Dual damascene fully-aligned via interconnects with dual etch layers

Abstract

A fully-aligned via interconnect structure is provided in which a first etch stop layer is formed on a first interconnect dielectric material layer containing an electrically conductive line structure to protect the interconnect dielectric material from eroding during metallization used in providing a combined via/line electrically conductive structure in a second interconnect dielectric material layer that is formed above the first interconnect dielectric material layer. The interconnect structure has low resistance due to the maximized contact between the via portion of combined via/line electrically conductive structure and the underlying electrically conductive line structure. Moreover, no bowing or metal fangs are formed, and no metal residue is introduced into the first interconnect dielectric material layer during metallization.