Physical quantity sensor and method of making the same

A physical quantity sensor comprising:

• an electroconductive first base member;
• an electroconductive second base member;
• an electroconductive functional member including:
• a movable portion disposed between the first base member and the second base member;
• and
• a frame portion surrounding the movable portion;
• a detection portion configured to detect displacement of the movable portion;
• a first insulation layer bonding the frame portion and the first base member to each other;
• a first metal layer formed on a facing surface of the functional member facing the second base member, the first metal layer including
• a first sealing layer formed on the facing surface of the frame portion and having a frame-like shape, and
• a first contact layer separated from the first sealing layer, extending through the functional member and the first insulation layer, and electrically connected to the frame portion and the first base member;
• a second insulation layer formed on a facing surface of the second base member facing the functional member;
• and
• a second metal layer formed on a surface of the second insulation layer, the second metal layer including
• a second sealing layer formed at a position at which the second sealing layer faces the first sealing layer, and
• a second contact layer separated from the second sealing layer, extending through the second insulation layer, and electrically connected to the second base member,
• wherein a gap between the frame portion and the second base member is sealed by eutectically bonding the first sealing layer and the second sealing layer to each other, and
• wherein the first contact layer and the second contact layer, respectively separated from the first sealing layer and the second sealing layer, are electrically connected to each other, and thereby the first base member, the second base member, and the frame portion are made to have the same potential.