Operation and Maintenance Manual Model 7AA Wafer Grinder
7 - 26 Version 1.2 - April 18, 1996
WAFER IN SLOT
Wafer in slot detection consists of a proximity sensor mounted
just below the wafer conveyor to detect the presence or
absence of a wafer during wafer transport. On earlier model
machines the proximity sensor is a convergent fiber optic that
emits light at a skew angle and will reflect the emitted light
when a wafer reaches its focal point. Newer models use a
capacitive sensor which reacts to the change in surrounding
dielectric properties when an object approaches the sensing
area. Adjustment procedures are similar for both types. Both
incorporate an led which will illuminate when the sensor detects
an object.
The characteristics of wafer sensing require that the sensitivity
be adjusted so that wafers are only sensed within a limited
range. This requires that the sensitivity be high enough to
reliably detect a wafer on the conveyor but not high enough to
sense wafers located in the slot above the conveyor.
To Next Page
Loading...