Problem: Relatively simple microelectromechanical systems are already used in air bags and other devices, but MEMS of greater complexity hold promise in applications ranging from medical implants to advanced navigation devices. Such machines might include components like tiny sensors, motors, and power sources. The methods for manufacturing these diverse parts, however, are largely incompatible, which makes assembling complex MEMS on a large scale and at a reasonable cost impossible.
Solution: Babak Parviz, an assistant professor of electrical engineering, has developed a method of coaxing individual components to assemble themselves into MEMS devices. Recently, he used it to build a working single-crystal silicon circuit on a flexible plastic substrate; the two materials are difficult to combine using conventional manufacturing methods.
Parviz began by manufacturing micrometer-size silicon parts in bulk. He also designed a plastic substrate with binding sites whose shapes complemented those of the silicon components. Parviz immersed the substrate in a fluid containing the silicon parts, which quickly attached to their binding sites. Metal interconnects embedded in the plastic completed the circuitry.
Such silicon-on-plastic devices could form the basis for flexible displays, biosensors, and low-cost solar panels. Parviz says that self-assembly offers the ability to efficiently and cheaply manufacture multifunctional devices of all sizes from nanoscale components.
Credit: Babak Parviz
Left: To create self-assembling devices, Babak Parviz began by manufacturing micrometer-size silicon components in bulk, yielding a loose collection of parts that resembled a fine powder. Right: A finished silicon-on-plastic device made via self-assembly. Parviz designed a plastic substrate with binding sites whose shapes complemented those of the silicon components. When the plastic was immersed in a fluid containing the silicon parts, the components found their binding sites and locked into place.