(19)

(11)

EP 0 650 642 A1

(12)

(43) Date of publication: 03.05.1995 Bulletin 1995/18 (21) Application number: 93916053.0 (22) Date of filing: 13.07.1993

(51) International Patent Classification (IPC):  H01L 41/ 09( . ) (86) International application number: PCT/GB1993/001456 (87) International publication number: WO 1994/002965 (03.02.1994 Gazette 1994/04)

(84) Designated Contracting States: AT BE CH DE DK ES FR GR IE IT LI LU MC NL PT SE (30) Priority: 17.07.1992 GB 19920015254 (71) Applicant: COOKSON GROUP plc London EC2V 6EQ (GB)	(72) Inventors: BUTCHER, Steven John Kidlington, Oxon OX5 1TF (GB) KINGS, Donald Harry Maguire, Grange Farm Bicester, Oxon 0X6 0DX (GB) HOBBY, James David Didcot, Oxon OX11 8TU (GB) (74) Representative: Allard, Susan Joyce, et al  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)