Patent ID: 8156827

Claim:
An external force detection device comprising: a substrate including an upper layer, a lower layer, and an intermediate layer interposed between the upper layer and the lower layer; wherein the substrate includes: a weight portion; a supporting portion arranged so as to be spaced away from the weight portion; and a beam portion thinner than the weight portion in a stacking direction in which the upper layer, the intermediate layer, and the lower layer of the substrate are stacked, the beam portion connecting the supporting portion to the weight portion at least one connecting point; a space in which the weight portion can move is provided around the weight portion; the weight portion is displaced in accordance with an external force to cause the beam portion to deform; and an etched groove is provided in at least the upper layer and the lower layer of the substrate and defines a gap portion between the weight portion and the supporting portion, and wall surfaces of the etched groove have a three-dimensional structure.