Chip manufacture, electrochemical

Figure 4-3 shows the broad range of time and length scales— some 15 orders of magnitude or more—that are encountered for one particular field of application involving electrochemical processing for chip manufacture. The figure is divided into three vertical bands in which different kinds of numerical simulation... 

Schematic of the time and length scales encountered in multiscale simula-electrochemical processing for chip manufacture.

The device was manufactured as two parts the first part is a disposable silicon chip - with the electrochemical cells arrays. The sihcon chip was wire bonded to a special printed circuit board (PCB) platform, which was directly connected to the data processing units. The second part of the device is reusable, which includes a multiplexer, potentiostat, temperature control and a pocket PC for sensing and data analysis (for more details see [5]). This design enables performance of multi experiments simultaneously and each electrochemical cell can be measured independently. The total weight of the entire system is -900 g, making it ideal for medical applications. 

Electrochemistry is a central theme in the interconnection of chips and other microelectronic components. The manufacture of printed wiring boards, such as single-layer, multilayer, or flexible boards, involves electroplating of the conductor that forms the electrical paths. The corrosion of these paths and the interfacial stability of the conductor-polymer composites that determine the reliability of these interconnections are electrochemical problems. 

FIGURE 12.14 Schematic of various microfabricated electrode array devices manufactured by ABTECH Scientific, Inc. (A) Interdigitated microsensor electrodes (IMEs), (B) independently addressable microband electrodes (lAMEs), (C) independently addressable interdigitated microsensor electrodes (lAIMEs), (D) microdisc electrode array (MDEA), and (E) electrochemical cell-on-a-chip MDEA (ECC MDEA 5037). 

Electrochemical (EC) detection is particularly well suited to capillary electrophoresis. In contrast to many optical methods, EC detection can be miniaturized without a loss of sensitivity. It is very selective because there are few compounds in biological samples that are electroactive. The selectivity is tunable and dependent on the electrode material and the applied potential. Modified electrodes and multiple electrode systems can be used to increase selectivity for certain classes of analytes. Electrodes and potentiostats can also be integrated into chip-based CE systems using procedures similar to those employed for the manufacture of the analytical chips. 

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