JP2024075810A - Resin Sheet - Google Patents

Abstract

[Problem] To provide a resin sheet capable of improving embeddability. [Solution] A resin sheet formed from a resin composition containing a resin component (A), the resin component (A) contains a first maleimide resin (A1), the first maleimide resin (A1) has two or more maleimide groups in one molecule, and a bonding group connecting at least one pair of two maleimide groups is a maleimide resin having four or more methylene groups in the main chain, and the content of the first maleimide resin (A1) is 30% by mass or more and 58% by mass or less when the total amount of the resin component (A) in the resin composition is taken as 100% by mass. [Selected Figure] Figure 1

Description

The present invention relates to a resin sheet.

The incorporation of inorganic fillers such as silica into resin sheets used in semiconductors has been considered. Patent Document 1 discloses an adhesive film in which a support such as polyethylene terephthalate, a resin composition layer formed on the support, and a protective film such as a polypropylene film that protects the resin composition layer are laminated in this order. The resin composition described in Patent Document 1 contains a multifunctional epoxy resin, a curing agent, a phenoxy resin, and an inorganic filler.

JP 2010-168470 A

However, when applied to power semiconductor elements that are expected to operate at high temperatures of 200°C or higher, the resin composition described in Patent Document 1 does not have sufficient heat resistance. Therefore, in order to improve heat resistance, the use of maleimide resin as a thermosetting component has been considered. However, it has been found that when a thermosetting resin composition using maleimide resin is used, the embedding ability when sealing semiconductor elements may be insufficient.

The present invention aims to provide a resin sheet that can improve embeddability.

According to one aspect of the present invention, there is provided a resin sheet formed from a resin composition containing a resin component (A), the resin component (A) containing a first maleimide resin (A1), the first maleimide resin (A1) having two or more maleimide groups in one molecule, a bonding group connecting at least one pair of two maleimide groups being a maleimide resin having four or more methylene groups in the main chain, and the content of the first maleimide resin (A1) when the total amount of the resin component (A) of the resin composition is taken as 100% by mass is 30% by mass or more and 58% by mass or less.

In the resin sheet according to one embodiment of the present invention, it is preferable that the resin component (A) further contains a second maleimide resin (A2), and the second maleimide resin (A2) is a maleimide resin having a different chemical structure from the first maleimide resin (A1).

In the resin sheet according to one embodiment of the present invention, the second maleimide resin (A2) is preferably a maleimide resin containing two or more maleimide groups and two or more phenylene groups in one molecule.

In the resin sheet according to one embodiment of the present invention, it is preferable that the resin composition further contains (B) a compound having an adhesion imparting agent.

In the resin sheet according to one embodiment of the present invention, it is preferable that the adhesion promoter (B) contains a compound having a triazine skeleton (B1).

In the resin sheet according to one embodiment of the present invention, it is preferable that the adhesion promoter (B) is a compound (B1) having a basic group and a triazine skeleton in one molecule.

In the resin sheet according to one embodiment of the present invention, it is preferable that the adhesion promoter (B) is a compound having a triazine skeleton and an imidazole structure in one molecule.

In the resin sheet according to one embodiment of the present invention, it is preferable that the adhesion imparting agent (B) contains a coupling agent (B2).

In the resin sheet according to one embodiment of the present invention, it is preferable that the (A) resin component further contains (A3) an allyl resin.

In one embodiment of the resin sheet of the present invention, the resin sheet is preferably used to fill gaps.

In one aspect of the resin sheet of the present invention, the resin sheet is preferably used to encapsulate a semiconductor element or to be interposed between a semiconductor element and another electronic component.

In one aspect of the present invention, the resin sheet is preferably used to encapsulate multiple semiconductor chips at once.

According to one aspect of the present invention, a resin sheet that can improve embeddability can be provided.

1 is a schematic cross-sectional view of a laminate according to an embodiment of the present invention. 1A to 1C are diagrams for explaining a method for producing a package component that is a test piece for embeddability. 3A and 3B are diagrams showing a packaged component that is an embeddable test piece, in which FIG. 3A is a top view and FIG. 3B is a cross-sectional view.

[Resin composition]
First, a resin composition for forming the resin sheet according to the present embodiment will be described.
The resin composition according to the present embodiment contains a resin component (A). The resin component (A) according to the present embodiment contains a first maleimide resin (A1).

((A) Resin Component)
The resin component (A) (hereinafter may be simply referred to as "(A)") has a property of controlling the physical properties of the resin composition such as the elastic modulus, the glass transition point, etc. As described above, the resin component (A) in this embodiment contains the first maleimide resin (A1) (hereinafter may be simply referred to as "(A1)").

(A1) First Maleimide Resin The (A1) first maleimide resin in this embodiment is a maleimide resin having two or more maleimide groups in one molecule, and a bonding group connecting at least one pair of two maleimide groups having four or more methylene groups in the main chain.
From the viewpoint of flexibility of the cured product, the linking group linking the two maleimide groups preferably has six or more methylene groups in the main chain, more preferably has eight or more methylene groups in the main chain, and particularly preferably has ten or more methylene groups in the main chain. Moreover, it is more preferable that these methylene groups are linked to form an alkylene group having four or more carbon atoms. In this alkylene group, at least one -CH ₂ - may be replaced by -CH ₂ -O- or -O-CH ₂ -.
In addition, the linking group connecting the two maleimide groups preferably has one or more side chains from the viewpoint of flexibility of the cured product. Examples of the side chain include an alkyl group and an alkoxy group. Furthermore, when there are two or more side chains, the side chains may be bonded to each other to form an alicyclic structure.

By using (A1), the heat resistance of the resin sheet can be improved while also improving embeddability. In addition, (A1) is highly compatible with other maleimide resins.

In this embodiment, the first maleimide resin (A1) is preferably represented by the following general formula (1) from the viewpoint of the flexibility and heat resistance of the cured product.

