Operation and Maintenance Manual Model 7AF Wafer Grinder
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Number: 98 Value: 0.0 Label: Vacuum Delays 0=No
With software version 5.00 three optional delays are introduced to help in
wafer handling.
It is possible to postpone lifting the wafer from the work chucks or spin
station, allowing the blowoff to begin and assist the lift.
It is possible to postpone turning off the vacuum at the work chucks or spin
station until the robot has moved over the wafer.
It is possible to extend the duration of the blowoff.
This variable can specify delays 2 and 3. The value zero requests NO delay.
See the release notes for software version 5.00. (Delay 1 is set in the robot
controller. See the end of this section.)
Number: 99 Value: 0.0 Label: Chuck D.I. Coolant Timers
If there is an interruption to the work chuck coolant (also called grinding
water or cutting water or D.I. water or de-ionized water) during the grind
cycle or dress cycle, serious damage can occur to the chuck, the grind wheel,
and to the wafer on the chuck. This will happen quickly. Machine variable
99 allows you to specify the amount of time the grind, dress, or true will be
allowed to continue during an interruption to the coolant flow.
The first digit tells how many seconds to allow during the approach to the
wafer on the left work chuck. The second digit tells how many seconds to
allow during actual grinding on the left work chuck, beginning from the end
of the approach until the grind wheel lifts up at the end of the grind. The
third and fourth digits give the same information for the right work chuck.
None of these four digits is
allowed to be zero, unless all are zero. Zero will be interpreted to allow 5
seconds in all cases.
If any of these timers is exceeded, the grind or dress or true will be aborted.
However, a momentary interruption that does not exceed the timer value will
be allowed. The recommended value is 3131, allowing three seconds of
interruption during the approach but only one second during the grind.
In addition to the variables above, some of the Station Coordinates Special
Items of the Equipe robot controller have been used as machine variables.
These can be set by Strasbaugh Field Service or by the customer, but setting
them requires a bit more care than setting one of the variables listed above.
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