Magnetic sensor and method of manufacturing the same

Abstract

The magnetic sensor of the present application controls the size of the gap between the element formation surface and the magnetic concentrator based on the surface properties of the magnetic concentrator in a manner that converges the variation among products within a certain range. The sensor chip (20) is mounted in a manner that the element formation surface (20a) is perpendicular to the substrate (2), and the magnetic concentrator (30) is mounted in a manner that the surface (31) is opposite to the substrate (2) and the surface (32) is opposite to the element formation surface (20a). In the magnetic concentrator (30), the arithmetic mean waviness Wa of the surface (32) is 0.1 μm or less. In this way, if the arithmetic mean waviness Wa of the surface (32) of the magnetic concentrator (30) opposite to the element formation surface (20a) is planarized to 0.1 μm or less, the decrease in the detection sensitivity caused by the gap between the element formation surface (20a) and the magnetic concentrator (30) can be greatly reduced, and the variation in the detection sensitivity among products can be greatly suppressed.

Description

Technical Field

[0001] This invention relates to magnetic sensors and methods for manufacturing the same, and particularly to magnetic sensors comprising a sensor chip mounted on the surface of a substrate and a magnetizer, and methods for manufacturing the same. Background Technology

[0002] Magnetic sensors are widely used in ammeters and magnetic encoders. To improve detection sensitivity, a magnet collector is sometimes included in the magnetic sensor to concentrate magnetic flux onto the sensor chip. For example, Patent Document 1 discloses a magnetic sensor comprising a sensor chip mounted on a substrate with its element forming surface perpendicular to the substrate, and a magnet collector mounted on the substrate with its end facing the element forming surface.

[0003] The magnetic sensor described in Patent Document 1 has the advantage that, even when a long magnet is used, the magnet can be stably held on the substrate because the sensor chip is laid down at 90° and mounted on the substrate with the element forming surface perpendicular to the substrate.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-090192 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, when the machining precision of the magnet is low, the element forming surface of the sensor chip and the magnet cannot be completely fitted together, sometimes resulting in a tiny gap between them. Because this gap has a significant impact on the detection sensitivity of the magnetic field, it is desirable to minimize it and to control the size of the gap so that the deviation between products converges within a certain range.

[0009] In order to control the size of the gap by minimizing the gap between the sensor chip's component forming surface and the magnet, and by converging the deviations between products within a certain range, the following method can be adopted: improve the flatness of each surface by grinding or polishing the surface of the magnet, and make the angle formed by the two surfaces closer to 90°.

[0010] However, the relationship between the surface properties of the magnet and the gap generated between the component forming surface and the magnet is currently unclear, making it difficult to suppress deviations between products.

[0011] Therefore, the object of the present invention is to provide a magnetic sensor and a method thereof that can control the size of the gap between the element forming surface and the magnet based on the surface properties of the magnet in a way that brings the deviation between products within a certain range.

[0012] Technical solutions for solving the problem

[0013] The present invention provides a magnetic sensor, characterized in that it comprises: a substrate; a sensor chip having an element forming surface on which a magnetic sensitive element is formed, mounted on the surface of the substrate in such a way that the element forming surface is perpendicular to the surface of the substrate; and a magnet being mounted on the surface of the substrate with a first surface facing the surface of the substrate and a second surface facing the element forming surface of the sensor chip, wherein the arithmetic mean waviness Wa of the second surface is 0.1 μm or less.

[0014] According to the present invention, since the arithmetic mean waviness Wa of the second surface of the magnet opposite to the element forming surface is flattened to less than 0.1 μm, the decrease in detection sensitivity caused by the gap between the element forming surface and the magnet can be significantly reduced, and the deviation in detection sensitivity between products can be significantly suppressed.

[0015] In this invention, the flatness of the first and second surfaces of the magnet is also higher than that of at least one other surface. Accordingly, since the flatness of at least one other surface of the magnet is not improved, unnecessary manufacturing costs for processing that surface are not incurred. Thus, the increase in manufacturing costs can be suppressed.

[0016] In this invention, the magnet collector may also have a third surface, and the sensor chip and the magnet collector are fixed together by an adhesive coated on the third surface of the sensor chip and the magnet collector. The flatness of the first and second surfaces is higher than that of the third surface. Accordingly, unnecessary manufacturing costs for processing the third surface are avoided. Moreover, because the third surface has low flatness, the adhesive strength can be sufficiently ensured.

