Nano Gas Cluster Dry Cleaning for Damage Free Particle Removal

Abstract

CO2 gas cluster cleaning process for nano particles removal without pattern damage was investigated. Gas cluster cleaning process was performed for generating the nano-sized gas cluster in the vacuum chamber. When pressurized CO2 gas was passed through the convergence-divergence (C-D) nozzle, the high speed and high energy gas clusters were generated. The cleaning force of CO2 gas cluster is related to flow rate of the gas and gap distance between the nozzle and substrate. In our studies, the optimum gas flow rate and gap distance for nano-sized particles removal was found, respectively. Pattern damage tests of the poly-Si and a-Si pattern were also evaluated by SEM images. No pattern damages were observed at these optimum conditions.