{'fraction_non_alphanumeric': 0.020452885317750184, 'fraction_numerical': 0.0007304601899196494, 'mean_word_length': 5.313364055299539, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Metrics for stochastic scaling in EUV lithography

Background: The stochastic nature of extreme ultraviolet (EUV) lithography produces many undesirable effects such as line-edge roughness and local critical dimension variations. These stochastic problems are worse when trying to manufacture at high throughput and high resolution. Aim: There is a need for greater understanding of the sources of stochastic variability in EUV lithography, and whether photon shot noise or photoresist variabilities dominate. Approach: From first-principle arguments, the basic scaling relationships of roughness versus dose, image quality, and resist properties can be derived that account for most of the important affects that control stochastic outcomes. Results: From these derivations, it is shown that acid yield controls the relative importance of resist versus photon shot noise, with acid yield equal to 1 producing equal contributions of acid shot noise and photon shot noise. Quencher adds uncertainty to the amount of acid generated, but the increase in final latent image gradient can make up for this increase in noise with less loss in signal. Conclusions: Although a full model of line-edge roughness is not complete (with much more work yet to be done), the results to date provide a roadmap for resist design, though without a silver bullet for roughness improvement.