TIN-ZINC LEAD-FREE SOLDER, ITS MIXTURE, AND SOLDER-JOINED PART

Title:

TIN-ZINC LEAD-FREE SOLDER, ITS MIXTURE, AND SOLDER-JOINED PART

Document Type and Number:

WIPO Patent Application WO/2004/018145

Kind Code:

A1

Abstract:

A tin-zinc lead-free solder contains tin as a main component and essentially at least 6-10 weight% of zinc. A protective film of magnesium oxide is formed on the surface of the solder. The solder also contains 0.0015 to 0.1 weight% of magnesium, at which percentage the oxide protective film can be broken when the solder is melted. While a paste of this solder is stored, the magnesium oxide protective film formed on the solder particles protects the inside of the solder particles and suppresses the reaction between the zinc and an activator to prolong the shelf life. The oxide protective film is subject to breakage when the solder is heated and melted to maintain the favorable wettability.

Inventors:

YOSHIKAWA MASAAKI (JP)
AOYAMA HARUO (JP)
TANAKA HIROTAKA (JP)

Application Number:

PCT/JP2002/011990

Publication Date:

March 04, 2004

Filing Date:

November 18, 2002

Export Citation:

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Assignee:

NIPPON METAL IND (JP)
YOSHIKAWA MASAAKI (JP)
AOYAMA HARUO (JP)
TANAKA HIROTAKA (JP)

International Classes:

B23K35/02; B23K35/14; B23K35/26; C22C13/00; H05K3/34; (IPC1-7): B23K35/14; B23K35/26

Foreign References:

JP2000015478A	2000-01-18
JP2000210788A	2000-08-02
JP2002248596A	2002-09-03
JP2002283093A	2002-10-02

Other References: