SEMI E124 - Guide for Definition and Calculation of Overall Factory Efficiency (OFE) and Other Associated Factory-Level Productivity Metrics
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This Guide describes metrics that show how well a factory is operating compared to how well it could be operating (for the given product mix). These metrics can be used for tracking factory performance (in value-added production) in a way that rewards good operational decisions and that is not easy to adversely manipulate. The metrics can be used in a process of ongoing improvement that can be visible to all levels of a semiconductor manufacturing organization.
The metrics in this Guide are intended for evaluating the relative efficiency of factory production after the factory is in production, not for capacity analysis while the factory is being designed or redesigned. However, some of these metrics can be used in factory simulations for choosing equipment sets and scheduling policies.
To evaluate the overall effectiveness of a factory, there are at least three things in need of measurement: production, utilization of assets, and costs. This Guide focuses on evaluating production. Utilization of assets and costs (as well as other economic factors) are outside its scope.
This Guide describes metrics for an entire integrated production line (so, for example, lots may not leave and then return to the production line). Multiple production lines in the same factory may be evaluated separately if they do not share resources (such as material handling or production equipment).
Referenced SEMI Standards
SEMI E10 — Specification for Definition and Measurement of Equipment Reliability, Availability, and Maintainability (RAM) and Utilization
SEMI E35 — Guide to Calculate Cost of Ownership (COO) Metrics for Semiconductor Manufacturing Equipment
SEMI E58 — Automated Reliability, Availability, and Maintainability Standard (ARAMS): Concepts, Behavior, and Services
SEMI E79 — Specification for Definition and Measurement of Equipment Productivity
SEMI E116 — Specification for Equipment Performance Tracking
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