Patent ID: 8207469
Filing Date: 2012-06-26
Classification: B23K,H05K,Y02P

Abstract:
1. A method for inhibiting electromigration-induced phase segregation, suitable for solder joints used in a chip package, the method comprising: providing a chip package including a wiring board, a chip and a number of solder joints, wherein the chip is disposed on the wiring board, and the solder joints are disposed between the chip and the wiring board to electrically connect the chip to the wiring board; and alternately applying a first current and a second current to a side of the solder joints, wherein the first current is continuously applied for a first period and then the second current is continuously applied for a second period that is equal to the first period, current directions of the first current and the second current are opposite, and the current density of the first current is 10 3 -10 5 A/cm 2 , and the current density of the second current is 10 3 -10 5 A/cm 2 , wherein an alternate frequency of the first current and the second current is 0.05 min −1 (1 cycle per 20 minutes).