Photoelastic stress evaluation and defect monitoring in 300-mm-wafer manufacturing

Abstract Process monitoring and tool characterization on product wafers require rapid non-contact and non-destructive evaluation methods. Because all process steps are more or less related to stress in the crystal, the photoelastic stress evaluation by infrared polarimetry is a suitable method for process screening both in wafer and IC manufacturing. It is shown that the full wafer imaging by scanning infrared depolarization can be applied to different steps of wafer manufacturing. After a short introduction into the method and technical realization of on-line photoelastic measurements, the concept of defect-related stress monitoring and process screening is demonstrated for slicing, grinding, lapping, etching, polishing and thermal treatment.