Patent ID: 7160946

Claim:
A method for improving the cohesive strength of a cured die attach adhesive at elevated temperature in which the die attach adhesive formulation comprises a liquid curable resin or a combination of curable resins, initiator, and filler, comprising adding to the uncured die attach adhesive formulation at ambient temperature an aromatic bismaleimide resin powder having a structure: in which X is selected from the group consisting of which bismaleimide resin powder does not dissolve in the liquid curable resin so that the die attach adhesive formulation remains as a multi-phase system both before and after cure, in which adhesive formulation the bismaleimide resin powder is present in an amount of 3 weight % to 30 weight %, excluding filler; and in which adhesive formulation the weight ratio of bismaleimide resin powder to liquid curable resin is 1:3 to 1:45.