Investigation of Resist Characteristics of Fluoropolymer for 157nm Lithography.

Recently, fluoropolymers have become promising base resins for single-layer resist uses in 157nm lithography. The 157nm positive-tone resists we studied displayed good optical transparency at 157nm (absorption coefficient of 1.9 to 2.7μm-1). In addition, these polymers showed good exposure sensitivities ranging from 3.5 to 5mJ/cm2, and high contrast for their dissolution rate curves using an improved dissolution rate monitor for thin film thickness. One of the modified 150nm film thickness resists has achieved 100nm lines and space pattern resolution on SiON substrate using a 157nm stepper (NA 0.60, σ 0.3) with a phase shift mask.