摘要 |
Problem To improve the electromigration (EM) resistance of a solder joint. Solution The present invention provides a unique structure for an interfacial alloy layer which is able to improve the electromigration (EM) resistance of a solder joint, and a unique method of forming this structure. More specifically, in this unique structure, a controlled interfacial alloy layer is provided on both sides of a solder joint. In order to form this structure, aging (maintenance of high-temperature conditions) is performed until an interfacial alloy layer of Cu3Sn has a thickness of at least 1.5 mum. |