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 23 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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Theoretical Insights into the Solubility Polarity Switch of Metal–Organic Nanoclusters for Nanoscale Patterning

et al. 2023

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Metal–organic nanoclusters(MOCs) are being increasingly used as prospective photoresist candidates for advanced nanoscale lithography technologies. However, insight into the irradiation‐induced solubility switching process remains unclear. Hereby, the theoretical study employing density functional theory (DFT) calculations of the alkene‐containing zirconium oxide MOC photoresists is reported, which is rationally synthesized accordingly, to disclose the mechanism of the nanoscale patterning driven by the switch of solubility from the acid‐catalyzed or electron‐triggered ligand dissociation. By evaluating the dependence of MOCs’ imaging process on photoacid, lithographies of photoresists with and without photoacid generators after exposure to ultraviolet (UV), electron beam, and soft X‐ray, it is revealed that photoacid is essential in UV lithography, but it demonstrates little effect on exposure dose in high‐energy lithography. Furthermore, theoretical studies using DFT simulations to investigate the plausible photoacid‐catalyzed, electron‐triggered dissociation, and accompanying radical reaction are performed, and a mechanism is demonstrated that the nanoscale patterning of this type of MOCs is driven by the solubility switch resulting from dissociation‐induced strong electrostatic interaction and low‐energy barrier radical polymerization with other species. This study can give insights into the chemical mechanisms of patterning, and guide the rational design of photoresists to realize high resolution and high sensitivity.

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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 23 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

Theoretical Insights into the Solubility Polarity Switch of Metal–Organic Nanoclusters for Nanoscale Patterning

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