ULTRA HIGH RESOLUTION LITHOGRAPHIC IMAGING AND PRINTING AND DEFECT REDUCTION BY EXPOSURE NEAR THE CRITICAL CONDITION

Abstract

Ultra-High Resolution Lithographic Imaging and Printing refers to the reduction in printed feature size, or "demagnification" obtained by the use of "bias". We give a new meaning to Next Generation Lithography. We make use of modern control in the development of resists. We show that by applying classical Fresnel diffraction, mask pattern features are "demagnified" by "bias". We use "bias" to advantage so that: i) mask-wafer gaps; and ii) mask features are enlarged for a given printed feature size. iii) The technique is extensible to beyond 25 nm feature sizes; and iv) exposure times are reduced. The invention is specifically demonstrated in proximity X-ray lithography but has generic extension to all lithographies that can use out of focus imaging. In consequence of the diffraction, printing defects due to mask faults are reduced. Moreover the exposure doses from mask features of various sizes are controlled by various techniques.