The Impact of Fluoropolymers on Line Edge Roughness in 193nm Imaging

We report here a family of tetrafluoroethylene (TFE) based photoresist polymers that image at 193 nm with low line edge roughness relative to other candidate polymers, while also demonstrating good resolution, high contrast, high transparency at the imaging wavelength and widely tuneable dissolution rates. These polymers are typically composed of (TFE), cyclo-olefins such as norbornene with one or two pendant hexafluorisopropanol groups per monomer and various acrylates. A solubility switch is incorporated into either the cyclo-olefin or the acrylate monomers. These polymers have the flexibility to easily incorporate a wide range of monomers to enhance properties such as solubility and adhesion. Imaging using Lucent's 0.6 NA SVGL stepper with an altPSM is shown. Contrast, optical absorption and dissolution data are also discussed. We have demonstrated a process for manufacture of these polymers that is scaleable to commercial volumes and which results in exceptional compositional uniformity and acceptably low levels of impurities.