Cryogenic atomic layer etching with rare gases

Abstract

To provide a method for etching features in a substrate containing silicon at cryogenic temperatures.SOLUTION: A method includes forming an inert layer from condensation of noble gases at cryogenic temperatures on exposed surfaces, such as sidewalls of the feature, to passivate the sidewalls prior to the etching process. The method further includes flowing a fluorine-containing precursor gas into the chamber to form a fluorine-containing layer on the inert layer. The method further includes exposing the fluorine-containing layer and the inert layer to an energy source to form a passivation layer on an exposed portion of the substrate and exposing the substrate to ions to etch the substrate.SELECTED DRAWING: Figure 2

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