With the July 9, 2003 issue, we combined under one title
two NIST newsletters, NIST
Update and NIST TechBeat. We’ve made the change
to help improve the timeliness of our topics. Our goal is to
topics tied to publication of peer-reviewed papers, conference
presentations, and other timely “news hooks” as often
as possible. We also will be including photos and graphics whenever
We hope you like the new look! Please let me know if you have
any comments or suggestions.
Gail Porter, email@example.com
NIST TechBeat Editor
To Help Manufacturers Measure Micromachine Properties
a car collides with another car, a tiny device called an
accelerometer detects the change in motion and sets off
an air bag, an innovation that has saved many lives.
accelerometer is one of the most common uses of microelectromechanical
systems (MEMS), but scientists and engineers also are starting
to use them in devices ranging from angioplasty pressure
sensors and pacemakers to optical disk drives.
also known as micromachines, are a relatively new technology
that uses existing microelectronics manufacturing methods to
create complex machines with micrometer feature sizes. MEMS
devices represent a rapidly growing component of the semiconductor
industry. Many micromachines contain moving parts that are combined
with integrated circuits. Like most high-tech devices, they
must be made with precise dimensions and materials properties
to operate properly. To help manufacturers ensure that their
devices meet these exacting specifications, National Institute
of Standards and Technology scientists and engineers helped
develop three ASTM International standard test methods for the
thin films used to make micromachines.
The test procedures, which are the first such standards
in the world, will be published in The Annual Book
of ASTM International
Standards this month. The standards are expected to facilitate
global commerce in MEMS technologies by enabling measurements
that will lead to the development of more reliable and
reproducible MEMS devices. The three standards provide
for measuring thin-film dimensions and "strain," a
property related to the stress in the thin film. NIST researchers
have created a Web site to help semiconductor manufacturers
perform the complex mathematical calculations required by the
new standard test methods. For further information, see www.eeel.nist.gov/812/test-structures.
Bulman, (301) 975-5661
Lenses' May Shrink
Feature Sizes on Microchips
data from the National Institute of Standards and Technology
(NIST) will assist in the design of optics for liquid immersion
lithography, an old idea
that recently has attracted new interest as a possible means of improving image
resolution and thereby shrinking feature sizes of computer chips.
Conventional optical lithography has advanced sufficiently
to achieve a resolution of 100 nanometers (billionths
of a meter), but there are physical and technical
limits to how much better it can get. By placing certain liquids between the
final optical element and the silicon wafer, it may be possible to extend the
resolution to 65 nanometers for state-of-the-art lithography using the 193-nanometer
wavelength of light, or even 45 nanometers or below for future systems using
the 157-nanometer wavelength.
A key characteristic
of liquids to be used in immersion lithography is their refractive
index, which affects how light bends as it crosses an interface,
such as that between the liquid and a lens or a silicon wafer.
Air has an index close to one. By contrast, water has a refractive
index almost 50 percent higher. Placing this higher-index
fluid between the lens and the silicon wafer reduces the
resolution-limiting effects of diffraction, enabling imaging
of smaller feature sizes.
physicists recently presented preliminary measurements of
the refractive index for high-purity water, considered
the best candidate for a "liquid lens" at
the 193-nanometer wavelength. They also determined
that the index is very sensitive
to temperature changes, a critical issue for optics design.
A forthcoming paper describes the techniques used to make
these technically difficult measurements.* Future work
on refining these measurements and collecting data on other
liquids that may be useful in 157-nanometer lithography.
John H., and Simon Kaplan. In press. "Measurement
of the refractive index and thermooptic coefficient of water
near 193 nanometers." To appear in Proceedings
of SPIE Optical Microlithography XVI (2003) 5040-188.0
Ost, (301) 975-4034
methods of recognizing a person based on physiological or behavioral
characteristics are expected to play an increasing role in arenas ranging from
international border management to airport security. These biometric systems
use technologies such as fingerprint matching, face recognition or iris identification.
showcase recent advances in the field and examine technological
and security issues facing the biometrics industry, the
Biometrics Consortium Conference 2003
will be held Sept. 22-24, 2003, in Arlington, Va. The conference is sponsored
by the National Institute of Standards and Technology (NIST), along with seven
other federal, state and non-profit agencies that form the consortium.
will include executives from the biometrics industry, university
researchers and representatives of federal agencies such as
NIST, the National Security Agency and the Department of Homeland
conference will include a special session on research that
will address topics such as the societal and political implications
of deploying biometric systems, ways to measure effectiveness
of various technologies and the challenges raised by countermeasures
and spoofing. Other topics will include how biometric systems
are starting to be deployed in some elementary and high schools,
the role of biometrics in enhancing homeland security and transportation
security, real world applications, interoperability, privacy,
testing and evaluation, and security.
More than 70 biometric technology exhibits will be included
at the conference, which will be held at the Hyatt Regency
For conference information and to register online, go to
Due to increased security at federal conferences, attendees
must register in advance and produce photo identification
to be admitted.
Bulman, (301) 975-5661
Puts High-Speed Chips On the Fast Track
A new type of standard to be issued by the National Institute
of Standards and Technology (NIST) this summer will help
need for speed in semiconductors.
reference material" is designed to help
users calibrate instruments that determine the germanium fraction
in silicon-germanium thin films, now used in the conducting channels
of high-speed semiconductors for computers. By measuring the
composition of the standard material and comparing their
results to NIST's
values as part of the instrument calibration process, users can
reduce measurement uncertainty and optimize thin film compositions
with just the right amount of germanium. Germanium causes strain
in the silicon lattice, allowing electrons to move faster and thereby
increasing device operating speed as much as twofold.
new standard—which consists of sets of thin films of
varying compositions—is among the first to be developed
between industrial participants, who supply and characterize
the materials, and NIST staff, who coordinate the process,
conduct additional measurements and tests, and assign values.
The process is less rigorous than the traditional Standard
Reference Material (SRM) approach and may not result in certified
values. But interactive materials can be made available relatively
quickly, just 1 to 2 years after a need is identified, compared
to about 5 years for a new SRM.
need for the silicon-germanium standard was identified at an
industry workshop 2 years ago.
The uncertainty of
compositional measurements currently is limited by available
to about 5 percent; the new standard has been measured with
uncertainty of about 1 percent.
Ost, (301) 975-4034
Investigative Team Describes Progress
been five months since the February 2003 fire at The Station
nightclub in West Warwick, R.I., left 100 dead and some
others injured. Many questions have arisen in the tragedy's
aftermath about the behavior of the smoke and fire, the
manner in which the nightclub was evacuated, and the most probable
cause of the building's failure. NIST's ongoing technical
investigation of the Rhode Island nightclub fire is making
progress toward finding the answers that will lead to recommendations
on how to improve the structural fire safety of similar
A recent statement from the agency updates the status of
the effort. The document, along with other information
(including the complete investigation plan), may be found at
E. Newman, (301) 975-3025
Baldrige Winners Share Tips: Senior leaders from
organizations selected for the Malcolm Baldrige National Quality
Award, including the first winners in health care and education,
will share their best practices at conferences in Cincinnati,
Ohio, on Sept. 23, and Scottsdale, Ariz., on Oct. 9. For more
information and to register online, go to http://baldrige.nist.gov/2003_Regionals/Regionals.htm.