Novel EUV mask absorber evaluation in support of next-generation EUV imaging

Vicky Philipsen, Kim Vu Luong, Karl Opsomer, Christophe Detavernier, Eric Hendrickx, Andreas Erdmann, Peter Evanschitzky, Robbert W.E. Van De Kruijs, Zahra Heidarnia-Fathabad, Frank Scholze, Christian Laubis

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

4 Citations (Scopus)

Abstract

In next-generation EUV imaging for foundry N5 dimensions and beyond, inherent pitch- and orientation-dependent effects on wafer level will consume a significant part of the lithography budget using the current Ta-based mask. Mask absorber optimization can mitigate these so-called mask 3D effects. Thin metal absorbers like Ni and Co have been experimentally investigated due to their high EUV absorption, but they pose challenges on the current technology of subtractive mask patterning [1]. A simulation study of attenuated EUV phase shift masks has identified through multiobjective optimization superior imaging solutions for specific use cases and illumination conditions [2]. Evaluating novel EUV mask absorbers evolves on two levels, demonstrating (1) improvements from lithographic perspective and (2) compatibility with the full mask supply chain including material deposition, absorber patterning, scanner environment compatibility and mask lifetime. On the lithographic level, we have identified regions based on the material optical properties and their gain in imaging performance compared to the reference Ta-based absorber. Within each improvement region we engineered mask absorber materials to achieve both the required imaging capabilities, as well as the technical requirements for an EUV mask absorber. We discuss the material development of Te-based alloys and Ag-based layered structures, because of their high EUV extinction. For the attenuated phase shift materials, we start from a Ru-base material, due to its low refractive index, and construct Ru-alloys. On the experimental level, we examined our novel mask absorber materials against an initial mask absorber requirement list using an experimental test flow. Candidate materials are evaluated on film morphology and stability through thermal, hydrogen, EUV loading, and chemical cleaning, for their EUV optical constants by EUV reflectometry, as well as preliminary for selective dry etch. The careful mask absorber evaluation, combining imaging simulations and experimental material tests, allowed us to narrow down to promising combinations for novel EUV mask absorbers.

Original languageEnglish
Title of host publicationPhotomask Technology 2018
EditorsEmily E. Gallagher, Jed H. Rankin
PublisherSPIE
Volume10810
ISBN (Electronic)9781510622159
DOIs
Publication statusPublished - 10 Oct 2018
Event2018 SPIE Photomask Technology - Monterey, United States
Duration: 17 Sep 201819 Sep 2018

Publication series

NameProceedings of SPIE - The International Society for Optical Engineering
Volume10810
ISSN (Print)0277-786X
ISSN (Electronic)1996-756X

Conference

Conference2018 SPIE Photomask Technology
CountryUnited States
CityMonterey
Period17/09/1819/09/18

Fingerprint

EUV Mask
Absorber
Mask
Masks
absorbers
masks
Imaging
Imaging techniques
evaluation
Evaluation
absorbers (materials)
Patterning
Phase Shift
Compatibility
Phase shift
compatibility
Optical Constants
Reflectometry
phase shift
chemical cleaning

Keywords

  • absorber characterization
  • EUV mask absorber
  • mask 3D effects
  • rigorous mask 3D lithography simulation

