Принципы нанометрологии (Раздаточные материалы от преподавателя), страница 7

However, this book will concentrate onthe more traditional dimensional and mass areas. This choice is partly tokeep the scope of the book at a manageable level and partly because those arethe areas of research that the author has been active in.So, engineering nanometrology is traditional engineering metrology at theMNTscale.

Note that whilst nanotechnology is the science and technology ofstructures varying in size from around 0.1 nm to 100 nm, nanometrologydoes not only cover this size range. Nanometrology relates to measurementswith accuracies or uncertainties in this size range (and smaller!). Forexample, one may be measuring the form of a 1 m telescope mirror segmentto an accuracy of 10 nm.It is important to realise that there are many areas of MNT measurementthat are equally as important as dimensional and mass measurements.

Otherareas not included in this book are measurements of electrical, chemical andbiological quantities, and the wealth of measurements for material properties, including the properties of particles. There are also areas of metrologythat could well be considered engineering nanometrology but have not beencovered by this book. These include the measurement of roundness [11], thinfilms (primarily thickness) [12,13], the dynamic measurement of vibratingstructures [14] and tomography measurements (primarily x-ray computedtomography [15] and optical coherence tomography [16]). Once again, thechoice of contents has been dubiously justified above!1.2 The contents of this bookThis book is divided into ten chapters.

Chapter 2 gives an introduction tomeasurement, including short histories of, and the current unit definitionsfor, length, angle, mass and force. Basic metrological terminology is introduced, including the highly important topic of measurement uncertainty.The laser is presented in chapter 2, as it is a very significant element of manyof the instruments described in this book.Chapter 3 reviews the most important concepts needed when designingor analysing precision instruments.

Chapter 4 covers the measurement oflength using optical interferometry, and discusses the concepts behindinterferometry, including many error sources. Chapter 5 reviews the area ofdisplacement measurement and presents most modern forms of displacement sensor. The field of surface texture measurement is covered in the next34C H A P T ER 1 : Introduction to metrology for micro- and nanotechnologythree chapters, as it is a very large and significant topic. Chapter 6 coversstylus and optical surface measuring instruments, and chapter 7 coversscanning probe and particle beam instruments. Both chapters 6 and 7 includeinstrument descriptions, limitations and calibration methods.

Chapter 8presents methods for characterizing surfaces, including both profile and arealtechniques. Chapter 9 introduces the area of coordinate metrology andreviews the latest developments with micro-coordinate measuring machines.Lastly, chapter 10 presents a review of the latest advances in low mass andforce metrology.1.3 References[1] Storrs Hall J 2005 Nanofuture: what’s next for nanotechnology (PromethiusBooks)[2] Mulhall D 2002 Our molecular future: how nanotechnology, robotics,genetics and artificial intelligence will transform our future (PromethiusBooks)[3] 2004 Nanoscience and nanotechnologies: opportunities and uncertainties(Royal Society and Royal Academy of Engineering)[4] Singleton L, Leach R K, Cui Z 2003 Analysis of the MEMSTAND survey onstandardisation for microsystems technology Proc.

Int. Seminar MEMSTAND, Barcelona, Spain, 24-26 Feb. 11–31[5] MEMS Industry Group Report: ‘‘Focus on Fabrication,’’ Feb. 2003[6] Postek M T, Lyons K 2007 Instrumentation, metrology and standards:key elements for the future of nanotechnology Proc. SPIE 6648 664802[7] Hunt G, Mehta M 2008 Nanotechnology: risk, ethics and law (EarthscanLtd)[8] Hume K J 1967 Engineering metrology (Macdonald & Co.) 2nd edition[9] Thomas G G 1974 Engineering metrology (Newnes-Butterworth: London)[10] Anthony D M 1986 Engineering metrology (materials engineering practice)(Pergamon)[11] Smith G T 2002 Industrial metrology: surfaces and roundness (Springer)[12] Tompkins H G, Eugene A I 2004 Handbook of ellipsometry (Springer)[13] Yacoot A, Leach R K 2007 Review of x-ray and optical thin film measurementmethods and transfer artefacts NPL Report DEPC-EM 13[14] Lobontiu N 2007 Dynamics of microelectromechanical systems (Springer)[15] Withers P J 2007 X-ray nanotomography Materials Today 10 26–34[16] Brezinski M E 2006 Optical coherence tomography: principles and applications (Academic Press)CHAPTER 2Some basics of measurement2.1 Introduction to measurementOver the last couple of thousand years significant advances in technology canbe traced to improved measurements.

