In front-end engineering, we must gather as much manufacturing information as possible from the printed circuit board data we receive. This includes customer service notes, customer emails, and the general spec, if available. Usually there is enough information to release a printed circuit board (PCB) package to manufacturing. However, I have found many gray areas that haunt our engineering department.
The reason printed circuit boards (PCBs) require a surface finish rather than being left as simply bare copper is because while copper is an excellent conductor, leaving it exposed will cause it to oxidize and deteriorate over time. The increased exposure will cause the PCB to fail much sooner than expected.