ESD Precautions

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					ESD Precautions
Jeff Bizzell & Tony Weidberg 29/3/04

This note gives a summary of best practice used in the different labs.

The tools for ESD precautions are
    Grounded wristbands Wrist straps should be connected via a constant monitor as
       we have found that new straps do not always give a continuous reading on some
       people and can be subjective to how tight the strap is wrapped onto the wrist . (w)
    Ground mats or ESD safe table surfaces. These should be connected to the local
       ground with a 1 M series resistor (m)
    ESD safe (ie static dissipative) floor and shoes. Cleanroom shoes or boots, that
       are non ESD, should have a strap connecting inside the operator's shoes/socks to
       the outside of the cleanroom shoe as these shoes are mostly insulative (f&s).
    Pin to ground the spine (p).
    Transport of modules: These should be moved enclosed within an ESD bag or
       module box that is place onto the ESD mat with the module removed only after
       the operator has applied a wrist strap. This wrist strap should be connected via a
       constant monitor as we have found that new straps do not always give a
       continuous reading on some people and can be subjective to how tight the strap is
       wrapped onto the wrist. (b)

The best ESD precaution would be:
     to have (f&s) to eliminate risks in carrying modules around.
     (w) should always be used when handling a hybrid or a complete module. (w)
       should also be used when plugging connectors into hybrids or modules.
     The module should be grounded during wire bonding, using eg (p) and the
       operator should use (w) (this was not done in the start-up at Taiwan and caused a
       very high rate of ESD problems),
     Hybrids/modules in a Valencia box should be placed on (m).
     Use (b) for transporting hybrids/modules.

I would like to see all labs using these full ESD precautions. If someone does not want to
do this they should not argue with me but invite a ESD expert to verify that their ESD
precautions are sufficiently safe. Please can all labs keep records of all suspected chip
deaths due to ESD and send me dead chips for inspection.

				
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