Getting physical

Mechanical Engineering, Dec 2000 by Wolcott, Barbara

In the business of testing ideas, Lawrence Livermore relies on mechanical engineers to translate the abstract into the concrete.

LAWRENCE LIVERMORE NATIONAL Laboratory is named for a physicist, the atom-splitter Ernest Orlando Lawrence, but from its earliest years, the lab's work has moved forward on the wheels of mechanical engineering as much as on the power of nuclear physics.

The 7,600 employees at the lab could make up the population of a small town, and one of the biggest segments, numbering in the hundreds, consists of mechanical engineers.

Among the laboratory's current research and development projects is an effort to shape the next generation of integrated circuits. Researchers are talking about reducing sixfold the scale of features that can be rendered in silicon, from about 180 nanometers now, down to about 30. More than a third of the research team members are mechanical engineers, who are doing the precision engineering, such as building systems that will hold optics in alignment to micron tolerances. They are doing metrology on surfaces to measure errors smaller than a nanometer.

"What they have done," said Don Sweeney, the chief technical officer for the project, "is to make the world's most accurate optics machine."

Although Livermore's primary work is research in physics, it is mechanical engineering that moves theory into practical application.

Retired mechanical engineer Jim Bryan worked at Livermore Laboratory nearly since it was founded. He remembers when physicists were pessimistic about the possibility of building small nuclear devices capable of being fired from conventional artillery. Bryan said the prevailing belief at the time was that close tolerances necessary to manufacture such a device would be impossible or too expensive to achieve. The Livermore Laboratory proved that it could be done, leading to the advent of the nuclear submarine fleet and a dazzling array of small warheads, communications systems, and field weapons.

Much of that work became reality because Jim Bell, the laboratory's chief engineer, who had worked with Lawrence on the Manhattan Project, had the foresight to organize a precision engineering group under Bryan.

A mechanical engineer when he came to work for Livermore, Bryan ended up working for the Physics Department. "I came in 1955 and the laboratory was already about two years old," Bryan said. "It was a wonderful place to work. Lawrence was the boss, even though he never gave himself a title. I eventually discovered that Lawrence had enormous respect and prestige in Washington, D.C. It was rumored that he had direct access to five presidents."

Bryan recalled a story that occurred at Lawrence's Berkeley lab before World War II. When an engineer, Bill Brobeck, asked if he could work with him, Lawrence questioned the need for an engineer, because the prevailing scientific paradigm at the time was that physicists could do everything with the help of technicians.

Brobeck's 11 o'clock meeting with Lawrence had been delayed, and the physicist had suggested that the engineer tour the facility. During the interview that afternoon, after seeing one patched setup after another put together with baling wire and electrical tape, Brobeck was able to politely point out some deficiencies that engineers could remedy.

"Lawrence had been criticized for not being able to reproduce his physics experiments because of machine failures," Bryan recalled, "and he realized that Brobeck was probably correct." Lawrence hired Brobeck, an independently wealthy man, for a dollar a year, and began a new partnership of two disciplines that would put the Lawrence Berkeley and Lawrence Livermore labs in the fast lane.

The laboratory's work for the US. Department of Energy and the military has found its way into the private sector. Technology transfer includes developments in computer-assisted design and manufacturing, and miniaturized radar for security systems.

Now the lab's precision engineering has leapfrogged from the nuclear arsenal to the public sector, with the development of a cutting-edge manufacturing system for producing computer chips.

NEXT-GENERATION LITHOGRAPHY

One of the key steps necessary to keep making features smaller and smaller on integrated circuits is to improve the resolution of the lithographic manufacturing process. It is estimated in the computer industry that there are four generations of computer chips left for silicon, and a fabrication process called extreme ultraviolet lithography, or EUVL, is a promising candidate for these future generations.

Not only has technology had to make it feasible to manufacture each generation of computer chips, but the method must also be cost effective to be commercially viable. Intel Corp. believed the national laboratories could accomplish the task and joined with four other integrated circuit manufacturers to fund the work.

Intel, AMD, Motorola, Infineon, and Micron Technology formed a holding company, EUV Limited Liability Co. Roughly a quarter-billion dollars from this group is funding work at three national labs together-Sandia, Lawrence Berkeley, and Lawrence Livermore-to develop the technology for producing the next generation of computer chips.