Profile optimization for high aspect ratio memory using an etch front metal catalyst

Abstract

A method for etching features in a silicon containing stack below a patterned mask is provided. The stack is partially etched by providing a halogen containing etch gas and forming the halogen containing etch gas into a halogen containing plasma, wherein the halogen containing plasma partially etches features with an etch front. A metal catalyst containing layer is deposited on the etch front of the features by providing a metal catalyst containing gas, forming the metal catalyst containing gas into a plasma, and selectively depositing more of the metal catalyst containing layer on the etch front and bottoms of the features than tops of the features. The features are further etched by providing a fluorine containing etch gas and forming a fluorine containing plasma, wherein the plasma selectively etches sidewalls adjacent to the etch front of the features with respect to sidewalls adjacent to tops of the features.