Etch-Byproduct Pore Sealing for Atomic-Layer-Deposited-TaN Deposition on Porous Low-$k$ Film

概要

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Porous low-$k$ and ultrathin atomic-layer-deposited (ALD)-TaN are expected to be useful materials for Cu interconnects in ULSI devices of the 45-nm technology node and beyond. One problem with integrating these into the Cu interconnect is the Ta penetration which occurs during ALD-TaN deposition. In this work, we propose a novel pore-sealing technique using an etch-byproduct that is deposited on a sidewall of the pattern during reactive-ion-etching of the stopper under the porous low-$k$. It was found that the Ta penetration is completely prevented by the etch-byproduct if the cap insulator for the porous low-$k$ is a SiC/SiO2 multilayer. Two levels of single-damascene Cu interconnects with ALD-TaN and porous low-$k$ were successfully fabricated without the penetration, and good electrical characteristics were obtained for the interconnects.
2005-10-15