JP2016017830A - Magnetic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic sensor with which it is possible to generate a high magnetic field allowing for sensitivity adjustment and adjust sensitivity with high accuracy without incurring an increase in chip area, etc.SOLUTION: The magnetic sensor comprises: hall elements 3a, 3b formed in a semiconductor substrate 2; a magnetic convergence plate 4 provided on the semiconductor substrate 2; and internal coils 5a, 5b disposed above each of the hall elements 3a, 3b, the magnetic convergence plate 4 having projections 4a, 4b projecting to the semiconductor substrate 2 side in its end area, with the hall elements 3a, 3b disposed at positions where they overlap the projections 4a, 4b of the magnetic convergence plate 4 in the top plan view, and the internal coils 5a, 5b being disposed so as to enclose the projections 4a, 4b. As the projections 4a, 4b that are portions of the magnetic convergence plate 4 are disposed inside the internal coils 5a, 5b, the magnetic permeability inside the internal coils 5a, 5b is heightened and the generated magnetic field is augmented.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a magnetic sensor for detecting magnetism, and more particularly to a magnetic sensor capable of performing sensitivity adjustment.

Conventionally, as a magnetic sensor, a Hall element provided on a semiconductor substrate and a magnetic focusing plate having a magnetic focusing function provided on the Hall element are provided. 2. Description of the Related Art A magnetic sensor that detects an element is known.
FIG. 1 is an example of a configuration diagram for explaining a magnetic sensor in which magnetic converging is performed by a magnetic converging plate and the magnetic field strength is detected by a Hall element.
As shown in FIG. 1, the magnetic sensor 100 includes a semiconductor circuit 101, and the semiconductor circuit 101 includes a semiconductor substrate 103 and Hall elements 104 a and 104 b provided on the semiconductor substrate 103. In the magnetic sensor 100, a protective layer 105 and an adhesive layer 106 are sequentially provided on a semiconductor circuit 101, and a magnetic convergence plate 102 is provided on the adhesive layer 106.

As described above, for example, a sensor described in Patent Document 1 has been proposed for a magnetic sensor that combines a Hall element and a magnetic focusing plate having a magnetic focusing function. The sensor described in Patent Document 1 relates to a magnetic field direction detection sensor that can determine the direction of a magnetic field in two dimensions, and includes a magnetic converging plate having a flat shape, a first Hall element, and a second Hall element. Hall elements are arranged in the end region of the magnetic flux concentrating plate.
For example, as shown in FIG. 2 and FIG. 3, a magnetic sensor is proposed in which a horizontal magnetic field generating coil is provided in the magnetic sensing direction of the magnetic sensing unit to perform sensitivity measurement (see, for example, Patent Document 2). ).
FIG. 2 is a top view of a magnetic sensor that performs sensitivity measurement, and FIG. 3 is a schematic cross-sectional view schematically showing the cross-section thereof.

  The magnetic sensor 100a shown in FIGS. 2 and 3 is provided with a plurality of Hall elements 121a and 121b (X-axis Hall elements) and 121c and 121d (Y-axis Hall elements) on a semiconductor substrate (not shown) spaced apart from each other. A disk-shaped magnetic converging plate 122 having a magnetic converging function is provided on the semiconductor substrate so as to cover the Hall elements 121a to 121d. Below the central region of the magnetic flux concentrating plate 122, a horizontal magnetic field generating coil 123 is provided for sensitivity measurement for generating a horizontal magnetic field component in a direction perpendicular to the magnetic sensitive direction of the magnetic sensitive portions of the Hall elements 121a to 121d. It has been. A horizontal magnetic field component generated by the horizontal magnetic field generating coil 123 is configured to be detected by Hall elements 121 a to 121 d provided in the end region of the magnetic flux concentrating plate 122. The vertical magnetic field generating coils 124a to 124d are provided for sensitivity measurement for generating a vertical magnetic field component in a direction parallel to the magnetic sensitive direction of the magnetic sensitive portions of the Hall elements 121a to 121d.

JP 2002-071381 A International Publication No. 2008/123144 Pamphlet

However, in the conventional configuration, for example, in a test process for testing a magnetic sensor, a magnetic field generated by a sensitivity measurement coil is small, and sensitivity adjustment cannot be performed with high accuracy. In addition, in order to generate a high magnetic field, it is necessary to flow a large current, and there is a problem that the chip area increases accordingly. The same applies to applications other than the test process in which the sensitivity of the magnetic sensor element is adjusted while detecting a signal, and there is a problem that the sensitivity cannot be adjusted accurately or the current consumption increases.
The present invention has been made in view of such a problem. The object of the present invention is to generate a large magnetic field without increasing the chip area and to perform sensitivity adjustment with high accuracy. It is to provide a magnetic sensor.

