Process for manufacturing a pressure-monitoring device provided with a triaxial piezoresistive accelerometer

摘要

A manufacturing process of a semiconductor pressure-monitoring device (30) is disclosed, envisaging: providing a wafer (31) of semiconductor material; providing, in a first region (34a) of the wafer (31) a first buried cavity (22) and a first membrane (23), suspended over, and closing at the top, the first buried cavity (22); providing, in a second region (34b) of the wafer (31), a second buried cavity (40) and a second membrane (41), suspended over, and closing at the top, the second buried cavity (40); coupling an inertial mass (25) in a rigid way to the first membrane (23), by forming the inertial mass (25) on top of a surface of the first membrane (23) opposite to the first buried cavity (22); providing, in the first membrane (23), first piezoresistive transduction elements (24) sensitive to strains of the first membrane (23) due to movements of the inertial mass (25) in response to a sensed acceleration and generating corresponding electrical signals, so as to provide an acceleration sensor (35); and providing, in the second membrane (41), second piezoresistive transduction elements (42) sensitive to strains of the second membrane (41) in response to a sensed pressure and generating corresponding electrical signals, so as to provide a pressure sensor (36) integrated with the acceleration sensor (35) in the wafer (31). A semiconductor pressure-monitoring device (30) is also disclosed, made with the above manufacturing process.