[0017] In this invention, the magnet collector may also have a fourth surface. The substrate and the magnet collector are fixed together by an adhesive coated on the surface of the substrate and the fourth surface of the magnet collector. The flatness of the first and second surfaces is higher than that of the fourth surface. Accordingly, unnecessary manufacturing costs for processing the fourth surface are avoided. Moreover, because the fourth surface has low flatness, the adhesive strength of the adhesive can be sufficiently ensured.

[0018] In this invention, the magnet may also be made of ferrite material. Although ferrite material has low flatness when it has been cut, the flatness of the first and second surfaces can be selectively improved by grinding or polishing.

[0019] The present invention provides a method for manufacturing a magnetic sensor, characterized by comprising: a first step of cutting a magnetizing body from a block made of magnetic material; a second step of grinding or polishing the magnetizing body having a first and a second surface to set the arithmetic mean waviness Wa of the second surface to 0.1 μm or less; a third step of mounting a sensor chip on the surface of a substrate in such a way that the element forming surface on which the magnetic sensing element is formed is perpendicular to the surface of the substrate; and a fourth step of mounting the magnetizing body on the surface of the substrate in such a way that the first surface is opposite to the surface of the substrate and the second surface is opposite to the element forming surface of the sensor chip.

[0020] According to the present invention, since the arithmetic mean waviness Wa of the second surface of the magnet opposite to the element forming surface is flattened to 0.1 μm or less, the decrease in detection sensitivity caused by the gap between the element forming surface and the magnet can be significantly reduced, and the deviation in detection sensitivity between products can be significantly suppressed.

[0021] In the second process, the flatness of the first and second surfaces of the magnet can be selectively improved by grinding or polishing. In this way, if the first and second surfaces of the magnet are selectively ground or polished, the flatness of the first and second surfaces is improved, and on the other hand, the increase in manufacturing costs associated with grinding or polishing can be minimized.

[0022] In this invention, the fourth step can also be performed while applying force to the magnet in a manner that the second surface of the magnet is pressed against the element forming surface of the sensor chip. This allows for a further reduction in the gap between the element forming surface of the sensor chip and the magnet.

[0023] In this invention, the magnet has a third surface. In the second step, the first and second surfaces are ground or polished instead of the third surface. In the fourth step, an adhesive is applied to the third surface of the sensor chip and the magnet. This avoids unnecessary manufacturing costs associated with processing the third surface. Furthermore, because the third surface has low flatness, the adhesive strength can be sufficiently ensured.

[0024] In this invention, the magnet may also have a fourth surface. In the second step, the first and second surfaces are ground or polished instead of the fourth surface. In the fourth step, an adhesive is applied to the surface of the substrate and the fourth surface of the magnet. This avoids unnecessary manufacturing costs associated with processing the fourth surface. Furthermore, because the fourth surface has low flatness, the adhesive strength can be sufficiently ensured.

[0025] Invention Effects

[0026] Thus, according to the present invention, the size of the gap between the element forming surface and the magnet can be controlled based on the surface properties of the magnet, in a way that the deviation between products is brought within a certain range. Attached Figure Description

[0027] Figure 1 This is a schematic perspective view showing the appearance of the magnetic sensor 10 according to a preferred embodiment of the present invention.

[0028] Figure 2 This is a schematic perspective view illustrating the structure of the element forming surface 20a of the sensor chip 20.

[0029] Figure 3 This is a circuit diagram used to illustrate the connection relationship of magnetic sensitive elements R1 to R4.

[0030] Figure 4 This is a general three-dimensional diagram used to illustrate the structure of the magnet 30.

[0031] Figure 5 (a) to (c) are schematic diagrams illustrating the application positions of adhesives 71 to 73.

[0032] Figure 6 It is a graph showing the relationship between the arithmetic mean waviness Wa of the surface 32 of the magnet 30 and the gap G generated between the element forming surface 20a and the magnet 30.

[0033] Figure 7 This is a graph showing the relationship between the gap G and the sensitivity of the magnetic sensor 10.

[0034] Figure 8 This is a flowchart illustrating the manufacturing process of the magnetic sensor 10.

