resin sheet

Abstract

The present invention provides a resin sheet formed from a resin composition containing (A) a thermosetting component and (C) a thermally conductive filler, wherein the (A) thermosetting component contains a maleimide resin, and the thermal diffusivity of the resin sheet after thermal curing is 1.0×10 ‑6 m 2 / s or more, and when observing a region (P1) in a cross section (P) of the resin sheet, the following mathematical formula (F1) is satisfied: the cross section (P) is a cross section taken along a direction perpendicular to the surface of the resin sheet; the region (P1) is a region enclosed by a square having a side length four times the thickness of the resin sheet and including both surfaces of the resin sheet; 0.25 ≤ Ld / Lt ≤ 1... (F1). Ld: The length of the thermally conductive filler (C) having the largest cross-sectional diameter in the perpendicular direction in the perpendicular direction; Lt: The length of the resin sheet in the perpendicular direction.

Description

Technical Field

[0001] The present invention relates to a resin sheet. Background Art

[0002] The addition of a high thermal conductivity material such as alumina to resin sheets for power semiconductors has been studied. Patent Document 1 proposes the use of a resin sheet formed of an epoxy resin composition containing an alumina filler in a power semiconductor device.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-160440 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] However, the resin composition described in Patent Document 1 is not considered to have sufficient heat resistance when used in power semiconductor devices that are expected to operate at high temperatures exceeding 200°C. Furthermore, further improving thermal conductivity and firmly bonding the resin sheet to the adherend remain challenges.

[0008] An object of the present invention is to provide a resin sheet capable of improving heat resistance, thermal conductivity, and adhesiveness after thermal curing.

[0009] Solutions to the Problem

[0010] A resin sheet according to one embodiment of the present invention is formed from a resin composition containing (A) a thermosetting component and (C) a thermally conductive filler, wherein the thermosetting component (A) contains a maleimide resin, and the thermal diffusivity of the resin sheet after thermal curing is 1.0×10 -6 m 2 / s or more, when observing the area (P1) in the cross-section (P) of the above-mentioned resin sheet, the condition represented by the following mathematical formula (F1) is satisfied, wherein the cross-section (P) is a cross-section cut in a direction perpendicular to the surface of the above-mentioned resin sheet, and the area (P1) is an area surrounded by a square having a side length of 4 times the thickness of the above-mentioned resin sheet and including two surfaces of the above-mentioned resin sheet.

[0011] 0.25≤Ld / Lt≤1···(F1)

[0012] Ld: The length of the thermally conductive filler (C) with the largest cross-sectional diameter in the vertical direction.

[0013] Lt: Length of the resin sheet in the vertical direction

[0014] In one embodiment of the resin sheet of the present invention, the thermosetting component (A) preferably contains a first maleimide resin (A1), wherein the first maleimide resin (A1) is a maleimide resin that is solid at 25°C and has two or more maleimide groups in one molecule, and the bonding group linking at least one pair of two maleimide groups has four or more methylene groups in the main chain.

[0015] In the resin sheet of one embodiment of the present invention, it is preferred that the (A) thermosetting component further contain (A4) a compound having a triazine skeleton.

[0016] In the resin sheet of one embodiment of the present invention, it is preferred that the compound (A4) having a triazine skeleton is an imidazole compound having a triazine skeleton.

[0017] In the resin sheet according to one embodiment of the present invention, it is preferred that the (A) thermosetting component further contain (A5) an allyl resin.

[0018] In the resin sheet according to one embodiment of the present invention, it is preferred that the resin composition further contain (C1) boron nitride particles.

[0019] In the resin sheet according to one embodiment of the present invention, it is preferred that the resin composition further contain (C2) alumina particles.

[0020] In the resin sheet of one embodiment of the present invention, the total content of the (C1) boron nitride particles and the (C2) aluminum oxide particles is preferably 78.5% by mass or more based on the total solid content of the resin composition.

[0021] The resin sheet according to one embodiment of the present invention is preferably used for sealing a semiconductor element, or for being interposed between the semiconductor element and other electronic components.

[0022] The resin sheet according to one embodiment of the present invention is preferably used to be interposed between a radiator and an electronic component.

[0023] The resin sheet according to one embodiment of the present invention is preferably used to seal a semiconductor element using a compound semiconductor, or to be interposed between a semiconductor element using the compound semiconductor and other electronic components.

[0024] In the resin sheet according to one embodiment of the present invention, the resin sheet is preferably a coating film of the resin composition.

[0025] According to one embodiment of the present invention, a resin sheet capable of improving heat resistance, thermal conductivity, and adhesiveness after thermal curing and a method for producing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1This is a schematic diagram showing a cross section of the resin sheet according to the present embodiment.

[0027] Figure 2 It is a schematic cross-sectional view of the laminated body of this embodiment.

[0028] Figure 3 This is a scanning electron microscope (SEM) photograph showing a cross section of the resin sheet obtained in Example 4.

[0029] Explanation of symbols

[0030] 1...Laminated body

[0031] 2…First peeling material

[0032] 3…resin sheet

[0033] 4…Second peeling material DETAILED DESCRIPTION

[0034] [Resin composition]

[0035] First, the resin composition for forming the resin sheet of the present embodiment will be described.

[0036] The resin composition of this embodiment contains (A) a thermosetting component. The thermosetting component (A) of this embodiment contains a maleimide resin. In addition, the thermosetting component (A) of this embodiment preferably contains (A1) a first maleimide resin.

[0037] ((A) Thermosetting component)

[0038] The (A) thermosetting component (hereinafter also referred to as "component (A)") has the property of forming a three-dimensional network when heated, thereby firmly adhering to the adherend. As described above, the (A) thermosetting component in this embodiment preferably contains the (A1) first maleimide resin (hereinafter also referred to as "component (A1)").

[0039] Maleimide resin

[0040] The maleimide resin in this embodiment is not particularly limited as long as it contains two or more maleimide groups in one molecule. By including the maleimide resin in the resin composition of this embodiment, the heat resistance of the resin sheet of this embodiment after thermal curing is improved.

[0041] Examples of the maleimide resin in the present embodiment include (A1) a first maleimide resin, (A2) a second maleimide resin, and (A3) a third maleimide resin.

[0042] (A1) First maleimide resin

[0043] The first maleimide resin (A1) in the present embodiment has two or more maleimide groups in one molecule, and the bonding group linking at least one pair of two maleimide groups has four or more methylene groups in the main chain.

[0044] Here, from the perspective of the flexibility of the cured product, the bonding group linking the two maleimide groups preferably has 6 or more methylene groups in the main chain, more preferably 8 or more methylene groups in the main chain, and particularly preferably 10 or more methylene groups in the main chain. Furthermore, these methylene groups are more preferably linked to form an alkylene group having 4 or more carbon atoms. In this alkylene group, at least one -CH2- group may be replaced by -CH2-O- or -O-CH2-.

[0045] In addition, from the viewpoint of the flexibility of cured product, the bonding group linking two maleimide groups preferably has one or more side chains. As the side chain, alkyl and alkoxy groups etc. can be listed. Further, when there are two or more side chains, the side chains can also be bonded to each other to form an alicyclic structure.

[0046] In addition, the first maleimide resin (A1) in the present embodiment needs to be solid at a temperature of 25°C. It can be inferred that by making the first maleimide resin (A1) solid at a temperature of 25°C, the (A1) component acts not only as a thermosetting component but also as an adhesive component. Since the (A1) component is easily softened, the followability of the resin sheet to the concavo-convex surface of the adherend before curing can be improved by replacing the adhesive component with the (A1) component, thereby achieving an increase in the amount of thermally conductive filler while maintaining adhesion. Therefore, by using the (A1) component, the thermal conductivity and adhesion of the resin sheet can be improved at the same time. In addition, the compatibility of the (A1) component is also high when other maleimide resins are used.

[0047] From the viewpoint of flexibility and heat resistance of the cured product, the first maleimide resin (A1) in the present embodiment is preferably represented by the following general formula (A1).

[0048] [Chemical Formula 1]

[0049]

[0050] In the above general formula (A1), n 11 is an integer greater than or equal to 0, preferably an integer greater than or equal to 1 and less than or equal to 10, and more preferably an integer greater than or equal to 1 and less than or equal to 5. 11 The average value of is preferably 0.5 or more and 5 or less, more preferably 1 or more and 2 or less.

