Analysis of Stress Distribution in Au Micro-Interconnection by Polycrystalline Models

Abstract

A gold (Au) micro-interconnection, which connects through-hole electrodes in a three-dimensional chip-stacking LSI, is composed of several tens of grains. If the size of the interconnection becomes small in comparison with the grain, the anisotropic property of grains influences mechanical reliability. In this study, the stress distribution in the Au micro-interconnection is investigated by finite element method (FEM) analysis. The crystallographic structure of the Au micro-interconnection is obtained by a three-dimensional simulation based on a nucleation and growth model. The FEM analysis shows that the stress is concentrated on the region near the micro-interconnection/substrate interface edge and that a stress singularity exists there. The stress distribution of the micro-interconnection varies because of microscopic factors, which are due to the shape and crystallographic orientation of grains. Statistical evaluations of plural analytical models show that the stress variation approximates a normal distribution.

Evaluation on plastic deformation property of copper nano-film by nano-scale cantilever specimen

“…On the other hand, metals with dimensions less than a micrometer possess plastic deformation properties different from those of the bulk [3][4][5]. Furthermore, since the device components are surrounded by dissimilar materials [6][7], the resulting deformation constraints may affect the plastic behavior. Thus, nano-sized metal components in electronic devices are expected to show specific deformation properties due to both their size and their constraints.…”