thermosetting resin composition

Abstract

To provide a new thermosetting resin composition from which a cured product that exhibits a low dielectric loss tangent under room temperature environment, suppresses a rise of a dielectric loss tangent even under high temperature environment, and exhibits a good dielectric loss tangent can be given.SOLUTION: A thermosetting resin composition contains (A) a monofunctional epoxy resin represented by the following formula (1), and (B) a radical-polymerizable compound. In the formula (1), R represents a monovalent aliphatic group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to thermosetting resin compositions, and more particularly to resin sheets, cured products, circuit boards, and semiconductor devices. [Background technology]

[0002] Insulating materials for circuit boards, such as printed circuit boards and redistribution boards for semiconductor chip packages, are required to exhibit good dielectric properties (low dielectric constant, low dielectric loss tangent) in order to suppress transmission loss when operating in high-frequency environments. Known insulating materials that exhibit good dielectric properties include insulating materials containing radical polymerizable compounds (for example, Patent Document 1) and insulating materials containing active ester resins as curing agents for epoxy resins (for example, Patent Document 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2017-71798 [Patent Document 2] Japanese Patent Publication No. 2009-235165 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] With the increasing speed of communications in recent years, insulating materials for circuit boards are required to exhibit even better dielectric properties. Furthermore, semiconductor devices may be exposed to high-temperature environments, such as when operating in high-frequency environments. We have found that even materials that exhibit good dielectric properties at room temperature may experience deterioration in dielectric properties (especially dielectric loss tangent) at high temperatures, and may not achieve the desired dielectric properties in actual usage environments.

[0005] The object of the present invention is to provide a novel thermosetting resin composition that yields a cured product exhibiting a low dielectric loss tangent at room temperature and suppressing the increase in dielectric loss tangent even at high temperatures, thereby exhibiting a good dielectric loss tangent. [Means for solving the problem]

[0006] As a result of diligent research, the inventors of the present invention have found that the above problems can be solved by a thermosetting resin composition having the following configuration, and have completed the present invention.

[0007] In other words, the present invention includes the following: <1> (A) A monofunctional epoxy resin represented by the following formula (1), and (B) a thermosetting resin composition comprising a radical polymerizable compound. [ka] (In formula (1), R represents a monovalent aliphatic group.) <2> Furthermore, (E) including inorganic fillers, <1> The thermosetting resin composition described in [reference]. <3> When the resin component in the thermosetting resin composition is considered to be 100% by mass, the content of component (A) is 0.5 to 20% by mass. <1> or <2> The thermosetting resin composition described in [reference]. <4> When the resin component in the thermosetting resin composition is considered to be 100% by mass, the content of component (B) is 1 to 70% by mass. <1> ~ <3> A thermosetting resin composition as described in any of the above. <5> When the nonvolatile components in the thermosetting resin composition are considered to be 100% by mass, the content of component (E) is 40% by mass or more. <2> ~ <4> A thermosetting resin composition as described in any of the above. <6> In equation (1), R is expressed by the following equation (2): <1> ~ <5> A thermosetting resin composition as described in any of the above. [ka] (In formula (2), R 1 This represents a monovalent aliphatic group, R 2 and R 3 Each of these independently represents a divalent aliphatic group. X represents -C(=O)-O-, or -O-. n1 represents a number between 0 and 50. n2 and n3 each independently represent either 0 or 1. <7> Furthermore, it contains epoxy resins other than component (A), <1> ~ <6> A thermosetting resin composition as described in any of the above. <8> When the total epoxy resin is considered to be 100% by mass, the content of component (A) is 1% by mass or more. <7> The thermosetting resin composition described in [reference]. <9> The mass ratio of component (A) to component (B) (component (A) / component (B)) is 0.01 or greater. <1> ~ <8> A thermosetting resin composition as described in any of the above. <10> It is for the insulating layer of a circuit board. <1> ~ <9> A thermosetting resin composition as described in any of the above. <11> A support and provided on the support <1> ~ <10> A resin sheet comprising a layer of a thermosetting resin composition as described in any of the above. <12> The support is a thermoplastic resin film or a metal foil. <11> The resin sheet described above. <13> <1> ~ <10> A cured product of a thermosetting resin composition as described in any of the above. <14> <1> ~ <10> A circuit board comprising an insulating layer made of a cured product of a thermosetting resin composition described in any of the above. <15> <14> A semiconductor device including the circuit board described above. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a novel thermosetting resin composition that exhibits a low dielectric loss tangent at room temperature and suppresses the increase in dielectric loss tangent even at high temperatures, resulting in a cured product that exhibits a good dielectric loss tangent. [Modes for carrying out the invention]

[0009] <Explanation of Terms> In this specification, the term "aliphatic group" refers to a group obtained by removing one or more hydrogen atoms from an aliphatic compound. More specifically, a monovalent aliphatic group refers to a group obtained by removing one hydrogen atom from an aliphatic compound, and a divalent aliphatic group refers to a group obtained by removing two hydrogen atoms from an aliphatic compound. Here, the aliphatic compound may be a heteroatom-free aliphatic compound composed only of carbon atoms and hydrogen atoms, or it may be a heteroatom-containing aliphatic compound composed of carbon atoms, hydrogen atoms, and heteroatoms. In this specification, the term "heteroatom" refers to an atom other than carbon atoms and hydrogen atoms, such as oxygen atoms, nitrogen atoms, sulfur atoms, silicon atoms, halogen atoms, etc.

[0010] In this specification, the term "aliphatic hydrocarbon group" refers to a group obtained by removing one or more hydrogen atoms from a heteroatom-free aliphatic compound composed only of carbon atoms and hydrogen atoms. More specifically, a monovalent aliphatic hydrocarbon group refers to a group obtained by removing one hydrogen atom from a heteroatom-free aliphatic compound, and a divalent aliphatic group refers to a group obtained by removing two hydrogen atoms from a heteroatom-free aliphatic compound. Examples of monovalent aliphatic hydrocarbon groups include optionally substituted alkyl groups, optionally substituted cycloalkyl groups, optionally substituted alkenyl groups, optionally substituted cycloalkenyl groups, and optionally substituted alkapolienyl groups (preferably 2 to 10, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 double bonds). Examples of divalent aliphatic hydrocarbon groups include optionally substituted alkylene groups, optionally substituted cycloalkylene groups, optionally substituted alkenylene groups, optionally substituted cycloalkenylene groups, and optionally substituted alkapolienylene groups (preferably 2 to 10, more preferably 2 to 6, even more preferably 2 to 4, and even more preferably 2 double bonds). Here, alkyl groups, alkenyl groups, alkapolienyl groups, alkylene groups, alkenylene groups, and alkapolienylene groups may be linear or branched. In this specification, unless otherwise specified, the number of carbon atoms in an aliphatic hydrocarbon group is preferably 1 or more, more preferably 2 or more or 3 or more, preferably 100 or less, more preferably 80 or less, and even more preferably 60 or less, 50 or less, or 40 or less. The number of carbon atoms in substituents is not included in this number of carbon atoms.

[0011] In this specification, the term "heteroatom-containing aliphatic group" means a group obtained by removing one or more hydrogen atoms from an aliphatic compound containing a heteroatom. More specifically, a monovalent heteroatom-containing aliphatic group means a group obtained by removing one hydrogen atom from an aliphatic compound containing a heteroatom, and a divalent heteroatom-containing aliphatic group means a group obtained by removing two hydrogen atoms from an aliphatic compound containing a heteroatom. In the "heteroatom-containing aliphatic group" as used herein, the heteroatom may be bonded to any of the carbon atoms constituting the group, for example, (i) interposed between carbon-carbon bonds, or (ii) bonded to a terminal carbon. Also, in the "heteroatom-containing aliphatic group" as used herein, the bond may extend from a carbon atom or from the heteroatom. The heteroatom-containing aliphatic group may be saturated or unsaturated, and may have a cyclic structure. Examples of monovalent heteroatom-containing aliphatic groups include optionally substituted heteroalkyl groups, optionally substituted heteroalkenyl groups, optionally substituted heteroalkynyl groups, optionally substituted heteroalcapopolyenyl groups, and optionally substituted monovalent aliphatic heterocyclic groups. Other examples of monovalent heteroatom-containing aliphatic groups include monovalent groups formed by bonding a divalent group selected from the group consisting of -O-, -S-, -C(=O)-, -S(=O)-, -S(=O)2-, -N(R')-, -Si(R')2-, and combinations thereof to a bond of a monovalent aliphatic carbocyclic group or a monovalent aliphatic heterocyclic group (wherein R' represents a hydrogen atom or a substituent as described below; the same applies hereafter). In this specification, unless otherwise specified, the number of heteroatoms in a heteroatom-containing aliphatic group is preferably 1 or more, 2 or more, or 3 or more, preferably 30 or less, 25 or less, or 20 or less, and unless otherwise specified, the number of carbon atoms is preferably 1 or more, more preferably 2 or more, or 3 or more, preferably 100 or less, more preferably 80 or less, and even more preferably 60 or less, 50 or less, or 40 or less. The number of heteroatoms and carbon atoms of substituents is not included in the number of heteroatoms and carbon atoms.

[0012] In this specification, the term "heteroalkyl group" refers to a monovalent saturated aliphatic group containing a heteroatom, which may be linear or branched. The number of heteroatoms and carbon atoms of the heteroalkyl group is as described for "heteroatom-containing aliphatic groups," but the number of heteroatoms is preferably 1 to 20, more preferably 1 to 16, and the number of carbon atoms is preferably 1 to 50, more preferably 1 to 45. In the heteroalkyl group, the heteroatom is preferably one or more selected from the group consisting of oxygen, nitrogen, sulfur, and silicon atoms, and may exist as heteroatoms such as -O-, -S-, or as heteroatom-containing groups such as -C(=O)-, -S(=O)-, -S(=O)2-, -N(R')-, -Si(R')2-, combinations thereof, or combinations of these with -O-, -S-. If the heteroalkyl group contains two or more heteroatoms, they may be the same or different from each other. As mentioned above, the heteroatom may be interposed between carbon-carbon bonds or bonded to a terminal carbon. Examples of the heteroalkyl group include alkyloxy groups (alkoxy groups), alkylthio groups, alkylsulfonyl groups, alkylsulfinyl groups, alkylcarbonyl groups, alkylamino groups, alkylsilyl groups, alkyloxycarbonyl groups, and alkylcarbonyloxy groups, in which the heteroatom is bonded to a terminal carbon; and examples of the heteroatom interposed between carbon-carbon bonds include monovalent saturated aliphatic groups that are divided by one or more divalent groups selected from the group consisting of -O-, -S-, -C(=O)-, -S(=O)-, -S(=O)2-, -N(R')-, -Si(R')2-, and combinations thereof.

[0013] In this specification, the term "heteroalkenyl group" refers to a monovalent unsaturated aliphatic group containing a heteroatom and having one carbon-carbon double bond, and may be linear or branched. The number of heteroatoms and carbon atoms of the heteroalkenyl group is as described for "heteroatom-containing aliphatic groups," but the number of heteroatoms is preferably 1 to 20, more preferably 1 to 16, and the number of carbon atoms is preferably 2 to 50, more preferably 2 to 45. The preferred types of heteroatoms and their positions in the group are as described for "heteroalkyl groups" above. Preferred examples of the heteroalkenyl group can be applied by substituting "alkyl" for "alkenyl" and "monovalent saturated aliphatic group" for "monovalent unsaturated aliphatic group having one carbon-carbon double bond" in the examples given for "heteroalkyl groups" above.

[0014] In this specification, the term "heteroalkynyl group" refers to a monovalent unsaturated aliphatic group containing a heteroatom and having one carbon-carbon triple bond, and may be linear or branched. The number of heteroatoms and carbon atoms of the heteroalkynyl group is as described for "heteroatom-containing aliphatic groups," but the number of heteroatoms is preferably 1 to 20, more preferably 1 to 16, and the number of carbon atoms is preferably 2 to 50, more preferably 2 to 45. The preferred types of heteroatoms and their positions in the group are as described for "heteroalkyl groups" above. Preferred examples of the heteroalkynyl group can be applied by substituting "alkyl" for "alkynyl" and "monovalent saturated aliphatic group" for "monovalent unsaturated aliphatic group having one carbon-carbon triple bond" in the examples given for "heteroalkyl groups" above.

[0015] In this specification, the term "heteroalkaporenyl group" refers to a monovalent unsaturated aliphatic group containing a heteroatom and having two or more carbon-carbon double bonds, and may be linear or branched. The number of heteroatoms and carbon atoms of the heteroalkaporenyl group is as described for "heteroatom-containing aliphatic group," but the number of heteroatoms is preferably 1 to 20, more preferably 1 to 16, and the number of carbon atoms is preferably 3 to 50, more preferably 3 to 45. A suitable example of the heteroalkaporenyl group can be applied by replacing "alkyl" with "alkaporenyl" and "monovalent saturated aliphatic group" with "monovalent unsaturated aliphatic group having two or more carbon-carbon double bonds" in the example given for "heteroalkyl group" above.

[0016] In this specification, the term "monovalent aliphatic carbocyclic group" refers to a group obtained by removing one hydrogen atom from an aliphatic cyclic hydrocarbon. Here, the aliphatic carbocyclic group may be either an aliphatic saturated carbocyclic group or an aliphatic unsaturated carbocyclic group, and may be a monocyclic aliphatic carbocyclic group, a condensed polycyclic aliphatic carbocyclic group formed by the condensation of two or more monocyclic aliphatic carbocyclic groups, or a spirocyclic aliphatic carbocyclic group formed by the spirobonding of two or more monocyclic aliphatic carbocyclic groups. The number of carbon atoms in the monovalent aliphatic carbocyclic group is as described for the "aliphatic hydrocarbon group," but is preferably 3 to 20, more preferably 3 to 15, even more preferably 3 to 14, 3 to 12, 3 to 10, 3 to 7, or 3 to 6. Examples of the monovalent carbon ring group include cycloalkyl groups as monovalent aliphatic saturated carbon ring groups, and cycloalkenyl groups, cycloalkynyl groups, and cycloalkaporenyl groups as monovalent aliphatic unsaturated carbon ring groups.

[0017] In this specification, the term "monovalent aliphatic heterocyclic group" refers to a group obtained by removing one hydrogen atom from an aliphatic heterocyclic compound. Here, the aliphatic heterocyclic group may be either an aliphatic saturated heterocyclic group or an aliphatic unsaturated heterocyclic group, and may be a monocyclic aliphatic heterocyclic group, a fused polycyclic aliphatic heterocyclic group, or a spirocyclic aliphatic heterocyclic group. The number of heteroatoms and carbon atoms of the monovalent aliphatic heterocyclic group is as described for "heteroatom-containing aliphatic groups," but the number of heteroatoms is preferably 1 to 10, more preferably 1 to 8, even more preferably 1 to 6, or 1 to 4. The number of ring members of the monovalent aliphatic heterocyclic group is preferably 5 to 20, more preferably 5 to 15, even more preferably 5 to 12, or 5 to 10. In the monovalent aliphatic heterocyclic group, the heteroatoms are preferably one or more selected from the group consisting of oxygen atoms, nitrogen atoms, and sulfur atoms.

[0018] In this specification, the term “may have substituents” with respect to a compound or group means both cases where the hydrogen atoms of the compound or group are not substituted with substituents, and cases where some or all of the hydrogen atoms of the compound or group are substituted with substituents.

[0019] In this specification, the term "substituent" means, unless otherwise specified, a halogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an alkoxy group, a cycloalkyloxy group, an alkylthio group, a cycloalkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, a monovalent aliphatic heterocyclic group, an alkylidene group, an acyl group, an acyloxy group, an amino group, a silyl group, a carboxyl group, a sulfo group, a cyano group, a nitro group, a mercapto group, and an oxo group.

[0020] Examples of halogen atoms used as substituents include fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms. The alkyl group used as a substituent may be linear or branched. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 3. The alkenyl group used as a substituent may be linear or branched. The number of carbon atoms in the alkenyl group is preferably 2 to 12, more preferably 2 to 6, and even more preferably 2 or 3. The number of carbon atoms in the cycloalkyl group used as a substituent is preferably 3 to 12, more preferably 3 to 6. The alkoxy group used as a substituent may be linear or branched. The number of carbon atoms in the alkoxy group is preferably 1 to 12, more preferably 1 to 6. The number of carbon atoms in the cycloalkyloxy group used as a substituent is preferably 3 to 12, more preferably 3 to 6. The alkylthio group used as a substituent may be linear or branched. The number of carbon atoms in the alkylthio group is preferably 1 to 12, more preferably 1 to 6. The number of carbon atoms in the cycloalkylthio group used as a substituent is preferably 3 to 12, more preferably 3 to 6. The number of carbon atoms in the aryl group used as a substituent is preferably 6 to 14, more preferably 6 to 10. The number of carbon atoms in the aryloxy group used as a substituent is preferably 6 to 14, more preferably 6 to 10. The number of carbon atoms in the arylthio group used as a substituent is preferably 6 to 14, more preferably 6 to 10. The number of carbon atoms in the arylalkyl group used as a substituent is preferably 7 to 15, more preferably 7 to 11. The number of carbon atoms in the arylalkoxy group used as a substituent is preferably 7 to 15, more preferably 7 to 11. A monovalent aliphatic heterocyclic group used as a substituent refers to a group obtained by removing one hydrogen atom from an aliphatic heterocyclic compound. The number of carbon atoms in the monovalent aliphatic heterocyclic group is preferably 3 to 15, more preferably 3 to 9. An alkylidene group used as a substituent refers to a group obtained by removing two hydrogen atoms from the same carbon atom of an alkane.The number of carbon atoms in the alkylidene group is preferably 1 to 12, more preferably 1 to 6, and particularly preferably 1 to 3. The acyl group used as a substituent has the formula: -C(=O)-R. S a group represented by (wherein, R S is an alkyl group). The alkyl group represented by R S may be either linear or branched. The number of carbon atoms in the acyl group is preferably 2 to 13, more preferably 2 to 7. The acyloxy group used as a substituent has the formula: -O-C(=O)-R S a group represented by (wherein, R S has the same meaning as described above). The number of carbon atoms in the acyloxy group is preferably 2 to 13, more preferably 2 to 7. The above-mentioned substituents may further have a substituent (sometimes referred to as a "secondary substituent"). As the secondary substituent, the same ones as the above-mentioned substituents may be used unless otherwise specified.