[0035] Figure 9 This is a schematic diagram illustrating a method of supplying and curing adhesive 71 while applying force to the magnet 30. Detailed Implementation

[0036] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0037] Figure 1 This is a schematic perspective view showing the appearance of the magnetic sensor 10 according to a preferred embodiment of the present invention.

[0038] like Figure 1As shown, the magnetic sensor 10 of this embodiment includes a substrate 2 whose surface forms an xz plane, a sensor chip 20 and magnet collectors 30, 41, and 42 mounted on the surface of the substrate 2. The sensor chip 20 has an element forming surface 20a forming an xy plane, which is opposite to one end of the magnet collector 30 in the z direction. The magnet collectors 41 and 42 are disposed on the back side of the sensor chip 20. The magnet collectors 30, 41, and 42 are blocks made of soft magnetic materials with high permeability, such as ferrite.

[0039] like Figure 1 As shown, in this embodiment, the sensor chip 20 is mounted such that the element forming surface 20a of the sensor chip 20 is perpendicular to the surface of the substrate 2. That is, the sensor chip 20 is mounted in a state where it is tilted at 90° relative to the substrate 2. Therefore, even if the length of the magnet 30 in the z-direction is long, the magnet 30 can be stably fixed to the substrate 2.

[0040] Figure 2 This is a schematic perspective view illustrating the structure of the element forming surface 20a of the sensor chip 20.

[0041] like Figure 2 As shown, the sensor chip 20 has a generally cuboid shape, and four magnetic sensing elements R1 to R4 are formed on the element forming surface 20a constituting the xy plane. There are no particular limitations on the magnetic sensing elements R1 to R4, as long as their characteristics change according to the orientation or intensity of the magnetic field; for example, magnetoresistive elements can be used. In the following description, we will take the case where magnetic sensing elements R1 to R4 are magnetoresistive elements and have the same fixed magnetization direction as each other as an example. Here, magnetic sensing elements R1 and R3 are positioned in the same x-direction, and magnetic sensing elements R2 and R4 are positioned in the same x-direction. Furthermore, magnetic sensing elements R1 and R4 are positioned in the same y-direction, and magnetic sensing elements R2 and R3 are positioned in the same y-direction.

[0042] Magnetic layers 21 to 23 are formed on the element forming surface 20a of the sensor chip 20. Viewed from above, magnetic layer 21 is located approximately at the center of the element forming surface 20a, with magnetic layers 22 and 23 arranged on either side of it in the x-direction. While not particularly limited, magnetic layers 21 to 23 can be films made of composite magnetic materials containing magnetic fillers dispersed in resin materials, thin films or foils made of soft magnetic materials such as nickel or permalloy, or thin films or bulk sheets made of ferrites. Furthermore, magnetic sensitive elements R1 and R3 are disposed in the gap formed by magnetic layers 21 and 22, and magnetic sensitive elements R2 and R4 are disposed in the gap formed by magnetic layers 21 and 23.

[0043] Viewed from above, i.e., from the z-direction, the magnet collector 30 is disposed between magnetic sensitive elements R1, R3 and magnetic sensitive elements R2, R4, and has a cuboid shape with the z-direction as its longer side. The magnet collector 30 functions to concentrate the magnetic flux in the z-direction and separate the magnetic flux on both sides in the x-direction on the element forming surface 20a. The height of the magnet collector 30 in the z-direction is not particularly limited, but by further increasing the height in the z-direction, the selectivity of the magnetic flux in the z-direction can be improved. In this embodiment, the width of the magnet collector 30 in the y-direction is approximately the same as the width of the sensor chip 20 in the y-direction, but the present invention is not limited thereto.

[0044] One side and half of the back surface of the sensor chip 20 are covered by a magnet collector 41. Similarly, the other side and the remaining half of the back surface of the sensor chip 20 are covered by a magnet collector 42. While magnet collectors 41 and 42 are not strictly necessary in this invention, their presence can further improve the selectivity of the magnetic flux relative to the z-direction. Magnet collectors 41 and 42 each have overhang portions OH1 and OH2 that extend in the z-direction beyond the element forming surface 20a and are further bent towards the element forming surface 20a from this extended portion.

