CPC H01L 29/1608 (2013.01) [G01N 23/207 (2013.01); H01L 21/02529 (2013.01); H01L 22/12 (2013.01)] | 8 Claims |
1. A wafer having a retardation distribution measured with a light having a wavelength of 520 nm,
wherein an average value of the retardation is 38 nm or less,
wherein the wafer comprises a micropipe, and
wherein a density of the micropipe is 1.5/cm2 or less.
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