- SEMI MF1390 - Test Method for Measuring Bow and Warp 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 18, 2018. Available at www.semiviews.org and www.semi.org in February 2018; originally published by ASTM International ASTM F1390-92; previously published October 2014.
Bow and warp can significantly affect 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.
Changes in wafer bow and warp during processing can adversely affect subsequent handling and processing steps. These changes can also provide an important process monitoring function.
This Test Method is suitable for measuring the bow and warp of wafers used in semiconductor device processing in the as-sliced, lapped, etched, polished, epitaxial or other layer condition and for monitoring thermal and mechanical effects on the bow and warp of wafers during device processing.
This Test Method covers a noncontacting, nondestructive procedure to determine the bow and warp of clean, dry semiconductor wafers.
This Test Method employs a two-probe system that examines both external surfaces of the wafer simultaneously.
The Test Method is applicable to wafers 50 mm or larger in diameter, and approximately 100 µm and larger in thickness, independent of thickness variation and surface finish, and of gravitationally induced wafer distortion.
This Test Method is not intended to measure the flatness of either exposed silicon surface. Bow and warp are measures of the distortion of the median surface of the wafer.
This Test Method measures bow and warp of a wafer corrected for mechanical forces applied during the test. Therefore, the procedure described gives the unconstrained value of bow and warp.
This Test Method includes several methods for canceling gravity-induced deflection which could otherwise alter the shape of the wafer.
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 MF1530 — Test Method for Measuring Flatness, Thickness, and Thickness Variation on Silicon Wafers by Automated Noncontact Scanning