JP2006064530A - Magnetic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic sensor which improves the convergence efficiency of magnetic flux with respect to a magneto-electric transducer. <P>SOLUTION: The magnetic sensor comprises the magneto-electric transducer 5 formed on a first principal surface U of an SOI layer 4 and magnetic bodies 6, 7 which are formed on the opposite sides across the magneto-electric transducer 5 on the same plane on the first principal surface U. The magnetic bodies 6, 7 are formed so that their width in the direction perpendicular to the opposite direction of the magnetic bodies 6, 7 extends as they become more distant from the magneto-electric transducer 5. Low-magnetic-permeability sections 8, 9, of which the magnetic permeability is lower than that of air, are formed on the opposite sides across the magneto-electric transducer 5 in the direction perpendicular to the opposing direction of the magnetic bodies 6, 7 on the first principal surface U. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic sensor that detects magnetism, and more particularly to a magnetic sensor that is used in an electronic compass or the like to detect geomagnetism.

  In recent years, there has been an increasing demand for a portable GPS terminal device that can acquire position information using a GPS (Global Positioning System). Accordingly, demand for an electronic compass for detecting the direction (azimuth) of the GPS terminal device is increasing. The electronic compass requires a small magnetic sensor capable of detecting magnetic fields in three orthogonal directions in order to detect geomagnetism regardless of the attitude of the GPS terminal device.

  As this type of magnetic sensor, for example, as disclosed in Patent Document 1, a sensor including a Hall element and a magnetic flux focusing element that focuses a magnetic flux on the Hall element is known. FIG. 14 is a view showing a conventional magnetic sensor described in Patent Document 1, FIG. 14 (a) is a longitudinal sectional view of this magnetic sensor, and FIG. 14 (b) is a view of the same device viewed from the back side. FIG. 15 is a perspective view and FIG. 15 is an explanatory view of the operation of the apparatus. In this magnetic sensor 150, a Hall element 115 that is a magnetoelectric conversion element is formed on a first main surface 113 of a semiconductor substrate 111 that uses silicon as a base material, and the Hall element 115 on the second main surface 117 side. An etching groove 119 having a trapezoidal vertical cross section reaching the vicinity of the Hall element 115 is formed at a portion facing the hole element 115. The etching groove 119 has a rectangular bottom surface 120 facing the hall element 115 and four trapezoidal inclined surfaces surrounding the bottom surface 120. That is, the etching groove 119 is formed in a tapered shape so that the diameter becomes smaller as it approaches the bottom surface 120 from the second main surface 117. In the etching groove 119, a magnetic part 121 made of a high permeability material such as permalloy or ferrite is embedded in order to focus an external magnetic field on the Hall element 115. Further, an insulating film 125 is formed on the first main surface 113 of the semiconductor substrate 111, and a magnetic film 127 is stacked at a position facing the Hall element 115 through the insulating film 125. Is formed.

  In the magnetic sensor 150 configured as described above, the Hall voltage output from the Hall element 115 is the normal direction Z of the first main surface 113 and the second main surface 117 of the semiconductor substrate 111, that is, the sensitivity axis of the Hall element 115. When the external magnetic field H is directed in the direction, the Hall element 115 exhibits the maximum sensitivity. In general, the Hall voltage output from the Hall element 115 is proportional to the component in the normal direction Z of the external magnetic field H. Therefore, when the external magnetic field H is a magnetic field having a certain direction and strength as in the case of geomagnetism, the Hall voltage changes as the angle θ at which the external magnetic field H intersects the normal direction Z changes. It changes in proportion to H · cos θ. Therefore, the direction θ of the external magnetic field H can be detected by measuring the Hall voltage.

However, the strength of the magnetic field due to geomagnetism is about 0.3 gauss (= 3 × 10 ⁻⁵ Tesla) in Tokyo, which is relatively small with respect to the detection sensitivity of the Hall element 115. Therefore, in order to increase the detection accuracy, it is necessary to increase the magnetic flux density that passes through the Hall element 115. In the magnetic sensor 150 shown in FIG. 14, by providing the magnetic body portion 121 and the magnetic body film 127 that face each other in the sensitivity axis direction of the Hall element 115, the magnetic material absorbs magnetic flux so that the magnetic material absorbs an external magnetic field as shown in FIG. 15. Utilizing the property of convergence, the magnetic flux density passing through the Hall element portion 115 is made higher than the magnetic flux density due to the external magnetic field H, thereby improving the sensitivity of the Hall element 115 as a magnetic detection element. The magnetic sensor 150 also has an advantage that the etching groove 119 can be easily formed by performing anisotropic etching using the plane orientation of the single crystal silicon substrate.
Japanese Patent Laid-Open No. 11-261131

