Traceable calibration of a critical dimension atomic force microscope

Dixson, Ronald G.; Orji, Ndubuisi G.; McGray, Craig D.; Bonevich, John E.; Geist, Jon

doi:10.1117/1.jmm.11.1.011006

Cited by 24 publications

(11 citation statements)

References 28 publications

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“…In topography mode, AFM is less sensitive to materials’ differences and as such could be used for low-contrast materials such as those shown in Figure 1d or in probing memristor nanodevices 67 where it has been used to study the shape dependent performance of ribbed and planar TiO 2 structures 119 . AFMs can be made directly traceable to the SI length using displacement interferometry, or with calibrated samples 120-122 . See Fig.…”

Section: Advanced Metrology Techniquesmentioning

confidence: 99%

Metrology for the next generation of semiconductor devices

Badaroglu²,

et al. 2018

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The semiconductor industry continues to produce ever smaller devices that are ever more complex in shape and contain ever more types of materials. The ultimate sizes and functionality of these new devices will be affected by fundamental and engineering limits such as heat dissipation, carrier mobility and fault tolerance thresholds. At present, it is unclear which are the best measurement methods needed to evaluate the nanometre-scale features of such devices and how the fundamental limits will affect the required metrology. Here, we review state-of-the-art dimensional metrology methods for integrated circuits, considering the advantages, limitations and potential improvements of the various approaches. We describe how integrated circuit device design and industry requirements will affect lithography options and consequently metrology requirements. We also discuss potentially powerful emerging technologies and highlight measurement problems that at present have no obvious solution.

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Section: Advanced Metrology Techniquesmentioning

confidence: 99%

Metrology for the next generation of semiconductor devices

Badaroglu²,

et al. 2018

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“…We measure the vertical dimensions of surface features with an atomic force microscope, which we calibrate with a submicrometer reference material with a step depth of 183.6 nm ± 0.9 nm that is NIST traceable. 21, 22 We report all uncertainties as a confidence interval of 95% or we note otherwise. A quartic polynomial linearizes the sensor response with negligible error, resulting in a systematic uncertainty of 0.5% for all depths.…”

Section: Resultsmentioning

confidence: 99%

Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles

et al. 2018

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The vertical dimensions of complex nanostructures determine the functions of diverse nanotechnologies. In this paper, we investigate the unknown limits of such structure-function relationships at subnanometer scales. We begin with a quantitative evaluation of measurement uncertainty from atomic force microscopy, which propagates through our investigation from ion beam fabrication to fluorescent particle characterization. We use a focused beam of gallium ions to subtractively pattern silicon surfaces, and silicon nitride and silicon dioxide films. Our study of material responses quantifies the atomic limits of forming complex topographies with subnanometer resolution of vertical features over a wide range of vertical and lateral dimensions. Our results demonstrate the underutilized capability of this standard system for rapid prototyping of subnanometer structures in hard materials. We directly apply this unprecedented dimensional control to fabricate nanofluidic devices for the analytical separation of colloidal nanoparticles by size exclusion. Optical microscopy of single nanoparticles within such reference materials establishes a subnanometer limit of the fluidic manipulation of particulate matter and enables critical-dimension particle tracking with subnanometer accuracy. After calibrating for optical interference within our multifunctional devices, which also enables device metrology and integrated spectroscopy, we reveal an unexpected relationship between nanoparticle size and emission intensity for common fluorescent probes. Emission intensity increases supervolumetrically with nanoparticle diameter and then decreases as nanoparticles with different diameters photobleach to similar values of terminal intensity. We propose a simple model to empirically interpret these surprising results. Our investigation enables new control and study of structure-function relationships at subnanometer scales.

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“…One of the major goals of this effort has been the application of CD-AFMs as reference measurement systems for traceable dimensional metrology. 35–37 The measurements described in this paper were primarily obtained on two CD-AFMs: (1) CD-AFM1 35 operates using a displacement measuring interferometer to detect the z -axis motion of the cantilever and (2) CD-AFM2 36 operates using a variation on the optical lever method to sense the cantilever motion. CD-AFM1 is thus capable of operating with lower vibration amplitudes than CD-AFM2.…”

Section: Measurements and Resultsmentioning

confidence: 99%

“…Subsequent to our initial efforts, some results were also obtained using CD-AFM3, a newer instrument that is installed at NIST. 37 CD-AFM3 has a more advanced tip control algorithm for scanning which can potentially reduce some imaging artifacts of CNT tips.…”

Section: Measurements and Resultsmentioning

confidence: 99%

Evaluation of carbon nanotube probes in critical dimension atomic force microscopes

Choi

Park

Ahn

et al. 2016

J. Micro/Nanolith. MEMS MOEMS

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The decreasing size of semiconductor features and the increasing structural complexity of advanced devices have placed continuously greater demands on manufacturing metrology, arising both from the measurement challenges of smaller feature sizes and the growing requirement to characterize structures in more than just a single critical dimension. For scanning electron microscopy, this has resulted in increasing sophistication of imaging models. For critical dimension atomic force microscopes (CD-AFMs), this has resulted in the need for smaller and more complex tips. Carbon nanotube (CNT) tips have thus been the focus of much interest and effort by a number of researchers. However, there have been significant issues surrounding both the manufacture and use of CNT tips. Specifically, the growth or attachment of CNTs to AFM cantilevers has been a challenge to the fabrication of CNT tips, and the flexibility and resultant bending artifacts have presented challenges to using CNT tips. The Korea Research Institute for Standards and Science (KRISS) has invested considerable effort in the controlled fabrication of CNT tips and is collaborating with the National Institute of Standards and Technology on the application of CNT tips for CD-AFM. Progress by KRISS on the precise control of CNT orientation, length, and end modification, using manipulation and focused ion beam processes, has allowed us to implement ball-capped CNT tips and bent CNT tips for CD-AFM. Using two different generations of CD-AFM instruments, we have evaluated these tip types by imaging a line/space grating and a programmed line edge roughness specimen. We concluded that these CNTs are capable of scanning the profiles of these structures, including re-entrant sidewalls, but there remain important challenges to address. These challenges include tighter control of tip geometry and careful optimization of scan parameters and algorithms for using CNT tips.

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Traceable calibration of a critical dimension atomic force microscope

Cited by 24 publications

References 28 publications

Metrology for the next generation of semiconductor devices

Metrology for the next generation of semiconductor devices

Subnanometer structure and function from ion beams through complex fluidics to fluorescent particles

Evaluation of carbon nanotube probes in critical dimension atomic force microscopes

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