Dual Damascene Reactive Ion Etch Polymer Characterization through X-Ray Photoelectron Spectroscopy for 65 nm and 45nm Technology Nodes

At 65nm and beyond technology nodes, copper interconnect formation in dual damascene integration is continually challenged from a polymer management perspective. Highly polymeric plasma chemistry is required to reduce line edge roughness, shape physical profile, and control critical dimension across a 300mm wafer. But too much fluorocarbon deposition on a wafer results in poor defects yield. In this paper, X-ray photoelectron spectroscopy (XPS) characterization technique is used to quantify and to optimize a metal line reactive ion etch process to increase electrical opens yield. A reduction of 2 at.% in carbon mass results in a Do (defects/cm2) improvement from > 2.0 to less than 1.0. This result is realized without a shift to the trench physical profile which is important for reliability performance. Moreover, with a shorter turnaround time of XPS characterization compared to electrical hardware splits, quicker yield learning cycle is realized for both RIE process and module integration.