Tiny Chiplets: A New Level of Micro Manufacturing

If perfected, it could lead to desktop manufacturing plants that “print” the circuitry for a wide array of electronic devices

Under a microscope, four slivers of silicon — electronic circuits called chiplets — perform an elaborate, jerky dance as if controlled by a hidden puppet master. Then on command, they all settle with pinpoint accuracy, precisely touching a pattern of circuit wires, each at just the right point of contact.

The technology, on display at Xerox’s Palo Alto Research Center, or PARC, is part of a new system for making electronics, one that takes advantage of a Xerox invention from the 1970s: the laser printer.

If perfected, it could lead to desktop manufacturing plants that “print” the circuitry for a wide array of electronic devices — flexible smartphones that won’t break when you sit on them; a supple, pressure-sensitive skin for a new breed of robot hands; smart-sensing medical bandages that could capture health data and then be thrown away.

Today’s chips are made on large wafers that hold hundreds of fingernail-sized dies, each with the same electronic circuit. The wafers are cut into individual dies and packaged separately, only to be reassembled on printed circuit boards, which may each hold dozens or hundreds of chips.

The PARC researchers have a very different model in mind. With financing from the National Science Foundation and from Darpa, the Pentagon’s Defense Advanced Research Projects Agency, they have designed a laser-printer-like machine that will precisely place tens or even hundreds of thousands of chiplets, each no larger than a grain of sand, on a surface in exactly the right location and in the right orientation.

The chiplets can be both microprocessors and computer memory as well as the other circuits needed to create complete computers. They can also be analog devices known as microelectromechanical systems, or MEMS, that perform tasks like sensing heat, pressure or motion.

The new manufacturing system the PARC researchers envision could be used to build custom computers one at a time, or as part of a 3-D printing system that makes smart objects with computing woven right into them.

The technology is still in the future. The researchers are years from simultaneously placing tens or hundreds of thousands of circuits accurately in a fraction of a second. And they acknowledge that this would be only the first step in designing a commercially viable system.

Still, if the PARC researchers are successful, they will have thrown out 50 years of Silicon Valley conventional wisdom.

A related but simpler technology was pioneered by Alien Technology, a maker of RFID tags in Silicon Valley. Called Fluidic Self Assembly, it is based on suspending small integrated circuits called “nanoblocks” in a fluid and then flowing them over a surface where they drop into tiny holes of corresponding shapes.

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Both approaches reverse a five-decade long tradition of making computers faster and more powerful by doubling every two years the number of transistors squeezed onto fingernail-sized computer chips.

The emerging printing technology poses a heretical idea: Rather than squeezing more transistors into the same small space, why not smear the transistors across a much larger surface?

Moreover, the research could have tremendous economic consequences — feeding the emergence of a new digital era in manufacturing, much as laser printing transformed publishing three decades ago.

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