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 T g 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.