Advanced Technology and Manufacturing Institute (ATAMI)

Hafnium Oxide thin films has had growing attention due hafnium oxide being used as a gate dielectric for MOSFET transistors and a potential next generation photoresist for sub 20 nm patterns. Extreme Ultra-Violet (EUV) lithography has been identified as the primary candidate technology for generation of sub-20 nm patterns. Current polymer based resists exhibit significant limitations at these resolutions due to high edge roughness, low etch resistance and high aspect ratio. Inorganic resists have gained much attention recently due to the high achievable resolution, high etch resistance and low edge roughness but generally suffer from low sensitivity to EUV photons. The low intensity of current EUV sources necessitates significantly higher sensitivity than what has been demonstrated for purely inorganic high resolution resists. A hybrid organic inorganic approach shows significant promise for potential next generation resists by binding photo sensitive organic ligands onto a metal oxide to produce a negative tone photoresist. In this study we sought to characterize the sol-gel deposition of HfO₂ thin films and the interactions of molecular and atomic species from carboxyl functionalized HfO₂ thin film to gain insight into the thermal and radiation induced desorption characteristics that ultimately enable sensitivity improvement of inorganic films. Two different carboxylic acid ligands (Methacrylic Acid and Benzoic Acid were used in this surface characterization study. The Hafnium Oxide films with a self-assembled monolayer of carboxylic acids were characterized via ATR FT-IR, water droplet contact angle, X-ray photoelectron spectroscopy (XPS), Temperature Programed Desorption (TPD) and Electron Stimulated Desorption(ESD).