Analysis of solder joint fracture under mechanical bending test
1. Abstract Recently, Electroless-Nickel and Immersion Gold (ENIG) plating has been applied for metalization of package substrate, because of the difficulties of routing for high pin count package. And we have been experienced that ENIG may cause the electrical open failure by some mechanical stress at In-Circuit Test (ICT) after package mount on printed circuit board (PCB), for example. In order to clarify the phenomena of solder joint fracture which causes open failure, we have been performing a four-point bending test and succeeded to optimize the condition of four-point bending test getting same phenomena as actual failure mode. This test procedure will be effective to simulate the reliability of solder joint. For fourpoint bending test, the daisy chained PCB and Flip-Chip BGA (FC-BGA) package which is 1848pin with 45mm body size, l.0mm ball pitch, were used.