US Patent 10923393 Contacts and interconnect structures in field-effect transistors

A first conductive feature has a dielectric layer formed thereover. An opening is formed in the dielectric layer to expose a portion of the first conductive feature. A first barrier layer is formed over the first conductive feature and over a top surface of the dielectric layer. A second barrier layer is formed over the first barrier layer and on sidewalls of the opening. The second barrier layer is removed, resulting in at least a portion of the first barrier layer disposed over the first conductive feature. A second conductive feature is formed over the portion of the first barrier layer. Sidewalls of the second conductive feature directly contact the dielectric layer.