Method of making direct bonded wafers having a void free interface

摘要

Wafers which are direct bonded to each other in accordance with prior art processes suffer from voids at their bonded interface. Annealing such composite structures at high temperature and high pressure (for silicon wafers preferably about 1,100 DEG C. and 15,000 psi) eliminates all voids which are not a result of the presence of a particle on one of the wafers at the time of mating.