Resin film, printed wiring board, and semiconductor package

Abstract

A resin film comprising a resin composition containing a curable resin, an elastomer, and an inorganic filler, the storage elastic modulus at 25°C measured in a cured state being greater than or equal to 4 GPa.

Description

Technical Field

[0001] This disclosure relates to resin films, printed wiring boards, and semiconductor packaging. Background Technology

[0002] In electronic components such as printed wiring boards and semiconductor packages, insulating materials are used for the purpose of protecting components and wiring, and providing electrical insulation. As such insulating materials, resin compositions in various forms, such as liquid, tablet, and sheet, have been developed.

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

[0004] Patent Document 1: International Publication No. 2023 / 282313 Summary of the Invention

[0005] The problem that the invention aims to solve

[0006] Resin films containing curable resins are sometimes used in processes to insulate terminals that electrically connect two opposing components (e.g., a substrate and a semiconductor chip disposed on the substrate).

[0007] Specifically, a resin film is disposed on a substrate with terminals on its surface, and the portion of the resin film opposite to the substrate is deformed to fill the gaps between the terminals. Next, the resin film, which fills the gaps between the terminals and covers the tops of the terminals, is cured. Then, the resin film is ground (polished) to expose the tops of the terminals covered by the resin film.

[0008] The inventors' research results show that there is room for improvement in the adaptability of conventional resin films to grinding processes.

[0009] In view of the above, one objective of this disclosure is to provide a resin film with excellent adaptability to grinding processes, a printed wiring board obtained using the resin film, and a semiconductor package obtained using the resin film.

[0010] Methods for solving problems

[0011] The specific means to solve the above problems include the following methods.

[0012] <1> A resin membrane comprising a resin composition containing a curable resin, an elastomer, and an inorganic filler, wherein the storage modulus of the resin membrane at 25°C, measured in the cured state, is greater than or equal to 4 GPa.

[0013] <2> according to <1> The resin membrane, wherein the storage modulus is less than or equal to 10 GPa.

[0014] <3> according to <1> or <2> The resin film, wherein the curable resin comprises a free radical polymerizable curable resin.

[0015] <4> according to <1> ~ <3> The resin film according to any one of the following methods, wherein the content of the inorganic filler material is 50% to 70% by volume.

[0016] <5> according to <1> ~ <4> The resin film described in any one of the above examples is used as a sealing material for semiconductor packaging.

[0017] <6> according to <1> ~ <4> The resin film described in any one of the above statements is used to form an insulating layer on a printed wiring board.

[0018] <7> A printed wiring board comprising <1> ~ <4> The cured product of the resin film as described in any one of the above.

[0019] <8> A semiconductor package comprising <1> ~ <4> The cured product of the resin film as described in any one of the above.

[0020] Invention Effects

[0021] According to one embodiment of the present disclosure, a resin film with excellent adaptability to grinding processes, a printed wiring board obtained using the resin film, and a semiconductor package obtained using the resin film are provided. Attached Figure Description

[0022] Figure 1 This is a diagram that schematically illustrates an example of a grinding process using the resin film of this disclosure. Detailed Implementation

[0023] In this disclosure, the term "process" includes not only processes that are independent of other processes, but also processes that cannot be clearly distinguished from other processes, as long as the purpose of the process can be achieved.

[0024] In this disclosure, within the numerical range represented by "~", the values ​​recorded before and after "~" are respectively the minimum and maximum values.

[0025] In the numerical ranges described in this disclosure, the upper or lower limit of one numerical range can be replaced by the upper or lower limit of other numerical ranges described in other stages. Furthermore, the upper or lower limit of the numerical ranges described in this disclosure can also be replaced by the values ​​shown in the embodiments.

[0026] In this disclosure, each component may comprise multiple corresponding substances. In the presence of multiple substances equivalent to each component in the composition, unless otherwise specified, the content or percentage of each component refers to the total content or percentage of the multiple substances present in the composition.

[0027] In this disclosure, "resin composition" refers to a mixture containing at least two or more components of resin. When the resin composition contains a curing component, the state in which at least a portion of the curing component has reacted is also included in the resin composition.

[0028] In this disclosure, "solid components" refers to components other than volatile components such as solvents.

[0029] In this disclosure, "(meth)acrylate" means "acrylate" or "methacrylate", "(meth)acrylic acid" means "acrylic acid" or "methacrylic acid", and "(meth)acryloyl" means "acryloyl" or "methacryloyl".

[0030] Regarding the "molecular weight" of the compounds in this disclosure, if the compound is not a polymer but its structural formula can be determined, it refers to the molecular weight that can be calculated from the structural formula; if the compound is a polymer, it is the exponential average molecular weight or the weight average molecular weight.

[0031] The mechanisms of action described in this specification are speculative and do not limit the mechanisms by which the resin composition of this embodiment exerts its effects.

[0032] This embodiment also includes any combination of the items described in this specification.

[0033] <Resin Film>

[0034] The resin membrane disclosed herein comprises a resin composition containing a curable resin, an elastomer, and an inorganic filler, and has a storage modulus at 25°C greater than or equal to 4 GPa when measured in the cured state.

[0035] As shown in the embodiments described later, the resin film of this disclosure exhibits excellent adaptability to grinding processes performed after curing.

[0036] In particular, the resin film of this disclosure exhibits excellent adaptability to grinding processes even when it contains elastomers.

[0037] As a means to improve the adaptability of resin films to grinding processes, it is also possible to exclude elastomers from the resin films. However, if the elastomer is removed in order to improve adaptability to grinding processes, other problems may occur, such as increased warpage of the substrate to which the resin film is attached.

[0038] The resin film disclosed herein achieves excellent adaptability to grinding processes even when containing elastomers, by having a storage modulus greater than or equal to 4 GPa as measured in the cured state.

[0039] From the viewpoint of adaptability to grinding processes, the above-mentioned energy storage modulus is preferably greater than or equal to 4.5 GPa, more preferably greater than or equal to 5 GPa.

