The handling of a continuously increasing amount of data leads to a strong need for high-speed short-range connections.
Conventional Cu technology between chips on a board is limited. Optical interconnects will dominate the market, since
they can overcome the limitations. One of the issues for materials used, e.g., for waveguides embedded in printed circuit
boards (PCBs) is the compatibility with standard epoxies used for PCBs during the entire board fabrication process.
Materials applied for optical interconnects should be mechanically and optically reliable, and also allow low-cost
production. From the material production side, the process should be easy to up-scale. Therefore, anticipatory research
strategy and suitable tailoring is asked for.
The handling of light in the UV and visible range often requires the use of specially designed materials. Most polymer
materials show an increased yellowing effect upon being exposed to shorter wavelength light. The major influence on the
absorption in the UV and visible range of a UV curable material is related to the UV initiator, beside any other
chromophores formed mainly during the exposure.
Different material approaches will be presented which fulfil the requirements for highly sophisticated applications in
optics / optical packaging technology. Firstly, an epoxy-based material system for optical chip-to-chip interconnection
will be introduced. Secondly, the adaptation of a UV patternable inorganic-organic hybrid material (ORMOCER®)
originally developed for waveguide applications in the data and telecom regime, will be discussed with respect to
applications in the visible regime. Spectroscopy and UV-DSC measurements were carried out to investigate the influence
of standard photoinitiators on the optical properties for an ORMOCER® system suitable for microoptic applications. The
results show that the resulting material properties were significantly improved by exchange of the initiators compared to
the originally incorporated one.