A new gas circulation RIE

A new gas circulation RIE has been developed. It pumps the exhausted gas still containing usable process gas into the RIE process chamber to be reused. This new gas circulation RIE showed performances of etch rate, selectivity, etching profile, and uniformity in C/sub 4/F/sub 8//CO/Ar SiO/sub 2/ etching process comparable to those for the conventional process with 50% less C/sub 4/F/sub 8/ and 80% less CO and Ar of the original input gas flow rates. It also decreased PFC emission by two thirds less in CO/sub 2/ conversion. This new gas circulation RIE is effective for the suppression of the greenhouse effect and etching process cost.