JP2021047083A - Magnetic sensor - Google Patents

Abstract

To provide a magnetic sensor which allows a simple structure.SOLUTION: A magnetic sensor 1 comprises: a plurality of magnetoresistive elements 3a to 3d connected in the form of a bridge via electrical wiring 2; and a three-dimensional crossover 18 on which a plurality of pieces of electrical wiring 2 are overlapped. First electrical wiring 2a, one of the electrical wiring 2 on the three-dimensional crossover 18, is formed so as to pass through annular sensor wiring 19 that generates resistance according to a magnetic field. Second electrical wiring 2b, the other of the electrical wiring 2 on the three-dimensional crossover 18, is arranged on the sensor wiring 19 while being insulated.SELECTED DRAWING: Figure 3

Description

The present invention relates to a magnetic sensor that detects a change in a magnetic field and outputs an electric signal according to the detected magnetic field.

Conventionally, a magnetic sensor having a structure in which four magnetoresistive elements are combined in a bridge shape is well known (see Patent Document 1 and the like). In this type of magnetic sensor, the resistance value changes according to the applied magnetic field, and a detection signal based on the detected magnetic field is output. Such a magnetic sensor is used, for example, when switching between two positions (on position and off position) of a detection target and when linearly detecting the position of a detection target.

Japanese Unexamined Patent Publication No. 2011-027495

By the way, when the wiring structure of the magnetic sensor is a one-layer structure, if a wiring pattern is to be provided without intersecting the wirings, complicated wiring routing is required. Therefore, there is a problem that the chip size, the number of wires, and the number of wire bonding pads of the magnetic sensor increase. Further, when the wiring is crossed, it is necessary to make the circuit of the magnetic sensor into two-layer wiring, so that the number of steps is increased accordingly. Therefore, since the chip unit price and lead time of the substrate increase, there is a fact that it is not an effective countermeasure.

An object of the present invention is to provide a magnetic sensor that enables simplification of the structure.

A magnetic sensor that solves the above-mentioned problems includes a plurality of magnetic resistance elements connected in a bridge shape via electrical wiring and a three-dimensional intersection in which the plurality of electrical wirings are arranged so as to overlap each other. The first electrical wiring, which is one of the electrical wirings, is formed so as to pass through an annular sensor wiring that generates a resistance value according to the magnetic field, and the second electrical wiring, which is the other electrical wiring of the three-dimensional intersection, is formed. It is arranged on the sensor wiring via an insulating portion.

According to the present invention, the structure of the magnetic sensor can be simplified.

The bridge circuit diagram of the magnetoresistive element of one embodiment. Schematic diagram of position detection by a magnetic sensor. Layout diagram of the circuit pattern of the magnetic sensor. Layout of the common centroid structure. Schematic diagram of a grade separation. FIG. 5 is a sectional view taken along line II-II of FIG. Action diagram showing the flow of magnetic field and current. Layout diagram of the circuit pattern of the conventional positioning magnetic sensor.

Hereinafter, an embodiment of the magnetic sensor will be described with reference to FIGS. 1 to 8.
As shown in FIG. 1, the magnetic sensor 1 includes a plurality of magnetoresistive elements 3 connected in a bridge shape via an electric wiring 2. The magnetic sensor 1 of this example includes a circuit in which four elements of a first magnetic resistance element 3a, a second magnetic resistance element 3b, a third magnetic resistance element 3c, and a fourth magnetic resistance element 3d are combined in a full bridge shape. The voltage of the power supply 4 is applied to the set of the first magnetoresistive element 3a and the fourth magnetoresistive element 3d connected in series and the set of the second magnetoresistive element 3b and the third magnetoresistive element 3c connected in series. It is applied. The resistance value of the magnetoresistive element 3 changes according to the magnetic field applied to the magnetoresistive element 3, and the voltage at the midpoint (node) of the first magnetoresistive element 3a and the fourth magnetoresistive element 3d and the second magnetism The difference between the voltage at the midpoint (node) of the resistance element 3b and the third magnetic resistance element 3c is output as the detection signal Sout.

As shown in FIG. 2, the magnetic sensor 1 detects the magnetic flux of the magnet 6 that approaches and separates according to the movement of the detection target 5. The magnet 6 of this example reciprocates in the sliding direction (arrow R direction in the figure) with respect to the magnetic sensor 1 in response to the movement of the detection target 5. The magnetic sensor 1 detects a magnetic field according to the distance from the magnet 6 and outputs a detection signal Sout according to the detected magnetic field. The magnetic sensor 1 of this example detects two positions, that is, a position where the magnet 6 is close to the magnet 6 and a position where the magnet 6 is separated from each other, that is, two states of on and off.