A magnetic sensor according to one aspect of the present invention includes a magnetic sensor element (for example, Hall elements 3a and 3b shown in FIG. 5) formed on a semiconductor substrate, and a magnetic convergence plate (for example, FIG. 5) provided above the magnetic sensor element. 5) and a first built-in coil (for example, built-in coils 5a and 5b shown in FIG. 5) disposed between the magnetic sensor element and the magnetic focusing plate, The magnetic flux concentrating plate has a protruding portion (for example, protruding portions 4a and 4b shown in FIG. 5) protruding toward the magnetic sensor element side, and the first built-in coil is disposed so as to surround the protruding portion. It is characterized by.
The magnetic converging plate may have a disk shape, and the protrusion may be provided in an end region of the magnetic converging plate.
An interlayer insulating layer (for example, an interlayer insulating layer 6 shown in FIG. 5) is further provided between the semiconductor substrate and the magnetic flux concentrating plate, and the protruding portion and the first built-in coil are disposed in the interlayer insulating layer. It may be.

The magnetic converging plate includes a magnetic converging plate main body (for example, magnetic converging plate 10 shown in FIG. 9) and the protruding portion (for example, shown in FIG. 10b), the protrusion may be disposed between the magnetic focusing plate body and the magnetic sensor element, and the first built-in coil may be disposed so as to surround the protrusion.
A second built-in coil (for example, built-in coil 7 shown in FIG. 8) different from the first built-in coil may be provided on the magnetic sensor element side in the central region of the magnetic flux concentrating plate.
A coil current source for supplying a coil current to the first built-in coil or the second built-in coil may be further provided.

  A magnetic sensor according to another aspect of the present invention includes a magnetic sensor element (for example, Hall elements 3a and 3b shown in FIG. 5) formed on a semiconductor substrate, and a magnetic focusing plate (for example, provided above the magnetic sensor element). 5 and a magnetic focusing plate 4) and a sensitivity adjusting built-in coil (for example, built-in coils 5a and 5b shown in FIG. 5) disposed between the magnetic sensor element and the magnetic focusing plate. The magnetic converging plate has a protrusion (for example, protrusions 4a and 4b shown in FIG. 5) protruding toward the magnetic sensor element, and the protrusion is a magnetic field generated by the sensitivity adjustment built-in coil. It arrange | positions in the position which strengthens.

The magnetic sensor element may be a Hall element.
According to another aspect of the present invention, there is provided a method of manufacturing a magnetic sensor comprising: a step of forming a Hall element on a semiconductor substrate; and an interlayer insulation having a sensitivity adjustment coil using metal wiring on the semiconductor substrate on which the Hall element is formed. Forming a layer, removing the interlayer insulating layer in the inner region of the sensitivity adjusting coil to form a cavity, and forming a magnetic flux concentrator on the cavity and the interlayer insulating layer And.

  According to one embodiment of the present invention, a high magnetic field can be generated without increasing the chip area, and as a result, sensitivity adjustment of the magnetic sensor can be performed with high accuracy.

It is a block diagram which shows an example of the conventional magnetic sensor. It is a top view which shows an example of the magnetic sensor made to perform a sensitivity measurement. It is a cross-sectional schematic diagram which shows an example of the magnetic sensor made to perform a sensitivity measurement. It is a cross-sectional schematic diagram which shows an example of the magnetic sensor used as the premise of this invention. It is a cross-sectional schematic diagram which shows an example of the magnetic sensor in 1st Embodiment of this invention. It is a cross-sectional schematic diagram which shows an example of the magnetic sensor in 2nd Embodiment. It is a schematic diagram which shows the generation | occurrence | production state of the horizontal magnetic field component by the magnetic sensor in 2nd Embodiment. It is a schematic diagram which shows the generation | occurrence | production state of the perpendicular magnetic field component by the coil for perpendicular direction magnetic field generation of the magnetic sensor in 2nd Embodiment. It is a cross-sectional schematic diagram which shows an example of the magnetic sensor in 3rd Embodiment. It is a cross-sectional schematic diagram which shows an example of the magnetic sensor in the modification of this invention. It is process drawing which shows an example of the manufacturing method of the magnetic sensor in 1st Embodiment. It is process drawing which shows the other example of the manufacturing method of the magnetic sensor in this invention.

