Home > Press > Nanoscale Dimensioning Is Fast, Cheap with New NIST Optical Technique
![]() |
This schematic (left) shows how a TSOM image is acquired. Using an optical microscope, several images of a 60 nanometer gold particle sample (shown in red) are taken at different focal positions and stacked together. The computer-created image on the right shows the resultant TSOM image.
Credit: NIST |
Abstract:
A novel technique* under development at the National Institute of Standards and Technology (NIST) uses a relatively inexpensive optical microscope to quickly and cheaply analyze nanoscale dimensions with nanoscale measurement sensitivity. Termed "Through-focus Scanning Optical Microscope" (TSOM) imaging, the technique has potential applications in nanomanufacturing, semiconductor process control and biotechnology.
Optical microscopes are not widely considered for checking nanoscale (below 100 nanometers) dimensions because of the limitation imposed by wavelength of light—you can't get a precise image with a probe three times the object's size. NIST researcher Ravikiran Attota gets around this, paradoxically, by considering lots of "bad" (out-of-focus) images. "This imaging uses a set of blurry, out-of-focus optical images for nanometer dimensional measurement sensitivity," he says. Instead of repeatedly focusing on a sample to acquire one best image, the new technique captures a series of images with an optical microscope at different focal positions and stacks them one on top of the other to create the TSOM image. A computer program Attota developed analyzes the image.
While Attota believes this simple technique can be used in a variety of applications, he has worked with two. The TSOM image can compare two nanoscale objects such as silicon lines on an integrated circuit. The software "subtracts" one image from the other. This enables sensitivity to dimensional differences at the nanoscale—line height, width or side-wall angle. Each type of difference generates a distinct signal.
TSOM has also been theoretically evaluated in another quality control application. Medical researchers are studying the use of gold nanoparticles to deliver advanced pharmaceuticals to specific locations within the human body. Perfect size will be critical. To address this application, a TSOM image of a gold nanoparticle can be taken and compared to a library of simulated images to obtain "best-match" images with the intent of determining if each nanoparticle passes or fails.
This new imaging technology requires a research-quality optical microscope, a camera and a microscope stage that can move at preset distances. "The setup is easily under $50,000, which is much less expensive than electron or probe microscopes currently used for measuring materials at the nanoscale," Attota explains. "This method is another approach to extend the range of optical microscopy from microscale to nanoscale dimensional analysis." So far, sensitivity to a 3 nm difference in line widths has been demonstrated in the laboratory.
* R. Attota, T.A. Germer and R.M. Silver. Through-focus scanning-optical-microscope imaging method for nanoscale dimensional analysis, Optics Letters 33, 1990 (2008).
####
About NIST
Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Department of Commerce. NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
For more information, please click here
Contacts:
Evelyn Brown
(301) 975-5661
Copyright © NIST
If you have a comment, please Contact us.Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.
Related News Press |
News and information
New organic molecule shatters phosphorescence efficiency records and paves way for rare metal-free applications July 5th, 2024
Single atoms show their true color July 5th, 2024
New method cracked for high-capacity, secure quantum communication July 5th, 2024
Searching for dark matter with the coldest quantum detectors in the world July 5th, 2024
Imaging
Single atoms show their true color July 5th, 2024
Discoveries
Efficient and stable hybrid perovskite-organic light-emitting diodes with external quantum efficiency exceeding 40 per cent July 5th, 2024
A New Blue: Mysterious origin of the ribbontail ray’s electric blue spots revealed July 5th, 2024
New organic molecule shatters phosphorescence efficiency records and paves way for rare metal-free applications July 5th, 2024
Single atoms show their true color July 5th, 2024
Announcements
New organic molecule shatters phosphorescence efficiency records and paves way for rare metal-free applications July 5th, 2024
Single atoms show their true color July 5th, 2024
New method cracked for high-capacity, secure quantum communication July 5th, 2024
Searching for dark matter with the coldest quantum detectors in the world July 5th, 2024
Tools
Single atoms show their true color July 5th, 2024
Atomic force microscopy in 3D July 5th, 2024
![]() |
||
![]() |
||
The latest news from around the world, FREE | ||
![]() |
![]() |
||
Premium Products | ||
![]() |
||
Only the news you want to read!
Learn More |
||
![]() |
||
Full-service, expert consulting
Learn More |
||
![]() |