- SEMI MF1530 - Test Method for Measuring Flatness, Thickness, and Total Thickness Variation on Silicon Wafers by Automated Noncontact Scanning
This Standard was technically approved by the Silicon Wafer Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on August 17, 2018. Available at www.semiviews.org and www.semi.org in October 2018; originally published by ASTM International as ASTMvF1530-94; previously published May 2012.
Flatness, thickness and thickness variation are vital factors affecting the yield of semiconductor device processing.
Knowledge of these characteristics can help the producer and consumer determine if the dimensional characteristics of a specimen wafer satisfy given geometrical requirements.
This Test Method is suitable for measuring the flatness and thickness of wafers used in semiconductor device processing in the as-sliced, lapped, etched, polished, epitaxial or other layer condition.
This Test Method covers a noncontacting, nondestructive procedure to determine the thickness and flatness of clean, dry, semiconductor wafers in such a way that no physical reference is required.
This Test Method is applicable to wafers 50 mm or larger in diameter, and 100 µm (0.004 in.) approximately and larger in thickness, independent of thickness variation and surface finish, and of wafer shape.
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.
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.
The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
Referenced SEMI Standards
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M20 — Practice for Establishing a Wafer Coordinate System
SEMI M59 — Terminology for Silicon Technology
SEMI MF1390 — Test Method for Measuring Warp on Silicon Wafers by Automated Noncontact Scanning