(19) United States
(12) Patent Application Publication (io) Pub. No.: US 2005/0258380 Al
White et al. (43) Pub. Date: Nov. 24,2005
(54) HIGH ASPECT RATIO, HIGH MASS
RESOLUTION ANALYZER MAGNET AND
SYSTEM FOR RIBBON ION BEAMS
(76) Inventors: Nicholas R. White, Manchester, MA (US); Jiong Chen, San Jose, CA (US)
DAVID PRASHKER, PC.
P.O. Box 5387
Magnolia, MA 01930 (US)
(21) Appl. No.: 11/123,924
(22) Filed: May 6, 2005
Related U.S. Application Data
(60) Provisional application No. 60/571,965, filed on May 18, 2004.
Publication Classification (51) Int. CI.7 H01J 49/20; H01J 37/317
(52) U.S. CI 250/492.21; 250/298
The present invention provides a windowframe magnet having an aligned array ol paired bedstead coils in mirror symmetry can bend a high aspect ratio ribbon ion beam through angle ol not less than about 45 degrees and not more than about 110 degrees, and can locus it through a resolving slot lor mass analysis. The long transverse axis ol the beam, which can exceed 50% ol the bend radius, is aligned with the generated magnetic field. The array ol paired bedstead coils provide tight control ol the fringing fields, present intrinsically good field uniformity, and enable a manulacture ol much lighter construction than other magnet styles conventionally in use in the ion implantation industry.
Within the system ol the present invention, the ribbon beam is refocused with low aberration to achieve high resolving power, which is ol significant value in the ion implantation industry. System size is lurther reduced by using a small ion source and a quadrupole lens to collimate the beam alter expansion and analysis. There is no fundamental limit to the aspect ratio of the beam that can be analyzed.