鉛フリーはんだにおけるイオンマイグレーションの水晶振動子マイクロバランス法による in situ 評価

抄録

Ionic migration often observed in the presence of moisture causes short circuits between electrodes on printed circuit boards and reduces reliability. Many reports suggest that anode dissolution rate and cathode deposition rate affect ionic migration time when short circuits occur. Therefore, to analyze these ionic migration processes, in situ measurement of anode and cathode surface reactions is indispensable. We have already reported that in situ measurement of silver, copper, or solder migration in de-ionited distilled water is possible by applying a quartz crystal microbalance (QCM). We report here the migration processes of lead-free solder in air and nitrogen atmospheres by means of QCM. We found that the main deposited component of lead-free solder is tin, that of older lead-based solders is lead, and that lead-free solder is less prone to migration than older lead-based solders.