Managing Process Byproduct Hazards within Centralized Exhaust Systems
Roberts, Thomas M.
(Micron, Boise, ID)
The wafer fabrication industry may have well-developed process safety assessment procedures with respect to evaluation of process hazards specific to wafer fabrication equipment and secondary systems supporting wafer fabrication. Secondary systems include centralized exhaust systems that are designed to support wafer manufacturing equipment. Centralized exhaust systems may be identified as low risk systems based on a standard hazard review. Risks associated with a centralized exhaust system include the potential to form deposits of reactive byproducts within the system. These risks are typically managed through practices of segregating incompatible emissions and implementing point of use abatement at point of generation. Managing the hazards of reactive byproducts within a centralized exhaust system should include implementing process safety principles through the entire life of the system. Applicable process safety principles include managing asset integrity and reliability through the life of the system. Formation of reactive byproducts within a centralized exhaust system should be assessed and evaluated on a periodic basis. The formation of reactive byproducts within a centralized exhaust system may be a risk over the life of a system due to periodic equipment failures or from low level emissions from treated sources. This article presents a general discussion of potential hazards associated with process byproducts within centralized exhaust systems. The article provides an overview of test methods to evaluate reactivity, thermal stability, toxicity, and flammability of process byproducts. Assessment methods are presented to aid in evaluating the hazards associated with byproduct deposits. The article suggests a risk-based approach to evaluating hazards and implementing controls to reduce the risk associated with byproduct deposits within a centralized exhaust system.