Here is the abstract you requested from the IMAPS_2013 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Voiding at Lead-Free Low Melting and Medium Melting Mixed Alloy BGA Assembly|
|Keywords: lead-free, alloy, voiding|
|Driven by low cost consideration, low temperature soldering for PCB assembly has the potential of reducing the cost of materials for components and boards, in addition to the energy for reflow soldering. Among all options, 57Bi42Sn1Ag is one of the most attractive choices due to its low melting temperature and promising mechanical property. Since BGAs mainly employ SAC alloy for solder bump, assembly of BGA with 57Bi42Sn1Ag solder paste inevitably faces the challenge of mixed solder alloys, particularly on the voiding performance. In this study, BGA with SAC105, SAC305, or 57Bi42Sn1Ag balls are assembled with either SAC305 or 57Bi42Sn1Ag solder paste, and the joint microstructure and voiding performance are evaluated against reflow profile. The joint is also analyzed with DSC in order to identify the correlation between melting behavior and voiding.|
|Ning-Cheng Lee, VP Technology