The Nanoindentation-Induced Cracking of Thin Silicon Chips

摘要

The nanoindentation-induced cracking of silicon chip of finite thickness under the Berkovich indenter is simulated by the plastic-damage model to study the effect of chip thickness on the cracking behaviors. An instability for the growth of crack is observed due to the transition from the radial crack to the through-thickness crack, and both the load at radial crack initiation and the critical load at which the instability occurs decrease with the reduction of chip thickness. The dependence of the crack length (c) on the maximum load (P) is found to follow the classic relation of c~(3/2) (propor. to) P for the radial crack, but this relation breaks down for the through-thickness crack, and turns to a linear relation: c (propor. to) P. The expressions for the dependences of critical load and critical crack length on the thickness are obtained by fracture mechanics analysis, and are in good agreement with the current finite element simulations.