Microscopic model for the ablative photodecomposition of polymers by far-ultraviolet radiation (193 nm)

Short pulses of far-ultraviolet (193 nm) laser radiation are capable of etching organic polymer films without melting the remaining sample. The mechanism proposed for this ablative photodecomposition attributes ablation to the increase in volume that accompanies the photolysis of the polymer. A model of the microscopic process is presented here. The predictions of the model include ablation without melting, a mean perpendicular ejection velocity of 1300 m/s, and an angular distribution of the ablated material which has a narrow peak normal to the surface.