This application claims the benefit of Japanese Priority Patent Application No. 2023-098082 filed on Jun. 14, 2023, the entire contents of which are incorporated herein by reference.
The present disclosure relates to a magnetic sensor device.
A magnetic sensor device includes a magnetic detection element made of a magnetic material. When an external force is applied to a magnetic material, a response to a magnetic field thereof fluctuates due to an inverse magnetostriction effect. In particular, while a tunnel magnetoresistance effect element has excellent output characteristics with a large MR ratio, output characteristics thereof tend to fluctuate due to an external force (for example, see JP-A-2005-277034).
The present disclosure has been made in view of these circumstances, and an object thereof is to provide a magnetic sensor device that has a high degree of freedom in designing a wiring layer and has stable output characteristics.
A magnetic sensor device according to one aspect of the present disclosure includes a plurality of magnetic detection element arrays formed in a first layer, and a wiring layer that is formed in a second layer different from the first layer and electrically connected to the plurality of magnetic detection element arrays. The plurality of magnetic detection element arrays include a first magnetic detection element array, and in a plane-normal direction from the second layer to the first layer, the wiring layer overlaps the first magnetic detection element array to encompass an entirety of the first magnetic detection element array, and the plurality of magnetic detection element arrays do not overlap an outline of the wiring layer.
According to the present disclosure, it is possible to provide a magnetic sensor device that has a high degree of freedom in designing a wiring layer and has stable output characteristics.
The accompanying drawings are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate example embodiments and, together with the specification, serve to explain the principles of the technology.
Among magnetic sensor devices, there is one in which a magnetic detection element is electrically connected to the outside using a wiring layer that is not flexible, rather than a bonding wire that is flexible. In such a magnetic sensor device, there is a risk that a thermal stress in the wiring layer, which expands or contracts due to a change in temperature, may act on the magnetic detection element. JP-A-2005-277034 discloses a semiconductor device in which, in order to solve the problem that, when the semiconductor device is heated, a stress occurs due to thermal deformation of a wiring layer and the stress in the wiring layer reaches a sensor element, a wiring portion is disposed at a position at which it does not overlap the sensor element in a thickness direction of a semiconductor chip.
However, in the semiconductor device of JP-A-2005-277034, since the wiring portion must be detoured to the position at which it does not overlap the sensor element in the thickness direction of the semiconductor chip, a layout of the wiring portion is greatly restricted.
The present disclosure has been made in view of these circumstances, and an object thereof is to provide a magnetic sensor device that has a high degree of freedom in designing a wiring layer and has stable output characteristics.
A preferred example embodiment will be described with reference to the accompanying drawings. In addition, in each figure, those with the same reference numerals have the same or similar configurations.
In the following, some example embodiments and modification examples of the technology are described in detail with reference to the accompanying drawings. Note that the following description is directed to illustrative examples of the disclosure and not to be construed as limiting the technology. Factors including, without limitation, numerical values, shapes, materials, components, positions of the components, and how the components are coupled to each other are illustrative only and not to be construed as limiting the technology. Further, elements in the following example embodiments which are not recited in a most-generic independent claim of the disclosure are optional and may be provided on an as-needed basis. The drawings are schematic and are not intended to be drawn to scale. Like elements are denoted with the same reference numerals to avoid redundant descriptions. As shown in
The sensor chip 3 may be fixed to the first surface 2A of the support substrate 2 with an adhesive or the like. As shown in
The sensor substrate 10 is, for example, a silicon substrate and may be disposed between the first surface 2A of the support substrate 2 and the protective film 20. The configuration of the magnetic sensor device 1 is not limited to the illustrated example, and may be a monolithic structure in which the sensor substrate 10 is omitted, and the support substrate 2 and the magnetic detection element arrays 30 are configured as an integral structure by photolithography. The protective film 20 may be an inorganic film mainly composed of silica (silicon dioxide, SiO2), or may be a layered film of an inorganic film mainly composed of silica and an inorganic film mainly composed of alumina (aluminum oxide Al2O3).
Each of the magnetic detection element arrays 30 may be configured of a plurality of magnetic detection elements E (shown in
The magnetic detection element arrays 30 may be disposed on the first surface 2A side of the support substrate 2 and formed in a first layer L1 on the first surface 2A side of the support substrate 2. The wiring layer 4 may be disposed on the first surface 2A side of the support substrate 2 and formed in a second layer L2 different from the first layer L1. A dummy pattern 4D (shown in
The second layer L2 is not particularly limited as long as it is a layer different from the first layer L1 and may be a plurality of layers. For example, the second layer L2 may be an upper surface of a first resin layer 51 (shown in
The wiring layer 4 may extend in parallel along the first surface 2A of the support substrate 2 and electrically connect the electrodes 2E of the support substrate 2 to the electrodes 3E provided on an upper surface 3A of the sensor chip 3 via a plurality of vias 40 extending in the plane-normal direction Z. The wiring layer 4 may be disposed to partially overlap the sensor substrate 10 in the plane-normal direction Z.
