Magnetic sensor equipment

Abstract

The present application discloses a magnetic sensor device. An integrated sensor device (920; 970; 1070) comprises: a semiconductor substrate comprising a horizontal Hall element (Hc) and an integrated magnetic flux concentrator (911; 1011) substantially above the horizontal Hall element (Hc), wherein the first magnetic flux concentrator has a shape whose geometric center is aligned with the geometric center of the horizontal Hall element; and wherein the shape has a height (H) and a lateral dimension (D), wherein H ≥ 30 μm and / or wherein (H / D) ≥ 25%. The integrated magnetic flux concentrator may be partially incorporated into an "interconnect stack" (1223; 1323). A method of producing such an integrated sensor device.

Description

Technical Field

[0001] The present invention generally relates to the field of magnetic sensor devices, such as position sensor devices, current sensor devices, proximity sensor devices, etc. The invention also relates to a method of producing such a device. Background Art

[0002] Magnetic sensor devices comprising a semiconductor substrate and at least one horizontal Hall element are known in the art. They are used, for example, in linear position sensor devices, angular position sensor devices, current sensor devices, presence detectors, proximity detectors, etc.

[0003] As is known, horizontal Hall elements can be used to measure the magnetic field component (Bz) oriented perpendicular to the semiconductor substrate, while vertical Hall elements and magnetoresistive elements can measure the magnetic field component (Bx, By) parallel to the semiconductor substrate.

[0004] A linear position sensor system or an angular position sensor system typically includes a position sensor device and a magnetic source, such as a permanent magnet.

[0005] A current sensor system generally includes a current sensor device and an electrical conductor, such as an integral conductor or an external conductor, such as a bus bar.

[0006] A proximity sensor system generally includes a sensor device and a conductive target that is movable relative to the sensor device.

[0007] There are many variations of magnetic sensor systems to address one or more of the following requirements: use simple or inexpensive magnetic structures, use simple or inexpensive sensor devices, be able to measure over a relatively large range, be able to make high-precision measurements, require only simple operations, be able to make high-speed measurements, be highly robust to positioning errors, be highly robust to external interference fields, provide redundancy, be able to detect errors, be able to detect and correct errors, have a good signal-to-noise ratio (SNR), etc. Often, two or more of these requirements conflict with each other, so a trade-off needs to be made.

[0008] There is always room for improvement and substitution. Summary of the invention

[0009] An object of an embodiment of the present invention is to provide an integrated sensor device (e.g., a semiconductor wafer, or a semiconductor die, or a packaged device comprising at least one semiconductor die, the die also being referred to as a "chip") capable of measuring physical quantities related to a magnetic field (e.g., linear position, angular position, current amplitude, proximity indication, etc.).

[0010] It is an object of embodiments of the present invention to provide an integrated sensor device comprising a semiconductor substrate, wherein a physical quantity (eg linear position, angular position, current amplitude, proximity indication, etc.) is measured with improved accuracy.

[0011] It is an object of embodiments of the present invention to provide an integrated sensor device comprising a semiconductor substrate, wherein a physical quantity is measured with an improved signal-to-noise ratio (SNR).

[0012] An object of embodiments of the present invention is to provide an integrated sensor device comprising a semiconductor substrate, wherein a physical quantity is measured with an improved signal-to-noise ratio (SNR) without increasing the size of the semiconductor substrate and / or without increasing power consumption.

[0013] An object of embodiments of the present invention is to provide an integrated sensor device comprising a semiconductor substrate with reduced dimensions while maintaining or even improving the measurement accuracy of physical quantities (e.g. linear position, angular position, current amplitude, proximity indication, etc.).

[0014] It is an object of embodiments of the present invention to provide an angular position sensor device having improved accuracy and / or reduced semiconductor substrate size.

[0015] It is an object of a particular embodiment of the invention to provide an angular position sensor device which is more compact, has improved accuracy, is highly insensitive to external interference fields, and has an angular range of 360°.

[0016] It is an object of embodiments of the present invention to provide a linear position sensor device having improved accuracy and / or reduced semiconductor substrate size.

[0017] It is an object of certain embodiments of the invention to provide a linear position sensor device which is more compact, has improved accuracy and is highly insensitive to external disturbing fields.

[0018] An object of embodiments of the present invention is also to provide a method for manufacturing such a sensor device.

[0019] It is an object of embodiments of the present invention to provide such a magnetic sensor structure or such a position sensor device which is suitable for use in an industrial and / or automotive environment.

[0020] These and other objectives are achieved by embodiments of the present invention.

[0021] According to a first aspect, the present invention provides an integrated sensor device comprising: a semiconductor substrate including a first horizontal Hall element; a first integrated magnetic flux concentrator located above the first horizontal Hall element; wherein the first magnetic flux concentrator has a shape whose geometric center is aligned with the horizontal Hall element; and wherein the shape has a height in a direction perpendicular to the semiconductor substrate and a maximum lateral dimension in a direction parallel to the semiconductor substrate; wherein the height of the magnetic flux concentrator is at least 30 μm, and / or wherein the ratio of the height to the above-mentioned maximum lateral dimension is at least 25%.

[0022] Or mathematically, where one or both of the following conditions are met: (i) H ≥ 30 μm; (ii) ratio = (H / D) ≥ 25%. The maximum lateral dimension can be a diameter or a maximum diagonal.

[0023] An advantage of such a sensor device is that the integrated magnetic flux concentrator (iMFC) is aligned with the horizontal Hall element in the sense that the center of the horizontal Hall element is essentially located on the above-mentioned axis, since the magnetic flux concentrator provides passive signal amplification (to a value greater than 100%) for the magnetic field lines oriented perpendicular to the semiconductor substrate (the so-called Bz component).

[0024] One advantage of such a sensor device is that the magnetic field component oriented perpendicular to the substrate can be measured more accurately (eg due to a higher signal-to-noise ratio).

[0025] A sensor device comprising an integrated magnetic flux concentrator (iMFC) is an advantage over an external magnetic flux concentrator because it allows (i) embedding the magnetic flux concentrator in an integrated device (eg, a chip package) and (ii) precise alignment of the iMFC to the horizontal Hall element.

[0026] While the specific shape or geometry of the iMFC is not critical to the invention (e.g. cylindrical or conical or prismatic or mushroom-shaped, etc.), the relative dimensions of the shape, such as the ratio of the "height" to the "diameter" of the shape, have an important impact on the performance of the sensor device.

[0027] In one embodiment, the shape of the integrated magnetic flux concentrator is an overall cylindrical shape, or an overall conical shape, or an overall truncated conical shape, or a rotationally symmetrical shape, or a circularly symmetrical shape about the longitudinal axis, or has an overall prismatic shape with a regular polygonal cross-section, for example, a hexagonal prism, or has an overall mushroom shape, or is mainly composed of cylindrical parts, or is mainly composed of conical parts, or is mainly composed of truncated conical parts.

[0028] It should be noted that the vertical wall(s) of the magnetic field concentrator may not be completely perpendicular to the semiconductor substrate, but may be tilted relative to the orthogonal orientation. The tilt angle may be an angle in the range of about 1° to about 25° from the sequential direction.

[0029] In one embodiment, the conical shape or the truncated conical shape or the conical portion or the truncated conical portion tapers towards the horizontal Hall element.

[0030] In one embodiment, the integrated magnetic flux concentrator has a shape with a substantially planar bottom surface parallel to the semiconductor substrate.

[0031] In one embodiment, the integrated magnetic flux concentrator has a shape with a substantially planar top surface parallel to the semiconductor substrate.

[0032] In one embodiment, the height is a value in the range of 30 μm to 500 μm, 30 μm to 250 μm, 30 μm to 125 μm, or 30 μm to 80 μm.

[0033] In one embodiment, a height (H) of the shape in a direction perpendicular to the semiconductor substrate is in a range of 20 μm to 60 μm.

[0034] In one embodiment, the integrated magnetic flux concentrator (iMFC) has a shape having a substantially circular cross-section in a plane parallel to the semiconductor substrate. Preferably, the diameter (D) of the circular cross-section located halfway between the bottom surface and the top surface is in the range of 15 μm to 40 μm or 20 μm to 35 μm.

[0035] In one embodiment, the iMFC has a shape in which the height extends in a direction perpendicular to the semiconductor substrate, and the diameter or the maximum diagonal extends in a direction parallel to the semiconductor substrate, and the ratio R of the height to the diameter or the diagonal (R=H / D) is greater than 30%, or greater than 40%, or greater than 50%, or greater than 60%, or greater than 70%, or greater than 80%, or greater than 90%, or greater than 100%, or greater than 105%, or greater than 110%. It should be noted that a typical integrated IMC in the form of a disk generally has a height of about 23 μm and a diameter of about 190 μm, and thus has a ratio R=H / D of about 12%.

