US Patent 10504742 Method of atomic layer etching using hydrogen plasma

A method for etching a target layer on a substrate by a dry etching process includes at least one etching cycle, wherein an etching cycle includes: depositing a carbon halide film using reactive species on the target layer on the substrate; and etching the carbon halide film using a plasma of a non-halogen hydrogen-containing etching gas, which plasma alone does not substantially etch the target layer, thereby generating a hydrogen halide as etchant species at a boundary region of the carbon halide film and the target layer, thereby etching a portion of the target layer in the boundary region.