[0051] L 11 and L 12Each independently represents a substituted or unsubstituted alkylene group having 4 or more carbon atoms, wherein at least one -CH2- in the alkylene group is optionally replaced by -CH2-O- or -O-CH2-. From the perspective of the flexibility of the cured product, the number of carbon atoms in the alkylene group is preferably 6 or more, more preferably 8 or more, and particularly preferably 10 or more and 30 or less. In addition, when the hydrogen atoms of the alkylene group are substituted, the substituent is an alkyl group having 1 or more and 14 or less carbon atoms, or an alkoxy group having 1 or more and 14 or less carbon atoms. Furthermore, these substituents may be bonded to each other to form an alicyclic structure or a heterocyclic structure.

[0052] X 11 Each independently represents a group not having a substituted or unsubstituted alkylene group having 4 or more carbon atoms (including a group in which at least one -CH2- is replaced by -CH2-O- or -O-CH2-), and is more preferably a divalent group having a phthalimide group. It should be noted that the phthalimide group also includes a group derived from phthalimide. As X 11 Specific examples include groups represented by the following structural formula (A1-1).

[0053] [Chemical Formula 2]

[0054]

[0055] Specific examples of the maleimide resin represented by the general formula (A1) in this embodiment include compounds represented by the following general formula (A1-1-1). This compound is solid at a temperature of 25°C.

[0056] [Chemical Formula 3]

[0057]

[0058] In the above general formula (A1-1-1), n 11 It is an integer of 1 to 5.

[0059] Examples of products of the maleimide resin represented by the general formula (A1-1-1) include "SLK-3000" manufactured by Shin-Etsu Chemical Co., Ltd.

[0060] In this embodiment, the content of component (A1) in the maleimide resin is preferably 10% by mass or more, more preferably 17.5% by mass or more, and particularly preferably 42.5% by mass or more, based on the total solid content of the maleimide resin (i.e., when the amount of non-volatile components of the maleimide resin excluding the solvent is set to 100% by mass). By adjusting the content of component (A1) in the maleimide resin to this range, the amount of thermally conductive filler in the resin sheet can be further increased. Based on the total solid content of the maleimide resin, the content of component (A1) in the maleimide resin is preferably 100% by mass or less, more preferably 75% by mass or less, and even more preferably 60% by mass or less.

[0061] From the same viewpoint, based on the total amount of solids in the resin composition (i.e., when the total amount of non-volatile components in the resin composition excluding the solvent is taken as 100% by mass), the content of component (A1) in the maleimide resin is preferably 2.5% by mass or more, more preferably 4% by mass or more, and even more preferably 6% by mass or more. Based on the total amount of solids in the resin composition, the content of component (A1) in the maleimide resin is preferably 15% by mass or less, and more preferably 12% by mass or less.

[0062] (A2) Second maleimide resin

[0063] From the viewpoint of increasing the storage modulus E' of the cured product of the resin sheet at 250°C, the (A) thermosetting component contained in the resin composition in this embodiment may further contain (A2) a second maleimide resin having a chemical structure different from that of the above-mentioned (A1) first maleimide resin. The (A2) second maleimide resin in this embodiment (hereinafter also referred to as "(A2) component") is not particularly limited as long as it is a maleimide resin having a chemical structure different from that of the above-mentioned (A1) first maleimide resin and containing two or more maleimide groups in one molecule. That is, the (A2) second maleimide resin is a maleimide resin having two or more maleimide groups in one molecule, and the bonding groups connecting any two maleimide groups do not have four or more methylene groups on the main chain. Since the resin sheet contains the component (A2), the cohesiveness of the resin sheet after curing is improved, and thus it is possible to prevent a decrease in adhesiveness due to cohesive failure of the resin sheet after curing.

[0064] From the viewpoint of heat resistance, the second maleimide resin (A2) in this embodiment preferably comprises, for example, a benzene ring, and more preferably comprises a structure in which a maleimide group is linked to the benzene ring. In addition, the maleimide compound preferably comprises a structure in which two or more maleimide groups are linked to the benzene ring.

[0065] The second maleimide resin (A2) in the present embodiment is preferably a maleimide resin containing two or more maleimide groups and one or more biphenyl skeletons in one molecule (hereinafter also simply referred to as "biphenyl maleimide resin").

[0066] From the viewpoint of heat resistance and adhesiveness, the second maleimide resin (A2) in the present embodiment is preferably represented by the following general formula (1).

[0067] [Chemical Formula 4]

[0068]

[0069] In the above general formula (1), k is an integer greater than or equal to 1, and the average value of k is preferably greater than or equal to 1 and less than or equal to 10, more preferably greater than or equal to 1 and less than or equal to 5, and even more preferably greater than or equal to 1 and less than or equal to 3; m1 and m2 are each independently an integer greater than or equal to 1 and less than or equal to 2, more preferably 1, wherein the sum of m1 and m2 is 3 or less; n1 and n2 are each independently an integer greater than or equal to 0 and less than or equal to 4, preferably an integer greater than or equal to 0 and less than or equal to 2, and more preferably 0; R 1 and R 2 Each independently represents an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably a methyl group; 1 Same or different from each other; multiple R 2 Same as or different from each other.

[0070] Specific examples of the maleimide resin represented by the general formula (1) in the present embodiment include compounds represented by the following general formula (2) or the following general formula (3).

[0071] [Chemical Formula 5]

[0072]

[0073] [Chemical Formula 6]

[0074]

[0075] In the above general formulas (2) and (3), k is the same as k in the above general formula (1). In the above general formula (2), n1, n2, R 1 and R 2 With the above general formula (1) n1, n2, R 1 and R 2 same.

[0076] Examples of products of the maleimide resin represented by the general formula (3) include "MIR-3000-70" manufactured by Nippon Kayaku Co., Ltd.

[0077] Furthermore, the second maleimide resin (A2) in this embodiment is preferably a maleimide resin containing two or more maleimide groups and two or more phenylene groups in one molecule. From the perspective of improving solubility in solvents and sheet forming properties, it is preferred that the phenylene group has a substituent. Examples of the substituent include alkyl groups such as methyl and ethyl groups, and alkylene groups.

[0078] Furthermore, from the viewpoint of sheet forming properties, the second maleimide resin (A2) in the present embodiment is preferably a maleimide resin having an ether bond between a maleimide group and a phenylene group.

[0079] The maleimide resin containing two or more maleimide groups and two or more phenylene groups in one molecule is represented by the following general formula (4), for example.

[0080] [Chemical Formula 7]

[0081]

[0082] In the above general formula (4), R 3 ~R 6 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, L 1 is an alkylene group having 1 to 3 carbon atoms, L 2 and L 3 Each independently represents an alkylene group having 1 to 2 carbon atoms or an arylene group having 6 to 10 carbon atoms, and p and q each independently represent 0 or 1. 1 , L 2 and L 3 The total number of carbon atoms of the alkylene group is 3 or less.

[0083] The maleimide resin represented by the general formula (4) in the present embodiment is specifically represented by, for example, the following general formula (5) or the following general formula (6).

[0084] [Chemical Formula 8]

[0085]

[0086] [Chemical Formula 9]

[0087]

[0088] In the above general formulas (5) and (6), L 1 It is an alkylene group having 1 to 3 carbon atoms.

[0089] In the above general formula (5), R 3 ~R 6 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0090] (A3) The third maleimide resin

[0091] To facilitate maintaining the sheet strength after thermosetting, the thermosetting component (A) contained in the resin composition of this embodiment may further contain a third maleimide resin (A3) having different properties from the first maleimide resin (A1) described above. The third maleimide resin (A3) in this embodiment (hereinafter referred to as "component (A3)") shares the same chemical structure as the first maleimide resin (A1) described above, but has different properties and is liquid at 25°C. The inclusion of component (A3) imparts flexibility to the cured resin sheet, suppressing embrittlement and improving strength such as impact resistance.

