R. Howard Strasbaugh, Inc.
July 14, 1995 6DS-SP Ver 4.14 Page 2
Settable Spindle Flush Water and Air Blowoff Times:
Calibration variable 176 "Flush water time (secs)"
Calibration variable 177 "Flush air blowout time (secs)"
Calibration variables 176 and 177 permit setting the times for water and air blowoff
during automatic cycle spindle flushing. These can be used with the existing calibration
variable 173 "Approx flush blowout pres(psi)" to customize flushing for a specific
application. (The forced spindle flush available in the Auto Polish menu does not use
these times and instead uses "hard coded" times for a roughly 1 minute flush cycle.)
Typically the water time should be very short and the air blowoff time much longer. The
original fixed times for the automatic cycle flush were 1 second for water and 12 seconds
for air. To make the machine perform as it did originally, use these values.
Spindle flushing can be tested in the Diagnostics menu by forcing on flag 232 for the left
spindle and flag 233 for the right spindle. During the water flush time, a "slug" of water
will be introduced into the backpressure line. During the subsequent air blowoff time,
that slug of water should be pushed through the line and out the carrier. Once the water is
out of the line and carrier, air will exit carrier pad holes confirming that the line is empty.
Also, the load rinse and, if the second table is installed, the carrier pad rinse will turn on
during the entire flush cycle. Previously they were turned on during the last 2 seconds.
NOTE:
It is important that all water introduced into the lines be thoroughly flushed out.
Otherwise, the weight of a column of water may bear on the backside of the next
wafer or water may drain into the machine's exhaust system.
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