The sealing resin 5 may be disposed on the first surface 2A side of the support substrate 2 and may cover the sensor chip 3 and the wiring layer 4. The sealing resin 5 may be configured by layering a plurality of resin layers 51, 52, 53 (shown in
As shown in
As shown in
The magnetic sensor device 1 may detect a first component oriented in a direction parallel to the X direction of a magnetic field component MF, which is a magnetic field generated by the magnet 300 and applied to the magnetic sensor device 1, and generate a first detection signal representing an intensity of the first component, or may detect a second component oriented in a direction parallel to the Y direction of the magnetic field generated by the magnet 300 and generate a second detection signal representing an intensity of the second component. A processor (not shown) may calculate the angle θ that the magnetic field generated by the magnet 300 makes with respect to a reference direction DR by calculating an arctangent of a ratio of the first detection signal to the second detection signal.
The current sensor 400 may further include a feedback circuit 430, a current detector 440, and the like. The feedback circuit 430 may cause a feedback current for generating the second magnetic field MF2 to flow through the coil 420 on the basis of the magnetic field detection value S. The current detector 440 may detect a value of the feedback current flowing through the coil 420. The current detector 440 may be, for example, a resistor inserted in a current path of the feedback current. In that case, a potential difference across the resistor may correspond to a detected value of the feedback current. Since the detected value of the feedback current is proportional to a value of the electric current Itg of the bus bar 410, the value of the electric current Itg can be detected from the detected value of the feedback current.
The magnetic sensor device 1 of the present disclosure may be installed in an electronic device such as an information device and used as a magnetic compass that detects geomagnetism, may be used as part of an autofocus mechanism or an optical image stabilization mechanism of a camera module, may be used as an angle sensor that detects an angle formed by a magnetic field generated from a magnet with respect to a reference direction, or may be used as part of a current sensor that detects a value of an electric current flowing through a bus bar. According to these aspects, the magnetic sensor device 1 can be applied to various purposes.
The drive device 230 may be controlled on the basis of positional information of the lens 220 detected by a plurality of the magnetic sensor devices 1.
Specifically, the autofocus mechanism may detect a state in which a subject is in focus using an image sensor, autofocus sensor, or the like and move a lens in the Z direction relative to the image sensor. The optical image stabilization mechanism may detect camera shake using a gyro sensor or the like and move the lens in a U direction and/or a V direction with respect to the image sensor.
The camera module 200 shown in
In addition to the drive device 230 and the plurality of magnetic sensor devices 1, the autofocus mechanism and the optical image stabilization mechanism of the camera module 200 may include a processor that controls the drive device 230, an autofocus sensor that detects a state in which a subject is in focus, a gyro sensor that detects camera shake, and the like. A processor, an autofocus sensor, a gyro sensor, and the like (not shown) may be disposed outside the housing.
The lens 220 may be fixed inside the second holding member 242 formed in a cylindrical shape. The second holding member 242 may be housed for each lens 220 in the first holding member 241 formed in a box shape. At least one second magnet 243 may be fixed to the second holding member 242 in order for at least one magnetic sensor device 1 to detect positional information of the second holding member 242.
The drive device 230 may include a plurality of first coils 231, a plurality of second coils 232, a plurality of first magnets 233, and the like. The plurality of first coils 231 may be fixed to the housing 250. The plurality of second coils 232 may be fixed to the second holding member 242. The plurality of first magnets 233 may be fixed to the first holding member 241. Each of the plurality of first coils 231 may face the corresponding first magnet 233. Each of the plurality of second coils 232 may face the corresponding first magnet 233.
In the case of the autofocus mechanism, when an electric current flows through any second coil 232 in response to a command from the processor, due to the interaction between the magnetic field generated from the first magnet 233 and the magnetic field generated from the second coil 232, the second holding member 242 fixed to the second coil 232 may be moved in the Z direction. At least one magnetic sensor device 1 may generate a detection signal on the basis of a composite magnetic field in which a magnetic field generated from at least one second magnet 243 fixed to the second holding member 242 and a magnetic field generated from the first magnet 233 fixed to the first holding member 241 are combined together, and may transmit the detection signal to the processor. The processor may detect the positional information of the lens 220 in the Z direction from the detection signal and control the drive device 230 so that the subject is in focus.
In the case of the optical image stabilization mechanism, when an electric current flows through any first coil 231 in response to a command from the processor, due to the interaction between the magnetic field generated from the first magnet 233 and the magnetic field generated from the first coil 231, the first holding member 241 fixed to the first magnet 233 may be moved in the U direction and/or the V direction. Each of the plurality of magnetic sensor devices 1 may generate a detection signal on the basis of a position of the corresponding first magnet 233 and transmit it to the processor. The processor may detect the positional information of the lens 220 in the U direction and the V direction from the detection signal and control the drive device 230 to correct camera shake.
