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Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating

We present a method to produce small pitch gratings for X-ray interferometric imaging applications, allowing the phase sensitivity to be increased and/or the length of the laboratory setup to be minimized. The method is based on fabrication of high aspect ratio silicon microstructures using deep rea...

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Autores principales: Jefimovs, Konstantins, Vila-Comamala, Joan, Arboleda, Carolina, Wang, Zhentian, Romano, Lucia, Shi, Zhitian, Kagias, Matias, Stampanoni, Marco
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8147938/
https://www.ncbi.nlm.nih.gov/pubmed/34066906
http://dx.doi.org/10.3390/mi12050517
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author Jefimovs, Konstantins
Vila-Comamala, Joan
Arboleda, Carolina
Wang, Zhentian
Romano, Lucia
Shi, Zhitian
Kagias, Matias
Stampanoni, Marco
author_facet Jefimovs, Konstantins
Vila-Comamala, Joan
Arboleda, Carolina
Wang, Zhentian
Romano, Lucia
Shi, Zhitian
Kagias, Matias
Stampanoni, Marco
author_sort Jefimovs, Konstantins
collection PubMed
description We present a method to produce small pitch gratings for X-ray interferometric imaging applications, allowing the phase sensitivity to be increased and/or the length of the laboratory setup to be minimized. The method is based on fabrication of high aspect ratio silicon microstructures using deep reactive ion etching (Bosch technique) of dense grating arrays and followed by conformal electroplating of Au. We demonstrated that low resistivity Si substrates (<0.01 Ohm·cm) enable the metal seeding layer deposition step to be avoided, which is normally required to initiate the electroplating process. Etching conditions were optimized to realize Si recess structures with a slight bottom tapering, which ensured the void-free Au filling of the trenches. Vapor HF was used to remove the native oxide layer from the Si grating surface prior to electroplating in the cyanide-based Au electrolyte. Fabrication of Au gratings with pitch in the range 1.2–3.0 µm was successfully realized. A substantial improved aspect ratio of 45:1 for a pitch size of 1.2 µm was achieved with respect to the prior art on 4-inch wafer-based technology. The fabricated Au gratings were tested with X-ray interferometers in Talbot–Laue configuration with measured visibility of 13% at an X-ray design energy of 26 keV.
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spelling pubmed-81479382021-05-26 Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating Jefimovs, Konstantins Vila-Comamala, Joan Arboleda, Carolina Wang, Zhentian Romano, Lucia Shi, Zhitian Kagias, Matias Stampanoni, Marco Micromachines (Basel) Article We present a method to produce small pitch gratings for X-ray interferometric imaging applications, allowing the phase sensitivity to be increased and/or the length of the laboratory setup to be minimized. The method is based on fabrication of high aspect ratio silicon microstructures using deep reactive ion etching (Bosch technique) of dense grating arrays and followed by conformal electroplating of Au. We demonstrated that low resistivity Si substrates (<0.01 Ohm·cm) enable the metal seeding layer deposition step to be avoided, which is normally required to initiate the electroplating process. Etching conditions were optimized to realize Si recess structures with a slight bottom tapering, which ensured the void-free Au filling of the trenches. Vapor HF was used to remove the native oxide layer from the Si grating surface prior to electroplating in the cyanide-based Au electrolyte. Fabrication of Au gratings with pitch in the range 1.2–3.0 µm was successfully realized. A substantial improved aspect ratio of 45:1 for a pitch size of 1.2 µm was achieved with respect to the prior art on 4-inch wafer-based technology. The fabricated Au gratings were tested with X-ray interferometers in Talbot–Laue configuration with measured visibility of 13% at an X-ray design energy of 26 keV. MDPI 2021-05-07 /pmc/articles/PMC8147938/ /pubmed/34066906 http://dx.doi.org/10.3390/mi12050517 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Jefimovs, Konstantins
Vila-Comamala, Joan
Arboleda, Carolina
Wang, Zhentian
Romano, Lucia
Shi, Zhitian
Kagias, Matias
Stampanoni, Marco
Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
title Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
title_full Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
title_fullStr Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
title_full_unstemmed Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
title_short Fabrication of X-ray Gratings for Interferometric Imaging by Conformal Seedless Gold Electroplating
title_sort fabrication of x-ray gratings for interferometric imaging by conformal seedless gold electroplating
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8147938/
https://www.ncbi.nlm.nih.gov/pubmed/34066906
http://dx.doi.org/10.3390/mi12050517
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