Technetters,

We are experiencing what appears to be the result of some type of
outgassing of white legend ink.  
Details: Board design uses a white legend ink as an overcoat.
Subsequent processing includes die attach (COB) using electrically
conductive epoxy.  Testing shows that the die attach epoxy strength (die
shear) is greatly reduced on boards that use the white legend ink. I do
not believe this to be a surface contaminant issue since the epoxy
failure mode is cohesive.  Epoxy cure temperature is 150C in a air
circulating oven with a high exhaust rate.   Questions - Is outgassing
of legend inks and LPI's a probable cause?   Is any information
available regarding this ?

Bill C.

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