Organotin bearing polymeric resists for electron beam lithography

In recent time, inorganic and organic-inorganic hybrid resists are gaining considerable attention of resist community as the presence of inorganic component helps in improving many properties. The present work reports the development of an organotin bearing functional polymeric positive tone resist (FPPTR-1) comprised of rationally chosen four monomeric units viz. triphenylsulfonium salt 4-(methacryloxy) 2,3,5,6-tetrafluorobenzenesulfonate (F4-MBS-TPS), tertiary butyl acrylate (TBAC), γ-butyrolactone methacrylate (GBLMA) and acetoxydibutyltin methacrylate (ADBTMA). The resulting polymer was characterized using Nuclear Magnetic Resonance (NMR) spectroscopy, gel permeation chromatography (GPC), Fourier Transform Infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) techniques. The polymer has good thermal stability (~195 °C), and weight average molecular weight (Mw) was found to be ~9480. AFM studies revealed that the present functional polymer can form smooth film with low roughness. It showed good sensitivity to electron beam exposure (83 μC/cm2). It was established through electron beam lithography (EBL) studies that FPPTR-1 can be used as thermally stable positive tone e-beam resist with good contrast (~9.87) and sensitivity for nanopatterning of both thin (~30 nm) and relatively thick (~100 nm) film applications. We successfully patterned dense, isolated and complex nanofeatures using EBL.