Experimental and theoretical studies of electron beam lithography for the fabrication of semiconductor circuits with submicron dimensions: Water distortion, comparison of results

The fabrication of structures with submicron dimensions by electron beam lithography is described. Accurate delineation is achieved by adjustment of the exposure dose to correct for proximity effects, at least for structures 0.5 micron. Overlay accuracy down to 0.1 micron was demonstrated. Anisotropic dry etching was used for the transfer of submicron resist structures into underlying layer without loss of dimensional control. No plastic wafer distortion could be demonstrated. Elastic wafer distortion resulting from grown or deposited layers can be calculated and may be taken into consideration in mask fabrication. With standard processing wafer distortion is 1 micron per 5 cm distance at the wafer surface.