A physical quantity sensor comprising:
- three axes orthogonal to each other being defined as an X axis, a Y axis, and a Z axis;
- a substrate;
- a first fixed electrode and a dummy electrode provided on the substrate, the first fixed electrode and the dummy electrode extending orthogonal to the Z axis;
- and
- a movable body provided to be swingable with respect to the substrate about a rotation axis along the Y axis, the movable body having first and second surfaces outwardly opposite to each other, the first surface facing the substrate, the movable body including:
- a first mass facing the first fixed electrode along the Z axis;
- and
- a torque generator continuously extending from the first mass and facing the dummy electrode,
- wherein, on the first surface of the first mass,
- a first region to an n-th region, n being an integer equal to or greater than 2, are provided so as to face the first fixed electrode with a gap therebetween, a step is provided between adjacent regions, and the first region to the n-th region are disposed in order from a closest region to the rotation axis, each cross section along an XZ plane of the first region to the n-th region being in a rectangular shape having a top mass surface and a bottom mass surface that are parallel to each other, the XZ plane extending along the X axis and the Z axis, wherein the first fixed electrode faces a plurality of regions among the first region to the n-th region, and the dummy electrode has the same potential as the movable body,
- a first recess is provided on the second surface of the first region, and a first through hole group is arranged on a bottom recess surface of the first recess,
- an n-th recess is provided on the second surface of the n-th region, and an n-th through hole group is arranged on a bottom recess surface of the n-th recess,
- wherein an opening area of each of through holes of the n-th through hole group is larger than an opening area of each of through holes of the first through hole group, and
- a depth of the n-th recess is shallower than a depth of the first recess, and
- ends of the first region to the n-th region on a side far from the rotation axis are set as a first end to an n-th end,
- in a cross-sectional view along the Y axis,
- in a state where the movable body is maximally displaced around the rotation axis toward the substrate, a first virtual straight line having a smallest angle with the X axis passes through two ends of the first end to the n-th end,
- a second virtual straight line extends along a main surface of the first fixed electrode,
- a first normal line with respect to the first fixed electrode intersects with an end of the first fixed electrode closest to the rotation axis and extends along the Z axis,
- a second normal line with respect to the first fixed electrode intersects with an end of the first fixed electrode farthest from the rotation axis and extends along the Z axis,
- the first virtual straight line and the second virtual straight line do not intersect with each other in a region between the first normal line and the second normal line, and
- the first and second virtual straight lines and the second normal line pass through the torque generator, and
- a thickness along the Z axis of the first region is larger than a thickness along the Z axis of a subsequent region that is located adjacent to the first region.