U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by:

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 60

Nondestructive shape process monitoring of three-dimensional high aspect ratio targets using through-focus scanning optical microscopy Optical Microscopy

September 27, 2018
Author(s)
Ravikiran Attota, Hyeonggon Kang, Keana C. Scott, Richard A. Allen, Andras Vladar, Bunday Benjamin
Low-cost, high-throughput and nondestructive metrology of truly three-dimensional (3-D) targets for process control/monitoring is a critically needed enabling technology for high-volume manufacturing (HVM) of nano/micro technologies in multi-disciplinary

Enhancing optical microscopy illumination to enable quantitative imaging

March 18, 2018
Author(s)
Emil Agocs, Ravikiran Attota
There has been an increasing push to derive quantitative measurements using optical microscopes. While several aspects of microscopy have been identified to enhance quantitative imaging, non- uniform angular illumination asymmetry (ANILAS) across the field

Volume Determination of Irregularly-shaped Quasi-spherical Nanoparticles

September 22, 2016
Author(s)
Ravikiran Attota
Nanoparticles (NPs) are widely used in diverse application areas, such as medicine, engineering, and cosmetics. The size (or volume) of NPs is one of the most important parameters for their successful application. It is relatively straightforward to

Nanoparticle size determination using optical microscopes

October 27, 2014
Author(s)
Ravikiran Attota, Richard J. Kasica, Premsagar P. Kavuri, Hyeong G. Kang, Lei Chen
We present a simple method for size determination of nanoparticles using conventional optical microscopes. The method, called through-focus scanning optical microscopy (TSOM), makes use of the four-dimensional optical information collected at different

Through-focus scanning optical microscopy for defect inspection of EUV masks

August 12, 2013
Author(s)
Ravikiran Attota, Vibhu Jindal
The TSOM method provides three-dimensional nanoscale metrology using a conventional optical microscope. Substantial improvements in defect detectability using the TSOM method will be presented. The TSOM method shows potential to (i) detect phase defects on

TSV Reveal height and bump dimension metrology by the TSOM method

April 30, 2013
Author(s)
Ravikiran Attota, Haesung Park, Victor H. Vartanian, Ndubuisi G. Orji, Richard A. Allen
Through-focus scanning optical microscopy (TSOM) transforms conventional optical microscopes into truly 3D metrology tools for nanoscale- to- microscale dimensional analysis with nanometer-scale sensitivity. Although not a resolution enhancement method

Use of TSOM for sub-11 nm node pattern defect detection and HAR features

April 30, 2013
Author(s)
Ravikiran Attota, Abraham Arceo, Bunday Benjamin
In-line metrologies currently used in the semiconductor industry are being challenged by the aggressive pace of device scaling and the adoption of novel device architectures. In defect inspection, conventional bright field techniques will not likely be

TSV REVEAL HEIGHT AND BUMP DIMENSION METROLOGY BY THE TSOM METHOD: FROM NANOMETER TO MICROMETER SCALE

January 23, 2013
Author(s)
Ravikiran Attota, Victor Vertanian, Steve Olson, Robert Edgeworth, Iqbal Ali, Craig Huffman, Pate Moschak, Harry Lazier, Elizabeth Lorenzini
The exceptional z-height resolution of TSOM, as well as very fast measurement time, is particularly important for high volume manufacturing. These two attributes make TSOM advantageous for 3D-stacked IC measurements of TSV reveal structures, and C4 bumps