Proceedings Volume 6648

Instrumentation, Metrology, and Standards for Nanomanufacturing

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Proceedings Volume 6648

Instrumentation, Metrology, and Standards for Nanomanufacturing

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Volume Details

Date Published: 10 September 2007
Contents: 6 Sessions, 21 Papers, 0 Presentations
Conference: NanoScience + Engineering 2007
Volume Number: 6648

Table of Contents

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Table of Contents

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  • Front Matter: Volume 6648
  • Instrumentation Metrology and Standards I
  • Instrumentation and Metrology II
  • Integration, Interoperability, and Information Management I
  • Integration, Interoperability, and Information Management II
  • Poster Session
Front Matter: Volume 6648
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Front Matter: Volume 6648
This PDF file contains the front matter associated with SPIE Proceedings Volume 6648, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.
Instrumentation Metrology and Standards I
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Instrumentation, metrology, and standards: key elements for the future of nanomanufacturing
Nanomanufacturing is the essential bridge between the discoveries of nanoscience and real world nanotech products and is the vehicle by which the Nation and the World will realize the promise of major technological innovation across a spectrum of products that will affect virtually every industrial sector. For nanotech products to achieve the broad impacts envisioned, they must be manufactured in market-appropriate quantities in a reliable, repeatable, economical and commercially viable manner. In addition, they must be manufactured so that environmental and human health concerns are met, worker safety issues are appropriately assessed and handled, and liability issues are addressed. Critical to this realization of robust nanomanufacturing is the development of the necessary instrumentation, metrology, and standards. Integration of the instruments, their interoperability, and appropriate information management are also critical elements that must be considered for viable nanomanufacturing. Advanced instrumentation, metrology and standards will allow the physical dimensions, properties, functionality, and purity of the materials, processes, tools, systems, products, and emissions that will constitute nanomanufacturing to be measured and characterized. This will in turn enable production to be scaleable, controllable, predictable, and repeatable to meet market needs. If a nano-product cannot be measured it cannot be manufactured; additionally if that product cannot be made safely it should not be manufactured. This presentation introduces the Instrumentation, Metrology, and Standards for Nanomanufacturing Conference at the 2007 SPIE Optics and Photonics. This conference will become the leading forum for the exchange of foundational information and discussion of instrumentation, metrology and standards which are key elements for the success of nanomanufacturing.
Infrared reflectivity spectroscopy of optical phonons in short-period AlGaN/GaN superlattices
J. B. Herzog, A. M. Mintairov, K. Sun, et al.
GaN and AlN compounds have been proven useful in wide bandgap microelectronics and optoelectronics. Also properties of bulk GaN and AlN have been studied extensively. However, many characteristics of AlGaN/GaN superlattices are not well known. In particular, the properties of phonons have not been determined. In order to determine phonon properties, this study measured infrared reflectivity spectra on short period superlattices, which were grown by high quality molecular beam epitaxy. The superlattices consisted of 300 periods of alternating layers of GaN and AlGaN, each containing between 1 and 8 monolayers. Next, the reflectivity of each sample was measured using a Bruker IFS-66V spectrometer. From these experimental spectra the dielectric function, and hence the optical phonon properties (namely phonon frequency and phonon damping), were determined. Mapping the experimental spectra with theoretical calculations determined the longitudinal and transverse optical phonon energies present in the AlGaN/GaN superlattices. Through the examination of different AlGaN/GaN superlattice combinations, plots of phonon energies versus material composition were obtained. Furthermore, new phonons, that were not present in bulk AlN and GaN, were discovered. Finally, phonon characteristics were measured as a function of temperature, confirming that phonon energies decrease with increasing temperature.
Near-field birefringence response in thickness direction of liquid crystal thin film
Information of molecular orientation in nematic LC (liquid crystal) is attractive and important for application in the field of display device. In this paper, we demonstrate a novel method using Birefringence Scanning Near-field Optical Microscope (Bi-SNOM) with a probe which is inserted into the LC thin film to detect the molecular orientation from its birefringence responses in the thickness direction of LC thin film. The probe is laterally vibrated while going forward into LC thin film, and the retardation and azimuth angle are being recorded as the probe going down. Since the affection of shear force acts as a stimulation to LC molecules, the orientation of molecules is changed and reorientated. In this study, LC thin film on homeotropic alignment LC film and homogenious alignment LC film were measured. In the case of homogenious alignment LC film, we propose two experiments; one is the experiment in which the vibration direction of probe is vertical to the alignment direction of PI film, and in the other experiment, we vibrated the probe in the direction parallel to the rubbing direction of alignment layer. We also compared the data measured with no vibration probe and the data measured with probe vibrated vertical to the alignment direction. As results, we obtained the orientation of molecules above the alignment layer by the birefringence response of LC molecules to the disturbance of vibrating probe and the anchoring extrapolation length by Polyimide (PI) alignment substrate. Ultimately, the LC thin film can be modeled in thickness direction from all the results using this method.
