Polishing method for removing corner material from a semi-conductor wafer

In the polishing apparatus, the rotating corner polishing member is positioned so that its edge is aligned with the edge of the insulation film, and a pressing means applied the corner polishing member to the metal film of the periphery thereof. The metal film is removed by the rotary driven polishing member and slurry supplied to the polishing area. The metal portion penetrated in the corner formed by the side wall of the insulation film and the surface of the semi-conductor wafer substrate that is extremely difficult to be removed by the conventional removal method, can be removed substantially completely.