[0021] In this specification, the term "C p ~C q " (p and q are positive integers and p < q) indicates that the number of carbon atoms in the organic group described immediately after this term is p to q. For example, "C1~C 18 alkyl group" indicates an alkyl group having 1 to 18 carbon atoms, and "C1~C6 alkylene group" indicates an alkylene group having 1 to 6 carbon atoms.

[0022] Hereinafter, the present invention will be described in detail with reference to embodiments and examples. However, the present invention is not limited to the following embodiments and examples, and can be arbitrarily modified and implemented without departing from the scope of the claims of the present invention and its equivalent scope.

[0023] [Thermosetting resin composition] The thermosetting resin composition of the present invention is characterized by containing (A) a monofunctional epoxy resin represented by the following formula (1), and (B) a radically polymerizable compound.

[0024] [Chemical formula] (In formula (1), R represents a monovalent aliphatic group.)

[0025] As mentioned above, insulating materials that exhibit good dielectric properties include insulating materials containing radical polymerizable compounds and insulating materials containing active ester resins as curing agents for epoxy resins. With the recent increase in communication speeds, insulating materials for circuit boards are required to exhibit even better dielectric properties, but there was room for improvement in the dielectric properties of these conventional insulating materials. Furthermore, semiconductor devices are sometimes exposed to high-temperature environments, such as when operating in high-frequency environments, and it has been found that even materials that exhibit good dielectric properties at room temperature may experience deterioration in dielectric properties (especially dielectric loss tangent) at high temperatures, and may not achieve the desired dielectric properties in actual use environments.

[0026] In contrast, the thermosetting resin composition of the present invention, which uses an aliphatic monofunctional epoxy resin represented by formula (1) as the epoxy resin in combination with a radical polymerizable compound, can produce a cured product that exhibits a low dielectric loss tangent at room temperature and suppresses the increase in dielectric loss tangent even at high temperatures, resulting in a product with good dielectric loss tangent. Furthermore, the thermosetting resin composition of the present invention, which uses an aliphatic monofunctional epoxy resin represented by formula (1) in combination with a radical polymerizable compound, can produce a cured product that exhibits a sufficient glass transition temperature and good heat resistance, as well as a cured product that exhibits good reflow resistance.

[0027] The thermosetting resin composition of the present invention may contain other epoxy resins, as long as it contains the aliphatic monofunctional epoxy resin represented by formula (1) above. Hereinafter, the aliphatic monofunctional epoxy resin represented by formula (1) above will be simply referred to as "aliphatic monofunctional epoxy resin" or "component (A)", and other epoxy resins will be referred to as "epoxy resins other than component (A)" or simply "component (A')". Furthermore, these components (A) and (A') will be collectively referred to simply as "epoxy resin".

[0028] The following explains each component.

[0029] <(A) Aliphatic monofunctional epoxy resin represented by formula (1)> The thermosetting resin composition of the present invention comprises an aliphatic monofunctional epoxy resin represented by formula (1) as component (A).

[0030] [ka] (In formula (1), R represents a monovalent aliphatic group.)

[0031] As mentioned above, the monovalent aliphatic group represented by R is as follows, but in combination with a radical polymerizable compound, a monovalent aliphatic hydrocarbon group or a monovalent heteroatom-containing aliphatic group containing an oxygen atom as a heteroatom is preferred from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing an even better dielectric loss tangent.

[0032] In particular, the monovalent aliphatic hydrocarbon group is preferably an alkyl group which may have substituents, or an alkenyl group which may have substituents. The number of carbon atoms in the alkyl group or alkenyl group is as described above for aliphatic hydrocarbon groups, but from the viewpoint of enjoying the effects of the present invention, it is preferably 3 or more, more preferably 4 or more, 6 or more, or 8 or more, and the upper limit is preferably 20 or less, more preferably 18 or less, 16 or less, or 14 or less.

[0033] Furthermore, as a monovalent heteroatom-containing aliphatic group containing an oxygen atom as the heteroatom, (i) an alkoxy group or an alkenyloxy group, which may have substituents, is preferred, with the heteroatom (oxygen atom) bonded to the terminal carbon; and (ii) a monovalent saturated aliphatic group, which is interposed between the carbon-carbon bonds, and is divided by one or more divalent groups selected from the group consisting of -O-, -C(=O)-, and combinations thereof; or a monovalent unsaturated aliphatic group having one carbon-carbon double bond, which is divided by one or more divalent groups selected from the group consisting of -O-, -C(=O)-, and combinations thereof. Here, the monovalent saturated aliphatic group and the monovalent unsaturated aliphatic group having one carbon-carbon double bond in the latter embodiment (ii) may have substituents. In the former embodiment (i), the number of carbon atoms in the alkoxy group or alkenyloxy group is as described above for heteroatom-containing aliphatic groups, but from the viewpoint of enjoying the effects of the present invention, it is preferably 2 or more, more preferably 3 or more, 4 or more, 6 or more, or 8 or more, and the upper limit is preferably 20 or less, more preferably 18 or less, 16 or less, or 14 or less. Furthermore, in the latter embodiment (ii), for monovalent saturated aliphatic groups or monovalent unsaturated aliphatic groups having one carbon-carbon double bond, which are separated by one or more divalent groups selected from the group consisting of -O-, -C(=O)-, and combinations thereof, the number of carbon atoms and heteroatoms are as described above for heteroatom-containing aliphatic groups. However, from the viewpoint of enjoying the effects of the present invention to the fullest, the number of carbon atoms is preferably 4 or more, more preferably 5 or more, 6 or more, or 8 or more, with an upper limit of preferably 50 or less, more preferably 40 or less, 30 or less, or 20 or less. The number of heteroatoms (oxygen atoms) is preferably 20 or less, more preferably 18 or less, 16 or less, 14 or less, 12 or less, or 10 or less, even more preferably 8 or less, 6 or less, or 5 or less, with a lower limit of 1 or more.

[0034] Among these, in combination with radical polymerizable compounds, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, resulting in an even better dielectric loss tangent, the monovalent aliphatic group represented by R is preferably a monovalent saturated aliphatic group that is divided by an alkyl group which may have substituents, or by one or more divalent groups selected from the group consisting of -O-, -C(=O)-, and combinations thereof.

[0035] As described above, the substituents on the monovalent aliphatic group represented by R are as follows, but from the viewpoint of enjoying the effects of the present invention, halogen atoms, alkyl groups, alkenyl groups, alkoxy groups, or alkenyloxy groups are preferred, and fluorine atoms, alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, or alkenyloxy groups having 2 to 6 carbon atoms are more preferred.

[0036] In combination with radical polymerizable compounds, it is preferable that the monovalent aliphatic group represented by R, including substituents, does not contain an aromatic ring, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing a good dielectric loss tangent. An aromatic ring refers to a ring that exhibits aromaticity according to Hückel's rule, where the number of electrons in the π-electron system on the ring is 4p+2 (where p is a natural number).

[0037] In one preferred embodiment, R in formula (1) is represented by the following formula (2).

[0038] [ka] (In formula (2), R 1 This represents a monovalent aliphatic group, R 2 and R 3 Each of these independently represents a divalent aliphatic group. X represents -C(=O)-O-, or -O-. n1 represents a number between 0 and 50. n2 and n3 each independently represent either 0 or 1.

[0039] In formula (2), R 1 R represents a monovalent aliphatic group. 1 As previously mentioned, the monovalent aliphatic group represented by is preferable, but in combination with a radical polymerizable compound, it is preferable to use an alkyl group which may have substituents, or an alkenyl group which may have substituents, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures to obtain an even better dielectric loss tangent. The number of carbon atoms in the alkyl group or alkenyl group is as previously mentioned for the aliphatic hydrocarbon group, but from the viewpoint of enjoying the effects of the present invention, it is preferably 3 or more, more preferably 4 or more, 6 or more, or 8 or more, and the upper limit is preferably 20 or less, more preferably 18 or less, 16 or less, or 14 or less.

[0040] In formula (2), R 2 Each of these independently represents a divalent aliphatic group. 2 As previously mentioned, the divalent aliphatic group represented by is preferable, but in combination with a radical polymerizable compound, it is preferable to use an alkylene group that may have substituents or an alkenylene group that may have substituents, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing an even better dielectric loss tangent. The number of carbon atoms in the alkylene group or alkenylene group is as previously mentioned for the aliphatic hydrocarbon group, but from the viewpoint of enjoying the effects of the present invention, it is preferable to use one or more or two or more, and the upper limit is preferably six or less, four or less, or three or less.

[0041] In formula (2), R 3 R represents a divalent aliphatic group. 3As previously described, the divalent aliphatic group represented by is preferable, but in combination with a radical polymerizable compound, it is preferable to use an alkylene group which may have substituents, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing an even better dielectric loss tangent. The number of carbon atoms in the alkylene group is as previously described for the aliphatic hydrocarbon group, but from the viewpoint of enjoying the effects of the present invention, it is preferably 6 or less, 4 or less, or 3 or less, more preferably 2 or 1.

[0042] In formula (2), X represents -C(=O)-O- (carbonyloxy group; ester bond) or -O- (oxy group; ether bond).

[0043] In formula (2), n1 represents a number from 0 to 50, preferably 40 or less, more preferably 30 or less, 25 or less, 20 or less, or 15 or less. When n1 is 1 or greater, it is preferable to determine the type of R2 and the value of n1 such that the epoxy group equivalent of component (A) satisfies the preferred range described later.

[0044] In equation (2), n2 and n3 each independently represent either 0 or 1.

[0045] R 1 A monovalent aliphatic group represented by R 2 , R 3 As described above, the substituents in the divalent aliphatic group represented by are, among them, halogen atoms, alkyl groups, alkenyl groups, alkoxy groups, or alkenyloxy groups are preferred from the viewpoint of enjoying the effects of the present invention, and fluorine atoms, alkyl groups having 1 to 6 carbon atoms, alkenyl groups having 2 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, or alkenyloxy groups having 2 to 6 carbon atoms are more preferred.

[0046] Examples of monovalent aliphatic groups represented by R, i.e., monovalent aliphatic groups represented by formula (2), which are particularly suitable in combination with radical polymerizable compounds, from the viewpoint of producing cured products that exhibit a low dielectric loss tangent at room temperature and further suppress the increase in dielectric loss tangent even at high temperatures, thereby resulting in even better dielectric loss tangent, are shown below.

[0047] In one preferred embodiment, in formula (2), R 1 This represents an optionally substituted alkyl group or an optionally substituted alkenyl group. R 2 This represents an optionally substituted alkylene group or an optionally substituted alkenylene group. R 3 This represents an alkylene group which may have substituents, X represents -C(=O)-O-, or -O-. n1 represents a number between 0 and 30. n2 and n3 each independently represent 0 or 1, where the substituent is one or more selected from halogen atoms, alkyl groups, alkenyl groups, alkoxy groups, and alkenyloxy groups.

[0048] In a more preferred embodiment, in formula (2), R 1 C3-C which may have substituents 20 Alkyl groups, or C3-C groups which may have substituents. 20 Represents an alkenyl group, R 2 This represents a C2-C4 alkylene group which may have substituents, or a C2-C4 alkenylene group which may have substituents. R 3 This represents a C1-C4 alkylene group which may have substituents, X represents -C(=O)-O-, or -O-. n1 represents a number between 0 and 20. n2 and n3 each independently represent 0 or 1, where the substituent is one or more selected from a fluorine atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and an alkenyloxy group having 2 to 6 carbon atoms.

[0049] In combination with radical polymerizable compounds, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing an even better dielectric loss tangent, the epoxy group equivalent of component (A) is preferably 120 g / eq. or more, more preferably 140 g / eq. or more, 150 g / eq. or more, or 160 g / eq. or more, and its upper limit is preferably 1200 g / eq. or less, or 1000 g / eq. or less, more preferably 800 g / eq. or less, 600 g / eq. or less, 500 g / eq. or less, or 400 g / eq. or less. Note that the epoxy group equivalent is the mass of epoxy resin containing one equivalent of epoxy groups and can be measured according to JIS K7236.

[0050] (A) Component may be any aliphatic monofunctional epoxy resin as long as it has the structure represented by formula (1) above. For example, aliphatic monofunctional epoxy resins obtained by the reaction of various aliphatic alcohols or fatty acids with epihalohydrins, or aliphatic monofunctional epoxy resins obtained by partially oxidizing the carbon-carbon double bonds of various unsaturated aliphatic compounds may be used.

[0051] (A) Commercially available products may be used as component (A). Examples of such commercially available products include aliphatic monofunctional epoxy resins in which R in formula (1) is an aliphatic hydrocarbon group, such as "vikolox(registered trademark)-12", "vikolox(registered trademark)-14", and "vikolox(registered trademark)-16" (manufactured by Cargill); and aliphatic monofunctional epoxy resins in which R in formula (1) is a heteroatom-containing aliphatic group, such as "EX-121", "EX-171", and "EX-192" (manufactured by Nagase ChemteX Corporation; Denacol series), "ED-502", and "ED-502S" (manufactured by ADEKA Corporation; Adekaglycirol series), "DY-BP" (manufactured by Yokkaichi Gosei Co., Ltd.), and "FOLDI-E101" (manufactured by Nissan Chemical Corporation).

[0052] In combination with radical polymerizable compounds, from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing an even better dielectric loss tangent, the content of component (A) in the thermosetting resin composition is preferably 0.5% by mass or more, 0.6% by mass or more, or 0.8% by mass, more preferably 1% by mass or more, 1.5% by mass or more, 2% by mass or more, or 2.5% by mass or more, and even more preferably 3% by mass or more, 3.5% by mass or more, or 4% by mass or more, when the total resin components in the thermosetting resin composition are taken as 100% by mass. The upper limit of the content is preferably 20% by mass or less, more preferably 18% by mass or less, 16% by mass or less or 14% by mass or less, and even more preferably 13% by mass or less, 12% by mass or less, 11% by mass or less or 10% by mass or less, from the viewpoint of further suppressing the increase in dielectric loss tangent even in high-temperature environments and providing a cured product that exhibits an even better dielectric loss tangent, from the viewpoint of providing a cured product that exhibits good heat resistance and a cured product that exhibits good reflow resistance. Therefore, in one embodiment, the content of component (A) in the thermosetting resin composition is 0.5 to 20% by mass when the resin component in the thermosetting resin composition is taken as 100% by mass.

[0053] In the present invention, the term "resin component" in reference to a thermosetting resin composition refers to the non-volatile components constituting the thermosetting resin composition, excluding the inorganic filler (E) described later.

[0054] -Epoxy resin other than component (A)- The thermosetting resin composition of the present invention may contain an epoxy resin other than component (A) as component (A'), as long as it contains component (A) above as an epoxy resin.

[0055] Component (A') is not particularly limited in type, as long as it has one or more (preferably two or more) epoxy groups in one molecule and does not fall under component (A). Examples of component (A') include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, bisphenol AF type epoxy resin, phenol novolac type epoxy resin, tert-butyl-catechol type epoxy resin, naphthol type epoxy resin, naphthalene type epoxy resin, naphthylene ether type epoxy resin, glycidylamine type epoxy resin, glycidyl ester type epoxy resin, cresol novolac type epoxy resin, biphenyl type epoxy resin, phenol aralkyl type epoxy resin, biphenyl aralkyl type epoxy resin, fluorene skeleton type epoxy resin, dicyclopentadiene type epoxy resin, anthracene type epoxy resin, linear aliphatic epoxy resin, epoxy resin having a butadiene structure, alicyclic epoxy resin, heterocyclic epoxy resin, spiroring-containing epoxy resin, cyclohexanedimethanol type epoxy resin, trimethylol type epoxy resin, halogenated epoxy resin, and the like.

[0056] Component (A') is preferably an aromatic epoxy resin. Here, an aromatic epoxy resin means an epoxy resin that has an aromatic ring in its molecule.

[0057] Component (A') preferably has two or more epoxy groups in one molecule. When the non-volatile component of component (A') is considered to be 100% by mass, the proportion of epoxy resin having two or more epoxy groups in one molecule is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more.

[0058] Component (A') can be classified into an epoxy resin that is liquid at 20°C (hereinafter referred to as "liquid epoxy resin") and an epoxy resin that is solid at 20°C (hereinafter referred to as "solid epoxy resin"). When the thermosetting resin composition of the present invention contains component (A'), it may further contain only liquid epoxy resin, only solid epoxy resin, or a combination of liquid epoxy resin and solid epoxy resin. When a combination of liquid epoxy resin and solid epoxy resin is used as component (A'), their mass ratio (liquid epoxy resin:solid epoxy resin) is preferably 1:0.01 to 1:10, more preferably 1:0.05 to 1:5, and even more preferably 1:0.1 to 1:2.

[0059] As the liquid epoxy resin, a liquid epoxy resin having two or more epoxy groups in one molecule is preferred.

[0060] Preferred liquid epoxy resins include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AF type epoxy resin, naphthalene type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, phenol novolac type epoxy resin, alicyclic epoxy resins such as alicyclic epoxy resins having an ester skeleton, cyclohexane type epoxy resin, cyclohexanedimethanol type epoxy resin, and epoxy resins having a butadiene structure. Specific examples of liquid epoxy resins include DIC's "HP-4032," "HP-4032-D," and "HP-4032SS" (naphthalene-type epoxy resin); Mitsubishi Chemical's "828US," "jER828EL," "825," and "Epicote 828EL" (bisphenol A-type epoxy resin); Mitsubishi Chemical's "jER807" and "1750" (bisphenol F-type epoxy resin); Mitsubishi Chemical's "jER152" (phenol novolac-type epoxy resin); and Mitsubishi Chemical's "630" and "630LSD" (glycidylamine-type epoxy resin). Examples of resins include: "ZX1059" (a mixture of bisphenol A type epoxy resin and bisphenol F type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "EX-721" (glycidyl ester type epoxy resin) manufactured by Nagase ChemteX Co., Ltd.; "Celoxide 2021P" (alicyclic epoxy resin with an ester skeleton) manufactured by Daicel Corporation; "PB-3600" (epoxy resin with a butadiene structure) manufactured by Daicel Corporation; and "ZX1658" and "ZX1658GS" (liquid 1,4-glycidylcyclohexane type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.