<Prerequisite configuration>
First, an example of a configuration of a magnetic sensor (hereinafter also referred to as a premise magnetic sensor) which is a premise of the present invention will be described.
FIG. 4 is a schematic cross-sectional view showing an example of the premise magnetic sensor 1. As shown in FIG. 4, the premise magnetic sensor 1 includes Hall elements 3a and 3b (magnetic sensor elements) formed on the semiconductor substrate 2, a magnetic focusing plate 4 provided on the semiconductor substrate 2, a Hall element 3a, Built-in coils 5a and 5b (first built-in coil, built-in coil for sensitivity adjustment) disposed above each of 3b. An interlayer insulating layer 6 is formed on the semiconductor substrate 2, and the magnetic flux concentrating plate 4 is disposed on the semiconductor substrate 2 via the interlayer insulating layer 6. The built-in coils 5 a and 5 b are formed in the interlayer insulating layer 6. The Hall elements 3a and 3b are arranged at positions overlapping the end region of the magnetic flux converging plate 4 when viewed from above. The magnetic converging plate is a soft magnetic material having a magnetic converging function.

When a coil current is supplied to the built-in coils 5a and 5b, a magnetic field is generated by the built-in coils 5a and 5b, and the Hall elements 3a and 3b detect the magnetic field as Hall electromotive force. By performing signal processing on the detected hall electromotive force, sensitivity adjustment and the like can be performed.
At this time, the magnetic field generated by the built-in coils 5a and 5b is approximated by the following formula (1).
B0 = μa × n × I / 2r (1)
Here, μa is the magnetic permeability of the interlayer insulating layer 6, n is the number of turns of the built-in coils 5a and 5b, I is the coil current supplied to the built-in coils 5a and 5b, and r is the radius of the built-in coils 5a and 5b. .
The direction in which the magnetic field is generated can be changed to the reverse direction by reversing the direction of the coil current flowing through the built-in coils 5a and 5b.

<First Embodiment>
Next, the first embodiment will be described.
FIG. 5 is a schematic cross-sectional view showing an example of the magnetic sensor 11 in the first embodiment.
The magnetic sensor 11 in the first embodiment is disposed above the Hall elements 3a and 3b formed on the semiconductor substrate 2, the magnetic convergence plate 4 provided on the semiconductor substrate 2, and the Hall elements 3a and 3b, respectively. It is a magnetic sensor provided with built-in coils 5a and 5b.
The magnetic converging plate 4 has projecting portions 4 a and 4 b projecting downward, that is, toward the semiconductor substrate 2, in an end region in a cross-sectional view. The magnetic flux concentrating plate 4 is formed on the semiconductor substrate 2 via an interlayer insulating layer 6 formed on the semiconductor substrate 2, and the protrusions 4 a and 4 b are embedded in the interlayer insulating layer 6. .

In this case, the magnetic flux concentrating plate 4 is disposed on the interlayer insulating layer 6, but an adhesive layer may be further provided between the magnetic converging plate 4 and the interlayer insulating layer 6. In this case, the protruding portions 4a and 4b are formed separately from the main body portion of the magnetic converging plate 4 as in the magnetic converging plate main body 10 and the built-in magnetic converging plates 10M (10a and 10b) of FIG. May be.
The Hall elements 3a and 3b are arranged in positions overlapping the end regions of the magnetic flux converging plate 4 in the top view, that is, the protrusions 4a and 4b, and between the Hall elements 3a and 3b and the protrusions 4a and 4b. Interlayer insulating layer 6 is interposed.

  The built-in coils 5a and 5b are disposed in the interlayer insulating layer 6 and are disposed so as to surround the protrusions 4a and 4b, respectively. The built-in coils 5a and 5b are coils for generating a vertical magnetic field. By supplying a coil current to the built-in coils 5a to 5d, a vertical magnetic field component is generated between the magnetic flux converging plate 4 and the Hall elements 3a to 3d, and the Hall elements 3a to 3d detect this vertical magnetic field component. It is configured as follows.

The built-in coils 5a and 5b are preferably loop-shaped coils, and various shapes such as a circle, a square, and a rectangle can be selected depending on the shape, size, number, and the like of the hall elements 3a and 3b.
Compared with the configuration of the premise magnetic sensor 1 shown in FIG. 4, the magnetic sensor 11 has a part of the magnetic convergence plate 4, specifically, the protrusions 4 a and 4 b embedded in the interlayer insulating layer 6. The difference is that the built-in coils 5a and 5b are arranged so as to surround the protrusions 4a and 4b protruding below the converging plate 4, that is, toward the semiconductor substrate 2 side.

