Use of EUV scatterometry for the characterization of line profiles and line roughness on photomasks

Scholze, Frank; Laubis, Christian

doi:10.1117/12.798934

Cited by 14 publications

(13 citation statements)

References 8 publications

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“…Surface analysis becomes extremely precise by means of reflectometry and scatterometry [4,5,6] and also the binding state of molecules can be studied by spectral investigations [7,8,9]. Microscopy with radiation at wavelengths in the water window (λ = 2.3 .…”

Section: Introductionmentioning

confidence: 99%

Radiation characteristics of extreme UV and soft X-ray sources

Mey¹

2015

Göttingen Series in X-Ray Physics

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Section: Introductionmentioning

confidence: 99%

Radiation characteristics of extreme UV and soft X-ray sources

Mey¹

2015

Göttingen Series in X-Ray Physics

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“…corner rounding, footing, roughness (both surface, LER and LWR) and further edge profile details, if appropriate. To provide the sensitivity required especially in the high spatial frequency regime, we started to investigate both the exploitation of the advantages of using shorter wavelengths ranging from the deep UV over extreme ultraviolet (DUV, EUV) down to X-rays [9][10][11], and the development and exploration of new methods like Fourier scatterometry, Mueller polarimetry. Further on we are going to perform comparison measurements applying both these novel scatterometry methods and conventional scatterometry methods on different test samples both with 1D and 2D grating structures to compare the metrological potential of each method, to test their respective sensitivity regarding the different structure details and to evaluate the results with respect to traceability of scatterometry.…”

Section: Methodical Extensions In Scatterometric Measurement Capabilimentioning

confidence: 99%

First steps towards a scatterometry reference standard

Bodermann

Hansen²,

Burger³

et al. 2012

SPIE Proceedings

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Supported by the European Commission and EURAMET, a consortium of 10 participants from national metrology institutes, universities and companies has recently started a joint research project with the aim of overcoming current challenges in optical scatterometry for traceable linewidth metrology and to establish scatterometry as a traceable and absolute metrological method for dimensional measurements. This requires a thorough investigation of the influence of all significant sample, tool and data analysis parameters, which affect the scatterometric measurement results. For this purpose and to improve the tool matching between scatterometers, CD-SEMs and CD-AFMs, experimental and modelling methods will be enhanced. The different scatterometry methods will be compared with each other and with specially adapted atomic force microscopy (AFM) and scanning electron microscopy (SEM) measurement systems. Additionally novel methods for sophisticated data analysis will be developed and investigated to reach significant reductions of the measurement uncertainties in critical dimension (CD) metrology. To transfer traceability to industrial applications of scatterometry an important step and one final goal of this project is the realisation of different waferbased reference standard materials for calibration of scatterometers. The approaches to reach these goals and first design considerations and preliminary specification of the scatterometry standards are presented and discussed.

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“…11,17 For the EUV mask investigated there, a CD uniformity of typically 3.6 nm (3σ) was measured by SEM. 12 Therefore, the sidewall angles could have been underestimated by about 3 • if the deviations shown in table 2 were scaled linearly. …”

Section: Inverse Scatterometric Problemmentioning

confidence: 97%

The effect of line roughness on the reconstruction of line profiles for EUV masks from EUV scatterometry

Kato

Scholze

2010

SPIE Proceedings

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The development of EUV lithography is critically based on the availability of suitable metrology equipment. The Physikalisch-Technische Bundesanstalt (PTB) operates an EUV reflectometry facility at the electron storage ring BESSY II, particularly to support the development of Extreme Ultraviolet Lithography. It has been shown that EUV scatterometry is a versatile metrology for characterizing periodic structures regarding critical dimension (CD) and other profile properties. The short wavelength of EUV is particularly advantageous, since it increases the sensitivity to structure roughness. On the other hand, structure roughness also modifies the diffraction intensities used for structure reconstruction based on rigorous calculations of EUV diffraction. We present here first investigations of the influence of roughness-induced modifications of diffraction intensities on the subsequent reconstruction of line profiles. A method is developed to numerically estimate changes in measured diffraction intensities induced by line edge and line width roughness. Finally, the reconstructed profiles for undisturbed and disturbed diffraction intensities are compared. For absorber lines of trapezoidal cross section, the height and mean CD at 50% height appear to be rather insensitive even for unrealistically large roughness amplitudes of up to 14 nm 1σ. The sidewall angle, however, decreases significantly with increasing roughness, with a particular sensitivity to line edge roughness as compared to line width roughness.

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Use of EUV scatterometry for the characterization of line profiles and line roughness on photomasks

Cited by 14 publications

References 8 publications

Radiation characteristics of extreme UV and soft X-ray sources

Radiation characteristics of extreme UV and soft X-ray sources

First steps towards a scatterometry reference standard

The effect of line roughness on the reconstruction of line profiles for EUV masks from EUV scatterometry

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