Using a modified Hazop/FMEA methodology for assessing system risk

As semiconductor manufacturing processes become more complex and the costs associated with manufacturing line downtime soar, the reliability of the supporting systems have become a major area of focus. Preventive and predictive maintenance, real time system status monitoring, and periodic inspections are typical methods used to help reduce unexpected system failures. Although these methods are proactive, they are typically applied on the basis of perceived risk or solely on the historical perspective of the designer or owner. Utilization of a robust and flexible system risk assessment method early in the design phase is a highly effective approach to increasing system up time and identifying design weaknesses. This paper will present a risk assessment approach based on strengths of both hazard and operability study (Hazop) and failure mode and effects analysis (FMEA) methodologies