Ultra-short pulsed laser ablation of polymers

We report the experimental results of the ablation rate per pulse as a function of the laser fluence and images of the surface morphology, as examined by atomic force microscopy, for a number of organic polymer materials of special interest in microelectronics and biomedical applications. The ablation parameters and the surface modifications are examined under various irradiation conditions using laser wavelengths ranging from the ultraviolet through the visible to the infrared and pulse widths ranging from nanoseconds to femtoseconds. Our results are discussed in the view of interplay between the material properties and the radiation dependent parameters governing the ablation process. Visible and infrared ultra-short pulsed laser ablation of the polymer samples was performed with a very low threshold fluence of approximately 0.2 mJ/mm2. The irradiated polymers exhibit different optical transmission properties in the corresponding spectral regions. The quantitative results on ablation rate versus laser energy fluence show that the picosecond laser ablation is more efficient than the sub-picosecond and nanosecond ablation, i.e., it exhibits higher etch rates before the onset of any saturation.