Patterning ability of conducting polypyrrole thin films by positive photoresist

Abstract

In this paper, patterning ability of ultra-thin films of conducting polypyrrole deposited on silicon wafer surfaces by in situ chemical polymerization in the presence of different anionic dopants including a-naphthalene sulfonic acid, anthraquinone-2-sulfonic acid sodium salt monohydrate/5-sulfosalicylic acid dehydrate and camphor sulfonic acid has been studied. ''Lift-off process'' combined with photolithography is the used method for largearea and easy fabrication of micro patterns of conducting PPy thin films. In this procedure, a self-assembled mono layer of Py-silane is deposited on a patterned surface of a positive photoresist, followed by immersion of the surface into polymerization solution. After polymerization, positive micro pattern of the conducting PPy thin film appears on the surface by lifting-off the post baked positive photo resist by THF. The results showed deposition and patterning of conducting PPy thin films with nanometer thickness and relatively high range of conductivity with features as small as 3-4.5 lm in lateral dimensions on silicon wafer.