Methods and apparatus for predicting oxygen-induced stacking fault density in wafers

Abstract

Methods and apparatus for predicting the density of oxygen-induced stacking faults (OSF) on a surface of a wafer by measuring the surface roughness before and after a surface damaging process is presented. Such damage can be produced by, but not limited to, a wet sand blast (WSB) process, a dry sand blast (DSB) process, lapping with an abrasive material, surface grinding, and by laser irradiation. The surface roughness resulting from the surface damage is quantified and compared with the pre-damaged surface roughness. The difference between the pre- and post-damaged surface roughness is determined and correlated with oxygen-induced stacking fault density to surface roughness correlation data to obtain the predicted oxygen-induced stacking fault density. An automated computer-assisted wafer OSF density evaluation apparatus is provided comprising a computer-based comparator comprising an electronic OSF correlation database and means for inputting pre- and post-damaged surface roughness data into the computer-based comparator, the comparator adapted to compute a delta surface roughness value, the delta being the difference between the post- and pre-damaged surface roughness data, the comparator adapted to correlate the delta surface roughness value with oxygen-induced stacking fault density to surface roughness correlation data to obtain the predicted oxygen-induced stacking fault density for the wafer.