Semiconductor devices and methods of manufacture thereof

Abstract

Semiconductor devices and methods of manufacture thereof are disclosed. In some embodiments, a semiconductor device includes conductive features disposed over a workpiece, each conductive feature including a conductive line portion and a via portion. A barrier layer is disposed on sidewalls of each conductive feature and on a bottom surface of the via portion of each conductive feature. The barrier layer includes a dielectric layer. A first insulating material layer is disposed beneath a portion of the conductive line portion of each conductive feature. A second insulating material layer is disposed between the conductive features. A third insulating material layer is disposed beneath the first insulating material layer and the second insulating material layer. A lower portion of the via portion of each of the conductive features is formed within the third insulating material layer. The second insulating material layer has a lower dielectric constant than a dielectric constant of the first insulating material layer and a dielectric constant of the third insulating material layer.