JP2015194389A - Magnetic field detection device and multi piece substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small magnetic field detection device.SOLUTION: The magnetic field detection device comprises: a substrate; a magnetic field detector having the normal of the principal surface of the substrate as a normal and arranged on a first plane above the principal surface of the substrate; a permanent magnet having the normal of the principal surface of the substrate different from the first plane as a normal and arranged in the magnetization direction on a second plane separated from the substrate above the principal surface of the substrate; an electrode terminal arranged on a third plane different from the first and second planes, separated from the first and second flat planes and the principal surface of the substrate, having the normal of the principal surface of the substrate as a normal, separated from the substrate above the principal surface of the substrate and connected with the magnetic field detector; and an internal wiring connected with the electrode terminal and the magnetic field detector. The magnetic field detector, the permanent magnet, the electrode terminal and the internal wiring are integrally formed above the principal surface of the substrate.

Description

  The present invention relates to a magnetic field detection device for detecting a magnetic field and a multi-sided substrate.

  Magnetic sensors using magnetoresistive elements (hereinafter also referred to as GMR / TMR elements) have been proposed and put into practical use. The GMR / TMR element includes a magnetoresistive film including a pinned layer whose magnetization direction is pinned in a predetermined direction, and a free layer whose magnetization direction changes corresponding to an external magnetic field. Is added, the resistance value changes according to the relative relationship between the magnetization direction of the pinned layer and the magnetization direction of the free layer. In the magnetic sensor, the strength of the external magnetic field can be measured by measuring the resistance value of the GMR / TMR element.

  For example, in Patent Document 1, in order to maintain the uniaxial anisotropy of the free layer, a permanent magnet (bias magnet) composed of a ferromagnetic material or the like in the vicinity of the bent portion of the GMR element, that is, on both ends of the magnetoresistive film. Has been proposed.

  Further, Patent Document 2 discloses a method of detecting a gradient by providing a Wheatstone bridge using four magnetoresistive elements and a compensation current line and arranging them in an external magnetic field. This combination reduces the influence of external disturbing magnetic fields and environmental temperature.

JP 2011-196798 A Japanese National Patent Publication No. 10-506193

  However, regarding the magnetic field detection device, in addition to increasing the accuracy of the overall configuration, further miniaturization is required. The present invention has been made in view of such a problem, and an object thereof is to provide a small magnetic field detection device.

  The present invention relates to a substrate, a magnetic field detector disposed on a first plane separated from the substrate on the main surface of the substrate having a normal to the main surface of the substrate as a normal, and a substrate different from the first plane Unlike the first and second planes, a permanent magnet having a magnetization direction arranged in a second plane spaced from the substrate on the main surface of the substrate having a normal to the main surface of The first and second planes are arranged on a third plane separated from the substrate on the main surface of the substrate having a normal to the main surface of the substrate farther from the main surface of the substrate than the first and second planes; It has an electrode terminal to be connected and an internal wiring connected to the electrode terminal and the magnetic field detection unit, and the magnetic field detection unit, the permanent magnet, the electrode terminal, and the internal wiring are integrally formed on the main surface of the substrate. It is a magnetic field detection device. By adopting such a configuration, the size can be reduced as compared with the conventional magnetic field detection device.

  Furthermore, in the present invention, the magnetic field detection unit, the permanent magnet, and the electrode terminal are separated from each other by an insulating layer, and short-circuiting (electrical) between the respective units can be prevented.

  Furthermore, in the present invention, when the substrate is made of, for example, a conductive material, an insulating layer is formed on the main surface of the substrate, so that a short circuit (electrical) via the substrate can be prevented.

  Furthermore, in the present invention, the permanent magnet is generally a rectangular parallelepiped, and the longitudinal direction thereof is the magnetization direction of the magnetic pole, so that demagnetization of the permanent magnet can be prevented.

  Furthermore, in the present invention, the projection surface in the normal direction of the main surface of the permanent magnet substrate includes all the projection surfaces in the normal direction of the main surface of the substrate of the magnetic field detection unit. Compared with the case where it is placed on the side, the element area can be reduced.

  Furthermore, in the present invention, the normal line of the main surface of the substrate is the normal line, and the first surface is different from the first to third planes, and is disposed on the fourth plane existing between the main surface of the substrate and the third plane. And a compensation current line for supplying a compensation current for applying a compensation magnetic field in a direction to cancel the external magnetic field detected by the magnetic field detection unit to the magnetic field detection unit. By adopting such a configuration, the change in the output voltage caused by the environmental temperature and external noise can be further reduced, so that the magnetic field detection accuracy is improved. Further, the permanent magnet and the electrode terminal extending in the longitudinal direction of the permanent magnet may have an overlap.

