Finite element analysis of plastic-encapsulated Multi-Chip Packages

Abstract

This paper describes a three-dimensional finite element study of the residual stress distribution induced inside two plastic-encapsulated Multi-Chip Packages (MCPs) after post-mold-cure. Both the MCPs studied contained two dies. The effect of the positioning of the two silicon dies within the MCP on the maximum residual stress as well as the warpage of the package was studied. The results show that when the spacing between the two dies is varied, the maximum von mises stress is initially more or less constant for relatively small spacings between the dies. However it increases rapidly beyond a critical value and is the highest when the dies are furthest apart with the die edges flush with the edges of the substrate. A larger die tends to experience higher stresses at its corner and has some influence on the warpage of the package.