Modeling and verification of next-gen EUV mask absorbers

Rajiv Sejpal; William Maguire; Bruce W. Smith

doi:10.1117/12.2660823

28 April 2023 Modeling and verification of next-gen EUV mask absorbers

Rajiv Sejpal, William Maguire, Bruce W. Smith

Proceedings Volume 12494, Optical and EUV Nanolithography XXXVI; 124940H (2023) https://doi.org/10.1117/12.2660823
Event: SPIE Advanced Lithography + Patterning, 2023, San Jose, California, United States

Abstract

Layout designs are reaching the resolution limit for 0.33NA extreme ultraviolet lithography (EUVL) systems, with 0.55NA high-NA on the horizon. Alternative mask designs at reduced absorber thickness for higher image contrast have become necessary. Novel absorber candidates are classified as attenuated phase shifting mask (attPSM) absorbers, high-k mask absorbers and index matched absorbers (n ≈ 1) based on the complex refractive index (n – ik). We identify absorber candidates through effective media approximation (EMA) model and discuss design considerations for attPSM absorbers. Optimum phase shift for EUV attPSM is higher than π and it is influenced by the absorber material, diffraction angle at the mask, mask pattern, NA and absorber reflectivity. Index matched mask absorber designs with higher extinction coefficient are also proposed as promising candidates.

Conference Presentation

Citation Download Citation

Rajiv Sejpal, William Maguire, and Bruce W. Smith "Modeling and verification of next-gen EUV mask absorbers", Proc. SPIE 12494, Optical and EUV Nanolithography XXXVI, 124940H (28 April 2023); https://doi.org/10.1117/12.2660823

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