Device features on computer chips as small as 40 nm can now be measured reliably thanks to a new test structure developed by the National Institute of Standards and Technology. The new test structures are the product of NIST’s more than four-year effort to provide standard “rulers” for measuring the narrowest linear features that can be controllably etched into a chip. The NIST rulers are precisely etched lines of crystalline silicon ranging in width from 40 nm to 275 nm. The spacing of atoms within the box-like silicon crystals is used like hash marks on a ruler to measure the dimensions of the test structures.

Industry can use the reference materials to calibrate tools to reliably measure microprocessor-device gates and similar items.

“We have caught up to the semiconductor industry roadmap for linewidth reference-material dimensions with this work,” says Richard Allen, a NIST researcher who helped develop the standard. “With the semiconductor industry, one has to run at full speed just to keep up.”

For more information, visit www.nist.gov.