Pressure sensor with high detection performance and optimized manufacturing

Abstract

The invention relates to a pressure sensor with high detection performance and optimized manufacturing. A pressure sensor includes a substrate, a deformable detection element suspended on the substrate, and an anchor structure configured to support the deformable detection element over the substrate. The deformable detection element extends in a first direction at a distance from the substrate and is deformable in accordance with a pressure to be detected. The anchoring structure includes anchoring portions extending from the substrate, coupled to the deformable detection element, and arranged at a distance from each other along a second direction transverse to the first direction. A structural region of the anchoring structure extends between the anchoring portions along a second direction and includes at least one release opening extending through the structural region.

Description

Cross-references to related applications

[0001] This application claims priority to Italian Patent Application No. 102024000024015, filed on October 28, 2024, the entire contents of which are incorporated herein by reference to the fullest extent permitted by law. Technical Field

[0002] This invention relates to a pressure sensor, particularly a microelectromechanical system (MEMS) type pressure sensor, which has high detection performance and optimized manufacturing. Background Technology

[0003] MEMS pressure sensors are known to have a membrane configured to deform according to the external pressure to be measured. By detecting the deformation of the membrane (e.g., by capacitance detection), the measurement result of the external pressure can be obtained.

[0004] Figure 1 An example of a MEMS pressure sensor 1 in a Cartesian coordinate system XYZ is shown. The sensor includes a substrate 3 formed by a semiconductor layer 4, an insulating layer 5 on the semiconductor layer 4, and a conductive layer 6 on the insulating layer 5.

[0005] A semiconductor material film 7 is suspended on the substrate 3 at a distance from the conductive layer 6 along the Z-axis.

[0006] The membrane 7 is supported by an anchoring structure 9, which extends from the substrate 3 along the Z-axis and is coupled to the membrane 7.

[0007] The membrane 7 faces the conductive layer 6 along the Z-axis, and the buried cavity 10 extends between the membrane 7 and the conductive layer 6.

[0008] The cavity 10 is sealed to the outside, that is, it is hermetically separated from the area of ​​the pressure sensor 1 that extends above the membrane 7 and is under the external pressure to be detected. In this way, the membrane 7 deforms according to the difference between the external pressure to be detected and the pressure in the cavity.

[0009] The pressure sensor 1 also includes a release opening 12 that extends along the Z-axis through the membrane 7 over its entire thickness. The release opening 12 allows for the fabrication of the embedded cavity 10.

[0010] The sealing area 13 of the insulating material extends over the release opening 12 and is configured to seal the release opening 12 to maintain the airtightness of the sealed cavity 10.

[0011] In fact, as Figures 2A-2C As shown in detail, the method for forming the buried cavity 10 envisions forming a sacrificial layer 15 made of an oxide material. Figure 2A ), forming a release opening 12 ( Figure 2B ), and chemical etching is performed by releasing opening 12 ( Figure 2C (As shown by the middle arrow 16) to remove the sacrificial layer 15.

[0012] The presence of the release opening 12, which passes through the membrane 7 and is therefore close to the sacrificial layer 15, allows for accelerated release. Figure 2C The removal step of the sacrificial layer 15.

[0013] However, the presence of the sealing region 13 in contact with the membrane 7 may generate residual mechanical stress in the membrane 7 (e.g., caused by the difference in the coefficient of thermal expansion between the membrane 7 and the sealing region 13), and may therefore alter the elastic deformation behavior of the membrane 7.

[0014] Therefore, the detection performance of pressure sensor 1 is low.

[0015] The need to overcome in this field Figure 1 and Figures 2A-2C The shortcomings of its implementation. Summary of the Invention

[0016] According to the present invention, a pressure sensor and a manufacturing method are provided.

[0017] In one embodiment, a pressure sensor includes: a substrate; a deformable sensing element suspended on the substrate, extending a distance from the substrate along a first direction and configured to deform according to a pressure to be detected; and an anchoring structure configured to support the deformable sensing element on the substrate. The anchoring structure includes: a plurality of anchor portions extending from the substrate, coupled to the deformable sensing element, and arranged spaced apart from each other along a second direction transverse to the first direction; and a structural region extending along the second direction between the anchor portions and having at least one release opening.

