Titanium-Nitride Removal

A method of removing a metal hard mask and etching residues from a microelectronic device comprising steps of:

• etching a trench in an interconnect structure selective to a dielectric capping layer by a reactive ion etching process (RIE);
• applying a wet chemical composition for removing at least a portion of layers on the interconnect structure selective to a dielectric hard mask layer, said chemical composition comprising an oxidizing agent selected from a group comprised of peroxides and oxidants which do not leave a residue and do not adversely attack copper, a pH controlling agent selected from a group comprised of quaternary ammonium salts and quaternary ammonium alkali, and an aqueous solution, wherein the composition has a pH in the range of about 7 to about 14;
• and
• etching the interconnect structure to open the dielectric capping layer above a copper device layer for filling the trench.