IP Library › Granted Patent US 6,884,389
Granted Patent B2
US 6,884,389 · App. 10/461,500 · Granted Apr 26, 2005

Lead-free solder alloy and lead-free solder paste using the same

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Quick Facts
Patent No.
US 6,884,389
App. No.
10/461,500
Granted
Apr 26, 2005
Kind
B2
Abstract

Disclosed is a lead-free solder alloy containing 43 to 47% by weight of bismuth, 0.5 to 2.5% by weight of silver, 0.25 to 0.75% by weight of copper, 0.25 to 0.75% by weight of indium, 0.02 to 0.09% by weight of nickel and the balance of tin.

Claims (6)

1. A lead-free solder alloy containing 43 to 47% by weight of bismuth, 0.5 to 2.5% by weight of silver, 0.25 to 0.75% by weight of copper, 0.25 to 0.75% by weight of indium, 0.02 to 0.09% by weight of nickel and the balance of tin.

2. A lead-free solder alloy according to claim 1 , wherein the bismuth content falls within a range of between 44.5% by weight and 45.5% by weight, the silver content falls within a range of between 0.9% by weight and 2.2% by weight, the copper content falls within a range of between 0.4% by weight and 0.6% by weight, the indium content falls within a range of between 0.4% by weight and 0.6% by weight, and the nickel content falls within a range of between 0.05% by weight and 0.09% by weight.

3. A lead-free solder alloy according to claim 1 , further containing antimony in an amount not larger than 0.5% by weight and germanium in an amount not larger than 0.5% by weight.

4. A lead-free solder paste comprising a lead-free solder alloy containing 43 to 47% by weight of bismuth, 0.5 to 2.5% by weight of silver, 0.25 to 0.75% by weight of copper, 0.25 to 0.75% by weight of indium, 0.02 to 0.09% by weight of nickel and the balance of tin, and a flux.

5. A lead-free solder paste according to claim 4 , wherein the bismuth content of the lead-free solder alloy falls within a range of between 44.5% by weight and 45.5% by weight, the silver content of the lead-free solder alloy falls within a range of between 0.9% by weight and 2.2% by weight, the copper content of the lead-free solder alloy falls within a range of between 0.4% by weight and 0.6% by weight, the indium content of the lead-free solder alloy falls within a range of between 0.4% by weight and 0.6% by weight, and the nickel content of the lead-free solder alloy falls within a range of between 0.05% by weight and 0.09% by weight.

6. A lead-free solder paste according to claim 5 , further containing antimony in an amount not larger than 0.5% by weight and germanium in an amount not larger than 0.5% by weight.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jun 16, 2003
From: TAKAHASHI, KUNIAKI
To: KABUSHIKI KAISHA TOSHIBA
Reel/Frame 014183/0405 →