Polystyrene electron resist material

Recently chloromethylated polystyrene (CMS), a highly sensitive, high resolution electron resist with excellent dry etching durability, was developed. Very recently reactive intermediates in irradiated polystyrene, which is a starting material of CMS, have been studied and the transient absorption spectra of excimer (2-4), triplet states (2,5), charge-transfer complexes, and radical cations (6) of polystyrene have been measured. The present paper describes the cross-linking mechanism of the high sensitivity CMS resist and compares it to that of polystyrene on the basis of data on reactive intermediates of polystyrene and CMS. 

Jt OLYSILOXANES WITH PENDANT SIDE CHAINS are interesting materials from both the theoretical and practical points of view. A number of polysiloxanes with various side chains, such as liquid crystals (i, 2), carbazole groups (3), electron-donor and electron-acceptor groups (4), polystyrene (5), and functional groups (hydroxyl or carboxyl) (6), have been synthesized. Polysiloxanes are known for their useful properties, which include flexibility, heat resistance, water repellence, and biological inertness. These properties, combined with the ease with which a tailored polymer structure can be prepared,... 

Syndiotactic polystyrene (sPS) represents an important achievement in olefin polymerization catalysis. Syndiotactic PS is an industrially relevant thermoplastic material produced by Dow Chemical and Idemitsu Kosan Co. under the tradenames Questra and Xarec , respectively. Industrial interest on sPS originates from the remarkable properties exhibited by this highly crystalline polymer. The high melting temperature, 270 °C, the relatively fast crystallization rate (at least much faster than that of iPS), the high heat resistance, the low dielectric constant, the high elastic modulus, and an excellent resistance to chemicals explain the industrial interest for this material. Syndiotactic PS was considered as an innovative new resin option for the automotive, electrical, and electronic markets, appliances such as... 

Polystyrene (PS) foam is only accepted as packaging material for electronic components if the electrical resistivity is low enough to prevent components damage due to electro-static charges. Anti-static additives are added to PS foam batches to reduce static charge and discharge effects to an acceptable level but reliable electrical resistivity values of such foams were not available. Hence, a series of measurements was performed to determine such values. 

When some or all of the phenyl rings are substituted with halogen (Scheme 6.11), the radiation sensitivity and the cross-linking efficiency of polystyrene can be enhanced significantly. Negative electron-beam resist formulated from iodi-nated and chlorinated polystyrene and based on this approach have been reported. Sensitivity of about 2 p.C/cm and resolution of about 1-p.m features have been demonstrated with these materials. ... 

Expanded polystyrene foam is used for thermal insulation and as a packaging material. It is often used for food trays. Polystyrene can also be crosslinked. Cross-linked polystyrene parts are often used in low-loss electrical and electronic applications requiring moderate resistance to temperature. 

Syndiotactic polystyrene (sPS) is a relatively new material discovery in semicrystalline pol5nners with a high melting point and rapid crystallization rate, which makes it possible to injection mold the material. The stereospecific polymerization was made possible by the combination of a transition metal catalyst with weakly coordinating cocatalysts, such as methylaluminoxane. The excellent balance of mechanical, electrical, solvent resistance, and dimensional stability properties combined with a relatively low price (based on styrene monomer) have made this material a competitor to existing engineering plastics. The products also have excellent heat performance and are finding application in antomotive (under the hood), electrical, and electronic connector systems. 

In order to conduct electricity, greater or lesser free motion of electrons in the material is required. However, electrical behavior involves questions not only of conduction and resistance but of static charges. Most polymers are insulators, except if they have alternating double and single bonds see Section 14.7.3. The motion of electrons in polymers, and in materials generally, also affects thermal conductivity. Thus good electrical insulation and good thermal insulation (low coefficient of heat transfer) are closely related physically. That is why pots are made out of metal, but pot handles are made out of plastic. Lack of electron-free motion also contributes to transparency in pure, amorphous plastics such as polystyrene and poly(methyl methacrylate). 

Polystyrene is a glasslike solid below 100 °C. Below this temperature it shows considerable mechanical strength. Rubber-modified polystyrene is a two-phase system, rubber dispersed in polystyrene being the continuous phase. Advantage is taken of the complex interaction of those systems in many applications in which high stress-crack resistance is needed. Polystyrene is nonpolar, chemically inert, resistant to water, and easy to process. It is the material of choice for many food-packing, optical, electronic, medical, and automotive applications. Tensile strength can be increased by controlled orientation of polystyrene. 

The most important commercial polymer is a blend of poly[oxy-(2,6-dimethyl-phenylene)] with high-impact polystyrene (HIPS). The corresponding material exhibits variable characteristics, depending on the PS content. It is a widely used technical polymer in mechanical engineering. Indeed, it exhibits a good impact resistance at very low temperatures in addition to its good thermal and mechanical properties. Its marked electrical insulating character even in wet atmospheres finds applications in electric and electronic industries. 

Several plastics exhibit especially outstanding properties. For applications in which optical transparency is critical, polystyrene and poly(methyl methacrylate) are especially well suited however, it is imperative that the material be highly amorphous or, if semicrystalline, have very small crystallites. The fluorocarbons have a low coefficient of friction and are extremely resistant to attack by a host of chemicals, even at relatively high temperatures. They are used as coatings on nonstick cookware, in bearings and bushings, and for high-temperature electronic components. 

HIPS (High impact polystyrene) - the major application for this plastic is in the packaging industry, where low cost and rigidity are economically emd technically vital. The material has a tendency to yellow and shows very poor mar resistance. The most important application for the coating supplier is the widespread use of this plastic in the consumer electronics industry. Electrical insulation properties are good and cost is low. 

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