[0061] As the solid epoxy resin, a solid epoxy resin having three or more epoxy groups per molecule is preferred, and an aromatic solid epoxy resin having three or more epoxy groups per molecule is more preferred.

[0062] Preferred solid epoxy resins include bixylenol-type epoxy resin, naphthalene-type epoxy resin, naphthalene-type tetrafunctional epoxy resin, cresol novolac-type epoxy resin, dicyclopentadiene-type epoxy resin, trisphenol-type epoxy resin, naphthol-type epoxy resin, biphenyl-type epoxy resin, naphthylene ether-type epoxy resin, anthracene-type epoxy resin, bisphenol A-type epoxy resin, bisphenol AF-type epoxy resin, and tetraphenylethane-type epoxy resin.Specific examples of solid epoxy resins include DIC's "HP-4032H" (naphthalene-type epoxy resin); DIC's "HP-4700" and "HP-4710" (naphthalene-type tetrafunctional epoxy resins); DIC's "N-690" (cresol novolac-type epoxy resin); DIC's "N-695" (cresol novolac-type epoxy resin); DIC's "HP-7200HH", "HP-7200H", and "HP-7200" (dicyclopentadie epoxy resin). (Naphthylene ether type epoxy resin); DIC Corporation's "EXA-7311", "EXA-7311-G3", "EXA-7311-G4", "EXA-7311-G4S", "HP6000" (naphthylene ether type epoxy resin); Nippon Kayaku Co., Ltd.'s "EPPN-502H" (trisphenol type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC-7000L" (naphthol novolac type epoxy resin); Nippon Kayaku Co., Ltd.'s "NC-3000H", "NC-3000", "NC-3000 "L", "NC-3100" (biphenyl type epoxy resin); "ESN-475V" (naphthol type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "ESN-485" (naphthol novolac type epoxy resin) manufactured by Nippon Steel Chemical & Material Co., Ltd.; "YX4000H", "YX4000", "YL6121" (biphenyl type epoxy resin) manufactured by Mitsubishi Chemical Corporation; "YX4000HK" (bixylenol type epoxy resin) manufactured by Mitsubishi Chemical Corporation; manufactured by Mitsubishi Chemical Corporation Examples include "YX8800" (anthracene-type epoxy resin); "PG-100" and "CG-500" from Osaka Gas Chemical Co., Ltd.; "YL7760" (bisphenol AF-type epoxy resin) from Mitsubishi Chemical Corporation; "YL7800" (fluorene-type epoxy resin) from Mitsubishi Chemical Corporation; "jER1010" (solid bisphenol A-type epoxy resin) from Mitsubishi Chemical Corporation; and "jER1031S" (tetraphenylethane-type epoxy resin) from Mitsubishi Chemical Corporation.

[0063] The epoxy group equivalent of component (A') is preferably 50 g / eq. to 2000 g / eq., more preferably 60 g / eq. to 1000 g / eq., and even more preferably 80 g / eq. to 500 g / eq.

[0064] The weight-average molecular weight (Mw) of component (A') is preferably 100 to 5,000, more preferably 250 to 3,000, and even more preferably 400 to 1,500. The Mw of the epoxy resin can be measured as a polystyrene equivalent value by the GPC method.

[0065] When the thermosetting resin composition of the present invention contains component (A'), i.e., epoxy resin other than component (A), the content of component (A) is preferably 1% by mass or more, 2% by mass or more, or 3% by mass or more, more preferably 5% by mass or more, 6% by mass or more, or 8% by mass or more, and even more preferably 9% by mass or more, or 10% by mass or more. The upper limit of the content of component (A) in the total epoxy resin is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, 28% by mass or less, 26% by mass or less, or 25% by mass or less, from the viewpoint of further suppressing the increase in dielectric loss tangent even in high-temperature environments and providing a cured product that exhibits an even better dielectric loss tangent, from the viewpoint of providing a cured product that exhibits good heat resistance, and from the viewpoint of providing a cured product with good reflow resistance.

[0066] In the thermosetting resin composition of the present invention, the total content of epoxy resin, i.e., the total content of component (A) and component (A'), may be appropriately determined to satisfy the preferred range of the content of component (A) and the content of component (A) in the total epoxy resin. For example, the total content of epoxy resin in the thermosetting resin composition is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, 25% by mass or more, 26% by mass or more, 28% by mass or more, or 30% by mass or more, when the resin components in the thermosetting resin composition are taken as 100% by mass. The upper limit of this content is not particularly limited and may be determined according to the properties required of the thermosetting resin composition, but from the viewpoint of enjoying the effects of the present invention more in combination with a radical polymerizable compound, it is preferably 60% by mass or less, 55% by mass or less, or 50% by mass or less.

[0067] <(B) Radical polymerizable compounds> The thermosetting resin composition of the present invention contains a radical polymerizable compound as component (B). This makes it possible to realize a thermosetting resin composition that yields a cured product exhibiting good dielectric properties.

[0068] Component (B) contains a radical polymerizable unsaturated group. This radical polymerizable unsaturated group represents a group containing an unsaturated bond that exhibits radical polymerizability. Examples of such radical polymerizable unsaturated groups include groups containing an ethylenic double bond.

[0069] Examples of radically polymerizable unsaturated groups include vinyl groups, allyl groups, vinylphenyl groups, acryloyl groups, methacryloyl groups, fumaroyl groups, and maleoyl groups. The number of radically polymerizable unsaturated groups contained in component (B) is usually one or more, preferably two or more. If component (B) contains two or more radically polymerizable unsaturated groups, these two or more radically polymerizable unsaturated groups may be the same or different.

[0070] From the viewpoint of obtaining a cured product exhibiting even better dielectric properties, component (B) preferably contains an aromatic ring together with a radically polymerizable unsaturated group. Therefore, in a preferred embodiment, component (B) is a compound containing a radically polymerizable unsaturated group and an aromatic ring.

[0071] (B) If component contains an aromatic ring, the aromatic ring may be an aromatic carbocyclic ring or an aromatic heterocyclic ring. The aromatic ring may also be a monocyclic aromatic ring, a fused aromatic ring formed by the fusion of two or more monocyclic aromatic rings, or a fused aromatic ring formed by the fusion of one or more monocyclic aromatic rings with one or more monocyclic non-aromatic rings. Examples of these aromatic rings include monocyclic aromatic rings such as benzene rings and pyridine rings; and fused aromatic rings such as indan rings, fluorene rings, and naphthalene rings. Among these, aromatic carbocyclic rings are preferred. The number of carbon atoms in the aromatic carbocyclic ring is preferably 6 to 10.

[0072] If component (B) contains an aromatic ring, the aromatic ring may have substituents. Such substituents are as described above, but in combination with component (A), from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, resulting in an even better dielectric loss tangent, it is preferable to have one or more substituents selected from the group consisting of halogen atoms, alkyl groups, alkyloxy groups, alkylthio groups, cycloalkyl groups, aryl groups, aryloxy groups, arylthio groups, hydroxyl groups, and mercapto groups. The number of substituents bonded to one aromatic ring may be one or two or more. If the number of substituents is two or more, these two or more substituents may be the same or different. In particular, it is preferable that the aromatic ring contained in component (B) has no substituents bonded to it or has an alkyl group bonded to it.

[0073] (B) If component contains aromatic rings, the number of aromatic rings is usually one or more, preferably two or more. (B) If component contains two or more aromatic rings, these two or more aromatic rings may be the same or different.

[0074] Suitable examples of component (B), which contains two or more radical polymerizable unsaturated groups and two or more aromatic rings, include the compounds described later, as well as, for example, "NE-V-1100-70T" manufactured by DIC Corporation (a compound containing multiple allyl groups and multiple benzene rings).

[0075] In particular, component (B) preferably contains a group represented by the following formula (B1).

[0076] [ka]

[0077] (In equation (B1), R A1 , R A2 and R A3 Each of these independently represents a hydrogen atom or an alkyl group; R A4 Each of these independently represents an alkyl group; m a1 represents 0 or 1; m a2represents an integer between 0 and 4; * represents a combination.

[0078] In equation (B1), R A1 , R A2 and R A3 Each of these independently represents a hydrogen atom or an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 18, more preferably 1 to 12, even more preferably 1 to 6, and even more preferably 1 to 2. The alkyl group may be linear, branched, or cyclic. Examples of alkyl groups include methyl, ethyl, propyl, n-butyl, and t-butyl groups. Among these, R A1 The hydrogen atom or methyl group is preferred, R A2 and R A3 A hydrogen atom is preferred.

[0079] In equation (B1), R A4 Each of these independently represents an alkyl group. The number of carbon atoms in the alkyl group is preferably 1 to 12, more preferably 1 to 6, and even more preferably 1 to 2. The alkyl group may be linear, branched, or cyclic. Examples of alkyl groups include methyl, ethyl, propyl, n-butyl, and t-butyl groups. Among these, R A1 A methyl group is preferred.

[0080] In equation (B1), m a1 This represents 0 or 1. A1 If m is a hydrogen atom, a1 0 is preferable. Also, R A1 If m is an alkyl group, a1 1 is preferable.

[0081] In equation (B1), m a2 m represents an integer between 0 and 4. a2 It is preferably 0 to 2.

[0082] Component (B) may contain one group represented by formula (B1) per molecule, but it is preferable that it contains two or more.

[0083] As component (B), compounds containing a polyphenylene ether skeleton are preferred. Examples of components (B) containing a polyphenylene ether skeleton include compounds represented by the following formula (B2).

[0084] [ka]

[0085] (In formula (B2), L 1 R represents a divalent linking group; B11 , R B12 , R B13 , R B21 , R B22 and R B23 Each of these independently represents a hydrogen atom or an alkyl group; R B14 , R B15 , R B24 and R B25 Each of these independently represents an alkyl group; R B16 and R B26 Each of these independently represents an alkylene group; m b11 and m b21 Each represents either 0 or 1 independently; m b12 , m b13 , m b22 and m b23 Each of these independently represents an integer from 0 to 4; m b14 and m b24 Each of these independently represents an integer between 0 and 300; m b15 and m b25 Each of these independently represents either 0 or 1.

[0086] In equation (B2), L 1 - represents a divalent linking group. Examples of divalent linking groups include alkylene groups, alkenylene groups, arylene groups, alkylarylene groups, heteroarylene groups, -O-, -NH-, and -NR. x Examples include -, -CO-, -CS-, -SO-, -SO2-, -C(=O)O-, -NHC(=O)-, -NC(=O)N-, -NHC(=O)O-, -C(=O)-, -S-, and combinations of these groups.x represents a hydrocarbyl group having 1 to 12 carbon atoms. L 1 has a carbon atom number of usually 60 or less, more preferably 48 or less, still more preferably 36 or less, and even more preferably 24 or less.

[0087] In formula (B2), R B11 , R B12 , R B13 , R B21 , R B22 and R B23 each independently represent a hydrogen atom or an alkyl group. R B11 , R B12 , R B13 , R B21 , R B22 and R B23 can be the same as R A1 , R A2 and R A3 in formula (B1). Among them, R B11 and R B21 are preferably a hydrogen atom or a methyl group, and R B12 , R B13 , R B22 and R B23 are preferably a hydrogen atom.

[0088] In formula (B2), R B14 , R B15 , R B24 and R B25 each independently represent an alkyl group. R B14 , R B15 , R B24 and R B25 can be the same as R A4 in formula (B1). Among them, R B14 , R B15 , R B24 and R B25 are preferably a methyl group.

[0089] In formula (B2), R B16 and R B26Each of these independently represents an alkylene group. The number of carbon atoms in the alkylene group is preferably 1 to 10, more preferably 1 to 6, and even more preferably 1 to 3. A linear alkylene group is preferred, and a methylene group is more preferred.

[0090] In equation (B2), m b11 and m b21 Each of these independently represents either 0 or 1.

[0091] In equation (B2), m b12 , m b13 , m b22 and m b23 Each of these independently represents an integer from 0 to 4. b12 , m b13 , m b22 and m b23 The number is preferably 1 to 4, more preferably 2 to 3, and particularly preferably 2.

[0092] In equation (B2), m b14 and m b24 Each of these independently represents an integer between 0 and 300. For details, see m b14 and m b24 It is usually 0 or greater, preferably 1 or greater, usually 300 or less, preferably 100 or less, more preferably 50 or less, even more preferably 20 or less, and even more preferably 10 or less.

[0093] In equation (B2), m b15 and m b25 Each of these independently represents either 0 or 1. b11 If m is 0, b15 It is preferably 1, m b11 If m is 1, b15 It is preferably 0. Also, m b21 If m is 0, b25 It is preferably 1, m b21 If m is 1, b25 It is preferably 0.

[0094] A preferred example of a compound represented by formula (B2) is the compound represented by the following formula (B3).

[0095] [ka]

[0096] (In formula (B3), L 2 R represents a divalent linking group; C15 and R C25 Each of these independently represents an alkyl group; R C16 and R C26 Each of these independently represents an alkylene group; m c14 and m c24 Each of these independently represents an integer between 0 and 300.

[0097] In equation (B3), L 2 This represents a divalent linking group. 2 L in equation (B2) 1 It could be the same as L 2 A divalent group represented by the following formula (B3-1) is preferred.

[0098] [ka]

[0099] (In equation (B3-1), X F1 ~X F8 Each of these independently represents a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or a phenyl group. * represents a bond.

[0100] In equation (B3), R C15 and R C25 Each of these independently represents an alkyl group. C15 and R C25 R in equation (B1) A4 It could be the same as R. C15 and R C25 A methyl group is preferred.

[0101] In equation (B3), R C16 and R C26 Each of these independently represents an alkylene group. C16 and R C26 This is R in equation (B2). B16 and R B26 It could be the same as R. C16 and R C26 A methylene group is more preferable.

[0102] In equation (B3), m c14 and m c24 Each of these independently represents an integer between 0 and 300. c14 and m c24 This is the m in equation (B2). b14 and m b24 It can be the same as. Also, in formula (B3), preferably, m c14 and m c24 Configurations where one of the values ​​is 0 are excluded.

[0103] Examples of compounds represented by formula (B3) include those represented by the following formula (B4). In formula (B4), m c14 and m c24 This represents the same number as in formula (B3). The compound represented by formula (B4) is available as "OPE-2St" manufactured by Mitsubishi Gas Chemical Company.

[0104] [ka]

[0105] Another preferred example of a compound represented by formula (B2) is the compound represented by the following formula (B5).

[0106] [ka]

[0107] (In formula (B5), L 3 R represents a divalent linking group; D11 and RD21 Each of these independently represents a hydrogen atom or an alkyl group; R D14 , R D15 , R D24 and R D25 Each of these independently represents an alkyl group; m d14 and m d24 Each of these independently represents an integer between 0 and 300.

[0108] In formula (B5), L 3 This represents a divalent linking group. 3 L in equation (B2) 1 It could be the same as L 3 These are alkylene groups, alkenylene groups, -O-, -NR x It is preferably one selected from the group consisting of -, -CO-, -CS-, -SO-, and -SO2-, an alkylene group is preferred, and an isopropylidene group (-C(CH3)2-) is particularly preferred.

[0109] In equation (B5), R D11 and R D21 Each of these independently represents either a hydrogen atom or an alkyl group. D11 and R D21 This is R in equation (B2). B11 and R B21 It could be the same as R. D11 and R D21 A methyl group is preferred.

[0110] In equation (B5), R D14 , R D15 , R D24 and R D25 Each of these independently represents an alkyl group. D14 , R D15 , R D24 and R D25 R in equation (B1) A4 It could be the same as R. D14 , R D15 , R D24 and R D25 A methyl group is preferred.

[0111] In equation (B5), m d14 and m d24 Each of these independently represents an integer between 0 and 300. d14 and m d24 This is the m in equation (B2). b14 and m b24 It can be the same as m b14 and m b24 The sum of these values ​​is preferably 2 or more.

[0112] Examples of compounds represented by formula (B5) include the compound represented by the following formula (B6). In formula (B6), L 3 , m d14 and m d24 This is the same as formula (B5). The compound represented by formula (B4) is available as "NORYL SA9000" manufactured by SABIC.

[0113] [ka]

[0114] Another preferred example of component (B) is a polymer containing a structural unit represented by the following formula (B7).

[0115] [ka]

[0116] (In equation (B7), R E1 , R E2 and R E3 Each of these independently represents a hydrogen atom or an alkyl group; R E4 Each of these independently represents an alkyl group; R E5 , R E6 and R E7 Each of these independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; m e1 represents 0 or 1; m e2 represents an integer between 0 and 4; * represents a combination.

[0117] In equation (B7), R E1 , R E2 and R E3 Each of these independently represents either a hydrogen atom or an alkyl group. E1 , R E2 and R E3 R in equation (B1) A1 , R A2 and R A3 It could be the same as R. E1 , R E2 and R E3 A hydrogen atom is preferred.

[0118] In equation (B7), R E4 Each of these independently represents an alkyl group. E4 R in equation (B1) A4 It could be the same as that.

[0119] In equation (B7), R E5 , R E6 and R E7 Each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. Among them, R E5 , R E6 and R E7 A hydrogen atom is preferred.

[0120] In equation (B7), m e1 This represents 0 or 1, preferably 0.

[0121] In equation (B7), m e2 This represents an integer between 0 and 4, preferably 0.

