The coherent EUV scatterometry microscope for actinic mask inspection and metrology

Harada, Tetsuo; Nakasuji, Masato; Kimura, Teruhiko; Nagata, Yutaka; Watanabe, Takeo; Kinoshita, Hiroo

doi:10.1117/12.896576

Cited by 24 publications

(15 citation statements)

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“…Several groups apply actinic wavelength inspections 8,9,10 . The actinic wavelength (13.5 nm) measurement is very powerful to characterize CD and inhomogeneities in the multilayer stack of EUV masks.…”

Section: Introductionmentioning

confidence: 99%

Sensitivity analysis for OMOG and EUV photomasks characterized by UV-NIR spectroscopic ellipsometry

Heinrich

Dirnstorfer

Bischoff³

et al. 2013

SPIE Proceedings

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We investigated the potentials, applicability and advantages of spectroscopic ellipsometry (SE) for the characterization of high-end photomasks. The SE measurements were done in the ultraviolet-near infrared (UV-NIR) wavelength range from 300 nm to 980 nm, at angle of incidences (AOI) between 10 and 70° and with a microspot size of 45 x 10 µm² (AOI=70°). The measured and spectra were modeled using the rigorous coupled wave analysis (RCWA) to determine the structural parameters of a periodic array, i.e. the pitch and critical dimension (CD). Two different types of industrial photomasks consisting of line/space structures were evaluated, the reflecting extreme ultraviolet (EUV) and the transmitting opaque MoSi on glass (OMOG) mask. The and spectra of both masks show characteristic differences, which were related to the Rayleigh singularities and the missing transmission diffraction in the EUV mask. In the second part of the paper, a simulation based sensitivity analysis of the Fourier coefficients and is presented, which is used to define the required measurement precision to detect a CD deviation of 1%. This study was done for both mask types to investigate the influence of the stack transmission. It was found that sensitivities to CD variations are comparable for OMOG and EUV masks. For both masks, the highest sensitivities appear close to the Rayleigh singularities and significantly increase at very low AOI. To detect a 1% CD deviation for pitches below 150 nm a measurement precision in the order of 0.01 is required. This measurement precision can be realized with advanced optical hardware. It is concluded that UV-NIR ellipsometry is qualified to characterize photomasks down to the 13 nm technology node in 2020.

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Section: Introductionmentioning

confidence: 99%

Sensitivity analysis for OMOG and EUV photomasks characterized by UV-NIR spectroscopic ellipsometry

Heinrich

Dirnstorfer

Bischoff³

et al. 2013

SPIE Proceedings

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“…[16][17][18][19][20] The sample phase defect was exposed using coherent EUV light, and the diffracted light was recorded using a CCD camera. To reconstruct the pattern image, the phase information of the diffraction image is required, but this information is not recorded.…”

Section: Introductionmentioning

confidence: 99%

Phase defect characterization on an extreme-ultraviolet blank mask using microcoherent extreme-ultraviolet scatterometry microscope

Harada¹,

Tanaka²,

Watanabe³

et al. 2013

Journal of Vacuum Science & Technology B, Nanotechnology an

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“…Gerchberg-Saxton 13 and HIO methods have been adopted in several recent studies 1,3,5,[14][15][16][17][18][19][20] for mask inspection in EUVL. Harada et al 1,14,17 reported the development of coherent scatterometry microscope to characterize mask defect.…”

Section: Application Of Hybrid Input-output For Mask Inspectionmentioning

confidence: 99%

“…1 As the structures of masks present features much finer than the wavelength, a conventional imaging system cannot be used even though methods relying on deep ultraviolet illumination were proposed. 2 Coherent diffraction imaging methods 1,3 have been proposed for defect inspection. However, in this case, mask shape is not directly obtained.…”

Section: Introductionmentioning

confidence: 99%

Accurate characterization of mask defects by combination of phase retrieval and deterministic approach

et al. 2016

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Abstract. We present a method to characterize not only shape but also depth of defects in line and space mask patterns. Features in a mask are too fine for a conventional imaging system to resolve them and a coherent imaging system providing only the pattern diffracted by the mask is used. Then phase retrieval methods may be applied, but the accuracy is too low to determine the exact shape of the defect. Deterministic methods have been proposed to accurately characterize the defect, but this requires a reference pattern. We propose to use a phase retrieval algorithm to retrieve the general shape of the mask and then apply a deterministic approach to precisely characterize the defects detected. © 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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The coherent EUV scatterometry microscope for actinic mask inspection and metrology

Cited by 24 publications

References 0 publications

Sensitivity analysis for OMOG and EUV photomasks characterized by UV-NIR spectroscopic ellipsometry

Sensitivity analysis for OMOG and EUV photomasks characterized by UV-NIR spectroscopic ellipsometry

Phase defect characterization on an extreme-ultraviolet blank mask using microcoherent extreme-ultraviolet scatterometry microscope

Accurate characterization of mask defects by combination of phase retrieval and deterministic approach

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