Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Patent
1997-04-29
1998-07-14
Berman, Jack I.
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
250398, H01J 3710, H01J 37317
Patent
active
057808635
ABSTRACT:
An electrostatic triode lens (36) is provided for use in an ion implantation system (10). The lens includes a terminal electrode (37) and an adjustable lens subassembly (40) comprising a suppression electrode (38) and a resolving electrode (39), each having matched curved surfaces (108, 110). The lens subassembly is positioned near the terminal electrode where the beam has a minimal waist in a first (dispersive) plane. Such positioning minimizes the required gaps between electrodes, and thus, helps minimize beam blow-up and the electron depletion region in the deceleration mode of operation. The suppression and resolving electrodes each have first and second portions (38A and 38B, 39A and 39B) separated by a gap (d38, d39). A movement mechanism (60, 62) simultaneously moves the first portions of the suppression and resolving electrodes (38A, 39A) toward and away from the second portions of the suppression and resolving electrodes (38B, 39B), respectively, to adjust the gaps (d38, d39) therebetween. The adjustable lens subassembly (40) conditions the beam output by the terminal electrode (37) by (i) variably focusing the beam in mutually orthogonal (dispersive and non-dispersive) planes in a deceleration mode of operation (where mass resolution is less critical), while (ii) permitting variable mass resolution in the dispersive plane in an acceleration mode of operation (where focusing is less critical). Generally, the gap (d39) between the resolving electrode pair (39) is adjusted to permit adjustable mass resolution in the dispersive plane in the acceleration mode of operation. In the deceleration mode of operation, adjustment of the gap (d39) provides adjustable dispersive plane focusing, while the voltage on suppression electrode (38) is adjusted to permit adjustable non-dispersive plane beam focusing.
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Benveniste Victor M.
Kellerman Peter L.
Berman Jack I.
Eaton Corporation
Kastelic John A.
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