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79–86[116] Leach R K 1999 Calibration, traceability and uncertainty issues in surfacetexture metrology NPL Report CLM7[117] Krüger-Sehm R, Krystek M 2000 Uncertainty analysis of roughnessmeasurement Proc. X Int. Colloq. Surfaces, Chemnitz, Germany, Jan./Feb.(in additional papers)[118] Giusca C, Forbes A B, Leach R K 2009 A virtual machine-based uncertaintyevaluation for a traceable areal surface texture measuring instrument Rev.Sci. Instrum.
submitted[119] Leach R K 2004 Some issues of traceability in the field of surface texturemeasurement Wear 257 1246–1249[120] ISO 5436 part 1: 2000 Geometrical product specification (GPS) - Surfacetexture: Profile method - Measurement standards - Part 1 Materialmeasures (International Organization of Standardization)[121] Leach R K, Cross N 2002 Low-cost traceable dynamic calibration of surfacetexture measuring instruments Meas. Sci. Technol. 14 N1–N4[122] ISO 12179: 2000 Geometrical product specification (GPS) - Surface texture:profile method - Calibration of contact (stylus) instruments (InternationalOrganization for Standardization)[123] ISO/FDIS 25178 part 701: 2007 Geometrical product specification (GPS) Surface texture: Areal - Calibration and measurement standards for contact(stylus) instruments (International Organization of Standardization)[124] Haycocks J, Jackson K, Leach R K, Garratt J, MacDonnell I, Rubert P, Lamb J,Wheeler S 2004 Tackling the challenge of traceable surface texture measurement in three dimensions Proc.
5th Int. euspen Conf., Turin, Italy, May 253–256References[125] Leach R K, Chetwynd D G, Blunt L A, Haycocks J, Harris P M, Jackson K,Oldfield S, Reilly S 2006 Recent advances in traceable nanoscale dimensionand force metrology in the UK Meas. Sci. Technol. 17 467–476[126] Krystek M 2000 Measurement uncertainty propagation in the case offiltering in roughness measurement Meas. Sci. Technol. 12 63–67[127] Morel M A A, Haitjema H 2001 Calculation of 3D roughness measurementuncertainty with virtual surfaces Proc. IMEKO, Cairo, Egypt 1–5[128] Haitjema H, Morel M 2000 Traceable roughness measurements of productsProc.
1st euspen Conf. on Fabrication and Metrology in Nanotechnology,Denmark 354–357[129] Haitjema H, Morel M 2000 The concept of a virtual roughness tester Proc.X Int. Colloq. Surfaces, Chemnitz, Germany, Jan./Feb. 239–244[130] Haitjema H 1997 International comparison of depth-setting standardsMetrologia 34 161–167[131] Leach R K, Hart A 2002 A comparison of stylus and optical methods formeasuring 2D surface texture NPL Report CBTLM 15[132] Koenders L, Andreasen J L, De Chiffre L, Jung L, Krüger-Sehm R 2004EUROMET L.S11 Comparison on surface texture Metrologia 41 04001[133] Vorburger T V, Rhee H-G, Renegar T B, Song J-F, Zheng A 2008Comparison of optical and stylus methods for measurement of surfacetexture Int.
J. Adv. Manuf. Technol. 33 110–118[134] ISO 5436 part 2: 2000 Geometrical product specification (GPS) - Surfacetexture: Profile method - Measurement standards - Part 2 Softwaremeasurement standards (International Organization of Standardization)[135] ISO/FDIS 25178 part 7: Geometrical product specification (GPS) - Surfacetexture: Areal - Software measurement standards (International Organization of Standardization)[136] Blunt L, Jiang X, Leach R K, Harris P M, Scott P 2008 The development ofuser-friendly software measurement standards for surface topographysoftware assessment Wear 264 389–393[137] Bui S, Vorburger T V 2006 Surface metrology algorithm testing systemPrecision Engineering 31 218–225[138] Jung L, Spranger B, Krüger-Sehm R, Krystek M 2004 Reference software forroughness analysis - features and results Proc. XI Int.
Colloq. Surfaces,Chemnitz, Germany, Feb. 164–170175This page intentionally left blankCHAPTER 7Scanning probe and particlebeam microscopyDr. Alexandre CuenatNational Physical LaboratoryAs technology moves deeper into the realm of the microscopic bymanufacturing smaller components, it becomes essential to measure ata suitable scale and resolution.
This scale is in the nanometre range and theresolution expected is of the order of atomic distances or even smaller. In thelate seventeenth century, the development of optical microscopes enabledscientists to observe structure on the scale of micrometres. Until thetwentieth century, the optical microscope was the fundamental instrumentthat enabled progress in materials and biological sciences. However, theobservation of single atoms requires far more resolution than visible light canprovide.In the beginning of the twentieth century, the electron microscope wasdeveloped based on the newly discovered wave-like properties of the electron.Indeed, electrons with sufficient energy will have a wavelength comparable tothe diameter of an atom or smaller.
