Method of atomic layer etching using hydrogen plasma

A method for etching a target layer on a substrate by a dry etching process which comprises at least one etching cycle, wherein an etching cycle comprises:

• (i) depositing a carbon halide film using reactive species on the target layer on the substrate, wherein the carbon halide film and the target layer are in contact with each other;
• and
• (ii) etching the carbon halide film using a plasma of a non-halogen hydrogen-containing etching gas without etching the target layer, which plasma alone does not substantially etch the target layer, wherein a hydrogen halide is generated as a by-product of the etching of the carbon halide film as etchant species at a boundary region of the carbon halide film and the target layer, thereby chemically etching a portion of the target layer in the boundary region without a plasma other than the plasma of the non-halogen hydrogen-containing etching gas.