Etching technology using ozone for chemically stable polymer in MEMS

We have developed the etching technology using an ozone solution for chemically stable polymers such as polyimide, SU-8 and BCB, which are often used for MEMS, and a carbonized resist. Conventionally, these polymers are difficult to remove by O₂ plasma and organic solutions. In this study, the etching experiments of these chemically stable polymers were carried out using an acetic solution of ozone. The residues after the etching of the polymers were evaluated with surface profiler, scanning electron microscope and X-ray photoelectron spectroscopy. It was demonstrated that the acetic solution of ozone can etch and remove these polymers without residue. The developed method can remove not only organic polymers but also polymers containing inorganic materials, and is safe and easy.