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: Martin Sohn (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 37

Harnessing the extreme ultraviolet for critical dimension metrology

March 17, 2026
Author(s)
Bryan Barnes, Purnima P. Balakrishnan, John Burnett, Aaron Chew, Colton Dudley, Thomas Germer, Steven Grantham, Stephanie Moffitt, Eric Shirley, Martin Sohn, Daniel Sunday
The semiconductor industry has long adopted visible and ultraviolet wavelengths for optical critical dimension (OCD) measurements. Decreasing feature sizes, increasing architecture complexity, and troublesome parametric correlations all motivate approaches

Radial polarization imaging of entangled biphoton state

June 11, 2025
Author(s)
Jiung Kim, Jeeseong Hwang, Martin Sohn
Polarization entanglement of single photons is a key element to enable quantum 2.0 applications such as quantum computing, quantum networks, and quantum sensing. Verification and fidelity assessment of quantum entanglement of single photon pairs correlated

Lab-based multi-wavelength EUV diffractometry for critical dimension metrology

April 24, 2025
Author(s)
Bryan Barnes, Aaron Chew, Nicholas Jenkins, Yunzhe Shao, Martin Sohn, Regis Kline, Daniel Sunday, Purnima Balakrishnan, Thomas Germer, Steven Grantham, Clay Klein, Stephanie Moffitt, Eric Shirley, Henry Kapteyn, MARGARET MURNANE
Background: The industry is developing extreme-ultraviolet wavelength (EUV) techniques to measure critical dimensions (CDs) in logic fabrication. As nascent approaches are unveiled, evaluations against reference metrologies are essential to motivate

Instrument Development for Spectroscopic Ellipsometry and Diffractometry in the EUV

April 24, 2024
Author(s)
Stephanie Moffitt, Bryan Barnes, Thomas A. Germer, Steven Grantham, Eric Shirley, Martin Sohn, Daniel Sunday, Charles S. Tarrio
Semiconductor devices are noted for ever-decreasing dimensions but now are also becoming more complex. While scanning probe microscopy can still resolve the smallest features, it does not have the throughput for high-volume characterization of full wafers

Reflective deep-ultraviolet Fourier ptychographic microscopy for nanoscale imaging

April 29, 2023
Author(s)
Kwanseob Park, Yoon Sung Bae, Sang-Soo Choi, Martin Sohn
Fourier ptychographic microscopy (FPM) that has high space-bandwidth-product and phase imaging capability requires significant resolution enhancement in reflection mode for imaging of nanoscale semiconductor devices. A direct way to nanoscale resolution is

Measurement sensitivity of DUV scatterfield microscopy parameterized with partial coherence for duty ratio-varied periodic nanofeatures

February 1, 2022
Author(s)
Taekyung Kim, Eikhyun Cho, Yoon Sung Bae, Sang-Soo Choi, Bryan Barnes, Richard M. Silver, Martin Sohn
The deep ultraviolet (DUV) scatterfield imaging microscopy technique enables accurate dimensional measurements of periodic nanostructures with sub-nanometer sensitivity to support semiconductor device manufacturing. A parametric sensitivity analysis for

Appraising the extensibility of optics-based metrology for emerging materials

October 4, 2019
Author(s)
Bryan M. Barnes, Mark-Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
To advance computational capabilities beyond conventional scaling limitations, novel device architectures enabled by emerging materials may be required. Optics-based methodologies, central to modern-day process control, will be pursued by the

Assessing form-dependent optical scattering at vacuum- and extreme-ultraviolet wavelengths off nanostructures with two-dimensional periodicity

June 24, 2019
Author(s)
Bryan M. Barnes, Mark Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
Several metamaterials and nanostructures are form birefringent, exhibiting effective refractive index differences for orthogonal polarizations due to the placement of subwavelength features if the periodicity is smaller than the incident wavelength. As the

Assessing the wavelength extensibility of optical patterned defect inspection

March 29, 2017
Author(s)
Bryan Barnes, Hui Zhou, Mark-Alexander Henn, Martin Sohn, Richard M. Silver
Qualitative comparisons have been made in the literature between the scattering off deep- subwavelength-sized defects and the scattering off spheres in free space to illustrate the challenges of optical defect inspection with decreasing patterning sizes