At this time, the magnetic field generated from the built-in coils 5a and 5b is approximated by the following equation (2).
B1 = μm × n × I / 2r (2)
Here, μm represents the magnetic permeability of the magnetic converging plate 4, n represents the number of coil turns of the built-in coils 5a and 5b, I represents the coil current, and r represents the radius.
Compared with the magnetic field of the above formula (1), the permeability is μa (the permeability of the interlayer insulating layer 6) in the formula (1), whereas in the formula (2), the permeability is μm (the permeability of the magnetic focusing plate 4). Magnetic susceptibility). Since the magnetic permeability of the magnetic flux concentrating plate 4 is higher than the magnetic permeability of the interlayer insulating layer 6, B0 <B1.

In 1st Embodiment, since it has the structure by which a part (projection part 4a, 4b) of the magnetic convergence board 4 which is a soft magnetic body is arrange | positioned in the built-in coils 5a and 5b, built-in coils 5a and 5b. The internal magnetic permeability is increased to increase the generated magnetic field. As a result, a large magnetic field corresponding to the increased amount is generated.
Therefore, even when the sensitivity adjustment test process is performed with as large a magnetic field as possible, or in applications where sensitivity adjustment is performed in a time-sharing manner using a built-in coil, a large magnetic field can be generated with a small coil current. As a result, the sensitivity of the magnetic sensor element can be adjusted with higher accuracy.

In addition, as described above, since the generated magnetic field can be increased without flowing a large current, it can be realized without increasing the chip area on which the magnetic sensor 11 is mounted.
Also, a smaller amount of current may be used to generate the same magnitude magnetic field. Therefore, it is possible to reduce the layout area of a coil current source (not shown) that supplies a coil current to the built-in coils 5a to 5d, switches, and the like. As for the coil current to the built-in coils 5a to 5d, a coil current source may be provided as a part of the components of the magnetic sensor 11, and the coil current may be supplied from this coil current source. The coil current may be supplied from a coil current source provided in the circuit.

In addition, as shown in FIG. 5, when the protrusions 4a and 4b are provided on the magnetic flux concentrating plate 4, even if the protrusions 4a and 4b are formed in the same shape, the Hall element 3a is caused by an error in the shape or the arrangement position. 3b may be affected. That is, by providing the protrusions 4a and 4b, the Hall elements 3a and 3b are affected, which may affect the detection accuracy of the magnetic sensor 11 itself. However, since the sensitivity of the Hall elements 3a and 3b is adjusted using a magnetic field generated by supplying a coil current to the built-in coils 5a and 5b, the Hall elements 3a and 3b that take into account the influence of the protrusions 4a and 4b are used. Sensitivity adjustment is performed using the detection signal. Therefore, even if the protrusions 4a and 4b that may affect the Hall elements 3a and 3b are provided, the magnetic sensor 11 is not affected at all by performing sensitivity adjustment. Thereby, sensitivity adjustment can be performed with high accuracy.
In the first embodiment, the case where the present invention is applied to a magnetic sensor that performs sensitivity adjustment in a two-dimensional magnetic field has been described. However, the present invention is not limited to this, and four lines are formed so that line segments that connect opposing Hall elements are orthogonal to each other. The present invention can also be applied to a magnetic sensor in which a Hall element is arranged and sensitivity adjustment in a three-dimensional magnetic field can be performed.

Second Embodiment
Next, a second embodiment will be described.
FIG. 6 is a schematic cross-sectional view showing an example of the magnetic sensor 21 in the second embodiment. A top view of the magnetic sensor 21 is shown in FIG.
The magnetic sensor 21 in the second embodiment is disposed above the Hall elements 3a to 3d formed on the semiconductor substrate 2, the magnetic convergence plate 4 provided on the semiconductor substrate 2, and the Hall elements 3a to 3d, respectively. The magnetic sensor 21 includes a built-in coil 7 (second built-in coil) different from the built-in coils 5a to 5d. The magnetic flux concentrating plate 4 has, for example, a disk shape, and has protrusions 4 a to 4 d that protrude downward, that is, toward the semiconductor substrate 2, in the end region in a cross-sectional view. The protrusions 4a to 4d are arranged at positions that are line-symmetric with respect to a line segment that connects the protrusions 4a and 4b.

