Demonstration of Hermetic Sealing on Ultra-Thin, Wafer-Integrated Aluminum-Polymer Capacitors for High-Voltage and High-Temperature Applications

Aluminum capacitors provide a superior combination of high volumetric density owing to their high-surface area structure and high voltage-stability owing to their paraelectric, natural oxide dielectric. However, these capacitors are currently not compatible with wafer-level packaging or high-temperature environments. In this research, a panel-scale fabrication and integration process is developed for aluminum thin-film capacitors with 2.2 µF/cm2 for 30-48 V applications. The performance of parylene film as a passivation film to extend the operating temperature of conducting-polymer capacitors such as the aluminum-polymer capacitors in this paper is also evaluated. A 700 nm thick passivation film is shown to provide the best combination of hermeticity and thermomechanical stability at high-temperature and high-humidity conditions.