[0036] In a preferred embodiment, the shape of the iMFC has a height in the range of 20 μm to 60 μm and a diameter in the range of 15 μm to 40 μm.

[0037] In one embodiment, the shape of the integrated magnetic flux concentrator has a cross-section with a diameter or maximum diagonal in a plane parallel to the semiconductor substrate in the range of 15 μm to 40 μm, 15 μm to 35 μm, 16 μm to 34 μm, 17 μm to 33 μm, 18 μm to 32 μm, 19 μm to 31 μm, or 20 μm to 30 μm.

[0038] Surprisingly, the maximum gain Gz is obtained for a shape having an overall circular cross-section with a diameter of about 15 microns to 35 microns, or for a shape having a generally polygonal cross-section with a maximum diagonal of about 1535 to 35 microns.

[0039] In one embodiment, an orthogonal projection of the horizontal Hall element (Hc) on the substrate is completely within the edge of an orthogonal projection of the bottom surface of the integrated magnetic flux concentrator on the substrate.

[0040] In one embodiment, an orthogonal projection of the bottom surface of the integrated magnetic flux concentrator on the substrate is completely within the edge of an orthogonal projection of the horizontal Hall element (Hc) on the substrate.

[0041] In one embodiment, an edge of an orthogonal projection of the horizontal Hall element (Hc) on the substrate intersects an edge of an orthogonal projection of the bottom surface of the integrated magnetic flux concentrator on the substrate.

[0042] In one embodiment, the horizontal Hall element has a first area (A1), the bottom surface of the integrated magnetic flux concentrator (911) has a second area (A2); and the ratio of the first area (A1) to the second area (A2) is a value in the range of 50% to 200%.

[0043] In one embodiment, the ratio A1 / A2 is a value in the range of 80% to 120% or 90% to 110%, for example equal to about 100%.

[0044] In one embodiment, the ratio A1 / A2 is less than 95, or less than 90%, or less than 85%, or less than 80%, or less than 75%, or less than 70%, or less than 65%, or less than 60%, or less than 55%, for example, equal to about 50%.

[0045] In one embodiment, the ratio A1 / A2 is greater than 105%, or greater than 110%, or greater than 120%, or greater than 130%, or greater than 140%, or greater than 150%, or greater than 160%, or greater than 170%, or greater than 180%, or greater than 190%, for example equal to about 200%.

[0046] One advantage of an embodiment is that the area of ​​the horizontal Hall element is only a small fraction of the area of ​​the iMFC, because this allows magnetic flux lines that are not substantially vertically oriented to leave the iMFC without passing through the surface of the horizontal Hall element, in other words, because this reduces leakage or crosstalk from the Bx field or Bz field that is erroneously measured as the Bz field.

[0047] An advantage of an embodiment is that the area of ​​the horizontal Hall element is substantially equal to the area of ​​the iMFC, as this provides a relatively large signal.

[0048] In one embodiment, the sensor device is a current sensor device.

[0049] In one embodiment, the sensor device is a position sensor device.

[0050] An advantage of such a position sensor device is that the magnetic field component perpendicular to the substrate can be measured more accurately (eg due to a higher signal-to-noise ratio) and therefore the current or position derived therefrom (eg linear position or angular position) can also be determined more accurately.

[0051] In one embodiment, the sensor device is a linear position sensor device.

[0052] In one embodiment, the sensor device is an angular position sensor device.

[0053] In one embodiment, the distance between the horizontal Hall element and the integrated magnetic flux concentrator is a value in the range of 1 μm to 20 μm, 1 μm to 15 μm, 1 μm to 12 μm, or 1 μm to 10 μm.

[0054] In one embodiment, a semiconductor substrate includes an interconnect stack including at least four metal layers separated by a plurality of insulating layers; and wherein at least a portion of the integrated magnetic flux concentrator is located within the interconnect stack.

[0055] In one embodiment, the bottom of the integrated flux concentrator extends to the fourth metal layer (M4), away from the active surface of the substrate implementing the horizontal Hall element. In this case, the distance between the Hall plate and the iMFC can be a value in the range of about 8 μm to about 12 μm, for example, equal to about 10 μm.

[0056] In one embodiment, the bottom of the integrated magnetic flux concentrator extends to the third metal layer (M3). In this case, the distance between the Hall plate and the iMFC can be a value in the range of about 5 μm to about 9 μm, which is equal to about 7 μm.

[0057] In one embodiment, the bottom of the integrated magnetic flux concentrator extends to the second metal layer (M2), which is the second metal layer closest to the active surface of the horizontal Hall element. In this case, the distance between the Hall plate and the iMFC can be a value in the range of about 2 μm to about 6 μm, which is equal to about 4 μm.

[0058] In one embodiment, the bottom of the integrated magnetic flux concentrator extends to the first metal layer (M1), i.e., the metal layer closest to the active surface implementing the horizontal Hall element (Hc). In this case, the distance between the Hall plate and the iMFC can be a value in the range of about 0.5 μm to about 2.5 μm, about 1 μm, or about 2 μm.

[0059] Implementing the iMFC at least partially in an "interconnect stack" is an advantage because it allows the distance between the Hall element and the iMFC to be reduced, and allows the passive amplification gain Gz to be increased (for an iMFC of a given size and shape) without having to adjust the size of the interconnect stack. Or in other words, by bringing the iMFC closer to the horizontal Hall element, the size of the iMFC can be reduced for a given passive amplification gain factor Gz. This can have a significant impact on layout (e.g., smaller die size) and / or process cost (e.g., an iMFC with reduced thickness requires less production time).

[0060] Therefore, the technology allows the construction of sensor devices with higher accuracy or smaller die size, or both.

[0061] In one embodiment, the semiconductor substrate has an active surface including the above-mentioned horizontal Hall element and a passive surface opposite to the active surface; and the integrated magnetic flux concentrator is located on the side of the active surface.

[0062] In one embodiment, the semiconductor substrate has an active surface including the above-mentioned horizontal Hall element and a passive surface opposite to the active surface; and the integrated magnetic flux concentrator is located on the side of the passive surface.

[0063] In one embodiment, the integrated sensor device further includes a second magnetic flux concentrator, which has an annular shape with an inner diameter greater than an outer diameter of the first magnetic flux concentrator and is arranged concentrically with the first magnetic flux concentrator; and wherein the semiconductor substrate also includes at least second and third horizontal Hall elements, which are arranged near the edge of the second integrated magnetic flux concentrator.

[0064] In one embodiment, the integrated sensor device further includes a plurality of second integrated magnetic flux concentrators, each of the plurality of second integrated magnetic flux concentrators having an elongated shape and being radially oriented relative to the first horizontal Hall element; and wherein the semiconductor substrate further includes a plurality of further horizontal Hall elements, the plurality of further horizontal Hall elements being arranged near the edges of the corresponding second integrated magnetic flux concentrators.

[0065] One advantage is that the first horizontal Hall element located below the first IMFC is located between (eg substantially in between) the second and third or further horizontal Hall elements as it will experience substantially the same temperature and will therefore be subject to less temperature drift.

[0066] In one embodiment, the semiconductor substrate further includes a second magnetic flux concentrator having a ring shape or a disk shape, and further includes at least second and third horizontal Hall elements arranged near an edge of the second integrated magnetic flux concentrator.

[0067] In one embodiment, the semiconductor substrate further includes a plurality of second magnetic flux concentrators having an elongated shape, and further includes a plurality of horizontal Hall elements, each of the plurality of horizontal Hall elements being arranged near an edge of a corresponding elongated shape.

[0068] In one embodiment, the integrated sensor device further includes a second semiconductor substrate; wherein the second semiconductor substrate includes a second magnetic flux concentrator having a ring shape or a disk shape, and further includes at least second and third horizontal Hall elements, which are arranged near the edge of the second integrated magnetic flux concentrator; or wherein the second semiconductor substrate includes a plurality of second magnetic flux concentrators having an elongated shape, and further includes a plurality of horizontal Hall elements, each of the plurality of horizontal Hall elements being arranged near the edge of a relative elongated shape; and wherein the first semiconductor substrate and the second semiconductor substrate are stacked on top of each other or adjacent to each other and interconnected by bonding wires.

[0069] According to the second aspect, the present invention also provides a method for producing an integrated sensor device, comprising the following steps: a) providing a semiconductor substrate including a first horizontal Hall element; b) providing a photoresist layer on the top of the semiconductor substrate; c) forming an opening or a cavity in the top layer of the semiconductor substrate so that the center of the opening or the cavity is basically aligned with the center of the first horizontal Hall element; d) providing (for example, depositing) a soft magnetic material in the opening or the cavity to form a first magnetic flux concentrator having a shape along an axis perpendicular to the semiconductor substrate and passing through the above-mentioned first horizontal Hall element.

