Thermal fatigue test of electronic packages under temperature cycles

摘要

Equipment has been developed with which almost rectangle temperature cycles can be carriednout. The drop-down of electric voltage for each chip in an electronic package is recorded for thenthermal cycles. From the SEM observation of the specimens cut from the chips endured differentntemperature cycles, it is found that there is a strong interrelation between the fatigue damage andnthe drop-down value of electric voltage. It is also noticed that when the fatigue crack initiates fromnthe interface edges, the drop-down value will increase dramatically. An experimental criterion fornthe evaluation of chip’s fatigue life based on the drop-down of electric voltage is proposed. Thenfatigue life of different chips is obtained under different temperature cycles from the criterion.