Micro-mechanical device with elastic assembly of variable elastic constant

Abstract

Embodiments of the present disclosure relate to a micro-mechanical device having an elastic assembly with a variable elastic constant. A micro-mechanical device comprises a semiconductor body, a first mobile structure, an elastic assembly coupled to the first mobile structure and to the semiconductor body and adapted to undergo a deformation in one direction, and at least one abutment element. The elastic assembly is configured to enable oscillation of the first mobile structure as a function of a force applied to the elastic assembly. The first mobile structure, the abutment element and the elastic assembly are arranged relative to each other in such a way that, when the force is less than a force threshold, the elastic assembly operates with a first elastic constant, and when the force is greater than the threshold force, the first mobile structure comes into contact with the abutment element and generates a deformation of the elastic assembly which operates with a second elastic constant different from the first elastic constant.

Description

Technical Field

[0001] This disclosure relates to micromechanical devices with elastic components having variable elastic constants. Background Technology

[0002] It is well known that there is a desire to efficiently detect and measure acceleration and impact via sensors with small size that are easy to integrate. Common applications include the monitoring of impacts in electronic devices such as mobile phones and smartwatches, for example, to detect car accidents or situations where a person falls to the ground due to discomfort, fainting, or illness.

[0003] Currently, the market offers low-G sensors (such as accelerometers and gyroscopes) suitable for detecting low accelerations (e.g., full-scale range of 16g ​​or 32g) and high-G sensors (e.g., full-scale range of 128g) suitable for detecting high accelerations. The former is used to detect the normal movements of operators equipped with electronic devices that integrate sensors (e.g., the movement of a mobile phone near the operator's ear or the wrist to which a smartwatch is attached), while the latter can detect high-intensity accelerations (as well as anomalous events).

[0004] To enable electronic devices to detect both low and high accelerations, known solutions envision integrating two types of accelerometers within the same device. However, the presence of two different accelerometers in the same electronic device presents several disadvantages, such as the need for more solder pads and increased complexity of control circuitry (e.g., dedicated ASICs, PCBs, or CPUs), a generally larger integration area, lower portability of the electronic device, and higher manufacturing costs.

[0005] In view of these drawbacks, patent document US2006 / 107743A1 discloses an accelerometer structure capable of achieving two different sensitivities in corresponding and different operating modes. Specifically, in one embodiment (in... Figure 1A(Represented by reference numeral 1a in the attached figure) The aforementioned accelerometer includes a vibrating mass 2 fixed to a first end 3a of a first spring element 3 having an elongated shape. Furthermore, the first spring element 3 is fixed to a support 5 at its second end 3b opposite to the first end 3a. Additionally, a second spring element 4, having an elongated shape and having first ends 4a and second ends 4b opposite to each other, is fixed to the support 5 at its second end 4b. The first spring element 3 and the second spring element 4 have a main extension along a first direction orthogonal to the main extension of the support 5 (e.g., orthogonal to the surface of the support 5), therefore, the first spring element 3 and the second spring element 4 are arranged to be parallel to each other about the first direction. Furthermore, they are aligned with each other in a direction perpendicular to a second direction orthogonal to the first direction. In use, the first spring element 3 is deflected in a direction perpendicular to its main extension by a force F (e.g., gravity) acting in the second direction. When the force F equals a threshold force F... th At this time, the first spring element 3 deflects, causing it to contact the first end 4a of the second spring element 4 at a portion of its bottom surface 3c. For forces less than the threshold force F... th For a force F, the accelerometer 1a has a first value K1 of the elastic constant (which depends exactly on the characteristics of the first spring element 3); for a force F greater than the threshold value... th The force F applied to the accelerometer 1a results in a second value K2 (depending on the characteristics of the second spring element 4) of elastic constant greater than the first value K1. Therefore, the presence of the second spring element 4 allows the stiffness of the accelerometer 1a to be changed according to the applied force F.

[0006] According to different embodiments of the accelerometer disclosed in the same patent document US2006 / 107743A1 (in... Figure 1B (Represented by reference numeral 1b in the attached figure), the vibrating mass 2 is connected to the support 5 via a third spring element 7, which has a tapered shape that gradually decreases from the end in contact with the support 5 to the end in contact with the vibrating mass 2. In use, the shape of the third spring element 7 allows for a non-linear distribution of the elastic constant, and thus a stiffness of the accelerometer 1b that varies according to the applied force F (particularly logarithmically).

[0007] However, accelerometer 1a exhibits low mechanical stability because spring elements 3 and 4 may be overstressed and suffer damage or failure due to mutual contact during impact or under any significant acceleration. Conversely, in the case of accelerometer 1b, it is difficult to theoretically predict the true curve of stiffness in a precise manner because it depends on multiple structural, usage, and process factors. Summary of the Invention

[0008] In various embodiments, this disclosure provides micromechanical devices that overcome the problems of the prior art.

[0009] In one or more embodiments of this disclosure, a micromechanical device is provided, comprising: a semiconductor body; a first movable structure having a first mass configured to oscillate relative to the semiconductor body in a plane direction; an elastic component having an elastic constant mechanically coupled to the first movable structure and the semiconductor body and configured to extend and contract in that direction; and at least one abutment element. The elastic component is configured to enable oscillation of the first movable structure according to a force applied to the first movable structure in that direction. The first movable structure, the abutment element, and the elastic component are arranged relative to each other in such a way that when the force applied to the first movable structure is less than an abutment force threshold, the first movable structure does not contact the abutment element, and the elastic component operates with a first elastic constant; and when the force applied to the first movable structure is greater than the abutment force threshold, the first movable structure contacts the abutment element, and under the applied force, deformation of the elastic component is generated, such that the elastic component operates with a second elastic constant different from the first elastic constant. Attached Figure Description

[0010] To better understand this disclosure, preferred embodiments thereof will now be described by way of non-limiting example only, with reference to the accompanying drawings, in which:

[0011] Figure 1A and Figure 1B This is a cross-sectional view of the corresponding accelerometer of a known type;

[0012] Figure 2 This is a top view of a micromechanical device according to an embodiment of the present disclosure;

[0013] Figure 2A and Figure 2B The corresponding operating mode is shown. Figure 2 Micromechanical devices;

[0014] Figure 3 This is a top view of a further embodiment of the micromechanical device according to the present invention;

[0015] Figure 3A and Figure 3B It is in the corresponding operating mode. Figure 3 A top view of a micromechanical device;

[0016] Figure 3C This is a top view of a further embodiment of the micromechanical device according to the present disclosure;

[0017] Figure 4 This is a top view of a further embodiment of the micromechanical device according to the present invention;

[0018] Figure 4A and Figure 4B It is in the corresponding operating mode. Figure 4 A top view of a micromechanical device;

[0019] Figure 5 This is a top view of a further embodiment of the micromechanical device according to the present disclosure;

[0020] Figure 5A and Figure 5B It is in the corresponding operating mode. Figure 5 A top view of a micromechanical device;

[0021] Figure 6A This indicates that when using micro-mechanical devices, by Figure 3 The curve of the electrical signal generated at the output of the micromechanical device as a function of acceleration; and

[0022] Figure 6B It means Figure 4 The graph shows how the stiffness of a micromechanical device varies with the displacement of a sense mass belonging to the micromechanical device relative to its stationary position. Detailed Implementation

[0023] Specifically, the accompanying drawings illustrate a three-axis Cartesian system defined by a first axis X, a second axis Y, and a third axis Z that are orthogonal to each other.

[0024] In the following description, elements common to different embodiments are indicated by the same reference numerals.

[0025] Furthermore, in the following description, the term "substantially" is used to refer to properties that are considered to have undergone first-order verification. For example, if two elements moving relative to a reference point are said to be "substantially" fixed relative to each other, it means that even if there may be relative movement between them, this relative movement is negligible compared to the movement relative to the reference point (e.g., the relative movement is less than 5% of the movement of each element relative to the reference point). Similarly, if an element exhibits "substantially" zero deformation along an axis, it means that the possible deformation of the element is negligible compared to the extension of the element itself along the aforementioned axis (e.g., the deformation is less than 5% of the extension of the element along the axis).

[0026] Figure 2 A micromechanical device 50 (hereinafter also referred to as sensor 50) configured to detect acceleration is shown according to one embodiment. Figure 2 This is a top view of sensor 50 (i.e., in the XY plane). Figure 2The elements shown are only those useful for understanding this embodiment, and no elements or components that are not important to this disclosure, although present in the completed sensor, are shown.

[0027] Sensor 50 includes a semiconductor body 51 of a semiconductor material (such as silicon (Si)) having a surface 51a extending parallel to a first plane XY defined by a first axis X and a second axis Y (i.e., a third axis Z is orthogonal to surface 51a). Sensor 50 also includes a first moving structure 53 having a first mass M1 and a second moving structure 55 having a second mass M2 greater than the first mass M1. Hereinafter, the first moving structure 53 will be referred to as the "first seismic mass," and the second moving structure 55 will be referred to as the "second seismic mass."

[0028] For example, both the first vibrating mass 53 and the second vibrating mass 55 are semiconductor materials (such as silicon or polycrystalline silicon) and extend at different heights parallel to the surface 51a of the semiconductor body 51 along the axis Z relative to the surface 51a.

[0029] The first vibrating mass 53 is physically coupled to the semiconductor body 51 via a first spring assembly 57 (specifically, the first spring or first elastic element 57a of the first spring assembly 57, and the second spring or second elastic element 57b of the first spring assembly 57), while the second vibrating mass 55 is physically coupled to the semiconductor body 51 via a second spring assembly 59 (specifically, the first spring or first elastic element 59a of the second spring assembly 59, and the second spring or second elastic element 59b of the second spring assembly 59). For example, both the first elastic assembly 57 and the second elastic assembly 59 are made of a semiconductor material (such as silicon or polycrystalline silicon) and undergo deformation along a first axis X (i.e., they elongate / shorten). In other words, both the first spring assembly 57 and the second spring assembly 59 have a corresponding axis along which they deform parallel to the first axis X. Furthermore, the first spring assembly 57 and the second spring assembly 59 deform in the same direction of deformation 60.

