US Patent 11244897 Back end of line metallization

Interconnect structures and methods for forming the interconnect structures generally include a subtractive etching process to form a fully aligned top via and metal line interconnect structure. The interconnect structure includes a top via and a metal line formed of an alternative metal other than copper or tungsten. A conductive etch stop layer is intermediate the top via and the metal line. The top via is fully aligned to the metal line.