1 This technical specification is intended to cover the protection from ESD damage of all electronic devices with voltage sensitivity of not lower than 100 V through their entire life. This is from the commencement of manufacture, through product assembly, product use and possible repair until the end of the product life.
This technical specification is intended to cater for electronic components, assemblies and subassemblies with a sensitivity of 100 V or greater (human body model (HBM)), and as such covers most items available. There are on the market a few items which may suffer damage at lower levels. Where these are used, additional or alternative methods should be used. These are not covered by either IEC 61340-5-1 or this user guide, as it would not be reasonable or economic to equip the general EPA to cater for these. Additional information on these may be found in many of the references in the bibliography.
The HBM has been chosen as the major criteria, as damage from human contact is still the most common source even in today's automated society. There are several values given in different sources for HBM, but the chosen one is 100 pF and 1 500 Ω.
2 Low humidity
At low relative humidities the dissipation of static charges often becomes more difficult, and some materials may not work efficiently. Above about 20 % relative humidity most materials maintain most of their efficiency. Where relative humidity may go lower the user should pay particular attention that the materials selected will perform effectively at the minimum expected relative humidity. This is of particular importance in very cold and non-oceanic climates.
3 Clean rooms
For clean rooms, the specialist areas are considered to be class 100 or tighter. Many of the techniques in current use for ESD protection will not satisfy the clean room constraints, for example, carbon breaking down, ionics from spray or particles from ionizer needles. Some alternative materials are available, with improved ones still being developed, that will cope with both conditions and these should be used. This area is particularly important as clean operation is an essential part of semiconductor manufacture. Damage occurring at this stage may result in undetected "walking wounded" devices which can have very expensive results. The clean room application is currently the most difficult to control, particularly in class 10 and class 1 rooms. IEC 61340-5-1 embodies current technology. As new and improved materials and techniques become available this area will be improved, with benefits in reliability.
IEC TS 61340-5-2:1999 history
1999IEC TS 61340-5-2:1999 Electrostatics - Part 5-2: Protection of electronic devices from electrostatic phenomena - User guide