[0030] In the exemplary embodiment described, the first portions 57a, 59a and the second portions 57b, 59b of the elastic elements 57, 59 are serpentine springs. Specifically, these serpentine springs are planar and are obtained using MEMS technology (i.e., semiconductor fabrication methods). More specifically, the serpentine spring may include first portions extending parallel to each other and parallel to a second axis Y, and second portions extending parallel to each other and parallel to a first axis X. The first and second portions are connected to each other and arranged to form a serpentine path: each first portion is connected to a corresponding second portion at its opposite ends along the second axis Y; and each second portion is connected at its opposite ends along the first axis X to a corresponding first portion except for the two second portions (each second portion is located at a corresponding end of the path along the first axis X and is connected to only one corresponding first portion).

[0031] Each spring 57a, 57b of the first spring assembly 57 has a corresponding first end 57a', 57b' and a corresponding second end 57a”, 57b”, which are opposite to each other along the first axis X. Each spring 59a, 59b of the second spring assembly 59 has a corresponding end 59a', 59b' and a corresponding end 59a”, 59b”, which are opposite to each other along the first axis X.

[0032] Specifically, the distance between end 57a' and end 57a” of the first spring 57 of the first spring assembly 57, measured along axis X, is indicated by reference numeral L. 1a Identification. The distance between end 57b' and end 57b” of the second spring 57 of the first spring assembly 57, measured along axis X, is indicated by reference numeral L. 1b Identification. The distance between end 59a' and end 59a” of the first spring 59a of the second spring assembly 59, measured along axis X, is indicated by reference numeral L. 2a Identification. The distance between end 59b' and end 59b” of the second spring 59 of the second spring assembly 59, measured along axis X, is indicated by reference numeral L. 2b Logo.

[0033] The springs 57a and 57b of the first spring assembly 57 have corresponding first elastic constants K1 (having the same value), and the springs 59a and 59b of the second spring assembly 59 have corresponding second elastic constants K2 (having the same value as each other but different from K1 (e.g., greater than K1)).

[0034] exist Figure 2In the embodiment, there are two springs 57a and 57b, so the equivalent elastic constant of the first spring assembly 57 is given by 2K1, and there are two springs 59a and 59b, so the equivalent elastic constant of the second spring assembly 59 is given by 2K2. Generally, for any number N1 of springs in the first spring assembly 57, the equivalent elastic constant of the first spring assembly 57 is given by N1·K1, and for any number N2 of springs in the second spring assembly 59, the equivalent elastic constant of the second spring assembly 59 is given by N2·K2.

[0035] Each spring 57a, 57b of the first spring assembly 57 is coupled to a corresponding first fixing element 64' via a corresponding end 57a', 57b', which is coupled to a surface 51a of the semiconductor body 51 (specifically, each first fixing element 64 is fixed relative to the surface of the semiconductor body 51). Furthermore, each spring 57a, 57b of the first spring assembly 57 is coupled to a first vibrating mass 53 at a corresponding end 57a', 57b'. In detail, in the embodiment discussed by way of example, the first vibrating mass 53 has a first side 53a and second side 53b opposite to each other along a first axis X, and each end 57a', 57b' is fixed relative to a corresponding end between the first side 53a and the second side 53b. Therefore, the first vibrating mass 53 is disposed along the first axis X between the first spring 57a and the second spring 57b of the first spring assembly 57.

[0036] In addition, Figure 2 In the middle, the second vibrating mass 55 has a cavity 62, in which the first vibrating mass 53, the first spring assembly 57 and the first fixing element 64' are installed.

[0037] Each spring 59a, 59b of the second spring assembly 59 is coupled to a corresponding second fixing element 64” via a corresponding end 59a', 59b'. The second fixing element 64” is in turn coupled to the semiconductor body 51 (specifically, the second fixing element 64” is fixed relative to the surface 51a of the semiconductor body 51). Furthermore, each spring 59a, 59b of the second spring assembly 59 is coupled to a second vibrating mass 55 at a corresponding end 59a”, 59b”. In detail, in the discussed embodiment, the second vibrating mass 55 has a first side surface 55a and a second side surface 55b opposite each other along the first axis X, and each end 59a”, 59b” is fixed relative to a corresponding end between the first side surface 55a and the second side surface 55b. Therefore, the second vibrating mass 55 is disposed along the first axis X between the first spring 59a and the second spring 59b of the second spring assembly 59.

[0038] The first vibrating mass 53 also includes multiple stopping elements 66a (e.g., in...). Figure 2 In the middle, four stop elements 66a), and the second vibrating mass 55 includes a corresponding plurality of housing elements 66b (e.g., in Figure 2 In the middle, there are four housing elements 66b. The stop element 66a and the housing elements 66b form the abutment assembly 66.

[0039] The stop element 66a is a protrusion of the first vibrating mass 53, while the housing element 66b is a corresponding portion of the second vibrating mass 55, having a corresponding cavity and / or recess. Figure 2 In the embodiment illustrated by way of example, both the stop element (protrusion) 66a and the housing element 66b (cavity) have a generally rectangular shape, extending primarily parallel to the second axis Y. Specifically, the first vibrating mass 53 and the second vibrating mass 55 are arranged such that each stop element 66a extends within the cavity of each corresponding housing element 66b, or in other words, each stop element 66a is partially surrounded by the corresponding housing element 66b to form a corresponding abutment assembly 66. In the absence of an external force acting along the axis X, each stop element 66a does not contact the corresponding housing element 66b. Each stop element 66a has a first sidewall 67a and a second sidewall 67b that are opposite each other along the first axis X, while each housing element 66b has a first sidewall 67c and a second sidewall 67d that are opposite each other along the first axis X and respectively face the first sidewall 67a and the second sidewall 67b of the corresponding stop element 66a. For each contact structure 66, the distance between sidewalls 67a and 67c is equal to the first length L1, while the distance between sidewalls 67b and 67d is equal to the second length L2.

[0040] Furthermore, the first vibrating mass 53 includes one or more first electrodes 68a (moving electrodes), such as protrusions (e.g., having a generally rectangular shape in the XY plane), which are displaced in a fixed manner relative to the first vibrating mass 53 during use. One or more second electrodes 68b (fixed electrodes) are fixed relative to the semiconductor body 51 (particularly surface 51a).

[0041] Each of the second electrodes is further divided into a first portion 68b' and a second portion 68b', which are separated from each other. The first electrode 68a extends between the first portion 68b' and the second portion 68b'. More specifically, each of the first electrodes 68a faces each other and is disposed between the first portion 68b' and the second portion 68b' of the corresponding second electrode 68b.

[0042] The first electrode 68a and the second electrode 68b form the measuring structure 68 of the sensor 50. In use, the measuring structure 68 is adapted to detect displacement along a first axis X of the first vibrating mass 53 and the second vibrating mass 55 in a capacitive manner; these displacements indicate external forces (e.g., acceleration) acting on the sensor 50.

[0043] Specifically, the surfaces of the first portions 68b' of the first electrode 68a and the second electrode 68b, which face each other directly, form a first capacitor 68'. Similarly, the surfaces of the second portions 68b' of the first electrode 68a and the second electrode 68b, which face each other directly, form a second capacitor 68'. The distance between the first electrode 68a and the first portion 68b' (along the axis X) is determined by a reference d. c1 This indicates that the distance between the first electrode 68a and the second part 68b is determined by reference d. c2 express.

[0044] Furthermore, the first blocking element 70' and the second blocking element 70" are fixed relative to the semiconductor body 51 (especially relative to the surface 51a of the semiconductor body 51). Figure 2 Two blocking elements 70' are shown as an example, with a distance L between the two blocking elements 70' and the first side 55a of the second vibrating mass 55 along the first axis X. 1block . Figure 2 Similarly, two blocking elements 70” are shown, which are set to be L along the first axis X and at a distance L from the second side 55b of the second vibrating mass 55. 2block .

[0045] In detail, to prevent direct contact between the first electrode 68a and parts 68b' and 68b'", the distance d is... c1 Designed to have d c1 >L1+L 1block The value, and the distance d c2 Designed to have d c2 >L2+L 2block The value of .

[0046] During the use of sensor 50, the first electrode 68a is biased at a first voltage V1, and the second electrode 68b is biased at a second voltage V2. Specifically, the first voltage V1 and the second voltage V2 are the same (V1 = V2).

[0047] Due to usage, the first distance d c1 Second distance d c2The capacitance of capacitors 68', 68" may vary relative to the applied force, depending on the external force applied to sensor 50 (as already stated, causing displacement of the first vibrating mass 53). The capacitance measurement can be performed using techniques known per se (e.g., via a transimpedance amplifier).

[0048] When the sensor 50 is at rest, no external force is applied to it, so both the first vibrating mass 53 and the second vibrating mass 55 are at rest.

[0049] The first vibrating mass 53 has a first center of mass B1 and the second vibrating mass 55 has a second center of mass B2. Under static conditions:

[0050] The first centroid B1 and the second centroid B2 coincide in the plane XY (B1=B2=B2). stat );

[0051] The first path L1 and the second path L2 are identical (L1 = L2 = L...). stop );

[0052] First distance d c1 Second distance d c2 They are the same (d) c1 =d c2 =d rest );

[0053] First length L 1a Second length L 1b They are the same (L) 1a =L 1b =L 1rest );

[0054] First length L 2a Second length L 2b They are the same (L) 2a =L 2b =L 2rest );and

[0055] First distance L 1block Second distance L 2block They are the same (L) 1block =L 2block =L blockmax ).

