Latent catalyst for epoxy resin, epoxy resin composition, and semiconductor device

A process for preparing a latent catalyst for epoxy resin, comprising:

• a cation moiety having an activity of accelerating curing reaction of epoxy resin;
• and
• a silicate anion moiety having an activity of suppressing the curing reaction-accelerating activity;
• said process comprising contacting a phosphonium halide with an alkali metal salt of a silicate,
• wherein said latent catalyst is represented by the following formula (1):
• wherein
• A1 represents a phosphorous atom;
• R1, R2, R3 and R4 each represent an organic group having a substituted or unsubstituted, aromatic or heterocyclic ring or represent a substituted or unsubstituted aliphatic group, and R1, R2, R3 and R4 may be the same or different from one another;
• X1 represents an organic group that bonds to Y1 and Y2;
• X2 represents an organic group that bonds to Y3 and Y4;
• Y1 and Y2 each represent a group resulting from a proton-donating substituent through release of a proton, and Y1 and Y2 bond to the silicon atom to form a chelate structure;
• Y3 and Y4 each represent a group resulting from a proton-donating substituent through release of a proton, and Y3 and Y4 bond to the silicon atom to form a chelate structure;
• X1 and X2 may be the same or different from each other;
• Y1, Y2, Y3 and Y4 may be the same or different from one another;
• and
• Z1 represents an organic group having a substituted or unsubstituted, aromatic or heterocyclic ring or represents a substituted or unsubstituted aliphatic group.