Surface micro-fabrication of silica glass by excimer laser irradiation of organic solvent

Laser-induced backside wet etching (LIBWE) of silica glass plates was performed by the excitation of a pure toluene solution with an ns-pulsed KrF excimer laser at 248 nm. Well-defined grid micro-pattern was fabricated without debris and micro-crack around the etched area. The etch rate, which increased linearly with laser fluence, was 30% higher than that in the case of acetone solution of pyrene dye at a concentration of 0.4 mol dm−3. To understand the etching mechanism, the formation and propagation of shock wave and bubble were monitored by time-resolved optical microscopy at the interface between the silica glass and the toluene solution during etching process. Transient high pressure as well as high temperature generated by UV laser irradiation plays a key role in the etching process.