Magnetic sensor element

Abstract

To provide a magnetic sensor element that can improve the output while being prevented from becoming large in size.SOLUTION: A magnetic sensor element 1 includes: a substrate 2; an elongated magnetic core 3 disposed on the substrate 2; and a coil 4 made of a thin-film conductor spirally arranged around the outer circumference of the magnetic core 3. The coil 4 includes: a first coil part 41, which is wound around the outer circumference of the magnetic core 3 with a first insulating layer 51 in between; and a second coil part 42, which is wound around the outer circumference of the first coil part 41 with a second insulating layer 52 in between. At least one of the first coil part 41 and the second coil part 42 is a detection coil part in which a voltage is induced according to the magnitude of a magnetic field to be detected.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a magnetic sensor element. [Background technology]

[0002] As a magnetic sensor element, a magneto-impedance element including a substrate, a magnetic wire disposed on the substrate, and a detection coil made of a thin film conductor wound in a spiral shape around the magnetic wire is disclosed in Patent Document 1. For such a magnetic sensor element, there is a demand for a higher output depending on the application. In order to improve the sensor output, it is considered to increase the number of turns of the detection coil. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 3781056 Summary of the Invention [Problem to be solved by the invention]

[0004] However, simply increasing the number of turns of the detection coil leads to an increase in the size of the magnetic sensor element. Therefore, it is possible to consider making the winding pitch of the detection coil finer. However, there are limitations in terms of manufacturing and performance to making the detection coil finer.

[0005] The present invention has been made in view of the above problems, and aims to provide a magnetic sensor element that can improve output while suppressing an increase in size. [Means for solving the problem]

[0006] One aspect of the present invention is a magnetic sensor element including a substrate, a long magnetic core disposed on the substrate, and a coil made of a thin film conductor spirally disposed around an outer periphery of the magnetic core, The coil has at least a first coil portion wound around an outer periphery of the magnetic core with a first insulating layer interposed therebetween, and a second coil portion wound around an outer periphery of the first coil portion with a second insulating layer interposed therebetween, At least one of the first coil portion and the second coil portion is in a magnetic sensor element, which is a detection coil portion in which a voltage corresponding to the magnitude of a magnetic field to be detected is induced. Effect of the Invention

[0007] In the magnetic sensor element, the coil has at least a first coil portion wound around the outer periphery of the magnetic core with a first insulating layer interposed therebetween, and a second coil portion wound around the outer periphery of the first coil portion with a second insulating layer interposed therebetween. This makes it possible to increase the number of turns of the coil while suppressing an increase in the size of the magnetic core in the longitudinal direction, even without making the coil finer-pitch. As a result, it is possible to improve the output of the magnetic sensor element while suppressing an increase in the size.

[0008] As described above, according to the above aspect, it is possible to provide a magnetic sensor element that can improve output while suppressing an increase in size. [Brief description of the drawings]

