Abstract: A conductive line varies in thickness to assist in overcoming RC delays and noise coupling. By varying line thickness, variation in conductor width is avoided if necessary to maintain a specified minimum pitch between conductors while maintaining predetermined desired RC parameters and noise characteristics of the conductive line. Conductor depth variation is achieved by etching a dielectric layer to different thicknesses. A subsequent conductive fill over the dielectric layer and in the differing thicknesses results in a conductive line that varies in thickness. Different conductive line thicknesses available at a particular metal level can additionally be used for semiconductor structures other than a signal or a power supply conductive line, such as a contact, a via or an electrode of a device. The thickness analysis required to determine how interconnect thickness is varied in order to meet a desired design criteria may be automated and provided as a CAD tool.

Abstract: A hardmask layer (34) is formed over insulating layers (26, 24, 22 and 20), and an antireflective layer (36) is formed overlying the hardmask layer (34). A resist layer (38) is formed overlying the antireflective layer (36), and an opening is formed in the resist layer to expose a surface portion of the antireflective layer (36). The exposed surface portion of the antireflective layer (36) and portions of the hardmask layer (34) are etched to expose a surface portion of the insulating layers (26, 24, 22 and 20), and a feature opening (61) is formed in the insulating layers (26, 24, 22 and 20). A conductive material (74) is deposited to fill the feature opening (61), and portions of the conductive material (74) lying outside the opening are removed.