Impact of increasing EUV absorption of CAR polymers on lithographic performance

Abstract

Chemically amplified resists (CAR) enable the transition of extreme ultraviolet (EUV) lithography to high-volume manufacture (HVM). Novel photoresists continue to be designed to meet the simultaneous improvement of resolution, line width roughness, and sensitivity (RLS) trade-off. The absorption of EUV photons in the photoresist film leads to emission of primary electrons to form secondary electrons by inelastic scattering events which in turn leads to the activation of the photoacid generator compound. A unique challenge for the use of CAR in EUV lithography is their poor absorption at 13.5nm wavelength. Understanding the photoresist EUV absorption impact on lithographic performance parameters is critical for photoresist design. In this study, we designed photoresist polymers with tuned EUV absorption coefficients by incorporating EUV absorption group(s) onto different CAR polymers. The effect of the EUV absorption increase on polymer properties as well as on resist lithographic performance will be presented.