[0056] Figure 2A The sensor 50 is shown under the first operating condition, wherein the external force (having a value below a threshold F) th The first value F1 is applied to the sensor 50. In this specification, for example, the external force is considered to be a force acting in the direction of the first axis X (in...). Figure 2A(From left to right); however, what is described below also clearly applies to the case where the external forces act in opposite directions. Due to its inertia, the apparent force on the first vibrating mass 53 is equal to the external force applied to the sensor 50, but in the opposite direction (due to...). Figure 2A The reference system shown relative to the semiconductor body 51 is not inertial. Apparent forces cause relative motion of the first vibrating mass 53 relative to the semiconductor body 51. Specifically:

[0057] In the plane XY, the position of the first mass center B1 relative to the stationary mass center B stat The displacement occurs along the first axis X, while the second center of mass B2 is positioned relative to the stationary center of mass B. stat Basically coincident;

[0058] The first length L1 is less than L stop And the second length L2 is greater than L stop ;

[0059] First distance d c1 Less than distance d rest And the second distance d c2 Greater than distance d rest ;

[0060] First length L 1a Less than the rest length L 1rest And the second length L 1b Greater than the rest length L 1rest ;

[0061] First length L 2a Second length L 2b They are essentially the same and essentially equal to the rest length L. 2rest ;

[0062] First distance L 1block Second distance L 2block They are basically the same and equal to the distance L blockmax .

[0063] Therefore, considering this as an example, N1 = 1, N2 = 1, in Figure 2A Under the first operating condition, sensor 50 has a resonant pulsation ω according to the following mathematical expression. res :

[0064]

[0065] Figure 2B The sensor 50 is shown under a second operating condition, wherein the external force applied to the sensor 50 has a value greater than or equal to a threshold F. thThe second force value F2. For the same reason as described above, the first vibrating mass 53 relative to... Figure 2 The stationary position displacement is such that the stop element 66a abuts against the corresponding housing element 66b. Specifically, the first center of mass B1 is relative to position B along the first axis X in the plane XY. stat The (stationary center of mass) is displaced, and the first vibrating mass 53 is in direct physical contact with the second vibrating mass 55 at the first sidewall 67a of the stop element 66a and the first sidewall 67c of the housing element 66b. Under this operating condition, the second vibrating mass 55 is also in direct physical contact with the semiconductor body 51 and its surroundings under the thrust of the first vibrating mass 53. Figure 2 The displacement at rest position is shown. Therefore, the second centroid B2 also moves relative to the rest position B along the first axis X in the plane XY. stat Displacement. Therefore, under the second operating conditions, the second vibrating mass 55 moves in a fixed manner relative to the first vibrating mass 53. In particular:

[0066] The first length L1 is zero and the second length L2 is a length L. stop Twice as much;

[0067] First distance d c1 Less than the stationary distance d rest (In addition, it is smaller than) Figure 2A First distance d c1 ), and the second distance d c2 Greater than the stationary distance d rest (In addition, it is greater than) Figure 2A The second distance d c2 );

[0068] First length L 1a Less than the first rest length L 1rest (In addition, it is smaller than) Figure 2A First length L 1a ), and the second length L 1b Greater than the first stationary length L 1rest (In addition, it is greater than) Figure 2A The second length L 1b );

[0069] First length L 2a Less than the second rest length L 2rest (In addition, it is smaller than) Figure 2A First length L 2a ), and the second length L 2b Greater than the second stationary length L 2rest (In addition, it is greater than) Figure 2A The second length L 2b );

[0070] First distance L1block Less than the maximum distance L blockmax And the second distance L 2block Greater than the maximum distance L blockmax .

[0071] Therefore, considering N1=1 and N2=1 as examples, in Figure 2B Under the second operating condition, the resonant pulsation ω of sensor 50 is obtained according to the following mathematical expression. res :

[0072]

[0073] Specifically, if the external force applied to sensor 50 has a value greater than or equal to the maximum force value F max (greater than the threshold force value F) th If the value of ) is specified, then the second vibrating mass 55 abuts against the first blocking element 70' at a portion of the first side surface 55a of the second vibrating mass 55. In other words, the first distance L 1block It is zero, and the second distance L 2block For the maximum distance L blockmax Twice that of the first vibrating mass 53. Therefore, the blocking element 70 enables the limitation of any possible oscillations of the second vibrating mass 55 (and thus also the first vibrating mass 53), thereby preventing them from exceeding the critical amplitude threshold that could cause damage or malfunction to the sensor 50.

[0074] Figure 3 Different embodiments of the sensor are shown (denoted herein by reference numeral 150). The sensor 150 includes a semiconductor body 51 and a moving structure 153 (hereinafter referred to as the "vibrating mass") having its own mass M3. For example, the vibrating mass 153 is made of a semiconductor material (such as silicon or polycrystalline silicon) and extends parallel to the surface 51a of the semiconductor body 51. The vibrating mass 153 has a first side surface 153a and a second side surface 153b that are opposite each other along a first axis X.

[0075] Vibration mass 153 by (previous reference) Figure 2 The first spring assembly 57 (described) provides support and has a corresponding deformation axis extending in a first deformation direction 160' parallel to the first axis X. Specifically, the ends 57a” and 57b” of the springs forming the spring assembly 57 contact and are fixed relative to the first side surface 153a and the second side surface 153b, respectively. Therefore, a vibrating mass 153 is disposed along the first axis X between the first spring 57a and the second spring 57b of the spring assembly 57.

[0076] Additionally, at least one second spring assembly 159 is present. When the sensor 150 is in a static condition, i.e., when the vibrating mass 153 is not subjected to an external force that causes its displacement, the second spring assembly 159 is physically separated from the vibrating mass 153; under different operating conditions of the sensor 150, when an external force acts on the vibrating mass 153 and causes it to displace in the direction of the axis X, the vibrating mass 153 abuts against the contact area of ​​the second spring assembly 159.

[0077] For example, the second spring assembly 159 is made of a semiconductor material (such as silicon or polycrystalline silicon), and its elastic constant K3 is different from (e.g., higher than) the elastic constant K1 of the first spring assembly 57. The deformation axis of the second spring assembly 159 extends parallel to axis X and intersects with respect to the deformation axis of the first spring assembly 57. The second spring assembly 159 includes a first elastic element (spring) 159a and a second elastic element (spring) 159b.

[0078] In the embodiment described by way of example, the first elastic element 159a and the second elastic element 159b are both serpentine springs, i.e., arranged to form strips extending in a serpentine manner (as previously described). Each elastic element 159a, 159b has a corresponding end 159a', 159b' coupled to the semiconductor body 51 and a corresponding end 159a”, 159b” coupled to the vibrating mass 153. In particular, each elastic element 159a, 159b of the second spring assembly 159 is coupled to a corresponding fixing element 164 via the corresponding end 159a', 159b', the fixing element 164 being coupled to the surface 51a of the semiconductor body 51 (in particular, each fixing element 164 is fixed relative to the surface of the semiconductor body 51).

[0079] exist Figure 3 In the embodiment, there are four elastic elements 159a, 159b, such that the equivalent elastic constant of the second spring assembly 159 is given by 4K3. Typically, for any number N3 of elastic elements in the second spring assembly 159, the equivalent elastic constant of the second spring assembly 159 is given by N3·K3.

[0080] Each first elastic element 159a has an extension measured along the first axis X between the respective ends 159a' and 159a'", equal to the first length L. 3a Furthermore, each second elastic element 159b has an extension measured along the first axis X between its respective ends 159b' and 159b'", equal to the second length L. 3b .

[0081] Each elastic element 159a, 159b of the second spring assembly 159 includes a corresponding stop element 166a at a position corresponding to the respective end 159a”, 159b”, which is obtained by a terminal protrusion having a main extension parallel to the second axis Y (i.e., perpendicular to the oscillation direction of the vibrating mass 153).

[0082] Vibrating mass 153 has a notch, and stop element 166a extends within the notch. A portion of vibrating mass 153 including the notch forms a corresponding housing element 166b for stop element 166a. Each stop element 166a and the corresponding housing element 166b form a corresponding abutment assembly 166.

[0083] Each stop element 166a has a first sidewall 167a and a second sidewall 167b that are opposite each other along a first axis X, while each housing element 166b has a first sidewall 167c and a second sidewall 167d that are opposite each other along a first axis X, and the first sidewall 167c and the second sidewall 167d respectively face the first sidewall 167a and the second sidewall 167b of the corresponding stop element 166a. For each abutment assembly 166, the distance between sidewalls 167a and 167c is equal to a first length L3, and the distance between sidewalls 167b and 167d is equal to a second length L4.

[0084] Each stop element 166a is in conjunction with Figure 2 The stop element 66a operates in a similar manner to the reference element, while the housing element 166b has a similar design to the reference element. Figure 2 The function of housing element 66b has been described.

[0085] As better described below, under operating conditions, the vibrating mass 153 and each elastic element 159a, 159b are adjacent to each other via each stop element 166a and the corresponding housing element 166b.

[0086] In addition, as already referenced Figure 2 The described first vibrating mass 153 includes a first electrode 68a and a second electrode 68b, thereby forming a reference to Figure 2 The measurement structure described is 68.

[0087] Additionally, a blocking element 70 is present, facing the first side 153a and the second side 153b of the vibrating mass 153. Specifically, at least one (in...) Figure 3 (Two elements are present) The first blocking element 70' is separated from the first side surface 153a by a distance L along the first axis X. 3block And at least one (in Figure 3 (Two elements are present in the middle) The second blocking element 70” is separated from the second side surface 153b by a distance L along the first axis X.4block It can be noted that the distance d c1 Greater than L3+L 3block And the distance to d c2 Greater than L4+L 4block .