[0070] The “height direction” refers to a direction perpendicular to the semiconductor substrate.

[0071] "Lateral dimension" refers to a direction perpendicular to the height direction and thus refers to a dimension parallel to the semiconductor substrate, such as a diameter or a diagonal.

[0072] Steps b) to d) are preferably performed such that the height H and the maximum diameter or the maximum diagonal of the iMFC satisfy at least one of the following conditions: (i) H ≥ 30 μm, (ii) (H / D) ≥ 25%

[0073] In one embodiment, step a) includes: providing a semiconductor substrate, the semiconductor substrate including a first horizontal Hall element and including an interconnect stack, the interconnect stack including at least four metal layers separated by multiple insulating layers; wherein step b) includes: removing at least a portion of at least one of the above-mentioned insulating layers.

[0074] The interconnect stack can be designed so that no metal interconnects pass through the space that the iMFC will occupy.

[0075] Although not absolutely required, one of the metal layers may include a metal portion that serves as an etch stop. This metal portion may be located in any of the four metal layers of the interconnect stack.

[0076] According to another aspect, the invention also provides a current sensor system comprising the sensor device according to the first aspect and an electrical conductor.

[0077] According to another aspect, the invention also provides a linear position sensor system comprising a sensor device according to the first aspect and a magnetic source having an elongated shape and a plurality of at least four poles.

[0078] According to another aspect, the present invention further provides an angular position sensor system, the angular position sensor system comprising the sensor device according to the first aspect and a magnetic source. The magnetic source may be a dipole magnet, a quadrupole magnet or a magnet with more than four poles.

[0079] Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not just as explicitly set out in a claim.

[0080] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

[0081] BRIEF DESCRIPTION OF THE DRAWINGS

[0082] Figure 1 (a) to Figure 1 (c) shows an angular position sensor system known in the art.

[0083] FIG2(a) is a schematic diagram of a sensor device including four sensor structures, each sensor structure including a horizontal Hall element and an integrated magnetic flux concentrator (iMFC) aligned with the Hall element, as proposed by the present invention. In the example of FIG2, the iMFC has a conical shape, but the present invention is not limited thereto. FIG2(b) shows an orthogonal projection of the bottom surface of the flux concentrator on a semiconductor substrate. FIG2(c) shows a side view of one such sensor structure.

[0084] Figure 3 An example is shown of how the field lines of a uniform magnetic field oriented in the X direction parallel to the semiconductor substrate may be deformed by an illustrative embodiment of a sensor structure as shown in FIG. 2( c ).

[0085] Figure 4(a) to Figure 4(c) Exemplary embodiments of sensor structures with various aspect ratios as shown in FIG. 2( c ) are shown, and illustrate how the field lines of a uniform magnetic field oriented in the negative Z direction perpendicular to the semiconductor substrate are deformed by the sensor structure.

[0086] FIG. 5(a) and FIG. 5(b) show a method similar to that shown in FIG. 2(c) or Figure 4(a) to Figure 4(c) The magnetic gain Gz in the Z direction provided by the sensor structure but with a cylindrical shape obtained by simulation. In Figure 5(a), the magnetic gain Gz is shown as a function of the diameter of the magnetic flux concentrator at different heights. In Figure 5(b), the magnetic gain Gz is shown as a function of the height of the magnetic flux concentrator for various diameters.

[0087] Figure 6(a) to Figure 6(d) Figure 2(c) and Figure 4(a) to Figure 4(c) Variations of magnetic sensor structures. In Figure 6(a), the iMFC has a cylindrical shape. Figure 6(b) to Figure 6(d) In the figure, the iMFCs are prisms with square, hexagonal, and octagonal cross-sections, respectively.

[0088] Fig. 7(a) shows a perspective view, and Fig. 7(b) shows a cross-sectional view of another embodiment of a magnetic sensor structure capable of measuring two orthogonal components Bx and Bz of a magnetic field proposed by the present invention. The sensor structure comprises: a central horizontal Hall element and a first (e.g., cylindrical) iMFC aligned with the central Hall element; a second iMFC in an annular shape, which is arranged concentrically with the first iMFC; and a pair of horizontal Hall elements, which are located near the edge of the ring and on opposite sides of the ring.

[0089] FIG7( c ) shows a structural variation of FIG7( a ), in which five horizontal Hall elements are another embodiment of the magnetic sensor structure proposed by the present invention, capable of measuring three orthogonal magnetic field components Bx, By, and Bz.

[0090] FIG8(a) shows a top view of another embodiment of a magnetic sensor structure capable of measuring three orthogonal magnetic field components Bx, By, and Bz proposed by the present invention. The structure includes a central Hall element and a first IMFC located above and aligned with the central Hall element, and further includes four horizontal Hall elements and four elongated IMFC elements, forming a "sun shape".

[0091] FIG8( b ) shows a variation of FIG8( a ) in a top view as another embodiment of the magnetic sensor structure proposed by the present invention, which is capable of measuring three orthogonal magnetic field components Bx, By, Bz.

[0092] FIG. 9( a ) is a schematic diagram of a sensor device according to an embodiment of the present invention, comprising a semiconductor substrate having at least one magnetic sensor structure as described above, for example, as shown in FIG. 2( c ) or FIG. Figure 4(a) to Figure 4(c) shown.

[0093] FIG. 9( b ) is a schematic diagram of a sensor device according to an embodiment of the present invention, comprising two semiconductor substrates, at least one of which comprises a sensor structure as described above, such as shown in FIG. 2( c ) or Figure 4(a) to Figure 4(c) shown.

[0094] Fig.10 is a schematic diagram of a semiconductor substrate including a Hall sensor arrangement having an IMC arranged in a disk or ring or sun shape (eg Fig.10 2(c) or 2(c) implemented on the same substrate. Figure 4(a) to Figure 4(c) The sensor structure shown (such as Fig.10 shown on the right).

[0095] Fig.11 A flow chart showing a method of producing a sensor device, the sensor device comprising a sensor device as shown in FIG. 2( c) or Figure 4(a) to Figure 4(c) The magnetic sensor structure shown.

[0096] Fig.12 It is shown that by executing Fig.11 The steps of the method are to obtain an intermediate semiconductor structure.

[0097] Fig.13 It is shown that by executing Fig.11 A variant of the method obtains an intermediate semiconductor structure, wherein the iMFC is at least partially implemented within an interconnect stack.

[0098] Fig.14 (a) and Fig.14 (b) shows another embodiment of the magnetic sensor structure according to the present invention, comprising two structures as shown in FIG. 2(c), which are spaced apart by a distance Δx along the axis in the perspective view and the top view, respectively.

[0099] Fig.15 Another embodiment of a magnetic sensor structure according to the present invention is shown, which comprises three structures as shown in FIG. 2( c ) which are equally spaced along the axis.

[0100] Fig.15 (b) is a linear position sensor including a multi-pole magnetic structure and Fig.15 (a) Schematic diagram of the magnetic sensor structure shown.

[0101] Fig.15 (c) is a device comprising a quadrupole ring magnet and an off-axis Fig.15 (a) Angular position sensor with magnetic sensor structure shown.

[0102] Fig.15 (d) shows Fig.15 A variation of the magnetic sensor structure of (a), in which the sensor elements are located on a triangle, can be used in linear or angular position sensor systems.

[0103] Fig.15 (e) shows Fig.15 A variation of the magnetic sensor structure of (a), comprising four sensor elements arranged equidistantly along the axis, can be used in linear or angular position sensor systems.

[0104] Fig.15 (f) shows Fig.15 A variation of the magnetic sensor structure of (a), which contains four sensor elements located on a trapezoid, can be used in linear or angular position sensor systems.

[0105] Fig.16 (a) and Fig.16 (b) shows a variation of the magnetic sensor structure of FIG. 2(a) in perspective and top view, comprising three sensor structures shown in FIG. 2(c) located on an imaginary circle and spaced angularly at multiples of 120°.

[0106] Fig.16 (c) shows an angle sensor system, which includes a two-pole magnet and a magnetic sensor structure, such as Fig.16 (a) and Fig.16 (b) as shown.

[0107] Fig.17 (a) and Fig.17 (b) shows the perspective view and the top view of FIG. 2(a) and Fig.16 A variation of the magnetic sensor structure of (a), including six sensor structures shown in Figure 2(c), which are located on a virtual circle and spaced at multiples of 60°.

[0108] Fig.17 (c) shows a quadrupole magnet and Fig.17 (a) and Fig.17 (b) Angle sensor system with magnetic sensor structure shown.

