Development of innovative cold pin pull test method for solder pad crater evaluation

Hot pin pull test is one of the testing methods frequently used in the pad crater evaluation. Although it carries several merits comparing with the other testing methods, it still has certain drawbacks such as time consuming and the potential thermal impact on the PCB copper pad during the pin attachment process. In this paper, an innovative cold pin pull testing method is introduced. Using a set of fixtures designed and manufactured in advance, an array of pins can be attached to the pre-deposited solder balls at one time. Therefore, instead of attaching the pin one by one, the test panel with pin arrays can be prepared after only two times of reflow. Compared with conventional cold ball pull tests, this newly developed method can not only equally exhibit the pad crater characteristics of the PCB, but also reduce the testing variations, which could be proven by experimental data generated in the present study.