Preparation of new photosensitive ZrO2 gel films using hydroxyl-substituted aromatic ketones as chemical modification reagents and their patterning

ZrO2 gel films were prepared from zirconium tetra-n-butoxide chemically modified with one of hydroxyl-substituted aromatic ketones and 1'-hydroxy-2'-acetonaphthone, by the sol-gel method. The obtained gel film showed an absorption band, characteristic of the pi-pi* transition of chelate ring, at around 410 nm. The band was shifted to longer wavelength region than those for the gel films using beta-diketones. The reason is thought that the hydroxyl-substituted aromatic ketone has pi-electron system to form the condensed chelate ring. The absorption band associated with the chelate ring gradually decreased in intensity with UV-irradiation using a high pressure mercury lamp. This indicates that the chelate ring dissociates by the UV-irradiation and that the gel film exhibits photosensitivity. Utilizing the photosensitivity, fine patterns ( about 1 mum) could be fabricated by UV-irradiation through a mask and leaching.