Search

Carbon nanotubes (CNTs) can be used as atomic force microscopy (AFM) tips for high-resolution scanning due to their small diameter, high aspect ratio and outstanding wear resistance. However, previous approaches for fabricating CNT probes are complex and poorly controlled. In this paper, we introduce a simple method to selectively fabricate a single CNT on an AFM tip by controlling the trigger threshold to adjust the amount of growth solution attached to the tip. The yield rate is over 93%. The resulting CNT probes are suitable in length, without the need for a subsequent cutting process. We used the CNT probe to scan the complex nanostructure with a high aspect ratio, thereby solving the long-lasting problem of mapping complex nanostructures.

We have designed a fully automated optical microscope running at high-speed and achieving a very high spatial resolution. In order to overcome the resolution limit of optical microscopes, it exploits the localized surface plasmon resonance phenomenon. The customized setup using a polarization analyzer, based on liquid crystals, produces no vibrations and it is capable of probing isolated nanoparticles. We tested its performance with an automated readout using a fine-grained nuclear emulsion sample exposed to 60 keV carbon ion beam and, for the first time, successfully reconstructed the directional information from ultra-short tracks produced by such low-energetic ions using a solid-state tracking detector.

This paper presents the results of experimental studies and digital methods for recording of holograms using spatial light modulators. The use of holographic interference methods for measuring nanoscale irregularities is described for the case of a nanostep (70 nm in height and 30 $$\mu$$ m in width). Examples are given of the method of increased sensitivity for nanostep measurements and the method of hooks using a digital technique. Correction of internal system distortions in the interferometer has been shown to be a workable method. The holographic interference methods with digital processing of holograms allows the sensitivity of interferograms to be increased without loss of basic information about the object and without increasing the measurement accuracy.

Nanomaterials are the subject of a range of biomedical, commercial, and environmental investigations involving measurements in living cells and tissues. Accurate quantification of nanomaterials, at the tissue, cell, and organelle levels, is often difficult, however, in part due to their inhomogeneity. Here, we propose a method that uses the diverse optical properties of a nanomaterial preparation in order to improve quantification at the single-cell and organelle level. We developed ‘hyperspectral counting’, which employs diffraction-limited imaging via hyperspectral microscopy of a diverse set of nanomaterial emitters, to estimate nanomaterial counts in live cells and sub-cellular structures. A mathematical model was developed, and Monte Carlo simulations were employed, to improve the accuracy of these estimates, enabling quantification with single-cell and single-endosome resolution. We applied this nanometrology technique to identify an upper-limit of the rate of uptake into cells - approximately 3,000 particles endocytosed within 30 minutes. In contrast, conventional ROI counting results in a 230% undercount. The method identified significant heterogeneity and a broad non-Gaussian distribution of carbon nanotube uptake within cells. For example, while a particular cell contained an average of 1 nanotube per endosome, the heterogenous distribution resulted in over 7 nanotubes localizing within some endosomes, substantially changing the accounting of subcellular nanoparticle concentration distributions. This work presents a method to quantify cellular and subcellular concentrations of a heterogeneous carbon nanotube reference material, with implications for nanotoxicology, drug/gene delivery, and nanosensor fields.

X-ray mirrors are widely used for synchrotron radiation, free-electron lasers, and astronomical telescopes. The short wavelength and grazing incidence impose strict limits on the permissible slope error. Advanced polishing techniques have already produced mirrors with slope errors below 50 nrad root mean square (rms), but existing metrology techniques struggle to measure them. Here, we describe a laser speckle angular measurement (SAM) approach to overcome such limitations. We also demonstrate that the angular precision of slope error measurements can be pushed down to 20nrad rms by utilizing an advanced sub-pixel tracking algorithm. Furthermore, SAM allows the measurement of mirrors in two dimensions with radii of curvature as low as a few hundred millimeters. Importantly, the instrument based on SAM is compact, low-cost, and easy to integrate with most other existing X-ray mirror metrology instruments, such as the long trace profiler (LTP) and nanometer optical metrology (NOM). The proposed nanometrology method represents an important milestone and potentially opens up new possibilities to develop next-generation super-polished X-ray mirrors, which will advance the development of X-ray nanoprobes, coherence preservation, and astronomical physics., A versatile high precision metrology instrument has been developed that surpass the limits of existing metrology techniques and opens up new possibilities to develop next-generation super-polished X-ray mirrors.

This paper presents the reduction in cross-talk errors in the angular outputs existing in the previously designed six-degree-of-freedom (DOF) surface encoder for nanopositioning and nanometrology. The six-DOF surface encoder is composed of a planar scale grating and an optical sensor head with a reference grating, a displacement assembly and an angle assembly. The diffracted beams from both the scale and the reference gratings are received by the displacement assembly for measurement of the primary XYZ translational motions. The angle assembly only receives the diffracted beams from the scale grating for measurement of the secondary θXθYθZ angular motions. In this paper, at first, the cross-talk errors in the angular measurement results of the previous surface encoder are identified to be caused by the diffracted beams from the reference grating leaking into the angle assembly due to the imperfection of the polarization components of the sensor head. An improved design of the sensor head is then carried out to reduce the cross-talk errors by changing the position of the angle assembly in the sensor head. The sensor head is further optimized by replacing the beam splitter located in front of the angle assembly from a cube type to a plate type. Experimental results have demonstrated that the cross-talk errors were reduced from 3.2 arc-seconds to 0.02 arc-second.