Cite this

Philipsen, V., Luong, K. V., Opsomer, K., Detavernier, C., Hendrickx, E., Erdmann, A., ... Laubis, C. (2018). Novel EUV mask absorber evaluation in support of next-generation EUV imaging. In E. E. Gallagher, & J. H. Rankin (Eds.), Photomask Technology 2018 (Vol. 10810). [108100C] (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 10810). SPIE. https://doi.org/10.1117/12.2501799
Philipsen, Vicky ; Luong, Kim Vu ; Opsomer, Karl ; Detavernier, Christophe ; Hendrickx, Eric ; Erdmann, Andreas ; Evanschitzky, Peter ; Van De Kruijs, Robbert W.E. ; Heidarnia-Fathabad, Zahra ; Scholze, Frank ; Laubis, Christian. / Novel EUV mask absorber evaluation in support of next-generation EUV imaging. Photomask Technology 2018. editor / Emily E. Gallagher ; Jed H. Rankin. Vol. 10810 SPIE, 2018. (Proceedings of SPIE - The International Society for Optical Engineering).
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abstract = "In next-generation EUV imaging for foundry N5 dimensions and beyond, inherent pitch- and orientation-dependent effects on wafer level will consume a significant part of the lithography budget using the current Ta-based mask. Mask absorber optimization can mitigate these so-called mask 3D effects. Thin metal absorbers like Ni and Co have been experimentally investigated due to their high EUV absorption, but they pose challenges on the current technology of subtractive mask patterning [1]. A simulation study of attenuated EUV phase shift masks has identified through multiobjective optimization superior imaging solutions for specific use cases and illumination conditions [2]. Evaluating novel EUV mask absorbers evolves on two levels, demonstrating (1) improvements from lithographic perspective and (2) compatibility with the full mask supply chain including material deposition, absorber patterning, scanner environment compatibility and mask lifetime. On the lithographic level, we have identified regions based on the material optical properties and their gain in imaging performance compared to the reference Ta-based absorber. Within each improvement region we engineered mask absorber materials to achieve both the required imaging capabilities, as well as the technical requirements for an EUV mask absorber. We discuss the material development of Te-based alloys and Ag-based layered structures, because of their high EUV extinction. For the attenuated phase shift materials, we start from a Ru-base material, due to its low refractive index, and construct Ru-alloys. On the experimental level, we examined our novel mask absorber materials against an initial mask absorber requirement list using an experimental test flow. Candidate materials are evaluated on film morphology and stability through thermal, hydrogen, EUV loading, and chemical cleaning, for their EUV optical constants by EUV reflectometry, as well as preliminary for selective dry etch. The careful mask absorber evaluation, combining imaging simulations and experimental material tests, allowed us to narrow down to promising combinations for novel EUV mask absorbers.",
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author = "Vicky Philipsen and Luong, {Kim Vu} and Karl Opsomer and Christophe Detavernier and Eric Hendrickx and Andreas Erdmann and Peter Evanschitzky and {Van De Kruijs}, {Robbert W.E.} and Zahra Heidarnia-Fathabad and Frank Scholze and Christian Laubis",
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Philipsen, V, Luong, KV, Opsomer, K, Detavernier, C, Hendrickx, E, Erdmann, A, Evanschitzky, P, Van De Kruijs, RWE, Heidarnia-Fathabad, Z, Scholze, F & Laubis, C 2018, Novel EUV mask absorber evaluation in support of next-generation EUV imaging. in EE Gallagher & JH Rankin (eds), Photomask Technology 2018. vol. 10810, 108100C, Proceedings of SPIE - The International Society for Optical Engineering, vol. 10810, SPIE, 2018 SPIE Photomask Technology, Monterey, United States, 17/09/18. https://doi.org/10.1117/12.2501799

Novel EUV mask absorber evaluation in support of next-generation EUV imaging. / Philipsen, Vicky; Luong, Kim Vu; Opsomer, Karl; Detavernier, Christophe; Hendrickx, Eric; Erdmann, Andreas; Evanschitzky, Peter; Van De Kruijs, Robbert W.E.; Heidarnia-Fathabad, Zahra; Scholze, Frank; Laubis, Christian.

Photomask Technology 2018. ed. / Emily E. Gallagher; Jed H. Rankin. Vol. 10810 SPIE, 2018. 108100C (Proceedings of SPIE - The International Society for Optical Engineering; Vol. 10810).

Research output: Chapter in Book/Report/Conference proceedingConference contributionAcademicpeer-review

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AB - In next-generation EUV imaging for foundry N5 dimensions and beyond, inherent pitch- and orientation-dependent effects on wafer level will consume a significant part of the lithography budget using the current Ta-based mask. Mask absorber optimization can mitigate these so-called mask 3D effects. Thin metal absorbers like Ni and Co have been experimentally investigated due to their high EUV absorption, but they pose challenges on the current technology of subtractive mask patterning [1]. A simulation study of attenuated EUV phase shift masks has identified through multiobjective optimization superior imaging solutions for specific use cases and illumination conditions [2]. Evaluating novel EUV mask absorbers evolves on two levels, demonstrating (1) improvements from lithographic perspective and (2) compatibility with the full mask supply chain including material deposition, absorber patterning, scanner environment compatibility and mask lifetime. On the lithographic level, we have identified regions based on the material optical properties and their gain in imaging performance compared to the reference Ta-based absorber. Within each improvement region we engineered mask absorber materials to achieve both the required imaging capabilities, as well as the technical requirements for an EUV mask absorber. We discuss the material development of Te-based alloys and Ag-based layered structures, because of their high EUV extinction. For the attenuated phase shift materials, we start from a Ru-base material, due to its low refractive index, and construct Ru-alloys. On the experimental level, we examined our novel mask absorber materials against an initial mask absorber requirement list using an experimental test flow. Candidate materials are evaluated on film morphology and stability through thermal, hydrogen, EUV loading, and chemical cleaning, for their EUV optical constants by EUV reflectometry, as well as preliminary for selective dry etch. The careful mask absorber evaluation, combining imaging simulations and experimental material tests, allowed us to narrow down to promising combinations for novel EUV mask absorbers.

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Philipsen V, Luong KV, Opsomer K, Detavernier C, Hendrickx E, Erdmann A et al. Novel EUV mask absorber evaluation in support of next-generation EUV imaging. In Gallagher EE, Rankin JH, editors, Photomask Technology 2018. Vol. 10810. SPIE. 2018. 108100C. (Proceedings of SPIE - The International Society for Optical Engineering). https://doi.org/10.1117/12.2501799