Patent ID: 7960838

Claim:
An interconnect structure, disposed on a substrate with a conductive part thereon and comprising: a dielectric layer on the substrate, covering the conductive part; a composite contact plug or via plug in the dielectric layer comprising: a first contact plug or via plug extending vertically; and a second contact plug or via plug, extending vertically, directly on the first contact plug or via plug, wherein a top portion of the first contact plug or via plug and a bottom portion of the second contact plug or via plug are different in critical dimension, the first contact plug or via plug is disposed just above the conductive part and a bottom surface of the first contact plug or via plug electrically connects with the conductive part; a first barrier layer disposed between the first contact plug or via plug and the second first contact plug or via plug; and a conductive line on the dielectric layer, electrically connecting with the composite contact plug or via plug.