Patent ID: 8106471

Claim:
A semiconductor dynamic quantity sensor comprising: a sensor part having a support board and a sensor structure arranged on the support board, the sensor structure including a movable part having a movable electrode and a fixed part having a fixed electrode so as to detect a dynamic quantity based on a capacitance of a capacitor defined between the movable electrode and the fixed electrode; and a cap connected to the sensor part so as to cover the sensor structure between the cap and the support board, wherein the movable part has a float portion separated from the support board to define a predetermined interval between the float portion and the support board, at least one of the cap and the support board has a displacing portion displacing the float portion in a direction perpendicular to the support board so as to change the predetermined interval before the dynamic quantity is applied, the movable electrode has a displacement in the perpendicular direction relative to the fixed electrode in accordance with the displaced float portion, so as to decrease an overlap area between the movable electrode and the fixed electrode before the dynamic quantity is applied, the sensor structure detects the dynamic quantity applied in the perpendicular direction based on a change of the overlap area, when the dynamic quantity is applied to the movable electrode in the perpendicular direction, and the sensor structure detects the dynamic quantity applied in a plane direction of the support board based on a separation distance between the movable electrode and the fixed electrode, when the dynamic quantity is applied to the movable electrode in the plane direction.