[0122] The molar content of the structural unit represented by formula (B7) in a polymer containing the structural unit represented by formula (B7) is preferably within a specific range, relative to 100 mol% of the total structural units. Specifically, the molar content of the structural unit represented by formula (B7) is preferably 2 mol% to 95 mol%, and more preferably 8 mol% to 81 mol%. Furthermore, the average number of structural units represented by formula (B7) contained in one molecule of the polymer is preferably 1 to 160, and more preferably 3 to 140.

[0123] A polymer containing the structural unit represented by formula (B7) may also contain any other structural unit in combination with the structural unit represented by formula (B7). Examples of such arbitrary structural units include the structural unit represented by the following formula (B7-1).

[0124] [ka]

[0125] (In equation (B7-1), R E8 , R E9 and R E10 Each of these independently represents either a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. E1 Ar represents an aryl group which may have substituents. E1 Possible substituents include alkyl groups having 1 to 6 carbon atoms. (* represents a bond.)

[0126] Polymers containing the structural unit represented by formula (B7) include, for example, copolymers containing a combination of the structural unit represented by formula (B8), the structural unit represented by formula (B8-1), and the structural unit represented by formula (B8-2). In formulas (B8), (B8-1), and (B8-2), * represents a bond. In this copolymer, the molar content of the structural unit represented by formula (B8), the structural unit represented by formula (B8-1), and the structural unit represented by formula (B8-2) is 8 mol% to 54 mol%, 0 mol% to 92 mol%, and 0 mol% to 89 mol%, respectively. Furthermore, the average number of the structural units represented by formula (B8), the structural unit represented by formula (B8-1), and the structural unit represented by formula (B8-2) contained in one molecule of this copolymer is 1 to 160, 0 to 350, and 0 to 270, respectively. This copolymer is available from Nippon Steel Chemical & Material Co., Ltd. as "ODV-XET(X03)", "ODV-XET(X04)", and "ODV-XET(X05)".

[0127] [ka]

[0128] (B) Component may be used alone, or two or more components may be used in any ratio.

[0129] The radical polymerizable unsaturated group equivalent of component (B) is preferably 250 g / eq. to 1200 g / eq., more preferably 300 g / eq. to 1100 g / eq. The radical polymerizable unsaturated group equivalent represents the mass of component (B) per equivalent of radical polymerizable unsaturated groups. When the radical polymerizable unsaturated group equivalent of component (B) is within the above range, the effects of the present invention can be significantly obtained in combination with component (A).

[0130] The Mw of component (B) is preferably 1,000 to 40,000, more preferably 1,500 to 35,000. The Mw of component (B) can be measured as a polystyrene equivalent value by the GPC method.

[0131] In combination with an aliphatic monofunctional epoxy resin (component (A)), from the viewpoint of obtaining a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing an even better dielectric loss tangent, the content of component (B) in the thermosetting resin composition is preferably 1% by mass or more, 2% by mass or more, or 4% by mass or more, more preferably 5% by mass or more, 6% by mass or more, or 8% by mass or more, and even more preferably 10% by mass or more, 15% by mass or more, or 20% by mass or more, when the resin components in the thermosetting resin composition are taken as 100% by mass, with an upper limit preferably 70% by mass or less, more preferably 65% ​​by mass or less, and even more preferably 60% by mass or less, or 55% by mass or less. Therefore, in one embodiment, the content of component (B) in the thermosetting resin composition is 1 to 70% by mass when the resin components in the thermosetting resin composition are taken as 100% by mass.

[0132] From the viewpoint of providing a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, thereby providing a cured product that exhibits good heat resistance and reflow resistance, the mass ratio of component (A) to component (B) ((A) / (B)) is preferably 0.01 or more, more preferably 0.02 or more, 0.04 or more, 0.05 or more, 0.06 or more, or 0.08 or more, even more preferably 0.1 or more, 0.12 or more, 0.14 or more, or 0.15 or more, and its upper limit is preferably 5 or less, 4 or less, or 2 or less, more preferably 1.5 or less, 1.4 or less, or 1.2 or less, even more preferably 1.1 or less, 1 or less, 0.95 or less, 0.9 or less, 0.8 or less, 0.7 or less, 0.6 or less, or 0.5 or less.

[0133] <(C) Hardener> The thermosetting resin composition of the present invention may further contain a curing agent as component (C). The curing agent is not particularly limited as long as it has the function of curing epoxy resin, and examples include phenolic curing agents, naphthol curing agents, active ester curing agents, acid anhydride curing agents, benzoxazine curing agents, cyanate ester curing agents, carbodiimide curing agents, and amine curing agents. The curing agent may be used alone or in combination of two or more.

[0134] From the viewpoint of heat resistance and water resistance, phenolic curing agents having a novolac structure or naphthol curing agents having a novolac structure are preferred as phenolic curing agents and naphthol curing agents. Furthermore, from the viewpoint of achieving an insulating layer with good adhesion strength (peel strength) to the conductive layer, nitrogen-containing phenolic curing agents or nitrogen-containing naphthol curing agents are preferred, and triazine skeleton-containing phenolic curing agents or triazine skeleton-containing naphthol curing agents are more preferred. Among these, from the viewpoint of highly satisfying heat resistance, water resistance, and adhesion strength to the conductive layer, triazine skeleton-containing phenol novolac resin or triazine skeleton-containing naphthol novolac resin is preferred.

[0135] Specific examples of phenol-based and naphthol-based curing agents include, for example, "MEH-7700," "MEH-7810," "MEH-7851," and "MEH-8000H" from Meiwa Kasei Co., Ltd.; "NHN," "CBN," and "GPH" from Nippon Kayaku Co., Ltd.; and "SN-170," "SN-180," "SN-190," "SN-475," "SN-485," "SN-495," "SN-495V," and "SN-37" from Nippon Steel Chemical & Material Co., Ltd. Examples include "5", "SN-395", "TD-2090", "TD-2090-60M", "LA-7052", "LA-7054", "LA-1356", "LA-3018", "LA-3018-50P", "EXB-9500", "HPC-9500", "KA-1160", "KA-1163", "KA-1165" from DIC Corporation, and "GDP-6115L", "GDP-6115H", "ELPC75" from Gun-ei Chemical Co., Ltd.

[0136] As the active ester curing agent, a compound having one or more active ester groups in one molecule can be used. Among these, compounds having two or more highly reactive ester groups in one molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds, are preferred as the active ester curing agent. The active ester curing agent is preferably obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. In particular, from the viewpoint of improving heat resistance, an active ester curing agent derived from a carboxylic acid compound is preferred, an active ester curing agent obtained from a carboxylic acid compound and a hydroxy compound is more preferred, and an active ester curing agent obtained from a carboxylic acid compound and an aromatic hydroxy compound is even more preferred.

[0137] As the carboxylic acid compound, either an aromatic carboxylic acid compound or an aliphatic carboxylic acid may be used, for example, benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, etc.

[0138] Examples of aromatic hydroxy compounds include (i) polyaddition products of unsaturated aliphatic cyclic compounds containing two double bonds in one molecule and phenols, (ii) various bisphenol compounds, (iii) aromatic polyols in which two or more hydroxyl groups are bonded to a carbon atom on an aromatic ring, and (iv) aromatic monools in which one hydroxyl group is bonded to a carbon atom on an aromatic ring. Examples of polyaddition products of unsaturated aliphatic cyclic compounds and phenols include polyaddition products of unsaturated aliphatic cyclic compounds such as dicyclopentadiene, tetrahydroindene, norbornadiene, limonene, and vinylcyclohexene with phenols that may have substituents (e.g., phenol, cresol, xylenol, ethylphenol, propylphenol, vinylphenol, allylphenol, phenylphenol, benzylphenol, halophenol, etc.), and specifically, for example, dicyclopentadiene-phenol polyadditions. Examples of bisphenol compounds include bisphenol A, bisphenol F, bisphenol AF, bisphenol AP, bisphenol B, bisphenol BP, bisphenol C, and bisphenol M. Examples of aromatic polyols, in which two or more hydroxyl groups are bonded to a carbon atom on an aromatic ring, include hydroquinone, resorcinol, catechol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and phenol novolac. Examples of aromatic monools, in which one hydroxyl group is bonded to a carbon atom on an aromatic ring, include phenol, cresol, xylenol, ethylphenol, propylphenol, vinylphenol, allylphenol, phenylphenol, benzylphenol, halophenol, naphthol, methylnaphthol, dimethylnaphthol, ethylnaphthol, propylnaphthol, vinylnaphthol, allylnaphthol, phenylnaphthol, benzylnaphthol, and halonaphthol.

[0139] Suitable examples of active ester-based curing agents include active ester compounds containing a dicyclopentadiene-type diphenol structure, active ester compounds containing a naphthalene structure, active ester compounds containing an acetylated phenol novolac, and active ester compounds containing a benzoylated phenol novolac. Among these, active ester compounds containing a naphthalene structure and active ester compounds containing a dicyclopentadiene-type diphenol structure are more preferred. "Dicyclopentadiene-type diphenol structure" refers to a divalent structural unit consisting of phenylene-dicyclopentalene-phenylene.

[0140] Commercially available active ester curing agents include, as active ester resins containing a dicyclopentadiene-type diphenol structure, "EXB-9451", "EXB-9460", "EXB-9460S", "HPC-8000-65T", "HPC-8000H-65TM", and "HPC-8000L-65TM" (manufactured by DIC Corporation); and as active ester resins containing a naphthalene structure, "EXB-8100L-65T", "EXB-8150-60T", "EXB-8150-62T", "EXB-9416-70BK", "HPC-8150-60T", and "HPC-8150-62T". Examples include "HP-B-8151-62T" and "HP-C-8151-62T" (manufactured by DIC Corporation); "EXB9401" (manufactured by DIC Corporation) as a phosphorus-containing active ester resin; "DC808" (manufactured by Mitsubishi Chemical Corporation) as an active ester resin that is an acetylated phenol novolac; "YLH1026," "YLH1030," and "YLH1048" (manufactured by Mitsubishi Chemical Corporation) as active ester resins that are benzoylated phenol novolacs; and "PC1300-02-65MA" (manufactured by Air Water Corporation) as an active ester resin containing a styryl group and a naphthalene structure.

[0141] Examples of acid anhydride-based curing agents include curing agents having one or more acid anhydride groups in one molecule. Specific examples of acid anhydride-based curing agents include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylhexahydrophthalic anhydride, methylnadic anhydride, hydrogenated methylnadic anhydride, trialkyltetrahydrophthalic anhydride, dodecenyl succinic anhydride, 5-(2,5-dioxotetrahydro-3-furanyl)-3-methyl-3-cyclohexen-1,2-dicarboxylic acid anhydride, trimellitic anhydride, pyromellitic anhydride, and benzophenone tetracarboxylic acid di Examples of acid anhydrides include anhydrides, biphenyltetracarboxylic acid dianhydride, naphthalenetetracarboxylic acid dianhydride, oxydiphthalic acid dianhydride, 3,3'-4,4'-diphenylsulfonetetracarboxylic acid dianhydride, 1,3,3a,4,5,9b-hexahydro-5-(tetrahydro-2,5-dioxo-3-furanyl)-naphtho[1,2-C]furan-1,3-dione, ethylene glycol bis(anhydrotrimellitate), and polymer-type acid anhydrides such as styrene-maleic acid resin copolymerized with styrene and maleic acid. A commercially available acid anhydride-based curing agent is "MH-700" manufactured by Shin Nippon Rika Co., Ltd.

[0142] Specific examples of benzoxazine-based curing agents include "JBZ-OD100" (benzoxazine ring equivalent 218), "JBZ-OP100D" (benzoxazine ring equivalent 218), and "ODA-BOZ" (benzoxazine ring equivalent 218) manufactured by JFE Chemical Corporation; "Pd" (benzoxazine ring equivalent 217) and "Fa" (benzoxazine ring equivalent 217) manufactured by Shikoku Chemicals Co., Ltd.; and "HFB2006M" (benzoxazine ring equivalent 432) manufactured by Showa Polymer Co., Ltd.

[0143] Examples of cyanate ester curing agents include bifunctional cyanate resins such as bisphenol A dicyanate, polyphenol cyanate, oligo(3-methylene-1,5-phenylene cyanate), 4,4'-methylenebis(2,6-dimethylphenyl cyanate), 4,4'-ethylidene diphenyl dicyanate, hexafluorobisphenol A dicyanate, 2,2-bis(4-cyanate)phenylpropane, 1,1-bis(4-cyanatephenylmethane), bis(4-cyanate-3,5-dimethylphenyl)methane, 1,3-bis(4-cyanatephenyl-1-(methylethylidene))benzene, bis(4-cyanatephenyl) thioether, and bis(4-cyanatephenyl) ether; polyfunctional cyanate resins derived from phenol novolacs and cresol novolacs, etc.; and prepolymers in which these cyanate resins are partially triazined. Specific examples of cyanate ester-based curing agents include "PT30" and "PT60" (phenol novolac type polyfunctional cyanate ester resin), "ULL-950S" (polyfunctional cyanate ester resin), "BA230", and "BA230S75" (prepolymers in which part or all of bisphenol A dicyanate is triazined and trimerized), all manufactured by Lonza Japan.

[0144] Specific examples of carbodiimide-based curing agents include Carbodilite® V-03 (carbodiimide group equivalent: 216 g / eq.), V-05 (carbodiimide group equivalent: 262 g / eq.), V-07 (carbodiimide group equivalent: 200 g / eq.), V-09 (carbodiimide group equivalent: 200 g / eq.) manufactured by Nisshinbo Chemical Corporation, and Stavaxol® P (carbodiimide group equivalent: 302 g / eq.) manufactured by Rhein Chemie.

[0145] Examples of amine-based curing agents include curing agents having one or more amino groups in one molecule, such as aliphatic amines, polyetheramines, alicyclic amines, and aromatic amines. Specific examples of amine-based curing agents include 4,4'-methylenebis(2,6-dimethylaniline), diphenyldiaminosulfone, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, m-phenylenediamine, m-xylylenediamine, diethyltoluenediamine, 4,4'-diaminodiphenyl ether, 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dihydroxybenzidine, and 2,2-bis(3-amino-4-hydroxy Examples include bis(4-(4-aminophenoxy)phenyl)propane, 3,3-dimethyl-5,5-diethyl-4,4-diphenylmethanediamine, 2,2-bis(4-(4-aminophenoxy)phenyl)propane, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis(4-(4-aminophenoxy)phenyl)sulfone, bis(4-(3-aminophenoxy)phenyl)sulfone, etc. Commercial amine-based curing agents may also be used, such as "KAYABOND C-200S", "KAYABOND C-100", "KAYAHARD AA", "KAYAHARD AB", and "KAYAHARD AS" from Nippon Kayaku Co., Ltd., and "Epicure W" from Mitsubishi Chemical Corporation.

[0146] As mentioned above, from the viewpoint of achieving good dielectric properties, it is preferable that component (C) contains an active ester-based curing agent. When component (C) contains an active ester-based curing agent, the content of the active ester-based curing agent is preferably 30% by mass or more, more preferably 50% by mass or more, or 60% by mass or more, when the non-volatile components in the curing agent are taken as 100% by mass.

[0147] When the thermosetting resin composition contains component (C), the content of component (C) is preferably 1% by mass or more, 2% by mass or more, or 3% by mass or more, and more preferably 4% by mass or more, or 5% by mass or more, when the total resin components in the thermosetting resin composition are considered as 100% by mass. The upper limit of the content of component (C) is preferably 70% by mass or less, more preferably 65% ​​by mass or less, 60% by mass or less, 55% by mass or less, 50% by mass or less, 45% by mass or less, or 40% by mass or less.

[0148] <(D) Thermoplastic resin> The thermosetting resin composition of the present invention may further contain a thermoplastic resin as component (D).

[0149] Examples of thermoplastic resins include phenoxy resin, polyvinyl acetal resin, polyimide resin, polyamide-imide resin, polyetherimide resin, polysulfone resin, polyethersulfone resin, polyetheretherketone resin, polyolefin resin, polystyrene resin, and polyester resin. Thermoplastic resins may be used individually or in combination of two or more types.

[0150] The weight-average molecular weight (Mw) of the thermoplastic resin in terms of polystyrene is preferably 8,000 or more, more preferably 10,000 or more, and even more preferably 20,000 or more or 30,000 or more. The upper limit is preferably 100,000 or less, more preferably 70,000 or less, and even more preferably 60,000 or less. The Mw of the thermoplastic resin in terms of polystyrene is measured by the GPC method. Specifically, the Mw of the thermoplastic resin in terms of polystyrene can be calculated using a Shimadzu LC-9A / RID-6A measuring device, a Showa Denko Shodex K-800P / K-804L / K-804L column, and chloroform or the like as the mobile phase, with the column temperature measured at 40°C, and using a calibration curve for standard polystyrene.

[0151] Examples of phenoxy resins include phenoxy resins having one or more skeletons selected from the group consisting of bisphenol A skeleton, bisphenol F skeleton, bisphenol S skeleton, bisphenolacetophenone skeleton, novolac skeleton, biphenyl skeleton, fluorene skeleton, dicyclopentadiene skeleton, norbornene skeleton, naphthalene skeleton, anthracene skeleton, adamantane skeleton, terpene skeleton, and trimethylcyclohexane skeleton. The ends of the phenoxy resin may be any functional group such as a phenolic hydroxyl group or an epoxy group. Phenoxy resins may be used alone or in combination of two or more types. Specific examples of phenoxy resins include "1256" and "4250" (both phenoxy resins containing a bisphenol A skeleton), "YX8100" (phenoxy resin containing a bisphenol S skeleton), and "YX6954" (phenoxy resin containing a bisphenol acetophenone skeleton), all manufactured by Mitsubishi Chemical Corporation. Other examples include "FX280" and "FX293" from Nippon Steel Chemical & Material Corporation, and "YL7800BH40", "YL7500BH30", "YX6954BH30", "YX7553", "YX7553BH30", "YL7769BH30", "YL6794", "YL7213", "YL7290", and "YL7482" from Mitsubishi Chemical Corporation.