As shown in FIG. 3, each of the first magnetoresistive element 3a to the fourth magnetoresistive element 3d is constructed from a plurality of elements in order to arrange the arrangement so that the detection variation of the magnetic flux can be suppressed. In the case of this example, the first magnetoresistive element 3a is composed of an A element and a D element. The second magnetoresistive element 3b is composed of a B element and a C element. The third magnetoresistive element 3c is composed of an E element and an H element. The fourth magnetoresistive element 3d is composed of an F element and a G element.

As shown in FIG. 4, as an arrangement example of the arrangement of a plurality of elements, for example, there is a common centroid arrangement in which the first magnetoresistive element 3a to the fourth magnetoresistive element 3d are point-symmetrical. In the case of this example, the A element and the D element of the first magnetoresistive element 3a and the F element and the G element of the fourth magnetoresistive element 3d are combined and arranged point-symmetrically. Further, the combination of the B element and the C element of the second magnetoresistive element 3b and the E element and the H element of the third magnetoresistive element 3c are arranged point-symmetrically.

As shown in FIG. 3, the magnetic resistance patterns 9 of the A element to the H element are mounted on the substrate 10 of the magnetic sensor 1. The substrate 10 is provided with a pad portion 11 for connecting the magnetic sensor 1 and an external terminal (not shown). The pad portion 11 is, for example, a bonding pad. The pad portion 11 has a power supply terminal 12 connected to the power supply 4, a GND terminal 13 connected to the ground, a + side output terminal 14 from which the positive side output is drawn out, and a negative side from which the negative side output is drawn out. An output terminal 15 is provided. The magnetic sensor 1 outputs the difference in voltage between the + side output terminal 14 and the − side output terminal 15 as a detection signal Sout.

The A element to the H element are each connected through an electric wiring 2 provided on the substrate 10. The electrical wiring 2 is preferably a wiring containing, for example, aluminum and copper.
The magnetic sensor 1 includes a grade separation portion 18 in which a plurality of electrical wirings 2 are arranged so as to overlap each other. In the case of this example, the grade separation portion 18 connects the electric wiring 2 (hereinafter referred to as the first electric wiring 2a) connecting the F element and the + side output terminal 14 (D element) with the E element and the-output terminal 15. It is formed by intersecting the electrical wiring 2 (hereinafter referred to as the second electrical wiring 2b).

As shown in FIGS. 5 and 6, the first electric wiring 2a is formed so as to pass through an annular sensor wiring (hereinafter, referred to as the first sensor wiring 19) that generates a resistance value according to a magnetic field. In the case of this example, the first electrical wiring 2a includes a branched first wiring portion 20a and a second wiring portion 20b, and the first wiring portion 20a and the second wiring portion 20b are connected via the first sensor wiring 19. Has been done. The annular first sensor wiring 19 is preferably formed in a perfect circle. The first sensor wiring 19 is preferably formed of the same material as the first magnetoresistive element 3a to the fourth magnetoresistive element 3d, that is, the A element to the H element. The material of the first sensor wiring 19 is preferably a material containing, for example, nickel iron. The first wiring portion 20a and the second wiring portion 20b are arranged side by side in a straight line. Further, the first electric wiring 2a and the second electric wiring 2b are arranged at orthogonal angles.

As shown in FIG. 6, a contact portion 21 projecting toward the first sensor wiring 19 side is formed on the back surface of the end portion of the first wiring portion 20a, and the first wiring portion 20a is first connected via the contact portion 21. It is connected to the sensor wiring 19. A contact portion 22 protruding toward the first sensor wiring 19 is formed on the back surface of the end portion of the second wiring portion 20b, and the second wiring portion 20b is connected to the first sensor wiring 19 via the contact portion 22. There is. Further, the first sensor wiring 19 is arranged on the same substrate 10 as the first magnetoresistive element 3a to the fourth magnetoresistive element 3d.

The second electrical wiring 2b is arranged above the first sensor wiring 19 via the insulating portion 23. By doing so, the second electrical wiring 2b is ensured to be insulated from the first sensor wiring 19 at the grade separation portion 18. The material of the insulating portion 23 does not matter as long as it can secure the insulation between the second electrical wiring 2b and the first sensor wiring 19.

As shown in FIGS. 1 and 3, the annular first sensor wiring 19 is provided on the substrate 10 of the magnetic sensor 1 in order to suppress the influence of the provision of the first sensor wiring 19 on the detection signal Sout. It is arranged symmetrically with the sensor wiring (hereinafter referred to as the second sensor wiring 26). When a grade separation portion 18 is provided in the first electrical wiring 2a connecting the F element and the + side output terminal 14 as in this example, the electrical wiring 2 symmetrical to this, that is, the C element and the − side output terminal 15 The second sensor wiring 26 is provided in the third electrical wiring 2c that connects the two. The second sensor wiring 26 does not cross over a plurality of electrical wirings 2 in a three-dimensional manner, but is simply an annular wiring portion interposed in the third electrical wiring 2c.

