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US 6,184,624 B2Granted
Ion source
AssigneeNissin Electric Co., Ltd.
InventorYutaka Inouchi
Life of this patent
Estimating the term…
Abstract
A first coil is provided at a position near the start terminal (closer to the window) of plasma chamber. A second coil is provided at a position near the end terminal thereof (plasma electrode). To adjust an ion beam current, a constant current, which is capable of developing a magnetic field greater than a resonance magnetic field, is fed to the first coil, and a second coil current is varied within a range within which it develops a magnetic field less than the resonance magnetic field.
Claims7
An ion source for an ion implanter comprising:
- a magnetron for generating a microwave;
- a waveguide for guiding the microwave;
- plasma chamber that is vacuumed, for providing a space for generating plasma;
- a microwave window for guiding the microwave into said plasma chamber while keeping a vacuum state;
- plasma electrode, provided at an outlet of said plasma chamber, for extracting an ion beam from said plasma chamber;
- an electrode system disposed following said plasma electrode;
- a first coil for generating a fixed magnetic field larger than a resonance magnetic field in the vicinity of said microwave window, said first coil being disposed surrounding said plasma chamber and near said microwave window;
- and
- a second coil, located near said plasma electrode, for developing a variable magnetic field smaller than said resonance magnetic field in a region near said plasma electrode;
- wherein an ion beam is varied by varying a second coil current of said second coil while keeping an magnetron output power at a fixed value.
7 more elements
Dependencies are inferred from the claim text.