Characterization of Dielectric Etching Processes by X-Ray Photoelectron Spectroscopy Analyses in High Aspect Ratio Contact Holes

X-ray photoelectron spectroscopy (XPS) analyses of high aspect ratio structure etched in SiO2 and organic low dielectric constant materials are presented. Analyses are performed after etching using commercial etching tools and standard processes developed for 0.18 µm design rules. Using electron shadowing by adjacent features, differential charging of insulating features and angle-resolved XPS, it is possible to separate the contributions originating from the sidewalls and bottoms of high aspect ratio contact holes. Correlation between XPS analyses and etch mechanisms are also discussed.