[0092] Specifically, the third maleimide resin (A3) in this embodiment refers to a spacer-containing maleimide resin having two or more maleimide groups per molecule, a bonding group linking at least one pair of two maleimide groups, and four or more methylene groups in the main chain, and is liquid at 25° C. Using a spacer-containing maleimide resin as the third maleimide resin (A3) facilitates maintaining the sheet strength of the resin sheet after thermal curing.

[0093] From the perspective of the flexibility of the resin sheet, the bonding group linking the two maleimide groups preferably has six or more methylene groups in the main chain, more preferably eight or more methylene groups in the main chain, and particularly preferably ten or more methylene groups in the main chain. Furthermore, these methylene groups are more preferably linked to form an alkylene group having four or more carbon atoms. In this alkylene group, at least one -CH2- group may be replaced by -CH2-O- or -O-CH2-.

[0094] In addition, from the perspective of the flexibility of the resin sheet, the bonding group connecting the two maleimide groups preferably has one or more side chains. Examples of such side chains include alkyl groups and alkoxy groups. Furthermore, when two or more side chains are included, the side chains may be bonded to form an alicyclic structure or a heterocyclic structure.

[0095] From the viewpoint of the flexibility and heat resistance of the resin sheet, the spacer-containing maleimide resin in the present embodiment is preferably represented by the following general formula (7).

[0096] [Chemical Formula 10]

[0097]

[0098] In the general formula (7), n is an integer of 0 or greater, preferably an integer of 1 or greater and 10 or less, and more preferably an integer of 1 or greater and 5 or less. The average value of n is preferably 0.5 or greater and 5 or less, and more preferably 1 or greater and 2 or less.

[0099] L 4 and L 5 Each independently represents a substituted or unsubstituted alkylene group having 4 or more carbon atoms, in which at least one -CH2- group may be replaced by -CH2-O- or -O-CH2-. From the perspective of the flexibility of the resin sheet, the number of carbon atoms in the alkylene group is preferably 6 or more, more preferably 8 or more, and particularly preferably 10 or more and 30 or less. Furthermore, when a hydrogen atom in the alkylene group is substituted, the substituent is an alkyl group having 1 or more and 10 or less carbon atoms, or an alkoxy group having 1 or more and 10 or less carbon atoms. Furthermore, these substituents may be bonded to each other to form an alicyclic structure.

[0100] Each of X is independently a group that does not have a substituted or unsubstituted alkylene group having 4 or more carbon atoms (including a group in which at least one -CH2- is replaced by -CH2-O- or -O-CH2-), and is more preferably a divalent group having a phthalimide group. It should be noted that the phthalimide group also includes a group derived from phthalimide. Specific examples of X include: groups represented by the following structural formula (7-1) or the following general formula (7-2).

[0101] [Chemical Formula 11]

[0102]

[0103] In the above general formula (7-2), Y 1 and Y 2 Each is independently hydrogen, methyl or ethyl, preferably methyl.

[0104] Specific examples of the maleimide resin represented by the general formula (7) in the present embodiment include compounds represented by the following general formula (7-1-1) or the following general formula (7-2-1).

[0105] [Chemical Formula 12]

[0106]

[0107] In the general formulae (7-1-1) and (7-2-1), n ​​is an integer of 1 to 5. The average value of n is 1 to 2.

[0108] Examples of products of the maleimide resin represented by the general formula (7-1-1) include "BMI-1500" manufactured by Designer Molecules and "SLK-1500" manufactured by Shin-Etsu Chemical Co., Ltd.

[0109] As a product of the maleimide resin represented by the said general formula (7-2-1), "BMI-1700" manufactured by Designer Molecules etc. are mentioned.

[0110] When components (A2) and (A3) are used in the present embodiment, the ratio of the content of components (A2) to (A3) in the maleimide resin is preferably 25:75 to 75:25, more preferably 30:70 to 70:30, and particularly preferably 40:60 to 60:40, based on mass, from the viewpoint of achieving a balance between the cohesiveness and flexibility of the cured resin sheet. By adjusting the content ratio of components (A2) to (A3) in the maleimide resin to be within this range, the flexibility of the resin sheet of the present embodiment can be further improved.

[0111] In the present embodiment, the content of the maleimide resin in component (A) (the total of components (A1) to (A3)) is preferably 60% by mass or more, more preferably 65% ​​by mass or more, and particularly preferably 70% by mass or more, based on the total amount of the solid content of component (A) (i.e., when the amount of the non-volatile component of component (A) excluding the solvent is set to 100% by mass). Based on the total amount of the solid content of component (A), the content of the maleimide resin in component (A) is preferably 97% by mass or less, more preferably 95% by mass or less, and further preferably 92.5% by mass or less. By setting the content of the maleimide resin in component (A) within such a range, the heat resistance of the resin sheet of the present embodiment after curing can be further improved.

[0112] (A4) Compounds having a triazine skeleton

[0113] From the viewpoint of improving the peel strength after thermal curing of the resin sheet, the resin composition of the present embodiment preferably contains a compound having a triazine skeleton (A4). As the compound having a triazine skeleton (hereinafter, also referred to as "(A4) component") as (A4) in the present embodiment, there is no particular limitation as long as it is a compound containing a triazine skeleton. From the viewpoint of promoting the polymerization reaction of the maleimide resin, taking into account the low temperature at which the thermal curing reaction of the resin sheet is carried out and the peel strength after thermal curing, the (A4) component is preferably a compound as described below. That is, the (A4) component is preferably a compound having a basic group and a triazine skeleton, more preferably a compound having a nitrogen-containing heterocycle and a triazine skeleton, and further preferably an imidazole compound having a triazine skeleton.

[0114] The imidazole compound having a triazine skeleton in the present embodiment is not particularly limited as long as it contains a triazine skeleton and an imidazole group and promotes the polymerization reaction of the maleimide resin.

[0115] Examples of the imidazole compound having a triazine skeleton in the present embodiment include a compound represented by the following general formula (A4′) (hereinafter, also simply referred to as “component (A4′)”).

[0116] [Chemical Formula 13]

[0117]

[0118] In the above general formula (A4'), R 41 and R 42 Each is independently a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a hydroxymethyl group, or a phenyl group, preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 43 is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, a phenyl group, or an allyl group, preferably an alkyl group having 1 to 10 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. 41 It is an alkylene group having 1 to 5 carbon atoms, preferably an alkylene group having 2 to 4 carbon atoms, and more preferably an ethylene group.

[0119] Specific examples of the component (A4′) in the present embodiment include 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine, 2,4-diamino-6-[2-(2-ethyl-4-methyl-1-imidazolyl)ethyl]-1,3,5-triazine, and 2,4-diamino-6-[2-(2-undecyl-1-imidazolyl)ethyl]-1,3,5-triazine. Among these compounds, 2,4-diamino-6-[2-(2-methyl-1-imidazolyl)ethyl]-1,3,5-triazine or 2,4-diamino-6-[2-(2-ethyl-4-methyl-1-imidazolyl)ethyl]-1,3,5-triazine is preferred from the viewpoints of the peel strength of the resin sheet and the reaction temperature.

[0120] In this embodiment, the content of the compound (A4) having a triazine skeleton in the resin composition is preferably 0.05% by mass or greater, more preferably 0.1% by mass or greater, based on the total solids content of the resin composition (i.e., when the total non-volatile content of the resin composition excluding the solvent is taken as 100% by mass). Furthermore, the upper limit of the content of the compound (A4) having a triazine skeleton is preferably 3% by mass or less, more preferably 2% by mass or less.

[0121] When the content of the compound having a triazine skeleton (A4) is within the above range, the peel strength of the resin sheet can be further increased or the reaction temperature can be further lowered.

[0122] In the present embodiment, the compound (A4) having a triazine skeleton in the resin composition may be used alone or in combination of two or more.

[0123] (A5) Allyl resin

[0124] The (A) thermosetting component contained in the resin composition in this embodiment preferably further contains (A5) allyl resin. (A5) Allyl resin (hereinafter, also referred to as "(A5) component") is preferably liquid at room temperature. By making the (A) thermosetting component contain an allyl resin, it is easier to reduce the reaction temperature of the resin sheet of this embodiment while improving the peel strength of the resin sheet after curing. In addition, by containing (A5) allyl resin, the complex viscosity η of the resin sheet can be appropriately adjusted to ensure the fluidity of the resin sheet when applied to the adherend, while achieving further improvement in the heat resistance of the resin sheet after curing.