A fundamental understanding and advancement of nanopatterning and nanometrology are essential in the future development of nanotechnology, atomic scale manipulation, and quantum technology industries. Scanning probe-based patterning/imaging techniques have been attractive for many research groups to conduct their research in nanoscale device fabrication and nanotechnology mainly due to its cost-effective process; however, the current tip materials in these techniques suffer from poor durability, limited resolution, and relatively high fabrication costs. Here, we report on employing GaN nanowires as a robust semiconductor material in scanning probe lithography (SPL) and microscopy (SPM) with a relatively low-cost fabrication process and the capability to provide sub-10 nm lithography and atomic scale (

A comparative experimental study between advanced carbon nanostructured electrodes, in similar hydrogen uptake/desorption conditions, is investigated making use of the recent molecular beam-thermal desorption spectrometry. This technique is used for monitoring hydrogen uptake and release from different carbon electrocatalysts: 3D-graphene, single-walled carbon nanotube networks, multi-walled carbon nanotube networks, and carbon nanotube thread. It allows an accurate determination of the hydrogen mass absorbed in electrodes made from these materials, with significant enhancement in the signal-to-noise ratio for trace hydrogen avoiding recourse to ultra-high vacuum procedures. The hydrogen mass spectra account for the enhanced surface capability for hydrogen adsorption in the different types of electrode in similar uptake conditions, and confirm their enhanced hydrogen storage capacity, pointing to a great potential of carbon nanotube threads in replacing the heavier metals or metal alloys as hydrogen storage media. publishersversion published

Besides high-power light-emitting diodes (LEDs) with dimensions in the range of mm, micro-LEDs (μLEDs) are increasingly gaining interest today, motivated by the future applications of μLEDs in augmented reality displays or for nanometrology and sensor technology. A key aspect of this miniaturization is the influence of the structure size on the electrical and optical properties of μLEDs. Thus, in this article, investigations of the size dependence of the electro-optical properties of μLEDs, with diameters in the range of 20 to 0.65 μm, by current–voltage and electroluminescence measurements are described. The measurements indicated that with decreasing size leakage currents in the forward direction decrease. To take advantage of these benefits, the surface has to be treated properly, as otherwise sidewall damages induced by dry etching will impair the optical properties. A possible countermeasure is surface treatment with a potassium hydroxide based solution that can reduce such defects.

This paper seeks to demonstrate the efficacy of a new approach for fast, in-line, and direct topography measurement of nano-scale structures and features on a flexible substrate, or web, in a roll-to-roll fashion. Nanofeatured products manufactured with R2R processes can be extremely cost competitive compared to more traditional, wafer-based solutions in addition to their unique and desirable mechanical properties. As such they are an area of immense research interest. But, despite the promise of these products for a plethora of applications, the leap from lab-scale prototypes to pilot- or volumescale manufacturing has proven extraordinarily difficult and expensive — with both required research and development investment and achievable process yield proving sizable barriers. A key capability gap in current art and roadblock on the path towards more widespread research and adoption of these R2R fabricated products is the lack of high-throughput, nanometer-scale metrology for process development, control, and yield enhancement. In this work a new type of extremely compact, tip-based microscope designed and fabricated with a micro-electro-mechanical system approach is applied to the challenge of direct topography measurement for roll-to-roll fabricated nanopatterns. A proof-of-concept tool with subsystems to regulate the flexible web, isolate and position the atomic force microscope, and measure features on the substrate, all coordinated by a real-time embedded control system is shown and step-and-scan measurement results were acquired. However, to genuinely meet this extent need for roll-to-roll metrology, a system capable of atomic force microscope scanning despite a continuous, non-zero web velocity must be developed to meet throughput requirements without degrading measurement quality and thus help to enable the next generation of R2R nanomanufacturing technology.

One dimensional (1D) Cr nanograting fabricated by laser-focused atomic deposition (LFAD) is suitable for reference materials in nanometrology, owing to its self-traceable to SI meter definition and high accuracy with good uniformity. For further preparing small-scale and traceable reference materials, extremely ultraviolet (EUV) interference lithography with 13.4nm wavelength is utilized to accurately shorten the grating pitch of Cr nanograting (212.8nm). Diffraction efficiency is a key attribute in EUV interference lithography. In this paper, based on rigorous coupled wave analysis (RCWA), diffraction efficiency with EUV light of Cr nanograting was studied. Impacts such as EUV light wavelength, background layer and grating height were mainly taken into consideration. The result shows that Cr background layer has significant influence on diffraction efficiency of Cr nanograting, and an optimized diffraction efficiency of the first diffraction order about 1.4% has been achieved under the practical experimental condition.

Magnetic sensing is present in our everyday interactions with consumer electronics and demonstrates the potential for the measurement of extremely weak biomagnetic fields, such as those of the heart and brain. In this work, we leverage the many benefits of microelectromechanical system (MEMS) devices to fabricate a small, low-power, and inexpensive sensor whose resolution is in the range of biomagnetic fields. At present, biomagnetic fields are measured only by expensive mechanisms such as optical pumping and superconducting quantum interference devices (SQUIDs), suggesting a large opportunity for MEMS technology in this work. The prototype fabrication is achieved by assembling micro-objects, including a permanent micromagnet, onto a postrelease commercial MEMS accelerometer using a pick-and-place technique. With this system, we demonstrate a room-temperature MEMS magnetic gradiometer. In air, the sensor’s response is linear, with a resolution of 1.1 nT cm−1, spans over 3 decades of dynamic range to 4.6 µT cm−1, and is capable of off-resonance measurements at low frequencies. In a 1 mTorr vacuum with 20 dB magnetic shielding, the sensor achieves a 100 pT cm−1 resolution at resonance. This resolution represents a 30-fold improvement compared with that of MEMS magnetometer technology and a 1000-fold improvement compared with that of MEMS gradiometer technology. The sensor is capable of a small spatial resolution with a magnetic sensing element of 0.25 mm along its sensitive axis, a >4-fold improvement compared with that of MEMS gradiometer technology. The calculated noise floor of this platform is 110 fT cm−1 Hz−1/2, and thus, these devices hold promise for both magnetocardiography (MCG) and magnetoencephalography (MEG) applications. A small, low-power, inexpensive magnetic sensor has been developed in a commercially available platform with a resolution that is within the range of biomagnetic fields. Magnetic sensing is applied in everyday interactions with consumer electronics (such as for navigation) and has the potential to measure extremely weak biomagnetic fields (such as those of the heart and brain). Hitherto, biomagnetic fields have been measured only using expensive mechanisms. However, a team headed by Josh Javor at Boston University, USA has succeeded in applying the benefits of micro-electromechanical systems to fabricate a low-cost magnetic sensor in a small, versatile platform that can be easily integrated into consumer technology. We believe that their new technology has the potential to revolutionize magnetic sensing and offer considerable advantages in such areas as navigation, communication, and biomagnetic field mapping.

