Redundant anode sputtering method

Abstract

A method is provided for coating a substrate with the aid of a magnetron cathode and two electrodes which are alternately impinged upon by a positive potential and a negative potential. Also disclosed is an assembly for coating a substrate, comprising a vacuum chamber, a magnetron cathode, two electrodes, and a voltage source. A negative potential is generated at a level that is no greater than the level of the cathode potential, thus preventing the electrode that is to be cleaned from being stripped to a greater extent than the same was coated in the previous half-wave. The magnetron cathode and the electrodes are connected to the voltage source via switching elements without being galvanically such that a negative and a positive voltage generated from the voltage source can be alternatively applied to the electrodes, the level of said voltage being no greater than the cathode voltage.

1 . Method for coating a substrate by use of redundant anode sputtering of a target on a cathode of a magnetron, wherein the cathode is supplied with a cathode potential; and, besides the cathode, two electrodes are alternately supplied with a positive potential or with a negative potential, wherein the negative potential is generated at a level that is no greater than level of the cathode potential. 
     
     
         2 . Method, as claimed in  claim 1 , further comprising: generating an alternating voltage, from which the cathode potential is generated as a pulsing direct voltage without being electrically isolated; and wherein each negative half cycle of said alternating voltage is applied in an alternating manner to one electrode respectively, and a respective positive half cycle of the alternating voltage is applied to another respective electrode at a level that is decreased. 
     
     
         3 . Method, as claimed in  claim 2 , wherein a level of the negative half cycle at an electrode is decreased. 
     
     
         4 . Method, as claimed in  claim 3 , wherein the level of the potential at the electrodes is decreased in an adjustable manner. 
     
     
         5 . Method, as claimed in  claim 1 , further comprising: generating a direct voltage, which supplies in an electrically non-isolated manner the cathode with a negative direct voltage as the cathode potential, and said direct voltage supplies one electrode respectively with a negative potential and a respective other electrode with a potential, a level of which is decreased in comparison to a level of a positive potential of the direct voltage. 
     
     
         6 . Method, as claimed in  claim 1 , further comprising: generating a first direct voltage and a second direct voltage, which supplies alternatingly in an electrically non-isolated manner the cathode with a negative direct voltage as the cathode potential, and the first and second direct voltages supply one electrode respectively with a negative potential and a respective other electrode with a potential, a level of which is decreased in comparison to a level of a positive potential of the first and the second direct voltage. 
     
     
         7 . Method, as claimed in  claim 6 , wherein a level of the negative potential is decreased in comparison to a level of a negative potential of the first direct voltage and the second direct voltage. 
     
     
         8 . Method, as claimed in  claim 5 , wherein a level of the potential at the electrodes is decreased in an adjustable manner.