[0152] Examples of polyvinyl acetal resins include polyvinyl formal resin and polyvinyl butyral resin, with polyvinyl butyral resin being preferred. Specific examples of polyvinyl acetal resins include, for example, Denka's "Denka Butyral 4000-2," "Denka Butyral 5000-A," "Denka Butyral 6000-C," and "Denka Butyral 6000-EP," and Sekisui Chemical's Esrec BH series, BX series (e.g., BX-5Z), KS series (e.g., KS-1), BL series, and BM series.

[0153] As the polyimide resin, a resin having an imide structure (preferably a cyclic imide structure) can be used. For example, an imidized product of an acid anhydride and a diamine compound or diisocyanate compound may be used. Specific examples of polyimide resins include "Ricacoat SN20" and "Ricacoat PN20" manufactured by Shin Nippon Rika Co., Ltd. Other specific examples of polyimide resins include linear polyimides obtained by reacting a bifunctional hydroxyl-terminated polybutadiene, a diisocyanate compound, and a tetrabasic acid anhydride (polyimides described in Japanese Patent Publication No. 2006-37083), and modified polyimides containing a polysiloxane skeleton (polyimides described in Japanese Patent Publication No. 2002-12667 and Japanese Patent Publication No. 2000-319386, etc.).

[0154] Specific examples of polyamide-imide resins include "Viromax HR11NN" and "Viromax HR16NN" manufactured by Toyobo Co., Ltd. Other specific examples of polyamide-imide resins include modified polyamide-imides such as "KS9100" and "KS9300" (polysiloxane skeleton-containing polyamide-imide) manufactured by Hitachi Chemical Co., Ltd.

[0155] Specific examples of polyethersulfone resins include "PES5003P" manufactured by Sumitomo Chemical Co., Ltd. Specific examples of polyphenylene ether resins include "OPE-2St 1200," an oligophenylene ether-styrene resin manufactured by Mitsubishi Gas Chemical Company. Specific examples of polyetheretherketone resins include "Sumiproi K" manufactured by Sumitomo Chemical Co., Ltd. Specific examples of polyetherimide resins include "Ultem" manufactured by GE.

[0156] Specific examples of polysulfone resins include Solvay Advanced Polymers' polysulfones "P1700" and "P3500".

[0157] Examples of polyolefin resins include ethylene-based copolymer resins such as low-density polyethylene, ultra-low density polyethylene, high-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer; polyolefin elastomers such as polypropylene, ethylene-propylene block copolymer, etc.

[0158] Examples of polystyrene resins include, for example, homopolymers of styrene, copolymers of styrene and diene compounds (such as butadiene, isoprene, etc.) and hydrogenated products thereof. Specific examples of polystyrene resins include hydrogenated styrene-based thermoplastic resins "H1041", "Taftec H1043", "Taftec P2000", "Taftec MP10" (manufactured by Asahi Kasei Corporation); epoxidized styrene-butadiene thermoplastic resins "Epofrend AT501", "CT310" (manufactured by Daicel Corporation); modified polystyrene resins having a hydroxyl group "Septone HG252" (manufactured by Kuraray Co., Ltd.); modified polystyrene resins having a carboxyl group "Taftec N503M", modified polystyrene resins having an amino group "Taftec N501", modified polystyrene resins having an acid anhydride group "Taftec M1913" (manufactured by Asahi Kasei Chemicals Corporation); unmodified polystyrene resin "Septone S8104" (manufactured by Kuraray Co., Ltd.); styrene-ethylene / butylene-styrene block copolymers "FG1924" (manufactured by Kraton Corporation), "EF-40" (manufactured by CRAY VALLEY).

[0159] Examples of polyester resins include, for example, polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polybutylene naphthalate resin, polytrimethylene terephthalate resin, polytrimethylene naphthalate resin, polycyclohexanedimethyl terephthalate resin, etc.

[0160] When the thermosetting resin composition contains the component (D), the content of the component (D) is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, still more preferably 0.3% by mass or more, when the resin component in the thermosetting resin composition is 100% by mass. The upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, 6% by mass or less, or 5% by mass or less.

[0161] <(E) Inorganic filler> The thermosetting resin composition of the present invention may further contain an inorganic filler as the component (E). By containing the component (E), the linear thermal expansion coefficient and the dielectric tangent can be further reduced.

[0162] Examples of the material of the component (E) include silica, alumina, glass, cordierite, silicon oxide, barium sulfate, barium carbonate, talc, clay, mica powder, zinc oxide, hydrotalcite, boehmite, aluminum silicate, aluminum hydroxide, magnesium hydroxide, calcium carbonate, magnesium carbonate, magnesium oxide, boron nitride, aluminum nitride, manganese nitride, aluminum borate, strontium carbonate, strontium titanate, calcium titanate, magnesium titanate, bismuth titanate, titanium oxide, zirconium oxide, barium titanate, barium zirconate titanate, barium zirconate, calcium zirconate, zirconium phosphate, and zirconium tungstate phosphate, etc. Among these, silica is particularly suitable. Examples of silica include amorphous silica, fused silica, crystalline silica, synthetic silica, hollow silica, etc. Also, spherical silica is preferable as silica. The inorganic filler may be used alone, or in combination of two or more.

[0163] Examples of commercially available components of (E) include "SP60-05" and "SP507-05" from Nippon Steel Chemical & Material Co., Ltd.; "YC100C", "YA050C", "YA050C-MJE", "YA010C", "SC2500SQ", "SO-C4", "SO-C2", and "SO-C1" from Admatex Co., Ltd.; "UFP-30", "DAW-03", and "FB-105FD" from Denka Co., Ltd.; "Silfil NSS-3N", "Silfil NSS-4N", and "Silfil NSS-5N" from Tokuyama Corporation; "Cellspheres" and "MGH-005" from Taiheiyo Cement Corporation; and "Esferique" and "BA-1" from JGC Catalysts & Chemicals Co., Ltd.

[0164] The average particle size of component (E) is not particularly limited, but is preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, 2 μm or less, 1 μm or less, 0.8 μm or less, or 0.7 μm or less. The lower limit of the average particle size is not particularly limited, but is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.07 μm or more, 0.1 μm or more, or 0.2 μm or more. The average particle size of component (E) can be measured by a laser diffraction-scattering method based on Mie scattering theory. Specifically, the particle size distribution of the inorganic filler can be created on a volume basis using a laser diffraction-scattering particle size distribution analyzer, and the median diameter can be used as the average particle size. A sample can be prepared by weighing 100 mg of inorganic filler and 10 g of methyl ethyl ketone into a vial and dispersing them using ultrasound for 10 minutes. The particle size distribution of the inorganic filler was measured using a laser diffraction particle size distribution analyzer with blue and red light source wavelengths, employing a flow cell method. The average particle size was calculated as the median diameter from the obtained particle size distribution. Examples of laser diffraction particle size distribution analyzers include the "LA-960" manufactured by Horiba, Ltd.

[0165] The specific surface area of ​​component (E) is not particularly limited, but is preferably 0.1 m². 2 / g or more, more preferably 0.5m 2 / g or more, more preferably 1m2 / g or more, 3m 2 / g or more or 5m 2 The specific surface area is 100 m² or more. The upper limit of the specific surface area is not particularly limited, but is preferably 100 m². 2 / g or less, more preferably 80m 2 / g or less, more preferably 60mg 2 / g or less, 50m 2 / g or less or 40m 2 The value is less than or equal to / g. The specific surface area of ​​component (E) is obtained by adsorbing nitrogen gas onto the sample surface using a specific surface area measuring device (Macsorb HM-1210, manufactured by Mountec Co., Ltd.) according to the BET method, and then calculating the specific surface area using the BET multipoint method.

[0166] Component (E) is preferably surface-treated with a suitable surface treatment agent. Surface treatment can improve the moisture resistance and dispersibility of component (E). Examples of surface treatment agents include silane coupling agents such as vinyl silane coupling agents, epoxy silane coupling agents, styryl silane coupling agents, (meth)acrylic silane coupling agents, amino silane coupling agents, isocyanurate silane coupling agents, ureido silane coupling agents, mercapto silane coupling agents, isocyanate silane coupling agents, and acid anhydride silane coupling agents; non-silane coupling alkoxysilane compounds such as methyltrimethoxysilane and phenyltrimethoxysilane; and silazane compounds. The surface treatment agent may be used alone or in combination of two or more.

[0167] Examples of commercially available surface treatment agents include "KBM403" (3-glycidoxypropyltrimethoxysilane), "KBM803" (3-mercaptopropyltrimethoxysilane), "KBE903" (3-aminopropyltriethoxysilane), "KBM573" (N-phenyl-3-aminopropyltrimethoxysilane), and "SZ-31" (hexamethyldisilazane), all manufactured by Shin-Etsu Chemical Co., Ltd.

[0168] From the viewpoint of improving the dispersibility of the inorganic filler, the degree of surface treatment by the surface treatment agent is preferably within a predetermined range. Specifically, it is preferable that 100% by mass of the inorganic filler is surface-treated with 0.2 to 5% by mass of the surface treatment agent.

[0169] When the thermosetting resin composition of the present invention contains component (E), the content of component (E) in the thermosetting resin composition is, from the viewpoint of easily realizing a thermosetting resin composition that provides even better dielectric properties, for example, 40% by mass or more, preferably 50% by mass or more, more preferably 60% by mass or more, 65% by mass or more, or 70% by mass or more, when the nonvolatile components in the thermosetting resin composition are taken as 100% by mass. The upper limit of the content of component (E) is not particularly limited, but can be, for example, 90% by mass or less, 85% by mass or less, 80% by mass or less, etc.

[0170] The thermosetting resin composition of the present invention may further contain one or more components selected from the group consisting of organic fillers and curing accelerators.

[0171] -Organic filler- As organic fillers, a wide range of organic fillers containing rubber components can be used. Examples of rubber components in organic fillers include silicone elastomers such as polydimethylsiloxane; olefin-based thermoplastic elastomers such as polybutadiene, polyisoprene, polychlorobutadiene, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-isobutylene copolymer, acrylonitrile-butadiene copolymer, isoprene-isobutylene copolymer, isobutylene-butadiene copolymer, ethylene-propylene-diene terpolymer, and ethylene-propylene-butene terpolymer; and thermoplastic elastomers such as acrylic-based thermoplastic elastomers such as propyl poly(meth)acrylate, butyl poly(meth)acrylate, cyclohexyl poly(meth)acrylate, and octyl poly(meth)acrylate. Furthermore, silicone-based rubbers such as polyorganosiloxane rubber may be mixed into the rubber component. The rubber components contained in the rubber particles have a Tg of, for example, 0°C or lower, preferably -10°C or lower, more preferably -20°C or lower, and even more preferably -30°C or lower.

[0172] In one embodiment, the organic filler is a core-shell type rubber particle consisting of core particles containing the rubber component mentioned above and a shell portion formed by graft copolymerization of a monomer component copolymerizable with the rubber component contained in the core particles. Here, "core-shell type" does not necessarily refer only to those in which the core particles and shell portion can be clearly distinguished, but also includes those in which the boundary between the core particles and shell portion is unclear, and the core particles do not necessarily have to be completely covered by the shell portion.

[0173] Specific examples of organic fillers containing rubber components include, for example, CHT from Cheil Industries; B602 from UMGABS; Paraloid EXL-2602, Paraloid EXL-2603, Paraloid EXL-2655, Paraloid EXL-2311, Paraloid-EXL2313, Paraloid EXL-2315, Paraloid KM-330, Paraloid KM-336P, Paraloid KCZ-201 from Dow Corporation; and Metabren C-2 from Mitsubishi Rayon Corporation. Examples include "23A", "Metablen E-901", "Metablen S-2001", "Metablen W-450A", "Metablen SRK-200", Kaneka Corporation's "Kaneace M-511", "Kaneace M-600", "Kaneace M-400", "Kaneace M-580", "Kaneace MR-01", and Aica Industries Corporation's "Stafyroid AC3355", "Stafyroid AC3816", "Stafyroid AC3832", "Stafyroid AC4030", and "Stafyroid AC3364". These are core-shell type rubber particles.

[0174] When the thermosetting resin composition of the present invention contains an organic filler, the content of the organic filler in the thermosetting resin composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, and even more preferably 1.5% by mass or more or 2% by mass or more, when the resin component in the thermosetting resin composition is taken as 100% by mass. The upper limit of the content is preferably 10% by mass or less, more preferably 8% by mass or less, 6% by mass or less or 5% by mass or less.

[0175] -Curing accelerator- Examples of curing accelerators include phosphorus-based curing accelerators, amine-based curing accelerators, imidazole-based curing accelerators, guanidine-based curing accelerators, metal-based curing accelerators, and peroxide-based curing accelerators. Curing accelerators may be used individually or in combination of two or more types.

[0176] When the thermosetting resin composition of the present invention contains a curing accelerator, the content of the curing accelerator in the thermosetting resin composition is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.4% by mass or more, when the resin component in the thermosetting resin composition is taken as 100% by mass, and the upper limit is preferably 3% by mass or less, more preferably 2.5% by mass or less, or 2% by mass or less.

[0177] <Optional additives> The thermosetting resin composition of the present invention may further contain any additives. Such additives include, for example, radical polymerization initiators such as peroxide-based radical polymerization initiators and azo-based radical polymerization initiators; organometallic compounds such as organocopper compounds, organozinc compounds, and organocalt compounds; colorants such as phthalocyanine blue, phthalocyanine green, iodine green, diazo yellow, crystal violet, titanium dioxide, and carbon black; polymerization inhibitors such as hydroquinone, catechol, pyrogallol, and phenothiazine; leveling agents such as silicone-based leveling agents and acrylic polymer-based leveling agents; thickeners such as bentonite and montmorillonite; defoaming agents such as silicone-based defoaming agents, acrylic-based defoaming agents, fluorine-based defoaming agents, and vinyl resin-based defoaming agents; ultraviolet absorbers such as benzotriazole-based ultraviolet absorbers; adhesion improvers such as urea silane; triazole-based adhesion imparters, tetrazo Examples of additives include adhesion-improving agents such as oleic acid-based adhesion-improving agents and triazine-based adhesion-improving agents; antioxidants such as hindered phenol-based antioxidants; fluorescent whitening agents such as stilbene derivatives; surfactants such as fluorine-based surfactants and silicone-based surfactants; flame retardants such as phosphorus-based flame retardants (e.g., phosphate ester compounds, phosphazene compounds, phosphinic acid compounds, red phosphorus), nitrogen-based flame retardants (e.g., melamine sulfate), halogen-based flame retardants, and inorganic flame retardants (e.g., antimony trioxide); dispersants such as phosphate ester-based dispersants, polyoxyalkylene-based dispersants, acetylene-based dispersants, silicone-based dispersants, anionic dispersants, and cationic dispersants; and stabilizers such as borate-based stabilizers, titanate-based stabilizers, aluminate-based stabilizers, zirconate-based stabilizers, isocyanate-based stabilizers, carboxylic acid-based stabilizers, and carboxylic acid anhydride-based stabilizers. The content of such additives may be determined according to the properties required of the thermosetting resin composition. Furthermore, it is preferable that the thermosetting resin composition of the present invention substantially does not contain photopolymerization initiators such as photoacid generators or photoradical generators (specifically, when the resin component in the thermosetting resin composition is taken as 100% by mass, the amount of photoinitiators is less than 0.1% by mass, 0.05% by mass or less, 0.04% by mass or less, 0.02% by mass or less, 0.01% by mass or less, less than 0.01% by mass, 0.005% by mass or less, 0.001% by mass or less, and less than 0.001% by mass).

[0178] <organic solvents> The thermosetting resin composition of the present invention may further contain an organic solvent as a volatile component. Examples of organic solvents include: ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester solvents such as methyl acetate, ethyl acetate, butyl acetate, isobutyl acetate, isoamyl acetate, methyl propionate, ethyl propionate, and γ-butyrolactone; ether solvents such as tetrahydropyran, tetrahydrofuran, 1,4-dioxane, diethyl ether, diisopropyl ether, dibutyl ether, and diphenyl ether; alcohol solvents such as methanol, ethanol, propanol, butanol, and ethylene glycol; and 2-ethoxyethyl acetate, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, ethyl diglycol acetate, γ-butyrolactone, and methyl methoxypropionate. Examples include ether ester solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate; ether alcohol solvents such as 2-methoxypropanol, 2-methoxyethanol, 2-ethoxyethanol, propylene glycol monomethyl ether, and diethylene glycol monobutyl ether (butyl carbitol); amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; nitrile solvents such as acetonitrile and propionitrile; aliphatic hydrocarbon solvents such as hexane, cyclopentane, cyclohexane, and methylcyclohexane; and aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and trimethylbenzene. Organic solvents may be used individually or in combination of two or more.

[0179] The thermosetting resin composition of the present invention can be produced, for example, by adding the component (A), the component (B), and, if necessary, the component (A'), the component (C), the component (D), the component (E), an organic filler, a curing accelerator, other additives, and an organic solvent to an arbitrary preparation container in an arbitrary order and / or partially or entirely simultaneously and mixing them. Further, in the process of adding and mixing each component, the temperature can be appropriately set, and heating and / or cooling may be performed temporarily or throughout. Further, in the process of adding and mixing or thereafter, the thermosetting resin composition may be stirred or shaken using a stirring device or a shaking device such as a mixer to be uniformly dispersed. Further, defoaming may be performed under low-pressure conditions such as under vacuum simultaneously with stirring or shaking.

[0180] As described above, the thermosetting resin composition of the present invention containing the component (A) in combination with the component (B) exhibits a low dielectric tangent at room temperature and further suppresses the increase in the dielectric tangent even in a high-temperature environment, resulting in a cured product having a better dielectric tangent. Furthermore, the thermosetting resin composition of the present invention containing the component (A) in combination with the component (B) can provide a cured product having a sufficient glass transition temperature and good heat resistance, and can also provide a cured product having good reflow resistance.

