The path to better understanding stochastics in EUV photoresist

Abstract

Although in the last year the development of extreme ultraviolet (EUV) lithography has allowed to push the lithographic performance of the EUV photoresists, the high-volume-manufacturing (HVM) requirement to have a cost-effective low exposure dose photoresist (<20 mJ/cm2) remains a big challenge and patterning stochastic defectivity at nano-scale currently still is the major limiting factor of the lithographic process window of EUV resist when looking at tight pitches below 40 nm. To get a better understanding of stochastic patterning failures for such tight pitches it is crucial to quantify them already at the early stage of R&D resist screening phase. In this work we describe a new way of looking at the performance of EUV photoresists. We present the EUV resist nano-failure characterization results when printing dense line-space pattern logic use case on the ASML NXE3300 full field EUV scanner. We analyze through dense pitches three chemically amplified resists with different sensitivity, we quantify the nano-bridges and we discuss potential root causes from photon-shot-noise, imaging and material standpoint.