Asyst Technologies VersaPort 2200, Technical Manual

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Released Rev. C 2000-1252-01 Page 17
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Chapter 2: Theory of Operation
This chapter provides an operational overview of the VersaPort 2200 System. The
VersaPort can be supplied as a platform mounted tool or integrated to a BOLTS interface
frame.
The VersaPort positions the cassette to a fixed plane for a Z-axis-robotic wafer/reticle
handler. Each substrate
is extracted from the cassette, processed, and returned to the
cassette by the Process Tool. The fixed stage position places the center of wafer number
one at 45.97 mm (1.81 inches) above the port plate, which is mounted at the SEMI
standard of 900 mm (35.43 inches) with the BOLTS interface.
The cassette shuttle option moves the port door and attached cassette toward the
Process Tool wafer transfer mechanism. The movement is programmable to a maximum
distance of four-and-one-half inches, to position 200mm wafers at the proper location for
transfer.
A laser-based sensing system on the VersaPort provides precision cassette slot location
and wafer mapping. The laser beam also detects cross-slotted wafers. It senses
protruding wafers (horizontal view) so a built-in wafer seater can reseat them in the
cassette. A vertical view retro-reflective infrared sensor (excessive wafer protrusion
sensor) detects wafers exceeding the maximum protrusion point and will halt VersaPort
movement to prevent wafer damage.
A fan is located in the base to exhaust possible particle contamination from the VersaPort
vertical drive system.
The software and hardware provide integrated self-test and diagnostics. A watchdog
timer and non-volatile memory provide power-failure recovery.
The VersaPort operates on 24vdc (+10%, -5%) supplied by the Process Tool.
Communication is through three RS232 serial connectors or one standard 25-pin parallel
connector.