Effect of humidity on storage reliability of plastic encapsulated microcircuits devices in hygrothermal environment

According to the storage reliability problems of plastic encapsulated microcircuits (PEM) devices in hygrothermal environment, effect of humidity on moisture absorption, surface estate and electrical performance of PEM was investigated through hygrothermal test. The results show that, humidity in the environment obviously affects moisture absorption process of PEM; Along with higher relative humidity at the same temperature, moisture absorption rate becomes bigger and moisture absorption content grows larger, but moisture has little effect on the time for moisture absorption content getting the biggest, moisture absorption content usually has the biggest value after 300h; Corrosion of component leads was found to be a main failure mode of PEM in hygrothermal environment, and the components have higher corrosion grade if the relative humidity is higher, and the defects, cracks and pinholes on the leads are considered to be the corrosion susceptible sites of the devices; In the tested storage time, humidity in the environment has little effect on the electrical performance of PEM.