Advanced Metrology Research Articles

Quantum Light in Coupled Interferometers for Quantum Gravity Tests

In recent years quantum correlations have received a lot of attention as a key ingredient in advanced quantum metrology protocols. In this Letter we show that they provide even larger advantages when considering multiple-interferometer setups. In particular, we demonstrate that the use of quantum correlated light beams in coupled interferometers leads to substantial advantages with respect to classical light, up to a noise-free scenario for the ideal lossless case. On the one hand, our results prompt the possibility of testing quantum gravity in experimental configurations affordable in current quantum optics laboratories and strongly improve the precision in "larger size experiments" such as the Fermilab holometer; on the other hand, they pave the way for future applications to high precision measurements and quantum metrology.

Applications of advanced metrology techniques for the characterization of extreme ultraviolet mask blank defects

Characterization of defects and their sources is essential for developing mitigation solutions to support the production of defect-free extreme ultraviolet (EUV) mask blanks. The characterization of sub-100-nm defects pose challenges to the conventional metrology techniques, such as atomic force microscopy and scanning electron microscopy, limiting mitigation of nanoscale defects. SEMATECH’s Mask Blank Development Center houses advanced metrology capabilities that include transmission electron microscopy (TEM) and Auger electron spectroscopy (AES) to address these shortcomings. Scanning TEM was used to study the disruption of the Mo/Si multilayer of phase defects and to perform elemental analysis with energy dispersive x-ray spectroscopy that has supported projects including substrate smoothing activities, deposition simulation development, and defect printability studies. The Auger instrument was used to create elemental maps for defect identification and to characterize the ion beam deposition tool. Using advanced metrology, mitigation of small defects is being realized, yielding mask blanks with defect counts as low as eight defects at 50-nm sensitivity (Lasertec M7360 SiO 2 sphere equivalent) measured over the quality area of 132×132 mm 2 . The issues with the metrology of increasingly small EUV mask blank defects will be outlined, and comprehensive defect characterization results using TEM and AES will be presented.

Advanced Nanomeasuring Techniques for Surface Characterization

Advanced precise and accurate nanomeasurement techniques play an important role to improve the function and quality of surface characterization. There are two basic approaches, the hard measuring techniques and the soft computing measuring techniques. The advanced soft measuring techniques include coordinate measuring machines, roundness testing facilities, surface roughness, interferometric methods, confocal optical microscopy, scanning probe microscopy, and computed tomography at the level of nanometer scale. On the other hand, a new technical committee in ISO is established to address characterization issues posed by the areal surface texture and measurement methods. This paper reviews the major advanced soft metrology techniques obtained by optical, tactile, and other means using instruments, classification schemes of them, and their applications in the engineering surfaces. Furthermore, future trends under development in this area are presented and discussed to display proposed solutions for the important issues that need to be addressed scientifically.

Sub-atomic dimensional metrology: developments in the control of x-ray interferometers

Within the European Metrology Research Programme funded project NANOTRACE, the nonlinearity of the next generation of optical interferometers has been measured using x-ray interferometry. The x-ray interferometer can be regarded as a ruler or translation stage whose graduations or displacement steps are based on the lattice spacing of the crystallographic planes from which the x-rays are diffracted: in this case the graduations are every 192 pm corresponding to the spacing between the (2 2 0) planes in silicon. Precise displacement of the x-ray interferometer's monolithic translation stage in steps corresponding to discrete numbers of x-ray fringes requires servo positioning capability at the picometre level. To achieve this very fine control, a digital control system has been developed which has opened up the potential for advances in metrology using x-ray interferometry that include quadrature counting of x-ray fringes.

On the physical meaning of the power factor in acoustics

Following recent advancements in the study of time-averaged properties of energy propagation in linear acoustic fields, the well established concept of power factor known from the electric AC circuits analysis, is here extended to acoustics. This allows our outline of a complete acousto-electro-mechanic analogy, where the fundamental physical concept of energy trajectory is assimilated to a continuous line network of electric circuits, and the complex intensity vector field is defined by means of three special spatial directions: the tangent, the principal normal and the binormal direction at each point of any energy path. The notions of sound energy conductance and susceptance are then introduced and their relationship with complex intensity is highlighted. Finally, the frequency distributions of the defined quantities are measured in different acoustical contexts, thus illustrating their practical utility for advanced intensimetric metrology.

EUROanalysis 16—hot Belgrade, summer in the city

Aim and topics Belgrade was the convenient location for the 16th European Conference on Analytical Chemistry from 11 to 15 September 2011. The announced 136 oral and 560 poster contributions drew analytical chemists from Europe as well as from other parts of the world to Serbia’s capital and covered essentially all aspects of analytical sciences: analytical spectroscopy, chromatography, mass spectrometry, electroanalytical chemistry, sensors, hyphenated techniques, sample preparation and separation, bioanalytical chemistry, environmental analysis, food analysis, analytics in pharmacy and medicine, forensic analytical chemistry, advanced material analysis, chemometrics, metrology, quality assurance and reference materials, education, archaeometry.

