Silicon (12) is etched through a mask (11) comprising a layer of organic resin material (such as novolac) through which openings (32) 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 (32) are then formed by depositing droplets of a caustic etchant such as sodium hydroxide (NaOH) or potassium hydroxide (KOH) 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 (HF) and potassium permanganate (KMnO.sub.4) to the exposed surface through the openings in the mask to etch the silicon to a desired depth (83).