200 MM WAFER CARRIER INTERFACE
ENTEGRIS, INC.
INSTALLATION AND USE MANUAL
5
Specification Description
Wafer plane is defined by an offset dimension and
a tolerance. The offset dimension is called out from
the pocket center plane, a distance calcu lated
from Datum A (“H” bar).
Offset Dimension
The offset dimension is the distance from the
pocket center plane to the center of the wafer
plane zone, toward Datum A. This dimension,
always negative, defines the center of the wafer
plane zone.
Tolerance
The tolerance defines the thickness of the wafer
plane zone.
Calculating Pocket Center Plane Distance
The pocket center plane distance varies for
each specific pocket in a wafer carrier. It can
be calculated with the following formula:
X = D1 + (N - 1)
×
B2
Where:
X = Pocket center plane distance for pocket N
from Datum A
D1 = Distance from Datum A to the center plane
of pocket one
N = Pocket number (pocket one is closest to
Datum A)
B2 = Wafer carrier pitch (pocket spacing)
Calculating Wafer Plane Zone
The pocket center plane distance varies for
each specific pocket in a wafer carrier. It can
be calculated with the following formulas:
Y = X - Tolerance
Z = X - Offset - Tolerance
Where:
Y = Top limit of the wafer plane zone for pocket N
Z = Bottom limit of the wafer plane zone
for pocket N
X = Pocket center plane distance for pocket N
NOTE: The offset value is given as a negative
value. Please use the absolute, or non-negative,
value in the above calculations.
Specification Values
Wafer plane specifications vary between various
wafer carrier series and materials. Typical offset
dimensions range between - 0.9 mm and -1.1 mm
(- 0.04" and - 0.05"). Typical tolerances are
±0.6 mm (0.03"). Please reference the specific
drawings for each wafer carrier for exact
dimensions and tolerances.
Use with Automated Equipment
Automated wafer transfer equipment is pro-
grammed to locate the wafer within the wafer
plane zone. Difficulties can arise when the wafer’s
seated surface is outside this zone. The size of
the zone is also important. As the tolerances are
tightened, the zone becomes smaller and wafer
transfer equipment operates with fewer difficulties.
Pocket center plane
Wafer seated surface
center
place
distance
(X)
Da
tu
m
A
Offset
Ø50.8 mm (2.0”)
Standard Version CS5
Y
Z
+
–
Tolerance
