Effect of Chelating Agent and Surfactant on TaN CMP in Weakly Alkaline Slurry

Abstract

Co/TaN has been considered as one of the most promising candidates for barrier layers with the feature size of integrated circuit (IC) shrinking to 14 nm and below. The present work investigates the effect of chelating agent and non-ionic surfactant on Co/Cu/TaN CMP in weakly alkaline slurry without any oxidizer. The results show that TaN removal rate increases to the peak value 526 Å/min as the chelator concentration is 1ml/L. That is due to the formation of the water-soluble complex on the surface of TaN. What's more, the TaN removal rate reaches to 501 Å/min and the root mean square roughness (Sq) of TaN is 0.654 nm when non-ionic surfactant concentration is 10 ml/L under the system of 1 ml/L of the chelator. Meanwhile, by the cross-over experiment, it is when slurry is composed of 5 wt% abrasive content, 1 ml/L chelator and 10 ml/L non-ionic surfactant at pH 10 that removal selectivity of Co:Cu and TaN:Cu are comparatively higher and closer (Co:Cu∼2.74:1, TaN:Cu∼2.61:1) along with a good surface quality is obtained.