SEMI M17 - Guide for a Universal Wafer Grid
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 31, 2015. Available at www.semiviews.org and www.semi.org in October 2015; originally published in 1990; previously published November 2010.
Maximum allowable slip and other non-uniformly distributed defects are frequently specified when procuring polished and epitaxial silicon wafers. SEMI M62 specifies a maximum allowable fraction of the epitaxial wafer surface area that can contain slip.
This Guide provides a design for and guidance for use of a wafer grid that facilitates the determination of the fraction of the wafer surface area covered by observed defects.
This Document defines a grid pattern that is useful for quantifying surface defects on a nominally circular semiconductor wafer. The grid is defined such that it contains 1000 elements of approximately equal area. Each grid element thus contains 0.1% of the total quality area of the surface being inspected. Defects that are non-uniformly distributed (e.g., slip) can be quantified in terms of the percent defective (or percent useful) area on the wafer surface.
The grid described is referenced to the center of the wafer. A concept of a ‘fixed quality area’ is used, based on nominal wafer diameter, such as is specified in SEMI M1.
Methods for observing these defects on silicon wafer surfaces are outside the scope of this Guide. Such methods may be found in SEMI MF1725, SEMI MF1726, JIS H 0609, and DIN 50434.
Referenced SEMI Standards
SEMI M1 — Specification for Polished Single Crystal Silicon Wafers
SEMI M59 — Terminology for Silicon Technology
SEMI M62 — Specifications for Silicon Epitaxial Wafers
SEMI MF154 — Guide for Identification of Structures and Contaminants Seen on Specular Silicon Surfaces
SEMI MF1725 — Practice for Analysis of Crystallographic Perfection of Silicon Ingots
SEMI MF1726 — Practice for Analysis of Crystallographic Perfection of Silicon Wafers
SEMI MF1809 — Guide for Selection and Use of Etching Solutions to Delineate Structural Defects in Silicon