(19)
(11) EP 1 220 289 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
14.05.2003 Bulletin 2003/20

(43) Date of publication A2:
03.07.2002 Bulletin 2002/27

(21) Application number: 01202936.9

(22) Date of filing: 02.08.2001
(51) International Patent Classification (IPC)7: H01J 49/42, H01J 49/30
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 08.08.2000 US 634665

(71) Applicant: Archimedes Technology Group, Inc.
San Diego, CA 92121 (US)

(72) Inventor:
  • Ohkawa, Tihiro
    La Jolla, California 92037 (US)

(74) Representative: Gates, Marie Christina Esther et al
c/o Tomkins & Co. 5 Dartmouth Road
Dublin 6
Dublin 6 (IE)

   


(54) Plasma mass selector


(57) A plasma mass selector for processing a partially ionized multi-species plasma includes magnetic coils that are mounted on a cylindrical chamber to establish an axially oriented uniform magnetic field in the chamber. A segmented quadrupole electrode creates a non-uniform cyclotron electric field in the chamber that is oriented perpendicular to the chamber axis to cross with the magnetic field. With the plasma in the chamber, a controller is activated to operate the non-uniform cyclotron electric field at a predetermined cyclotron frequency (ω). The electric field thus resonates with selected charged particles having the predetermined cyclotron frequency (ω) to restrain the selected particles in orbits around the central axis during their transit through the chamber. On the other hand, non-selected particles are allowed to drift radially outward from the central axis for collision with the wall and subsequent removal therefrom.






Search report