Instrumentation and Metrology II
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The helium ion microscope: a new tool for nanomanufacturing
Michael T. Postek, Andras E. Vladár, John Kramar, et al.
Helium Ion Microscopy (HIM) is a new, potentially disruptive technology for nanotechnology and nanomanufacturing. This methodology presents a potentially revolutionary approach to imaging and measurements which has several potential advantages over the traditional scanning electron microscope (SEM) currently in use in research and manufacturing facilities across the world. Due to the very high source brightness, and the shorter wavelength of the helium ions, it is theoretically possible to focus the ion beam into a smaller probe size relative to that of an electron beam of an SEM. Hence higher resolution is theoretically possible. In an SEM, an electron beam interacts with the sample and an array of signals are generated, collected and imaged. This interaction zone may be quite large depending upon the accelerating voltage and materials involved. Conversely, the helium ion beam interacts with the sample, but it does not have as large an excitation volume and thus the image collected is more surface sensitive and can potentially provide sharp images on a wide range of materials. The current suite of HIM detectors can provide topographic, material, crystallographic, and electrical properties of the sample. Compared to an SEM, the secondary electron yield is quite high - allowing for imaging at extremely low beam currents and the relatively low mass of the helium ion, in contrast to other ion sources such as gallium results in no discernable damage to the sample. This presentation will report on some of the preliminary work being done on the HIM as a research and measurement tool for nanotechnology and nanomanufacturing at NIST.
Length calibration standards for nano-manufacturing
David C. Joy, Sachin Deo, Brendan J. Griffin
The physical dimensions of nanoscale objects are an important indicator of their functionality. However, measuring feature size from a SEM image is difficult not only because of fundamental considerations, such as the nature of beam interactions and the information transfer properties of the microscope, but because the magnification of the SEM image from which a measurement will be made is completely uncalibrated and additionally is subject to local distortions and variations. Nano-gauges fabricated by electron beam lithography - one or two dimensional structures on the size scale of the objects of interest - provide a local length standards within the image field from which the relative size of features can be accurately determined. In order to provide an absolute measurement of size the dimensions of the nano-gauge structure must themselves be calibrated against some primary standard. Because there are no convenient standards of appropriate scale available we propose that this can be done using a moiré fringe technique to bridge the gap between the nanoscale and common length standards such as ruled diffraction gratings.
Microstructure of 100 nm damascene copper overburden and lines
A detailed understanding of the crystallography of metallic conductors in modern interconnect systems is essential if we are to understand the influence of processing parameters on performance and reliability. In particular we must be able to evaluate the grain size, crystallographic orientation and residual elastic stress for interconnect lines having widths of tens of nm. Transmission electron microscopy might be the obvious choice, but sample preparation and small sample size make this technique unattractive. On the other hand, electron backscatter diffraction, EBSD, in a scanning electron microscope provides a very attractive tool. Sample preparation can be relatively simple, especially if one investigates the structures immediately after CMP; whole wafers may be measured if desired. One limitation to EBSD is that good diffraction patterns are obtained only from free surfaces and from a limited depth, say a few hundred nm in copper. Here EBSD will be used to compare structures for the pads and 100-nm lines in two variants of a commercial copper damascene interconnect structure. EBSD data collection will be discussed as optimized for characterizing differences in the texture, which were attributed to differences in the processing. By a unique approach to EBSD mapping we found that neither the texture nor the grain size of the overburden, as represented by the contact pads, propagated into the 100 nm lines, though they did propagate into some wider lines.
