Method for decreasing sheet resistivity variations of an interconnect metal layer

Abstract

According to one exemplary embodiment, a method includes a step of forming a number of trenches in a dielectric layer, where the dielectric layer is situated over a wafer. The method further includes forming a metal layer over the dielectric layer and in the trenches such that the metal layer has a dome-shaped profile over the wafer. The method further includes performing a planarizing process to form a number of interconnect lines, where each of the interconnect lines is situated in one of the trenches. The dome-shaped profile of the metal layer causes the interconnect lines to have a reduced thickness variation across the wafer after performing the planarizing process. The interconnect lines are situated in an interconnect metal layer, where the dome-shaped profile of the metal layer causes the interconnect metal layer to have increased sheet resistivity uniformity across the wafer after performing the planarizing process.