Message :  I have a problem on solder joint reliability. It was detected
that some of the solder joint was having minute solder crack on the DIP IC
joints. I believe some might call it solder creep. The crack is so severe
that it cause 'open' joint. It only happened after many temperature cycle
or the board was on the field for more than 6 months. The board is a
through-hole single sided board,substrate is FR1. Apart from the IC joints,
we also detect similar problems on other joints. The crack is only visible
with close inspection, the crack seems to separate the fillet away from the
pad. The board goes through wave soldering once, and no touch up on the
joints. Initially we though it could be due to crack in the thickened
intermetallic layer. But, as know we suspect it could be due to creep on
the solder itself. WE are using eutectic solder composition, and would not
likely to change to other type of solder composition and substrate
materials due to cost impact. I hope someone with similar problem can
enlighten us on any possible solution.

Thank you

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