Micromachining methods

Three-dimensional electrode arrays have been fabricated using two very different micromachining methods. One approach, named carbon MEMS or C-MEMS, is based on the pyrolysis of photoresists. The use of photoresist as the precursor material is a key consideration, since photolithography can be used to pattern these materials into appropriate structures. The second approach involves the micromachining of silicon molds that are then filled with electrode material. Construction of both anode and cathode electrode arrays has been demonstrated using these microfabrication methods. 

Describe live micromachining methods for making polymeric chips. (5 marks)... 

The book is divided into several chapters which include micromachining methods, microfluidic operations (microfluidic flow, sample introduction, sample preconcentration), chemical separations, detection technology, and various chemical and biochemical analysis (applications on cellular analysis, nucleic acid analysis, and protein analysis). Emphasis will be placed on analytical applications although the basic principles about micromachining and fluid flow and control will also be covered only to the extent that their understanding will assist the exploitation of the microfluidic technology on analytical applications. 

Micromachining methods such as photolithographic patterning and selective etching that evolved from the realm of integrated circuits have enabled the fabrication of 3-D Microsystems. 

The majority of the fabrication techniques used to manufacture pTAS or Lab-on-a-Chip devices has been developed from the microelectronics industry. A wide range of techniques are available and a comprehensive treatment is beyond the scope of this article. A typical device consists of two layers or plates the base plate and the cover plate. The channel network is formed in the base plate by a suitable micromachining method. The network is closed by the cover plate, which also contains the fluid transfer connections or the reservoirs and possibly the electrodes. The two plates are either pressed firmly together or irreversibly bonded to form liquid tight seals. A diagram of a typical device can be seen in Figure 1. Devices with multiple channel layers are... 

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