Laser-driven light sources (LDLS) have ultrahigh-brightness and broad wavelength range. They are ideal radiation sources for optical metrology tools for advanced process control in semiconductor manufacturing. LDLS sources, with their advantages of 170 nm to 2100 nm wavelength range, have been widely adopted and are being used in volume manufacturing for spectroscopic ellipsometry (SE), spectroscopic scatterometry (SS), and white light interferometry (WLI) applications. Such applications are used to measure critical dimensions (CD), overlay (OVL), and film thickness.

Scanning probe microscopy (SPM) techniques are amongst the most important and versatile experimental methods in surface- and nanoscience. Although their measurement principles on rigid surfaces are well understood and steady progress on the instrumentation has been made, SPM imaging on suspended, flexible membranes remains difficult to interpret. Due to the interaction between the SPM tip and the flexible membrane, morphological changes caused by the tip can lead to deformations of the membrane during scanning and hence significantly influence measurement results. On the other hand, gaining control over such modifications can allow to explore unknown physical properties and functionalities of such membranes. Here, we demonstrate new types of measurements that become possible with two SPM instruments (atomic force microscopy, AFM, and scanning tunneling microscopy, STM) that are situated on opposite sides of a suspended two-dimensional (2D) material membrane and thus allow to bring both SPM tips arbitrarily close to each other. One of the probes is held stationary on one point of the membrane, within the scan area of the other probe, while the other probe is scanned. This way new imaging modes can be obtained by recording a signal on the stationary probe as a function of the position of the other tip. The first example, which we term electrical cross-talk imaging (ECT), shows the possibility of performing electrical measurements across the membrane, potentially in combination with control over the forces applied to the membrane. Using ECT, we measure the deformation of the 2D membrane around the indentation from the AFM tip. In the second example, which we term mechanical cross-talk imaging (MCT), we disentangle the mechanical influence of a scanning probe tip (e.g. AFM) on a freestanding membrane by means of independently recording the response of the opposing tip. In this way we are able to separate the tip-induced membrane deformation topography from the (material-dependent) force between the tip and the membrane. Overall, the results indicate that probing simultaneously both surfaces of ultra-thin membranes, such as suspended 2D materials, could provide novel insights into the electronic properties of the materials.

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.

An atomic force microscopy (AFM) scanning head is designed with the probe orthogonal scanning mode for metrological AFM to eliminate the curvature distortion. The AFM probe is driven by piezostage and the scanning trajectory of the probe in 3 directions are orthogonal to reduce the cross coupling. A new optical lever amplification optical path is developed to eliminate the coupling error. The tracing lens and probe tip are moved as an integrated part. The AFM is operated at contacting mode. The step approach process of the probe tip is tested to the sample surface and the noise of the AFM head is analyzed. The response of the probe demonstrates a 0.5 nm resolution of the probe head in the z direction. Finally, the planar scanning performance of the scanning head is demonstrated compared with tube scanning AFM.

Spectrometry is widely used for the characterization of materials, tissues, and gases, and the need for size and cost scaling is driving the development of mini and microspectrometers. While nanophotonic devices provide narrowband filtering that can be used for spectrometry, their practical application has been hampered by the difficulty of integrating tuning and read-out structures. Here, a nano-opto-electro-mechanical system is presented where the three functionalities of transduction, actuation, and detection are integrated, resulting in a high-resolution spectrometer with a micrometer-scale footprint. The system consists of an electromechanically tunable double-membrane photonic crystal cavity with an integrated quantum dot photodiode. Using this structure, we demonstrate a resonance modulation spectroscopy technique that provides subpicometer wavelength resolution. We show its application in the measurement of narrow gas absorption lines and in the interrogation of fiber Bragg gratings. We also explore its operation as displacement-to-photocurrent transducer, demonstrating optomechanical displacement sensing with integrated photocurrent read-out., Fully integratable spectrometers have trade-offs between size and resolution. Here, the authors present a nano-opto-electro-mechanical system where the functionalities of transduction, actuation and detection are fully integrated, resulting in an ultra-compact high-resolution spectrometer with a micrometer-scale footprint.

Graphene on copper foil produced through chemical vapor deposition has been transferred to different substrates and the Raman signatures from graphene on semi-insulating GaAs, n-GaAs, SiO2 (300 nm)/Si, boron-doped Si, phosphorus-doped Si have been studied. It is found that all the material varieties, morphology and lattice of substrates can influence the Raman scattering spectra from graphene. The obtained results are important for nanometrology of graphene and graphene based devices.

