2025/12/29 by Christopher Eom, Kyunghyeon Lee, Gordon S. W. Craig +2 · 1 voice
Engineering · Materials Science · #Block Copolymer Self-Assembly #Nanofabrication and Lithography Techniques #Polymer crystallization and properties
paper · doi:10.1116/6.0005088
openalex created_date 2025/12/29 · openalex publication_date 2025/12/29 · openalex updated_date 2026/06/11
Block copolymers (BCPs) of an A-block-(B-random-C) architecture have been explored as materials for nanolithography because the composition and chemistry of the random block enables modification of thermodynamic and wetting properties to meet manufacturing criteria. Here, A-b-(B-r-C) BCPs created by an amidation reaction of polystyrene-block-poly(pentafluorophenyl methacrylate) (PS-b-PPFMA) with controlled amounts of Si add insight to previous conclusions about the dual contributions of BCP chemistry and reactive ion etch (RIE) gas chemistry on etch properties. We focus on two RIE etch characteristics: organosilicon etch resistance in H2/N2 plasma etching and enhanced removal of non-styrenic structures in an Ar/O2 etch. Consistent with previous studies, higher amounts of Si result in greater etch resistance under H2/N2 RIE, where at least ∼10 wt. % Si is necessary to exhibit sufficient etch resistance. By contrast, Ar/O2 etching resulted in etch rates independent of Si content. We observe previously unreported surface roughening aligned with morphological domains during the H2/N2 etch of modified PS-b-PPFMA BCPs. Limited in the amount of allowable Si to attain equal surface energy between blocks, these BCPs are further disqualified in forming a Si-containing mask. However, in an Ar/O2 etch, the same BCPs exhibit suitable etch contrast and smooth domain structures, forming a uniform PS mask. Ultimately, this study uses the chemical flexibility of these materials to demonstrate the mechanisms of interactions between BCP and etch chemistry that must be considered to design effective materials for pattern transfer applications.