13nm gate Intentional Defect Array (IDA) wafer patterning by e-beam lithography for defect metrology evaluation

Fabricating and inspecting wafers with defects intentionally created at known locations enables a quantitative and repeatable methodology to assess the performance of in-line defect metrology tools with regard to ITRS requirements. With each successive design node, in-line defect inspection technology becomes more challenging and there are significant concerns about the capability to support 2× and 1× technology nodes. In this paper we report progress at the College of Nanoscale Science and Engineering (CNSE) in Albany, New York, to print and process advanced defect metrology test structures intended to represent a 13nm gate length. The ISMI 13nm gate Intentional Defect Array (IDA) has lithographic defects in known locations with sizes varying from 25% to 400% of the corresponding 32nm node, resulting in defect sizes ranging from 8 to 128nm. The film stack consists of 30nm TEOS hard mask, 60nm polysilicon, 35nm TiN and 2nm HfO2 on top of silicon. The patterns are first printed (at 1×) on a 300mm wafer using a Vistec VB300 electron beam lithography tool with a high resolution HSQ resist (commercially known as Dow Corning XR-1541). The features are subsequently etched to transfer the pat- tern from the resist onto the wafer stack. The resulting IDA wafers are intended to help ISMI engineers investigate next generation metrology techniques and identify solutions for future technology nodes.

二つの外部標準による抵抗分圧器の校正

Currently, the resistive voltage divider (Fluke 752A) has been using as the instrument for extending the voltage range at most of the advanced industrial metrology laboratories. The voltage ratios belonging to this divider can be calibrated by the self-calibration or the external standard. However, the self-calibration is somewhat difficult to need the accomplished technique. Therefore, the calibration of the voltage ratios has planed the method based on a Josephson Junction Array Voltage Standard developed at the NMIJ or a Zener voltage reference (Fluke 732B) as the external standards. A Zener voltage reference used at here is the modified one for obtaining a 1V output. This paper describes how to calibrate the voltage ratios using two external standards and reveals the source of the calibration uncertainty.

Design and performance of an advanced metrology building for MIKES

Fundamental metrology is closely linked to the development of science and needs good facilities to achieve low measurement uncertainty in demanding experiments. The laboratories must have good temperature stability, low vibration level, good electromagnetic shielding, clean room air, and humidity control. This paper outlines specification and design principles of a compact laboratory building that brings most of the activities of MIKES under one roof, thus attaining the performance of the most demanding laboratories. The most demanding specifications of temperature and vibration were set for the length and mass laboratories. The tightest room temperature specification was (20 ± 0.05) °C. The vibration level was specified at the tightest level to 1 μm/s at frequencies of 0.1–5 Hz. Electromagnetic shielding was specified at best to 100 dB for plane waves up to 20 GHz. Relative humidity was specified (48 ± 2)% at 20 °C. The specifications were clearly achieved and state of the art metrology laboratories implemented.

Surface Wrinkling: A Versatile Platform for Measuring Thin‐Film Properties

Surface instabilities in soft matter have been the subject of increasingly innovative research aimed at better understanding the physics of their formation and their utility in patterning, organizing, and measuring materials properties on the micro and nanoscale. The focus of this Review is on a type of instability pattern known as surface wrinkling, covering the general concepts of this phenomenon and several recent applications involving the measurement of thin-film properties. The ability of surface wrinkling to yield new insights into particularly challenging materials systems such as ultrathin films, polymer brushes, polyelectrolyte multilayer assemblies, ultrasoft materials, and nanoscale structured materials is highlighted. A perspective on the future directions of this maturing field, including the prospects for advanced thin-film metrology methods, facile surface patterning, and the control of topology-sensitive phenomena, such as wetting and adhesion, is also presented.

