Hydrolytic Stability and Hydrogen Peroxide Activation of Zirconium‐Based Oxoclusters

Faccioli, Francesco; Pedron, Danilo; Sorarù, Antonio; Carraro, Mauro; Gross, Silvia

doi:10.1002/ejic.201402767

Cited by 47 publications

(54 citation statements)

References 110 publications

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“…we observed that upon film deposition this material seems to lose the extra carboxylic acid molecules that are not covalently bonded to the inorganic core but that are occluded in the crystalline sample. [24] Their presence in the crystalline powder sample can be detected by a weight loss around 200 o C in the TGA, and in the IR spectrum ( Fig. 1a-b, C=O stretching at 1697 cm -1 and broad band between 2770 and 3515 cm -1 due to O-H stretching of the carboxylic acid, marked with asterisk).…”

Section: Lithographic Performancementioning

confidence: 95%

“…It is known that carboxylate ligands in oxoclusters can be displaced by water or by competing chelating agents. [24] XPS analyses shown below point in this direction and thus optimisation of spin-coating and sample handling is required for this molecular material. The trends in sensitivity were also observed in dense line pattern transfer ( Table 1).…”

Section: Lithographic Performancementioning

confidence: 99%

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Ti, Zr, and Hf-based molecular hybrid materials as EUV photoresists

Castellanos¹,

Wu²,

Baljozović³

et al. 2018

Extreme Ultraviolet (EUV) Lithography IX

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Metal oxoclusters are hybrid inorganic-organic molecular compounds with a well-defined number of metal and oxygen atoms in their cores. This type of materials is a promising platform for extreme ultraviolet (EUV) photoresists: their inorganic cores provide them with tunable EUV absorptivity and their molecular nature might favour smaller resolution and roughness while it also renders specific spectroscopic fingerprints that allow to monitor the chemical changes induced by EUV light. In this work, we compare the EUV photochemistry of metal oxoclusters based on Ti, Zr, and Hf and methacrylate ligands (Mc) and their sensitivity as resist materials for EUV lithography. Decarboxylation processes upon EUV exposure are detected in all cases with ex-situ X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR). However, the structural changes after film deposition and after exposure differed among the three compounds. Higher sensitivity was detected for the Hf-based material than for the Zr-based analogue, in line with its higher absorptivity. XPS analyses suggest that only a small fraction of the carboxylate ligands is lost at the dose-to-gel. This change in the chemical composition is accompanied by an increased structural disorder in the layer and a rather small degree of aggregation, according to grazing incidence X-ray scattering (GIXS). These results indicate that neither a drastic loss of organic shell nor a high degree of aggregation of the naked inorganic cores are required for this type of molecular thin film to reliably operate as a resist material.

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Section: Lithographic Performancementioning

confidence: 95%

Section: Lithographic Performancementioning

confidence: 99%

Ti, Zr, and Hf-based molecular hybrid materials as EUV photoresists

Castellanos¹,

Wu²,

Baljozović³

et al. 2018

Extreme Ultraviolet (EUV) Lithography IX

View full text Add to dashboard Cite

show abstract

“…Originally, those carboxylic acids are not covalently bonded to the inorganic core but are occluded in the crystalline sample. 28 Their presence in the crystalline powder sample can be detected and in the IR spectrum [Figs. 1(a) and 1(b), C═O stretching at 1697 cm −1 and broadband between 2770 and 3515 cm −1 due to O─H stretching of the carboxylic acid, marked with asterisk] and it is further supported by the mass ratio between combustible organics and incombustible inorganic residue found in the TGA.…”

Section: Lithographic Performancementioning

confidence: 99%

Mechanistic insights in Zr- and Hf-based molecular hybrid EUV photoresists

Baljozović

Portale

et al. 2019

J. Micro/Nanolith. MEMS MOEMS

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Background: Inorganic resists show promising performances in extreme ultraviolet (EUV) lithography. Yet, there is a need for understanding the exact chemical mechanisms induced by EUV light on these materials. Aim: To gain knowledge on the EUV chemistry of inorganic resists, we investigate hybrid inorganic-organic molecular compounds, metal oxoclusters (MOCs). Their molecular nature allows for the monitoring of specific structural changes by means of spectroscopy and thus for the elucidation of the mechanisms behind pattern formation. Approach: We compare the sensitivity of MOCs based on Zr and Hf, and methacrylate ligands as EUV resists. The chemical and structural changes causing the solubility switch were investigated by ex situ x-ray spectroscopy, infrared spectroscopy, ultraviolet-visible spectroscopy, and grazing incidence x-ray scattering. Results: Higher sensitivity was detected for the Hf-based material, in line with its higher absorptivity. A small fraction of the carboxylate ligands is lost at doses that yield solubility contrast, whereas aggregation of the inorganic clusters was not observed. Conclusions: These results provide evidence that, although the mechanism of solubility switch in these materials starts with decarboxylation reactions, it mainly proceeds through cross linking of the organic shells instead of aggregation of the inorganic clusters.

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“…Between these, PSE is believed to be a simple way to introduce unsaturated open sites while preserving the MOFs’ structural integrity and high porosity . In addition, it has been found that the formation of Zr IV ‐peroxo complexes by reaction of the Zr‐oxoclusters [Zr 6 O 4 (OH) 4 ] with oxidizing agents contributes to the sulfur oxidation in ODS, suggesting that a larger number of Zr IV sites can bring enhanced catalytic activity . UiO‐66, with its 12‐fold, fully connected hexanuclear Zr clusters, has been studied for ODS by Granadeiro et al, showing outstanding efficiency .…”

Section: Introductionmentioning

confidence: 99%

Zr‐Metal‐Organic Framework Catalysts for Oxidative Desulfurization and Their Improvement by Postsynthetic Ligand Exchange

Bueken

Vos

2018

Small Methods

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Two types of Zr6‐based metal‐organic frameworks (MOF), {Zr6O4(OH)4(C6H3(COO)3)2(HCOO)6} (MOF‐808) and {Zr6O4(OH)4(C24H15(COO)3)2(HCOO)6} (UMCM‐309) are investigated as heterogeneous catalysts in oxidative desulfurization reactions. Postsynthetic approaches targeting the removal of the coordinating formate ligands are applied to further improve the MOFs’ catalytic activity, resulting in the formation of additional ZrIV open sites. Thus, three modified MOFs, namely MOF‐808‐M, UMCM‐309‐M1, and UMCM‐309‐M2, are synthesized with larger numbers of open sites, as shown by CD3CN chemisorption monitored by Fourier‐transform infrared spectroscopy (FTIR), leading to higher catalytic activity. Even at low catalyst loading, MOF‐808‐M exhibits high catalytic activity in the oxidation of sulfur compounds as well as high selectivity and reusability.

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Hydrolytic Stability and Hydrogen Peroxide Activation of Zirconium‐Based Oxoclusters

Cited by 47 publications

References 110 publications

Ti, Zr, and Hf-based molecular hybrid materials as EUV photoresists

Ti, Zr, and Hf-based molecular hybrid materials as EUV photoresists

Mechanistic insights in Zr- and Hf-based molecular hybrid EUV photoresists

Zr‐Metal‐Organic Framework Catalysts for Oxidative Desulfurization and Their Improvement by Postsynthetic Ligand Exchange

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