Hitachi, Ltd.

Takashi Shiota

Noriyuki Sakuma

Atsushi Isobe

Yuudai Kamada

Chisaki Takubo

Hiroyuki Uchiyama

Takashi Oshima

Tatsuyuki Saito

Tatemi Ido

Yuki Furubayashi

Provided are acceleration sensor, geophone and seismic prospecting system with high sensitivity and low power consumption. The acceleration sensor includes a mass body displaceable with respect to a rotation shaft. The acceleration sensor includes a first AC servo control facing a first symmetrical region of the first movable portion, a second AC servo control electrode facing a second symmetrical region of the second movable portion, and a DC servo control electrode facing an asymmetrical region of the second movable portion. A first AC servo capacitive element is formed by the first movable portion and the first AC servo control electrode, a second AC servo capacitive element is formed by the second movable portion and the second AC servo control electrode, and a DC servo capacitive element is formed by the second movable portion and the DC servo control electrode.

Acceleration sensor, geophone, and seismic prospecting system

An acceleration sensor has high sensitivity, low power consumption and high linearity of output to the applied acceleration under gravity. To solve the above problem, the acceleration sensor is provided with a movable section placed between a base substrate and a cap substrate and rotating about a rotation axis. A top left electrode included in the cap substrate and a left movable electrode included in the movable section form a left capacitor, and a top right electrode included in the cap substrate and a right movable electrode included in the movable section form a right capacitor. Then, a lateral width of a first detection region in which capacitance is detected between the top left electrode and the left movable electrode, and a lateral width of a second detection region in which capacitance is detected between the top right electrode and the right movable electrode are different from each other.

Acceleration sensor

There is provided an acceleration sensor with low noise and high sensitivity. Specifically, a first number of opening portions are formed in a region corresponding to a heavyweight section of a mass body, on a surface of a membrane layer, and a second number of opening portions are formed in a region corresponding to the heavyweight section of the mass body, on a back surface of the membrane layer. The opening portion and the opening portion are connected to each other to form a plurality of through portions on the membrane layer, and the first number is larger than the second number.

An acceleration sensor () includes a fixed portion (), a movable portion () connected to the fixed portion (), a lower electrode () that is disposed to face a lower surface of the movable portion (), and an upper electrode () that is disposed to face an upper surface of the movable portion (). A distance in an x-axis direction between an end portion () of the lower electrode () and the fixed portion () is shorter than a distance in the x-axis direction between an end portion () of the upper electrode () and the fixed portion (). Further, a distance in the x-axis direction between an end portion () of the lower electrode () and the fixed portion () is shorter than a distance in the x-axis direction between an end portion () of the upper electrode () and the fixed portion ().

There is provided an inertia sensor with low noise and high sensitivity. The inertia sensor captures a physical quantity as a change of electrostatic capacitance and detects the physical quantity based on a servo voltage generating electrostatic force that cancels the change of the electrostatic capacitance. The inertia sensor includes a detection capacitor unit that captures the physical quantity as the change of the electrostatic capacitance and a servo capacitor unit to which the servo voltage is applied. Here, the detection capacitor unit and the servo capacitor unit are connected mechanically through an insulation material.

Inertia sensor with improved detection sensitivity using servo voltage to detect a physical quantity

Airtightness in a cavity of an inertial sensor (acceleration sensor) is increased to achieve high sensitivity. In the acceleration sensor having movable electrodes VE, VEand fixed electrodes FE, FE, the fixed electrodes are formed by portions surrounded by a through hole THprovided in a cap layer CL, and the through hole is filled with an insulating film IFand polysilicon P and has a wide portion (WP). The wide portion has a gap SP that is not filled with the insulating film IFand the polysilicon P, and the gap SP is filled with the interlayer insulating film ID. With such a configuration, degassing can be exhausted through the gap (airway) SP in a pressure reducing step.

Inertia sensor and method of manufacturing the same

A method manufactures a semiconductor device by forming at least an active device on a principal surface of a semiconductor substrate; etching the semiconductor substrate to thereby form a viahole adjacent to an active region where the active device is formed; and forming a plated wiring including the inner wall of the viahole and extending to an electrode of the active device on the surface of the substrate. This method uses a photo sensitive polyimide material as an etching mask in the step of forming a viahole and can thereby form a fine viahole in a high yield.

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Tokyo, Japan

Takashi Shiota