Composition-Explicit Distillation Curves of Waste Lubricant Oils and Resourced Crude Oil: A Diagnostic for Re-Refining and Evaluation

Problem statement: We have recently introduced several important improvements in the measurement of distillation curves for complex fluids. The modifications include a composition-explicit data channel for each distillate fraction and temperature measurements that are true thermodynamic state points that can be modeled with an equation of state. The composition-explicit information is achieved with a sampling approach that allows precise qualitative as well as quantitative analyses of each fraction, on the fly. We have applied the method (called the advanced distillation curve technique) to a variety of fluids, including simple n-alkanes, rocket propellants, gasoline, jet fuels, diesel and biodiesel fuels and crude oils (both petroleum-and bio-derived crude oils). Approach: In this study, we present the application of the method to new, recycled and resourced heavy oils. The ultimate purpose of this work is waste reduction and energy utilization, by placing the reprocessing steps on a more fundamental footing. First, we present measurements on four unused automotive crankcase oils and then four samples of used oils: automotive oil, cutting oil, transformer oil and a commingled lubricant waste stream. Using the advanced distillation curve metrology, we can distinguish between the different weights (viscosity ranges) of crankcase oils and compare them to the sample of used crankcase oil. The distillation curves also provide valuable information regarding the presence or absence of low-boiling contaminants in the recycled automotive oil, such as water and gasoline. Results: Additionally, we demonstrate the evaluation of all four used lubricant oils. Then, we apply the advanced distillation curve method to a sample of crude oil prepared using a plastic waste stream from an automotive plant. Conclusion: Overall, we conclude that the composition-explicit advanced distillation curve metrology is important for understanding the boiling behavior of the various oils streams and is a valuable diagnostic for future re-refining of the used lubricant oils. This information will be essential in the development of models for the thermophysical properties of such fluids.

Composition-Explicit Distillation Curves for Mixtures of Gasoline and Diesel Fuel with γ-Valerolactone

Interest in the domestic production of bioderived fuels, sparked by the high cost of petroleum crude oil, the potential of supply disruptions, and fears about climate change has led to consideration of fluids to replace or extend conventional petroleum derived fuels. While ethanol as a gasoline oxygenate and extender has received a great deal of attention, this fluid has numerous problems such as aggressive behavior toward engine components and a relatively low energy content. Many other fluids have been considered as oxygenates for gasoline, such as the butanols, ethers, and other alcohols. For diesel fuel, oxygenates have included glycol ethers, glycol esters, carbonates, acetates, and ethers. Some of these oxygenates and extenders can be made from biomass and are thus renewable and in some cases can decrease the overall carbon dioxide budget. One new renewable fluid being considered as both a gasoline and diesel fuel oxygenate is γ-valerolactone. In this paper, we present a characterization of selected mixtures of γ-valerolactone in both gasoline (mixtures of 10, 20, and 30%, vol/vol) and diesel fuel (1 and 2.5%, vol/vol), performed with the advanced distillation curve metrology. This method features: (1) a composition explicit data channel for each distillate fraction (for both qualitative and quantitative analysis); (2) temperature measurements that are true thermodynamic state points that can be modeled with an equation of state; (3) temperature, volume, and pressure measurements of low uncertainty suitable for equation of state development; (4) consistency with a century of historical data; (5) an assessment of the energy content of each distillate fraction; (6) trace chemical analysis of each distillate fraction; and (7) corrosivity assessment of each distillate fraction. We discuss the effect of γ-valerolactone on the vapor−liquid equilibrium (volatility) of the mixtures.

Metrology-assisted robotic processing of aerospace applications

Modern aerospace structures tend to consist of large numbers of geometrically complex structural components which by their very nature tend to suffer from significant levels of physical distortion and are thus difficult to assemble. One solution to this problem is to use large complex jigs which physically control the shape of the parts. These jigs are usually loaded using either direct manual labour or manual labour assisted by cranes or lifting devices. The use of manual operations represents a significant health and safety risk and increased likelihood of damaging components during assembly. The application of automation in the processing of such structures has so far been confined to small product specific cells owing to difficulties in pre-defining and fixing the exact geometry and positioning of parts within the work volume. The use of specially designed jigs, fixtures and aids such as drilling templates can be adapted to support automation but are expensive, have long manufacturing lead times and cannot be economically modified for use on other aircraft types. The paper proposes a solution to the above problems using standard industrial robots and an advanced control and non-contact metrology systems. The developed methodology is generic and has been evaluated and demonstrated in a number of different applications. The application described in this paper is the assembly of regional jet fuselage panels. Results are presented along with an analysis of the accuracy and repeatability of the system and its elements.

Characterization of pattern-placement error for sub-40-nm memory devices

Pattern-placement error (PPE) due to lens aberration is characterized for sub-40-nm memory devices. The amount of PPE depends on the feature size. PPE difference between memory cell and traditional box-in-box or advanced imaging metrology marks of KLA-Tencor Corporation is 4nm in the worst case for a given illumination condition. To avoid this kind of problem, a cell-like segmentation may be applied for alignment and overlay marks. However, the cell-like segmentation could degrade the alignment-signal intensity. In this article, a simple but effective methodology is introduced so that optimum segmentation size is determined. As a result, PPE error of alignment/overlay marks is close to memory cells with enough alignment-signal intensity.

