Strasbaugh nTellect 7AF - Page 536

Strasbaugh nTellect (Model 7AF) Wafer Grinder
14 - 22 Version 1.2 - June 2004
LOAD CELL
COARSE Z LOAD CELL
Cause:
• Reading is out of range.
• Spindle is against hard stop.
• Counterbalance is seriously out of
adjustment.
• One of the two load cells is defective.
Resolution:
• Check position of spindle.
• Move spindle off hard stop.
• Check counterbalance pressure
(between 25-40 psi required).
• Check load cell wiring.
• Replace load cell.
FINE Z LOAD CELL
Cause:
• Reading is out of range.
• Spindle is against hard stop.
• Counterbalance is seriously out of
adjustment.
• One of the two load cells is defective.
Resolution:
• Check position of spindle.
• Move spindle off hard stop.
• Check counterbalance pressure
(between 25-40 psi required).
• Check load cell wiring.
• Replace load cell.
PREALIGNER
PREALIGNER ERROR
Cause:
• Wafer flat/notch not visible.
• Contaminants in optical path.
• Prealigner not homed.
• Vacuum dropout.
• Incorrect vacuum sensor adjustment.
Resolution:
• Clear wafers; check flat/notch on
wafers.
• Clean optical CCD chip.
• Home prealigner.
• Ensure stable vacuum.
• Adjust vacuum sensor.