Eliminating or reducing Al and other metal surface contamination on silicon wafers is a very critical part of IC processes. Choosing an appropriate measurement technique is important for providing accurate and consistent results. The present application note highlights some important advantages of using SurfaceSIMS.XP (XP = extended profile) to determine surface Al contamination on processed Si wafers.
SurfaceSIMS is an ASTM approved method for measuring Na, Al, K and Fe contamination on silicon substrates (ASTM F 1617). On bare Si wafers, SurfaceSIMS provides very similar results over several measurement decades, comparable to other surface metal contamination measurement techniques such as TOF-SIMS and VPD-based techniques. SurfaceSIMS results are reported as contaminant areal densities (atoms/cm2).