An Optimized Method for Cu CMP Dishing Improvement

With the development of advanced semiconductor device features shrinking, chemical mechanical polishing (CMP) is becoming an enabling technology to meet the precise machining in various applications. At the same time, the topography of wafer surface shows more and more serious challenges in advanced technology and beyond technology node. Tighten post CMP dishing, pattern loading and uniformity performance control has been evaluated during Cu CMP process. However, it is difficult to improve the Cu dishing and oxide dishing of the interconnect metals for copper CMP process at the same time, because of the selectivity of CMP slurry is fixed. This paper will present how to improve both Cu dishing and oxide dishing control with optimized NDC polish methodology. Experiment results shown that with the NDC CMP process, both Cu and oxide area show better dishing performance.