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

• The strength of selected interface in the multi-layered nano-material is studied.
• A stress concentration is applied to selected interface by introducing a nano-notch.
• Crack is successfully initiated at the Cu/SiN interface by the developed method.
• The maximum normal stress for cracking shows good agreement for all specimens.
• Normal stress at the concentrated field governs crack initiation at Cu/SiN interface.

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.