发明申请
US20050100474A1 Anti-tombstoning lead free alloys for surface mount reflow soldering
审中-公开
反墓碑无铅合金,用于表面贴装回流焊接
- 专利标题: Anti-tombstoning lead free alloys for surface mount reflow soldering
- 专利标题(中): 反墓碑无铅合金,用于表面贴装回流焊接
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申请号: US10935118申请日: 2004-09-08
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公开(公告)号: US20050100474A1公开(公告)日: 2005-05-12
- 发明人: Benlih Huang , Ning-Cheng Lee
- 申请人: Benlih Huang , Ning-Cheng Lee
- 主分类号: B23K35/26
- IPC分类号: B23K35/26 ; C22C13/00 ; H01L20060101 ; H05K3/34
摘要:
A lead-free solder alloy composition comprising tin, silver and copper, and a process for reflow soldering for minimizing tombstoning frequency are disclosed. In one particular exemplary embodiment, the lead-free Sn—Ag—Cu solder alloys for minimizing the tombstoning effect of the present disclosure display high mass fraction during melting and prolonged melting as shown by a widened DSC peaks, that allows for a balanced surface tension on both ends of the chip component to develop. In accordance with further aspects of this exemplary embodiment, the alloys display a mass fraction of solid during melting greater than 20% and a DSC peak width greater than 8° C. using a 5° C./min scan rate. In accordance with further aspects of this exemplary embodiment, the alloy comprises on a weight basis Ag 1-4.5%, Cu 0.3-1% balanced with Sn.
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