Online proceedings - EDA Publishing Association

Conclusions
Microstructured borosilicate thin-films are used to form
bond frames and cavities on optical wafers. Direct anodic
bonding of these structures has been demonstrated for glassto-silicon
and silicon-to-silicon wafers. The use of the
Lithoglas structures as bond layers opens up the opportunity
to anodic bond two silicon device wafers using only one
anodic bond step. Furthermore the bond layer can be easily
structured by lift-off and can hermetically seal underlying
electrical leads forming a hermetic feed-through. Due to the
outstanding dielectric properties of the borosilicate thin-films
advanced bond parameters can be used enabling a fast anodic
bond process and with this lowering the costs of hermetic
wafer-level integration of silicon devices.
A novel “Cavity-by-Grind” process was introduced, which
allows the cost-effective manufacturing of optical cap-wafers
with deeper cavities (some ten to some hundred micrometres)
with high yields and high optical performance.
The use of capped device for conventional COBpackaging
was discussed.
Acknowledgments
MSG Lithoglas AG wishes to thank Prof. Klaus-Dieter
Lang, Oswin Ehrmann and their team of Fraunhofer Institute
for Reliability and Microintegration in Berlin for their
ongoing support.
Parts of the work was part-funded by the European
Regional Development Fund (ERDF) and the government of
Berlin, Germany as well as by the Federal Ministry of
Education and Research, Germany.
11-13 May 2011, Aix-en-Provence, France
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