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| WAFER PROCESSING COMPONENTS | ETCH EQUIPMENT
In dry processing (i.e. gas plasma etching and stripping), the high temperatures and exposure to aggressive gas plasma, requires the use of polyimide and/or polybenzimidazole. In applications that directly contact the wafer surface, immidized plastics have the high purity needed to prevent contamination of the wafer. In addition to Celazole, Port Plastics offers a series of high purity products that provide performance over a broad range of temperatures. See Tables 1, 2 and 3 for more information regarding the purity of DSM's products. Polycarbonate is another product that is often used as a viewing "window" in dry process chambers. Polycarbonate has the least amount of ionic impurities of any thermoplastic shape, and is used in applications where the thermal conditions do not exceed 300°F (150°C). 
DuratronTM XP High purity polyimide
Unreinforced Duratron XP polyimide is produced from high purity resin with very low ionic impurities and outgassing rates. It is well suited for structural and electrical applications where maintaining purity or electrical insulation is critical. - Heat resistance to 575°F (303°C)
- Very low level of ionic impurities
- Minimal outgassing, even at elevated temperatures
Celazole* PBI Unreinforced polybenzimidazole - High purity
- Highest heat resistance (800°F/427°C) with excursions possible to 1,000°F (538°C)
- Lowest coefficient of linear thermal expansion
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