Etching polymers listed

Dry-etch selectlvlties for several negative e-beam resists are also listed in Table V. They are more resistant than the positive e-beam resists of the Table except PMCN and the positive photoresists, AZ2400 and PC 129. The positive-behaving vinyl polymer resists tested are generally less resistant than the negative-behaving systems. This generality, however, does not hold for the photoresists tested, as the data of Table VII verifies. 

Polymeric membranes are prepared from a variety of materials using several different production techniques. Table 5 summarizes a partial list of the various polymer materials used in the manufacture of cross-flow filters for both MF and UF applications. For microfiltration applications, typically symmetric membranes are used. Examples include polyethylene, polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE) membrane. These can be produced by stretching, molding and sintering finegrained and partially crystalline polymers. Polyester and polycarbonate membranes are made using irradiation and etching processes and polymers such as polypropylene, polyamide, cellulose acetate and polysulfone membranes are produced by the phase inversion process.f Jf f ... 

Table 2 provides a list of materials, and gases used for etching these materials. Silicon, oxide and metal are among the most important materials in microelectronics. Salient features of etching these materials are discussed below. Etching of other materials such as compound semiconductors [209], polymers [210] and other metals [211] is also of importance. 

The list of polymers known to respond satisfactorily to permanganic etching is now long and continually growing. It consists of linear and branched polyethylene, four isotactic polyolefins (polypropylene, polystyrene, poly(4-methylpentene-l) and poly(butene-l)), related atactic polymers, poly(vinylidene fluoride) (hereafter denoted PVF2), PEEK, and poly(ethylene terephthalate) (PET), together with various copolymers and others such as ethylene propylene rubbers and ethylene-propylene-diene (EPDM) terpolymer. 

It is now known that a wide array of polymers can be etched using potassium permanganate [273] although some care must be taken to limit the effect of artifacts. The list includes linear and branched PE, PP, PS, poly(4-methylpentene-l), poly (butene-1), PVF2, PEEK, PET and various copolymers such as EPDM terpolymers [273]. More recent work has shown that even liquid crystalline polymers can be etched by a variation of this method. Controls and complementary microscopy are essential to ensure that the experimentalist is not led astray imaging artifacts, hills and valleys or nussing fine structure, lost in the wash baths. 

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