Laser-induced front side etching of fused silica with KrF excimer laser using thin chromium layers

摘要

Laser-induced front side etching (LIFE) is a method for laser etching of transparent materials using thin absorber layers. This approach is a straightforward advancement of the back side etching techniques. Within this study the etching of fused silica with thin chromium layers as radiation absorbers is presented using nanosecond KrF excimer laser with a wavelength of 248 nm. The laser fluence up to 10 J/cm~2, the number of pulses up to 10 as well as the layer thickness from 2 to 250 nm is varied. The treated fused silica was analysed with microscopic (white light interferometry, WLL scanning electron microscopy, SEM) and spectroscopic methods (energy-dispersive X-ray spectroscopy (EDX)).The LIFE method allows the nm-precision etching (rms ≤ 8 nm) of fused silica at moderate laser fluences (2-6 J/cm~2).