Fabrication of micro-texture channel on glass by laser-induced plasma-assisted ablation and chemical corrosion for microfluidic devices

Abstract

A process combined laser-induced plasma-assisted ablation (LIPAA) with chemical corrosion is proposed to fabricate micro-channels with micro-texture surface on glass. Micro-cracks form under the recast layer of glass due to the thermal expansion and contraction strain induced by the plasma during LIPAA. This “defect”, micro-cracks, can be further developed into tree-like micro-textures as the recast layer is removed by chemical corrosion. The effects of chemical corrosion, including corrosive time and corrosive concentration, on the micromorphology of surface texture were investigated. Several representative textures on channel surface were obtained. In order to fabricate micro-channels with micro-texture surface, the effecting factors of LIPAA, including number of scanning cycles, scanning speed, pulse power density and gap distance between glass and sacrificial material, on the channel geometry and chemical corrosive rate were also investigated. The results show that the gap distance is the most significant influence factor on the channel width before chemical corrosion. The corrosive rate of channel width increases with power density and decreases with gap distance. The channel depth before corrosion and its corrosive rate increase with power density and decrease with scanning speed and gap distance. The corrosive rate of width and depth increases with number of scanning cycles till 150, and then reaches steady. The micro-channel with micro-texture surface fabricated by LIPAA and chemical corrosion can be potentially applied in some microfluidic devices.