Use of Monte Carlo models in the development and validation of CD operators

Frase, C. G.; Häßler-Grohne, Wolfgang

doi:10.1002/sia.2113

Cited by 21 publications

(21 citation statements)

References 8 publications

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“…about 10 nm for a probe diameter of 10 nm. Thus for the case of steep edges, a correction of the exponential top CD edge operator is required and was already published [16,17]. The trends in CD variation due to variation of model parameters which are presented here are confirmed by other Monte Carlo investigations for silicon structures and bottom CD evaluation [18].…”

Section: Top CD Uncertainty Evaluationsupporting

confidence: 80%

Calibration procedures and application of the PTB photomask CD standard

et al. 2005

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The PTB has developed a new 6025 photomask standard for calibration of CD metrology tools in a joint project with partners from mask industry in Germany [1]. We report on the design of the standard, its calibration procedures and the results of recent round robin measurements on this standard in which different CD metrology tools of the project partners were involved.The layout of the CD photomask standard (COG and 193 nm halftone PSM) contains isolated as well as dense features in both tones with nominal CD down to 100 nm. Calibration of the standards was performed at PTB by UV microscopy and LV-SEM, supported by additional AFM measurements for edge slope characterization. For analysis of UV microscopy as well as SEM images appropriate signal modeling was applied, which allowed to extract the feature widths at the top of the structures as well as the widths at 50% height of the structures.In this contribution we will also discuss results of a recent round robin comparison measurement performed on up-todate metrology tools available for CD metrology today by means of one of the newly developed CD standards. We used PTB calibrated CD standards in order to provide a set of CD references for the different tools which then should be used in a "blind" comparison to calibrate an unknown CD mask of the same design as the standards. Different type of CD metrology instrumentation, namely standard UV and DUV optical as well as DUV water immersion CD microscopes, a new UV dark field optical microscope, CD-SEM, and AFM/SFM were applied. The outcome of this comparison on currently applied metrology instrumentation provides a valuable source of information for cross calibration issues which are discussed in mask industry today.

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Section: Top CD Uncertainty Evaluationsupporting

confidence: 80%

Calibration procedures and application of the PTB photomask CD standard

et al. 2005

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“…When the electron beam is injected onto the sidewall of the specimen, the detected signal of the inner boundary has exponential distribution. 5 Although the peak of the signals broadens into a plateau and drops at slower speed as the angle of the sidewall decreases, it is evident that the intensity maximum occurs at the upper sidewall regardless of the angle of sidewall 6 (Fig. 3).…”

Section: Critical Dimensionmentioning

confidence: 90%

Measurement of critical dimension in scanning electron microscope mask images

Lee

Han

Jeong

2011

J. Micro/Nanolith. MEMS MOEMS

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In semiconductor industries, controlling and measuring critical dimensions are two important tools to design masks. However, measuring the dimensions with physical tools becomes more challenging, and the traditional method of measuring is slow and has many processes though it is accurate. This paper suggests a method that accurately measures the critical dimension length in a short time based on the digital image processing. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

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“…In the whole interaction volume, secondary electrons (SE) are generated. Monte Carlo simulations show that the lateral distribution of SE generation within the interaction volume can be well described by an exponential distribution, at least in low-voltage SEM [4]. Due to their low energy (typically 3-5 eV), only SE from a thin surface layer of a few nanometer can escape to vacuum.…”

Section: Sem Image Formation and Modelingmentioning

confidence: 97%

“…The choice of exponential functions is motivated by the lateral exponential distribution of the image intensity around the impinging electron beam in an SEM [4]. The model equation …”

Section: The Modelmentioning

confidence: 99%

A new SEM CD operator verified against Monte Carlo simulations

Frase

Gnieser

Dirscherl³

et al. 2007

SPIE Proceedings

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A new algorithm for SEM CD evaluation of trapezoidal line structures is presented. It is based on the physical modeling of SEM image formation and allows the assignment of top and bottom structural edge positions to the SEM signal. The SEM image profile is described by a set of piecewise continuous functions which is convoluted with the electron probe intensity profile. The resulting function is fitted to the measured signal profile by a least squares algorithm. The fit returns both top and bottom edge positions as well as the electron probe diameter. The algorithm is verified against three different Monte Carlo simulation programs using different physical models of elastic and inelastic electron scattering and secondary electron generation and transport. The effect of the physical modeling on the evaluated critical dimension is discussed and the absolute CD deviation of the algorithm is determined for different sets of specimen and tool parameters like edge slope angle, beam energy, and electron probe diameter.

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Use of Monte Carlo models in the development and validation of CD operators

Cited by 21 publications

References 8 publications

Calibration procedures and application of the PTB photomask CD standard

Calibration procedures and application of the PTB photomask CD standard

Measurement of critical dimension in scanning electron microscope mask images

A new SEM CD operator verified against Monte Carlo simulations

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