Polymeric Self-Assembled Monolayers. 3. Pattern Transfer by Use of Photolithography, Electrochemical Methods, and an Ultrathin, Self-Assembled Diacetylenic Resist

Abstract

We report herein that a substrate can be patterned using a diacetylenic, self-assembled monolayer (SAM) resist and photolithographic and electrochemical methods. Our proof-of-concept experiments result in micron-scale pattern transfer onto Au substrates, but extension to other materials, including Si, Al, and GaAs, and nanometer-scale patterning will be straightforward. It is demonstrated that a SAM composed of diacetylenic organomercaptans can be used as a negative photolithographic resist. The importance of this method results from the fact that the resist is highly organized, thin, and largely defect free. These factors ensure high-resolution patterning and control over the surface energy and reactivity of the resist itself, which permits an added dimension of control over surface processing. In addition, resist stripping involves only gentle and easily controlled electrochemical methods. Moreover, we have previously shown that organized multilayers of polydiacetylenic SAMs can be easily formed, so resist thickness can be controlled over a broad range. Finally, unique electronic and photonic properties of the polymeric SAMs might themselves be integrated into Si-based devices using this lithographic approach in the future. 34 refs., 2 figs.