] Hereinafter, each component that can be contained in the resin composition constituting the resin film of the present disclosure will be described.

[0048] (Curable resin)

[0049] The resin composition contains a curable resin.

[0050] In the present disclosure, the curable resin refers to a resin that exhibits a property of curing by a treatment such as heating, active ray irradiation, or the like.

[0051] As the curable resin that can be contained in the resin composition, a compound having an N-substituted maleimide group, a vinyl group, a (meth)acryloyl group, an epoxy group, a hydroxyl group, a carboxyl group, an amino group, or the like as a reactive group can be exemplified.

[0052] From the viewpoint of suitability to the manufacturing process of electronic components, heat resistance, and the like, the curable resin is preferably a thermosetting resin that exhibits a property of curing by heating.

[0053] The curable resin can be used alone or in combination of two or more.

[0054] From the viewpoint of the handleability of the resin film, it is preferred that at least one of the curable resins contained in the resin composition be solid at 25°C, and more preferably that at least one of the curable resins contained in the resin composition be solid at 25°C and at least one be liquid at 25°C.

[0055] The curable resin contained in the resin composition can be radical polymerizable.

[0056] The resin composition containing a radical polymerizable curable resin is, for example, less likely to change in properties upon storage as compared with a resin composition containing an epoxy resin. Thus, for example, it has advantages such as being able to be stored at ordinary temperature.

[0057] Among the radical polymerizable curable resins, a maleimide resin is preferred from the viewpoint of heat resistance and dielectric properties (low dielectric constant).

[0058] In the present disclosure, a maleimide resin refers to a compound having an N-substituted maleimide group as a reactive group.

[0059] From the viewpoint of curability, the maleimide resin is preferably a compound having two N-substituted maleimide groups (hereinafter, also referred to as a bismaleimide resin) or a compound having three or more N-substituted maleimide groups (hereinafter, also referred to as a polymaleimide resin).

[0060] From the viewpoint of heat resistance, the maleimide resin is preferably a compound having an N-substituted maleimide group directly bonded to an aromatic ring (hereinafter, also referred to as an aromatic maleimide resin), and more preferably a compound having two or more N-substituted maleimide groups directly bonded to an aromatic ring (hereinafter, also referred to as an aromatic bismaleimide resin or an aromatic polymaleimide resin).

[0061] The maleimide resin contained in the resin composition can be only one, or two or more.

[0062] The maleimide resin contained in the resin composition can be a compound having an N-substituted maleimide group at each of both molecular terminals. As the compound having an N-substituted maleimide group at each of both molecular terminals, a compound represented by the following formula (A1) can be given.

[0063] [Chemical Formula 1]

[0064]

[0065] In the formula, X a11 is a divalent organic group. X a11 The structure of the divalent organic group represented by X a11The bivalent organic group shown can include a structure in which the same structural unit is connected, and can further include an N-substituted maleimide group.

[0066] The maleimide resin can include a fused ring of an aromatic ring and an aliphatic ring. As a preferred example of the fused ring of the aromatic ring and the aliphatic ring, an indane ring can be given. The indane ring refers to a condensed bicyclic structure of an aromatic 6-membered ring and a saturated aliphatic 5-membered ring. The indane ring included in the maleimide resin is preferably included in the form of a bivalent group represented by the following general formula (Al-1).

[0067] [Chemical Formula 2]

[0068]

[0069] In the formula, R a1 is an alkyl group having a carbon number of 1 to 10, an alkoxy group having a carbon number of 1 to 10, an alkylthio group having a carbon number of 1 to 10, an aryl group having a carbon number of 6 to 10, an aryloxy group having a carbon number of 6 to 10, an arylthio group having a carbon number of 6 to 10, a cycloalkyl group having a carbon number of 3 to 10, a halogen atom, a hydroxyl group, or a mercapto group. n a1 is an integer of 0 to 3. R a2 ~R a4 Each independently is an alkyl group having a carbon number of 1 to 10. * indicates a bonding site (the same hereinafter).

[0070] As the alkyl group having a carbon number of 1 to 10 represented by R a1 , a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, and the like can be given. These alkyl groups can be either of a straight chain or a branched chain.

[0071] As the alkyl group included in the alkoxy group having a carbon number of 1 to 10 and the alkylthio group having a carbon number of 1 to 10 represented by R a1 , the same alkyl groups as the above alkyl group having a carbon number of 1 to 10 can be given.

[0072] As the aryl group having a carbon number of 6 to 10 represented by R a1 , a phenyl group, a naphthyl group, and the like can be given.

[0073] As the aryl group included in the aryloxy group having a carbon number of 6 to 10 and the arylthio group having a carbon number of 6 to 10 represented by R a1 , the same aryl groups as the above aryl group having a carbon number of 6 to 10 can be given.

[0074] As the cycloalkyl group having a carbon number of 3 to 10 represented by R a1 , a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, and the like can be given.

[0075] From the viewpoints of solubility in a solvent and reactivity, R a1An alkyl group having a carbon number of 1 to 4, a cycloalkyl group having a carbon number of 3 to 6, or an aryl group having a carbon number of 6 to 10 is preferred, and an alkyl group having a carbon number of 1 to 4 is more preferred.

[0076] R a2 R a4 An alkyl group having a carbon number of 1 to 10 represented by R a2 R a4 An alkyl group having a carbon number of 1 to 4 is preferred, and a methyl group or an ethyl group is more preferred, and a methyl group is further preferred.

[0077] n a1 is an integer of 0 to 3. In the case where n a1 is 2 or 3, two or three R a1 may be the same or different.

[0078] From the viewpoint of ease of production, the divalent group represented by General Formula (A1-1) is preferably a group in which n a1 is 0, R a2 R a4 are each a methyl group. Specifically, a divalent group represented by the following General Formula (A1-1a) is preferred, and a divalent group represented by the following General Formula (A1-1a’) or a divalent group represented by the following General Formula (A1-1a”) is more preferred.

