Cool. Surgeries are done on internal battery backed up Dallas RAMS too to access the pins for the battery, The new battery is placed on top.

If you have the map where to remove the Epoxy, You stand a good chance of repair.

Desoldering the chip (heating it) might destroy it's contents.

FYI and ASIDE: Had an ultrasonic bonder at work to play with, but it did not work well.