A COMPARISON OF INTERFACIAL FRACTURE ENERGY OF BONDED WAFERS USING MICRO-INDENTATION AND CRACK PROPAGATION TECHNIQUES

摘要

The interfacial fracture energy, G_(ic), of hydrophilically bonded silicon wafers has been quantitatively measured utilizing a micro-indentation technique based upon a classical Vickers indentation technique. Highly localized measurements of G_(ic) have been made and compared to measurements made using the crack propagation method. These measurements have been performed on specimens of hydrophilic silicon wafers bonded for different anneal temperatures. Annealing for a fixed time at lower temperatures resulted in a markedly lower interfacial fracture energy than for the same time at higher temperatures. The results indicate that physically-based process development maps may be envisaged that relate the kinetics of mass diffusion in silicon to the resulting changes in fracture energy of the interface between bonded wafers. Furthermore, the results of the micro-indentation technique compared with crack propagation measurement show that crack propagation can be an unreliable measurement for samples that have been annealed at high temperatures (T>900℃). However, micro-indentation measurements confirmed that the samples had interfacial energies similar to those of covalently bonded silicon.