Chemistry for electron-induced nanofabrication

Swiderek, Petra; Marbach, Hubertus; Hagen, C. W.

doi:10.3762/bjnano.9.124

Cited by 9 publications

(11 citation statements)

References 31 publications

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“…Focused electron beam induced deposition (FEBID) is a direct-write technique to fabricate nanostructures by decomposing suitable precursor molecules under the well-focused high-energy electron beam of an electron microscope. − For FEBID of metallic structures, organometallic precursors are employed. These must fulfill several requirements, the most important being (i) sufficient volatility to allow dosing of the precursor via the gas phase and (ii) low stability under electron exposure to enable complete removal of the organic components of the precursor.…”

Section: Introductionmentioning

confidence: 99%

Water-Assisted Process for Purification of Ruthenium Nanomaterial Fabricated by Electron Beam Induced Deposition

Rohdenburg

Winkler

Kuhness

et al. 2020

ACS Appl. Nano Mater.

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The purity of nanomaterials fabricated by focused electron beam induced deposition (FEBID) is often not high enough for the desired application. For instance, large amounts of carbon incorporated into the deposits deteriorate their electrical conductivity. Such impurities stem from incomplete electron-induced fragmentation of the applied precursors. Except for nanomaterials containing the most noble and thus oxidation-resistant metals, deposits cannot be purified by harsh post-processing steps like O 2 treatment, and excessive thermal annealing is detrimental to the desired shape fidelity. Milder purification protocols based on electron irradiation in the presence of H 2 O vapor have thus been developed, and it was demonstrated that they yield pure Pt and Au deposits. Herein, we report on the application of such a water-assisted purification strategy to deposits produced from the FEBID precursor bis(ethylcyclopentadienyl)ruthenium(II) ((EtCp) 2 Ru). Such Ru nanomaterials are relevant to the repair of masks for extreme ultraviolet lithography. In contrast to noble metals, where higher doses lead to higher purity, and contrary to purification using O 2 that is accompanied by a continuous increase of the oxygen content, we here demonstrate the existence of an ideal purification dose for Ru-based FEBID materials, where oxidation is kept at a minimum, while carbon is effectively removed from the deposits. In addition, a complementary surface study under ultrahigh vacuum conditions provides insights into the chemistry that transforms the carbonaceous contamination into CO. The results provide evidence that water-assisted purification can be applied to a wider range of FEBID deposits also including those containing Ru as an example of a less noble metal.

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Section: Introductionmentioning

confidence: 99%

Water-Assisted Process for Purification of Ruthenium Nanomaterial Fabricated by Electron Beam Induced Deposition

Rohdenburg

Winkler

Kuhness

et al. 2020

ACS Appl. Nano Mater.

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“…The situation is different for beam-assisted deposition techniques where precursor molecules (often metal-containing) are introduced to the vicinity of a substrate by a gas-injection system. Although the possible role of secondary electrons in the deposition process has recently inspired a large number of studies on low-energy electron interactions with deposition precursors, there are practically no data concerning the interaction of these precursors with primary ions. The spread of secondary electrons interacting with precursor molecules during the focused ion beam-induced deposition (FIBID) is low, increasing the relative importance of precursor decomposition by primary ions, as studied in the present work.…”

Section: Introductionmentioning

confidence: 99%

Decomposition of Iron Pentacarbonyl Induced by Singly and Multiply Charged Ions and Implications for Focused Ion Beam-Induced Deposition

et al. 2019

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Focused ion beams are becoming important tools in nanofabrication. The underlying physical processes in the substrate were already explored for several projectile ions. However, studies of ion interaction with precursor molecules for beam-assisted deposition are almost nonexistent. Here, we explore the interaction of various projectile ions with iron pentacarbonyl. We report fragmentation patterns of isolated gas-phase iron pentacarbonyl after interaction with 4He+ at a collision energy of 16 keV, 4He2+ at 16 keV, 20Ne+ at 6 keV, 20Ne4+ at 40 keV, 40Ar+ at 3 keV, 40Ar3+ at 21 keV, 84Kr3+ at 12 keV, and 84Kr17+ at 255 keV. These projectiles cover interaction regimes ranging from collisions dominated by nuclear stopping through collisions dominated by electronic stopping to soft resonant electron-capture interactions. We report a surprising efficiency of Ne+ in the Fe(CO)5 decomposition. The interaction with multiply charged ions results in a higher content of parent ions and slow metastable fragmentation due to the electron-capture process. The release of CO groups during the decomposition process seems to take off a significant amount of energy. The fragmentation mechanism may be described as Fe being trapped within a CO cluster.

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“…However, the underlying physics and chemistry of the repair process is considerably complex. On a fundamental level, we identify three main contributions: the size of the electron affected area of the mask, [22][23][24][25][26] the properties of the precursor molecules in general 20 and particularly the mask material, 22,23,25 and finally the instrumental setup. Furthermore, each of the listed contributors can be broken down in several subtopics all influencing the achievable resolution.…”

Section: Epe and Minimum Repair Size-what Is Limiting Resolutionmentioning

confidence: 99%

“…[16][17][18][19] The basic principle of FEBIP is the very local alteration of adsorbed precursor molecules or/and the substrate by the impact of electrons. 17,20 More specifically, focused electron-beam induced etching (FEBIE) 15,16 is used as a subtractive and focused electron-beam induced deposition (FEBID) 18,19,21 as an additive technique. To do so, the focused e-beam is applied in the presence of certain precursor molecules thus triggering the local removal (FEBIE) or deposition (FEBID) of material.…”

Section: Introductionmentioning

confidence: 99%

Pushing the limits of EUV mask repair: addressing sub-10 nm defects with the next generation e-beam-based mask repair tool

Heil

Waldow

Capelli

et al. 2021

J. Micro/Nanopattern. Mats. Metro.

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Mask repair is an essential step in the manufacturing process of extreme ultraviolet (EUV) masks. Its key challenge is to continuously improve resolution and control to enable the repair of the ever-shrinking feature sizes on mask along the EUV roadmap. The state-of-the-art mask repair method is gas-assisted electron-beam (e-beam) lithography also referred to as focused electron-beam induced processing (FEBIP). We discuss the principles of the FEBIP repair process, along with the criteria to evaluate the repairs, and identify the major contributions determining the achievable resolution. As key results, we present several high-end repairs on EUV masks including a sub-10-nm extrusion achieved with the latest generation of e-beambased mask repair tools, the MeRiT ® LE. Furthermore, we demonstrate the corresponding repair verification using at-wavelength (actinic) measurements. © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Chemistry for electron-induced nanofabrication

Cited by 9 publications

References 31 publications

Water-Assisted Process for Purification of Ruthenium Nanomaterial Fabricated by Electron Beam Induced Deposition

Water-Assisted Process for Purification of Ruthenium Nanomaterial Fabricated by Electron Beam Induced Deposition

Decomposition of Iron Pentacarbonyl Induced by Singly and Multiply Charged Ions and Implications for Focused Ion Beam-Induced Deposition

Pushing the limits of EUV mask repair: addressing sub-10 nm defects with the next generation e-beam-based mask repair tool

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