NOTICE:
This Document was reapproved with minor editorial changes.
SEMI
M1 specifies the contour of the shaped edge of silicon wafers by using
templates that allow a wide variation in wafer edge profiles manufactured by
silicon suppliers to still meet the specification.
In
many advanced wafer applications, a much tighter specification of the edge
profile is required to control variations in subsequent circuit processing.
These specifications frequently include values for certain characteristics that
describe the segments of the edge profile contour.
A
prerequisite for specifying tighter tolerances on edge profiles is an agreement
about the names of the relevant characteristics used for describing edge
profiles and a method for extracting these characteristics from a measured edge
profile. Therefore in these test methods, terms used to describe the
characteristics of the edge profile of silicon wafers are named and their
meaning is illustrated by a schematic drawing.
This
Standard covers two test methods for deriving these characteristics from a
measured edge profile.
These
test methods are both in use within the industry. They are based on fitting the
measured edge profile over certain segments with straight lines, circular arcs,
or tangent lines to obtain values for profile segment parameters such as:
· bevel angles,
· edge widths,
· apex lengths,
· apex angles,
and
· shoulder
radii.
In addition, the locations of the reference points that
separate the various segments of the edge profile are determined.
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 M76 — Specification for
Developmental 450 mm Diameter Polished Single Crystal Silicon Wafers