[0181] In one embodiment, the cured product of the thermosetting resin composition of the present invention is characterized by having a low dielectric tangent (Df). For example, when measured at 10 GHz and 25 °C as described in Test Example 1 below, the Df of the cured product of the thermosetting resin composition of the present invention can preferably be less than 0.0035, 0.0034 or less, 0.0032 or less, 0.003 or less, or 0.0028 or less.

[0182] In one embodiment, the cured product of the thermosetting resin composition of the present invention exhibits a good dielectric loss tangent (Df) even in high-temperature environments by suppressing the increase in Df. For example, as described in Test Example 1 below, when the dielectric loss tangent measured at 10 GHz and 25°C is Df(25°C) and the dielectric loss tangent measured at 10 GHz and 90°C is Df(90°C), the rate of increase in dielectric loss tangent (%) (=(Df(90°C) - Df(25°C)) / Df(25°C) × 100) can preferably be less than 35%, 34% or less, 32% or less, 30% or less, 29% or less, or 28% or less.

[0183] In one embodiment, the cured product of the thermosetting resin composition of the present invention exhibits a sufficient glass transition temperature (Tg) and good heat resistance. For example, when thermomechanical analysis is performed using a thermomechanical analyzer (TMA) as described in Test Example 2 below, under measurement conditions of a load of 1g and a heating rate of 5°C / min, the Tg of the cured product of the thermosetting resin composition of the present invention can preferably be 145°C or higher, 146°C or higher, 148°C or higher, or 150°C or higher.

[0184] In one embodiment, the cured product of the thermosetting resin composition of the present invention exhibits good reflow resistance. For example, when a test is performed on five cured product samples by passing them through a reflow apparatus that reproduces a solder reflow temperature of 260°C peak temperature (reflow temperature profile conforming to IPC / JEDEC J-STD-020C), as described in Test Example 3 below, the number of cured product samples showing abnormalities such as blistering may preferably be two or fewer, one or fewer, or zero (none).

[0185] As described above, the thermosetting resin composition of the present invention exhibits a low dielectric loss tangent at room temperature and can further suppress the increase in dielectric loss tangent even at high temperatures, resulting in a cured product with an even better dielectric loss tangent. Therefore, the thermosetting resin composition of the present invention can be suitably used as a thermosetting resin composition for forming an insulating layer of a printed wiring board (thermosetting resin composition for insulating layer of printed wiring board), and can be suitably used as a thermosetting resin composition for forming an interlayer insulating layer of a printed wiring board (thermosetting resin composition for interlayer insulating layer of printed wiring board). The thermosetting resin composition of the present invention can also be suitably used when the printed wiring board is a circuit board with embedded components. The thermosetting resin composition of the present invention can also be suitably used as a thermosetting resin composition for forming an insulating layer of a redistribution substrate for a semiconductor package (thermosetting resin composition for insulating layer of redistribution substrate). In the present invention, printed wiring boards and redistribution substrates are collectively referred to as "circuit boards," and therefore the thermosetting resin composition of the present invention can be suitably used for the insulating layer of a circuit board.

[0186] The thermosetting resin composition of the present invention can be used in a wide range of applications where a thermosetting resin composition is required, such as sheet-like laminated materials like resin sheets and prepregs, solder resists, underfill materials, die bonding materials, hole-filling resins, sealing resins, and component embedding resins.

[0187] [Sheet-like laminated materials (resin sheets, prepregs)] The thermosetting resin composition of the present invention can be used as is, or it may be used in the form of a sheet-like laminate material containing the thermosetting resin composition.

[0188] As sheet-like laminated materials, the following resin sheets and prepregs are preferred.

[0189] In one embodiment, the resin sheet comprises a support and a layer of a thermosetting resin composition provided on the support (hereinafter simply referred to as the "thermosetting resin composition layer"), characterized in that the thermosetting resin composition layer is formed from the thermosetting resin composition of the present invention.

[0190] The optimal thickness of the thermosetting resin composition layer varies depending on the application and may be determined appropriately according to the application. For example, from the viewpoint of thinning printed circuit boards and semiconductor packages, the thickness of the thermosetting resin composition layer is preferably 100 μm or less, 80 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, or 30 μm or less. The lower limit of the thickness of the thermosetting resin composition layer is not particularly limited, but can usually be 1 μm or more, 5 μm or more, etc.

[0191] Examples of support materials include thermoplastic resin films, metal foils, and release paper, with thermoplastic resin films and metal foils being preferred. Therefore, in one preferred embodiment, the support material is a thermoplastic resin film or a metal foil.

[0192] When using a thermoplastic resin film as a support, examples of thermoplastic resins include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), acrylics such as polycarbonate (PC) and polymethyl methacrylate (PMMA), cyclic polyolefins, triacetylcellulose (TAC), polyether sulfide (PES), polyether ketones, and polyimides. Among these, polyethylene terephthalate and polyethylene naphthalate are preferred, and inexpensive polyethylene terephthalate is particularly preferred.

[0193] When using metal foil as a support, examples of metal foil include copper foil and aluminum foil, with copper foil being preferred. As for copper foil, foil made of single-metal copper may be used, or foil made of an alloy of copper with another metal (for example, tin, chromium, silver, magnesium, nickel, zirconium, silicon, titanium, etc.) may be used.

[0194] The support may have a matte finish, corona treatment, or antistatic treatment applied to the surface that joins with the thermosetting resin composition layer. Alternatively, a support with a release layer may be used, which has a release layer on the surface that joins with the thermosetting resin composition layer. Examples of release agents used in the release layer of the support with a release layer include one or more release agents selected from the group consisting of alkyd resins, polyolefin resins, urethane resins, and silicone resins. Commercially available support with a release layer may be used, for example, PET films having a release layer mainly composed of an alkyd resin-based release agent, such as "SK-1", "AL-5", and "AL-7" from Lintec Corporation, "Lumirror T60" from Toray Industries, Inc., "Purex" from Teijin Corporation, and "Unipeel" from Unitika Corporation.

[0195] The thickness of the support is not particularly limited, but is preferably in the range of 5 μm to 75 μm, and more preferably in the range of 10 μm to 60 μm. When using a support with a release layer, it is preferable that the overall thickness of the support with the release layer is within the above range.

[0196] When using metal foil as a support, a metal foil with a support substrate, which is formed by laminating a peelable support substrate onto a thin metal foil, may be used. In one embodiment, the metal foil with a support substrate includes a support substrate, a release layer provided on the support substrate, and a metal foil provided on the release layer. When using metal foil with a support substrate as a support, the thermosetting resin composition layer is provided on the metal foil.

[0197] In a metal foil with a support substrate, the material of the support substrate is not particularly limited, but examples include copper foil, aluminum foil, stainless steel foil, titanium foil, copper alloy foil, etc. When copper foil is used as the support substrate, it may be electrolytic copper foil or rolled copper foil. Furthermore, the release layer is not particularly limited as long as it can be used to peel the metal foil from the support substrate, and examples include an alloy layer of elements selected from the group consisting of Cr, Ni, Co, Fe, Mo, Ti, W, and P; an organic coating, etc.

[0198] In a metal foil with a support substrate, the material of the metal foil is preferably, for example, copper foil or copper alloy foil.

[0199] In a metal foil with a support substrate, the thickness of the support substrate is not particularly limited, but is preferably in the range of 10 μm to 150 μm, and more preferably in the range of 10 μm to 100 μm. The thickness of the metal foil may be, for example, in the range of 0.1 μm to 10 μm.

[0200] In one embodiment, the resin sheet may further include any additional layer as needed. Such an additional layer may be, for example, a protective film provided on the side of the thermosetting resin composition layer that is not bonded to the support (i.e., the side opposite to the support). The thickness of the protective film is not particularly limited, but is, for example, 1 μm to 40 μm. By laminating the protective film, the adhesion of dust and other debris to the surface of the thermosetting resin composition layer and scratches can be suppressed.

[0201] Resin sheets can be manufactured, for example, by applying a liquid thermosetting resin composition as is, or by preparing a resin varnish by dissolving the thermosetting resin composition in an organic solvent, applying this varnish to a support using a die coater or the like, and then drying it to form a thermosetting resin composition layer.

[0202] Examples of organic solvents include those similar to those described as components of thermosetting resin compositions. Organic solvents may be used individually or in combination of two or more.

[0203] Drying may be carried out by known methods such as heating or blowing hot air. The drying conditions are not particularly limited, but the drying should be carried out so that the content of the organic solvent in the thermosetting resin composition layer is 10% by mass or less, preferably 5% by mass or less. Depending on the boiling point of the organic solvent in the thermosetting resin composition or resin varnish, for example, when using a thermosetting resin composition or resin varnish containing 30% to 60% by mass of organic solvent, the thermosetting resin composition layer can be formed by drying at 50°C to 150°C for 3 to 10 minutes.

[0204] Resin sheets can be stored by rolling them up. If the resin sheet has a protective film, it can be used after removing the protective film.

[0205] In one embodiment, the prepreg is formed by impregnating a sheet-like fibrous substrate with the thermosetting resin composition of the present invention.

[0206] The sheet-like fibrous substrate used for the prepreg is not particularly limited, and commonly used prepreg substrates such as glass cloth, aramid nonwoven fabric, and liquid crystal polymer nonwoven fabric can be used. From the viewpoint of thinning printed circuit boards and semiconductor chip packages, the thickness of the sheet-like fibrous substrate is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 30 μm or less, and particularly preferably 20 μm or less. The lower limit of the thickness of the sheet-like fibrous substrate is not particularly limited, but is usually 10 μm or more.

[0207] Prepregs can be manufactured by known methods such as the hot melt method and the solvent method.

[0208] The thickness of the prepreg can be within the same range as the thermosetting resin composition layer in the resin sheet described above.

[0209] The sheet-like laminated material of the present invention can be suitably used to form an insulating layer of a printed circuit board (for the insulating layer of a printed circuit board), and more suitably used to form an interlayer insulating layer of a printed circuit board (for the insulating edge layer of a printed circuit board). The sheet-like laminated material of the present invention can also be suitably used to form an insulating layer of a redistribution substrate for a semiconductor package (for the insulating layer of a redistribution substrate). In other words, the sheet-like laminated material of the present invention can be suitably used as an insulating layer for a circuit board.

[0210] [Circuit board] An insulating layer of a circuit board can be formed using the thermosetting resin composition of the present invention. The present invention also provides such a circuit board, that is, a circuit board including an insulating layer made of a cured product of the thermosetting resin composition of the present invention.

[0211] <Printed wiring board> In one embodiment, the circuit board of the present invention is a printed wiring board.

[0212] Printed circuit boards can be manufactured, for example, using the above-mentioned resin sheet by a method including the following steps (I) and (II). (I) A process of laminating a resin sheet onto an inner layer substrate such that the thermosetting resin composition layer of the resin sheet is bonded to the inner layer substrate. (II) A process of forming an insulating layer by thermal curing the thermosetting resin composition layer.

[0213] The "internal layer substrate" used in process (I) is a material that serves as the substrate for a printed wiring board, and examples include glass epoxy substrates, metal substrates, polyester substrates, polyimide substrates, BT resin substrates, thermosetting polyphenylene ether substrates, etc. The substrate may also have a conductive layer on one or both sides, and this conductive layer may be patterned. An internal layer substrate in which a conductive layer (circuit) is formed on one or both sides of the substrate is sometimes called an "internal layer circuit board." Furthermore, an intermediate product on which an insulating layer and / or a conductive layer is to be formed during the manufacturing of a printed wiring board is also included in the "internal layer substrate" as defined in this invention. If the printed wiring board is a circuit board with embedded components, an internal layer substrate with embedded components may be used.

[0214] The lamination of the inner layer substrate and the resin sheet can be performed, for example, by heating and pressing the resin sheet onto the inner layer substrate from the support side. Examples of the heating and pressing member used to heat and press the resin sheet onto the inner layer substrate (hereinafter also referred to as the "heat pressing member") include a heated metal plate (such as a SUS end plate) or a metal roll (such as a SUS roll). The heating and pressing member may be pressed directly onto the resin sheet, or it may be pressed via an elastic material such as heat-resistant rubber so that the resin sheet can adequately follow the surface irregularities of the inner layer substrate.

[0215] Lamination of the inner layer substrate and the resin sheet may be carried out by a vacuum lamination method. In the vacuum lamination method, the heat-pressure temperature is preferably in the range of 60°C to 160°C, more preferably in the range of 80°C to 140°C, the heat-pressure pressure is preferably in the range of 0.098 MPa to 1.77 MPa, more preferably in the range of 0.29 MPa to 1.47 MPa, and the heat-pressure time is preferably in the range of 20 seconds to 400 seconds, more preferably in the range of 30 seconds to 300 seconds. Lamination may preferably be carried out under reduced pressure conditions of 26.7 hPa or less.

[0216] Lamination can be performed using a commercially available vacuum laminator. Examples of commercially available vacuum laminators include vacuum pressure laminators manufactured by Meiki Seisakusho Co., Ltd., vacuum applicators manufactured by Nikko Materials Co., Ltd., and batch-type vacuum pressure laminators.

[0217] After lamination, the laminated resin sheets may be smoothed by pressing a heat-sealing member from the support side under normal pressure (atmospheric pressure). The pressing conditions for the smoothing process can be the same as the heat-sealing conditions for lamination. The smoothing process can be performed using a commercially available laminator. Lamination and smoothing may be performed continuously using the commercially available vacuum laminator mentioned above.

[0218] The support may be removed between steps (I) and (II), or after step (II). If a metal foil is used as the support, the conductive layer may be formed using the metal foil without peeling off the support. If a metal foil with a support substrate is used as the support, the support substrate (and release layer) should be peeled off. Then, the conductive layer can be formed using the metal foil.

[0219] In step (II), the thermosetting resin composition layer is thermocured to form an insulating layer made of the cured product of the thermosetting resin composition. The curing conditions for the thermosetting resin composition layer are not particularly limited, and conditions that are normally used when forming an insulating layer of a printed circuit board may be used.

[0220] For example, the thermosetting conditions for the thermosetting resin composition layer vary depending on the type of thermosetting resin composition, but in one embodiment, the curing temperature is preferably 140°C to 250°C, more preferably 150°C to 240°C, and even more preferably 170°C to 230°C. The curing time can be preferably 5 minutes to 240 minutes, more preferably 10 minutes to 150 minutes, and even more preferably 15 minutes to 120 minutes.

[0221] Prior to thermal curing the thermosetting resin composition layer, the thermosetting resin composition layer may be preheated at a temperature lower than the curing temperature. For example, prior to thermal curing the thermosetting resin composition layer, the thermosetting resin composition layer may be preheated at a temperature of 50°C to 140°C, preferably 60°C to 135°C, more preferably 70°C to 130°C for 5 minutes or more, preferably 5 minutes to 150 minutes, more preferably 15 minutes to 120 minutes, and even more preferably 15 minutes to 100 minutes.

[0222] In manufacturing printed circuit boards, the following steps may be further performed: (III) drilling holes in the insulating layer, (IV) roughening the insulating layer, and (V) forming the conductor layer. These steps (III) through (V) may be carried out according to various methods known to those skilled in the art that are used in the manufacture of printed circuit boards. If the support is removed after step (II), the removal of the support may be carried out between steps (II) and (III), between steps (III) and (IV), or between steps (IV) and (V). Furthermore, if necessary, the formation of the insulating layer and the conductor layer in steps (I) through (V) may be repeated to form a multilayer circuit board.

[0223] In other embodiments, the printed circuit board of the present invention can be manufactured using the prepreg described above. The manufacturing method is basically the same as when a resin sheet is used.

[0224] Step (III) is a step of drilling holes in the insulating layer, thereby forming holes such as via holes and through holes in the insulating layer. Step (III) may be carried out using, for example, a drill, laser, plasma, etc., depending on the composition of the thermosetting resin composition used to form the insulating layer. The dimensions and shape of the holes may be appropriately determined according to the design of the printed circuit board.

[0225] Step (IV) is a process for roughening the insulating layer. Typically, smear removal (desmear) is also performed in this step (IV). The procedure and conditions for the roughening process are not particularly limited, and known procedures and conditions commonly used when forming the insulating layer of a printed circuit board can be adopted. For example, the insulating layer can be roughened by performing swelling treatment with a swelling solution, roughening treatment with an oxidizing agent, and neutralization treatment with a neutralizing solution in this order.

[0226] The swelling solution used for the roughening treatment is not particularly limited, but examples include alkaline solutions and surfactant solutions, and is preferably an alkaline solution, with sodium hydroxide solution and potassium hydroxide solution being more preferred. Examples of commercially available swelling solutions include "Swelling Dip Securing P" and "Swelling Dip Securing SBU" manufactured by Atotec Japan. The swelling treatment with the swelling solution is not particularly limited, but can be carried out, for example, by immersing the insulating layer in a swelling solution at 30°C to 90°C for 1 to 20 minutes. From the viewpoint of suppressing the swelling of the resin of the insulating layer to an appropriate level, it is preferable to immerse the insulating layer in a swelling solution at 40°C to 80°C for 5 to 15 minutes.

[0227] The oxidizing agent used for the roughening treatment is not particularly limited, but examples include an alkaline permanganate solution obtained by dissolving potassium permanganate or sodium permanganate in an aqueous solution of sodium hydroxide. The roughening treatment with an oxidizing agent such as an alkaline permanganate solution is preferably carried out by immersing the insulating layer in an oxidizing agent solution heated to 60°C to 100°C for 10 to 30 minutes. Furthermore, the concentration of permanganate in the alkaline permanganate solution is preferably 5% to 10% by mass. Examples of commercially available oxidizing agents include alkaline permanganate solutions such as "Concentrate Compact CP" and "Dosing Solution Securigans P" manufactured by Attec Japan.

[0228] Furthermore, an acidic aqueous solution is preferred as the neutralizing solution used in the roughening treatment. A commercially available example is "Reduction Solution Securigant P" manufactured by Attec Japan.

