Fabrication Process of Multi-step Grating by Chemical Method

ZrO² gel film was prepared from zirconium tetra-n-butoxide chemically modified with benzoylacetone by the sol-gel method. The obtained gel film shows an absorption band, characteristic of the π-π^* transition of chelate ring, at around 336 nm. The absorption band associated with the chelate ring gradually decreases in intensity with UV-irradiation using a high pressure mercury lamp. It indicates that the chelate ring is dissociated by the UV-irradiation and that the gel film exhibits photosensitivity. Utilizing the photosensitivity, patterns (about 210 μm) with complex micro-structure could be fabricated by UV-irradiation through masks and leaching.