Hi! I had experience with my customer complain about the delamination on BGA.
The first question, I will ask my customer how they removed the parts and de-cap (my customer is using de-cap instead of SEM, I prefer SEM). Most of the customer which I believed that they removed the component from the board directly without baking the whole assembly to remove the moisture on the MSD device.
I am not sure that how long of your board expose to the environment. If you removed the parts stay for a certain period, moisture will trap into the encapsulation. When you de-soldering, it may caused delamination.
If it is a QFP then you can just cut the lead without apply any heat.
Beside the humidity, the other possible is the material itself or your reflow profile.
Good Luck!
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