US 4,383,177 AGranted

Multipole implantation-isotope separation ion beam source

AssigneeInternational Business Machines Corporation

InventorsJohn H. Keller, Charles M. McKenna

Life of this patent

Estimating the term…

Loading patent…

Abstract

A plurality of magnetic pole pieces are arranged around the external wall of a high temperature plasma confining structure. The pole pieces are positioned between permanent magnets spaced from one another and the confining structure by distances calculated to produce a minimum field toward the center of the structure with an effective containing field around the periphery of the structure. The magnets and the pole pieces are cooled. An odd number of poles are employed such that the missing pole appears as a virtual pole at the extraction slit used for forming an ion beam for ion implantation. The resulting small package multipole plasma containment functions to provide higher beam current, longer source lifetime, higher voltage stability and reduces maintenance and cleaning operations, with the permanent magnets protected from high temperature and corrosive gases.

Claims9

Dependent claims

A compact, high temperatures multipole plasma containment ion beam source comprising:

an outer box formed of heat conductive metal and constituting a heat sink cooling block;
an inner, open ended box constituting a high temperature plasma confining structure;
spacer means for mounting said inner box spaced from said outer box;
a cathode and an anode within said inner box;
a plurality of magnetic pole pieces mounted within said outer box and projecting from said outer box towards said inner box;
a plurality of permanent magnets, individual ones of said permanent magnets being positioned between given magnetic pole pieces to separate pairs of said plurality of magnetic pole pieces such that said magnetic pole pieces are separated from one another and from said confining structure by distances such that a minimum magnetic field is produced toward the center of the confining structure and an effective containment field is produced around the periphery of said confining structure permitting said ion beam source to operate at high beam current intensity and high plasma density with generated heat reaching the permanent magnets being rapidly conducted therefrom by said outer box housing said magnetic pole pieces and said permanent magnets for cooling the same.

3 more elements

Dependencies are inferred from the claim text.