Hydrogen silsesquioxane on SOI proximity and microloading effects correction from a single 1D characterization sample

Designs patterned by electron beam lithography without applying process effect correction exhibit overexposed dense features and underexposed sparse features for most practical exposure scenarios. This is typified by the limited exposure latitude of hydrogen silsesquioxane resist on silicon-on-insulator substrates used for silicon photonics, which commonly display very high density features (vertical grating couplers, ring resonators) mixed with very sparse features (inverse tapered waveguides, lone waveguides) in a single pattern. The authors have optimized a proximity effect correction (PEC) based on our analysis of a single 1D process control monitor characterization sample. Our PEC verification sample, which includes electron backscatter and process-related microloading effects, achieved linewidths with an RMS error of +/-5.0 nm for features with pattern densities spanning 1%-67%. Ignoring the pattern density-dependent microloading effect limits the resolvable pattern density span to a smaller range and degrades the linewidth error. (C) 2014 American Vacuum Society.