Potassium Permanganate-Based Slurry to Reduce the Galvanic Corrosion of the Cu/Ru/TiN Barrier Liner Stack during CMP in the BEOL Interconnects. (25th February 2016)

• Record Type: Journal Article
• Authors: Sagi, K. V.; Amanapu, H. P.; Alety, S. R.; Babu, S. V.
• Is Part Of: ECS journal of solid state science and technology. Volume 5:Number 5(2016)
• Page Start: P256
• Page End: P263
• Publication Date: 2016-02-25
• Subjects: CMP -- Copper -- galvanic corrosion -- Guanidine carbonate -- KMnO4 -- Ruthenium -- TiN; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0141605jss
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : Chemical mechanical polishing (CMP) behavior of Cu/Ru/TiN barrier liner stack was investigated with a slurry comprising of silica abrasives, potassium permanganate (KMnO4 ), guanidine carbonate (GC) and benzotriazole (BTA) in the alkaline region. The corrosion and polishing behavior of the Cu, Ru and TiN films in the solution consisting of the above additives were characterized by open circuit potential and potentiodynamic measurements, polishing rates, dissolution rates and contact angle measurements. A slurry comprising of 10 mM KMnO4, 1 wt% GC and 5 wt% Silica at pH 10 has shown adequate polish rates as well as low individual film corrosion. However, 1 mM BTA was needed to maintain the ΔECORR of both the Cu/Ru and Ru/TiN couples at <20 mV essential to inhibit any galvanic corrosion while still maintaining low corrosion rates for Cu, Ru and TiN films. The removal rate ratio of Ru:Cu with the optimized slurry was ∼0.8, minimizing the possibility of dishing.