Lead-free solder ball

Patent metadata

Field	Value
Publication number	US-9527167-B2
Application number	US-201214005948-A
Country	US
Kind code	B2
Filing date	Mar 28, 2012
Priority date	Mar 28, 2011
Publication date	Dec 27, 2016
Grant date	Dec 27, 2016

Abstract

A lead-free solder ball for electrodes of a BGA or CSP comprising 0.5-1.1 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, and a remainder of Sn. Even when a printed circuit board to which the solder ball is bonded has Cu electrodes or Au-plated or Au/Pd-plated Ni electrodes, the solder ball has good resistance to drop impacts. The composition may further contain at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass % or at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

First claim

The invention claimed is:

1. A lead-free solder ball which is used for electrodes by mounting on a module substrate for a BGA or CSP and which has a solder composition consisting of 0.5-1.1 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, optionally at least one element selected from Fe, Co, Pt, Bi, In, Sb, P, and Ge, and a remainder of Sn.

2. The lead-free solder ball according to claim 1 , wherein the solder composition consists of 0.9-1.1 mass % of Ag, 0.7-0.8 mass % of Cu, 0.05-0.08 mass % of Ni, optionally at least one element selected from Fe, Co, Pt, Bi, In, Sb, P, and Ge, and a remainder of Sn.

3. The lead-free solder ball according to claim 1 , wherein the solder composition consists of 1.0 mass % of Ag, 0.75 mass % of Cu, 0.07 mass % of Ni, optionally at least one element selected from Fe, Co, Pt, Bi, In, Sb, P, and Ge, and a remainder of Sn.

4. The lead-free solder ball according to claim 1 , wherein the solder composition contains at least one element selected from Fe, Co, and Pt in a total amount of 0.003-0.1 mass %.

5. The lead-free solder ball according to claim 1 , wherein the solder composition contains at least one element selected from Bi, In, Sb, P, and Ge in a total amount of 0.003-0.1 mass %.

6. The lead-free solder ball according to claim 1 , wherein the solder ball has a diameter of at least 0.1 mm.

7. The lead-free solder ball according to claim 1 , wherein the solder ball has a diameter of at least 0.3 mm.

8. The lead-free solder ball according to claim 1 , wherein the solder ball has a diameter of at least 0.5 mm.

9. The lead-free solder ball according to claim 1 , wherein the solder ball is bonded to an electrode of a module substrate.

10. The lead-free solder ball according to claim 1 , wherein the solder ball is bonded to an electrode on a downward-facing surface of a module substrate and placed on a solder paste bump of an opposing substrate.

11. The lead-free solder ball according to claim 1 , wherein the solder ball is bonded to an electrode of a module substrate and fused with a solder bump of an opposing substrate.

12. A module substrate, comprising:
an electrode; and
a lead-free solder ball according to claim 1 bonded to the electrode.

13. The module substrate of claim 12 , wherein the electrode is on a downward-facing surface of the module substrate.

Assignees

• Ohnishi Tsukasa
• Yamanaka Yoshie
• Tachibana Ken
• Senju Metal Industry Co

Inventors

• Ohnishi Tsukasa
• Yamanaka Yoshie
• Tachibana Ken

Classifications

• H10W72/952

  comprising metals or metalloids, e.g. PbSn, Ag or Cu · CPC title

• H10W72/29

  Bond pads specially adapted therefor · CPC title

• H10W72/252

  comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu · CPC title

• H10W72/221

  Structures or relative sizes · CPC title

• H10W72/01225

  in solid form, e.g. by using a powder or by stud bumping · CPC title