Characterisation of the SilSpin etch-back process for nanolithography with CHF₃ and O₂ gas chemistry

This study characterises the SilSpin™ etch-back process within the reverse tone Step and Flash Imprint Lithography (SFIL/R). Currently, the S-FIL/R operational specifications to etch the SilSpin material require a reactive ion etching platform which etches the polymers at a slower rate than a high density plasma reactor. The goal was to develop empirical etch models and determine the process parameters in the etching process using a magnetically enhanced reactive ion etching reactor with CHF₃ and O₂ gas chemistry. The experimental approach taken uses a 2⁴ factorial design to characterise the relationships between the process factors and etch responses. The factors in the design are: reactor pressure, power, gas flow and magnetic flux. The factors and their interaction levels to uniformly etch the SilSpin were determined along with the best set of operating parameters. Using these results in conjunction with response surface methodology enabled the development of empirical etch behaviour models.