[0079] [Chemical Formula 3]

[0080]

[0081] The maleimide resin containing an indane ring is preferably an aromatic maleimide resin, more preferably an aromatic bismaleimide resin, and further preferably a compound represented by the following General Formula (A1-2).

[0082] [Chemical Formula 4]

[0083]

[0084] In the formula, R a1 R a4 and n a1 are the same as in General Formula (A1-1). R a5 are each independently an alkyl group having a carbon number of 1 to 10, an alkoxy group having a carbon number of 1 to 10, an alkylthio group having a carbon number of 1 to 10, an aryl group having a carbon number of 6 to 10, an aryloxy group having a carbon number of 6 to 10, an arylthio group having a carbon number of 6 to 10, a cycloalkyl group having a carbon number of 3 to 10, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. n a2 are each independently an integer of 0 to 4. n a3 is a number of 0.95 to 10.0.

[0085] wherein a plurality of R a1 , a plurality of n a1 , a plurality of R a5 , or a plurality of n a2 may be the same or different, respectively.

[0086] In the case where n a3 is more than 1, a plurality of R a2 , a plurality of R a3 , or a plurality of R a4 may be the same or different, respectively.

[0087] As the alkyl group having 1 to 10 carbons represented by R a5 , there can be mentioned methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, decyl group, and the like. These alkyl groups can be either linear or branched.

[0088] As the alkyl group contained in the alkoxy group having 1 to 10 carbons and the alkylthio group having 1 to 10 carbons represented by R a5 , there can be mentioned the same alkyl groups as mentioned above for the alkyl group having 1 to 10 carbons.

[0089] As the aryl group having 6 to 10 carbons represented by R a5 , there can be mentioned phenyl group, naphthyl group, and the like.

[0090] As the aryl group contained in the aryloxy group having 6 to 10 carbons and the arylthio group having 6 to 10 carbons represented by R a5 , there can be mentioned the same aryl groups as mentioned above for the aryl group having 6 to 10 carbons.

[0091] As the cycloalkyl group having 3 to 10 carbons represented by R a5 , there can be mentioned cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, and the like.

[0092] From the viewpoints of solvent solubility and ease of production, R a5 is preferably an alkyl group having 1 to 4 carbons, a cycloalkyl group having 3 to 6 carbons, or an aryl group having 6 to 10 carbons, more preferably an alkyl group having 1 to 3 carbons, and further preferably a methyl group.

[0093] In the formula, n a2 is an integer of 0 to 4, and from the viewpoints of compatibility with other resins, dielectric properties, conductor adhesion, and ease of production, is preferably an integer of 1 to 3, more preferably 2 or 3, and further preferably 2.

[0094] Note that by making n a21 or more, so that the benzene ring has a twisted conformation with respect to the N-substituted maleimide group, and there is a tendency for further improvement in solvent solubility by inhibiting intermolecular stacking. From the viewpoint of inhibiting intermolecular stacking, n a2 1 or more, so that the benzene ring has a twisted conformation with respect to the N-substituted maleimide group, and there is a tendency for further improvement in solvent solubility by inhibiting intermolecular stacking. From the viewpoint of inhibiting intermolecular stacking, n a5 The substituting position is preferably the ortho position with respect to the N-substituted maleimide group.

[0095] From the viewpoints of dielectric properties, conductor adhesion, solvent solubility, handling properties, and heat resistance, n a3 in the formula is preferably a number from 0.98 to 8.0, more preferably a number from 1.0 to 7.0, and further preferably a number from 1.1 to 6.0. Note that n a3 represents the average number of structural units containing an indane ring.

[0096] From the viewpoints of dielectric properties, conductor adhesion, solvent solubility, and ease of production, the maleimide resin represented by General Formula (A1-2) is more preferably a maleimide resin represented by the following General Formula (A1-3), or a maleimide resin represented by the following General Formula (A1-4).

[0097] [Chemical Formula 5]

[0098]

[0099] in the formula, R a1 to R a5 , n a1 , and n a3 are the same as in General Formula (A1-2).

[0100] [Chemical Formula 6]

[0101]

[0102] in the formula, R a1 to R a4 , n a1 , and n a3 are the same as in General Formula (A1-2).

[0103] As the maleimide resin represented by General Formula (A1-3), a maleimide resin represented by the following General Formula (A1-3-1), a maleimide resin represented by the following General Formula (A1-3-2), a maleimide resin represented by the following General Formula (A1-3-3), and the like can be given.

[0104] [Chemical Formula 7]

[0105]

[0106] in the formula, n a3the same as in General Formula (A1-2).

[0107] The maleimide resin (A1) represented by General Formula (A1-4) is preferably a maleimide resin represented by the following General Formula (A1-4-1).

[0108] [Chemical 8]

[0109]

[0110] in the formula, n a3 the same as in General Formula (A1-2).

[0111] The maleimide resin containing an indane ring can be synthesized by a publicly known method. For example, the maleimide resin containing an indane ring can be synthesized by the method described in International Publication No. 2023 / 282313.

[0112] In the case where the resin composition contains a maleimide resin as the curable resin and contains a maleimide resin containing an indane ring as the maleimide resin, the content ratio of the maleimide resin containing an indane ring is preferably greater than or equal to 50% by mass, more preferably greater than or equal to 70% by mass, and further preferably greater than or equal to 80% by mass, of the entire maleimide resin. The content ratio of the maleimide resin containing an indane ring can also be 100% by mass of the entire maleimide resin.

[0113] The number average molecular weight of the maleimide resin containing an indane ring is not particularly limited. From the viewpoint of the compatibility with other resins, the conductor adhesion, and the heat resistance, the number average molecular weight of the maleimide resin is preferably 600 to 3,000, more preferably 800 to 2,000, and further preferably 1,000 to 1,500.

[0114] In the present disclosure, the number average molecular weight or the weight average molecular weight of a compound is measured by gel permeation chromatography (GPC) in terms of polystyrene. The measurement conditions of GPC are shown below.

