Solder alloy

Patent metadata

Field	Value
Publication number	US-10213879-B2
Application number	US-201615362421-A
Country	US
Kind code	B2
Filing date	Nov 28, 2016
Priority date	Nov 30, 2015
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

A solder alloy has an alloy composition consisting of, in mass %: Bi: 0.1 to 0.8%; Ag: 0 to 0.3%; Cu: 0 to 0.7%; P: 0.001 to 0.1%, with the balance being Sn. A total amount of Ag and Bi is from 0.3 to 0.8% in the alloy composition.

First claim

The invention claimed is:

1. A solder alloy for forming a fillet, the solder alloy having an alloy composition consisting of, in mass %:
Bi: 0.3 to 0.8%;
Ag: 0 to less than 0.2%; and
P: 0.001 to 0.1%,
with the balance being Sn, and
a total amount of Ag and Bi being from 0.3 to 0.8%, whereby deterioration of the alloy by thermal fatigue and fillet abnormality is suppressed.

2. A solder joint having an alloy composition consisting of, in mass %:
Bi: 0.3 to 0.8%;
Ag: 0 to less than 0.2%; and
P: 0.001 to 0.1%,
with the balance being Sn, and
a total amount of Ag and Bi being from 0.3 to 0.8%, whereby deterioration of the alloy by thermal fatigue and fillet abnormality is suppressed.

3. The solder alloy for forming a fillet according to claim 1 , wherein the alloy has a solid phase ratio at 235° C. of 0.02 vol. % or less, and a liquid phase ratio at 210° C. of 5.0 vol. % or less.

4. The solder alloy for forming a fillet according to claim 1 , wherein the fillet abnormality includes the presence of liftoff phenomenon, solder icicles, or solder bridges.

Assignees

• Senju Metal Industry Co

Inventors

• Yoshikawa Shunsaku
• NOMURA Hikaru

Classifications

• C22C13/02

  with antimony or bismuth as the next major constituent · CPC title

• C22C13/00

  Alloys based on tin · CPC title

• B23K35/262 Primary

  Sn as the principal constituent · CPC title

• B23K35/007

  at least one of the workpieces being of copper or another noble metal · CPC title