Microelectromechanical sensor with external fluid coupling including contamination reduction structure

Abstract

Embodiments of the present disclosure relate to a microelectromechanical sensor having external fluid coupling including a contamination reduction structure. The micro-electro-mechanical sensor includes: a support including a semiconductor material; and a cover of semiconductor material, the cover coupled to the support and having an inner surface disposed facing the support, and a plurality of inlet holes. The sensor further comprises a sensing structure comprising a measurement chamber and a sensitive element, the sensitive element being at least partially formed in the support and facing the measurement chamber; a fluid path configured to couple the sensing structure with an environment external to the sensor through the inlet aperture, and having an access section to the measurement chamber; and a capture structure defined in the support body. The capture structure is in communication with a respective fluid path and extends at least partially in the support body at a greater distance from the inner surface of the cover relative to the entry section of each fluid path.

Description

Technical Field

[0001] The present disclosure relates to a micro-electromechanical sensor having an external fluid coupling with a contamination reduction structure. Background Art

[0002] Environmental quantity sensors, such as MEMS (micro-electromechanical) air pressure sensors, humidity sensors and chemical detectors and sensors, typically comprise a sensing element which is enclosed in a housing and connected to the external environment by means of one or more inlet holes and internal fluid paths in the housing to receive the quantity to be measured. For example, in a MEMS pressure sensor, the sensing element is typically defined by a membrane which deforms in response to changes in external pressure: in this case, the pressure signal can be read capacitively or resistively relative to an (internal) reference pressure. The inlet holes and internal fluid paths allow external pressure changes to propagate to the sensing element.

[0003] However, in addition to ensuring fluid coupling with the outside, the inlet hole can also allow potentially harmful particles, such as dust particles, to reach the sensing element of the sensor via the internal fluid path. Polluting particles may affect the function of the sensor, for example by changing the capacitance between the conductive paths and / or creating drift of the sensing element.

[0004] To overcome the problem of particle contamination, specially designed inlet holes are often used, both in terms of location (e.g., at a sufficient distance from the sensing element) and in terms of number and size. However, there are constraints that may limit the effectiveness of such measures. For example, reducing the number of inlet holes may be incompatible with the ideal redundancy for this type of sensor, while too small a size may more easily lead to clogging of the inlet holes, both due to the characteristics of current manufacturing processes and due to the high likelihood of particle accumulation. Summary of the invention

[0005] Various embodiments of the present disclosure overcome or at least partially alleviate the disadvantages and limitations of the prior art.

[0006] According to the present disclosure, a micro-electromechanical sensor with external fluid coupling is proposed. The micro-electromechanical sensor includes: a support body, the support body includes a semiconductor material; and a cover (cap) of the semiconductor material, the cover is coupled to the support body and has an inner surface arranged facing the support body, and a plurality of inlet holes. The sensor also includes a sensing structure, the sensing structure includes a measuring chamber and a sensitive element, the sensitive element is at least partially formed in the support body and faces the measuring chamber; a fluid path, the fluid path is configured to couple the sensing structure with the environment outside the sensor through the inlet hole, and has an access section to the measuring chamber; and a capture structure defined in the support body. The capture structure is connected to the corresponding fluid path and extends at least partially in the support body at a greater distance from the inner surface of the cover relative to the access section of each fluid path. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] For a better understanding of the present disclosure, reference is made to the accompanying drawings, in which various embodiments are presented by way of non-limiting examples, in which:

[0008] Figure 1 A MEMS sensor according to an embodiment of the present disclosure is schematically shown in cross section;

[0009] Figure 2 The top view schematically shows Figure 1 MEMS sensors;

[0010] Figure 3a and Figure 3b Schematically shows Figure 1 Successive steps of the manufacturing process of a MEMS sensor;

[0011] Figure 4 A MEMS sensor according to various embodiments of the present disclosure is schematically shown in cross section;

[0012] Figure 5 The top view schematically shows Figure 4 MEMS sensors;

[0013] Figure 6 The top view schematically shows Figure 4 an enlarged portion of a MEMS sensor; and

[0014] Figures 7a to 7c Schematically shows Figure 4 Successive steps of the MEMS sensor manufacturing process. DETAILED DESCRIPTION

[0015] The following description refers to the arrangements shown in the accompanying drawings; therefore, expressions such as "above", "below", "upper", "lower", "top", "bottom", "right", "left", etc. relate to the accompanying drawings and are not to be interpreted in a limiting manner.