Next, the operation of the magnetic sensor 1 of the present embodiment will be described with reference to FIGS. 7 and 8.
FIG. 8 illustrates an example of the magnetic sensor 1 that does not use the grade separation portion 18. As shown in the figure, in the case of the magnetic sensor 1 that does not use the grade separation portion 18, since the F element cannot be connected to the D element by a single layer wiring, another + side output terminal 29 is provided on the pad portion 11. Therefore, it becomes necessary to connect the + side output terminals 14 and 29 outside the sensor chip of the magnetic sensor 1. In this case, there is a problem that the wiring needs to be routed separately and the number of bonding pads increases.

On the other hand, in the magnetic sensor 1 of this example, since the F terminal can be directly connected to the + side output terminal 14 through the grade separation portion 18, the electrical wiring 2 does not need to be routed and the number of bonding pads increases. There is no such thing. Therefore, it leads to the simplification of the sensor configuration of the magnetic sensor 1 and the reduction of the manufacturing cost.

As shown in FIG. 7, for example, when a magnetic field (magnetic field) is applied to the first sensor wiring 19 and an electric wiring current Ia flowing to the right of the paper surface flows through the first electric wiring 2a, electricity flowing through the second wiring portion 20b. The wiring current Ia flows as the sensor wiring current Ib flowing through the first sensor wiring 19, and takes a path that flows out to the first wiring portion 20a. When the sensor wiring current Ib flows through the first sensor wiring 19, this may cause the detection variation of the magnetic sensor 1.

However, in the case of this example, since the sensor wiring current Ib becomes an arc by forming the first sensor wiring 19 in an annular shape, the resistance value generated in the first sensor wiring 19 is constant regardless of the change in the angle of the magnetic vector. Become. Therefore, even if the magnetic sensor 1 is provided with the first sensor wiring 19, it is possible to make it difficult to affect the deterioration of the detection accuracy.

Further, another second sensor wiring 26 having the same pattern as the first sensor wiring 19 of the grade separation portion 18 is arranged at a symmetrical position of the grade separation portion 18. If the first sensor wiring 19 and the second sensor wiring 26 are arranged symmetrically (left-right symmetrical arrangement) in this way, the influence of the resistance component of the first sensor wiring 19 of the solid intersection 18 on the sensor output (offset voltage) is exerted. It is possible to reduce it. That is, the first sensor wiring 19 and the second sensor wiring 26 take the same resistance value, and the resistance components are offset. Therefore, it further contributes to ensuring the detection accuracy of the magnetic sensor 1.

According to the magnetic sensor 1 of the above embodiment, the following effects can be obtained.
(1) The magnetic sensor 1 includes a plurality of magnetoresistive elements 3 connected in a bridge shape via an electrical wiring 2 and a grade separation portion 18 in which the plurality of electrical wirings 2 are arranged so as to overlap each other. The first electric wiring 2a, which is one electric wiring 2 of the three-dimensional intersection 18, is formed so as to pass through the annular first sensor wiring 19 that generates a resistance value according to the magnetic field, and the other electricity of the three-dimensional intersection 18. The second electrical wiring 2b, which is the wiring 2, is arranged on the first sensor wiring 19 via the insulating portion 23.

According to this example, since it is possible to provide the grade separation portion 18 of the electrical wiring 2 on the same layer, the substrate 10 can be made into a plurality of layers (for example, two layers) in order to cross the electrical wiring 2 in a grade separation. Further, it is not necessary to take a configuration such as increasing the number of wires and the number of pads without using the grade separation of the electric wiring 2. Therefore, it is possible to reduce the size of the chip of the magnetic sensor 1, reduce the number of wires, and reduce the number of bonding pads (number of wire bonding pads). Therefore, the structure of the magnetic sensor 1 can be simplified.

(2) The first electric wiring 2a and the second electric wiring 2b are arranged so as to be orthogonal to each other. Therefore, the first electric wiring 2a and the second electric wiring 2b arranged at the grade separation can be arranged in a well-balanced manner.

(3) The first sensor wiring 19 (second sensor wiring 26) is mounted on the same substrate 10 as the magnetoresistive element 3. Therefore, it is not necessary to have a plurality of layers of the substrate 10, which further contributes to the simplification of the structure of the magnetic sensor 1.

