Acceleration sensor and method of manufacture thereof

An acceleration sensor comprising:

• a base;
• and
• a cap attached to said base, wherein
• said cap includes:
• a cap main body formed by a conductive semiconductor material, said cap main body including a circumferential edge;
• and
• a metal film formed on said circumferential edge by using a metal material, and
• said base includes:
• substrate;
• a sensor unit formed on the surface of said substrate, and having a function of detecting acceleration;
• and
• a frame portion formed on said surface of said substrate in a manner so as to externally surround said sensor unit, having a contact face making contact with said circumferential edge of said cap at least one portion of which is formed by a semiconductor for joining, wherein said at least one portion of said contact face is 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 its external environment,
• wherein
• said frame portion includes:
• a conductive frame main body formed on said surface of said substrate;
• and
• a joining layer formed on said frame main body, and joined to said metal layer of said cap in an eutectic manner, and
• said joining layer includes:
• a conductor portion formed by a conductive material and located in an area of one portion of the upper face of said frame main body;
• and
• a joining portion formed by said semiconductor for joining and located in an area other than said area on the upper face of the frame main body having said conductor portion;
• wherein
• a wiring pattern formed on a said substrate and said frame main body of said frame portion are electrically connected to each other.