Microcontact printing pattern as a mask for chemical etching: A scanning photoelectron microscopy study

Abstract

Synchrotron-based scanning photoelectron spectromicroscopy and microspectroscopy were used to monitor the outcome of the etching process involving the transfer of a lithographic pattern produced by microcontact printing (μCP) of self-assembled monolayers (SAMs) to the underlying metal (gold) substrate. As a test system, octadecanethiolate (ODT) SAMs on gold substrates were chosen. The μCP ODT SAMs were found to protect the underlying gold against the wet-chemical etching, ensuring the effective transfer of the μCP pattern to the substrate. These SAMs exhibited only a slight degradation upon their exposure to the Au-etching solution. In contrast, a significant degradation of the edges of the printed features was observed. This degradation was predominantly related to a lateral diffusion of the active etching agents across these edges, along the SAMs-Au interface. This process can result in a blurring and narrowing of the printing features of a μCP SAM pattern at its transfer to the underlying substrate.