1.1 This test method covers a noncontacting, non-destructive procedure to determine the thickness and flatness of clean, dry, semiconductor wafers in such a way that no physical reference is required.

1.2 This test method is applicable to wafers 50 mm or larger in diameter, and 100 [mu]m (0.004 in.) approximately and larger in thickness, independent of thickness variation and surface finish, and of wafer shape.

1.3 This test method measures the flatness of the front wafer surface as it would appear relative to a specified reference plane when the back surface of the water is ideally flat, as when pulled down onto an ideally clean, flat chuck. It does not measure the free-form shape of the wafer.

1.4 Because no chuck is used as a measurement reference, this test method is relatively insensitive to microscopic particles on the back surface of the wafer.

1.5 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.