Figure 1 .

Polarizing microscopic images of etched wafers. Micrographs (a) and (b) were obtained from the samples etched in the etchant with IPA ratios of 0 % and 50 %, respectively. In micrograph (a), region E is a well-etched region, whereas etching reaction rarely occurred in region N. An enlarged image of the marked region is illustrated in the inset.