Radiant energy – Irradiation of objects or material – Irradiation of semiconductor devices
Patent
1992-06-04
1994-04-05
Dzierzynski, Paul M.
Radiant energy
Irradiation of objects or material
Irradiation of semiconductor devices
250423R, 250424, H01J 3726
Patent
active
053007859
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention relates to apparatus for and a method of producing a beam of ions for ion implantation in a target element. The invention relates in particularly but not exclusively to apparatus for and methods of implanting ions of a preselected species, into a target element, for example the controlled introduction of a species into the surface layer of another material. The technique is important in semi-conductor technology where it is used in the manufacture of integrated circuits and other devices, particularly by modifying the conductivity of semi-conductor material by introducing chemical impurities into the material. The general background to the use of ion implantation in the manufacture of large scale integrated circuit chips is set out in published U.S. Pat. No. 4578589, having the same inventor as the present application.
An ion implantation apparatus normally consists of an ion source, an extraction system having an extraction-electrode which accelerates the ions from the extraction slot in the ion source, an analysing magnet for the selection of the required ion species, acceleration stages before or after the analysing magnet, and a target region with means for producing relative scanning movement between the beam and the target, either by scanning the beam, or by moving the target.
A number of problems arise in connection with the ion source and extraction system, particularly where the ion implantation apparatus is to be used to implant a number of different species selectively in a target. The ion source is typically a hot cathode, arc discharge, with a tungsten filament, maintained at approximately 10.sup.-2 torr pressure by a gas or vapour supply system. Such an ion source has a limited operational life time before it requires servicing, and its performance and reliability are adversely affected by using the source for a number of different species. The extraction system is typically an accelerating gap with a voltage of 10-50 kV across it. Sparking across this gap often becomes a problem when the extraction conditions are changed, particularly when the species is changed or the extraction voltage increased.
SUMMARY OF THE PRESENT INVENTION
It is an object of the present invention to overcome or reduce these difficulties, and to provide apparatus for producing an ion beam, having an increased operational lifetime, and improved provision for changing from one species to another.
In accordance with the present invention, there is provided apparatus for producing a beam of ions, comprising a plurality of ion sources, moveable support means for supporting the ion sources, a housing defining an outlet path for an ion beam produced by an ion source, and drive means for moving the support means so as to bring a selected ion source into an operating position relative to the housing to direct an ion beam along the outlet path.
The invention has particular application in apparatus for implanting ions in a target element. Such apparatus in accordance with the invention comprises, as a component, an ion producing apparatus as set out in the previous paragraph, or as set out in succeeding paragraphs, together with means for accelerating, analysing and focusing the ion beam, and for directing the beam onto a target element.
The plurality of ion sources may be moveable in a number of different configurations, for example, a linear or notary movement, but particular advantage may be obtained where the ion sources are provided in a circular configuration. Thus in one preferred form, the support means comprises rotary support means for supporting the ion sources in a circular configuration and the drive means comprises rotary drive means for rotating the support means to bring the selected ion source into the said operating position relative to the housing.
In accordance with a main preferred feature of the invention, the apparatus includes a plurality of extraction electrodes each for extracting ions from an ion source to produce an ion beam for ion implantation, s
REFERENCES:
patent: 3770870 (1973-11-01), Kervizic et al.
patent: 4151420 (1979-04-01), Keller et al.
patent: 4578589 (1986-03-01), Aitken
patent: 4914305 (1990-04-01), Benveniste et al.
patent: 4994164 (1991-02-01), Bernardet et al.
Patent Abstract of Japan, vol. 11, No. 325 (E-551) (2772) 22 Oct. 1987 & JP, A, 62 113 346 (Toshiba Corp.) 25 May 1987.
Patent Abstract of Japan, vol. 13, No. 198 (E-756) (3546) 11 May 1989 & JP, A, 1 019 659 (Minolta Camera Co.) 23 Jan., 1989.
Patent Abstract of Japan, vol. 13, No. 396 (E-815 (3744) 4 Sep. 1989 & JP, A, 1 143 124 (JEOL Ltd.) 5 Jun. 1989.
Dzierzynski Paul M.
Nguyen Kiet T.
Superion Limited
LandOfFree
Apparatus for and method of producing ion beams does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Apparatus for and method of producing ion beams, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Apparatus for and method of producing ion beams will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-513500