(4) The first sensor wiring 19 (second sensor wiring 26) is formed in a perfect circle. Therefore, the resistance value remains constant regardless of the angle at which the magnetic field is applied to the first sensor wiring 19 (second sensor wiring 26), so that the sensor output by the first sensor wiring 19 (second sensor wiring 26) can be obtained. The influence of can be suppressed to a low level.

(5) The magnetic sensor 1 includes a second sensor wiring 26 symmetrically arranged with respect to the first sensor wiring 19 of the grade separation portion 18. Therefore, it is possible to reduce the influence of the sensor output due to the resistance component of the first sensor wiring 19 of the grade separation portion 18. Therefore, it contributes to ensuring the detection accuracy of the magnetic sensor 1.

In addition, this embodiment can be implemented by changing as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
[About sensor wiring (first sensor wiring 19)]
The first sensor wiring 19 is not limited to a perfect circle, and may be changed to another shape such as an ellipse.

-The first sensor wiring 19 may be provided at a plurality of locations. In this case, each first sensor wiring 19 may be formed in a different shape.
The first sensor wiring 19 may be formed on a substrate 10 different from the magnetoresistive element 3.

[About the second sensor wiring 26]
The second sensor wiring 26 may be a grade separation portion in which a plurality of wirings are overlapped.
The second sensor wiring 26 may have a shape different from that of the first sensor wiring 19.

-For example, when a plurality of grade separation portions 18 are provided, a plurality of second sensor wirings 26 may be formed so as to correspond to each grade separation portion 18.
[About magnetoresistive element 3]
The arrangement of the magnetoresistive elements 3 is not limited to the common centroid arrangement, and any arrangement may be sufficient as long as a plurality of elements (each of the elements A to H) are arranged in a predetermined pattern.

The magnetoresistive element 3 is not limited to the full bridge, and may be, for example, a half bridge.
-The bridge circuit of the magnetoresistive element 3 is not limited to one, and a plurality of bridge circuits may be provided.
The magnetoresistive element 3 is not limited to being constructed from a plurality of elements (each element of A to H), and may have a structure in which the first magnetoresistive element 3a to the fourth magnetoresistive element 3d are each composed of one element. ..

[About grade separation 18]
-The grade separation portion 18 may have a structure in which three or more electric wirings 2 are overlapped.
The number of layers of the grade separation portion 18 is not particularly limited, and an appropriate number of layers can be adopted as needed.

-A plurality of grade separation portions 18 may be provided.
[About electrical wiring 2]
-The first electric wiring 2a separated into two is not limited to being arranged on the same straight line, but may be arranged on a non-straight line.

-The first electric wiring 2a and the second electric wiring 2b may be arranged non-orthogonally.
[About detection target 5]
-The detection target 5 is not limited to a sliding member, and may be, for example, a rotating member.

-The detection target 5 may be various devices or devices.
[About magnetic sensor 1]
The magnetic sensor 1 is not limited to a sensor that detects two positions of the detection target 5 approaching and separating from each other, and may be a sensor that linearly detects the position of the detection target 5.

-The magnetic sensor 1 can be used in various devices and devices.

1 ... Magnetic sensor, 2 ... Electrical wiring, 2a ... 1st electrical wiring, 2b ... 2nd electrical wiring, 3 ... Magneto resistance element, 3a ... 1st magnetoresistive element, 3b ... 2nd magnetoresistive element, 3c ... 3rd Magneto resistive element, 3d ... 4th magnetoresistive element, 10 ... Substrate, 18 ... Solid intersection, 19 ... 1st sensor wiring, 23 ... Insulation part, 26 ... 2nd sensor wiring.

Claims (5)

Multiple magnetoresistive elements connected in a bridge shape via electrical wiring,
It is provided with a grade separation portion in which a plurality of the electrical wirings are arranged so as to overlap each other.
The first electric wiring, which is one of the three-dimensional intersections, is formed so as to pass through an annular sensor wiring that generates a resistance value according to a magnetic field, and is the second electric wiring of the other three-dimensional intersection. The electrical wiring is a magnetic sensor arranged on the sensor wiring via an insulating portion. The magnetic sensor according to claim 1, wherein the first electrical wiring and the second electrical wiring are arranged so as to be orthogonal to each other. The magnetic sensor according to claim 1 or 2, wherein the sensor wiring is mounted on the same substrate as the magnetoresistive element. The magnetic sensor according to any one of claims 1 to 3, wherein the sensor wiring is formed in a perfect circle. The magnetic sensor according to any one of claims 1 to 4, further comprising a second sensor wiring symmetrically arranged with respect to the first sensor wiring which is the sensor wiring of the three-dimensional intersection.

Images