Sputter ion pump having an improved magnet assembly

Abstract

A sputter ion pump ( 1 ) has an improved magnet assembly comprising primary magnets ( 9 a, 9 b ), disposed on opposite ends of the pump cells of an anode, and secondary magnets ( 11; 11′, 11″ ) disposed on one side only of the pump cells, whereby the assembly exhibits an asymmetrical configuration. The sputter ion pump with the improved magnet assembly allows for attaining high pumping speeds even at low pressures with reduced size, weight and manufacturing cost of the pump itself.

1 . A sputter ion pump ( 1 ) comprising:
 a vacuum enclosure ( 3 );   an anode located inside said vacuum enclosure and consisting of a plurality of pump cells;   a cathode located inside said vacuum enclosure and consisting of plates positioned at and spaced apart from opposite ends of said pump cells;   primary magnets ( 9   a ,  9   b ) positioned at opposite ends of said pump cells for producing a magnetic field coaxial with said pump cells; and   secondary magnets ( 11 ;  11 ′,  11 ″) disposed on one side only of said pump cells for providing an asymmetrical configuration to a magnetic assembly being formed by said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″).   
   
   
       2 . The sputter ion pump ( 1 ) as claimed in  claim 1 , wherein said secondary magnets ( 11 ;  11 ′,  11 ″) are disposed on a bottom side of said vacuum enclosure ( 3 ). 
   
   
       3 . The sputter ion pump ( 1 ) as claimed in  claim 1 , wherein two said secondary magnets ( 11 ;  11 ′,  11 ″) are provided and are arranged with opposite polarities. 
   
   
       4 . The sputter ion pump ( 1 ) as claimed in  claim 2 , wherein said secondary magnets ( 11 ;  11 ′,  11 ″) are permanent magnets. 
   
   
       5 . The sputter ion pump ( 1 ) as claimed in  claim 3 , wherein said secondary magnets ( 11 ;  11 ′,  11 ″) are permanent magnets. 
   
   
       6 . The sputter ion pump ( 1 ) as claimed in  claim 1 , wherein said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″) are housed within a substantially U-shaped bearing structure ( 13 ), which is secured to said vacuum enclosure ( 3 ). 
   
   
       7 . The sputter ion pump ( 1 ) as claimed in  claim 4 , wherein said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″) are housed within a substantially U-shaped bearing structure ( 13 ), which is secured to said vacuum enclosure ( 3 ). 
   
   
       8 . The sputter ion pump ( 1 ) as claimed in  claim 5 , wherein said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″) are housed within a substantially U-shaped bearing structure ( 13 ), which is secured to said vacuum enclosure ( 3 ). 
   
   
       9 . The sputter ion pump ( 1 ) as claimed in  claim 1 , wherein said pump ( 1 ) further comprises a plate ( 17 ) located on the side of said vacuum enclosure ( 3 ) opposite to said secondary magnets ( 11 ;  11 ′,  11 ″). 
   
   
       10 . The sputter ion pump ( 1 ) as claimed in  claim 9 , wherein said plate ( 17 ) is made of ferromagnetic material for confining the magnetic field generated by said secondary magnets ( 11 ;  11 ′,  11 ″). 
   
   
       11 . The sputter ion pump ( 1 ) as claimed  claim 2 , wherein said pump ( 1 ) further comprises a plate of ferromagnetic material ( 17 ), which is located on the side of said enclosure ( 3 ) opposite to said secondary magnets ( 11 ;  11 ′,  11 ″). 
   
   
       12 . The sputter ion pump ( 1 ) as claimed in  claim 3 , wherein said pump ( 1 ) further comprises a plate ( 17 ) of ferromagnetic material ( 17 ), which is located on the side of said vacuum enclosure ( 3 ) opposite to said secondary magnets ( 11 ;  11 ′,  11 ″). 
   
   
       13 . The sputter ion pump ( 1 ) as claimed in  claim 10 , wherein said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″) are housed within a substantially U-shaped bearing structure ( 13 ), which is secured to said vacuum enclosure ( 3 ). 
   
   
       14 . The sputter ion pump ( 1 ) as claimed in  claim 11 , wherein said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″) are housed within a substantially U-shaped bearing structure ( 13 ), which is secured to said vacuum enclosure ( 3 ). 
   
   
       15 . The sputter ion pump ( 1 ) as claimed in  claim 12 , wherein said primary magnets ( 9   a ,  9   b ) and said secondary magnets ( 11 ;  11 ′,  11 ″) are housed within a substantially U-shaped bearing structure ( 13 ), which is secured to said vacuum enclosure ( 3 ). 
   
   
       16 . The sputter ion pump ( 1 ) as claimed in  claim 13 , wherein said secondary magnets ( 11 ;  11 ′,  11 ″) are permanent magnets. 
   
   
       17 . The sputter ion pump ( 1 ) as claimed in  claim 14 , wherein said secondary magnets ( 11 ;  11 ′,  11 ″) are permanent magnets. 
   
   
       18 . The sputter ion pump ( 1 ) as claimed in  claim 15 , wherein said secondary magnets ( 11 ;  11 ′,  11 ″) are permanent magnets.