Integration of an isotropic microprobe and a microenvironment into a conventional CMM
TL;DR: In this article, the IMT-PTB microprobe is combined with a uniquely designed microenvironment, which facilitates and improves the measurement of workpieces with submillimeter features.
Abstract: This paper describes the experimental verification of the novel IMT-PTB microprobe combined with a uniquely designed microenvironment. The microprobe consists of three silicon-based parallelograms stacked orthogonally, which leads to high isotropy. The probe tip deflections are detected in 3D with the help of piezoresistors placed in the parallelograms. The microenvironment facilitates and improves the measurement of workpieces with submillimeter features. The new microprobe and the microenvironment were integrated into a commercial coordinate measuring machine (CMM). To evaluate the microprobe performance, PTB produced and calibrated three reference objects: a cube, a sphere, and a microgear measurement standard. The differences between the calibration values and the measurement results obtained by the microprobe were in the sub-micrometer range. Furthermore, the microprobe was compared with the standard probing system of the gear measuring machine by measuring the reference objects with identical parameters. The results show the excellent performance of the micro probing system, thereby extending the capability of the CMM for high-precision measurements of complex workpieces at the microscale.
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TL;DR: In this paper , the surface-sensing principles of micro-probe systems were the focus, and the characteristics were reviewed, including the performance trends of individual microprobe system with different sensing principles.
Abstract: Micro-coordinate measuring machines (micro-CMMs) for measuring microcomponents require a probe system with a probe tip diameter of several tens to several hundreds of micrometers. Scale effects work for such a small probe tip, i.e., the probe tip tends to stick on the measurement surface via surface adhesion forces. These surface adhesion forces significantly deteriorate probing resolution or repeatability. Therefore, to realize micro-CMMs, many researchers have proposed microprobe systems that use various surface-sensing principles compared with conventional CMM probes. In this review, the surface-sensing principles of microprobe systems were the focus, and the characteristics were reviewed. First, the proposed microprobe systems were summarized, and the probe performance trends were identified. Then, the individual microprobe system with different sensing principles was described to clarify the performance of each sensing principle. By comprehensively summarizing multiple types of probe systems and discussing their characteristics, this study contributed to identifying the performance limitations of the proposed micro-probe system. Accordingly, the future development of micro-CMMs probes is discussed.
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TL;DR: In this paper , the state-of-the-art inspection methodologies compatible with high-aspect-ratio structures and their suitability for extracting three-dimensional surface data based on identified high aspect ratio structure types are presented.
Abstract: Non-destructive measurements of high aspect ratio microscale features, especially those with internal geometries such as micro-holes, remain a challenging metrology problem that is increasing in difficulty due to the increasing requirement for more complexity and higher tolerances in such structures. Additionally, there is a growing use of functional surface texturing for improving characteristics such as heat transfer and wettability. As a result, measurement techniques capable of providing dimensional form and surface finish for these features are of intense interest. This review explores the state-of-the-art inspection methodologies compatible with high-aspect-ratio structures and their suitability for extracting three-dimensional surface data based on identified high-aspect ratio structure types. Here, the abilities, limitations, challenges, and future requirements for the practical implementation and acceptance of these measurement techniques are presented.
TL;DR: In this article , a high-function stylus with water-repellent and antistatic coatings applied to the stylus tip to reduce the adhesion between the tip and measured surface due to surface forces, and conducted performance evaluation tests.
Abstract: The precise measurement of microstructures and other micron-sized materials has garnered considerable interest in recent years. We have developed a measurement system that uses an etched small diameter optical fiber as a stylus to measure microstructures with low contact force. However, when the diameter of the stylus tip is less than a few tens of micrometers, the surface forces between the measured surface and the stylus tip become larger than the gravity of the stylus tip, causing the stylus tip to stick to the measured surface. This adhesion leads to an increase in measurement time and a decrease in measurement accuracy. In this study, we fabricated a high-function stylus with water-repellent and antistatic coatings applied to the stylus tip to reduce the adhesion between the stylus tip and measured surface due to surface forces, and conducted performance evaluation tests. As a result, the average separation distance was 13.8 µm when a fluorinated resin coating with a contact angle of 105° was used, confirming that the influence of liquid bridge forces could be reduced by approximately 78%. Additionally, when static elimination experiments were conducted by scanning the charged surface at a pitch of 0.5 µm using an antistatic coating stylus with a gold on the stylus surface, the average adsorption distance was 3.6 µm, confirming that the effect of electrostatic force could be reduced by 71%.