[0018] In one embodiment, a method of manufacturing a pressure sensor includes: forming a deformable sensing element from a wafer, the deformable sensing element being suspended on the wafer, extending a distance from the wafer along a first direction, and configured to deform according to a pressure to be detected; and forming an anchoring structure configured to support the deformable sensing element on a substrate. Forming the anchoring structure includes: forming a plurality of anchor portions extending from the wafer, coupled to the deformable sensing element, and arranged a distance apart from each other along a second direction transverse to the first direction; and forming a structural region extending along the second direction between the anchor portions and having at least one release opening. Attached Figure Description

[0019] To better understand the invention, embodiments thereof are now described with reference to the accompanying drawings, which are purely non-limiting examples, in which:

[0020] Figure 1 A cross-section of a MEMS pressure sensor is shown.

[0021] Figures 2A-2C It shows Figure 1 The continuous manufacturing steps of MEMS pressure sensors;

[0022] Figure 3 A top view of the MEMS pressure sensor is shown.

[0023] Figure 4 It shows Figure 3 MEMS pressure sensor along Figure 3 The cross section of section line IV-IV;

[0024] Figure 5 It shows Figure 3 A top view of the magnified section of the MEMS pressure sensor;

[0025] Figure 6 It shows Figure 3 A portion of the MEMS pressure sensor along Figure 5 The cross section of section line VI-VI;

[0026] Figure 7 It shows Figure 3 A portion of the MEMS pressure sensor along Figure 5 The cross section of section line VII-VII;

[0027] Figure 8 It shows Figure 3 A portion of the MEMS pressure sensor along Figure 5 The cross section of section line VIII-VIII;

[0028] Figure 9A , Figure 10A , Figure 11A , Figure 12A It shows the relationship with Figure 3 pressure sensor Figure 7 Some related sequential manufacturing steps; and

[0029] Figure 9B , Figure 10B , Figure 11B , Figure 12B It shows the relationship with Figure 3 pressure sensor Figure 8 Some related sequential manufacturing steps. Detailed Implementation

[0030] The following description refers to the arrangement shown in the accompanying drawings; therefore, expressions such as “above,” “below,” “lower,” “upper,” “right,” “left,” “top,” and “bottom” are related to the drawings and should not be interpreted in a restrictive manner.

[0031] Figure 3 and Figure 4 The pressure sensor 30 (hereinafter also referred to as sensor 30) is shown in a Cartesian coordinate system XYZ, which has an X-axis, a Y-axis and a Z-axis.

[0032] Sensor 30 is of the microelectromechanical system (MEMS) type.

[0033] The sensor 30 can be manufactured using microprocessor and nanoprocessor techniques, for example, starting with a semiconductor material wafer, particularly a wafer made of silicon, and a series of processing steps, such as photolithography, chemical etching, growth, annealing, dicing, bonding, etc.

[0034] Sensor 30 is a capacitive sensor.

[0035] The sensor 30 includes a substrate 31, which can be obtained by cutting a wafer of semiconductor material.

[0036] In detail, the substrate 31 includes a semiconductor layer 33 made of a semiconductor material (e.g., made of silicon); an insulating layer 34 made of an insulating or dielectric material (e.g., made of silicon oxide) extending over the semiconductor layer 33; and a conductive layer 35 made, in particular, of a suitably doped semiconductor material (e.g., made of polycrystalline silicon) extending over the insulating layer 34.

[0037] Depending on the specific layout of the sensor 30 and the specific manufacturing process used, the insulating layer 34 may be stacked entirely or partially on the semiconductor layer 33, and the conductive layer 35 may be stacked entirely or partially on the insulating layer 34.

[0038] The sensor 30 includes a detection membrane 38 suspended on a substrate 31 and spaced a distance from the substrate 31 along the Z-axis; and an anchoring structure 40 configured to support the detection membrane 38 on the substrate 31.