Surface patterning technologies represent a worldwide growing industry, creating smart surfaces and micro/nanoscale device. The advent of large-area, high-speed imprinting technologies has created an ever-growing need for rapid and non-destructive dimensional metrology techniques to keep pace with the speed of production. Here we present a new real-time optical scatterometry technique, applicable at the mesoscale when optical inspection produces multiple orders of diffraction. We validate this method by inspecting multiple silicon gratings with a variety of structural parameters. These measurements are cross-referenced with FIB, SEM and scanning stylus profilometry. Finally, we measure thermally imprinted structures as a function of imprinting temperature in order to demonstrate the method suitable for in-line quality control in nanoimprint lithography., The authors acknowledge the financial support from the EU project, FLEXPOL (No. H2020-NMBP-PILOT-2016-721062) and the project: Surface and interface reshaped phonon propagation and phonon coupling to photons (SIP). PGC2018-101743-B-I00 (MINECO). The ICN2 is funded by the CERCA programme/Generalitat de Catalunya and is supported by the Severo Ochoa programme of the Spanish Ministry of Economy, Industry and Competitiveness (MINECO, grant no. SEV-2017-0706).

As the modern technology becomes increasingly nanoscale, microscopy and metrology methods relying on visible and UV wavelengths can no longer fully satisfy scientific and industrial needs. Reduction of the working wavelength to the extreme ultraviolet (EUV, 5 to 50 nm) region is a promising way to extend the applicability of optical techniques to cutting-edge nanotechnology. Short wavelengths and efficient interaction of EUV radiation with matter provides spatial and depth resolution on the nanoscale, which enables not only ultra-high-resolution lithography, but also microscopy, high-precision thin film analysis and dimensional metrology of nanostructures. The presentation is focusing on laboratory-based applications of EUV radiation enabled by compact plasma-based EUV radiation sources. The topics of nanoscale imaging, defect detection, thin film analysis and critical dimensions metrology will be discussed. The developed laboratory tools, such as multi-angle spectroscopic EUV reflectometer and EUV dark-field microscope, will be presented together with latest obtained experimental results. Thin film analysis with sub-nm precision will be demonstrated and benchmarked against state-of-the-art X-ray reflectometry. Specific modelling challenges in the EUV region will be outlined and possible solutions and opportunities will be presented. At the end general limits of applicability of the EUV radiation for industrial and scientific metrology will be discussed together with an outlook to potential perspectives of the EUV-based optical metrology.

The microwave properties of nano-scale structures are important in a wide variety of applications in quantum technology. Here we describe a low-power cryogenic near-field scanning microwave microscope (NSMM) which maintains nano-scale dielectric contrast down to the single microwave photon regime, up to 109 times lower power than in typical NSMMs. We discuss the remaining challenges towards developing nano-scale NSMM for quantum coherent interaction with two-level systems as an enabling tool for the development of quantum technologies in the microwave regime.

Using light as a probe to investigate perturbations with deep subwavelength dimensions in large-scale wafers is challenging because of the diffraction limit and the weak Rayleigh scattering. In this Letter, we report on a nondestructive noninterference far-field imaging method, which is built upon electrodynamic principles (mechanical work and force) of the light-matter interaction, rather than the intrinsic properties of light. We demonstrate sensing of nanoscale perturbations with sub-10 nm features in semiconductor nanopatterns. This framework is implemented using a visible-light bright-field microscope with a broadband source and a through-focus scanning apparatus. This work creates a new paradigm for exploring light-matter interactions at the nanoscale using microscopy that can potentially be extended to many other problems, for example, bioimaging, material analysis, and nanometrology.

Modern integrated circuit (IC) packaging faces challenges for higher speed in a smaller dimension achieved due to the 10 nm or smaller process node. While ICs are being packaged in 3D format, it is often not possible to measure features and/or defects in a non-destructive route. This paper reports a technique for nanometrology using bigger wavelengths such as those within the terahertz range. Practical measurements of dot pattern and other patterns on a 3D chip under the surface have been carried out. Two graphene have been imaged for quantifying the number of layers in the exfoliate also the thickness of each graphene sheet in the exfoliate. The results check out well compared to the standard techniques such as the SEM. In addition, a criterion for graphene’s quality assessment in terms of direct measurement of number of sheets in an exfoliate has been proposed. Thus, the nanometrology reported here, is a versatile tool for nanoscale measurements.

Alternative lithography approaches, especially pattering technologies are in advance since several years. Every day new, more or less high localized, AFM-tip based structuring methods as well as new optical and e-beam methods become acquainted. Most of them are sequential single-point procedures. The local interaction reaches from 150 nm up to sub-10 nm. Especially tip based methods are developed on the basis of atomic force microscopes AFM. Therefore, the ranges, which can be structured, are only in the range of 2 µm x 2 µm up to 100 µm x 100 µm. In most cases it is not known or not verified if those new tip based techniques are suitable for larger ranges and areas. Even the stages and control algorithms of AFM’s are not optimized for defined, high dynamic and as well high stable scanning trajectories in the nanometre respectively in the sub-nanometre level. Here, Prof. Tseng from Arizona State University noted “the quality…of the nanostructures created by TipBased Nanofabrication depend greatly on the capacities of equipment and instruments used and the extent to which the tip can be precisely controlled. It is unavoidable that the TBN system be automated and that precision of control be in the subnanometers for dimension accuracy, and sub-nanonewtons for force accuracy.” [1] A first way out to increase the precision could be the application of so-called metrological AFM, especially developed at national metrological institutes. But the deficit of a small scanning range still remains. Nanopositioning and nanomeasuring machines where developed at the Technische Universitat Ilmenau, Institute of Process Measurement and Sensor technology, first for positioning and measuring three-dimensional objects in a range of 25 mm x 25 mm x 5 mm with 20 pm resolution and nanometer precision [12]. They can equipped with most versatile probing systems like AFM, laser focus probes and 3D-micro probes to fulfill extraordinary metrological challenges. This unique precision is allowed by the application of an extended three-dimensional Abbe-comparator principle combined with high precision laser interferometer controlled stage in six degrees of freedom. A substantial progress in nano patterning can be achieved by combining this outstanding technology with advanced scanning proximal probe lithography on the base of Fowler-Nordheim-electron-field emission [30]. In this NPMmachine the high precision large area pattern generation can be combined with an advanced high speed nanometrology simultaneously. This paper addresses different aspects that are related to the metrological challenges in increasing measuring volumes up to 200 mm x 200 mm x 25 mm, high dynamic nanopositioning and control on complex trajectories, as well as implementation of nanofabrication tools into the NPMM-machine.

