Paper
4 September 1998 Explosive phenomenon of AlCu/TiN and W-plugs multilevel interconnect system
J. D. Yang, Chuan-Chieh A. Lin, Anthony Yen, Sen-Fu Chen, Chao-Hsin Chang, Jie-Shin Wu, J. R. Wu
Author Affiliations +
Abstract
The 'explosive phenomenon' of AlCu/TiN metal line (explosive defect) always be observed posterior to deposit oxide film by Plasma Enhanced Chemical Vapor Deposition (PECVD) and their profile look like distorted bamboo structure. From the Tunneling Electronic Microscope (TEM) analysis result and the defect distribution on the wafer, the defects were enhanced by the compressive stress of oxide film. The tungsten (W) etch back process which will remain the impurities such as sulfur (S) and fluorine (F) from the etch gas during the over-etch period has been found to cause the damage of TiN barrier layer. The explosive defect also show the strong 'F' signal not only in the AlCu metal line but on the interface between AlCu and TiN barrier layer by the Energy-Dispersive Spectrometer (EDS) analysis of TEM. In this study, the explosive defect was duplicated successfully by CF4/CHF3 chemical plasma treatment after Tungsten (W) etch back step. The more CF4/CHF3 chemical plasma treated, the more explosive defects were found. This treatment process shown that there were very strong correlation between explosive defect and fluoric impurity. Two effective methods have been demonstrated to reduce the explosive defect. The first one was Argon (Ar) plasma treatment after W etch back. This method could remove the impurity on the TiN surface. Another one was reduced the moisture on the TiN barrier metal surface. No explosive defect was observed after PECVD oxide deposited. The two methods had been proven to be useful methods to solve the explosive phenomenon on AlCu/TiN metal line without the concern of reliability.
© (1998) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
J. D. Yang, Chuan-Chieh A. Lin, Anthony Yen, Sen-Fu Chen, Chao-Hsin Chang, Jie-Shin Wu, and J. R. Wu "Explosive phenomenon of AlCu/TiN and W-plugs multilevel interconnect system", Proc. SPIE 3508, Multilevel Interconnect Technology II, (4 September 1998); https://doi.org/10.1117/12.324039
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KEYWORDS
Explosives

Metals

Tin

Etching

Oxides

Plasma enhanced chemical vapor deposition

Plasma

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