Versatile Aqueous Chemistry for Selective Ru or WNx Etch and Implant BARC Removal in 5- and 3-nm Applications

Ruthenium (Ru) is considered for use as a barrier-less metallization interconnect offering low effective resistivity in advanced sub-5nm semiconductor applications. A fully aqueous, environmentally friendly chemistry has been developed for effective Ru etching with broad substrate and metallization compatibilities. This alkaline oxidative chemistry is suitable for versatile etch/clean applications, including highly selective etch of SiGe, Si, Al, W, WNx and other W alloys. Its heavy hydrocarbon and residue removal capability are demonstrated as a Cu/TiN compatible, SPM alternative in multilayer PR/BARC stripping and implant BARC removal.