Polymeric resists, performance

In addition to their exceptional tensile strengths, PAN-based carbon fibers are far more resistant to compressive failure than are their pitch-based counterparts or polymeric high-performance fibers. However, because the PAN precursor is not... 

The fabrication of PEDOT nanofiber, nanotube and nanowire has been mainly focused on the AAO membrane, because AAO has advantages such as rigid shape, uniform diameter, and various pore sizes [364-368]. Electrochemical polymerization was performed in the pores of AAO membrane using SDS, LiC104 and EDOT solution and measured the resistance of the PEDOT nanofiber with a diameter of 35 nm and 150 nm, respectively. The resistance of PEDOT nanofiber was between 1.5 K and 300 K and the resistance ratio of R(T)/R (300 K) was the relevant term to investigate the intrinsic electrical properties of the conducting polymer. The resistance ratio increased... 

The solubility of the PAG in the solid polymeric matrix can influence CA resist performance (63). This is a particular issue for the ionic oniiun salts if the polarities of polymer and PAG are sufficiently different, phase segregation will occur, and the poor mixing of photoacid and polymer effectively reduces the efficiency of catalyzed deprotection. Additionally, resist contrast can be affected when the solubility of the photoproducts differs from that of the original onium salt. In fact onium salts can serve as dissolution inhibitors in novolac polymers, analogous to diazonaphthoquinones, even in the absence of any acid-sensitive chemical function on the poljuner (27). 

The first series of products developed and commercialized were the solvent processable resists called RISTON I. A 24" wide conveyorized spray developer was fabricated that used 1,1,1-trichloroethane (methyl chloroform) as the developing solvent. After development, the PWB panel was then ready for etching or electroplating. Following that, it was necessary to strip away the polymerized resist. Methylene chloride or azeotropes with methanol were the iiutial stripper chemistries and DuPont fabricated 24" conveyorized equipment to perform that operation. The developer and stripper equipment both fabricated from stainless steel, required in-line solvent stills that would continuously feed a fresh supply of clean distillate solvent through a series of spray chambers and in a counter flow direction to that in which the boards were traveling. Smaller fabricators often stripped using a series of dip tanks. 

ADMET is quite possibly the most flexible transition-metal-catalyzed polymerization route known to date. With the introduction of new, functionality-tolerant robust catalysts, the primary limitation of this chemistry involves the synthesis and cost of the diene monomer that is used. ADMET gives the chemist a powerful tool for the synthesis of polymers not easily accessible via other means, and in this chapter, we designate the key elements of ADMET. We detail the synthetic techniques required to perform this reaction and discuss the wide range of properties observed from the variety of polymers that can be synthesized. For example, branched and functionalized polymers produced by this route provide excellent models (after quantitative hydrogenation) for the study of many large-volume commercial copolymers, and the synthesis of reactive carbosilane polymers provides a flexible route to solvent-resistant elastomers with variable properties. Telechelic oligomers can also be made which offer an excellent means for polymer modification or incorporation into block copolymers. All of these examples illustrate the versatility of ADMET. 

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