CD-Metrology of EUV masks in the presence of charging: measurement and simulation

Babin, S.; Borisov, S. S.; Hakii, Hidemitsu; Nishiyama, Yasushi; Yonekura, Isao

doi:10.1117/12.999462

Cited by 5 publications

(6 citation statements)

References 3 publications

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“…These simulations take into account charging and discharging effects, electromagnetic fields, detector configurations, and so on. [1][2][3][4] The simulated results are consistent with the experimental results and can describe the physical phenomena of extreme ultraviolet (EUV) mask imaging and metrology. 3,4 As the pattern size of the EUV mask shrinks, thin absorber defects from etching residue tend to become more discernible.…”

Section: Introductionsupporting

confidence: 89%

Identification of residual-type defect on extreme ultraviolet mask by projection electron microscope using Monte Carlo simulation

Iida¹,

Amano²,

Hirano³

et al. 2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

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Thin absorber defects called residual-type defects are etching residues that tend to become more discernible as the pattern size of the extreme ultraviolet (EUV) mask shrinks. Projection electron microscope (PEM) images of the residual-type defects with various thicknesses were investigated using Monte Carlo simulation. In the case of the secondary electron image, the thickness of the defect was identified by the defect's signal intensity. It was found that the material and its relative thickness affected the signal intensity. In the case of the mirror electron image, three kinds of defects were selectively identified by controlling the primary electron energy. When the energy distribution of the primary electrons was taken into account, these defects were identified by the defects' signal intensities. It was found that the surface potential of the residual-type defects on the EUV mask greatly affected the mirror electron image. These results suggest that the thickness of the residual-type defect is identifiable by the PEM technique, and the defect selectivity is greatly affected by the thickness of the oxide layer when mirror electrons are used.

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Section: Introductionsupporting

confidence: 89%

Identification of residual-type defect on extreme ultraviolet mask by projection electron microscope using Monte Carlo simulation

Iida¹,

Amano²,

Hirano³

et al. 2012

Journal of Vacuum Science &Amp; Technology B, Nanotechnology and Microelectronics: Materials, Processing, Measurement, and Phen

View full text Add to dashboard Cite

show abstract

“…These simulations take into account the charging and discharging effects, electromagnetic fields, detector configurations, and so on. [8][9][10][11][12] The simulated results are consistent with experimental results and can describe the physical phenomena of EUV mask imaging and metrology. 11,12 In this study, we describe defect detection using simulated PEM image by Monte Carlo simulation.…”

Section: Introductionsupporting

confidence: 78%

Extreme ultraviolet mask defect inspection with a half pitch 16-nm node using simulated projection electron microscope images

Iida¹,

Amano²,

Hirano³

et al. 2013

J. Micro/Nanolith. MEMS MOEMS

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Abstract. According to an International Technology Roadmap for Semiconductors (ITRS-2012) update, the sensitivity requirement for an extreme ultraviolet (EUV) mask pattern inspection system is to be less than 18 nm for half pitch (hp) 16-nm node devices. The inspection sensitivity of extrusion and intrusion defects on hp 64-nm line-andspace patterned EUV mask were investigated using simulated projection electron microscope (PEM) images. The obtained defect images showed that the optimization of current density and image processing techniques were essential for the detection of defects. Extrusion and intrusion defects 16 nm in size were detected on images formed by 3000 electrons per pixel. The landing energy also greatly influenced the defect detection efficiency. These influences were different for extrusion and intrusion defects. These results were in good agreement with experimentally obtained yield curves of the mask materials and the elevation angles of the defects. These results suggest that the PEM technique has a potential to detect 16-nm size defects on an hp 64-nm patterned EUV mask. © The Authors.Published by SPIE under a Creative Commons Attribution 3.0 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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“…In the case of extreme ultraviolet (EUV) masks, the patterns are fabricated on their EUV reflective multilayer (ML). [15][16][17] In the earlier words, the authors had shown that the effect of incident beam energy on the defect detectability of EUV mask became more pronounced as the defect size and their thickness became small. 9 EB technology is widely used for the inspection of patterned EUV masks [10][11][12][13][14] and in measurement of critical dimensions (CD-metrology) of the EUV masks.…”

Section: Introductionmentioning

confidence: 99%

Impact of electron scattering in extreme ultraviolet reflective multilayer on electron image

Iida¹,

Amano²,

Hirano³

et al. 2013

Journal of Vacuum Science & Technology B, Nanotechnology an

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Articles you may be interested inQuantitative analysis of electron energy loss spectra and modelling of optical properties of multilayer systems for extreme ultraviolet radiation regime Impact of electron scattering in extreme ultraviolet reflective multilayer (ML) on electron image was investigated. The secondary electron emission coefficient of Ru capped ML was lower than that of Ru bulk layer when the incident electron energy was more than 0.5 keV. In ML, the backscattered electrons (BSEs) diffused laterally along the Si layer and escaped from the Ru surface, while generating secondary electrons. As a result, spatial intensity distribution of the emitted electrons within the ML sample was broader than that of the Ru bulk sample. The deep and broad undershot dip appeared in the profile of scanning electron microscope image for knife-edge pattern on ML sample. This was because the BSEs near the edge diffused laterally and were blocked from escaping from the sample surface by the absorber layer. In the case of hp 50 nm line-and-space (L/S) pattern, dips appeared only for Ru bulk samples, because the dense L/S pattern profile is essentially a summation of two opposing knife-edges. Simulated diffusion lengths were in good agreements with experimentally obtained dip widths. The influential range of laterally diffusion effect was from 3 to 20 keV.

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CD-Metrology of EUV masks in the presence of charging: measurement and simulation

Cited by 5 publications

References 3 publications

Identification of residual-type defect on extreme ultraviolet mask by projection electron microscope using Monte Carlo simulation

Identification of residual-type defect on extreme ultraviolet mask by projection electron microscope using Monte Carlo simulation

Extreme ultraviolet mask defect inspection with a half pitch 16-nm node using simulated projection electron microscope images

Impact of electron scattering in extreme ultraviolet reflective multilayer on electron image

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