US Patent 9786553 Advanced BEOL interconnect structure containing uniform air gaps

A semiconductor structure including a back-end-of-the-line (BEOL) interconnect structure that contains an air gap located on each side of an interconnect metal or metal alloy structure, is provided wherein each air gap has a uniform (i.e., homogenous) shape. The uniform shape of the air gap can aide in reducing the electrical performance variation which is typically observed with prior art interconnect structures containing air gaps that have a non-uniform shape.