Development of high speed cold ball pull as a quick turn monitor for solder joint reliability

This paper investigates the cold ball pull methodology as a quick turn monitor for characterizing the solder joint reliability of electronic packages. Since cold ball pull is a relatively new metrology, there is still no standard to regulate this testing method. In this paper, the dependence of cold ball pull test result on pulling speed is investigated. It is found that the strength of solder joints is sensitive to strain rate. For lead-free solders, high pulling speed should be employed to better expose the failures at brittle IMC interfaces. Then the high speed cold ball pull is compared with JEDEC standard board level drop test at 1500 g/0.5 ms to evaluate its accuracy. It is found that the high speed cold ball pull test can qualitatively match the JEDEC standard board level drop test. It can be employed as an effective quick turn monitor for evaluating solder joint reliability performance in electronic package development and high volume manufacturing.