Effects of intermetallic compound layer thickness on the mechanical properties of silicon-copper interface

Abstract

Intermetallic compounds (IMC) are found in the dual-layer composite, such as Si/Cu composite in multilayer semiconductor structures, and are often ignored in simulations that aim to predict the mechanical properties. The interface model of Si/Cu composites with different thickness of IMC layer is first established by molecular dynamics simulation. Then this study analyzed the elastoplastic behavior and adhesion behavior of the Si/Cu interface and the effect of IMC on the fracture properties. The simulation results demonstrate that the Si/Cu interface fails in a quasi-brittle fracture mode. The crack propagates along the interface between Si and the IMC layer. An apparent dislocation emission and large plastic deformation are found exclusively in the Cu layer. The thickness of the IMC layer increased from 2 to 10 Å, and the critical strain energy release rate increased from 14.48 J/m2 to 19.76 J/m2, while the equivalent modulus is not increase monotonically. Therefore, the IMC is of high significance for predicting the mechanical properties of the dual-layer composite.