[0016] Figure 1 and Figure 2 A portion of a microelectromechanical (MEMS) sensor with external fluid coupling, such as an air pressure sensor (or simply a pressure sensor), is illustrated according to an embodiment of the present disclosure and is indicated as a whole using the reference numeral 1. The pressure sensor 1 includes a support body 2, which contains a semiconductor material (such as intrinsic and / or doped silicon); and a cover 3, which is also a semiconductor material. The cover 3 covers the support body 2 and has an inner surface 3a arranged facing the support body 2. The cover 3 is also bonded to the support body 2 by a bonding ring 4. The thickness of the bonding ring determines the distance between the cover 3 and the support body 2. Considering the reference system of orthogonal axes X, Y, and Z, the support body 2 and the cover 3 have a substantially planar shape parallel to the XY plane and are stacked in the direction of the Z axis.

[0017] The support body 2 accommodates a sensing structure 6 which occupies a substantially central position in the pressure sensor 1. The sensing structure 6 communicates with the environment outside the pressure sensor 1 via a plurality of inlet holes 5, also called ventilation holes or "chimneys", which are arranged, for example, along at least one lateral region of the pressure sensor 1.

[0018] The inlet holes 5 are through holes that pass through the cover 3 and are in direct communication with the environment outside the pressure sensor 1. In a non-limiting embodiment, the inlet holes 5 have a circular cross section and are organized in two rows parallel to the Y axis. In practice, the support 2, the cover 3 and the keying ring 4 define a volume accessible from the outside through the inlet holes 5, which allows the external pressure P EXT (e.g. atmospheric pressure) and / or other physical parameters (such as, for example, humidity) arrive at the support 2.

[0019] In view of the above, the sensing structure 6 is surrounded by two rows of inlet holes 5. The sensing structure 6 specifically comprises: a reference chamber 7, which is permanently sealed relative to the external environment and is maintained at a reference pressure (internal pressure P 0 ) below; a film 8 of semiconductor material, which is arranged above the reference chamber 7; and a measurement chamber 9, which extends above the film 8, on the side opposite to the reference chamber 7, and is fluidically coupled to the external environment. In more detail, the film 8 is inserted between the reference chamber 7 and the measurement chamber 9, and has a lower surface 8a arranged facing the reference chamber 7 and an upper surface 8b arranged facing the measurement chamber 9. The reference chamber 7 is a buried cavity in the support body 2.

[0020] The membrane 8 is for example fixed by an anchor (for simplicity, Figure 1 The membrane 8 (not shown separately) is suspended on the reference chamber 7 so that deformations of the membrane 8 can occur in a direction parallel to the Z axis and therefore perpendicular to the support 2: due to variations in external pressure relative to the pressure in the reference chamber 7, i.e. due to variations in pressure on the upper surface 8b, the membrane 8 is free to deform and the deformations can be read by exploiting electrical phenomena. For example, the membrane 8 is provided with a piezoelectric sensing structure comprising an implanted piezoresistance 7a, which responds to deformations of the same membrane 8. In an alternative embodiment (not shown), the membrane 8, which is electrically conductive and suitably insulated from the support 2, can be capacitively coupled to a reference electrode placed at the base of the reference chamber 7; in this case, a deflection of the lower face 8a of the membrane 8 results in a variation of the capacitive coupling detectable at the external terminals.

