Next Article in Journal
Coevolution of the Features of the Dynamics of the Accelerator Pedal and Hyperparameters of the Classifier for Emergency Braking Detection
Next Article in Special Issue
Learning Micromanipulation, Part 1: An Approach Based on Multidimensional Ability Inventories and Text Mining
Previous Article in Journal
A Bouc–Wen Model-Based Compensation of the Frequency-Dependent Hysteresis of a Piezoelectric Actuator Exhibiting Odd Harmonic Oscillation
Previous Article in Special Issue
Polymer Microgripper with Autofocusing and Visual Tracking Operations to Grip Particle Moving in Liquid
Open AccessArticle

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

1
Department of Mechanical Engineering, Faculty of Engineering, University of Malta, MSD 2080 Msida, Malta
2
Department of Microelectronics and Nanoelectronics, Faculty of Information and Communication Technology, University of Malta, MSD 2080 Msida, Malta
3
Department of Metallurgy and Materials Engineering, Faculty of Engineering, University of Malta, MSD 2080 Msida, Malta
*
Author to whom correspondence should be addressed.
Actuators 2018, 7(3), 38; https://doi.org/10.3390/act7030038
Received: 20 June 2018 / Revised: 9 July 2018 / Accepted: 11 July 2018 / Published: 15 July 2018
(This article belongs to the Special Issue Micromanipulation)
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®) that are produced by MEMSCAP, Inc. (Durham, NC, USA) and that include both surface micromachined (PolyMUMPs™) and silicon-on-insulator (SOIMUMPs™) 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™ 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™ 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® (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™ 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. View Full-Text
Keywords: MEMS microgrippers; micromanipulation; red blood cells; electrothermal actuation; PolyMUMPs™; SOIMUMPs™; structure thickness; air gap thickness; polysilicon; single crystal silicon MEMS microgrippers; micromanipulation; red blood cells; electrothermal actuation; PolyMUMPs™; SOIMUMPs™; structure thickness; air gap thickness; polysilicon; single crystal silicon
Show Figures

Figure 1

MDPI and ACS Style

Cauchi, M.; Grech, I.; Mallia, B.; Mollicone, P.; Sammut, N. The Effects of Structure Thickness, Air Gap Thickness and Silicon Type on the Performance of a Horizontal Electrothermal MEMS Microgripper. Actuators 2018, 7, 38.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop