Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NIST unveils atom-based standards

25.02.2005


The large purple rectangle in this colorized image is a chip feature about 40 by 150 nanometers in size, surrounded by encapsulating material. The magnified section shows the planes of silicon atoms used to calibrate feature measurements. Photo courtesy NIST


Device features on computer chips as small as 40 nanometers (nm) wide--less than one-thousandth the width of a human hair--can now be measured reliably thanks to new test structures developed by a team of physicists, engineers, and statisticians at the Commerce Department’s National Institute of Standards and Technology (NIST), SEMATECH, and other collaborators. The test structures are replicated on reference materials that will allow better calibration of tools that monitor the manufacturing of microprocessors and similar integrated circuits.

The new test structures are the culmination of NIST’s more than four-year effort to provide standard "rulers" for measuring the narrowest linear features that can be controllably etched into a chip. The NIST rulers are precisely etched lines of crystalline silicon ranging in width from 40 nm to 275 nm. The spacing of atoms within the box-shaped silicon crystals is used like hash marks on a ruler to measure the dimensions of these test structures. Industry can use these reference materials to calibrate tools to reliably measure microprocessor-device gates, for example, which control the flow of electrical charges in chips.

"We have caught up to the semiconductor industry roadmap for linewidth reference-material dimensions with this work," says Richard Allen, one of the NIST researchers involved in the project. "With the semiconductor industry, one has to run at full speed just to keep up."



The new reference materials, configured as a 9 millimeter (mm) by 11 mm chip embedded in a silicon wafer, are now being evaluated by SEMATECH member companies. Compared to a batch of prototype test structures produced by NIST in 2001, the new reference materials offer a wider range of reference feature sizes, including some that are much narrower, and they are measured much more precisely (with uncertainties of less than 2 nm compared to 14 nm previously). In the absence of reference materials such as these, companies have calibrated measurement tools using in-house standards, which may neither be accurate nor agree with each other.

The new materials will be publicly unveiled at a workshop cosponsored by NIST and SEMATECH on March 2, in conjunction with an SPIE (International Society for Optical Engineering) meeting in San Jose, California. SEMATECH member companies have been invited to present the results of their evaluations of the prototype test structures at this meeting. The test structures could be distributed as NIST-traceable artifacts to end users in the semiconductor industry for development of metrology tools, or a private company could manufacture and distribute test structures based on the NIST technology.

The new silicon reference materials are the outcome of a series of technical and procedural innovations. First, rows of rectangular features are etched into a particular type of silicon wafer in which atoms are arranged in a regular lattice design. The features are about 150 nm high, arrayed in sets of six features, each with a different width. The lattice has extremely even edges, but NIST modified the etching process to make the sides of the features even smoother, which helped to improve measurement precision.

Using four different types of microscopes--optical, scanning electron (SEM), atomic force (AFM), and high-resolution scanning transmission microscopes (HRTEM)--the silicon reference features are first screened to identify those with the approximate right dimensions, and then very carefully measured. A key step in the calibration process involves passing a beam of electrons through the silicon lines to a detector. Alternating dark and light parallel lines on the detector mark where columns of silicon atoms diffract the electrons. Technicians then manually counted these marks. From this count, the dimension of the reference feature can be calculated, because the number of lines in the image matches the number of silicon atoms in the crystal, whose spacing is always exactly the same and is traceable to the international standard of length. These data can then be used to calibrate measurements by other microscope tools.

The program was a collaboration between NIST, SEMATECH, VLSI Standards Inc., San Jose, Calif. and Accurel Systems International Corp., Sunnyvale, Calif. NIST researchers handled the layout, etching, AFM imaging, and lattice plane counting tasks; a key step in the patterning of the silicon lines in the test structures was performed by VLSI Standards; the SEM imaging was performed by SEMATECH and NIST; and the HRTEM imaging was performed by Accurel Systems.

As a non-regulatory agency of the U.S. Department of Commerce’s Technology Administration, NIST develops and promotes measurement, standards and technology to enhance productivity, facilitate trade and improve the quality of life.

The members of SEMATECH cooperatively set global industry direction and accelerate technology solutions in infrastructure, lithography, materials, and manufacturing to ensure a strong and vibrant semiconductor industry.

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Materials Sciences:

nachricht Physics, photosynthesis and solar cells
01.12.2016 | University of California - Riverside

nachricht New process produces hydrogen at much lower temperature
01.12.2016 | Waseda University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>