Filtered cathodic arc deposition method and apparatus

Abstract

An apparatus for the application of coatings in a vacuum comprising a plasma duct surrounded by a magnetic deflecting system communicating with a first plasma source and a coating chamber in which a substrate holder is arranged off of an optical axis of the plasma source, has at least one deflecting electrode mounted on one or more walls of the plasma duct. In one embodiment an isolated repelling or repelling electrode is positioned in the plasma duct downstream of the deflecting electrode where the tangential component of a deflecting magnetic field is strongest, connected to the positive pole of a current source which allows the isolated electrode current to be varied independently and increased above the level of the anode current. The deflecting electrode may serve as a getter pump to improve pumping efficiency and divert metal ions from the plasma flow. In a further embodiment a second arc source is activated to coat the substrates while a first arc source is activated, and the magnetic deflecting system for the first arc source is deactivated to confine plasma to the cathode chamber but permit electrons to flow into the coating chamber for plasma immersed treatment of the substrates. A load lock shutter may be provided between the plasma duct and the coating chamber further confine the plasma from the first arc source.

1 . An apparatus for the application of coatings in a vacuum, comprising:
 a plurality of substantially opposed cathode chamber pairs, each cathode chamber containing a cathodic arc source and being disposed along a plasma duct in communication with each of the cathode chambers and in communication with a coating chamber containing a substrate holder for mounting substrates to be coated, the substrate holder being positioned off of an optical axis of the cathodic arc source,   at least one anode associated with each cathodic arc source for generating an arc discharge,   a deflecting system for deflecting a flow of plasma through the plasma duct toward the substrate chamber, and   a plurality of magnetic isolating coils each disposed about the plasma duct between cathode chamber pairs, transversely relative to the plasma duct and relative to a direction of the cathodic arc flow through the plasma duct,   wherein when an isolating coil is activated a flow of plasma is confined by the isolating coil.   
     
     
         2 . The apparatus of  claim 1 , wherein the isolating coils can be activated independently to selectively confine the plasma within a cell formed between activated isolating coils for a selected interval. 
     
     
         3 . The apparatus of  claim 1 , wherein at least some of the cathodic arc sources are impulse cathodic arc sources. 
     
     
         4 . A method of coating an article in a coating apparatus comprising a plurality of substantially opposed cathode chambers each supporting a cathodic arc source and being disposed along an elongated plasma duct in communication with the cathode chambers, at least one anode associated with each cathodic arc source, a plurality of magnetic isolating coils each disposed transversely relative to the plasma duct between cathode chamber pairs, and a coating chamber in communication with an end of the plasma duct, the method comprising the steps of:
 a. generating an arc between the cathodic arc source and its associated anode to create a plasma of cathodic evaporate, and   b. selectively activating the isolating coil to confine the plasma within a cell formed between isolating coils for a selected interval.   
     
     
         5 . The method of  claim 4 , in which the isolating coils are activated in sequence, to raster the magnetic fields along the plasma duct. 
     
     
         6 . The method of  claim 4 , wherein at least some of the cathodic arc sources are impulse cathodic arc sources. 
     
     
         7 . The method of  claim 6 , wherein the impulse cathodic arc sources are activated in sequence along the plasma duct. 
     
     
         8 . The method of  claim 6 , wherein a directed kinetic energy of an ion component of the plasma exceeds a chaotic average kinetic energy of an electron component of the plasma. 
     
     
         9 . An apparatus for the application of coatings in a vacuum, comprising:
 at least one plasma source comprising a cathode contained within a cathode chamber,   at least one proximal anode associated with the cathode for generating an arc discharge,   a plasma duct in communication with the cathode chamber and with a coating chamber containing a substrate holder for mounting substrates to be coated, the substrate holder being positioned off of an optical axis of the cathode, and   at least one auxiliary anode disposed downstream of the plasma source for generating an auxiliary arc discharge.   
     
     
         10 . The apparatus of  claim 9 , comprising a deflecting conductor positioned adjacent to the plasma duct for generating a deflecting magnetic field for deflecting plasma from the optical axis of the cathode toward the coating chamber. 
     
     
         11 . The apparatus of  claim 10 , comprising a focusing conductor positioned adjacent to the plasma duct for generating a focusing magnetic field for focusing plasma entering the coating chamber. 
     
     
         12 . The apparatus of  claim 11 , wherein the deflecting magnetic filed and the focusing magnetic field overlap. 
     
     
         13 . The apparatus of  claim 12 , wherein the auxiliary anode is disposed near a position where a tangential component of the magnetic fields is strongest. 
     
     
         14 . The apparatus of  claim 13 , wherein the auxiliary anode comprises a generally planar conductive plate. 
     
     
         15 . The apparatus of  claim 14 , wherein the auxiliary anode comprises a plurality of baffles. 
     
     
         16 . The apparatus of  claim 13 , wherein the auxiliary anode comprises a portion substantially parallel to the optical axis of the cathode. 
     
     
         17 . The apparatus of  claim 9 , comprising a plurality of cathode chambers disposed on opposed sides of the plasma duct. 
     
     
         18 . The apparatus of  claim 9 , in which the auxiliary anode is disposed within the coating chamber. 
     
     
         19 . The apparatus of  claim 18 , in which the auxiliary anode is disposed adjacent to the substrate holder opposite the plasma duct. 
     
     
         20 . The apparatus of  claim 18 , in which a plurality of auxiliary anodes are disposed within the coating chamber. 
     
     
         21 . The apparatus of  claim 20 , in which the auxiliary anodes are disposed adjacent to walls of the coating chamber. 
     
     
         22 . The apparatus of  claim 21 , in which one or more auxiliary anodes is associated with a magnetic deflecting coil adjacent to the anode.