Very Thin Extreme Ultraviolet Mask Absorber Material for Extremely Fine Pitch Patterning

Lee, Jae Uk; Hong, Seok-Jin; Ahn, Jinho

doi:10.7567/apex.6.076502

Cited by 7 publications

(6 citation statements)

References 22 publications

(18 reference statements)

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“…As a matter of fact, the refractive index of Pd 46 is generally larger than that of PdO. 47,48 Finally, a weak signal appeared gradually at 1988 cm −1 along PdO reduction that could be assigned to ν(Pd−H). This assignment remains tentative because Pd hydrides are predominantly bridged species, and the corresponding vibrational modes appear at lower energy.…”

Section: Resultsmentioning

confidence: 99%

Reduction of PdO/Al₂O₃ in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

et al. 2021

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Supported Pd-based catalysts used in heterogeneously catalyzed liquid phase processes often undergo an activation step through reduction of the oxide phase or of the oxidic passivation layer prior to reaction. An oxidized Pd/Al2O3 catalyst was reduced by using H2-saturated cyclohexane at 70 °C, and reduction was followed in real time by attenuated total reflection infrared spectroscopy (ATR-IR), high-energy X-ray diffraction (XRD), and quick scanning X-ray absorption spectroscopy (XAS) to obtain the perspective from different materials properties. We show that dynamic Pd speciation changes can be monitored during reduction in the liquid phase. XRD and XAS indicated that the isothermal PdO reduction passes through an intermediate Pd0 phase toward the formation of a well-defined Pd hydride phase. Based on the different sensitivities of the two techniques, XRD suggested that the process ends with a dominant Pd hydride phase, while XAS revealed an equal proportion of Pd0 and Pd hydride. The time-resolved XAS data suggested that the isothermal reduction of PdO in cyclohexane to Pd0 occurs through a nucleation mechanism and that Pd0 is rapidly converted into the hydride phase according to a contracting sphere model. The identification and the presence of a mixed Pd0/PdH x phase appears crucial in view of the relevance of these species in for instance hydrogenation reactions.

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Section: Resultsmentioning

confidence: 99%

Reduction of PdO/Al₂O₃ in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

et al. 2021

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“…10 Soon after that Obert Wood et al from Lucent reported the first experimental realization of attPSM for EUV including extensive simulation studies. 11 Since then, many different forms of attPSM for EUV including etched multilayer configurations [12][13][14] and various absorber stack configurations [15][16][17] were proposed and investigated.…”

Section: Introductionmentioning

confidence: 99%

Attenuated phase shift mask for extreme ultraviolet: can they mitigate three-dimensional mask effects?

2018

J. Micro/Nanolith. MEMS MOEMS

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The understanding, characterization, and mitigation of three-dimensional (3-D) mask effects including telecentricity errors, contrast fading, and best focus shifts become increasingly important for the performance optimization of future extreme ultraviolet (EUV) projection systems and mask designs. We explore the potential of attenuated phase shift mask (attPSM) to mitigate 3-D mask effects and exploit them for future EUV imaging. The scattering of light at the absorber edges results in significant phase deformations, which impact the effective phase and the lithographic performance of attPSM for EUV. Rigorous mask and imaging simulations in combination with multiobjective optimization techniques are employed to identify the most appropriate material properties, mask, and source geometries. The resulting imaging performance is compared to the achievable performance of binary EUV masks.

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“…Alternatively, absorber materials with appropriate combinations of refractive index n and extinction k can be used to devise attenuated phase shift masks (PSM) for EUV. Both approaches have been investigated for EUV systems with an NA of 0.33, [17][18][19][20][21] including a first experimental demonstration of improved imaging performance of high k absorbers. 22 The effective thickness of EUV masks depends also on the multilayer.…”

Section: Paths Toward Mitigationmentioning

confidence: 99%

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

Erdmann

Mesilhy

Evanschitzky

et al. 2020

J. Micro/Nanolith. MEMS MOEMS

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Next-generation extreme ultraviolet (EUV) systems with numerical apertures of 0.55 have the potential to provide sub-8-nm half-pitch resolution. The increased importance of stochastic effects at smaller feature sizes places further demands on scanner and mask to provide high contrast images. We use rigorous mask diffraction and imaging simulation to understand the impact of the EUV mask absorber and to identify the most appropriate optical parameters for high NA EUV imaging. Simulations of various use cases and material options indicate two main types of solutions: high extinction materials, especially for lines spaces, and low refractive index materials that can provide phase shift mask solutions. EUV phase masks behave very different from phase shift masks for DUV. Carefully designed low refractive index materials and masks can open up a new path toward high contrast edge printing. © 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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Very Thin Extreme Ultraviolet Mask Absorber Material for Extremely Fine Pitch Patterning

Cited by 7 publications

References 22 publications

Reduction of PdO/Al₂O₃ in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

Reduction of PdO/Al₂O₃ in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

Attenuated phase shift mask for extreme ultraviolet: can they mitigate three-dimensional mask effects?

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

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Very Thin Extreme Ultraviolet Mask Absorber Material for Extremely Fine Pitch Patterning

Cited by 7 publications

References 22 publications

Reduction of PdO/Al2O3 in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

Reduction of PdO/Al2O3 in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

Attenuated phase shift mask for extreme ultraviolet: can they mitigate three-dimensional mask effects?

Perspectives and tradeoffs of absorber materials for high NA EUV lithography

Contact Info

Product

Resources

About

Reduction of PdO/Al₂O₃ in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS

Reduction of PdO/Al₂O₃ in Liquid Cyclohexane Followed In Situ by ATR-IR, High-Energy XRD, and XAS