Deep UV Ablation of PMMA Resists

Abstract
Deep UV exposure of Polymethyl methacrylate resist systems has been investigated in the spectral region 220–250 nm using a special deep UV light source. The ablation of PMMA resist follows a quantitative exponential relation and is independent of molecular weight and substrates. The erosion rates at higher temperatures show a dependence on the Tg of the PMMA. The ablation suggests depolymerization reactions in PMMA concurrent to chain scission. Reaction pathways in deep UV degradation are different from electron beam and ion beam degradations of PMMA.