Enhanced Adhesion and Thermal Conductivity of Epoxy Sealant
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
An increase of 1300% in adhesion (peel strength) of cured epoxy to aluminum is achieved by blending at least 25% by weight of high density, hot pressed boron nitride powder into the liquid epoxy just prior to application. Also, the thermal conductivity of the cured epoxy is increased 800% by this addition of boron nitride. These changes in properties of epoxy are especially beneficial when the material is to be used in packaging of semiconductor device chips. A semiconductor chip solder-bonded to wiring on a ceramic substrate having connecting pins embedded is covered by an aluminum cap which is epoxy-bonded to the substrate edges. The epoxy is applied to the back of the substrate as well as to its edges and is referred to as the "epoxy backseal".