Effects of silver content on drop property of lead-free solder joint

In order to improve the drop property of SnAgCu lead-free solder joint, the effect of silver content on drop property of solder joint was investigated and the experimental results were analyzed by statistics method. Results show that with the decreasing of silver content in SnAgCu solder, under the significance testing at 99% probability, the drop property of solder joint can be improved significantly. The solder joint with a preset gap has a shorter drop lifetime. During drop test, failures occur at the interface layer between copper base metal and solder material for all solder joints. The brittle fracture characteristic exists in the appearance of failure position. It is found that the interface layer is getting thinner continuously with the decreasing of silver content, which might be the main cause to improve the drop property of solder joint.