[0040] From the viewpoint of suppressing warping of the substrate to which the resin film is attached, the above-mentioned energy storage modulus is preferably less than or equal to 10 GPa, more preferably less than or equal to 9 GPa, and even more preferably less than or equal to 8 GPa.

[0041] In this disclosure, the above-mentioned energy storage modulus is determined by dynamic viscoelasticity measurement (DMA) under the conditions described in the embodiments.

[0042] The resin film disclosed herein comprises a resin composition containing a curable resin, an elastomer, and an inorganic filler.

[0043] The following describes the components that may be contained in the resin composition constituting the resin film of this disclosure.

[0044] (Curing resin)

[0045] The resin composition contains a curable resin.

[0046] In this disclosure, a curable resin refers to a resin that exhibits the property of undergoing a chemical reaction and curing upon treatment such as heating or exposure to active radiation.

[0047] Examples of curable resins that may be included in a resin composition include compounds having functional groups such as N-substituted maleimide, vinyl, (meth)acryloyl, epoxy, hydroxyl, carboxyl, and amino as reactive groups.

[0048] From the perspective of adaptability to the manufacturing process of electronic components and heat resistance, the curable resin is preferably a thermosetting resin that exhibits the property of curing by heating.

[0049] One type of curing resin can be used alone, or two or more types can be used in combination.

[0050] From the viewpoint of the operability of the resin film, it is preferable that at least one of the curable resins contained in the resin composition is solid at 25°C, and more preferably that at least one of the curable resins contained in the resin composition is solid at 25°C and at least one is liquid at 25°C.

[0051] The curable resin contained in the resin composition can be free radical polymerizable.

[0052] Resin compositions containing curable resins with free radical polymerization properties, such as those containing epoxy resins, are less prone to changes in properties during storage. Therefore, they have advantages such as being able to be stored at room temperature.

[0053] Among free radical polymerizable curable resins, maleimide resins are preferred from the viewpoint of heat resistance and dielectric properties (low dielectric constant).

[0054] In this disclosure, maleimide resin refers to a compound having an N-substituted maleimide group as a reactive group.

[0055] From the viewpoint of curing reactivity, maleimide resins are preferably compounds having two N-substituted maleimide groups (hereinafter also referred to as bismaleimide resins) or compounds having three or more N-substituted maleimide groups (hereinafter also referred to as polymaleimide resins).

[0056] From the viewpoint of heat resistance, maleimide resins are preferably compounds having N-substituted maleimide groups directly bonded to the aromatic ring (hereinafter also referred to as aromatic maleimide resins), and more preferably compounds having two or more or three N-substituted maleimide groups directly bonded to the aromatic ring (hereinafter also referred to as aromatic bismaleimide resins or aromatic polymaleimide resins).

[0057] The maleimide resin contained in the resin composition may be only one type or two or more types.

[0058] The maleimide resin contained in the resin composition can be a compound having N-substituted maleimide groups at both ends of the molecule. Examples of compounds having N-substituted maleimide groups at both ends of the molecule include compounds represented by the following formula (A1).

[0059]

[0060] In the formula, X a11 It is a divalent organic group. X a11 There are no particular restrictions on the structure of the divalent organic group represented. X a11 The divalent organic group represented may contain a structure formed by the connection of the same structural units, or may further contain an N-substituted maleimide group.

[0061] Maleimide resins can contain fused rings of aromatic and aliphatic rings. A preferred example of a fused ring of aromatic and aliphatic rings is the indane ring. An indane ring refers to a fused bicyclic structure of an aromatic 6-membered ring and a saturated aliphatic 5-membered ring. The indane ring contained in the maleimide resin is preferably contained in the form of a divalent group represented by the following general formula (A1-1).

[0062]

[0063] In the formula, R a1 It can be an alkyl group with 1 to 10 carbon atoms, an alkoxy group with 1 to 10 carbon atoms, an alkylthio group with 1 to 10 carbon atoms, an aryl group with 6 to 10 carbon atoms, an aryloxy group with 6 to 10 carbon atoms, an arylthio group with 6 to 10 carbon atoms, a cycloalkyl group with 3 to 10 carbon atoms, a halogen atom, a hydroxyl group, or a mercapto group. a1 Integers between 0 and 3. R a2 ~R a4 Each is an alkyl group having 1 to 10 carbon atoms. Indicates the bonding site (the same applies below).

[0064] As R a1 Examples of alkyl groups with 1 to 10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl. These alkyl groups can be either straight-chain or branched.

[0065] As R a1 The alkyl groups contained in the alkoxy groups having 1 to 10 carbon atoms and the alkylthio groups having 1 to 10 carbon atoms can be alkyl groups that are the same as the alkyl groups having 1 to 10 carbon atoms mentioned above.

[0066] As R a1 Examples of aryl groups representing 6 to 10 carbon atoms include phenyl and naphthyl groups.

[0067] As R a1 The aryl groups contained in the aryloxy groups with 6 to 10 carbon atoms and the arylthio groups with 6 to 10 carbon atoms can be exemplified by aryl groups with the same number of carbon atoms as the aforementioned aryl groups with 6 to 10 carbon atoms.

[0068] As R a1 Examples of cycloalkyl groups with 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl.

[0069] From the perspective of solubility and reactivity in solvents, R a1 Preferably, it is an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and more preferably an alkyl group having 1 to 4 carbon atoms.

[0070] As R a2 ~R a4 Examples of alkyl groups with 1 to 10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl. These alkyl groups can be either straight-chain or branched. Wherein, R...a2 ~R a4 Preferably, it is an alkyl group having 1 to 4 carbon atoms, more preferably methyl or ethyl, and even more preferably methyl.

[0071] n a1 Integers between 0 and 3. When n a1 When it is 2 or 3, there are 2 or 3 Rs. a1 They can be the same or different.

[0072] From the viewpoint of ease of manufacture, the divalent group represented by the general formula (A1-1) is preferably n. a1 =0, R a2 ~R a4 The divalent group is methyl. Specifically, the divalent group represented by the following formula (A1-1a) is preferred, and the divalent group represented by the following formula (A1-1a') or the divalent group represented by the following formula (A1-1a”) is more preferred.

