Flexible silicon interconnects for microelectromechanical systems

Flexible, multilead silicon-substrate cables have been developed for connection to a variety of sensors and microelectromechanical systems. These cables are fully shielded, have been fabricated with multiple strands, and are very flexible due to the thin (2.5- mu m) silicon substrate that supports the leads. Five-lead cables with a total thickness of 5 mu m have been fabricated with lengths ranging from 2.5 to 5 cm. These cables are very flexible and yet very strong. Soak tests in buffered saline under electrical and mechanical stress show leakage currents in the sub-picoamp range after over 175 days under +or-5-V bias. Cables integrated into multichannel silicon neural recording probes have been implanted in guinea pigs and remain functional after over four months in-vivo, maintaining impedance levels in the 3-9-M Omega range. The authors present the structure and process for these shielded cables and review the electrical and mechanical characteristics of the cables, including the results of biased soak tests in saline.<>