[0109] The drawings are schematic and non-limiting. In the drawings, for illustrative purposes, the size of some of the elements may be exaggerated and not drawn to scale. Any reference numerals in the claims should not be interpreted as limiting the scope. In different drawings, the same reference numerals refer to the same or similar elements. DETAILED DESCRIPTION

[0110] The present invention will be described with respect to specific embodiments and with reference to certain drawings, but the invention is not limited thereto but only by the claims. The drawings described are only schematic and non-limiting. In the drawings, for illustrative purposes, the dimensions of some of the elements may be exaggerated and not drawn to scale. The dimensions and relative dimensions do not correspond to actual reductions to the implementation of the invention.

[0111] Furthermore, the terms first, second, etc. in the specification and in the claims are used to distinguish between similar elements and are not necessarily used to describe a sequence in time, space, in ranking, or in any other manner. It is understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in a different sequence than described or illustrated herein.

[0112] Furthermore, the terms top, bottom, etc. in the specification and claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances, and that the embodiments of the invention described herein are capable of operation in orientations other than those described or illustrated herein.

[0113] It is to be noted that the term "comprising" used in the claims should not be interpreted as being limited to the means listed thereafter; it does not exclude other elements or steps. Therefore, the term should be interpreted as specifying the presence of the stated features, integers, steps or components as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Therefore, the scope of the expression "a device comprising means A and B" should not be limited to a device consisting only of components A and B. It means that for the present invention, the only relevant components of the device are A and B.

[0114] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, the appearances of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification do not necessarily all refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, as will be apparent to one of ordinary skill in the art from this disclosure, the particular features, structures, or characteristics may be combined in any suitable manner.

[0115] Similarly, it should be understood that in the description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the present disclosure and assisting in the understanding of one or more of the various inventive aspects. However, this disclosure method should not be interpreted as reflecting an intention that the claimed invention requires more features than those expressly recited in each claim. On the contrary, as reflected in the appended claims, inventive aspects reside in fewer features than all of the features of a single preceding disclosed embodiment. Therefore, the claims appended after the detailed description are hereby expressly incorporated into this specific implementation, with each claim itself representing a separate embodiment of the present invention.

[0116] In addition, although some embodiments described herein include some features included in other embodiments but do not include other features included in other embodiments, as will be understood by those skilled in the art, the combination of features of different embodiments is intended to fall within the scope of the present invention and form different embodiments. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

[0117] In the description provided herein, numerous specific details are set forth. However, it should be understood that embodiments of the present invention may be practiced without these specific details. In other examples, well-known methods, structures, and techniques are not shown in detail to avoid confusing the understanding of this description.

[0118] In this document, the terms “integrated magnetic concentrator” (IMC) and “integrated magnetic flux concentrator” (iMFC) have the same meaning.

[0119] Figure 1 (a) to Figure 1 (c) shows an angular position sensor system 100 known from WO98547A1, which is incorporated herein by reference in its entirety.

[0120] This application Figure 1 (a) is published by the WO Figure 1A replica of , showing a bar magnet that can rotate relative to a substrate. The substrate includes four horizontal Hall elements arranged in a circle.

[0121] This application Figure 1 (b) is a copy of Figure 2 of the WO publication and shows a perspective view of the sensor elements of the sensor device. The sensor device 102 comprises four horizontal Hall elements 4, 5, 6, 7 arranged on a circle for providing signals S4, S5, S6, S7 respectively. The sensor elements are angularly spaced at multiples of 90°. The first differential signal is calculated as (S7-S6). The second differential signal is calculated as (S5-S4). The angular position of the magnet is calculated using the following formula:

[0122] θc=arctan((S7-S6) / (S5-S4)) [1]

[0123] S4 and S5 are located at radially opposite positions to each other, and S6 and S7 are located at radially opposite positions to each other. It should be noted that the priority date of the WO application dates back to May 1997, which is more than 23 years ago, which is huge, especially in the highly competitive field of electronics, especially in the field of electronics for industrial and automotive applications. Figure 1 (a) to Figure 1 The arrangement shown in (c) has very advantageous properties, for example it provides a 360° measuring range and is largely insensitive to (uniform) external interference fields. These are very desirable properties, for example in motor applications.

[0124] However, one disadvantage of this arrangement is that it cannot be easily scaled down. For example, if the size of the magnet and the size of the horizontal Hall element and the distance between them are reduced, the influence of mechanical tolerance and process tolerance increases, the sensor signal becomes very small, the differential signal becomes very small, the signal-to-noise ratio (SNR) of the signal decreases, and the accuracy of the sensor system decreases.

[0125] The question facing the inventors is whether it is possible to improve Figure 1 (a) to improve the accuracy of the sensor arrangement shown and / or reduce the size of the sensor arrangement. At the time of filing the WO publication, Figure 1The distance between the Hall elements in (a) may be about 2.5 mm, so the challenge is whether the distance between diametrically opposed horizontal Hall elements can be reduced to a maximum of 2.0 mm, or a maximum of 1.8 mm, or a maximum of 1.6 mm, or a maximum of 1.5 mm, or a maximum of 1.4 mm, or a maximum of 1.3 mm, or a maximum of 1.2 mm, or a maximum of 1.0 mm, or to a maximum of 0.9 mm, or to a maximum of 0.8 mm, or to a maximum of 0.7 mm, or to a maximum of 0.6 mm, or to a maximum of 0.5 mm while still providing an angular position sensor with considerable accuracy (e.g., an angular error of a maximum of 2.0°, or a maximum of 1.5°, or a maximum of 1.0°, or a maximum of 0.7°, or a maximum of 0.5°).

[0126] The inventors conceived of providing an integrated sensor device having a magnetic sensor structure schematically illustrated in FIG. 2( a ), comprising a plurality of horizontal Hall elements H1 to H4 , and further comprising a plurality of integrated magnetic flux concentrators iMFC1 to iMFC4 , each aligned with a corresponding underlying horizontal Hall element.

[0127] This was one of the ideas underlying the present invention and was the start of a research project because they did not know if this was actually possible, whether the performance would improve, by how much, and how to do it in a cost-effective way, for example in a CMOS process.

[0128] This is not a simple idea because (i) existing magnetic sensor structures including (an) integrated flux concentrator are generally used to bend horizontal flux lines into vertical flux lines so that the Bx or magnetic field component can be measured by the horizontal Hall element; and (ii) in existing solutions, the horizontal Hall element is located at the edge of the IMFC, rather than at its center; and (iii) known integrated flux concentrators generally have a disk shape with a relatively large diameter of about 200μm and a height (or thickness) of about 20μm to 25μm (thus having an aspect ratio of about 10 / 1). It is not realistic to build a similar iMFC structure in the substrate height direction. Moreover, it is also not realistic to reduce the size by nearly 10 times and expect to get the same results. In short, the inventors do not know what to expect, or more specifically, what the performance of iMFCs of medium height and / or medium height / diameter ratios will be, and / or whether it is possible to implement such an iMFC in an integrated solution because CMOS and more generally microfabrication technologies are not well suited to building "vertical structures" at the microscale.

[0129] The inventors created a computer model of a sensor arrangement that includes a horizontal Hall element and a magnetic flux concentrator having various shapes that includes or consists of a soft magnetic material, and performed simulations to verify how the structure reacts to magnetic fields of different directions. The computer simulations were performed using a computer program called COMSOL. ” software simulation program, which was commercially available at the time of writing this application, but other simulation tools can also be used.

[0130] FIG. 2( b) shows an orthogonal projection of the bottom surface of the flux concentrator on a semiconductor substrate. In the example shown, the bottom surface area of ​​the iMFC is slightly larger than the area of ​​the horizontal Hall element, but this is not an absolute requirement for the invention to work, and alternative embodiments are also envisioned in which the ratio of the length of the diagonal of the Hall element to the diameter of the circular bottom surface is in the range of 50% to 200%, or 60% to 170%, or 70% to 140%, or 80% to 125%, or 90% to 110%. In some embodiments, the projected area of ​​the bottom surface of the iMFC is larger than the projected area of ​​the Hall element. In some embodiments, the projected area of ​​the bottom surface of the iMFC is smaller than the projected area of ​​the Hall element. In some embodiments, the projected area of ​​the horizontal Hall element is completely contained within the edge of the projection of the bottom surface of the iMFC. In some embodiments, the projected area of ​​the bottom surface of the iMFC is completely contained within the projected area of ​​the horizontal Hall element. In some embodiments, the edge of the projected area of ​​the bottom surface of the iMFC intersects with the edge of the projected area of ​​the horizontal Hall element. The Hall element can have a substantially square shape.

