The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 24, 1999
Filed:
Oct. 28, 1997
Tetsuya Nakatsuka, Yokohama, JP;
Tasao Soga, Fujisawa, JP;
Hanae Shimokawa, Kamakura, JP;
Kenichi Yamamoto, Yokohama, JP;
Masahide Harada, Yokohama, JP;
Yuuji Ochiai, Tokyo, JP;
Tsuneaki Kamei, Kanagawa-ken, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
Provided is a lead-free solder for connecting LSI and parts on organic substrates, which can provide soldering at a maximum temperature of 220.degree.-230.degree. C. and which has a sufficient reliability in mechanical strength even at a high temperature of 150.degree. C. Also provided are electronic products prepared using this lead-free solder. The lead-free solder has a solder composition including 3-5% Zn and 10-23% Bi, the balance being Sn. Preferably, the solder composition is a composition (Sn, Zn, Bi) surrounded by lines connecting A and B, B and C and C and A, where A is (85, 5, 10 ), B is (72, 5, 23) and C is (76, 3, 21), of a ternary diagram having pure Sn, pure Zn and pure Bi at the vertices of an equilateral triangle. Through use of this solder, it is possible to solder parts, etc. on conventionally employed organic substrates at reflow temperatures equivalent to those for conventional Pb--Sn eutectic solders. The solder does not damage the environment, can be stably supplied and is low in cost.