Photophysical ablation of organic polymers: the influence of stresses

Non-stationary effects and the influence of mechanical stresses during ns and ps UV excimer laser ablation of organic polymers are discussed. Direct comparison of theoretical calculations with experimental data for laser ablation of polyimide at different wavelengths shows that the photophysical ablation model describes the kinetics of ns UV laser ablation reasonably well. Small gaseous fragments produced within the bulk polymer may be responsible for the mass losses observed near the ablation threshold. At higher fluences, stresses caused by these fragments may facilitate photophysical ablation. With ps laser pulses, acoustic waves related to transient thermal stresses lead to additional defect formation.