[0131] Figure 2(c) shows a side view of such a magnetic sensor structure, further showing various dimensions such as: iMFC top surface diameter "Dt", iMFC bottom surface diameter "Db", iMFC height "H", distance "d" between the horizontal Hall element and the iMFC bottom surface, and the width "W" of the horizontal Hall element. The expected values ​​of Dt, Db, and H are 20μm to 80μm; the expected value of "d" is 1μm to 20μm; and the typical value of W is 5μm to 50μm.

[0132] Figure 3 The results of such a simulation using an iMFC 111 having a truncated cone shape with an axis aligned above the center of the horizontal Hall element 101 are shown. The bottom surface of the iMFC is at a distance "d" from the horizontal Hall element. A uniform field Bx is applied in the X direction. The following table lists the geometrical parameters of the simulated arrangement, but the invention is of course not limited thereto.

[0133] Figure 3 Hall element size 15μm x 15μm Height of iMFC (H) 60μm iMFC bottom diameter 20μm Angle of the side wall of iMFC (λ) 100° The distance between Hall and iMFC 12μm

[0134] It can be seen that the magnetic field lines "seen" by the horizontal Hall element 101 are substantially parallel to the horizontal Hall element, and they are substantially symmetrical about an imaginary vertical symmetry plane passing through the center (not shown), so the horizontal Hall element does not measure a net signal.

[0135] Figure 4(a) to Figure 4(c) Grayscale images and simulation results for three magnetic sensor arrangements in the presence of a negative Z-directed uniform magnetic field are shown, each magnetic sensor arrangement comprising a horizontal Hall element and an integrated magnetic flux concentrator (iMFC) having a substantially truncated cone shape with the axis aligned with the center of the horizontal Hall element. The following table lists the geometric parameters of these arrangements:

[0136]

[0137] It can be seen that the magnetic field lines sensed by the horizontal Hall element are substantially orthogonal to the horizontal Hall element, and therefore, they can be measured by the horizontal Hall element. The contrast of the grayscale image represents the magnetic field strength and magnetic field amplification: "bright" represents a relatively high amplitude, "dark" represents a relatively low amplitude, and therefore bright spots represent locations with "amplification".

[0138] The simulation also shows that the smaller the distance "d" between the Hall element and the bottom surface of the iMFC, the higher the amplification, which will be utilized in Fig.13 The method shown provides a sensor device in which the iMFC is partially implemented in a so-called "interconnect stack" (sometimes also called a "metal stack").

[0139] Since the magnetic field directed in any direction can be decomposed into components Bx and By parallel to the horizontal Hall element (will not be sensed) and component Bz perpendicular to the horizontal Hall element (will be sensed), it can be obtained from Figure 3 and Figure 4(a) to Figure 4(c) It is understood that a magnetic field assembly having a horizontal Hall element and a top iMFC aligned with the horizontal Hall element can be used to measure the Bz field.

[0140] To get a better impression of the magnetic field gain, other simulations were performed. In these simulations, an iMFC made of FeNi and having a cylindrical shape (thus the angle λ of the side walls is 90°) with a bottom surface diameter (D) of 30 μm, a distance (d) between the Hall and the iMFC of 12 μm, and a horizontal Hall element with a square (WxW) of 15 μm x 15 μm was used.

[0141] Figure 5(a) shows the magnetic gain Gz provided by cylindrical iMFCs with various diameters (from 20 μm to 60 μm) as a function of the iMFC height. It can be seen that for a given diameter, an iMFC with a larger height provides a larger gain Gz. For example, for an iMFC with a diameter of about 30 μm and a height of about 20 μm (curve with squares), the gain Gz is approximately equal to 1.34, which is much higher than expected. As another example, if the height of this iMFC is increased to about 60 μm, the gain Gz will increase to about 1.92 (curve with triangles), which is huge. And it is also very surprising that for any given height in the range of 20 μm to 60 μm, the gain Gz is maximum when the diameter D is about 20 μm to 30 μm.

[0142] FIG5( b ) shows the magnetic gain Gz of the integrated magnetic flux concentrator iMFC with various diameters as a function of the iMFC height H. It can be seen that the gain Gz increases roughly linearly with the height H. It can be seen that for a given height H, the gain Gz increases as the diameter decreases from 60 μm to about 30 μm, but if the diameter is further reduced to about 20 μm, the gain Gz remains essentially constant (the curve with circles and the curve with diamonds are very close to each other).

[0143] As a rule of thumb, for shapes with upright walls (λ=90°) and a diameter (in the case of cylindrical shapes) or a “largest diagonal” (for prisms, see e.g. Figure 6(a) to Figure 6(d) ) is about 20 microns to 30 microns of the integrated magnetic flux concentrator (iMFC), the gain Gz can be approximately calculated by the following formula:

[0144] Gz=1.05+(0.0145*H) [2]

[0145] Where Gz is the magnetic gain and H is the height of the iMFC in micrometers.

[0146] As some examples:

[0147] - For a cylindrical iMFC with D = 20 μm to 30 μm and H = 20 μm, Gz is equal to about 1.34

[0148] - For a cylindrical iMFC with D = 20 to 30 microns and H = 23 microns, Gz equals about 1.38

[0149] - For a cylindrical iMFC with D = 20 to 30 microns and H = 30 microns, Gz equals about 1.49

[0150] - For a cylindrical iMFC with D = 20 to 30 microns and H = 40 microns, Gz equals about 1.63

[0151] - For a cylindrical iMFC with D = 20 to 30 microns and H = 50 microns, Gz equals about 1.77

[0152] - For a cylindrical iMFC with D = 20 to 30 microns and H = 60 microns, Gz equals about 1.92

[0153] Surprisingly, a magnetic sensor arrangement with a cylindrical flux concentrator of only about 20 μm in diameter D and only about 20 μm in height H provided a passive amplification of a factor of 1.34, meaning it produced a 34% larger signal than a horizontal Hall element without the flux concentrator. This was an unpredictable and dramatic improvement.

[0154] This insight can be used to build magnetic sensor structures that can provide larger signal amplitude (Bz) by adding an iMFC on top of a horizontal Hall element, thereby achieving better signal-to-noise ratio and higher accuracy. Additionally or alternatively, for example when determining gradient signals (e.g., dBz / dx and dBz / dy in the configuration of Figure 2(a)), or when determining differential signals between pairs of values ​​(see e.g. Fig.15 ), the gain Gz provided by the iMFC can be used to reduce the distance “dx” between the horizontal Hall elements without degrading their signal-to-noise ratio (SNR).

[0155] For the sake of completeness, it should be noted that the magnetic gain Gz will generally increase if the distance "d" decreases, and / or if the angle λ of the sidewalls decreases (less than 90°). As long as the diameter D of the iMFC is larger than the diagonal of the Hall plate (W*√2), the gain Gz will remain essentially unchanged. For iMFCs of smaller diameters, the magnetic gain may decrease. As already mentioned above, the gain Gz of an iMFC with a truncated cone shape of the same height H will be larger than the values ​​shown in Figures 5(a) and 5(b).

[0156] Although FeNi as a soft magnetic material is simulated, the present invention is certainly not limited thereto, and other soft magnetic materials may also be used, such as amorphous metal alloys, such as iron-based alloys, nickel-based alloys, iron-nickel-based alloys, and cobalt-based alloys. The alloy may also contain one or more of: silicon, boron, carbon, and copper.

[0157] Figure 6(a) to Figure 6(d) Examples of sensor structures including a horizontal Hall element and an integrated magnetic flux concentrator aligned therewith are shown, wherein the iMFC has various shapes. These sensor structures can also be used in embodiments of the present invention, but the present invention is not limited thereto. FIG. 6( a ) shows a cylindrical shape, FIG. 6( b ) shows a prism with a square cross-section, FIG. 6( c ) shows a prism with a hexagonal cross-section, and FIG. 6( d ) shows a prism with an octagonal cross-section. From these examples, it can be clearly seen that other prisms with regular or irregular polygonal cross-sections can also be used.

[0158] In practice, the upright walls may not be perfectly orthogonal to the semiconductor substrate, but this is not necessary for the invention to work. In fact, it may even be beneficial (in terms of increased gain) to use a structure where the walls are slightly tilted so that the iMFC gradually tilts towards the horizontal Hall element located underneath.

[0159] The distance "d" between the horizontal Hall element and the integrated flux concentrator is preferably less than 25 μm, or less than 20 μm, or less than 15 μm, or less than 12 μm, or less than 9 μm, or less than 6 μm, or less than 5 μm, or less than 4 μm. Although the distance "d" is not critical for the present invention to work (as long as it is less than about 30 μm), the gain Gz provided by the integrated flux concentrator can decrease slightly as the distance "d" increases.