[0115] Apparatus: High-speed GPC device HLC-8320GPC

[0116] Detector: Ultraviolet absorbance detector UV-8320 [manufactured by Tosoh Corporation]

[0117] Column: Guard column; TSK Guardcolumn SuperHZ-L+column; TSKgel SuperHZM-N+TSKgel SuperHZM-M+TSKgel SuperH-RC (all manufactured by Tosoh Corporation, trade name)

[0118] Column dimensions: 4.6×20mm (protective column), 4.6×150mm (column), 6.0×150mm (reference column)

[0119] Eluent: Tetrahydrofuran

[0120] Sample concentration: 10 mg / 5 mL

[0121] Injection volume: 25μL

[0122] Flow rate: 1.00 mL / min

[0123] Measurement temperature: 40℃

[0124] The standard curve uses standard polystyrene: TSKstandard POLYSTYRENE (Type: A-2500, A-5000, F-1, F-2, F-4, F-10, F-20, F-40) (manufactured by Tosoh Corporation, trade name) and is approximated by a cubic formula.

[0125] When the resin composition contains maleimide resin other than maleimide resin containing indanthian ring as a curing resin, there is no particular limitation on the type of maleimide resin.

[0126] As specific examples of the maleimide resin other than the maleimide resin containing an indane ring, N,N'-ethylenebismaleimide, N,N'-hexamethylenebismaleimide, N,N'-(1,3- phenylene)bismaleimide, N,N'-[1,3-(2-methylphenylene)]bismaleimide, N,N'-[1,3-(4- methylphenylene)]bismaleimide, N,N'-(1,4-phenylene)bismaleimide, bis(4- maleimidephenyl)methane, bis(3-methyl-4-maleimidephenyl)methane, 3,3'-dimethyl-5,5'- diethyl-4,4'-diphenylmethane bismaleimide, bis(4-maleimidephenyl)ether, bis(4- maleimidephenyl)sulfone, bis(4-maleimidephenyl)sulfide, bis(4-maleimidephenyl)ketone, bis(4-maleimidecyclohexyl)methane, 1,4-bis(4-maleimidephenyl)cyclohexane, 1,4- bis(maleimide-methyl)cyclohexane, 1,4-bis(maleimide-methyl)benzene, 1,3-bis(4- maleimidephenoxy)benzene, 1,3-bis(3-maleimidephenoxy)benzene, bis[4-(3-4-bis(4-maleimidophenoxy) biphenyl, bis[4-(3-maleimidophenoxy)phenyl] ketone, bis[4-(4-maleimidophenoxy)phenyl] ketone, bis(4-maleimidophenyl) disulfide, bis[4-(3-maleimidophenoxy)phenyl] sulfide, bis[4-(4-maleimidophenoxy)phenyl] sulfide, bis[4-(3-maleimidophenoxy)phenyl] sulfoxide, bis[4-(4-maleimidophenoxy)phenyl] sulfoxide, bis[4-(3-maleimidophenoxy)phenyl] sulfone, bis[4-(4-maleimidophenoxy)phenyl] sulfone, bis[4-(3-maleimidophenoxy)phenyl] ether, bis[4-(4-maleimidophenoxy)phenyl] ether, 1,4-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidophenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, polyphenylmethane maleimide, biphenyl aralkyl type maleimide, and the like.

[0127] The resin composition can contain an aminomaleimide resin having a structural unit from a maleimide resin and a structural unit from a diamine compound as the maleimide resin.

[0128] In the case where the resin composition contains a maleimide resin as the curable resin, the proportion of the maleimide resin in the entire curable resin is not particularly limited. The proportion of the maleimide resin in the entire curable resin may, for example, be greater than or equal to 40% by volume, greater than or equal to 45% by volume, or greater than or equal to 50% by volume. The proportion of the maleimide resin in the entire curable resin may, for example, be less than or equal to 75% by volume, less than or equal to 70% by volume, or less than or equal to 65% by volume.

[0129] The resin composition can contain a compound having a (meth)acryloyl group as the curable resin. From the viewpoint of the property balance of the resin film, the resin composition preferably contains a compound having an N-substituted maleimide group and a compound having a (meth)acryloyl group as the curable resin, respectively.

[0130] The resin composition can contain only one compound having a (meth)acryloyl group, or can contain two or more compounds.

[0131] As the compound having a (meth)acryloyl group, a (meth)acrylate, a (meth)acrylate having 3 or more functions, and the like can be given.

[0132] As the di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, tricyclodecane di(meth)acrylate, 1,12-dodecanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, ethoxylated bisphenol F di(meth)acrylate, dioxane glycol di(meth)acrylate, and the like can be given.

[0133] As the dioxane glycol di(meth)acrylate, for example, 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxan-2-yl]-2,2-dimethyl ethyl acrylate, and the like can be given.

[0134] As the (meth)acrylate having 3 or more functions, for example, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and the like can be given.

[0135] From the viewpoint of the balance of properties of the resin film, the resin composition preferably contains a di(meth)acrylate, more preferably a di(meth)acrylate containing an alkylene group, further preferably a di(meth)acrylate in which (meth)acryloyl groups are bonded to both terminals of the alkylene group.

[0136] As the di(meth)acrylate containing an alkylene group, a diacrylate represented by the following general formula (B-1) and a dimethacrylate represented by the following general formula (B-2) are preferable, and the dimethacrylate represented by the following general formula (B-2) is more preferable.

[0137] [Chemical Formula 9]

[0138]

[0139] In the formula, R b1 is an alkylene group having a carbon number of 1 to 20.

[0140] R in the above general formulae (B-1) and (B-2) b1 The number of carbons of the alkylene group represented by the formula: -CnH2n- (wherein n represents an integer of 1 to 20) is preferably 4 to 18, more preferably 6 to 15, and further preferably 8 to 12.

[0141] As the alkylene group having a carbon number of 1 to 20, methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tetradecylene, pentadecylene, and the like can be given. The alkylene group can be any one of linear, branched, or cyclic, and is preferably linear.

[0142] The resin composition can contain a compound having a vinyl group as the curable resin. From the viewpoint of the property balance of the resin film, the resin composition preferably contains a compound having an N-substituted maleimide group and a compound having a vinyl group as the curable resin, respectively.

