Precision positioning of an object relative to a reference point is a common task in many activities of production engineering. Sensor technologies for single axis measurement, either linear or rotary, which form the fundamentals of measurement technologies for precision positioning, are reviewed. Multi-axis coordinate measurement methods such as triangulation and multilateration, as well as Cartesian and polar systems for specifying the position in a plane or three-dimensional (3D) space are then presented, followed by a discussion on traceability and standards. Some advanced applications of measurement technologies for precision positioning in manufacturing industries are also demonstrated.

Measurement technologies for precision positioning

Atomic and subnanometer resolution in ambient conditions by atomic force microscopy

Gallium nitride (GaN) light-emitting-diode (LED) technology has been the revolution in modern lighting. In the last decade, a huge global market of efficient, long-lasting, and ubiquitous white light sources has developed around the inception of the Nobel-prize-winning blue GaN LEDs. Today, GaN optoelectronics is developing beyond solid-state lighting, leading to new and innovative devices, e.g., for microdisplays, being the core technology for future augmented reality and visualization, as well as point light sources for optical excitation in communications, imaging, and sensing. This explosion of applications is driven by two main directions: the ability to produce very small GaN LEDs (micro-LEDs and nano-LEDs) with high efficiency and across large areas, in combination with the possibility to merge optoelectronic-grade GaN micro-LEDs with silicon microelectronics in a hybrid approach. GaN LED technology is now even spreading into the realm of display technology, which has been occupied by organic LEDs and liquid crystal displays for decades. In this review, the technological transition toward GaN micro- and nanodevices beyond lighting is discussed including an up-to-date overview on the state of the art.

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Beyond solid-state lighting: Miniaturization, hybrid integration, and applications of GaN nano- and micro-LEDs

Design of hysteresis-compensating iterative learning control for piezo-positioners: Application to atomic force microscopes

The review will describe the various scanning probe microscopy tips and cantilevers used today for scanning force microscopy and magnetic force microscopy. Work undertaken to quantify the properties of cantilevers and tips, e.g. shape and radius, is reviewed together with an overview of the various tip–sample interactions that affect dimensional measurements.

https://iopscience.iop.org/article/10.1088/0022-3727/41/10/103001/pdf

Aspects of scanning force microscope probes and their effects on dimensional measurement

We describe a metrological large range scanning probe microscope (LR-SPM) with an Abbe error free design and direct interferometric position measurement capability, aimed at versatile traceable topographic measurements that require nanometer accuracy. A dual-stage positioning system was designed to achieve both a large measurement range and a high measurement speed. This dual-stage system consists of a commercially available stage, referred to as nanomeasuring machine (NMM), with a motion range of 25 mm×25 mm×5 mm along x, y, and z axes, and a compact z-axis piezoelectric positioning stage (compact z stage) with an extension range of 2 μm. The metrological LR-SPM described here senses the surface using a stationary fixed scanning force microscope (SFM) head working in contact mode. During operation, lateral scanning of the sample is performed solely by the NMM. Whereas the z motion, controlled by the SFM signal, is carried out by a combination of the NMM and the compact z stage. In this case the compact z...

Metrological large range scanning probe microscope

Accurate and traceable calibration of lateral standards (1D and 2D gratings) is a basic metrological task for nano- and microtechnology. Both the mean pitch and the uniformity of the gratings should be measured quantitatively. Although optical diffractometers are effective for measuring the mean pitch, they are not able to measure the uniformity of gratings. In this study, the calibration of gratings is performed using a metrological large range scanning probe microscope with optimized measurement strategies. Two different kinds of data evaluation methods, a gravity centre method and a Fourier transform method, have been developed and investigated. Cosine error, a significant error source of the measurement, is analysed and corrected. Calibrations on several 1D gratings have been carried out. The calibrated mean pitch values have an excellent agreement with those measured by optical diffractometry. Nevertheless, irregularities of the gratings were only deduced from the SPM results. Finally, the usage of the 1D/2D gratings for the calibration of a typical SPM is illustrated.

https://iopscience.iop.org/article/10.1088/0957-0233/18/2/S13/pdf

Accurate and traceable calibration of two-dimensional gratings

An approach to establishing rigorous nano- and microdimensional metrology using scanning probe microscopes (SPMs) and metrological profilometers is presented. An overview on calibrations of nanostructures—such as step height, one- and two-dimensional gratings, feature width, nanoroughness and geometry of a nanohardness indenter—and microstructures—such as microgroove, microroughness and geometry of a macrohardness indenter—is given in this paper.

https://iopscience.iop.org/article/10.1088/0957-0233/17/3/S15/pdf

Accurate and traceable measurement of nano- and microstructures

A method for direct and non-destructive sidewall scanning of nano- and micro-structures is presented. The measurements are performed with a kind of novel 'assembled cantilever probe (ACP)'. Such ACPs consist of four parts: substrate, cantilever, extension(s) and probe tip(s). The tip(s) located at the free end of the extension may extend horizontally. As a benefit, the ACPs are capable of probing in a direction perpendicular to sidewalls. The bending, torsion or deformation of the cantilever is detected when the tip is brought into contact, intermittent contact or non-contact, with sidewalls. Investigations show that the ACPs have a low measurement noise at a subnanometre level. Measurement examples performed at the sidewalls of microtrenches, microgears and line edge roughness samples are given in this paper.

https://iopscience.iop.org/article/10.1088/0957-0233/18/2/S03/pdf

Nanoscale surface measurements at sidewalls of nano- and micro-structures

In this paper, a self-calibration method has been employed for mapping the errors in the xy-plane and the squareness error between the z-axis and xy-plane of the SPMs. The self-calibration method has advantages such as a rather simple calibration setup, being capable of extracting both artefact-related and SPM-related errors, and a high calibration performance limited only by the stability of the instruments. Two commercial SPMs have been investigated using the proposed method. The obtained results agree well with those obtained from classical calibration methods by means of highly accurate transfer standards and metrological devices. The self-calibration method could be a kind of effective complementary method for mapping more errors of SPMs.

https://iopscience.iop.org/article/10.1088/0957-0233/19/2/025105/pdf

Min Xu

Papers

Metrological large range scanning probe microscope

Accurate and traceable calibration of two-dimensional gratings

Accurate and traceable measurement of nano- and microstructures

Nanoscale surface measurements at sidewalls of nano- and micro-structures

Self-calibration of scanning probe microscope: mapping the errors of the instrument