200 MM WAFER CARRIER INTERFACE
4
INSTALLATION AND USE MANUAL
ENTEGRIS, INC.
Wafer Plane
This section provides an explanation of the
wafer plane concept and discusses the benefits
of an improved wafer plane. Carriers that hold
each wafer in a predictable location perform
better on automated wafer transfer equipment.
A carrier that does not hold wafers in a predictable
location can cause numerous robotics and wafer
transfer problems. To reduce these problems,
Entegris continually strives to improve wafer
plane dimensions.
Specification Purpose
The wafer plane specification provides the specific,
predictable location of each wafer in a carrier.
Benefits
The benefits of an improved wafer plane include:
• Reduced equipment adjustments
• Improved accuracy in wafer transfers
• Minimized missed wafer transfers
• Reduced equipment shut downs
• Minimized damage or breakage of wafers
• Reduced particle generation caused by wafers
rubbing on carriers
General Definitions
The following definitions define and clarify the
wafer plane concept:
Wafer plane
The position of the wafer in a carrier.
Wafer plane
zone
The acceptable position for a wafer,
defined by the offset dimension and
tolerance.
Pocket center
plane
The imaginary plane that exactly
bisects each pocket.
Wafer seated
surface
The bottom of the wafer, typically the
unfinished side of a wafer in process.
All dimensional data is derived from
this surface.
Offset
dimension
The distance from the pocket center
plane to the bottom, or seated surface
of the wafer.
Datum A
The flat surface defined by the “H” bar
end of a wafer carrier. Datum A can be
established by placing the carrier “H”
bar end down on a flat surface.
Datum B
The flat surface defined by the bottom,
or track of the carrier. Datum B can be
established by placing the carrier track
end down on a flat surface.
