Plasma-Etching Technology With In Situ Etched-Surface Modification for Highly Reliable Low-k/Cu Dual Damascene Interconnects.

Autor: Ohtake, Hiroto, Saito, Shinobu, Tada, Munehiro, Onodera, Takahiro, Hayashi, Yoshihiro
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Zdroj: IEEE Transactions on Semiconductor Manufacturing; Nov2005, Vol. 18 Issue 4, p672-680, 9p
Abstrakt: The plasma-etching technology presented in this paper is for fabricating highly reliable Cu dual damascene inter-connects (DDI) with organic low-k film through modification of the in situ etched surface during low-k etching. Nitrogen-based plasma with oxygen and high-molecular-weight fluorocarbon gas (C > 2) chemically modifies the sidewall surface of the etched low-k film, changing it into the carbon nitride with fluorocarbon-polymer passivation from the etching gas. After wet cleaning, the fluorocarbon-polymer is removed selectively, leaving a carbon nitride modified layer (CNL) on the sidewall. The CNL has been found to suppress Cu diffusion into the low-k film. A stacked barrier structure of conventional barrier metal and CNL is expected to have high tolerance to Cu diffusion. Combining a dual-hard-mask etching sequence with the CNL modification, Cu DDIs with organic low-k film were fabricated with high yield. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index