Further, the magnetic flux concentrating plate 4 is disposed on the semiconductor substrate 2 via an interlayer insulating layer 6 formed on the semiconductor substrate 2, and the protruding portions 4 a to 4 d are embedded in the interlayer insulating layer 6. Yes. In this case, the magnetic flux concentrating plate 4 is disposed on the interlayer insulating layer 6, but an adhesive layer may be further provided between the magnetic converging plate 4 and the interlayer insulating layer 6.
As shown in FIG. 6, corresponding Hall elements 3 a to 3 d are arranged at positions overlapping the protrusions 4 a to 4 d in the end region of the magnetic flux converging plate 4 in a top view, and the Hall elements 3 a to 3 d and the protrusions are arranged. Interlayer insulating layer 6 is interposed between 4a-4d. The Hall elements 3a and 3b operate as, for example, Hall elements that detect a magnetic field in the X-axis direction, and the Hall elements 3c and 3d operate as Hall elements that detect a magnetic field in the Y-axis direction orthogonal to the X-axis.

The built-in coils 5a to 5d are arranged so as to surround the corresponding protrusions 4a to 4d, respectively. The built-in coil 7 is disposed below the central region of the magnetic flux converging plate 4 in a top view and is disposed at a vertical position equivalent to the built-in coils 5a to 5d. That is, the built-in coils 5 a to 5 d and the built-in coil 7 are arranged in the interlayer insulating layer 6.
That is, the magnetic sensor 21 in the second embodiment detects the magnetic sensitivities in the horizontal direction (X, Y) and the vertical direction (Z) orthogonal to each other using the detection signals of the Hall elements 3a to 3d. In addition, since a part of the magnetic flux converging plate 4, that is, the protruding portions 4a to 4d are arranged in the built-in coils 5a to 5d, the built-in coils are similar to the magnetic sensor 11 in the first embodiment. The coils 5a to 5d are configured to increase the magnetic permeability inside the coils and enhance the generated magnetic field.

Next, detection of the horizontal magnetic field component and the vertical magnetic field component using the built-in coils 5a to 5d and the built-in coil 7 will be described with reference to FIGS.
7 and 8, (a) is a top view of the magnetic sensor 21, and (b) is a schematic cross-sectional view of the magnetic sensor 21.
In the detection of the horizontal magnetic field component, as shown in FIG. 7B, a coil current is supplied to the built-in coil 7 as a horizontal magnetic field generating coil. A vertical magnetic field component having a correlation with the component is generated, and the generated vertical magnetic field component is detected by the Hall elements 3a to 3d.

  Further, the Hall elements 3 a to 3 d and the built-in coil 7 are arranged on the same side with respect to the magnetic convergence plate 4. As shown in FIG. 7A, the built-in coil 7 is preferably a planar spiral coil, but the outer shape may be various shapes such as a circle, an octagon, and a rectangle. The size and the number of turns of the built-in coil 7 can be variously selected depending on the efficiency of the generated magnetic field, the diameter of the magnetic converging plate, the arrangement of the Hall elements 3a to 3d, and the like.

The built-in coil 7 can be formed using a metal wiring layer by a normal IC process. In this case, whether to use a layer close to a metal substrate, a far layer, or a plurality of wiring layers can be selected in consideration of the required magnetic field generation amount and coil efficiency.
As shown in FIG. 8, the built-in coils 5a to 5d as the vertical magnetic field generating coils are coils that generate a vertical magnetic field component in a direction parallel to the magnetic sensing direction of the magnetic sensing portions of the Hall elements 3a to 3d. A vertical magnetic field component generated by supplying a coil current to the built-in coils 5a to 5d is detected by the Hall elements 3a to 3d provided in the end region of the magnetic convergence plate 4.

Accordingly, the Hall elements 3a to 3d detect the horizontal magnetic field component generated by the built-in coil (horizontal magnetic field generating coil) 7 and the vertical magnetic field component generated by the built-in coils (vertical magnetic field generating coils) 5a to 5d. Combines detection.
In FIG. 6, the built-in coils 5 a to 5 d have been described in the case where they are arranged at the same vertical position as the built-in coil 7, but the present invention is not limited to this. The built-in coils 5a to 5d may be arranged at different vertical positions from the built-in coil 7. For example, the built-in coils 5a to 5d may be arranged directly below the hall elements 3a to 3d.

