MAGNET ARRAY

摘要

An electro-magnet array is described for use in a sputtering apparatus. The array comprises a magnetisable core member (2; 102) extending substantially horizontally and having magnetisable outward projections (4 to 7; 104 to 107) arranged as at least two pairs of symmetrically opposed projections projecting outwardly from the core member (2; 102). A pole member (13 to 16; 113 to 116) is associated with each projection (4 to 7; 104 to 107) and vertically displaced with respect thereto. A magnetisable coupling means (12; 112) is arranged to couple each pole piece (13 to 16; 113 to 116) magnetically to its respective projection (4 to 7; 104 to 107). A magnetising coil (8 to 11; 108 to 111) around each projection (4 to 7; 104 to 107) is arranged for producing a magnetic field aligned substantially with a horizontal axis of symmetry of its respective projection (4 to 7; 104 to 107) in dependence upon the direction of flow of electric current through the magnetising coil (8 to 11; 108 to 111). The magnetising coils (8 to 11; 108 to 111) are arranged so that, upon energisation, the magnetic field of one coil of a pair of projections (4 to 7; 104 to 107) can produce a south pole at an inward side of its respective pole piece (13 to 16; 113 to 116) while the magnetic field of the coil (8 to 11; 108 to 111) of the other projection (4 to 7; 104 to 107) of the pair produces a north pole at an inward side of its respective pole piece (13 to 16; 113 to 116). At any moment, at least two inwardly facing south poles are produced on the pole pieces (13 to 16; 113 to 116) on one side of a vertical plane of symmetry through the array (1; 101) and an equal number of inwardly facing north poles are produced on the pole pieces (13 to 16; 113 to 116) on the other side of the vertical plane of symmetry.