Unravelling the effect of fluorinated ligands in hybrid EUV photoresists by X-ray spectroscopy

Wu, Lianjia; Bespalov, Ivan; Witte, Katharina; Lugier, Olivier; Haitjema, Jarich; Vockenhuber, Michaela; Ekinci, Yasin; Watts, Benjamin; Brouwer, Albert M.; Castellanos, Sonia

doi:10.1039/d0tc03216f

Cited by 32 publications

(32 citation statements)

References 56 publications

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“…Based on these results, the Zr oxo cluster film possesses significantly greater sensitivity than the Zr6O4 cluster film. We note that the sensitivity of the Zr6O4 cluster agrees with previous reports [3b,4d] . Meanwhile, the sensitivity of the Zr oxo cluster is equally good or even better, compared to other reported photoresists [3b,4d,23b] …”

Section: Resultssupporting

confidence: 91%

“…As photoresists, the films of Zr6O4 clusters can be patterned in the presence or absence of photoacid generators (PAG) at EUV dose ranging from 50 to 100 mJ/cm 2 . Indeed, the sensitivity of the Zr6O4 film is considerably lower than that of ZrO 2 nanoparticles [4d,12a,15] . To obtain higher resolution, it is necessary to transcend the trade‐off relationship among resolution, line‐width‐roughness, and sensitivity [16] .…”

Section: Introductionmentioning

confidence: 99%

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Enhanced Solubility of Zirconium Oxo Clusters from Diacetoxyzirconium(IV) Oxide Aqueous Solution as Inorganic Extreme‐Ultraviolet Photoresists

Kataoka

Sue

2022

Eur J Inorg Chem

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Metal oxo clusters have drawn a great deal of attention as the extreme‐ultraviolet (EUV) photoresists. However, industrial implementation in the next‐generation lithography demands further improvements in their sensitivity and resolution. In this study, a zirconium oxo cluster with methacrylate and acetate ligands was synthesized from diacetoxyzirconium(IV) oxide aqueous solution for use as EUV photoresist materials. The obtained Zr oxo cluster, consisting of a Zr core and methacrylate and acetate ligands, was similar in size to Zr6O4(OH)4(methacrylate)12 cluster, but much more soluble in a variety of organic solvents. Open‐frame exposure tests revealed that the Zr oxo cluster served as a negative tone photoresist with a sensitivity greater than that of Zr6O4(OH)4(methacrylate)12 cluster. At a dose of 22 mJ/cm2 in the absence of photoacid generators, the Zr oxo cluster film resolved a pattern 15 nm in width, which is sufficiently low to meet the current technological requirements.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Enhanced Solubility of Zirconium Oxo Clusters from Diacetoxyzirconium(IV) Oxide Aqueous Solution as Inorganic Extreme‐Ultraviolet Photoresists

Kataoka

Sue

2022

Eur J Inorg Chem

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“…Previous studies have shown that introduction of a – CF 3 group at the α position decreases the rate of radical homopolymerization of the TFMA unit. , Different molecular packing of the oxoclusters in Zn(TFMA) compared to its analogue Zn(MA)(TFA) or a reduced ratio of the solubility rates of the unexposed and exposed regions in the developer of choice can also contribute toward this observed decrease in the sensitivity. Therefore, incorporation of more fluorine does not always directly translate into better EUVL performance of the photoresist, in contrast to the previous reported studies. , Further, contrast curve studies demonstrated that postexposure bake (PEB) applied at 120 °C/30 s under ambient conditions led to a further slight decrease in the sensitivity (also see section ). Spectroscopic studies to identify the chemical changes induced by PEB in the oxocluster were also carried out, and are discussed in section .…”

Section: Resultsmentioning

confidence: 65%

“…Therefore, incorporation of more fluorine does not always directly translate into better EUVL performance of the photoresist, in contrast to the previous reported studies. 23,40 Further, contrast curve studies demonstrated that postexposure bake (PEB) applied at 120 °C/30 s under ambient conditions led to a further slight decrease in the sensitivity (also see section 3.4). Spectroscopic studies to identify the chemical changes induced by PEB in the oxocluster were also carried out, and are discussed in section 3.7.…”