The built-in coils 5a to 5d are desirably loop-shaped coils, and various shapes such as a circle, a square, and a rectangle can be selected depending on the shape, size, number, and the like of the Hall elements 3a to 3d.
The built-in coils 5a to 5d can be formed using a metal wiring layer by a normal IC process. In this case, whether to use a layer close to a metal substrate, a far layer, or a plurality of wiring layers can be selected in consideration of the required magnetic field generation amount and coil efficiency.

Returning to FIG. 7, the generation state of the horizontal magnetic field component by the built-in coil 7 as the horizontal direction magnetic field generating coil of the magnetic sensor 21 according to the present invention is schematically shown in FIG. 7.
When the built-in coil 7 is energized, as indicated by arrows in FIG. 7B, horizontal magnetic field components (X-axis component, Y-axis component) in the direction perpendicular to the magnetic sensing direction of the magnetic sensing portions of the Hall elements 3a to 3d. And a vertical magnetic field component (Z-axis component) is generated between the magnetic flux converging plate 4 and the Hall elements 3a to 3d.

Since this vertical magnetic field component has a correlation with the horizontal magnetic field component, a horizontal magnetic field generated in a direction perpendicular to the magnetic sensing direction of the magnetic sensing unit by detecting this vertical magnetic field component with the Hall elements 3a to 3d. The intensity of the component can be detected.
That is, the Hall elements 3a to 3d can detect a horizontal magnetic field component generated by the built-in coil 7 in a direction perpendicular to the magnetic sensing direction of the magnetic sensing parts of the Hall elements 3a to 3d.

FIG. 8A and FIG. 8B schematically show the state of vertical magnetic field components generated by the built-in coils 5a to 5d of the magnetic sensor 21 according to the present invention.
When the built-in coils 5a to 5d are energized, a vertical magnetic field component (Z-axis component) is generated between the magnetic flux converging plate 4 and the Hall elements 3a to 3d, as indicated by arrows in FIG. 8B.
By detecting this vertical magnetic field component with the Hall elements 3a to 3d, the intensity of the vertical magnetic field component can be detected. That is, the Hall elements 3a to 3d can detect a vertical magnetic field component generated by the built-in coils 5a to 5d and between the magnetic flux converging plate 4 and the Hall elements 3a to 3d.

The horizontal magnetic field component generated by the built-in coil 7 depends on the thickness of the magnetic focusing plate 4 of the magnetic sensor 21 and the distance between the magnetic focusing plate 4 and the Hall elements 3a to 3d. The vertical magnetic field component generated by the Hall elements 3a to 3d depends on the distance between the magnetic flux converging plate 4 and the Hall elements 3a to 3d.
In the magnetic sensor 21 having such a configuration, the built-in coil 7 and / or the built-in coils 5a to 5d are energized to generate a magnetic field. The generated magnetic field passes through the magnetic sensitive surfaces of the Hall elements 3a to 3d via the magnetic converging plate 4, and the magnetic field is detected. Then, the detection signals of the hall elements 3a to 3d are fetched in a time division manner, and based on these, the signals are decomposed into X, Y, and Z axis components, and sensitivity adjustment is performed based on this. In addition, as a method of decomposing | disassembling into X, Y, and Z-axis component, it can decompose | disassemble by well-known procedures, such as the procedure described in the international publication 2008/123144 pamphlet, for example.

Also in the second embodiment, since the magnetic permeability inside the coils of the built-in coils 5a to 5d can be increased and the generated magnetic field can be enhanced, it is possible to obtain the same operational effects as the first embodiment, that is, Thus, it is possible to realize the magnetic sensor 21 that can adjust the sensitivity of the three axes with higher accuracy.
7 and 8, a coil current source 50 is a current source for supplying coil current to the built-in coils 5 a to 5 d and the built-in coil 7. A dedicated current source for supplying a coil current to each of the built-in coils 5a to 5d and the built-in coil 7 may be individually provided. Further, the coil current source 50 may be provided as a part of a component of the magnetic sensor 21, or a coil current may be supplied from a coil current source 50 provided outside the magnetic sensor 21.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
FIG. 9 is a schematic cross-sectional view of the magnetic sensor 31 of the third embodiment.
The magnetic sensor 31 of the third embodiment is the same as the magnetic sensor 21 of the second embodiment except that the shape of the magnetic flux concentrating plate 4 is different.

