Can you define your reflow and cleaning processes and materials used. There
may be some relevance and this will help dimension the problem. Also please
clarify [as it is not clear from your posting] if you have done any leak tests
after reflow but before cleaning. It is entirely possible that the lids are
shifting then and rhe cleaning process is simply injecting liquid rather than
causing the leak.



-----------------------
     We are seeing problems with water getting into our hybrid ICs during
aqueous cleaning.  The substrate is made of alumina as well as the lid.
The substrate is 1.5 in. square.  The lid is 1.45 in square with a wall
thickness of .050 in and height of .105 in. At first we used Kyocera NC0150
B stage epoxy to attach the lid to the substrate.  What we found was cracks
in the epoxy.  We then tried RJR poly RJ4B, but failed because of leakage
problems during the leakage test (submerge the part in a liquid and look
for gas bubbles). We then tried RJ9F epoxy which started to have fine gas
bubbles all around the seal after 30 seconds...........................

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