Interfacial Fracture Strength of Micro-Scale Si/Cu Components with Different Free-Edge Shape
The strength against interfacial fracture initiation from a free-edge of Si/Cu micro-components was evaluated. The micro-scale cantilever specimens containing dissimilar interfaces were fabricated with a focused-ion-beam (FIB) technique, and they were loaded with a quantitative nanoindenter holder operated in a transmission electron microscope (TEM). The specimens were successfully fractured along the Si/Cu interface, and the critical loads at fracture were measured. The critical stress distribution near the free-edge was evaluated with the finite element method (FEM). The near-edge stress distributions of 90°/90°-shaped specimens were scattered while those of 135°/135°-shaped specimens were in good agreement despite the difference in specimen dimensions. Such a difference was discussed in terms of the relation between the magnitude of stress singularity and the microstructures of material.