Comparison of sensitivity and exposure latitude for polymethylmethacrylate, UVIII, and calixarene using conventional dip and ultrasonically assisted development

Abstract
Experiments are reported on the characteristics of electron-beam exposed polymethylmethacrylate (PMMA), UVIII, and calixarene resists for ultrasonically assisted development and conventional dip development. Ultrasonically assisted development provides improvements in sensitivity and contrast compared to conventional dip development, for the same development time in the case of 10 μm wide features in PMMA and UVIII, whereas no appreciable change is seen for calixarene. Also, we observe a substantial improvement in exposure dose latitude for smaller linewidths with ultrasonically assisted development compared to dip development for PMMA, UVIII, and calixarene. This improvement decreases somewhat as the linewidth increases. The increases in sensitivity and exposure dose latitude may be significant also in improving ultimate resolution. Isolated lines of 36 nm width have been obtained with UVIII using ultrasonically assisted development.