Selective surface modification and patterning by a micro-plasma discharge

We demonstrate a selective surface patterning method by a micro-plasma discharge. In this method, argon plasma is ignited through a hole of copper clad polyimide microstructure electrodes. We described here experiments in which an octadecanethiol [CH3(CH2)(17)SH] self-assembled monolayer (SAM) on a gold film is exposed to a microdischarge, followed by immersion of the sample in 16-mercaptohexadecanoic acid solution. The octadecanethiol SAM is desorbed upon Ar plasma exposure, allowing the formation of a second SAM on the damaged region. The spatial resolution in the present experiments is limited by the dimension of microstructure electrodes. The patterned samples are viewed by using optical microscope and scanning electron microscopy. The advantage of this approach is that it is noncontact and eliminates the need of photolithography. (C) 2005 American Institute of Physics.