  However, in the magnetic sensor 150 described above, since the etching groove 119 is formed in a tapered trapezoidal shape that reaches the vicinity of the Hall element portion, the etching groove 119 is inclined without passing through the bottom surface 120 of the etching groove 119 facing the Hall element 115. The magnetic flux passing through the surface (leakage magnetic flux 128) increases. That is, there is a problem that a part of the magnetic flux converged by the magnetic body part 121 easily leaks without passing through the Hall element 115, and the effect of converging the magnetic flux is small compared to the chip size.

  The present invention has been made in view of such a problem, and an object thereof is to provide a magnetic sensor capable of improving the convergence efficiency of magnetic flux with respect to a magnetoelectric conversion element.

  In order to achieve the above object, a magnetic sensor according to the first means of the present invention includes a flat substrate, a magnetoelectric conversion element formed on one surface of the substrate, and the same plane on one surface of the substrate. First and second magnetic parts formed opposite to each other with the magnetoelectric conversion element sandwiched therebetween, wherein the first and second magnetic parts are respectively separated from the magnetoelectric conversion element. As the distance increases, the width in the direction perpendicular to the facing direction increases, and both sides of the magnetoelectric conversion element are sandwiched in the direction perpendicular to the facing direction in the first and second magnetic parts on one side of the substrate. The first and second low magnetic permeability portions having a lower magnetic permeability than air, which are formed opposite to each other, are further provided.

  In the above-described magnetic sensor, a third low magnetic permeability portion having a lower magnetic permeability than air is provided on the surfaces of the first and second magnetic body portions.

  Further, the magnetic sensor according to the second means of the present invention includes a flat substrate, a magnetoelectric conversion element formed on one surface of the substrate, and a surface facing the one surface of the substrate in the thickness direction. A support portion formed to form a recess, a fourth low permeability portion having a lower permeability than air, formed on the surface of the peripheral wall portion in the recess, and the first on the opposing surface of the substrate. 4 is formed so as to be connected to the low-permeability portion 4 so as to cover the fifth low-permeability portion having a lower magnetic permeability than air, the fourth and fifth low-permeability portions, and the bottom portion of the recess. A third magnetic body portion formed, and the magnetoelectric conversion element is provided at a position facing the bottom portion.

  Moreover, in the above-described magnetic sensor, a sixth low magnetic permeability portion having a magnetic permeability lower than that of air is formed in a region excluding the region where the magnetoelectric conversion element is formed on one surface of the substrate. It is characterized by that.

  And in the above-mentioned magnetic sensor, the 4th magnetic body part is formed so that the surface of the said 6th low magnetic permeability part and the surface of the said magnetoelectric conversion element may be covered.

  Furthermore, in the above-described magnetic sensor, the magnetic permeability of a region other than a region sandwiched between the bottom of the concave portion and the magnetoelectric conversion element in the substrate is lower than that of air.

  The magnetic sensor according to the third means of the present invention includes a flat substrate, a first magnetic sensor formed on one surface of the substrate, and a second magnet formed in the thickness direction of the substrate. A magnetic sensor, wherein the first magnetic sensor and the second magnetic sensor are the above-described magnetic sensors.

  And in the above-mentioned magnetic sensor, the said low-permeability part is comprised using the polyimide, It is characterized by the above-mentioned.

  In the magnetic sensor having such a configuration, the first and second magnetic body portions are formed as the first and second magnetic body portions formed opposite to each other on both sides of the magnetoelectric conversion element move away from the magnetoelectric conversion element. The air is formed so that the width in the direction perpendicular to the opposite direction of the first and second magnetic body portions is widened, and the air is formed opposite to each other with the magnetoelectric conversion element sandwiched in the direction perpendicular to the opposite direction in the first and second magnetic body portions. Since the first and second low magnetic permeability portions having lower magnetic permeability are further provided, the first and second magnetic body portions provided on both sides of the magnetoelectric conversion element allow the first and second magnetic body portions to be The magnetic flux passing through the magnetic body portion is converged on the magnetoelectric conversion element, and the generation of leakage magnetic flux that does not pass through the magnetoelectric conversion element is suppressed by the first and second low permeability portions, so that the magnetic flux converges on the magnetoelectric conversion element. Efficiency can be improved.