[0125] In the present embodiment, the mass ratio of the maleimide resin to the allyl resin (A5) (maleimide resin / (A5) component) is preferably 1.5 or greater, more preferably 3 or greater. The upper limit of the mass ratio (maleimide resin / (A5) component) may be, for example, 50 or less, preferably 25 or less, more preferably 15 or less.

[0126] When the mass ratio (maleimide resin / component (A5)) is within the above range, the heat resistance of the resin sheet can be improved.

[0127] Furthermore, when the mass ratio (maleimide resin / component (A5)) is within the above range, bleeding of the allyl resin from the resin sheet can be suppressed.

[0128] The allyl resin (A5) in the present embodiment is not particularly limited as long as it is a resin having an allyl group. The allyl resin (A5) in the present embodiment is preferably an allyl resin containing two or more allyl groups in one molecule, for example.

[0129] The allyl resin in this embodiment is more preferably represented by the following general formula (8), the following general formula (9), or the following general formula (10).

[0130] [Chemical Formula 14]

[0131]

[0132] [Chemical Formula 15]

[0133]

[0134] [Chemical Formula 16]

[0135]

[0136] In the above general formula (8), R 7 and R 8 Each independently represents an alkyl group, preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 4 carbon atoms, and still more preferably an alkyl group selected from a methyl group and an ethyl group.

[0137] In the general formula (9), n3 is 1 or more and 4 or less, preferably 1 or more and 3 or less, and more preferably 1 or more and 2 or less. In the allyl resin represented by the general formula (9), the ratio of the component where n3 is 1 is preferably 90 mol% or more.

[0138] Specific examples of the allyl resin (A5) in this embodiment include diallylbisphenol A (2,2-bis(3-allyl-4-hydroxyphenyl)propane), the allylphenol resin represented by the general formula (9), and the allylphenol resin represented by the general formula (10). These allyl resins may be used alone or in combination of two or more.

[0139] The thermosetting component (A) of this embodiment may contain thermosetting resins other than components (A1) to (A3), curing accelerators other than component (A4′), and curing resins other than component (A5) within the range not impairing the purpose of the present invention.

[0140] Thermosetting resins other than components (A1) to (A3) may be any thermosetting resin having high heat resistance, and examples thereof include epoxy resins, benzophenones, and benzophenones. Oxazine resin, cyanate resin, and melamine resin, etc. These thermosetting resins can be used alone or in combination of two or more.

[0141] Examples of curing accelerators other than the component (A4') include peroxides, Salts, benzopinacol and its derivatives, and imidazole compounds not having a triazine skeleton (for example, 2-ethyl-4-methylimidazole, etc.) etc. These curing accelerators can be used alone or in combination of two or more.

[0142] Examples of curable resins other than component (A5) include phenolic resins, resins other than component (A5) having C=C double bonds, and resins such as amines, acid anhydrides, and formaldehyde. These curable resins may be used alone or in combination of two or more.

[0143] When using a thermosetting resin other than components (A1) to (A3), a curing accelerator other than component (A4), or a curing resin other than component (A5), the content thereof is preferably 10% by mass or less, more preferably 5% by mass or less, based on the total amount of the solid content of component (A) (i.e., when the amount of the non-volatile components of component (A) excluding the solvent is set to 100% by mass).

[0144] In this embodiment, the content of the thermosetting component (A) in the resin composition is preferably 2% by mass or more, more preferably 5% by mass or more, based on the total amount of solids in the resin composition (i.e., when the total amount of non-volatile components of the resin composition excluding the solvent is set to 100% by mass). In addition, the upper limit of the content of the thermosetting component (A) is preferably 40% by mass or less, more preferably 30% by mass or less.

[0145] By setting the content of the (A) thermosetting component within the above range, the handleability and sheet shape retainability of the resin sheet and the heat resistance of the resin sheet are improved.

[0146] In addition, when the component (A1) of the present embodiment is used, the content of the thermosetting component (A) in the resin composition is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more, based on the total amount of solids in the resin composition (i.e., when the total amount of non-volatile components of the resin composition excluding the solvent is set to 100% by mass). In addition, the upper limit of the content of the thermosetting component (A) is preferably 27% by mass or less, more preferably 25% by mass or less, and even more preferably 23% by mass or less.

[0147] By setting the content of the (A) thermosetting component within the above range, the handleability and sheet shape retainability of the resin sheet and the heat resistance of the resin sheet are improved.

[0148] ((B) Adhesive component)

[0149] In the present embodiment, the resin composition may also include a (B) binder component (hereinafter, also referred to as "(B) component") in addition to the (A) component. The resin composition of the present embodiment can be given film-forming properties by further including the (B) binder component, and the resin composition can be easily formed into a sheet. It should be noted that, when the resin composition of the present embodiment contains the (A1) component that also functions as a binder component, it is also possible not to contain the binder component.

[0150] The binder component (B) in this embodiment is a resin component other than the component (A). The binder component (B) is an oligomer or polymer containing a repeating structure, and preferably has a functional group equivalent of 5000 or greater. When the binder component (B) has functional groups as described above, even if it is considered that the binder component (B) participates in the curing of the resin sheet due to heat, the present invention can distinguish the binder component (B) from the thermosetting component (A).

[0151] The binder component (B) can be selected from a wide range of sources, and is not limited to aliphatic compounds or aromatic compounds. The binder component (B) is preferably at least one resin selected from, for example, a phenoxy resin, an acrylic resin, a methacrylic resin, a polyester resin, a polyurethane resin, and a polyamide-imide resin. From the perspective of heat resistance, a phenoxy resin is more preferred. It should be noted that the polyester resin is preferably a wholly aromatic polyester resin. The binder component (B) can be used alone or in combination of two or more.

[0152] As the phenoxy resin, preferably, a phenoxy resin having one or more skeletons selected from a bisphenol A skeleton (hereinafter, bisphenol A may be referred to as "BisA"), a bisphenol F skeleton (hereinafter, bisphenol F may be referred to as "BisF"), a biphenyl skeleton, and a naphthalene skeleton is preferred, and a phenoxy resin having a bisphenol A skeleton and a bisphenol F skeleton is more preferred.

[0153] From the perspective of easily adjusting the complex viscosity of the resin sheet to a desired range, the weight average molecular weight (Mw) of the binder component (B) is preferably 100 to 1,000,000, more preferably 1,000 to 800,000, and even more preferably 10,000 to 100,000. The weight average molecular weight herein is a standard polystyrene-equivalent value measured by gel permeation chromatography (GPC).

[0154] When the binder component (B) is used in the present embodiment, the content of the binder component (B) in the resin composition is preferably 1% by mass or more, more preferably 2% by mass or more, based on the total amount of the solid content of the resin composition (i.e., when the total amount of the non-volatile components of the resin composition excluding the solvent is set to 100% by mass). In addition, the upper limit of the content of the binder component (B) is preferably 10% by mass or less, more preferably 5% by mass or less.

[0155] By setting the content of the binder component (B) in the resin composition within the above range, it is easy to adjust the complex viscosity of the resin sheet before curing to a desired range, thereby improving the handleability and sheet formability of the resin sheet.

[0156] ((C) Thermally conductive filler)

[0157] In this embodiment, the resin composition preferably contains (C) a thermally conductive filler (hereinafter also referred to as "component (C)") in addition to component (A). Component (C) can improve the thermal and / or mechanical properties of the resin sheet.

[0158] Examples of the thermally conductive filler (C) include boron nitride particles and aluminum oxide particles. Among these, from the perspective of improving the thermal diffusivity of the resin sheet, preferred are (C1) boron nitride particles (hereinafter also referred to as "component (C1)") and (C2) aluminum oxide particles (hereinafter also referred to as "component (C2)").

[0159] The thermally conductive filler (C) may be used alone or in combination of two or more. The thermally conductive filler (C) may also be surface-treated.

[0160] The average particle size of the thermally conductive filler (C) is not particularly limited. The average particle size of the boron nitride particles (C1) is preferably 0.1 μm or greater, more preferably 0.2 μm or greater, and even more preferably 0.3 μm or greater, as measured by d50. The upper limit of the average particle size of the boron nitride particles (C1) is preferably 30 μm or less, more preferably 20 μm or less, and even more preferably 15 μm or less.

