There
are several different sampling plans to effectively characterize the
CMP process at hand with varying degrees of quality and efficiency.
Generally, we recommend that first sampling plan (manual plan) with
one die to any customer who performs the measurements manually.
For those using automated tools with pattern recognition capability,
we recommend the second sampling plan (efficient plan). We have
found that this plan provides the best trade-off between quality and
efficiency (time and cost) to our customers.
The high quality plan is largely for those interested in very detailed
analysis including modeling work.
Since
there are many features to measure for this plan, it is highly recommended
that an automated measurement tool be used. In addition, take care
to note the limitations of the tool being used, e.g. the tip size
of a profilometer.
