Clayton Teague

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Optical techniques for on-line measurement of surface topography

Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, Apr 1, 1981

... Parametric techniques are fast but the results are hard to quantify in terms of surfacetopogr... more

Relief‐exposure characteristics of radiographs in relief

Journal of Applied Physics, Feb 1, 1978

Highly exposed radiographs are utilized in microradiography in order to increase the signal-to-no... more Highly exposed radiographs are utilized in microradiography in order to increase the signal-to-noise ratio. Relief radiography enables the evaluation of these microradiographs. Relief-exposure characteristics are shown to follow a relationship of the type R=Rm[1−exp(−E/Em)], where R is the relief height, E is the exposure, and Rm and Em are constants. The density of developed silver in Ilford L-4 nuclear emulsion is found from the value of Rm to be 2.86. The constant Em is shown to give the exposure for maximum contrast. The experimental results are discussed and compared to those found in the literature.

Scanning tip microscopies: An overview and some history

Proceedings ... annual meeting, Electron Microscopy Society of America, 1988

The generic concept of scanned tip microscopy is much the same as the conventional scanning elect... more The generic concept of scanned tip microscopy is much the same as the conventional scanning electron microscope. Both provide a one-to-one mapping between a point sampling of some physical property of a probe-sample surface interaction and a corresponding point in an image. Correspondence between points on the sample surface and image points is achieved by synchronizing the image generation process with probe motion. Probe motion is generally in a rastered or boustrophedon path over a selected area of the sample (Fig.1). A very lucid description of this generic microscope concept is given in a paper by Matey and Blanc. The major differences with tip microscopy methods are that no lenses are used, probe motion relative to the specimen is produced mechanically, and the probe is a solid material.Although the roots of scanned tip microscopy extend back almost twenty years to the work of Williamson with diamond styli and Young et al.

United States National Nanotechnology Initiative

Epidemiology, Sep 1, 2005

Spatial RAM for high precision data acquisition systems

European Society for Precision Engineering and Nanotechnology 10 th Anniversary International Conference

<title>Grating pitch measurements with the molecular measuring machine</title>

Proceedings of SPIE, Nov 30, 1999

At the National Institute of Standards and Technology, we are building a metrology instrument cal... more At the National Institute of Standards and Technology, we are building a metrology instrument called the Molecular Measuring Machine (M3) with the goal of performing nanometer- accuracy two-dimensional feature placement measurements over a 50 mm by 50 mm area. The instrument uses a scanning tunneling microscope to probe the surface and an interferometer system to measure the lateral probe movement, both having sub-nanometer resolution. The continuous vertical measurement range is 5 micrometer, and up to 2 mm can be covered by stitching overlapping ranges. The instrument includes temperature control with millikelvin stability, an ultra-high vacuum environment with a base pressure below 10-5 Pa, and seismic and acoustic vibration isolation. Pitch measurements were performed on gratings made by holographic exposure of photoresist and on gratings made by laser-focused atomic deposition of Cr. The line pitch for these gratings ranged from 200 nm to 400 nm with an estimated standard uncertainty of the average pitch of 25 X 10-6. This fractional uncertainty is derived from an analysis of the sources of uncertainty for a 1 mm point-to- point measurement, including the effects of alignment, Abbe offset, motion cross-coupling, and temperature variations. These grating pitch measurements are uniquely accomplished on M3 because of the combination of probe resolution and long-range interferometer-controlled stage. This instrument could uniquely address certain dimensional metrology needs in the data storage industry.

Surface Roughness Metrology By Angular Distributions Of Scattered Light

Proceedings of SPIE, Sep 3, 1985

On-line industrial inspection of batch manufactured parts requires fast measurement techniques fo... more On-line industrial inspection of batch manufactured parts requires fast measurement techniques for surface finish quality. In order to develop the measurement basis for these techniques, a system has been built to determine surface roughness by measuring the angular distributions of scattered light. The system incorporates data gathered from the angular distribution instrument and traditional surface stylus instruments. These data are used both as input and as comparison data in order to test various mathematical models of optical scattering phenomena. The object is to develop a mathematical model that uses the angular distribution of scattered light to deduce surface roughness parameters such as Ra and surface wavelength. This paper describes the results of an experiment in which angular scattered data from surfaces with sinusoidal profiles was used to compute the surface R and wavelength. Stylus measurements of these parameters were made separately. A comparative table is given of the computed and measured values. Estimates of uncertainties are also given.

Toward nanometer accuracy measurements

Proceedings of SPIE, Jun 14, 1999

We at NIST are building a metrology instrument called the Molecular Measuring Machine (MMM) with ... more We at NIST are building a metrology instrument called the Molecular Measuring Machine (MMM) with the goal of performing 2D point-to-point measurements with one nanometer accuracy cover a 50 mm by 50 mm area. The instrument combines a scanning tunneling microscope (STM) to probe the surface and a Michelson interferometer system to measure the probe movement, both with sub-nanometer resolution.

