Hitachi’s tiny mu-chip

Already the world’s smallest RFID chip, SOI makes the next generation far thinner than a piece of paper – while radically increasing productivity.

The next generation of Hitachi’s µ-chip (mu-chip) is poised to make a major impact on the RFID (radio frequency identification) world. Presented at the IEEE conference in February 2006, this latest version of the world’s smallest RFID chip is based on SOI technology. The result is a chip so small, so thin, that it easily leaves the others behind by at least two generations.
How small is small? Consider it this way. The µ-chip that has been in mass production since 2001 measures 0.4mm on a side – so you could hide it comfortably under a grain of salt.
The newest generation µ-chip on SOI measures 0.15mm on a side – so you could hide about a dozen of them under that same grain of salt.

How thin is thin? The current generation is 60 microns thick – about three-quarters as thick as a piece of paper, which is typically about 80 microns thick. The new generation on SOI is only 7.5 microns thick – so a stack of 10 would still be less thick than a piece of paper.
For Hitachi, these SOI-enabled smaller dimensions translate into two very important advantages:
1. Substantially lower cost of ownership.
With SOI, each device is surrounded by insulator, preventing interference between devices and enabling higher integration on an even smaller area. With the smaller chips, more fit on a wafer – in this case as much as seven times as many. That makes for dramatically lower manufacturing costs – which could potentially enable the company to break the 5-cent barrier that analysts say is needed to really launch the RFID revolution.

2. The ability to embed the chips in paper.
This opens the door to a whole new realm of applications. Anywhere paper and security considerations intersect, the new µ-chip is a very attractive contender. The extreme thinness was achieved by completely removing the supporting silicon layer, leaving only the top silicon layer in which the circuit is fabricated, and the layer of insulation beneath it.

The µ-chip is being used for animal tagging in East Asia to ensure traceability in the food supply chain. (Courtesy of Hitachi America)

Lowering costs

Until now, cost has been a major impediment to large-scale RFID deployment. The current generation µ-chip plus antenna was selling in the 10- to 15-cent range. With the massive increase in productivity enabled by the smaller chip, Hitachi should be well positioned to bring prices down further.
Says Sarah LoPrinzi, BCC Research Analyst and author of “RFID: Technology, Applications and Market Potential” (August 2006), “Hitachi’s recent announcement of the next generation of µ-chips resolves some of the technical and economic chip manufacturing issues that have impeded the development of low cost RFID tags. In the RFID industry, the magical cost-per-tag is widely thought to be $0.05/tag. Once the $0.05 barrier is overcome, item-level inventory control becomes more realistic.”

Put it in the paper

The new, ultra-thin µ-chip opens the doors to a wider range of paper-based applications, acting as an “intelligent watermark”.

As Mark Roberti, editor-in-chief of the RFID Journal, told ASN, “The value in having an ultra-thin RFID tag is that companies can embed the tag in packaging materials for product authentication and anti-counterfeiting applications without worrying that the transponder will be so visible as to make the packaging unattractive.” Retail gift certificates, labels and other paper documents would benefit from enhanced security.

To help fight counterfeiting and improve supply-chain management, Winwatch of Switzerland has IP for embedding RFID chips such as the µ into the glass, hands or axis of high-end watches. (Courtesy of Winwatch)

An obvious application might seem to be banknotes, but this is probably not for the very near-term. While embedding the newest ultra-thin µ-chip in paper currency is now entirely feasible from a technical standpoint, there still remain issues for government and public debate regarding privacy and security in the supporting infrastructure design.

But with both businesses and governments looking for more reliable, cost-effective electronic solutions for managing supply chains and preventing fraud, the tiny µ-chip should be a major player.

* Concept: Read the technical description on the Hitachi website

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