Electron beam inspection of 16nm HP node EUV masks

Shimomura, T.; Narukawa, Shogo; Abe, Tsukasa; Takikawa, Tadahiko; Hayashi, Naoya; Wang, Fei; Ma, Long; Lin, Chia-Wen; Zhao, Yan; Kuan, Chiyan; Jau, Jack

doi:10.1117/12.976017

Cited by 4 publications

(2 citation statements)

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“…[15][16][17][18][19][20][21][22] PEM is one of the electron microscope techniques that is based upon the imaging EO, and has an advantage of giving a considerably higher throughput than achievable in the case of conventional scanning electron microscope (SEM) type inspection system. 23) That is because PEM probes a sample target with areal illumination, whereas SEM probes a sample with a spot beam. Furthermore, the impact of the surface potential inhomogeneity on the PEM image degradation of EUV mask could be less than the degradation on the ULSI wafer because a several nm thick Ta 2 O 5 is the only insulator in EUV mask.…”

Section: Introductionmentioning

confidence: 99%

Analysis of image distortion on projection electron microscope image

Iida¹,

Hirano²,

Terasawa³

et al. 2014

Jpn. J. Appl. Phys.

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Distortion of image obtained from a projection electron microscope (PEM) was investigated using an upgraded Monte Carlo simulation assembled with electron imaging optics (EO) data. A simulated PEM image distortion was reconstructed by the imaging on the image-plane through the EO. The image distortion was created by a local field effect (Type II). The displacement of lines, contrast degradation, and changes in the line widths were simultaneously observed. In the case of a negative charge condition, these image degradations were enhanced by an increased gradient of the electric field produced by a local charge and an extraction voltage. The image distortion and the associated image degradation were improved by applying a 7.5-times higher extraction voltage.

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Section: Introductionmentioning

confidence: 99%

Analysis of image distortion on projection electron microscope image

Iida¹,

Hirano²,

Terasawa³

et al. 2014

Jpn. J. Appl. Phys.

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“…3,4 Therefore, a clear understanding of electron scattering in sample targets is necessary for the optimization of the electron beam energy. 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. In previous works, the impact of electron scattering in the ML on the exposed resist profile have been widely investigated for the optimization of the proximity effect correction (PEC) [6][7][8] and of mask process correction (MPC).…”

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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Pattern inspection of etched multilayer extreme ultraviolet mask

Iida¹,

Hirano²,

Amano³

et al. 2016

J. Micro/Nanolith. MEMS MOEMS

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Abstract. Patterned mask inspection for an etched multilayer (ML) extreme ultraviolet mask was investigated. In order to optimize the mask structure from the standpoint of a pattern inspection the mask structure not only from the standpoint of a pattern inspection by using a projection electron microscope but also by using a projection electron microscope but also by considering the other fabrication processes using electron beam techniques such as critical dimension metrology and mask repair, we employed a conductive layer between the ML and substrate. By measuring the secondary electron emission coefficients of the candidate materials for the conductive layer, we evaluated the image contrast and the influence of the charging effect. In the cases of 40-pair ML, 16-nm-sized extrusion and intrusion defects were found to be detectable more than 10 sigma in half pitch 44, 40, and 32 nm line-and-space patterns. Reducing 40-pair ML to 20-pair ML degraded the image contrast and the defect detectability. However, by selecting B 4 C as a conductive layer, 16-nm-sized defects and etching residues remained detectable. The 16-nm-sized defects were also detected after the etched part was refilled with Si. A double-layer structure with 2.5-nm-thick B 4 C on metal film used as a conductive layer was found to have sufficient conductivity and also was found to be free from the surface charging effect and influence of native oxide. © 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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Electron beam inspection of 16nm HP node EUV masks

Cited by 4 publications

References 0 publications

Analysis of image distortion on projection electron microscope image

Analysis of image distortion on projection electron microscope image

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

Pattern inspection of etched multilayer extreme ultraviolet mask

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