This Test Method covers measurement of the thickness of silicon wafers, polished or unpolished, and estimation of the variation in thickness across the wafer for both flatted and notched wafers. For flatted wafers of 200 mm diameter or less, a five-point pattern offset from the bisector of the primary flat is used. For notched wafers of 200 mm diameter or more, either a symmetrical five-point or nine-point pattern is used.
 

This Test Method is intended primarily for use with wafers that meet the dimension and tolerance requirements of SEMI M1. However, it can be applied to circular silicon wafers or substrates of any diameter and thickness that can be handled without breaking.
 

This Test Method is suitable for both contact and contactless gaging equipment. Precision statements have been established for each in the case of the five-point method applied to flatted wafers.
 

The values stated in inch-pound units are to be regarded as the standard for measurements on wafers of 3 inch diameter or less while the values in metric units are to be regarded as the standard for measurements on wafers of 100 mm diameter or more.

Referenced SEMI Standards (purchase separately)
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M59 — Terminology for Silicon Technology
SEMI MF1530 — Test Method for Measuring Flatness, Thickness, and Thickness Variation on Silicon Wafers by Automated Noncontact Scanning

Revision History
SEMI MF533-0310 (Reapproved 1023)
SEMI MF533-0310 (Reapproved 0416)
SEMI MF533-0310 (technical revision)
SEMI MF533-1109 (technical revision)
SEMI MF533-0706 (technical revision)
SEMI MF533-02a (first SEMI publication)