Abstract: A method for determining a peak fluence of an excimer laser includes scanning an excimer laser beam in a predetermined pattern on a film. The film can include a polymer layer atop a substrate including an upper layer having a first characteristic and a lower layer having a second characteristic detectably distinct from the first characteristic. The predetermined pattern includes a plurality of discrete points receiving incrementally greater numbers of pulses, at least one point receiving a sufficient number of pulses to penetrate through the polymer layer and the upper layer. A breakthrough point is detected at which a smallest number of pulses was sufficient to penetrate through the polymer layer and the upper layer, thereby exposing the lower layer to a detection of the second characteristic. A peak fluence of the excimer laser can then be determined from the number of pulses received at the detected breakthrough point.