The improvement of electrochemical etching process for silicon microchannel plates

Silicon microchannel plates have been explored intensively for numerous applications especially for ultraviolet image detection. The electrochemical etching in hydrofluoric acid-based solutions is known as a technique for porous silicon formation. The function of backside illumination and temperature in the electrochemical etching of large-size and high aspect ratio silicon microchannels plates has been reported in this paper. The backside illumination was provided by a set of triple 150 W tungsten-halogen lamps with a feedback-loop which keeps the constant current density. And a circulation system was set up to maintain the etching temperature. It was found that proper backside illumination and lower temperature can form an improved etching condition in which etching may result in smoother undercut and better surface topography for large-size silicon microchannel plates.