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An Assessment of the National Institute of Standards and Technology Manufacturing Engineering Laboratory: Fiscal Year 2010 5 Precision Engineering Division The Precision Engineering Division delivers to industry important length-related measurements, standards, and technology services that directly support the products and processes of U.S. manufacturing. These standards are measured by a whole array of instrumentation ranging from atomic force microscopes to conventional and frameless coordinate measuring machines using contact, particle beam, and optical measuring probes, machines, and systems. Features of interest range in size from 1 kilometer (calibrated telecommunication cables) to meters (laser trackers) to nanometers (critical-dimension [CD] metrology instruments and nanoparticle dimensional metrology). Modeling capabilities and methods are being developed together with experimental measurement technologies, and these are used jointly to address next-generation problems. For example, the code for modeling AFM data is now widely used in the industry. A new version, Java Monte-Carlo Simulator for Secondary Electrons (JMONSEL), of the widely used NIST code MONSEL is being developed for three-dimensional scanning electron microscopy (SEM). Consistent with NIST policy, codes are made freely available to the technical community. The PED currently has 35 NIST staff, 22 guest researchers (full-time-equivalent), and 1 postdoctoral researcher. Its FY 2010 estimated funding is about $12.7 million, with about 23 percent coming from extramural sources. TECHNICAL MERIT RELATIVE TO STATE OF THE ART Essentially all of the PED’s programs reviewed for this assessment push the state of the art in their areas. These programs are well connected to NIST objectives and to the needs of the industrial and scientific communities. The PED’s leaders are internationally recognized within their fields, and they provide excellent technical leadership within their areas of expertise. The PED recognizes that one of its primary roles is to maintain metrology standards. Toward this end, the division has developed a nanowriting capability using an atomically sharp tip (whose shape can be determined and modified accordingly), which will generate badly needed standards for dimensions on the order of a few atoms that are traceable to NIST. This capability will be critically important at the 22 nm node and beyond in integrated-circuit (IC) technology. Regarding metrology, the PED is developing a calibrated atomic force microscope (C-AFM) that is already returning line roughness measurements that will also be crucial for 22 nm lithography and beyond. Also important for metrology, the PED is developing step-height standards for calibrating AFMs. Its helium-ion microscopy is state of the art and gives the PED new capabilities in dimensional analysis. The 65 m laser-tracker test-range distance metrology project represents an important project that currently only NIST can do. The objective is to allow measurements made in air to be referenced to the standard meter to within parts in 107 by accurately measuring, then compensating for, pressure and temperature variations. This is
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An Assessment of the National Institute of Standards and Technology Manufacturing Engineering Laboratory: Fiscal Year 2010 done by a creative use of frequency combs to transfer the standard meter to the laser wavelength through Global Positioning System (GPS) timing, then to use the laser wavelength as the secondary standard for the actual measurement. The project has already achieved a capability of 5 parts in 107. ADEQUACY OF INFRASTRUCTURE The move to the Advanced Measurement Laboratory has provided best-in-the-world facilities for equipment that in many cases is the most advanced available anywhere. The quality of the AML facilities has translated into instrument performance that routinely provides fundamental limits independent of environmental effects. Equipment availability in the PED is good, but the acquisition of equipment appears to be limited and overly reliant on fortuitous connections between PED personnel and outside organizations. The PED has been very creative in benefiting from these connections in that collaborators and customers have made equipment available at good prices. One example is the Moore M48 CMM that was brought in from the Sandia National Laboratories. The PED is an equipment-intensive division, yet it does not appear to have a regular program for the acquisition of critical equipment needed to maintain its technical capabilities. ACHIEVEMENT OF OBJECTIVES AND IMPACT Dimensional metrology is advancing well, with existing capabilities being driven to new levels and new capabilities coming online. The JMONSEL modeling code for SEM imaging is a case in point, anticipating the needs for future IC technology, in which devices will be using the third dimension. A further example of anticipating future needs in IC technology is the C-AFM project, with the objective of providing accurate measurements of linewidths, pitch, and sidewall roughness, all of which will become critical at the 22 nm node and beyond. Division members continue to receive awards and recognition—for example, the Nano-50 Award for Scatterfield Microscopy, the Department of Commerce Gold Medal for Leadership in International Standards, and two Department of Commerce Silver Awards: one for the development of optical methods in overlay and the other for the NIST microfeature CMM probe. Two members were elected fellows of SPIE. One paper (on removing tip-shape from scanning probe microscope images) by PED staff has been cited 187 times at last count, which is an unusually large number in a fast-moving field where publications in conference proceedings are more common, and many of these have a short lifetime. In addition to the Department of Commerce, the PED provides services to the National Aeronautics and Space Administration; the Bureau of Alcohol, Tobacco, and Firearms; the Federal Bureau of Investigation; the Department of Energy; the Bethesda Naval Medical Center; and other government entities such as the U.S. Army. One concern is the reliance of the PED on contractors rather than on permanent staff. The PED is to be commended for its creativity in making budgets stretch, but that is not likely to be a long-term solution. One of the major advantages of NIST relative to other organizations is institutional memory—that is, the continuity provided by experts
