Lead-free solder alloy, solder joint, solder paste composition, electronic circuit board, and electronic device

Patent metadata

Field	Value
Publication number	US-10926360-B2
Application number	US-201715709424-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Mar 22, 2016
Publication date	Feb 23, 2021
Grant date	Feb 23, 2021

Abstract

According to one aspect of the present invention, a lead-free solder alloy includes 2% by mass or more and 3.1% by mass or less of Ag, more than 0% by mass and 1% by mass or less of Cu, 1% by mass or more and 5% by mass or less of Sb, 3.1% by mass or more and 4.5% by mass or less of Bi, 0.01% by mass or more and 0.25% by mass or less of Ni, and Sn.

First claim

What is claimed is:

1. A lead-free solder alloy consisting of:
2% by mass or more and 3.1% by mass or less of Ag;
more than 0% by mass and 1% by mass or less of Cu;
2% by mass or more and 5% by mass or less of Sb;
3.1% by mass or more and 4.5% by mass or less of Bi;
0.01% by mass or more and 0.03% by mass or less of Ni;
more than 0.008% by mass and 0.1% by mass or less of Co;
optionally 0.001% by mass or more and 0.05% by mass or less of at least one of P, Ga, and Ge;
optionally 0.001% by mass or more and 0.05% by mass or less of at least one of Fe, Mn, Cr, and Mo; and
Sn.

2. The lead-free solder alloy according to claim 1 ,
wherein an amount of Sb is 2% by mass to 4% by mass, and the amount of Bi is 3.1% by mass to 3.2% by mass.

3. The lead-free solder alloy according to claim 1 ,
wherein an amount of Cu is 0.7% by mass to 1% by mass.

4. The lead-free solder alloy according to claim 1 ,
wherein an amount of Cu is 0.7% by mass.

5. A solder paste composition comprising:
a powder of the lead-free solder alloy according to claim 1 ; and
a flux composition containing a base resin (A), an activator (B), a thixotropic agent (C), and a solvent (D).

6. The solder paste composition according to claim 5 , wherein in the flux composition, the amount of the activator (B) is 4.5% by mass or more and 35% by mass or less with reference to the total amount of the flux composition, and
the activator (B) is composed of a linear saturated dicarboxylic acid (B-1) having 3 to 4 carbon atoms in an amount of 0.5% by mass or more and 3% by mass or less with reference to the total amount of the flux composition, a dicarboxylic acid (B-2) having 5 to 13 carbon atoms in an amount of 2% by mass or more and 15% by mass or less with reference to the total amount of the flux composition, and a dicarboxylic acid (B-3) having 20 to 22 carbon atoms in an amount of 2% by mass or more and 15% by mass or less with reference to the total amount of the flux composition.

7. The solder paste composition according to claim 6 , wherein the linear saturated dicarboxylic acid (B-1) having 3 to 4 carbon atoms is malonic acid and/or succinic acid,
the dicarboxylic acid (B-2) having 5 to 13 carbon atoms is at least one selected from glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, 2-methylazelaic acid, sebacic acid, undecanedioic acid, 2,4-dimethyl-4-methoxycarbonyl undecanedioic acid, dodecanedioic acid, tridecane diacid, and 2,4,6-trimethyl-4,6-dimethoxycarbonyl tridecane diacid, and
the dicarboxylic acid (B-3) having 20 to 22 carbon atoms is at least one selected from eicosane diacid, 8-ethyl octadecane dioic acid, 8,13-dimethyl-8,12-eicosadiene diacid, and 11-vinyl-8-octadecene diacid.

8. An electronic circuit board comprising a solder joint to joint an electronic component with the lead-free solder alloy according to claim 1 .

9. An electronic circuit board comprising a solder joint containing the solder paste composition according to claim 5 .

10. An electronic device comprising the electronic circuit board according to claim 8 .

11. The lead-free solder alloy of claim 1 , wherein the mass ratio of Ni content relative to Co content is 1 or more and 3.75 or less.

12. A lead-free solder alloy consisting of:
2% by mass or more and 3.1% by mass or less of Ag;
more than 0% by mass and 1% by mass or less of Cu;
2% by mass or more and 5% by mass or less of Sb;
3.1% by mass or more and 4.5% by mass or less of Bi;
0.01% by mass or more and 0.03% by mass or less of Ni;
more than 0.008% by mass and 0.1% by mass or less of Co;
optionally 0.001% by mass or more and 0.05% by mass or less of at least one of P, Ga, and Ge;
optionally 0.001% by mass or more and 0.05% by mass or less of at least one of Fe, Mn, Cr, and Mo; and
Sn,
wherein inequalities (A) to (D) in terms of % by weight are satisfied,
3≤an amount of Ag+(an amount of Cu/0.5)≤5.1  (A);

3.69≤(an amount of Ag/3)+(an amount of Bi/4.5)≤2.03  (B);

5≤an amount of Ag+an amount of Sb≤8.1  (C); and

0.072≤(an amount of Ni/0.25)+(an amount of Co/0.25)≤0.52  (D).

13. The lead-free solder alloy of claim 12 , wherein the mass ratio of Ni content relative to Co content is 1 or more and 3.75 or less.

14. A solder joint formed by using a lead-free solder alloy to electrically connect electrodes, the lead-free solder alloy consisting of:
2% by mass or more and 3.1% by mass or less of Ag;
more than 0% by mass and 1% by mass or less of Cu;
2% by mass or more and 5% by mass or less of Sb;
3.1% by mass or more and 4.5% by mass or less of Bi;
0.01% by mass or more and 0.03% by mass or less of Ni;
more than 0.008% by mass and 0.1% by mass or less of Co;
optionally 0.001% by mass or more and 0.05% by mass or less of at least one of P, Ga, and Ge;
optionally 0.001% by mass or more and 0.05% by mass or less of at least one of Fe, Mn, Cr, and Mo; and
Sn.

15. The solder joint of claim 14 , wherein the mass ratio of Ni content relative to Co content is 1 or more and 3.75 or less.

16. A lead-free solder alloy consisting of:
2% by mass or more and 3.1% by mass or less of Ag;
more than 0% by mass and 1% by mass or less of Cu;
2% by mass or more and 5% by mass or less of Sb;
3.1% by mass or more and 4.5% by mass or less of Bi;
0.01% by mass or more and 0.03% by mass or less of Ni;
more than 0.008% by mass and 0.1% by mass or less of Co;
Sn; and
unavoidable impurities.

17. The lead-free solder alloy of claim 16 , wherein the mass ratio of Ni content relative to Co content is 1 or more and 3.75 or less.

Assignees

• Tamura Seisakusho Kk

Inventors

• Arai Masaya
• Nakano Takeshi
• Hori Atsushi
• Katsuyama Tsukasa
• MUNEKAWA Yurika
• Maruyama Daisuke

Classifications

• H10W72/951

  Materials of bond pads · CPC title

• H10W72/29

  Bond pads specially adapted therefor · CPC title

• H10W72/07236

  Soldering or alloying · CPC title

• H10W72/072

  of bump connectors · CPC title

• H10W72/241

  Dispositions, e.g. layouts · CPC title