MANUFACTURE OF PRESSURE RECEIVING DIAPHRAGM IN SEMICONDUCTOR PRESSURE SENSOR

摘要

PURPOSE:To improve yield by forming the pattern of a pressure receiving diaphragm by photolithography, and etching an SiN film, and performing electrochemical etching, and then etching the SiO2 film at the end face of a boss part with the SiN film at the end face of a foot as a mask. CONSTITUTION:Al or Au is vapor deposited on the entire surfaces of the wirings from a diffusion resistance 13 and a diffusion terminal 14 so as to form electrodes 17 and 18. The electrode 18 is connected to the + pole of a constant currents source in an electrochemical etching vessel so as to form an anisotropic etching groove 21 in a substrate by electrochemical etching. Accordingly, at the substrate 10 are formed a boss part 19 (having an SiO2 film 12 at the end face) and a foot 20 (having an SiO2 film 12 and an SiN film 15 at the end face), By 10% HF solution or buffered hydrofluoric acid solution, the SiO2 film 12 at the end face of the boss part 19 is removed, with the SiN film 15 at the end face of the foot 20 as a mask, by etching. With KOH solution as etchant, electrochemical etching is done so as to form the boss part 19 into the specified form (specified, gap l is made to the end face of the foot 20).