Section: Thin Films and Euv Contrast Curvesmentioning

confidence: 93%

Fluorine-Rich Zinc Oxoclusters as Extreme Ultraviolet Photoresists: Chemical Reactions and Lithography Performance

et al. 2022

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The absorption of extreme ultraviolet (EUV) radiation by a photoresist strongly depends on its atomic composition. Consequently, elements with a high EUV absorption cross section can assist in meeting the demand for higher photon absorbance by the photoresist to improve the sensitivity and reduce the photon shot noise induced roughness. In this work, we enhanced the EUV absorption of the methacrylic acid ligands of Zn oxoclusters by introducing fluorine atoms. We evaluated the lithography performance of this fluorine-rich material as a negative tone EUV photoresist along with extensive spectroscopic and microscopic studies, providing deep insights into the underlying mechanism. UV−vis spectroscopy studies demonstrate that the presence of fluorine in the oxocluster enhances its stability in the thin films to the ambient atmosphere. However, the EUV photoresist sensitivity (D 50 ) of the fluorine-rich oxocluster is decreased compared to its previously studied methacrylic acid analogue. Scanning transmission X-ray microscopy and in situ X-ray photoelectron spectroscopy in combination with FTIR and UV−vis spectroscopy were used to gain insights into the chemical changes in the material responsible for the solubility switch. The results support decarboxylation of the ligands and subsequent radical-induced polymerization reactions in the thin film upon EUV irradiation. The rupture of carbon−fluorine bonds via dissociative electron attachment offers a parallel way of generating radicals. The mechanistic insights obtained here will be applicable to other hybrid materials and potentially pave the way for the development of EUV materials with better performance.

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“…The reaction scheme is similar to an earlier published reaction scheme. 62 When excited by 266 nm DUV pulses, the streak trace differs significantly from CB alone, as it is both red-shifted and decays on a longer time-scale. Fig.…”

Section: Xuv Excited Optical Luminescence a Xeol Behavior Of Sodium S...mentioning

confidence: 99%

Extreme Ultraviolet-Excited Time-Resolved Luminescence Spectroscopy Using an Ultrafast Table-Top High-Harmonic Generation Source

van der Geest,

Sadegh,

Meerwijk

et al. 2021

Preprint

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We present a table-top extreme ultraviolet (XUV) beamline for measuring time-and frequencyresolved XUV excited optical luminescence (XEOL) with additional femtosecond-resolution XUV transient absorption spectroscopy functionality. XUV pulses are generated via high-harmonic generation using a near-infrared pulse in a noble gas medium, and focused to excite luminescence from a solid sample. The luminescence is collimated and guided into a streak camera, where its spectral components are temporally resolved with picosecond temporal resolution. We time-resolve XUV excited luminescence and compare the results to luminescence decays excited at longer wavelengths for three different materials : (i) sodium salicylate, an often used XUV scintillator, (ii) fluorescent labeling molecule 4-carbazole benzoic acid (CB), and (iii) a zirconium metal oxo-cluster labeled with CB, which is a photoresist candidate for extreme-ultraviolet lithography. Our results establish time-resolved XEOL as a new technique to measure transient XUV-driven phenomena in solid-state samples, and identify decay mechanisms of molecules following XUV and soft-X-ray excitation.

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Unravelling the effect of fluorinated ligands in hybrid EUV photoresists by X-ray spectroscopy

Abstract: A fluorinated ligand in an extreme ultraviolet hybrid photoresist yields C–F bond dissociation upon exposure, thus enhancing its overall sensitivity.

Cited by 32 publications

References 56 publications

Enhanced Solubility of Zirconium Oxo Clusters from Diacetoxyzirconium(IV) Oxide Aqueous Solution as Inorganic Extreme‐Ultraviolet Photoresists

Enhanced Solubility of Zirconium Oxo Clusters from Diacetoxyzirconium(IV) Oxide Aqueous Solution as Inorganic Extreme‐Ultraviolet Photoresists

Fluorine-Rich Zinc Oxoclusters as Extreme Ultraviolet Photoresists: Chemical Reactions and Lithography Performance

Extreme Ultraviolet-Excited Time-Resolved Luminescence Spectroscopy Using an Ultrafast Table-Top High-Harmonic Generation Source

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