[0073]

[0074] The maleimide resin containing an indanium ring is preferably an aromatic maleimide resin, more preferably an aromatic bismaleimide resin, and even more preferably a compound represented by the following general formula (A1-2).

[0075]

[0076] In the formula, R a1 ~R a4 and n a1 Same as in general formula (A1-1). R a5 Each of the following is independently an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, an alkylthio group having 1 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an arylthio group having 6 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a halogen atom, a nitro group, a hydroxyl group, or a mercapto group. a2 Each is an independent integer between 0 and 4. a3 Numbers ranging from 0.95 to 10.0.

[0077] In the formula, multiple R a1 Multiple n a1 Multiple R a5 or multiple n a2 They can be the same or different.

[0078] When n a3 When it exceeds 1, multiple R a2 Multiple R a3 or multiple R a4 They can be the same or different.

[0079] As R a5 Examples of alkyl groups with 1 to 10 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl. These alkyl groups can be either straight-chain or branched.

[0080] As R a5 The alkyl groups contained in the alkoxy groups having 1 to 10 carbon atoms and the alkylthio groups having 1 to 10 carbon atoms can be alkyl groups that are the same as the alkyl groups having 1 to 10 carbon atoms mentioned above.

[0081] As R a5 Examples of aryl groups representing 6 to 10 carbon atoms include phenyl and naphthyl groups.

[0082] As R a5 The aryl groups contained in the aryloxy groups with 6 to 10 carbon atoms and the arylthio groups with 6 to 10 carbon atoms can be exemplified by aryl groups with the same number of carbon atoms as the aforementioned aryl groups with 6 to 10 carbon atoms.

[0083] As R a5 Examples of cycloalkyl groups with 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclodecyl.

[0084] From the perspective of solvent solubility and ease of manufacture, R a5 Preferably, it is an alkyl group with 1 to 4 carbon atoms, a cycloalkyl group with 3 to 6 carbon atoms, or an aryl group with 6 to 10 carbon atoms; more preferably, it is an alkyl group with 1 to 3 carbon atoms; and even more preferably, it is a methyl group.

[0085] n in the formula a2 The value is an integer from 0 to 4. From the viewpoint of compatibility with other resins, dielectric properties, conductor adhesion and ease of manufacture, it is preferably an integer from 1 to 3, more preferably 2 or 3, and even more preferably 2.

[0086] Additionally, by making n a2 A value greater than or equal to 1, resulting in a conformation with a benzene ring twisted by an N-substituted maleimide group, tends to further enhance solvent solubility by suppressing intermolecular stacking. From the perspective of suppressing intermolecular stacking, in n... a2 When R is greater than or equal to 1, a5 The substitution position is preferably ortho relative to the N-substituted maleimide group.

[0087] From the perspectives of dielectric properties, conductor adhesion, solvent solubility, processability, and heat resistance, n in the formula... a3 The number is preferably in the range of 0.98 to 8.0, more preferably in the range of 1.0 to 7.0, and even more preferably in the range of 1.1 to 6.0. It should be noted that na3 This represents the average number of structural units containing indrin rings.

[0088] From the viewpoints of dielectric properties, conductor adhesion, solvent solubility and ease of manufacture, the maleimide resin represented by general formula (A1-2) is more preferably the maleimide resin represented by general formula (A1-3) or the maleimide resin represented by general formula (A1-4).

[0089]

[0090] In the formula, R a1 ~R a5 n a1 and n a3 Same as in general formula (A1-2).

[0091]

[0092] In the formula, R a1 ~R a4 n a1 and n a3 Same as in general formula (A1-2).

[0093] Examples of maleimide resins represented by general formula (A1-3) include maleimide resins represented by general formula (A1-3-1), maleimide resins represented by general formula (A1-3-2), and maleimide resins represented by general formula (A1-3-3).

[0094]

[0095] In the formula, n a3 Same as in general formula (A1-2).

[0096] The maleimide resin (A1) represented by general formula (A1-4) is preferably the maleimide resin represented by the following general formula (A1-4-1).

[0097]

[0098] In the formula, n a3 Same as in general formula (A1-2).

[0099] Maleimide resins containing indanium rings can be synthesized by known methods. For example, maleimide resins containing indanium rings can be synthesized by the method described in International Publication No. 2023 / 282313.

[0100] When the resin composition contains maleimide resin as a curing resin and also contains maleimide resin containing an indane ring as a maleimide resin, the content of the maleimide resin containing the indane ring is preferably greater than or equal to 50% by mass of the total maleimide resin, more preferably greater than or equal to 70% by mass, and even more preferably greater than or equal to 80% by mass. The content of the maleimide resin containing the indane ring can also be 100% by mass of the total maleimide resin.

[0101] The number-average molecular weight of maleimide resins containing indanthian rings is not particularly limited. From the viewpoint of compatibility with other resins, conductor adhesion and heat resistance, the number-average molecular weight of maleimide resins is preferably 600 to 3,000, more preferably 800 to 2,000, and even more preferably 1,000 to 1,500.

[0102] In this disclosure, the number-average molecular weight or weight-average molecular weight of the compounds can be determined by gel permeation chromatography (GPC) to polystyrene. The determination conditions for GPC are as follows.

[0103] Equipment: High-speed GPC device HLC-8320 GPC

[0104] Detector: UV-8320 ultraviolet absorbance detector [manufactured by Tosoh Corporation]

[0105] Columns: Protective column; TSK Guardcolumn SuperHZ-L+ column; TSKgel SuperHZM-N + TSKgel SuperHZM-M + TSKgel SuperH-RC (all manufactured by Tosoh Corporation, trade names)

[0106] Column dimensions: 4.6×20mm (protective column), 4.6×150mm (column), 6.0×150mm (reference column)

[0107] Eluent: Tetrahydrofuran

[0108] Sample concentration: 10 mg / 5 mL

[0109] Injection volume: 25 μL

[0110] Flow rate: 1.00 mL / min

[0111] Measurement temperature: 40℃

[0112] The standard curve uses standard polystyrene: TSK standard POLYSTYRENE (models: 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.

