Epoxy resin, epoxy resin composition, resin sheet, B-stage sheet, C-stage sheet, cured product, metal foil with resin, metal substrate, and power semiconductor device

1. An epoxy resin composition, comprising:

an epoxy resin comprising a mesogenic structure and a siloxane structure, wherein the mesogenic structure comprises a structure represented by the following Formula (1):

wherein, in Formula (1), X represents a single bond or at least one kind of linking group selected from the following Group (I) consisting of divalent groups; each Y independently represents an aliphatic hydrocarbon group having from 1 to 8 carbon atoms, an aliphatic alkoxy group having from 1 to 8 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, or an acetyl group; each n independently represents an integer from 0 to 4; and * is a linking portion in a molecule;

Group (I) consisting of divalent groups

wherein, in Group (I) consisting of divalent groups, each Y independently represents an aliphatic hydrocarbon group having from 1 to 8 carbon atoms, an aliphatic alkoxy group having from 1 to 8 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, a cyano group, a nitro group, or an acetyl group; each n independently represents an integer from 0 to 4; k represents an integer from 0 to 7; m represents an integer from 0 to 8; and l represents an integer from 0 to 12, and

wherein an epoxy equivalent of the epoxy resin is from 250 g/eq to 2000 g/eq; and

a curing agent comprising a novolac resin including a partial structure represented by at least one selected from the group consisting of the following Formulas (III-1), (III-2), (III-3), and (III-4),

wherein in Formulas (III-1), (III-2), (III-3), and (III-4), each of m31, m32, m33, m34, n31, n32, n33, and n34 independently represents a positive integer, each of Ar 31 , Ar 32 , Ar 33 , and Ar 34 independently represents a group represented by the following Formulas (III-a) or (III-b),

wherein in Formulas (III-a) and (III-b), each of R 31 and R 34 independently represents a hydrogen atom or a hydroxyl group; and each of R 32 and R 33 independently represents a hydrogen atom, or an alkyl group having 1 to 8 carbon atoms.

2. The epoxy resin composition according to claim 1 , further comprising a filler.

3. The epoxy resin composition according to claim 2 , wherein a content of the filler is from 45% by volume to 90% by volume, with respect to the total volume of all solids of the epoxy resin composition.

4. The epoxy resin composition according to claim 1 , wherein the epoxy resin composition is capable of forming a high order structure.

5. A resin sheet, comprising a resin composition layer comprising the epoxy resin composition according to claim 1 .

6. A B-stage sheet, comprising a semi-cured resin composition layer comprising a semi-cured product of the epoxy resin composition according to claim 1 .

7. The B-stage sheet according to claim 6 , wherein the semi-cured resin composition layer comprises a high order structure.

8. A C-stage sheet, comprising a cured resin composition layer comprising a cured product of the epoxy resin composition according to claim 1 .

9. The C-stage sheet according to claim 8 , wherein the cured resin composition layer comprises a high order structure.

10. A cured product of the epoxy resin composition according to claim 1 .

11. The cured product according to claim 10 , wherein the cured product comprises a high order structure.

12. A metal foil with resin, comprising:

a metal foil; and

a semi-cured resin composition layer that is provided on or above the metal foil, and that comprises a semi-cured product of the epoxy resin composition according to claim 1 .

13. A metal substrate, comprising:

a metal support;

a cured resin composition layer that is provided on or above the metal support, and that comprises a cured product of the epoxy resin composition according to claim 1 ; and

a metal foil that is provided on or above the cured resin composition layer.

14. A power semiconductor device, comprising:

a semiconductor module comprising a metal plate, a solder layer and a semiconductor chip in this order;

a heat dissipator; and

a cured resin composition layer that is provided between the metal plate and the heat dissipator, and that comprises a cured product of the epoxy resin composition according to claim 1 .