Reliability of plastic-encapsulated electronic components in supersaturated steam environments

Medical steam sterilizers use rapid cycles of temperature, humidity, and pressure to sterilize medical instruments. These cycles represent an exceptionally harsh environment for electronics and, currently, only metal can devices with high-reliability electronic components can be used to electronically monitor and verify the completeness of sterilization. The work presented in this paper has allowed the identification of a material set that allows plastic-encapsulated electronic modules with commercial-off-the-shelf electronic components and sensors, assembled on organic circuit boards, to survive over 100 sterilization cycles. In the course of the work, the failure mechanisms of the plastic-encapsulated modules and the deterioration of encapsulant adhesion over multiple sterilization cycles have been characterized. This opens the possibility of using plastic-encapsulated embedded electronics in smart medical and biomedical devices, which need resterilization after every use.