Abstract

Cathode sputtering apparatus having a hollow cathode on the magnetron principle with a cathode base (5) in which a hollow target (9) with a cylindrical sputtering surface (10) and a cylindrical outer surface is disposed. The cathode base (5) has a cooling passage (6). The target is externally surrounded by a magnet system (18) with magnet poles for the production of a rotationally symmetrical tunnel of magnetic lines of force closed on the circumference and over the sputtering surface. Outside of the space surrounded by the sputtering surface (10) there is disposed at least one anode (3, 4). A transport path for a substrate to be coated passes through the target (9) and the at least one anode.The cooling passage (6) is sealed off from the target (9) by a wall (7). Due to a narrow clearance, as soon as the target (9) reaches its operating temperature it comes in thermal contact with the wall (7). The [north] pole faces (N) of the magnet system (18) are on one side and the other [south] pole faces (S) lie on the other side of the end faces of the target (9) and radially on a radius which is equal to or greater than the radius of the sputtering surface (10). The magnet system (18) is held at a freely adjustable ("floating") potential in operation by insulating spaces (11, 19, 10).