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.

Date of Patent:
Mar. 29, 2016

Filed:

Jan. 27, 2015
Applicants:

Fuji Electric Co., Ltd., Kanagawa, JP;

Nihon Handa Co., Ltd., Tokyo, JP;

Inventors:

Mitsuo Yamashita, Tokyo, JP;

Tomoaki Goto, Tokyo, JP;

Takeshi Asagi, Tokyo, JP;

Assignees:

FUJI ELECTRIC CO., LTD., Kawasaki-Shi, JP;

NIHON HANDA CO., LTD., Tokyo, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H05K 3/34 (2006.01); B23K 1/00 (2006.01); B23K 35/02 (2006.01); B23K 35/26 (2006.01); C22C 1/04 (2006.01); C22C 12/00 (2006.01); C22C 13/00 (2006.01); C22C 28/00 (2006.01);
U.S. Cl.
CPC ...
H05K 3/341 (2013.01); B23K 1/0016 (2013.01); B23K 35/025 (2013.01); B23K 35/0244 (2013.01); B23K 35/262 (2013.01); C22C 1/0483 (2013.01); C22C 12/00 (2013.01); C22C 13/00 (2013.01); C22C 28/00 (2013.01); H05K 3/3484 (2013.01); B23K 2201/36 (2013.01); B23K 2201/42 (2013.01); H01L 2924/0132 (2013.01); H01L 2924/0133 (2013.01); H05K 2201/0266 (2013.01); H05K 2201/0272 (2013.01); H05K 2203/04 (2013.01); H05K 2203/12 (2013.01);
Abstract

A cream solder obtained by kneading an Sn—Ag—Cu alloy together with a flux, wherein the Sn—Ag—Cu alloy includes a mixture of a first powdery alloy and a second powdery alloy, the first powdery alloy is represented by an Sn—Ag phase diagram having a solid-liquid coexistence region and has a given silver amount which is larger than that in the eutectic composition (3.5 wt. % silver), and the second powdery alloy has a silver amount which is that in the eutectic composition (3.5 wt. % silver) or which is close to that in the eutectic composition and is smaller than that in the first powdery alloy. This cream solder has excellent strength and thermal stability, and satisfactory bonding properties. It is based on an inexpensive Sn—Ag—Cu solder alloy. It is suitable for use as a high-temperature-side lead-free solder material conformable to temperature gradation bonding. Also provided is a method of soldering.


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