Imaging-XPS/Raman investigation on the carbonization of polyimide after irradiation at 308 nm

The laser ablation of polyimide was studied using 308 nm laser irradiation less than or equal to 225 mJ cm(-2). Confocal Raman microscopy revealed the deposition of carbon surrounding the ablation crater, which consists of am orphous carbon with some crystalline features. Inside the crater, graphitic material was detected on top of the cones, very similar to the material fr om cw-Ar+ ion laser irradiation. FT-Raman measurements reveal the presence of intermediates of the polyimide decomposition. Imaging-X-ray photoelectro n spectroscopy confirmed the deposition of carbon material surrounding the ablation crater and showed that the oxygen and nitrogen contents of the rem aining material decrease.