[0229] The neutralization treatment can be carried out by immersing the treated surface, which has been roughened with an oxidizing agent, in a neutralization solution at 30°C to 80°C for 5 to 30 minutes. From the standpoint of workability, it is preferable to immerse the object, which has been roughened with an oxidizing agent, in a neutralization solution at 40°C to 70°C for 5 to 20 minutes.

[0230] Step (V) is a step of forming a conductive layer, in which a conductive layer is formed on an insulating layer. The conductive material used for the conductive layer is not particularly limited. In a preferred embodiment, the conductive layer contains one or more metals selected from the group consisting of gold, platinum, palladium, silver, copper, aluminum, cobalt, chromium, zinc, nickel, titanium, tungsten, iron, tin, and indium. The conductive layer may be a single-metal layer or an alloy layer, and examples of alloy layers include layers formed from alloys of two or more metals selected from the above group (e.g., nickel-chromium alloy, copper-nickel alloy, and copper-titanium alloy). In particular, from the viewpoint of versatility in conductor layer formation, cost, and ease of patterning, single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy, copper-nickel alloy, or copper-titanium alloy are preferred, single metal layers of chromium, nickel, titanium, aluminum, zinc, gold, palladium, silver, or copper, or alloy layers of nickel-chromium alloy are more preferred, and single metal layers of copper are even more preferred.

[0231] The conductive layer may be a single-layer structure, or it may be a multi-layer structure in which two or more single-metal layers or alloy layers made of different types of metals or alloys are laminated. When the conductive layer is a multi-layer structure, the layer in contact with the insulating layer is preferably a single-metal layer of chromium, zinc, or titanium, or an alloy layer of nickel-chromium alloy.

[0232] The thickness of the conductor layer depends on the desired printed circuit board design, but is generally 3 μm to 35 μm, preferably 5 μm to 30 μm.

[0233] In one embodiment, the conductor layer may be formed by plating. From the viewpoint of facilitating the formation of fine wiring, it is preferable to form it by a semi-additive method. An example of forming the conductor layer by a semi-additive method is shown below.

[0234] First, a plating seed layer is formed on the surface of the insulating layer by electroless plating. Next, a mask pattern is formed on the formed plating seed layer, exposing a portion of the plating seed layer corresponding to the desired wiring pattern. After forming a metal layer on the exposed plating seed layer by electroplating, the mask pattern is removed. Subsequently, the unnecessary plating seed layer can be removed by etching or other means to form a conductor layer having the desired wiring pattern.

[0235] In other embodiments, the conductor layer may be formed using metal foil. When forming the conductor layer using metal foil, step (V) is preferably performed between steps (I) and (II). For example, after step (I), the support is removed and the metal foil is laminated onto the surface of the exposed thermosetting resin composition layer. The lamination of the thermosetting resin composition layer and the metal foil may be carried out by a vacuum lamination method. The lamination conditions may be the same as those described for step (I). Next, step (II) is performed to form an insulating layer. Subsequently, the metal foil on the insulating layer can be used to form a conductor layer having a desired wiring pattern by conventional known techniques such as the modified semi-additive method.

[0236] Metal foils can be manufactured by known methods such as electrolysis and rolling. Examples of commercially available metal foils include HLP foil and JXUT-III foil manufactured by JX Metals, and 3EC-III foil and TP-III foil manufactured by Mitsui Mining & Smelting Co., Ltd.

[0237] Alternatively, as mentioned above, if a metal foil or a metal foil with a support substrate is used as the support for the resin sheet, the conductive layer may be formed using the metal foil.

[0238] <Semiconductor package redistribution substrate> In one embodiment, the circuit board of the present invention is a redistribution substrate (redistribution layer) for a semiconductor package. The following description will be based on the manufacturing method of the semiconductor package.

[0239] The semiconductor package includes an insulating layer made of a cured product of the thermosetting resin composition of the present invention as an insulating layer of the redistribution substrate. The semiconductor package may also include a sealing layer made of a cured product of the thermosetting resin composition of the present invention.

[0240] A semiconductor package can be manufactured, for example, using the thermosetting resin composition and resin sheet of the present invention by a method including the following steps (1) to (6). The thermosetting resin composition and resin sheet of the present invention may be used to form the redistribution layer (insulating layer for forming a redistribution substrate) in step (5) or the sealing layer in step (3). An example of forming a redistribution layer and a sealing layer using the thermosetting resin composition and resin sheet is shown below, but the techniques for forming redistribution layers and sealing layers of semiconductor packages are well known, and those skilled in the art can manufacture semiconductor packages using the thermosetting resin composition and resin sheet of the present invention in accordance with known techniques. (1) A step of laminating a temporary fixing film onto the substrate, (2) A step of temporarily fixing the semiconductor chip onto a temporary fixing film, (3) A step of forming a sealing layer on a semiconductor chip, (4) Steps to peel off the substrate and temporary fixing film from the semiconductor chip, (5) A step of forming a rewiring layer as an insulating layer on the surface from which the substrate and temporary fixing film of the semiconductor chip have been peeled off, and (6) Step of forming a redistribution layer as a conductor layer on the redistribution formation layer.

[0241] -Process (1)- The material used for the substrate is not particularly limited. Examples of substrates include semiconductor wafers such as silicon wafers; glass wafers; glass substrates; metal substrates such as copper, titanium, stainless steel, and cold-rolled steel sheets (SPCC); substrates made by impregnating glass fibers with epoxy resin and heat-curing them (e.g., FR-4 substrates); and substrates made of bismaleimidotriazine resin (BT resin).

[0242] The temporary fixing film is not limited in material as long as it can be peeled off from the semiconductor chip in step (4) and temporarily fix the semiconductor chip. A commercially available temporary fixing film can be used. Examples of commercially available products include Riva Alpha manufactured by Nitto Denko Corporation.

[0243] -Process (2)- Temporary fixing of semiconductor chips can be performed using known devices such as flip-chip bonders and die bonders. The layout and number of semiconductor chips can be appropriately set according to the shape and size of the temporary fixing film, the number of semiconductor packages to be produced, etc. For example, they can be temporarily fixed in a matrix arrangement with multiple rows and multiple columns.

[0244] -Process (3)- The thermosetting resin composition layer of the resin sheet of the present invention is laminated onto a semiconductor chip, or the thermosetting resin composition of the present invention is applied onto a semiconductor chip and cured (e.g., by thermosetting) to form a sealing layer.

[0245] For example, lamination of a semiconductor chip and a resin sheet can be performed by removing the protective film from the resin sheet and then heating and pressing the resin sheet onto the semiconductor chip from the support side. Examples of the heating and pressing member used to heat and press the resin sheet onto the semiconductor chip (hereinafter also referred to as the "heating and pressing member") include a heated metal plate (such as a SUS end plate) or a metal roll (such as a SUS roll). It is preferable to press the resin sheet via an elastic material such as heat-resistant rubber, rather than directly pressing the heating and pressing member onto the resin sheet, so that the resin sheet can adequately follow the surface irregularities of the semiconductor chip. Lamination of the semiconductor chip and the resin sheet may also be carried out by a vacuum lamination method, and the lamination conditions are the same as those described in relation to the manufacturing method of printed circuit boards, and the preferred range is also the same.

[0246] After lamination, a thermosetting resin composition is thermocured to form a sealing layer. The thermocuring conditions are the same as those described in relation to the manufacturing method of printed circuit boards.

[0247] The resin sheet support may be peeled off after the resin sheet has been laminated onto the semiconductor chip and heat-cured, or the support may be peeled off before the resin sheet has been laminated onto the semiconductor chip.

[0248] When applying the thermosetting resin composition of the present invention to form a sealing layer, the application conditions are the same as those for forming the thermosetting resin composition layer described in relation to the resin sheet of the present invention, and the preferred range is also the same.

[0249] -Process (4)- The method for peeling off the substrate and the temporary fixing film can be appropriately changed depending on the material of the temporary fixing film, etc. Examples include a method of peeling off the temporary fixing film by heating and foaming (or expanding) it, and a method of peeling off the temporary fixing film by irradiating it with ultraviolet light from the substrate side to reduce the adhesive strength of the temporary fixing film.

[0250] In the method of peeling off a temporary fixing film by heating and foaming (or expanding) it, the heating conditions are usually 100-250°C for 1-90 seconds or 5-15 minutes. In the method of peeling off a temporary fixing film by irradiating it with ultraviolet light from the substrate side to reduce its adhesive strength, the amount of ultraviolet light irradiated is usually 10 mJ / cm². 2 ~1000 mJ / cm 2 That is the case.

[0251] -Process (5)- The thermosetting resin composition and resin sheet of the present invention are used to form a rewiring layer (insulating layer of a rewiring substrate).

[0252] After forming the redistribution layer, via holes may be formed in the redistribution layer to interlayer connect the semiconductor chip with the conductor layer described later. The via holes may be formed by known methods depending on the material of the redistribution layer.

[0253] -Process (6)- The formation of the conductor layer on the rewiring layer may be carried out in the same manner as in step (V) described in relation to the manufacturing method of a printed circuit board. Alternatively, steps (5) and (6) may be repeated to alternately stack the conductor layer (rewiring layer) and the rewiring layer (insulating layer) (build-up).

[0254] In manufacturing a semiconductor package, the following steps may be further performed: (7) forming a solder resist layer on a conductor layer (redistribution layer), (8) forming bumps, and (9) dicing multiple semiconductor packages into individual semiconductor packages to form individual pieces. These steps may be carried out in accordance with various methods known to those skilled in the art that are used in the manufacture of semiconductor packages.

[0255] The thermosetting resin composition and resin sheet of the present invention can produce a cured product that exhibits a low dielectric loss tangent at room temperature and further suppresses the increase in dielectric loss tangent even at high temperatures, resulting in an even better dielectric loss tangent. By forming a redistribution layer (insulating layer) using these materials, it is possible to realize a semiconductor package with extremely low transmission loss, regardless of whether the semiconductor package is a fan-in or fan-out type package. In one embodiment, the semiconductor package of the present invention is a fan-out type package. The thermosetting resin composition and resin sheet of the present invention can be applied to fan-out type panel-level packages (FOPLPs) and fan-out type wafer-level packages (FOWLPs). In one embodiment, the semiconductor package of the present invention is a fan-out type panel-level package (FOPLP) or a fan-out type wafer-level package (FOWLP).

[0256] [Semiconductor device] The semiconductor device of the present invention includes a layer made of a cured product of the thermosetting resin composition layer of the present invention. The semiconductor device of the present invention can be manufactured using the circuit board of the present invention.

[0257] Examples of semiconductor devices include various types of semiconductor devices used in electrical products (e.g., computers, mobile phones, digital cameras, and televisions) and vehicles (e.g., motorcycles, automobiles, trains, ships, and aircraft). [Examples]

[0258] The present invention will be described in detail below with reference to examples. The present invention is not limited to these examples. In the following, unless otherwise specified, "parts" and "%" refer to "parts by mass" and "% by mass," respectively.

[0259] <Example 1: Preparation of thermosetting resin composition 1> Three parts of aliphatic monofunctional epoxy resin (EX-121, manufactured by Nagase ChemteX, with an epoxy equivalent of approximately 187 g / eq, and a structure represented by the following formula (A-1)), six parts of biphenyl-type epoxy resin (NC3000L, manufactured by Nippon Kayaku Co., Ltd., with an epoxy equivalent of approximately 271 g / eq), and thirteen parts of naphthalene-type epoxy resin (HP4032SS, manufactured by DIC Corporation, with an epoxy equivalent of approximately 144 g / eq) were heated and dissolved in 20 parts of toluene and 20 parts of MEK while stirring. After cooling the resulting solution to room temperature, 42 parts of a radical polymerizable compound (DIC Corporation's "NE-V-1100-70T", unsaturated bond equivalent 428 g / eq, toluene solution with 70% non-volatile components), 6 parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation's "LA-3018-50P", hydroxyl group equivalent approximately 151 g / eq, 2-methoxypropanol solution with 50% non-volatile components), and a carbodiimide curing agent (Nisshinbo Chemical Corporation's "V-03", active group equivalent 216 g / eq, toluene solution with 50% non-volatile components) were added. One part of ), one part of phenoxy resin (Mitsubishi Chemical's "YX7553BH30", a MEK / cyclohexanone mixed solution with 30% non-volatile components), five parts of a curing accelerator (Shikoku Chemicals' "1B2PZ", a MEK solution with 10% non-volatile components), and 180 parts of an inorganic filler (spherical silica (Admatex's "SO-C2", average particle size 0.5 μm) surface-treated with an amine-based silane coupling agent (Shin-Etsu Chemical's "KBM573")) were mixed and uniformly dispersed in a high-speed rotary mixer to obtain thermosetting resin composition 1.

[0260] [ka]

[0261] <Example 2: Preparation of Thermosetting Resin Composition 2> (1) Replaced 3 parts of aliphatic monofunctional epoxy resin (Nagase ChemteX "EX-121") with 3 parts of aliphatic monofunctional epoxy resin (Cargill "Vikolox(registered trademark)-14", epoxy equivalent approximately 212 g / eq, structure represented by formula (A-2) below), (2) Changed the amount of naphthalene-type epoxy resin (DIC "HP4032SS") from 13 parts to 7 parts, (3) Added 15 parts of naphthalene-type epoxy resin (Nippon Steel Chemical & Material "ESN475V", epoxy equivalent approximately 332 g / eq), (4) Radical polymerizable compound (DIC "NE-V-1100) Thermosetting resin composition 2 was obtained in the same manner as in Example 1, except that (5) the amount of -70T was changed from 42 parts to 25 parts, (5) 20 parts of an active ester curing agent (DIC Corporation's "HP-B-8151-62T", active group equivalent 238 g / eq, toluene solution with 62% nonvolatile components) were added, (6) 1 part of polystyrene resin (Asahi Kasei Corporation's "ToughTec P2000", toluene solution with 33.3% nonvolatile components) was used instead of 1 part of phenoxy resin (Mitsubishi Chemical Corporation's "YX7553BH30"), and (7) 2 parts of core-shell type rubber particles (Aica Kogyo Co., Ltd.'s "AC3816N", average particle size 0.5 μm) were added.

[0262] [ka]

[0263] <Example 3: Preparation of Thermosetting Resin Composition 3> Thermosetting resin composition 3 was obtained in the same manner as in Example 1, except that (1) 9 parts of aliphatic monofunctional epoxy resin (Nagase ChemteX Corporation's "EX-171", epoxy equivalent approximately 971 g / eq, structure represented by the following formula (A-3) (wherein m is 15)) were used instead of 3 parts of aliphatic monofunctional epoxy resin (Nagase ChemteX Corporation's "EX-121"), (2) 3 parts of naphthalene-type epoxy resin (DIC Corporation's "HP4700", epoxy equivalent approximately 162 g / eq) were added, (3) a carbodiimide-based curing agent (Nisshinbo Chemical Corporation's "V-03") was not used, and (4) 1 part of core-shell type rubber particles (Aica Industrial Co., Ltd.'s "AC3816N", average particle size 0.5 μm) was added.

[0264] [ka]

[0265] <Example 4: Preparation of Thermosetting Resin Composition 4> (1) Replace 3 parts of aliphatic monofunctional epoxy resin (Nagase ChemteX "EX-121") with aliphatic monofunctional epoxy resin (ADEKA "ED-502", epoxy equivalent approximately 320 g / eq, structure represented by the following formula (A-4) (wherein R A4 is C 12 H 25 and C 13 H 27 ;C 12 , C 13 Thermosetting resin composition 4 was obtained in the same manner as in Example 1, except that (2) three parts of a mixture were used, (3) three parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation's "LA-1356", hydroxyl group equivalent of approximately 146 g / eq, MEK solution with 60% non-volatile components) and four parts of a biphenyl skeleton phenolic curing agent (Nippon Kayaku Co., Ltd.'s "GPH-65", MEK solution with 50% non-volatile components) were used instead of six parts of a triazine skeleton-containing phenolic curing agent (DIC Corporation's "LA-3018-50P"), and (4) four parts of a radical polymerizable compound (Nippon Steel Chemical & Material Co., Ltd.'s "ODV-XET-X04", toluene mixed solution with 65% non-volatile components) were added.

[0266] [ka]

[0267] <Example 5: Preparation of thermosetting resin composition 5> Thermosetting resin composition 5 was obtained in the same manner as in Example 1, except that (1) 0.5 parts of aliphatic monofunctional epoxy resin (ADEKA Corporation, "ED-502", epoxy equivalent approximately 320 g / eq, structure represented by the above formula (A-4)) were used instead of 3 parts of aliphatic monofunctional epoxy resin (Nagase ChemteX Corporation, "EX-121"), and (2) 3 parts of a radical polymerizable compound (Shin Nakamura Chemical Co., Ltd., "A-DOG", molecular weight 326) were added.

[0268] <Example 6: Preparation of thermosetting resin composition 6> (1) Instead of 3 parts of aliphatic monofunctional epoxy resin ("EX-121" manufactured by Nagase ChemteX Corporation), 3 parts of aliphatic monofunctional epoxy resin ("ED-502" manufactured by ADEKA Corporation, epoxy equivalent approximately 320 g / eq, structure represented by the above formula (A-4)) were used. (2) Instead of 13 parts of naphthalene-type epoxy resin ("HP4032SS" manufactured by DIC Corporation), 17 parts of bisphenol A-type epoxy resin ("jER828EL" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent approximately 189 g / eq) were used. (3) Instead of 42 parts of radical polymerizable compound ("NE-V-1100-70T" manufactured by DIC Corporation, unsaturated bond equivalent 428 g / eq, toluene solution with 70% nonvolatile components), radical polymerizable compound ("O" manufactured by Mitsubishi Gas Chemical Corporation) were used. Thermosetting resin composition 6 was obtained in the same manner as in Example 1, except that (4) 5 parts of "PE-2St", a toluene solution with a number average molecular weight of 1200 and 65% non-volatile components were used, (4) 53 parts of an active ester curing agent (DIC Corporation's "HPC-8000L-65MT", an active group equivalent of 220 g / eq, a MEK-toluene mixed solution with 65% non-volatile components) were added, (5) the amount of curing accelerator (Shikoku Chemicals, Inc.'s "1B2PZ", a MEK solution with 10% non-volatile components) was changed from 5 parts to 3 parts, (6) 1 part of a curing accelerator (4-dimethylaminopyridine (DMAP), a MEK solution with 10% non-volatile components) was added, and (7) a carbodiimide curing agent (Nisshinbo Chemical Corporation's "V-03") was not used.