[0021] The measuring chamber 9 of the sensing structure 6 is in communication (e.g., fluidly connected) with the environment outside the pressure sensor 1 through the inlet holes 5 and the corresponding fluid paths 10. Specifically, each fluid path 10 is at least partially defined by the support body 2 at the bottom and at least partially defined by the cover 3 at the top, and fluidically connects the measuring chamber 9 with the corresponding row of inlet holes 5.

[0022] The support 2 under each fluid path 10 has a protrusion towards the cover 3, which is made by using a high topography and is called a barrier 11. The barrier 11 has a corresponding top surface, which defines the minimum thickness of each fluid path 10 along the Z axis and starting from the inner surface 3a of the cover 3: this minimum thickness is selected (for example, about 1 μm) so as to reduce the probability of contamination particles (for example, with a size between 0.5 μm and 10 μm) entering the sensing structure 6 without affecting the coupling with the external fluid. In addition, as explained below, the barrier 11 forces any contamination particles to be collected in a dedicated reservoir. The wire 10a for connecting the pressure sensor 1 can be embedded in a container such as Figure 1 The illustrated barrier 11 or extends over the same barrier 11 .

[0023] refer to Figure 1 , the fluid path 10 of the pressure sensor 10 has an entry section 15 to the sensing structure 6 and more specifically to the measuring chamber 9. The entry section 15 is the section of the terminal passage of the fluid path 10 facing the measuring chamber 9. Figure 1 In the example of , the end portion of the fluid path 10 toward the measuring chamber 9 is common and the entry section 15 is also common. In the pressure sensor 1, the entry section 15 is bounded, for example, at the top by the cover 3 and at the bottom by the barrier 11 of the support body 2 and is adjacent to the measuring chamber 9.

[0024] The support body 2 also houses a capture structure 12 configured to locally collect and retain contamination particles from the external environment to the pressure sensor 1. In one embodiment, the capture structure 12 of the pressure sensor 1 is a confinement groove having an elongated shape parallel to the Y axis defined in the support body 2. The capture structures 12 extend in a continuous manner, each capture structure being below a corresponding row of inlet holes 5 and Figure 1 and Figure 2 In the embodiment of FIG. 1 (where two capture structures are shown), the capture structures 12 extend along opposite sides of the sensing structure 6. In a non-limiting embodiment, the capture structures 12 are aligned with corresponding rows of inlet apertures 5 along the Z axis. More generally, the capture structures 12 are defined in the support 2 close to the corresponding inlet apertures 5.

[0025] Each capture structure 12 is in fluid communication with the corresponding inlet hole 5 and the corresponding fluid path 10. In detail, each capture structure 12 is defined along a cross section of the corresponding fluid path 10. Figure 1 Each capture structure 12 has a bottom surface 12 a and forms a collecting reservoir below the corresponding inlet hole 5 and the corresponding fluid path 10 for the contamination particles that enter the pressure sensor 1 through the inlet hole 5 .

[0026] Reference again Figure 1 , the capture structures 12 extend in the support 2 along the Z axis to a greater depth relative to the entry section 15 of the corresponding fluid path 10. In more detail, the bottom surface 12a of each capture structure 12 is at least partially located at a greater depth relative to the corresponding top surface of the barrier 11 and in particular relative to the entry section 15 of the fluid path 10, the greater depth being measured from the inner surface 3a of the cover 3. In a non-limiting embodiment, the bottom surface 12a of each capture structure 12 is additionally located at a greater depth relative to the upper surface 8b of the membrane 8. Moreover, each capture structure 12 has a greater dimension transversely to the Z axis relative to the corresponding dimension of the inlet hole 5; more generally, each capture structure 12 has a section that promotes the accumulation of contaminants. The fluid path 1 of the pressure sensor 10 thus exhibits a high resistance to the passage of contaminating particles, while the capture structures 12 exhibit a high ability to retain them.

[0027] Therefore, in the MEMS pressure sensor of the present disclosure, contamination particles from the external environment tend to accumulate in the capture structure and are hindered in their possible travel through the fluid path toward the sensing structure. In the pressure sensor, the probability of contamination particles depositing near the membrane is thus significantly reduced, thereby limiting the changes in electromechanical parameters during the life of the sensor. The pressure sensor of the present disclosure ultimately has more reliable measurement performance and repeatability.