[0161] The average particle size of the alumina particles (C2) is preferably 3 μm or larger, more preferably 4 μm or larger, in terms of d50. The upper limit of the average particle size of the alumina particles (C2) is preferably 50 μm or smaller, more preferably 35 μm or smaller, and even more preferably 20 μm or smaller.

[0162] The average particle size of the (C) thermally conductive filler in this specification is a value measured by a dynamic light scattering method.

[0163] The total content of the boron nitride particles (C1) and the aluminum oxide particles (C2) in the resin composition is preferably 50% by mass or greater, more preferably 65% ​​by mass or greater, even more preferably 78.5% by mass or greater, and particularly preferably 80% by mass or greater, based on the total solid content of the resin composition (i.e., when the total non-volatile content of the resin composition excluding the solvent is taken as 100% by mass). By setting the total content of the components (C1) and (C2) in the resin composition to be greater than the above lower limit, the thermal diffusivity of the resin sheet can be improved.

[0164] The upper limit of the total content is preferably 90% by mass or less, more preferably 88% by mass or less, even more preferably 86% by mass or less, and particularly preferably 85% by mass or less. By setting the total content of component (C1) and component (C2) in the resin composition to be below the upper limit, the thermal diffusivity of the resin sheet can be improved.

[0165] When the resin composition contains both (C1) boron nitride particles and (C2) alumina particles, the mass ratio of the (C1) boron nitride particles to the (C2) alumina particles in the resin composition is such that, with the mass of the (C2) alumina particles being 1, the mass of the (C1) boron nitride particles is preferably 0.1 or greater, more preferably 0.2 or greater. By setting the mass ratio to be greater than the above lower limit, the thermal diffusivity of the resin sheet can be improved.

[0166] Furthermore, when the resin composition contains both (C1) boron nitride particles and (C2) aluminum oxide particles, the upper limit of the mass ratio of the (C1) boron nitride particles to the (C2) aluminum oxide particles in the resin composition is preferably 0.75 or less, more preferably 0.6 or less. By setting the mass ratio below the upper limit, the peel strength of the resin sheet after thermal curing can be improved.

[0167] The content of the thermally conductive filler (C) in the resin composition is preferably 50% by mass or greater, more preferably 65% ​​by mass or greater, even more preferably 78.5% by mass or greater, and particularly preferably 80% by mass or greater, based on the total solids content of the resin composition (i.e., when the total non-volatile content of the resin composition excluding the solvent is taken as 100% by mass). By setting the content of the thermally conductive filler (C) in the resin composition to be greater than the above lower limit, the thermal diffusivity of the resin sheet can be improved.

[0168] The upper limit of the content of the thermally conductive filler (C) is preferably 90% by mass or less, more preferably 88% by mass or less, even more preferably 86% by mass or less, and particularly preferably 85% by mass or less. By keeping the content of the thermally conductive filler (C) in the resin composition below the upper limit, the peel strength of the resin sheet after thermal curing can be improved.

[0169] ((D) Coupling agent)

[0170] In the present embodiment, the resin composition preferably further contains a coupling agent (D) in addition to the component (A) and the component (C).

[0171] The coupling agent preferably has a group reactive with the functional group possessed by the thermosetting component (A) described above, and more preferably has a group reactive with the functional group possessed by the thermosetting component (A).

[0172] By using the coupling agent (D), the peel strength between the cured product of the resin sheet and the adherend is improved.

[0173] As (D) coupling agent, from the viewpoint of obtaining the effect of the present invention, preferably silane (silane coupling agent). (D) coupling agent can be used alone or in combination of two or more. In addition, relative to 100 parts by mass of (A) thermosetting component, the amount of the coupling agent as described above is usually 0.1 parts by mass or more, preferably 0.3 parts by mass or more. The upper limit of the content of the coupling agent is usually 7 parts by mass or less, preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

[0174] As an example of the resin composition of the present embodiment, a resin composition containing only (A) a thermosetting component, (C) a thermally conductive filler, and (D) a coupling agent can be mentioned.

[0175] As another example of the resin composition of the present embodiment, as described below, there can be mentioned a resin composition containing (A) a thermosetting component, (C) a thermally conductive filler, (D) a coupling agent, and components other than the above-mentioned components (A), (C), and (D).

[0176] (Other ingredients)

[0177] In this embodiment, the resin composition may further include other components. Examples of such other components include at least one component selected from the group consisting of a crosslinking agent, a pigment, a dye, a defoamer, a leveling agent, a UV absorber, a foaming agent, an antioxidant, a flame retardant, a dispersant, an anti-settling agent, a tackifier, and an ion trap.

[0178] For example, the resin composition may further contain a crosslinking agent in order to adjust the initial adhesiveness and cohesiveness before curing.

[0179] Examples of the crosslinking agent include organic polyisocyanate compounds and organic polyimide compounds. The crosslinking agent may be used alone or in combination of two or more.

[0180] Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, trimers of these polyisocyanate compounds, and isocyanate-terminated urethane prepolymers obtained by reacting these polyisocyanate compounds with a polyol compound.

[0181] Other specific examples of the organic polyisocyanate compound include toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 1,3-xylylenediisocyanate, 1,4-xylylenediisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexylmethane-2,4'-diisocyanate, and lysine isocyanate. The organic polyisocyanate compound may be used alone or in combination of two or more.

[0182] Specific examples of the organic polyimine compound include N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), trimethylolpropane-tris-β-aziridinyl propionate, tetramethylolmethane-tris-β-aziridinyl propionate, and N,N'-toluene-2,4-bis(1-aziridinecarboxamide)triethylenemelamine. The organic polyimine compound may be used alone or in combination of two or more.

[0183] The amount of the crosslinking agent is usually 0.01 parts by mass or more, preferably 0.1 parts by mass or more, relative to 100 parts by mass of the resin component. The upper limit of the amount of the crosslinking agent is usually 12 parts by mass or less, preferably 10 parts by mass or less.

[0184] [Resin sheet]

[0185] The resin sheet of the present embodiment is formed from the resin composition of the present embodiment described above.

[0186] The resin sheet is preferably formed solely from the resin composition of this embodiment from the viewpoint of being able to follow the unevenness of an adherend when used to seal a semiconductor element or sandwiched between a semiconductor element and other electronic components. Specifically, the resin sheet is preferably not a composite material such as a prepreg, which is a combination of a resin composition and a fiber sheet.

[0187] The resin sheet of this embodiment needs to satisfy the condition represented by the following mathematical formula (F1) when observing an area (P1) in a cross section (P) of the resin sheet, wherein the cross section (P) is a cross section cut in a direction perpendicular to the surface of the resin sheet, and the area (P1) is an area surrounded by a square having a side length four times the thickness of the resin sheet and including both surfaces of the resin sheet.

[0188] 0.25≤Ld / Lt≤1···(F1)

[0189] Ld: (C) The vertical length of the thermally conductive filler with the largest cross-sectional diameter (see Figure 1 )

[0190] Lt: The length of the resin sheet in the vertical direction (see Figure 1 )

[0191] If the Ld / Lt value is less than 0.25, thermal conductivity will decrease. On the other hand, if the Ld / Lt value exceeds 1, unevenness will occur on the surface of the resin sheet, adversely affecting adhesion. From the same perspective, the Ld / Lt value is preferably 0.29 or greater, more preferably 0.33 or greater. The upper limit of the Ld / Lt value is preferably 0.99 or less, more preferably 0.95 or less.

[0192] The thermal diffusivity of the resin sheet of this embodiment after thermal curing needs to be 1.0×10 -6 m 2 / s or more, preferably 1.1×10 -6 m 2 / s or more, more preferably 1.2×10 -6 m 2 / s or more, more preferably 1.3×10 -6 m 2 / s or more, more preferably 1.35×10 -6 m 2 / s or more, particularly preferably 1.5×10 -6 m 2 / s or more. In addition, the upper limit of the thermal diffusivity after thermal curing is preferably 1×10 -5 m 2 / s or less, more preferably 8×10 -6 m 2 / s or less, more preferably 5×10 -6 m 2 / s or less, more preferably 4×10 -6 m 2 / s or less, particularly preferably 3×10 -6 m 2 / s or less.