[0143] The resin composition can contain only one kind of compound having a vinyl group, or can contain two or more kinds thereof.

[0144] As the compound having a vinyl group, a conjugated diene polymer can be given.

[0145] In the present disclosure, the "conjugated diene polymer" means a polymer of a conjugated diene compound.

[0146] As the conjugated diene compound, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 1,3-hexadiene, and the like can be given.

[0147] The conjugated diene polymer can be a homopolymer of one kind of conjugated diene compound, or can be a copolymer of two or more kinds of conjugated diene compounds.

[0148] The conjugated diene polymer can be a copolymer of one or more kinds of conjugated diene compounds and one or more kinds of monomers other than the conjugated diene compound.

[0149] In the case where the conjugated diene polymer is a copolymer, the polymerization mode is not particularly limited, and can be any one of random polymerization, block polymerization, or graft polymerization.

[0150] From the viewpoint of the compatibility with other resins contained in the resin composition and the dielectric properties, as the conjugated diene polymer, a conjugated diene polymer having a plurality of vinyl groups in the side chain is preferred, and a conjugated diene polymer having a plurality of 1,2-vinyl groups in the side chain is more preferred.

[0151] The number of vinyl groups in 1 molecule of the conjugated diene polymer is not particularly limited, and is preferably 3 or more, more preferably 5 or more, and further preferably 10 or more, from the viewpoint of compatibility with other resins and dielectric properties.

[0152] The upper limit of the number of vinyl groups in 1 molecule of the conjugated diene polymer is not particularly limited, and can be 100 or less, 80 or less, or 60 or less.

[0153] As the conjugated diene polymer, mention can be made of polybutadiene having 1,2-vinyl groups, butadiene-styrene copolymer having 1,2-vinyl groups, polyisoprene having 1,2-vinyl groups, and the like. Among them, from the viewpoint of dielectric properties and heat resistance, polybutadiene having 1,2-vinyl groups and butadiene-styrene copolymer having 1,2-vinyl groups are preferred, and polybutadiene having 1,2-vinyl groups is more preferred. As the polybutadiene having 1,2-vinyl groups, polybutadiene homopolymer having 1,2-vinyl groups is preferred.

[0154] In the case where the conjugated diene polymer is polybutadiene having 1,2-vinyl groups, the content of structural units having 1,2-vinyl groups [hereinafter, sometimes referred to as "vinyl group content"] with respect to the total structural units from butadiene constituting the polybutadiene is not particularly limited. From the viewpoint of compatibility with other resins, dielectric properties, and heat resistance of the resin composition, the vinyl group content is preferably 50 mol% or more, more preferably 70 mol% or more, and further preferably 85 mol% or more. In addition, the upper limit of the vinyl group content is not particularly limited, and can be 100 mol% or less, 95 mol% or less, or 90 mol% or less.

[0155] The number average molecular weight of the conjugated diene polymer is not particularly limited. From the viewpoint of compatibility with other resins, dielectric properties, and heat resistance, it is preferably 1,000 to 3,000, more preferably 1,100 to 2,000, and further preferably 1,150 to 1,500.

[0156] (Reactive Elastomer)

[0157] The resin composition contains a reactive elastomer.

[0158] In the present disclosure, an "elastomer" refers to a compound having a glass transition temperature of 25°C or less, and either a number average molecular weight or a weight average molecular weight of 10,000 or more, as determined by differential scanning calorimetry in accordance with JIS K 6240:2011.

[0159] The number average molecular weight or the weight average molecular weight of the reactive elastomer can be selected, for example, from the range of 10,000 to 500,000.

[0160] The reactive elastomer contained in the resin composition can be only one or two or more.

[0161] The type of the reactive elastomer is not particularly limited, and examples thereof include polystyrene-based elastomers, polyolefin-based elastomers, polyurethane-based elastomers, polyphenylene ether-based elastomers, polyester-based elastomers, polyamide-based elastomers, and polyacrylic acid-based elastomers.

[0162] From the viewpoint of the dielectric properties of the cured product, as the reactive elastomer, a polystyrene-based elastomer having a reactive group (hereinafter, also referred to as a reactive polystyrene-based elastomer) is preferred. As the reactive polystyrene-based elastomer, an elastomer having a structural unit derived from a styrene compound represented by the following general formula (D3-1) is exemplified.

[0163] [Chem. 10]

[0164]

[0165] In the formula, R d1 is a hydrogen atom or an alkyl group having 1 to 5 carbons, and R d2 is an alkyl group having 1 to 5 carbons. n d1 is an integer of 0 to 5.

[0166] As the alkyl group having 1 to 5 carbons represented by R d1 and R d2 in the formula, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, and the like are exemplified. The alkyl group having 1 to 5 carbons can be either linear or branched. Among them, an alkyl group having 1 to 3 carbons is preferred, an alkyl group having 1 or 2 carbons is more preferred, and a methyl group is further preferred.

[0167] n d1 in the formula is an integer of 0 to 5, is preferably an integer of 0 to 2, is more preferably 0 or 1, and is further preferably 0.

[0168] The reactive polystyrene-based elastomer can contain a structural unit other than the structural unit derived from a styrene compound.

[0169] As the structural unit other than the structural unit derived from a styrene compound which the reactive polystyrene-based elastomer can contain, a structural unit derived from butadiene, a structural unit derived from isoprene, a structural unit derived from maleic acid, a structural unit derived from maleic anhydride, and the like are exemplified.

[0170] The structural unit from butadiene and the structural unit from isoprene described above can be hydrogenated to an extent that does not impair the reactivity of the reactive polystyrene-based elastomer. In the case of being hydrogenated, the structural unit from butadiene becomes a structural unit in which an ethylene unit and a butylene unit are mixed, and the structural unit from isoprene becomes a structural unit in which an ethylene unit and a propylene unit are mixed.

[0171] As the reactive polystyrene-based elastomer, specifically, a styrene-butadiene-styrene block copolymer (SBS) or a hydrogenated product thereof, a styrene-isoprene-styrene block copolymer (SIS) or a hydrogenated product thereof, a styrene-maleic anhydride copolymer, and the like can be given.

