Correlation analysis of wettability, intermetallic compound formation and PCB contamination
Abstract
Purpose
The purpose of this paper is to verify how solder joint properties correlate with soldering profile set-up. These characteristics act against each other. All observed properties may significantly affect the quality and reliability of solder joints. The purpose is also to design recommendations for manufacturers of electronic assemblies.
Design/methodology/approach
The samples for experiment were reflowed by using a laboratory reflow oven. A LEXT laser confocal microscope was used for wetting angle and intermetallic compound (IMC) thickness measurement. The ionic contamination was measured by using a contaminometer.
Findings
The appropriate choice of soldering profile is very important for the reliability of electronic assemblies. The higher temperatures or longer preheating and soldering times improve the wetting angle. Likewise, there is also the activation of all the fluxes. The result is low contamination with printed circuit boards (PCBs). On the other hand, we must not forget that higher temperatures and longer soldering time also affect the thickness of the IMC. The outer limits recommended by the manufacturer were selected for the soldering profile set-up. Even within these limits, it is possible to achieve an improvement in the wetting angle, an improvement in levels of PCB contamination and an increase in the thickness of the IMC. This paper presents the results achieved for solders Sn42Bi57.6Ag0.4, Sn96.5Ag3Cu0.5 and Sn97Ag3.
Originality/value
The gained knowledge on the correlation between IMC thickness, solderability of PCB and PCB contamination caused by different soldering profile set-ups can help to prevent reliability problems because each of the named effects has a significant influence on reliability.
Keywords
Acknowledgements
This research has been supported by the European Regional Development Fund and the Ministry of Education, Youth and Sports of the Czech Republic under the Regional Innovation Centre for Electrical Engineering (RICE), project No. CZ.1.05/2.1.00/03.0094.
Citation
Steiner, F., Rendl, K. and Wirth, V. (2015), "Correlation analysis of wettability, intermetallic compound formation and PCB contamination", Circuit World, Vol. 41 No. 2, pp. 70-75. https://doi.org/10.1108/CW-10-2014-0047
Publisher
:Emerald Group Publishing Limited
Copyright © 2015, Emerald Group Publishing Limited