Single pulse threshold and transmission behaviour of a triazeno-polymer during pulsed UV-laser irradiation

The threshold fluence F-Th Of a triazeno-polymer was measured in the low fluence range for thin films using conventional UV-spectroscopy. It was found that there is a clearly defined F-Th for 308 nm irradiation between 20 and 25 mJ cm(-2). In the case of 248 nm irradiation, a 'threshold fluence range' between 16 and 32 mJ cm(-2) was determined. Additional transmission measurements have been performed showing that the target transmission at 248 nm increases only slightly, whereas for 308 nm the transmission increases by a factor of approximate to 4. This result shows that dynamic target absorption properties are very important for describing the ablation process.