Need for LWR metrology standardization: the imec roughness protocol

Lorusso, Gian; Sutani, Takumichi; Rutigliani, Vito; Roey, Frieda Van; Moussa, Alain; Charley, Anne-Laure; Mack, Chris A.; Naulleau, Patrick; Perera, Chami; Constantoudis, Vassilios; Ikota, Masami; Ishimoto, Toru; Koshihara, Shunsuke

doi:10.1117/1.jmm.17.4.041009

Cited by 41 publications

(52 citation statements)

References 12 publications

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“…There is, however, an obvious correct setting for the use of filtering: none (all filtering/smoothing turned off ). 13 The use of inverse linescan modeling for edge detection was employed in this work to enable robust edge detection without the use of filtering, with the added benefit of making the results independent of the edge detection threshold value. 11 This work carries on a previous effort 5 to look at the four sets of CD-SEM parameters mentioned above to access the accuracy of roughness metrology.…”

Section: Discussionmentioning

confidence: 99%

Unbiased roughness measurements: Subtracting out SEM effects, part 2

Lorusso

Rutigliani

Roey

et al. 2018

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

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The measurement of roughness of small lithographic patterns is biased by noise in the scanning electron microscopes (SEMs) used to make the measurements. Unbiasing the roughness measurement requires the measurement and subtraction of the image noise based on its unique frequency behavior. Improvement to prior white noise removal is achieved by applying a pink noise model. This pink noise removal technique was applied to roughness measurements made with different electron doses (frames of integration), different operating voltages, and different generations of SEM tools. Effective noise removal to create accurate unbiased estimates of the roughness was achieved over a wider range of SEM tool parameter settings than has been previously achieved. As a result, unbiased roughness measurements can now be used to characterize and improve stochastic variability in semiconductor lithography and patterning.

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Section: Discussionmentioning

confidence: 99%

Unbiased roughness measurements: Subtracting out SEM effects, part 2

Lorusso

Rutigliani

Roey

et al. 2018

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

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“…Following exposure, development, and further post-processing, patterned features are inspected on-site with a newly-commissioned SEM (Hitachi Regulus 8230). SEM parameters have been calibrated as closely as possible to IMEC's roughness protocol 17 . Subsequent key-parameters are shown in Table 1 Acquired dose-dependent CD and LWRunb values are then linearly fitted to determine pitch-specific DtS and corresponding LWRunb values, as is presented in Figure 3.…”

Section: Resist Screening Methodsmentioning

confidence: 99%

Progress in EUV-interference lithography resist screening towards the deployment of high-NA lithography

Allenet

Wang

Vockenhuber

et al. 2021

Extreme Ultraviolet (EUV) Lithography XII

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The development of EUV resists is one of the major challenges for the deployment of high-NA EUV lithography , which is on the roadmap for high-volume manufacturing of future semiconductor technology nodes. Resist performance is admittedly governed by a resolution-roughness-sensitivity (RLS) tradeoff. This study reports on the EUV resist progress achieved during the last year in the framework of the resist screening program by PSI and ASM L. An extensive performance characterization of different resists was carried out using the XIL-II beamline EUV interference lithography (EUV-IL) tool at the Swiss Light Source (SLS). We present the upgraded screening metrology used in 2020 at PSI enabling increased confidence in results. We report material performance towards patterning lines/spaces features with respect to the key parameters of RLS: half-pitch (HP), dose-to-size (DtS), line-width-roughness (LWR), as well as Z-factor for overall performance consideration. General progress in EUV resist development is reviewed by considering several resist platforms available today from different vendors. Different molecular and chemically amplified resist materials are demonstrated as viable for 16 nm resolution technology nodes. One chemically-amplified resist vendor shows suitable materials for 13-nm-resolution technologies while exhibiting potential for further downscaling. We present different metal-oxide resists screening with resolutions down to 10 nm HP. We finally discuss the overall progress of materials achieved between 2019 and 2020 towards reaching high-NA.

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“…Therefore, quantitatively investigating the error is vital. 1 LER is often evaluated using three times the standard deviation (3σ) of the distances between points forming a line-edge profile and its fitted linear line. To completely characterize a line-edge profile, the roughness exponent (α) and correlation length (ξ) are required in addition to σ.…”

Section: Introductionmentioning

confidence: 99%

Direct comparison of line edge roughness measurements by SEM and a metrological tilting-atomic force microscopy for reference metrology

Kizu

Misumi

Hirai

et al. 2020

J. Micro/Nanolith. MEMS MOEMS

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Background: Conventional scanning electron microscopy (SEM) that is used for 2D top-view metrology, a classical line edge roughness (LER) measurement technique, is incapable of measuring 3D structures of a nanoscale line pattern. For LER measurements, SEM measurement generates a single line-edge profile for the 3D sidewall roughness, although the line-edge profile differs at each height in the 3D sidewall. Aim: To develop an evaluation method of SEM-based LER measurement techniques and to verify how the 3D sidewall shape is reflected in the SEM's 2D result. Approach: Direct comparison by measuring an identical location of a line pattern by SEM and an atomic force microscopy (AFM) with the tip-tilting technique that is capable of measuring the 3D sidewall. The line pattern has vertical stripes on the sidewall due to its fabrication process. Measured line edge profiles were analyzed using power spectral density, height-height correlation function, and autocorrelation function. Results: Line edge profiles measured by SEM and AFM were well matched except for noise level. Frequency and scaling analyses showed that SEM profile contained high noise and had lost a property of self-affine fractals in contrast to AFM. Conclusions: In the case of the line pattern with vertical stripes on the sidewall, SEM profile is generally consistent with 3D sidewall shape. The AFM-based LER measurement technique is useful as LER reference metrology to evaluate other LER measurement techniques.

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Need for LWR metrology standardization: the imec roughness protocol

Cited by 41 publications

References 12 publications

Unbiased roughness measurements: Subtracting out SEM effects, part 2

Unbiased roughness measurements: Subtracting out SEM effects, part 2

Progress in EUV-interference lithography resist screening towards the deployment of high-NA lithography

Direct comparison of line edge roughness measurements by SEM and a metrological tilting-atomic force microscopy for reference metrology

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