Nanomanufacturing via fast laser-induced self-organization in thin metal films
C. Favazza, H. Krishna, R. Sureshkumar, et al.
Robust nanomanufacturing methodologies are crucial towards realizing simple and cost-effective products. Here we discuss nanofabrication of ordered metal nanoparticles through pulsed-laser-induced self-organization. When ultrathin metal films are exposed to short laser pulses, spontaneous pattern formation results under appropriate conditions. Under uniform laser irradiation two competing modes of self-organization are observed. One, a thin film hydrodynamic dewetting instability due to the competition between surface tension and attractive van derWaals interactions, results in nanoparticles with well-defined and predictable interparticle spacings and sizes with short range spatial order. The second, thermocapillary flow due to interference between the incident beam and a scattered surface wave, results in laser induced periodic surface structures. Non-uniform laser irradiation, such as by 2-beam laser interference irradiation, initiates a tunable thermocapillary effect in the film giving rise to nanowires, and continued laser irradiation leads to a Rayleigh-like breakup of the nanowires producing nanoparticles with spatial long-range and short-range order. These self-organizing approaches appear to be applicable to a variety of metal films, including Co, Cu, Ag, Fe, Ni, Pt, Zn, Ti, V and Mn. These results suggest that laser-induced self-organization in thin films could be an attractive route to nanomanufacture well-defined nanoparticle arrangements for applications in optical information processing, sensing and solar energy harvesting.
Integration, Interoperability, and Information Management I
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Integration, interoperability, and information management: What are the key issues for nanomanufacturing?
Nanomanufacturing can be defined as all manufacturing activities that collectively support an approach to design, produce, control, modify, manipulate, and assemble nanometer scale objects and features for the purpose of fabricating a product or system that exploits properties seen at the nanoscale. This includes information technologies and systems that support each aspect of this collective approach. This paper focuses on research topics centered on information technology for manufacturing and metrology applications that are broadly grouped into three categories: integration, interoperability, and information management.
Modelling of angle-resolved x-ray photoelectron spectroscopy (ARXPS) intensity ratios for nanocharacterisation of closely packed shell-core nanofibres
Jian Wang, Peter J. Cumpson
Shell-core nanofibres are structured nanoparticles that are increasingly of technological importance. Angle-resolved X-ray photoelectron spectroscopy (ARXPS) is potentially an excellent technique to characterise surfaces formed by this type of nanoparticles. We present both analytical and Monte Carlo models predicting the ARXPS intensity ratios of a monolayer of shell-core nanofibres on a flat substrate as a function of the photoelectron emission angle, the core size and the shell thickness. In the analytical model, the XPS intensities are calculated by integrating over one whole nanofibre following the photoelectron trajectories towards the detector using a generalized XPS measurement expression. The effects of nanoparticle structure, the influence from neighboring nanoparticles and the dependence of attenuation length on material composition are all accounted for. The results are distributions of XPS intensity from shell and core at various emission angles from which the ARXPS intensity ratios are obtained. In parallel we develop a Monte Carlo simulation code to cross validate it in tractable special cases and to extend its potential application to a wider range of geometry. A few artificial shell-core structured nanofibres of different geometrical and material parameters are used to test the two models. Agreement between them is excellent. Their potential applications are illustrated and discussed using scenarios corresponding to measuring oxidized, passivated, coated or contaminated nanoparticles and to monitoring a process of oxidation or passivation.
Optimal architecture of a neural network for a high precision in ellipsometric scatterometry
Issam Gereige, Stéphane Robert, Gérard Granet
Neural networks (NN) have received a great deal of interest over the last few years. They are being applied accross a wide range of problems in pattern recognition, artificial intelligence, and classification as well as in the inverse problem of scatterometry. Optical scatterometry is a non-direct characterization method that has been widely employed in the semiconductor industry for critical dimensions control. It is based on the analysis of the light scattered from periodic structures. This analysis consists of the resolution of an inverse problem in order to determine the parameters defining the geometrical shape of the structure. In this work, we will study the performances of the NN according to various internal parameters when it is applied to solve the scattered problem. This will allow us to examine how a NN reacts and to select the optimal configuration of these parameters leading to a rapid and accurate characterization.
Nano-precision dynamic motion control
This paper presents digital motion control algorithms, real-time implementation, and experimental results for dynamic motion control. A digital control system that includes robust feedback, previewed feedforward, and repetitive control action is implemented on a piezoelectric actuator driven mechanical stage and is demonstrated to achieve nanometer level dynamic precision.