[0028] The capture structure 12 can be formed in the manufacturing process of the pressure sensor 1, at a step after the support body 2 is formed and patterned, such as Figure 3a and Figure 3b Reference Figure 3a In a working wafer 100 including a support body 2 of a pressure sensor 1, a buried cavity corresponding to a reference chamber 7 is first created according to techniques known in the industry (for example, by using a sacrificial layer that is removed after the formation of the upper semiconductor layer, releasing the area corresponding to the buried cavity); the membrane 8, the conductive line 10a, the implanted piezoresistors 7a and the barrier 11 are then defined.

[0029] Afterwards ( Figure 3b ), using a specific trench mask not shown, the capture structure 12 of the pressure sensor 1 is formed by using, for example, anisotropic etching. This anisotropic etching can be divided into consecutive and mutually different steps; for example, time etching and / or etching with different etching chemical compositions can be used depending on the depth and width of the trench to be formed and the material to be removed in the support 2.

[0030] The cover 3 is then bonded to the support 2 by means of the bonding ring 4; the inlet holes 5 are finally formed, for example in a manner vertically aligned with the corresponding capture structures 12 and by using selective etching, so as to obtain Figure 1 and Figure 2 Pressure sensor 1.

[0031] Figure 4 and Figure 5 Parts of a MEMS air pressure sensor (or simply referred to as a pressure sensor) according to various embodiments of the present disclosure are illustrated, and the MEMS air pressure sensor is generally indicated using reference numeral 50 . Figure 4 and Figure 5 in Figure 1 and Figure 2 Elements corresponding to those of are illustrated using the same reference numerals. Furthermore, the pressure sensor 50 is described below with reference to the differences relative to the pressure sensor 1 .

[0032] The pressure sensor 50 includes a platform (also referred to as a "decoupling mass") 70 that at least partially accommodates the sensing structure 6. The platform 70 is formed by a flexure (at Figure 4 and Figure 5The support 2 is suspended relative to the support 2 (not shown) and is separated from the support 2 by a separation region 75. In a non-limiting embodiment, the separation region 75 is a groove surrounding the platform 70 and has a substantially spiral shape in a section along a plane parallel to the XY plane. A first portion 75a of the separation region 75 extends below the entire dimension of the platform 70 and at least extends to the entire dimension of the platform 70. A second portion 75b of the separation region 75 extends transversely to the first portion 75a (here parallel to the Z axis) and communicates with the first portion 75a.

[0033] In the pressure sensor 50 , the platform 70 improves the suppression of thermomechanical stresses caused, for example, by a packaging step and / or a soldering step of the pressure sensor.

[0034] The measuring chamber 9 of the sensing structure 6 communicates with the environment outside the pressure sensor 50 through the inlet holes 5 and the corresponding fluid paths 60. In detail, each fluid path 60 of the pressure sensor 50 is buried in the support body 2 at least for a cross section and connects the measuring chamber 9 with the corresponding row of inlet holes 5 from the fluid point of view. In one embodiment, the second part 75b of the separation area 75 defines a common part of the fluid paths 60. In this embodiment, the keying ring 4 includes an internal element 4a surrounding the platform 70: the presence of the internal element 4a causes the measuring chamber 9 to be coupled to the outside to receive the pressure P through the fluid path passing through the support body 2 as described above. EXT .

[0035] refer to Figure 4 , the fluid path 60 of the pressure sensor 50 has an entry section 65 to the sensing structure 6 and more specifically to the measuring chamber 9. The entry section 65 is a cross section of the terminal passage of the section of the fluid path 60 corresponding to the second portion 75b of the separation region 75. Figure 4 In the example of , the end portion of the fluid path 60 facing the measuring chamber 9 is common and the entry section 65 is also common, the entry section 65 having the spiral shape of the separation area 75 in the section along the plane parallel to the XY plane (the entry section 65 is actually the section of the separation area 75 in the plane parallel to the XY plane at the level of the upper surface 8b of the membrane 8 and facing the measuring chamber 9). In other words, the fluid path 60 is connected to the measuring chamber 9 via the corresponding entry section 65.

