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.
|Immersion Tin for QFN-Packages to create a 3-D solder joint for reliability enhancement|
|Keywords: QFN Packages, Immersion Tin for QFN, Solder Filet QFN|
|The QFN package is one of several package technologies that connect ICs to the surfaces of PCBs without through-holes. The standard QFN Package soldered on a PCB is shown on Picture 1: As shown, the side edges of the QFN are not covered by solder which results in the fact that the package is soldered only planar from the bottom side onto the PCB. Picture 2 shows a QFN were the side edges of the package are covered with immersion Tin. This allows the package to be soldered in 3 dimensions onto the PCB providing a stronger solder joint and a better reliability. The suggested paper describes a new process to cover the side edges of the package with immersion tin after the QFN package singulation step. The exposed lead frame edges are covered by immersion tin. No exposed copper is visible and delivers a three dimensional solder joint with better reliability and protection for the soldered package.|
|Mustafa Oezkoek, Global Product Manager Surface Finishes