[0160] The present invention also proposes a magnetic sensor structure comprising one or more sensor structures, as shown in FIG. 2( c ) and / or Figure 4(a) to Figure 4(c) shown.

[0161] FIG7( a) shows a perspective view of a sensor arrangement 700 and FIG7( b) shows a cross-sectional side view of the sensor arrangement 700, the sensor arrangement 700 comprising a central horizontal Hall element 701 and an integrated magnetic flux concentrator 711 aligned with the central horizontal Hall element 701, as described above. The sensor arrangement 700 further comprises a second integrated magnetic flux concentrator 712 in the shape of a ring. The ring 712 has an inner diameter greater than the outer diameter of the first magnetic flux concentrator 711 and is arranged concentrically with the first magnetic flux concentrator 711. The sensor arrangement 700 further comprises a second and a third horizontal Hall element 702, 703, which are arranged adjacent to the outer edge of the second magnetic flux concentrator 712 and on opposite sides of the second magnetic flux concentrator 712.

[0162] In the drawings, the height of the first magnetic concentrator 711 is shown to be greater than the height of the second magnetic concentrator 712 , but this is not absolutely required, and in other embodiments, the height of the first magnetic concentrator 711 may be equal to or lower than the height of the second magnetic concentrator 712 .

[0163] In a specific embodiment, the diameter of the first magnetic flux concentrator 711 is about 25μm±10μm, the inner diameter of the ring 712 is 40μm to 120μm, the outer diameter is 170μm to 250μm, the height of the first magnetic flux concentrator is 20μm to 60μm, and the height of the second magnetic flux concentrator 712 is 20μm to 30μm.

[0164] In a particular embodiment, the heights of the first and second iMFCs are equal and are in the range of 20 μm to 30 μm.This provides the advantage that both magnetic flux concentrators 711 , 712 can be formed simultaneously in the same processing step(s).

[0165] 7( b ) shows how the perpendicular magnetic field Bz is measured by the first horizontal Hall element Hc after being amplified by the first magnetic concentrator 711 , and shows how the substantially horizontal magnetic field Bx is measured by the horizontal Hall elements H1 and H3 after being amplified by the second magnetic concentrator 712 .

[0166] The measurement of the horizontal magnetic field component Bx using the ring-shaped flux concentrator is very similar to the measurement of the horizontal magnetic field component Bx using the disk-shaped flux concentrator.

[0167] Using the magnetic sensor structure 700, the horizontal magnetic field component Bx can be calculated, for example, as Bx=A*(H3-H1), where A is a predefined constant that (especially) depends on the characteristics of the second magnetic concentrator 712. The vertical magnetic field component Bz can be calculated, for example, as Bz=K*Hc, where K is a predefined constant that (especially) depends on the characteristics of the first magnetic concentrator 711 and the relative position of the horizontal Hall element Hc.

[0168] In an embodiment of the present invention (not shown), a sensor device (not shown) is provided, which has two magnetic structures as shown in Figure 7 (a), and a certain distance Δx between each other is in the range of 1.0mm to 2.5mm, or in the range of 1.5mm to 2.1mm, for example, equal to about 1.7mm, or equal to about 1.8mm, or equal to about 1.9mm. The first magnetic structure will provide magnetic field values ​​Bx1 and Bz1 at a first position X, and the second magnetic structure will provide magnetic field values ​​Bx2 and Bz2 at a second position X+Δx. The sensor device can be further configured to determine a first magnetic field gradient dBx / dx of the Bx component along the X direction and a second magnetic field gradient dBz / dx of the Bz component along the X axis, and can be further configured to determine a linear position or an angular position based on these gradients, for example according to the formula:

[0169] θ=atan2(dBx / dx,dBz / dx)[3]

[0170] The main advantage of this embodiment is that not only the Bx field can be passively amplified, but also the Bz field can be passively amplified. This can be particularly advantageous in systems where the Bz field is weaker than the Bx field.

[0171] FIG7(c) shows a magnetic sensor structure 750, which is a variation of the structure of FIG7(a) and has five horizontal Hall elements: a central Hall element Hc located below the first iMFC 751 and four horizontal Hall elements arranged at the edges of the ring-shaped iMFC 752. The structure 750 is capable of measuring three orthogonal magnetic field components Bx, By, and Bz at a specific location.

[0172] A linear or angular position sensor device (not shown) may include two magnetic sensor structures as shown in FIG7( c ), which are spaced a certain distance Δx in the X direction. Such a device is capable of measuring (Bx1, By1, Bz1) at a first sensor position X and (Bx2, By2, Bz2) at a second sensor position X+Δx, and may be configured to calculate three magnetic field gradients dBx / dx, dBy / dx, dBz / dx of the magnetic field components Bx, By, Bz in the X direction.

[0173] Another linear or angular position sensor device (not shown) may include at least three, for example four, magnetic sensor structures shown in FIG. 7( c ), two of which are spaced a certain distance Δx along the X direction, and the other two are spaced a certain distance Δy along the Y direction. Such a device is capable of measuring at least three, for example four, three-dimensional magnetic field vectors (Bx[i], By[i], Bz[i]), and may be configured to calculate six magnetic field gradients, including: dBx / dx, dBy / dx, dBz / dx along the X direction, and dBx / dy, dBy / dy, dBz / dy along the Y direction.

[0174] FIG8 (a) shows a top view of another magnetic sensor structure 800 proposed by the present invention that can measure three orthogonal magnetic field components Bx, By, and Bz. Structure 800 includes a central Hall element Hc and a first IMFC 811 located above and aligned with the central Hall element, and further includes four horizontal Hall elements H1-H4 and four radially extending elongated IMFC elements 812a-812d. The Hall elements H1-H4 are arranged near the edges of the corresponding iMFC elements. The sensor structure is capable of measuring Bx, By, and Bz at a single sensor position. A linear or angular sensor device may include at least one or at least two, or at least three or at least four such structures for measuring magnetic field vectors (Bx, By, Bz) at multiple positions, and may be suitable for calculating one or more (first-order or second-order) magnetic field gradients based thereon.

[0175] FIG8( b ) shows another magnetic sensor structure 850 in top view, which is a variation of the sensor structure 800 of FIG8( a ) and is also capable of measuring three orthogonal magnetic field components Bx, By, Bz at a single sensor location. It also includes four elongated magnetic concentrator elements 852a-852d and four horizontal Hall elements H1-H4. The sensor device may include at least one or at least two, or at least three or at least four such structures, and may be adapted to calculate one or more (first-order or second-order) magnetic field gradients based thereon.

[0176] FIG. 9( a ) is a schematic diagram of a sensor device 920 , which includes a semiconductor substrate having at least one magnetic sensor structure as described above.

[0177] FIG9( b) is a schematic diagram of a sensor device 970 comprising two semiconductor dies stacked on each other. In this example, the first semiconductor die 922 may or may not include a magnetic sensor element and may or may not include an integrated magnetic flux concentrator. The second semiconductor die 921 comprises a sensor arrangement as described above, including a horizontal Hall element Hc and a magnetic flux concentrator 911 aligned therewith. The two semiconductor dies can be interconnected in a known manner, for example by bonding wires. The advantage of using two separate semiconductor dies is that it allows the process of each semiconductor substrate to be optimized independently.

[0178] In a variant (not shown), the sensor device may include two separate semiconductor dies arranged side by side.

[0179] Fig.10 is a schematic diagram of a sensor device 1070 including a semiconductor substrate 1022. The semiconductor substrate 1022 includes a classical magnetic sensor structure (e.g., including an annular or disk-shaped IMC) and at least two horizontal Hall elements H1, H3 arranged near the edge of the IMC. The semiconductor substrate 1022 further includes an integrated magnetic flux concentrator 1011, which is aligned with the horizontal Hall element Hc, as described above. The main purpose of this figure is to show that a single semiconductor substrate can contain different types of integrated magnetic concentrators, with the same height or different heights.

[0180] In a variation of embodiment 1000, a classical sensor structure may include, for example

[0181] A plurality of radially oriented elongated IMC components, and a plurality of horizontal Hall elements disposed near edges of the elongated IMC components, such as elements similar to those shown in FIG. 8( a ) or FIG. 8( b ).