Whether we are admiring the engineering feat represented by the Egyptian pyramids, or the fact that in thetwentieth century humans walked on the moon, we should appreciate thatthis progress is due in no small part to the evolution of measurement. It issobering to realise that tens of thousands of people were involved in bothoperations and that these people were working in many different placesproducing various components that had to be brought together – a large partof the technology that enabled this was the measurement techniques andstandards that were used [1].The Egyptians used a royal cubit as the standard of length measurement(it was the distance from Pharaoh’s elbow to his fingertips – see Figure 2.1),while the Apollo space programme ultimately relied on the definition of themetre in terms of the wavelength of krypton 86 radiation.In Egypt the standards were kept in temples and the priests werebeheaded if they were not recalibrated on time.

Nowadays there areworldwide systems of accrediting laboratories, and laboratories are threatened with losing their accreditation if the working standards are not recalibrated on time. Primary standards are kept in national measurementinstitutes that have a great deal of status and national pride.

The Egyptiansappreciated that, provided that all four sides of a square are the samelength and the two diagonals are equal, then the interior angles will all bethe same – 90 . They were able to compare the two diagonals and look forsmall differences between the two measurements to determine how squarethe base of the pyramid was.Humans have walked on the moon because a few brave people wereprepared to sit on top of a collection of ten thousand manufactured parts allFundamental Principles of Engineering NanometrologyCopyright Ó 2010 by Elsevier Inc. All rights reserved.CONTENTSIntroduction tomeasurementUnits of measurementand the SILengthMassForceAngleTraceabilityAccuracy, precision,resolution, error anduncertaintyThe laserReferences56C H A P T ER 2 : Some basics of measurementFIGURE 2.1 An ancient Egyptian cubit (a standard of mass is also shown).built and assembled by the lowest bidder, and finally filled with hundreds oftons of explosive hydrogen and oxygen propellant.

A principal reason that it alloperated as intended was that the individual components were manufacturedto exacting tolerances that permitted final assembly and operation as intended.The phrase ‘mass production’ these days brings visions of hundreds ofcars rolling off a production line every day. From Henry Ford in the 1920sthrough to the modern car plants such as BMW and Honda, the key to thisapproach is to have tiers of suppliers and sub-contractors all sending the rightparts to the next higher tier and finally to the assembly line. The wholemanufacture and assembly process is enabled by the vital traceablemeasurements that take place along the route.Modern manufacturing often involves the miniaturization of productsand components. This ‘nanotechnology revolution’ has meant that not onlyhave the parts shrunk to micrometres and nanometres, but tolerances havetoo.

The dimensional and mass measurements that are required to ensurethat these tiny parts fit together, or ensure that larger precision parts are fit forpurpose, are the subject of this book.2.2 Units of measurement and the SIThe language of measurement that is universally used in science and engineering is the Système International d’Unités (SI) [2]. The SI embodies theLengthmodern metric system of measurement and was established in 1960 by the11th Conférence Générale des Poids et Mesures (CGPM). The CGPM is theinternational body that ensures wide dissemination of the SI and modifiesthe SI as necessary to reflect the latest advances in science and technology.There are a number of international organizations, treaties and laboratoriesthat form the scientific and legal infrastructure of measurement (see [3] fordetails).

Most technologically advanced nations have national measurementinstitutes (NMIs) that are responsible for ensuring that measurementscomply with the SI and ensure traceability (see section 2.7). Examples ofNMIs include the National Physical Laboratory (NPL, UK), PhysikalischTechnische Bundesanhalt (PTB, Germany), National Metrology InstituteJapan (NMIJ, Japan) and the National Institute of Standards and Technology(NIST, USA). The web sites of the larger NMIs all have a wealth of information on measurement and related topics.The SI is principally based on a system of base quantities, each associatedwith a unit and a realization.

A unit is defined as a particular physical quantity,defined and adopted by convention, with which other particular quantitiesof the same kind are compared to express their value. The realization of a unitis the physical embodiment of that unit, which is usually performed at anNMI. The seven base quantities (with their associated units in parentheses)are: time (second), length (metre), mass (kilogram), electric current (ampere),thermodynamic temperature (kelvin), amount of substance (mole) andluminous intensity (candela). Engineering metrology is mainly concernedwith length and mass, and these two base quantities will be given someattention here.

Force and angle are also important quantities in engineeringmetrology and will be discussed in this chapter. The other base quantities, andtheir associated units and realizations, are presented in Appendix 1.In addition to the seven base quantities there are a number of derivedquantities that are essentially combinations of the base units. Some examples include acceleration (unit: metres per second), density (unit: kilogramper cubic metre) and magnetic field strength (unit: ampere per metre).

Thereare also a number of derived quantities that have units with special names.Some examples include frequency (unit: hertz or cycles per second), energy(unit: joule or kilogram per square metre per second) and electric charge (unit:coulomb or the product of ampere and second). Further examples of derivedunits are presented in Appendix 2.2.3 LengthThe definition and measurement of length has taken many formsthroughout human history (see [4,5] for more thorough historical overviews).78C H A P T ER 2 : Some basics of measurementThe metre was first defined in 1791, as ‘one ten millionth of the polarquadrant of the earth passing through Paris’.