[0113] There are no particular restrictions on the type of maleimide resin used as a curing resin, except for maleimide resins containing indanthian rings.

[0114] Specific examples of maleimide resins other than those containing an indane ring include N,N'-ethylidene bismaleimide, N,N'-hexamethylene bismaleimide, 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, and bis(3-methyl-4-maleimidephenyl)methane. (Iminephenyl)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(maleimidemethyl)cyclohexane, 1,4-bis(maleimidemethyl)benzene, 1,3-bis(4-maleimidephenoxy) Benzene, 1,3-bis(3-maleimidephenoxy)benzene, bis[4-(3-maleimidephenoxy)phenyl]methane, bis[4-(4-maleimidephenoxy)phenyl]methane, 1,1-bis[4-(3-maleimidephenoxy)phenyl]ethane, 1,1-bis[4-(4-maleimidephenoxy)phenyl]ethane, 1,2-bis[4-(3-maleimidephenoxy)phenyl]ethane, 1,2-bis[4-(4-maleimidephenoxy)phenyl]ethane, 2,2-bis[4-(3-maleimidephenoxy)phenyl]ethane [4,2-bis[4-(4-maleimidephenoxy)phenyl]propane, 2,2-bis[4-(3-maleimidephenoxy)phenyl]butane, 2,2-bis[4-(4-maleimidephenoxy)phenyl]butane, 2,2-bis[4-(4-maleimidephenoxy)phenyl]butane, 2,2-bis[4-(3-maleimidephenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 2,2-bis[4-(4-maleimidephenoxy)phenyl]-1,1,3,3,3-hexafluoropropane, 4,4-bis(3-maleimidephenoxy)biphenyl, 4,4-Bis(4-maleimidephenoxy)biphenyl, bis[4-(3-maleimidephenoxy)phenyl]one, bis[4-(4-maleimidephenoxy)phenyl]one, bis(4-maleimidephenyl)disulfide, bis[4-(3-maleimidephenoxy)phenyl]sulfide, bis[4-(4-maleimidephenoxy)phenyl]sulfide, bis[4-(3-maleimidephenoxy)phenyl]sulfide, bis[4-(3-maleimidephenoxy)phenyl] Sulfoxide, bis[4-(4-maleimidephenoxy)phenyl] sulfoxide, bis[4-(3-maleimidephenoxy)phenyl] sulfone, bis[4-(4-maleimidephenoxy)phenyl] sulfone, bis[4-(3-maleimidephenoxy)phenyl] ether, bis[4-(4-maleimidephenoxy)phenyl] ether, 1,4-bis[4-(4-maleimidephenoxy)-α,α-dimethylbenzyl]benzene, 1 3-Bis[4-(4-maleimidephenoxy)-α,α-dimethylbenzyl]benzene, 1,4-Bis[4-(3-maleimidephenoxy)-α,α-dimethylbenzyl]benzene, 1,3-Bis[4-(3-maleimidephenoxy)-α,α-dimethylbenzyl]benzene, 1,4-Bis[4-(4-maleimidephenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3- Bis[4-(4-maleimidephenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,4-bis[4-(3-maleimidephenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(3-maleimidephenoxy)-3,5-dimethyl-α,α-dimethylbenzyl]benzene, polyphenylmethane maleimide, biphenyl aralkyl maleimide, etc.

[0115] The resin composition may also comprise an aminomaleimide resin having structural units from maleimide resins and structural units from diamine compounds as a maleimide resin.

[0116] When the resin composition contains maleimide resin as a curing resin, the proportion of maleimide resin in the total curing resin may be, for example, 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. Alternatively, the proportion of maleimide resin in the total curing resin may be, for example, 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.

[0117] The resin composition may contain a compound having a (meth)acrylyl group as a curable resin. From the viewpoint of balancing the properties of the resin film, the resin composition preferably contains a compound having an N-substituted maleimide group and a compound having a (meth)acrylyl group as curable resins, respectively.

[0118] The resin composition may contain only one compound having a (meth)acryloyl group, or it may contain two or more compounds.

[0119] Examples of compounds having a (meth)acryloyl group include di(meth)acrylates, (meth)acrylates with three or more functions, and other (meth)acrylates.

[0120] Examples of di(meth)acrylates include 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, and dioxanediol di(meth)acrylate.

[0121] Examples of dioxanediol di(meth)acrylates include 2-[5-ethyl-5-[(acryloyloxy)methyl]-1,3-dioxane-2-yl]-2,2-dimethylethyl acrylate.

[0122] Examples of trifunctional or higher (meth)acrylates include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0123] From the viewpoint of balancing the properties of the resin film, the resin composition preferably contains di(meth)acrylate, more preferably di(meth)acrylate containing alkylene groups, and even more preferably di(meth)acrylate containing (meth)acryloyl groups bonded to both ends of the alkylene groups.

[0124] As a di(meth)acrylate containing an alkylene group, the diacrylate represented by the following general formula (B-1) and the dimethacrylate represented by the following general formula (B-2) are preferred, and the dimethacrylate represented by the following general formula (B-2) is more preferred.

[0125]

[0126] In the formula, R b1 It is an alkylene group having 1 to 20 carbon atoms.

[0127] In the above general formulas (B-1) and (B-2), Rb1 The alkylene group with 1 to 20 carbon atoms preferably has 4 to 18 carbon atoms, more preferably 6 to 15, and even more preferably 8 to 12.

[0128] Examples of alkylene groups having 1 to 20 carbon atoms include methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecylene, dodecylene, tetradecylene, and pentadecylene. The alkylene group can be linear, branched, or cyclic, preferably linear.

