(19)

(11)

EP 0 550 677 A1

(12)

(43) Date of publication: 14.07.1993 Bulletin 1993/28 (21) Application number: 91919004.0 (22) Date of filing: 24.09.1991

(51) International Patent Classification (IPC):  H05H 1/ 00( . ) (86) International application number: PCT/US1991/006962 (87) International publication number: WO 1992/006574 (16.04.1992 Gazette 1992/09)

(84) Designated Contracting States: DE FR GB (30) Priority: 28.09.1990 US 19900590198 (71) Applicant: SEMATECH, INC. Austin, TX 78741-6499 (US)	(72) Inventor: ANDERSON, Richard, L. Austin, TX 78746 (US) (74) Representative: Weber, Otto Ernst, Dipl.-Phys.  Weber & Heim Hofbrunnstrasse 36 D-81479 München D-81479 München (DE)