[0088] In use, as previously discussed, sensor 150 is biased to perform a measurement of the applied external force.

[0089] like Figure 3 The sensor 150 shown is in a static condition; no external force is applied to it, therefore the vibrating mass 153 is in a static position. Specifically, in the plane XY, the vibrating mass 153 has a center of mass B (which, under static conditions, is equal to the position of the center of mass B). stat ).also:

[0090] Lengths L3 and L4 are the same and equal to the stopping length L. stop ;

[0091] First distance d c1 Second distance d c2 They are the same and equal to the stationary distance d rest ;

[0092] First length L 1a Second length L 1b They are identical and equal to the first rest length L 1rest ;

[0093] First length L 3a Second length L 3b They are identical and equal to the second rest length L 3rest ;and

[0094] First distance L 3block Second distance L 4block They are identical and equal to the maximum distance L blockmax .

[0095] Figure 3A The sensor 150 is shown under the first operating condition, wherein the external force (having a force value F less than a threshold force value) th A first force (F1) is applied to sensor 150. As previously discussed, vibrating mass 153 undergoes relative motion with respect to semiconductor body 51. Specifically, in the plane XY, the center of mass B is relative to the stationary center of mass B. stat Displacement along the first axis X. Additionally:

[0096] The first length L1 is greater than the stopping length L. stop And the second length L2 is less than the stopping length L. stop ;

[0097] First distance d c1 Less than the stationary distance d rest And the second distance d c2 Greater than the stationary distance d rest ;

[0098] First length L 1a Less than the first rest length L 1rest And the second length L 1b Greater than the first stationary length L 1rest ;

[0099] The first length L3a and the second length L3b are the same and equal to the rest length L. 3rest ;and

[0100] First distance L 3block Less than the maximum distance L blockmax And the second distance L 4block Greater than the maximum distance L blockmax .

[0101] Therefore, considering examples N1=1 and N3=1, in Figure 3A Under the first operating condition, the resonant pulsation ω of sensor 150 is obtained according to the following mathematical expression. res :

[0102]

[0103] Figure 3B The sensor 150 is shown under a second operating condition, wherein the external force applied to the sensor 150 has a value greater than or equal to a threshold F. th The second force value F2. For the same reason as mentioned above, the vibrating mass 153 relative to... Figure 3 The static position displacement, and each stop element 166a is supported on a corresponding housing element 166b (i.e., the vibrating mass 153 is in contact with the stop element 166a of the second spring assembly 159). Specifically, in the plane XY, the center of mass B is relative to the stationary center of mass B. stat The displacement of the position along the first axis X is greater than Figure 3A As shown in the diagram, the vibrating mass 153 is in direct physical contact with the second spring assembly 159. Furthermore:

[0104] The first length L1 is the length L stop The length L1 is twice that of L2, and the second length L2 is zero.

[0105] First distance d c1 Less than the stationary distance d rest (In addition, it is smaller than) Figure 3A First distance dc1 ), and the second distance dc2 Greater than the stationary distance d rest (In addition, it is greater than) Figure 3A The second distance d c2 );

[0106] First length L 1a Less than the first rest length L 1rest (In addition, it is smaller than) Figure 3A First length L 1a ), and the second length L 1b Greater than the first stationary length L 1rest (In addition, it is greater than) Figure 3A The second length L 1b );

[0107] First length L 3a Less than the second rest length L 3rest And the second length L 3b Greater than the second stationary length L 3rest ;and

[0108] First distance L 3block Less than the maximum distance L blockmax (In addition, it is smaller than) Figure 3A First distance L 3block ), and the second distance L 4block Greater than the maximum distance L blockmax (In addition, it is greater than) Figure 3A The second distance L 4block ).

[0109] Therefore, considering examples N1=1 and N3=1, in Figure 3B Under the second operating condition, the resonant pulsation ω of sensor 150 is obtained according to the following mathematical expression. res :

[0110]

[0111] Specifically, if the external force applied to sensor 150 has a value greater than or equal to the maximum force value F max The value (greater than the threshold force value F) th If the vibrating mass 153 is supported on a portion of the first side surface 153a of the vibrating mass 153, then the vibrating mass 153 is supported on a first blocking element 70'. Therefore, the blocking element 70 is able to limit any possible oscillations of the vibrating mass 153, thereby preventing them from exceeding a critical threshold of amplitude that could cause damage or malfunction to the sensor 150.

[0112] also, Figure 3C A further embodiment of sensor 150 (denoted herein by reference numeral 150') is shown, similar to... Figure 3One embodiment is shown.

[0113] In particular, Figure 3C In this configuration, a vibrating mass 153 surrounds and defines at least one through-hole or cavity 180, in which a second set of springs 189 extends (instead of) Figure 3 The second spring assembly 159). In particular, the vibrating mass 153 has sidewalls 180a and 180b, which are opposite to each other along the first axis X and directly face the cavity 180.

[0114] The second set of springs 189 includes a first spring (elastic element) 189a and a second spring (elastic element) 189b, each spring having its elastic constant K3', for example, higher than the elastic constant K1 of the first spring assembly 57. When the sensor 150' is at rest, i.e., when the vibrating mass 153 is not displaced by an external force, the second set of springs 189 is physically separated from the vibrating mass 153. Under different operating conditions of the sensor 150', when an external force acts on the vibrating mass 153, causing it to displace in the X-axis direction, the vibrating mass 153 abuts against the contact area 186a of the second spring assembly 159.

[0115] Each spring 189a, 189b is a planar spring obtained using MEMS technology, specifically a spring comprising a strip (e.g., made of semiconductor material) extending in a plane XY and having a main extension parallel to the second axis Y and a width W1 measured along the first axis X. The first spring 189a extends between its end 189a' and its end 189a', which are opposite each other relative to the second axis Y, and the second spring 189b extends between its end 189b' and its end 189b', which are opposite each other relative to the second axis Y. The ends 189a', 189b' are fixed relative to corresponding fixing elements 184 coupled to the surface 51a of the semiconductor body 51 (in particular, each fixing element 184 is fixed relative to the surface of the semiconductor 51 and extends within the cavity 180). An abutment region 186a is located at the ends 189a', 189b'. Specifically, the abutment region 186a is fixed relative to the ends 189a”, 189b” and has a width W2, measured along the first axis X, that is greater than the width W1. Alternatively, the abutment region 186a is part of a spring 189a, 189b having a width W2, measured along the first axis X, that is greater than the width W1.

[0116] For sensor 150' operating under conditions where an external force acts on vibrating mass 153, causing displacement along its axis X, one of the sidewalls 180a and 180b is supported on the abutment region 186a of the second spring assembly 159, causing the corresponding springs 189a and 189b to deflect (deform) along the first axis X. The length measured along axis X between the abutment region 186a and the sidewalls 180a and 180b is here determined by L. 3’ L 4’ Identification, and with Figure 3 The lengths L3 and L4 are similar.

[0117] Therefore, each contact area 186a and the sidewalls 180a, 180b of the vibrating mass 153 facing the contact area 186a form a corresponding contact assembly 186, which allows the elastic constant of the sensor 150' to be changed, as already referenced. Figure 3-3B As described.

[0118] In addition, Figure 3C In the embodiment shown, the abutment region 186a has a circular shape (i.e., a circular profile) in the plane XY in order to better distribute the mechanical stress caused by the contact between the abutment region 186a and the sidewalls 180a, 180b of the vibrating mass 153.

[0119] As in Figure 3 In addition, there is a blocking element 70. The blocking element 70 extends in the cavity 180 (see...). Figure 3C They are fixed relative to the surface 51a of the semiconductor body 51 (in particular, each blocking element 70 is fixed relative to the corresponding fixing element 184) and face one of the sidewalls 180a, 180b of the vibrating mass 153, with a distance L between them. 3block’ L 4block’ ,and Figure 3 Distance L 3block L 4block resemblance.

[0120] exist Figure 3C In the embodiment, there are four springs 189a and 189b, such that the equivalent elastic constant of the second set of springs 189 is changed from 4K. 3’ Given. Typically, for any number N3' of springs in the second group of springs 189, the equivalent elastic constant of the second group of springs 189 is given by N3'·K. 3’ Provided.

[0121] Figure 4Different embodiments of the sensor are shown (denoted herein by reference numeral 250). The sensor 250 includes a semiconductor body 51 and a moving structure (hereinafter referred to as the "vibrating mass") 253 having a mass M4. For example, the vibrating mass 253 is made of a semiconductor material (such as silicon or polycrystalline silicon) and extends parallel to a surface 51a of the semiconductor body 51. The vibrating mass 253 has a through-hole or cavity 262. The vibrating mass 253 surrounds and defines the cavity 262. The vibrating mass 253 is externally defined by a first side surface 253a and a second side surface 253b that are opposite each other along a first axis X. The vibrating mass 253 also has a third side surface 253c and a fourth side surface 253d that are opposite each other along the first axis X and directly face the cavity 262.

[0122] Vibrating mass 253 is physically coupled to semiconductor body 51 via at least one spring assembly 259 extending in cavity 262. For example, spring assembly 259 is made of semiconductor material (such as silicon or polycrystalline silicon) and has corresponding axial deformation in a deformation direction 260 parallel to the first axis X. Spring assembly 259 includes a first spring (elastic element) 259a and a second spring (elastic element) 259b. In one embodiment (not shown), springs 259a, 259b are planar springs obtained using MEMS technology; more specifically, the springs include a plurality of turns defining a serpentine path (as previously described; particularly, springs 259a, 259b include first and second portions similar to those defined for the springs above). Each turn is defined, in a manner known per se, as the minimum whole of the first and second portions of each spring 259a, 259b (having a turn length, not shown, measured along the first axis X), and is formed by replicating it multiple times by translating the turn length in the deformation direction 260. Figure 4 In the embodiments, springs 259a and 259b are planar springs obtained using MEMS technology. More specifically, the springs include multiple turns. Each turn extends in a plane XY and includes a strip made of, for example, a semiconductor material arranged to form a polygonal closed path (e.g., a rectangular path, including a short side parallel to the first axis X and a long side parallel to the second axis Y).

