Improvement of EUV contact hole pattern rectification using novel directed self-assembly materials

Single exposure extreme ultraviolet (EUV) lithography advances further device feature scaling that replaces multi-patterning techniques with ArF immersion lithography. As the patterning requirements have been tightened by reduction of circuit dimensions, inhomogeneity inside conventional EUV photoresists such as chemically amplified resists (CAR) present a technical challenges like dimensional non-uniformity and associated defects in EUV patterns, because EUV photons having a wavelength of 13.5 nm lead photon shot noise in EUV patterns. Directed self-assembly (DSA) is a well-known technology for rectifying the resist pattern quality printed by photolithography. Many studies have shown that EUV lithography combined with DSA using block copolymers (BCP) can significantly mitigate the variability of stochastics from EUV lithography. In this study, we investigate the DSA rectification process for contact hole (C/H) patterns by developing and testing a newly designed high-chi (HChi) BCP to achieve better rectification performance such as local critical dimension uniformity (LCDU) and pattern placement error (PPE) as compared to polystyrene-block-polymethylmethacrylate (PS-b-PMMA) which was used as a reference. We also examined the effect of process and material parameters for performance improvement.