Hydrodynamic model for UV laser ablation of polymers

The applicability of hydrodynamic models for theoretical description of UV laser ablation of polymers is studied. The plume formation is considered as a first-kind phase transition. In case of strongly absorbing polymers this phase transition occurs as a surface evaporation, and in case of weakly ab sorbing polymers as a bulk evaporation. The vapor plume is assumed to be tr ansparent for laser radiation, and its expansion is described by the isoent ropic hydrodynamic equations. New analytical expressions for ablation (etch ) depths per pulse are obtained, which are in good agreement with the avail able experimental data (Afanasiev et al. 1997).