[0039] The detection film 38 may be made wholly or partially of a semiconductor material appropriately doped according to the specific application, particularly silicon or polycrystalline silicon.

[0040] In practice, the detection film 38 faces the conductive layer 35 at a distance and is configured to be capacitively coupled to the conductive layer 35. In other words, the detection film 38 forms the upper electrode, and the portion of the conductive layer 35 facing the detection film 38 forms the lower electrode capacitively coupled to the upper electrode.

[0041] The detection membrane 38 is configured to deform (along the Z-axis in the illustrated embodiment) according to the external pressure to be detected.

[0042] Specifically, the sensor 30 also includes a buried cavity 42 extending between the detection film 38 and the substrate 31. In particular, in Figure 4 In one embodiment, the cavity 42 extends below the detection membrane 38.

[0043] The cavity 42 is sealed relative to the area 43 of the sensor 30 exposed to the external pressure to be detected; that is, in Figure 4 In one embodiment, region 43 is arranged above the detection membrane 38, on the opposite side of the buried cavity 42 relative to the reference membrane 38.

[0044] The detection membrane 38 is configured to undergo deformation along the Z-axis, which is a function of the difference between the external pressure to be detected (above the detection membrane 38) and the pressure in the embedded cavity 42 (below the detection membrane 38).

[0045] In detail, during the design phase, the dimensions of the detection membrane 38 (surface area on the XY plane and thickness along the Z axis) can be adjusted according to the desired detection characteristics.

[0046] Specifically, refer to Figure 3 The plan view shows that the detection membrane 38 has a horizontal width D. x (Measured parallel to the X-axis) and vertical width D y (Measured parallel to the Y-axis). In Figure 3 In the embodiments described, the detection membrane has a rectangular shape in the top view, and D x <D y Therefore, the horizontal width D x It can be defined as the characteristic size of the detection membrane 38.

[0047] The following will refer to Figures 5-8 Detailed description of anchoring structure 40, Figures 5-8 An enlarged portion 45 of the anchoring structure 40 is shown.

[0048] Anchoring structure 40 extends around detection membrane 38.

[0049] In detail, the anchoring structure 40 defines the detection membrane 38 and its corresponding dimension D. x D y .

[0050] The anchoring structure 40 has an inner surface 46A adjacent to the detection membrane 38, i.e., facing the interior of the detection membrane 38; and an outer surface 46B opposite to the inner surface 46A.

[0051] In practice, the inner surface 46A defines the perimeter of the detection membrane 38.

[0052] The inner surface 46A and the outer surface 46B extend around the detection membrane 38 to at least partially surround the detection membrane.

[0053] To make it clear, Figure 3 and Figures 5-8 In the middle, the inner surface 46A and the outer surface 46B of the anchoring structure 40 are indicated by dashed lines.

[0054] In detail, the anchoring structure 40 includes multiple anchoring portions 50 and a structural region formed by multiple structural portions 51.

[0055] Anchor portions 50 extend from substrate 31, and in particular each anchor portion extends along a corresponding direction parallel to the Z-axis and is coupled to reference film 38.

[0056] In detail, the anchoring portion 50 is fixed to the substrate 31 and the detection film 38; specifically, it has a first end fixed to and in contact with the substrate 31, and a second end opposite to the first end along the Z-axis and fixed to and in contact with the detection film 38.

[0057] Each anchoring portion 50 extends along a corresponding longitudinal axis transverse to the inner surface 46A; specifically, each anchoring portion 50 extends between the inner surface 46A and the outer surface 46B of the anchoring structure 40.

[0058] The width L of the anchoring portion 50 X Along the corresponding longitudinal axis between the inner surface 46A and the outer surface 46B (i.e., reference) Figure 5 The magnified portion (45 along the X-axis) is measured, for example, between 5µm and 30µm.

[0059] Anchoring portion 50 is positioned along a transverse axis transverse to the corresponding longitudinal axis at a distance D. a Arrange each other, that is, refer to Figure 5 45. The magnified portion along the Y-axis.

