Apparatus for treating a substrate
This invention relates to an apparatus ( 1 ) for treating, e.g. coating, a substrate ( 35, 39 ) in a vacuum chamber ( 2 ). In this vacuum chamber ( 2 ) there are arranged n cathodes ( 7 - 10 ) and n+1 anodes ( 28 - 32 ), each of said anodes adjacent to a cathode ( 7 - 10 ). Each of the n cathodes ( 7 - 10 ) and n of the assigned anodes ( 29 - 32 ) are connected to a power supply ( 11 - 14 ). One of the anodes ( 28 ) not being assigned to a cathode ( 7 - 10 ) is connected to an electrical line ( 63 ) which is connecting each of the anodes ( 28 - 32 ). A pull-down resistor ( 34 ) is connected to said line ( 63 ) at its one end and to ground ( 33 ) at its other end.
1. Apparatus for coating a substrate comprising:
1.1 a vacuum chamber ( 2 );
1.2 n cathodes ( 7 - 10 ) inside said vacuum chamber ( 2 ), wherein n≧2, and wherein n is the number of cathodes;
1.3 at least three anodes ( 28 - 32 ) inside said vacuum chamber ( 2 );
1.4 a single connecting line ( 63 ) to which each of said anodes ( 28 - 32 ) is electrically connected;
1.5 a resistor ( 34 ) being connected to said connecting line ( 63 ) at its one end and being connected to ground ( 33 ) at its other end, said resistor ( 34 ) having a resistance of at least 2Ω.
2. Apparatus according to claim 1 , characterized in that n cathodes ( 7 - 10 ) and n+1 anodes are provided.
3. Apparatus according to claim 1 , characterized in that the vacuum chamber ( 2 ) is electrically connected to said ground ( 33 ).
4. Apparatus according to claim 1 , characterized in that each of the cathodes ( 7 - 10 ) is assigned an anode ( 29 - 32 ), and each of the cathodes ( 7 - 10 ) and its assigned anode ( 29 - 32 ) are connected to a common electrical power source ( 11 - 14 ), so that each of said cathodes ( 7 - 10 ) and assigned anodes ( 29 - 32 ) may be operated electrically independently from the other cathodes and assigned anodes.
5. Apparatus according to claim 1 , characterized in that each of the cathodes ( 7 - 10 ) comprises a planar target.
6. Apparatus according to claim 1 , characterized in that each of the cathodes ( 7 - 10 ) comprises a cylindrical target.
7. Apparatus according to claim 6 , characterized in that the resistor ( 34 ) has a resistance of 40Ω to 10 kΩ.
8. Apparatus according to claim 1 , characterized in that shrouds ( 53 , 54 ) are arranged inside the chamber ( 2 ).
9. Apparatus according to claim 1 , characterized in that the resistor ( 34 ) is a pull-down resistor.
10. Apparatus according to claim 7 , characterized in that the resistance of the resistor ( 34 ) is between 400 and 500Ω.
11. Apparatus according to claim 1 , characterized in that the cathodes are planar cathodes.
12. Apparatus according to claim 1 , characterized in that the cathodes are tubular cathodes.