  In addition, the magnetic sensor having such a configuration includes a recess formed in the thickness direction from an opposing surface facing one surface of the substrate on which the magnetoelectric conversion element is formed, and an air formed on the peripheral wall surface in the recess. A third low magnetic permeability portion having a lower magnetic permeability than the air, and a fourth low magnetic permeability portion having a lower magnetic permeability than air formed on the opposing surface of the substrate in connection with the third low magnetic permeability portion, The third and fourth low magnetic permeability portions and a third magnetic body portion formed so as to cover the bottom portion of the concave portion, and the magnetoelectric conversion element is provided at a position facing the bottom portion of the concave portion. Therefore, the magnetic flux is converged on the bottom of the recess closest to the magnetoelectric conversion element by the third magnetic body portion, and the magnetic flux is converged on the magnetoelectric conversion element, and other than the bottom of the recess by the third and fourth low permeability portions. Magnetic flux leakage efficiency from the magnetoelectric transducer is reduced. It is possible to above.

  In the magnetic sensor having such a configuration, the first magnetic sensor for converging the magnetic flux in the direction parallel to the one surface of the substrate and the second magnetic sensor for converging the magnetic flux in the thickness direction of the substrate are on the same substrate. Therefore, the magnetic sensor having sensitivity in a plurality of axial directions can be reduced in size.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

(First embodiment)
FIG. 1 is a perspective view showing an example of the configuration of the magnetic sensor 1 according to the first embodiment of the present invention. 2A is a top view of the magnetic sensor 1 shown in FIG. 1, FIG. 2B is an XX ′ sectional view, and FIG. 2C is a YY ′ sectional view.

  A magnetic sensor 1 shown in FIG. 1 includes, for example, an SOI (Semiconductor On Insulator) layer 4 and a buried oxide film layer 3 in order from a first main surface U (upper surface in FIG. 1) side of a flat semiconductor substrate, for example, a silicon substrate. And an SOI substrate S on which the support layer 2 is formed. On the first main surface U side of the SOI layer 4, for example, a magnetoelectric conversion element 5 which is a Hall element is formed. This magnetoelectric conversion element 5 detects a change in current depending on the direction and magnitude of the applied magnetic field, and the sensitivity axis of the magnetoelectric conversion element 5 is in one direction along the main surface of the SOI substrate (hereinafter referred to as the X-axis direction). Is set).

  Further, the SOI layer 4 is selectively removed around the magnetoelectric conversion element 5 by etching until the buried oxide film layer 3 is reached by etching, and the magnetoelectric conversion element 5 is placed on the buried oxide film layer 3 in the same plane. A magnetic body portion 6 (first magnetic body portion) and a magnetic body portion 7 (second magnetic body portion) are formed facing each other on both sides. As a material for the magnetic parts 6 and 7, a conventionally known high magnetic permeability material such as permalloy or ferrite can be used.

  The magnetic body portions 6 and 7 converge the magnetic flux penetrating the magnetoelectric conversion element 5 from the outside. The magnetic body portions 6 and 7 have opposed surfaces 61 and 71 that are in contact with the magnetoelectric conversion element 5 and face each other with the magnetoelectric conversion element 5 sandwiched from both sides. The magnetic body portion 6 and the magnetic body portion 7 are closest to each other on the facing surface 61 and the facing surface 71. Further, the magnetic body portion 6 and the magnetic body portion 7 each have a width in a direction (hereinafter referred to as a Y-axis direction) perpendicular to the sensitivity axis direction (X-axis direction) of the magnetoelectric conversion element 5 as the distance from the magnetoelectric conversion element 5 increases. Is formed to expand.

  Further, on the first main surface U side of the SOI layer 4, one of the side surfaces of the magnetoelectric conversion element 5 that do not face the facing surfaces 61 and 71, and the slope formed so that the magnetic body portions 6 and 7 spread obliquely. The SOI layer 4 is selectively removed by etching in a region in contact with the surface until reaching the buried oxide film layer 3, and on the buried oxide film layer 3, one side surface of the magnetoelectric conversion element 5, The low magnetic permeability part 8 which is an example of a 1st low magnetic permeability part is formed so that the inclined surface formed so that it may spread diagonally of the magnetic body parts 6 and 7 may be contacted.

