Dear colleagues, I open oxide on silicon to form contact holes, sputter 100% Aluminum, then pattern the Aluminum, followed by a form gas anneal (FGA). Then, at the end of the process, the wafers are diced and after dicing my Aluminum pads turn 'black'. Not all of them and the 'black' is all from slightly darker to completely black. Has anyone of ever seen something like that before? Thanks and best regards, Stefan