[0182] Fig.11A method for producing an integrated sensor device including a magnetic sensor structure as described above (see, for example, FIG. 2( c ) or FIG. 3 ) is shown. Figure 4(a) to Figure 4(c) ), and Fig.12 The intermediate structures obtained in the various steps of the method are shown. The method comprises the following steps:

[0183] a) providing 1101 a semiconductor substrate including a horizontal Hall element;

[0184] Fig.12 An example of such a substrate is shown in (a). The substrate may be a CMOS substrate comprising a semiconductor material (e.g., Si or GaAs) having an active surface in which a horizontal Hall element 1201 is implemented. The substrate may also include an "interconnect stack" 1223 (also referred to as a "metal stack") comprising at least four metal layers separated by insulating layers. The substrate may further include a top layer 1224, such as a passivation layer, for example comprising or consisting of silicon oxide or silicon nitride.

[0185] b) providing 1102 a photoresist layer 1225 on top of the semiconductor substrate;

[0186] Providing the photoresist layer may be done, for example, by spin coating.

[0187] c) forming 1103 an opening 1226 or a cavity in the photoresist layer 1225 such that the center of the opening 1226 or the cavity is substantially aligned with the center of the horizontal Hall element 1201 and such that a height (H) of the opening measured in a Z direction perpendicular to the semiconductor substrate is at least 25% of a lateral dimension (D) of the opening measured in a direction parallel to the semiconductor substrate (e.g., X or Y);

[0188] For example, an opening may be formed in the photoresist layer 1255 by photolithography. The height of the opening may be defined by the height of the photoresist layer 1225. The lateral dimensions of the opening may be defined by the pattern. The bottom surface area of ​​the opening 1226 may be greater than, substantially equal to, or less than the area of ​​the horizontal Hall element 1201. Fig.12 An example of a substrate obtained after performing steps b) and c) is shown in (b).

[0189] d) depositing 1104 a soft magnetic material within the opening or cavity to form an integrated magnetic concentrator in a shape having a height (H) and a lateral dimension (D), wherein the height is at least 50% of the lateral dimension.

[0190] For example, the soft magnetic material may be deposited by electroplating. The soft magnetic material may be Fe, Ni, FeNi, Fe-based alloys, Ne-based alloys or FeNi-based alloys.

[0191] Fig.12 An example of a substrate obtained after performing step d) is shown in (c).

[0192] The method may further comprise an optional step e) after step d) of removing 1105 the photoresist layer 1225 .

[0193] Fig.12 An example of a substrate obtained after performing step e) is shown in (d).

[0194] Of course, depending on the specific implementation, the method may include further steps, for example, providing a seed layer before performing electroplating. These steps and their purposes are well known in the art and therefore do not need to be explained in more detail here.

[0195] In a variant of the method, step c) comprises forming openings with H / D>30%, or H / D>40%, or H / D>50%, or H / D>60% or H / D>70%.

[0196] Fig.13 It shows that Fig.11 Intermediate structures obtained by variations of the method shown.

[0197] Fig.13 The intermediate structure shown in (a) is similar to Fig.12 (a) The intermediate structure comprises a semiconductor substrate having an active surface and a horizontal Hall element 1301 , and comprises an interconnect stack 1323 and a passivation layer 1324 .

[0198] Fig.13 The intermediate structure shown in (b) can be obtained by Fig.13 (a) is obtained by providing a photoresist layer 1325 on the substrate and forming an opening 1326 in the photoresist layer 1325 (for example, by patterning and etching).

[0199] However, contrary to what is usually done in the prior art, the opening 1326 is made so that it partially penetrates the interior of the interconnect stack 1323. This can be achieved by partially etching one or more isolation layers and / or metal layers of the interconnect stack 1323. Fig.13 In the specific example of (b), the interconnect stack 1323 includes four metal layers M1, M2, M3, M4, and the opening 1326 extends to abut against a metal etching stopper 1328 provided in the third metal layer M3, but the present invention is not limited thereto, and in a variant, the metal etching stopper may be provided in another metal layer or even omitted. When omitted, the depth of the opening may be determined by the timing of the etching process, in a manner known in the art.

[0200] Fig.13The structure shown in (c) may be obtained by depositing a soft magnetic material (eg a ferromagnetic material) in the opening or cavity 1327, for example by electroplating.

[0201] Fig.13 The structure shown in (d) can be obtained by removing the photoresist layer, which is optional.

[0202] Interested readers can find more variations and / or more details on how the openings in the interconnect layer 1323 are made in the co-pending patent application EP19176438.0 filed by the same applicant on May 24, 2019, which is incorporated herein by reference in its entirety. All techniques and materials mentioned in this earlier EP application are also contemplated as possible variations or enhancements of the methods described herein.

[0203] Fig.13 (c) Structure and Fig.12 The main difference between the structures of (c) is that the magnetic flux concentrator 1327 is located closer to the Hall element 1301, so the distance "d" between the Hall element and the bottom surface of the magnetic flux concentrator 1327 is reduced, which may be beneficial to the magnetic gain Gz.

[0204] Although the original question (such as Figure 1 2) and the solution proposed in FIG. 2 are related to a sensor device having four horizontal Hall elements, but the invention is of course not limited to devices having four horizontal Hall elements, but is also applicable to a sensor device having at least one horizontal Hall element and an iMFC aligned therewith. The following is provided for completeness and will not be described in detail.

[0205] Fig.14 (a) and Fig.14 (b) shows another embodiment of the magnetic sensor structure, which includes two magnetic sensor structures as shown in FIG. 2(c) or Figure 4(a) to Figure 4(c) The structure shown is separated by a distance Δx along the axis, in perspective view and top view respectively. The structure can measure Bz1, Bz2 and dBz / dx. The structure can be used in a current sensor device, for example.

[0206] Fig.15 (a) is composed of three as shown in Figure 2(c) or Figure 4(a) to Figure 4(c) A top view of the magnetic sensor structures of the structure shown are equally spaced along the axis.

[0207] Fig.15 (b) is a linear position sensor including a multi-pole magnetic structure and Fig.15 (a) Schematic diagram of the magnetic sensor structure shown.

[0208] Fig.15(c) is an angular position sensor comprising a quadrupole annular magnet and Fig.15 (a) shows the off-axis magnetic sensor structure.

[0209] Fig.15 (d) shows Fig.15 A variation of the magnetic sensor structure of (a), in which the sensor elements are located on a triangle, can be used in linear or angular position sensor systems.

[0210] Fig.15 (e) shows Fig.15 A variation of the magnetic sensor structure of (a), comprising four sensor elements equidistantly spaced along the axis, can be used in linear or angular position sensor systems.

[0211] Fig.15 (f) shows Fig.15 A variation of the magnetic sensor structure of (a), which contains four sensor elements located on a trapezoid, can be used in linear or angular position sensor systems.

[0212] Interested readers can find more details on how to derive the angular or linear position from the sensor signal in patent application EP20173760.8, which was filed by the same applicant on May 8, 2020 and is incorporated herein by reference, so there is no need to repeat it here.

[0213] Fig.16 (a) and Fig.16 (b) Variations of the magnetic sensor structure of FIG. 2( a ) are shown in perspective and top view, including three sensor structures shown in FIG. 2( c ) located on an imaginary circle and spaced angularly at multiples of 120°.

[0214] Fig.16 (c) shows the Fig.16 (a) and Fig.16 (b) shows an angle sensor device 1620 of a magnetic sensor structure, and an angle system 1650 including the sensor device 1620 and further including a dipole magnet. Fig.16 In the embodiment shown in (c), the magnet is a bipolar disc magnet, but the present invention is not limited thereto, and other bipolar magnets may also be used, such as a bipolar ring magnet or a bipolar rod magnet.

[0215] Similar sensor devices, but without an integrated flux concentrator, are known in the art and therefore do not need to be described in more detail here. It can be said that the three Hall elements sense the magnetic field provided by the magnet as three sinusoidal signals which are phase-shifted by 120°, from which an angular position signal can be derived.

[0216] Fig.17(a) and Fig.17 (b) shows the perspective view and the top view of FIG. 2(a) and Fig.16 (a) of the magnetic sensor structure, including six Figure 2 (c) or Figure 4(a) to Figure 4(c) The sensor configuration shown is located on an imaginary circle and spaced at angles in multiples of 60°.

[0217] Fig.17 (c) shows the Fig.17 (a) and Fig.17 (b) shows an angle sensor device 1720 of a magnetic sensor structure, and an angle system 1750 including the sensor device 1720 and further including a quadrupole magnet. Fig.17 In the embodiment shown in (c), the quadrupole magnet is a quadrupole disc magnet, but the present invention is not limited thereto, and other quadrupole magnets, such as a quadrupole ring magnet, may also be used.

[0218] It can be clearly seen from the above that Figure 2(c) or Figure 4(a) to Figure 4(c) The magnetic sensor structure shown in can be used for all current solutions using horizontal Hall without integrated flux concentrators and serves the same purpose (measuring the magnetic field component perpendicular to the semiconductor substrate) but with an improved signal-to-noise ratio (SNR).