In the general formula (1), ⁿ¹ is an integer of 0 or more, preferably an integer of 1 to 10, and more preferably an integer of 1 to 5. The average value of ⁿ¹ is preferably 0.5 to 5, and more preferably 1 to 2.
^L1 and ^L2 are each independently a substituted or unsubstituted alkylene group having 4 or more carbon atoms, in which at least one _-CH2- may be replaced with _-CH2 -O- or -O- _CH2- . From the viewpoint of flexibility of the cured product, the number of carbon atoms in this alkylene group is preferably 6 or more, more preferably 8 or more, and particularly preferably 10 to 30. In addition, when hydrogen of the alkylene group is substituted, the substituent is an alkyl group having 1 to 14 carbon atoms, or an alkoxy group having 1 to 14 carbon atoms. Furthermore, these substituents may be bonded to each other to form an alicyclic structure or a heterocyclic structure.
Each ^X1 is independently a group that does not have a substituted or unsubstituted alkylene group having 4 or more carbon atoms (including those in which at least one -CH ₂ - is replaced with -CH ₂ -O- or -O-CH ₂ -), and is preferably a divalent group having a phthalimide group. The phthalimide group also includes groups derived from phthalimide. Specific examples of ^X1 include groups represented by the following structural formula (2), the following general formula (3), or the following general formula (4).

In the general formula (3), R ¹ and R ² each independently represent a hydrogen atom, a methyl group, or an ethyl group, and are preferably a methyl group.
Specific examples of the maleimide resin represented by general formula (1) in the present embodiment include compounds represented by the following general formula (5), the following general formula (6), or the following general formula (7).

In the general formula (5), ⁿ² is an integer of 1 or more and 5 or less.
In the general formula (6), ⁿ³ is an integer of 1 to 5. The average value of n is 1 to 2.
In the general formula (7), ⁿ⁴ is an integer of 1 to 5. The average value of n is 1 to 2.
An example of a maleimide resin product represented by the general formula (5) is "BMI-3000" manufactured by Designer Molecules Inc.
An example of a maleimide resin product represented by the general formula (6) is "BMI-1700" manufactured by Designer Molecules Inc.
An example of a maleimide resin product represented by the general formula (7) is "BMI-1500" manufactured by Designer Molecules Inc.

In this embodiment, the content of the first maleimide resin (A1) is required to be 30% by mass or more and 58% by mass or less when the total amount of the resin components (A) in the resin composition is taken as 100% by mass. If the content of (A1) is within the above range, the heat resistance of the resin sheet can be improved while the embeddability can be improved. From the same viewpoint, the lower limit of the content of (A1) is preferably 33% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more, and the upper limit of the content of (A1) is preferably 56% by mass or less.

(A2) Second Maleimide Resin In the present embodiment, the resin component (A) contained in the resin composition may further contain a second maleimide resin having a different chemical structure from the first maleimide resin (A1) as (A2) from the viewpoint of increasing the storage modulus E' at 250 ° C. of the cured resin sheet. The second maleimide resin (A2) in the present embodiment (hereinafter may be simply referred to as "(A2)") is not particularly limited as long as it is a maleimide resin having a different chemical structure from the first maleimide resin (A1) and containing two or more maleimide groups in one molecule. That is, the second maleimide resin (A2) is a maleimide resin having two or more maleimide groups in one molecule, and the bonding group connecting any two maleimide groups does not have four or more methylene groups in the main chain. When the resin sheet contains (A2), the cohesiveness of the resin sheet after curing is improved. Therefore, it is possible to prevent a decrease in adhesion caused by cohesive failure of the resin sheet after curing.

From the viewpoint of heat resistance, the second maleimide resin (A2) in this embodiment preferably contains, for example, a benzene ring, and more preferably contains a structure in which a maleimide group is linked to a benzene ring. In addition, it is preferable that the maleimide compound has two or more structures in which a maleimide group is linked to a benzene ring.

In this embodiment, the second maleimide resin (A2) preferably contains two or more maleimide groups and two or more phenylene groups in one molecule, and is preferably a maleimide resin containing two or more maleimide groups and one or more biphenyl skeletons in one molecule (hereinafter, sometimes simply referred to as "biphenylmaleimide resin").

In the present embodiment, the second maleimide resin (A2) is preferably represented by the following general formula (8) from the viewpoint of heat resistance and adhesiveness.

In the general formula (8), ⁿ⁵ and ⁿ⁶ each independently represent an integer of 1 to 2, and are more preferably 1. However, the sum of ⁿ⁵ and ⁿ⁶ is 3 or less.
^R3 and ^R4 are each independently an alkyl group having 1 to 6 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. Multiple ^R3s are the same or different from each other. Multiple ^R4s are the same or different from each other.
ⁿ⁷ and ⁿ⁸ each independently represent an integer of 0 or more and 4 or less, preferably an integer of 0 or more and 2 or less, and more preferably 0.
n ⁹ is an integer of 1 or more, and the average value of n ⁹ is preferably 1 or more and 10 or less, more preferably 1 or more and 5 or less, and even more preferably 1 or more and 3 or less.

In this embodiment, the maleimide resin represented by the general formula (8) is, for example, a compound represented by the following general formula (9).

In the general formula (9), ⁿ⁹ is the same as ⁿ⁹ in the general formula (8).
An example of the maleimide resin represented by the general formula (9) is "MIR-3000" manufactured by Nippon Kayaku Co., Ltd.

In addition, the second maleimide resin (A2) in this embodiment is also preferably a maleimide resin containing two or more maleimide groups and two or more phenylene groups in one molecule. From the viewpoint of increasing solubility in a solvent and improving sheet formability, it is preferable that the phenylene group has a substituent. Examples of the substituent include alkyl groups such as methyl groups and ethyl groups, and alkylene groups.
From the viewpoint of sheet formability, the second maleimide resin (A2) in the present embodiment is preferably a maleimide resin having an ether bond between the maleimide group and the phenylene group.

The maleimide resin containing two or more maleimide groups and two or more phenylene groups in one molecule is represented, for example, by the following general formula (10).

