silicon is etched through a mask comprising a layer of organic resin material through which openings are formed in the areas to be etched . the layer of organic resin is first deposited over a free surface of the device to be etched . the openings are then formed by depositing droplets of a caustic etchant such as sodium hydroxide or potassium hydroxide with an inkjet printer . the etchant reacts with the resin to expose the silicon surface in areas to be etched . the etching of the silicon surface is performed by applying a dilute solution of hydrofluoric acid and potassium permanganate to the exposed surface through the openings in the mask to etch the silicon to a desired depth .