Investigation of Electromigration on Printed Circuit Boards Soldered with Lead-Free Solder

摘要

The electromigration on printed circuit test boards after soldering process was under investigation. FR-4 laminate, that is the most popular laminate for printed circuit boards fabrication, with 35mm thick copper layer was used in the test. Six various solders were applied in this work, which differed with silver content from each other. Some solder contained lead and copper. For electromigration assessment two tests were performed: Surface Insulation Resistance Test and Water-Drop Test. Silver presence in the solder do not decreased insulation resistance of test printed circuit boards. This implies, that small silver content in a solder does not increase electromigration of solder material. The "Water drop" test showed, that silver addition decreases electrochemical migration in continuous water layer on printed circuit board surface.