Simple removal technology using ozone solution for chemically-stable polymer used for MEMS

This paper reports simple removal technology using ozone solution for chemically-stable polymers such as SU-8, BCB, polyimide and carbonized resist. Conventionally, these polymers are difficult to remove completely by O₂ plasma and organic solutions because of their chemical stability and inorganic additives. In this study, these polymers were etched using acetic acid and water solution of ozone. Residue analysis after polymer etching was performed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The analysis demonstrated that the ozone solution could etch and remove these polymers without residue. This strong etching effect might be attributed to strong organic decomposition ability of ozone and rinse effect of inorganic materials in wet process.