Plasma-assisted supercritical carbon dioxide removal process for photoresist stripping applications

Because of increasing interest in environmentally benign fabrication process, the use of dry cleaning processes to remove residues of metal, photoresists, organic moieties and particles from surfaces has grown as a research area. In this study, we designed series of systematic approaches to understand the properties of the hard-baked photoresist on glass substrates. We focused on the effects of de-bonding photoresists on the surface by using a plasma-assisted supercritical carbon dioxide removal process with various control parameters. Changes in the surface morphology of plasma de-bonded photoresists were observed and analyzed. A weight-loss method was used to evaluate quantitatively the efficiency of photoresist stripping by SCCO₂. Compared to the blank experiment (SCCO₂ process only), the photoresist residue reduces to 14.7% from 76.3%. This study demonstrates the possibility of incorporating plasma pretreatment into the supercritical carbon dioxide removal process for photoresist stripping applications.