ISOTROPIC ATOMIC LAYER ETCH FOR SILICON AND GERMANIUM OXIDES

摘要

Methods for controlled isotropic etching of layers of silicon oxide and germanium oxide with atomic scale fidelity are provided. The methods make use of a reaction of anhydrous HF with an activated surface of an oxide, with an emphasis on removal of water generated in the reaction. In certain embodiments the oxide surface is first modified by adsorbing an OH-containing species (e.g., an alcohol) or by forming OH bonds using a hydrogen-containing plasma. The activated oxide is then etched by a separately introduced anhydrous HF, while the water generated in the reaction is removed from the surface of the substrate as the reaction proceeds, or at any time during or after the reaction. These methods may be used in interconnect pre-clean applications, gate dielectric processing, manufacturing of memory devices, or any other applications where accurate removal of one or multiple atomic layers of material is desired.

主权项

1. A method of controllably etching an oxide layer on a substrate, the method comprising:
(a) contacting the substrate housed in a process chamber with an active hydrogen-containing species to modify the surface of the oxide on the substrate, wherein the active hydrogen-containing species is a compound containing one or more OH groups, or a hydrogen-containing species generated in a hydrogen plasma, wherein the oxide is selected from the group consisting of silicon oxide, germanium oxide, and combinations thereof, and wherein the contacting of the substrate with the active hydrogen-containing species is performed without flowing HF into the process chamber; (b) removing non surface-bound active hydrogen species from the process chamber after the surface of the oxide is modified; (c) flowing an anhydrous HF into the process chamber after (b) without flowing an active hydrogen-containing species into the process chamber, wherein the anhydrous HF reacts with the modified surface of the oxide and wherein the reaction generates water; (d) removing the water generated in (c) from the surface of the substrate.