Fraunhofer Institute for Electronic Nano Systems
Within the Fraunhofer Lighthouse Project »Theranostic Implants«, technologies for future implants were developed. Theranostic, an artificial word, means the combining diagnostic and therapeutic features in a device, which measures and acts autonomously.
The overall system consists of a pressure sensor, an ASIC for data and energy management, an accelerometer for measuring the position of the patient and an interposer as a base, whereby the ASIC and the pressure sensor were developed by Fraunhofer IMS.
As a the base of the system, an LTCC interposer with 75 μm line/space and 13 layers in a stack, provided by NIKKO (Japan), contains a coil for inductive energy supply and data transmission. The ASIC and the MEMS accelerometer are mounted onto the interposer either by flip-chip bonding with gold stud bumps or by die attach and wire bonding. The buildup was investigated in regard to bond quality and voids with microcomputer tomography (Micro-CT) equipment and scanning acoustic microscopy (SAM).
Last but not least, an Al2O3/Parylene thin film multilayer approach has been used for biocompatible and hermetic encapsulation. Finally, the highly miniaturized system (length: 15 mm, diameter: 3 mm) will be tested for functional operation after silicone encapsulation together with Fraunhofer IMS.