Processing and characterization of benzocyclobutene optical waveguides

Digital circuits are continuing to see an increase in clock speeds which puts significant demands on the design and packaging of electronic subsystems. One possible solution is to take advantage of the high bandwidth of optics. This has clearly taken place for long-distance telecommunications, but has yet to happen at the board- or chip-level in electronic systems. While there are many reasons for this, one serious issue concerns the materials that are required to achieve optical signal transmission in the electronic system. First and foremost, the material must exhibit low optical loss. The material must also be compatible with the standard processing techniques of printed wiring boards, multichip modules, or integrated circuits. In addition, the materials must be easily processed into the desired optical structures. In this paper, we present our work on using benzocyclobutene as an optical waveguide material. Benzocyclobutene is an advanced organic polymer that is ideally suited as a dielectric layer in high-speed digital circuits. We show that as a waveguide material, single-mode (1300 nm) optical waveguides can be fabricated with losses of 0.81 dB/cm. Detailed processing conditions are discussed