[0123] The number of turns equals the total number of turns n foldtot .

[0124] The first spring 259a and the second spring 259b of the spring assembly 259 each have corresponding ends 259a' and 259b' that are opposite to each other along the first axis X. Each spring 259a, 259b is coupled via its corresponding ends 259a', 259b' to a corresponding fixing element 264 fixed relative to the semiconductor body 51 (specifically, relative to the surface 51a of the semiconductor body 51). Furthermore, each spring 259a, 259b of the second spring assembly 59 is coupled to the vibrating mass 253 via its corresponding ends 259a', 259b'. Specifically, the ends 259a', 259b' coupled to the vibrating mass are in contact with the third side surface 253c and the fourth side surface 253d of the vibrating mass 253, respectively.

[0125] The first spring 259a has an extension that is measured along a first axis X between end 259a' and end 259a'”, and is equal to a first length L. a The second spring 259b has an extension that is measured along the first axis X between end 259b' and end 259b”, and is equal to the first length L. b Furthermore, as will be discussed more fully below, each spring 259a, 259b includes at least one stop element 266a, arranged to abut against the vibrating mass 253 under the operating conditions of the sensor 250. The stop element 266a is a protrusion of each portion 259a, 259b having a main extension parallel to the second axis Y and extending within a recess of the vibrating mass 253. Hereinafter, the portion of the vibrating mass 253 including the recess is referred to as the housing element 266b. The stop element 266a and the housing element 266b form an abutment assembly 266.

[0126] Each stop element 266a has a first sidewall 267a and a second sidewall 267b that are opposite to each other along a first axis X, while each housing element 266b has a first sidewall 267c and a second sidewall 267d that are opposite to each other along the first axis X and respectively face the first sidewall 267a and the second sidewall 267b of the corresponding stop element 266a. For each abutment assembly 266, the distance between sidewalls 267a and 267c is equal to a first length L5, and the distance between sidewalls 267b and 267d is equal to a second length L6.

[0127] For spring 259a of spring assembly 259, a first region 261a' and a second region 261a' are identified. The first region 261a' includes a turn contained between the end 259a' and the stop element 266a, and the second region 261a' includes a turn contained between the end 259a' and the stop element 266a. For spring 259b of spring assembly 259, a first region 261b' and a second region 261b' are identified. The first region 261b' includes a turn contained between the end 259b' and the stop element 266a, and the second region 261b' includes a turn contained between the end 259b' and the stop element 266a.

[0128] The length measured along axis X between end 259a” and stop element 266a is given by L. a’ Identification. It can be noted that, since the stop element 266a has a rectangular shape in this example, the length L... a’ The length is defined between end 259a' and the axis passing through the center of mass of stop element 266a and parallel to axis Y. The length measured along axis X between end 259a' and stop element 266a is given by L. a The x symbol. Similarly, the length L... a” The length is defined between end 259a' and the aforementioned axis passing through the center of mass of stop element 266a and parallel to axis Y. The length measured along axis X between end 259b" and stop element 266a is hereby defined by L. b’ Identifier. Similarly, length L b’ The length is defined between end 259b' and the aforementioned axis passing through the center of mass of stop element 266a and parallel to axis Y. The length measured along axis X between end 259b' and stop element 266a is here defined by L. b” Identifier. Similarly, length L b” It is defined between the end 259b' and the aforementioned axis that passes through the center of mass of the stop element 266a and is parallel to the axis Y.

[0129] Therefore, for spring 259a, the length L a’ and length L a” The sum equals the first length L a Therefore, for spring 259b, the length L b’ and length L b” The sum equals the second length L b In the embodiment described by way of example, for each part 259a, 259b, the length L a’ L a” L b’ and L b”Under the stationary condition of sensor 250, the number of turns between the ends 259a”, 259b” and the stop element 266a is equal to the number of turns between the stop element 266a and the ends 259a’, 259b’. However, according to another embodiment not shown, the length L a’ and L a” The number of turns between the sensor 250 and the stop element 266a can differ from the number of turns between the stop element 266a and the end 259a' under stationary conditions. Similarly, the length L b’ and L b” The sensors 250 are different from each other under static conditions, and the number of turns between the end 259b” and the stop element 266a is different from the number of turns between the stop element 266a and the end 259b’.

[0130] In addition, as referenced Figure 2 As already described, the vibration mass 253 includes a first electrode 68a and a second electrode 68b forming the measuring structure 68.

[0131] Furthermore, there are blocking elements 70 facing the first side surface 253a and the second side surface 253b of the vibrating mass 253. Specifically, at least one (in Figure 4 In the middle, the two first blocking elements 70' are at a distance L from the first side surface 253a of the vibrating mass 253 along the first axis X. 5block At a distance of, and at least one (at) Figure 4 In the middle, the two second blocking elements 70” are spaced L apart from the second side surface 253b of the vibrating mass 253 along the first axis X. 6block At a distance of .

[0132] In use, as previously discussed, sensor 250 is biased to perform measurements of externally applied forces.

[0133] As in Figure 4 The sensor 250 shown is in a static condition, with no external force applied to it, therefore the vibrating mass 253 is in a static position. Specifically, in the plane XY, the vibrating mass 253 has a position B under static conditions. stat The coincident centroids are B. Furthermore:

[0134] The first length L5 and the second length L6 are the same as each other and equal to the stopping length L. stop ;

[0135] First distance d c1 Second distance d c2 They are the same and equal to the stationary distance d rest ;

[0136] First length L a Second length L b They are identical and equal to the rest length L rest ;and

[0137] First distance L 5block Second distance L 6block They are identical and equal to the maximum distance L blockmax .

[0138] Figure 4A The sensor 250 is shown under the first operating condition, wherein the external force (having a force value F below a threshold value) th A first force (F1) is applied to sensor 250. As previously discussed, there is relative motion between vibrating mass 253 and semiconductor body 51, which causes deformation of spring assembly 259. Specifically, in plane XY, the center of mass B along the first axis X is relative to the stationary center of mass B. stat Displacement. Furthermore:

[0139] The first length L5 is greater than the stop length L. stop And the second length L6 is less than the stop length L stop ;

[0140] First distance d c1 Less than the stationary distance d rest And the second distance d c2 Greater than the stationary distance d rest ;

[0141] First length L a Greater than the rest length L rest And the second length L b Less than the rest length L rest ;and

[0142] First distance L 5block Less than the maximum distance L blockmax And the second distance L 6block Greater than the maximum distance L blockmax .

[0143] In detail, since the stop element 266a has not yet made direct physical contact with the corresponding housing element 266b (i.e., they do not abut against each other), the stress is distributed across the entire spring assembly 259, and all turns undergo deformation. Under these operating conditions, for each part 259a, 259b, the number of turns undergoing deformation is equal to n. fold1 n fold1 This is then equal to the total number of turns n foldtot (n fold1 =n foldtot ).

[0144] As is well known, the elastic constant of a spring with a deformation axis depends on the number of turns of the spring and the length of the spring measured along the deformation axis (in particular, it is inversely proportional to the number of turns and the length). Therefore, under the first operating conditions, each spring 259a, 259b of the spring assembly 259 has a number of turns n that effectively participate in the deformation. fold1 The first elastic constant is K4. Figure 4 In the embodiment, there are two springs 259a and 259b, such that the equivalent elastic constant of the spring assembly 259 under the first condition is given by 2K4. Typically, for any number N4 of springs in the spring assembly 259, the equivalent elastic constant of the spring assembly 259 under the first operating condition is given by N4·K4.

[0145] Therefore, considering the example N4 = 1, in Figure 4A Under the first operating condition, the resonant pulsation ω of sensor 250 is obtained by applying the following mathematical expression. res :

[0146]

[0147] Figure 4B The sensor 250 is shown under a second operating condition, wherein the external force applied to the sensor 250 has a force value F greater than or equal to a threshold force value. th The second force value F2. For the same reason as mentioned above, the vibrating mass 253 relative to... Figure 4 The stationary position displacement is such that the stop element 266a abuts against the corresponding housing element 266b. Specifically, in the plane XY, the center of mass B along the first axis X is relative to the stationary center of mass B. stat The displacement is greater than Figure 4A As shown in the diagram, the springs 259a and 259b of the spring assembly 259 are configured to be in direct physical contact with the vibrating mass 253. Furthermore:

[0148] The first length L5 is the stop length L stop Twice that of the first distance d, and the second length L6 is zero; the first distance d c1 Less than the stationary distance d rest (In addition, it is smaller than) Figure 4A First distance d c1 ), and the second distance d c2 Greater than the stationary distance d rest (In addition, it is greater than) Figure 4A The second distance d c2 );

[0149] First length L a Greater than the rest length L rest (In addition, it is greater than) Figure 4A First length L a ), and the second length L b Less than the rest length L rest (In addition, it is smaller than) Figure 4A The second length L b );and

[0150] First distance L 5block Less than the maximum distance L blockmax (In addition, it is smaller than) Figure 4A First distance L 5block ), and the second distance L 6block Greater than the maximum distance L blockmax (In addition, it is greater than) Figure 4A The second distance L 6block ).

