Surface micromachining

About: Surface micromachining is a research topic. Over the lifetime, 11465 publications have been published within this topic receiving 241467 citations.

High quality factors of silicon membranes with piezoelectric actuation and detection scheme for biosensing purpose in liquid media

Abstract: The paper is about 4 times 4 matrices of piezoelectric membranes that were fabricated by standard micromachining techniques starting with silicon-on-insulator (SOI) wafer. Each membrane (circular shaped) can be individually addressed for actuation and sensing applications through a PbZr(x)Ti(1-x)O3 (PZT) 800-nm thick film. The main objective of this work is to study the dynamic behavior of the piezoelectric membranes in air and liquid media. The results showed high quality factors in air (up to 150) and in water-glycerol (lowered by a factor 4 for a glycerol proportion in water less than 30%) while the resonant frequencies were significantly decreased by the liquid apparent added mass effects

High aspect ratio Si etching technique and application

Abstract: Bulk silicon micromachining is becoming a hot topic in MEMS technology. This is mainly attributed to the breakthrough of high aspect ratio silicon etching. This article provides a new method of high aspect ratio silicon etching using fluorine based chemistries, SF/sub 6/ and C/sub 4/F/sub 8/, in an ICP system with a function of processing gases switching. The experiments demonstrate that the process results can meet most demands in bulk silicon micromachining processes. Two examples of a dry etching release process and fabrication of micro-silicon model are given to show the application of this technique.

A Simple Optical Gas Sensor Based on Micromachined Silicon Plasma Igniters and Image Processing

Abstract: The early developments of an optical gas sensor combining plasma ignition by silicon electrode arrays and optical detection coupled with image processing are presented in this paper. The principle of the sensor under development is based on the ionization of chemical species under intense electrical fields and the detection by optical sensors of photons created by glow discharges. Electrodes optimization by electrostatic simulations has led to the design and fabrication of micromachined silicon igniters bonded to a glass substrate. First characterizations of the plasma igniters will be also presented.

Crystallographic effects during micromachining - A finite-element model

Abstract: Mechanical micromachining is a powerful and effective way for manufacturing small sized machine parts. Even though the micromachining process is similar to the traditional machining, the material behavior during the process is much different. In particular, many researchers report that the basic mechanics of the work material is affected by microstructures and their crystallographic orientations. For example, crystallographic orientations of the work material have significant influence on force response, chip formation and surface finish. In order to thoroughly understand the effect of crystallographic orientations on the micromachining process, finite-element model (FEM) simulating orthogonal cutting process of single crystallographic material was presented. For modeling the work material, rate sensitive single crystal plasticity of face-centered cubic (FCC) crystal was implemented. For the chip formation during the simulation, element deletion technique was used. The simulation model is developed using ABAQUS/explicit with user material subroutine via user material subroutine (VUMAT). Simulations showed that variation of the specific cutting energy at different crystallographic orientations of work material shows significant anisotropy. The developed FEM model can be a useful prediction tool of micromachining of crystalline materials.

Fabrication and metrology of electromagnetically actuated microcantilever arrays for biochemical sensing

Abstract: Since their first applications in atomic force microscopy (AFM) micro- and nanocantilevers have been using as a very versatile tool for nanotechnology for over two decades. Their applications cover fields of micro-and nanomanipulation, micro- and nanocalorimetry, force and mass sensing. Variety of methods and techniques for actuation and detection of cantilevers' motion have been proposed and widely used, each exhibiting its advantages and drawbacks. In this paper we present architecture of the microcantilever whose deflection is actuated electromagnetically by the Lorentz force. Optical beam deflection (OBD) method was used to observe the beam static and resonance displacement. We also present characteristics of the proposed system and describe numerous applications in modern biochemical diagnostics. These include biosensing, mass change detection, nanometer range manipulation and force measurements with the resolution of several piconewtons. In the presented experiments an array of rectangular silicon cantilevers fabricated using double side micromachining was used. A layer of gold was deposited on the top side of the microcantilevers creating a current line for actuation, a reflective pad at the apex, and a substrate for thiol-based self-assembled monolayers (SAMs).