Solder alloy, solder paste, and electronic circuit board

Patent metadata

Field	Value
Publication number	US-2016288271-A1
Application number	US-201414442597-A
Country	US
Kind code	A1
Filing date	Aug 28, 2014
Priority date	Jun 24, 2014
Publication date	Oct 6, 2016
Grant date	—

Abstract

A solder alloy substantially consists of tin, silver, indium, bismuth, and antimony. With respect to the total amount of the solder alloy, the content ratio of the silver is 2.8 mass % or more and 4 mass % or less; the content ratio of the indium is 6.2 mass % or more and 9.0 mass % or less; the content ratio of the bismuth is 0.7 mass % or more and 5.0 mass % or less; the content ratio of the antimony is 0.3 mass % or more and 5.0 mass % or less; and the content ratio of the tin is the remaining ratio and the value of A in the discriminant (1) is 4.36 or less.
A=0.87×[In content ratio (mass %)]−0.41×[Ag content ratio (mass %)]−0.82×[Sb content ratio (mass %)]  (1)

First claim

1 . A solder alloy substantially consisting of:
tin, silver, indium, bismuth, and antimony, wherein with respect to the total amount of the solder alloy, the content ratio of the silver is 2.8 mass % or more and 4 mass % or less; the content ratio of the indium is 6.2 mass % or more and 9.0 mass % or less; the content ratio of the bismuth is 0.7 mass % or more and 5.0 mass % or less; the content ratio of the antimony is 0.3 mass % or more and 5.0 mass % or less; and the content ratio of the tin is the remaining ratio and the value of A in the following discriminant (1) is 4.36 or less, provided that the case where the content ratio of the silver is 3.2 mass %; the content ratio of the indium is 6.8 mass %; the content ratio of the bismuth is 2.3 mass %; the content ratio of the antimony is 0.9 mass %; and the content ratio of the tin is the remaining ratio is excluded
A=0.87×[In content ratio (mass %)]−0.41×[Ag content ratio (mass %)]−0.82×[Sb content ratio (mass %)]  (1).

2 . The solder alloy according to claim 1 , wherein
the content ratio of the bismuth is 1.0 mass % or more and 3.0 mass % or less.

3 . The solder alloy according to claim 1 , wherein
the content ratio of the antimony is 10 mass % or more and 3.0 mass % or less.

4 . The solder alloy according to claim 1 further comprising:
at least one element selected from the group consisting of copper, nickel, cobalt, gallium, germanium, and phosphorus, wherein
with respect to the total amount of the solder alloy, the content ratio of the element is above 0 mass % and 1 mass % or less.

5 . A solder paste comprising:
a solder powder composed of a solder alloy and flux, wherein the solder alloy substantially consists of: tin, silver, indium, bismuth, and antimony, and with respect to the total amount of the solder alloy, the content ratio of the silver is 2.8 mass % or more and 4 mass % or less; the content ratio of the indium is 6.2 mass % or more and 9.0 mass % or less; the content ratio of the bismuth is 0.7 mass % or more and 5.0 mass % or less; the content ratio of the antimony is 0.3 mass % or more and 5.0 mass % or less; and the content ratio of the tin is the remaining ratio and the value of A in the following discriminant (1) is 4.36 or less, provided that the case where the content ratio of the silver is 3.2 mass %; the content ratio of the indium is 6.8 mass %; the content ratio of the bismuth is 2.3 mass %; the content ratio of the antimony is 0.9 mass %; and the content ratio of the tin is the remaining ratio is excluded
A=0.87×[In content ratio (mass %)]−0.41×[Ag content ratio (mass %)]−0.82×[Sb content ratio (mass %)]  (1).

6 . An electronic circuit board comprising:
a soldering portion by a solder paste, wherein the solder paste comprises: a solder powder composed of a solder alloy and flux, and the solder alloy substantially consists of: tin, silver, indium, bismuth, and antimony, and with respect to the total amount of the solder alloy, the content ratio of the silver is 2.8 mass % or more and 4 mass % or less; the content ratio of the indium is 6.2 mass % or more and 9.0 mass % or less; the content ratio of the bismuth is 0.7 mass % or more and 5.0 mass % or less; the content ratio of the antimony is 0.3 mass % or more and 5.0 mass % or less; and the content ratio of the tin is the remaining ratio and the value of A in the following discriminant (1) is 4.36 or less, provided that the case where the content ratio of the silver is 3.2 mass %; the content ratio of the indium is 6.8 mass %; the content ratio of the bismuth is 2.3 mass %; the content ratio of the antimony is 0.9 mass %; and the content ratio of the tin is the remaining ratio is excluded
A=0.87×[In content ratio (mass %)]−0.41×[Ag content ratio (mass %)]−0.82×[Sb content ratio (mass %)]  (1).

7 . The solder paste according to claim 5 , wherein the solder alloy further contains at least one element selected from the group consisting of copper, nickel, cobalt, gallium, germanium, and phosphorus, and
with respect to the total amount of the solder alloy, the content ratio of the element is above 0 mass % and 1 mass % or less.

8 . The electronic circuit board according to claim 6 , wherein the solder alloy further contains at least one element selected from the group consisting of copper, nickel, cobalt, gallium, germanium, and phosphorus, and
with respect to the total amount of the solder alloy, the content ratio of the element is above 0 mass % and 1 mass % or less.

Assignees

• Harima Chemicals Inc

Inventors

• Ikeda Kazuki
• Inoue Kosuke
• Ichikawa Kazuya
• Takemoto Tadashi

Classifications

• H05K3/3465

  Application of solder · CPC title

• B23K35/262 Primary

  Sn as the principal constituent · CPC title

• C22C13/00

  Alloys based on tin · CPC title

• B23K35/025

  Pastes, creams or slurries · CPC title

• B23K2101/42

  Printed circuits · CPC title