Photoelastic characterization of Si wafers by scanning infrared polariscope

摘要

A small amount of birefringence caused by the photoelastic effect from residual strains, crystal-defects-induced strains, and process-induced strains in Si wafers has been measured by using an improved version of a scanning infrared polariscope (SIRP). The SIRP presented here has high sensitivity sufficient to detect the small amount of strain induced near the wafer-supporting finger by the wafer weight itself.