[0009] [Figure 1] FIG. 2 is a plan view of the magnetic sensor element according to the first embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II in FIG. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2 . [Figure 4] 5A to 5C are explanatory views of a method for manufacturing the magnetic sensor element according to the first embodiment. [Diagram 5] FIG. 11 is a plan view of a magnetic sensor element according to a second embodiment. [Figure 6] 11A is an explanatory diagram of a first coil section, and FIG. 11B is an explanatory diagram of a second coil section in a second embodiment. [Figure 7] FIG. 6 is a cross-sectional view taken along line DD in FIG. 5 . [Figure 8] 6 is a cross-sectional view taken along line AA in FIG. 5. [Figure 9] FIG. 6 is a cross-sectional view taken along line BB in FIG. 5 . [Figure 10] 6 is a cross-sectional view taken along line CC in FIG. 5 . [Figure 11] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment at the stage when the second lower wiring portion and the like are formed. [Figure 12] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment, at the stage where a lower layer of the second insulating layer and the like have been formed. [Figure 13] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment at the stage when a first lower wiring portion and the like are formed. [Figure 14] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment, at the stage where a layer below the first insulating layer and the like have been formed. [Figure 15] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment at the stage when a wire fixing portion and the like have been formed. [Figure 16] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment, at the stage where an upper layer of the first insulating layer and the like have been formed. [Figure 17] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment at the stage when a first upper wiring portion and the like are formed. [Figure 18] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment, showing the stage where an upper layer of the second insulating layer and the like have been formed. [Figure 19] FIG. 11 is an explanatory diagram of the method for manufacturing the magnetic sensor element according to the second embodiment at the stage when the second upper wiring portion and the like are formed. [Figure 20] FIG. 11 is a plan view of a magnetic sensor element according to a third embodiment. [Figure 21] FIG. 11 is a plan view of a first coil portion in the third embodiment. [Figure 22] 4 is a microscope photograph of the appearance of a part of the magnetic sensor element in Experimental Example 1. [Figure 23] 4 is a cross-sectional microscope photograph of a portion of the magnetic sensor element in Experimental Example 1. [Figure 24] 4 is a diagram showing the measurement results of output characteristics in Experimental Example 1. [Diagram 25] FIG. 11 is a plan view of a magnetic sensor element according to a fourth embodiment. [Figure 26] 26 is a cross-sectional view taken along line XXVI-XXVI in FIG. 25. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The magnetic sensor element may be a magneto-impedance element (hereinafter, also referred to as an MI element) that utilizes the magnetic impedance effect. However, the magnetic sensor element may be, for example, an electromagnetic induction type fluxgate sensor element, a magnetic flux response type magnetic flux sensor element, or the like, other than the MI element.

[0011] In addition, both the first coil section and the second coil section may be the detection coil section, the first coil section and the second coil section may be connected in series to each other, and the first coil section and the second coil section may have the same winding direction. In this case, it is possible to improve the output while suppressing the increase in size.

[0012] The magnetic core may be made of a magnetic wire, the first coil section may have a plurality of split coil sections connected in series with each other, a wire fixing section for fixing the magnetic wire to the substrate may be provided in an intermittent section between the split coil sections, and a part of the second coil section may be wound around the outer periphery of the intermittent section. In this case, the magnetic wire may be easily and accurately positioned at a predetermined position, and a high-output magnetic sensor element may be obtained. That is, by providing the wire fixing section at a predetermined position, the magnetic wire may be easily and accurately positioned at a predetermined position. However, when the wire fixing section is provided, it becomes difficult to wind the first coil section around the magnetic wire at that location. Therefore, an intermittent section is provided, and a wire fixing section is provided in the intermittent section. The second coil section has a relatively large winding radius, so that it is easy to wind around the outer periphery of the wire fixing section, and is also wound around the outer periphery of the intermittent section. This allows the number of turns of the coil to be increased as a whole, and the output to be improved.

[0013] The second coil portion may be wound in a uniform spiral shape from one end to the other end in the longitudinal direction of the magnetic wire, thereby further improving the output of the magnetic sensor element.

[0014] (Embodiment 1) An embodiment of the magnetic sensor element will be described with reference to FIGS. 1 to 3, the magnetic sensor element 1 of this embodiment includes a substrate 2, a magnetic wire 3 as a magnetic core, and a coil (a detection coil 4 in this embodiment). The magnetic wire 3 is disposed on the substrate 2. The detection coil 4 is made of a thin film conductor provided in a spiral shape around the outer periphery of the magnetic wire 3.

[0015] The detection coil 4 has at least a first coil portion 41 and a second coil portion 42. The first coil portion 41 is wound around the outer periphery of the magnetic wire 3 with a first insulating layer 51 interposed therebetween. The second coil portion 42 is wound around the outer periphery of the first coil portion 41 with a second insulating layer 52 interposed therebetween. The first coil portion 41 and the second coil portion 42 are connected in series with each other. The first coil portion 41 and the second coil portion 42 have the same winding direction.

