Method and apparatus for modifying a ribbon-shaped ion beam

A method of generating a high current, high energy ribbon-shaped beam of ions for implantation, comprising the steps of:

• a) extracting ions from an ion source to provide an extracted ion beam having a first energy and forming a ribbon-shaped beam having said first energy of said ions for implantation, said ribbon-shaped beam having an elongate cross-section normal to a beam direction, wherein at any position along said ribbon-shaped beam an orthogonal (x, y, z) Cartesian co-ordinate system is defined in which a z-axis of the co-ordinate system extends in the beam direction at a center line of said ribbon-shaped beam, an x-axis extends in a long direction of said elongate cross-section of said ribbon-shaped beam and a y-axis extends in a short direction of said elongate cross-section;
• and
• b) accelerating said ribbon-shaped beam from said first energy to a second energy, wherein said ribbon-shaped beam is accelerated to said second energy by directing said ribbon-shaped beam through an acceleration assembly containing a plurality of apertured electrodes biased to provide an electrostatic accelerating field along an axis of said assembly, said assembly including an entrance plate having a beam defining aperture slot on said axis to receive said ribbon-shaped beam, said aperture slot having a long dimension which is linear;
• wherein, at a position in front of said entrance plate, a magnetic field is generated extending in an x-direction along said x-axis of said ribbon-shaped beam to apply selected y-deflections about said x-axis to ions of said ribbon-shaped beam, to direct said ribbon-shaped beam through said aperture slot.

Apparatus for generating a high current, high energy ribbon-shaped beam of ions for implantation, comprising:

• an ion source and ion extraction optics to provide a ribbon-shaped beam of ions for implantation having a first energy, said ribbon-shaped beam having an elongate cross-section normal to a beam direction, wherein at any position along said ribbon-shaped beam an orthogonal (x, y, z) Cartesian co-ordinate system is defined in which a z-axis of the co-ordinate system extends in the beam direction at a center line of said ribbon-shaped beam, an x-axis extends in a long direction of said elongate cross-section of said ribbon-shaped beam and a y-axis extends in a short direction of said elongate cross-section;
• an acceleration assembly having an axis and containing a plurality of apertured electrodes adapted to be biased to provide an electrostatic accelerating field along said axis of said assembly, said acceleration assembly including an entrance plate having a beam defining aperture slot on said axis to receive said ribbon-shaped beam, said aperture slot having a long dimension which is linear;
• a magnetic field device located in front of said entrance plate, said magnetic field device having an opening with x and y orthogonal dimensions to accommodate said ribbon-shaped beam passing said device through said opening with the x-axis of the beam extending in said x dimension, said magnetic field device having electric coil structures adapted, when selectively energized, to provide a magnetic field in said opening in an x-direction along said x dimension of said opening so as to apply selected y-deflections about said x-axis of ions of said ribbon-shaped beam, to direct said ribbon-shaped beam through said aperture slot;
• and
• programmable power supplies connected to deliver predetermined currents to windings of said electric coil structures, wherein said programmable power supplies are arranged to deliver said predetermined currents such as to energize said coil structures to provide said x-direction magnetic field.