Simple Removal Technology of Chemically Stable Polymer in MEMS Using Ozone Solution

This paper reports simple removal technology for chemically stable polymers, such as SU-8, benzocyclobutene, polyimide, and carbonized resist, using ozone solution. Conventionally, these polymers are difficult to completely remove by O₂ plasma and organic solutions because of inorganic additives and chemical stabilities. In this paper, the removability of ozone solution to these polymers was investigated. Etching experiments using aqueous and acetic acid solutions of ozone were performed, and the surfaces of etched samples were analyzed by scanning electron microscopy and X-ray photoelectron spectroscopy. It was demonstrated that the polymers could be etched and completely removed using the acetic acid and/or aqueous solutions of ozone. This strong polymer removability of the ozone solutions is attributed to the strong organic decomposition ability of ozone and the rinse effect to inorganic materials in wet process.