Etch Characteristics of Al[sub 2]O[sub 3] in ICP and MERIE Plasma Etchers

The etch characteristics of Al 2 O 3 films were investigated for magnetically enhanced reactive ion etching (MERIE) and inductively coupled plasma (ICP) etch systems as a function of bias power, source power, and gas chemistry. Compared to pure Ar sputtering, F-, Cl-, and Br-based plasma provided a significant chemical enhancement. Fluorine containing plasma produced higher etch rates compared to Cl and Br. The selectivity for Al 2 O 3 over other semiconductor materials is low for all of the investigated two-gas mixtures. A polymerizing C 4 F 6 chemistry provides acceptable selectivity to Si, and was used for a patterning of an Al 2 O 3 hard mask. These structures have been transferred into the Si wafer.