[0129] The resin composition may contain a vinyl compound as a curable resin. From the viewpoint of balancing the properties of the resin film, the resin composition preferably contains a compound having an N-substituted maleimide group and a vinyl compound as curable resins, respectively.

[0130] The resin composition may contain only one compound having a vinyl group, or it may contain two or more compounds.

[0131] Examples of compounds containing vinyl groups include conjugated diene polymers.

[0132] In this disclosure, "conjugated diene polymer" refers to a polymer of conjugated diene compounds.

[0133] Examples of conjugated diene compounds include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-phenyl-1,3-butadiene, and 1,3-hexadiene.

[0134] Conjugated diene polymers can be homopolymers of one type of conjugated diene compound or copolymers of two or more conjugated diene compounds.

[0135] Conjugated diene polymers can be copolymers of one or more conjugated diene compounds with one or more monomers other than conjugated diene compounds.

[0136] There are no particular restrictions on the polymerization method when the conjugated diene polymer is a copolymer; it can be any of random polymerization, block polymerization, or graft polymerization.

[0137] From the viewpoint of compatibility with other resins contained in the resin composition and dielectric properties, conjugated diene polymers with a plurality of vinyl groups on the side chain are preferred, and conjugated diene polymers with a plurality of 1,2-vinyl groups on the side chain are more preferred.

[0138] The number of vinyl groups in one molecule of the conjugated diene polymer is not particularly limited, but from the viewpoint of compatibility with other resins and dielectric properties, it is preferred to have more than or equal to 3, more preferably more than or equal to 5, and even more preferably more than or equal to 10.

[0139] There is no particular limit to the number of vinyl groups in a single molecule of a conjugated diene polymer; it can be less than or equal to 100, less than or equal to 80, or less than or equal to 60.

[0140] Examples of conjugated diene polymers include 1,2-vinyl polybutadiene, 1,2-vinyl butadiene-styrene copolymers, and 1,2-vinyl polyisoprene. From the viewpoint of dielectric properties and heat resistance, 1,2-vinyl polybutadiene and 1,2-vinyl butadiene-styrene copolymers are preferred, and 1,2-vinyl polybutadiene is more preferred. As for 1,2-vinyl polybutadiene, 1,2-vinyl polybutadiene homopolymers are preferred.

[0141] When the conjugated diene polymer is polybutadiene having 1,2-vinyl groups, the content of the 1,2-vinyl structural units [hereinafter sometimes referred to as "vinyl content"] relative to all the structural units from butadiene constituting the polybutadiene is not particularly limited. From the viewpoint of compatibility with other resins contained in the resin composition, dielectric properties, and heat resistance, the vinyl content is preferably greater than or equal to 50 mol%, more preferably greater than or equal to 70 mol%, and even more preferably greater than or equal to 85 mol%. Furthermore, there is no particular upper limit to the vinyl content; it can be less than or equal to 100 mol%, less than or equal to 95 mol%, or less than or equal to 90 mol%.

[0142] 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, a number average molecular weight of 1,000 to 3,000 is preferred, more preferably 1,100 to 2,000, and even more preferably 1,150 to 1,500.

[0143] (elastomer)

[0144] The resin composition contains an elastomer.

[0145] In this disclosure, "elastomer" means a compound having a glass transition temperature of less than or equal to 25°C and a number-average molecular weight or weight-average molecular weight of greater than or equal to 10,000, as determined by differential scanning calorimetry according to JIS K 6240:2011.

[0146] The number-average molecular weight or weight-average molecular weight of the elastomer can be selected from, for example, in the range of 10,000 to 500,000.

[0147] The elastomer contained in the resin composition may be only one type or two or more types.

[0148] The elastomer contained in the resin composition may have the properties of a curable resin (i.e., have reactive groups) or may not have the properties of a curable resin (i.e., do not have reactive groups).

[0149] Examples of elastomers 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.

[0150] From the viewpoint of the dielectric properties of the cured product, the resin composition preferably contains a polystyrene-based elastomer. Examples of polystyrene-based elastomers include those having structural units derived from styrene compounds represented by the following general formula (D3-1).

[0151]

[0152] In the formula, R d1 R is an alkyl group having 1 to 5 carbon atoms or hydrogen atoms. d2 It is an alkyl group having 1 to 5 carbon atoms. d1 (Integers between 0 and 5.)

[0153] R in the formula d1 and R d2 Examples of alkyl groups having 1 to 5 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, and n-pentyl. The alkyl group having 1 to 5 carbon atoms can be either straight-chain or branched. Preferably, it is an alkyl group having 1 to 3 carbon atoms; more preferably, it is an alkyl group having 1 or 2 carbon atoms; and even more preferably, it is methyl.

[0154] n in the formula d1 It is an integer from 0 to 5, preferably an integer from 0 to 2, more preferably 0 or 1, and even more preferably 0.

[0155] Polystyrene-based elastomers may contain structural units other than those derived from styrene compounds.

[0156] Structural units other than those derived from styrene compounds that can be contained in polystyrene-based elastomers include structural units derived from butadiene, isoprene, maleic acid, and maleic anhydride.

[0157] The structural units derived from butadiene and isoprene described above can be hydrogenated. In the case of hydrogenation, the structural units derived from butadiene are structural units composed of a mixture of ethylene and butene units, and the structural units derived from isoprene are structural units composed of a mixture of ethylene and propylene units.

[0158] As polystyrene-based elastomers, examples include styrene-butadiene-styrene block copolymer (SBS) or its hydride, styrene-isoprene-styrene block copolymer (SIS) or its hydride, and styrene-maleic anhydride copolymer.

[0159] Examples of SBS hydrides include SEBS, which is formed by the complete hydrogenation of carbon-carbon double bonds in butadiene blocks, and SBBS, which is formed by the partial hydrogenation of carbon-carbon double bonds at the 1,2-bond sites in butadiene blocks. It should be noted that complete hydrogenation in SEBS typically refers to a carbon-carbon double bond ratio of 90% or higher relative to the overall carbon-carbon double bond ratio; this can be 95%, 99%, or even 100%. Conversely, the partial hydrogenation rate in SBBS is, for example, 60% to 85% relative to the overall carbon-carbon double bond ratio. That is, SBBS contains carbon-carbon double bonds as reactive groups in its molecular chain. More specifically, SBBS contains structural units represented by formula A: -CH2-CH=CH-CH2- in its molecular chain.

