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7.)
Symptom: Dot
skipping
Cause
a): The
inker Z-height is set too high. A consistent pattern of skipping dots
often indicates improper Z-height adjustment.
Solution a): Lower
the inker Z-height to a setting that yields round dots without any
skipping.
Related Information: See Inker Set-up Procedure in the inker
Operations
Manual for detailed instructions.
Cause b):
Cartridge was not primed correctly and needs to be
re-primed (filament inkers only).
Solution b): Re-prime
cartridge per instructions on cartridge packaging and run a thousand
dots on a test wafer.
Cause
c): Cartridge
needle tip is damaged.
Solution
c): Replace the damaged cartridge with a new one.
Cause
d): The
cartridge needle is clogged with a debris particle (pneumatic inkers only).
Solution
d): Replace the suspect cartridge with a new one. Return
the suspect cartridge to Xandex for test confirmation and possible
warranty replacement.
Cause
e): Air
bubble (pneumatic inkers only). Small air bubbles are sometimes
present during the first 1,000 dots after initial cartridge priming.
Solution
e): Run
1,000 dots onto a test wafer. This should eliminate any bubbles that may
have been present inside of the cartridge.
Cause
f): Inking surface is not planar.
This can be caused by variations in wafer thickness or if the prober
head plate or chuck is tilted slightly relative to perfect horizontal.
If the dot skipping only occurs on one side of the wafer, it is most
likely due to planarity problems.
Solution
f): Check
the planarity of the prober head plate and chuck. Make planarity
adjustments per the prober manufacturers recommended procedure.
Cause
g): Prober Z stage equipment
problem. The stage Z drive assembly photocells may be defective or
contaminated with dust (if prober is so equipped). Z stage malfunction
can cause the amount of stage travel in the z direction to be
non-uniform, resulting in skipped dots.
Solution
g): Refer
to prober manufacturers recommended verification procedure to insure
correct operation of the prober Z stage drive and clean, adjust or
replace components as necessary.
Cause
h): Inker
equipment problem (pneumatic inkers only). Pneumatic inker
shuttle is clogged with dried ink or other debris, or has been used
outside the recommended shuttle preventive maintenance period causing
inconsistent shuttle motion.
Solution h): Perform recommended preventive
maintenance on the shuttle using the appropriate
shuttle
maintenance kit (available from Xandex). Replacement of the
shuttle may be required if shuttle has been damaged due to a lack of
regular preventive maintenance.
Cause
i): Inker
equipment problem (pneumatic inkers only). Pneumatic
controller has not received regular preventive maintenance, resulting in
inconsistent shuttle and/or cartridge actuator valve performance.
Solution i): Perform recommended preventive
maintenance on the controller using the appropriate
controller
maintenance kit (available from Xandex).
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