The role of AFM in semiconductor technology development: the 65 nm technology node and beyond

Ukraintsev, Vladimir A.; Baum, Christopher C.; Zhang, Gary; Hall, Craig

doi:10.1117/12.602758

Cited by 23 publications

(24 citation statements)

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“…Once sample-to-sample bias variation becomes comparable with precision, the classical approach underestimates the measurement uncertainty and incorrectly describes the CD metrology capability. With sample-to-sample bias variation of OS and SEM about 2 to 3 nm [3] the problem becomes noticeable at CD of ~100 nm. Therefore, the classical approach deficiency was first observed in gate CD metrology during the 130 nm technology development, but spread to other process levels in the course of the 90 and 65 nm nodes development.…”

Section: Figure 1 Relations Between Components Of Tmumentioning

confidence: 97%

“…Therefore, the classical approach deficiency was first observed in gate CD metrology during the 130 nm technology development, but spread to other process levels in the course of the 90 and 65 nm nodes development. Merits and weaknesses of CD OS and SEM have been discussed in many publications including [3,4]. These two complementary and competing techniques are at the core of modern CD metrology.…”

Section: Figure 1 Relations Between Components Of Tmumentioning

confidence: 98%

“…CD SEM is still widely used for various engineering tasks and remains the main metrology for optical proximity correction (OPC) modeling. Sample-to-sample bias variation of CD SEM is understood and documented [3,5,6]. Much less is known about TMU of OS [3,4,7,8].…”

Section: Figure 1 Relations Between Components Of Tmumentioning

confidence: 98%

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A comprehensive test of optical scatterometry readiness for 65-nm technology production

Ukraintsev

2006

SPIE Proceedings

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Measurement bias is a central concept of critical dimension (CD) metrology. Bias is a complex function of sample, tool and time. Bias variation defines the total measurement uncertainty (TMU). TMU is a measure of metrology quality. Precision (or bias variation with time) is only a part of TMU. Often tool-to-tool and sample-to-sample components of bias variation exceed precision. To measure sample-to-sample bias variation, knowledge of the reference CD value for the samples is required. Since bias is sample specific, the technology representative set of calibrated samples has to be created. The described approach has been implemented for a comprehensive evaluation of optical scatterometry (OS) to determine readiness of OS for the 65 nm technology production. The tests covered nine OS applications representative of the technology. The testing revealed that OS metrology is mostly ready to support 65 nm technology production. Both spectral ellipsometry and angular reflectometry OS compete closely on all applications. OS demonstrates acceptable averaged bias for CD and sidewall angle for most applications. Correlation of OS to other metrologies is usually satisfactory. At the same time some problems have been observed. The majority of the tested applications show poor linearity for some measured parameters. Cross-correlation between parameters is usually the cause. OS has trouble to meet the semiconductor industry's tight fleet precision requirements. For all applications, OS tool matching is a major component of fleet precision. The evaluation also exposed some general CD metrology challenges. With accuracy allowance in a sub-nanometer range, it is difficult to find an adequate reference technique to verify and calibrate OS models. Atomic force microscopy (AFM) has been chosen as a reference technique during this evaluation, but it has limitations. Precision, sidewall profile resolution and tip finite dimensions are some of the AFM limitations. OS fleet TMU for many applications is unacceptably high. Further work is needed to better understand the impact of reference data uncertainty on these alarming results. It is clear that to achieve a desired sub-nanometer agreement between reference and OS data, one must pay scrupulous attention to every detail of the experiment.

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Section: Figure 1 Relations Between Components Of Tmumentioning

confidence: 97%

Section: Figure 1 Relations Between Components Of Tmumentioning

confidence: 98%

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A comprehensive test of optical scatterometry readiness for 65-nm technology production

Ukraintsev

2006

SPIE Proceedings

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“…STI step height was evaluated based on layer thickness after each process step. Measured STI step height was confirmed to be accurate using atomic force microscopy (AFM) [25], [26].…”

Section: Gate Length Prediction Modelmentioning

confidence: 99%

Gate CD Control Considering Variation of Gate and STI Structure

Kurihara

Tanaka

Izawa

et al. 2007

IEEE Trans. Semicond. Manufact.

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We developed a fab-wide advanced process control system to control the critical dimension (CD) of gate electrode length in semiconductors. We also developed a model equation that predicts the gate CD by considering the structures of gate electrode and shallow trench isolation. This prediction model was also used to perform a factor analysis of gate CD variation. The effectiveness of the model in controlling feedforward was evaluated by both simulation and experiment. The CD variation of the wafers was improved from 8.9 nm in its 3 sigma without control to 3.5 nm with lot-to-lot feedforward control.

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“…The main application is the determination or verification of the critical dimensions, with the line width of the produced gratings in the first place. However, optical methods are usually calibrated and their accuracy is evaluated by comparison with other independent methods, such as state-of-the-art scanning electron microscopy (SEM) and atomic force microscopy (AFM), which provide adequate information about the detailed profiles of the grating lines [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Profile characterization of diffraction gratings using angle-resolved polarimetric measurements

Martino

Licitra

Foucher

et al. 2010

EPJ Web of Conferences

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Abstract. Development of the characterization tools and techniques used by semi-conductor industry directs not only towards increasing of the instrumental precision, to push limits of the optical characterization methods to the smallest lines, but also towards a decreased dependency of the used tools on the tool-to-tool calibration procedures. The challenge approached in this work is to use multiple independent optical configurations to determine overall accuracy of the results with minimal or no assistance of the other non-optical methods. The approach presented here is based on a well-known change of sensitivity of the optical model parameters at the different azimuthal measurement configurations. The full potential of this method can only be unlocked using complete Mueller matrix measurements providing complete information on the anisotropic nature of the gratings. The measurements at multiple azimuth configurations, used in this work, illustrate the potential of the method on the experimental data provided by the angle-resolved and spectrally resolved Mueller matrix polarimetric tools. The results are consistent with the single-line AFM measurements used as an independent reference.

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The role of AFM in semiconductor technology development: the 65 nm technology node and beyond

Cited by 23 publications

References 0 publications

A comprehensive test of optical scatterometry readiness for 65-nm technology production

A comprehensive test of optical scatterometry readiness for 65-nm technology production

Gate CD Control Considering Variation of Gate and STI Structure

Profile characterization of diffraction gratings using angle-resolved polarimetric measurements

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