[0269] <Example 7: Preparation of thermosetting resin composition 7> Thermosetting resin composition 7 was obtained in the same manner as in Example 1, except that (1) three parts of aliphatic monofunctional epoxy resin (DY-BP, manufactured by Yokkaichi Gosei Co., Ltd., epoxy equivalent of approximately 130 g / eq, structure represented by the following formula (A-5)) were used instead of three parts of aliphatic monofunctional epoxy resin (EX-121, manufactured by Nagase ChemteX Corporation), (2) a carbodiimide-based curing agent (V-03, manufactured by Nisshinbo Chemical Co., Ltd.) was not used, and (3) six parts of a radical polymerizable compound (SA9000, manufactured by SABIC, number average molecular weight 1850-1950, MEK-cyclohexanone mixed solution with 50% non-volatile components) were added.

[0270] [ka]

[0271] <Example 8: Preparation of thermosetting resin composition 8> Thermosetting resin composition 8 was obtained in the same manner as in Example 1, except that three parts of an aliphatic monofunctional epoxy resin (Nissan Chemical Corporation's "FOLDI-E101", epoxy equivalent approximately 340 g / eq, structure represented by the following formula (A-6)) were used instead of three parts of the aliphatic monofunctional epoxy resin (Nagase ChemteX Corporation's "EX-121") in Example 1.

[0272] [ka]

[0273] <Comparative Example 1: Preparation of Thermosetting Resin Composition 8> Thermosetting resin composition 8 was obtained in the same manner as in Example 1, except that (1) an aliphatic monofunctional epoxy resin (EX-121, manufactured by Nagase ChemteX Corporation) was not used, (2) the amount of radical polymerizable compound (NE-V-1100-70T, manufactured by DIC Corporation, with an unsaturated bond equivalent of 428 g / eq and a toluene solution with 70% non-volatile components) was changed from 42 parts to 47 parts, and (3) 2 parts of core-shell type rubber particles (AC3816N, manufactured by Aica Kogyo Co., Ltd., with an average particle size of 0.5 μm) were added.

[0274] <Comparative Example 2: Preparation of Thermosetting Resin Composition 9> Thermosetting resin composition 9 was obtained in the same manner as in Example 1, except that (1) 1.5 parts of aliphatic bifunctional epoxy resin (Daicel Corporation's "Celoxide 2021P", epoxy equivalent approximately 136 g / eq, structure represented by the following formula (A'-1)) were used instead of 3 parts of aliphatic monofunctional epoxy resin (Nagase ChemteX Corporation's "EX-121"), (2) the amount of radical polymerizable compound (DIC Corporation's "NE-V-1100-70T", unsaturated bond equivalent 428 g / eq, toluene solution with 70% solids) was changed from 42 parts to 47 parts, and (3) 2 parts of core-shell type rubber particles (Aica Industrial Co., Ltd.'s "AC3816N", average particle size 0.5 μm) were added.

[0275] [ka]

[0276] <Comparative Example 3: Preparation of Thermosetting Resin Composition 10> Thermosetting resin composition 10 was obtained in the same manner as in Example 1, except that (1) three parts of aromatic monofunctional epoxy resin (ADEKA "ED-509E", epoxy equivalent approximately 210 g / eq, structure represented by the following formula (A'-2)) were used instead of three parts of aliphatic monofunctional epoxy resin (Nagase ChemteX "EX-121"), and (2) the amount of inorganic filler (spherical silica surface-treated with an amine-based silane coupling agent (Shin-Etsu Chemical Co., Ltd. "KBM573") (Admatex "SO-C2", average particle size 0.5 μm)) was changed from 180 parts to 150 parts.

[0277] [ka]

[0278] <Comparative Example 4: Preparation of Thermosetting Resin Composition 11> Thermosetting resin composition 11 was obtained in the same manner as in Example 1, except that three parts of aliphatic bifunctional epoxy resin (ADEKA "ED-506", epoxy equivalent of approximately 300, structure represented by the following formula (A'-3) (wherein l is the number satisfying an epoxy equivalent of approximately 300 g / eq)) were used instead of three parts of aliphatic monofunctional epoxy resin (Nagase ChemteX "EX-121").

[0279] [ka]

[0280] <Test Example 1: Measurement and Evaluation of Dielectric Loss Tangent> (1) Preparation of hardened material for evaluation A PET film treated with a release agent (Lintec "501010", 50 μm thick, 240 mm square) was placed on a glass cloth-based epoxy resin double-sided copper-clad laminate (Panasonic "R5715ES", 0.7 mm thick, 255 mm square), and the four sides were fixed with polyimide adhesive tape (10 mm wide) (hereinafter also referred to as the "fixed PET film").

[0281] The thermosetting resin compositions 1 to 11 obtained in the examples and comparative examples were applied to the release surface of a fixed PET film using an applicator so that the thickness of the thermosetting resin composition layer after drying was 40 μm, and a thermosetting resin composition layer was formed by drying at 70°C to 100°C (average 100°C) for 3 minutes.

[0282] Next, the thermosetting resin composition layer was heat-cured in an oven at 190°C for 90 minutes. After heat curing, the polyimide adhesive tape was peeled off, the cured material was removed from the glass cloth substrate epoxy resin double-sided copper-clad laminate, and the PET film was also peeled off to obtain a sheet-like cured material. The obtained cured material is referred to as the "evaluation cured material."

[0283] (2) Measurement of dielectric loss tangent (at 25°C and 90°C) For the cured samples used for evaluation, the dielectric loss tangent (Df) was measured at a measurement frequency of 10 GHz using the split-cylinder resonance method with EM Lab's "CR-710". The dielectric loss tangent was measured at 25°C and 90°C.

[0284] (3) Evaluation of the temperature stability of the dielectric loss tangent The percentage increase (%; calculated using the formula below) between the dielectric loss tangent Df(25°C) and the dielectric loss tangent Df(90°C) at 90°C was determined. If this Df increase rate was less than 35%, the temperature stability of the dielectric loss tangent was good, and it was judged as "○". If this Df increase rate was 35% or more, the temperature stability of the dielectric loss tangent was poor, and it was judged as "×".

[0285] Df increase rate (%) = (Df(90℃) - Df(25℃)) / Df(25℃) × 100

[0286] <Test Example 2: Measurement of Glass Transition Temperature> The cured material for evaluation was cut into test specimens approximately 5 mm wide and 15 mm long, and thermomechanical analysis was performed using a thermomechanical analyzer (Rigaku Corporation, "Thermo Plus TMA8310") by the tensile loading method. After mounting the test specimens in the apparatus, measurements were taken twice consecutively under measurement conditions of a load of 1 g and a heating rate of 5 °C / min. The glass transition temperature was obtained in the second measurement.

[0287] <Test Example 3: Evaluation of Reflow Resistance> (1) Preparation of resin sheets As a support, we prepared a PET film (Toray Industries' "Lumirror R80," 38 μm thick) that had been treated with an alkyd resin-based release agent (Lintec's "AL-5"). On the support, thermosetting resin compositions 1 to 11 were uniformly applied using a die coater so that the thickness of the thermosetting resin composition layer after drying was 40 μm, and a thermosetting resin composition layer was formed on the support by drying at 70°C to 100°C for 3 minutes. Next, a rough surface of a polypropylene film (Alfan MA-411, manufactured by Oji F-Tex Co., Ltd., 15 μm thick) was laminated as a protective film to the side of the thermosetting resin composition layer that was not bonded to the support. This resulted in a resin sheet having a layer structure of protective film / thermosetting resin composition layer / support.

[0288] (2) Preparation of inner layer substrate As the inner layer substrate, a glass cloth-based epoxy resin double-sided laminate (conductor layer thickness 35 μm, substrate base thickness 0.8 mm, Panasonic "R1515A") was prepared, having conductive layers (copper layers) on both sides with circular degass holes with a diameter of 200 μm formed at a 2 mm pitch. Both sides of this core substrate were etched by 1 μm using a micro-etching agent (MEC "CZ8101") to roughen the copper surface.

[0289] (3) Lamination of resin sheets The protective film was peeled off the resin sheet to expose the thermosetting resin composition layer. Using a batch-type vacuum pressure laminator (Nikko Materials Co., Ltd., 2-stage build-up laminator "CVP700"), the thermosetting resin composition layer was laminated on both sides of the inner layer substrate so that it was in contact with the inner layer substrate. Lamination was performed by reducing the pressure to 13 hPa or less by depressurizing for 30 seconds, and then pressing at 120°C and a pressure of 0.74 MPa for 30 seconds. Subsequently, the layers were heat-pressed at 100°C and a pressure of 0.5 MPa for 60 seconds to smooth them out.

[0290] (4) Thermosetting of the thermosetting resin composition layer Subsequently, the inner layer substrate, on which the resin sheets were laminated, was placed in a 130°C oven and heated for 30 minutes, then transferred to a 170°C oven and heated for another 30 minutes to heat-cur the thermosetting resin composition layer and form an insulating layer. After that, the support was peeled off to obtain a cured substrate A having a layer structure of insulating layer / inner layer substrate / insulating layer.

[0291] (5) Roughening treatment A desmear treatment was performed on the cured substrate A as a roughening treatment. The following wet desmear treatment was carried out.

[0292] (Wet desmear treatment) The cured substrate A was immersed in a swelling solution (Atotec Japan's "Swelling Dip Securigant P," an aqueous solution of diethylene glycol monobutyl ether and sodium hydroxide) at 60°C for 5 minutes, then immersed in an oxidizing agent solution (Atotec Japan's "Concentrate Compact CP," an aqueous solution of potassium permanganate at approximately 6% and sodium hydroxide at approximately 4%) at 80°C for 15 minutes, then immersed in a neutralizing solution (Atotec Japan's "Reduction Solution Securigant P," an aqueous sulfuric acid solution) at 40°C for 5 minutes, and finally dried at 80°C for 15 minutes.

[0293] (6) Formation of the conductive layer A conductive layer was formed on the roughened surface of the insulating layer according to a semi-additive method. Specifically, the roughened substrate was immersed in an electroless plating solution containing PdCl2 at 40°C for 5 minutes, and then immersed in an electroless copper plating solution at 25°C for 20 minutes. Next, it was annealed by heating at 150°C for 30 minutes, after which an etching resist was formed and a pattern was formed by etching. Subsequently, copper sulfate electroplating was performed to form a conductive layer with a thickness of 25 μm, and annealing was performed at 180°C for 30 minutes. The resulting substrate is referred to as evaluation substrate B.

[0294] (7) Evaluation of reflow resistance Evaluation board B was cut to obtain small pieces measuring 100 mm x 50 mm. These pieces were tested by passing them through a reflow soldering machine (HAS-6116, manufactured by Nippon Antom Co., Ltd.) that reproduced a peak reflow temperature of 260°C five times (the reflow temperature profile conformed to IPC / JEDEC J-STD-020C). This test was performed on five pieces, and the pieces were visually inspected after testing. Based on the visual inspection, if three or more pieces showed abnormalities such as blistering in the conductor layer, the reflow resistance was judged as poor and marked with "×". If one or two pieces showed abnormalities such as blistering in the conductor layer, the reflow resistance was judged as within an acceptable range and marked with "△". Furthermore, if all pieces showed no abnormalities at all, the reflow resistance was judged as good and marked with "○".

[0295] The results for Examples 1-8 and Comparative Examples 1-4 are shown in Table 1.

[0296] [Table 1]

[0297] Furthermore, it has been confirmed that when the content of component (A) in the thermosetting resin composition exceeds 25% by mass, when the total resin component in the thermosetting resin composition is taken as 100% by mass, the glass transition temperature of the resulting cured product (insulating layer) tends to decrease, resulting in poor heat resistance or poor reflow resistance (evaluation ×).

Claims

1. A thermosetting resin composition comprising (A) a monofunctional epoxy resin represented by the following formula (1), (A') an epoxy resin other than component (A), and (B) a radical polymerizable compound, 【Chemistry 1】 (In equation (1), R is expressed by equation (2) below.) 【Chemistry 2】 (Equation (2) satisfies any of the following conditions (a) to (e). (i) R １ R represents a branched alkyl group having 3 to 8 carbon atoms, which may have substituents. ３ Here, x represents an alkylene group having 1 to 6 carbon atoms, which may have substituents; x represents -O-; n1 represents 0; n2 represents 1; and n3 represents 1. (b) Caution １ R represents a linear alkyl group having 3 to 20 carbon atoms, which may have substituents. ３ Here, x represents an alkylene group having 1 to 6 carbon atoms, which may have substituents; x represents -O-; n1 represents 0; n2 represents 1; and n3 represents 1. (h) R １ n1 represents an alkyl group having 3 to 20 carbon atoms, which may have substituents, n2 represents 0, and n3 represents 0. (ii) R １ R represents an alkyl group having 3 to 20 carbon atoms, which may have substituents. ２ R represents an alkylene group having 1 to 6 carbon atoms, which may have substituents. ３ Here, x represents an alkylene group having 1 to 6 carbon atoms, which may have substituents; X represents -O-; n1 represents a number between 1 and 50; n2 represents 1; and n3 represents 1. (h) R １ represents an alkyl group having 3 to 20 carbon atoms which may have a substituent, R ３ represents an alkylene group having 1 to 6 carbon atoms which may have a substituent, X represents -C(=O)-O-, n1 represents 0, n2 represents 1, and n3 represents 1. Here, the substituent is one or more selected from halogen atoms, alkenyl groups having 2 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, and alkenyloxy groups having 2 to 6 carbon atoms. When the resin component in the thermosetting resin composition is considered to be 100% by mass, the content of component (A) is 0.5 to 20% by mass. Component (A') has two or more epoxy groups in one molecule, Component (B) contains multiple allyl groups and multiple benzene rings, The radical polymerizable unsaturated group equivalent of component (B) is 250 g / eq. to 1200 g / eq. A thermosetting resin composition in which the mass ratio of component (A) to component (B) (component (A) / component (B)) is 0.01 or more and 0.6 or less.

2. A thermosetting resin composition comprising (A) a monofunctional epoxy resin represented by the following formula (1), (A') an epoxy resin other than component (A), and (B) a radical polymerizable compound, 【Transformation 3】 (In equation (1), R is expressed by equation (2) below.) 【Chemistry 4】 (Equation (2) satisfies any of the following conditions (a) to (d). (i) R １ R represents a branched alkyl group having 3 to 8 carbon atoms, which may have substituents. ３ Here, x represents an alkylene group having 1 to 6 carbon atoms, which may have substituents; x represents -O-; n1 represents 0; n2 represents 1; and n3 represents 1. (b) Caution １ R represents a linear alkyl group having 3 to 20 carbon atoms, which may have substituents. ３ Here, x represents an alkylene group having 1 to 6 carbon atoms, which may have substituents; x represents -O-; n1 represents 0; n2 represents 1; and n3 represents 1. (h) R １ n1 represents an alkyl group having 3 to 20 carbon atoms, which may have substituents, n2 represents 0, and n3 represents 0. (ii) R １ R represents an alkyl group having 3 to 20 carbon atoms, which may have substituents. ２ R represents an alkylene group having 1 to 6 carbon atoms, which may have substituents. ３ Here, x represents an alkylene group having 1 to 6 carbon atoms, which may have substituents; X represents -O-; n1 represents a number between 1 and 30; n2 represents 1; and n3 represents 1. Here, the substituent is one or more selected from halogen atoms, alkenyl groups having 2 to 6 carbon atoms, alkoxy groups having 1 to 6 carbon atoms, and alkenyloxy groups having 2 to 6 carbon atoms. When the resin component in the thermosetting resin composition is considered to be 100% by mass, the content of component (A) is 0.5 to 20% by mass. Component (A') has two or more epoxy groups in one molecule, Component (B) is at least one selected from the group consisting of compounds containing multiple allyl groups and benzene rings, with a radical polymerizable unsaturated group equivalent of 250 g / eq. to 1200 g / eq., and compounds containing a group represented by the following formula (B1). 【Transformation 5】 (In equation (B1), R Ａ１ , R Ａ２ and R Ａ３ Each of these independently represents either a hydrogen atom or an alkyl group; R Ａ４ Each of these independently represents an alkyl group; m ａ１ represents 0 or 1; m ａ２ (where represents an integer from 0 to 4; and * represents a combination.) A thermosetting resin composition in which the mass ratio of component (A) to component (B) (component (A) / component (B)) is 0.01 or more and 1 or less.

3. The thermosetting resin composition according to claim 1, further comprising (E) an inorganic filler.

4. The thermosetting resin composition according to claim 1, wherein, when the resin component in the thermosetting resin composition is considered to be 100% by mass, the content of component (B) is 1 to 70% by mass.

5. The thermosetting resin composition according to claim 3, wherein, when the nonvolatile components in the thermosetting resin composition are taken as 100% by mass, the content of component (E) is 40% by mass or more.

6. A thermosetting resin composition according to claim 1, for use as an insulating layer for a circuit board.

7. A resin sheet comprising a support and a layer of a thermosetting resin composition according to any one of claims 1 to 6 provided on the support.

8. The resin sheet according to claim 7, wherein the support is a thermoplastic resin film or a metal foil.

9. A cured product of the thermosetting resin composition according to any one of claims 1 to 6.

10. A circuit board comprising an insulating layer made of a cured product of a thermosetting resin composition according to any one of claims 1 to 6.

11. A semiconductor device comprising the circuit board described in claim 10.

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