Intra-field patterning control using high-speed and small-target optical metrology of CD and focus

Cramer, Hugo; Petra, S.J.H.; Auer, Bastiaan Onne Fagginger; Smilde, Henk-Jan H.; Wisse, Baukje; Welch, Steven; Kruijswijk, Stefan; Hinnen, Paul; Segers, Bart; Leewis, Christian; Staals, Frank; Marun, M. Escalante; Young, S.; Guo, Wei; Boef, Arie den

doi:10.1117/12.2085957

Cited by 3 publications

(6 citation statements)

References 8 publications

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“…Similarly, the 10 wavelengths-wide buffer areas should also lead to a decreased width. From wavelength scaling it should be possible to reduce the scatterfield microscopy target down to an area below 7 μm × 3 μm at λ = 193 nm, which if possible would represent a factor of fifteen less area than the 12 μm × 12 μm scatterometry target from Ref [11]. …”

Section: Scatterfield Microscopymentioning

confidence: 99%

“…When the beam overfills the target, “spurious” scattering and reflections arise that must be dealt with, although some metrology systems collect not only the 0 th order-scattering but also the ±1 st orders to augment their CD measurements [4]. Research is leading to reductions in the size of scatterometry targets, with some recent projections of targets as small as 12 μm × 12 μm in area for CD scatterometry [11] and 10 μm × 10 μm for diffraction-based overlay metrology [12]. …”

Section: Introductionmentioning

confidence: 99%

“…Addition of these buffers increases the area of this initial proposed target at 450 nm wavelength to 10.8 μm × 6.9 μm, smaller than the 12 μm × 12 μm scatterometry targets for CD metrology in Ref. [11] above.…”

Section: Introductionmentioning

confidence: 99%

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Enabling quantitative optical imaging for in-die-capable critical dimension targets

et al. 2016

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Dimensional scaling trends will eventually bring semiconductor critical dimensions (CDs) down to only a few atoms in width. New optical techniques are required to address the measurement and variability for these CDs using sufficiently small in-die metrology targets. Recently, Qin et al. [Light Sci Appl, 5, e16038 (2016)] demonstrated quantitative model-based measurements of finite sets of lines with features as small as 16 nm using 450 nm wavelength light. This paper uses simulation studies, augmented with experiments at 193 nm wavelength, to adapt and optimize the finite sets of features that work as in-die-capable metrology targets with minimal increases in parametric uncertainty. A finite element based solver for time-harmonic Maxwell's equations yields two- and three-dimensional simulations of the electromagnetic scattering for optimizing the design of such targets as functions of reduced line lengths, fewer number of lines, fewer focal positions, smaller critical dimensions, and shorter illumination wavelength. Metrology targets that exceeded performance requirements are as short as 3 μm for 193 nm light, feature as few as eight lines, and are extensible to sub-10 nm CDs. Target areas measured at 193 nm can be fifteen times smaller in area than current state-of-the-art scatterometry targets described in the literature. This new methodology is demonstrated to be a promising alternative for optical model-based in-die CD metrology.

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Section: Scatterfield Microscopymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enabling quantitative optical imaging for in-die-capable critical dimension targets

et al. 2016

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“…A more conservative estimate of 6 μ m × 6 μ m would still result in a four-fold reduction in area compared to the 12 μ m × 12 μ m CD scatterometry target from Ref. [3]. However there is a possible trade off in time as real space images are collected at multiple focus heights, compared to a single image of the pupil plane for that CD scatterometry target.…”

mentioning

confidence: 99%

“…When the beam overfills the target, “spurious” scattering and reflections arise that must be dealt with, although some metrology systems collect not only the 0 th order-scattering but also the ± 1 st orders to augment their CD measurements [2]. Research is leading to reductions in the size of scatterometry targets, with some recent projections of targets as small as 12 μ m × 12 μ m in area for CD scatterometry [3] and 10 μ m × 10 μ m for diffraction-based overlay metrology [4]. …”

mentioning

confidence: 99%

Optimizing the nanoscale quantitative optical imaging of subfield scattering targets

et al. 2016

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The full 3-D scattered field above finite sets of features has been shown to contain a continuum of spatial frequency information, and with novel optical microscopy techniques and electromagnetic modeling, deep-subwavelength geometrical parameters can be determined. Similarly, by using simulations, scattering geometries and experimental conditions can be established to tailor scattered fields that yield lower parametric uncertainties while decreasing the number of measurements and the area of such finite sets of features. Such optimized conditions are reported through quantitative optical imaging in 193 nm scatterfield microscopy using feature sets up to four times smaller in area than state-of-the-art critical dimension targets.

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Appraising the Extensibility of Optics-Based Metrology for Emerging Materials

Barnes¹,

Henn²,

Sohn³

et al. 2019

ECS Trans.

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To advance computational capabilities beyond conventional scaling limitations, novel device architectures enabled by emerging materials may be required. Optics-based methodologies, central to modern-day process control, will be pursued by the nanoelectronics industry to interrogate these devices as optics are inexpensive, nondestructive, and fast. As geometrical and material complexity define new metrology requirements, these should be considered relative to the broader challenge of perpetuating optical methods for deep-subwavelength features. Using examples from our group and from others, the tailoring of the illumination conditions, sample, collection path, and data analysis are emphasized for model-based quantitative measurements. The successful fitting of structures comprised from these emerging materials will require the accurate determination of material optical constants, which may be both thickness dependent and anisotropic. Atomistic models such as tight-binding calculations or density-functional theory are potential approaches for understanding the dielectric function of these materials.

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Intra-field patterning control using high-speed and small-target optical metrology of CD and focus

Cited by 3 publications

References 8 publications

Enabling quantitative optical imaging for in-die-capable critical dimension targets

Enabling quantitative optical imaging for in-die-capable critical dimension targets

Optimizing the nanoscale quantitative optical imaging of subfield scattering targets

Appraising the Extensibility of Optics-Based Metrology for Emerging Materials

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