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TL;DR: In this article, the complete tensor piezoresistance has been determined experimentally for these materials and expressed in terms of the pressure coefficient of resistivity and two simple shear coefficients.
Abstract: Uniaxial tension causes a change of resistivity in silicon and germanium of both $n$ and $p$ types. The complete tensor piezoresistance has been determined experimentally for these materials and expressed in terms of the pressure coefficient of resistivity and two simple shear coefficients. One of the shear coefficients for each of the materials is exceptionally large and cannot be explained in terms of previously known mechanisms. A possible microscopic mechanism proposed by C. Herring which could account for one large shear constant is discussed. This so called electron transfer effect arises in the structure of the energy bands of these semiconductors, and piezoresistance may therefore give important direct experimental information about this structure.
1,779 citations
"Integration of an isotropic micropr..." refers background in this paper
...The strong piezoresistive effect of silicon (about 50–100 times higher than for metals) [24, 25] allows a high integration level of extremely sensitive sensors in thin mechanical constructions....
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03 Apr 2009
TL;DR: This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of Piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.
Abstract: Piezoresistive sensors are among the earliest micromachined silicon devices. The need for smaller, less expensive, higher performance sensors helped drive early micromachining technology, a precursor to microsystems or microelectromechanical systems (MEMS). The effect of stress on doped silicon and germanium has been known since the work of Smith at Bell Laboratories in 1954. Since then, researchers have extensively reported on microscale, piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors, including many commercially successful devices. In this paper, we review the history of piezoresistance, its physics and related fabrication techniques. We also discuss electrical noise in piezoresistors, device examples and design considerations, and alternative materials. This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.
789 citations
"Integration of an isotropic micropr..." refers background in this paper
...The strong piezoresistive effect of silicon (about 50–100 times higher than for metals) [24, 25] allows a high integration level of extremely sensitive sensors in thin mechanical constructions....
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Journal Article•
498 citations
TL;DR: In this article, the authors describe requirements, different principles and characteristics of tactile probing systems in dimensional metrology, with examples of several probing systems that are used in practice, as well as a survey of tactile sensing systems.
315 citations
TL;DR: In this paper, 12 thin-film single crystal silicon specimens were tested to failure in a controlled air environment (30/spl +mn/0.1/spl deg/C, 50/spl plusmn/2% relative humidity). Damage accumulation and failure of the notched cantilever beams were monitored electrically during the fatigue life test.
Abstract: When subjected to alternating stresses, most materials degrade, e.g., suffer premature failure, due to a phenomenon known as fatigue. It is generally accepted that in brittle materials, such as ceramics, fatigue can only take place in toughened solids, i.e., premature fatigue failure would not be expected in materials such as single crystal silicon. The results of this study, however, appear to be at odds with the current understanding of brittle material fatigue. Twelve thin-film (/spl sim/20 /spl mu/m thick) single crystal silicon specimens were tested to failure in a controlled air environment (30/spl plusmn/0.1/spl deg/C, 50/spl plusmn/2% relative humidity). Damage accumulation and failure of the notched cantilever beams were monitored electrically during the "fatigue life" test. Specimen lives ranged from about 10 s to 48 days, or 1/spl times/106 to 1/spl times/1011 cycles before failure over stress amplitudes ranging from approximately 4 to 10 GPa. A variety of mechanisms are discussed in light of the fatigue life data and fracture surface evaluation.
227 citations
"Integration of an isotropic micropr..." refers background in this paper
...Due to the linearelastic and temperature-independent [20–22] mechanical behavior as well as the excellent fatigue resistance [23], silicon is the perfect material for flexible structures at the microscale....
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