Size only matters if you measure it

Words cannot adequately describe my excitement when I first dug into the latest edition of the ITRS and discovered that the idea of process or technology node had been eliminated. It seemed like a dream, but it was driven home when I listened to Alan Allan?s presentation at a Sematech-Semico joint event last January.

The new industry standard for specifying a number to describe an IC technology is to use a real measurement. Manufacturer marketing and industry analysts alike should now devote themselves to eliminating the dangerous and confusing “spin” that has led to so much confusion over the years. When is a “90nm process” not 90nm? What’s the difference between a 70nm and a 73nm NAND process?

For casual industry observers and corporate marketing spin-doctors, there seems to be a tendency to jump on the number with the best ring to it. This mis-information drove the SIA to take a clear stand promoting the use of unambiguous numbers and technology definitions. It makes sense. You measure a real dimension - like the wordline pitch - and translate it to the attainable mask dimension for a repetitive structure which is actually one-half of the pitch. Here is the most important part:

specify the thing you measured.

Unfortunately, the confusion continues. Doubt is cast upon numbers coming from manufacturers and analysts alike. Consider the recent example of the so-called Samsung 60nm NAND*. The product development team published the technology at the 2005 ISSCC ? ?An 8Gb Mult-Level NAND Flash Memory with 63nm STI CMOS Process Technology.?? An actual physical 60nm part makes little sense if you already have 65nm in production. Although Samsung?s press release is not using 60nm in the strict sense of a physical measurement, it does point out that the previous generation of NAND memory was 70nm ? not 65nm.

The most advanced generation of Samsung flash available is 64?1nm as measured from the wordline half-pitch. Semiconductor Insights has analyzed this memory extensively and published several reports on the findings. Semiconductor Insights believes the next stop on the Samsung flash roadmap is 55nm. Will we measure 55 exactly? I would bet against it, but we won?t be calling it 50nm.

It gets tricky when one either disputes or attempts to differentiate independent measurements or specifications that differ by only a few nanometers. Of course, this assumes a certain level of care and expertise on the part of those who publish their measurements. Alas, some analysts have made horrible blunders and produced erroneous measurements while blinded with a preconceived notion about what they would find. I will do my best to keep the numbers published here honest, accurate, and most importantly, unambiguous.

*The newest technology advancement brings 25 percent higher manufacturing productivity over the previous 70nm design technology. The newest technology advancement brings 25 percent higher manufacturing productivity over the previous 70nm design technology.?(Samsung press release, July 19, 2006)

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