[0036] The support body 2 of the pressure sensor 50 also accommodates a capture structure 62, which is configured to locally collect and retain contamination particles from the external environment. In detail, the capture structures 62 of the pressure sensor 50 are defined in the support body 2 and each capture structure includes a groove portion 63 and a connection portion 64 that are connected to each other. In addition, the capture structure 62 is defined near the corresponding inlet hole 5.

[0037] The groove portion 63 of each capture structure 62 has an elongated shape parallel to the Y-axis and extends in a continuous manner below the corresponding row of inlet holes 5 (e.g., vertically offset relative to the corresponding row of inlet holes 5). Figure 4 and Figure 5 , the groove portions 63 (two groove portions are shown in the figure) of the capture structure 62 extend along opposite sides of the sensing structure 62. In the section, the groove portions 63 extend parallel to the Z axis, each groove portion being interposed between a corresponding row of inlet holes 5 and a corresponding fluid path 60.

[0038] The connection portion 64 of each capture structure 62 is at least partially defined in the corresponding fluid path 60. In detail, each connection portion 64 extends between the corresponding groove portion 63 and the separation area 75 and includes a capture piece extending downward. In a non-limiting embodiment, the bottom surface 63a of the groove portion 63 and the bottom surface 64a of the connection portion 64 are located at the same depth relative to a reference plane (e.g., relative to the inner surface 3a of the cover 3). However, it is understood that the bottom surfaces 63a, 64a may be located at different depths depending on the type of groove formed in the support body 2 (see the details of the manufacturing process below).

[0039] In view of the above, each capture structure 62 is in fluid communication with the corresponding inlet hole 5 and the corresponding fluid path 60. Figure 4 Each capture structure 62 is formed below the corresponding inlet hole 5 and the corresponding fluid path 60 to collect the reservoir for the contamination particles that enter the pressure sensor 50 through the inlet hole 5.

[0040] Reference again Figure 4 , each capture structure 62 extends at least partially along the Z axis and to a greater depth starting from the cover 3 relative to each entry section 65 of the corresponding fluid path 60. In more detail, the bottom surface 63a, 64a of each capture structure 62 is at least partially located at a greater depth measured from the inner surface 3a of the cover 3 relative to the upper surface 8b of the membrane 8 and therefore also relative to the entry section 65. In addition, the groove portion 63 of the capture structure 62 has a greater width along the X axis relative to the diameter of the inlet hole 5; more generally, each capture structure 62 presents a section that facilitates the accumulation of contaminants. The fluid path 60 of the pressure sensor 50 therefore shows a high resistance to the passage of contaminant particles, while the capture structure 62 shows a high ability to retain contaminant particles.

[0041] refer to Figure 6, the fluid path 60 of the pressure sensor 50 and in particular the connection portion 64 of the capture structure 62 can be formed in the support 2 and develop along a tortuous path parallel to the XY plane. For example, in one embodiment, the connection portion 64 of the capture structure 62 has an elbow 64b and a blind branch 64c. Such a fluid coupling of the sensing structure 6 with the inlet hole 5 makes the insulation of the membrane 8 more robust with respect to particle contamination: in fact, the membrane 8 further reduces the probability of reaching the sensitive element of the pressure sensor.

