Whisker-Like Formations in Sn-3.0Ag-Pb Alloys

Abstract

In this study, different types of whisker-like formations of Sn-3.0Ag based alloy were presented. In the experimental process the amount of Pb element was changed between 1000 and 2000 ppm, and the furnace atmosphere and cooling rate were also modified. The novelty of this work was that whisker-like formations in macro scale size were experienced after an exothermic reaction. The whiskers of larger sizes than general provided opportunities to investigate the microstructure and the concentration nearby the whiskers. In addition, the whisker-like formations from Sn-Ag based bulk material did not only consist of pure tin but tin and silver phases. The whisker-like growth appeared in several forms including hillock, spire and nodule shaped formations in accordance with parameters. It was observed that the compound phases were clustered in many cases mainly at hillocks.

The Use of IR Soldering Stations in the Process of Disassembling in BGA Packaging

“…the occurrence of whiskers (threaded hair shapes up to 5ʅm in diameter and several millimeters long), short circuits caused by connecting several leads of the element with the solder metal as a result of the soldering process, and also due to human fault: incorrect selection of the soldering profile, which affects the quality of the connection, or a rapid increase in temperature, which, combined with moisture, leads to the formation of bubbles on the packaging (i.e. steam and other gases trapped in the packaging walls are the cause of delamination and cracking) [3][4][5]14].…”