J. Eur. Opt. Society-Rapid Publ. 2025, 21, 7 Ó The Author( s), published by EDP Sciences, 2025 https:// doi. org / 10.1051 / jeos / 2025002 Available online at: https:// jeos. edpsciences. org
Journal of the European Optical Society-Rapid Publications
EOSAM 2024 Guest editors: Luca De Stefano and Raffaele Velotta
RESEARCH ARTICLE
Resolution enhancement methods in optical microscopy for dimensional optical metrology
Mohammad Nouri 1, 2, Paolo Olivero 3, Stefanie Kroker 1, 2, Tim Käseberg 2, Ivano Ruo-Berchera 4, Bernd Bodermann 2,*
, Himanshu Tyagi 5, Deb Roy 5, Deshabrato Mukherjee 6, Thomas Siefke 7, Poul Erik Hansen 8, Astrid Tranum Rømer 8, Miroslav Valtr 9, Pietro Aprà 10, and Peter Petrik 6, 11
1 |
Institut für Halbleitertechnik, Laboratory for Emerging Nanometrology, Technische Universität Braunschweig, |
Hans-Sommer-Str. 66, 38106 Braunschweig, Germany |
2 |
Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany |
3 |
Physics Department, University of Torino, via P. Giuria 1, 10125 Torino, Italy |
4 |
Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy |
5 |
Swansea University, Singleton Park, Swansea SA28PP, Wales, UK |
6 |
Institute of Technical Physics and Materials Science, Konkoly Thege Str. 29-33, Budapest, 1121, Hungary |
7 |
Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University Jena, Albert-Einstein-Strasse 15, Jena, 07745, |
Germany |
8 |
DFM, Danish National Metrology Institute, Kogle Allé 5, 2970 Hørsholm, Denmark |
9 |
Czech Metrology Institute, Okružní 31, 638 00 Brno, Czech Republic |
10 |
National Institute of Nuclear Physics( INFN), Torino Section, via Pietro Giuria, 10125 Torino, Italy |
11 |
Department of Electrical Engineering, Institute of Physics, Faculty of Science and Technology, University of Debrecen, |
Bem ter 18, Debrecen, 4026, Hungary |
Received 30 August 2024 / Accepted 7 January 2025
Abstract. In this paper, we discuss several enhancement approaches to increase the resolution and sensitivity of optical microscopy as a tool for dimensional nanometrology. Firstly, we discuss a newly developed throughfocus microscopy technique providing additional phase information from the afocal images to increase the nanoscale sensitivity of classical microscopy. We also explore different routes to label-free or semiconductor compatible labelling super-resolution microscopy suitable for a broad range of technical applications. We present initial results from, a new wide-field super-resolution imaging technique enabled by Raman scattering. In addition, we discuss super-resolution imaging using NV centres in nano-diamonds as labels and their application in future reference standards.
Keywords: Nitrogen-vacancy( NV) centres, STED microscopy, Photoluminescence, Label-free super-resolution, Optical nanometrology, Through-focus microscopy, Non-linear Raman super-resolution.
1 Introduction: A path to universal imaging nanometrology
Complex micro- and nano-scale structures of different materials are the basis of the development and fabrication of modern and future electronic and optical devices. Typically, the functionalities of these devices crucially depend on the size e. g. the line width or critical dimension and other shape details of the structures. Therefore, accurate, reliable, and efficient dimensional metrology is mandatory both for development and manufacturing process and quality control. Although sophisticated nanoscale
* Corresponding author: bernd. bodermann @ ptb. de metrology methods based on charged particles( such as scanning electron microscopy SEM, transmission electron microscopy TEM, Helium ion microscopy HIM or scanning tunnelling microscopy STM), X-Rays( transmission( TSAX) or grazing incidence( GISAX) small angle X-ray scattering) or tactile probes( e. g. Atomic Force Microscopy AFM) are available( cf. for example [ 1 ] and references therein), optical methods such as optical microscopy and scatterometry are advantageous due to their nondestructive nature, high speed and good in-line capability [ 2 ].
Achieving reliable and precise measurements for analysing these structures is a challenge for various fields of science and industry. Non-imaging optical methods like scatterometry or ellipsometry, in semiconductor metrology
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