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An Assessment of the National Institute of Standards and Technology Manufacturing Engineering Laboratory: Fiscal Year 2010 who have become very good at operating the specialized equipment that allows NIST to fulfill its role. Excessive reliance on contractors negates this advantage. Over the past decade, PED staff have played an active role in the development of American Society of Mechanical Engineers (ASME) standards as well ISO standards. ISO standards are widely used, although U.S. standards are technically superior. The MEL leads an international task force to improve the rigor of the ISO CMM standard and also chairs the effort to harmonize the U.S. and ISO CMM standards. Unifying U.S. and ISO CMM standards reduces barriers to trade by enabling internationally based supply chains, clarifying contractual requirements, and eliminating redundant procedures and training. PED contributions have included the following: ASME B220.127.116.11-2001: Guidelines for Decision Rules: Considering Measurement Uncertainty in Determining Conformance to Specifications ASME B18.104.22.168-2002: Guidelines for Assessing the Reliability of Dimensional Measurement Uncertainty Statements ASME B89.4.22-2004: Methods for Performance Evaluation of Articulated Arm Coordinate Measuring Machines ASME B22.214.171.124-2005 (technical report): Measurement Uncertainty and Conformance Testing: Risk Analysis ASME B89.7.5-2006: Metrological Traceability of Dimensional Measurements to the SI Unit of Length ASME B89.4.19-2006: Performance Evaluation of Laser-Based Spherical Coordinate Measurement Systems ASME B126.96.36.199-2007: (technical report): Guidelines for the Evaluation of Dimensional Measurement Uncertainty ASME B89.4.10360.2-2008: Acceptance Test and Reverification Test for Coordinate Measuring Machines (CMMs), Part 2: CMMs Used for Measuring Linear Dimensions An MEL report7 (published in 2007) was cited heavily in the National Research Council report on ballistic imaging.8 CONCLUSIONS Following are the conclusions of the panel based on its assessment of the Precision Engineering Division: The PED research staff is knowledgeable, enthusiastic about what they are doing, and committed to excellence. They strive to maintain relevance by 7 T.V. Vorburger, J.H. Yen, B. Bachrach, T.B. Renegar, J.J. Filliben, L. Ma, H.-G. Rhee, A. Zheng, J.-F. Song, M. Riley, C.D. Foreman, and S.M. Ballou, Surface Topography Analysis for a Feasibility Assessment of a National Ballistics Imaging Database, NISTIR 7362, Gaithersburg, Maryland: National Institute of Standards and Technology, May 2007. 8 National Research Council, Ballistic Imaging, edited by Daniel L. Clark, John E. Ralph, Eugene S. Meieran, and Carol V. Petrie, Washington, D.C.: The National Academies Press, 2008.
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An Assessment of the National Institute of Standards and Technology Manufacturing Engineering Laboratory: Fiscal Year 2010 remaining in contact with key industrial constituencies, such as SEMATECH, and focus on topical areas and projects that are likely to become important in the future. The PED staff do well working with what they have. Laboratory facilities are very good, with available equipment generally being state of the art, often unique. Even though they may be decades old, facilities are maintained in top condition and are operated by experts. Consistent with the general NIST philosophy, this institutional expertise is a national resource. The PED interface with the outside world is outstanding. Its staff participates in relevant meetings, which not only aids their goals of disseminating information to industry but also keeps PED personnel updated and attuned to customer needs. PED impact is clearly significant. This is evidenced in many ways—for example, by the large number of ongoing collaborations with companies. The number of requests for services far exceeds the capacity of the division to meet them. Other measures include the number of citations for PED staff publications, and the division’s ability to acquire equipment, either donated or purchased at bargain prices. The PED is to be commended for handling the many demands on its time by appropriate triaging—for example, routing routine requests for gage-block metrology to commercial vendors. The PED’s coordinate-measurement and uncertainty expertise is unique and not likely to be duplicated anywhere else. This expertise was critical in its recent work contributing to the U.S. Army’s resolution of an issue involving large, body-armor contracts. The PED appreciates that one of its roles is to maintain metrology. Its state-of-the-art atomically sharp tip nanowriting capability will, among other applications, be used to generate badly needed standards for dimensions on the order of a few atoms that are traceable to NIST. Some semiconductor CD metrology work is not state of the art owing to the approaches being used. However, this can probably be justified as investigating ways of taking metrology in new directions. The acquisition of relevant equipment in 2010 will eliminate this concern. The PED works toward positioning itself to the future. In particular, it concentrates on projects that are expected to be important in the near-term future. These include nanometrology, improving optical resolution, better sensors, and establishing metrology standards for fuel cell catalysts. At the same time it has dropped projects best handled elsewhere, such as sieve standards and civil engineering metrology now done more conveniently by GPS. The planned equipment allotment from the American Recovery and Reinvestment Act of 2009 (Public Law 111-5) is a welcome development. The PED should continue its participation in regional and international round robins as a key benchmarking exercise. The budget available for capital acquisitions is inadequate for such a capital-intensive division.
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An Assessment of the National Institute of Standards and Technology Manufacturing Engineering Laboratory: Fiscal Year 2010 The PED could benefit from stronger interfaces with other areas of NIST. The panel heard little concerning the natural interfaces that should occur—for example, between the PED and NIST’s Center for Nanoscale Science and Technology and Physics Laboratory. PED management needs to develop and implement a critical-skills staffing plan independent of future budget developments so that its critical expertise within NIST is maintained. At present there is too much dependence on guest workers, which appears to be as a direct consequence of flat long-term funding.