In the general formula (10), ^R5 , ^R6 , ^R7 , and ^R8 are each independently a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, ^L3 is an alkylene group having 1 to 3 carbon atoms, ^L4 and ^L5 are each independently an alkylene group having 1 to 2 carbon atoms or an arylene group having 6 to 10 carbon atoms, and ⁿ¹⁰ and ⁿ¹¹ are each independently 0 or 1. However, the total number of carbon atoms of the alkylene groups among ^L3 , ^L4 , and ^L5 is 3 or less.

In this embodiment, the content of the maleimide resin in (A) (the sum of (A1) and (A2)) 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 solids in (A) (i.e., when the amount of non-volatile content of (A) excluding the solvent is taken as 100% by mass). The upper limit of the content of the maleimide resin in (A) is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 92.5% by mass or less, based on the total amount of solids in (A). By having the content of the maleimide resin in (A) in such a range, the heat resistance after curing of the resin sheet according to this embodiment can be further improved.

(A3) Allyl Resin The (A) resin component contained in the resin composition in this embodiment preferably further contains (A3) allyl resin. The (A3) allyl resin (hereinafter sometimes simply referred to as "(A3)") is preferably liquid at room temperature. By including the (A) resin component allyl resin, it becomes easier to lower the reaction temperature of the resin sheet according to this embodiment and improve the peel strength of the resin sheet after curing.

In the present embodiment, the mass ratio of the total amount of maleimide resins (A1+A2) to the allyl resin (A3) (total amount of maleimide resins (A1+A2)/(A3)) is preferably 1.5 or more, more preferably 3 or more, and particularly preferably 5 or more.
In addition, if the mass ratio (total amount of maleimide resin (A1+A2)/(A3)) is within the above range, the complex viscosity η of the resin sheet is appropriately adjusted, and the flowability of the resin sheet when applied to an adherend is ensured, while further improving the heat resistance of the resin sheet after curing. Furthermore, if the mass ratio (total amount of maleimide resin (A1+A2)/(A3)) is within the above range, the bleed-out of the allyl resin from the resin sheet is also suppressed. The upper limit of the mass ratio (total amount of maleimide resin (A1+A2)/(A3)) is not particularly limited. For example, the mass ratio (total amount of maleimide resin (A1+A2)/(A3)) may be 50 or less, preferably 25 or less, more preferably 15 or less, and particularly preferably 10 or less.

The allyl resin (A3) in the present embodiment is not particularly limited as long as it is a resin having an allyl group. The allyl resin (A3) in the present embodiment is preferably, for example, an allyl resin containing two or more allyl groups in one molecule.
The allyl resin (A3) preferably has an aromatic ring. The allyl group in the allyl resin (A3) is preferably directly bonded to the aromatic ring. The allyl resin (A3) preferably has a hydroxyl group, and the hydroxyl group is preferably directly bonded to the aromatic ring.
The allyl resin in the present embodiment is represented by the following general formula (11).

In the general formula (11), R ⁹ and R ¹⁰ each independently represent 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 further preferably an alkyl group selected from the group consisting of a methyl group and an ethyl group.
In the general formula (11), ⁿ¹² 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 (14), the ratio of components in which ⁿ¹² is 1 is preferably 90 mol % or more.

In the present embodiment, the allyl resin (A3) is preferably an allylphenol resin represented by the general formula (11). Among the compounds represented by the general formula (11), it is preferable to have a 4-hydroxyphenyl group having a hydroxy group at the 4th position of the phenyl group. Among the compounds represented by the general formula (11), it is preferable to have an allyl group at the 3rd or 5th position of the phenyl group. Among the compounds represented by the general formula (11), it is preferable to have a hydroxy group at the ortho position of the allyl group. Furthermore, among the compounds represented by the general formula (11), diallyl bisphenol A (2,2-bis(3-allyl-4-hydroxyphenyl)propane) is particularly preferable. These allyl resins can be used alone or in combination of two or more.

By using the aforementioned (A1), (A2), and (A3) as the (A) resin component, it is possible to obtain a resin cured product that undergoes a three-dimensional network formation upon heating and has the desired physical properties.

(A4) Other Resin Component The (A) resin component of the present embodiment may contain (A4) other resin component (hereinafter, may be simply referred to as “(A4)”) in addition to (A1), (A2), and (A3), as long as the object of the present invention is not impaired.
Examples of the other resin components (A4) include thermosetting resins, thermoplastic resins, or crosslinking agents other than (A1), (A2), and (A3).
By using (A4) other resin components, it is possible to improve the peel strength of the resin sheet after curing, to bond with (A1), (A2), (A3) or other components, to improve the heat resistance of the resin sheet, and to improve the handleability and sheet formability of the resin sheet.

Examples of the thermosetting resin include phenolic resin, epoxy resin, benzoxazine resin, cyanate resin, and melamine resin. These thermosetting resins can be used alone or in combination of two or more. By using a thermosetting resin as (A4), the peel strength of the resin sheet after curing can be further improved and the heat resistance can be improved. However, from the viewpoint of high heat resistance, it is preferable that the (A) resin component does not substantially contain an epoxy resin.

The thermoplastic resin can be selected from a wide range of compounds, whether aliphatic or aromatic, for the purpose of making it easier to adjust the complex viscosity of the resin sheet before curing to a desired range and improving the handling and sheet formability of the resin sheet. The thermoplastic resin is preferably at least one resin selected from the group consisting of, for example, phenoxy resin, acrylic resin, methacrylic resin, polyester resin, urethane resin, and polyamideimide resin, and more preferably at least one resin selected from the group consisting of phenoxy resin and polyamideimide resin from the viewpoint of heat resistance. The polyester resin is preferably a wholly aromatic polyester resin. In addition, as the polyamideimide resin, a rubber-modified polyamideimide resin is preferable from the viewpoint of improving the flexibility of the resin sheet. The thermoplastic resin can be used alone or in combination of two or more types.

