(19)

(11)

EP 0 998 751 A1

(12)

(43) Date of publication: 10.05.2000 Bulletin 2000/19 (21) Application number: 98937071.3 (22) Date of filing: 21.07.1998

(51) International Patent Classification (IPC)7: H01L 21/00 (86) International application number: PCT/US9815/358 (87) International publication number: WO 9905/704 (04.02.1999 Gazette 1999/05)

(84) Designated Contracting States: DE FR GB IT (30) Priority: 22.07.1997 JP 19595997 (71) Applicant: MEMC Electronic Materials, Inc. St. Peters,Missouri 63376 (US)	(72) Inventors: IKEDA, Kiyotoshi Kawachi-gum,Tochigi-prefecture 329-0607 (JP) KURODA, Kiyoshi Utsunomiya-city,Tochigi Pref. 321-0982 (JP) (74) Representative: Eyles, Christopher Thomas  W.P. THOMPSON & CO.Celcon House289-293 High Holborn London WC1V 7HU London WC1V 7HU (GB)