[0151] In detail, since the stop element 266a is in direct physical contact (i.e., abutting) with the corresponding housing element 266b, further stress (i.e., the difference between the applied stress and the minimum stress required to abut the stop element 266a against the corresponding housing element 266b) is distributed only over the turns of the second regions 261a”, 261b” of the springs 259a and 259b that undergo further deformation: in other words, these turns are included between the stop element 266a and the ends 259a' (259b' respectively). Hereinafter, the reference numeral n... fold2 This indicates the number of turns in each second region 261a”, 261b” belonging to springs 259a and 259b.

[0152] In Figure 4 In the example provided, we have n fold2 =n foldtot / 2. Therefore, each spring 259a, 259b of the spring assembly 259 has a second number of turns n depending on the second operating condition. fold2 The second elastic constant K5 (the second elastic constant K5 is higher than the first elastic constant K4). Figure 4 In the embodiment, there are two springs 259a and 259b, such that the equivalent elastic constant of the spring assembly 259 under the second operating condition is given by 2K5. Typically, for any number N4 of springs in the spring assembly 259, the equivalent elastic constant of the spring assembly 259 under the second operating condition is given by N4·K5.

[0153] Therefore, considering the example N4 = 1, in Figure 4B Under the second operating condition, the resonant pulsation ω of sensor 250 is obtained according to the following mathematical expression. res :

[0154]

[0155] Specifically, if the external force applied to sensor 250 has a value greater than or equal to the maximum force value F max The value (greater than the threshold force value F) th Then the vibrating mass 253 is supported on the first blocking element 70'.

[0156] Figure 5 A further embodiment of a micromechanical device 350 (hereinafter referred to as "sensor 350") according to one aspect of the present disclosure is shown. Sensor 350 includes: a semiconductor body 51; a first moving structure (hereinafter referred to as "vibrating mass") 353 having a first mass M5; and a second moving structure (hereinafter referred to as "vibrating mass") 355 having a second mass M6 (e.g., greater than the first mass M5). For example, both the first vibrating mass 353 and the second vibrating mass 355 are made of a semiconductor material (such as silicon or polycrystalline silicon) and extend parallel to the surface 51a of the semiconductor body 51. The second vibrating mass 355 surrounds and defines a first via or cavity 362. Furthermore, the second vibrating mass 355 includes: a first sidewall 355a and a second sidewall 355b directly facing the first cavity 362 and opposing each other along a first axis X; and a third sidewall 355c and a fourth sidewall 355d opposing each other along the first axis X and externally defining the second vibrating mass 355.

[0157] The first vibrating mass 353 is completely contained within the cavity 362. The first vibrating mass 353 then has a second through-hole or cavity 363. The first vibrating mass 353 surrounds and defines the cavity 363. Furthermore, the first vibrating mass 353 includes: a first sidewall 353a and a second sidewall 353b directly facing the cavity 363 and opposing each other along the first axis X; and a third sidewall 353c and a fourth sidewall 353d facing the first cavity 362 and opposing each other along the first axis X. The first vibrating mass 353 is connected via a first set of springs (similar to those already referred to) completely contained within the second cavity 363. Figure 2 The first spring assembly 57 (described herein, and therefore referred to hereinafter as the first spring assembly 57) is physically coupled to the semiconductor body 51. Specifically, the fixed ends 57a' and 57b' of the two springs 57a and 57b are fixed relative to the same fixing element 64 (which in turn extends in the second cavity 363 in a manner fixed relative to the semiconductor body 51, particularly relative to the surface 51a of the semiconductor body 51). Conversely, the ends 57a' and 57b' of the springs 57a and 57b of the first spring assembly 57 are fixed relative to the first sidewall 353a and the second sidewall 353b of the first vibrating mass 353, respectively.

[0158] The first vibrating mass 353 and the second vibrating mass 355 are transmitted via a second spring assembly 359 extending in the first cavity 362 (e.g., Figure 2 The spring assemblies 59 are physically coupled to each other. In particular, the second spring assembly 359 includes a first spring (elastic element) 359a and a second spring (elastic element) 359b. Each spring 359a, 359b is a planar spring obtained using MEMS technology, and more specifically, a spring having multiple turns defining a serpentine path.

[0159] The first spring 359a extends between its end 359a' and its end 359a”, while the second spring 359b extends between its end 359b' and its end 359b”. The ends 359a' and 359b' are fixed relative to the first sidewall 355a and the second sidewall 355b of the second vibrating mass 355, respectively.

[0160] Spring 359a has a length measured along axis X between ends 359a' and 359a" and is indicated by reference numeral L. 4a Identification; Spring 359b has a length measured along axis X between ends 359b' and 359b”, indicated by reference numeral L. 4b Logo.

[0161] Conversely, ends 359a” and 359b” are fixed relative to the third sidewall 353c and the fourth sidewall 353d of the first vibrating mass 353, respectively.

[0162] Each spring 359a and 359b has an elastic constant K6 that is higher than the elastic constant K1 of each part 57a and 57b. Figure 5 In the embodiment, there are two springs 359a and 359b such that the equivalent elastic constant of the second spring assembly 259 is equal to 2K6. Typically, given any number N5 of springs in the second spring assembly 359, the equivalent elastic constant of the second spring assembly 359 is given by N5·K6. Similarly, in... Figure 5 In the embodiment, there are two springs 57a and 57b such that the equivalent elastic constant of the first spring assembly 57 is equal to 2K1. Typically, given any number N1 of springs in the first spring assembly 57, the equivalent elastic constant of the first spring assembly 57 is given by N1·K1.

[0163] Furthermore, the first vibrating mass 353 includes at least one third through-hole or cavity 365. The first vibrating mass 353 surrounds and defines the cavity 365. A measuring structure extends within the cavity 365. The measuring structure is similar to a reference. Figure 2The measurement structure 68 described herein is therefore denoted by the same reference numerals. In particular, the first vibrating mass 353 includes at least one first electrode 68a, which extends in and faces the third cavity 365 and is disposed (along the first axis X) between the first portion 68b' and the second portion 68b” of the measurement structure 68.

[0164] Furthermore, at least one first contact element 380a and at least one second contact element 380b are fixed relative to the surface 51a of the semiconductor body 51 and face the third sidewall 355c and the fourth sidewall 355d of the second vibrating mass 355, respectively. The distance between the first contact element 380a and the third sidewall 355c of the second vibrating mass 355 is equal to the first contact length L. cont1 Furthermore, the distance between the second contact element 380b and the fourth sidewall 355d of the second vibrating mass 355 is equal to the second contact length L. cont2 Contact length L cont1 L cont2 Less than the stationary distance d rest The value (d) rest It is the stationary distance between electrodes 68a and 68b', which is equal to the stationary distance between electrodes 68a and 68b'". Therefore, the second vibrating mass 355 is disposed between the first contact element 380a and the second contact element 380b along the first axis X, so that the first vibrating mass 353 and the second vibrating mass 355 can move relative to the semiconductor body 51 in a deformation direction 360 parallel to the first axis X.

[0165] Furthermore, there is a blocking element 70, which faces the third sidewall 353c and the fourth sidewall 353d of the first vibrating mass 353. Specifically, at least one (in Figure 5 In the middle, the two first blocking elements 70' and the third sidewall 353c of the first vibrating mass 353 are separated by a first distance L along the first axis X. 7block And at least one (in Figure 5 In the middle, the two second blocking elements 70” and the fourth sidewall 353d of the first vibrating mass 353 are separated by a second distance L along the first axis X. 8block The distance d from the first capacitor c1 Greater than L 7block And the distance of the second capacitor is d c2 Greater than L 8block .

[0166] In use, as previously discussed, sensor 350 is biased to perform a measurement of the applied external force.

[0167] As in Figure 5As shown in the static condition, no external force is applied to the sensor 350, therefore both the first vibrating mass 353 and the second vibrating mass 355 are stationary and in a static position. Specifically, the first vibrating mass 353 has a first center of mass B1, and the second vibrating mass 355 has a second center of mass B2. Under static conditions, in the plane XY, the first center of mass B1 and the second center of mass B2 coincide with each other and are at the static position B. stat Overlap. Furthermore:

[0168] First contact length L cont1 Second contact length L cont2 They are identical and equal to the rest length L contrest ;

[0169] First distance d c1 Second distance d c2 They are the same and equal to the stationary distance d rest ;

[0170] First length L 1a Second length L 1b They are identical and equal to the rest length L 1rest ;

[0171] First length L 4a Second length L 4b They are identical and equal to the rest length L 4rest ;and

[0172] First distance L 7block Second distance L 8block They are identical and equal to the maximum distance L blockmax .

[0173] Figure 5A The sensor 350 is shown under the first operating condition, wherein the external force (having a force value F below a threshold value) th A first force F1 is applied to sensor 350. The first vibrating mass 253 and the second vibrating mass 255 move relative to the semiconductor body 51 in a manner similar to that previously discussed. Specifically, considering that the stiffness of the second spring assembly 359 is greater than the stiffness of the first spring assembly 57, the first vibrating mass 353 and the second vibrating mass 355 move in a manner fixed relative to each other. In detail, both the first center of mass B1 and the second center of mass B2 are located in the plane XY along the first axis X relative to the stationary center of mass B. stat Their positions have shifted and essentially overlap. Furthermore:

[0174] First contact length L cont1 Less than the rest length L contrest And the second contact length L cont2Greater than the rest length L contrest ;

[0175] First distance d c1 Less than the stationary distance d rest And the second distance d c2 Greater than the stationary distance d rest ;

[0176] First length L 1a Greater than the first stationary length L 7rest And the second length L 1b Less than the rest length L 7rest ;

[0177] Length L 4a and length L 4b They are essentially the same and are essentially equal to the rest length L. 8rest ;and

[0178] First distance L 7block Less than the maximum distance L blockmax And the second distance L 8block Greater than the maximum distance L blockmax .

