Development of reactive ion etching process for deep etching of silicon for micro-mixer device fabrication
01 Apr 2014-pp 1-6
TL;DR: In this paper, the authors report the design, fabrication, packaging and testing of a micro-mixer microfluidic device in 2" diameter silicon substrate, which was formed employing modified reactive ion etching (RIE) process.
Abstract: In the present work, we report the design, fabrication, packaging and testing of a micro-mixer microfluidic device in 2" diameter silicon substrate. For this purpose, long and deep (∼ 80 μm) channels in silicon were formed employing modified reactive ion etching (RIE) process. The RIE process parameters were carefully optimised for obtaining fast etch rate for creating 80 μm deep channels. Silicon wafers were anodically bonded to a Corning® 7740 glass plate of identical sizes, for the purpose of fluid confinement. Through holes were made either in silicon substrate or in glass plate for formation of input/output ports. The channels were characterized using stylus and optical profilometers. The micromixer device was packaged in a polycarbonate housing and pressure drop versus flow rate measurements were carried out. The Reynolds Number and Friction Factor were calculated and it was concluded that the flow of gas was laminar at flow rates of oxygen ranging from 0.4 to 25 seem.
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TL;DR: In this paper, a simple and efficient method for synthesis of ZnO nanowires by thermal oxidation of sputter deposited Zn film and their integration with MEMS technologies to fabricate a sensor for acetone vapour detection was reported.
Abstract: In this work, we report a simple and efficient method for synthesis of ZnO nanowires by thermal oxidation of Zn film and their integration with MEMS technologies to fabricate a sensor for acetone vapour detection. ZnO nanowires were prepared by thermal oxidation of sputter deposited Zn film. The nanostructured ZnO was characterized by x-ray diffraction, a scanning electron microscope and room temperature photoluminescence measurements. The ZnO nanowires synthesis process was integrated with MEMS technologies to obtain a sensor for volatile organic compounds, incorporating an on-chip Ni microheater and an interdigited electrode structure. To reduce the heat loss from the on-chip microheater, the sensor was made on a thin silicon diaphragm obtained via a modified reactive ion etching process. This resulted in considerable power saving during sensor operation. For this, a three-mask process was used. The performance of the microheater was simulated on COMSOL and validated experimentally. The sensor has been tested for acetone vapour sensing and the operating parameters were optimized. The sensor has the ability to detect acetone vapour at 5 parts per million (ppm) concentrations when operated at 100 °C. The sensor consumed only 36 mW power and showed a high-sensitivity value of 26.3% for 100 ppm of acetone vapour.
19 citations
Dissertation•
23 Aug 2017
5 citations
Cites background from "Development of reactive ion etching..."
...The major factors which effect the etch profile of the substrate are the gas flow, the pressure at which the chamber is maintained, the RF frequency and RF power [91][92]....
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01 Mar 2021-Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems
TL;DR: In this paper, a self-encapsulated and recessed micro-cantilever beam is used to secure the recessed cantilever from one side of a DC MEMS switch.
Abstract: In the present work, we report design, fabrication and testing of a novel DC MEMS switch incorporating a self-encapsulated and recessed micro-cantilever beam. Wafer level anodic bonding with press-on contacts between silicon and glass is used innovatively to secure the recessed cantilever beam from one side. The cantilever is made of single crystal silicon in a recessed cavity whereas actuating electrode and signal lines are formed on corning glass. Anodic bonding provides “press on contacts” between silicon and glass plate and also secures the cantilever beam in the recessed cavity in silicon. The signal lines and pull-in electrode are formed on the glass plate using aluminium metallization while the cantilever has a gold pad at its tip. The anodic bonding provides three major advantages (i) it encapsulates the fragile beam and thus protects it from damage during dicing and packaging process (ii) it provides press-on contact between signal lines on glass plate and bonding pads on silicon (iii) it makes the beam optically visible. The devices were simulated using COMSOL multiphysics software and the results were compared with experimentally measured values. The cantilever based switch operates at low actuation voltage (average ~ 12 V) indicating that it can be used for power electronic circuits and various other applications.
1 citations
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TL;DR: Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes to devices that handle aqueous solutions.
Abstract: Microfluidic devices are finding increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry, and systems for fundamental research. Conventional methods of fabricating microfluidic devices have centered on etching in glass and silicon. Fabrication of microfluidic devices in poly(dimethylsiloxane) (PDMS) by soft lithography provides faster, less expensive routes than these conventional methods to devices that handle aqueous solutions. These soft-lithographic methods are based on rapid prototyping and replica molding and are more accessible to chemists and biologists working under benchtop conditions than are the microelectronics-derived methods because, in soft lithography, devices do not need to be fabricated in a cleanroom. This paper describes devices fabricated in PDMS for separations, patterning of biological and nonbiological material, and components for integrated systems.
3,344 citations
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TL;DR: In this paper, the authors report the progress on the recent development of micromixers and present different types and designs of active and passive MCMs, as well as the operation points of the MCMs.
Abstract: This review reports the progress on the recent development of micromixers. The review first presents the different micromixer types and designs. Micromixers in this review are categorized as passive micromixers and active micromixers. Due to the simple fabrication technology and the easy implementation in a complex microfluidic system, passive micromixers will be the focus of this review. Next, the review discusses the operation points of the micromixers based on characteristic dimensionless numbers such as Reynolds number Re, Peclet number Pe, and in dynamic cases the Strouhal number St. The fabrication technologies for different mixer types are also analysed. Quantification techniques for evaluation of the performance of micromixers are discussed. Finally, the review addresses typical applications of micromixers.
1,651 citations
"Development of reactive ion etching..." refers background in this paper
...[5] Numerous applications of these lab-onchip devices are mentioned in the literature [5-7]....
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TL;DR: An overview of research activities in the field of fluid components or systems built with microfabrication technologies is given in this paper, focusing on the fluidic behaviour of the various devices, such as valves, pumps and flow sensors as well as the possibilities and pitfalls related to the modelling of these devices using simple flow theory.
Abstract: An overview is given of research activities in the field of fluid components or systems built with microfabrication technologies. This review focuses on the fluidic behaviour of the various devices, such as valves, pumps and flow sensors as well as the possibilities and pitfalls related to the modelling of these devices using simple flow theory. Finally, a number of microfluidic systems are described and comments on future trends are given.
1,153 citations
TL;DR: A high level overview of the field of microfluidic mixing devices is provided before describing some of the more significant proposals for active and passive mixers.
Abstract: The aim of microfluidic mixing is to achieve a thorough and rapid mixing of multiple samples in microscale devices. In such devices, sample mixing is essentially achieved by enhancing the diffusion effect between the different species flows. Broadly speaking, microfluidic mixing schemes can be categorized as either “active”, where an external energy force is applied to perturb the sample species, or “passive”, where the contact area and contact time of the species samples are increased through specially-designed microchannel configurations. Many mixers have been proposed to facilitate this task over the past 10 years. Accordingly, this paper commences by providing a high level overview of the field of microfluidic mixing devices before describing some of the more significant proposals for active and passive mixers.
910 citations
"Development of reactive ion etching..." refers background in this paper
...If Re < 2000, the flow is generally considered laminar, 2000 < Re < 4000 is the transition and if Re > 4000, flow is turbulent [2,3,15]....
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TL;DR: Fundamentals of PDMS-based microfluidic devices and their functions are described as well as the experimental results, where microreactors, microchips for capillary gel electrophoresis, and hydrophobic vent valves are successfully fabricated and operated.
479 citations