The phenoxy resin is preferably a phenoxy resin having one or more skeletons selected from the group consisting of 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, and more preferably a phenoxy resin having a bisphenol A skeleton and a bisphenol F skeleton.

From the viewpoint of making it easier to adjust the complex viscosity of the resin sheet to the desired range, the weight average molecular weight (Mw) of the thermoplastic resin is preferably 10,000 or more and 1,000,000 or less, more preferably 15,000 or more and 800,000 or less, and even more preferably 20,000 or more and 500,000 or less. In this specification, the weight average molecular weight is a standard polystyrene equivalent value measured by gel permeation chromatography (GPC) method.

In this embodiment, when a thermoplastic resin is used as (A4), its content is preferably 1.5% by mass or more, more preferably 2% by mass or more, based on the total amount of solids in the resin composition (i.e., when the total amount of non-volatiles in the resin composition excluding the solvent is taken as 100% by mass). The upper limit of the content of the resin composition is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 15% by mass or less. By setting the content of the thermoplastic resin within the above range, film-forming properties can be imparted, and the resin composition can be easily formed into a sheet.
The thermoplastic resin may have a functional group in order to have a function of bonding (A1), (A2), (A3), or other components. When the thermoplastic resin has a functional group in this way, it can have thermosetting properties in addition to thermoplastic properties.

Examples of the crosslinking agent include organic polyisocyanate compounds. The crosslinking agent can be used alone or in combination of two or more. By using the crosslinking agent, it is possible to bond with (A1), (A2), (A3) or other components to improve the handleability, sheet formability, and heat resistance of the resin sheet, and to adjust the initial adhesion and cohesion of the resin sheet before curing.

Examples of the organic polyisocyanate compound include aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, alicyclic polyisocyanate compounds, and trimers of these polyisocyanate compounds, as well as isocyanate-terminated ethane prepolymers obtained by reacting these polyisocyanate compounds with polyol compounds.
More specific examples of the organic polyisocyanate compound include, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 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 can be used alone or in combination of two or more.

When using such a crosslinking agent, the content of the crosslinking agent is preferably 0.01 parts by mass or more, and more preferably 0.1 parts by mass or more, per 100 parts by mass of the total amount of (A1), (A2), and (A3) described above. The upper limit of the content of the crosslinking agent is preferably 12 parts by mass or less, and more preferably 10 parts by mass or less.

In this embodiment, the content of the resin component (A) in the resin composition is preferably 2% by mass or more, more preferably 5% by mass or more, and particularly preferably 10% by mass or more, based on the total amount of solids in the resin composition (i.e., when the total amount of non-volatile content of the resin composition excluding the solvent is taken as 100% by mass). The upper limit of the content of the resin component (A) is preferably 75% by mass or less, more preferably 60% by mass or less, and particularly preferably 40% by mass or less.
When the content of the (A) resin component is within the above range, the handleability of the resin sheet, the sheet shape retention, and the heat resistance of the resin composition are improved.

In the present embodiment, it is preferable that the resin composition further contains an adhesion imparting agent (B) (hereinafter, sometimes simply referred to as "(B)"). The adhesion imparting agent (B) can further improve the peel strength of the resin composition after curing.
Examples of the adhesion promoter (B) include a compound having a triazine skeleton (B1) and a coupling agent (B2).

(B1) Compound Having a Triazine Skeleton The compound having a triazine skeleton (B1) (hereinafter, may be simply referred to as "(B1)") is preferably a compound as follows: That is, (B1) is preferably a compound having a basic group and a triazine skeleton in one molecule, more preferably a compound having a nitrogen-containing heterocycle and a triazine skeleton in one molecule, and preferably a compound having a triazine skeleton and an imidazole structure in one molecule.
An example of the compound having a triazine skeleton and an imidazole structure is a compound represented by the following general formula (12).

In the general formula (12), R ¹¹ and R ¹² are each 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, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹³ 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. L ⁶ 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.

Specific examples of the imidazole compound having a triazine skeleton in this 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 and reaction temperature of the resin composition and the resin sheet.

(B2) Coupling Agent The (B2) coupling agent (hereinafter sometimes simply referred to as "(B2)") is preferably a compound such as the following.
The coupling agent (B2) preferably has a group that reacts with a functional group of the compound contained in the resin component (A). By using the coupling agent (B2), the peel strength between the cured resin sheet and the adherend is improved.

As the coupling agent (B2), a silane-based (silane coupling agent) is preferable because of its ease of handling. The coupling agent (B2) may be used alone or in combination of two or more kinds.
Examples of the silane coupling agent include a silane coupling agent having an amino group, a silane coupling agent having a mercapto group, and a silane coupling agent having an epoxy group.
Examples of silane coupling agents having an amino group include 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldiethoxymethylsilane, [3-(N,N-dimethylamino)propyl]trimethoxysilane, and [3-(phenylamino)propyl]trimethoxysilane.
Examples of the silane coupling agent having a mercapto group include 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane.
Examples of silane coupling agents having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.
Among these compounds, from the viewpoint of the peel strength of the resin composition and the resin sheet, a silane coupling agent having an epoxy group is more preferable, and 3-glycidoxypropyltrimethoxysilane is even more preferable.

The adhesion promoter (B) is preferably present in a total content of 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more, per 100 parts by mass of the total content of (A) and (B). It is also preferably present in a total content of 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 8 parts by mass or less. By setting the content in this range, the peel strength between the cured resin sheet and the adherend is improved.

It is more preferable to use (B) the adhesion promoter in combination with (B1) a compound having a triazine skeleton and (B2) a coupling agent. By using them in combination, the peel strength of the resin composition after curing can be further improved.

When (B1) a compound having a triazine skeleton is used as the adhesion promoter (B), the content of (B1) is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1.0 parts by mass or more, relative to 100 parts by mass of the total content of (A) and (B). It is also preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 8 parts by mass or less. By setting it in such a range, the peel strength between the cured resin sheet and the adherend is improved.

