1993 Volume 42 Issue 472 Pages 40-45
Epoxy resins for encapsulating integrated circuit (IC) devices are filled with silica particles to reduce thermal expansion coefficient and to improve thermal conductivity. Since these particles occupy roughly 60-70% of the total volume, they have a significant effect on the fracture properties of the resins. This study reports the effects of filler particle shape and size on the static strength of smooth specimens and crack propagation of highly silica particulate-filled epoxy resins for IC encapsulation. The smooth specimen strength, fracture toughness and fatigue crack propagation rate were measured, respectively, by the three-point bending test, the double torsion test and the cyclic tensile test of singleedge notched specimens. The effect of particle shape was examined using one type of irregularly shaped and two types of spherical particles.
It was found that large particles lower the static strength, while large and also irregularly shaped particles improve resistance to crack propagation. Although large filler particles cause cracks to originate at the smooth specimen surface, they help to resist crack propagation.
