Etching a Micro-Trench with a Maximum Aspect Ratio of 60 on Silica Glass by Laser-Induced Backside Wet Etching (LIBWE)

We have successfully fabricated a deep micro-trench about 7 µm wide and 420 µm deep on silica glass with a maximum aspect ratio of 60 by laser induced backside wet etching (LIBWE) via KrF laser ablation of a saturated pyrene/acetone solution. The processing time for the microetching was as short as 5 min at a repetition rate of 80 Hz and a fluence of F = 1.0 J·cm -2 ·pulse -1 . The etch rate was calculated to be approximately 17 nm·pulse -1 . The LIBWE method is shown to be very useful for surface microstructuring of silica glass with high aspect ratio and high throughput.