  Similarly, on the first main surface U side of the SOI layer 4, the other side surface of the magnetoelectric conversion element 5 that does not face the facing surfaces 61 and 71, and the slope formed so that the magnetic body portions 6 and 7 spread obliquely. The SOI layer 4 is selectively removed by etching in a region in contact with the surface until reaching the buried oxide film layer 3, and the other side surface of the magnetoelectric conversion element 5 is formed on the buried oxide film layer 3, A low-permeability portion 9, which is an example of a second low-permeability portion, is formed so as to be in contact with the inclined surface formed so as to extend obliquely of the magnetic body portions 6, 7, and is formed on the buried oxide film layer 3. The low magnetic permeability portions 8 and 9 are formed so as to oppose each other with the magnetoelectric conversion element 5 and the magnetic body portions 6 and 7 sandwiched from both sides in the Y-axis direction.

  Further, the low magnetic permeability portions 8 and 9 are made of a material having a low magnetic permeability that is less than 1.0 H / m, which is the magnetic permeability of air, such as polyimide having a non-magnetic permeability of 0.005 or air. It is formed by sticking low composition glass or the like to a semiconductor substrate.

  Next, the operation of the magnetic sensor 1 configured as described above will be described. In FIG. 2A, the magnetic flux B when the magnetic sensor 1 is placed so that the geomagnetic field is along the X-axis direction is indicated by a broken line. The magnetic flux B has a property of selectively passing through a path having the smallest magnetic resistance. In the magnetic sensor 1, the magnetic body portions 6 and 7 form a region having a much higher magnetic permeability than in the air, and the magnetic body portions 6 and 71 are formed on the pair of facing surfaces 61 and 71 facing each other with the magnetoelectric conversion element 5 interposed therebetween. 7 has the smallest distance, so that the magnetic resistance is the smallest in the path passing through the opposing surfaces 61 and 71 in the magnetic body portions 6 and 7, that is, the path passing through the magnetoelectric transducer 5.

  Accordingly, as shown in FIG. 2A, the magnetic flux B crosses the magnetic flux B in the direction perpendicular to the facing direction of the facing surfaces 61 and 71, that is, in the sensitivity axis direction of the magnetoelectric converting element 5, as it moves away from the magnetoelectric converting element 5. The magnetic body parts 6 and 7 formed so as to spread in the direction converge the magnetic flux B on the magnetoelectric transducer 5. Further, the low magnetic permeability portions 8 and 9 are formed so as to oppose each other with the magnetoelectric conversion element 5 and the magnetic body portions 6 and 7 sandwiched from both sides in the Y-axis direction. As a result of increasing the magnetic resistance of the path passing through the surface, the leakage magnetic flux passing through the inclined surfaces of the magnetic bodies 6 and 7 without passing through the opposing surfaces 61 and 71 is reduced, and the magnetic flux B with respect to the magnetoelectric transducer 5 is reduced. Convergence efficiency can be improved and the magnetic sensitivity of the magnetic sensor 1 can be improved.

  The magnetic sensor 1 may be configured not to include the low magnetic permeability portions 8 and 9. FIG. 3 is a top view showing the path of the magnetic flux B when the magnetic sensor 1 does not include the low magnetic permeability portions 8 and 9. As shown in FIG. 3, even when the low magnetic permeability portions 8 and 9 are not provided, the magnetic resistance in the path passing through the opposing surfaces 61 and 71 in the magnetic body portions 6 and 7, that is, the path passing through the magnetoelectric transducer 5. , The magnetic flux B is converged on the magnetoelectric transducer 5 as shown in FIG. However, in the case where the low magnetic permeability portions 8 and 9 are not provided, as shown in FIG. 3, the magnetic material is formed on the same plane as the magnetoelectric conversion element 5 and the magnetic material portions 6 and 7 formed in the SOI layer 4. Since the leakage magnetic flux 10 passing through the inclined surfaces of the parts 6 and 7 is generated and the convergence efficiency of the magnetic flux B is lowered, it is desirable to provide the low magnetic permeability parts 8 and 9.

(Second Embodiment)
Next, a magnetic sensor according to a second embodiment of the present invention will be described. FIG. 4 is a perspective view showing an example of the configuration of the magnetic sensor 1a according to the second embodiment of the present invention. 5A is a top view of the magnetic sensor 1a shown in FIG. 4, FIG. 5B is an XX ′ sectional view, and FIG. 5C is a YY ′ sectional view.

  The magnetic sensor 1a shown in FIG. 4 further includes low magnetic permeability portions 8 and 9 on the upper surfaces of the magnetic body portions 6 and 7, the magnetoelectric conversion element 5, and the low magnetic permeability portions 8 and 9 in the magnetic sensor 1 shown in FIG. The low magnetic permeability part 11 which is an example of the 3rd low magnetic permeability part comprised with the material of the low magnetic permeability whose magnetic permeability is less than 1.0 H / m which is the magnetic permeability of air is formed. . In FIG. 4, the magnetoelectric conversion element 5 and the magnetic body portions 6 and 7 are shown through the low magnetic permeability portion 11.