  That is, the magnetic sensor 31 according to the third embodiment includes a magnetic focusing plate body 10 formed on the interlayer insulating layer 6 as a magnetic focusing plate and a built-in magnetic focusing plate formed separately from the magnetic focusing plate body 10. A board. This built-in magnetic converging plate is provided corresponding to each of the Hall elements 3a to 3d. As shown in FIG. 9, the built-in magnetic converging plates 10a and 10b corresponding to the Hall elements 3a and 3b are shown in FIG. A built-in magnetic focusing plate corresponding to the Hall element 3c that is not provided and a built-in magnetic focusing plate corresponding to the Hall element 3d are provided. These built-in magnetic converging plates are similar to the Hall elements 3a to 3d in that a line segment connecting the built-in magnetic converging plates 10a and 10b corresponding to the Hall elements 3a and 3b and two built-in magnetic elements corresponding to the Hall elements 3c and 3d. It arrange | positions so that the line segment which connects a convergence board may orthogonally cross. Here, four built-in magnetic focusing plates corresponding to the Hall elements 3a to 3d are described as built-in magnetic focusing plates 10M.

  The built-in magnetic converging plate 10M has a disk-shaped magnetic converging plate main body as viewed from above, with the interlayer insulating layer 6 interposed between the corresponding Hall elements 3a to 3d and the magnetic converging plate main body 10, respectively. 10 end regions and the built-in magnetic flux concentrating plates 10M overlap each other, and the hall elements 3a to 3d and the corresponding built-in magnetic converging plates 10M overlap. That is, in the magnetic sensor 21 according to the second embodiment, the protrusions 4a to 4d and the main body portion of the magnetic flux concentrating plate 4 (the magnetic converging plate portion formed on the interlayer insulating layer 6) are formed as separate bodies. Yes.

The built-in coils 5a to 5d are arranged so as to surround the corresponding built-in magnetic focusing plates 10M. Further, the built-in coil 7 is disposed at a position that becomes the central portion of the range surrounded by the Hall elements 3 a to 3 d below the magnetic convergence plate 10.
As described above, even when the magnetic flux converging plate main body portion (10) and the portions (10M) corresponding to the protrusions 4a to 4d in FIG. 5 are formed as separate bodies, the same as in the second embodiment. The effect of this can be obtained.

<Modification 1>
The magnetic sensor of each of the embodiments described above can be applied even when the sensitivity adjustment of the Hall element is performed as a test, and can be applied even when the sensitivity is dynamically adjusted.
<Modification 2>
The magnetic sensor of each of the above embodiments may further include a hall element for measuring an external magnetic field.
That is, the magnetic sensor 41 shown in FIG. 10 includes an external magnetic field measuring Hall element 45 instead of the built-in coil 7 in the magnetic sensor 31 of the third embodiment.
The magnetic field generated by the built-in coils 5a to 5b is detected by the Hall elements 3a to 3d for sensitivity adjustment, and the sensitivity variation of the Hall element 45 for external magnetic field measurement is corrected using the detection signals of the Hall elements 3a to 3d. You may comprise.

<Manufacturing method>
Next, a method for manufacturing the magnetic sensor of this embodiment will be described.
FIG. 11 is a process diagram illustrating an example of a method for manufacturing the magnetic sensor 11 according to the first embodiment.
First, Hall elements 3a and 3b are formed on the semiconductor substrate 2 (FIG. 11A).
Next, the interlayer insulating layer 6 and the built-in coils 5a and 5b using metal wiring are formed on the semiconductor substrate 2 on which the Hall elements 3a to 3d are formed using a normal IC process (FIG. 11 ( b)).

Next, the interlayer insulating layer in the region inside the built-in coils 5a and 5b is etched using a resist to form the cavity 6a (FIG. 11C).
Next, the magnetic flux concentrating plate 4 is formed on the interlayer insulating layer 6 including the cavity 6a by plating (FIG. 11D).
Thereby, the magnetic sensor 11 in the first embodiment in which the magnetic converging plate is embedded in the hollow portion 6a and the protruding portions 4a and 4b are formed is formed.

  In the magnetic sensor 11 according to the first embodiment, in the case of a magnetic sensor including an adhesive layer or a protective layer between the magnetic convergence plate 4 and the interlayer insulating layer 6, as shown in FIG. Similarly to the manufacturing process shown, Hall elements 3a and 3b are formed on the upper portion of the semiconductor substrate 2 (FIG. 12A), the built-in coils 5a and 5b are formed (FIG. 12B), and the built-in coil 5a is etched. After the hollow portion 6a is formed inside 5b (FIG. 12C), magnetic converging plates corresponding to the protruding portions 4a and 4b are formed on the hollow portion 6a by plating (FIG. 12D).

