Superior thermal stability of Ta/TaN bi-layer structure for copper metallization

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• 作者：Qi Xie ; Xin-Ping Qu ; Jing-Jing Tan ; Yu-Long Jiang ; Mi Zhou ; Tao Chen ; Guo-Ping Ru
• 关键词：Copper interconnect ; Diffusion barrier ; Thermal stability ; Ta/TaN
• 刊名：Applied Surface Science
• 出版年：2006
• 期刊代码：6_01694332
• 类别：ms
• 出版时间：30 November 2006
• 卷：253
• 期：3
• 页码：1666-1672
• 文件大小：581 K

摘要

Ta/TaN bi-layer structure is currently used in the ultra-large scale integrated circuits (ULSI) interconnect as barrier for copper because of its good adhesion to both SiO₂ and Cu wire. In this work Cu, Ta and TaN layers were prepared by sputtering technology. X-ray diffraction, Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) as well as transmission electron microscopy (TEM) were applied to characterize the thin film thermal stability and microstructure evolution. The results show that the Ta/TaN bi-layer structure has much better diffusion barrier properties than pure Ta or pure TaN film. A mechanism was proposed to explain the better thermal stability of the Ta/TaN bi-layer structure based on the correlation between TaN layer thickness and TaN crystallization kinetics. The microstructure evolution for Ta/TaN bi-layer structure during annealing was described.