Research Focus Biocompatible Packaging

Smart, hybrid systems of micromechanical and microelectronic components have been shrinking in size for many years. Consequently, new fields of applications are also explored within medical technologies. Micromechanical accelerometers and inclination sensors as well as miniaturized electronic devices, which are currently being developed will become significant components of the next generation of medical implants. These systems provide the sophistication for monitoring the human organism in a new level, either in diversity and precision.

Along with this trend, the research work of Fraunhofer ENAS addresses the issues associated with biocompatible housing for medical devices and the integration of miniaturized systems while keeping their tiny dimensions. The focus is set on the selection, fabrication and characterization of suitable housing materials, either as homogeneous material or heterogeneous layer combination for an improved performance. The new deposition technologies are developed with respect to the properties of the device. This involves the designated field of application, taking into account maximum thresholds for applicable process temperatures as well as electromagnetic compatibility. The subsequent surface modification of the encapsulated device in a nanometre scale guarantees the adaption to different biological environments and allows for the desired immune response.

Due to its long experience on thin film deposition of metals, isolators and polymers, Fraunhofer ENAS is confident to manage today’s and tomorrow’s challenges in biological packaging and integration.

Means of Biocompatible packaging

• Reliable suppression of pathological interaction between organic and artificial system
• Adaption of the technical system to the human body environment
• Utilization of thin films to keep minimal package dimensions
• Integration of sensor, housing, biological adaption and communication

Following the miniaturization trend new thin film encapsulation materials are required for medical implants to ensure the protection of the device against the body environment, and to protect the body against the influence of the implant or parts of it.

Parylene as promising encapsulation layer

Parylene is a polymer, which combines a number of excellent properties and offers a wide potential for applications. The most important properties are ISO-10993 certified biocompatibility and biostability, chemical inertness against all common acids, bases and solvents, electrical isolation, hydrophobicity, transparency, and a low permeability for gases and water. Hence possible applications of Parylene are the encapsulation of medical implants, MEMS and organic electronic devices as well as the usage of Parylene as corrosion protection. Parylene coatings are produced by a CVD process within three steps: sublimation of dimer, pyrolysis and polymerization. In particular the deposition from the gas phase at ambient temperature ensures highly conformal coatings without any internal stresses.  At Fraunhofer ENAS competences for the deposition of different Parylene types are established ensuring a high quality level for its application in medical implants, MEMS and organic electronics.