Electrochemical characterization of localized corrosion mechanism of ALD Al2O3-coated copper for microelectronic application

Abstract

To achieve performance and reliability in microelectronics devices, copper interconnections must be protected from aggressive environment during the manufacturing process and throughout the life of the devices. Atomic Layer Deposition Al2O3 thin films has been used as a compatible layer with key integration process steps, as well as being corrosion-resistant in neutral media. However, electrochemical tests in aggressive environment have revealed that the alumina prematurely failed to protect copper from localized corrosion. In this study, local and global electrochemical techniques have been employed to evaluate the reactivity of copper at multiple scales and to elucidate the underlying corrosion mechanisms.