Process tools are enclosed areas in which specific wafer processing functions occur. Any process tools handling flammable gases require a hazardous gas detection system to ensure safety and be in compliance to codes. The FM standard states that “ventilation shall be provided for all tools handling flammable and combustible liquids. Ventilation shall be provided to ensure the atmosphere does not exceed 25% of the LEL (LFL) in the event of the largest possible leak.”
Containers of hazardous gases, both flammable and toxic, are often isolated from the surrounding environment by safety enclosures (gas cabinets). Some process tools have a gas control enclosure section that serves the same purpose as a gas cabinet. It is important to monitor these enclosures for leaking gas to save product as well as prevent a toxic condition. The cabinets and enclosures are ventilated to prevent the buildup of any leaking gas.
Reliable gas detection and monitoring systems are an essential element of the semiconductor plant’s safety system. It requires gas detection systems that can accommodate a variety of combustible and toxic gas applications with both single and multi-sensor network solutions. A variety of systems are available for different monitoring applications. Using the correct system will result in managing gas hazards in the most effective and efficient way.
For the past couple weeks we shined the spotlight on the Pollution Control Industry; we've looked at the three ways to reduce emissions (Oxidizers, Incineration & Solvent Recovery). This week let's discuss HOW, by looking at real life applications:
Solvent recovery systems recover and re-use solvents from manufacturing processes. Solvent laden air from the processes is passed through an activated carbon bed. When the carbon bed is nearly saturated with solvent, a steam-down cycle occurs to condense out the solvent for re-use. The carbon is then regenerated for another collection phase. Two carbon beds are used so that one bed can process the solvent-laden air while the other one is regenerating.
It is becoming increasingly important to reduce emissions while saving energy when using a pollution control device such as a flare stack. Proper flare stack design is essential to handle their multiple waste streams for maximum performance with minimum emissions. Since destruction efficiency and emissions (both visible and invisible) are some of the most important criteria to consider when designing a flare, when the design is done correctly, dramatic money savings will also be realized.
A flame ionization detector at the outlet of the oxidizer ensures that it does not exceed emission levels. In addition, by using two flame ionization detectors, one on the inlet and one on the outlet, hydrocarbons can be measured and compared before and after processing, indicating efficiency.