Next, the magnetic sensor device 1 of the present disclosure will be described in detail with reference to
As shown in
In the examples shown in
As shown in
For example, in a first example shown in
Also, the expression “encompass the entire first magnetic detection element array 31” may be replaced to “encompass all the magnetic detection elements E that constitute the first magnetic detection element array 31.” Similarly, the expression “encompass the entire second magnetic detection elements 32” may be replaced to “encompass all the magnetic detection elements E that constitute the second magnetic detection element array 32.”
As described above, each of the plurality of magnetic detection element arrays 30 may be configured of a plurality of magnetic detection elements E arranged in a matrix. In each of the magnetic detection element arrays 30, a plurality of magnetic detection elements E may be connected in series. In the illustrated example, in each of the magnetic detection element arrays 30, a plurality of magnetic detection elements E may be arranged at equal intervals. The magnetic detection element arrays 30 and the electrodes 3E may be electrically connected to each other by a wiring W formed in the first layer L1. The magnetic detection element arrays 30 and other magnetic detection element arrays 30 may be also electrically connected to each other by the wiring W.
As described above, the dummy pattern 4D is formed in the second layer L2 similarly to the wiring layer 4. However, unlike the wiring layer 4, the dummy pattern 4D is not electrically connected to the plurality of magnetic detection element arrays 30. Further, the dummy pattern 4D is not electrically connected to the wiring layer 4 either.
In contrast, in the examples of the present disclosure shown in
Further, in the examples shown in
When resistance ratios of the first magnetic detection element array 31 and the second magnetic detection element array 32 change, the equilibrium conditions of the bridge circuit change, and the output characteristics of the magnetic sensor device 1 become unstable. Similarly, when the resistance ratios of the third magnetic detection element array 33 and the fourth magnetic detection element array 34 change, the equilibrium conditions of the bridge circuit change, and the output characteristics of the magnetic sensor device 1 become unstable.
According to the first example, the first magnetic detection element array 31 and the second magnetic detection element array 32 are less likely to be affected by the thermal stress of the wiring layer 4, and the equilibrium conditions of the bridge circuit are less likely to change. Similarly, the third magnetic detection element array 33 and the fourth magnetic detection element array 34 are less likely to be affected by the thermal stress of the wiring layer 4, and the equilibrium conditions of the bridge circuit are less likely to change. For that reason, the output characteristics of the magnetic sensor device 1 can be stabilized.
In the second example shown in
Similarly, in the plane-normal direction Z, the wiring layer 4 may overlap to encompass one of the third magnetic detection element array 33 and the fourth magnetic detection element array 34 (in the illustrated example, the fourth magnetic detection element array 34), and the dummy pattern 4D may overlap to encompass the other magnetic detection element array 33 (in the illustrated example, the third magnetic detection element array 33).
According to the second example, similarly to the first example, the first magnetic detection element array 31 and the second magnetic detection element array 32 are less likely to be affected by the thermal stress of the wiring layer 4 and the dummy pattern 4D, and the equilibrium conditions of the bridge circuit are less likely to change. The third magnetic detection element array 33 and the fourth magnetic detection element array 34 are also less likely to be affected by the thermal stress of the wiring layer 4 and the dummy pattern 4D, and the equilibrium conditions of the bridge circuit are less likely to change. For that reason, the output characteristics of the magnetic sensor device 1 can be stabilized.
When it is difficult to dispose the wiring layer 4 to encompass the entire second magnetic detection element array 32, the dummy pattern 4D can encompass the entire second magnetic detection element array 31 instead of the wiring layer 4, and thus the degree of freedom in designing the wiring layer 4 can be increased. Since the plurality of magnetic detection element arrays 30 do not overlap the outline of the wiring layer and the outline of the dummy pattern 4D, it is possible to provide the magnetic sensor device 1 that is less likely to be affected by the thermal stress of the wiring layer 4 and the dummy pattern 4D and has stable output characteristics. Since the wiring layer 4 may or may not encompass the entire first magnetic detection element array 30, the degree of freedom in designing the wiring layer 4 can be further increased.
Also, since the wiring layer 4 overlaps the first magnetic detection element array 31 to encompass the entire first magnetic detection element array 31, the wiring layer 4 can be disposed so that all the magnetic detection element arrays 30 do not overlap the outline of the wiring layer 4 without detouring the first magnetic detection element array 31. The degree of freedom in designing the wiring layer 4 can be increased as compared to the case in which all the magnetic detection element arrays 30 must be detoured.
The example embodiments described above are intended to facilitate understanding of the present disclosure, and are not intended to be interpreted as limiting the present disclosure. Each of the elements included in the example embodiments, as well as their arrangements, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, and can be changed as appropriate. Further, it is possible to partially replace or combine the structures shown in different example embodiments.
Number | Date | Country | Kind |
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2023-098082 | Jun 2023 | JP | national |