Cylindrical AC/DC Magnetron with Compliant Drive System and Improved Electrical and Thermal Isolation

Abstract

An AC/DC cylindrical magnetron with a drive system that absorbs large variations in the rotation of the target tube, an efficient high capacity electrical transfer system, and improved electrical isolation.

1 . An endblock for holding an end of a cylindrical target tube in a cylindrical magnetron sputtering system, comprising: 
 a spindle for coupling to the end of the cylindrical target tube;    an isolation housing extending about the spindle; and    an electrically non-conductive ceramic bearing between the spindle and the isolation housing that allows the spindle to rotate within the isolation housing.    
   
   
       2 . The endblock of  claim 1  further comprising non-metallic rotational seals extending between the isolation housing and the spindle, the seals allowing rotation of the spindle within the isolation housing while maintaining a seal across a gap between the isolation housing and the spindle.  
   
   
       3 . The endblock of  claim 1  wherein the spindle is formed of 304 stainless steel.  
   
   
       4 . The endblock of  claim 1  further comprising a brush segment in contact with the spindle, the brush segment conducting electrical current from a current source to the spindle, the brush segment held in contact with the spindle by at least one spring.  
   
   
       5 . The endblock of  claim 4  further comprising at least one additional brush segment, the brush segment and the at least one additional brush segment having a semi-cylindrical shape, the at least one spring being a garter spring.  
   
   
       6 . The endblock of  claim 1  further comprising a primary housing extending about the isolation housing with forced air supplied within the primary housing.  
   
   
       7 . The endblock of  claim 6  further comprising a first shield and a_second shield, the first shield extending about the primary housing and the second shield extending about the first shield and the primary housing.  
   
   
       8 . The endblock of  claim 7  wherein the primary housing, first shield and second shield are electrically insulated from each other.  
   
   
       9 . The endblock of  claim 1  further comprising a first rotational seal and a second rotational seal extending in a radial direction between the isolation housing and the spindle to form a cavity between the first rotational seal and the second rotational seal along an axial direction, the first seal having water on a first side and the cavity on a second side, a water sensor connected to the cavity, the water sensor detecting the presence of water in the cavity.  
   
   
       10 . A cylindrical magnetron sputtering system, comprising: 
 a target tube having target material at an outer cylindrical surface, the target tube extending from a first end to a second end;    a first endblock holding the first end of the target tube; and    a second endblock holding the second end of the target tube, the second endblock including a spindle that is attached to the target tube, an isolation housing, an electrically non-conductive ceramic bearing that holds the spindle within the isolation housing allowing the spindle and target tube to rotate about an axis, and a non-metallic rotational seal extending between the spindle and the isolation housing.    
   
   
       11 . The cylindrical magnetron sputtering system of  claim 10  wherein the first endblock supplies a turning force to the first end of the target tube causing the target tube and the spindle to rotate and the second endblock supplies cooling water and electrical current to the target tube.  
   
   
       12 . The cylindrical magnetron sputtering system of  claim 11  wherein the ceramic bearing and the non-metallic seal do not provide an electrical current path between the isolation housing and the spindle.  
   
   
       13 . The cylindrical magnetron sputtering system of  claim 12  wherein the ceramic bearing and the non-metallic seal extend circumferentially about the spindle but are not subject to substantial induced current from an alternating current passing through the spindle.  
   
   
       14 . The cylindrical magnetron sputtering system of  claim 10  wherein the spindle has an area having a chromed surface.  
   
   
       15 . The cylindrical magnetron sputtering system of  claim 14  wherein the portion is formed by depositing a hard chrome layer and subsequently precision diamond lapping the chrome layer.