Compliance Synthesis of CSFH MEMS-Based Microgrippers

Verotti, Matteo; Dochshanov, Alden; Belfiore, Nicola Pio

doi:10.1115/1.4035053

Cited by 46 publications

(30 citation statements)

References 51 publications

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“…More recently, new emerging MEMS-Technology based instruments for biomedical and surgical applications have been developed. In fact, based on a new concept hinge [28,29], a class of different microgrippers, equipped with rotary comb-drives, has been developed [30][31][32][33], also in significant environments [34], and fabricated [35,36]. Thanks to their size, these instruments are expected to be employed in surgery and diagnostics.…”

Section: Introductionmentioning

confidence: 99%

Toward Operations in a Surgical Scenario: Characterization of a Microgripper via Light Microscopy Approach

et al. 2019

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Micro Electro Mechanical Systems (MEMS)-Technology based micro mechanisms usually operate within a protected or encapsulated space and, before that, they are fabricated and analyzed within one Scanning Electron Microscope (SEM) vacuum specimen chamber. However, a surgical scenario is much more aggressive and requires several higher abilities in the microsystem, such as the capability of operating within a liquid or wet environment, accuracy, reliability and sophisticated packaging. Unfortunately, testing and characterizing MEMS experimentally without fundamental support of a SEM is rather challenging. This paper shows that in spite of large difficulties due to well-known physical limits, the optical microscope is still able to play an important role in MEMS characterization at room conditions. This outcome is supported by the statistical analysis of two series of measurements, obtained by a light trinocular microscope and a profilometer, respectively.

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Section: Introductionmentioning

confidence: 99%

Toward Operations in a Surgical Scenario: Characterization of a Microgripper via Light Microscopy Approach

et al. 2019

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“…The constantly growing need for high-precision micromanipulation has seen the implementation of microelectromechanical systems (MEMS) in numerous applications within the micromanufacturing and biomedical fields. Microgrippers are one such type of MEMS devices that are typically designed to safely manipulate biological cells [1][2][3][4][5][6][7][8][9] as well as micromechanical parts [10][11][12]. The successful development of a MEMS microgripper depends on taking into account several factors including the design and mechanical structure [13], the actuation mechanism [14,15], the choice of materials used [16][17][18][19], the operational requirements and limitations [20], the fabrication technology [21][22][23][24][25][26], and the environment in which the microgripper will be operated [27].…”

Section: Introductionmentioning

confidence: 99%

The Effects of Structure Thickness, Air Gap Thickness and Silicon Type on the Performance of a Horizontal Electrothermal MEMS Microgripper

et al. 2018

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The ongoing development of microelectromechanical systems (MEMS) over the past decades has made possible the achievement of high-precision micromanipulation within the micromanufacturing, microassembly and biomedical fields. This paper presents different design variants of a horizontal electrothermally actuated MEMS microgripper that are developed as microsystems to micromanipulate and study the deformability properties of human red blood cells (RBCs). The presented microgripper design variants are all based on the U-shape 'hot and cold arm' actuator configuration, and are fabricated using the commercially available Multi-User MEMS Processes (MUMPs R ) that are produced by MEMSCAP, Inc. (Durham, NC, USA) and that include both surface micromachined (PolyMUMPs TM ) and silicon-on-insulator (SOIMUMPs TM ) MEMS fabrication technologies. The studied microgripper design variants have the same in-plane geometry, with their main differences arising from the thickness of the fabricated structures, the consequent air gap separation between the structure and the substrate surface, as well as the intrinsic nature of the silicon material used. These factors are all inherent characteristics of the specific fabrication technologies used. PolyMUMPs TM utilises polycrystalline silicon structures that are composed of two free-standing, independently stackable structural layers, enabling the user to achieve structure thicknesses of 1.5 µm, 2 µm and 3.5 µm, respectively, whereas SOIMUMPs TM utilises a 25 µm thick single crystal silicon structure having only one free-standing structural layer. The microgripper design variants are presented and compared in this work to investigate the effect of their differences on the temperature distribution and the achieved end-effector displacement. These design variants were analytically studied, as well as numerically modelled using finite element analysis where coupled electrothermomechanical simulations were carried out in CoventorWare R (Version 10, Coventor, Inc., Cary, NC, USA). Experimental results for the microgrippers' actuation under atmospheric pressure were obtained via optical microscopy studies for the PolyMUMPs TM structures, and they were found to be conforming with the predictions of the analytical and numerical models. The focus of this work is to identify which one of the studied design variants best optimises the microgripper's electrothermomechanical performance in terms of a sufficient lateral tip displacement, minimum out-of-plane displacement at the arm tips and good heat transfer to limit the temperature at the cell gripping zone, as required for the deformability study of RBCs.

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“…Since 2013 [16,17], a new class of MEMS, equipped with Conjugate Surface Flexure Hinges (CSFH) has been developed [18,19] and fabricated [20]. A sample of CSFH is depicted in Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Scalloping and Stress Concentration in DRIE-Manufactured Comb-Drives

et al. 2018

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In the last decades, microelectromechanical systems have been increasing their number of degrees of freedom and their structural complexity. Hence, most recently designed MEMSs have required higher mobility than in the past and higher structural strength and stability. In some applications, device thickness increased up to the order of tens (or hundred) of microns, which nowadays can be easily obtained by means of DRIE Bosch process. Unfortunately, scalloping introduces stress concentration regions in some parts of the structure. Stress concentration is a dangerous source of strength loss for the whole structure and for comb-drives actuators which may suffer from side pull-in. This paper presents an analytical approach to characterize stress concentrations in DRIE micro-machined MEMS. The method is based on the linear elasticity equations, the de Saint-Venant Principle, and the boundary value problem for the case of a torsional state of the beam. The results obtained by means of this theoretical method are then compared with those obtained by using two other methods: one based on finite difference discretization of the equations, and one based on finite element analysis (FEA). Finally, the new theoretical approach yields results which are in accordance with the known value of the stress concentration factor for asymptotically null radius notches.

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Compliance Synthesis of CSFH MEMS-Based Microgrippers

Cited by 46 publications

References 51 publications

Toward Operations in a Surgical Scenario: Characterization of a Microgripper via Light Microscopy Approach

Toward Operations in a Surgical Scenario: Characterization of a Microgripper via Light Microscopy Approach

The Effects of Structure Thickness, Air Gap Thickness and Silicon Type on the Performance of a Horizontal Electrothermal MEMS Microgripper

Scalloping and Stress Concentration in DRIE-Manufactured Comb-Drives

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