Jan 02, 2006Back in September 2003, Matrics, a startup company selling Gen 1 Electronic Product Code technology, announced it had developed a new high-speed radio frequency identification tag assembly machine called PICA (Parallel Integrated Chip Assembly), which could produce 70 billion RFID tags a year (see New High-Speed RFID Tag Machine). PICA was meant to compete with rival Alien Technology’s Fluidic Self Assembly technology, which flows microchips into straps that can be quickly attached to antennas.
More than two years later, PICA is still not churning out tags, because the machine failed to provide a high enough yield of tags that functioned properly. However, Symbol Technologies, the company that purchased Matrics in July 2004, says design flaws have been fixed and PICA should be online by the middle of 2006.
“We spent the first quarter of 2005 trying to tune performance of that design,” says Larry Blue, vice president and general manager of Symbol's radio frequency identification tag business. “We got to about 75 percent yield, and that was about as good as we could do. There were some fundamental design problems with the machine.”
Most existing inlay assembly machines attach one chip to one antenna at a time. PICA was designed to assemble a row of inlays simultaneously; with smaller antenna designs, a greater number of inlays per row could be assembled at a time. One of the main problems with the machine was precisely aligning the microchips with preprinted antennas. The root of the dilemma was a component that used a computer and optical sensors to control gears to shift the inlays to the left or right, or slightly forward or backward, to ensure the chip was placed precisely.
In September 2004, Matrics said it had begun using the PICA machine to produce tags (see Matrics Unveils PICA Assembly). However, Blue says its inlay-aligning component was not yet precise enough to enable mass production with a high yield, so it was redesigned. Another issue involved a component that punched the microchips from a release tape down onto the antenna. The chips were not releasing properly, so that component was also changed.
The new configuration was set up in early November, and the initial results were encouraging, according to Blue. “We expect to go into production in the second half of 2006,” he says. “That will let us [meet additional demand] if it picks up in the second half.”
Another benefit, Blue says, is that the machine attaches the chip directly to the antenna. He claims that attaching chips to straps, and straps to antennas, results in a lower yield because a certain percentage of straps will be inoperable. It also causes a less consistent performance, since the chance of an imperfect electrical bond between the chip and antenna is twice as great when two connections are used as with a strap construction. “We think having a single attachment is an advantage,” says Blue. “Also, the PICA system has a small footprint and is modular. That allows you to move inlay production to wherever tags are needed.”
Blue reports that in the first quarter of 2006, Symbol will stop producing tags that have antennas printed with silver ink, and will instead use etched aluminum antennas. The latter are cheaper than either etched copper antennas or silver ink antennas, and pose fewer environmental issues. The process of etching copper produces toxic waste, and silver ink antennas cannot be put in landfills in certain jurisdictions due to fears that the metal will leach into the ground water.
Aluminum is not as conductive as copper, Blue says, but the surface flatness of the aluminum antenna leads to lower electrical resistance and parasitics (unintended resistance, capacitance and inductance that can affect the frequency and amplitude of the received RF signal, leading to poorly performing tags). As a result, he says, the performance of aluminum antennas is about the same for copper.
Copper does have other advantages over aluminum, he adds. Oxide, for instance—which can impede a tag’s performance—doesn’t build up as quickly on copper as it does on aluminum. Blue reports that Symbol has developed a coating to prevent the buildup of oxide on the antenna.