[0172] The reactive polystyrene-based elastomer preferably contains a carbon-carbon double bond as a reactive group, and more preferably contains a structural unit represented by Formula A: -CH2-CH=CH-CH2-.

[0173] As the reactive polystyrene-based elastomer containing the structural unit represented by Formula A, SBBS in which the carbon-carbon double bonds at the 1,2-bonding sites in the butadiene block of SBS are partially hydrogenated can be given. Among them, SBBS is preferred. The partial hydrogenation rate in SBBS can be, for example, 60% to 85% with respect to the carbon-carbon double bonds of the entire SBS.

[0174] The number average molecular weight of the reactive elastomer is not particularly limited, and is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and further preferably 100,000 to 200,000.

[0175] The weight average molecular weight of the reactive elastomer is not particularly limited, and is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and further preferably 100,000 to 200,000.

[0176] (Inorganic Filler)

[0177] The resin composition contains an inorganic filler.

[0178] By the resin composition containing an inorganic filler, there is a tendency that the thermal expansion rate of the cured product is reduced, and the heat resistance and the flame retardancy are improved.

[0179] The inorganic filler contained in the resin composition can be only one kind, or two or more kinds.

[0180] As the inorganic filler, there can be mentioned silica, alumina, titania, beryllia, barium titanate, potassium titanate, strontium titanate, calcium titanate, aluminum carbonate, magnesium hydroxide, aluminum hydroxide, aluminum silicate, calcium carbonate, calcium silicate, magnesium silicate, silicon nitride, boron nitride, aluminum borate, silicon carbide, and the like. Among them, from the viewpoints of low thermal expansion, heat resistance, and flame retardancy, silica and alumina are preferred.

[0181] The average particle diameter of the inorganic filler is not particularly limited, and from the viewpoints of dispersibility in the resin composition and suitability to fine wiring, it is preferably from 0.01 μm to 20 μm, more preferably from 0.1 μm to 10 μm, and further preferably from 0.5 μm to 5 μm.

[0182] In the present disclosure, the average particle diameter of the inorganic filler refers to the particle diameter at which the cumulative volume reaches 50% in the volume-based particle size distribution curve (volume average particle diameter, D50). The volume-based particle size distribution curve is obtained, for example, by a laser diffraction scattering method.

[0183] The shape of the inorganic filler is not particularly limited, and a spherical shape is preferred.

[0184] In order to improve dispersibility and improve adhesion to the organic component, the inorganic filler can be surface-treated with a coupling agent. As the coupling agent, there can be mentioned a silane coupling agent, a titanate coupling agent, and the like. Among them, a silane coupling agent is preferred. As the silane coupling agent, there can be mentioned an amino silane coupling agent, a vinyl silane coupling agent, an epoxy silane coupling agent, and the like.

[0185] (Curing Accelerator)

[0186] The resin composition can contain a curing accelerator. By the resin composition containing a curing accelerator, there is a tendency that the curability of the resin composition is improved, and the dielectric properties and heat resistance of the cured product are improved.

[0187] The kind of the curing accelerator is not particularly limited, and can be selected depending on the kind of the curable resin contained in the resin composition, and the like.

[0188] As the curing accelerator, acidic catalysts such as p-toluenesulfonic acid; amine compounds such as triethylamine, pyridine, tributylamine, and dicyandiamide; imidazole compounds such as methyl imidazole, phenylimidazole, and 1-cyanoethyl-2-phenylimidazole; isocyanate-enclosed imidazole compounds such as an addition product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole; tertiary amine compounds; quaternary ammonium compounds; phosphorus compounds such as triphenylphosphine; organic peroxides such as dicumyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, and tert-butylperoxy isopropyl monocarbonate; inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate; azo compounds such as 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis(4-methoxy-2'-dimethylvaleronitrile); and carboxylate salts of manganese, cobalt, and zinc can be given.

[0189] In the case where the resin composition contains a radically polymerizable curable resin, a radical polymerization initiator is preferably contained as the curing accelerator. As the radical polymerization initiator, the above-mentioned organic peroxide, inorganic peroxide, azo compound, and the like can be given. From the viewpoint of improving the curability, an organic peroxide is preferable.

[0190] The curing accelerator contained in the resin composition can be only one or two or more.

[0191] In the case where the resin composition contains a curing accelerator, the content thereof is not particularly limited, and is preferably 0.1 to 15 parts by mass, more preferably 1 to 10 parts by mass, and further preferably 4 to 8 parts by mass, relative to the total amount of the resin components (100 parts by mass).

[0192] If the content of the curing accelerator is greater than or equal to 0.1 parts by mass, there is a tendency that sufficient curing acceleration effect is obtained. If the content of the curing accelerator is less than or equal to 15 parts by mass, there is a tendency that the storage stability of the resin composition becomes more excellent.

[0193] In the case where the resin composition contains a radical polymerization initiator as the curing accelerator, the content thereof is not particularly limited, and is preferably 0.05 to 7 parts by mass, more preferably 0.5 to 5 parts by mass, and further preferably 2 to 4 parts by mass, relative to the total amount of the resin components (100 parts by mass).

[0194] If the content of the radical polymerization initiator is greater than or equal to the above lower limit value, there is a tendency that sufficient curing acceleration effect is easily obtained. In addition, if the content of the radical polymerization initiator is less than or equal to the above upper limit value, there is a tendency that the storage stability becomes more excellent.

[0195] (scaled particles)

[0196] The resin composition can contain scaled particles.

[0197] As shown in the examples described later, the coefficient of thermal expansion (CTE) of a cured product of a resin sheet formed from a resin composition containing scaled particles is reduced. Reducing the CTE of the resin sheet is advantageous in terms of reducing the difference in the coefficient of thermal expansion between a substrate to which the resin sheet is attached and suppressing warping of the substrate or the like.

[0198] The scaled particles contained in the resin composition can be only one kind, or two or more kinds.

