Abstract
In plastic packaged integrated circuit (IC) devices, silicon chips are molded with epoxide resins in which silica particles occupy about 60 to 70% of the volume. Recently, the size of chips mounted in a package has increased rapidly with advances in large-scale integration technology. This trend creates a problem of increased mechanical stress in the package, which sometimes causes cracking in the encapsulation resin under temperature cycling and other conditions. Hence, evaluation of the fracture mechanics properties of these materials has become an important issue in package design.
In this study, fracture toughness of highly silica particulate filled epoxide resins for IC encapsulation was studied using the double torsion (DT) test. The effects of loading condition and specimen geometry on the measurement results were studied to determine a proper test condition. The fracture toughness obtained agreed well with the results of the 3-point bending test. Measurements were also made on the materials with different volume fractions, shapes and size of particles to study the fracture properties of highly filled materials. The fracture toughness increased with increasing volume fraction and with irregularly-shaped particles.