When a coupling agent (B2) is used as an adhesion promoter (B), the content of (B2) is preferably 0.05 parts by mass or more, more preferably 0.10 parts by mass or more, and even more preferably 0.50 parts by mass or more, per 100 parts by mass of the total content of (A) and (B). It is also preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 5 parts by mass or less. By setting it in such a range, the peel strength between the cured resin sheet and the adherend is improved.

In the present embodiment, the resin composition preferably contains, in addition to (A) and (B), an inorganic filler (C) (hereinafter, sometimes simply referred to as "(C)") This (C) can improve at least one of the thermal properties and the mechanical properties of the resin composition.
(C) Examples of the inorganic filler include silica filler, alumina filler, boron nitride filler, polytetrafluoroethylene filler, etc. Among these, silica filler is preferred.
Examples of the silica filler include fused silica and spherical silica.
The inorganic filler (C) may be used alone or in combination of two or more. The inorganic filler (C) may be surface-treated.

The average particle size of the inorganic filler (C) is not particularly limited. The average particle size of (C) is preferably 0.1 nm or more, more preferably 10 nm or more, and particularly preferably 1 μm or more. The upper limit of the average particle size of (C) is preferably 100 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less. In this specification, the average particle size of (C) is a value measured by a laser diffraction particle size distribution analyzer.

The content of the inorganic filler (C) in the resin composition is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 40% by mass or more, and particularly preferably 60% by mass or more, based on the total amount of solids in the resin composition (i.e., when the total amount of non-volatile content of the resin composition excluding the solvent is taken as 100% by mass). The upper limit of the content of (C) is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.
By setting the content of the (C) inorganic filler in the resin composition within the above range, the linear expansion coefficient of the resin composition can be reduced, and for example, the difference in the linear expansion coefficient between the encapsulated object such as silicon carbide and the resin composition or resin sheet can be reduced.

(D) Curing catalyst In the resin sheet according to the present embodiment, when the resin composition contains a resin component, it may further contain (D) a curing catalyst as long as the object of the present invention is not impaired. This makes it possible to effectively advance the curing reaction of the resin component, and makes it possible to cure the resin sheet well. Examples of the curing catalyst include imidazole-based curing catalysts, amine-based curing catalysts, phosphorus-based curing catalysts, triazole-based curing catalysts, thiazole-based curing catalysts, radical polymerization initiators, etc.

Specific examples of imidazole-based curing catalysts include 2-methylimidazole, 2-undecylimidazole, 2-heptadecylimidazole, 2-ethyl-4-methylimidazole, 1-benzyl-2-methylimidazole, 2-phenylimidazole, 2-phenyl-4-methylimidazole, 1-benzyl-2-phenylimidazole, 1,2-dimethylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecylimidazole, 1-cyanoethyl-2-phenylimidazole, 2-phenyl-4-methyl-5-hydroxymethylimidazole, and 2-phenyl-4,5-di(hydroxymethyl)imidazole. From the viewpoint of reactivity, it is preferable to use 2-ethyl-4-methylimidazole. In addition, when a compound having a triazine skeleton and an imidazole structure is used as the adhesion imparting agent (B) described above, it also acts as a curing catalyst.

Specific examples of amine-based curing catalysts include tertiary amine compounds such as 1,8-diazabicyclo[5,4,0]undecene-7 (DBU), 1,4-diazabicyclo[2.2.2]octane, and N,N-dimethylbenzylamine triethylamine.

Specific examples of phosphorus-based curing catalysts include triphenylphosphine, tributylphosphine, tri(p-methylphenyl)phosphine, and tri(nonylphenyl)phosphine.

Specific examples of triazole-based curing catalysts include benzotriazole-based compounds.

Specific examples of thiazole-based curing catalysts include benzothiazole-based compounds.

Specific examples of radical polymerization initiators include peroxides and azo compounds.

These (D) curing catalysts may be used alone or in combination of two or more. When (D) curing catalysts are used, the content of these is preferably 15 parts by mass or less, more preferably 12 parts by mass or less, and particularly preferably 8 parts by mass or less, when the total content of (A) is 100 parts by mass.

(E) Other Components In the present embodiment, the resin composition may further contain (E) other components, as long as the object of the present invention is not impaired. Examples of (E) other components include at least one component selected from the group consisting of a coloring material, an antifoaming agent, a leveling agent, an ultraviolet absorber, a foaming agent, an antioxidant, a flame retardant, an ion trapping agent, and an ion capturing agent.
These (E) other components can be used alone or in combination of two or more. When (E) other components are used, the content of these components is preferably 10 parts by mass, and more preferably 5 parts by mass or less, when the total content of (A) is 100 parts by mass.

In this embodiment, when the resin sheet is formed by coating, the resin composition preferably contains a solvent. Examples of the solvent include common solvents such as toluene, ethyl acetate, and methyl ethyl ketone, as well as high-boiling point solvents such as cyclohexanone (boiling point: 155.6°C), dimethylformamide (boiling point: 153°C), dimethyl sulfoxide (boiling point: 189.0°C), ethers of ethylene glycol (cellosolve) (boiling point: approximately 120 to 310°C), and ortho-xylene (boiling point: 144.4°C).

[Resin sheet]
The resin sheet according to the present embodiment is formed from the resin composition according to the present embodiment described above. In the resin sheet according to the present embodiment, the embedding property can be improved while maintaining the heat resistance. Therefore, for example, when sealing a semiconductor element with a resin sheet, even if there is a gap in the structure in which the semiconductor element is arranged, the resin sheet can be used to embed the gap.

