2000 Volume 49 Issue 4 Pages 420-425
Epoxy resins used for encapsulation of integrated circuit (IC) devices are filled with silica particles to reduce the thermal expansion coefficient and to improve the thermal conductivity. We investigated a method for estimating lifetime of cracking of epoxy resins filled with silica particles near the stress singular point. The flexural strength of the resins was measured by using the 4-point bending test on the notched specimens, and the stress distribution near the notch edges was analyzed by using a finite element method.
The stress distribution curves obtained from both the particulate-filled epoxy resins and the unfilled epoxy resins with various stress singularity factor (λ) intersected one after another at a specific distance from the stress singular point. The specific distance of particulate-filled epoxy resins varied depending on the volume fraction of the added particle, the diameter of the particle and the adhesion strength at the particle-matrix interface. This specific distance was related to the plastic zone size of the matrix resin.