Calibration of magnification and nonlinearity of scanning electron microscopy (SEM) is an essential task. In this paper, we proposed a new type of 1D grating sample fabricated by combining laser-focused atomic deposition and x-ray interference lithography as a lateral standard for calibrating SEMs. The calibrations of the grating pattern by a metrological large-range atomic force microscope indicate that the grating sample exhibits outstanding pattern uniformity that surpasses conventional samples fabricated by e-beam lithography: (1) the nonlinear deviation of the grating structures is below +/- 0.5 nm over a measurement range of 5 µm; (2) the maximal variation of the calibrated mean pitch values is lower than 0.01 nm at different locations randomly selected all over the pattern area. The proposed new sample is applied for accurately calibrating the magnification and nonlinearity of a commercial SEM, showing its advantages of easy-of-use and high accuracy. The influence of the defocus level of SEM on the calibration result is also demonstrated. This research offers a feasible solution for highly accurate SEM calibration needed for 3D nanometrology and hybrid metrology demanded in metrology of modern nanoelectronics devices and systems.

Atomic force microscopy enables three-dimensional high-resolution imaging of surfaces with nanoscale features. In order to obtain the quantitative information about surface geometry, the atomic force microscope’s scanning system must be calibrated. This is usually done by using calibration samples of known and/or defined shape based on either lithographic or crystal structures. In this work we report on a microelectromechanical device, referred to as a displacement generator, whose vertical deflection is controlled electronically. The designed, fabricated and applied device is formed out of a silicon nitride doubly clamped lever, referred to as a microbridge, with a deposited pair of platinum strips. When the MEMS displacement generator is immersed in a magnetic field and when it is electrically biased, the associated Lorentz force induces a structural displacement. In the presented design, the silicon nitride microbridges were fabricated on a (110) silicon wafer in a Wheatstone bridge configuration. A second reference cantilever was mechanically supported by the silicon substrate. In this way, a highly symmetrical structure was fabricated, making it possible to control precisely deflection in Z direction with sub-nanometre precision. The cantilever’s high resonance frequency, of ca. 500 kHz, makes the constructed device insensitive to external vibration sources which are typically at much lower frequencies. As the stage function can be described using the simple harmonic oscillator model, it is clear that the system can operate with sub-nanometre resolution, which, for the purpose of microscope calibration, is extremely beneficial. By placing of the atomic force microscope tip on the actuated reference device it is possible to determine the response of the system over a wide frequency bandwidth. In this work we will describe the fabrication process of the MEMS displacement generator, interferometric and traceable investigations of thermomechanical and electromagnetic actuation schemes. Moreover, we will present the results of the calibration of an atomic force microscope operating in contact and intermittent contact modes.

We propose a wavelength standard for highly precise dimensional measurements. An internal-mirror helium-neon laser is offset-locked to a frequency comb line in order to carry out a secondary standard with reduced phase noise and high optical power. Additional lasers can be traced back to this secondary standard, which will enable us to disseminate the accuracy and stability to the metrology lasers of our nanopositioning and -measuring machine, the so-called NPMM-200. First measurements revealed that the stability of the secondary standard is restricted by the time standard of the optical frequency comb to a value of 2.4·10-12 (τ = 1 s), which is a significant improvement in comparison to the stability of the existing metrology lasers. In further measurements a metrology laser was locked onto the secondary standard with a relative instability of 0.6·10-15 (τ = 1000 s).

Here we present a new unlabelled far field optical imaging technique using microspheres to enhance the lateral resolution in optical microscopy. Both 2D and 3D super-resolution imaging using microspheres are considered, providing results of 2D and 3D imaging of surfaces with vastly improved lateral resolution and nanometric axial resolution for the 3D mode. Results are shown on narrow etched gratings in Si, nanotextured stainless steel surfaces and Ag nanodots.The main results demonstrate improvements of up to 3 times in lateral resolution, showing details of 300 nm for a microscope that would normally have a limit of 850 nm. Microsphere-assisted microscopy is a major new type of far field optical microscopy with great potential for high resolution imaging, characterisation and nanometrology in materials science and the biological sciences.

We present a partial application space of the metrology method referred to as through-focus scanning optical microscopy (TSOM), with most number of favorable attributes as a metrology and process control tool. TSOM is a NIST-developed, high-throughput and low-cost optical metrology tool for dimensional characterization with sub-nanometer measurement resolution of nano-scale to microscale targets using conventional optical microscopes, with many unique benefits and advantages. In TSOM the complete set of out-of-focus images are acquired using a conventional optical microscope and used for dimensional analysis. One of the unique characteristics of the TSOM method is its ability to reduce or eliminate optical cross correlations, often challenging for optical based metrology tools. TSOM usually has the ability to separate different dimensional differences (i.e., the ability to distinguish, for example, linewidth difference from line height difference) and hence it is expected to reduce measurement uncertainty. TSOM is applicable to a wide variety of target materials ranging from transparent to opaque, and shapes ranging from simple nanoparticles to complex semiconductor memory structures, including buried structures under transparent films. TSOM has been successfully applied to targets ranging from one nm to over 100 μm (over five orders or magnitude size range). Demonstrated applications of TSOM include critical dimension (linewidth), overlay, patterned defect detection and analysis, FinFETs, nanoparticles, photo-mask linewidth, thin-film (less than 0.5 nm to 10 nm) thickness, throughsilicon vias (TSVs), high-aspect-ratio (HAR) targets and others with several potential three-dimensional shape process monitoring applications such as MEMS/NEMS devices, micro/nanofluidic channels, flexible electronics, self-assembled nanostructures, and waveguides. Numerous industries could benefit from the TSOM method —such as the semiconductor industry, MEMS, NEMS, biotechnology, nanomanufacturing, nanometrology, data storage, and photonics.

