Corrosive Fume Exhaust Ducts

Teflon by EMPICO industrial coatings have become an indispensable material for engineers in the chemical exhaust industry, thanks to these unique properties:

• Excellent chemical resistance
• High temperature resistance
• Nonstick
• Tough
• Nonwetting
• Electrically non-conductive

Computer chips and other semiconductor devices are manufactured using multiple etching processes that involve a variety of acids, bases and other types of chemicals. The residual chemicals and those generated as by-products of the etching process have to be exhausted from the reaction chambers and transported to an environmental cleanup operation before disposal. A Corrosive Fume Exhaust System is a complex series of interconnected ducts that perform this function. Starting at a specific etchant tool, the corrosive exhaust is blended with that from the next and other subsequent chamber chemicals into a sub-header duct, several of which can be up to 13 feet in diameter. Thus, the purest of chemicals that do the actual etching end up as a witch’s brew further downstream.

As the world becomes increasingly digitalized, semiconductor manufacturers have responded by using more concentrated chemicals and higher etching temperatures to increasingly severe demands on the exhaust duct systems. For personnel health and safety reasons, no leaks can be tolerated. Furthermore, insurance companies are pressing for improved fire safety regulations, and are promoting duct products that meet stringent fire-resistance standards. Since the cost of lost production can be staggering in this competitive industry, semiconductor OEMs willingly endorse improved technology.

Teflon ETFE is used to coat the interior surfaces of stainless-steel ducts. ETFE is a tough polymer that can withstand rough handling during installation. Its excellent adhesion allows field modifications which include various taps as well as cutting the ducts to specific lengths and re-flanging them. ETFE has excellent resistance to the chemicals used in this industry. With a continuous operating temperature of 150 C/300 F, ETFE can withstand the high temperature chemical exhausts from the etchant chambers. Because ETFE does not burn easily, stainless-steel ducts coated with Teflon ETFE can be manufactured to pass the Factory Mutual FM-4922 fire resistance test.