The peel strength of the resin sheet according to the present embodiment after heat curing is preferably 2.0 N/10 mm or more, more preferably 3.0 N/10 mm or more, even more preferably 4.0 N/10 mm or more, and particularly preferably 6.0 N/10 mm or more. The upper limit of the peel strength after heat curing is preferably 50 N/10 mm or less, and particularly preferably 40 N/10 mm or less.
If the peel strength of the resin sheet according to this embodiment after thermal curing is 2.0 N/10 mm or more, when the resin sheet is used as a sealing material, it is possible to maintain high adhesion to an adherend.
The peel strength of the resin sheet according to this embodiment after thermal curing can be adjusted to the above range, for example, by selecting the components to be used in the resin composition, preferably by blending at least one selected from an allyl resin and an adhesion imparting agent into the resin composition, and adjusting the type and amount of the component.
The peel strength of the resin sheet according to the present embodiment after thermal curing was determined by performing a peel test at a peel angle of 90 degrees between the resin sheet after thermal curing and the adherend using the measurement method described below. Specifically, a test piece was prepared as described in the examples, and the peel test was performed.
In the resin sheet according to this embodiment, the resin composition is formed into a sheet, which makes it easy to apply to an adherend, and particularly easy to attach to an adherend having a large area.
If the resin composition is in a sheet form, it is preformed into a shape that matches the shape after the sealing process, so that it can be supplied as a sealing material that maintains a certain degree of uniformity simply by applying it. In addition, if the resin composition is in a sheet form, it has no fluidity and is therefore easy to handle.

The method of forming the resin composition into a sheet can be a conventionally known method, and is not particularly limited. When forming a resin sheet from the resin composition by applying a resin composition containing a solvent, the solvent may be completely evaporated in a drying process after application, or a portion of the solvent may remain in the resin sheet. The resin sheet according to the present embodiment may be a strip-shaped sheet, or may be provided in a rolled-up state. The resin sheet according to the present embodiment that has been rolled up can be used by being unwound from the roll and cut to a desired size, for example.

The thickness of the resin sheet according to this embodiment is, for example, preferably 10 μm or more, and more preferably 20 μm or more. The thickness is also preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less.

The resin sheet according to the present embodiment is preferably used for a semiconductor element. Specifically, the resin sheet according to the present embodiment is preferably used for sealing the semiconductor element. In addition, the resin sheet according to the present embodiment is preferably used for being interposed between the semiconductor element and other electronic components.
The semiconductor element is preferably a power semiconductor element.
Since the resin sheet according to this embodiment has excellent heat resistance, it can be used to seal power semiconductor elements that are expected to operate at high temperatures of 200°C or higher, or to be interposed between the power semiconductor elements and other electronic components.

The resin sheet according to this embodiment is preferably applied to multiple semiconductor elements all at once. For example, the resin sheet according to this embodiment can be used in a so-called panel level package, in which a resin sheet is applied to a structure in which a semiconductor element is arranged in each gap of a frame having multiple gaps, and the frame and the semiconductor elements are sealed together.

In addition, the resin sheet according to this embodiment is preferably used to seal a semiconductor element using at least one of silicon carbide and gallium nitride. Alternatively, the resin sheet according to this embodiment is preferably used to be interposed between a semiconductor element using at least one of silicon carbide and gallium nitride and another electronic component. Examples of other electronic components include a printed wiring board and a lead frame.
Since the upper limit of the operating temperature of silicon semiconductor elements is about 175° C., it is preferable to use, as the power semiconductor element, a semiconductor element using at least one of silicon carbide and gallium nitride, which are capable of operating at high temperatures.
The resin sheet according to this embodiment has excellent heat resistance, and can therefore be used to encapsulate semiconductor elements using one or more of silicon carbide and gallium nitride that are expected to operate at high temperatures of 200°C or higher, or to be interposed between a semiconductor element using one or more of silicon carbide and gallium nitride and other electronic components.

(Heat curing conditions)
In the thermal curing conditions for the resin sheet according to this embodiment, the heating temperature is preferably 50° C. or more and 300° C. or less, and more preferably 100° C. or more and 250° C. or less.
In the thermal curing conditions for the resin sheet according to this embodiment, the heating time is preferably from 10 minutes to 10 hours, and more preferably from 20 minutes to 7 hours.
By setting the heat curing conditions for the resin sheet within the above ranges, heat curing of the resin sheet can be achieved.

[Laminate]
FIG. 1 shows a schematic cross-sectional view of a laminate 1 according to this embodiment.
The laminate 1 according to this embodiment has 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 according to this embodiment.

The first release material 2 and the second release material 4 have release properties, and it is preferable that there is a difference between the release force of the first release material 2 against the resin sheet 3 and the release force of the second release material 4 against the resin sheet 3. The materials of the first release material 2 and the second release material 4 are not particularly limited. It is preferable that the ratio (P2/P1) of the release force P2 of the second release material 4 to the release force P1 of the first release material 2 is 0.02≦P2/P1<1 or 1<P2/P1≦50.

The first release material 2 and the second release material 4 may be, for example, a material that has a release property in itself, a material that has been subjected to a release treatment, a material on which a release agent layer is laminated, etc. When the first release material 2 and the second release material 4 have not been subjected to a release treatment, examples of the material for the first release material 2 and the second release material 4 include olefin resins, fluororesins, etc.
The first release material 2 and the second release material 4 can be a release material comprising a release substrate and a release agent layer formed on the release substrate. By forming the release material comprising a release substrate and a release agent layer, handling becomes easy. In addition, the first release material 2 and the second release material 4 may comprise a release agent layer on only one side of the release substrate, or may comprise a release agent layer on both sides of the release substrate. The release agent can be formed, for example, by coating the release agent.

Examples of the release substrate include paper substrate, laminated paper in which a thermoplastic resin such as polyethylene is laminated to the paper substrate, and plastic films. Examples of the paper substrate include glassine paper, coated paper, and cast-coated paper. Examples of the plastic film include polyester films (e.g., polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate), and polyolefin films (e.g., polypropylene and polyethylene). Of these, polyester films are preferred.