[0045] With the above structure, viewed from the z-direction, magnetic sensing elements R1 and R3 are located between the protruding portion OH1 of magnet collector 30 and magnet collector 41, while magnetic sensing elements R2 and R4 are located between the protruding portion OH2 of magnet collector 30 and magnet collector 42. Therefore, the magnetic flux concentrated by magnet collector 30, after being distributed approximately equally on both sides of the x-direction, is attracted by magnet collectors 41 and 42 via the protruding portions OH1 and OH2. At this time, because a portion of the magnetic flux passes through magnetic sensing elements R1 to R4, magnetic flux in opposite directions is imparted to magnetic sensing elements R1 and R3 and magnetic sensing elements R2 and R4.

[0046] Figure 3 This is a circuit diagram used to illustrate the connection relationship of magnetic sensitive elements R1 to R4.

[0047] like Figure 3As shown, magnetic sensitive element R1 is connected to terminal electrodes 53 and 56, magnetic sensitive element R2 is connected to terminal electrodes 54 and 55, magnetic sensitive element R3 is connected to terminal electrodes 53 and 54, and magnetic sensitive element R4 is connected to terminal electrodes 55 and 56. Here, a power supply potential Vcc is applied to terminal electrode 56, and a ground potential GND is applied to terminal electrode 54. Furthermore, magnetic sensitive elements R1 to R4 have identical magnetization directions, creating a difference between the resistance change of magnetic sensitive elements R1 and R3 on one side as observed from the magnet collector 30 and the resistance change of magnetic sensitive elements R2 and R4 on the other side as observed from the magnet collector 30. Thus, magnetic sensitive elements R1 to R4 form a differential bridge circuit, resulting in resistance changes of magnetic sensitive elements R1 to R4 corresponding to the magnetic flux density at terminal electrodes 53 and 55.

[0048] The differential signals output from terminal electrodes 53 and 55 are input to the substrate 2 or to a differential amplifier 61 disposed outside the substrate 2. The output signal of the differential amplifier 61 is fed back to terminal electrode 52. Figure 3 As shown, a compensation coil C is connected between terminal electrodes 51 and 52, thereby generating a magnetic field corresponding to the output signal of the differential amplifier 61. The compensation coil C can be integrated into the sensor chip 20. With the above structure, when a change in the resistance of the magnetic sensing elements R1 to R4 corresponding to the magnetic flux density occurs at terminal electrodes 53 and 55, a current corresponding to the magnetic flux density flows to the compensation coil C, generating a magnetic flux in the opposite direction. This cancels out the external magnetic flux. Furthermore, if the current output from the differential amplifier 61 is converted from current to voltage using the detection circuit 62, the intensity of the external magnetic flux can be detected.

[0049] Figure 4 This is a general three-dimensional diagram used to illustrate the structure of the magnet 30.

[0050] like Figure 4 As shown, the magnet collector 30 is a generally cuboid with six surfaces 31 to 36. Surface 31 forms the xz plane and is opposite to the surface of the substrate 2 when mounted. Surface 32 forms the xy plane and is opposite to the element forming surface 20a of the sensor chip 20 when mounted. Surface 33 is the xz plane located on the opposite side of surface 31. Surface 34 is the xy plane located on the opposite side of surface 32. Surfaces 35 and 36 are yz planes located on opposite sides of each other.

[0051] Furthermore, in this embodiment, the flatness of surfaces 31 and 32 of the magnet collector 30 is higher than that of the other surfaces 33 to 36. This is the result of selectively grinding or polishing surfaces 31 and 32 of the magnet collector 30, as will be described later. By grinding or polishing surfaces 31 and 32 of the magnet collector 30, not only is the flatness of surfaces 31 and 32 improved, but the angle formed by surfaces 31 and 32 is also made closer to 90°. As a result, when the magnet collector 30 is mounted on the substrate 2, because surface 31 is in close contact with the surface of the substrate 2 with virtually no gap, and surface 32 is in close contact with the element forming surface 20a of the sensor chip 20 with virtually no gap, the decrease in detection sensitivity caused by the gap between the element forming surface 20a and the magnet collector 30 can be suppressed, and the deviation in detection sensitivity between products can be reduced.

