SEMI E10 - Specification for Definition and Measurement of Equipment Reliability, Availability, and Maintainability (RAM) and Utilization -

Member Price: $267.00
Non-Member Price: $355.00

Volume(s): Equipment Automation Hardware
Language: English
Type: Single Standards Download (.pdf)
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Revision: SEMI E10-0422 - Current





This Specification provides a standardized methodology for measuring reliability, availability, and maintainability (RAM) and utilization performance of equipment in a manufacturing environment. It applies to all equipment systems, which includes equipment modules, noncluster tools, single and multipath cluster tools, and more. By establishing standard measurement methods, terms, and calculations, SEMI E10 improves communication between users and suppliers and enhances the manufacturing capability of semiconductor and related industries.



This Specification establishes a common basis for communication between users and suppliers of manufacturing equipment in the semiconductor and related industries by providing a standardized methodology for measuring reliability, availability, and maintainability (RAM) and utilization performance of equipment in a manufacturing environment.


This Specification defines six mutually exclusive, basic equipment states for all of the conditions and associated periods of time for an equipment system during an observation period. One equipment state called the unscheduled downtime state (UDT) defines a ‘failed’ condition for an equipment system. The measurement of equipment system reliability in this Specification concentrates on the relationship between equipment system failures and equipment system usage.


All metrics defined herein are applicable to equipment systems that include subsystems, noncluster tools, single-path cluster tools (SPCTs), equipment modules within a multipath cluster tool (MPCT), intended process sets (IPSs) of equipment modules, and MPCTs. This Specification defines a treatment of RAM and utilization measurement for MPCTs by first defining performance of IPSs as a function of equipment module-level performance, then defining MPCT performance as a function of IPS performance. For each metric presented, any special handling required for IPSs and MPCTs is defined.


This Specification defines basic metrics for:

  • Reliability — Including mean time between failures (MTBF), mean cycles between failures (MCBF), and mean work between failures (MWBF).
  • Availability — Including total uptime, operational uptime, equipment-dependent uptime, and supplier-dependent uptime.
  • Maintainability — Including mean time to repair, mean time to (perform) preventive maintenance, mean time offline, total failure rate, and impairment rate.
  • Utilization — Including total utilization and operational utilization.


Referenced SEMI Standards (purchase separately)

SEMI E30 — Specification for the Generic Model for Communications and Control of Manufacturing Equipment (GEM)

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


Revision History

SEMI E10-0422 (technical revision)
SEMI E10-0221 (technical revision)

SEMI E10-0814E (editorial revision)

SEMI E10-0814 (complete rewrite)

SEMI E10-0312 (complete rewrite)

SEMI E10-0304E (editorial revision)

SEMI E10-0304 (technical revision)

SEMI E10-0701 (technical revision)

SEMI E10-0301(technical revision)

SEMI E10-0600 (technical revision)

SEMI E10-0699E (editorial revision)

SEMI E10-0699 (technical revision)

SEMI E10-0299 (technical revision)

SEMI E10-96 (technical revision)

SEMI E10-92 (technical revision)

SEMI E10-86 (first published)

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