Corrosion Inhibition by Thiol-Derived SAMs for Enhanced Wire Bonding on Cu Surfaces

Formation and stability of thiol-derived self-assembled monolayers (SAMs) on Cu surfaces have been investigated using a multitechnique characterization approach, including contact angle measurements, X-ray photoelectron spectroscopy, ellipsometry, and electrochemistry. High-quality SAMs were formed on Cu surfaces under various conditions of substrate preparation, thiol molecular structure, adsorption from the gas and liquid phases, concentration, solvent effects, and self-assembly time. Stability studies exploring SAM resistance to aging, processing chemicals, temperature, and electrochemically induced oxidation-reduction reactions demonstrate promising corrosion inhibition properties. The feasibility of exploiting SAMs in microelectronics applications was demonstrated by the enhancement of Cu wire bonding onto thiol-passivated Cu bond pads. © 2004 The Electrochemical Society. All rights reserved.