Microsystem fabrication

Obeid and coworkers [128] reported a microsystem fabricated on two glass plates (each 40 x 45 x 0.55 mm), where a continuous channel network was etched into the bottom plate by standard photolithography and wet chemical etching, followed by thermal fusion-bonding of the two plates to form a closed stmcture. This system (see Fig. 14a) used a continuous flow concept to demonstrate functional integration of reverse transcription (RT) and PCR (RT-PCR) with operator selection of the number of amplification cycles to secure the results shown in Fig. 14b. The RT phase of the measurement involved the synthesis of DNA using mRNA templates and was performed before DNA amplification to allow quantification of mRNAs. The integration of RT and PCR processes within a monolithic chip is often problematic as RT components can interfere with the subsequent PCR... 

FIGURE 47.4 Photograph of a microsystem fabricated via the multilayered structure route (top) and on-chip HPLC separation of cytochrome c digest using a lauryl methacrylate-based monolithic colnmn (bottom). (Reprinted with permission from Le Gac, S., et al., J. Chromatogr. B, 808, 3, 2(K)4. Copyright 2004 Elsevier B.V.) Conditions sample concentration 800 fmol, mobile phase A, 5% acetonitrile in 0.1% aqueons formic acid, mobile phase B, 95% acetonitrile in 0.1 % aqueous formic acid, gradient 5-50% B in A in 30 min, 50-95% B in A in 1 min, flow-rate 200 nL/min. 

Dietrich, T. R., Ehrfeld, W., Lacher, M., Kramer, M., Speit, B., Fabrication technologies for microsystems utilizing photoetchable glass, Micoelectron. Eng. 

The answer lies in microsystem design and fabrication, applied to a relatively simple arrangement of gas sensors (the higher the integration the better). Combined with microelectronics, it is perfectly suited for the mass production of EN modules. Microsystems are usually produced in batches and will meet demand at low cost. Additionally, small size, low energy consumption and long-term stability can be achieved. Of course, not only consumer applications will benefit from the microsystem approach, since the improvements are also relevant to instruments used in industrial applications, medical care or in environmental monitoring. 

A small serial production has been set up at the Institute for Instrumental Analysis to develop and demonstrate the fabrication of the microsystem. The production can be subdivided into four phases The wafer-based formation of the fundamental structure, the packaging stage including separation, housing assembly and contact formation of the chips, the deposition of the gradient membrane and the final annealing treatment [4, 5]. 

F. Solzbacher, Microsystems technol- 2 F. Solzbacher, Fabrication Technolo-... 

The fabrication of the sensor system was described in Sect. 4.1.2, since this microsystem also features a circular microhotplate. A micrograph of the complete microsystem (die size 6.8 x 4.7 mm ) is shown in Fig. 5.2. The microhotplate is located in the upper section of the chip. The analog circuitry and the A/D and D/A converters are clearly separated and shielded from the digital circuitry. The bulk-chip temperature sensor is located close to the analog circuitry in the center of the chip. The distance between microhotplate and circuitry is comparatively large owing to packaging requirements, as will be explained in Sect. 5.1.6. 

The methods of mechanical micromachining and micro EDM have been extensively applied to the fabrication of components such as micro heat exchangers, mixers, and reaction channels as well as chemical microsystems with integrated heat exchange, reaction, mixing, and distribution elements (Figure 10). 

While microscale devices and systems are typically fabricated from silicon, alternative materials are being examined as suitable supports. Microsystem features as small as 1 pm may be fabricated precisely by using a variety of etching, molding, and milling techniques. Since enzymatic reactions typically occur at moderate operating conditions (moderate pressures and ambient temperatures), plastics may be considered an inexpensive alternative to silicon for use as microreactor fabrication material. 

These current and potential applications motivate the development of techniques for fabricating and manipulating objects with nanometer and micrometer feature sizes. This review gives a brief introduction to materials and techniques commonly used for microfabrication its focus is on those currently being explored in our laboratory. Our aim is to illustrate how non-traditional materials and methods for fabrication can yield simple, cost effective routes to microsystems, and how they can expand the capabilities of these systems. In a concluding section we provide brief descriptions of a number of other techniques for fabrication that, like those we are developing, may provide variable alternatives to photolithography. 

Dario P, Cocco M, Soldani G, Valderrama E, Cabruja E, Meyer J-U, Giesler T, Beutel H, Scheithauer H, Alavi M, Burker V (1994) Technology and Fabrication of Hybrid Neural Interfaces for the Peripheral Nervous System. In Reichl H and Heuberger A. (eds) Microsystem Technology, p 417... 

Soper, S.A., Murphy, M.C., McCarley, R.L., Nikitopoulos, D., Liu, X., Vaidya, B., Barrow, 1., Bejat, Y., Ford, S.M., Goettert, 1., Fabrication of modular microsystems for analyzing K-ras mutations using LDR. Micro Total Analysis Systems, Proceedings 5th iTAS Symposium, Monterey, CA, Oct. 21-25, 2001. Kluwer Academic Publishers, Dordrecht, the Netherlands, 2001, 459-461. 

Moorthy, J., Beebe, D.J., In situ fabricated porous filters for microsystems. Lab-chip, 2003, 3, 62-66. 

Starkov V.V., Micro-Fabrication using Oxidized Porous Silicon. Nano- and Microsystems Engineering. N°2, 2005, pp. 24-28. 

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