Solder alloy, solder paste, and electronic circuit board

Patent metadata

Field	Value
Publication number	US-9956649-B2
Application number	US-201414442597-A
Country	US
Kind code	B2
Filing date	Aug 28, 2014
Priority date	Jun 24, 2014
Publication date	May 1, 2018
Grant date	May 1, 2018

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 is 4.36 or less wherein A=0.87×[In content ratio (mass %)]−0.41×[Ag content ratio (mass %)]−0.82×[Sb content ratio (mass %)].

First claim

The invention claimed is:

1. A solder alloy consisting essentially 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 1.0 mass % or more and 5.0 mass % or less;
the content ratio of the antimony is 1.0 mass % or more and 5.0 mass % or less; and
the content ratio of the tin is the remaining ratio, and
wherein the value of A in the following 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), and

wherein the solder alloy satisfies:
1) Phase Transformation ranking of A or B, wherein ranking A corresponds to A: deformation of the solder alloy was not confirmed, and ranking B corresponds to B: deformation of the solder alloy was confirmed, but a bridge between solder alloys of lands that were adjacent to each other was not confirmed;
2) a Durability of a 3216 size ranking of A, wherein ranking A corresponds to A: a proportion of a crack was 70% or less of a total length of a fillet; and
3) a Breakage of Component ranking of A or B, wherein ranking A corresponds to A: a crack did not occur in a component electrode, and ranking B corresponds to B: a crack occurred in a component electrode, but rupture did not occur.

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 1.0 mass % or more and 3.0 mass % or less.

4. A solder alloy consisting essentially of:
tin, silver, indium, bismuth, antimony, and 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 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 1.0 mass % or more and 5.0 mass % or less;
the content ratio of the antimony is 1.0 mass % or more and 5.0 mass % or less;
the content ratio of the element is above 0 mass % and 1 mass % or less; and
the content ratio of the tin is the remaining ratio, and
wherein the value of A in the following 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), and

wherein the solder alloy satisfies:
1) Phase Transformation ranking of A or B, wherein ranking A corresponds to A: deformation of the solder alloy was not confirmed, and ranking B corresponds to B: deformation of the solder alloy was confirmed, but a bridge between solder alloys of lands that were adjacent to each other was not confirmed;
2) a Durability of a 3216 size ranking of A, wherein ranking A corresponds to A: a proportion of a crack was 70% or less of a total length of a fillet; and
3) a Breakage of Component ranking of A or B, wherein ranking A corresponds to A: a crack did not occur in a component electrode, and ranking B corresponds to B: a crack occurred in a component electrode, but rupture did not occur.

5. A solder paste comprising:
a solder powder composed of the solder alloy according to claim 1 , and
a flux.

6. An electronic circuit board comprising:
a soldering portion by the solder paste according to claim 5 .

Assignees

• Harima Chemicals Inc

Inventors

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

Classifications

• H05K3/3465

  Application of solder · CPC title

• H05K3/3457

  Electricity · mapped topic

• B23K35/3612

  with organic compounds as principal constituents · CPC title

• B23K35/362

  Selection of compositions of fluxes (B23K35/365, B23K35/368 take precedence) · CPC title

• B23K35/0244

  Powders, particles or spheres; Preforms made therefrom · CPC title