Fraunhofer Institute for Silicon TechnologyWith the integration of optical functions into the world of microsystems, wafer-level packaging (WLP) of components and systems is facing new and exciting challenges. Future new applications, such as augmented and virtual reality in lightweight glasses (AR/VR glasses), require the development of small optical packages, which implies a wide variety of design aspects from the optical, electrical and thermal domains.
Optical packages for encapsulating components at wafer level - technology kit opens up new perspectives
State-of-the-art manufacturing processes for processing glass
ISIT has applied the precise processes of structure transfer in silicon to other materials as well. The shaping of various glasses has proven to be particularly significant. Since glass has a similar coefficient of thermal expansion (e.g. borosilicate glasses) as silicon, it is ideally suited for anodic bonding. This produces a material compound that remains stable even under large temperature changes.
High-quality optical components at low cost
The process of high viscosity shaping of glass developed at Fraunhofer ISIT allows the fabrication of precise optical components on wafer level for different applications at low cost. For example, lenses, concave mirrors or glass domes of high optical quality have been manufactured using this process. This technology has been significantly further developed in recent years. In the meantime, ISIT offers its customers a multifaceted technology platform as a modular system, which opens up numerous new functionalities. In addition to the technological further development of the glass manufacturing processes, simulation programs are now also used at ISIT in order to be able to further optimize the shaping process. Optical measurement techniques have been set up to characterize the finished components.
But that is not all. The technology kit also makes it possible to feed electrical contacts through a glass wafer, or to precisely mount individual components such as laser diodes or lens elements on a carrier wafer by means of high-precision laser soldering, and then to encapsulate them together with a suitable glass wafer. Virtually any desired micro-optical or micro-opto-mechanical structure can be implemented, operated under vacuum or even filled with various gases.
Opportunities for SMEs
Small companies in particular are presented with opportunities. They can implement their innovative ideas without having to buy suitable machines themselves, but can draw on ISIT's equipment pool. For example, on a complex, high-precision placement system whose capabilities in component handling and joining techniques allow versatile applications. The ISIT scientists demonstrated the manifold possibilities of the technology construction kit by setting up a miniaturized RGB laser source based on silicon substrates.