Mechanical property characterization of cu-Sn-In intermetallic thin films using microcantilevers

Young's modulus, residual stress and fracture strength of Cu-Sn-In intermetallic thin films are characterized using deflection of microcantilevers and beam mechanics. It is shown through finite element modelling and experiments that deflection of the beams at multiple locations allows correction for non-ideality of the beams originating from the undercut, anticlastic curvature and stress gradient. This method has the advantage over common indentation-based approaches, in that with a single sample we can simultaneously extract the Young's modulus, residual stress and fracture strength of the film. Additionally, knowledge of the Poisson's ratio is not required for the calculation of the Young's modulus.