Surface-processing-enhanced copper diffusion into fluorosilicate glass

Abstract

This study investigated copper diffusion into processed fluorosilicate glass (FSG). It is observed that the surface process enhances the flatband voltage shift of the Cu/FSG/Si capacitor structure under bias-temperature stress. Secondary-ion mass spectroscopy analysis confirmed that the flatband voltage shift was due to Cu diffusion into the FSG film. Thermal desorption spectrometer analysis indicated that the surface damage layer took up more moisture. A surface-damage-layer-enhanced Cu ionization model was then proposed to explain the observation. The investigation concludes that the diffusion of Cu into FSG is strongly dependent on the surface condition of the FSG film. The proposed model also provides explanation for the inconsistent results reported in previous literature. (C) 2001 The Electrochemical Society.