Hi All,

Another question for who can ever answer it.

What factors affect the dissolution of plated copper into solder during the
soldering process?  Lets ignore the soldering parameters (temperature,
composition, wave/pot turbulence....) and focus on the copper plating.

We have PCBs that are seeing a 50% reduction in plated copper thickness
during a standard IPC TM-650 thermal stress.  We've cross-sectioned enough
thermal stressed boards to know that this isn't normal.   Another question.
 We are consistently seeing the reduction on the top side of the board (the
side that doesn't come in direct contact with the molten solder), why the
top side and not the solder side?

The boards are 14 layer with 4 2oz copper power/ground planes.

Thanks

Scott Severson
Benchmark Electronics Inc.

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