Santa Cruz, Calif. -- Nanometer ICs are more manufacturable today thanks to research directed by Thomas Kailath, emeritus professor of engineering at Stanford University. IEEE last week picked Kailath as recipient of its highest award, its annual Medal of Honor.

Kailath, who pioneered phase-shift mask technology for IC lithography, also co-founded design-for-manufacturability (DFM) startups Numerical Technologies Inc. and Clear Shape Technologies Inc. His 45-year career extends much further, however, encompassing research in such topics as information theory, signal processing, linear systems, VLSI design and sensor array processing.

The IEEE Medal of Honor acknowledges an exceptional contribution to or extraordinary career in an IEEE field of interest. This year the institute is honoring Kailath for his contributions to communications, computing, control and signal processing. He will receive the award in a June ceremony in Philadelphia.

"I'm very pleased and very honored," Kailath said. "It's very much a collective honor. We have a wonderful collection of students and postdocs [at Stanford], and it reflects on all of us." Kailath has mentored more than 100 doctoral and postdoctoral students, and he has authored or co-authored more than 300 papers.

Kailath received his doctor of science in electrical engineering from the Massachusetts Institute of Technology in 1961. After a short stay at the Jet Propulsion Laboratory, he joined Stanford less than two years later, becoming a full professor in 1968. Kailath said he has retired from classroom teaching and is mostly working on writing projects these days.

"Thomas Kailath is one of the most influential electrical engineers of our time," said Vincent Poor, dean of engineering and applied science at Princeton University, who nominated Kailath for the IEEE award. "He has made many fundamental contributions to the field, and they have had a widespread effect on many aspects of electrotechnology, ranging from communications to semiconductor manufacturing and signal processing."

Kailath is first and foremost a "mathematical engineer," said Poor, and his work is "very profoundly and deeply steeped in fundamental math." One example is semiconductor manufacturing, where, Poor said, Kailath "came up with a radically new solution to the problem based on mathematical principles."

In the 1990s, Kailath was persuaded by a mathematician at the Defense Ad- vanced Research Projects Agency to look into the IC manufacturing problem. The first challenge was the need to quickly heat wafers to 1,000°C and cool them down again. People were trying to get uniform heat flux over the wafer, but Kailath and his students showed mathematically that it was the wrong approach. They came up with an algorithm to adjust the heat at different points on the wafer.

Tackling lithography
Then came a bigger problem. "In 1995, we thought that lithography would be a challenging area," Kailath said. "At the time it looked like we would not be able to go below 100 nanometers with optics. We felt [we could tackle the problem] by using a technology that had come up in the early 1980s" called phase shifting."

Phase shift masks use the interference caused by phase differences to print patterns correctly on the wafer. Kailath and his students undertook research showing that phase shift techniques, previously used for simple patterns, could work for complex geometries.