Integrated scatterometry in high-volume manufacturing for polysilicon gate etch control

Sendelbach, Matthew; Muñoz, Ana; Bandy, K.; Prager, Dan; Funk, Merritt

doi:10.1117/12.659946

Cited by 22 publications

(7 citation statements)

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“…These two applications were run in production with integrated scatterometry metrology, allowing advanced process control and resulting in tighter CD uniformity crossvalidated by electrical device performance [7,8]. They are well studied and provide excellent vehicles for careful characterization of the Model Optimizer methodology.…”

Section: A Structuresmentioning

confidence: 99%

Improved scatterometry time to solution for leading-edge logic applications

Vaid

Sendelbach

Komarov³

et al. 2010

2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference (ASMC)

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This paper describes an innovative approach to scatterometry modeling, significantly reducing time to solution compared to the industry's current best practices. One of the drawbacks to traditional scatterometry measurement techniques is the time required to optimize the model, which includes material optical constant extraction, model build time, initial model optimization, and model testing. A novel methodology that includes both stability and self-consistent scatterometry accuracy prediction can achieve an order of magnitude gain in productivity over prior methods. This technique creates opportunities among semiconductor chip manufacturers for wider scatterometry adoption at advanced technology nodes, where scatterometry is often the only reliable non-destructive metrology for device structure dimensions. The reductions in cycle time and improvements in accuracy prediction are keys to the success of scatterometry as an enabler for advanced process control and monitoring. This paper presents results on a conventional poly gate litho and final inspection and on leading-edge high-k metal gate after-etch applications. Spectroscopic ellipsometry is used to collect spectra from the gratings on the wafers. Then scatterometry results are obtained using the new approach and via traditional industryaccepted procedures to compare time to solution. To confirm the validity of the results, reference metrology data are collected on a CDSEM and TEM and the total measurement uncertainty is evaluated.

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Section: A Structuresmentioning

confidence: 99%

Improved scatterometry time to solution for leading-edge logic applications

Vaid

Sendelbach

Komarov³

et al. 2010

2010 IEEE/SEMI Advanced Semiconductor Manufacturing Conference (ASMC)

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“…For more information on TMU analysis, the authors recommend several papers. 1,5,6,7 In this paper, TMU values are compared to those obtained using the 0 degree AZ angle method. Figure 19: HKMG CD correlation vs. CDSEM.…”

Section: Accuracymentioning

confidence: 99%

Use of multiple azimuthal angles to enable advanced scatterometry applications

et al. 2010

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The ability to extract critical parameters using scatterometry depends on the parameter sensitivity and correlation at different wavelengths. These, in turn, determine the key metrics: accuracy, precision, and tool-to-tool matching. Parameter sensitivity and correlation can vary drastically, depending on whether the oblique incident light beam is parallel (azimuth angle = 90 degrees), perpendicular (azimuth angle = 0 degrees), or at an intermediate angle to the measured structures. In this paper, we explore the use of both variable-and multiple-azimuth (AZ) (or multi-AZ) angle spectroscopic ellipsometry (SE) to optimize the measurement performance for different applications.The first example compares the sensitivity and results using SE at 0 and 90 degree AZ angles for a BEOL post-litho metal trench application. We observe up to a sixfold improvement in key metrics for critical parameters using 90 degree over 0 degree AZ angle spectra.The second example illustrates the benefits of a multiple-AZ angle approach to extract critical parameters for a twodimensional logic High-K Metal Gate (HKMG) structure. Typically, this approach simultaneously fits two sets of SE spectra collected from the same location on the wafer at different AZ angles with the same physical model. This helps both validate and decorrelate critical parameters, enabling robust measurements. Results show that, for this application, the measurement performance metrics for each critical parameter are improved in almost every case.

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“…(1) whereσ 2 Mandel is the total error (also called the Mandel variance),σ 2 TuT is the error associated with the TuT, andσ 2 RMS is the compilation of all other errors, most notably those errors associated with the RMS. Note that each term is in variance form.…”

Section: Overview Of Total Measurement Uncertainty Analysismentioning

confidence: 99%

Effect of measurement error budgets and hybrid metrology on qualification metrology sampling

Sendelbach

Sarig

Wakamoto

et al. 2014

J. Micro/Nanolith. MEMS MOEMS

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Until now, metrologists had no statistics-based method to determine the sampling needed for an experiment before the start that accuracy experiment. We show a solution to this problem called inverse total measurement uncertainty (TMU) analysis, by presenting statistically based equations that allow the user to estimate the needed sampling after providing appropriate inputs, allowing him to make important "risk versus reward" sampling, cost, and equipment decisions. Application examples using experimental data from scatterometry and critical dimension scanning electron microscope tools are used first to demonstrate how the inverse TMU analysis methodology can be used to make intelligent sampling decisions and then to reveal why low sampling can lead to unstable and misleading results. One model is developed that can help experimenters minimize sampling costs. A second cost model reveals the inadequacy of some current sampling practices-and the enormous costs associated with sampling that provides reasonable levels of certainty in the result. We introduce the strategies on how to manage and mitigate these costs and begin the discussion on how fabs are able to manufacture devices using minimal reference sampling when qualifying metrology steps. Finally, the relationship between inverse TMU analysis and hybrid metrology is explored. Sendelbach et al.: Effect of measurement error budgets and hybrid metrology. . . Downloaded From: http://nanolithography.spiedigitallibrary.org/ on 05/14/2015 Terms of Use: http://spiedl.org/terms

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Integrated scatterometry in high-volume manufacturing for polysilicon gate etch control

Cited by 22 publications

References 0 publications

Improved scatterometry time to solution for leading-edge logic applications

Improved scatterometry time to solution for leading-edge logic applications

Use of multiple azimuthal angles to enable advanced scatterometry applications

Effect of measurement error budgets and hybrid metrology on qualification metrology sampling

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