Method for forming a semiconductor interconnect with multiple thickness

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.