[0160] As a hydrogenated product of SIS, SEPS can be cited as an example, which is produced by hydrogenating the polyisoprene portion of SIS.

[0161] The number-average molecular weight of the elastomer is not particularly limited, but is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and even more preferably 100,000 to 200,000.

[0162] The weight-average molecular weight of the elastomer is not particularly limited, but is preferably 10,000 to 500,000, more preferably 50,000 to 350,000, and even more preferably 100,000 to 200,000.

[0163] (Inorganic filler material)

[0164] The resin composition contains inorganic filler materials.

[0165] The presence of inorganic fillers in the resin composition tends to reduce the thermal expansion coefficient, improve heat resistance and flame retardancy of the cured product.

[0166] The inorganic filler contained in the resin composition may be only one type or two or more types.

[0167] Examples of inorganic filler materials include silica, alumina, titanium dioxide, beryllium oxide, 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, and silicon carbide. Among these, silica and alumina are preferred from the perspectives of low thermal expansion, heat resistance, and flame retardancy.

[0168] The average particle size of the inorganic filler is not particularly limited, but from the viewpoint of dispersibility in the resin composition and adaptability to micro-wires, it is preferably 0.01 μm to 20 μm, more preferably 0.1 μm to 10 μm, and even more preferably 0.5 μm to 5 μm.

[0169] In this disclosure, the average particle size of the inorganic filler material refers to the particle size at which the volume accumulation reaches 50% in the volume-based particle size distribution curve (volume-average particle size, D50). The volume-based particle size distribution curve can be obtained, for example, by laser diffraction scattering.

[0170] The shape of the inorganic filler material is not particularly limited, but it is preferably spherical.

[0171] To improve dispersibility and adhesion to organic components, inorganic fillers can be surface-treated with coupling agents. Examples of coupling agents include silane coupling agents and titanate coupling agents. Silane coupling agents are preferred. Examples of silane coupling agents include aminosilane coupling agents, vinylsilane coupling agents, and epoxysilane coupling agents.

[0172] (Curing accelerator)

[0173] The resin composition may contain a curing accelerator. By including a curing accelerator in the resin composition, there is a tendency to improve the curability of the resin composition, as well as the dielectric properties and heat resistance of the cured product.

[0174] There are no particular restrictions on the type of curing accelerator; it can be selected based on the type of curable resin contained in the resin composition.

[0175] Examples of curing accelerators include acidic catalysts such as p-toluenesulfonic acid; amine compounds such as triethylamine, pyridine, tributylamine, and dicyandiamide; imidazole compounds such as methylimidazole, phenylimidazole, and 1-cyanoethyl-2-phenylimidazole; isocyanate-blocked imidazole compounds such as the addition reaction product of hexamethylene diisocyanate resin and 2-ethyl-4-methylimidazole; tertiary amine compounds; quaternary ammonium compounds; phosphorus compounds such as triphenylphosphine; and dicumyl peroxide and 2,5-dimethyl-2,5-bis(tert-butylperoxide). Organic peroxides such as hexyne-3, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, tert-butylperoxyisopropyl monocarbonate, and 1,3-bis(tert-butylperoxyisopropyl)benzene; inorganic peroxides such as potassium persulfate, sodium persulfate, and ammonium persulfate; azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylpentanitrile), and 2,2'-azobis(4-methoxy-2'-dimethylpentanitrile); and carboxylates such as manganese, cobalt, and zinc.

[0176] When the resin composition contains a curable resin with free radical polymerization properties, it is preferable to include a free radical polymerization initiator as a curing accelerator. Examples of free radical polymerization initiators include organic peroxides, inorganic peroxides, and azo compounds. From the viewpoint of improving curability, organic peroxides are preferred.

[0177] The resin composition may contain only one type of curing accelerator or two or more types.

[0178] When the resin composition contains a curing accelerator, its content is not particularly limited, but is preferably 0.1 to 15 parts by mass relative to the total amount of resin components (100 parts by mass), more preferably 1 to 10 parts by mass, and even more preferably 4 to 8 parts by mass.

[0179] When the content of the curing accelerator is greater than or equal to 0.1 parts by weight, there is a tendency to obtain a sufficient curing promotion effect. When the content of the curing accelerator is less than or equal to 15 parts by weight, there is a tendency for the storage stability of the resin composition to become better.

[0180] When the resin composition contains a free radical polymerization initiator as a curing accelerator, its content is not particularly limited, but is preferably 0.05 to 7 parts by mass relative to the total amount of resin components (100 parts by mass), more preferably 0.5 to 5 parts by mass, and even more preferably 2 to 4 parts by mass.

[0181] When the content of the free radical polymerization initiator is greater than or equal to the lower limit mentioned above, there is a tendency to obtain a sufficient curing promotion effect. Conversely, when the content of the free radical polymerization initiator is less than or equal to the upper limit mentioned above, there is a tendency for better storage stability.

[0182] (Other ingredients)

[0183] The resin composition may include components other than those listed above (other components) as needed. Examples of other components include flame retardants, antioxidants, heat stabilizers, antistatic agents, ultraviolet absorbers, colorants, lubricants, etc.

[0184] The resin composition may contain only one other component or two or more components.

[0185] (Content of essential components)

[0186] There are no particular restrictions on the content of the essential components (curing resin, elastomer and inorganic filler) in the resin composition, and they can be selected according to the application of the resin film, the desired properties, etc.

[0187] From the viewpoint of imparting sufficient curability to the resin film, the content of curable resin 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 even more preferably greater than or equal to 20% by volume.

[0188] From the viewpoint of balancing with other components, the content of curable resin 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 even more preferably less than or equal to 30% by volume.

