Abstract

An ac heterodyne interferometric technique for detecting crystal lattice dislocations and measuring their heights is presented. Preliminary laboratory data indicate the sensitivity of the technique for defect detection to be in the nanometer range. Crystal lattice dislocations in semiconductor wafers (sliplines) can render useless any device through which a dislocation passes. These dislocations are caused by the release of latent stresses in the lattice. The release of these stresses is brought about by the processing of wafers for device fabrication. Detection of the sliplines at an early stage is important to process efficiency.

© 1988 Optical Society of America