Invention Grant
- Patent Title: Low temperature melting and mid temperature melting lead-free solder paste with mixed solder alloy powders
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Application No.: US16518180Application Date: 2019-07-22
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Publication No.: US11267080B2Publication Date: 2022-03-08
- Inventor: Hongwen Zhang , Fen Chen , Francis Mutuku , Jie Geng , Ning-Cheng Lee
- Applicant: Indium Corporation
- Applicant Address: US NY Utica
- Assignee: Indium Corporation
- Current Assignee: Indium Corporation
- Current Assignee Address: US NY Utica
- Agency: Sheppard, Mullin, Richter & Hampton LLP
- Priority: CN201910383054.3 20190509
- Main IPC: B23K35/00
- IPC: B23K35/00 ; B23K1/00 ; B23K35/26 ; C22C13/02 ; B23K35/02 ; B23K1/008

Abstract:
Implementations of the disclosure are directed to a lead-free mixed solder powder paste suitable for low temperature to middle temperature soldering applications. The lead-free solder paste may consist of: an amount of a first solder alloy powder between 44 wt % and 83 wt %, the first solder alloy powder comprising Sn; an amount of a second solder alloy powder between 5 wt % to 44 wt %, the second alloy powder comprising Sn, where the first solder alloy powder has a liquidus temperature lower than a solidus temperature of the second solder alloy powder; and a remainder of flux. The solder paste may be used for reflow at a peak temperature below the solidus temperature of the higher solidus temperature solder powder but above the melting temperature of the lower solidus temperature one.
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