Plasma technologies for low-k dry etching

A model to predict the process window of SiOCH etching is proposed. The optimum flux condition depends not only on the incident flux from the fluorocarbon plasma but also on the film composition. In etching porous SiOCH, lower film density raises the etch rate, but lower oxygen content reduces the length of the process window. A film with a low H/C ratio easily caused the etch stop.