Photosensitive UV resist of poly(methyl methacrylate) containing a bisazide compound

Abstract

Poly(methyl methacrylate) (PMMA) doped with a photosensitive aromatic bisazide compound, 2,6-bis(4-azidylbenzylidene)-4- methyl cyclohexanone, was prepared and evaluated as a negative UV resist. Poly(methyl methacrylate) does not have mid-UV sensitivity because it does not absorb UV-light above 250 nm. However, when PMMA is doped with the above bisazide compound, it exhibits mid-UV sensitivity in an exposure range of 15 to 25 mJ/cm 2 (50 times more sensitivity than normally used positive tone PMMA) to give 50% film thickness remaining on the substrate after development. The doping of bisazide had the effect of reversing PMMA from positive tone to negative tone. The resist was successfully applied to contact printings followed by wet development processing using a one-to-one ratio of toluene and xylene as developer. The sensitivity of this PMMA-bisazide resist depends on the bisazide concentration in PMMA solution, and the spatial resolution was determined to be better than 1 μm.