[0199] The reason why the CTE of the cured product of the resin sheet containing scaled particles is reduced is not necessarily clear, but it can be considered that, for example, the scaled particles stacked along the thickness direction of the resin sheet hinder the shrinkage in the thickness direction of the resin sheet, as a result of which the expansion in the planar direction of the resin sheet is suppressed.

[0200] As the scaled particles contained in the resin sheet, particles having a scaled shape such as talc, mica, graphite, boron nitride, or the like can be used without particular limitation. The scaled particles can also be particles obtained by processing particles that are not in a scaled shape into a scaled shape.

[0201] The scaled particles can be surface-treated with a surface treatment agent. As the surface treatment agent, zinc molybdate or the like can be mentioned.

[0202] The average particle diameter of the scaled particles is not particularly limited, and is preferably from 0.01 μm to 20 μm, more preferably from 0.1 μm to 10 μm, and further preferably from 0.5 μm to 5 μm.

[0203] In the present disclosure, the average particle diameter of the scaled particles refers to the particle diameter at which the cumulative volume reaches 50% in a volume-based particle size distribution curve (volume average particle diameter, D50). The volume-based particle size distribution curve is obtained, for example, by a laser diffraction scattering method.

[0204] The average aspect ratio of the scaled particles is not particularly limited, and is preferably greater than or equal to 5, greater than or equal to 10, or greater than or equal to 50. The average aspect ratio of the scaled particles can be less than or equal to 200, less than or equal to 150, or less than or equal to 100. The average aspect ratio of the scaled particles is a value obtained by dividing the average value of the maximum diameters of 100 particles arbitrarily selected from an electron microscope image by the average value of the thicknesses.

[0205] In the case where the resin composition contains the flaky particles, the content thereof is not particularly limited, and is preferably 0.1 to 10 parts by mass, more preferably 1 to 7 parts by mass, and further preferably 2 to 5 parts by mass, relative to the total amount (100 parts by mass) of the resin component.

[0206] If the content of the curing accelerator is greater than or equal to 0.1 parts by mass, there is a tendency that the lowering effect of the CTE of the resin sheet is sufficiently obtained. If the content of the curing accelerator is less than or equal to 10 parts by mass, there is a tendency that the balance with other characteristics of the resin sheet becomes good.

[0207] (Other components)

[0208] The resin composition can contain a component other than the above-described components (other components) as necessary. As the other components, a flame retardant, an antioxidant, a heat stabilizer, an antistatic agent, an ultraviolet absorber, a colorant, a lubricant, and the like can be given.

[0209] The other components contained in the resin composition can be only one or two or more.

[0210] The content ratio of each component contained in the resin composition is not particularly limited, and can be selected depending on the use of the resin film or the like.

[0211] (Content ratio of essential components)

[0212] The content ratio of the essential components (the curable resin, the reactive elastomer, and the inorganic filler) contained in the resin composition is not particularly limited, and can be selected depending on the use of the resin film, the desired characteristics, or the like.

[0213] From the viewpoint of imparting sufficient curability to the resin film, the content ratio of the curable resin contained in the resin composition is preferably greater than or equal to 10% by volume, more preferably greater than or equal to 15% by volume, and further preferably greater than or equal to 18% by volume.

[0214] From the viewpoint of the balance with other components, the content ratio of the curable resin contained in the resin composition is preferably less than or equal to 50% by volume, more preferably less than or equal to 40% by volume, and further preferably less than or equal to 30% by volume.

[0215] From the viewpoint of improving the handleability of the resin film, the content ratio of the reactive elastomer contained in the resin composition is preferably greater than or equal to 5% by volume, more preferably greater than or equal to 10% by volume, and further preferably greater than or equal to 15% by volume.

[0216] The content of the reactive elastomer contained in the resin composition is preferably 30% by volume or less, more preferably 25% by volume or less, and further preferably 20% by volume or less, from the viewpoint of balance with other components.

[0217] The content of the inorganic filler contained in the resin composition is preferably 40% by volume or more, more preferably 45% by volume or more, and further preferably 50% by volume or more, from the viewpoint of reducing the thermal expansion rate of the resin film, improving heat resistance, improving flame retardancy, and the like.

[0218] The content of the inorganic filler contained in the resin composition is preferably 80% by volume or less, more preferably 75% by volume or less, and further preferably 70% by volume or less, from the viewpoint of balance with other components.

[0219] The proportion of the reactive elastomer in the resin component contained in the resin composition is preferably 30% by volume to 50% by volume, from the viewpoint of balance between suitability for polishing treatment and operability of the resin sheet.

[0220] The content of each component described above is a content based on the solid component contained in the resin composition.

[0221] In the present disclosure, the resin component refers to a component corresponding to an organic substance among the solid component contained in the resin composition.

[0222] (Variety of properties of the resin film)

[0223] The thickness of the resin film is not particularly limited and can be selected as appropriate in accordance with the purpose of the resin film, and the like. The thickness of the resin film may, for example, be 10 μm or more, 50 μm or more, 80 μm or more, or 100 μm or more.

[0224] The thickness of the resin film may, for example, be 1,000 μm or less, 700 μm or less, or 500 μm or less.

[0225] From the viewpoint of operability of the resin film, the resin film is preferably in a state of being disposed on a support.

[0226] The material of the support is not particularly limited and examples include resin, metal, paper, and the like. If necessary, the surface of the support that contacts the resin film can be subjected to a release treatment.

[0227] The thickness of the support is not particularly limited and, from the viewpoints of operability and economy, is preferably 10 μm to 150 μm, more preferably 20 μm to 100 μm, and further preferably 25 μm to 50 μm.

[0228] The resin film in a state disposed on the support can be produced, for example, by applying a resin varnish obtained by adding an organic solvent to a resin composition to the support and drying to remove the organic solvent.

[0229] The content of the organic solvent in the dried resin film is preferably 2% by mass or less, more preferably 1% by mass or less, and further preferably 0.5% by mass or less, and can be 0% by mass, relative to the total amount of the resin film (100% by mass).

