A dual damascene process for low-k or ultra low-k dielectric such as organo-silicate glass (OSG). After the via (112) etch, a trench (121) is etched in the OSG layer (108) using a less-polymerizing fluorocarbon added to an etch chemistry comprising a fluorocarbon and low N2/Ar ratio. The low N2/Ar ratio...http://www.google.com.au/patents/US6455411?utm_source=gb-gplus-sharePatent US6455411 - Defect and etch rate control in trench etch for dual damascene patterning of low-k dielectrics
