HOT-300 - a multidisciplinary technology approach targeting microelectronic systems at 300 °C operating temperature

Several applications in the fields of industrial sensors and power electronics are creating a demand for high operating temperature of 300 °C or even higher. Due to the increased temperature range new potential defect risks and material interactions have to be considered. As a consequence, innovation in semiconductor, devices and packaging technologies has to be accompanied by dedicated research of the reliability properties. Therefore various investigations on realizing high temperature capable electronic systems have shown that a multidisciplinary approach is necessary to achieve highly reliable solutions. In the course of the multi-institute Fraunhofer internal research program HOT-300 several aspects of microelectronic systems running up to 300 °C have been investigated like SOI-CMOS technology and circuits, silicon capacitor devices, a capacitive micromachined ultrasonic transducer (CMUT), ceramic substrates and different packaging and assembly techniques. A ceramic molded package has been developed. Die attach on different leadframe alloys were investigated using silver sintering and transient liquid phase bonding (TLPB). Copper and gold wire bonding was studied and used to connect the chips with the package terminals. Investigations in flip chip technology were performed using Au/Sn and Cu/Sn solder bumps for transient liquid phase bonding. High operating temperatures result in new temperature driven mechanisms of degradation and material interactions. It is quite possible that the thermomechanical reliability is a limiting factor for the technology to be developed. Therefore investigations on material diagnostics, reliability testing and modeling have been included in the project, complementing the technology developments.