Defect identification by compositional defect review using auger electron spectroscopy

Defect identification plays an enabling role in determining the source of particles that occur during semiconductor processing and are subsequently detected by defect inspection tools. Auger electron spectroscopy provides a high spatial resolution, surface sensitive analytical probe that is well matched to examining small, thin or complex defects. A focused ion beam (FIB) can be used to cross-section buried defects and structures for subsequent Auger analysis. Such measurements have been made on defects from two wafers pulled at different process steps. One wafer was analyzed after poly-Si deposition, and the other wafer was analyzed after metal 2 etch. The defects on the poly-Si wafer are Si particles. Three types of particles were found on the metal 2 wafer: C-based, stainless steel, and Si-oxide. The majority of defects on this wafer are C-based. Auger, EDS and FIB results will be compared for representative defects on these two wafers.