有限要素法を用いたパワー半導体ダイアタッチ接合部のパワーサイクル破壊進行の再現手法開発

抄録

The study proposed an FEM simulation to reproduce the fatigue crack network failure where cracks occur randomly and repeatedly under a uniform equibiaxial stress field. In this method, randomly occurring cracks are assumed to be deviations following a normal distribution, and crack initiation cycles are calculated with the crack initiation resistance set on the FEM elements using normally distributed random numbers. A fatigue crack growth law is then applied to the cracked element to simulate damage development. The proposed method reproduced the logistic curve-type damage development behavior that are characteristic of fatigue crack network failure. Furthermore, the proposed method is applicable to crack propagation damage from the periphery of die-attach joints and damage in power cycling tests with temperature distribution, and provides a basis for establishing a fatigue life prediction method for die-attach joints.