Panasonic Electric Works Co., Ltd.

Matsushita Electric Works, Ltd.

Kazushi Kataoka

Hisakazu Miyajima

Toru Baba

Yoshiyuki Takegawa

Yuji Suzuki

Kouji Gotou

Takafumi Okudo

Takashi Saijo

Takuya Komoda

Hitoshi Yoshida

Masahiko Suzumura

Daisuke Wakabayashi

Sumio Akai

Koji Goto

Makoto Morii

A wafer level package structure, in which a plurality of compact sensor devices with small variations in sensor characteristics are formed, and a method of producing the same are provided. This package structure has a semiconductor wafer having plural sensor units, and a package wafer bonded to the semiconductor wafer. The semiconductor wafer has a first metal layer formed with respect to each of the sensor units. The package wafer has a bonding metal layer at a position facing the first metal layer. Since a bonding portion between the semiconductor wafer and the package wafer is formed at room temperature by a direct bonding between activated surfaces of the first metal layer and the bonding metal layer, it is possible to prevent that variations in sensor characteristics occur due to residual stress at the bonding portion.

Wafer level package structure and production method therefor

A wafer level package structure with a plurality of compact sensors such as acceleration sensors and gyro sensors is provided. This package structure is composed of a semiconductor wafer with plural sensor units, and a pair of package wafers bonded to both surfaces of the semiconductor wafer. Each of the sensor units has a frame having an opening, a movable portion held in the opening to be movable relative to the frame, and a detecting portion for outputting an electric signal according to a positional displacement of the movable portion. Since the semiconductor wafer is bonded to each of the package wafers by a solid-phase direct bonding without diffusion between a surface-activated region formed on the frame and a surface-activated region formed on the package wafer, it is possible to prevent that variations in sensor characteristics occur due to residual stress at the bonding interface.

Wafer level package structure, and sensor device obtained from the same package structure

A sensor device having small variations in sensor characteristics and improved resistance to electrical noise is provided. This sensor device has a sensor unit, which is provided with a frame having an opening, a movable portion held in the opening to be movable relative to the frame, and a detecting portion for outputting an electric signal according to a positional displacement of the movable portion, and a package substrate made of a semiconductor material, and bonded to a surface of the sensor unit. The package substrate has an electrical insulating film on a surface facing the sensor unit. The package substrate is bonded to the sensor unit by forming a direct bonding between an activated surface of the electrical insulating film and an activated surface of the sensor unit at room temperature.

Sensor device and production method therefor

A compact sensor device having stable sensor characteristics and the production method are provided. The sensor device is formed with a sensor substrate and a pair of package substrates bonded to both surface of the sensor substrate. The sensor substrate has a frame with an opening, a movable portion held in the opening to be movable relative to the frame, and a detecting portion for outputting an electric signal according to a positional displacement of the movable portion. Surface-activated regions are formed on the frame of the sensor substrate and the package substrates by use of an atomic beam, an ion beam or a plasma of an inert gas. By forming a direct bonding between the surface-activated regions of the sensor substrate and each of the package substrates at room temperature, it is possible to avoid inconvenience resulting from residual stress at the bonding portion.

A semiconductor acceleration sensor comprises: a frame having an opening inside thereof; flexible beams extending from the frame to the inside of the opening of the frame; a weight suspended from and supported by the beams so that the weight can freely move; piezoresistors to be mounted on the beams and to vary the resistance values in response to accelerations which work on the piezoresistors. The frame comprises damper plate portions, each of which covers a part of the opening spanning from a corner portion of two neighboring sides of the frame on the side of the opening to the inside of the opening, and each of which serves serve as a stopper to limit movement of the weight. The weight has corner portions which face the corner portions, respectively, and each of which is chamfered to have a shape of arc or a polygonal line consisting of at least three sides as seen in plan view. Thereby, the breaking strength of each stopper is increased, and hence a semiconductor acceleration sensor having superior shock resistance can be obtained.

Semiconductor acceleration sensor and method of manufacturing the same

A method for manufacturing a static induction type semiconductor device is to form gate zones on a surface side of a semiconductor substrate, to cover the surface including the gate zones with an oxide film, to form through the oxide film apertures for providing cathode zones in the substrate, the apertures respectively overlapping partly each gate zone, and to form the cathode zones with thermal diffusion of an impurity carried out through the apertures, the cathode zones thus partly overlapping the gate zones. Concentration of the impurity as well as the depth of the diffusion at thus made impurity diffusion zones can be thereby stabilized, and eventually electric characteristics of enhancement type, static induction type semiconductor device can be sufficiently made stable.

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Neyagawa, Japan

Kazushi Kataoka