Advanced Metrology Centre for Heriot-Watt University

Advanced Metrology Centre for Heriot-Watt University

Analysis and Optomechanical Characterisation of a MEMS Micromirror Device

Abstract: Advances in our analysis and characterisation of a micro‐electromechanical system (MEMS) micromirror device are presented. The micromirror device, to be used as an integral component of an interferometer, has a characteristic dimension of 510 μm and operates in a dynamic mode with maximum out‐of‐plane displacements in the order of 10 μm at oscillation frequencies of up to 1.3 kHz. Developments are carried out by analytical, computational and experimental methods. Analytical and computational nonlinear geometrical models are developed in order to determine the optimal loading‐displacement operational characteristics of the micromirror. Because of the operational mode of the micromirror, the experimental characterisation of its loading‐displacement transfer function requires utilisation of advanced optical metrology methods. Optoelectronic holographic microscopy (OEHM) methodologies, based on multiple wavelengths being developed to perform such characterisation, are described. The micromirror device is suitable for optical phase measurements and applicable to development of miniaturised optical metrology systems for characterisation of shapes and deformations.

Uncovering energy-efficiency opportunities in data centers

The combination of rapidly increasing energy use of data centers (DCs), which is triggered by dramatic increases in IT (information technology) demands, and increases in energy costs and limited energy supplies has made the energy efficiency of DCs a central concern from both a cost and a sustainability perspective. This paper describes three important technology components that address the energy consumption in DCs. First, we present a mobile measurement technology (MMT) for optimizing the space and energy efficiency of DCs. The technology encompasses the interworking of an advanced metrology technique for rapid data collection at high spatial resolution and measurement-driven modeling techniques, enabling optimal adjustments of a DC environment within a target thermal envelope. Specific example data demonstrating the effectiveness of MMT is shown. Second, the static MMT measurements obtained at high spatial resolution are complemented by and integrated with a real-time sensor network. The requirements and suitable architectures for wired and wireless sensor solutions are discussed. Third, an energy and thermal model analysis for a DC is presented that exploits both the high-spatial-resolution (but static) MMT data and the high-timeresolved (but sparse) sensor data. The combination of these two data types (static and dynamic), in conjunction with innovative modeling techniques, provides the basis for extending the MMT concept toward an interactive energy management solution.

Laser-produced X-ray sources

A formidable array of advanced laser systems are emerging that produce extreme states of light and matter. By irradiating solid and gaseous targets with lasers of increasing energy densities, new physical regimes of radiation effects are being explored for the first time in controlled laboratory settings. One result that is being accomplished or pursued using a variety of techniques, is the realization of novel sources of X-rays with unprecedented characteristics and light–matter interactions, the mechanisms of which are in many cases still being elucidated. Examples include the megajoule class of laser-produced plasmas designed in pursuit of alternative-energy and security applications and the petawatt class of lasers used for fast ignition and X-ray radiographic applications such as medical imaging and real-time imaging of plasma hydrodynamics. As these technologies mature, increased emphasis will need to be placed on advanced instrumentation and diagnostic metrology to characterize the spectra, time structure, and absolute brightness of X-rays emitted by these unconventional sources. Such customized and absolutely calibrated measurement tools will serve as an enabling technology that can help in assessing the overall system performance and progress, as well as identification of the underlying interaction mechanisms of interest to basic and applied strong-field and high-energy-density science.

Composition-Explicit Distillation Curves for Mixtures of Gasoline with Four-Carbon Alcohols (Butanols)

Interest in the domestic production of bioderived fuels, sparked by the high cost of petroleum crude oil, has led to consideration of fluids to replace or extend conventional petroleum-derived fuels. While ethanol as a gasoline extender has received a great deal of attention, this fluid has numerous problems, such as aggressive behavior toward engine components and a relatively low energy content. For these and other reasons, the butanols have been studied as gasoline extenders. For any extender to be designed or adopted, a suitable knowledge base of thermophysical properties is a critical requirement. In this paper, we provide volatility measurements of mixtures of a typical gasoline with n-butanol, 2-butanol, isobutanol, and t-butanol, performed with the advanced distillation curve metrology. This recently introduced technique is an improvement of classical approaches, featuring (1) a composition-explicit data channel for each distillate fraction (for both qualitative and quantitative analyses), (2) tem...

Advanced Metrology for Nanoelectronics at the National Institute of Standards and Technology

A broad range of programs at the National Institute of Standards and Technology address critical metrology and characterization challenges facing the nanoelectronics industry. A brief history of the program will be included. From these programs we will describe some exemplary projects developing new measurement and characterization techniques for nanodevices. These will include, among others, the use of helium ion microscope, spin-transfer microwave nano-oscillators, characterization of graphene, advanced atomic force microscope, and development of a microcalorimeter-based high resolution X-ray analyzer.