[0060] For example, distance D a It can be between 1µm and 10µm.

[0061] Each anchoring portion 50 has a width L measured along its respective transverse axis. Y For example, between 0.5µm and 5µm.

[0062] Width L X It can be larger than the width L Y This can improve the support set to the detection membrane 38 and give the anchoring structure 40 higher robustness.

[0063] Width L X Size D of reference film 38 x Dy The ratio between at least one dimension (specifically, width L) X Feature size D of reference film 38 x The ratio between L X / D x It can be greater than 4%, especially between 4% and 20%, and / or the distance D a Size D of reference film 38 x D y The ratio between at least one dimension (specifically, the distance D) a Feature size D of reference film 38 x The ratio between D a / D x The percentage can be less than 8%, particularly between 0.8% and 8%. This relationship can help improve the robustness of the anchoring of the anchoring structure 40 to the detection membrane 38.

[0064] Structural portions 51 each extend between two adjacent anchoring portions 50, specifically parallel to the respective transverse axis (along...). Figure 5 (The Y-axis in the magnified portion).

[0065] In detail, each structural part 51 is suspended on the substrate 31, that is, it is kept at a distance from the substrate 31 along the Z-axis, and is carried by two adjacent anchoring parts 50 parallel to the transverse axis of the anchoring part 50.

[0066] Therefore, structural portion 51 faces along the Z-axis on substrate 31, each located above a corresponding buried cavity in fluid communication with buried cavity 42, and is thus again indicated by 42.

[0067] The structural part 51 also extends between the inner surface 46A and the outer surface 46B of the anchoring structure 40.

[0068] In particular, Figure 5 In one embodiment, each structural portion 51 extends through the width L of the corresponding anchoring portion 50. X Therefore, on the inner surface 46A side, the structural portion 51 is adjacent to the detection membrane 38.

[0069] However, the structural portion 51 can have different widths along the longitudinal axis of the anchoring portion 50, particularly less than the width L. X .

[0070] The structural portion 51 can be formed from the same structural layer used to form the detection membrane 38.

[0071] The structural region 51 includes a plurality of release openings 55, which can be used to fabricate the sensor 30, particularly the embedded cavity 42 and the detection membrane 38. In particular, in the illustrated embodiment, each structural portion 51 includes a corresponding release opening 55.

[0072] Each release opening 55 extends through the thickness of the corresponding structural portion 51 as measured along the Z-axis. In other words, the release opening 55 is a through-hole through the structural portion 51 and is in fluid communication with the underlying embedded cavity 42.

[0073] exist Figure 5 In this context, the release opening 55 is a circular hole; however, depending on the specific layout or manufacturing steps, the release opening 55 can have different shapes, such as polygons (especially rectangles or squares).

[0074] The release opening 55 has a width D measured along a transverse axis (e.g., the Y-axis) between two adjacent anchoring portions 50. o For example, between 0.3µm and 1µm.

[0075] In detail, width D o Less than distance D a This ensures that during manufacturing, the release opening 55 extends over the area forming the cavity 42 to avoid openings in the anchoring portion 50.

[0076] Distance D a With width D o The difference can depend on the misalignment between the photolithographic mask used to form the release opening 55 and the photolithographic mask used to form the anchoring portion 50. Specifically, maintaining D... a -D o A diameter of ≥0.5µm ensures high manufacturing reliability.

[0077] The anchoring structure 40 also includes a plurality of sealing portions 56 configured to seal the release opening 55 and thus seal the buried cavity 42 from the region 43 covered by the reference membrane 38.

[0078] Each sealing portion 56 extends on the corresponding structural portion 51, and extends above and at the corresponding release opening 55.

[0079] The sealing portion 56 may be made of a material different from that of the structural portion 51; in particular, it may be made of a material that can be etched by a class of compounds that are different from those that can be used to chemically etch the structural portion 51.

[0080] For example, the sealing portion 56 may be made of oxides, oxynitrides or nitrides.

[0081] Refer again Figure 3 and Figure 4The sensor 30 may include one or more reference films, which in this embodiment are two reference films 60 and 61.

