Fabricating metal structures with taper angles and smooth sidewalls

Metal structures with taper angles and smooth sidewalls are very useful in theoretical analyses. In this study, an approach for implementing this kind of metal structure is developed, and an analytical model is discussed in detail. Using this method, an experimental investigation on plasma etching of Mo is conducted. By optimizing the process parameters, Mo lines with taper angles that can be adjusted from 15 degrees-90 degrees are achieved, and the minimum sidewall roughness is 0.8 nm.