Fiducial marks are dots etched on board panel for which SMT assembly is required (provide viewing targets for camera to locate correct position). These marks should be in diameter of approx. 0.06″ and free from solder mask. There should be 2 sets of fiducials if fine-pitch components are use. The first set is called the panel mark, one for each panel corners (at lease .5″ from any panel tooling holes). The second set is called the local mark, one for each fine-pitch IC located at the absolute center position of that IC.