  Further, in the present invention, the permanent magnet and the electrode terminal connected to the compensation current line extending in the longitudinal direction of the permanent magnet as viewed from the normal line of the main surface of the substrate may have an overlap. May be a multi-sided substrate in which a plurality of are present on the main surface of the substrate.

  Furthermore, in the present invention, a magnetic field detection device in which the magnetization direction is determined by applying a magnetizing magnetic field to a multi-sided substrate, or the magnetization direction is determined by applying a magnetizing magnetic field to a multi-sided substrate. Therefore, there is no variation in the individual magnetization directions as compared with the case where magnetization is performed after the multi-sided substrate is separated.

  According to the present invention, it is possible to provide a small magnetic field detection device.

FIG. 1 is a top view of the magnetic field detection device (a surface including the permanent magnet 9). FIG. 2 is a cross-sectional view (line A-B in FIG. 1) of the magnetic field detection device. FIG. 3 is a top view of the magnetoresistive effect element 20 and the internal wiring 2. FIG. 4 is a top view of the magnetoresistive effect element 20 and the compensation current line 4.

  FIG. 1 is a top view of a magnetic field detection device 1 according to the present embodiment, and a portion surrounded by a dotted line indicates the magnetic field detection device 1. FIG. 2 is a cross-sectional view taken along the line A-B in FIG. 1, and a portion surrounded by a dotted line indicates the magnetic field detection device 1. As shown in FIG. 2, a magnetic field detection unit 20, which is a magnetoresistive element 20, is arranged on a first plane separated from the substrate 5 on the main surface of the substrate 5 with the normal line of the main surface of the substrate 5 as a normal line. Is done. Further, unlike the first plane, a second plane spaced from the substrate on the main surface of the substrate 5 having the normal line of the main surface of the substrate 5 as a normal line is attached to a bias magnetic field application described later. A permanent magnet 9 having a magnetic direction is arranged. Further, unlike the first and second planes, the substrate on the main surface of the substrate 5 having the normal line of the main surface of the substrate 5 away from the main surface of the substrate 5 as compared with the first and second planes. The electrode terminal 3 is disposed on a third plane spaced apart from each other. FIG. 3 is a plan view of the first plane, showing the magnetoresistive effect element 20 and a part of the internal wiring 2. The end portion of the internal wiring 2 shown in FIG. 3 is connected to the electrode terminal 3 of FIG. 1 by a via (a part of the internal wiring 2) rising in the normal direction of the main surface of the substrate 5. Each configuration will be described below.

  The substrate 5 is made of a semiconductor such as silicon or AlTiC (Altic), a conductor, or an insulator such as alumina or glass, and the form thereof is not particularly limited.

  The magnetoresistive effect element 20 included in the magnetic field detection device 1 arranged in the first plane is generally an intermediate layer composed of a pinned layer having a magnetization direction fixed in a fixed direction and a nonmagnetic conductor or insulator. A layered body including a layer and a free layer whose magnetization direction changes according to an external magnetic field, and an intermediate layer sandwiched between the fixed layer and the free layer. When the intermediate layer is a conductor, it is generally called a GMR (giant magnetoresistive element), and when it is an insulator, it is called a TMR (tunnel type magnetoresistive element). The resistance of the magnetoresistive element 20 changes according to the angle between the magnetization direction of the pinned layer and the average magnetization direction of the free layer. The free layer is made of a soft magnetic film such as NiFe, for example. The intermediate layer is made of, for example, a conductor film such as Cu or an insulator film such as alumina / magnesium oxide. The fixed layer includes an antiferromagnetic film and a magnetization fixed film, and the magnetization fixed film is in contact with the intermediate layer. The antiferromagnetic film is made of, for example, an antiferromagnetic Mn alloy such as IrMn or PtMn. For example, the magnetization fixed layer may be made of a ferromagnetic material such as CoFe or NiFe, or may be configured such that a Ru thin film layer is sandwiched between CoFe and the like.