Combining coordinate measurement and nanometrology for large-range nanoscale metrology
The Nanometer-Coordinate-Measuring-Machine (NCMM) is developed for comparatively fast large area scans with high resolution for measuring critical dimensions. The system combines a metrological atomic force microscope (AFM) with a precise positioning system. The sample is moved under the probe system via the positioning system achieving a scan range of 25 x 25 x 5 mm3 with a resolution of 1.24 nm. An AFM has a resolution beyond the wavelength of light and is a material-variable sensor. The cantilever of the used AFM can only be moved up and down via a monolytic piezoblock avoiding dynamic crosstalk. Combined with the up and down movement of the positioning system a multistage measurement is achieved. Through its overall coordinate system, the NCMM can scan very fast, since just regions of interest have to be scanned and no stitching procedures are needed afterwards. The measurements are traceable to the meter-definition since all movements of the drives and the AFMs cantilever are measured via laser-interferometers and the Abbé-principle is kept in every dimension. To meet thermal demands, materials with low thermal expansion coefficients are used and the metrological frame is kept small. A focus is on automating the measurements by the use of a-priori-knowledge of the sample, optical navigation and image processing.
Integration, Interoperability, and Information Management II
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Computational modeling of laser-induced self-organization in nanoscopic metal films for predictive nanomanufacturing
Justin Trice, Ramki Kalyanaraman, Radhakrishna Sureshkumar
Computer models that accurately predict the dynamics of nanoscale self-organization are vital towards knowledge-based nanomanufacturing. Here we present a first principles computational model of laser induced self-organization of thin metallic films (thickness <= 30 nm ) into nanoscale patterns which eventually evolve into ordered nanoparticles. The pattern formation is initiated by a thin film hydrodynamic instability and the ensuing length scales are related to the intrinsic materials properties such as surface tension and van der Waal's dispersion forces. We discuss a fully implicit, finite-difference method with adaptive time step and mesh size control for the solution of the nonlinear, fourth-order PDE governing the thin film dynamics. These simulations capture the changing morphology of the film due to the competition between surface tension and van der Waals forces. Simulation results are used to understand the nonlinear amplifcation of film height perturbations ~(KT/γ)1/2, where K, T and γ represent the Boltzmann constant, absolute temperature, and surface tension respectively,leading eventually to film rupture.
In silico design of metal-dielectric nanocomposites for solar energy applications
Justin Trice, Hernando Garcia, Radhakrishna Sureshkumar, et al.
Recently, a homogenization procedure has been proposed, based on the tight lower bounds of the Bergman- Milton formulation, and successfully applied to dilute ternary nanocomposites to predict optical data without using any fitting parameters [Garcia et al. Phys. Rev. B, 75, 045439 (2007)]. The procedure has been extended and applied to predict the absorption coefficient of a quaternary nanocomposite consisting of Cu, Ag, and Au nanospheres embedded in a SiO2 host matrix. Significant enhancement of the absorption coefficient is observed over the spectral range 350-800 nm. The magnitude of this enhancement can be controlled by varying the nanosphere diameter and the individual metal volume fraction with respect to the host matrix. We have determined the optimal composition resulting in enhanced broadband (350nm-800nm) absorption of the solar spectrum using a simulated annealing algorithm. Fabricating such composite materials with a desired optical absorption has potential applications in solar energy harvesting.
A CAD integration framework for designing devices with atomic scale resolution
Yu-Chi Chang, Krishnan Ramaswami, Miguel Pinilla, et al.
The rapid development in nano-scale fabrication processes and techniques demands efficient CAD tools to facilitate the design process at nano-scale. Numerous CAD systems are available for constructing molecular structures, atom by atom. However, these tools are generally developed to assist quantum or molecular analyses and simulations for relatively small clusters, which typically involve tens to hundreds of atoms for quantum simulations, and hundreds to thousands of atoms for molecular dynamics simulations. They are not designed for larger structures at the device level, which usually consist of hundreds of such clusters. Conventional CAD tools manage the geometry of one device concisely via the boundary of the device, which is the aggregated shape of the clusters. However, such boundary representations do not provide the association between the boundary and its underlying atomic clusters. Establishing such association will allow modification of the clusters thereby reflecting the device geometry in a coherent fashion. Accordingly, we can quickly switch between two different levels of representation. As a result, one benefits from the concise shape representation at the device level, while enabling the editing of molecular entities as well. In this paper, we propose a "skeleton" geometry mapping method to establish the needed association for fast switching between different levels, and an assembly tree "level-of-detail" architecture which allows to quickly locate and locally update design modifications.
