Novel solution for polymer and capping layer removing with wet dipping in hk metal gate etching process

A method for making metal gate stacks of a semiconductor device comprising:

• forming various gate material layers on a substrate including a high k dielectric material layer, a capping layer on the high k dielectric material layer, a metal layer on the capping layer, and a polysilicon layer on the metal layer;
• applying a first etching process to the substrate through openings of a patterned mask layer defining gate regions to remove the polysilicon layer and the metal gate layer from the openings;
• applying a solution to the substrate, the solution including diluted hydrofluoric acid (HF) and hydrochloride (HCl) to remove polymeric residue and the capping layer;
• and
• thereafter applying a second etching process to the substrate to remove the high k dielectric material layer.

A method for making metal gate stacks of a semiconductor device comprising:

• applying a first etching process to a substrate to remove a metal gate layer on the substrate;
• applying diluted hydrofluoric acid (HF) to the substrate to remove residues remaining from the first etching process;
• thereafter applying a wet etching solution to the substrate to remove a lanthanum oxide (LaO) layer;
• and
• applying a second etching process to the substrate to remove a high k dielectric material layer.