Epoxy Resin Composition For Semiconductor Sealing Agents and Epoxy Resin Molding Material

1 . An epoxy resin composition (C) for a sealing semiconductor, comprising an epoxy resin (A); and a core-shell polymer (B) comprising at least one rubber layer, wherein at least 70% of the core-shell polymer (B) is dispersed in the form of primary particles in a resin phase containing the epoxy resin, and the epoxy resin composition (C) contains not more than 30 ppm of an alkali metal ion.

2 . The epoxy resin composition (C) for sealing semiconductor according to claim 1 , wherein the epoxy resin composition (C) contains not more than 100 ppm of an anionic emulsifier.

3 . The epoxy resin composition (C) for sealing semiconductor according to claim 1 , wherein the epoxy resin composition (C) is prepared by mixing an aqueous latex comprising the core-shell polymer (B) comprising at least one rubber layer with an organic solvent (I) to form a mixture (F),

bringing the mixture (F) into contact with water to form aggregates (G) of the core-shell polymer (B) in an aqueous phase (H), the aggregates (G) comprising the organic solvent (I),

parating the aggregates (G) from the aqueous phase (H), and

mixing the aggregates (G) with the epoxy resin (A).

4 . The epoxy resin composition (C) for sealing semiconductor according to claim 1 , wherein the epoxy resin composition (C) is prepared by mixing an aqueous latex comprising the core-shell polymer (B) comprising at least one rubber layer with an organic solvent (I) to form a mixture (F),

bringing the mixture (F) into contact with water to form aggregates (G) of the core-shell polymer (B) in an aqueous phase (H), the aggregates (G) comprising the organic solvent (I),

separating the aggregates (G),

adding an organic solvent (I) to form a dispersion (E) containing the core-shell polymer (B) dispersed in the organic solvent (I), and

mixing the dispersion (E) with the epoxy resin (A).

5 . The epoxy resin composition (C) for sealing semiconductor according to claim 1 , wherein, in preparing the epoxy resin composition (C), before mixing the dispersion (E) with the epoxy resin (A), steps of bringing the dispersion (E) into contact with water and then separating an aqueous phase are performed at least once.

6 . The epoxy resin composition (C) for a sealing semiconductor according to claim 1 , wherein at least 90% of the core-shell polymer (B) is dispersed in the form of primary particles in the resin phase containing the epoxy resin, and the epoxy resin composition (C) contains not more than 15 ppm of the alkali metal ion.

7 . The epoxy resin composition (C) for sealing semiconductor according to claim 6 , wherein the epoxy resin composition (C) contains not more than 60 ppm of an anionic emulsifier.

8 . The epoxy resin composition (C) for sealing semiconductor according to claim 1 , wherein the core-shell polymer (B) is a polymer comprising a multilayer structure comprising at least two layers including at least one crosslinked rubbery polymer layer.

9 . The epoxy resin composition (C) for sealing semiconductor according to claim 8 , wherein the core-shell polymer (B) is a graft copolymer comprising 40 to 95 percent by weight of a rubber particle core (B- 1 ) and 5 to 60 percent by weight of a shell layer (B- 2 ),

the rubber particle core (B- 1 ) comprising an rubber elastomer, an elastic polysiloxane rubber, or a mixture of the rubber elastomer and the elastic polysiloxane rubber,

the rubber elastomer comprising at least 50 percent by weight of at least one monomer selected from a diene monomer and a (meth)acrylate monomer and 50 percent by weight or less of another copolymerizable vinyl monomer,

the shell layer (B- 2 ) comprising a polymer prepared by polymerizing at least one polymerizable vinyl monomer selected from a (meth)acrylate, an aromatic vinyl, vinyl cyanide, an unsaturated acid derivative, a (meth)acrylamide derivative, and a maleimide derivative.

10 . The epoxy resin composition (C) for sealing semiconductor according to claim 9 , wherein the shell layer (B- 2 ) of the core-shell polymer (B) comprises at least one reactive functional group selected from the group consisting of an epoxy group, a carboxyl group, a hydroxyl group, and a carbon-carbon double bond.

11 . The epoxy resin composition (C) for sealing semiconductor according to claim 10 , wherein the reactive functional group contained in the shell polymer (B- 2 ) of the core-shell polymer (B) is an epoxy group, and the epoxy equivalent value is not more than 4,500 for the entire core-shell polymer (B).

12 . The epoxy resin composition (C) for sealing semiconductor according to claim 1 , wherein the epoxy resin (A) comprises not less than 50 percent by weight of at least one epoxy resin selected from a diglycidyl ether of a biphenol or an aromatic nucleus-substituted biphenol or a condensate thereof, a novolac-type epoxy resin, a dicyclopentadienyl-type epoxy resin, and an alicyclic epoxy resin containing a cycloolefin oxide skeleton structure per molecule, for the total amount of epoxy resin (A).

13 . An epoxy resin molding material for a sealing semiconductor, wherein the epoxy resin molding material comprises the epoxy resin composition (C) according to claim 1 , a curing agent (K), an inorganic filler (L), and, if necessary, a curing accelerator (M).