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ESD Awareness: Search 3

1. What is the main source of ESD in a manual assembly process?
   
   ESD from charged people.
   
   
2. What percentage of ESD damaged components has been estimated to pass tests, to be found by customers later?
   
   90%
   
   (There may be variability on this figure from different sources)
   
   
3. What percentage of EOS/ESD damaged components have been found to be damaged by non-grounded people?
   
   Namaguchi & Uchida found that 60–90% of defective or non-conforming devices were damaged by EOS or ESD. About 70% were found to be damaged by non-grounded people.
   
   (There may be wide variability on this figure from other sources. The key point is that the non-grounded human body is a major ESD source)
   
   
4. What is the approximate voltage threshold, below which a person will not feel an ESD?
   
   About 3,000–4,000V
   
   (There may be variability on this figure from different sources. The threshold is highly variable in practice.)
   
   
5. What is the target ESD withstand voltage of many integrated circuits that have on-chip protection circuits?
   
   2,000V
   
   Note that this figure is well below the threshold of a person feeling a shock from an ESD event.
   
   
6. Give four types of component that may have ESD withstand voltage less than 2,000V.
   
   • MR heads
     
   • RF MOSFETS
     
   • Power MOSFETS
     
   • VLSI
     
   • HCMOS
     
   • Linear MOS
     
   • Small geometry bipolar
     
   • Film resistors.

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