Then, an adhesive layer or a protective layer 9 is formed on a plane including the magnetic convergence plate corresponding to the protruding portions 4a and 4b and the interlayer insulating layer 6. Then, the main body portion of the disk-shaped magnetic flux concentrating plate 4 is formed on the adhesive layer or the protective layer 9 again by plating (FIG. 12E).
Thereby, the magnetic sensor 11 including the adhesive layer or the protective layer 9 is formed between the magnetic flux concentrating plate 4 and the interlayer insulating layer 6.
In addition, when forming the magnetic sensor provided with the built-in coil 7 like the magnetic sensor 21 in 2nd Embodiment, what is necessary is just to produce the built-in coil 7 simultaneously when producing the built-in coils 5a and 5b.

  Further, when the built-in magnetic focusing plate 10M is provided like the magnetic sensor 31 in the third embodiment, the cavity portion 6a is created by the same procedure as the manufacturing process shown in FIG. 11 (FIG. 11C). ), A built-in magnetic flux concentrating plate 10M having a thickness about half the depth of the cavity 6a is formed in the cavity 6a, and an interlayer insulating layer is formed again thereon, and then an interlayer insulating layer of the cavity 6a is formed. The magnetic flux concentrating plate 10 may be formed on the interlayer insulating layer 6 including

In the above-described embodiment, the case where the Hall element is applied as the magnetic sensor element has been described. However, the present invention is not limited to the Hall element, and a magnetic field perpendicular to the magnetic convergence plate such as a magnetoresistive element can be detected. Any element can be applied.
In addition, the scope of the present invention is not limited to the illustrated and described exemplary embodiments, and includes all embodiments that provide the same effects as those intended by the present invention. Further, the scope of the invention can be defined by any desired combination of particular features among all the disclosed features.

2 Semiconductor substrate 3a-3d Hall element 4 Magnetic converging plates 5a-5d Built-in coil 6 Interlayer insulation layer 7 Built-in coils 11, 21, 31, 41 Magnetic sensor

Claims (9)

A magnetic sensor element formed on a semiconductor substrate;
A magnetic focusing plate provided above the magnetic sensor element;
A first built-in coil disposed between the magnetic sensor element and the magnetic focusing plate,
The magnetic converging plate has a protruding portion protruding toward the magnetic sensor element side,
The first built-in coil is a magnetic sensor disposed so as to surround the protruding portion. The magnetic converging plate has a disk shape;
The magnetic sensor according to claim 1, wherein the protrusion is provided in an end region of the magnetic focusing plate. Further comprising an interlayer insulating layer between the semiconductor substrate and the magnetic flux concentrating plate,
The magnetic sensor according to claim 1, wherein the protrusion and the first built-in coil are disposed in the interlayer insulating layer. The magnetic converging plate has a magnetic converging plate main body and the projecting portion formed separately from the magnetic converging plate main body,
The protrusion is disposed between the magnetic focusing plate body and the magnetic sensor element,
The magnetic sensor according to claim 1, wherein the first built-in coil is disposed so as to surround the protrusion.   5. The magnetic sensor according to claim 1, further comprising a second built-in coil different from the first built-in coil on a side of the magnetic sensor element in a central region of the magnetic focusing plate.   The magnetic sensor according to any one of claims 1 to 5, further comprising a coil current source that supplies a coil current to the first built-in coil or the second built-in coil. A magnetic sensor element formed on a semiconductor substrate;
A magnetic focusing plate provided above the magnetic sensor element;
A sensitivity adjusting built-in coil disposed between the magnetic sensor element and the magnetic focusing plate,
The magnetic converging plate has a protruding portion protruding toward the magnetic sensor element side,
The protrusion is a magnetic sensor arranged at a position to reinforce a magnetic field generated by the sensitivity adjustment built-in coil.   The magnetic sensor according to claim 1, wherein the magnetic sensor element is a Hall element. Forming a Hall element on a semiconductor substrate;
Forming an interlayer insulating layer having a sensitivity adjustment coil using metal wiring on a semiconductor substrate on which the Hall element is formed;
Removing the interlayer insulating layer in the inner region of the sensitivity adjustment coil to form a cavity portion;
Forming a magnetic flux concentrating plate on the cavity and the interlayer insulating layer;
A method for manufacturing a magnetic sensor.

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