  Since the other configuration is the same as that of the magnetic sensor 1 shown in FIG. 1, the description thereof will be omitted, and the operation of the magnetic sensor 1a shown in FIG. 4 will be described below. FIG. 6 is a perspective view showing the leakage flux 12 in the case where the magnetic sensor 1a shown in FIG. As shown in FIG. 6, when the low magnetic permeability portion 11 is not provided, the normal direction of the first main surface U between the magnetic body portion 6 and the magnetic body portion 7 (hereinafter referred to as the Z-axis direction). In some cases, the leakage flux 12 is generated, and the convergence efficiency of the magnetic flux B to the magnetoelectric conversion element 5 is lowered.

  On the other hand, according to the magnetic sensor 1a shown in FIG. 4, the low magnetic permeability lower than that of air provided on the top surfaces of the magnetic body portions 6 and 7, the magnetoelectric conversion element 5, and the low magnetic permeability portions 8 and 9 is lower. Since the magnetic resistance in the Z-axis direction is increased by the portion 11 and the generation of the leakage magnetic flux 12 is reduced, the convergence efficiency of the magnetic flux B with respect to the magnetoelectric transducer 5 can be improved, and the magnetic sensitivity of the magnetic sensor 1a is improved. Can be made.

  In the present embodiment, an example in which the low magnetic permeability portion 11 is provided on the top surfaces of the magnetic body portions 6 and 7, the magnetoelectric conversion element 5, and the low magnetic permeability portions 8 and 9 has been described. The low magnetic permeability portion 11 may not be provided on the upper surfaces of the magnetic permeability portions 8 and 9, and the low magnetic permeability portion 11 may be formed only on the upper surfaces of the magnetic body portions 6 and 7.

(Third embodiment)
Next, a magnetic sensor according to a third embodiment of the present invention will be described. FIG. 7 is a perspective view showing an example of the configuration of the magnetic sensor 1b according to the third embodiment of the present invention. 8A is a top view of the magnetic sensor 1b shown in FIG. 7, FIG. 8B is an XX ′ sectional view, and FIG. 8C is a YY ′ sectional view.

  The magnetic sensor 1b shown in FIGS. 7 and 8 includes, for example, a flat semiconductor substrate, for example, a silicon substrate in order from the first main surface U (upper surface in FIG. 8) side, the SOI layer 4, the buried oxide film layer 3, and A SOI substrate S on which a support layer 2 that is a support portion is formed is provided, and a magnetoelectric conversion element 5 that is, for example, a Hall element is formed on the first main surface U side of the SOI layer 4. The sensitivity axis of the magnetoelectric transducer 5 is set in the normal direction of the first main surface U (hereinafter referred to as the Z-axis direction).

  Further, on the second main surface D side which is the lower surface of the support layer 2 facing the first main surface U, the support layer 2 is formed by ICP (inductively coupled plasma) etching using, for example, an oxide film having an opening as a mask. The recess 13 is formed by etching until the buried oxide film layer 3 is reached in the Z-axis direction from the two principal surfaces D. In FIG. 7, the figure which projected the recessed part 13 on the side surface of the support layer 2 is shown with the broken line. Further, the bottom surface 14 of the recess 13 is formed to be substantially flat, and the bottom surface 14 and the magnetoelectric conversion element 5 are arranged at positions facing each other with the buried oxide film layer 3 interposed therebetween. The area of the bottom surface 14 is equal to or less than the area of the sensitivity region, which is a region having magnetic detection sensitivity in the magnetoelectric conversion element 5.

  It is an example of the 4th and 5th low-permeability part by the material whose magnetic permeability is lower than air on the surface of the surrounding wall part in the recessed part 13 except the bottom face 14, and the surface of the 2nd main surface D in the support layer 2. A low magnetic permeability portion 15 is formed. Further, the magnetic body portion 16 (third portion) made of a material with high magnetic permeability is formed on the surface of the bottom surface 14 and the surface of the low magnetic permeability portion 15 formed on the peripheral wall portion of the recess 13 and the surface of the second main surface D. The magnetic body portion) is formed. The magnetic body portion 16 is formed to have a film thickness that facilitates the passage of magnetic flux in the plane of the magnetic body portion 16, and has a film thickness of, for example, about 2 to 5 μm.

