Large Etch Rate Enhancement by NO -Induced Surface Chemical Reaction during Chemical Dry Etching of Silicon Oxide in F2 Remote Plasmas

Abstract

The surface chemical reaction induced by directly injected (nitric oxide) during the chemical dry etching of silicon oxide layers under the supply of F radicals generated from an 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 into the reactor facilitates the formation of various nitrided species through surface chemical reaction of the adsorbed molecules with the silicon oxide layer. The -induced surface reactions, in turn, promote the chemical reaction of the fluorine atoms with the silicon via formation and the resulting generation of desorbing , , and 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 -induced chemical reaction and etch rate enhancement of the silicon oxide layer was extended at elevated temperature.