Trench structure for high performance interconnection lines of different resistivity and method of making same

Abstract

An integrated circuit includes a substrate with an interlevel dielectric layer positioned above the substrate. First trenches having a first depth are formed in the interlevel dielectric layer and a metal material fills the first trenches to form first interconnection lines. Second trenches having a second depth are also formed in the interlevel dielectric layer and filled with a metal material to form second interconnection lines. The first and second interconnection lines have a substantially equal pitch, which in a preferred implementation is a sub-lithographic pitch, and different resistivities due to the difference in trench depth. The first and second trenches are formed with an etching process through a hard mask having corresponding first and second openings of different depths. A sidewall image transfer process is used to define sub-lithographic structures for forming the first and second openings in the hard mask.