  Further, on the first main surface U side of the SOI layer 4, the first main surface excluding a region (the upper surface of the magnetoelectric conversion element 5) that overlaps the magnetoelectric conversion element 5 in the normal direction (Z-axis direction) of the first main surface U. A low magnetic permeability portion 17 (sixth low magnetic permeability portion) is formed on the surface U (the surface of the SOI layer 4) with a material having a lower magnetic permeability than air. Further, on the first main surface U side, a magnetic body portion 18 (fourth magnetic body portion) made of a high magnetic permeability material is formed on the upper surface of the magnetoelectric conversion element 5 and the surface of the low magnetic permeability portion 17. Has been.

  The low magnetic permeability portions 15 and 17 are formed, for example, by attaching polyimide having non-magnetic permeability of 0.005, glass having a lower magnetic permeability than air, or the like to a semiconductor substrate, and further sputtering on the surface thereof, for example. The magnetic body portions 16 and 18 may be formed by forming ferrite.

  Here, as shown in FIGS. 8A and 8B, the magnetic part 18 is formed on the surface of the bottom surface 14 with the magnetoelectric conversion element 5 and the buried oxide film layer 3 interposed therebetween. Is formed in a shape that protrudes in a direction approaching the magnetic body portion 16 (downward in the Z-axis direction), and the distance between the magnetic body portion 16 and the magnetic body portion 18 is the shortest in the convex portion 19. ing. As a result, the magnetic resistance of the path from the convex portion 19 in the magnetic body portion 18 to the magnetic body portion 16 on the surface of the bottom surface 14 sandwiching the magnetoelectric conversion element 5 and the buried oxide film layer 3 is Z axis in the magnetic sensor 1b. The magnetic resistance is minimized in the direction.

  Next, the operation of the magnetic sensor 1b configured as described above will be described. FIG. 9 is a cross-sectional view taken along the line X-X ′ in FIG. 8A for explaining the operation of the magnetic sensor 1 b. FIG. 9 shows the magnetic flux B in a broken line when the magnetic sensor 1b is arranged in the magnetic field in the Z-axis direction. In the magnetic sensor 1b shown in FIG. 9, as described above, the magnetic flux B has a property of selectively passing through the path where the magnetic resistance becomes the smallest, so that the magnetic flux B converged by the magnetic body portion 18 has a magnetic resistance. It passes through the opposite portion between the low convex portion 19 and the magnetic body portion 16 on the surface of the bottom surface 14, that is, the magnetoelectric conversion element 5. Thereby, the magnetic flux B is converged on the magnetoelectric conversion element 5, and the convergence efficiency of the magnetic flux B on the magnetoelectric conversion element 5 can be improved.

  Further, when the magnetic sensor 1b is viewed in the Z-axis direction, portions other than the region where the magnetic body portion 16 and the magnetic body portion 18 face each other with the magnetoelectric conversion element 5 interposed therebetween are separated by the low magnetic permeability portions 15 and 17. Since the magnetic resistance in the axial direction is increased, the leakage magnetic flux that passes from the magnetic body portion 18 to the magnetic body portion 16 without passing through the magnetoelectric conversion element 5 is reduced. Efficiency can be improved and the magnetic sensitivity of the magnetic sensor 1b can be improved.

  In addition, although the example of the area of the bottom face 14 being equal to or less than the area of the sensitivity region in the magnetoelectric conversion element 5 has been shown, the area of the bottom face 14 is the magnetoelectric conversion element as shown in FIG. 5 and the projected area in the Z-axis direction of the magnetoelectric transducer 5 may be larger.

  For example, as shown in FIG. 16, in the magnetic sensor 150 according to the background art, when the area of the bottom surface 120 of the etching groove 119 is larger than the projected area of the hall element 115 in the Z-axis direction, The leakage magnetic flux 130 that passes through the magnetic sensor 150 without passing through the element 115 increases, and the convergence efficiency of the magnetic flux B on the magnetoelectric transducer 5 decreases.

  On the other hand, as shown in FIG. 10, when the area of the bottom surface 14 of the magnetic sensor 1 b is larger than the projected area in the Z-axis direction of the magnetoelectric transducer 5, the magnetic permeability from the bottom surface 14 is reduced by the low permeability portion 17. Since the magnetic resistance of the path that passes through the magnetic sensor 1b without passing through the conversion element 5 is increased, the occurrence of such leakage magnetic flux is reduced, and the area of the bottom surface 14 is the projected area of the magnetoelectric conversion element 5 in the Z-axis direction. Even in a larger configuration, the convergence efficiency of the magnetic flux B with respect to the magnetoelectric transducer 5 can be improved, and the magnetic sensitivity of the magnetic sensor 1b can be improved.

