The surface chemical reaction induced by directly injected NO (nitric oxide) during the chemical dry etching of silicon oxide layers under the supply of F radicals generated from an F-2 remote plasma generator led to the enhancement of etch rate. The large etch rate enhancement was attributed to the effective removal of oxygen atoms from the oxide layer. The direct injection of NO into the reactor facilitates the formation of various nitrided species through surface chemical reaction of the adsorbed NO molecules with the silicon oxide layer. The NO-induced surface reactions, in turn, promote the chemical reaction of the fluorine atoms with the silicon via SiF4 formation and the resulting generation of desorbing NO, NO2, and HNO3 by-products. As a result, the effective removal of oxygen and silicon atoms from the silicon oxide surface significantly enhances the chemical dry etch rate. The process regime for the NO-induced chemical reaction and etch rate enhancement of the silicon oxide layer was extended at elevated temperature. (c) 2007 The Electrochemical Society.