抄録
High-temperature enclosed electrochemical migration （ECM） is one of the new defects in the board assembly that occurs at the sealed bottom electrode when the device gets heated with running for a long period of time. This defect can also occur in the dry conditions unlike ordinary ECM. We have developed a novel method that can easily reproduce this phenomenon so that the migration behavior can be observed. The formation of high-temp enclosed ECM is caused by movement of the metal ions, when the flux residue underneath the electrode is soft and has high fluidity. Therefore, it can be prevented by optimizing the elastic modulus of the flux residue at the component operating temp. This approach is effective even if the flux residue contains a large amount of
activators such as organic acids.
