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US 11,229,979 B2Granted
High reliability lead-free solder alloys for harsh environment electronics applications
AssigneeIndium Corporation
InventorsWeiping Liu, Ning-Cheng Lee
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Abstract
A SnAgCuSb-based Pb-free solder alloy is disclosed. The disclosed solder alloy is particularly suitable for, but not limited to, producing solder joints, in the form of solder preforms, solder balls, solder powder, or solder paste (a mixture of solder powder and flux), for harsh environment electronics. An additive selected from 0.1-2.5 wt. % of Bi and/or 0.1-4.5 wt. % of In may be included in the solder alloy.
Claims12
A solder alloy, consisting of:
- 3.8 wt. % of Ag;
- 0.9 wt. % of Cu;
- 5.5 wt. % of Sb;
- 0.5 wt. % of In;
- optionally, 0.001-0.2 wt. % of at least one of Ni and Co;
- and
- a remainder of Sn.
4 more elements
A solder paste, consisting of:
- flux;
- and
- a solder alloy powder consisting of:
- 3.8 wt. % of Ag;
- 0.9 wt. % of Cu;
- 5.5 wt. % of Sb;
- 0.5 wt. % of In;
- optionally, 0.001-0.2 wt. % of at least one of Ni and Co;
- and
- a remainder of Sn.
7 more elements
A solder joint formed by the process of:
- applying a solder alloy between a substrate and a device to form an assembly;
- and
- reflow soldering the assembly to form the solder joint;
- wherein the solder alloy consists of:
- 3.8 wt. % of Ag;
- 0.9 wt. % of Cu;
- 5.5 wt. % of Sb;
- 0.5 wt. % of In;
- optionally, 0.001-0.2 wt. % of at least one of Ni and Co;
- and
- a remainder of Sn.
8 more elements
Dependencies are inferred from the claim text.