Mathematical modelling of indirect measurements in scatterometry

Gross, Hermann; Model, Regine; Bär, Markus; Wurm, Matthias; Bodermann, Bernd; Rathsfeld, Andreas

doi:10.1016/j.measurement.2006.04.009

Cited by 74 publications

(50 citation statements)

References 20 publications

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“…Some of the most widely used configurations are single incidence angle reflectometry, 2-Θ scatterometry, spectroscopic ellipsometry, Fourier scatterometry, interferometric Fourier scatterometry,etc., [7][8][9][10][11][12][13][14][15] with a wide range of applications [16][17][18][19][20]. In an earlier paper, it has been predicted theoretically how, and under which conditions, CFS can be more sensitive than the classical IOS [21].…”

Section: Introductionmentioning

confidence: 99%

Reconstruction of sub-wavelength features and nano-positioning of gratings using coherent Fourier scatterometry

et al. 2014

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Abstract:Optical scatterometry is the state of art optical inspection technique for quality control in lithographic process. As such, any boost in its performance carries very relevant potential in semiconductor industry. Recently we have shown that coherent Fourier scatterometry (CFS) can lead to a notably improved sensitivity in the reconstruction of the geometry of printed gratings. In this work, we report on implementation of a CFS instrument, which confirms the predicted performances. The system, although currently operating at a relatively low numerical aperture (NA = 0.4) and long wavelength (633 nm) allows already the reconstruction of the grating parameters with nanometer accuracy, which is comparable to that of AFM and SEM measurements on the same sample, used as reference measurements. Additionally, 1 nm accuracy in lateral positioning has been demonstrated, corresponding to 0.08% of the pitch of the grating used in the actual experiment.

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Section: Introductionmentioning

confidence: 99%

Reconstruction of sub-wavelength features and nano-positioning of gratings using coherent Fourier scatterometry

et al. 2014

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“…In conventional incoherent optical scatterometry (IOS), light from an incoherent source interacts with the scatterer and the diffracted far field intensity map is recorded [1,2]. The energy distribution in the diffracted far field depends on the material composition and the geometrical properties of the scatterer that one wants to reconstruct.…”

Section: Introductionmentioning

confidence: 99%

Phase retrieval between overlapping orders in coherent Fourier scatterometry using scanning

Kumar¹,

Gawhary²,

Roy³

et al. 2013

J. Eur. Opt. Soc.-Rapid Publ.

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Non-interferometric phase retrieval from the intensity measurements in Coherent Fourier Scatterometry (CFS) is presented using a scanning focused spot. Formulae to determine the state of polarization of the scattered light and to retrieve the phase difference between overlapping scattered orders are given. The scattered far field is rigorously computed and the functionality of the method is proved with experimental results.

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“…Rigorous coupled-wave analysis (RCWA) 7,8,9,10,11 , which is still widely used, is limited to gratings consisting of stacks of rectangular structures. We use the finite element method (FEM) 12,13,14,15,16 which allows the modeling of arbitrarily shaped structures and for potentially higher accuracy as compared to the RCWA method 17 . l detector with slit á" tigigs 1llir aperture sample with line structure…”

Section: Introductionmentioning

confidence: 99%

Comparison of CD measurements of an EUV photomask by EUV scatterometry and CD-AFM

et al. 2013

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EUV scatterometry is a potential high-throughput measurement method for the characterization of EUV photomask structures. We present a comparison of angle resolved extreme ultraviolet (EUV) scatterometry and critical dimension atomic force microscope (CD-AFM) as a reference metrology for measurements of geometrical parameters like line width (CD), height and sidewall angle of EUV photomask structures. The structures investigated are dense and semidense bright and dark lines with different nominal CDs between 140 nm and 540 nm. The results show excellent linearity of the critical dimension measured with both methods within a range of only 1.8 nm and an offset of the absolute values below 3 nm. A maximum likelihood estimation (MLE) method is used to reconstruct the shape parameters and to estimate their uncertainties from the measured scattering efficiencies. The newly developed CD-AFM at PTB allows versatile measurements of parameters such as height, CD, sidewall angle, line edge/width roughness, corner rounding, and pitch. It applies flared tips to probe steep and even undercut sidewalls and employs a new vector approaching probing (VAP) strategy which enables very low tip wear and high measurement flexibility. Its traceability is ensured by a set of calibrated step-height and reference CD standards.

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Mathematical modelling of indirect measurements in scatterometry

Cited by 74 publications

References 20 publications

Reconstruction of sub-wavelength features and nano-positioning of gratings using coherent Fourier scatterometry

Reconstruction of sub-wavelength features and nano-positioning of gratings using coherent Fourier scatterometry

Phase retrieval between overlapping orders in coherent Fourier scatterometry using scanning

Comparison of CD measurements of an EUV photomask by EUV scatterometry and CD-AFM

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