Fabrication of Microdevices

Microfluidics is the key to NLC and NCE, the miniaturized microfluidic system that can automatically carry out all the necessary functions to transform chemical information into electronic information. The first p.-TAS device was developed by Terry et al. [23] for gas chromatography, which did not gain popularity at that time, probably due to poorly developed microfluidic devices. In 1990, Manz et al. [24] introduced the concept of p.-TAS. Nowadays, fx-TAS is a popular development in various disciplines and has been reviewed by Manz and coworkers [25-28]. 

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The latest advancement in femtosecond (fs)-based micromachining technology has opened a new window of opportunity for fabrication of microdevices. Direct exposure of most solid materials (including fused silica glass) to high power fs laser pulses may lead to the ablation of a thin layer of materials at the laser focal point13. Due to the multiphoton nature of the laser-material interaction, the ablation process can be conducted on the material surface as well as within its... 

The concept of a "minimum feature size is also important in fabrication of microdevices its actual dimensions are determined by the choice of fabrication process. As discussed below, conventional photolithography (405 or 436 nm) is generally limited to features of approximately 1 pm. Deep ultraviolet (UV) (230 to 260 nm) lithography has a minimum feature size of 0.3 pm, and x-ray and e-beam can be used to generate features as small as 0.1pm. 

In the past 15 years, the use of microfluidic devices for chemical analysis has increased tremendously. Indeed, a broad range of chromatographic and electrophoretic separation methods have been implemented in microchips. However, for widespread utilization of microfabricated devices in analysis applications, particularly in the field of proteomics, further efforts are needed to develop simple fabrication techniques that achieve functional integration of multiple tasks in a single device. " In this section, we describe the fabrication of microdevices using sacrificial materials and discuss some of the advantages of this approach over conventional microfabrication methods. 

The lithographic process that is widely used to generate microstructures, especially in the context of the fabrication of microdevices, is shown schematically in Fig. 9.1. It is based on the interaction of electromagnetic or particle radiation with matter. Since direct irradiation of the substrate (e.g., silicon wafers) does... 

Past efforts to improve the fabrication of microdevices have been closely connected with attempts to increase the resist sensitivity, S. In the case of the resists described in Section 9.1.3.1, S is limited by the quantum yields, which are much low-... 

Planar lithography techniques are not effective for precise fabrication of microdevices with hemispherical shapes (17). Drop-on-demand inkjet printing of a photocurable ink is a more appropriate approach as it takes advantage of the surface tension as well as of the delivery of a well-defined ink volume. 

Zwicker, G., 2008. Fabrication of microdevices using CMP. In li, Y. (Ed.), Microelectronic Applications of Chemical Mechanical Planarization. Wiley Intersdence, Hoboken, pp. 401-429. 

This chapter introduces different fabrication methodologies of microdevices. Different functional materials used in these devices are discussed first. Subsequently, different steps adopted for photolithography-based micromanufacturing are discussed next. This is followed by the plastic-based micromanufacturing process. Subsequently, the laser-based microfabrication is introduced. Finally, different bonding processes adopted during fabrication of microdevices are discussed. 

Chemical Amplification All resists must comply with numerous additional requirements, referring among others to radiation sensitivity, resolution, contrast, aspect ratio, line edge roughness (LER), heat resistance, and shelf-life. With regards to the large-volume fabrication of microdevices, chemical... 

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