Inkjet printers start cranking out microchips

Spray-on electronics can be mass manufactured, and a new factory in Austria is doing just that.
Written by Michael Kanellos, Contributor
Nanoident Technologies is literally squirting out semiconductors.

The company has officially opened a factory in Linz, Austria, that produces organic semiconductors, which are chips made by spraying intricate patterns of specialized ink onto layers of foil and polymer.

The factory is capable of producing 40,000 square meters of semiconductors a year, says Wasiq Bokhari, CEO of Bioident, a related company that will market Nanoident chips to the health market. The initial customers will be sister companies of Nanoident, but the company has also formed alliances with water testing companies and other industrial concerns.

A traditional factory that can produce 40,000 square meters of silicon computer chips would cost about $1.3 billion and require about 5,000 employees, he said in an interview. The Nanoident factory costs about $10 million and can be run by about 50 people.

Organic semiconductors, however, won't function as memory chips in computers or as processors. They are far slower and degrade over time. Instead, organic semiconductors will be targeted at one-time-only applications such as water purity testers: insert a water drop and the chip will analyze the chemicals floating inside of the drop. The company has also devised lab-on-a-chip chips that can extract data about a person's health through a blood sample.

Organic materials have already crept into some fields. Cell phone manufacturers already sell phones with screens made from organic light emitting diodes, or OLEDs, but few other commercial applications exist. Most of the time, organic chips appear as part of scientific papers. At University of California at Berkeley, for instance, researchers have printed an organic semiconductor that can tell its user if a bottle of wine has gone bad.

Traditional silicon chips are too expensive for these types of applications, which now are conducted on lab equipment, the company says.

The company currently has yields--a measure of the number of good chips that come out of a manufacturing run--of about 70 percent and will get to 80 percent, Bokhari said.

Building the organic beast
One of the key differences between regular and organic semiconductors is how transistors get laid down. In standard chips, lithography machines sketch a circuit pattern. Trenches are then dug into silicon and filled with metal through a complex series of chemical spraying and etchings.

With organic semiconductors, 128 inkjet nozzles spray a pattern onto foil or polymer. Researchers, though, have to account for interactions between the ink and the different layers, and the performance character of the ink.

Printed semiconductors have far larger features than silicon chips. Nanoident's first chips will have features measuring 10 to 100 microns wide. That's more than 100 times larger than the features inserted into silicon chips. Current silicon chips sport 65-nanometer features (a nanometer is one thousandth of a micron).

"We can go below 10 microns, but what are the applications that would require that?" Bokhari said. "We'd need a compelling reason for high-speed devices."

Organic semiconductors, however, can come in a variety of sizes. Nanoident has built some that measure 160 centimeters a side, or more than 1.5 meters wide. These large devices are used as sensors.

"You can't do that with silicon," he said.

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