Inertial sensor, method for manufacturing inertial sensor, and inertial measurement unit

An inertial sensor comprising:

• three mutually orthogonal axes being defined as an X-axis, a Y-axis, and a Z-axis, a direction parallel to the X-axis being defined as an X-axis direction, a direction parallel to the Y-axis being defined as a Y-axis direction, and a direction parallel to the Z-axis being defined as a Z-axis direction;
• a base substrate made of a silicon material including a first upper surface and a first lower surface that are outwardly opposite to each other and extend perpendicular to the Z-axis, and a first recess provided on the first upper surface;
• a buried insulation layer formed on an outer edge of the first upper surface of the base substrate and surrounding the first recess;
• a semiconductor layer arranged so as to overlap an uppermost surface of the buried insulation layer and the first recess in a plan view from the Z-axis direction;
• and
• a lid body made of the silicon material including a second upper surface and a second lower surface that are outwardly opposite to each other and extend perpendicular to the Z-axis, and a second recess is provided on the second lower surface, the second recess facing the semiconductor layer,
• wherein the semiconductor layer has a capacitance element formed in a central area thereof, and the capacitance element faces the first recess and the second recess,
• an insulation layer is in a frame shape and is formed on an outer peripheral edge of the semiconductor layer, and the insulation layer faces the lid body,
• the insulation layer and an outer edge of the lid body surrounding the second recess are bonded with an adhesive layer,
• a groove is formed on the outer edge of the lid body and connects a cavity inside the second recess to an outside of the lid body prior to sealing,
• a hole is formed in the groove that opens to the outside of the lid body and connects the cavity to the outside by the adhesive layer and the insulation layer prior to sealing,
• a sealer that seals the hole and is formed by melting a processed portion of the lid body, and
• the sealer includes the silicon material of the lid body mixed with a material of the adhesive layer.