  Next, the function of the permanent magnet 9 will be described. The soft magnetic film constituting the free layer constitutes a plurality of magnetic domains having different magnetization directions in the film surface when there is no external magnetic field. Since the magnetization direction of each magnetic domain changes according to the history of the external magnetic field applied to the soft magnetic film (magnetic hysteresis), the magnetization direction of the free layer, which is the average value of the magnetization directions of each magnetic domain in the absence of a magnetic field, is It does not take a certain direction and has variations. Therefore, when the magnetization direction of the free layer does not take a constant direction, the resistance of the magnetoresistive effect element 20 in a non-magnetic field state does not take a constant value, which is not preferable. In addition, although the magnetization direction of the free layer changes due to the application of an external magnetic field, the phenomenon of change in magnetization direction varies depending on the magnetic domain, that is, Barkhausen noise occurs. In order to avoid these events, it is necessary to stabilize the magnetization direction of the free layer. Here, in order to stabilize the magnetization direction, a permanent magnet 9 having a magnetization direction is arranged on the second plane. In addition, it is preferable to arrange the permanent magnet 9 so that the magnetization direction is aligned with the longitudinal direction of the free layer in the non-magnetic field state. Here, as shown in FIG. 3, when viewed from the normal direction of the substrate 5, the magnetoresistive element 20 and the permanent magnet 9 are rectangular, and their longitudinal directions are parallel to each other. Therefore, by magnetizing the permanent magnet 9 in the longitudinal direction, it becomes possible to align the magnetization in the longitudinal direction of the free layer of the magnetoresistive element 20. Since the magnetic domain from the permanent magnet 9, that is, the bias magnetic field, causes the magnetic domain of the free layer to be in a single domain state, particularly when the external magnetic field is orthogonal to the longitudinal direction of the free layer, generation of magnetic hysteresis and Barkhausen noise can be suppressed. For example, the permanent magnet 9 is preferably an alloy mainly composed of Co, a rare earth magnet, or a ferrite magnet.

  The electrode terminal 3 is disposed on the third plane and is connected to one end of the internal wiring 2. The other end of the internal wiring 2 is connected to the magnetoresistive effect element 20, and the resistance change of the magnetoresistive effect element 20 can be taken out as an output. The electrode terminal 3 and the internal wiring 2 are preferably made of a conductive metal such as Au, Al, Ag, or Cu, or an alloy thereof.

  On the substrate 5, the magnetic field detection unit that is the magnetoresistive effect element 20, the permanent magnet 9, and the internal wiring 2 are arranged, and when viewed from the normal direction of the substrate, the magnetic field detection unit that is the magnetoresistive effect element 20, The electrode terminals 3 are arranged outside the permanent magnet 9 and the internal wiring 2. Each part can be formed with fine dimensions on the order of microns by being integrally formed by a thin film process using processing by photolithography. Furthermore, the distance between the permanent magnet 9 and the magnetic field detection unit is determined by forming them integrally. Therefore, compared with the case where the permanent magnet 9 is not integrally formed and the permanent magnet 9 is arranged on a plane above the third plane on which the electrode terminals 3 are arranged, the magnetic field detection unit 20 which is the magnetoresistive effect element 20 is used. Since the magnetic field of the permanent magnet 9 exerted becomes stronger, the permanent magnet 9 can be reduced in size in a plane parallel to the main surface of the substrate 5. For these reasons, the magnetic field detection device 1 can be downsized. Further, since the assembly error of the permanent magnet 9 hardly occurs, individual differences in the bias magnetic field direction can be suppressed.

  Here, the first plane and the second plane have been described on the assumption that the first plane exists on the substrate side with respect to the second plane, but the second plane exists on the substrate 5 side with respect to the first plane. You may do it. In other words, the permanent magnet 9 and the magnetic field detection unit 20 that is the magnetoresistive effect element 20 may be present on the upper surface of the main surface of the substrate in order from the main surface of the substrate 5. Even in this case, the distance between the permanent magnet 9 and the magnetic field detection unit 20 that is the magnetoresistive effect element 20 is set as compared with the case where the permanent magnet 9 is arranged on a plane above the third plane on which the electrode terminals 3 are arranged. Since the electrode terminal 3 is sufficiently thick, the distance between the permanent magnet 9 and the magnetic field detector can be set to a small value, and the permanent magnet 9 can be downsized.

  In terms of actual manufacturing restrictions, it is preferable that the magnetic field detection unit 20 that is the magnetoresistive effect element 20 and the permanent magnet 9 exist in the order from the main surface of the substrate 5 to the upper portion of the main surface of the substrate. This is because the magnetic field detection unit that is the magnetoresistive effect element 20 may be affected by the magnetic field of the permanent magnet 9 at the time of manufacture. Therefore, after the magnetic field detection unit that is the magnetoresistive effect element 20 is formed, the permanent magnet 9 is formed. This is because it is preferable to do this.

