Resist development commercial developers

The most chemical-resistant plastic commercially available today is tetrafluoroethylene or TFE (Teflon). This thermoplastic is practically unaffected by all alkahes and acids except fluorine and chlorine gas at elevated temperatures and molten metals. It retains its properties up to 260°C (500°F). Chlorotrifluoroethylene or CTFE (Kel-F, Plaskon) also possesses excellent corrosion resistance to almost all acids and alkalies up to 180°C (350°F). A Teflon derivative has been developed from the copolymerization of tetrafluoroethylene and hexafluoropropylene. This resin, FEP, has similar properties to TFE except that it is not recommended for continuous exposures at temperatures above 200°C (400°F). Also, FEP can be extruded on conventional extrusion equipment, while TFE parts must be made by comphcated powder-metallurgy techniques. Another version is poly-vinylidene fluoride, or PVF2 (Kynar), which has excellent resistance to alkahes and acids to 150°C (300°F). It can be extruded. A more recent development is a copolymer of CTFE and ethylene (Halar). This material has excellent resistance to strong inorganic acids, bases, and salts up to 150°C. It also can be extruded. 

Methods 1 and 3 have been utilized in dry developed resist systems. To our knowledge, there are no resist systems commercially available that depend on post-exposure treatment other than the post-curing effect in negative electron beam resists mentioned earlier. Since such systems are still largely in the research phase we will not discuss them here but rather refer the reader to the literature for more detailed descriptions (44-50). 

The 1990s saw the introduction of commercial water-hased top antireflection coating materials that do not require a solvent treatment hut are removed during normal resist development in 0.26 N aqueous tetramethyl ammonium hydroxide developer solution or simply dissolved with a water rinse. Specifically, they were introduced at 248-nm wavelength (KrF) lithography, with the first chemically... 

Since its first commercial use in 2001, there have been no reports of reduced pathogen sensitivity to zoxamide. Laboratory studies to investigate the potential for resistance development to the benzamide class have been carried out with zoxamide [24], and zarilamide [25], a benzamide that binds to the same site as zoxamide on jS-tubulin [7]. In these studies, attempts to isolate resistant mutants in different Oomycetes using chemical mutagenesis, UV irradiation or adaptation were unsuccessful. These results suggest that the risk for resistance development to zoxamide in its commercial target pathogens is relatively low. 

Hypochlorite-resistant cathodes. Commercialization of activated cathodes for diaphragm cells has been hampered because hypochlorite corrodes steel under open-circuit conditions (Section 4.6). In the process, the coating spalls off or loses its activity. Development of resistant coatings for steel or other substrates could render the cathode immune during shutdowns. 

Styrene—acrylonitrile (SAN) copolymers [9003-54-7] have superior properties to polystyrene in the areas of toughness, rigidity, and chemical and thermal resistance (2), and, consequendy, many commercial appHcations for them have developed. These optically clear materials containing between 15 and 35% AN can be readily processed by extmsion and injection mol ding, but they lack real impact resistance. 

The commercialization by Kureha Chemical Co. of Japan of a new, highly attrition-resistant, activated-carbon adsorbent as Beaded Activated Carbon (BAC) allowed development of a process employing fluidized-bed adsorption and moving-bed desorption for removal of volatile organic carbon compounds from air. The process has been marketed as GASTAK in Japan and as PURASIV HR (91) in the United States, and is now marketed as SOLD ACS by Daikin Industries, Ltd. 

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