Structural Assessment of (Sub-)Monolayer Coatings in Device Processing at High Spatial Resolving Power by TOF-SIMS Tandem MS Imaging

Whether in discovery research, failure analysis or reverse engineering, the objective is to ascertain the 2D/3D composition and structure of molecules in devices as a result of various processing steps. Most often there is neither sufficient background information nor reference spectra for substantiation of the analytical observations. Two case studies are described here wherein little guidance was provided but accurate and concrete answers were desired. In one case, a carbon residue was observed by Auger electron spectroscopic (AES) imaging of etched e -beam-patterned structures, but the source of carbon was indeterminate. In a second case, molecules having ligands were patterned by a photolithography method and ostensibly loaded with catalytically active metals. Spatially resolved characterization was performed, but fell short of verifying the presence and structure of the intact metal-organic structures.