CD reference features with sub-five nanometer uncertainty

Cresswell, Michael W.; Dixson, R.; Guthrie, William F.; Allen, Richard A.; Murabito, Christine E.; Park, B.; Pinillos, Joaquin V Martinez de; Hunt, A.

doi:10.1117/12.606807

Cited by 9 publications

(15 citation statements)

References 9 publications

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“…As a result of the NIST SCCDRM project, it is possible to calibrate the zeroth order tip width with approximately a 1 nm standard uncertainty. 5,[11][12][13] The finer details of the tip-sample interaction, pertaining to things like flare radius, offset height, feature sidewall angle, feature corner radius, and the three-dimensional nature of both the tip and sample (i.e., shape in the axis perpendicular to the scan direction) are thought of as being higher-order tip effects. 5 Because these effects have a strong dependence on the specific geometry of each tip and feature, it is difficult to make general statements about the resulting uncertainties, and it is necessary to make a specific assessment for every measurement.…”

Section: The Nist Cd-afmmentioning

confidence: 99%

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Traceable atomic force microscope dimensional metrology at NIST

Dixson

Orji

et al. 2006

SPIE Proceedings

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The National Institute of Standards and Technology (NIST) has a multifaceted program in atomic force microscope (AFM) dimensional metrology. There are two major instruments being used for traceable AFM measurements at NIST. The first is a custom in-house metrology AFM, called the calibrated AFM (C-AFM), and the second instrument is a commercial critical dimension AFM (CD-AFM). The C-AFM has displacement metrology for all three axes traceable to the 633 nm wavelength of the Iodine-stabilized He-Ne laser. In the current generation of this system, the relative standard uncertainty of pitch and step height measurements is approximately 1.0 ×10 -3 for pitches at the micrometer scale and step heights at the 100 nm scale, as supported by several international comparisons. We expect to surpass this performance level soon. Since the CD-AFM has the capability of measuring vertical sidewalls, it complements the C-AFM. Although it does not have intrinsic traceability, it can be calibrated using standards measured on other instruments -such as the C-AFM, and we have developed uncertainty budgets for pitch, height, and linewidth measurements using this instrument. We use the CD-AFM primarily for linewidth measurements of near-vertical structures. At present, the relative standard uncertainties are approximately 0.2 % for pitch measurements and 0.4 % for step height measurements. As a result of the NIST single crystal critical dimension reference material (SCCDRM) project, it is possible to calibrate CD-AFM tip width with a 1 nm standard uncertainty. We are now using the CD-AFM to support the next generation of the SCCDRM project. In prototypes, we have observed features with widths as low as 20 nm and having uniformity at the 1 nm level.

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Section: The Nist Cd-afmmentioning

confidence: 99%

“…As a result of the NIST single crystal critical dimension reference material (SCCDRM) project, it is possible to calibrate CD-AFM tip width with a 1 nm standard uncertainty. 5,[11][12][13] And we are now using the SXM320 to support the next generation of the SCCDRM project, which may lead to even lower uncertainties.…”

Section: Introductionmentioning

confidence: 98%

Traceable atomic force microscope dimensional metrology at NIST

Dixson

Orji

et al. 2006

SPIE Proceedings

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“…These overall results of the project are being described elsewhere. 9 Therefore, the rest of this discussion will focus on the AFM methodology that was used, and the application of the SCCDRM samples to AFM linewidth metrology.…”

Section: Application Of the Cd-afm Rms To The Sccdrm Projectmentioning

confidence: 99%

“…The details of our analysis are being reported elsewhere. 9 The HRTEM fringes were counted manually and the images were analyzed in detail. Based upon this analysis, we concluded that most potential biases pertaining to sample preparation (e.g., surface effects, membrane distortion, FIB-induced damage) were not a concern.…”

Section: Traceability and Validating Metrologymentioning

confidence: 99%

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CD-AFM reference metrology at NIST and SEMATECH

et al. 2005

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The National Institute of Standards and Technology (NIST) and SEMATECH have been working together to improve the traceability of critical dimension atomic force microscope (CD-AFM) dimensional metrology in semiconductor manufacturing. A major component of this collaboration has been the implementation of a Reference Measurement System (RMS) at SEMATECH using a current generation CD-AFM. An earlier tool, originally used at SEMATECH, has now been installed at NIST. Uncertainty budgets were developed for pitch, height, and CD measurements using both tools. At present, the standard uncertainties are approximately 0.2 % for pitch measurements and 0.4 % for step height measurements. Prior to the current work, CD-AFM linewidth measurements were limited to a standard uncertainty of about 5 nm. However, this limit can now be significantly reduced. This reduction results from the completion of the NIST/SEMATECH collaboration on the development of single crystal critical dimension reference materials (SCDDRM). A new generation of these reference materials was released to SEMATECH Member Companies during late 2004. The SEMATECH RMS was used to measure the linewidths of selected features on the distributed specimens. To reduce the uncertainty in tip width calibration, a separate transfer experiment was performed in which samples were measured by CD-AFM and then sent for high resolution transmission electron microscopy (HRTEM). In this manner, CD-AFM could be used to transfer the HRTEM width information to the distributed samples. Consequently, we are now able to reduce the limit on the standard uncertainty (k = 1) of CD-AFM width measurements to 1 nm.

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