Direct photoetching of polymer films using vacuum ultraviolet radiation generated by high-order anti-Stokes Raman scattering

Abstract
High‐order anti‐Stokes Raman pulses of the vacuum ultraviolet were successfully utilized for ablation of polymer films. Efficient anti‐Stokes conversion of the fourth harmonics of a conventional Nd:YAG laser provided fluences as large as 0.4 J/cm2 for a sixth‐order anti‐Stokes pulse at 160 nm. The selection of irradiation wavelength by a ready choice of scattered orders of Raman waves could verify critical wavelength dependence of ablation effect, which turned out that only the light at 160 nm made it possible to ablate polytetrafluoroethylene (PTFE) film with such low fluences.