Pressure sensor structure, pressure sensor device, and method of manufacturing pressure sensor structure

A pressure sensor device comprising:

• a pressure sensor structure to detect a change in interelectrode electrostatic capacitance;
• an integrated circuit to process a signal from the pressure sensor structure;
• a circuit substrate on which the integrated circuit and the pressure sensor structure are mounted;
• and
• a case made of metal or a synthetic resin to accommodate the integrated circuit and the pressure sensor structure together with the circuit substrate;
• wherein
• the pressure sensor structure includes:
• a sensor body including:
• a diaphragm plate that functions as a sense electrode;
• a base electrode that faces the diaphragm plate;
• and
• a sidewall layer to maintain a gap between the diaphragm plate and the base electrode;
• and
• a conductive guard substrate to support the sensor body;
• wherein
• the sidewall layer includes a guard electrode layer and upper and lower guard electrode insulating layers to electrically insulate the guard electrode layer;
• the guard substrate is electrically connected to the guard electrode layer to function as a guard electrode together with the guard electrode layer;
• an electrically insulating layer to electrically insulate the guard substrate is between the guard substrate and the sensor body;
• and
• between the electrically insulating layer and the sensor body, a second base electrode and a second guard electrode layer are provided in a same layer and electrically isolated from each other.