Conventional photolithography, technological

As glass and quartz exhibit the same surface property as fused-silica capillary, the monolithic materials could be conveniently prepared in a glass- or quartz-based microfluidic device via the same way of monoliths in the capillary. However, glass/quartz devices are rather expensive, and the need for specialized facilities for their fabrication with conventional photolithography technology hinders any rapid modification of the chip architecture. An attractive alternative is using a variety of polymeric materials, such as poly(dimethylsiloxane) (PDMS), poly(methyl methacrylate) (PMMA), polycarbonate (PC), and cyclic olefin copolymer (COC), to fabricate microchips for their mechanical and chemical properties, low cost, ease of fabrication, and high flexibility. 

The radiation sources employed in microlithography include conventional (>300 nm) and deep-UV (<300 nm) light, electron-beam, ion-beam and x-ray sources. By far the predominant lithographic technology is conventional photolithography which... 

Very low cost, medium performance printed electronics A less controversial area is printed (or organic) electronics. The objective in this rapidly developing field is to develop alternatives to silicon and conventional photolithography as the basis for electronic systems151"153. Initially, the devices produced using this technology would have relatively low performance, but very low cost. These devices would be directed toward applications (for example, RF ID tags154) where one-time use would dictate cost and performance. 

Over the last decade, printed electronics has received substantial attention as a potential application of inkjet technology. Conceptually, the goal is to use printing technology as a replacement for conventional photolithography-based semiconductor manufacturing. This is expected to result in a substantial cost reduction for the realization of simple semiconductor systems on cheap, flexible substrates such as plastic, steel foils, etc. 

Femtosecond laser applications, e.g., in electronic or medical technology require microstructuring on uneven substrates. This cannot be achieved by conventional photolithography which only functions on completely flat supporting materials. Ultraviolet lasers (excimer, fourth harmonic Nd YAG) have been widely used for such purposes. However, when high precision is required and substrates are extremely fragile and thermally sensitive, the very low heat effect by subpicosecond laser pulses can avoid this micromachining problem. 

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