SEMICONDUCTOR PRESSURE SENSOR AND PRESSURE SENSING DEVICE

摘要

A pressure sensor produced by etching a sacrificial layer. The sensor has an etching channel sealing structure which is excellent in water nonpermeability and the diaphragm of which hardly changes with time. The sensor is excellent in productivity and durability. A very small cavity is made by etching a sacrificial layer, and then a silicon oxide layer is deposited by, e.g., CVD to seal an etching channel. A water-nonpermeable thin film of polysilicon is formed covering the silicon oxide layer. The etching channel sealing structure of the pressure sensor is simplified, water is prevented from entering the cavity to enhance the moisture resistance. The change in shape with time of the diaphragm is suppressed because the sealing material has a small film stress.