[0193] By setting the thermal diffusivity of the resin sheet after thermal curing within such a range, a cured product having high thermal conductivity can be obtained. The thermal diffusivity of the resin sheet after thermal curing is a characteristic value that can be obtained by the method described in the Examples below.

[0194] The peel strength of the resin sheet of this embodiment after thermal curing is preferably 1.0 N / 10 mm or greater, more preferably 2.0 N / 10 mm or greater, even more preferably 3.0 N / 10 mm or greater, and particularly preferably 4.0 N / 10 mm or greater. Furthermore, the upper limit of the peel strength after thermal curing is more preferably 50 N / 10 mm or less, and even more preferably 40 N / 10 mm or less.

[0195] When the peel strength after thermal curing of the resin sheet of the present embodiment is 1.0 N / 10 mm or more, when the resin sheet is used as a sealing material, high adhesiveness to an adherend can be maintained.

[0196] The peel strength of the resin sheet of the present embodiment after thermal curing can be adjusted to the above range by, for example, adjusting the types (particularly the type of curing accelerator) and the amount of components used in the resin composition.

[0197] The peel strength of the resin sheet after thermal curing of the present embodiment can be determined by performing a peel test between the thermally cured resin sheet and an adherend at a peel angle of 90 degrees using the measurement method described below. Specifically, a test piece was prepared and a peel test was performed as described in the Examples.

[0198] The resin sheet of the present embodiment is formed into a sheet by forming the resin composition, so that application to an adherend becomes easy, and application becomes easy particularly when the adherend has a large area.

[0199] When the resin composition is in sheet form, it is preformed into a shape suitable for the shape after the sealing process, so it can be supplied as a sealing material with a certain degree of uniformity simply by applying it. In addition, when the resin composition is in sheet form, it is excellent in handleability.

[0200] The method for forming the resin composition into a sheet can adopt a conventionally known sheeting method, and is not particularly limited. From the viewpoint of easily obtaining a thin resin sheet, the resin sheet is preferably a coating film of the resin composition. The resin sheet as a coating film of the resin composition can be obtained by a manufacturing method including a step of applying the resin composition.

[0201] Here, as coating method, there is no particular limitation, and known methods can be adopted. In addition, after coating, it can also be dried as required. About drying conditions, there is no particular limitation as long as it is a condition that does not cause the above-mentioned resin combination to solidify. The resin sheet of the present embodiment can be a strip-shaped sheet, or it can be provided in a state of being wound into a roll. The resin sheet of the present embodiment wound into a roll can be continuously sent out from the roll and cut into the desired size etc. and used.

[0202] The thickness of the resin sheet of this embodiment is, for example, preferably 10 μm or greater, more preferably 20 μm or greater, and even more preferably 30 μm or greater. Alternatively, the thickness is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 120 μm or less. Furthermore, when the resin sheet is a coating film of a resin composition, it is easier to make the resin sheet thinner. Therefore, the thickness of the resin sheet of this embodiment is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less.

[0203] (Thermal curing conditions)

[0204] In the thermosetting conditions of the resin sheet of this embodiment, the heating temperature is preferably 50°C or higher, more preferably 100°C or higher, further preferably 130°C or higher, and further preferably 160°C or higher. The upper limit of the heating temperature is preferably 300°C or lower, more preferably 250°C or lower, further preferably 230°C or lower, and further preferably 210°C or lower.

[0205] In the heat curing conditions of the resin sheet of this embodiment, the heating time is preferably 10 minutes or longer, more preferably 20 minutes or longer. The upper limit of the heating time is preferably 10 hours or shorter, more preferably 7 hours or shorter.

[0206] By setting the thermal curing conditions of the resin sheet within the above-mentioned range, thermal curing of the resin sheet can be achieved at a low temperature and in a short time.

[0207] [Laminated body]

[0208] Figure 2 A schematic cross-sectional view of the laminated body 1 according to this embodiment is shown.

[0209] The laminated body 1 of this embodiment includes a first release material 2, a second release material 4, and a resin sheet 3 provided between the first release material 2 and the second release material 4. The resin sheet 3 is the resin sheet of this embodiment.

[0210] The first release material 2 and the second release material 4 preferably have releasability, and there is a difference between the release force of the first release material 2 and the release force of the second release material 4 relative to the resin sheet 3. The materials of the first release material 2 and the second release material 4 are not particularly limited. The ratio of the release force P2 of the second release material 4 to the release force P1 of the first release material 2 (P2 / P1) is preferably 0.02 ≤ P2 / P1 < 1 or 1 < P2 / P1 ≤ 50.

[0211] The first release material 2 and the second release material 4 may be, for example, a release material having release properties itself, a release-treated member, or a member laminated with a release agent. When the first release material 2 and the second release material 4 are not release-treated, examples of the material of the first release material 2 and the second release material 4 include olefin resins, fluororesins, and the like.

[0212] The first release material 2 and the second release material 4 can be made into release materials comprising a release base and a release agent layer formed by coating the release base with a release agent. By making the release materials comprising a release base and a release agent layer, handling becomes easier. Furthermore, the first release material 2 and the second release material 4 can have a release agent layer only on one side of the release base, or they can have release agent layers on both sides of the release base.

[0213] Examples of release substrates include paper substrates, laminated papers obtained by laminating a thermoplastic resin such as polyethylene on the paper substrate, and plastic films. Examples of paper substrates include glassine paper, coated paper, and cast-coated paper. Examples of plastic films include polyester films (e.g., polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate), and polyolefin films (e.g., polypropylene and polyethylene). Among these, polyester films are preferred.

[0214] Examples of the release agent include: silicone-based release agents composed of silicone resins; long-chain alkyl compound-containing release agents composed of compounds containing long-chain alkyl groups, such as polyvinyl carbamate and alkyl urea derivatives; alkyd resin-based release agents composed of alkyd resins (e.g., unmodified alkyd resins and modified alkyd resins); olefin resin-based release agents composed of olefin resins (e.g., polyethylene (e.g., high-density polyethylene, low-density polyethylene, and linear low-density polyethylene), propylene homopolymers having an isotactic structure or syndiotactic structure, and crystalline polypropylene resins such as propylene-α-olefin copolymers); rubber-based release agents composed of rubbers such as natural rubber and synthetic rubbers (e.g., butadiene rubber, isoprene rubber, styrene-butadiene rubber, methyl methacrylate-butadiene rubber, and acrylonitrile-butadiene rubber); and acrylic resin-based release agents composed of acrylic resins such as (meth)acrylate copolymers. These release agents can be used alone or in combination of two or more. Among these release agents, alkyd resin release agents are preferred. In particular, when a phenoxy resin is used as the binder component (B) of the resin composition contained in the resin sheet 3, the use of conventional silicone release agents may cause the release material to be accidentally peeled off before the resin sheet 3 is used. Therefore, alkyd resin release agents are preferably used.

[0215] The thickness of the first release material 2 and the second release material 4 is not particularly limited, but is usually 1 μm or more and 500 μm or less, preferably 3 μm or more and 100 μm or less.

[0216] The thickness of the release agent layer is not particularly limited. When the release agent layer is formed by applying a solution containing a release agent, the thickness of the release agent layer is preferably 0.01 μm to 3 μm, more preferably 0.03 μm to 1 μm.

[0217] The manufacturing method of the laminate 1 is not particularly limited. For example, the laminate 1 can be manufactured through the process described below. First, a resin composition is applied to the first release material 2 to form a coating film. Then, the coating film is dried to form a resin sheet 3. Then, the laminate 1 is obtained by bonding the resin sheet 3 to the second release material 4 at room temperature. It should be noted that in this case, when the types of release materials of the first release material 2 and the second release material 4 are the same, there is a high possibility that the ratio of the release force P2 of the second release material 4 to the release force P1 of the first release material 2 (P2 / P1) reaches P2 / P1<1. Even if the types of release materials of the first release material 2 and the second release material 4 are different, since it is the first release material 2 that is coated with the resin composition, there is a tendency for the value of P2 / P1 to become smaller.