[0082] Reference membranes 60 and 61 are optional.

[0083] Reference membranes 60 and 61 extend to the sides of the detection membrane 38. In the illustrated embodiment, reference membranes 60 and 61 extend externally along the X-axis to the detection membrane 38, that is, to the left and right sides of the detection membrane 38, respectively.

[0084] Reference films 60 and 61 are suspended on substrate 31 at a distance along the Z-axis and are each supported by a corresponding anchoring structure.

[0085] Specifically, the reference membrane 60 is located on one side of the detection membrane 38. Figure 3 The right side of the detection membrane 38 is supported by a portion of the anchoring structure 40, while the opposite side is supported by a dedicated anchoring area 63. The reference membrane 61 is located on one side of the detection membrane 38. Figure 3 The left side of the detection membrane 38 is supported by a portion of the anchoring structure 40, while the opposite side is supported by a dedicated anchoring area 64.

[0086] The buried cavity 65 extends below the reference film 60 between the reference film 60 and the substrate 31. The buried cavity 66 extends below the reference film 61 between the reference film 61 and the substrate 31.

[0087] The cavities 65 and 66 can be fluidly connected to each other and to the cavity 42; this simplifies the manufacturing of the sensor 30 and reduces the total area occupied by the sensor 30.

[0088] Reference membranes 60 and 61 are configured not to deform under the external pressure to be detected (at least as a first approximation); that is, reference Figure 4 So as not to undergo deformation due to the pressure difference between the region 43 of the upper covering membrane 60, 61 and the lower embedded cavity 65, 66.

[0089] In the illustrated embodiment, the surfaces of the reference films 60 and 61 are smaller than the surface of the detection film 38; specifically, the characteristic dimensions (i.e., the horizontal dimensions measured parallel to the X-axis) of the reference films 60 and 61 can be smaller than the characteristic dimension D of the detection film 38. x .

[0090] Reference membranes 60 and 61 can be used to obtain differential detection of the external pressure to be detected, thereby improving the detection performance of sensor 30.

[0091] Reference membranes 60 and 61 can be formed from the same layers used to form detection membrane 38 and structural portion 51.

[0092] The anchoring regions 63 and 64 of the reference membranes 60 and 61 have a structure similar to that of the anchoring structure 40; in fact, each of the anchoring regions 63 and 64 also includes a corresponding anchoring portion 70, a corresponding structural portion 71, and a corresponding release opening 72.

[0093] Anchoring region 63 has corresponding inner and outer surfaces. The inner surface faces the reference film 60 and forms the peripheral side of the reference film 60. The outer surface is arranged on the opposite side of the inner surface and is spaced a distance from the reference film 60 along the X-axis. Anchoring region 64 has corresponding inner and outer surfaces. The inner surface faces the reference film 61 and forms the peripheral side of the reference film 61. The outer surface is arranged on the opposite side of the inner surface and is spaced a distance from the reference film 61 along the X-axis.

[0094] The descriptions (e.g., dimensions and arrangement) of the anchoring portion 50, structural portion 51 and release opening 55, with necessary modifications to the details, also apply to the anchoring portion 70, structural portion 71 and release opening 72.

[0095] The corresponding sealing portion, not shown here, extends at the release opening 72 onto the structural portion 71 of the anchoring regions 63, 64 to seal the top of the embedded cavities 65, 66.

[0096] The sensor 30 also includes a peripheral sealing element 75 that extends from the substrate 30 around the peripheral side of the sensor 30, i.e. surrounds the films 38, 60, and 61.

[0097] The peripheral sealing element 75 is configured to provide transverse sealing for the cavities 42, 65, and 66.

[0098] In detail, in the illustrated embodiment, the peripheral sealing element 75 is coupled to the anchoring portion 70 of the reference membranes 60, 61.

