Ed’s Threads 071123
Musings by Ed Korczynski on November 23, 2007

Printed silicon RF-IDs by Kovio
Humans like to tag and track things. This natural tendency has led from physical tags and labels to bar-codes and today radio-frequency identity (RF-ID) chips. There has been controversy over the possibly use of “active” RF-ID tags being used to secretly track people, but simpler “passive” RF-IDs seem inherently much more difficult to secretly track since they generally require a sensor to be in very close proximity. Plus, disposable items just aren’t great at tracking people, so we can unreservedly applaud printed silicon ICs for passive RF-IDs from privately held Kovio, Inc.

Kovio, founded by a team of scientists in the MIT Media Laboratory, has come out of R&D stealth mode with a printable silicon IC technology with first applications for extremely high-volume manufacturing of passive RF-IDs. In an exclusive interview with WaferNEWS, Vikram Pavate, Kovio’s vice president of Business Development, discussed the applications of this new printed IC technology. The only manufacturing details released so far are that minimum linewidths will be around one mil using liquid-phase inorganic “inks” for all film precursors needed to form CMOS silicon thin-film transistors (TFT), and the fact that the substrates will be flexible foils. This combines the low cost of graphics printing with the power of silicon-based semiconductors that can function at frequencies of MHz and above.

Many companies and R&D labs have been aiming at getting the electron mobility—expressed in units of cm2/(V·s)—of organics semiconductors up to the 0.5-1.0 range of amorphous-silicon TFTs. In contrast, Kovio’s all-printed silicon TFTs are claimed to exhibit electron mobility of ~80 cm2/(V·s). The team at Kovio includes technology executives from Spansion along with people from the former Matrix Semiconductor—which pioneered the use of deposited active layers in commercial chips.

“We’ve been able to start with all the conventional materials set used by the semiconductor industry, and creating a new paradigm on how you manufacture circuits. You’re working with dielectrics and metals that people are used to work with,” explained Pavate. “We’re very complementary to traditional silicon; traditional silicon will always address high-end RF-ID and reader chips.”

Based on claimed breakthroughs in nanotechnology and materials science, Kovio has developed functional electronic inks include silicon, doped silicon, metals, and insulators. Combining functional electronic inks with high-resolution graphics printing technologies, Kovio has printed high-performance silicon CMOS TFTs on flexible substrates at a fraction of the cost of conventional lithography-based silicon technology. The significantly lower cost is possible as a result of additive digital printing processes, lower capital expenditures, and faster cycle time.

Kovio’s high mobility CMOS allows for work with synchronous protocols, where the signal-to-noise ratios are better. “With these results we can print CMOS, while most organic electronics have been only PMOS,” said Pravate. “We are the first company to report a printed PMOS/NMOS device.” Kovio's technology is also attractive from an environmental and energy consumption standpoint. “We use 0.05% of the hazardous gases and 25% of the power that a traditional silicon fab would use. Plus, you can print these in a day or two, so there’s a significant cycle-time advantage we get as well,” asserted Pavate.

To accelerate the commercialization of its technology, Kovio has announced two separate joint development and supply agreements with Toppan Forms Co. Ltd., a world leader in printing businesses, printable electronics and digital information technologies, and Cubic Transportation Systems, Inc., a subsidiary of Cubic Corporation, the world's leading turnkey solution provider of automated fare collection systems for public transport.

“Our initial focus is to provide the market with low-cost RF-ID. Then we’ll add sensors and displays working with partners to create what we call item-level intelligence. One example could be a glucose-sensor on a medicine bottle that would inform specific dosing.

The market for passive RF-ID chips for access-cards, library collections, and high-end transit cards is projected to be $2.5B this year. “We are using graphics printing tools, and today most of the industry is using an older generation chip technology to make RF-ID. They use 0.18 or 0.13 micron node processing on fully-depreciated fabs, and their chips still cost 10-15 cents,” asserted Pavate. “How can they meet demand without building new fabs with tool depreciation adding additional cost?”

Pavate says that general consensus is a 5 cent inflection point could really stimulate demand, but even that cost is too high for a lot of mainstream retail or for a shipper like the US Post Office or FedEx. The US Post Office moves ~260 billion units a year, and can only consider RF-ID tags that are very low cost. “For the type of devices we’re talking about, 20-30 micron linewidths is adequate,” explained Pavate, so printed processes should be more than adequate and allow for additional cost-reductions. “You focus on improving the printing speed, or the web-width.”

Retail and pharmaceutical industries turn inventory several times per year, so they require very short delivery times. Kovio will print chips and/or antennas and then ship those to customers who produce final system for end-users. “These are printing fabs, and the first thing you do with printing is you think about co-locating it,” explained Pavate. “I see a path where large apparel or automotive or pharmaceutical manufacturers would have the RF-ID line next to the current factory.” Kovio will start discussing roadmaps in general by 2Q08, with pilot production planned for 2H08. Stay tuned…the world of silicon IC production just got a lot more interesting.

—E.K.

Labels: CMOS, Kovio, passive, printed, RF-ID, RFID, TFT

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071123: Printed silicon RF-IDs by Kovio

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