[0052] In particular, the surface 32 opposite to the element forming surface 20a is planarized such that the arithmetic mean waviness Wa (as defined in JIS B0601:2013) is less than 0.1 μm. If the arithmetic mean waviness Wa of surface 32 is less than 0.1 μm, the decrease in detection sensitivity caused by the gap between the element forming surface 20a and the magnet collector 30 can be significantly reduced, and the deviation in detection sensitivity between products can be significantly suppressed. Furthermore, if the surface 31 of the magnet collector 30 is planarized, the friction between the surface 31 of the magnet collector 30 and the substrate 2 is reduced, making it easier to slide the magnet collector 30 on the substrate 2 and abut against the sensor chip 20 during assembly. The arithmetic mean waviness Wa of surface 31 can be the same as or greater than that of surface 32.

[0053] like Figure 5 As shown, the magnet 30 can be fixed using adhesives 71-73. Figure 5 In the example shown in (a), adhesive 71 is applied to the surface 33 of the magnet collector 30 and the upper surface (xz plane) 20b of the sensor chip 20, thereby fixing the relative positional relationship between the sensor chip 20 and the magnet collector 30. Preferably, the surface 33 of the magnet collector 30 is rougher than surfaces 31 and 32. Accordingly, compared with the case where the surface 33 of the magnet collector 30 has the same flatness as surfaces 31 and 32, the adhesive strength of adhesive 71 can be improved. In addition, when adhesive 71 penetrates between the surface 32 of the magnet collector 30 and the element forming surface 20a, the gap between the two may widen, but in this embodiment, because the flatness of the surface 32 of the magnet collector 30 is improved, the penetration of adhesive 71 due to surface tension is less likely to occur.

[0054] In addition, Figure 5In the example shown in (b), adhesive 72 is applied to both the surface 34 of the magnet collector 30 and the surface of the substrate 2, thereby fixing the relative positional relationship between the substrate 2 and the magnet collector 30. Preferably, the surface 34 of the magnet collector 30 is rougher than surfaces 31 and 32. Accordingly, compared to the case where the surface 34 of the magnet collector 30 has the same flatness as surfaces 31 and 32, the adhesive strength of the adhesive 72 can be improved.

[0055] In addition, Figure 5 In the example shown in (c), adhesive 73 is applied to the surfaces 35 and 36 of the magnet collector 30 and the surface of the substrate 2, thereby fixing the relative positional relationship between the substrate 2 and the magnet collector 30. Preferably, the surfaces 35 and 36 of the magnet collector 30 are rougher than the surfaces 31 and 32. Accordingly, compared with the case where the surfaces 35 and 36 of the magnet collector 30 have the same flatness as the surfaces 31 and 32, the adhesive strength of the adhesive 73 can be improved.

[0056] However, in this invention, it is not necessary to use all of the adhesives 71 to 73; some adhesives, such as adhesive 73, may be omitted.

[0057] Figure 6 It is a graph showing the relationship between the arithmetic mean waviness Wa of the surface 32 of the magnet 30 and the gap G generated between the element forming surface 20a and the magnet 30.

[0058] like Figure 6 As shown, in multiple samples with an arithmetic mean waviness Wa of surface 32 of 0.5 μm, the measured values ​​of gap G deviate significantly between approximately 20 μm and approximately 100 μm. The value of gap G and its deviation decrease as the arithmetic mean waviness Wa of surface 32 decreases. In multiple samples with Wa of 0.3 μm, the measured values ​​of gap G are approximately 10 μm to approximately 40 μm (deviation of approximately 30 μm); in multiple samples with Wa of 0.2 μm, the measured values ​​of gap G are approximately 0 μm to approximately 30 μm (deviation of approximately 30 μm); and in multiple samples with Wa of 0.1 μm, the measured values ​​of gap G are approximately 0 μm to approximately 10 μm (deviation of approximately 10 μm). Thus, if Wa is 0.1 μm, not only can the absolute value of gap G be reduced, but the deviation of gap G can also be significantly suppressed. The smaller the arithmetic mean waviness Wa of surface 32, the better its characteristics. However, depending on the material properties of the magnet 30 and the grinding method, it is practically difficult to reduce the arithmetic mean waviness Wa to below 0.01 μm. Taking this into account, the practical value of Wa is 0.01 μm or more and 0.1 μm or less, preferably 0.03 μm or more and 0.05 μm or less.

