Chemistry: electrical and wave energy – Apparatus – Coating – forming or etching by sputtering
Patent
1995-06-16
1999-01-19
Nguyen, Nam
Chemistry: electrical and wave energy
Apparatus
Coating, forming or etching by sputtering
20429807, 20429808, 20429819, 20429841, C23C 1435
Patent
active
058610880
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a magnetic field cathode for arc discharge vaporizers having an areally formed target and an arrangement associated with the targetfor generating a magnetic field which holds the arc on the target surface and has at least one ring coil and a permanent magnet.
It is above all required, above all, of magnetic field cathodes for arc discharge vaporizers, which are used in arc coating technology, that they ensure a uniform target erosion, arc stability, long term stability and the avoidance of the occurrence of target contamination during operation.
The particularly critical target contamination in practice arises in the form of thicker deposits, which are indeed visible with the naked eye, on smaller or larger area regions of the target. In the event of the occurrence of such poisoned surface areas the arc which moves on the target avoids these regions, and as a consequence of this, the target contamination increases through the formation of such thicker coatings, for example of TiN or TiCN. The occurrence of such target contamination is not reproducible and impairs the constancy of the rate of deposition, the plasma stability and also the layer characteristics and bonding characteristics in a very negative manner.
An attempt has already been made to reduce these disadvantages of magnetic field cathodes for arc discharge vaporizers in that the foot of the arc is moved over the surface of the target by means of mechanically moved magnetic field configurations or by the use of time variable magnetic fields.
A mechanical movement of the magnetic field configurations however requires a considerable degree of cost and complexity which is not tolerable in practice and leaves much to be desired with respect to the results that can be achieved, in just the same way as does the use of time variable magnetic fields, since it is not possible to ensure long term constancy, uniformity of the erosion picture and adequate stability of the arc by means of these methods and above all target contaminations cannot be precluded with highly reactive processes such as the deposition of TiCN.
The object of the invention is thus to overcome the disadvantages of known magnetic field cathodes and to provide an improved magnetic field cathode which, despite a simple construction design-wise is ideally adaptable to the respective requirements in practice and which above all ensures constancy of the rate of deposition, plasma and arc stability and the avoidance of target contaminations.
This object is satisfied in accordance with the invention essentially in that an inwardly disposed ring coil associated with the center of the target and at least one outwardly disposed ring coil associated with the peripheral region of the target are provided, and in that the inwardly disposed ring coil surrounds a permanent magnet arranged at the center of the target and, together with this permanent magnet, forms a field line concentrator.
The underlying object can also be satisfied, in particular for narrow and thus also cost-favourable cathodes in that only a single ring coil surrounding the permanent magnet is associated with the permanent magnet which is arranged at the center of the target and forms a field line concentrator; and in that the length and width dimensions of the target are at least substantially matched to the region of parallel field lines extending in the target which are generated by the ring coil and the permanent magnet.
Through the layout and the cooperation of the magnet field generating components and their positioning relative to the target one succeeds, in conjunction with a suitable choice of the current strengths and polarities, in generating a magnetic field which has the respectively desired strength, that is to say, has an ideal parallel course of the field lines from the edge regions up to the center of the target and which thus ensures that the foot of the arc which forms is not held in specific target regions while forming an erosion trace by vertical magnetic field components.
One thus succ
REFERENCES:
patent: 4401539 (1983-08-01), Abe
patent: 4622122 (1986-11-01), Landan
patent: 4724058 (1988-02-01), Morrison, Jr.
patent: 4810346 (1989-03-01), Walf et al.
patent: 4865708 (1989-09-01), Welty
patent: 4891560 (1990-01-01), Okumura
patent: 4964968 (1990-10-01), Arita
patent: 4971674 (1990-11-01), Hata
patent: 5160595 (1992-11-01), Hauzer et al.
patent: 5174875 (1992-12-01), Hurwitt et al..
patent: 5298136 (1994-03-01), Ramalingam
Nguyen Nam
VerSteeg Steven H.
W. Bloesch AG
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