THREE-DIMENSIONAL STRESS SINGULARITY FIELD AROUND A VERTEX OF EMBEDDED CHIP IN ELECTRONIC DEVICES USING FEM

摘要

It is well known that a stress singularity occurs at a vertex of joints, when materials with different mechanical and thermal properties are joined. In this paper, the distribution of stress, displacement and the order of stress singularity at the vertex of a chip embedded in an electronic packaging are examined using a three-dimensional FEM with a singular element. The stress singularity at a vertex of chip is investigated first in the cases with and without delamination between the chip and the resin enclosing the chip. Then, the contour of the order of singularity is mapped on the Dundurs' parameter plane. After that, the distribution of displacement and stress for several values of the order of singularity are calculated by solving an eigen equation. In particular, the distributions of stress and displacement considering thermal expansions of joint materials are examined.