  Although not shown in FIG. 2, the magnetic field detection part, the permanent magnet 9 and the electrode terminal 3 are separated by an insulating layer, respectively, and electrical short-circuits between each part can be prevented. When the substrate is made of a conductive material, an insulating layer is formed on the main surface of the substrate 5, and an electrical short circuit through the substrate can be prevented. As the insulating layer, for example, inorganic materials such as alumina, aluminum nitride, silicon oxide, and silicon nitride, and organic materials such as polyimide are preferable.

  As illustrated in FIGS. 1 and 2, the permanent magnet 9 is generally a rectangular parallelepiped, and the longitudinal direction thereof is preferably the magnetization direction of the magnetic poles. Thereby, demagnetization of the permanent magnet 9 can be prevented. Moreover, the influence from the other magnetic pole that cancels out the magnetic field generated from one magnetic pole can be suppressed. Further, it is preferable that the longitudinal direction of the free layer and the magnetization direction of the magnetic pole are parallel. As a result, the magnetization direction of the free layer can be stabilized. Incidentally, although FIGS. 1 and 2 exemplify the N pole and the S pole, both poles may be reversed. The permanent magnet 9 is preferably magnetized simultaneously on a multi-sided substrate (not shown) having a plurality of magnetic field detection devices 1 on the substrate 5. In this case, since the magnetization directions of the permanent magnets 9 corresponding to the plurality of magnetic field detection devices 1 are determined at the same time, the bias magnetic field direction as compared with the case where magnetization is performed after the multi-sided substrate (not shown) is separated. Individual differences can be reduced. Note that the order of the simultaneous magnetization is not particularly limited as long as it is before the separation of the multi-sided substrate after the permanent magnet 9 is patterned in the process of manufacturing the magnetic field detection device 1. As a specific magnetization method, a magnetic field for magnetization is applied to the entire surface of the multi-sided substrate at room temperature. The magnetization magnetic field is applied so as to be uniform and in the same direction over the entire surface of the multi-sided substrate. The application direction of the magnetic field for magnetization is preferably parallel to the longitudinal direction of the free layer. That is, the longitudinal direction of the free layer and the magnetization direction of the magnetic pole are preferably parallel.

  As illustrated in FIGS. 1 to 3, the projection surface in the normal direction of the main surface of the substrate 5 of the permanent magnet 9 is the same as the projection surface in the normal direction of the main surface of the substrate 5 of the magnetic field detection unit. It is preferable to arrange so as to include. Thereby, the area of the whole magnetic field detection apparatus 1 can be reduced compared with the case where the permanent magnet 9 is placed on the side of the magnetic field detection unit. If the magnetic field detector is arranged so as not to be included in the projection surface of the permanent magnet 9, the magnetic field of the permanent magnet 9 exerted on the magnetic field detector is not uniform or weak, which is not preferable. That is, the projection surface in the normal direction of the main surface of the substrate 5 of the permanent magnet 9 is the projection surface in the normal direction of the main surface of the substrate 5 of the magnetoresistive element 20 that is a magnetic field detection element included in the magnetic field detection unit. By disposing all of them, the magnetic field generated by the permanent magnet 9 can be efficiently used for the magnetic field detector.

  Furthermore, in this embodiment, it is preferable to arrange the compensation current line 4 illustrated in FIG. The compensation current line 4 has a normal line of the main surface of the substrate 5 as a normal line, and differs from the first to third planes, and is a fourth plane existing between the main surface of the substrate 5 and the third plane. And a compensation current for applying a compensation magnetic field in a direction to cancel the external magnetic field detected by the magnetic field detection unit to the magnetic field detection unit. Note that the direction of the external detection magnetic field detected by the magnetic field detection unit and the bias magnetic field generated by the permanent magnet 9 are generally orthogonal. That is, the magnetic field detection unit detects an external magnetic field that is substantially orthogonal to the longitudinal direction of the magnetoresistive effect element 20 that is the magnetic field detection unit. One end of the compensation current line 4 is connected to the electrode terminal 3 </ b> A by a via that is a part of the internal wiring 2 (not shown) rising in the normal direction of the main surface of the substrate 5. The other end of the compensation current line 4 is connected to the electrode terminal 3B by an internal wiring 2 (not shown). By adopting such a configuration, it is possible to reduce an adverse effect caused by an unexpected change in the resistance of the magnetoresistive effect element due to the environmental temperature or external noise, thereby improving the magnetic field detection accuracy. The compensation current line 4 is made of a conductor such as Cu, and is separated from the magnetoresistive element 20 by an insulating layer (not shown). As the insulating layer, for example, inorganic materials such as alumina, aluminum nitride, silicon oxide, and silicon nitride, and organic materials such as polyimide are preferable.

