Low-k breakdown improvement in 65nm dual-damascene Cu process

Leakage and breakdown characteristics of low-k dielectrics are becoming increasingly important reliability issues for Cu interconnects as device dimensions are scaled. Especially, in 65 nm dual-damascene Cu process, low-k dielectric has difficulty in meeting a breakdown spec of 50 V on cumulative curve at 0.1% intersection. Both dual-damascene metal dimension process uniformity control and interface integrity between Cu and NDC cap layer (SiCN) control are highly important in the 65 nm low-k dielectric breakdown reliability.