Nanoindentating Mechanical Responses and Interfacial Adhesion Strength of Electrochemically Deposited Copper Film

Abstract

The nanomechanical responses and interface adhesion of electrochemically plated copper (Cu) film have been investigated for the evaluation of interconnect reliability. The hardness and elastic modulus of the Cu film were measured by nanoindentation test as about 2.1 and , respectively. A dislocation burst phenomenon was observed and revealed the initiation of plastic deformation of the Cu film. The converted true stress-strain curve provided a stress criterion of for the plastic yielding of the Cu film. Besides, the creep behavior was also analyzed under nanoindentation test and showed a power law expression with a creep stress exponent of about 22. Moreover, the interfacial adhesion strength and delamination behavior between the Cu film and silicon carbide (SiC) etch stop layer have been studied using a four-point bending test. During delamination, cracks irregularly propagated along the interface with blocking by the ductile Cu film. The fracture energy release rate for the delamination of interface was measured as around , affected by SiC deposition condition and testing parameter.