[0218] [Effects of this embodiment]

[0219] According to the resin sheet and the laminate of the present embodiment, the thermal conductivity of the resin sheet having excellent heat resistance after thermal curing can be improved, and the adhesiveness after thermal curing can be improved.

[0220] As described above, the resin sheet of this embodiment can be suitably used for power semiconductor elements. In other words, in the semiconductor device of this embodiment, the semiconductor element is preferably a power semiconductor element. For the power semiconductor element, it is also envisioned that it will work at a high temperature of 200°C or above. Heat resistance is required for the materials used in the semiconductor device having a power semiconductor element. Since the resin sheet of this embodiment has excellent heat resistance, it can be suitably used to cover the power semiconductor element in the semiconductor device, or to be present between the power semiconductor element and other components. In addition, the resin sheet of this embodiment is preferably applicable to multiple semiconductor elements at one time. For example, when the resin composition is in sheet form, it can be used for so-called panel-level packaging, which is to apply a resin sheet to a structure in which semiconductor elements are arranged in each gap of a frame having multiple gaps, and to seal the frame and the semiconductor element at one time.

[0221] Furthermore, the sealing of semiconductor components can also be used as a cover to protect the back surface of flip-chip components. Conventional protective sheets block heat generated by the components, trapping it within the components. However, using the resin sheet of this embodiment as a back surface protective sheet for flip-chip components effectively dissipates heat generated by the components.

[0222] Furthermore, the resin sheet of this embodiment exhibits excellent thermal conductivity after thermal curing, and thus can effectively transfer heat generated by power semiconductor elements to a heat sink, etc. Specifically, due to its excellent heat resistance and thermal conductivity, the resin sheet of this embodiment can be used to seal power semiconductor elements designed to operate at high temperatures exceeding 200°C, or to be positioned between power semiconductor elements and other electronic components, thereby excelling in transferring heat generated by the power semiconductor elements to a heat sink, etc.

[0223] As described above, the resin sheet of this embodiment can be suitably used for semiconductor elements using compound semiconductors. In other words, in the semiconductor device of this embodiment, the semiconductor element is preferably a semiconductor element using a compound semiconductor. Since the semiconductor element using compound semiconductors has different characteristics from silicon semiconductor elements, it can be preferably used for applications such as power semiconductor elements, high-output power devices for base stations, sensors, detectors, and Schottky barrier diodes. In these applications, the heat resistance of semiconductor elements using compound semiconductors is also taken into consideration. Since the resin sheet of this embodiment has excellent heat resistance, it can be suitably used in combination with semiconductor elements using compound semiconductors. In addition, since the resin sheet of this embodiment has excellent thermal conductivity after thermal curing, it can effectively transfer the heat generated by the semiconductor element using compound semiconductors to a heat sink, etc.

[0224] The resin sheet of this embodiment is preferably used to seal a semiconductor element using a compound semiconductor. Alternatively, the resin sheet of this embodiment is preferably used between a semiconductor element using a compound semiconductor and other electronic components. Examples of other electronic components include printed circuit boards and lead frames.

[0225] The upper limit of the operating temperature of silicon semiconductor devices is approximately 175°C. Therefore, power semiconductor devices preferably use semiconductor devices using compound semiconductors capable of high-temperature operation. Examples of compound semiconductors include silicon carbide, gallium nitride, aluminum gallium nitride, gallium oxide, and gallium arsenide. Silicon carbide, gallium nitride, aluminum gallium nitride, and gallium oxide are preferred.

[0226] The resin sheet of this embodiment has excellent heat resistance and thermal conductivity, and therefore can be used to seal semiconductor elements using compound semiconductors that are intended to operate at high temperatures above 200°C, or to be present between semiconductor elements using compound semiconductors and other electronic components, and has an excellent ability to transfer the heat generated by these semiconductor elements to a heat sink, etc.

[0227] [Variations of the Embodiments]

[0228] The present invention is not limited to the above-described embodiment, and modifications and improvements within the scope that can achieve the object of the present invention are included in the present invention.

[0229] In the above embodiment, a laminate including a first release material, a second release material, and a resin sheet provided between the first and second release materials has been described. However, a laminate including a release material only on one side of a resin sheet may also be used.

[0230] In addition, in the above-mentioned embodiment of the semiconductor device, the semiconductor sealing application is described, but in addition to this, the resin sheet of the present invention can also be used as an insulating material for circuit substrates (for example, hard printed circuit board materials, materials for flexible circuit boards, and interlayer insulating materials for laminated substrates, etc.), adhesive films for laminates, and adhesives, etc.

[0231] Example

[0232] Hereinafter, the present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[0233] [Examples and Comparative Examples]

[0234] [Preparation of resin composition]

[0235] The resin compositions of Examples 1 to 4 were prepared according to the mixing ratios (mass % (ratios calculated as solid content)) shown in Table 1.

[0236] The materials used in the preparation of the resin composition are as follows.

[0237] (Thermosetting component)

[0238] First maleimide resin: long-chain alkyl maleimide resin (solid at 25°C, maleimide resin represented by the above general formula (A1-1-1), "SLK-3000" manufactured by Shin-Etsu Chemical Co., Ltd.)

[0239] Second maleimide resin: a maleimide resin having a biphenyl group (maleimide resin represented by the above general formula (3), "MIR-3000" manufactured by Nippon Kayaku Co., Ltd.)

[0240] Third maleimide resin: long-chain alkyl maleimide resin (liquid at 25°C, maleimide resin represented by the general formula (7-1-1), "SLK-1500" manufactured by Shin-Etsu Chemical Co., Ltd.)

[0241] Allyl resin: diallyl bisphenol A ("DABPA" manufactured by Yamato Chemical Industry Co., Ltd.)

[0242] Compound having a triazine skeleton: 2,4-diamino-6-[2-(2-ethyl-4-methyl-1-imidazolyl)ethyl]-1,3,5-triazine ("2E4MZ-A" manufactured by Shikoku Chemicals Co., Ltd.)

[0243] (Coupling agent)

[0244] Coupling agent: 3-glycidoxypropyltriethoxysilane

[0245] (Thermal conductive filler)

[0246] Alumina particles-1: (“CB-A50S” manufactured by Showa Denko K.K., average particle size (d50): 50 μm)

[0247] Alumina particles-2: (“CB-A30S” manufactured by Showa Denko K.K., average particle size (d50): 30 μm)

[0248] Alumina particles-3: (“CB-P05” manufactured by Showa Denko K.K., average particle size (d50): 4 μm)

[0249] Boron nitride particles-1: (Showa Denko K.K. "UHP-2", average particle size (d50): 11 μm)

[0250] Boron nitride particles-2: (Showa Denko K.K. "UHP-S2", average particle size (d50): 0.7 μm)

[0251] <Evaluation of Resin Sheet Before Thermal Curing>

[0252] [Production of Laminated Body Including Resin Sheet]

[0253] A resin varnish (a coating solution prepared by dissolving a resin composition in cyclohexanone, with a solids concentration of 72% by mass) was applied to a first release material (a polyethylene terephthalate film provided with a release layer formed from an alkyd resin release agent, 38 μm thick) using a knife coater and dried at 90°C for 1 minute and then at 115°C for 1 minute. The thickness of the dried resin composition is shown in Table 1. Immediately after removal from the drying oven, the dried resin composition was laminated with a second release material (a polyethylene terephthalate film provided with a release layer formed from a silicone release agent, 38 μm thick) at room temperature to produce a laminated body comprising the first release material, a resin sheet formed from the resin composition, and the second release material laminated in this order.

[0254] <Evaluation of Resin Sheet After Thermal Curing>

[0255] [Production of Laminated Body Including Resin Sheet]

[0256] A laminate was obtained in the same manner as in the evaluation of the resin composition before thermal curing described above.

[0257] [Thickness of resin sheet]

[0258] The measurement was performed using a constant pressure thickness gauge manufactured by TECLOCK Co., Ltd. (Model: "PG-02J", standard specifications: in accordance with JIS K6783, Z1702, and Z1709).

