Inertial sensor, method for manufacturing inertial sensor, inertial measurement unit, portable electronic apparatus, electronic apparatus, and vehicle

An angular velocity sensor comprising:

• three directions orthogonal to each other being defined as an X direction, a Y direction, and a Z direction;
• a substrate;
• a fixed detection electrode disposed above the substrate;
• and
• a sensor structure having:
• a mass being movable along the Y direction;
• a first fixed member fixed to the substrate;
• fixed drive electrodes fixed to the substrate;
• a movable drive electrode connected to the mass and arranged between the fixed drive electrodes in the Y direction;
• a movable detection electrode that is substantially plate-shaped on a plane along the X direction and the Y direction and that is connected to the mass, the movable detection electrode facing the fixed detection electrode along the Z direction;
• a first elastic member connecting the mass and the first fixed member, the first elastic member being configured with:
• a first beam and a second beam extending along the X direction and being parallel to each other along the Y direction, the first beam having a first surface along a plane along the X direction and the Y direction;
• a joint connecting the first beam and the second beam, the joint extending along the Y direction;
• a groove provided in the first surface of the first beam and provided as a recessed structure with a closed bottom and opening at the first surface, the groove extending along the X direction;
• and
• two sidewalls provide on both sides of the groove along the Y direction,
• wherein a width along the Y direction of the groove is larger than a width along the Y direction of each of the two sidewalls.