Measurements of stylus radii

Wear, Nov 1, 1979

Abstract In stylus measurements of surface texture the measured results for roughness depend on t... more Abstract In stylus measurements of surface texture the measured results for roughness depend on the stylus radius. Therefore it is important to determine the stylus radius. Since stylus tips are not perfectly spherical, the local radius of curvature varies significantly over the surface which makes the determination of an effective radius difficult. Both the techniques used to generate stylus profiles and the subsequent algorithms used to derive an effective radius are discussed. Comparisons are made between three techniques: sharp-edge traces, optical microscopy and scanning electron microscopy. Several algorithms, including that prescribed by the American National Standard ANSI B46-1, are discussed. It is concluded that the radius scale method is accurate, unambiguous and easy to use for routine measurements in the laboratory.

Surface texture characterization by angular distributions of scattered light

Work at the National Bureau of Standards to develop an on-line optical measurement device and att... more Work at the National Bureau of Standards to develop an on-line optical measurement device and attendant algorithms for automated optical scattering measurements of machined metal surfaces are described. The surfaces could be milled, ground or lapped, and the system is intended to categorize the resulting surface characteristics. The optical device consists of a He-Ne laser which is shone on a surface. The scattered light is captured by a semicircular array of 87 detector elements rotated over the scanned area. The light signals are processed through a digital voltmeter and then an A/D converter. The signals are then stored for later comparisons with optical scattering data obtained by optical instruments used with stylus instruments for characterizing surface topographies. A theoretical model has been defined which relates light scattering and the characteristics of the surface roughness. Initial experimental results with a sinusoidal surface have indicated that although the system can follow the trend of the roughness, the roughness amplitude is as yet uncertainly defined and the computations require excessive time.

Optical Roughness Measurements Of Industrial Surfaces

Proceedings of SPIE, Oct 23, 1986

This paper reviews our efforts to develop the theory and instrumentation needed to measure surfac... more This paper reviews our efforts to develop the theory and instrumentation needed to measure surface roughness of manufactured surfaces by optical scattering methods. We are addressing three key problems: developing a valid and sufficient optical scattering theory for this roughness range, applying appropriate mathematical inversion techniques so that practical roughness parameters can be calculated from scattering distributions, and finally evaluating a compact commercial instrument for a wide variety of problems. Recent results from our group suggest that the simple phase screen approximation model of optical scattering validly describes light scattering from machined metal surfaces with a predominant surface lay in the 0.01 pm R to 3.0 pm R range. A model for scattering in the entire farr-field hemisphere and obsera vations on our r approach to the inverse problem is given.

Electronic limitations in phase meters for heterodyne interferometry

Precision Engineering-journal of The International Societies for Precision Engineering and Nanotechnology, Jul 1, 1993

Limitations imposed by the phase meters used in heterodyne interferometers are evaluated. These i... more Limitations imposed by the phase meters used in heterodyne interferometers are evaluated. These instruments measure the phase relationship between electrical signals generated by the heterodyning process, allowing the interferometers to resolve fractions of an optical fringe. Measurements indicate that the phase meters used in currently available heterodyne interferometers probably limit achievable accuracy to a greater extent than barriers imposed by the optics. We show that a new class of time interval counters offers a means of greatly improving accuracy in these instruments.

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Electric Power Grounding and Conditioning

Springer eBooks, 2015

Minimization of electrical noise is a critical factor in the design and construction of all sensi... more Minimization of electrical noise is a critical factor in the design and construction of all sensitive electrical instruments. This chapter addresses two important sources of electrical noise commonly found in laboratory equipment and hardware, and methods for their minimization. First, electrical noise generated from improper grounding of system components and associated hardware. Appropriate National Electrical Code is referenced for such terms as grounding conductors, grounded conductors, equipment grounding conductors and grounding electrode systems. Basic grounding requirements for every facility and a methodology for reducing electrical interference in facility design are provided. Second, common problems arising because of the instability of power source voltages, means to measure these power source variations and how they can be prevented by applying power conditioning devices to critical circuitry are described.

Electrical test structure and method for measuring the relative locations of conducting features on an insulating substrate

Method of and articles for accurately determining relative positions of lithographic artifacts

Piezodriven 50-�m range stage with subnanometer resolution

Electrical test structure and method for measuring the relative locations of conductive features on an insulating substrate

Disturbances due to Building Mechanical Systems

Science policy reports, 2015

Today’s advanced technology buildings require extensive mechanical equipment for building heating... more Today’s advanced technology buildings require extensive mechanical equipment for building heating, cooling, ventilation, and filtration. The challenge is to design, construct, and maintain an environment that is relatively quiet and relatively free of vibration, both for research personnel, research equipment, and neighboring facilities. Reduced thresholds for both noise and vibration levels from all sources, including systems effects such as flow turbulence in ducts and air inlets have required that every aspect of building mechanical systems be carefully studied and designed to minimize such effects. This chapter addresses the vibration and noise induced by building mechanical systems and presents several cases in which these problems were solved.

Nanoscience Research for Energy Needs. Report of the National Nanotechnology Initiative Grand Challenge Workshop, March 16-18, 2004

On behalf of the NSET Subcommittee, we wish to thank Drs. Robert Hwang and Ellen Williams for the... more On behalf of the NSET Subcommittee, we wish to thank Drs. Robert Hwang and Ellen Williams for their creativity and hard work in conducting an outstanding workshop and in preparing this report. We also thank all the speakers, session chairs, and participants for their time and efforts to join the workshop and to make their individual contributions to the discussions at the workshop and then to draft this report. Their generous sharing of their research results and their insights ensures that this document will serve as a reference for the NNI.

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