[0179] Therefore, considering examples N1=1 and N5=1, in Figure 5A Under the first operating condition, sensor 350 has a resonant pulsation ω according to the following mathematical expression. res :

[0180]

[0181] Figure 5B The sensor 350 is shown under a second operating condition, wherein the external force applied to the sensor 350 has a force value F greater than or equal to a threshold force value. th The second force value F2. For the same reason as described above, both the first vibrating mass 353 and the second vibrating mass 355 are relative to... Figure 5 The second vibrating mass 355 is supported on the first contact element 380a at the third sidewall 355c of the second vibrating mass 355. Specifically, in the plane XY, the first center of mass B1 and the second center of mass B2 are at their rest positions relative to the center of mass B. stat The corresponding displacement along the first axis X is greater than Figure 5A The displacement shown is given, and the first centroid B1 is relative to the rest position B of the centroid. stat The displacement is greater than the rest position B of the second mass center B2 relative to the mass center B. statThe displacement. Therefore, under the second operating condition, the second vibrating mass 355 is fixed relative to the semiconductor body 51, while the first vibrating mass 353 can oscillate and move further. Furthermore:

[0182] First contact length L cont1 The value is zero, and the second contact length L cont2 Let L be the rest length. contrest Twice as much.

[0183] First distance d c1 Less than the stationary distance d rest (In addition, it is smaller than) Figure 5A distance d c1 ), and the second distance d c2 Greater than the stationary distance d rest (In addition, it is greater than) Figure 5A distance d c2 );

[0184] First length L 1a Greater than the first stationary length L 1rest (In addition, it is greater than) Figure 5A Length L 1a ), and the second length L 1b Less than the first rest length L 1rest (In addition, it is smaller than) Figure 5A Length L 1b );

[0185] The first length L of the second spring assembly 359 4a Less than the second rest length L 2rest And the second length L 4b Greater than the second stationary length L 2rest ;and

[0186] First distance L 7block Less than the maximum distance L blockmax (In addition, it is smaller than) Figure 5A First distance L 7block ), and the second distance L 8block Greater than the maximum distance L blockmax (In addition, it is greater than) Figure 5A Distance L 8block ).

[0187] Therefore, considering examples N1=1 and N5=1, in Figure 5B Under the second operating condition, the resonant pulsation ω of sensor 350 is obtained according to the following mathematical expression. res :

[0188]

[0189] Therefore, the contact element 380 enables the limitation of any possible oscillations of the second vibrating mass 355, and the deformation of the second spring assembly 359 due to the inertia of the first vibrating mass 353 (in the second operating mode, the first vibrating mass 353 is no longer fixed relative to the second vibrating mass 355) thus provides a threshold mechanism for modifying the elastic response of the sensor 350.

[0190] Furthermore, if the external force applied to sensor 350 is greater than or equal to the maximum force value F max (greater than the threshold force value F) th When the value of ) is reached, the first vibrating mass 353 is supported on the first blocking element 70' at a portion of the third sidewall 353c of the first vibrating mass 353. In other words, the first distance L 7block It is zero, and the second distance L 8block For the maximum distance L blockmax Twice that of the first vibrating mass 353. Therefore, the blocking element 70 enables the limitation of any possible oscillations of the first vibrating mass 353, thereby preventing them from exceeding a critical threshold of amplitude that could cause damage or malfunction to the sensor 350.

[0191] The advantages provided are apparent from the study of the features disclosed in accordance with this disclosure.

[0192] In particular, this disclosure enables the provision of an accelerometer that exhibits a variable and / or nonlinear response to acceleration / deceleration. This allows a single sensor to measure different ranges of acceleration / deceleration and thus detect and distinguish events that are very different from each other. Specifically, having the same sensor that measures both low-value (e.g., equal to 16g or 32g) and high-value (e.g., equal to 128g) accelerations ensures savings in power consumption during operation, dedicated integration area, and the overall cost of the device housing the sensor.

[0193] More specifically, sensor 50 has two vibrating masses 53 and 55 and two spring assemblies 57 and 59. Low acceleration can be measured via the first vibrating mass 53, which deforms the first spring assembly 57 (while the second vibrating mass 55 is fixed relative to the semiconductor body 51, and the second spring assembly 59 undergoes substantially no deformation). High acceleration can then be measured when the vibrating masses 53 and 55 are abutting against each other and relatively fixed, contributing to the deformation of the first spring assembly 57 and the second spring assembly 59. Furthermore, the spring assemblies 57 and 59 do not have direct physical contact with each other, and this improves the mechanical stability of sensor 50 by reducing the stress borne by the spring assemblies 57 and 59 under impact conditions. In sensor 50, a threshold mechanism enabling modification of the elastic response of sensor 50 is provided by elements 66a and 66b. In use, the physical contact that may occur between elements 66a and 66b involves through-hole elements capable of withstanding high stresses. Therefore, no critical stress is reached, thus ensuring better mechanical stability of sensor 50.

[0194] Conversely, sensor 150 has a vibrating mass 153 and two sets of springs 57 and 159. Low acceleration can be measured via the deformation of the first spring assembly 57 caused by the vibrating mass 153 (while the second spring assembly 159 is not under stress), and high acceleration can be measured via the deformation of the vibrating mass 153 caused by both sets of springs 57 and 159. Furthermore, the elastic response of sensor 150 can be easily calculated via FEM (finite element modeling) simulation in a manner known per se. Specifically, as... Figure 6A As shown, when acceleration increases (positive value), the signal generated by sensor 150 exhibits a first linear stretch with a first slope, followed by a second linear stretch with a second slope, the second slope being less than the first slope. The first and second stretches are connected in a continuous manner (i.e., there is no zero-degree discontinuity, only a first-degree discontinuity). The curve of the signal generated by sensor 150 at negative acceleration (i.e., deceleration) is a mirror reflection of the curve at positive acceleration (specifically, symmetrical with respect to the origin).

[0195] Sensor 250 has a vibrating mass 253 and a spring assembly 259. The nonlinear elastic response of sensor 250 is obtained through the operation of stop element 266a and housing element 266b, which alter the characteristics of spring assembly 259 during use: by reducing the number of turns of spring assembly 259 capable of withstanding stress caused by applied external forces (i.e., by reducing the effective number of turns), the elasticity of spring assembly 259 changes, and therefore the response of sensor 250 changes. In this case, as... Figure 6BAs shown, as the displacement of the vibrating mass 253 increases, the stiffness of the spring assembly 259 (and therefore the overall stiffness of the sensor 250) exhibits a first linear stretch (indicating the first stiffness), followed by a second linear stretch (indicating the second stiffness). These two stretches are separated from each other by a zero-degree discontinuity in stiffness, which corresponds to the instant when physical contact occurs between the stop element 266a and the housing element 266.

[0196] The sensor 350 has two vibrating masses 353 and 355 and two sets of springs 57 and 359. Physical contact between the second vibrating mass 355 and a contact element 380 fixed relative to the semiconductor body 51 provides a threshold mechanism enabling the measurement of different ranges of acceleration. This decouples the vibrating masses 353 and 355 and activates the second spring assembly 359. The acceleration-dependent response at the output of the sensor 350 is similar to that of a reference sensor. Figure 6A The response described for sensor 150.

[0197] Furthermore, the elastic element of the sensor discussed earlier has a predominant extension and deformation direction parallel to the surface 51a of the semiconductor body 51. Specifically, external forces act in the deformation direction of the elastic element. This allows stress to be distributed effectively across the elastic element, thereby reducing the likelihood of damage or failure.

[0198] Finally, it is obvious that modifications and changes may be made to the disclosure and description herein without departing from the scope of this disclosure as defined by the appended claims.

[0199] Specifically, the measurement structure 68 can be interdigitated (i.e., it can include multiple first electrodes 68a and second electrodes 68b facing each other to form an array) to improve measurement sensitivity. Furthermore, the measurement structure 68 can be based on an effect different from the capacitive effect previously discussed. For example, the measurement structure 68 can be a structure of a type known per se, which enables resistive, piezoelectric, or optical detection.

[0200] Additionally, each stop element 66a (equivalently, 166a and 266a, and each contact element 380a, 380b) may include a crowned portion that, during mutual contact, is adapted to improve contact with the corresponding housing element 66b (correspondingly, 166b and 266b, and the second mass 355) and reduce the risk of adhesion to the corresponding housing element 66b. In particular, the sidewall of each stop element may be convex.

[0201] There may be multiple abutment components 66, 166, and 266, and their positions may differ from those described herein, as may the blocking element 70.

[0202] The various embodiments described above can be combined to provide further embodiments. These and other changes can be made to the embodiments based on the detailed description above. Generally, the terminology used in the following claims should not be construed as limiting the claims to the specific embodiments disclosed in the specification and claims, but should be interpreted to include all possible embodiments and the full scope of equivalents enjoyed by these claims. Therefore, the claims are not limited by the disclosure.

Claims

1. A micromechanical device, comprising: a semiconductor body; a first mobile structure having a first mass, configured to oscillate in a direction belonging to a plane, with respect to the semiconductor body; a second mobile structure; a resilient assembly having a spring constant, mechanically coupled to the first mobile structure and to the semiconductor body, and configured to extend and contract in the direction; and at least one abutment element, wherein the resilient assembly is configured to enable the oscillation of the first mobile structure as a function of a force applied in the direction to the first mobile structure, and wherein the first mobile structure, the abutment element and the resilient assembly are arranged with respect to each other in such a way that: when the force applied to the first mobile structure is less than an abutment force threshold, then the first mobile structure is not in contact with the abutment element, and the resilient assembly operates with a first spring constant; and when the force applied to the first mobile structure is greater than the abutment force threshold, then the first mobile structure is in contact with the abutment element, and a deformation of the resilient assembly is generated under the action of the applied force, so that the resilient assembly operates with a second spring constant different from the first spring constant; wherein the resilient assembly comprises a first spring and a second spring having a third spring constant greater than the first spring constant, the first mobile structure being mechanically coupled to the semiconductor body via the first spring, and the second mobile structure being mechanically coupled to the semiconductor body via the second spring.