[0099] Conductive layer 35 includes portions 80, 81, and 82 (composed of...) Figure 3 (as indicated by the dashed lines in the diagram), these portions are defined in the conductive layer 35 through corresponding openings, such as... Figure 4 As shown. Parts 80, 81, and 82 form lower electrodes that are capacitively coupled to the detection film 38, the reference film 60, and the reference film 31, respectively, and also form corresponding connection tracks for coupling with an external detection circuit (not shown here).

[0100] The fact that the release opening 55 is part of the anchoring structure 40 and is arranged between the anchoring portions 50 results in the release opening 55 being located outside the detection membrane 38. In this way, the deformation characteristics of the detection membrane 38 are not affected by the presence of the release opening 55.

[0101] Furthermore, the sealing portion 56 extends without contacting the detection membrane 38; this further helps to ensure the high detection performance of the sensor 30.

[0102] Furthermore, the fact that the release opening is placed within the anchoring structure 40 results in the release opening 55 being positioned closer to the detection membrane 38 and the embedded cavity 42, for example, closer than in the case where the release opening is formed outside the anchoring structure of the membrane; this allows for optimized manufacturing of the sensor 30, as discussed in detail below, and reduces the production cost of the sensor 30.

[0103] In the following description, an embodiment of the manufacturing process of the pressure sensor 30 will be described with reference to steps that will help in understanding the process. However, the manufacturing process may include other steps known to those skilled in the art and therefore will not be described further.

[0104] The fabrication of sensor 30 is described using a portion of the anchoring structure 40 of the reference sensor 30 at the detection membrane 38 as an example; more specifically, regarding... Figure 7 For the part, please refer to Figure 9A , Figure 10A , Figure 11A and Figure 12A ,about Figure 8 For the part, please refer to Figure 9B , Figure 10B , Figure 11B and Figure 12B .

[0105] Figure 9A and Figure 9B A wafer 100 for forming a substrate 31 is shown, the wafer including a semiconductor layer 33, an insulating layer 34 and a conductive layer 35.

[0106] On the conductive layer 35, for example by growth or deposition, there is a lower structural layer 103 (e.g., a semiconductor material such as silicon or polycrystalline silicon) formed; and a sacrificial layer 104, the material of which (e.g., an oxide (especially silicon oxide)) is different from the material of the lower structural layer 103.

[0107] The lower structural layer 103 extends in contact with the conductive layer 35 and is patterned to form the lower part of the anchoring portion 50.

[0108] The lower structural layer 103 can also be patterned to form the lower part of the anchor portion 70 and / or the peripheral sealing element 75.

[0109] The sacrificial layer 104 is used to form the buried cavity 42.

[0110] In this embodiment, the sacrificial layer 104 is also used to form buried cavities 65 and 66.

[0111] Then, the sacrificial layer 104 extends in the regions where it is desired to form the buried cavities 42, 65, and 66.

[0112] The sacrificial layer 104 can be made of a material that can be chemically etched using a different class of compounds than those used to etch the underlying structural layer 103 and / or the conductive layer 35. This ensures greater reliability in the manufacturing process.

[0113] In addition, for example, the upper structural layer 106 is formed by growth or deposition on the lower structural layer 103 and the sacrificial layer 104.

[0114] The upper structural layer 106 can be made of the same material as the lower structural layer 103.

[0115] Specifically, the sacrificial layer 104 may be formed prior to the structural layers 103 and 106, and the structural layers 103 and 106 may be formed together (e.g., deposited or grown) from portions of the conductive layer 35 exposed by the previously patterned overlay sacrificial layer 104 in the same manufacturing step.

[0116] To make it clear, in Figure 9B In the middle, the lower structural layer 103 and the upper structural layer 106 are separated by a dashed line.

[0117] The upper part of the detection membrane 38, the structural part 51, and the anchoring part 50 is formed by the upper structural layer 106.

[0118] The upper and peripheral sealing elements 75 of the reference membranes 60 and 61, structural portion 71, and anchor portion 70 can also be formed from the upper structural layer 106.

[0119] Subsequently, as Figure 10A and Figure 10B As shown, the release opening 55 is formed through the upper structural layer 106, for example by photolithography and chemical etching steps.

[0120] The release opening 72 can also be formed together with the release opening 55.