[0042] During the manufacturing process of the pressure sensor 50, when the platform 70 is defined by the open separation area 75, the capture structure 62 can be formed, such as in Figures 7a to 7c Reference Figure 7a , the working wafer 150 including the support 2 of the pressure sensor 50 is first processed to create the buried cavity 80 and the connection part 64 of the capture structure 62 by an etching step, epitaxial growth and annealing, not shown. Specifically, in the etching step, the connection part 64 and the structure separated by the trench (such as a wall or a column) in the area corresponding to the buried cavity 80 can be defined. During the epitaxial growth, the trench is closed without being filled, and during the annealing, the silicon is redistributed to form the buried cavity 80. Subsequently ( Figure 7b ), as previously described, the reference chamber 7, the membrane 8, the conductive wire 10a and the implanted piezoresistance 7a are formed.

[0043] Therefore, reference Figure 7c , using a specific mask (not shown), the working wafer 150 is selectively etched (e.g., by anisotropic etching) at least up to the buried cavity 80 and the connection portion 64 of the capture structure 62 to define the first portion 75b, the second portion 75b of the separation region 75 and the elastic element that keeps the platform 70 suspended relative to the support 2, thereby releasing the platform 70. At the same time and without using other masks or steps, the capture structure 62 of the pressure sensor 50 and in particular the groove portion 63 is formed.

[0044] The cover 3 is then bonded to the support 2 by means of a bonding ring 4; the inlet hole 5 is finally formed, for example by using selective etching, so as to obtain Figure 4 and Figure 5 The pressure sensor 50 is provided.

[0045] Finally, it is obvious that modifications and variations may be made to what has been described and illustrated herein without thereby departing from the scope of the present disclosure.

[0046] For example, the sensing structure may include more than one piezoelectric membrane and / or elements sensitive to pressure changes having properties different from those shown. More generally, the sensing structure may be different and may be able to sense different physical quantities, such as for example humidity.

[0047] Furthermore, the inlet holes of the pressure sensor may differ from what is shown and may, for example, have a different geometry and / or be organized in a different number and / or in a different geometric arrangement in the cover: the inlet holes may, for example, be organized in three rows which surround the sensing structure on three different sides.

[0048] Still achieving the function of fluid communication between the inlet hole and the sensing structure, the fluid path can be different from that previously described, for example, the fluid path can be formed to have a geometry that is different in cross-section and top view from the geometry shown in the drawings.

[0049] Regarding the capture structure, depending on the desired degree of contaminant accumulation, the trench can be formed with a geometry that can differ in cross section from the geometry shown. Alternatively, the trench can surround the sensing structure even in areas of the pressure sensor where no inlet hole is present.

[0050] In a variant not shown, the sensing structure is formed on the platform, but the fluidic coupling between the inlet hole and the measuring chamber also or only occurs via the fluid path defined by the cover and the support; in such a variant, the capture structure can be characterized, for example, by the absence of connecting parts.

[0051] The micro-electromechanical sensor (1; 50) can be summarized as comprising: a support (2), the support (2) comprising a semiconductor material; a cover (3) of the semiconductor material, the cover (3) being bonded to the support (2) and having an inner surface (3a) arranged facing the support (2), and a plurality of inlet holes (5); a sensing structure (6), the sensing structure (6) comprising a measuring chamber (9) and a sensitive element (8), the sensitive element (8) being at least partially formed in the support (2) and facing the measuring chamber (9); a fluid path (10; 60), the fluid path (10 ; 60) is configured to couple the sensing structure (6) to the environment outside the sensor through an inlet hole (5) and has an entry section (15; 65) to the measuring chamber (9); a capture structure (12; 62), the capture structure (12; 62) is defined in the support body (2), wherein the capture structure (12; 62) is connected to the corresponding fluid path (10; 60) and extends at least partially in the support body (2) at a greater distance from the inner surface (3a) of the cover (3) relative to the entry section (15; 65) of each fluid path (10; 60).

[0052] The inlet apertures (5) are organized into rows which surround the sensing structure (6) on opposite sides.

[0053] The capture structure (12) comprises a groove extending in the support body (2) in vertical alignment with the corresponding inlet aperture (5).

[0054] The fluid path (10) is at least partially defined by the support (2) and the cover (3) and may be interposed between the respective inlet aperture (5) and the sensing structure (6).