[0189] From the viewpoint of improving the operability of the resin film, the content of elastomer contained in the resin composition is preferably greater than or equal to 5% by volume, more preferably greater than or equal to 8% by volume, and even more preferably greater than or equal to 10% by volume.

[0190] From the viewpoint of balancing with other components, the content of elastomer in the resin composition is preferably less than or equal to 30% by volume, more preferably less than or equal to 25% by volume, and even more preferably less than or equal to 20% by volume.

[0191] From the perspective of reducing the thermal expansion coefficient of the resin film, improving heat resistance, and improving flame retardancy, the content of inorganic filler material in the resin composition is preferably greater than or equal to 40% by volume, more preferably greater than or equal to 45% by volume, and even more preferably greater than or equal to 50% by volume.

[0192] From the perspective of balancing with other components, the content of inorganic filler in the resin composition is preferably less than or equal to 80% by volume, more preferably less than or equal to 75% by volume, and even more preferably less than or equal to 70% by volume.

[0193] From the viewpoint of balancing adaptability to grinding and operability of resin sheets, the proportion of elastomer in the resin component of the resin composition is preferably 20% to 50% by volume.

[0194] The content of each of the above components is based on the content of solid components contained in the resin composition.

[0195] In this disclosure, resin component refers to the component of the solid components contained in the resin composition that is equivalent to organic matter.

[0196] (Various properties of resin films)

[0197] There are no particular limitations on the thickness of the resin film; it can be selected based on the intended use of the resin film. For example, the thickness of the resin film can be greater than or equal to 10 μm, greater than or equal to 50 μm, greater than or equal to 80 μm, or greater than or equal to 100 μm.

[0198] The thickness of the resin film can be, for example, less than or equal to 1,000 μm, less than or equal to 700 μm, or less than or equal to 500 μm.

[0199] From the viewpoint of the operability of the resin membrane, the resin membrane is preferably disposed on the support.

[0200] There are no particular restrictions on the material of the support; examples include resin, metal, and paper. If necessary, the surface of the support in contact with the resin film can be treated for demolding.

[0201] The thickness of the support is not particularly limited, but from the point of view of operability and economy, it is preferably 10μm to 150μm, more preferably 20μm to 100μm, and even more preferably 25μm to 50μm.

[0202] A resin film disposed on a support can be made, for example, by coating a resin varnish obtained by adding an organic solvent to a resin composition onto the support and drying it to remove the organic solvent.

[0203] The content of organic solvent in the dried resin film is preferably less than or equal to 2% by mass relative to the total amount of the resin film (100% by mass), more preferably less than or equal to 1% by mass, even more preferably less than or equal to 0.5% by mass, and may also be 0% by mass.

[0204] If the content of organic solvent in the resin film is within the above range, the volatilization of organic solvent during heat curing can be sufficiently suppressed.

[0205] A resin film can also be a state in which at least a portion of the curing components contained in the resin film have reacted.

[0206] The resin film can also have a protective film disposed on its surface. For example, the resin film can have a support disposed on one side and a protective film disposed on the other side.

[0207] There are no particular restrictions on the material of the protective film; examples include resin, metal, and paper. If necessary, the surface of the protective film in contact with the resin film can be treated for release.

[0208] The thickness of the protective film is not particularly limited, but from the point of view of operability and economy, it is preferably 10μm to 150μm, more preferably 20μm to 100μm, and even more preferably 25μm to 50μm.

[0209] The applications of the resin film disclosed herein are not particularly limited. Examples of preferred applications include the formation of insulating layers on printed wiring boards and the sealing of semiconductor components contained in semiconductor packages. The resin film disclosed herein exhibits excellent adaptability to grinding processes and is therefore suitable for applications involving grinding.

[0210] An example of grinding treatment performed on the resin film of this disclosure is illustrated with reference to the accompanying drawings.

[0211] First, such as Figure 1 As shown in (A), a substrate 20 with protrusions 10 is prepared. Next, as... Figure 1 As shown in (B), the resin film 30 is disposed on the substrate 20 by embedding the protrusion 10. Next, as... Figure 1 As shown in (C), the resin film 30 is cured to obtain a cured resin film 40. Next, as... Figure 1 As shown in (D), the surface of the cured resin film 40 is ground to expose the top of the protrusion 10.

[0212] As Figure 1 Examples of the protrusion 10 shown include metal pillars, metal bumps, solder balls, wiring patterns, semiconductor chips, etc. The protrusion 10 can also be a raised portion between recesses in a substrate having recesses such as grooves.

[0213] The spacing between adjacent protrusions 10 can be selected, for example, from 10 μm to 200 μm. The height of the protrusions 10 can be selected, for example, from 10 μm to 200 μm.

[0214] Printed wiring board

[0215] The printed wiring board disclosed herein includes a cured form of the aforementioned resin film. The cured resin film may, for example, be an insulating layer disposed on a substrate included in the printed wiring board. The printed wiring board may also be a multilayer printed wiring board.

[0216] The following describes an example of a method for manufacturing printed wiring boards using the resin film disclosed herein.

[0217] First, a resin film is deposited on the substrate. The resin film can be deposited while the resin film is being pressurized and heated. The resin film can be deposited on only one side of the substrate or on both sides.

[0218] As a substrate for a printed wiring board, a substrate (circuit board) with a conductor layer forming a circuit pattern on its surface can be used. The substrate can be selected from known substrates such as glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, and thermosetting polyphenylene ether substrates without particular limitation.

[0219] Next, the resin film disposed on the substrate is cured to form an insulating layer. The curing conditions are set taking into account the components contained in the resin film.

[0220] The insulating layer formed by curing the resin film can be subjected to hole-making, roughening, grinding and other treatments as needed.

[0221] A conductor layer can also be further disposed on the insulating layer formed by curing the resin film. The conductor layer can be disposed by known methods such as plating.

[0222] Semiconductor Packaging

[0223] The semiconductor package disclosed herein includes a cured resin film as described above. The cured resin film may, for example, be a seal disposed around an electronic component mounted on a substrate.