A method is described intended for distributed calibration of a probe microscope scanner consisting in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be defined by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used to implement the distributed calibration, which permits to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. The sensitivity of LCCs to errors in determination of position coordinates of surface features forming the local calibration structure (LCS) is eliminated by performing multiple repeated measurements followed by building regression surfaces. There are no principle restrictions on the number of repeated LCS measurements. Possessing the calibration database enables correcting in one procedure all the spatial distortions caused by nonlinearity, nonorthogonality and spurious crosstalk couplings of the microscope scanner piezomanipulators. To provide high precision of spatial measurements in nanometer range, the calibration is carried out using natural standards - constants of crystal lattice. The method allows for automatic characterization of crystal surfaces. The method may be used with any scanning probe instrument., Comment: Preprint of research article, 15 pages, 3 figures

2011. godine uHrvatskom nacionalnom laboratorijuza duljinu (HMI/FSB-LPMD) razvijeni su etaloni za umjeravanje, a koji su izrađeni u suradnji s tvrtkom MikroMaschTrading OU i Institutom Ruđer Bošković. Specifični dizajn etalona čini ih prikladnim za umjeravanje optičkih mjernih uređaja, uređaja s ticalom, skenirajućih elektronskih mikroskopa, mikroskopa atomskih sila i skenirajućih tunelirajućih mikroskopa. Stoga razvijeni etaloni uvelike pridonose obnovljivosti rezultata mjerenja dubine brazde i 2D i 3D parametara hrapavosti dobivenih različitim mjernim metodama. Nakon niza provedenih mjerenja na novim etalonima, temeljem kojih su stečena nova znanja, u HMI/FSB-LPMD-u osmišljeni su novi etaloni za područje dimenzionalnog nanomjeriteljstva. U ovom radu predstavljen je dizajn novog etalona, koji je još uvijek prikladan za umjeravanje različitih tipova mjernih uređaja, ali ima veće mogućnost mjerenja u smislu mjernih raspona u vertikalnom i lateralnom smjeru., In 2011 Croatian National Laboratory for Length (HMI/FSB-LPMD) developed calibration standards which have been physically implemented in cooperation with the company MikroMasch Trading OU and the Ruđer Bošković Institute. Specific design of standards makes them suitable for calibration of optical instruments, stylus instruments, scanning electron microscopes, atomic force microscopes and scanning tunnelling microscopes. Therefore, the developed calibration standards greatly contribute to the reproducibility of measurement results for groove depth well as the 2D and 3D roughness parameters obtained by various measuring methods. After a number of measurements conducted on developed standards, based on which new knowledge was acquired, HMI/FSB-LPMD designed a new standard for the field of dimensional nanometrology. This paper presents the design of a new standard that is still suitable for calibration of different types of measuring instruments, i.e. methods, but has a larger measurement capability in terms of measuring ranges in vertical and lateral direction.

Light emitting diodes become brighter because of the contribution of patterned sapphire substrates (PSS). The dimensions of PSS crucially affect its performance. The most suitable instrument to measure PSS is atomic force microscope, which provides three-dimensional surface profiles. This paper proposes an automatic method to analyze AFM-collected raw data and produce characteristic parameters of PSS, including height, diameters, pitch, and side angles. Experimental results show that this method has good repeatability of 1.2 and 6.3 nm on measuring height and bottom diameter, respectively. This nanometrology method will be extensively applicable for similar nanostructures with periodic patterns.

Nano-hardness tester with three-coordinate laser heterodyne interferometer integrated in the commercially available industrial scanning probe is developed. It allows ensuring traceability of measurements in nanometer range to the primary standard of meter. This device may be used for the characterization of indentor's tips. Corresponding method is presented.

Through-focus scanning optical microscopy (TSOM) shows promise for patterned defect analysis, but it is important to minimize total system noise. TSOM is a three-dimensional shape metrology method that can achieve sub-nanometer measurement sensitivity by analyzing sets of images acquired through-focus using a conventional optical microscope. Here we present a systematic noise-analysis study for optimizing data collection and data processing parameters for TSOM and then demonstrate how the optimized parameters affect defect analysis. We show that the best balance between signal-to-noise performance and acquisition time can be achieved by judicious spatial averaging. Correct background-signal subtraction of the imaging-system inhomogeneities is also critical, as well as careful alignment of the constituent images used in differential TSOM analysis.

Effective measurement of fabricated structures is critical to the cost-effective production of modern electronics. However, traditional tip-based approaches are poorly suited to in-line inspection at current manufacturing speeds. We present the development of a large area inspection method to address throughput constraints due to the narrow field-of-view (FOV) inherent in conventional tip-based measurement. The proposed proof-of-concept system can perform simultaneous, noncontact inspection at multiple hotspots using single-chip atomic force microscopes (sc-AFMs) with nanometer-scale resolution. The tool has a throughput of ∼60 wafers / h for five-site measurement on a 4-in. wafer, corresponding to a nanometrology throughput of ∼66,000 μm2 / h. This methodology can be used to not only locate subwavelength “killer” defects but also to measure topography for in-line process control. Further, a postprocessing workflow is developed to stitch together adjacent scans measured in a serial fashion and expand the FOV of each individual sc-AFM such that total inspection area per cycle can be balanced with throughput to perform larger area inspection for uses such as defect root-cause analysis.

