Bell Labs Researchers Set Record for
Making Smallest Electronic Device With
Optical Lithography
MURRAY HILL, N.J.--(BUSINESS WIRE)--April 27, 1999--Researchers at Lucent
Technologies' (NYSE: LU - news) Bell Labs have produced the smallest working electronic
device ever made with optical lithography, the technology currently used to manufacture silicon
chips.
The experimental device - a flash memory cell made of silicon -- has features as small as 80
nanometers, which is roughly one-thousandth the width of a human hair.
The Bell Labs research shows that optical lithography could be used to produce more advanced
silicon chips than the semiconductor industry previously had thought. Extending the limits of
optical lithography would result in significant savings for the industry because it would postpone
the costly retooling to a successor technology.
Currently, semiconductor manufacturers are using optical lithography to make silicon-chip
features as small as 180 nanometers, or 0.18 micron. The semiconductor industry had expected
that optical lithography would reach its physical limits at 120 nanometers.
''This achievement provides technology that Lucent's semiconductor business can put to
immediate use in developing future generations of communications integrated circuits, including
ultrafast digital signal processors and high-performance systems-on-a-chip,'' said Mark Pinto,
chief technical officer, Lucent Technologies' Microelectronics Group.
To create the flash memory device with 80-nanometer features, researcher Ray Cirelli and his
colleagues modified how light passes through the mask, which is the master pattern for the
silicon circuit. This approach, known as phase-shift lithography, improved resolution
considerably.
They also developed new resist materials, which are the photosensitive-plastic films on which
the patterns are formed. Recognizing the need to balance the resist's transparency with its
stability during the chip making process, the research team of Om Nalamasu, Frank Houlihan,
and Elsa Reichmanis invented a new class of resists based on cyclo-olefin maleic anhydride
chemistry.
Another key aspect of the Bell Labs research was developing a light-absorbing material
deposited as a thin layer between the resist and the silicon wafer during the early stages of the
process. The material absorbs the light that passes through the resist, reducing any unwanted
reflections from the silicon wafer below.
The resulting flash-memory device, which is a memory device that stores data even when its
power supply is turned off, has a central storage area, or ''floating gate,'' that is 80 nanometers
wide and 160 nanometers long, said researcher Jeff Bude.
To produce the flash memory device, the researchers used 193-nanometer optical lithography.
Today's semiconductor manufacturers, meanwhile, use 248-nanometer optical lithography.
Other Bell Labs researchers involved in the flash memory project included Greg Timp, Bill
Mansfield, Jim Sweeney, Pat Watson, Frieder Baumann, Michael Buonanno, Fred Klemens,
Gary Weber, Jim Sweeney, Gary Forsythe, Dave Barr, John Lee, Conor Rafferty, Steve
Hillenius, Skip Hutton, Bob Vella, Al Timko, and Lloyd Harriott. Allen Gabor of ARCH
Chemicals also was involved. |
