Overlay control using scatterometry based metrology (SCOM) in production environment

Dinu, Berta; Fuchs, Stefan; Krämer, Uwe; Kubis, Michael; Marchelli, Anat; Navarra, Alessandra; Sparka, Christian; Widmann, Amir

doi:10.1117/12.771581

Cited by 5 publications

(4 citation statements)

References 1 publication

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“…To measure more grating parameters and nanometer-scale features on samples, this metrology technique uses rigorous electromagnetic calculation by coupled-wave approach [7,8,9,10,11,12] or modal approach [13,14,15,16,17,18] to compare it with the experimental diffraction pattern. The use of scatterometry for semiconductor metrology has been widely reported since the early 80's [19,20,21,22], even for specific overlay uses [23].…”

Section: Scatterometry First Steps…mentioning

confidence: 99%

S-Genius, a universal software platform with versatile inverse problem resolution for scatterometry

et al. 2013

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S-Genius is a new universal scatterometry platform, which gathers all the LTM-CNRS know-how regarding the rigorous electromagnetic computation and several inverse problem solver solutions. This software platform is built to be a userfriendly, light, swift, accurate, user-oriented scatterometry tool, compatible with any ellipsometric measurements to fit and any types of pattern. It aims to combine a set of inverse problem solver capabilities -via adapted LevenbergMarquard optimization, Kriging, Neural Network solutions -that greatly improve the reliability and the velocity of the solution determination. Furthermore, as the model solution is mainly vulnerable to materials optical properties, S-Genius may be coupled with an innovative material refractive indices determination. This paper will a little bit more focuses on the modified Levenberg-Marquardt optimization, one of the indirect method solver built up in parallel with the total SGenius software coding by yours truly. This modified Levenberg-Marquardt optimization corresponds to a Newton algorithm with an adapted damping parameter regarding the definition domains of the optimized parameters. Currently, S-Genius is technically ready for scientific collaboration, python-powered, multi-platform (windows/linux/macOS), multi-core, ready for 2D-(infinite features along the direction perpendicular to the incident plane), conical, and 3D-features computation, compatible with all kinds of input data from any possible ellipsometers (angle or wavelength resolved) or reflectometers, and widely used in our laboratory for resist trimming studies, etching features characterization (such as complex stack) or nano-imprint lithography measurements for instance. The work about kriging solver, neural network solver and material refractive indices determination is done (or about to) by other LTM members and about to be integrated on S-Genius platform.

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Section: Scatterometry First Steps…mentioning

confidence: 99%

S-Genius, a universal software platform with versatile inverse problem resolution for scatterometry

et al. 2013

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“…In productive environment, more pads should be employed to implement complex models so as to achieve more precise result and larger measurement range 6 . In Figure 7 a four-pad mark is presented, the corresponding signature is shown on the right, which can be more accurately described by a 4th order polynomial.…”

Section: Empirical Dbomentioning

confidence: 99%

Diffraction-based overlay measurement on dedicated mark using rigorous modeling method

et al. 2012

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Diffraction Based Overlay (DBO) is widely evaluated by numerous authors, results show DBO can provide better performance than Imaging Based Overlay (IBO). However, DBO has its own problems. As well known, Modeling based DBO (mDBO) faces challenges of low measurement sensitivity and crosstalk between various structure parameters, which may result in poor accuracy and precision. Meanwhile, main obstacle encountered by empirical DBO (eDBO) is that a few pads must be employed to gain sufficient information on overlay-induced diffraction signature variations, which consumes more wafer space and costs more measuring time. Also, eDBO may suffer from mark profile asymmetry caused by processes.In this paper, we propose an alternative DBO technology that employs a dedicated overlay mark and takes a rigorous modeling approach. This technology needs only two or three pads for each direction, which is economic and time saving. While overlay measurement error induced by mark profile asymmetry being reduced, this technology is expected to be as accurate and precise as scatterometry technologies.

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“…The other one is that SCOL technology detects the overlay information by differential diffraction signals, which is technically less sensitive to measurement focus accuracy. This focus robustness feature will be a great help for managing process variation within the wafer and tool-to-tool matching [1,2]. SCOL technology detects the diffraction signals from the grating-over-grating overlay target.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of overlay metrology accuracy by multi-wavelength scatterometry with rotated quadrupole illumination

Kim

Jeong

Hong

et al. 2023

Metrology, Inspection, and Process Control XXXVII

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As DRAM technology continues to evolve, advanced nodes shrink the device dimensions and raise the requirements for on-product overlay control to reduce residual error. Increased process complexity also demands tighter accuracy and robustness in metrology control, which necessitates new and innovative metrology enhancements and methods. Scatterometry-based overlay (SCOL®) metrology is a unique overlay metrology architecture that uses angle-resolved pupil imaging for overlay analysis and calculation. KLA’s SCOL metrology system offers wide-spectrum tunable laser and multi-wavelength (MWL) illumination patterns along with custom-designed advanced algorithms that provide multiple measurement conditions to meet unique layer and target requirements. This paper demonstrates improved overlay metrology accuracy and residual error on DRAM FEOL critical layer with SCOL technology. Multiwavelength and rotated quadrupole (RQ) illumination in the metrology tool are utilized to provide significantly improved residuals compared with the traditional single-wavelength (SWL) and on-axis illumination.

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Overlay control using scatterometry based metrology (SCOM) in production environment

Cited by 5 publications

References 1 publication

S-Genius, a universal software platform with versatile inverse problem resolution for scatterometry

S-Genius, a universal software platform with versatile inverse problem resolution for scatterometry

Diffraction-based overlay measurement on dedicated mark using rigorous modeling method

Enhancement of overlay metrology accuracy by multi-wavelength scatterometry with rotated quadrupole illumination

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