Microelectromechanical systems

About: Microelectromechanical systems is a research topic. Over the lifetime, 10255 publications have been published within this topic receiving 151342 citations. The topic is also known as: MEMS & microelectromechanical system.

Soft lithography for micro- and nanoscale patterning

Abstract: This protocol provides an introduction to soft lithography--a collection of techniques based on printing, molding and embossing with an elastomeric stamp. Soft lithography provides access to three-dimensional and curved structures, tolerates a wide variety of materials, generates well-defined and controllable surface chemistries, and is generally compatible with biological applications. It is also low in cost, experimentally convenient and has emerged as a technology useful for a number of applications that include cell biology, microfluidics, lab-on-a-chip, microelectromechanical systems and flexible electronics/photonics. As examples, here we focus on three of the commonly used soft lithographic techniques: (i) microcontact printing of alkanethiols and proteins on gold-coated and glass substrates; (ii) replica molding for fabrication of microfluidic devices in poly(dimethyl siloxane), and of nanostructures in polyurethane or epoxy; and (iii) solvent-assisted micromolding of nanostructures in poly(methyl methacrylate).

Fundamentals of microfabrication : the science of miniaturization

Abstract: LITHOGRAPHY Introduction Historical Note: Lithography's Origins Photolithography Overview Critical Dimension, Overall Resolution, Line-Width Lithographic Sensitivity and Intrinsic Resist Sensitivity (Photochemical Quantum Efficiency) Resist Profiles Contrast and Experimental Determination of Lithographic Sensitivity Resolution in Photolithography Photolithography Resolution Enhancement Technology Beyond Moore's Law Next Generation Lithographies Emerging Lithography Technologies PATTERN TRANSFER WITH DRY ETCHING TECHNIQUES Introduction Dry Etching: Definitions and Jargon Plasmas or Discharges Physical Etching: Ion Etching or Sputtering and Ion-Beam Milling Plasma Etching (Radical Etching) Physical/Chemical Etching PATTERN TRANSFER WITH ADDITIVE TECHNIQUES Introduction Silicon Growth Doping of Si Oxidation of Silicon Physical Vapor Deposition Chemical Vapor Deposition Silk-Screening or Screen-Printing Sol-Gel Deposition Technique Doctors' Blade or Tape Casting Plasma Spraying Deposition and Arraying Methods of Organic Layers in BIOMEMS Thin versus Thick Film Deposition Selection Criteria for Deposition Method WET BULK MICROMACHINING Introduction Historical Note Silicon Crystallography Silicon As Substrate Silicon As A Mechanical Element In MEMS Wet Isotropic And Anisotropic Etching Alignment Patterns Chemical Etching Models Etching With Bias And/Or Illumination Of The Semiconductor Etch-Stop Techniques Problems With Wet Bulk Micromachining SURFACE MICROMACHINING Introduction Historical Note Mechanical Properties of Thin Films Surface Micromachining Processes Poly-Si Surface Micromachining Modifications Non-Poly-Si Surface Micromachining Modifications Materials Case Studies LIGA AND MICROMOLDING Introduction LIGA-Background LIGA and LIGA-Like Process Steps A COMPARISON OF MINIATURIZATION TECHNIQUES: TOP-DOWN AND BOTTOM-UP MANUFACTURING Introduction Absolute and Relative Tolerance in Manufacturing Historical Note: Human Manufacturing Section I: Top-Down Manufacturing Methods Section II: Bottom-Up Approaches MODELING, BRAINS, PACKAGING, SAMPLE PREPARATION AND NEW MEMS MATERIALS Introduction Modeling Brains In Miniaturization Packaging Substrate Choice SCALING, ACTUATORS, AND POWER IN MINIATURIZED SYSTEMS Introduction Scaling Actuators Fluidics Scaling In Analytical Separation Equipment Other Actuators Integrated Power MINIATURIZATION APPLICATIONS Introduction Definitions and Classification Method Decision Three OVERALL MARKET For MICROMACHINES Introduction Why Use Miniaturization Technology ? From Perception to Realization Overall MEMS Market Size MEMS Market Character MEMS Based on Si Non-Silicon MEMS MEMS versus Traditional Precision Engineering The Times are a'Changing APPENDICES Metrology Techniques WWW Linkpage Etch Rate for Si, SiO2 Summary of Top-Down Miniaturization Tools Listing of names of 20 amino acids & their chemical formulas Genetic code Summary of Materials and Their Properties for Microfabrication References for Detailed Market Information on Miniature Devices MEMS Companies Update Suggested Further Reading Glossary Symbols used in Text INDEX Each chapter also contains sections of examples and problems

Metal-Assisted Chemical Etching of Silicon: A Review

Abstract: This article presents an overview of the essential aspects in the fabrication of silicon and some silicon/germanium nanostructures by metal-assisted chemical etching. First, the basic process and mechanism of metal-assisted chemical etching is introduced. Then, the various influences of the noble metal, the etchant, temperature, illumination, and intrinsic properties of the silicon substrate (e.g., orientation, doping type, doping level) are presented. The anisotropic and the isotropic etching behaviors of silicon under various conditions are presented. Template-based metal-assisted chemical etching methods are introduced, including templates based on nanosphere lithography, anodic aluminum oxide masks, interference lithography, and block-copolymer masks. The metal-assisted chemical etching of other semiconductors is also introduced. A brief introduction to the application of Si nanostructures obtained by metal-assisted chemical etching is given, demonstrating the promising potential applications of metal-assisted chemical etching. Finally, some open questions in the understanding of metal-assisted chemical etching are compiled.

Micro-electro-mechanical-systems (mems) and fluid flows

Abstract: The micromachining technology that emerged in the late 1980s can provide micron-sized sensors and actuators. These micro transducers are able to be integrated with signal conditioning and processing circuitry to form micro-electromechanical-systems (MEMS) that can perform real-time distributed control. This capability opens up a new territory for flow control research. On the other hand, surface effects dominate the fluid flowing through these miniature mechanical devices because of the large surface-to-volume ratio in micron-scale configurations. We need to reexamine the surface forces in the momentum equation. Owing to their smallness, gas flows experience large Knudsen numbers, and therefore boundary conditions need to be modified. Besides being an enabling technology, MEMS also provide many challenges for fundamental flow-science research.

The Fluid Mechanics of Microdevices—The Freeman Scholar Lecture

Abstract: Manufacturing processes that can create extremely small machines have been developed in recent years. Microelectromechanical systems (MEMS) refer to devices that have characteristic length of less than 1 mm but more than 1 micron, that combine electrical and mechanical components and that are fabricated using integrated circuit batch-processing techniques. Electrostatic, magnetic, pneumatic and thermal actuators, motors, valves, gears, and tweezers of less than 100-μm size have been fabricated. These have been used as sensors for pressure, temperature, mass flow, velocity and sound, as actuators for linear and angular motion and as simple components for complex systems such as micro-heat-engines and micro-heat-pumps The technology is progressing at a rate that fa r exceeds that of our understanding of the unconventional physics involved in the operation as well as the manufacturing of those minute devices. The primary objective of this article is to critically review the status of our understanding of fluid flow phenomena particular to microdevices. In terms of applications, the paper emphasizes the use of MEMS as sensors and actuators for flow diagnosis and control.