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When the technology node goes down to 7nm and below, cobalt (Co) has been identified as the promising candidate for the inter-connect/contact material. In this paper, we investigated the effect of amine based chelating agent and H2O2 on cobalt contact chemical mechanical polishing (CMP) in colloidal silica based slurry at pH 8. It revealed that the combination of H2O2 and FA/O II can significantly improve the cobalt removal rate (RR) by an order of magnitude. The electrochemical measurements, X-ray photoelectron spectroscopy (XPS), UV-visible (UV-vis) spectroscopy experiments were applied to explore the removal machanism of Co film. The high removal rate of Co may be due to the formation of the water-soluble Co(III)-FA/O II complex. And relatively low dissolution ([?]1 nm/min) and good surface quality was achieved by adding a novel corrosion inhibitor.

Cobalt (Co) has been identified as the promising candidate material due to the technology node goes down to 7nm and below. In this paper, the effect of diethylenetriamine pentaacetate pentapotassium (DTPA) on chemical mechanical polishing (CMP) of cobalt (Co) in H2O2based slurry at pH 9 was studied. The roles of DTPA on the Co material removal process are discussed and a removal mechanism is proposed. The studied result shown that the removal rate (RR) was significantly improved by added DTPA, due to the Co and DTPA reaction Co-DTPA complex. The test results of electrochemical, UV-Vis and XPS also shows the DTPA has obvious chelation for Co.