Advancements in Ellipsometric and Scatterometric Analysis

O’Mullane, Samuel; Dixit, Dhairya; Diebold, Alain C.

doi:10.1201/9781315185385-5

Cited by 4 publications

(7 citation statements)

References 21 publications

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“…Scatterometry 78-80 is a non-imaging optical technique that allows sub-nanometre model-based measurements of overlay effects 81,82 , geometrical CDs and optical constants (e.g., n & k ) of patterned arrayed structures (Fig. 4a,b).…”

Section: Advanced Metrology Techniquesmentioning

confidence: 99%

Metrology for the next generation of semiconductor devices

Badaroglu²,

et al. 2018

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The semiconductor industry continues to produce ever smaller devices that are ever more complex in shape and contain ever more types of materials. The ultimate sizes and functionality of these new devices will be affected by fundamental and engineering limits such as heat dissipation, carrier mobility and fault tolerance thresholds. At present, it is unclear which are the best measurement methods needed to evaluate the nanometre-scale features of such devices and how the fundamental limits will affect the required metrology. Here, we review state-of-the-art dimensional metrology methods for integrated circuits, considering the advantages, limitations and potential improvements of the various approaches. We describe how integrated circuit device design and industry requirements will affect lithography options and consequently metrology requirements. We also discuss potentially powerful emerging technologies and highlight measurement problems that at present have no obvious solution.

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Section: Advanced Metrology Techniquesmentioning

confidence: 99%

Metrology for the next generation of semiconductor devices

Badaroglu²,

et al. 2018

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“…Minimization algorithms are utilized to vary the floating parameters in the optical model until the difference between calculated and measured spectra reaches a minimum. 18 There are multiple challenges related to optical modeling that may render the accurate extraction of desired parameters not feasible. First, the unit cell optical model is always an idealized replica of the measured features and therefore an approximation.…”

Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%

“…In addition, compositional variations as well as strain have an effect on the dielectric function and must be considered appropriately for accurate analyses. 18 Although each individual approximation of the above-mentioned challenges may only have a minor influence on the final geometric parameters of interest in a complex architecture, compounding effects can lead to unacceptable inaccuracies. It should be noted that, in state-of-the-art nanosheet transistor architectures, small volume changes need to be monitored with high accuracy.…”

Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%

“…Even though RCWA calculations are used because of their efficiency, depending on the complexity of the stack and the size of the unit cell, it can become computationally intensive. Minimization algorithms are utilized to vary the floating parameters in the optical model until the difference between calculated and measured spectra reaches a minimum 18 …”

Section: Scatterometry Challenges and Strategiesmentioning

confidence: 99%

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Spectral interferometry for fully integrated device metrology

Schmidt¹,

Medikonda²,

Rizzolo³

et al. 2023

J. Micro/Nanopattern. Mats. Metro.

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A spectral interferometry technique called vertical travelling scatterometry (VTS) is introduced, demonstrated, and discussed. VTS utilizes unique information from spectral interferometry and enables solutions for applications that are infeasible with traditional scatterometry approaches. The technique allows for data filtering related to spectral information from buried layers, which can then be ignored in the optical model. Therefore, using VTS, selective analyses of the topmost part of an arbitrarily complex stack are possible within a single metrology step. This methodology helps to overcome geometrical complexities and allows for focusing on parameters of interest through dramatically simplified optical modeling. Such model simplifications are specifically desired for back-end-of-line applications. Three examples are monitored discussed: (i) the critical dimensions (CDs) of a first metal level on top of nanosheet gate-all-around transistor structures, (ii) the thickness of an interlayer dielectric above embedded memory in the active area, and (iii) the CDs of trenches on top of tall stacks in the micrometer range comprising many layered dielectrics. It was found that, in all three cases, data filtering through VTS allowed for a simple optical model capable of delivering parameters of interest. The validity and accuracy of the VTS solution results were confirmed by extensive reference metrology obtained by traditional scatterometry, scanning electron microscopy, and transmission electron microscopy. Furthermore, it was shown that machine learning models trained with VTS filtered data can converge to a robust solution with a smaller dataset compared with models training with traditional scatterometry data.

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“…Methods based on scatterometry are used as in-line metrology [3,4]. Overlay metrology is used to characterize displacements between patterned layers with optical wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Line-Edge Roughness Using EUV Scatterometry

et al. 2022

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Smaller and more complex three-dimensional periodic nanostructures are part of the next generation of integrated electronic circuits. Additionally, decreasing the dimensions of nanostructures increases the effect of line-edge roughness on the performance of the nanostructures. Efficient methods for characterizing three-dimensional nanostructures are required for process control. Here, extreme-ultraviolet (EUV) scatterometry is exploited for the analysis of line-edge roughness from periodic nanostructures. In line with previous observations, differences are observed between line edge and line width roughness. The angular distribution of the diffuse scattering is an interplay of the line shape, the height of the structure, the roughness along the line, and the correlation between the lines. Unfortunately, existing theoretical methods for characterizing nanostructures using scatterometry do not cover all these aspects. Examples are shown here and the demands for future development of theoretical approaches for computing the angular distribution of the scattered X-rays are discussed.

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Advancements in Ellipsometric and Scatterometric Analysis

Cited by 4 publications

References 21 publications

Metrology for the next generation of semiconductor devices

Metrology for the next generation of semiconductor devices

Spectral interferometry for fully integrated device metrology

Analysis of Line-Edge Roughness Using EUV Scatterometry

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