In order to investigate delamination crack initiation from an interfacial edge in nanoscale component with the singular stress field, we conduct mechanical experiments using four kinds of cantilever specimens with the nanoscale singular stress field at the copper/silicon nitride interface. The results reveal that regardless of the specimen dimensions, the critical magnitude of the plastic stress intensity parameter, K-interface (edge (c)), is constant (112 MPa m(0.179)) within the singular stress field range of approximately 25 nm. This indicates that in the nano-sized component, a delamination crack initiation is dominated by a nanoscale singular stress field near the interface edge. (C) 2014 Elsevier Ltd. All rights reserved.