Dialkyl fumarate copolymers: new photoresist materials for deep-ultraviolet and mid-ultraviolet microlithography

摘要

Photopatterning is described using chemically amplified resists formulated from the copolymer of di-t-butyl fumarate and styrene with various acid-photogenerators. Exposure of the materials to deep- and mid-UV light followed by postbaking results in significant changes in solubility and polarity due to carboxylic functions produced on the polymer chain through the action of photogenerated acid catalyst (chemical amplification). As resists, they possess good sensitivity (14-40 mJ/cm$+2$/), contrast ($gamma$GRT@4) and thermostability (up to 300$DGR C). Relief images with good resolution can be readily obtained with either aqueous base (positive-tone) or organic (negative-tone) solvents as developer. Such photoinduced changes of the functional groups in the exposed areas were also used to pattern molecules on the surface at micron-scale, thus generating functional images, as illustrated by the selective binding of fluorescent dyes in either exposed (positive-tone) or unexposed (negative-tone) areas.