For an integrated free-space optical interconnection system we suggest the use of microprisms to achieve large coupling angles at low loss. Prisms were fabricated in photoresist and quartz glass by analog lithography. High-energy-beam-sensitive glass was used as the gray-tone mask. Optical testing of the prisms shows acceptable surface quality and high efficiency (95%).

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A method for aligning a photolithographic mask at the top of a transparent wafer that has a pattern on its bottom side is presented. The method is based on optical self-imaging of special alignment marks and provides submicrometer accuracy. The method is simple and robust and can conveniently be implemented on laboratory mask aligners for contact or proximity printing.

The design of a multichip module with planar optical interconnects is presented. Electrical (local) interconnects for intra-chip communication and optical interconnects for chip-to-chip communication are implemented onto the same substrate of a planar-integrated free-space optical system. We suggest to integrate the optical emitter/detectors (VCSEL diodes) into solder balls; onto these solder balls IC carrying silicon chips can bē ip-chip bonded like on a common ball grid array. With respect to the thermal load thermally conductive vias are incorporated into the package, too. We show that typical packaging errors can be tolerated by the optical system, which is designed for space variant interconnects and enables thin ®lm replication techniques of temperature sensitive materials.

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