[0224] The following describes an example of a method for manufacturing a semiconductor package using the resin film disclosed herein. First, a resin film is placed on an electronic component, such as a semiconductor chip, disposed on a substrate. Next, the electronic component is embedded in the resin film by heating and pressurizing it as needed. Then, by curing the resin film with the embedded electronic component, a semiconductor package in which the electronic component is sealed by the cured resin film can be manufactured.

[0225] Example

[0226] The following examples illustrate this implementation method. However, this implementation method is not limited to the following examples.

[0227] (Preparation of resin film)

[0228] The components shown in Table 1 were mixed with a solvent (toluene) to prepare a resin varnish with a solids content of approximately 50% by mass. Unless otherwise specified, the amounts of the components listed in Table 1 are expressed in "volume %".

[0229] Next, a resin varnish is applied to one side of the PET film to form a resin varnish layer. Then, it is heated and dried at 105°C for 5 minutes, thereby evaporating the solvent contained in the resin varnish layer, resulting in a resin composition layer with a PET film on one side.

[0230] Next, a resin composition layer with a PET film on one side is overlapped with a resin composition layer with a PET film on the other side. In this state, the resin composition layers are laminated using a vacuum laminator at a temperature of 100°C and a pressure time of 5 seconds, thereby obtaining a resin film with PET films on both sides.

[0231] (Curing treatment of resin film)

[0232] The PET film of the resin film obtained above was peeled off. Next, a 12μm thick low-profile copper foil (manufactured by Mitsui Metals & Mining Co., Ltd., trade name "3EC-VLP-12") was placed on both sides of the resin film with the S-side facing the resin film. In this state, the low-profile copper foil and the resin film were laminated using a vacuum laminator to obtain a laminate. The lamination conditions were set as follows: temperature 100°C, vacuum time 30 seconds, pressurization time 20 seconds, and pressure 0.1MPa. The laminate was then cured by heating at 180°C for 1 hour to obtain a cured resin film (thickness: 120μm).

[0233] (Determination of energy storage modulus)

[0234] Test pieces with a width of 0.4 mm, a length of 20 mm, and a thickness of 0.12 mm were made from the cured resin film obtained by curing treatment.

[0235] The storage modulus of the test specimen was determined by dynamic viscoelasticity measurement. The measurement was performed using a Rheogel E4000 (UBM) under tensile conditions, a frequency of 10 Hz, a sinusoidal wave, a load of 25 g, and a strain of 5 μm. The results of the storage modulus measurement at 25 °C are shown in Table 1.

[0236] (Evaluation of grindability)

[0237] The cured resin film obtained by curing was laminated onto a 12-inch silicon wafer, and the following grinding test was performed.

[0238] Device: DAG-810 manufactured by DISCO

[0239] Grinding stone: GFCP-SD4000-VBD05-150 (#320, #4000)

[0240] Grinding conditions: plunge grinding mode, machining speed 0.2 μm / s, rotational speed 2000 rpm (times / minute).

[0241] Grinding process: Use a #320 grinding stone to coarsely grind 50μm of the cured material, then use a #4000 grinding stone to grind 20μm of the cured material.

[0242] Visually inspect the appearance of the cured material after grinding and evaluate it according to the following criteria. The results are shown in Table 1.

[0243] The ground surface has a glossy finish…○

[0244] The surface after grinding lacks luster…×

[0245] The maximum current value during the grinding test was measured as an indicator of the grinding load. The results are shown in Table 1.

[0246] [Table 1]

[0247]

[0248] The details of the components listed in Table 1 are as follows.

[0249] Curing Resin 1: An aromatic bismaleimide resin containing an indane ring, represented by general formula (A1-4-1), with a number average molecular weight of 1,300, and solid at 25°C.

[0250] Curable Resin 2: A polybutadiene homopolymer containing 1,2-vinyl groups, with a vinyl content of ≥85%, liquid at 25°C, and a number-average molecular weight of 1,200.

[0251] Curing resin 3: Nonene glycol dimethacrylate, liquid at 25°C, molecular weight: 296.4

[0252] Elastomer 1: SEBS

[0253] Elastomer 2: SBBS, weight average molecular weight: 100,000

[0254] Inorganic filler material 1: Silica particles with a volume average particle size of 2.4 μm

[0255] Inorganic filler material 2: Silica particles with a volume average particle size of 1.0 μm

[0256] Coupling agent: 3-methacryloyloxypropyltrimethoxysilane

[0257] Curing accelerator 1: 1,3-Di(tert-butylperoxyisopropyl)benzene

[0258] Curing accelerator 2: Imidazole-based curing accelerator

[0259] As shown in Table 1, the resin films of the examples with a storage modulus greater than or equal to 4 GPa in the cured state exhibited better surface finish after grinding compared to the resin films of the comparative examples with a storage modulus less than 4 GPa in the cured state. Furthermore, the maximum current value in the tests was also lower in the examples than in the comparative examples. These results indicate that the resin films with a storage modulus greater than or equal to 4 GPa in the cured state demonstrate excellent adaptability to grinding.

[0260] The entire contents of Japanese Patent Application No. 2024-013688 are incorporated herein by reference. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent that each document, patent application, and technical standard is specifically described and incorporated herein by reference.

Claims

1. A resin membrane comprising a resin composition containing a curable resin, an elastomer, and an inorganic filler, wherein the storage modulus of the resin membrane at 25°C, measured in the cured state, is greater than or equal to 4 GPa.

2. The resin film according to claim 1, wherein, The energy storage modulus is less than or equal to 10 GPa.

3. The resin film according to claim 1, wherein, The curable resin comprises a curable resin that is free radical polymerizable.

4. The resin film according to claim 1, wherein, The inorganic filler material contains 50% to 70% by volume.

5. The resin film according to any one of claims 1 to 4, which is used as a sealing material for semiconductor packaging.

6. The resin film according to any one of claims 1 to 4, used to form an insulating layer of a printed wiring board.

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

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

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