A comprehensive comparison of spectral scatterometry hardware

Lensing, Kevin; Stirton, Broc; Starnes, Brian; Synoradzki, Joseph; Swain, Bryan; Lane, Lawrence

doi:10.1117/12.600783

Cited by 5 publications

(3 citation statements)

References 1 publication

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“…To that end, scatterometry metrology is being used rather than scanning electron microscopy (SEM). The top-down nature of CD-SEM renders it incapable of producing accurate sidewall information, especially at current geometries where critical resist lines are often densely nested and extremely vertical 11 . But while scatterometry solves the resist profile problem, it presents myriad challenges of its own.…”

Section: Scatterometry Metrologymentioning

confidence: 99%

Lithography process control using scatterometry metrology and semi-physical modeling

et al. 2007

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In this paper, results and analysis are presented from Advanced Micro Devices' (AMD) efforts at calculating lithography dose and focus parameters using scatterometry metrology and semi-physical CD models. The system takes advantage of the accurate and precise top and bottom CD data produced by scatterometry to differentiate dose and focus variation. To build the lithography process model, scatterometry data is generated for each field of a focus-exposure matrix (FEM) wafer, and the resulting top and bottom CD data is used to fit the parameters of series expansions relating CD to dose and focus. When new CD data is generated, the models can be inverted to solve for dose and focus independently. Our methodology employs a flexible modeling and inversion approach in an attempt to make the technique applicable to any production film stack and any line spacing regime. The quality of the inversion results are highly correlated to the degree of focus observability present in the system. Our results will show how a series of litho process with varied film stacks and line/space ratios respond to this technique, and we will report some best practices for a variety of use cases ranging from equipment characterization to focus monitoring on product.

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Section: Scatterometry Metrologymentioning

confidence: 99%

Lithography process control using scatterometry metrology and semi-physical modeling

et al. 2007

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“…Scatterometry has the significant benefits of fast, accurate, repeatable, and non-destructive measurement of the profile shape, critical dimension, and film thickness. Considerable research has been done on the scatterometry-based focus and exposure monitoring techniques [3][4][5][6][7]. The general method involves fitting a semi-physical model to the resist profile through scatterometry measurement of the CDs, side wall angle, and etc., then solves the inverse model to determine the exposure conditions.…”

Section: Introductionmentioning

confidence: 99%

Probe-pattern grating focus monitor through scatterometry calibration

2008

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This paper presents a new highly sensitive scatterometry based Probe-Pattern Grating (PPG) focus monitor and its printing assessment on an advanced exposure tool. The high sensitivity is achieved by placing transparent lines spaced at the strong focus spillover distance from the centerline of a 90 degree phase-shifted probe line that functions as an interferometer detector. The monitor translates the focus error into the probe line trench depth, which can be measured by scatterometry techniques. The sensitivity of the defocus measurement through scatterometry calibration is around 1.1nm defocus / nm trench depth. This result indicates that the PPG focus monitor from a single wafer focus setting can detect the defocus distance to well under 0.05 Rayleigh Units.

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“…Scatterometry has the significant benefits of fast, accurate, repeatable, and non-destructive measurement of the critical dimension, film thickness, and profile shape. Considerable research has been done on the scatterometry based focus and exposure monitoring techniques [3][4][5][6]. The general method involves using scatterometry to measure resist profile, and enabling independent solutions for dose and focus by fitting a semi-physical model to the data.…”

Section: Introductionmentioning

confidence: 99%

Parameter sensitive patterns for scatterometry monitoring

et al. 2007

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This paper proposes a new highly sensitive scatterometry based Probe-Pattern Grating Focus Monitor. The high sensitivity is achieved by placing transparent lines spaced at the strong focus spillover distance of around 0.6 /NA from the centerline of a 90 degree phase-shifted probe line that functions as an interferometer detector. The monitor translates the focus error into the probe line trench depth, which can be measured by scatterometry techniques. Simulations of optical imaging, resist development and Optical Digital Profilometry measurements are used to evaluate the expected practical performance. A linear model is developed to estimate focus error based on the measured probe trench depth.The results indicate that the ODP measurement from a single wafer focus setting can detect both the defocus direction and the defocus distance to well under 0.1 Rayleigh unit of defocus.

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A comprehensive comparison of spectral scatterometry hardware

Cited by 5 publications

References 1 publication

Lithography process control using scatterometry metrology and semi-physical modeling

Lithography process control using scatterometry metrology and semi-physical modeling

Probe-pattern grating focus monitor through scatterometry calibration

Parameter sensitive patterns for scatterometry monitoring

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