[0055] Capture structures (12) are defined along sections of corresponding fluid pathways (10).

[0056] The sensor (50) further comprises a platform (70) which is suspended relative to the support (2) and in which the sensing structure (6) is at least partially formed.

[0057] Each of the capture structures (62) includes a groove portion (63) and a connecting portion (64), the groove portion (63) and the connecting portion (64) being connected to each other; and the groove portion (63) extends in the support body (2), and the connecting portion (64) is inserted between the corresponding groove portion (63) and the platform (70).

[0058] The fluid paths (60) are at least partially defined in the support (2), and each fluid path is inserted between the corresponding inlet hole (5) and the sensing structure (6), and each connecting portion (64) of the capture structure (62) is at least partially defined in the corresponding fluid path (60).

[0059] The fluid path (60) evolves along a tortuous path in a plane (XY) parallel to the inner surface (3a) of the cover (3).

[0060] The fluid path (60) has an elbow (64b) and a blind branch (64c).

[0061] The sensing structure (6) is sensitive to pressure changes in the environment outside the sensor and comprises a reference chamber (7), and wherein the sensitive element comprises a membrane (8) which is interposed between the reference chamber (7) and a measuring chamber (9); the reference chamber (7) is a buried cavity in the support (2), and the measuring chamber (9) is delimited by the support (2) and the cover (3) and is coupled to the environmental fluid outside the sensor.

[0062] Each capture structure (12; 62) has a respective bottom surface (12a; 63a, 64a) at a greater distance from the inner surface (3a) of the cover (3a) relative to the membrane (8) of the sensing structure (6).

[0063] The process for manufacturing a micro-electromechanical sensor (1; 50) can be summarized as comprising: in a support (2) comprising a semiconductor material, defining: a sensing structure (6), the sensing structure (6) comprising a measuring chamber (9) and a sensitive element (8) facing the measuring chamber (9); a fluid path (10; 60), the fluid path (10; 60) having an entry section (15; 65) to the measuring chamber (9); and a capture structure (12; 62) communicating with the corresponding fluid path (10; 60); placing the semiconductor A covering (3) of a material is bonded to a support (2), the covering (3) having an inner surface (3a) arranged facing the support (2); a plurality of inlet holes (5) are formed in the covering (3), the plurality of inlet holes (5) being fluidically connected to corresponding fluid paths (10; 60); wherein a capture structure (12; 62) extends at least partially in the support (2) at a greater distance from the inner surface (3a) of the covering (3) relative to an entry section (15; 65) of each fluid path (10; 60).

[0064] Defining the sensing structure (6) includes forming a platform (70) suspended relative to a support (2), wherein forming the platform (70) includes: forming a buried cavity (80) and a portion (64) of a fluid path (60) in the support (2); and selectively etching the support (2) at least up to the buried cavity (80) to release the platform (70), and each capture structure (62) is at least partially defined in a corresponding fluid path (60).

[0065] The various embodiments described above can be combined to provide further embodiments.

[0066] These and other changes can be made to the embodiments in light of the above detailed description. In general, in the appended claims, the terms used should not be interpreted 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 range of equivalents to which such claims are entitled. Therefore, the claims are not limited by this disclosure.

Claims

1. A micro-electromechanical sensor, comprising: a support body, the support body comprising a semiconductor material; a cover, the cover being of a semiconductor material, the cover being bonded to the support, and having an inner surface and a plurality of inlet holes, the inner surface being arranged to face the support; a sensing structure, the sensing structure comprising a measuring chamber and a sensitive element, the sensitive element being at least partially formed in the support body and facing the measuring chamber; a fluid path configured to couple the sensing structure with an environment external to the sensor through the plurality of inlet apertures and having an entry section to the measurement chamber; a capture structure, the capture structure being defined in the support, The capture structure is in communication with respective fluid paths and extends at least partially within the support body at a greater distance from the inner surface of the cover relative to the entry section of each of the fluid paths. 2 . The sensor of claim 1 , wherein the inlet apertures are organized into rows that surround the sensing structure on opposite sides. 3 . The sensor of claim 1 , wherein the capture structure comprises a groove extending in the support body in vertical alignment with the corresponding inlet aperture. 4 . The sensor of claim 1 , wherein the fluid path is at least partially defined by the support and the cover, and is interposed between a corresponding inlet hole and the sensing structure.

