Influence of Water on Photochemical Reaction of Positive-Type Photoresist

Water content in a positive-type photoresist film has an important role in the photochemical reaction. We have studied how the water content influences the photochemical reaction of a positive-type photoresist. To proceed the reaction, a water supply was required for the positive-type resist film. This phenomenon is remarkably observed in the case of a thick film. The water usually had to be supplied by the moisture in the atmosphere by diffusion on the thin film. Even on a thick resist film, completeness of the reaction was obtained by some treatment of water absorption. By introducing a sufficicient amount of water into a resist film for the reaction while keeping it in air for a long time or soaking it in a water bath, a patterning of the thick resist film was accomplished.