Rectangular filtered vapor plasma source and method of controlling vapor plasma flow

Abstract

The invention provides an arc coating apparatus having a steering magnetic field source comprising steering conductors ( 62, 64, 66, 68 ) disposed along the short sides ( 32 c, 32 d ) of a rectangular target ( 32 ) behind the target, and a magnetic focusing system disposed along the long sides ( 32 a, 32 b ) of the target ( 32 ) in front of the target which confines the flow of plasma between magnetic fields generated on opposite long sides ( 32 a, 32 b ) of the target ( 32 ). The plasma focusing system can be used to deflect the plasma flow off of the working axis of the cathode. Each steering conductor ( 62, 64, 66, 68 ) can be controlled independently. In a further embodiment, electrically independent steering conductors ( 62, 64, 66, 68 ) are disposed along opposite long sides ( 32 a, 32 b ) of the cathode plate ( 32 ), and by selectively varying a current through one conductor, the path of the arc spot shifts to widen the erosion corridor. The invention also provides a plurality of internal anodes, and optionally a surrounding anode for deflecting the plasma flow.

1 . A vacuum arc coating apparatus comprising 
 at least one rectangular cathode plate having opposed long sides connected to a negative pole of a current source, the at least one cathode plate having a target surface comprising an evaporation surface or a sputtering surface, or both,    a coating chamber in communication with the target surface,    a substrate holder within the coating chamber,    at least one anode spaced from the target surface, connected to a positive pole of a current source, and    a magnetic deflecting system comprising at least first and second conductors arranged along opposite long sides of the at least one cathode plate, the first conductor carrying a current in a direction opposite to a direction of current in the second conductor, the first and second conductors each being disposed in front of and in the vicinity of the target surface so that a magnetic field generated thereby focuses a flow of vapour plasma from the target surface toward the substrate holder, the first conductor being electrically independent of the second steering conductor,    wherein by varying a level of current applied through the first conductor relative to the second conductor the flow of vapor plasma shifts toward the coating chamber.    
   
   
       2 . The apparatus of  claim 1  further comprising an arc igniter for igniting an arc between the at least one cathode and anode and generating at least one arc spot on the target surface.  
   
   
       3 . The apparatus of  claim 1  wherein the first and second conductors are oriented substantially parallel to the long sides of the at least one cathode plate.  
   
   
       4 . The apparatus of  claim 3  wherein steering conductors are provided along short sides of each of the at least one cathode plates.  
   
   
       5 . The apparatus of  claim 1  wherein the cathode plate is part of an arc source.  
   
   
       6 . The apparatus of  claim 5  wherein the cathode plate is part of a magnetron source.  
   
   
       7 . The apparatus of  claim 6  wherein the cathode plate Is disposed out of optical alignment with the substrate holder.  
   
   
       8 . The apparatus of  claim 7  further comprising an ionizer for ionizing the plasma flow.  
   
   
       9 . The apparatus of  claim 8  wherein focusing conductors are provided along the long sides of the cathode plate to deflect a flow of plasma from the cathode plate to the substrate holder.  
   
   
       10 . The apparatus of  claim 4  wherein adjacent to each of said at least one cathode plates are provided a plurality of pairs of steering conductors parallel to the short sides of each of said at least one cathode plates and having opposite polarities, to shift arc spots toward a long side of each of said at least one cathode plates both at the ends of the one cathode plate.  
   
   
       11 . The apparatus of  claim 1  wherein each of said at least one anode has an associated shield covering an area of the at least one cathode in which arc spots are likely to stagnate.  
   
   
       12 . The apparatus of  claim 1  further comprising at least one anode surrounding the substrate holder.  
   
   
       13 . The apparatus of  claim 12  wherein the coating chamber or a portion thereof is grounded to form an anode.  
   
   
       14 . A vacuum are coating apparatus comprising 
 at least one magnetron arc sore comprising at least one rectangular cathode plate having opposed long sides, connected to a negative pole of a current sources and sets of magnets disposed behind the at least one cathode plate, the at least one cathode plate having a target surface comprising an evaporation surface or a sputtering surface, or both, wherein said at least one magnetron arc source creates an arch-shaped magnetic field having magnetic field lines projecting above said target surface,    an anode,    a coating chamber in communication with the target surface and a housing,    a substrate holder within the coating chamber,    a plasma guide disposed between the at least one cathode plate and the coating chamber, the cathode plate being out of optical alignment with the substrate holder, and    a set of first focusing conductors disposed in front of and generally parallel to the long sides of the at least one cathode plate, for creating a half-cusp configuration of focusing magnetic field lines converging in front of the target surface along the long sides to extract plasma from the arch-shaped magnetron magnetic fields and direct the plasma toward the coating chamber.    
   
   
       15 . The apparatus of  claim 14  further comprising steering conductors disposed behind and generally parallel to short sides of the at least one cathode plate.  
   
   
       16 . The apparatus of  claim 15  wherein the sets of magnets are movable away from the at least one cathode plate.  
   