[0121] Then, as Figure 11A and Figure 11B As shown, sacrificial layer 104 is removed.

[0122] The sacrificial layer 104 is removed by chemical etching (dry or wet etching) through release openings 55 and 72.

[0123] The compound used to remove the sacrificial layer 104 diffuses through release openings 55, 72, as indicated by arrow 109, into the entire area occupied by the sacrificial layer 104 in order to remove it.

[0124] exist Figure 11A and Figure 11B Following chemical etching, buried cavities 42, 65, and 66 are formed, and thus films 38, 60, and 61 and structural portions 51 and 71 are also formed.

[0125] Then, as Figure 12A and Figure 12B As shown, a sealing layer 110 made of oxides, nitrides or oxynitrides is deposited on the structural layer 106, extending over the release openings 55 (and 72) without entering the interior of the release openings 55 (and 72) or the interior of the cavities 42, 65, 66.

[0126] Depending on the specific application, the sealing layer 110 can be a single layer or multiple layers, including, for example, materials that are different from each other.

[0127] The sealing layer 110 may have a thickness, for example, between 0.5µm and 4µm; in this way, it is advantageous to form the sealing layer 110 continuously over the release opening 55, thereby ensuring a proper seal.

[0128] The sealing layer 110 is then patterned by photolithography and chemical etching steps in a manner not shown to form the sealing portion 56.

[0129] In practice, the sealing layer 110 is completely removed from the portion covering the detection membrane 38. Therefore, as described above, the sealing portion 56 does not affect the deformation characteristics of the detection membrane 38.

[0130] Furthermore, the presence of the release opening 55 inside the anchoring structure 40 and therefore close to the detection membrane 38 allows for reduced removal. Figure 11A and Figure 11B The etching time of the sacrificial layer 104.

[0131] The subsequent manufacturing steps are known in themselves and are therefore not shown or discussed here, such as packaging the wafer 100, forming electrical connections and cutting to form the pressure sensor 30.

[0132] Finally, it is obvious that modifications and variations can be made to the sensor 30 and the corresponding manufacturing process described and shown herein without departing from the scope of the invention as defined in the appended claims.

[0133] For example, substrate 31 may be formed of layers other than those shown. For example, depending on the specific application, layers 33, 34, and 35 may be single or multiple layers. Furthermore, conductive layer 35 may be made of a metallic material.

[0134] The number and arrangement of the anchoring portions 50, structural portions 51, and release openings 55 may differ from those shown. For example, only some structural portions 51 may have release openings 55.

[0135] Alternatively or alternatively, the anchoring structure 40 of the reference membrane 38 may have one or more parts without structural portions 51 and / or release openings 55.

[0136] For example, in addition to the anchoring portion 50 fixed to the substrate 31, the anchoring structure 40 may also have an end with other anchoring elements 115. Figure 4 (Top and bottom of the membrane). An additional anchoring element 115 extends parallel to the outer side of the detection membrane 38 and can help improve the support of the membrane 38.

[0137] For example, according to a specific embodiment, the sealing portion 56 may form a sealing region that includes portions that are different from or adjacent to each other.

[0138] For example, in a top view, one or more of the detection membrane 38 and reference membranes 60, 61 may have different shapes than those shown; for example, they may have different numbers of sides, or they may have circular, elliptical, or other planar shapes. For example, if the detection membrane 38 is circular, the feature dimension may be defined as the corresponding diameter.

[0139] In addition, the detection membrane 38 can be a deformable element of a different type and shape than the membrane, such as a cantilever.

[0140] Alternatively or alternatively, reference membranes 60 and 61 may be different types of suspension elements, such as cantilever arms.

[0141] For example, one or both of the reference membranes 60 and 61 may be absent. In this case, the peripheral sealing element for the transverse sealing cavity 42 may extend at the outer surface 46B of the anchoring structure 40, contacting the anchoring portion 50 and the structural portion 51.

[0142] For example, the pressure sensor 30 can be configured to detect the deformation of the detection membrane 38 by means of a transducer other than a capacitive transducer (e.g., piezoelectric, piezoresistive, etc.).

