Dual damascene etching process

摘要

An etching process yields an optimized formation of via holes through the combination of semiconductor material selection and etchant parameters. Over an interlayer dielectric layer is formed a stop layer having a SiON layer over which is a SiC layer. Selective etching will attack the SiC layer while leaving the SiON layer undisturbed. When etching the via hole, a proportion of about 7:90 O₂:CO was observed to yield a superior etch.