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Title: Nanoscale x-ray imaging of circuit features without wafer etching

Abstract

Modern integrated circuits (ICs) employ a myriad of materials organized at nanoscale dimensions, and certain critical tolerances must be met for them to function. To understand departures from intended functionality, it is essential to examine ICs as manufactured so as to adjust design rules ideally in a nondestructive way so that imaged structures can be correlated with electrical performance. Electron microscopes can do this on thin regions or on exposed surfaces, but the required processing alters or even destroys functionality. Microscopy with multi-keV x-rays provides an alternative approach with greater penetration, but the spatial resolution of x-ray imaging lenses has not allowed one to see the required detail in the latest generation of ICs. X-ray ptychography provides a way to obtain images of ICs without lens-imposed resolution limits with past work delivering 20–40-nm resolution on thinned ICs. We describe a simple model for estimating the required exposure and use it to estimate the future potential for this technique. Here we show that this approach can be used to image circuit detail through an unprocessed 300-μm-thick silicon wafer with sub-20-nm detail clearly resolved after mechanical polishing to 240-μm thickness was used to eliminate image contrast caused by Si wafer surface scratches.more » Here, by using continuous x-ray scanning, massively parallel computation, and a new generation of synchrotron light sources, this should enable entire nonetched ICs to be imaged to 10-nm resolution or better while maintaining their ability to function in electrical tests.« less

Authors:
 [1];  [2];  [3];  [3];  [3];  [4];  [4];  [5];  [6];  [7]
  1. Northwestern Univ., Evanston, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
  2. Northwestern Univ., Evanston, IL (United States)
  3. Argonne National Lab. (ANL), Argonne, IL (United States)
  4. Univ. of Southern California, Los Angeles, CA (United States)
  5. Intel Corp., Hillsboro, OR (United States)
  6. Intel Corp., Hillsboro, OR (United States); Micro Encoder, Inc., Kirkland, WA (United States)
  7. Argonne National Lab. (ANL), Argonne, IL (United States); Northwestern Univ., Evanston, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Institutes of Health (NIH)
OSTI Identifier:
1371746
Alternate Identifier(s):
OSTI ID: 1348283
Grant/Contract Number:  
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physical Review B
Additional Journal Information:
Journal Volume: 95; Journal Issue: 10; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Deng, Junjing, Hong, Young Pyo, Chen, Si, Nashed, Youssef S. G., Peterka, Tom, Levi, Anthony J. F., Damoulakis, John, Saha, Sayan, Eiles, Travis, and Jacobsen, Chris. Nanoscale x-ray imaging of circuit features without wafer etching. United States: N. p., 2017. Web. doi:10.1103/PhysRevB.95.104111.
Deng, Junjing, Hong, Young Pyo, Chen, Si, Nashed, Youssef S. G., Peterka, Tom, Levi, Anthony J. F., Damoulakis, John, Saha, Sayan, Eiles, Travis, & Jacobsen, Chris. Nanoscale x-ray imaging of circuit features without wafer etching. United States. doi:10.1103/PhysRevB.95.104111.
Deng, Junjing, Hong, Young Pyo, Chen, Si, Nashed, Youssef S. G., Peterka, Tom, Levi, Anthony J. F., Damoulakis, John, Saha, Sayan, Eiles, Travis, and Jacobsen, Chris. Fri . "Nanoscale x-ray imaging of circuit features without wafer etching". United States. doi:10.1103/PhysRevB.95.104111. https://www.osti.gov/servlets/purl/1371746.
@article{osti_1371746,
title = {Nanoscale x-ray imaging of circuit features without wafer etching},
author = {Deng, Junjing and Hong, Young Pyo and Chen, Si and Nashed, Youssef S. G. and Peterka, Tom and Levi, Anthony J. F. and Damoulakis, John and Saha, Sayan and Eiles, Travis and Jacobsen, Chris},
abstractNote = {Modern integrated circuits (ICs) employ a myriad of materials organized at nanoscale dimensions, and certain critical tolerances must be met for them to function. To understand departures from intended functionality, it is essential to examine ICs as manufactured so as to adjust design rules ideally in a nondestructive way so that imaged structures can be correlated with electrical performance. Electron microscopes can do this on thin regions or on exposed surfaces, but the required processing alters or even destroys functionality. Microscopy with multi-keV x-rays provides an alternative approach with greater penetration, but the spatial resolution of x-ray imaging lenses has not allowed one to see the required detail in the latest generation of ICs. X-ray ptychography provides a way to obtain images of ICs without lens-imposed resolution limits with past work delivering 20–40-nm resolution on thinned ICs. We describe a simple model for estimating the required exposure and use it to estimate the future potential for this technique. Here we show that this approach can be used to image circuit detail through an unprocessed 300-μm-thick silicon wafer with sub-20-nm detail clearly resolved after mechanical polishing to 240-μm thickness was used to eliminate image contrast caused by Si wafer surface scratches. Here, by using continuous x-ray scanning, massively parallel computation, and a new generation of synchrotron light sources, this should enable entire nonetched ICs to be imaged to 10-nm resolution or better while maintaining their ability to function in electrical tests.},
doi = {10.1103/PhysRevB.95.104111},
journal = {Physical Review B},
number = 10,
volume = 95,
place = {United States},
year = {Fri Mar 24 00:00:00 EDT 2017},
month = {Fri Mar 24 00:00:00 EDT 2017}
}

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Works referenced in this record:

X-Ray Interactions: Photoabsorption, Scattering, Transmission, and Reflection at E = 50-30,000 eV, Z = 1-92
journal, July 1993

  • Henke, B. L.; Gullikson, E. M.; Davis, J. C.
  • Atomic Data and Nuclear Data Tables, Vol. 54, Issue 2, p. 181-342
  • DOI: 10.1006/adnd.1993.1013