US Patent 7135396 Method of making a semiconductor structure

Methods of making a semiconductor structure are disclosed. A refractory metal layer containing W, TiW, Ta, or TaN and semiconductor layer are formed on a substrate that contains copper in, for example, a via therein. A portion of the refractory metal layer and semiconductor layer is removed by etching using a fluorine-containing compound. By using W, TiW, Ta, or TaN as the refractory metal layer material and employing fluorine-based etching, the copper portion in the substrate is not substantially etched, thus preventing corrosion of the copper portion.