Determination of the Radiation Efficiency, Contrast and Sensitivity in Electron and Ion Lithography

Knowledge of the solubility rate dependence on exposure dose S(D) gives possibility to estimate the values of the radiation efficiency, sensitivity and contrast characteristics in electron and ion lithography. The idea for interconnection between the sensitivity and the contrast characteristics for an arbitrary combination of resist and developer (i.e. at a given molecular weight, resist density and radiation efficiency of the charged particles) is a base for the sensitivity optimisation in order to achieve the required contrast at chosen development conditions. The contrast parameter value y_s (related to the traditionally used contrast parameter y_d) is determined by the slope of the dependence S(D) of the resist solubility rate Son the average exposure dose D.