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(11)

EP 1 466 368 A1

(12)

(43) Date of publication: 13.10.2004 Bulletin 2004/42 (21) Application number: 02708961.4 (22) Date of filing: 07.01.2002

(51) International Patent Classification (IPC)7: H01L 27/142, H01L 31/05 (86) International application number: PCT/US2002/000269 (87) International publication number: WO 2003/061013 (24.07.2003 Gazette 2003/30)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR Designated Extension States: AL LT LV MK RO SI (71) Applicant: BP Corporation North America Inc. Warrenville, Illinois 60555 (US)	(72) Inventors: OSWALD, Robert, S. Mechanicsville, VA 23116 (US) LIU, Shengzhong Mechanicsville, VA 23111 (US) (74) Representative: Ritter, Stephen David et al Mathys & Squire100 Gray's Inn Road London WC1X 8AL London WC1X 8AL (GB)