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PING XU & SUDHA S. RATHI, Applied Materials, Santa Clara, CA, USA

ABSTRACT

Alow-k dielectric barrier/etch stop film, called BLOk™, has been developed for use in copper damascene processes. This silicon carbide film is deposited using trimethylsilane ((CH3)3SiH) and has a lower dielectric constant (k < 5) than that of conventional SiC films (k > 7) generated by SiH4 and CH4, and that of plasma silicon nitride (k > 7). Characterisation of the film, including physical, electrical, and copper diffusion barrier properties, and etch selectivity, shows that this film is a good barrier/etch stop for low-k copper damascene applications. Its low dielectric constant enables a significant reduction in the effective k value of the completed dielectric stack in damascene devices.