Method of etching a high aspect ratio contact

摘要

Methods and an etch gas composition for etching a contact opening in a dielectric layer are provided. Embodiments of the method use a plasma generated from an etch gas composed of C4F8 and/or C4F6, an oxygen source, and a carrier gas in combination with tetrafluoroethane (C2F4) or a halofluorocarbon analogue of C2F4.