0142530-000 AB KLA-Tencor Confidential 3-93
3/13/09
KLA-Tencor P-16+ / P-6 User’s Guide Scan Recipes - Feature Find
Failure Option: Save Search Data, Skip Current Scan, or
Scan at Center 3
The choice of Failure Option depends on the preference of the user and the
purpose of the Feature Find scan. When running a recipe with a Feature Find
scan in a sequence recipe, if the option to Save Search Data is selected, after
the Feature Find fails, it will save the x scan search data in the sequence data
set and proceed to the next measurement site. Although the y search scan is
not saved sequence data set, a diagnostic option can be enabled to save the x
and y search scan for an Oval / Rectangle search pattern to a simple binary file
for failure analysis. Similarly if Skip Current Scan is selected, after the
Feature Find fails, it will skip the current site and proceed to the next site,
without saving the data to the sequence data set. This option is not
recommended since the Failure Option to Save Search Data also skips the
current site and the data is saved for failure analysis. The Scan at Center
failure option is generally used if the Feature Find scan is being used as a
delay mechanism. For example, after the stylus is nulled on the sample
surface, the elevator does not stop all motion. On a nanometer scale, there is
still some small motion of the elevator and isolation table. Feature Find can be
used as a delay before the measurement scan begins to allow the elevator and
isolation table to reach equilibrium. For a 3D scan that will take a long
amount of time, the extra time for the Feature Find scan can help to make a
better looking image.
Scan Offset from Center (µm) 3
The Scan Offset from Center will add the specified offset to the feature that
was found. This can be useful if the feature that you want to scan cannot be
easily found with one of the search types, but there is a nearby feature that can
be easily found, as shown in Figure 3.74. For example, if the user wants to
look at micro-loading effects where a different etch depth will be seen at the
open area near the edge of the array compared to within the array. Two recipes
would be setup with each finding the edge of the array. In one recipe a scan
would be done at the found coordinates and in the second recipe an offset
would be applied so that the scan is performed within the array. In this case it
is difficult or impossible to find a specific line within the array, but easy and
fast to find the first line at the edge of the array.
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