Resonant inertial microsensor with variable thickness produced by surface engineering

A MEMS resonant sensor comprising:

• a first area fabricated in a substrate using micromachining technology, the first area having a first thickness, wherein the first area forms at least one seismic mass movable in a plane parallel to a substrate surface, and said first area being comprised of a first upper surface and a first lower surface, both extending parallel to said substrate surface;
• a second area fabricated in the substrate using micromachining technology, the second area having a second thickness, wherein the second thickness is less than half the first thickness, and wherein the second area forms a resonator, said resonator comprising a second upper surface and a second lower surface, the second upper surface and the second lower surface both extending parallel to said substrate surface, said resonator configured for capacitive excitation, said resonator being for detecting a movement of said seismic mass in said plane parallel to said substrate;
• and
• a hinge fabricated in the substrate using micromachining technology, the hinge to maintain the at least one seismic mass in a plane parallel to the substrate surface, said hinge comprising a third upper surface and a third lower surface, the third upper surface and the third lower surface both extending parallel to said substrate surface, the hinge and the resonator being anchored at one end to a same surface of said seismic mass, said same surface being perpendicular to said substrate surface, and at another end to said substrate,
• said first upper surface, said second upper surface and said third upper surface being in a same common plane parallel to said substrate surface, or said first lower surface, said second lower surface and said third lower surface being in a same common plane parallel to said substrate surface.