Rhonda Franklin Drayton University of Minnesota

Advanced Packaging Concepts in Silicon Substrates

High-speed packaging is critical to the next generation of optical and optoelectronic communication technologies. The research activities in the Microwave Packaging and Circuit Research Group (MPACt) focuses on developing advanced high-speed packaging concepts for microwave and optoelectronic applications. In this presentation, topics related to integration of high frequency electrical and optical design will be addressed.

One topic addresses direct integration of 40 GHz electrical interconnects into onto silicon optical micro-bench packages. This integration produces low dispersion high density interconnects, which is important for digital and analog applications. One such application is modulation of optical sources or as drivelines in modulator devices. In our approach, silicon micromachining is used to selectively reduce the substrate height and thereby offers scaling of 50 electrical interconnects to satisfy optical array requirements, such as VCSEL devices. Traditional methods use external chips with narrow interconnect (10 m) dimensions that result in non-50 lines. Such methods present undesirable reflections in high data rate designs due to impedance mismatch between the external device and optical one. This results in performance degradation in optical system performance, especially above 40 GB/s.

The second topic addresses the need to have low-loss electrical designs in CMOS grade substrates in order to extend optical platform integration to include electrical drivers and passive components. We are investigating novel silicon based materials, such as porous silicon, and developing appropriate high frequency electrical characterization methods to assess their potential in high-speed applications. Initial finding indicate substantial loss reduction to standard CMOS substrates, thus, showing promise for integration with silicon optical microbench technology and other silicon based designs requiring high frequency performance.

Bio
Rhonda Franklin Drayton received her B.S.E.E. Degree from Texas A&M University, College Station, TX in 1988, and the M.S.E.E. and Ph.D. degrees from the University of Michigan, Ann Arbor, MI in 1990 and 1995, respectively.

She joined the Department of Electrical and Computer Engineering at the University of Minnesota, Twin-Cities campus as an assistant professor in 1998 after two years on faculty in Department of Electrical and Computer Science at the University of Illinois at Chicago (UIC). Her research interests include integrated package and interconnect design for high-speed electronic and optoelectronic applications, microwave and millimeter-wave planar circuit and antenna design, advanced fabrication techniques (e.g. Si micromachining and porous silicon) and characterization of advanced high frequency materials.

Dr. Drayton has co-authored over 40 articles in refereed journals and refereed conference symposia proceedings for her work on micromachined packages for high-speed applications in addition to two book chapters on the same topic. Her accomplishments include research and teaching awards that include the National Science Foundation CAREER Award in 1998 and the prestigious Presidential Early Career Award for Scientist and Engineers (PECASE) in 1999. She is also an invited participant to the National Academy of Engineering - Frontiers in Engineering (2002) and German-American National Academy of Engineering - Frontiers in Engineering (2003).