5. The sensor of claim 1, wherein the capture structures are defined along respective segments of the fluid paths.

6. The sensor according to claim 1, further comprising: A platform is suspended relative to the support, the sensing structure being at least partially formed in the platform.

7. The sensor according to claim 6, wherein the capture structures each include a groove portion and a connection portion, the groove portion and the connection portion being in communication with each other; and The groove portions extend in the support body, and the connecting portions are interposed between the corresponding groove portions and the platform.

8. The sensor according to claim 7, wherein the fluid paths are at least partially defined in the support body, and each of the fluid paths is interposed between a corresponding inlet aperture and the sensing structure, and Each connection portion of the capture structure is at least partially defined within a corresponding fluid path.

9. The sensor of any one of claims 6, wherein the fluid path follows a tortuous path in a plane parallel to the inner surface of the cover.

10. The sensor of any one of claims 6, wherein the fluid path has elbows and blind branches.

11. The sensor according to claim 1, wherein the sensing structure is sensitive to pressure changes in the environment external to the sensor and includes a reference chamber, wherein the sensitive element comprises a membrane, the membrane being interposed between the reference chamber and the measuring chamber, The reference chamber comprises a buried cavity in the support body, and the measurement chamber is delimited by the support body and the cover and is coupled to the ambient fluid outside the sensor.

12. The sensor of claim 11, wherein each of the capture structures has a bottom surface that is at a greater distance from the inner surface of the cover relative to the membrane of the sensitive element.

13. A method for manufacturing a micro-electromechanical sensor, the method comprising: In a support comprising a semiconductor material, it is defined that: A sensing structure, the sensing structure comprising a measuring chamber and a sensitive element, the sensitive element facing the measuring chamber; a fluid path having an access section to the measurement chamber; as well as a capture structure in communication with a corresponding fluid path; bonding a cover of semiconductor material to the support, the cover having an inner surface arranged to face the support; forming a plurality of inlet apertures in the cover, the plurality of inlet apertures being in fluid communication with respective fluid paths; wherein the capture structure extends at least partially in the support body at a greater distance from the inner surface of the cover relative to the entry section of each of the fluid paths.

14. The method according to claim 13, The sensing structure is defined as comprising: forming a platform, the platform being suspended relative to the support, and Wherein forming the platform comprises: forming a buried cavity and a portion of the fluid path in the support body; and The support body is selectively etched at least down to the buried cavity to release the platform, the capture structures each being at least partially defined in a respective fluid path.

15. A device comprising: Support body; a cover coupled to the support, the cover comprising a plurality of inlet apertures; A sensing structure, the sensing structure is on the supporting body, and the sensing structure comprises: a sensitive element in the support body; and a measuring chamber positioned between the sensitive element and the cover; a fluid path fluidically coupling the sensing structure to the plurality of inlet apertures; and A capture structure is provided in the support body, each of the plurality of inlet apertures covering at least one of the capture structures.

16. The device of claim 15, wherein a first entrance hole among the plurality of entrance holes covers a first capture structure of the capture structure, a second entrance hole among the plurality of entrance holes covers a second capture structure of the capture structure, and the first capture structure is separated from the second capture structure by the sensing structure.

17. The device of claim 15, wherein the sensing structure is separated from the capture structure by the fluid path.

18. The device according to claim 15, further comprising: A plurality of blocking members extend from the support body toward the covering member, and the fluid path covers the plurality of blocking members.

19. The device of claim 15, wherein each of the trapping structures comprises a trench extending into the support body.

20. The device of claim 15, wherein the sensing structure comprises a suspended platform, the sensitive element being within the suspended platform.

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