Enhanced moisture stress test method for capacitors

This study focuses on investigating the reliability of ceramic and tantalum capacitors by enhancing the stress effect of moisture with voltage on/off-periods. Display units with ceramic and tantalum capacitors were tested at 85degC-85-percent relative humidity (85/85) with an operating voltage of 15 V for the first 1620 hours. A voltage cut-off of 70 hours was done after 1620 hours, after which the test continued. On the basis of the results, it seems that in the case of tantalum capacitors the combined stress effect of moisture and voltage can be enhanced with periodic off times. In contrast, ceramic capacitors seem to maintain their integrity despite the off-period during 85/85 testing. The ceramic capacitors outlasted the tantalum ones since the tantalum capacitors were noticed to absorb moisture during the off period. Enhancement of the stress effect was not discovered without the initial 1620 hours temperature-humidity test. Possible reasons are discussed in the paper.