Sputtering sources for high-pressure sputtering with large targets and sputtering method

摘要

A sputtering head comprises a receiving area for a sputtering target (target receptacle). The sputtering head comprises one or more magnetic field sources so as to generate a stray magnetic field. The magnetic north and the magnetic south of at least one magnetic field source, between which the stray field forms, are located 10 mm or less, preferably 5 mm or less, and particularly preferably approximately 1 mm apart. It was found that, notably when sputtering at a high sputtering gas pressure of 0.5 mbar or more, the degree of ionization of the sputtering plasma, and consequently also the ablation rate of the sputtering target, can be locally adjusted by such a locally effective magnetic field. This allows the thicknesses of the layers that are obtained to be more homogeneous over the surface of the substrate. Advantageously, the sputtering head additionally comprises a solid state insulator, which surrounds the base body comprising the target receptacle and the sputtering target (all connected to potential) and electrically insulates the same from the shield that spatially limits the material ablation to the sputtering target (connected to ground).

主权项

1. A method for the sputter deposition of a target material on a substrate at a pressure of 0.5 to 5.0 mbar using a sputtering head comprising a sputtering target, a base body, a shield, a solid state insulator, a ferromagnetic yoke body, a plurality of ferromagnetic carrier elements, and a plurality of permanent magnets, the base body adapted as a receptacle receiving the sputtering target, the shield adapted to limit material ablation of the sputtering target, the solid state insulator arranged between the base body and the shield, the yoke body located in the base body and having a plurality of cells, each one cell of the plurality of cells comprising an axially-extending portion and a base portion, each one cell of the plurality of cells having a corresponding one of the plurality of ferromagnetic carrier elements situated therein abutting said base portion and axially-extending portion, said one ferromagnetic carrier element having a axially-extending through-hole with said corresponding one permanent magnet situated therein, the plurality of permanent magnets being spaced apart by less than 5 mm, the method comprising:
configuring the sputtering head so that each one of the plurality of permanent magnets has a common pole alignment with a common one pole of a north pole or south pole at a first end in contact with said base portion and a common other one of the north pole and south pole at an opposite second end; forming a plasma of a sputtering gas between the substrate and a surface of the target with a distance of separation between the sputtering target and the sputtering plasma being less than 1 mm; emitting electrons from the target surface in a direction of the plasma; diverting the electrons in the plasma by one or more magnetic field sources formed by said plurality of permanent magnets and corresponding plurality of carrier elements, the ferromagnetic yoke guiding magnetic field lines of said one or more magnetic field sources so that the magnetic field lines traverse from said common one pole through said base portion of a corresponding cell of said yoke body, along said axially-extending walls of said corresponding cell, through said sputtering target received at the base body, and back through said sputtering target to said common other one pole; and wherein a distance between magnetic north pole and south pole of each one of said one or more magnetic field sources spans 1 mm to less than 5 mm along which a stray field forms; and wherein the strength of said one or more magnetic field sources increases from the center toward the edge of the target surface.