Printing photolithographic technique

This type of coil was prepared from copper cladded printed circuit board material by applying photolithographic techniques. The p.c. board material is available with difierent copper thicknesses and with either a stiff or a flexible carrier. The flexible material offers the opportunity to adapt the planar coil to a curved three dimensional test object. In our turbine blade application this is a major advantage. The thickness of the copper layer was chosen to be 17 pm The period of the coil was 100 pm The coils were patterned by wet etching, A major advantage of this approach is the parallel processing with narrow tolerances, resulting in many identical Eddy current probes. An example of such a probe is shown in fig. 10. 

Recently it has been shown that hydrogel layers of variable thickness can be prepared on solid substrates by photolithographic technique [47], The technique called PRINT (particle replication in non-wetting templates) [48,49] utilizes elastomeric molds from a low surface energy perfluoropolyether network. The molds prevent the formation of an interconnecting film between molded objects and allow production of monodisperse microgel particles of different sizes, shapes, compositions, and surface functionalities. 

Essentially two fabrication approaches exist, leading to microarrays with different properties. In one approach, customized cDNA probes are prepared separately and then mechanically spotted on the support, with a density of about 10,000 spots/cm [52,53]. Because of errors in the handling and printing of probes, this procedure is prone to erroneous arraying [54]. The second approach uses photolithographic techniques to carry out the parallel synthesis of the oligonucleotides directly on the surface [55,56]. The length of the probes is typically for only 14 to 25 bases, much shorter than for... 

Copper conductors can be deposited and defined in either one of two processes thick-film screen printing and etched thick film. In the former process, thick-film inks are forced through a screen in a definite pattern, dried, and fired. In the latter process, a blanket coat of conductor ink is applied to the ceramic with a screen and fired. It is then etched to the final pattern using classical photolithographic techniques. Line widtirs in tiiis etch process can be as narrow as 0.001 in., whereas the classical screen-printed conductor can only be as narrow as 0.004 in. 

Another important issue in polymer electronics is the possibility to prepare integrated circuits with a different approach with respect to conventional semiconductors. Instead of using vacuum deposition and photolithographic techniques, which are very expensive, integrated circuits can be manufactured by cheap methods based on solution processing. In this way, ink-jet printed (UP) devices with 20 /rm... 

Contact printing also gives the best reproduction of the mask pattern, in favourable conditions, and produces the highest resolution possible in photolithographic techniques. The theoretical resolution... 

Different approaches have been reported for enzyme immobilization and membrane deposition including drop-on techniques [42, 51], ink-jet printing [52] and photolithographically patterned enzyme membranes [53,54]. 

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