The Leakage Current Conduction Mechanisms of Cu/Porous Silica Damascene Schemes with Nano-cluster TaSi x Barrier

• Published in: Japanese Journal of Applied Physics 2005-01, Vol.44 (1R), p.102
• Main Authors: Chen, Chung-Hsien, Chang, Chin-Piao, Huang, Fon-Shan
• Format: Article
• Language: English
• ISSN: 0021-4922; 1347-4065
• DOI: 10.1143/JJAP.44.102

Leakage current conduction mechanisms of Cu/porous silica damascene structures with TaSi x (20 nm) barrier were investigated. Polycrystalline TaSi 0.54 and nano-cluster TaSi 0.42 barriers were prepared by dc sputtering with various power and pressure. The newly developed silica based slurry was employed for the metal-CMP of TaSi x films. The incorporation of traditional NH 4 OH solution and megasonic were applied to perform post-CMP cleaning. Auger mapping revealed clearly straight Cu and Ta lines in these TaSi x samples. The line-to-line leakage current density ( J L ) was plotted versus the electric field ( E ) at various temperatures. The Ln( J L )–( E ) 1/2 plots showed that Ln( J L ) is linearly dependent on ( E ) 1/2 , corresponding to Schottky emission mechanism. The slope of straight lines were determined from the data points of the Ln( J L / T 2 )–(1000/ T ) plots. It revealed the magnitude of barrier height. The maximum height of the potential barrier of nano-cluster TaSi x /porous silica is about 0.12–0.30 eV. The bias-temperature-stress induced leakage current was measured for reliability study.