  In this case, the area of the bottom surface 14 can be made larger than the projected area in the Z-axis direction of the magnetoelectric conversion element 5, so that the processing accuracy of the recess 13 and the margin of alignment accuracy between the magnetoelectric conversion element 5 and the recess 13 are sufficient. The degree increases and the manufacture of the magnetic sensor 1b becomes easy.

(Fourth embodiment)
Next, a magnetic sensor according to a fourth embodiment of the invention will be described. 11A and 11B are diagrams showing an example of the configuration of a magnetic sensor 1c according to the fourth embodiment of the present invention. FIG. 11A is a top view, FIG. 11B is a cross-sectional view along XX ′, and FIG. 11 (c) is a YY ′ sectional view.

  The magnetic sensor 1c shown in FIG. 11 does not include the low magnetic permeability portions 15 and 17 from the magnetic sensor 1b shown in FIG. 7, and instead the support layer 2a and the SOI layer 4a are made of a material having lower magnetic permeability than air, For example, it is made of glass, polyimide, or the like having a lower magnetic permeability than air. Since the other configuration is the same as that of the magnetic sensor 1b shown in FIG. 7, the description thereof will be omitted, and the operation of the magnetic sensor 1c shown in FIG. 11 will be described below.

  FIG. 12 shows the magnetic flux B in a broken line when the magnetic sensor 1c is arranged in the magnetic field in the Z-axis direction. In such a configuration, the support layer 2a and the SOI layer 4a increase the magnetic resistance in the Z-axis direction instead of the low magnetic permeability portion 15 and the low magnetic permeability portion 17, and the support layer 2a and the SOI layer 4a have a low magnetic permeability. By constituting the magnetic permeability material, it becomes easy to increase the thickness of the low permeability layer whose permeability is lower than that of air. As a result, the magnetic resistance in the region excluding the magnetoelectric conversion element 5 is increased. The leakage magnetic flux passing through the region excluding the magnetic field can be reduced, the convergence efficiency of the magnetic flux B with respect to the magnetoelectric transducer 5 can be improved, and the magnetic sensitivity of the magnetic sensor 1c can be improved.

  Further, in the magnetic sensor 1c shown in FIG. 11, for example, an SOI layer 4, a buried oxide film layer 3, and a support layer 2 are formed in this order from the first main surface U side of a flat semiconductor substrate, for example, a silicon substrate. In the SOI substrate, the support layer 2 is polished up to the buried oxide film layer 3, and then the surface of the polished buried oxide film layer 3 and a glass substrate having a lower magnetic permeability than that of air are bonded with an adhesive member such as polyimide. If the glass substrate is used as the support layer 2a by combining, it can be manufactured using a semiconductor process.

  In the present embodiment, an example in which the area of the bottom surface 14 is larger than the projected area of the magnetoelectric conversion element 5 in the Z-axis direction is shown, but the area of the bottom surface 14 is equivalent to the area of the sensitivity region in the magnetoelectric conversion element 5. Or an area smaller than that.

  Further, for example, like the magnetic sensor 1d shown in FIG. 13, two magnetic sensors 1a (first magnetic sensors) shown in FIG. 4 and one magnetic sensor 1b (second magnetic sensor) shown in FIG. 7 are used. The magnetoelectric conversion elements 5 may be formed on the same semiconductor substrate in directions in which the sensitivity axes are orthogonal to each other. Further, the magnetic sensor 1 shown in FIG. 1 may be used instead of the magnetic sensor 1a shown in FIG. 4, and the magnetic sensor 1c shown in FIG. 11 may be used instead of the magnetic sensor 1b shown in FIG.

  In this case, magnetism in three orthogonal directions can be detected by using a single magnetic sensor 1d. Therefore, for example, a three-axis azimuth sensor used in an electronic compass can be configured by a single magnetic sensor 1d. . In addition, since the two magnetic sensors 1a and one magnetic sensor 1b can be formed on a single semiconductor substrate so that the sensitivity axes of the magnetoelectric transducer 5 are orthogonal to each other, the triaxial bearing sensor can be downsized. be able to.

