A Selective Etching Solution for Use with Patterned Self-Assembled Monolayers of Alkanethiolates on Gold

Abstract

Nl icrocontact pr int ing t r rCPtr is a technique that generates patterned self-assembled monolayers lSAtr{s t2 of' alkanethiolates t typically, hexadecanethiolate ) on the surfaces of goid,1 silver,l l and copper,l and of alkylsiloxanes on hydroxyl-terminated surf'aces.r' Patterned SAI{s of alkanethiolates serve as nanomc.ter-thick resists in certain etching solutions: the one we i.rave. used most extensively when gold is the underiving substrate has been aqueous KCN so lu t ion (p l l ' . 1 t . ICN ] . . ,0 .1 M) saturated with 0z.6 Llsing this etchant. t l-re patterns in the SAMs can be transf'erred faithfuih' into the thin fi lms of gold; the resulting patterns of gold can be used subsequently as secondarv masks for the etching (isotropic or anisotropic ) of' underlving la.vers of sil icon dioxide and si l icon; ' or i ls funct ional e lements ( for example, for microerlectrodese and diffraction gratingsi0). Microcontact printing is renrarkablv convenient fbr the fabrication of structures rvith feature sizes of 1 zrm and larger: it can be r-rsed. rvith more diff iculty and less reliabil itv. to fabricate f 'eatures with sizes down to 100