Operations and Maintenance Manual Troubleshooting
Version 1.2 - June 2004 14 - 13
Figure 14-6
5. Chatter Marks on the Wafer Edge
Description: Chatter marks are located around the edge of the wafer and are
generally 1/4 inch in length or less. They are probably caused by a wheel that needs to
be dressed or has not been trued.
Corrective Action: The first step is to dress the fine wheel. If the initial wheel
dressing does not work, dress the wheel a second time. If the second wheel dress
does not work, the problem should be investigated further and resolved. This may be
caused by burrs from tape on the outside edge of the wafer.
Figure 14-7
6. Star Crack
Description: Star cracks are caused by an object between the wafer and the work
chuck surface during the grinding process. The object could be under the protective
tape, stuck to the work chuck, or embedded in the work chuck surface.
Corrective Action: Inspect the wafer and chuck for any foreign objects. If an object
is found between the tape and the wafer, inspect remaining taped wafers for similar
objects. If an object is found stuck to the work chuck, the chuck should be cleaned. If
the object is embedded in the work chuck, the work chuck should be dressed.
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