It is a perspective view showing an example of composition of a magnetic sensor concerning a 1st embodiment of the present invention. (A) is a top view of the magnetic sensor shown in FIG. 1, (b) is an X-X ′ cross-sectional view, and (c) is a Y-Y ′ cross-sectional view. It is a top view which shows the modification of the magnetic sensor shown in FIG. It is a perspective view which shows an example of a structure of the magnetic sensor which concerns on the 2nd Embodiment of this invention. (A) is a top view of the magnetic sensor shown in FIG. 4, (b) is a cross-sectional view along X-X ′, and (c) is a cross-sectional view along Y-Y ′. It is a perspective view which shows the leakage magnetic flux in the magnetic sensor shown in FIG. It is a perspective view which shows an example of a structure of the magnetic sensor which concerns on the 3rd Embodiment of this invention. (A) is a top view of the magnetic sensor shown in FIG. 7, (b) is a cross-sectional view along X-X ′, and (c) is a cross-sectional view along Y-Y ′. FIG. 8 is an X-X ′ sectional view for explaining the operation of the magnetic sensor shown in FIG. 7. It is a figure which shows another example of the magnetic sensor shown in FIG. It is a figure which shows an example of a structure of the magnetic sensor which concerns on the 4th Embodiment of this invention, (a) is a top view, (b) is XX 'sectional drawing, (c) is YY' sectional drawing. It is. It is explanatory drawing for demonstrating operation | movement of the magnetic sensor shown in FIG. It is a perspective view which shows the modification of the magnetic sensor shown in FIG. 1, FIG. (A) is sectional drawing of the magnetic sensor which concerns on background art, (b) is a perspective view of the magnetic sensor which concerns on background art. It is explanatory drawing explaining operation | movement of the magnetic sensor which concerns on background art. It is explanatory drawing explaining operation | movement of the magnetic sensor which concerns on background art.

Explanation of symbols

1, 1a, 1b, 1c, 1d Magnetic sensor 2, 2a Support layer 3 Buried oxide film layer 4, 4a SOI layer 5 Magnetoelectric conversion element 6, 7, 8, 9, 11, 15, 17 Low magnetic permeability portion 13 Recessed portion 14 Bottom surface 16, 18 Magnetic body portion 19 Protrusion portion 61, 71 Opposing surface S SOI substrate D, U Main surface

Claims (8)

A flat substrate;
A magnetoelectric transducer formed on one surface of the substrate;
First and second magnetic parts formed opposite to each other with the magnetoelectric conversion element sandwiched in the same plane on one side of the substrate;
With
The first and second magnetic parts are formed such that the width in the direction perpendicular to the facing direction increases as the distance from the magnetoelectric conversion element increases.
A first lower permeability than air formed on one side of the substrate opposite to both sides of the magnetoelectric conversion element in a direction perpendicular to the opposing direction of the first and second magnetic body portions. And a second low magnetic permeability part.   The magnetic sensor according to claim 1, wherein a third low magnetic permeability portion having a lower magnetic permeability than air is provided on the surfaces of the first and second magnetic body portions. A flat substrate;
A magnetoelectric transducer formed on one surface of the substrate;
A support portion formed so as to form a recess in the thickness direction on the facing surface facing the one surface of the substrate;
A fourth low-permeability portion formed on the surface of the peripheral wall portion in the recess and having a lower magnetic permeability than air;
A fifth low magnetic permeability portion having a lower magnetic permeability than air formed on the opposing surface of the substrate connected to the fourth low magnetic permeability portion;
A third magnetic body portion formed to cover the fourth and fifth low magnetic permeability portions and a bottom portion of the recess;
With
The magnetic sensor, wherein the magnetoelectric conversion element is provided at a position facing the bottom.   The sixth low magnetic permeability portion having a magnetic permeability lower than that of air is formed in a region excluding the region where the magnetoelectric conversion element is formed on one surface of the substrate. The magnetic sensor described.   The magnetic sensor according to claim 4, wherein a fourth magnetic body portion is formed so as to cover the surface of the sixth low magnetic permeability portion and the surface of the magnetoelectric conversion element.   6. The magnetic sensor according to claim 3, wherein a magnetic permeability of a region excluding a region sandwiched between a bottom portion of the concave portion and the magnetoelectric conversion element in the substrate is lower than that of air. A flat substrate;
A first magnetic sensor formed on one side of the substrate;
A second magnetic sensor formed in the thickness direction of the substrate;
With
The magnetic sensor according to claim 1, wherein the first magnetic sensor is a magnetic sensor according to claim 1, and the second magnetic sensor is a magnetic sensor according to claim 3.   The magnetic sensor according to claim 1, wherein the low magnetic permeability portion is made of polyimide.

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