Abstract: Awater-based chemical amplified photoresist, which is composed of Novolak resin, hexamethoxylmethyl melamine(HMMM), diphenyliodonium salt and photosensitizer was investigated. It was found that the diphenyliodonium salt can act not only as the photosensitive acid generator, but also as the dissolution inhibitor. As a photosensitive acid generator, the diphenyliodonium salt can generate acid after exposure, which catalyzes the condensation of Novolac-HMMMsystem in post-exposure bake step. Using the alkali-ethanol aqueous solution as the developer the photoresist can be of negative tone. As a dissolution inhibitor, the diphenyliodonium salt can prevent the unexposure film from being dissolved in the developer. Therefore, using the dilute alkali aqueous solution as developer this photoresist can be of positive tone. Image reversal can be achieved by selecting different developer and different photographic process. The negative tone image and the positive tone image were obtained by the optimized photolithographic parameters.

Key words: Chemical amplified, Photosensitive acid generator, Dissolution inhibitor, Negative photoresist, Positive photoresist