Hello all,

I have a case that recently came up questioning possible gold
embrittlement in solder joints.  I was wondering if I could bounce a few

numbers off this forum and see what all of you think.  Any help or
reference material
would be great.

Ceramic 4 lead oscillator.
CuNiAu lead finish.
Component gold plating thickness specs are 12 to 40 microINCHES of gold.
(I realize that this is quite high)
Calculations indicate varying % gold by volume of solder to be between
1.36% and
2.28%, all the way up to possibly as high as 3.13%
Do you know what the acceptable gold volumes are and the impact to long
term reliability?

Increasing the volume deposited might only make the solder wick up
further along the lead, pulling more gold into the joint.  This probably
wouldn't really help in this particular case.
Would increasing the pad size AND solder volume (hence trying to
minimize forcing solder up the lead but rather keeping it flat on a
larger surface) help?  Would the gold spread evenly to the entire solder
volume or still concentrate near the lead?

Any help or reference material would be great!
Regards,
--
Jason Cross
Physical Technology Engineer
Alcatel Canada, Inc.
(613) 784-4793
(888) 662-3425 x 4793

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