25 August 1987 Process Parameters For Submicron Electron Beam Lithography Of NPR
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NPR (Novolac Positive Resist), a high resolution (0.25 pm) positive electron beam resist, is a blend of a cresol novolac and a polymeric dissolution inhibitor, poly(2- methyl-l-pentene sulfone) (PMPS) which undergoes spontaneous depolymerization during electron irradiation. Stringent control of processing parameters is necessary to obtain optimum resist sensitivity and contrast. The study of the chemistry of NPR has been discussed previously. In this paper we report on the role of processing variables on pattern quality and identify some of the conditions necessary for submicron resolution. The effect of NPR prebake temperature on resist pattern quality was studied and thermal analysis data compiled. The contrast of NPR as a function of the developing mode (dip, pubble, spray) was examined. The influence of electron beam parameters such as beam size and beam defocus on resist line edge quality was looked at extensively. The results and conclusions of these studies are reported in this paper. The application of NPR in trilevel resist systems was carefully evaluated. Excellent submicron resolution capabilities of the resist will be illustrated with scanning electron micrographs. Proximity effects were reduced through the use of "ghosting" techniques and examples of improved linewidth control will be shown.
© (1987) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. Frackoviak, J. Frackoviak, R. G. Tarascon, R. G. Tarascon, S. Vaidya, S. Vaidya, E. Reichmanis, E. Reichmanis, "Process Parameters For Submicron Electron Beam Lithography Of NPR", Proc. SPIE 0771, Advances in Resist Technology and Processing IV, (25 August 1987); doi: 10.1117/12.940316; https://doi.org/10.1117/12.940316

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