Photoresist shrinkage is an important systematic uncertainty source in critical dimension-scanning electron microscope
(CD-SEM) metrology of lithographic features. In terms of metrology gauge metrics, it influences both the precision and
the accuracy of CD-SEM measurements, while locally damaging the sample. Minimization or elimination of shrinkage is
desirable, yet elusive. Because this error source will furthermore be a factor in CD-SEM metrology on polymer
materials, learning to work around this issue is necessary.
Tool-to-tool matching is another important component of measurement uncertainty that metrologists must control in
high volume manufacturing, and photoresist samples are a most difficult case due to shrinkage effects, as tool-to-tool
biases can vary based on the sample or other parameters. In this work, we explore different shrinkage effects and their
influence on matching. This will include an investigation of how the photoresist shrinkage rate varies with time from the
chemical development of the photoresists, which necessitates that measurements on different tools within a group be
performed in rapid succession to avoid additional error. The differences in shrinkage rates between static and dynamic
load/unload cases will also be addressed, as these effects also influence matching. The results of these dynamic effect
experiments will be shown to have far-reaching implications for the shrinkage phenomenon in general. Finally, various
sampling schemes for matching will be explored, through both simulation and experiment, for use with shrinking
materials. Included is a method whereby various fleet tools measure different locations, once per tool, within a uniform
line/space grating. Finally, we will assess how well matching can be achieved using these techniques.