Photodefinable

Polyimides, both photodefinable and nonphotodefinable, are coming iato iacreased use. AppHcatioas iaclude planarizing iatedayer dielectrics oa iategrated circuits and for interconnects, passivation layers, thermal and mechanical stress buffers ia packagiag, alpha particle barriers oa memory devices, and ion implantation (qv) and dry etching masks. 

Jackman, R. J., Floyd, T. M., Ghodssi, R., Schmidt, M.A., Jensen, K. F., Microfluidic systems with on-line UV detection fabricated in photodefinable epoxy, J. Micromech. Microeng. 11 (2001) 263-269. 

A novel, photodefinable, polymeric material was formulated to meet the needs of a particular circuit technology. Rubber modification of a thermoset resin with good thermal, chemical, and electrical properties generated a formulation that met stringent processing and reliability requirements. 

A number of reviews have appeared of topical interest. These include photoisomerism of azo dyes, ° photofunctional polysilanes,photochromic pigments, rare earth complexes, pressure sensitive paints, electron-transfer processes,electroactive dendrimers, chiral polyisocyanates, photodefin-able benzocyclobutene, photoconductive polymers,excited states in conjugated polyenes, photosensitive materials and polyazomethanes. ... 

Reports of new materials and formulations and resin properties are prolific. Articles of a topical or applied interest include probes for in-situ hardness measurements on adhesives, photobase generators for image recording devices, oxygen inhibition in packaging applications, resins for sign boards, potentiometric sensors, new photodefinable polyimides, visible curable resists, " clay composites, putties, silica fillers, curable paints, soluble photocurable systems, fluorinated coatings and in-... 

The major drawback of these techniques was the high production cost of the substrates and the requirement of microfabrication in a clean room facility, not affordable for disposable microfluidic devices, and this consideration led the researchers to investigate the possibility of using of photodefinable polymers, converting conventional photoresists that have been already used for patterning, in the microelectronics industry into structural elements of microfluidic devices. 

R. J. Jackman, et al.. Microfluidic Systems with On-line UV Detection Fabricated in Photodefineable Epoxy. J. Micromech. Microeng., 2001, 11, 263-269. 

Although, AIN fares well in terms of thermal conductivity, its dielectric permittivity is rather high. As polymeric materials such as polyimide possess e-values as low as 2.5, and are photodefinable, AlN/polyimide substrates with high thermal conductivity and low dielectric permittivity for combined thermal and signal delay management are now available. 

Enthone-OMI Envision PDD-9015 photodefinable liquid dielectric MacDermid MACu Via-C photodefinable liquid dielectric... 

Figure 4. Photopatterningprocess by using photodefinable reactive polymer. (Highlighted in Analytical Chemistry,...

Scanning probe microscopy techniques have been used to characterize surfaces related to the processing of benzocyclobutene (BCB) dielectric thin films. Thermally cured resins and photodefinable resins are used... 

Due to various problems, no such depolymerization-based resist has found widespread use in optical lithography. However, depolymerization schemes have been exploited to some degree in e-beam resists as will be discussed later. Such materials have also been utilized as the basis for photodefinable sacrificial materials for microfluidic and MEMS device fabrication,... 

Via Capture Pad 4 mils Larger than Via Diameter Photodefined... 

FIG. 11A Cummulative failures of photodefined microvias ranging in diameter from 3 to 8 mils,... 

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