HIGH PURITY TANTALUM TARGETS FOR SPUTTERING

摘要

Improved tantalum-containing barrier layers are obtained by sputter depositing tantalum and/or tantalum nitride from a target having a low contaminant level, i.e., a metallic contaminant content below about 30 ppm by weight; or a niobium contaminant content below about 50 ppm by weight, preferably below 10 ppm, a molybdenum content below about 10 ppm by weight, a gold contaminants below about 15 ppm by weight, and a tungsten content below about 10 ppm by weight. Medium time to failure of copper capacitors including these layers is increased over the use of conventional tantalum targets which have higher amounts of contaminants.