Photochemical crosslinking and enzymatic degradation of poly(3-hydroxyalkanoate)s for micropatterning in photolithography

Biodegradable poly(3-hydroxyundecenoate) (PHU) films on silicon wafers were crosslinked with UV light under patterned masks. The films were eked most efficiently whets irradiated in the presence of diphenyl(2,4,6-trimethylben zoylphosphane oxide)as the initiator. Crosslinked patterns were developed, with. depolymerase solution because crosslinked teas degraded much more slo wly than natural PHU. Patterned images with thicknesses of as low as 2.5 mu m were obtained showing the potential application of PHU in microlithograph y as a photosensitive material, which is friendly to the environment.