Alternating current rotatable sputter cathode
The present invention is an alternating current rotary sputter cathode in a vacuum chamber. The apparatus includes a housing containing a vacuum and a cathode disposed therein. A drive shaft is rotatably mounted in the bearing housing. A rotary vacuum seal is located in the bearing housing for sealing the drive shaft to the housing. An at least one electrical contact is disposed between a power source and the cathode for transmittal of an oscillating or fluctuating current to the cathode. The electrical contact between the power source and the cathode is disposed inside of the vacuum chamber, greatly reducing, and almost eliminating, the current induced heating of various bearing, seals, and other parts of the rotatably sputter cathode assembly.
1. A method of sputtering with a rotary cathode assembly comprising:
providing a rotary cathode having a cathode target and a rotatable drive shaft connectable to a drive mechanism, said rotary cathode positioned within a cathode chamber defined in part by a chamber housing having first and second ends;
providing a non-rotatable drive shaft housing connected in sealed relationship to said chamber housing and surrounding at least a portion of said rotatable drive shaft;
providing a vacuum seal surrounding said drive shaft and positioned between said rotatable drive shaft and said non-rotatable drive shaft housing;
providing a fluctuating current power to said cathode at a connection point outside of the chamber housing and electrically engaging a portion of said cathode between said first and second ends of said chamber housing by a non-rotatable, electrically conductive member extending from a power supply located outside said vacuum chamber and past said vacuum seal to said connection point, wherein said non-rotatable, electrically conductive member comprises a portion of said drive shaft housing.
2. The method of claim 1 , wherein said non-rotatable electrically conductive member is cylindrically shaped.
3. The method of claim 2 , wherein said vacuum seal has a generally cylindrical inner surface engaging said drive shaft and wherein said cylindrically shaped, non-rotatable, electrically conductive member is concentric with said cylindrical inner surface.