Transformer coupled plasma dielectric etch for 0.25 μm technologies

Manufacturable etch processes for 0.18 μm technology TEOS bi-level contacts and vias (TEOS or TEOS/FOX/TEOS) are demonstrated in a low pressure high density reactor. Good CD control and high yields are demonstrated for structures down to 0.25 μm. In the process regimes used, the photoresist etch rate and the selectivity to underlayer are correlated with the amount of free fluorine in the plasma. The same TCP 9100 reactor can be used for low k polymer (Silk™ from Dow Chemical) etching with in situ hardmask open. A compromise between hard mask facetting and bowing has to be made unless passivating gases are added to an O₂/N₂ chemistry. For several architectures, initial results show potential integration with Cu.