[0059] Figure 7 This is a graph showing the relationship between the gap G and the sensitivity of the magnetic sensor 10.

[0060] like Figure 7 As shown, although the sensitivity of the magnetic sensor 10 is not solely determined by the gap G, a clear trend towards increased sensitivity as the gap G narrows can be observed. That is, the smaller the arithmetic mean waviness Wa of the surface 32, the higher the sensitivity of the magnetic sensor 10. Furthermore, if the surface 32 is planarized so that the arithmetic mean waviness Wa is below 0.1 μm, high sensitivity can be obtained, and sensitivity deviations can be significantly suppressed.

[0061] Next, the manufacturing method of the magnetic sensor 10 of this embodiment will be described.

[0062] Figure 8 This is a flowchart illustrating the manufacturing process of the magnetic sensor 10 in this embodiment.

[0063] First, after cutting out the magnet collector 30 from a block made of magnetic materials such as ferrite (step S11), the surfaces 31 and 32 of the magnet collector 30 are ground or polished, thereby improving the flatness of the surfaces 31 and 32 (step S12). After cutting out the magnet collector 30, the flatness of each surface 31 to 36 is low, and the angle formed by the two surfaces is also inaccurate. However, if the surfaces 31 and 32 of the magnet collector 30 are ground or polished, the flatness of the surfaces 31 and 32 is improved, and the angle formed by the surfaces 31 and 32 is infinitely close to 90°. If the other surfaces 33 to 36 are ground or polished, unnecessary increases in manufacturing costs are prevented. However, it is also possible to grind or polish only a portion of the surfaces 33 to 36.

[0064] On the other hand, simultaneously with the processing of the magnet collector 30, the sensor chip 20 is mounted in a manner where the element forming surface 20a is perpendicular to the substrate 2 (step S21). Then, the processed magnet collector 30 is mounted on the surface of the substrate 2 (step S22). The magnet collector 30 is mounted such that surface 31 faces the surface of the substrate 2, and surface 32 faces the element forming surface 20a of the sensor chip 20. As described above, because the surfaces 31 and 32 of the magnet collector 30 have high flatness and the angle formed by the surfaces 31 and 32 is infinitely close to 90°, the surface 32 of the magnet collector 30 can be made to fit tightly against the element forming surface 20a of the sensor chip 20 with almost no gap.

[0065] Next, the magnet collector 30 is fixed by supplying and curing adhesives 71-73 (step S23). At this time, it is preferable to supply and cure the adhesive while applying force to the magnet collector 30 so that its surface 32 is properly pressed against the element forming surface 20a of the sensor chip 20. For example, as... Figure 9As shown, preferably after the magnet collector 30 is placed on the substrate 2, adhesive 71 is supplied from the dispenser 70 while applying force to the magnet collector 30 in the -z direction from the surface 34 side using the force-applying clamp 81. At this time, it is preferable to use the fixing clamp 82 to support the back side of the sensor chip 20 so that the sensor chip 20 can move in the -z direction or not fall over. If adhesive 71 is supplied and cured using such clamps 81 and 82, the surface 32 of the magnet collector 30 can be properly pressed against the element forming surface 20a of the sensor chip 20, and the penetration of adhesive 71 into the space between the surface 32 of the magnet collector 30 and the element forming surface 20a of the sensor chip 20 can be prevented. Here, if the surface 31 of the magnet collector 30 is also planarized, the friction between the magnet collector 30 and the substrate 2 is reduced, making it easier to slide the magnet collector 30 on the substrate 2 and abut against the sensor chip 20.

[0066] The supply and curing of adhesives 72 and 73 can be carried out in the same way, as long as they are fixed in place by clamps 81 and 82.

[0067] As explained above, the magnetic sensor 10 of this embodiment selectively improves the flatness of the surfaces 31 and 32 of the magnet collector 30, enabling the surface 32 of the magnet collector 30 to adhere to the element forming surface 20a of the sensor chip 20 with virtually no gaps. Furthermore, the penetration of the adhesive 71 between the surface 32 of the magnet collector 30 and the element forming surface 20a of the sensor chip 20 is less likely. Moreover, since at least a portion of the other surfaces 33 to 36 are not ground or polished, the bonding strength of the adhesives 71 to 73 can be sufficiently ensured.