In this review we focus attention on the main methodological approaches for determining and visualizing nanostructural states that can be found in compacted bulk, film, or powder materials. A classification of nanostructural and nanophase materials is discussed. The main methods of structure examination, including direct electron-microscopy studies of nanomaterials, are described. We analyze the fundamental approaches and specific features of the structure and phase nanodiagnostics and describe the main phase, structural, and morphological parameters or properties of the studied materials together with the ways in which they are represented and an estimation of the errors of their determination. The main types of modern transmission and scanning microscopes are considered from the point of view of their technical characteristics and capabilities. The microscopes include attachments for elemental, structural, and texture analyses, as well as for in situ experiments on heating-, cooling-, radiation-, and deformation-induced structural and phase transformations. Various examples of electron microscopy studies of metallic, ceramic, composite, and magnetic materials are given. They were studied by electron diffraction, texture methods, and elemental analyses. The 25-year experience of scientific research performed at Electron Microscopy Center for Collective Use, Institute of Metal Physics, Ural Branch, Russian Academy of Sciences (IMP EMCCU UB RAS), is generalized.

Dimensional parameters of nanoparticles, nanostructures, and nanocoatings are the key parameters in the characterization of the objects of nanotechnology. One of the main areas in nanometrology is ensuring the uniformity of dimensional measurements at the nano- and subnanoscale. We present new types of silicon test objects which ensure the traceability of the dimensional measurements performed using scanning electron microscopes (SEMs), transmission electron microscopes (TEMs), and atomic force microscopes (AFMs) to the SI unit of length. We present the results of a determination of the thickness of silicon oxide films obtained using spectroscopic ellipsometry and transmission electron microscopy. Various metro- logical aspects of standardization used in nanotechnology are also described.

One of the limiting factors of accuracy and resolution in laser interferometry is represented by noise properties of the laser powering the interferometer. Amplitude and especially frequency fluctuations of the laser source are crucial in precision distance measurement. Sufficiently high long-term frequency stability of the laser source must be achieved especially in applications in fundamental metrology. Furthermore, the short-term frequency variations are also important primarily for measurements done at high acquisition speeds. This contribution presents practical results of measurements of short-term amplitude and frequency noises of a set of laser sources commonly used in laser interferometry. The influence of the interferometer design and electrical parameters of the detection system are also discussed.

Scanning Probe microscope (SPM) is an important nanoinstrument for several applications such as bio-research, metrology, inspection and nanopatterning. Single SPM is associated with relatively slow rate of scanning and low throughput measurement, thus not being suitable for scanning large samples such as semiconductor wafers and photolithography masks. Over the last few years we have developed a parallel high throughput SPM. This has been done by miniaturizing the SPM systems and operating many of them simultaneously. Each miniaturized SPM can be operated independently. The parallel SPM also allows the measurement of several physical parameters simultaneously; while one instrument measures nano-scale topography, another instrument can measure mechanical, electrical or thermal properties, making it a Lab-on-an-Instrument. Recently in collaboration with SwissLitho AG, thermal scanning probe lithography has also been integrated into the miniaturized SPM. This enables the fabrication of nanostructures with one or more miniaturized SPM. Moreover, an automated cantilever exchange and optical alignment system is also developed. Various types of SPM cantilevers can be exchanged in 6 seconds with an accuracy better than 2 µm. The exchange and alignment unit is miniaturized to allow for integration in the parallel SPM. Ten thousand continuous exchange and alignment cycles were performed without failure. The proof of principle (PoP) of such a mechatronics instrument will be presented in this talk. This instrument provides new research opportunities in the nanometrology and nanopatterning of wafers and nanolithography masks by enabling real die-to-die and wafer-level measurements and in cell biology by measuring the nano-scale properties of a large number of cells.

Atomic force microscopy (AFM) is an essential nanoinstrument technique for several applications such as cell biology and nanoelectronics metrology and inspection. The need for statistically significant sample sizes means that data collection can be an extremely lengthy process in AFM. The use of a single AFM instrument is known for its very low speed and not being suitable for scanning large areas, resulting in very-low-throughput measurement. We address this challenge by parallelizing AFM instruments. The parallelization is achieved by miniaturizing the AFM instrument and operating many of them simultaneously. This nanoinstrument has the advantages that each miniaturized AFM can be operated independently and that the advances in the field of AFM, both in terms of speed and imaging modalities, can be implemented more easily. Moreover, a parallel AFM instrument also allows one to measure several physical parameters simultaneously; while one instrument measures nano-scale topography, another instrument can measure mechanical, electrical or thermal properties, making it a Lab-on-an-Instrument. In this paper, a proof of principle (PoP) of such a parallel AFM instrument has been demonstrated by analyzing the topography of large samples such as semiconductor wafers. This nanoinstrument provides new research opportunities in the nanometrology of wafers and nanolithography masks by enabling real die-to-die and wafer-level measurements and in cell biology by measuring the nano-scale properties of a large number of cells.

Nanometric lateral standards are essential to nanometrology. Using laser-focused atomic deposition, a one-dimensional (1D) grating has been manufactured. The pitch of the grating is 212.8 nm, which can be traced to the laser wavelength that is accurately locked to the 52Cr atomic resonance transition 7 S 3 → 7 P 4 0 . In this paper, the uniformity rather than the pitch accuracy of the 1D grating was evaluated using atomic force microscope (AFM). Based on the center-of-gravity method, the average pitch and the nonuniformity of the grating pitch were calculated. The results show that the average pitch of the grating is 213.2 nm which deviates from the design pitch due to the calibration of AFM, and the nonuniformity of the grating is 0.1 nm. The results preliminarily prove that 1D grating fabricated by laser-focused atomic deposition has good uniformity, and has great potential to become nanometric reference material for AFM and scanning electron microscope (SEM) calibration.