[0143] Finally, the different embodiments described above can be combined to provide other solutions.

Claims

1. A pressure sensor, comprising: substrate; A deformable detection element is suspended on the substrate, extends along a first direction at a distance from the upper surface of the substrate, and is configured to undergo deformation according to the pressure to be detected. as well as An anchoring structure is configured to support the deformable detection element on the substrate; The anchoring structure includes: Multiple anchoring portions extend from the substrate, are coupled to the deformable detection element, and are arranged at a distance from each other along a second direction, which is transverse to the first direction; as well as The structural region extends along the second direction between adjacent anchoring portions and has at least one release opening extending through the structural region.

2. The pressure sensor of claim 1, wherein the anchoring structure has an inner surface coupled to the deformable sensing element, the anchoring portion extending from the inner surface along a third direction transverse to both the first and second directions, wherein the anchoring portion has a first width along the third direction and a second width along the second direction.

3. The pressure sensor according to claim 2, wherein the first width is greater than the second width.

4. The pressure sensor of claim 2, wherein the deformable detection element has a first dimension along at least one of the second direction and the third direction, and wherein the ratio between the first width of the anchoring portion and the first dimension is greater than or equal to 4% and less than 20%.

5. The pressure sensor of claim 1, wherein the deformable sensing element has a second dimension along at least one of the second direction and the third direction, and wherein the ratio between the distance between two adjacent anchoring portions along the second direction and the second dimension is less than or equal to 8% and greater than 0.8%.

6. The pressure sensor of claim 1, wherein the width of the at least one release opening along the second direction is less than the distance between two adjacent anchoring portions along the first direction.

7. The pressure sensor of claim 6, wherein the difference between the width of the at least one release opening and the distance between two adjacent anchoring portions is greater than or equal to 0.5 µm.

8. The pressure sensor of claim 7 further includes a cavity disposed between the deformable sensing element and the substrate, wherein the release opening extending through the structural region is in fluid communication with the cavity.

9. The pressure sensor of claim 1, further comprising a sealing region configured to seal the at least one release opening.

10. The pressure sensor of claim 9, wherein the sealing region extends over the structural region of the anchoring structure.

11. The pressure sensor according to claim 1, further comprising: At least one suspension reference element is suspended on the substrate, a distance away from the substrate along the first direction, and is configured not to undergo deformation according to the pressure to be detected; as well as A reference anchoring structure is configured to support the at least one suspended reference element and is arranged at a distance from the anchoring structure of the deformable detection element. The reference anchoring structure includes: A plurality of corresponding anchoring portions extend from the substrate, are coupled to the suspension reference element, and are arranged at a distance from each other along the second direction; as well as The corresponding structural region extends between the anchoring portions along the second direction and has at least one corresponding release opening extending through the structural region.

12. A method for manufacturing a pressure sensor, comprising: A deformable detection element is formed from a wafer, the deformable detection element is suspended on the wafer, extends a distance from the wafer along a first direction, and is configured to undergo deformation according to the pressure to be detected; as well as An anchoring structure is formed from the wafer, the anchoring structure being configured to support the deformable detection element on the substrate. The anchoring structure includes: Multiple anchoring portions are formed, extending from the wafer, coupled to the deformable detection element, and arranged spaced apart from each other along a second direction, which is transverse to the first direction; as well as A structural region is formed, which extends between the anchoring portions along the second direction and has at least one release opening extending through the structural region.

13. The method of claim 12, wherein forming the deformable detection element and forming the anchoring structure comprises: A first structural layer and a sacrificial layer are formed on the wafer; A second structural layer is formed on the sacrificial layer and the first structural layer; The at least one release opening is formed in the second structural layer above the sacrificial layer; as well as The sacrificial layer is removed through the at least one release opening.

14. The method of claim 13, further comprising, after removing the sacrificial layer, forming at least one sealing region on the structural region of the anchoring structure and at the at least one release opening, the sealing region being configured to seal the at least one release opening.

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