This Recommended Practice (RP) discusses methods for specifying and evaluating the effectiveness of techniques for controlling electrostatic charge. Proper control of electrostatic charge may reduce particulate contamination on surfaces and the likelihood of electrostatic discharge. This document, which describes typical control systems and their applications, also lists methods of testing and measurement of charge generation, charge neutralization, resistivity of surfaces and materials, and static field attenuation.

BACKGROUND AND PURPOSE

Electrostatic charge and discharge are serious problems in the cleanroom. This RP may be used as a guide in specifying the components of an overall static control system to control and limit the effects of electrostatic charge and discharge. The electrostatic effects that will be considered are:

• attraction of contaminants to charged objects or personnel, and subsequent transfer of these contaminants to critical surfaces,

• damage to a product caused by electrostatic discharge (ESD),

• production equipment malfunctions caused by electrostatic discharge.

The effects of electrostatic charge on particulate contamination have been studied and documented extensively (see Appendix B). Similar studies have investigated the problems caused by electrostatic discharge damage to products. The damaging effects of electrostatic discharge on microprocessor-based production equipment are well-known. While detailed discussion of specific fields of expertise is beyond the scope of this RP, this document sets forth the concepts underlying a systematic approach to the control of problems caused by electrostatic charge.