157-nm single-layer resists based on advanced fluorinated polymers

Various polymer structures for 157-nm lithography have been vigorously developed for post 193-nm lithography. Polymers with a fluorinated main chain can improve high transparency at the 157-nm wavelength; conversely, norbornene copolymers with fluoride pendant groups do not achieve so high transparency at the 157-nm wavelength. We have developed a novel 157-nm chemically amplified resist. It is composed of a fluorinated monocyclic main-chain polymer, which shows high transparency and can be used for single layer resists. This new resist is referred to as a Small Absorbance Fluorine contAining ResIst (SAFARI). The SAFARI resist exhibited high-resolution patterns of 65-nm line and space patterns using a 0.85 NA microstepper, good sensitivity of 4 mJ/cm², and high transparency when applied to 250-nm film thickness.