A MEMS motion sensor and its manufacturing method are provided. The sensor includes a MEMS wafer including a proof mass and flexible springs suspending the proof mass and enabling the proof mass to move relative to an outer frame along mutually orthogonal x, y and z axes. The sensor includes top and bottom cap wafers including top and bottom cap electrodes forming capacitors with the proof mass, the electrodes being configured to detect a motion of the proof mass. Electrical contacts are provided on the top cap wafer, some of which are connected to the respective top cap electrodes, while others are connected to the respective bottom cap electrodes by way of insulated conducting pathways, extending along the z axis from one of the respective bottom cap electrodes and upward successively through the bottom cap wafer, the outer frame of the MEMS wafer and the top cap wafer.

A rotation rate sensor includes a substrate and a drive structure that is movable relative to the substrate and is fastened to the substrate via a spring system that includes first and second spring components that each connects the drive structure and the substrate and that are joined by an intermediate piece, the drive structure being joined to the intermediate piece via the first portion, and the intermediate piece or a center area, which is at least partially situated between the first and second portions, being joined to the substrate via the second portion, the first and/or second portions having a respective varying base area in a respective main extension direction of the first and second portions, respectively.

A rotation rate sensor includes a substrate and a drive structure that is movable relative to the substrate and is fastened to the substrate via a spring system that includes first and second spring components that each connects the drive structure and the substrate and that are joined by an intermediate piece, the drive structure being joined to the intermediate piece via the first portion, and the intermediate piece or a center area, which is at least partially situated between the first and second portions, being joined to the substrate via the second portion, the first and/or second portions having a respective varying base area in a respective main extension direction of the first and second portions, respectively.

A micro-electromechanical device includes a semiconductor substrate, in which a first microstructure and a second microstructure of reference are integrated. The first microstructure and the second microstructure are arranged in the substrate so as to undergo equal strains as a result of thermal expansions of the substrate. Furthermore, the first microstructure is provided with movable parts and fixed parts with respect to the substrate, while the second microstructure has a shape that is substantially symmetrical to the first microstructure but is fixed with respect to the substrate. By subtracting the changes in electrical characteristics of the second microstructure from those of the first, variations in electrical characteristics of the first microstructure caused by changes in thermal expansion or contraction can be compensated for.

A micro-electromechanical device includes a semiconductor substrate, in which a first microstructure and a second microstructure of reference are integrated. The first microstructure and the second microstructure are arranged in the substrate so as to undergo equal strains as a result of thermal expansions of the substrate. Furthermore, the first microstructure is provided with movable parts and fixed parts with respect to the substrate, while the second microstructure has a shape that is substantially symmetrical to the first microstructure but is fixed with respect to the substrate. By subtracting the changes in electrical characteristics of the second microstructure from those of the first, variations in electrical characteristics of the first microstructure caused by changes in thermal expansion or contraction can be compensated for.

A physical quantity sensor includes a substrate, a movable body that faces the substrate, a fixed portion that is fixed to the substrate, and a support beam that couples the movable body to the fixed portion. The movable body is displaceable with the support beam as a rotation axis, and includes, in a plan view, a first mass that is located on one side of a second direction with respect to the rotation axis, and a second mass that is located on the other side. Each of the first mass and the second mass has a plurality of through-holes which penetrate through the movable body and each of which has a square shape as an opening shape. When damping is indicated by C, and a minimum value of the damping is indicated by Cmin, C1.5Cmin.

A physical quantity sensor includes a substrate, a movable body that faces the substrate, a fixed portion that is fixed to the substrate, and a support beam that couples the movable body to the fixed portion. The movable body is displaceable with the support beam as a rotation axis, and includes, in a plan view, a first mass that is located on one side of a second direction with respect to the rotation axis, and a second mass that is located on the other side. Each of the first mass and the second mass has a plurality of through-holes which penetrate through the movable body and each of which has a square shape as an opening shape. When damping is indicated by C, and a minimum value of the damping is indicated by Cmin, C1.5Cmin.

Microelectromechanical system (MEMS) inertial sensors exhibiting reduced parasitic capacitance are described. The reduction in the parasitic capacitance may be achieved by forming localized regions of thick dielectric material. These localized regions may be formed inside trenches. Formation of trenches enables an increase in the vertical separation between a sense capacitor and the substrate, thereby reducing the parasitic capacitance in this region. The stationary electrode of the sense capacitor may be placed between the proof mass and the trench. The trench may be filled with a dielectric material. Part of the trench may be filled with air, in some circumstances, thereby further reducing the parasitic capacitance. These MEMS inertial sensors may serve, among other types of inertial sensors, as accelerometers and/or gyroscopes. Fabrication of these trenches may involve lateral oxidation, whereby columns of semiconductor material are oxidized.

Microelectromechanical system (MEMS) inertial sensors exhibiting reduced parasitic capacitance are described. The reduction in the parasitic capacitance may be achieved by forming localized regions of thick dielectric material. These localized regions may be formed inside trenches. Formation of trenches enables an increase in the vertical separation between a sense capacitor and the substrate, thereby reducing the parasitic capacitance in this region. The stationary electrode of the sense capacitor may be placed between the proof mass and the trench. The trench may be filled with a dielectric material. Part of the trench may be filled with air, in some circumstances, thereby further reducing the parasitic capacitance. These MEMS inertial sensors may serve, among other types of inertial sensors, as accelerometers and/or gyroscopes. Fabrication of these trenches may involve lateral oxidation, whereby columns of semiconductor material are oxidized.

The MEMS gyroscope has a mobile mass carried by a supporting structure to move in a driving direction and in a first sensing direction, perpendicular to each other. A driving structure governs movement of the mobile mass in the driving direction at a driving frequency. A movement sensing structure is coupled to the mobile mass and detects the movement of the mobile mass in the sensing direction. A quadrature-injection structure is coupled to the mobile mass and causes a first and a second movement of the mobile mass in the sensing direction in a first calibration half-period and, respectively, a second calibration half-period. The movement-sensing structure supplies a sensing signal having an amplitude switching between a first and a second value that depend upon the movement of the mobile mass as a result of an external angular velocity and of the first and second quadrature movements. The first and second values of the sensing signal are subtracted from each other and compared with a stored difference value to supply information of variation of the scale factor.