Patent ID: 7309449

Claim:
A substrate processing method comprising: providing a substrate prepared by forming interconnect recesses in an insulating film provided in a surface of the substrate and depositing a barrier metal film and a copper film in this order on the surface; removing the copper film on the surface of the substrate so that copper substantially remains only within the interconnect recesses; and removing and flattening the copper film and the barrier metal film on the surface of the substrate by performing chemical etching with an etching liquid which etches the barrier metal film at a higher etching rate than the copper film and without applying a mechanical load to the copper film and the barrier metal film during said removing and flattening; wherein the barrier metal film is composed of tantalum nitride and/or tantalum, or titanium nitride and/or titanium, and the etching liquid contains hydrofluoric acid, an oxidizing agent and a chloride, the etching liquid having a mixing ratio between the hydrofluoric acid and the oxidizing agent such that the barrier metal film is etched at a higher etching rate than the cooper film in said removing and flattening.