This paper presents nanometrology of an ultraprecision machined surface by using optical sensors. To verify the feasibilities of optical sensors on the measurement of surface profile, different types of fiber-optic sensor and laser micro interferometer are employed to measure the roundness of a ultraprecision machined cone in this paper. Experiments confirmed that the fiber-optic sensor can measure not only the roundness but also the surface roughness of the cone. Experiments also confirm that the measurement of the laser micro interferometer is highly affected by the surface roughness of the cone because of the relative measurement principle of the laser micro interferometer.

Heterogeneous nanoparticle catalyst development relies on an understanding of their structure-property relationships, ideally at atomic resolution and in three-dimensions. Current transmission electron microscopy techniques such as discrete tomography can provide this but require multiple images of each nanoparticle and are incompatible with samples that change under electron irradiation or with surveying large numbers of particles to gain significant statistics. Here, we make use of recent advances in quantitative dark-field scanning transmission electron microscopy to count the number atoms in each atomic column of a single image from a platinum nanoparticle. These atom-counts, along with the prior knowledge of the face-centered cubic geometry, are used to create atomistic models. An energy minimization is then used to relax the nanoparticle's 3D structure. This rapid approach enables high-throughput statistical studies or the analysis of dynamic processes such as facet-restructuring or particle damage.

In-line metrologies currently used in the semiconductor industry are being challenged by the aggressive pace of device scaling and the adoption of novel device architectures. Metrology and process control of three-dimensional (3-D) high-aspect-ratio (HAR) features are becoming increasingly important and also challenging. In this paper we present a feasibility study of through-focus scanning optical microscopy (TSOM) for 3-D shape analysis of HAR features. TSOM makes use of 3-D optical data collected using a conventional optical microscope for 3-D shape analysis. Simulation results of trenches and holes down to the 11 nm node are presented. The ability of TSOM to analyze an array of HAR features or a single isolated HAR feature is also presented. This allows for the use of targets with area over 100 times smaller than that of conventional gratings, saving valuable real estate on the wafers. Indications are that the sensitivity of TSOM may match or exceed the International Technology Roadmap for Semiconductors (ITRS) measurement requirements for the next several years. Both simulations and preliminary experimental results are presented. The simplicity, lowcost, high throughput, and nanometer scale 3-D shape sensitivity of TSOM make it an attractive inspection and process monitoring solution for nanomanufacturing.

The development of new nanomaterials, devices and systems is very much dependent on the availability of new techniques for nanometrology. There now exists many advanced optical imaging techniques capable of subwavelength resolution and detection, recently brought to the forefront through the 2014 Nobel Prize for chemistry for fluorescent STED and single molecule microscopy. Label-free nanoscopy techniques are particularly interesting for nanometrology since they have the advantages of being less intrusive and open to a wider number of structures that can be observed compared with fluorescent techniques. In view of the existence of many nanoscopy techniques, we present a practical classification scheme to help in their understanding. An important distinction is made between superresolution techniques that provide resolutions better than the classical λ/2 limit of diffraction and nanodetection techniques that are used to detect or characterize unresolved nanostructures or as nanoprobes to image sub-diffraction nanostructures. We then highlight some of the more important label-free techniques that can be used for nanometrology. Superresolution techniques displaying sub-100 nm resolution are demonstrated with tomographic diffractive microscopy (TDM) and submerged microsphere optical nanoscopy (SMON). Nanodetection techniques are separated into three categories depending on whether they use contrast, phase or deconvolution. The use of increased contrast is illustrated with ellipsometric contrast microscopy (SEEC) for measuring nanostructures. Very high sensitivity phase measurement using interference microscopy is then shown for characterizing nanometric surface roughness or internal structures. Finally, the use of through-focus scanning optical microscopy (TSOM) demonstrates the measurement and characterization of 60 nm linewidths in microelectronic devices.

A prototype standard sample GSO 10030-2011 for the stepped parameters of thin layers of single crystal silicon is developed and certified. It is intended for calibration of transmission electron microscopes at magnifications of 1000–1,500,000×. The certified parameters are the step size of the stepped structure and the distance between the (111) planes of the single crystal silicon in this material. Both parameters are independently traceable to the unit of length, the meter.

Raman spectroscopy is a powerful tool to characterize the different types of sp2 carbon nanostructures, including two-dimensional graphene, one-dimensional nanotubes, and the effect of disorder in their structures. This work discusses why sp2 nanocarbons can be considered as prototype materials for the development of nanoscience and nanometrology. The sp2 nanocarbon structures are quickly introduced, followed by a discussion on how this field evolved in the past decades. In sequence, their rather rich Raman spectra composed of many peaks induced by single- and multiple-resonance effects are introduced. The properties of the main Raman peaks are then described, including their dependence on both materials structure and external factors, like temperature, pressure, doping, and environmental effects. Recent applications that are pushing the technique limits, such as multitechnique approach and in situ nanomanipulation, are highlighted, ending with some challenges for new developments in this field.

Over the last few decades the interest in phenomena on nanoscale or even atomic scale has increased significantly. A prominent, but at the same time very demanding technique is atomic force microscopy (AFM). AFM can reveal surface topographies at atomic resolution or be used to measure small forces in the range of only a few piconewtons. This exacting technique requires highly stable laser sources with specific features, including low power noise and the possibility to oppress unwanted interference. The 51nano series of lasers was specially developed to provide these indispensable features of low noise, reduced coherence and low speckle contrast in order to achieve the demanding stability standards required in nanotechnology and atomic force measurements. Particle measurements and alignment tasks are other possible applications for these stabilized, fiber-coupled laser diode beam sources.

A new version of a modulation interference microscope with long-path coordinate table resting on aeromagnetic guides that enables travel of the microscope with deviation from linearity of at most 0.1 μm on path lengths up to 300 mm has been developed. The metrological aspects of the use of the microscope for measurement of the linear dimensions of nanostructures are considered. Results of measurements of the basic parameters of the topology of integrated circuits are presented.