Comparative ion yields by secondary ion mass spectrometry from microelectronic films

Abstract

Secondary ion mass spectrometry (SIMS) is reported from multiple-element multiple-matrix ion implants. The implants include a thirteen element metal set and a six element gas set implanted into films of interest for microelectronics (silicon, silicides, wiring layers, liner metals, inorganic dielectrics, and polymer dielectrics.) Using these standards, this study performs a broad comparison of ion yields using a metric defined as the normalized useful yield. We find that the yield of K+ with O2+ primaries is constant for almost all matrices, in keeping with a concept of ion yield saturation. The yield of Cl− with Cs+ primaries approaches a yield saturation limit for titanium but the ion yield falls for materials with higher sputter yields, becoming 3.5× lower from copper. The variations in negative ion yields from matrix to matrix are much larger, with anomalies more pronounced, for weaker-yielding ions, becoming 50× for C− from Ti to Cu. In this article we document sets of ion implants, show some of the SIMS profiles, and note trends in ion yields and implications for SIMS analysis.