Unfortunately, electron optics limit theresolution that an electron microscope can reach and true atom-by-atomresolution is far from routine.A study of surface atoms is even more challenging and requires a differenttype of probe. Indeed, high-energy electrons will penetrate into the bulkmaterial without providing surface information, and low-energy electronswill be scattered by the surface. For many years, scientists have useddiffraction phenomena to study the atomic ordering at surfaces, but thelateral resolution is still of the order of a micrometre.The development of the scanning tunnelling microscope (STM) by GerdBinnig and Heinrich Rohrer in 1982 [1] was a major tool in the development of a new field of human endeavour – nanotechnology. The STMenabled the next step in imaging and probing technology.
The STM mayFundamental Principles of Engineering NanometrologyCopyright Ó 2010 by Elsevier Inc. All rights reserved.CONTENTSScanning probemicroscopyScanning tunnellingmicroscopyAtomic forcemicroscopyScanning probemicroscopy ofnanoparticlesElectron microscopyOther particle beammicroscopy techniquesReferences177178C H A P T ER 7 : Scanning probe and particle beam microscopynot have been the first scanning probe system, but the atomic resolution itdemonstrated captured the imagination of the scientific community. Sincethen, a series of near-field methods have been developed, capable ofprobing or imaging many physical or chemical properties with nanometrescale resolution. All these new microscopes are based on the same principle: a very sharp tip, with a radius typically of a few nanometres, isscanned in close proximity to a surface using a piezoelectric scanner.
Thevery localised detection of forces in the near-field is in marked contrastwith previous instruments, which detected forces over much larger areas orused far-field wave phenomena. This chapter reviews the principalmethods that have been developed to measure properties at the atomic tonanometre scale and the related metrology challenges, with a particularfocus on the atomic force microscope (AFM). The reason for this choice isthat the AFM is by far the most popular instrument to date and is themost likely candidate to be fully traceable – including force – in the nearfuture.
Electron microscopes, scanning and transmission, are also includedin this chapter as they are capable of giving information in the same rangeand are also very popular. The chapter concludes with a few words on thefocused ion beam microscope and the newly developed helium beammicroscope.7.1 Scanning probe microscopyScanning probe microscopes (SPMs) are increasingly used as quantitativemeasuring instruments not only for dimensions, but also for physical andchemical properties at the nanoscale (see [2,3] for thorough introductions toSPM technology). Furthermore, SPM has recently entered the production andquality-control environment of semiconductor manufacturers.
However, forthese relatively new instruments, standardized calibration procedures stillneed to be developed.From an instrumentation perspective, the SPM is a serial measurementdevice, which uses a nanoscale probe to trace the surface of the sample basedon local physical interactions (in a similar manner to a stylus instrument –see section 6.6.1). While the probe scans the sample with a predefinedpattern, the signal of the interaction is recorded and is usually used to controlthe distance between the probe and the sample surface.
This feedbackmechanism and the scanning of a nanoscale probe form the basis of allscanning probe instruments. Figure 7.1 shows an example schema of anAFM. A sample is positioned on a piezoelectric scanner, which moves thesample in three dimensions relative to a transduction mechanism (in thisScanning probe microscopyFIGURE 7.1 Schematic image of a typical scanning probe system, in this case an AFM.case a flexible mechanical cantilever) with a very sharp tip in very closeproximity to the sample.Depending on the physical interactions used to probe the surface, thesystem can have different names, for example:-scanning tunnelling microscopes (STMs) are based on the quantummechanical tunnelling effect (see section 7.2);-atomic force microscopes (AFMs) use interatomic or intermolecularforces (see section 7.3);-scanning near-field optical microscopes (SNOMs) probe the surfaceusing near-field optics (sometimes referred to a electromagnetictunnelling) (see [2,4]).Many more examples of SPMs have been developed that use almost everyknown physical force, including: electrostatic, magnetic, capacitive, chemical and thermal.
For each instrument, various modes of operation arepossible. The most common modes used in engineering nanometrology are:Contact mode: the probe is in permanent contact with the surface, i.e.usually a repulsive force between the tip and the sample is used as feedback tocontrol the distance between the tip and the sample.179180C H A P T ER 7 : Scanning probe and particle beam microscopyNon-contact mode: the probe oscillates slightly above the surface andinteractions with the sample surface forces modify the oscillation parameters. One of the oscillation parameters (amplitude, frequency or phase shift)is kept constant with the feedback loop.Intermittent mode: non-contact mode in which the probe oscillates witha high amplitude and touches the sample for a short time (often referred to astapping mode).7.2 Scanning tunnelling microscopyAs its name suggests, the scanning tunnelling microscope takes advantage ofthe quantum mechanical phenomenon of tunnelling.
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