Examples of the release agent include silicone-based release agents made of silicone resins; long-chain alkyl group-containing compound-based release agents made of compounds containing long-chain alkyl groups, such as polyvinyl carbamates and alkyl urea derivatives; alkyd resin-based release agents made of alkyd resins (e.g., non-convertible alkyd resins and convertible alkyd resins); olefin resin-based release agents made 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 a syndiotactic structure, and crystalline polypropylene resins such as propylene-α-olefin copolymers); rubber-based release agents made 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 made of acrylic resins such as (meth)acrylic acid ester copolymers. These can be used alone or in combination of two or more. Of these, alkyd resin-based release agents are preferred.

There is no particular limitation on the thickness of the first release material 2 and the second release material 4. Generally, the thickness is from 1 μm to 500 μm, and preferably from 3 μm to 100 μm.
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 or more and 3 μm or less, and more preferably 0.03 μm or more and 1 μm or less.

The method for producing the laminate 1 is not particularly limited. For example, the laminate 1 is produced through the following steps. First, a resin composition containing a solvent is applied onto the first release material 2 to form a coating film. Next, this coating film is dried to form the resin sheet 3. Next, the resin sheet 3 and the second release material 4 are bonded together to obtain the laminate 1.

[Effects of the embodiment]
According to the resin sheet of this embodiment, a resin sheet capable of improving embeddability can be obtained.

As described above, the resin sheet according to this embodiment can be suitably used for power semiconductor elements. In other words, in the semiconductor device according to this embodiment, the semiconductor element is preferably a power semiconductor element. It is assumed that the power semiconductor element will operate at high temperatures of 200°C or higher. Therefore, heat resistance is required for materials used in semiconductor devices having power semiconductor elements. The resin sheet according to this embodiment has excellent heat resistance, and is therefore suitably used for covering the power semiconductor element in a semiconductor device, or for being interposed between the power semiconductor element and other components.

As described above, the resin sheet according to this embodiment can be suitably used for semiconductor elements using one or more of silicon carbide and gallium nitride. In other words, in the semiconductor device according to this embodiment, the semiconductor element is preferably a semiconductor element using one or more of silicon carbide and gallium nitride. Since a semiconductor element using one or more of silicon carbide and gallium nitride has characteristics different from those of a silicon semiconductor element, it is preferably used for applications such as power semiconductor elements, high-output devices for base stations, sensors, detectors, and Schottky barrier diodes. In these applications, attention is also paid to the heat resistance of semiconductor elements using one or more of silicon carbide and gallium nitride, and since the resin sheet according to this embodiment has excellent heat resistance, it is suitably used in combination with a semiconductor element using one or more of silicon carbide and gallium nitride.

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

In the above embodiment, a laminate having a first release material, a second release material, and a resin sheet disposed between the first release material and the second release material is described, but the laminate may also have a release material on only one side of the resin sheet.

In addition, although the semiconductor device embodiment has been described as being used for semiconductor encapsulation, the resin sheet of the present invention can also be used as an insulating material for circuit boards (e.g., materials for rigid printed wiring boards, materials for flexible wiring boards, and interlayer insulating materials for build-up boards), adhesive films for build-up boards, and adhesives, etc.

The present invention will be described in more detail below with reference to examples. The present invention is not limited to these examples.

[Preparation of resin composition]
The resin compositions according to Examples 1 to 5 and Comparative Example 1 were prepared by dissolving or dispersing each component in a solvent at the blending ratio (mass % (ratio converted to solid content)) shown in Table 1. The contents of (A), (B) and (C) in the examples and comparative example are shown in Table 1.
The materials used in the preparation of the resin composition are as follows:

(A1) First maleimide resin: BMI-3000: long-chain alkyl maleimide resin (maleimide resin represented by the general formula (5), "BMI-3000" manufactured by Designer Molecules Inc., solid at a temperature of 25°C)
BMI-1700: long-chain alkyl maleimide resin (maleimide resin represented by the general formula (6), "BMI-1700" manufactured by Designer Molecules Inc., liquid at a temperature of 25°C)
BMI-1500: long-chain alkyl maleimide resin (maleimide resin represented by the general formula (7), "BMI-1500" manufactured by Designer Molecules Inc., liquid at a temperature of 25°C)
(A2) Second maleimide resin: MIR-3000: a maleimide resin having a biphenyl group (maleimide resin represented by the general formula (3) above, "MIR-3000" manufactured by Nippon Kayaku Co., Ltd.)
(A3) Allyl resin/DABPA: Diallyl bisphenol A ("DABPA" manufactured by Daiwa Chemical Industry Co., Ltd.)
(A4) Other resin components YX7200: BisA type phenoxy resin ("YX7200" manufactured by Mitsubishi Chemical Corporation)

(B1) Compound having a triazine skeleton 2E4MZ-A: 2,4-diamino-6-[2-(2-ethyl-4-methyl-1-imidazolyl)ethyl]-1,3,5-triazine ("2E4MZ-A" manufactured by Shikoku Chemical Industry Co., Ltd.)
(B2) Coupling agent: KBM403: 3-glycidoxypropyltriethoxysilane ("KBM403" manufactured by Shin-Etsu Chemical Co., Ltd.)

(C) Inorganic filler/silica filler: silica filler dispersion ("SC2050-HLJ" manufactured by Admatechs Co., Ltd., average particle size 0.50 μm)

<Evaluation of Resin Composition and Resin Sheet>
[Preparation of laminate including resin sheet]
A resin varnish (a coating solution in which each component of the resin composition is dissolved or dispersed in cyclohexanone, solid content concentration is 60% by mass) was applied to a release sheet 1 (a polyethylene terephthalate film provided with a release layer formed from an alkyd resin-based release agent, manufactured by Lintec Corporation, "PET38AL-5", thickness 38 μm) as a first release material using a knife coater, and dried at 100 ° C. for 1 minute, and then dried at 110 ° C. for 1 minute. The thickness of the resin composition after drying was 30 μm. Immediately after removing from the drying oven, the dried resin composition and a release sheet 2 (a polyethylene terephthalate film provided with a release layer formed from a silicone-based release agent, manufactured by Lintec Corporation, "SP-PET382150", thickness 38 μm) as a second release material were bonded together to produce a laminate in which the first release material, the resin sheet made of the resin composition, and the second release material were laminated in this order.