Poster Session
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A novel low-cost high-throughput probe card scanner analyzer for characterization of magnetic tunnel junctions
Philip W. T. Pong, Moshe Schmoueli, Eliezer Marcus, et al.
The advancement of the technology of magnetic tunnel junctions (MTJs) greatly hinges on the optimization of the magnetic materials, fabrication process, and annealing conditions which involve characterization of a large number of samples. As such, it is of paramount importance to have a rapid-turnaround characterization method since the characterization process can take even longer time than the fabrication. Conventionally, micropositioners and probe tips are manually operated to perform 4-point electrical measurement on each individual device which is a time-consuming, low-throughput process. A commercial automatic probe card analyzer can provide high turnaround; however, it is expensive and involves much cost and labor to install and maintain the equipment. In view of this, we have developed a novel low-cost, home-made, high-throughput probe card analyzer system for characterization of MTJs. It can perform fast 4-probe electrical measurements including current vs voltage, magnetoresistance, and bias dependence measurements with a high turnaround of about 500 devices per hour. The design and construction of the system is discussed in detail in this paper.
Silicon test object of the linewidth of the nanometer range for SEM and AFM
Yu. A. Novikov, V. P. Gavrilenko, Yu. V. Ozerin, et al.
The results of the study of a test object on scanning electron microscopes and atomic force microscopes are presented. The test object presents a relief on a monosilicon surface, and it is fabricated by the anisotropic etching of monosilicon. The relief elements have a trapezoidal profile with large angles of inclination of the sidewalls. The sides of the relief elements coincide with the crystallographic planes {100} and {111} of silicon. The test object is intended for calibration of scanning electron microscopes and atomic force microscopes.
Measurements of linear sizes of relief elements in the nanometer range using an atomic force microscope
P. A. Todua, M. N. Filippov, V. P. Gavrilenko, et al.
The results of the study of image formation in atomic force microscope (AFM) are presented. Effects of the radius and the angular characteristics of the cantilever tip, as well as of the relief of the surface being studied, on the signal shape are discussed. Methods of AFM calibration, including the calibration of all three scales with the use of only one certified size of a test object and the measurement of the cantilever tip radius, are presented. Formulas are obtained that relate the sizes of trapezoidal structures to the sizes of the control intervals chosen in the AFM signals.
Measurements of linear sizes of relief elements in the nanometer range using a scanning electron microscope
V. P. Gavrilenko, M. N. Filippov, Yu. A. Novikov, et al.
We present results of the study of forming the image in a scanning electron microscope (SEM). The effects of the electron beam energy and of the beam diameter on the signal profile are demonstrated. Methods of SEM calibration including the measurement of the electron beam diameter are presented. The formulas relating the size of the trapezoidal structures to the length of the reference portions of the SEM signals are presented. Examples of measurements of linear sizes of relief structures are given.
Spatial redistribution of nano-particles using electrokinetic micro-focuser
Current microfabrication technologies rely on top-down, photolithographic techniques that are ultimately limited by the wavelength of light. While systems for nanofabrication do exist, they frequently suffer from high costs and slow processing times, creating a need for a new manufacturing paradigm. The combination of top-down and bottom-up fabrication approaches in device construction creates a new paradigm in micro- and nano-manufacturing. The pre-requisite for the realization of the manufacturing paradigm relies on the manipulation of molecules in a deterministic and controlled manner. The use of AC electrokinetic forces, such as dielectrophoresis (DEP) and AC electroosmosis, is a promising technology for manipulating nano-sized particle in a parallel fashion. A three-electrode micro-focusing system was designed to expoit this forces in order to control the spatial distribution of nano-particles in different frequency ranges. Thus far, we have demonstrated the ability to concentrate 40 nm and 300 nm diameter particles using a 50 μm diameter focusing system. AC electroosmotic motion of the nano-particles was observed while using low frequencies (in a range of 30 Hz - 1 KHz). By using different frequencies and changing the ground location, we have manipulated the nano-particles into circular band structures with different width, and focused the nanoparticles into circular spots with different diameters. Currently, we are in the progress of optimizing the operation parameters (e.g. frequency and AC voltages) by using the technique of particle image velocimetry (PIV). In the future, design of different electrode geometries and the numerical simulation of electric field distribution will be carried out to manipulate the nano-particles into a variety of geometries.