US Patent 10453700 Low damage low-k dielectric etch

A method of forming an interconnect structure for an integrated circuit. A dielectric stack is formed on the substrate including an etch-stop layer, a low-k or ULK dielectric layer, and a hard mask layer. The low-k or ULK dielectric is etched using at least two etching processes wherein each etching process is followed by an etch repair process where the etch repair process includes flowing at least one hydrocarbon into the reactor and generating a plasma. The photoresist may be removed using at least two ashing processes wherein each ashing process is followed by an ash repair process where the etch repair process includes flowing at least one hydrocarbon into the reactor and generating a plasma.