Synthesis of polysulfides containing the triazeno group and their application as photoresists in excimer laser polymer ablation

Two bifunctional unsaturated monomers containing the photosensitive triazene group were synthesized and reacted with dithiols. A radical polyaddition afforded polysulfides which carry the photosensitive chromophores in their backbone. The molar masses reach up to 10 400 g/mol and the glass transitions range between -2 and 39 degrees C. With respect to their application as dry photoresists for excimer laser ablation, thermo- and photolytical decomposition of monomers and polymers were investigated. TGA measurements revealed that the polymers were stable up to 255 degrees C, slightly below those of the monomers (270 degrees C). For photolysis in solution observed by UV/vis spectroscopy, the triazene absorption vanished on a time scale of seconds. Pulsed laser patterning was performed at 193 nm and with PMMA as a reference system. The sensitivity of the resists to irradiation was higher for PMMA and also the structural precision seemed to be slightly better for the standard, both probably owing to the applied wavelength. In contrast, the amount of redeposited material and the roughness of the polymer surface could be improved by using the triazene-containing resists.