[0219] Reference numerals:

[0220] In different embodiments, similar elements generally have similar reference numbers, differing by multiples of 100.

[0221] -00: Magnetic sensor arrangement

[0222] -01: ​​(First) Horizontal Hall Element

[0223] -02: Second level Hall element

[0224] -03: The third level Hall element

[0225] -04: The fourth level Hall element

[0226] -05: The fifth level Hall element

[0227] -10: Magnetic sensor structure

[0228] -11: (First) Magnetic Concentrator

[0229] -12: Second magnetic concentrator

[0230] -20: Sensor equipment

[0231] -21: (First) Semiconductor Substrate / Semiconductor Die

[0232] -22: Second semiconductor substrate / semiconductor die

[0233] -23: Interconnect Stacking

[0234] -24: Top layer, such as passivation layer

[0235] -25: Photoresist

[0236] -26: opening or cavity

[0237] -27: Magnetic materials

[0238] -28: Side stopper

[0239] -29: vertical axis

[0240] M1, M2, M3, M4: first, second, third, fourth metal layer

Claims

1. An integrated sensor device, comprising: A semiconductor substrate including a first horizontal Hall element; a first integrated magnetic flux concentrator, located above the first horizontal Hall element; wherein the first integrated magnetic flux concentrator has a shape whose geometric center is vertically aligned with the geometric center of the first horizontal Hall element in a direction perpendicular to the semiconductor substrate; wherein the shape has a height in a direction perpendicular to the semiconductor substrate and has a maximum lateral dimension in a direction parallel to the semiconductor substrate; wherein the height of the first integrated magnetic flux concentrator is in the range from 30 μm to 500 μm, and / or wherein a ratio of the height to the maximum lateral dimension of the first integrated magnetic flux concentrator is at least 25%, and Wherein, the integrated sensor device is a semiconductor die or a chip package.

2. The integrated sensor device according to claim 1, in, The shape of the first integrated magnetic flux concentrator is an overall cylindrical shape, or an overall conical shape, or an overall truncated conical shape, or a rotationally symmetrical shape, or a circularly symmetrical shape around the longitudinal axis, or the first integrated magnetic flux concentrator has an overall prismatic shape, and the overall prismatic shape has a regular polygonal cross-section, or the first integrated magnetic flux concentrator has an overall mushroom shape, or includes a cylindrical portion, or includes a conical portion, or includes a truncated conical portion.

3. The integrated sensor device according to claim 2, in, The overall conical shape or the overall truncated conical shape or the conical portion or the truncated conical portion tapers toward the first horizontal Hall element.

4. The integrated sensor device according to claim 1, in, The shape of the first integrated magnetic flux concentrator has a diameter or a maximum diagonal in a cross-section on a plane parallel to the semiconductor substrate, and the diameter or the maximum diagonal ranges from 15μm to 40μm, or from 15μm to 35μm, or from 16μm to 34μm, or from 17μm to 33μm, or from 18μm to 32μm, or from 19μm to 31μm, or from 20μm to 30μm.

5. The integrated sensor device according to claim 1, in, The orthogonal projection of the first horizontal Hall element on the semiconductor substrate is completely located within the edge of the orthogonal projection of the bottom surface of the first integrated magnetic flux concentrator on the semiconductor substrate; or wherein an orthogonal projection of the bottom surface of the first integrated magnetic flux concentrator on the semiconductor substrate is completely located within an edge of an orthogonal projection of the first horizontal Hall element on the semiconductor substrate; or The edge of the orthogonal projection of the first horizontal Hall element on the semiconductor substrate intersects with the edge of the orthogonal projection of the bottom surface of the first integrated magnetic flux concentrator on the semiconductor substrate.

6. The integrated sensor device according to claim 1, in, The sensor device is a current sensor device, or wherein the sensor device is a linear position sensor device; or Wherein, the sensor device is an angular position sensor device.

7. The integrated sensor device according to claim 1 in, A distance between the first horizontal Hall element and the first integrated magnetic flux concentrator is a value ranging from 1 μm to 20 μm.

8. The integrated sensor device according to claim 1, in, The semiconductor substrate includes an interconnect stack including at least four metal layers separated by a plurality of insulating layers; and Wherein, at least a portion of the first integrated magnetic flux concentrator is located within the interconnect stack.

9. The integrated sensor device according to claim 1, in, The semiconductor substrate has an active surface including the first horizontal Hall element and has a passive surface; and Wherein, the first integrated magnetic flux concentrator is located on the side of the active surface.

10. The integrated sensor device according to claim 1, in, The semiconductor substrate has an active surface including the first horizontal Hall element and has a passive surface; and Wherein, the first integrated magnetic flux concentrator is located on a side of the passive surface.

11. The integrated sensor device according to claim 1, Also included is a second integrated magnetic flux concentrator having an annular shape having an inner diameter greater than an outer diameter of the first integrated magnetic flux concentrator and arranged concentrically with the first integrated magnetic flux concentrator; and wherein the semiconductor substrate further comprises at least a second horizontal Hall element and a third horizontal Hall element, and the second horizontal Hall element and the third horizontal Hall element are arranged near an edge of the second integrated magnetic flux concentrator; or Also included is a plurality of second integrated flux concentrators, each of the plurality of second integrated flux concentrators having an elongated shape and being radially oriented relative to the first horizontal Hall element; and The semiconductor substrate further includes a plurality of further horizontal Hall elements, which are arranged near edges of corresponding second integrated magnetic flux concentrators.

12. The integrated sensor device according to claim 1, in, The semiconductor substrate further includes a second integrated magnetic flux concentrator having a ring shape or a disk shape, and further includes at least a second horizontal Hall element and a third horizontal Hall element, wherein the at least second horizontal Hall element and the third horizontal Hall element are arranged near an edge of the second integrated magnetic flux concentrator; or The semiconductor substrate further comprises a plurality of second integrated magnetic flux concentrators having an elongated shape, and further comprises a plurality of horizontal Hall elements, each of the plurality of horizontal Hall elements being arranged near an edge of a corresponding elongated shape.

13. The integrated sensor device of claim 1, Also included is a second semiconductor substrate; in, The second semiconductor substrate includes a second integrated magnetic flux concentrator having a ring shape or a disk shape, and further includes at least a second horizontal Hall element and a third horizontal Hall element, the second horizontal Hall element and the third horizontal Hall element being arranged near an edge of the second integrated magnetic flux concentrator; or wherein the second semiconductor substrate comprises a plurality of second integrated magnetic flux concentrators having an elongated shape, and further comprises a plurality of horizontal Hall elements, each of the plurality of horizontal Hall elements being arranged near an edge of a corresponding elongated shape; and The semiconductor substrate and the second semiconductor substrate are stacked on top of each other or adjacent to each other and are interconnected by bonding wires.

14. A method for producing an integrated sensor device, comprising the steps of: a) providing a semiconductor substrate including a first horizontal Hall element; b) providing a photoresist layer on top of the semiconductor substrate; c) forming an opening or a cavity in the top layer of the semiconductor substrate such that the center of the opening or the cavity is vertically aligned with the center of the first horizontal Hall element in a direction perpendicular to the semiconductor substrate; d) providing a soft magnetic material in the opening or the cavity so that the first integrated magnetic flux concentrator has a shape along an axis perpendicular to the semiconductor substrate and passing through the first horizontal Hall element and has a maximum lateral dimension in a direction parallel to the semiconductor substrate; wherein the first integrated magnetic flux concentrator has a height in a direction perpendicular to the semiconductor substrate, the height being in the range from 30 μm to 500 μm, and / or wherein a ratio of the height to the maximum lateral dimension of the first integrated magnetic flux concentrator is at least 25%, and Wherein, the integrated sensor device is a semiconductor die or a chip package.

15. The method of claim 14, Wherein step a) comprises: providing a semiconductor substrate including a first horizontal Hall element and including an interconnect stack including at least four metal layers separated by a plurality of insulating layers; and Wherein step b) comprises: removing at least a portion of at least one of the insulating layers.

16. An integrated sensor device comprising: A semiconductor substrate including a first horizontal Hall element; a first integrated magnetic flux concentrator, located above the first horizontal Hall element; wherein the first integrated magnetic flux concentrator is coaxial with the first horizontal Hall element in a direction perpendicular to the semiconductor substrate; wherein a height of the first integrated magnetic flux concentrator in a direction perpendicular to the semiconductor substrate is in the range from 30 μm to 500 μm, and / or wherein a ratio of the height of the first integrated magnetic flux concentrator to its maximum lateral dimension in a direction parallel to the semiconductor substrate is at least 25%, and Wherein, the integrated sensor device is a semiconductor die or a chip package.

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