In this article, reactive ion etching (RIE) lag effect dependence on total gas flow in contact hole etching is first investigated at a high oxide etch rate using high density plasma. We used surface wave coupled plasma apparatus, which achieves a high density of over 10(11) cm(-3) and a high oxide etch rate of over 1 mu m/min. In the high gas flow etching process, a strong RIE lag is observed. However the low gas flow etching process suppresses the RIE lag. Total gas flow dominates the RIE-lag effect; and the oxygen of the etching product plays an important role for reducing the RIE-lag effect.