Patent ID: 8487389

Claim:
A one-dimensional acceleration sensor comprising: a structure made of a semiconductor substrate having a constant thickness, comprising: a support made of the semiconductor substrate, patterned by a first through trench extending through said semiconductor substrate excepting a portion, disposed outside said first through trench and provided with bonding pads; a flexible beam patterned by a pair of second through trenches continuous with opposite ends of said first through trench, said second through trenches extending in one direction inside said support and through said semiconductor substrate, said flexible beam having a significantly narrower width than the thickness of said semiconductor substrate, extending from said portion of said support to a distal end in said one direction, and having four piezo resistors disposed at both edges on a proximal side of said flexible beam and at both edges on a distal side of said flexible beam; and a weight continuous with the distal end of said flexible beam, said weight being patterned by said first through trench and said second through trenches, having a pair of symmetrical first portions sandwiching said flexible beam therebetween and a second portion coupling said pair of first portions and the distal end of the flexible beam inside said support, and having a center of gravity at a position on a longitudinal center line of the flexible beam, displaced from said distal end of said flexible beam toward said proximal side; and wirings formed above said semiconductor substrate, and made from a same wiring layer, said wirings serially connecting each two piezo resistors at a same edge among said four piezo resistors, and leading interconnection points of the serial connections, distal ends of two piezo resistors on the distal side in common, and proximal ends of two piezo resistors on the proximal side, to said bonding pads.