Questions And Answers

From ANSI/ESD-S20.20-1999, general guidelines are given for necessary insulators: 6.2.3. Protected Areas6.2.3.1. Protected Areas Requirement Handling of ESDS parts, assemblies and equipment without ESD protective covering or packaging shall be performed in a Protected Area. Caution signs indicating the existence of the Protected Area shall 4 The color of third wire equipment ground can vary with local, national or international electric codes be posted and clearly visible to personnel prior to entry to the Protected Area. ESDS items shall be packaged in ESD protective packaging while not in a Protected Area. Access to the Protected Area shall be limited to personnel who have completed appropriate ESD training. Trained personnel shall escort untrained individuals while in a Protected Area. All nonessential insulators, such as those made of plastics and paper (e.g. coffee cups, food wrappers and personal items) must be removed from the workstation. Ionization or other charge mitigating techniques shall be used at the workstation to neutralize electrostatic fields on all process essential insulators (e.g. ESDS device parts, device carriers and specialized tools) if the electrostatic field is considered a threat.

6.2.3.2. Protected Areas Guidance A Protected Area may be a single workstation (fixed or portable), laboratory, room, building or any other area with pre-designated boundaries that contains materials and equipment designed to limit electrostatic potentials. Humidity control may be a key element in an ESD control program. Propensity for charge generation and accumulation increases with a reduction in humidity. All process essential insulators that have electrostatic fields that exceed 2,000 volts should be kept at a minimum distance of 12 inches from ESDS items. 2,000 volts is a measure of the electrostatic field at the point of measurement and is not necessarily directly related to the electrical potential of the item. The accurate measurement of electrostatic fields requires that the person making the measurement is familiar with the operation of the measuring equipment. Most hand held meters require that the reading be taken at a fixed distance from the object. Equipment manufacturers typically specify that the object being measured needs to have certain minimum dimensions. Objects smaller than the minimum dimensions may not provide an accurate reading. Additional guidance related to Protected Areas may be obtained in ESD ADV 2.0