21st century challenges for test and measurement

June 1, 2004
Test and measurement, where military and aerospace systems are concerned, is at a critical stage, the dimensions of which cannot be understated, and the ramifications of which cannot be underestimated.

By John Keller, Chief Editor

Test and measurement, where military and aerospace systems are concerned, is at a critical stage, the dimensions of which cannot be understated, and the ramifications of which cannot be underestimated. Electronic-circuit designers are steadily pushing beyond nanometer-scale integration in their continuing quest to shrink electronic components, and this places an increasing and crushing burden on test and measurement experts.

I remember not so very long ago when the holy grail of circuit designers involved shrinking circuits to submicron size for integrating on ever-more-complex chips. In those days people tried to drive home the miniscule size of integrated-circuit geometries by equating them with the size of a human hair.

These days that description simply doesn't work anymore; as integrated circuits have evolved and shrunk, it would be like comparing the size of a housefly to a bulldozer.

Humans have difficulty seeing things smaller than 40 microns. Consider that a human hair is about 50 to 70 microns thick; a pollen spore is 30 to 50 microns in diameter; a talcum powder granule is about 10 microns across, and a red blood cell is about 8 microns across. We're still not getting close to today's circuits.

Microelectronics designers crossed the threshold of submicron circuits about a decade ago. A 1-micron circuit is about half the size of a human red blood cell. Today's most advanced circuits are about 900 nanometers across, and typical circuits are about 0.15 to 0.18 microns across. The smallest devices are roughly 20 times smaller than a red blood cell.

Today's circuits are not only about the sizes of viruses, but their numbers on each chip are increasing exponentially.

John Culp is marketing manager for defense and space electronic systems at Honeywell Aerospace Electronic Systems in Plymouth, Minn. Culp's group is one of the world's centers of excellence for designing and fabricating advanced electronic devices that are able to resist the effects of radiation.

Honeywell's radiation-hardened fabs in Minnesota are starting to move from 0.35-micron and 0.25 micron circuit sizes to 0.15 micron. Not only does this shrink chip densities, but it also increases device speed, and enables designers to increase the number of circuits they can put on a chip from about 4 million to between 10 million and 15 million.

Some engineers look at those numbers and imagine the new capabilities that all those circuits will bring to the table. Test-and-measurement engineers, however, look at those numbers and imagine how many things there are now that could go wrong in these modern tightly integrated chips.

Test engineers are hard-pressed to come up with software routines to put these new integrated circuits through their paces to determine where the devices may have problems. It's more important now than it has ever been because devices like Honeywell's don't exactly go into desktop PCs.

Honeywell and other designers of radiation-hardened integrated circuits build devices for crucial intelligence satellites, strategic communications networks, commercial jetliners, and even nuclear-tipped intercontinental ballistic missiles. In short, Honeywell designs circuits that have to work. Period.

The task of testing these new generations of tiny integrated circuits is a huge one, but fortunately companies such as Mentor Graphics in Wilsonville, Ore.; National Instruments, in Austin, Texas; ManTech International of Fairfax, Va.,; Symmetricom, of San Jose, Calif.; and Agilent in Loveland, Colo., are stepping up to the plate.

This month Military & Aerospace Electronics Senior Editor Ben Ames takes an in-depth look at the latest trends in test and measurement. His story appears on page 28.

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