Fire Risk Assessment and Mitigation for Semiconductor Manufacturing Equipment
(Factory Mutual Global, Rohnert Park, CA)
This paper begins with an overview of fire risks, highlighting the three elements of the fire triangle (fuel, oxidizer, and source of ignition) as the keys to understanding and mitigating fire risks in semiconductor process equipment. The assessment of risk, based on outcomes and their probabilities, is presented briefly. The criteria in SEMI S2-0200 Environmental, Health and Safety Guideline for Semiconductor Manufacturing Equipment are described. This recently-published version of S2 is less prescriptive than its predecessor (S2-93A), which results in the need for more thorough analysis, but permits a broader range of mitigation techniques. SEMI S14-0200 Safety Guidelines for Fire Risk Assessment and Mitigation is presented in greater depth. This latter Safety Guideline includes a detailed assessment process and criteria, which are intended to be used independently or in conjunction with the S2 assessment of equipment. The document also describes various available approaches to mitigation of fire risk (e.g., choice of materials of construction, separation of fuels from oxidizers, and suppression systems) and includes a general hierarchy of approaches (e.g., engineering controls are preferred to administrative controls), but allows for much professional discretion of the selection of fire risk mitigation methods by equipment designers. Lastly, some experiences from S14 evaluations will be described.