  Here, in FIG. 1, the permanent magnet 9 does not overlap the electrode terminal 3 when viewed from the normal line of the main surface of the substrate 5, but extends in the X direction of the permanent magnet 9 and overlaps the electrode terminal 3. You may arrange as follows. In this case, since the end of the permanent magnet 9 in the X direction is separated from the magnetoresistive element 20, when the permanent magnet 9 is magnetized in the X direction, the magnetoresistive element 20 is more magnetic field parallel to the X direction. Is provided from the permanent magnet 20, so that the free layer of the magnetoresistive element 20 becomes more stable. Further, the permanent magnet 9 and the electrode terminal 3 may overlap without extending the permanent magnet 9 in the X direction, and the magnetic field detection device 1 can be downsized. For example, by arranging the permanent magnet 9 below the compensation current line 4 (on the substrate 5 side), the permanent magnet 9 and the compensation current line 4 shown in FIG. 4 can be easily seen from the normal line of the main surface of the substrate 5. It becomes possible to have a structure in which the connected electrode terminals (3A, 3B) overlap.

  Although the magnetic field detection unit has been described as being the magnetoresistive element 20, the magnetic field detection unit may be an AMR element having no fixed layer having a magnetization direction fixed in a certain direction. In addition, the magnetic field detection part in this embodiment points out the element which is sensitive to a magnetic field.

  The present invention is applicable to a magnetic field detection device and a device that uses the magnetic field detection device.

DESCRIPTION OF SYMBOLS 1 Magnetic field detector 2 Internal wiring 3 Electrode terminal 4 Compensation current line 5 Substrate 9 Permanent magnet 20 Magnetoresistive element

Claims (9)

A substrate,
A magnetic field detector disposed on a first plane spaced apart from the substrate on the main surface of the substrate having a normal to the main surface of the substrate;
A permanent magnet having a magnetization direction disposed on a second plane spaced from the substrate on the main surface of the substrate, the normal line being different from the first plane and having a normal to the main surface of the substrate as a normal line;
Unlike the first and second planes, the normal on the main surface of the substrate having a normal to the main surface of the substrate that is further away from the main surface of the substrate than the first and second planes. An electrode terminal disposed on a third plane separated from the substrate and connected to the magnetic field detector;
An internal wiring connected to the electrode terminal and the magnetic field detector;
The magnetic field detection apparatus in which the magnetic field detection unit, the permanent magnet, the electrode terminal, and the internal wiring are integrally formed on the main surface of the substrate.   The magnetic field detection device according to claim 1, wherein the magnetic field detection unit, the permanent magnet, and the terminal electrode are separated by an insulating layer.   The magnetic field detection device according to claim 1, wherein an insulating layer is formed on a main surface of the substrate.   4. The magnetic field detection device according to claim 1, wherein the permanent magnet is substantially a rectangular parallelepiped, and a longitudinal direction thereof is the magnetization direction of the magnetic pole. 5.   5. The magnetic field detection device according to claim 1, wherein the projection surface of the permanent magnet in the normal direction of the main surface of the substrate includes all the projection surfaces of the magnetic field detection unit in the normal direction. .   Different from the first to third planes, the normal line of the main surface of the substrate is a normal line, and is arranged on a fourth plane existing between the main surface of the substrate and the third plane. The magnetic field according to any one of claims 1 to 5, further comprising a compensation current line through which a compensation current for applying a compensation magnetic field in a direction for canceling an external magnetic field detected by the magnetic field detection unit to the magnetic field detection unit. Detection device.   The magnetic field detection device according to claim 6, wherein the permanent magnet and an electrode terminal connected to the compensation current line extending in a longitudinal direction of the permanent magnet have an overlap as viewed from a normal line of the main surface of the substrate. .   A multi-sided substrate in which a plurality of the magnetic field detection devices according to claim 1 are present on the main surface of the substrate.   9. A magnetic field detection apparatus in which the magnetization direction is determined by applying a magnetization magnetic field to the multi-sided substrate according to claim 8.

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