Material Characterization of Test Contact Pin

Abstract

Test Contact Pin is used for testing the functionality and quality of the micro-devices at extreme temperatures before shipping to customers. The contact pin transfers current & signal to the device tested through dynamic contacting where the material resistance of the pin and the contact resistance between the pin and the device plays a significant role in influencing the effectiveness of the test process. Available material specifications for these pins in the market are for ambient temperature only. The test contact pin was characterized across temperatures onto matte Sn leadframe for its contact resistance and force with respect to number of touchdowns. Contact resistance and pin force are the key variables used to understand the mechanism of the process which is also used for determining the lifespan of the contact pin. An automated and sophisticated contact tester tool (CTT) was used to characterize the test contact pin on the mattes Tin leadframe across temperatures (-43°C, 25°C and 150°C) and at fixed pin deflection. Based on the results, it was observed that the contact resistance was higher at higher temperatures. Further data analysis revealed that this phenomenon was due to influence of various factors such as temperature, leadframe material type and the material migration of Sn from leadframe to the test contact pin tip.