Optimizing Subfield Targets for Nanoscale Quantitative Optical Imaging

September 29, 2016
Author(s)
Mark Alexander Henn, Bryan M. Barnes, Hui Zhou, Martin Y. Sohn, Richard M. Silver
The full 3-D scattered field above finite sets of features has been shown to contain a continuum of spatial frequency information, and with novel optical microscopy techniques and electromagnetic modeling, deep-subwavelength geometrical parameters can be

Enabling Quantitative Optical Imaging for In-die-capable Critical Dimension Targets

April 4, 2016
Author(s)
Bryan M. Barnes, Mark Alexander Henn, Martin Y. Sohn, Hui Zhou, Richard M. Silver
Dimensional scaling trends will eventually bring the semiconductor critical dimensions (CDs) down to only a few atoms in width. New optical techniques are required to address intra-die variability for these CDs using sufficiently small in-die metrology

Quantitative tool characterization of a 193 nm scatterfield microscope

September 9, 2015
Author(s)
Martin Sohn, Bryan Barnes, Hui Zhou, Richard Silver
Optical microscope tool characterization has been investigated for the quantitative measurements of deep sub-wavelength features using a Fourier plane normalization method. The NIST 193 nm scatterfield microscope operating with an ArF Excimer laser, which

Scatterfield Microscopy and the Fundamental Limits of Optical Defect Metrology

April 14, 2015
Author(s)
Richard M. Silver, Bryan M. Barnes, Martin Y. Sohn, Hui Zhou
Defect inspection remains a critical manufacturing challenge due to the competing requirements between throughput and very high resolution. Currently only optical methods provide an acceptable solution, although there are a number of process layers and

Effects of wafer noise on the detection of 20 nm defects using optical volumetric inspection

February 11, 2015
Author(s)
Bryan Barnes, Francois R. Goasmat, Martin Sohn, Hui Zhou, Andras Vladar, Richard Silver
Patterning imperfections in semiconductor device fabrication may either be noncritical [e.g., line edge roughness (LER)] or critical, such as defects that impact manufacturing yield. As the sizes of the pitches and linewidths decrease in lithography

193 nm scatterfield microscope illumination optics

December 17, 2014
Author(s)
Martin Y. Sohn, Richard M. Silver
A scatterfield microscope for deep sub-wavelength semiconductor metrology using 193 nm light has been designed. In addition to accommodating the fixed numerical aperture and size of its commercial catadioptric objective lens, the illumination optics are

Optical volumetric inspection of sub-20 nm patterned defects with wafer noise

April 2, 2014
Author(s)
Bryan M. Barnes, Francois R. Goasmat, Martin Y. Sohn, Hui Zhou, Richard M. Silver, Andras Vladar, Abraham Arceo
We have previously introduced a new data analysis method that more thoroughly utilizes scattered optical intensity data collected during defect inspection using bright-field microscopy. This volumetric approach allows conversion of focus resolved 2-D

Three-dimensional deep sub-wavelength defect detection using (lambda) = 193 nm optical microscopy

October 25, 2013
Author(s)
Bryan M. Barnes, Martin Y. Sohn, Francois R. Goasmat, Hui Zhou, Andras Vladar, Richard M. Silver, Abraham Arceo
Identifying defects in photolithographic patterning is a persistent challenge in semiconductor manufacturing. Well-established optical methods in current use are jeopardized by upcoming sub-20 nm device dimensions. Volumetric processing of focus-resolved

Harnessing 3D Scattered Optical Fields for sub-20 nm Defect Detection

June 24, 2013
Author(s)
Bryan M. Barnes, Martin Y. Sohn, Francois R. Goasmat, Hui Zhou, Richard M. Silver, Abraham Arceo
Experimental imaging at =193 nm of sub-resolved defects performed at several focus positions yields a volume of spatial and intensity data. Defects are located in a differential volume, given a reference, with up to 5x increase in sensitivity.
Was this page helpful?