Lead-free and antimony-free solder alloy, solder ball, and solder joint

Patent metadata

Field	Value
Publication number	US-12377500-B2
Application number	US-202117799575-A
Country	US
Kind code	B2
Filing date	Feb 8, 2021
Priority date	Feb 14, 2020
Publication date	Aug 5, 2025
Grant date	Aug 5, 2025

Abstract

Provided are a lead-free and antimony-free solder alloy, a solder ball, and a solder joint that have improved shear strength obtained by grain minuteness at a bonded interface and can suppress fusion failure. The lead-free and antimony-free solder alloy having an alloy composition consisting of, by mass %, 0.1 to 4.5% of Ag, 0.20 to 0.85% of Cu, 0.2 to 5.00% of Bi, 0.005 to 0.09% of Ni, and 0.0005 to 0.0090% of Ge with the balance being Sn, and the alloy composition satisfies the following relations (1) and (2): 0.013≤(Ag+Cu+Ni+Bi)×Ge≤0.027 (1), Sn×Cu×Ni≤5.0 (2). Ag, Cu, Ni, Bi, Ge, and Sn in the relations (1) and (2) each represent the contents (mass %) in the alloy composition.

First claim

The invention claimed is:

1. A lead-free and antimony-free solder alloy consisting of, by mass %,
0.1 to 4.5% of Ag,
0.20 to 0.85% of Cu,
0.2 to 5.00% of Bi,
0.005 to 0.09% of Ni,
0.0005 to 0.0045% of Ge, and
optionally one or more selected from the group consisting of Mn, Pd, Au, Pt, Cr, Fe, Co, V, Mo, and Nb each with an upper limit of 0.01% by mass %, and with the balance being Sn,
wherein the lead-free and antimony-free solder alloy satisfies the following relations (1) and (2):
0.013≤(Ag+Cu+Ni+Bi)×Ge≤0.027  relation (1)

Sn×Cu×Ni≤5.0  relation (2)

wherein Ag, Cu, Ni, Bi, Ge, and Sn in the relations (1) and (2) each represent the contents (mass %) thereof in the alloy composition.

2. A solder ball comprising the lead-free and antimony-free solder alloy according to claim 1 .

3. The solder ball according to claim 2 , having an average particle diameter of 1 to 1000 μm.

4. The solder ball according to claim 2 , having a sphericity of 0.95 or more.

5. The solder ball according to claim 2 , having a sphericity of 0.99 or more.

6. A ball grid array formed using the solder ball according to claim 2 .

7. A solder joint comprising the lead-free and antimony-free solder alloy according to claim 1 .

8. The lead-free and antimony-free solder alloy according to claim 1 , wherein the lead-free and antimony-free solder alloy satisfies the following relation (2):
0.7≤Sn×Cu×Ni≤5.0  relation (2)

wherein Cu, Ni, and Sn in the relation (2) each represent the contents (mass %) thereof in the alloy composition.

9. The lead-free and antimony-free solder alloy according to claim 1 , wherein ΔT is 100K or less.

10. The lead-free and antimony-free solder alloy according to claim 1 , wherein the Ge content is 0.0005 to 0.0040%.

Assignees

• Senju Metal Industry Co

Inventors

• Iijima Yuuki
• Yoshikawa Shunsaku
• Saito Takashi
• DEI Kanta
• MATSUFUJI Takahiro

Classifications

• H05K3/346

  Solder materials or compositions specially adapted therefor · CPC title

• C22C13/02

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

• B23K35/0244

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

• B23K3/0623

  for shaped solder piece feeding, e.g. preforms, bumps, balls, pellets, droplets · CPC title

• H05K3/34

  by soldering · CPC title