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US006310372B1
(12) United States Patent ao) Patent No.: us 6,310,372 Bi
Katayama et al. (45) Date of Patent: Oct. 30,2001
(75) Inventors: Shigenori Katayama; Masahiro Yasukawa, both of Chino (JP)
(73) Assignee: Seiko Epson Corporation, Tokyo (JP)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/532,017
(22) Filed: Mar. 21, 2000
Related U.S. Application Data
(62) Division of application No. 09/219,708, filed on Dec. 23, 1998, now Pat. No. 6,066,860.
(30) Foreign Application Priority Data
Dec. 25, 1997 (JP) 9-358622
(51) Int. CI.7 H01L 27/01; H01L 27/12;
H01L 31/0392
(52) U.S. CI 257/291; 257/350; 250/332;
250/370.08; 250/370.14
