Strength evaluation of a selected interface in multi-layered nano-material

A novel notched nano-cantilever specimen consisting of a 1000-nm-thick SiN layer and a 200-nm-thick Cu layer on a Si substrate is proposed to evaluate the strength of a selected interface in multi-layered nano-materials. By introducing a nano-notch near the selected interface, a stress concentration is applied to the interface. The crack is successfully initiated at the Cu/SiN interface by the developed method. Detailed critical stress fields near the edge of Cu/SiN interface for cracking are analyzed by the finite element method, which reveals maximum normal stresses for cracking show good agreement. This indicates the normal stress at concentrated field governs the crack initiation at Cu/SiN interface.