Operations Model 6DS-SP Planarizer
2 - 26 Version 4.0 - February 1998
When the elevator access door is closed, the elevator automatic fill and
drain valve feature automatically keeps the elevator tanks filled with water
whenever cassettes are present on the elevators. If an elevator arm is lifted,
its tank will begin draining. The drain valve will remain open as long as the
arm is lifted. If the elevator had been filling, the fill valve will now close.
Any raising or lowering of cassette arms for the purpose of controlling
fill/dump valves is ignored when the elevator access door is open. Only
when the door is closed will the arm switches be monitored to control the
valves. This feature is mainly intended to permit removal of polished wafers
from a receive cassette without disturbing the elevator tank fill/dump valves.
If an elevator arm is lowered and the elevator access door is closed, the
elevator’s tank will fill for the time period entered for calibration variable
179. If more than one arm is lowered, the tanks will be filled one at a time.
The first arm lowered always determines the first tank to fill. If additional
arms are then lowered, the following filling priority is used:
1. Active receive cassette's tank (it will be the first to receive
wafers).
2. Active send cassette's tank (if in "dunk send" mode).
3. Inactive send cassette's tank (if in "dunk send" mode).
4. Inactive receive cassette's tank (it will be the last to receive
wafers).
If the "dunk send" (calibration variable 180) mode is not enabled, the send
cassette tanks will never be filled. If the machine is not equipped with
automatic fill and drain valves, the fill time entered for calibration variable
179 will have no effect.
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