I need some information in mounting a BGA asic, that has been modified. The top is cut-off, modifications to the wirebonds to the die are made. Then it's sealed w/ this black gunk and covered
by this yellowish film. The problem is that this black gunk is melting and shorting out the whole die, when the BGA is being mounted on the PCB.

Is there a different sealant (black gunk) we should be using to close up this BGA? Could it be exceeding the temp. when mounting the BGA? Is there another process we should look at?