[0230] If the content of the organic solvent in the resin film is in the above range, the amount of volatilization of the organic solvent during heat curing can be sufficiently suppressed.

[0231] The resin film can be in a state in which at least a part of the curable component contained in the resin film has reacted.

[0232] The resin film can be in a state in which a protective film is disposed on the surface. For example, the resin film can be in a state in which a support is disposed on one face and a protective film is disposed on the other face.

[0233] The material of the protective film is not particularly limited, and examples include resins, metals, paper, and the like. If desired, the face of the protective film that contacts the resin film can be subjected to a release treatment.

[0234] The thickness of the protective film is not particularly limited, and is preferably 10 μm to 150 μm, more preferably 20 μm to 100 μm, and further preferably 25 μm to 50 μm, from the viewpoints of workability and economy.

[0235] The use of the resin film of the present disclosure is not particularly limited. Examples of preferred uses include the formation of an insulating layer of a printed wiring board, the sealing of a semiconductor element contained in a semiconductor package, and the like. The resin film of the present disclosure is excellent in suitability for polishing treatment, and can therefore be suitably used for uses involving polishing treatment.

[0236] An example of polishing treatment performed on the resin film of the present disclosure is described with reference to the drawings.

[0237] First, as shown in (A), a substrate 20 on which a protrusion 10 is disposed is prepared. Next, as shown in (B), a resin film 30 is disposed on the substrate 20 so as to bury the protrusion 10. Next, as shown in (C), the resin film 30 is cured to obtain a cured product 40 of the resin film. Next, as shown in (D), the surface of the cured product 40 of the resin film is polished to expose the top of the protrusion 10. Figure 1 Figure 1 (B), a resin film 30 is disposed on the substrate 20 so as to bury the protrusion 10. Next, as shown in (C), the resin film 30 is cured to obtain a cured product 40 of the resin film. Next, as shown in (D), the surface of the cured product 40 of the resin film is polished to expose the top of the protrusion 10. Figure 1 Figure 1 (B), a resin film 30 is disposed on the substrate 20 so as to bury the protrusion 10. Next, as shown in (C), the resin film 30 is cured to obtain a cured product 40 of the resin film. Next, as shown in (D), the surface of the cured product 40 of the resin film is polished to expose the top of the protrusion 10.

[0238] Examples of the protrusion include Figure 1 ​​Examples of the protrusions 10 shown include metal pillars, metal posts, solder balls, wiring patterns, semiconductor chips, and the like. The protrusions 10 can also be portions that are raised between recesses such as grooves in the substrate.

[0239] The interval between adjacent protrusions 10 can be selected, for example, from between 10 μm and 200 μm. The height of the protrusions 10 can be selected, for example, from between 10 μm and 200 μm.

[0240] <Printed wiring board>

[0241] The printed wiring board of the present disclosure contains a cured product of the resin film described above. The cured product of the resin film can be, for example, an insulating layer disposed on a substrate contained in the printed wiring board. The printed wiring board can also be a multilayer printed wiring board.

[0242] Hereinafter, an example of a method of manufacturing a printed wiring board using the resin film of the present disclosure will be described.

[0243] First, the resin film is disposed on a substrate. The disposition of the resin film can be performed while the resin film is being subjected to pressure and heat. The resin film can be disposed on only one surface of the substrate, or on both surfaces.

[0244] As the substrate of the printed wiring board, a substrate (circuit substrate) in which a conductor layer as a circuit is formed in a pattern on the surface can be used. The substrate can be selected without particular limitation from among known substrates such as a glass epoxy substrate, a metal substrate, a polyester substrate, a polyimide substrate, a BT resin substrate, a thermosetting polyphenylene ether substrate, and the like.

[0245] Next, the resin film disposed on the substrate is cured to form an insulating layer. The conditions for curing are set in consideration of the components contained in the resin film and the like.

[0246] The insulating layer formed by curing the resin film can be subjected to, as necessary, hole processing, roughening treatment, polishing treatment, and the like.

[0247] A conductor layer can also be further disposed on the insulating layer formed by curing the resin film. The disposition of the conductor layer can be performed by a known method such as plating.

[0248] <Semiconductor package>

[0249] The semiconductor package of the present disclosure contains a cured product of the resin film described above. The cured product of the resin film can be, for example, a sealing portion disposed around an electronic component disposed on a substrate.

[0250] Next, the resin varnish layer is overlapped with the resin varnish layer in which the PET film is arranged on the other face in a state of facing each other. In this state, the resin varnish layers are adhered using a vacuum laminator at a temperature of 100°C for 5 seconds, whereby a resin film in which the PET film is arranged on both faces is obtained.

[0251] Example

[0252] Hereinafter, the present embodiment will be specifically described by citing examples. However, the present embodiment is not limited to the following examples.

[0253] (Production of resin film)

[0254] The components shown in Table 1 were mixed together with a solvent (toluene) to prepare a resin varnish having a solid component concentration of about 50 mass%. The unit of the compounding amount of the components described in Table 1 is "vol%" unless otherwise specified.

[0255] Next, the resin varnish was applied to one face of the PET film to form a resin varnish layer. Then, the resin varnish layer was heated and dried at 105°C for 5 minutes, whereby the solvent contained in the resin varnish layer was volatilized, and a resin composition layer in a state in which the PET film was arranged on one face was obtained.

[0256] Next, the resin composition layer in a state in which the PET film was arranged on one face was overlapped with the resin composition layer in a state in which the PET film was arranged on the other face in a manner of facing each other. In this state, the resin composition layers were adhered using a vacuum laminator at a temperature of 100°C for 5 seconds, whereby a resin film in a state in which the PET film was arranged on both faces was obtained.

