We're being asked to perform  electro migration testing on an ongoing
basis on pcbs we produce. The test required is defined as follows:
A drop of water (.5 Megohms/cm.) is dropped between 2 traces spaced .010
apart and a current of 3V DC is applied. Current leakage of no more than
30 micro amps / thou of seperation /minute must be met ???

*Are you being asked to do this on an actual board, loaded with components,
or on a test coupon processed along with the board, or on a bare PWB?

 Is this a "standard" test and if so is a procedure defined anywhere (
IPC , MIL. etc) ?

*Depends on what you consider as a standard test.  I have seen this test
used at a couple of manufacturers as a QC check on incoming boards.  Each
has a slightly different voltage and current requirement.  Most of these
tests grew out of the ASTM method for comparative tracking index (CTI) done
on laminate.  The theory is that if you have contaminants on the board,
they will leach out into the DI water, creating an electrolytic solution.
The dirtier the board, the more conductive the electrolyte.

Is it typical to perform this as a routine QC check
or is it the type of test normally performed as a qualification  test
only ?

*A few companies do, but it is not an accepted standard.

Doug Pauls
Rockwell Collins

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