The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 18, 2000
Filed:
Nov. 12, 1997
John H Keller, Newburgh, NY (US);
Dennis K Coultas, Hopewell Junction, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An apparatus and method of producing a negative ion plasma for use in manufacturing of microelectronic devices, particularly etching of microelectronic patterns in semiconductor wafers. A negative ion plasma is produced from a hot electron plasma formed by a RF or UHF plasma source. The negative ion plasma includes positive ions, negative ions and relatively cold electrons, such electrons having an effective electron temperature or average energies less than that for maintaining the plasma. The fields producing the hot plasma are isolated from the negative ion plasma in a cold plasma region by a magnetic filter. The magnetic filter confines the plasmas to provide plasma uniformity at a work piece being etched by the negative ion plasma. The magnetic filter further prevents hot electrons originating in the hot electron plasma from diffusing into the negative ion plasma, while allowing positive ions and cold electrons to diffuse from the hot plasma to the negative ion plasma. An RF bias on the work piece accelerates the positive ions, electrons and/or negative ions to the work piece being etched.