Maintenance Model 6DS-SP Planarizer
4 - 10 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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