Patent attributes
Methods for resputtering and plasma etching include an operation of generating an ultra-high density plasma using an ultra-high magnetic field. For example, a plasma density of at least about 1013 electrons/cm3 is achieved by confining a plasma using a magnetic field of at least about 1 Tesla. The ultra-high density plasma is used to create a high flux of low energy ions at the wafer surface. The formed high density low energy plasma can be used to sputter etch a diffusion barrier or a seed layer material in the presence of an exposed low-k dielectric layer. For example, a diffusion barrier material can be etched with a high etch rate to deposition rate (E/D) ratio (e.g., with E/D>2) without substantially damaging an exposed dielectric layer. Resputtering and plasma etching can be performed, for example, in iPVD and in plasma pre-clean tools, equipped with magnets configured for confining a plasma.