[0259] [Cross-sectional observation of resin sheet]

[0260] One side of the resin sheet in the obtained laminate was laminated to a glass plate by performing reduced pressure pressing at a lamination temperature of 130°C (laminating device: Nikko Materials Co., Ltd. "V-130"; conditions: reaching pressure 100Pa, applying pressure 0.3MPa, time 30 seconds), and the resin sheet was cured under a heat curing condition of 4 hours at a temperature of 200°C. Then, the glass plate was laminated to the other side of the resin sheet using a two-component curing epoxy resin adhesive (Konishi Co., Ltd., product name "QUICK 5"). It should be noted that the second peeling material and the first peeling material of the resin sheet in the laminate were peeled off before being attached to the glass plate. Then, a sample was made. For this sample, a scanning electron microscope (manufactured by ZEISS, product name "CrossBeam 550") was used to observe the area (P1) of the cross section (P) cut in a direction perpendicular to the surface of the resin sheet. The area (P1) is an area surrounded by a square with a side length of 4 times the thickness of the resin sheet and including two surfaces of the resin sheet. Furthermore, the values ​​of Ld and Lt described below were measured, and the value of Ld / Lt was calculated. The results are shown in Table 1. In addition, a SEM photograph of the cross section of the resin sheet obtained in Example 4 is shown as follows. Figure 3 shown.

[0261] Ld: (C) The vertical length of the thermally conductive filler with the largest cross-sectional diameter.

[0262] Lt: Length of the resin sheet in the vertical direction

[0263] [Measurement of Thermal Diffusivity of Resin Sheet after Thermal Curing]

[0264] Resin sheets were laminated to a thickness of 200 μm and cured at 200°C for 4 hours to produce a sample. The first and second release materials of the laminate were removed as needed during the lamination process. The thermal diffusivity of this sample was measured using a thermal diffusivity measuring instrument ("ai-Phase Mobile 1" manufactured by Iphase Co., Ltd.) using the temperature wave method.

[0265] The results are shown in Table 1.

[0266] [Determination of peel strength]

[0267] One side of the resin sheet in the obtained laminate was laminated at a lamination temperature of 130°C by performing decompression lamination (laminating device: Nikko Materials Co., Ltd. "V-130"; conditions: arrival pressure 100Pa, applied pressure 0.3MPa, time 30 seconds) on a copper plate (JIS-C1220P specification, thickness 400μm), and then a copper foil (size 50mm×10mm, thickness 150μm, JIS H 3100 specification) was laminated to the other side of the resin sheet by performing decompression lamination under the same conditions as above. It should be noted that the second peeling material and the first peeling material of the resin sheet in the laminate were peeled off before being pasted on the Si wafer and the copper plate, respectively. Then, the resin sheet was cured under a thermal curing condition of 4 hours at a temperature of 200°C to prepare a sample. The copper foil was peeled from the cured resin sheet using a tensile testing machine ("Autograph AG-IS" manufactured by Shimadzu Corporation) at a peel rate of 50 mm / min and a peel angle of 90 degrees. The peel strength (unit: N / 10 mm) between the copper foil and the cured resin sheet was measured. The measurement was performed at 25°C and a relative humidity of 50%. The results are shown in Table 1.

[0268]

[0269] As is clear from the results shown in Table 1, the resin sheets obtained in Examples 1 to 4 had a Ld / Lt value within the range of 0.25 to 1, had high peel strength, and had high thermal diffusivity after thermal curing.

Claims

1. A resin sheet formed from a resin composition containing (A) a thermosetting component and (C) a thermally conductive filler, wherein: The (A) thermosetting component contains (A1) a first maleimide resin, (A2) a second maleimide resin, and (A3) a third maleimide resin. The first maleimide resin (A1) is a maleimide resin that is solid at 25° C. and has two or more maleimide groups in one molecule, wherein the bonding group connecting at least one pair of two maleimide groups has four or more methylene groups in the main chain. The first maleimide resin (A1) is represented by the following general formula (A1): The second maleimide resin (A2) is represented by the following general formula (1) or the following general formula (4), The third maleimide resin (A3) is a maleimide resin that is liquid at 25° C. and has two or more maleimide groups in one molecule, and the bonding group connecting at least one pair of two maleimide groups has four or more methylene groups as the main chain. The third maleimide resin (A3) is represented by the following general formula (7): In the above general formula (A1), n 11 is an integer greater than 0, n 11 The average value of is greater than 0.5 and less than 5, L 11 and L 12 Each independently represents a substituted or unsubstituted alkylene group having 4 or more carbon atoms, wherein at least one -CH2- in the alkylene group is optionally replaced by -CH2-O- or -O-CH2-, and when the hydrogen of the alkylene group is substituted, the substituent is an alkyl group having 1 or more and 14 or less carbon atoms, or an alkoxy group having 1 or more and 14 or less carbon atoms, and these substituents are optionally bonded to each other to form an alicyclic structure or a heterocyclic structure, X 11 are each independently a divalent group having a phthalimide group, In the general formula (1), k is an integer greater than or equal to 1, the average value of k is greater than or equal to 1 and less than or equal to 10, m1 and m2 are each independently an integer greater than or equal to 1 and less than or equal to 2, wherein the sum of m1 and m2 is less than or equal to 3, n1 and n2 are each independently an integer greater than or equal to 0 and less than or equal to 4, and R 1 and R 2 Each independently represents an alkyl group having 1 to 6 carbon atoms, and the plurality of R 1 Same or different, multiple R 2 Same or different from each other, In the above general formula (4), R 3 ~R 6 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, L 1 is an alkylene group having 1 to 3 carbon atoms, L 2 and L 3 are each independently an alkylene group having 1 to 2 carbon atoms or an arylene group having 6 to 10 carbon atoms, p and q are each independently 0 or 1, wherein L 1 , L 2 and L 3 The total number of carbon atoms of the alkylene group in is 3 or less, In the above general formula (7), n is an integer greater than or equal to 0, and the average value of n is greater than or equal to 0.5 and less than or equal to 5. L 4 and L 5 Each independently represents a substituted or unsubstituted alkylene group having 4 or more carbon atoms, in which at least one -CH2- is optionally replaced by -CH2-O- or -O-CH2-, and when the hydrogen of the alkylene group is substituted, the substituent is an alkyl group having 1 or more and 10 or less carbon atoms, or an alkoxy group having 1 or more and 10 or less carbon atoms, and these substituents are optionally bonded to each other to form an alicyclic structure, X is each independently a divalent group having a phthalimide group, The thermal diffusivity of the resin sheet after thermal curing is 1.0×10 -6 m 2 / s or more, When observing a region (P1) in a cross section (P) of the resin sheet, the condition represented by the following mathematical formula (F1) is satisfied. The cross section (P) is a cross section cut in a direction perpendicular to the surface of the resin sheet. The region (P1) is a region enclosed by a square having a side length four times the thickness of the resin sheet and including both surfaces of the resin sheet. 0.25≤Ld / Lt≤1···(F1) Ld: the length of the thermally conductive filler (C) having the largest cross-sectional diameter in the vertical direction; Lt: The length of the resin sheet in the vertical direction.

2. The resin sheet according to claim 1, wherein The (A) thermosetting component further contains (A4) a compound having a triazine skeleton.

3. The resin sheet according to claim 2, wherein The (A4) compound having a triazine skeleton is an imidazole compound having a triazine skeleton. The resin sheet according to claim 1 , wherein The (A) thermosetting component further contains (A5) an allyl resin. The resin sheet according to claim 1 , wherein The resin composition further contains (C1) boron nitride particles. The resin sheet according to claim 5 , wherein The resin composition further contains (C2) aluminum oxide particles.

7. The resin sheet according to claim 6, wherein The total content of the (C1) boron nitride particles and the (C2) aluminum oxide particles is 78.5% by mass or more based on the total solid content of the resin composition. 8 . The resin sheet according to claim 1 , which is used for sealing a semiconductor element or for being interposed between the semiconductor element and other electronic components. 9 . The resin sheet according to claim 1 , which is used to be between a radiator and an electronic component. 10 . The resin sheet according to claim 1 , which is used for sealing a semiconductor element using a compound semiconductor, or is used between a semiconductor element using the compound semiconductor and other electronic components.

11. The resin sheet according to any one of claims 1 to 7, wherein The resin sheet is a coating film of the resin composition.

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