Mixed-ligand zinc-oxoclusters: efficient chemistry for high resolution nanolithography

Thakur, Neha; Bliem, Roland; Mochi, Iacopo; Vockenhuber, Michaela; Ekinci, Yasin; Castellanos, Sonia

doi:10.1039/d0tc03597a

Cited by 26 publications

(58 citation statements)

References 62 publications

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“…Note that C–F bond dissociation is required for formation of a volatile product that fragments to H 2 CF + when entering the QMS. C–F bond cleavage was also observed when Zn(MA)(TFA) was exposed to EUV radiation, 25 supporting the present interpretation. Products such as CHF 3 and CH 2 F 2 are conceivable as origin of the signals at m / z 51 and m / z 33.…”

Section: Resultssupporting

confidence: 90%

“…The present results complement the recent EUV irradiation study of Zn(MA)(TFA) resist samples 25 by revealing that a typical photoelectron released upon absorption of an EUV photon, represented here by electron irradiation at an energy of 80 eV, induces similar chemical changes in the sample as the actual photoabsorption and consequent ionization. The effect at 20 eV, i.e., for electrons with an energy in the upper part of the range characteristic of LESEs, is somewhat weaker but still remarkable.…”

Section: Comparison With Euv Resultssupporting

confidence: 83%

“…These latter signals are significantly more intense than expected from the fragmentation pattern of CO 2 measured previously. 30 This indicates that the carboxylate group is not exclusively lost as CO 2 under electron exposure as observed in the case of copper carboxylates 26,30 but fragments further, probably driven by the formation of Zn oxide 25 that was also observed upon electron irradiation in other Zn carboxylates. 31 …”

Section: Resultsmentioning

confidence: 63%

“…This is in line with a mechanism proposed recently according to which the radical species initiate crosslinking reactions. 25 The results so far represent the effect of 80 eV photoelectrons as emitted in the resist layer upon absorption of EUV photons. Such photoelectrons can promote further ionization events and thus generate LESEs that might also contribute to the reactions occurring in the resist.…”

Section: Electron-stimulated Desorption From Zn(ma)(tfa) and Zn(tfa) Resist Layersmentioning

confidence: 99%

“…1) have been brought forward recently. 24,25 In this type of resist, the solubility switch observed upon EUV irradiation has been explained as an effect of crosslinking of the MA ligands and a low degree of decarboxylation. While the role of electron-induced chemistry has not yet been explored in Zn(TFA)(MA) oxoclusters, a previous study on several Cu carboxylate complexes has revealed that the degradation of the latter materials under electron irradiation is in fact dominated by expulsion of CO 2 .…”

Section: Introductionmentioning

confidence: 99%

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Role of low-energy electrons in the solubility switch of Zn-based oxocluster photoresist for extreme ultraviolet lithography

Rohdenburg

Thakur

Cartaya

et al. 2021

Phys. Chem. Chem. Phys.

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Section: Resultssupporting

confidence: 90%

Section: Comparison With Euv Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 63%

Section: Electron-stimulated Desorption From Zn(ma)(tfa) and Zn(tfa) Resist Layersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Role of low-energy electrons in the solubility switch of Zn-based oxocluster photoresist for extreme ultraviolet lithography

Rohdenburg

Thakur

Cartaya

et al. 2021

Phys. Chem. Chem. Phys.

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Structural investigation of zinc‐based photoresists with different substituents for high‐resolution lithography

Luo

Liu

et al. 2023

Applied Organom Chemis

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The fineness of the photolithographic pattern depends largely on the composition and structure of the photoresist, and different structures endow metal‐based photoresists with different photon‐absorbing capabilities. Here, we synthesized zinc‐based photoresists with different electron‐effect substituents (amine and bromine) in the ligands and investigated the influence of the ligand groups on the sensitivity and resolution at deep ultraviolet and electron beam. The developed resist patterns exhibit that the sensitivity of the Zn‐based photoresists containing bromine groups (Zn‐PBBA) is nearly seven times higher than the Zn‐based photoresists containing amine groups (Zn‐PABA) at the same resolution under ultraviolet irradiation, which is supported by the density functional theory (DFT) calculations where a smaller HOMO–LUMO gap for Zn‐PBBA is obtained. Analogously, the Zn‐PBBA also showed better sensitivity and resolution than Zn‐PABA at EBL, with a resolution of 70 nm at a dose of 800 mJ cm−2 by characterization with AFM. This work provides an understanding of the efficient structural design of photoresists and future guidance for the development of better‐performing materials.

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Absorption‐coefficient calculation of short‐wavelength photoresist materials: From EUV to BEUV and water window X‐ray

Peng,

Chen,

Chen

et al. 2024

Smart Molecules

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In photolithography, shortening the exposure wavelength from ultraviolet to extreme ultraviolet (EUV, 13.5 nm) and soft X‐ray region in terms of beyond EUV (BEUV, 6.X nm) and water window X‐ray (WWX, 2.2–4.4 nm) is expected to further miniaturize the technology node down to sub‐5 nm level. However, the absorption ability of molecules in these ranges, especially WWX region, is unknown, which should be very important for the utilization of energy. Herein, the molar absorption cross sections of different elements at 2.4 nm of WWX were firstly calculated and compared with the wavelengths of 13.5 nm and 6.7 nm. Based on the absorption cross sections in these ranges and density estimation results from the density‐functional theory calculation, the linear absorption coefficients of typical resist materials, including metal‐oxy clusters, organic small molecules, polymers, and photoacid generators (PAGs), are evaluated. The analysis suggests that the Zn cluster has higher absorption in BEUV, whereas the Sn cluster has higher absorption in WWX. Doping PAGs with high EUV absorption atoms improves chemically amplified photoresist (CAR) polymer absorption performance. However, for WWX, it is necessary to introduce an absorption layer containing high WWX absorption elements such as Zr, Sn, and Hf to increase the WWX absorption.

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Mixed-ligand zinc-oxoclusters: efficient chemistry for high resolution nanolithography

Abstract: The combined reactivity of methacrylate and trifluoroacetate ligands make zinc-oxoclusters pattern 22–50 nm lines with high sensitivity by EUV Lithography.

Cited by 26 publications

References 62 publications

Role of low-energy electrons in the solubility switch of Zn-based oxocluster photoresist for extreme ultraviolet lithography

Role of low-energy electrons in the solubility switch of Zn-based oxocluster photoresist for extreme ultraviolet lithography

Structural investigation of zinc‐based photoresists with different substituents for high‐resolution lithography

Absorption‐coefficient calculation of short‐wavelength photoresist materials: From EUV to BEUV and water window X‐ray

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