Fabrication of metallic micro channels of high aspect ratio using laser-assisted thermochemical wet etching

Abstract

Characteristics of laser-assisted wet etching of titanium in phosphoric acid were investigated to examine the feasibility of this method for fabrication of high-aspect-ratio microchannels. Laser power, number of scans, etchant concentration were chosen as the major process parameters influencing on the cross sectional profile and aspect ratio of an etched channel. Experimental results showed that laser beam power influences on both etch width and depth while number of scans mainly affects on the etch depth. At low etchant concentration, the cross sectional profile of an etched channel is close to a U-shape but it gradually turns into a V-shape as the concentration increases. On the other hand, the surface of etched channels showed a smoother morphology at a higher concentration. It is demonstrated that high-aspect-ratio metallic microchannels with different cross sectional profiles can be fabricated by properly controlling the process parameters. Microchannels of an aspect ratio close to 10 were fabricated.Characteristics of laser-assisted wet etching of titanium in phosphoric acid were investigated to examine the feasibility of this method for fabrication of high-aspect-ratio microchannels. Laser power, number of scans, etchant concentration were chosen as the major process parameters influencing on the cross sectional profile and aspect ratio of an etched channel. Experimental results showed that laser beam power influences on both etch width and depth while number of scans mainly affects on the etch depth. At low etchant concentration, the cross sectional profile of an etched channel is close to a U-shape but it gradually turns into a V-shape as the concentration increases. On the other hand, the surface of etched channels showed a smoother morphology at a higher concentration. It is demonstrated that high-aspect-ratio metallic microchannels with different cross sectional profiles can be fabricated by properly controlling the process parameters. Microchannels of an aspect ratio close to 10 were fabricated.