Decapsulating ICs used to be an exotic technique. (I should know, I did that professionally for one of the big IC vendors back in the 1980s.) These days, more and more people are learning to take apart ICs for a variety of reasons. If you are interested in doing it yourself, [Juan Carlos Jimenez] has a post you should read about using acid to remove epoxy from ICs.
[Juan Carlos] used several different techniques with varying degrees of success. Keep in mind, that using nitric acid is generally pretty nasty. You need safety equipment and be sure to plan for bad things to happen. Have eyewash ready because once you splash acid in your eye, it is too late to get that together.