[0257] (Curing treatment of resin film)

[0258] The PET film of the resin film obtained above was peeled off and removed. Next, a low-profile copper foil (manufactured by Mitsui Mining Co., Ltd., trade name "3EC-VLP-12") having a thickness of 12 μm was arranged on both faces of the resin film in a manner such that the S face became the resin film side, and in this state, the low-profile copper foil and the resin film were adhered using a vacuum laminator to obtain a laminate, and the adhering conditions were set to a temperature of 100°C, a vacuum time of 30 seconds, a pressure time of 20 seconds, and a pressure of 0.1 MPa, and the laminate was subjected to a curing treatment in which heating was performed at a temperature of 180°C for 1 hour, whereby a cured product of the resin film (thickness: 120 μm) was obtained.

[0259] (Measurement of storage modulus)

[0260] A cured product of the resin film obtained by the curing treatment was made into a test piece having a width of 0.4 mm, a length of 20 mm, and a thickness of 0.12 mm.

[0261] The test piece was subjected to measurement of the storage modulus by dynamic viscoelasticity measurement. The measurement was performed using Rheogel E4000 manufactured by UBM Co., Ltd., under conditions of a tensile mode, a frequency of 10 Hz, a sine wave, a load of 25 g, and a strain of 5 μm. The results of the measurement of the storage modulus at 25°C are shown in Table 1.

[0262] (Evaluation of abrasiveness)

[0263] A cured product of the resin film obtained by the curing treatment was laminated on a 12-inch silicon wafer, and the following grinding test was performed.

[0264] Apparatus: DAG-810 manufactured by DISCO Corporation

[0265] Grinding stone: GFCP-SD4000-VBD05-150 (#320, #4000)

[0266] Grinding conditions: feed method, processing speed 0.2 μm / s, rotation speed 2000 rpm

[0267] Grinding process: the thickness of the cured product was coarsely ground by 50 μm using the grinding stone of #320, and then the thickness of the cured product was ground by 20 μm using the grinding stone of #4000.

[0268] The appearance of the cured product after grinding was visually observed, and the evaluation was performed in accordance with the following criteria. The results are shown in Table 1.

[0269] The surface after grinding was glossy … ○

[0270] The surface after grinding was not glossy … x

[0271] As an index of the magnitude of the grinding load, the maximum value of the current value in the grinding test was measured. The results are shown in Table 1.

[0272] (Measurement of coefficient of thermal expansion)

[0273] A cured product of the resin film obtained by the curing treatment was made into a test piece having a width of 0.4 mm, a length of 20 mm, and a thickness of 0.12 mm.

[0274] The test piece was subjected to measurement of the coefficient of thermal expansion (CTE, ppm / K) by thermal mechanical analysis (TMA). The measurement was performed using SS6610 manufactured by Seiko Instruments Inc., under conditions of a tensile mode, a temperature range of 30°C to 300°C, a temperature increase rate of 5°C / min, and a load of 4 g. The results are shown in Table 1.

[0275] [Table 1]

[0276]

[0277] Details of the components described in Table 1 are as described below.

[0278] Curing resin 1: aromatic bismaleimide resin containing an indane ring represented by general formula (A1-4-1), number average molecular weight: 1,300, solid at 25°C

[0279] Curing resin 2: polybutadiene homopolymer having 1,2-vinyl, vinyl content: 85% or more, number average molecular weight: 1,200, liquid at 25°C

[0280] Curing resin 3: nonanediol dimethacrylate, liquid at 25°C, molecular weight: 296.4

[0281] Elastomer 1 (reactive): SBBS, weight average molecular weight: 100,000

[0282] Elastomer 2 (non-reactive): SEBS, weight average molecular weight: 200,000

[0283] Elastomer 3 (non-reactive): SEBS manufactured by a different manufacturer from elastomer 2

[0284] Elastomer 4 (non-reactive): SEBS manufactured by a different manufacturer from elastomer 2 and elastomer 3

[0285] Inorganic filler 1: silica particles having a volume average particle diameter of 2.4 μm

[0286] Inorganic filler 2: silica particles having a volume average particle diameter of 1.0 μm

[0287] Flaky particles: mixture of 75 mass% to 90 mass% talc and 10 mass% to 25 mass% zinc molybdate, talc having a volume average particle diameter of 3.3 μm, zinc molybdate having a volume average particle diameter of 1.0 μm

[0288] Coupling agent: 3-methacryloyloxypropyltrimethoxysilane

[0289] Curing accelerator 1: 1,3-bis(tert-butylperoxyisopropyl)benzene

[0290] Curing accelerator 2: imidazole-based curing accelerator

[0291] The amount of the flaky particles shown in Table 1 is the amount relative to the total (100 parts by mass) of the resin components.

[0292] As shown in Table 1, the resin film of the examples containing the reactive elastomer had a good surface state after polishing, and the maximum value of the current value and the maximum load in the polishing test were small, as compared with the resin film of the comparative example not containing the reactive elastomer. From the above results, it was found that the resin film containing the reactive elastomer was excellent in suitability to polishing treatment.

[0293] Further, as can be seen from the comparison of Examples 2, 4, and 5, the resin film containing the scale-like particles had a lower coefficient of thermal expansion in the cured state, as compared with the resin film not containing the scale-like particles.

[0294] The disclosure of Japanese Patent Application No. 2024-013689 is incorporated by reference herein in its entirety.

[0295] All of the literature, patent applications and technical standards cited in the present specification are hereby incorporated by reference to the same extent as if the literature, patent applications, and technical standards were specifically and individually indicated to be incorporated by reference.

Claims

1. A resin film formed from a resin composition comprising a curable resin, an elastomer, and an inorganic filler material, the elastomer comprising a reactive group.

2. The resin film according to claim 1, having a storage modulus at 25°C of less than or equal to 5.5 GPa as measured in a cured state.

3. The resin film according to claim 1, the curable resin comprising a radically polymerizable curable resin.

4. The resin film according to claim 1, the inorganic filler material being contained at a rate of 50 to 70 vol%.

5. The resin film according to any one of claims 1 to 4, for use as a sealing material for a semiconductor package.

6. The resin film according to any one of claims 1 to 4, for use in forming an insulating layer of a printed wiring board.

7. A printed wiring board comprising a cured product of the resin film according to any one of claims 1 to 4.

8. A semiconductor package comprising a cured product of the resin film according to any one of claims 1 to 4.

Images