SEMI F49 - Guide for Semiconductor Factory Systems Voltage Sag Immunity

Volume(s): Facilities
Language: English
Type: Single Standards Download (.pdf)

This Standard was technically approved by the Facilities Global Technical Committee. This edition was approved for publication by the global Audits and Reviews Subcommittee on August 22, 2013. Available at and in December 2013; originally published February 2000; previously published November 2008.


NOTICE: This Document was reapproved with minor editorial changes.


A guide defining a systems approach to power conditioning is needed for semiconductor and flat panel display (FPD) facilities. Semiconductor and FPD factories require high levels of power quality due to the sensitivity of equipment and process controls. Semiconductor and FPD processing equipment is especially vulnerable to voltage sags. The facility electrical system distributes power to process equipment, support equipment, and facility infrastructure equipment. Facility electrical distribution systems should be designed to integrate the voltage sag susceptibility of all the equipment with the power quality supplied by the utility. Installing effective and efficient facilities power conditioning requires identification of appropriate conditioning technologies and properly applying the conditioning equipment.


Utilizing recommendations in this guide should result in effective power conditioning of the facility electrical distribution system such that the process equipment, associated support equipment and facilities infrastructure equipment function within acceptable ranges.


This Guide is intended for facilities engineers, equipment engineers, and facilities managers who specify compatibility requirements for equipment and utility services, and in particular for electrical power requirements such as those found in SEMI E51.


This Document provides recommendations for implementing a systems approach to identification and resolution of voltage sag events that disturb the performance of semiconductor process equipment. A program recommending facilities electrical distribution system monitoring and control strategies for both the direct and indirect effect of voltage sags on wafer processing is outlined as follows:

  • Reasons for monitoring and conditioning (see ¶ 7.1).

  • Facilities electrical distribution system power monitoring and conditioning (see ¶ 7.2).

  • Quantifying process equipment performance (see ¶ 7.3).

  • Quantifying support equipment and facilities infrastructure equipment performance (see ¶ 7.4).

  • Utility power monitoring strategies (see ¶ 7.5).

  • Measurement and modeling strategies (see ¶ 7.6).

  • Power enhancing and conditioning strategies for use in the facilities electrical distribution system (see ¶ 7.7).


Referenced SEMI Standards

SEMI E51 — Guide for Typical Facilities Services and Termination Matrix
SEMI S2 — Environmental, Health, and Safety Guideline for Semiconductor Manufacturing Equipment

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