Deep Reactive-Ion Etching

Fabrication was done by photolithography and deep reactive ion etching (DRIB). The catalyst was inserted by sputtering. Such a prepared microstructure was sealed with a Pyrex cover. The bonded micro device was placed on a heating block containing four cartridge heaters. Five thermocouples monitored temperature on the back side. A stainless-steel clamp compressed the device with graphite sheets. 

One way to fabricate such a reactor is by deep reactive ion etching (DRIE) with a time-multiplexed inductively coupled plasma etcher (most details on fabrication are given in [77]) [7, 77, 78]. Regions of major importance such as the retainers are etched through to avoid differences in stmctural depth which may cause uneven flow. To generate various channel depths in one design, both front-side and back-... 

The whole system is constructed from two silicon wafers, fabricated using photoresist by deep reactive ion etching (DRIB) [21]. The wafers were thermally bonded. Thereafter, inlet and outlet ports were machined and the single reactors isolated by DRIB. 

The device was realized by deep reactive ion etching (DRIE) using the SU-8 technique, producing vertical side walls [72-74]. This fabrication route was chosen to avoid crystallization, which is known to occur at sharp channel edges. Using DRIE smooth, curved corners can be realized, unlike by conventional silicon wet etching. 

FIGURE 18.2 Scanning electron micrographs of silicon microneedles, (a) Silicon microneedles micro-fabricated using a modified form of the BOSCH deep reactive ion etching process. The microfabrication process was accomplished at CCLRC Rutherford Appleton Laboratory (Chilton, Didcot, Oxon, UK). The wafer was prepared at the Cardiff School of Engineering, Cardiff University, UK. Bar = 100 pm (b-d) platinum-coated silicon microneedles prepared using a wet-etch microfabrication process performed at the Tyndall National Institute, Cork, Ireland. Bar = 1 mm (b), 100 pm (c,d). 

Fig. 12 Scanning electron microscopy (SEM) microphotographs of the walls and bottom of a hollow waveguide after the deep reactive ion etching process...

The most important process in the fabrication of silicon hollow fibers is deep reactive ion etching (DRIE). This process is very similar to the standard reactive ion etching (RIE) [ 122] process but permits us to achieve perfect vertical structures with low roughness. The results shown in Figs. 12 and 13 clearly confirm the required verticality of the walls to assure good confinement can be achieved. 

Ceriotti and Verpoorte [20] integrated a fritless column for NCEC with conventional stationary phases, which was used for the separation of fluorescein isothiocyanate (FITC)-labeled amino acids. The chips were fabricated in poly(dimethylsiloxane) using deep-reactive-ion-etched silicon masters. The... 

The mixers were fabricated by deep reactive ion etching (DR1E) into silicon [159], The silicon structure was anodically bonded to a glass wafer. 

The micro mixer was fabricated from two plates by standard MEMS technology, using deep reactive ion etching (DRIE) [48]. Anodic bonding is used for sealing the plates. 

Later, Pattekar and Kothare [21] presented a silicon reactor fabricated by deep reactive ion etching (DRIE). It carried seven parallel micro channels of 400 pm depth and 1 000 pm width filled with commercial Cu/ZnO catalyst particles (from Siid-Chemie) trapped by a 20 pm filter, which also was made by DRIE, in the reactor. The reactor was covered by a Pyrex wafer applying anodic bonding. Details of the reactor are shown in Figure 2.3. 

The reactor could be heated to 900 °C by applying these elements. The fabrication of the device was performed by deep reactive ion etching (DRIE) or KOH etching combined with silicon fusion bonding. 

The special issue of micro injection molding applied for polymer heat exchangers will not be considered here. Additionally, for MEMS-like systems discussed above, other techniques, mostly based on etching, e.g. deep reactive ion etching (DR1E), are applied [20, 71, 86]. These techniques allow for future mass production of the small-scale (sub-watt fuel processors) devices to which they are applied. 

Mehra, A., Ayon, A. A., Microfabrication of high-temperature silicon devices using wafer bonding and deep reactive ion etching, IEEE J. Microelectromech. Syst. 1999, 8, 152-160. 

DEP 4 DIN DMFC DNA DoE DRIE Dielectrophoresis Hydraulic diameter Deutsche Industrienorm Direct methanol fuel cell Desoxyribonucleic acid Design of experiments Deep reactive ion etching... 

Si02 Buffert hydrofluoric acid, RIE Dry etching, deep reactive ion etching DRIE Thermische thermal oxidation, low-pressure chemical vapor deposition Crystallographic and wet chemical etching of silicon... 

The devices are constructed from two plates, which are irreversibly joined by anodic bonding. M icrofabrication was achieved by means of deep reactive ion etching (DRIE) in borosilicate glass. 

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