(19)

(11)

EP 0 423 308 A1

(12)

(43) Date of publication: 24.04.1991 Bulletin 1991/17 (21) Application number: 90907302.0 (22) Date of filing: 27.04.1990

(51) International Patent Classification (IPC):  B06B 1/ 06( . ) H01L 41/ 45( . ) (86) International application number: PCT/GB1990/000661 (87) International publication number: WO 1990/013367 (15.11.1990 Gazette 1990/26)

(84) Designated Contracting States: AT BE CH DE DK ES FR IT LI LU NL SE (30) Priority: 03.05.1989 GB 19890010111 (71) Applicant: GEC-MARCONI LIMITED Stanmore, Middlesex HA7 4LY (GB)	(72) Inventors: HENNING, Michael, Laurence ''Ninefields'' Shepton Mallet BA4 6PY (GB) CURTIS, Allen, Charles Somerset TA 11 6SH (GB) GOOSEY, Martin, Trevor ''The Cedars'' Northampton NN5 5OA (GB) (74) Representative: Tolfree, Roger Keith, et al  The General Electric Company, p.l.c. GEC Patent Department Waterhouse Lane Chelmsford, Essex CM1 2QX Chelmsford, Essex CM1 2QX (GB)