Real-time 3D vibration measurements in microstructures

Kowarsch, Robert; Ochs, Wanja; Giesen, Moritz; Dräbenstedt, Alexander; Winter, Marcus; Rembe, Christian

doi:10.1117/12.922184

Cited by 7 publications

(10 citation statements)

References 6 publications

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“…5) of the measurement spot captured with an integrated camera module with defined pixel size has been evaluated to estimate the focus diameter on the specimen. The spot has a diameter of <3.5 μm, which is an improvement compared with the existing three-beam technology 5 by approximately a factor of 10. The measurement spot can be positioned on an edge, corner, etch hole of a MEMS device with a reflective surface or any light scattering feature on the object.…”

Section: Analyzing the Spot Diameter Of The Impinging Beammentioning

confidence: 74%

“…However, the formula is sufficient for most technical applications, where the (measurable) velocity of the scatter point is much lower than the velocity of light (jṽj ≪ c) and, in addition, we have measured the movement of an accurate stage to study the correctness of Eq. (1), experimentally 5 on a rough surface under presence of laser Speckle effects. Equation (1) and the schematic in Fig.…”

Section: Principle Of Laser-doppler Vibrometrymentioning

confidence: 99%

“…The combination of heterodyne interferometric detection of the measurement light with the beam path of a confocal microscope enables the out-of-plane vibration analysis of microscopic specimens. Optical crosstalk 5 of the classical three-dimensional (3-D) laser-Doppler vibrometer 6,7 is an especially critical problem for microscopic specimens as microelectromechanical-systems (MEMS). 8,9 Therefore, stroboscopic videomicroscopy [10][11][12] or stroboscopic interferometric imaging techniques [13][14][15] have been employed successfully to MEMS to study in-plane vibrations instead of applying 3-D vibrometry with three laser beams.…”

Section: Introductionmentioning

confidence: 99%

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Optical three-dimensional vibrometer microscope with picometer-resolution in x, y, and z

et al. 2014

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Abstract. The state-of-the-art technique for optical vibration analysis of macroscopic structures is laser-Doppler vibrometry in which a single-laser beam measures the motion in the beam direction. Thus, three laser beams are necessary to investigate three-dimensional (3-D) motions. The laser spots can be separated on macroscopic specimens with scattering surfaces to prevent optical crosstalk between the measurement beams, but such separation is impossible for a microscopic scatter point. We demonstrate a solution for this problem: an optical 3-D vibrometer microscope with a single-impinging laser beam, which collects scattered light from at least three directions. We prove that it is possible to realize a small laser focus of <3.5-μm diameter on a proper scatter point such as an etch hole of a microelectromechanical-systems device to obtain real-time, 3-D vibration measurements with megahertz vibration bandwidth and picometer amplitude resolution. A first measurement of operational-deflection shapes is presented. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Section: Analyzing the Spot Diameter Of The Impinging Beammentioning

confidence: 74%

Section: Principle Of Laser-doppler Vibrometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Optical three-dimensional vibrometer microscope with picometer-resolution in x, y, and z

et al. 2014

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“…Future research is directed to fast 3-D identification of resonances with a 3-D vibrometry technology [32] to employ the technology demonstrated in this paper to in-plane vibrating MEMS structures or to identify 3-D motions on the wafer level in a production environment.…”

Section: Resultsmentioning

confidence: 98%

Determination of Parameters With Uncertainties for Quality Control in MEMS Fabrication

Gennat

Meinig

Shaporin

et al. 2013

J. Microelectromech. Syst.

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A reliable technique for rapid monitoring of critical dimensional and material parameters during the fabrication of microelectromechanical systems (MEMS) is still an open task. Electrical excitation is sometimes simply not possible, or an electrical test does not reveal sufficient information for a complete characterization. In this paper, we present a new approach that employs optical testing of MEMS vibration frequencies. It is not necessary to have electrical connections because we have developed probes with transparent electrodes to excite vibrations electrostatically without contact on the wafer level. Broadbandwidth excitation is applied to detect all relevant resonances interferometrically through the probes in a single broad-band measurement. Peak detection of the resonances results in a measurement vector containing the resonant frequencies. We demonstrate a new method to estimate system parameters by model identification. The analytical models are derived from a general approach based on finite-element analysis. The parameters with uncertainties are finally determined by guaranteed parameter estimation.[2012-0315]

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“…proportional zum Sinus des halben Detektionswinkels θ/2, skaliert mit dem Faktor κ aus(6). Würde man nur den SNR betrachten, wäre demnach ein Detektionswinkel von θ ≈ 55 • optimal.…”

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Schwingungen in Mikrostrukturen 3D-Laservibrometer-Mikroskop mit nur einem Messstrahl

Winter¹,

Steger²,

Giesen³

et al. 2013

Tm - Technisches Messen

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Zusammenfassung Wir stellen ein neues Messmikroskop vor, welches die Erfassung von dreidimensionalen Schwingungsparametern mikroskopischer Objekte in Echtzeit ermöglicht. Das Messsystem besteht aus einem einzigen, integrierten Messkopf, der den von einem mikroskopischen Messobjekt in drei Raumrichtungen gestreuten Laserstrahl analysiert und daraus die dreidimensionale Objektbewegung bestimmt. Die Messpunktgröße ist hierbei kleiner als 4 μm, wobei optisches Übersprechen zwischen den drei Analyserichtungen vermieden wird, da es nur einen Messlaserstrahl gibt.Summary We present a new type of measurement microscope which is able to detect three-dimensional vibration parameters of microscopic objects in real-time.The measurement system comprises a single, integrated measurement head which analyzes the light scattered by the object into three directions to determine the threedimensional object motion. The measurement spot size is less than 4 μm. Optical crosstalk between the analysis directions is avoided by using only a single laser beam for measurement.

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Real-time 3D vibration measurements in microstructures

Cited by 7 publications

References 6 publications

Optical three-dimensional vibrometer microscope with picometer-resolution in x, y, and z

Optical three-dimensional vibrometer microscope with picometer-resolution in x, y, and z

Determination of Parameters With Uncertainties for Quality Control in MEMS Fabrication

Schwingungen in Mikrostrukturen 3D-Laservibrometer-Mikroskop mit nur einem Messstrahl

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