Fundamentals of resist stochastics effect for single-expose EUV patterning

Abstract

As the industry looks to extend single-expose extreme ultraviolet (EUV) lithography, stochastic effects become a significant concern to enable yield, for both trench and via levels. Multiple previously-published reports have shown a strong tradeoff between resist sensitivity and observed stochastic defectivity. However, the limits of this trade-off between improving stochastics-related defects with a higher dose resist remains to be understood. How strongly does the resist formulation itself contribute to stochastics, or is it a purely dosedriven effect? In this paper, we perform a systematic evaluations of resist component variants to determine the relative effects of photon shot noise induced stochastics vs material stochastics. Material contributions are probed through formulation component and reaction kinetics changes. The defectivity at post-exposure and post-etch are correlated to electrical yield to validate the evaluation. The effect of material and dose contribution to defectivity process window enables to highlight the significant and challenging task of addressing material stochastics that can be convoluted with photon shot noise.