Integration of a poisoning-free dual damascene CDO film stack for 90 nm & beyond low-k BEOL

In this paper we report on the successful integration of a 90nm low-k full VIA-first dual damascene process architecture using carbon-doped-oxide (CDO) and SiC etch-stop-layer (ESL). One of the key features of the integration scheme is that the effects of photoresist poisoning have been eliminated by optimization of the low-k (k < 3.0) film stack deposition process. The mechanisms underlying photoresist poisoning have been investigated through detailed partition studies. Electrical yield and reliability data will be shown to demonstrate the performance of the overall integration approach.