[Embeddability]
A copper-clad laminate (Hitachi Chemical Co., Ltd., "MCL-E-705G", thickness 200 μm) was etched to obtain a substrate with markers (copper) formed near each vertex on both sides. The substrate thus obtained was processed to form a square through hole of 4.56 mm x 4.56 mm using a router processing machine, to produce a frame 5 as shown in FIG. 2(a). In addition, as shown in FIG. 2(a), an adhesive tape 6 (Lintec Corporation, "ADWILL H-231F") was attached to one side 5α of the frame 5, and then, as shown in FIG. 2(b), the mirror-polished surface of a square mirror-polished chip 7 (size 4.26 mm x 4.26 mm, thickness 200 μm) was mounted on the adhesive surface exposed from the hole using a mounting machine (Panasonic Factory Solutions Co., Ltd., "NM-EJM1D"). Next, the resin sheet 3 (thickness 30 μm) from which the second release material was peeled off was placed on the opposite surface 5β of the frame 5, and the opposite surface 5β of the frame 5 was sealed by vacuum pressure bonding using a laminating device (manufactured by Nikko Materials Co., Ltd., "V-130") under conditions of lamination temperature 130 ° C., ultimate pressure 100 Pa, and time 60 seconds. Next, the first release material of the resin sheet 3 was peeled off, and the sealed frame and chip 7 were placed in the state shown in FIG. 2 (c), and heated at a temperature of 180 ° C. for 1 hour, after which the adhesive tape 6 was peeled off to the state shown in FIG. 2 (d), and the resin sheet 3 (thickness 30 μm) was placed on the peeled surface, and the laminate was used to bond them together under the same conditions as above, and the resin sheet 3 was thermally cured at a temperature of 200 ° C. for 4 hours to seal one side 5α of the frame 5 to the state shown in FIG. 2 (e). Finally, using a dicing machine (DISCO Corporation's "DFD6362"), the substrate was divided into squares measuring 6 mm x 6 mm with the chip 7 at the center, as shown in Fig. 2(f), to obtain a package component 8 as shown in Fig. 3. Then, the following embeddability evaluation was performed using the package component 8 as a test piece.
First, the test piece was embedded in acrylic resin, and the cross section of the center of the test piece was exposed by polishing. The cross section was observed with a digital microscope ("VHX-5000" manufactured by Keyence Corporation). The gap between the frame 5 and the chip 7 shown in FIG. 3 was observed. The width w of the gap was 100 μm, and the thickness t of the chip 7 was 200 μm.
Next, the obtained digital image (JPEG format) of the cross section was colored in red using the image editing and processing software "GIMP" (free software) to color the part embedded by the first sealing (see FIG. 2(c)). The part embedded by the first sealing is thermally cured twice, so it can be distinguished from the part embedded by the second sealing because it is a different color. Then, using the color information function, the embedding area ratio (unit: %) of the colored part was calculated when the gap between the frame 5 and the chip 7 was set to 100% (w x t is set to 100%). The larger this embedding area ratio, the better the embedding property. Based on this embedding area ratio, the embedding property was evaluated according to the following criteria. The results are shown in Table 1.
A: The embedding area ratio is 90% or more.
B: The embedding area ratio is 60% or more and less than 90%.
F: The embedding area ratio is less than 60%.

The results shown in Table 1 confirm that when the content of (A1) in the resin component is 30% by mass or more and 58% by mass or less (Examples 1 to 5), the embeddability is excellent.

1...Laminate, 2...First release material, 3...Resin sheet, 4...Second release material, 5...Frame, 6...Adhesive tape, 7...Chip, 8...Package part, 5α...One side of frame, 5β...Other side of frame, w...Width of gap, t...Thickness of chip.

Claims (12)

(A) A resin sheet formed from a resin composition containing a resin component,
The (A) resin component contains (A1) a first maleimide resin,
the (A1) first maleimide resin is a maleimide resin having two or more maleimide groups in one molecule, and a bonding group connecting at least one pair of two maleimide groups has four or more methylene groups in a main chain;
The content of the first maleimide resin (A1) is 30% by mass or more and 58% by mass or less when the total amount of the resin component (A) in the resin composition is 100% by mass.
Resin sheet. The resin sheet according to claim 1,
The (A) resin component further contains (A2) a second maleimide resin,
The second maleimide resin (A2) is a maleimide resin having a chemical structure different from that of the first maleimide resin (A1).
Resin sheet. The resin sheet according to claim 1 or 2,
The second maleimide resin (A2) is a maleimide resin containing two or more maleimide groups and two or more phenylene groups in one molecule.
Resin sheet. The resin sheet according to any one of claims 1 to 3,
The resin composition further contains (B) a compound having an adhesion imparting agent.
Resin sheet. The resin sheet according to claim 4,
The adhesion promoter (B) contains a compound (B1) having a triazine skeleton.
Resin sheet. The resin sheet according to claim 5 ,
The adhesion imparting agent (B) is a compound (B1) having a basic group and a triazine skeleton in one molecule.
Resin sheet. The resin sheet according to claim 6,
The adhesion promoter (B) is a compound having a triazine skeleton and an imidazole structure in one molecule.
Resin sheet. The resin sheet according to any one of claims 1 to 7,
The adhesion imparting agent (B) contains a coupling agent (B2).
Resin sheet. The resin sheet according to any one of claims 1 to 8,
The (A) resin component further contains (A3) an allyl resin.
Resin sheet. The resin sheet according to any one of claims 1 to 9,
The resin sheet is used to fill a gap.
Resin sheet. The resin sheet according to any one of claims 1 to 10,
The resin sheet is used to encapsulate a semiconductor element or to be interposed between a semiconductor element and another electronic component.
Resin sheet. The resin sheet according to claim 11,
The resin sheet is used to encapsulate a plurality of semiconductor chips at once.
Resin sheet.

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