SINGLE-LAYER CHEMICALLY AMPLIFIED PHOTORESISTS FOR 193-NM LITHOGRAPHY

Recent advances in ArF excimer laser exposure tools have led to a sear ch for new resist materials for use at 193 nm. To date much of this ef fort has been directed toward surface imaged or bilayer resist schemes and only recently have there been reports of single layer systems wit h sufficient transparency for use at this short wavelength. We will de scribe our approach to a 193 nm single layer resist system based on me thacrylate terpolymers. A terpolymer system based on tert-butylmethacr ylate, methyl methacrylate and methacrylic acid developed for laser di rect imaging applications has been adapted for high resolution imaging by modifying the terpolymer composition and by optimizing the photoac id generator loading. This resist is useful for the characterization o f new exposure systems and we will describe imaging results on a proto type 0.50-NA step and scan system. We will also describe the effect ph otoacid structure has on the imaging properties of the resist and comp are the efficiency of deprotection chemistry at 193 and 248 nm. In add ition, we will discuss modifications of the aliphatic polymer describe d above by replacement of the ''inert'' methyl methacrylate monomer by monomers containing alicyclic substituents to improve the resistance to reactive ion etching.