   
       17 . The apparatus of  claim 16  wherein the sets of magnets are mounted on a magnet plate mounted on a movable shaft,  
   
   
       18 . The apparatus of  claim 14  further comprising a high current low voltage arc power supply for supplying a negative voltage to the at least one cathode plate, and an arc igniter, for use of the apparatus in a cathodic arc evaporation mode.  
   
   
       19 . The apparatus of  claim 14  further comprising a cathode-ionizer out of optical alignment with the anode, for ionizing the plasma.  
   
   
       20 . The apparatus of  claim 19  wherein the cathode-ionizer is contained within a cathode chamber containing an arc source and a magnetron source is disposed it the coating chamber.  
   
   
       21 . The apparatus of  claim 19  wherein the cathode-ionizer is contained within the coating chamber and a magnetron source is disposed in a cathode chamber.  
   
   
       22 . The apparatus of  claim 14  comprising a plurality of cathode plates, wherein a magnetron arc source is associated with each cathode plate.  
   
   
       23 . A vacuum arc coating apparatus comprising 
 at least one magnetron arc source comprising at least one rectangular cathode plate having opposed long sides, connected to a negative pole of a current source, and sets of magnets disposed behind the at least one cathode plate, the at least one cathode plate having a target surface comprising an evaporation surface or a sputtering surface, or both, wherein said at least one magnetron arc source creates a magnetron magnetic field having magnetic field lines projecting above said target surface,    an anode,    a coating chamber in communication with the target surface,    a substrate holder within the coating chamber,    a plasma guide disposed between the at least one cathode plate and the coating chamber,    at least one filtered cathodic arc source out of optical alignment with the substrate holder and adjacent to the at least one magnetron arc source,    the at least one cathode plate being disposed in the plasma guide, a north pole of the magnetron magnetic field being located at the exit of the filtered arc source and a south pole of the magnetron magnetic field being located generally centrally relative to the magnetron, or a south pole of the magnetron magnetic field being located at the exit of the filtered arc source and a north pole of the magnetron magnetic field being located generally centrally relative to the magnetron, whereby magnetic field lines exiting from the filtered arc source Teach the evaporation surface, and    a set of conductors disposed in front of and generally parallel to the long sides of the target surface, for creating focusing magnetic field lines to magnetically couple the magnetron arc source to the filtered arc source and thereby extract plasma from the magnetron and the filtered cathodic arc source and direct the plasma toward the coating chamber.    
   
   
       24 . The apparatus of  claim 23  comprising a filtered arc source on both sides of said at least one magnetron arc source.  
   
   
       25 . The apparatus of  claim 23  further comprising surface conductors disposed behind of and generally parallel to short sides of said at least one cathode plate.  
   
   
       26 . The apparatus of  claim 23  in which the at least one magnetron arc source comprises at least end magnets disposed adjacent to ends of the at least one cathode plate, side magnets disposed adjacent to sides of the at least one cathode plate and a central magnet disposed adjacent to a center of the at least one cathode plate forming a generally rectangular plasma ring between the edge magnets, the central magnet and the end magnets, wherein a magnetron plasma discharge is substantially confined by arch-shaped magnetron magnetic fields in the vicinity of the at least one cathode plate  
   
   
       27 . The apparatus of  claim 23  further comprising an arc igniter for igniting an arc between the at least one cathode plate and at least one anode to generate arc spots on the evaporation surface.  
   
   
       28 . The apparatus of  claim 23  further comprising a cathodeionizer out of optical alignment with the anode, for iodizing the plasma.  
   
   
       29 . The apparatus of  claim 28  wherein the cathode-ionizer is contained within a cathode chamber containing an arc source and a magnetron source is disposed in the coating chamber,  
   
   
       30 . The apparatus of  claim 28  wherein the cathode-ionizer is contained within the coating chamber and a magnetron source is disposed in a cathode chamber.  
   
   
       31 . The apparatus of  claim 28  wherein the cathode-ionizer comprises a thermonic cathode.  
   
   
       32 . The apparatus of  claim 28  wherein the cathode-ionizer comprises a hollow cathode.  
   
   
       33 . The apparatus of  claim 28  wherein the cathode-ionizer comprises a cold vacuum arc cathode.  
   
   
       34 . The apparatus of  claim 23  wherein the coating chamber or a portion thereof is grounded to form an anode.  
   
   
       35 . A method of controlling a flow of plasma in a vacuum arc coating apparatus comprising at least one magnetron arc source comprising at least one rectangular cathode plate having opposed long sides and connected to a negative pole of a current source and having a target surface comprising an evaporation surface or a sputtering surface, or both, an anode, and a coating chamber in communication with the target surface containing a substrate holder comprising the steps of: 
 a. generating at least one cathode spot on the target surface to create a plasma, and    b. generating a deflecting magnetic field having deflecting magnetic field lines overlapping with magnetron magnetic field lines generated by said at least one magnetron arc source, the deflecting magnetic field lines and the magnetron magnetic field lines having the same transverse direction,