Quantifying residual and surface carbon using polyencapsulation SIMS

In this experiment we investigated two different techniques for carbon quantification and explored the differences in the measurements of volatile and nonvolatile carbon on the surface of wafers. The first technique, thermal desorption gas chromatography mass spectroscopy (TD-GCMS), quantifies the amount of volatile carbon that was absorbed on the surface of the wafer. The second technique, polyencapsulation SIMS, measures nonvolatile carbon or residual interface carbon that has been left behind after high temperature processing steps. Two sets of duplicate wafers were processed at International SEMATECH, one measured by TD-GCMS and the other set was capped with poly silicon and measured by dynamic SIMS. Both techniques produced similar results for the quantification of carbon, but the accuracy and ability to track the residual interface carbon was best shown by polyencapsulation SIMS. (C) 2004 Published by Elsevier B.V.