Characterization of the SilSpin etch-back (breakthrough) process for nanolithography with CHF₃ and O₂ gas chemistry

This study characterizes 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 Standard Reactive Ion Etch (RIE) platform which etches the polymers at a slower rate than a high density plasma reactor. The goal of the study was to determine the significant process parameters in the SilSpin Etch-Back process using a magnetically enhanced reactive etching (MERIE) reactor with CHF₃ and O₂ gas chemistry. The experimental approach taken uses a 2 factorial design to characterize the relationships between the process factors and etch responses. The factors in the design are: reactor pressure, RF power, gas ratio, and magnetic flux. The significant factors and their interaction levels to uniformly etch the SilSpin in the MERIE were determined along with the best set of operating parameters. This information applied through the response surface methodology enabled the development of empirical etch behavior models. Subsequently, the contour plots illustrated a desirable operational region for each factor.