is a failure mechanism wherein a part or parts of the die break away from the die
itself. The damage on the die is referred to as a 'die chip-out'
(see Figure 1).
Die chip-outs are often caused by purely
mechanical means, although some cracks can be propagated by thermo-mechanical stresses
until a fragment chips off the die, resulting in a chip-out.
The die corners are most vulnerable to chipping, since they are
more physically exposed than the edges of the die.
that extend into the
of the die
will obviously make a device
Die chip-outs that are just confined to a small area in the periphery of
the die, on the other hand, will probably not immediately result in
electrical failures, but these can lead to a
chip-outs, being surrounded by microcracks, can serve as
propagation when the device is subjected to thermo-mechanical stresses.
These chip-outs may also have some glassivation damage that allows
moisture and contaminant ingress, leading to
Thus, die chip-outs that do not result in immediate electrical failures
must not be ignored.
A Die Chip-out
chip-outs are often due to
For instance, picking up a die carelessly with a tweezer for
eutectic die attach can result in the tweezer slipping out of position,
chipping the die edge in the process. Manual capping of ceramic packages prior to sealing may also
cause a die chip-out, if the cap or lid hits a corner of the die during
also cause die chipping. Probe needles,
die attach dispense tools,
and the like can inadvertently land on the die with force and chip off a
part of it. Improper set-up can likewise cause
wafer saw blades to induce die edge
Failure Mechanisms; Failure Analysis
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