In-line process monitoring using micro-raman spectroscopy

Abstract

An in-line non-destructive method is described for identifying phases in a micro-structure such as a fine line pattern. This is accomplished by observing the Raman spectrum of the micro-structure. A particular application is a silicide layer, prepared using the SALICIDE process, where the crystal phases before and after Rapid Thermal Anneal are often different. This is reflected by the appearance of different lines in the Raman spectra so that the fraction of each phase can be determined. If the silicide layer agglomerated during the anneal, this is also detected by the Raman spectrum. The method has been used successfully down to line widths of about 0.35 microns.