Hi leohart,
generally, if you have a robust bond stack, it shoud be sufficient to use just one metal to connect the pad. For supply pads, the topmost (usually the thickest) metal should be used. On another note: in some processes it is advisable not to use a minimum width metal trace to connect probepads (or analysis- pads, whatever you call them), but to use a tapered construction or just a wider trace. Sometimes when placing a needle on a probepad, a minimum wire may just tear off as the probepad will be slightly deformed by the force of the needle. We have also seen probepads to slide away and eventually even "lift off" the IMD. So for a robust probepad design, use two layers of metal and connect them with a via array. In this case, even a minimum trace will be sufficient to connect the pad.
Regards,
C