US 2003/0155622 A1Published application

Acceleration sensor and method of manufacture therof

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsKiyoshi Ishibashi, Makio Horikawa, Mika Okumura

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Abstract

An object of the present invention is to provide an acceleration sensor which is inexpensive and accomplishes its small-size and light-weight structure, and a manufacturing method thereof. In order to achieve the above-mentioned object, a sensor unit (17) provided on a base (11) is sealed by a cap (13) joined to a frame portion (19) of the base (11) in an eutectic manner. The cap (13) includes a cap main body (13a) made of a semiconductor material having a conductive property and a metal film 13 provided on the circumferential edge of the cap main body (13a). The frame portion (19) includes a frame main body (19a) made of doped polysilicon, a diffusion preventive film (19b) selectively provided on the frame main body (19a), and a joining layer (19c). The joining layer has one area as a conductive portion made of a conductive material, and the other area as a joining portion made of a semiconductor.

Claims10

Dependent claims

An acceleration sensor comprising:

a base (11);
and
a cap (13) attached to said base, wherein
said cap has:
a cap main body (13a) formed by a conductive semiconductor material;
and
a metal film (13b) formed on a circumferential edge thereof by using a metal material which can undergo an eutectic bonding with a semiconductor for joining, and
said base has:
a substrate (15);
a sensor unit (17) formed on the surface of said substrate, and having a function of detecting acceleration;
and
a frame portion (19) formed on said surface of said substrate in a manner so as to externally surround said sensor unit, at least one portion of a contact face making contacting with said circumferential edge of said cap being formed by said semiconductor for joining, with said at least one portion of said contact face being joined to said circumferential edge of said cap in an eutectic manner so that it cooperatively functions with said cap to seal said sensor unit from an external environment.

9 more elements

Dependencies are inferred from the claim text.