The primary purpose of printed circuit board (PCB) reverse engineering is to determine electronic system or subsystem functionality by analyzing how components are interconnected. We performed a series of experiments using both inexpensive home-based solutions and state-of-the-art technologies with a goal of removing exterior coatings and accessing individual PCB layers. This paper presents our results from the most effective techniques.
more here..........https://www.usenix.org/system/files/conference/woot14/woot14-grand.pdf
more here..........https://www.usenix.org/system/files/conference/woot14/woot14-grand.pdf