May 18, 2011 — Conventional ICs are rigid, planar, and brittle. Current flex circuit laminate/metal/laminate structures limit performance and circuits suffer broken interconnects after repeated flexing. The holy grail of flexible electronics would combine the performance of ICs with a form factor that could be stretched, twisted, and conformed to unconventional shapes. David Icke, CEO, MC10 Inc. spoke about flexible electronics in his ConFab Emerging Technologies talk, "Electronics Anywhere: Conformal, Stretchable Electronics Technology & Applications."

Icke discussed flexible silicon nanoribbons that use familar wafer fab processes (think etch, encapsulation) in new IC concepts. "Acordian physics" allow these ribbons to bend and twist without compromising reliability. Conformal polymeric substrates are also in use to reduce stress on the electronics during stretching or twisting, or combinations of movement. The wavy design of Si nanoribbons absorbs strain during excursions (see figure), cushioning the active micro-CMOS "chip" elements. A neutral mechanical plane also limits strain.

The process that Icke described is compatible with conventional foundry equipment and processes, and promises low cost with high yields. >GHz performance is acheivable. The process could ramp for electronics, as well as photovoltaics, LEDs, thin-film batteries, thermoelectric devices, piezoelectrics, sensors, etc.

The electronics can be patterned on unusual substrates (leather, for instance) and shapes (how about a golf ball?). Bending mechanics and interconnect designs are modeled and optimized to accommodate desired configurations and geometries. New flexible electronics can interface with users in revolutionary ways — integrating with the eye or skin, or implanted into the body. Accepted form factors and IC lifetimes, power consumption are not restraints.

Icke shared some ideas for the technology’s application: human-integrated electronics, wearable energy sources, advanced curved imagers, and many other options.

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