2. The micromechanical device according to claim 1, wherein for an applied force less than the abutment force threshold, the deformation of the resilient assembly is a deformation of the first spring in the absence of a deformation of the second spring, and for an applied force greater than the abutment force threshold, the deformation of the resilient assembly is a deformation of both the first spring and the second spring.

3. The micromechanical device according to claim 1, wherein for an applied force less than the abutment force threshold, the resilient assembly operates with the first spring constant of the first spring, and for an applied force greater than the abutment force threshold, the resilient assembly operates with a second spring constant which is the sum of the first spring constant and the third spring constant.

4. The micromechanical device according to claim 1, wherein the second mobile structure comprises a recess having a side wall at least partially delimiting the abutment element, and the first mobile structure comprises at least one protrusion extending in the recess to cooperate in contact with the side wall of the recess when the applied force is equal to or greater than the abutment force threshold.

5. The micromechanical device according to claim 1, wherein the second mobile structure has a second mass greater than the first mass, and wherein, for an applied force lower than the abutment force threshold, a resonance pulsation of the micromechanical device is a function of the first elastic constant and of the first mass, and, for an applied force greater than the abutment force threshold, the resonance pulsation of the micromechanical device is a function of the first elastic constant, of the third elastic constant, of the first mass and of the second mass.

6. The micromechanical device of claim 1, wherein the second mobile structure has a through hole through which the first mobile structure extends, and wherein the abutment element is integrated in the second mobile structure and comprises a notch in the second mobile structure, a protrusion housed in the notch, for enabling, for an applied force lower than the abutment force threshold, a translation of the protrusion parallel to the direction, and for preventing, for an applied force greater than the abutment force threshold, the translation.

7. The micromechanical device of claim 1, wherein the first mobile structure comprises a notch having a lateral wall, and wherein the elastic assembly comprises at least one spring extending between a first end coupled to the first mobile structure and a second end coupled to a substrate, and comprises a protrusion fixed with respect to the spring, the spring comprises a first number of turns between the first end and the protrusion and a second number of turns between the second end and the protrusion, when the applied force is equal to or greater than the abutment force threshold during the oscillation, the protrusion extends in the notch to cooperate in contact with the lateral wall of the notch, so that, for an applied force lower than the abutment force threshold, the spring operates with the first elastic constant which is a function of a sum of the first number of turns and of the second number of turns, and, for an applied force greater than the abutment force threshold, the spring operates with the second elastic constant which is a function of the second number of turns.

8. The micromechanical device of claim 7, wherein the spring is a planar spring of the serpentine type.

9. The micromechanical device of claim 1, further comprising a second mobile structure, wherein the elastic assembly comprises a first spring operatively coupled between the semiconductor body and the second mobile structure, and a second spring operatively coupled between the first mobile structure and the second mobile structure, and wherein, for an applied force lower than the abutment force threshold, a deformation experienced by the first spring is greater than the deformation of the second spring, and, for an applied force greater than the abutment force threshold, the deformation of the second spring is equal to the deformation of the first spring.

10. The micromechanical device of claim 9, wherein the first spring has the first elastic constant and the second spring has a third elastic constant greater than the first elastic constant, and wherein, for an applied force lower than the abutment force threshold, the first elastic constant is greater than the third elastic constant, and, for an applied force greater than the abutment force threshold, the third elastic constant is greater than the first elastic constant. wherein, for an applied force smaller than the abutment force threshold, the elastic assembly operates with the first spring constant and, for an applied force greater than the abutment force threshold, the elastic assembly operates with the second spring constant, which is the sum of the first spring constant and the third spring constant.

11. The micro-mechanical device of claim 10, wherein the first moving structure has a first mass and the second moving structure has a second mass smaller than the first mass, and wherein, for an applied force smaller than the abutment force threshold, a resonance fluctuation of the micro-mechanical device is a function of the first spring constant, the first mass and the second mass, and, for an applied force greater than the abutment force threshold, the resonance fluctuation of the micro-mechanical device is a function of the first spring constant, the third spring constant and the second mass.

12. A micro-mechanical device, comprising: a semiconductor body; a first moving structure having a first mass configured to oscillate with respect to the semiconductor body in a direction belonging to a plane; an elastic assembly having a spring constant mechanically coupled to the first moving structure and to the semiconductor body and configured to extend and contract in the direction; and at least one abutment element, wherein the elastic assembly is configured to enable the oscillation of the first moving structure as a function of a force applied to the first moving structure in the direction, and wherein the first moving structure, the abutment element and the elastic assembly are arranged with respect to each other in such a way that: when the force applied to the first moving structure is smaller than an abutment force threshold, then the first moving structure is not in contact with the abutment element and the elastic assembly operates with a first spring constant; and when the force applied to the first moving structure is greater than the abutment force threshold, then the first moving structure is in contact with the abutment element and, under the action of the applied force, a deformation of the elastic assembly is generated so that the elastic assembly operates with a second spring constant different from the first spring constant, wherein the elastic assembly comprises a first spring and a second spring, the first moving structure being mechanically coupled to the semiconductor body via the first spring, the first moving structure and the second spring being arranged with respect to each other in such a way that, when the applied force is equal to or greater than the abutment force threshold, the first moving structure abuts an abutment portion of the second spring, so that, for an applied force smaller than the abutment force threshold, the deformation of the elastic assembly is a deformation of the first spring in the absence of a deformation of the second spring, and, for an applied force greater than the abutment force threshold, the deformation of the elastic assembly is a deformation of both the first spring and the second spring.

13. The micro-mechanical device according to claim 12, wherein the first mobile structure comprises a notch having a side wall at least partially delimiting the abutment element, and the abutment portion of the second spring comprises at least one protrusion extending in the notch to cooperate in contact with the side wall of the notch when the applied force is equal to or greater than the abutment force threshold.

14. The micro-mechanical device according to claim 12, wherein the first spring has the first elastic constant and the second spring has a third elastic constant, and wherein for an applied force lower than the abutment force threshold, the elastic assembly operates with the first elastic constant of the first spring, and for an applied force greater than the abutment force threshold, the elastic assembly operates with a second elastic constant which is the sum of the first elastic constant and the third elastic constant.

15. The micro-mechanical device according to claim 12, wherein the first mobile structure has a first mass and the second spring has a third elastic constant, and wherein for an applied force lower than the abutment force threshold, the resonance pulsation of the micro-mechanical device is a function of the first elastic constant and the first mass, and for an applied force greater than the abutment force threshold, the resonance pulsation of the micro-mechanical device is a function of the first elastic constant, the third elastic constant and the first mass.

16. The micro-mechanical device according to claim 14, wherein the elastic assembly comprises a N1 multiple of first springs each having the first elastic constant and a N2 multiple of second springs each having the third elastic constant, and wherein for an applied force lower than the abutment force threshold, the elastic assembly operates with an equivalent elastic constant equal to N1 times the first elastic constant, and for an applied force higher than the abutment force threshold, the elastic assembly operates with an equivalent elastic constant equal to the sum of N1 times the first elastic constant and N2 times the third elastic constant.

17. The micro-mechanical device according to claim 12, wherein the second spring comprises a planar spring obtained by MEMS technology.

18. The micro-mechanical device according to claim 13, wherein the second spring comprises a strip extending in the plane and having a first width measured along a main extension parallel to a first axis and along a second axis.

19. The micro-mechanical device according to claim 18, wherein an abutment region at an end portion of the second spring has a second width measured along the second axis, wherein the second width is greater than the first width.

20. A micro-mechanical device, comprising: a semiconductor body; a first mobile structure having a first mass configured to oscillate with respect to the semiconductor body in a direction belonging to a plane; a second mobile structure; an elastic assembly having an elastic constant mechanically coupled to the first mobile structure and to the semiconductor body and configured to extend and contract in the direction; an abutment element mechanically coupled to the second mobile structure and to the semiconductor body and configured to abut the first mobile structure in the direction. means for capacitively detecting said oscillations of said first mobile structure; and at least one abutment element, wherein said elastic assembly is configured to enable said oscillations of said first mobile structure as a function of a force applied in said direction to said first mobile structure, and wherein said first mobile structure, said abutment element and said elastic assembly are arranged with respect to each other in such a way that: when said force applied to said first mobile structure is lower than an abutment force threshold, then said first mobile structure is not in contact with said abutment element and said elastic assembly operates with a first elastic constant; and when said force applied to said first mobile structure is greater than said abutment force threshold, then said first mobile structure is in contact with said abutment element and generates, under the action of the applied force, a deformation of said elastic assembly such that said elastic assembly operates with a second elastic constant different from said first elastic constant; wherein said elastic assembly comprises a first spring and a second spring having a third elastic constant greater than said first elastic constant, said first mobile structure being mechanically coupled to said semiconductor body via said first spring and said second mobile structure being mechanically coupled to said semiconductor body via said second spring.

21. The micro-mechanical device according to claim 20, wherein the capacitive detection means comprise: at least one mobile electrode adapted to be biased at a first voltage, configured to oscillate together with said first mobile structure; and at least two fixed electrodes adapted to be biased at a second voltage, and wherein said at least one mobile electrode extends between said at least two fixed electrodes and is capacitively coupled to said at least two fixed electrodes to form two respective capacitors having a variable capacitance.

22. The micro-mechanical device according to claim 21, wherein said at least one mobile electrode is fixed with respect to said first mobile structure and said at least two fixed electrodes are fixed with respect to a substrate.

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