[0068] The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. Various modifications can be made without departing from the spirit of the present invention, and these modifications are also included within the scope of the present invention.

[0069] Explanation of reference numerals in the attached figures

[0070] 2 substrates

[0071] 10 magnetic sensors

[0072] 20 sensor chips

[0073] 20a Component Forming Surface

[0074] The upper surface of the 20b sensor chip

[0075] 21-23 magnetic layers

[0076] Magnets 30, 41, and 42

[0077] Surface of magnets 31-36

[0078] 51-56 terminal electrodes

[0079] 61 Differential Amplifier

[0080] 62 detection circuit

[0081] 70 Distributor

[0082] 71-73 Adhesive

[0083] 81 Force-applying clamp

[0084] 82 Fixture

[0085] C compensation coil

[0086] OH1, OH2 (highlighted parts)

[0087] R1~R4 magnetic sensitive elements

Claims

1. A magnetic sensor, characterized in that, have: substrate; A sensor chip having an element forming surface on which a magnetic sensitive element is formed, and mounted on the surface of the substrate in such a way that the element forming surface is perpendicular to the surface of the substrate; as well as A magnet is mounted on the surface of the substrate with its first surface facing the surface of the substrate and its second surface facing the element of the sensor chip. The magnet has a third surface located on the opposite side of the first surface. The sensor chip and the magnet collector are fixed together by an adhesive applied to the third surface of the sensor chip and the magnet collector. The flatness of the second surface is greater than that of the first surface. The flatness of the first surface is higher than that of the third surface. The arithmetic mean waviness Wa of the second surface is less than 0.1 μm.

2. The magnetic sensor according to claim 1, characterized in that, The magnet also has a fourth surface located on the opposite side of the second surface. The substrate and the magnet are fixed together by an adhesive applied to the surface of the substrate and the fourth surface of the magnet. The flatness of the first and second surfaces is higher than that of the fourth surface.

3. The magnetic sensor according to claim 2, characterized in that, The magnet also has a fifth and a sixth surface that are orthogonal to the first to fourth surfaces and located on opposite sides of each other. The substrate and the magnet are fixed together by an adhesive applied to the surface of the substrate and the fifth and sixth surfaces of the magnet. The flatness of the first and second surfaces is higher than that of the fifth and sixth surfaces.

4. The magnetic sensor according to any one of claims 1 to 3, characterized in that, The magnet is made of ferrite material.

5. A method for manufacturing a magnetic sensor, characterized in that, have: The first step is to cut out the magnet from a block made of magnetic material; In the second step, the first and second surfaces are ground or polished without grinding or polishing the third surface of the magnet having the first and second surfaces and the third surface located on the opposite side of the first surface, so that the flatness of the second surface is higher than that of the first surface, and the flatness of the first surface is higher than that of the third surface, and the arithmetic mean waviness Wa of the second surface is set to 0.1 μm or less. The third step involves mounting a sensor chip onto the surface of the substrate in such a way that the element forming surface with the magnetic sensitive element is perpendicular to the surface of the substrate. as well as In the fourth step, the magnet is mounted on the surface of the substrate with the first surface facing the surface of the substrate and the second surface facing the element of the sensor chip, and an adhesive is applied to the third surface of the sensor chip and the magnet.

6. The method for manufacturing a magnetic sensor according to claim 5, characterized in that, The fourth step is performed while applying force to the magnet in such a way that the second surface of the magnet is pressed against the element forming surface of the sensor chip.

7. The method for manufacturing a magnetic sensor according to claim 5, characterized in that, The magnet also has a fourth surface located on the opposite side of the second surface. In the second step, the first and second surfaces are not ground or polished, but the fourth surface is not ground or polished. In the fourth step, an adhesive is applied to the surface of the substrate and the fourth surface of the magnet.

8. The method for manufacturing a magnetic sensor according to claim 7, characterized in that, The magnet also has a fifth and a sixth surface that are orthogonal to the first to fourth surfaces and located on opposite sides of each other. In the second step, the first and second surfaces are not ground or polished, but the fifth and sixth surfaces are ground or polished. In the fourth step, an adhesive is applied to the surface of the substrate and the fifth and sixth surfaces of the magnet.

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