Microsystem

This paper presents an analysis and experiment of centrifugal force for microfluidic Enzyme-Linked Immunosorbent Assay (ELISA) on a compact-disc (CD) platform. The ELISA CD was designed based on the centrifugal force as a driving force while capillary force acts as preventing barrier. The CD composed of 2 layers: the substrate layer is made of PMMA and the top layer is laminated with an Adhesive Sealing Films (ASF) or thermal seal. The PMMA substrate was fabricated by CNC micromachining. The ELISA CD consists of 7 reservoirs: waste, detection, serum, conjugate, washing solution, substrate and stopping solution. In the experiment, the reservoirs were filled with colour liquid and the fluid flow behaviour of the liquid in the CD was studied and monitored by a customized CD spin stand system equipped with visualization system. The experimental test results show an average of 9% error when compared with the theoretical calculation of burst frequency for all the reservoirs. © 2010 IEEE.

ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=5742282

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We present a thermally activated solvent bonding technique for the formation of embedded microstructures in polymer. It is based on the temperature dependent solubility of polymer in a liquid that is not a solvent at room temperature. With thermal activation, the liquid is transformed into a solvent of the polymer, creating a bonding capability through segmental or chain interdiffusion at the bonding interface. The technique has advantages over the more commonly used thermal bonding due to its much lower operation temperature (30°C lower than the material’s T g), lower load, as well as shorter time. Lap shear test indicated bonding shear strength of up to 2.9 MPa. Leak test based on the bubble emission technique showed that the bonded microfluidic device can withstand at least six bars (87 psi) of internal pressure (gauge) in the microchannel. This technique can be applied to other systems of polymer and solvent.

New designs for a 1 times 4 and a 1 times 8 CWDM multiplexers based on cascaded groups of series coupled ring resonators are presented. Compared to other integrated optical alternatives such as MMI phasars, cascaded Mach-Zehnder interferometers and cascaded AWG, the proposed circuits offer superior performance in their very sharp roll-off factor that exceeds 0.75, their reduced crosstalk level that lies below -80 dB and their negligible insertion loss for the 1 times 4 design. For the 1 times 8 design, the worst case insertion loss is 4 dB. However, the performances obtained exhibit passband ripples in the order of 5 dB, and besides, they are not very tolerant to fabrication errors. Being designed for SOI technology, the proposed circuits are compact as the circuit areas are 130 times 130 mum2 and 90 times 150 mum2 for the 1 times 4 and 1 times 8 designs, respectively. They also have a high potential for MEMS tunability.

A three-dimensional (3D) Low Temperature Cofired Ceramics (LTCC) fluidic microsystem integrated with an optical detection unit is presented in this article. The structure is applied to quantitative analysis of chemical compounds using colorimetric methods. The fabricated microfluidic system consists of a serpentine mixer, fluidic channels, heater, embedded temperature sensor and integrated optical fibers for detection of light transmission and/or fluorescence. A new inexpensive material for the embedded temperature sensor is described. The fluidic system is designed using computer CFD (Computational Fluid Dynamics) simulations. Fluid flow in the mixer is observed through a transparent polymer material bonded to the LTCC structure. The importance of positioning of optical fibers and their influence on the absorbance and fluorescence measurements is presented.

Current research work on the development of automated microrobot-based nanohandling stations (AMNSs) using the probe of an atomic force microscope (AFM) as an endeffector is presented. The manipulation of individual multiwalled carbon nanotubes (MWCNTs) and the characterization of biological objects, as for instance cells or ligand-receptor bindings are aspired applications. For this reason, the developed AMNSs have to be integrated both into a scanning electron microscope (SEM) for the nanomanipulation of carbon nanotubes (CNTs) and into an optical microscope for the cell characterization. Such an AMNS combines different micro- and nanomanipulators, each offering three degrees of freedom, in order to perform the coarse and fine positioning between object and endeffector. Piezo-resistive AFM probes are applied as endeffectors allowing to measure the acting forces and to realize force feedback for the station’s control system. First, investigations have been carried out by bending MWCNTs and calculating their Young’s modulus. Electrically conductive adhesives (ECAs) have been developed for the microelectronics industry, and their mechanical properties have to be determined. Therefore an AMNS for the mechanical characterization of thin ECA coatings by nanoindentation inside an SEM is presented as well, showing first experimental results. The three application areas shown in this paper will provide the basis for using the considered materials in MEMS/NEMS- and biosensor-devices.

Abstract Aluminum-coated silicon substrates are commonly used for various micro/nanooptoelectromechanical systems (MOEMS/NOEMS) including Digital Micromirror Devices (DMD®). For efficient and failure proof operation of these devices, ultra-thin ...

This paper presents a SOI Hall sensor based microsystem for energy measurement. The mixed-mode signal circuitry has been entirely designed and integrated in the experimental 0.5@mm fully depleted SOI 3V technology. It consists of an integrated Hall element, chopper stabilized sensor bias system, analog front end and digital back end. Aiming at performing accurate measurements, we have implemented a high linearity analog front end, as well as a high-resolution analog-to-digital conversion technique. Two versions of the microsystem have been realized. The first test chip contains a classical instrumentation amplifier as sensor amplifier, whereas the second one contains a linearized differential-difference amplifier as sensor amplifier. Both microsystems are fully functional and permits one to perform the measurements with an overall system error that is less than +/-1.5%.

This paper explores a comparative study between different designs of electrothermal microactuators with emphasis on optimal design and performance key factors. For this purpose, two typical designs for electrothermal microactuators with the same material properties are studied: one with different beam lengths (design A), other one with different beam sections and a flexure part (design B). Analytical model and finite element model (FEM) have been developed and validated by comparison of simulation results with experimental results in literature. Optimal geometrical dimensions to achieve maximum deflection have been obtained using genetic algorithm (GA). As the key factors, temperature distribution, power consumption and deflection of these microactuators have been compared in the range of microactuator functionality. Design B is more sensitive to geometrical dimension variation. Using optimal geometrical dimensions, an increase of almost 40 and 55% has been achieved for design A and...

Abstract As the micro technology field expands, the need of simple and standardized procedures to precisely evaluate device functionality, realibility and quality of micro electro mechanical systems devices increases. In this paper the application of two empirical methods suitable for the ...