Surface micro-structuring of silica glass by laser-induced backside wet etching using ns-pulsed UV lasers: application into micropatterning of functional materials using self-assembled monolayers

Silica glass is an important material in optics and optoelectronic devices because of its outstanding properties, such as transparence in a wide wavelength range, strong damage resistance for laser irradiation, and high chemical stability. In order to develop simpler processes of micro-fabricating silica glass using a pulsed laser, we have investigated a one-step method to microfabricate a silica glass plate using laser-induced backside wet etching (LIBWE) upon irradiation with ns-pulsed UV lasers. Two laser irradiation systems were employed for the fabrication; (1) mask projection system with a KrF excimer laser and (2) Galvanometer-based point scanning system with a single mode laser beam from a diode-pumped solid state laser at 266 nm. We have succeeded in a fine micro-fabrication of silica glass surface. In addition, a novel approach in the fabrication of microarrays of dye and protein on fused silica plates using LIBWE technique was achieved. The surace of fused silica plates was initially pre-coated using trimethoxysilane self-assembled monolayers (SAMs), then etched using the LIBWE method to obtain the desired microstructures on the plate surface. Using this technique, the SAMs on the non-irradiated areas were able to survive the LIBWE process, and were used as templates for the subsequent deposition of dye molecules, proteins, or polystyrene microbeads via chemical bonding or physical adsorption.