Factors affecting photosensitivity enhancement of chemically amplified photoresists by an acid amplifier

The acid proliferation reaction of tert-butyl 2-methyl-2-(tosyloxymethyl)ac etoacetate to liberate the corresponding sulfonic acid by the action of a t iny amount of photogenerated acid was investigated in positive- and negativ e-working chemically amplified photoresists. The addition of the acetoaceta te as an acid amplifier to the photoresists resulted in a marked improvemen t in contrast, while the level of photosensitivity enhancement was relative ly small for both types of photoresists, showing that the inconspicuous enh ancement of photosensitivity is due to the suppression of the diffusion of acidic species in polymer films. The marked improvement of photosensitivity was achieved by the fabrication of novel double-layered photoresists doped with the acid amplifier.