[0016] Here, the same winding direction means that when the coil wiring of the detection coil 4 is traced from one end to the other end, the circumferential direction around the magnetic wire 3 is the same. For convenience, the first insulating layer 51 and the second insulating layer 52 are omitted in FIG. 1.

[0017] In this embodiment, both the first coil section 41 and the second coil section 42 are detection coil sections in which a voltage corresponding to the magnitude of the magnetic field to be detected is induced. When a pulse current or a high-frequency current is applied to the magnetic wire 3, a voltage corresponding to the magnitude of the magnetic field to be detected is induced in the detection coil 4 in which the first coil section 41 and the second coil section 42 are connected in series.

[0018] In this embodiment, the magnetic sensor element 1 is an MI element. The substrate 2 is a non-magnetic flat substrate, and may be, for example, a ceramic substrate such as an alumina substrate, or a semiconductor wafer such as silicon.

[0019] The magnetic wire 3 is an amorphous wire, and may be a wire having a substantially circular cross section perpendicular to the longitudinal direction. The diameter of the magnetic wire 3 may be, for example, 1 to 50 μm. Hereinafter, the longitudinal direction of the magnetic wire 3 is appropriately referred to as the X direction. The normal direction of the substrate 2 is appropriately referred to as the Z direction. The direction perpendicular to both the Z direction and the X direction is appropriately referred to as the Y direction.

[0020] The detection coil 4 is made of a thin film conductor having a thickness of, for example, about 1 to 10 μm. As shown in Fig. 1 and Fig. 2, the first coil section 41 is composed of a plurality of first lower wiring sections 411 formed on the lower side of the magnetic wire 3 and a plurality of first upper wiring sections 412 connected to the first lower wiring sections 411. The second coil section 42 is composed of a plurality of second lower wiring sections 421 formed on the substrate 2 and a plurality of second upper wiring sections 422 connected to the second lower wiring sections 421.

[0021] 1, the first coil portion 41 and the second coil portion 42 constituting the detection coil 4 are connected to each other at one end in the X direction. That is, a connection portion 46 that connects the first coil portion 41 and the second coil portion 42 to each other is provided at one end of the first coil portion 41 and the second coil portion 42. In this embodiment, the other end portions in the X direction of the first coil portion 41 and the second coil portion 42 are not connected to each other. The other end portions in the X direction of the first coil portion 41 and the second coil portion 42 are connected to coil terminals (not shown).

[0022] Although not shown, both ends of the magnetic wire 3 are fixed to the substrate 2 and connected to terminals. The first insulating layer 51 and the second insulating layer 52 are made of a resin material such as a phenol resin.

[0023] An example of a method for manufacturing the magnetic sensor element 1 of this embodiment will be outlined with reference to FIG. 4, the second lower wiring portion 421, a part (lower layer) of the second insulating layer 52, the first lower wiring portion 411, and a part (lower layer) of the first insulating layer 51 are sequentially formed on the upper surface of the substrate 2, and the magnetic wire 3 is disposed on the part (lower layer) of the first insulating layer 51. The formation of each wiring portion and each insulating layer can be performed using photolithography. The same applies to the formation of the wiring portion and insulating layer described later.

[0024] Next, another part (upper layer) of the first insulating layer 51 is formed so as to cover the magnetic wire 3 (step S2). This results in a state in which the magnetic wire 3 is embedded in the first insulating layer 51.

[0025] Next, a plurality of first upper wiring portions 412 are formed on the surface (top and side surfaces) of the first insulating layer 51 (step S3). The first upper wiring portions 412 are connected to the first lower wiring portions 411 at both ends in the Y direction. Each first upper wiring portion 412 is formed so as to connect the first lower wiring portions 411 adjacent to each other in the X direction (see FIG. 1). As a result, a spiral first coil portion 41 is formed on the outer periphery of the magnetic wire 3.

[0026] Next, another part (upper layer) of the second insulating layer 52 is formed so as to cover the first coil portion 41 (step S4).

[0027] Next, a plurality of second upper wiring portions 422 are formed on the surface (top and side surfaces) of the second insulating layer 52 (step S5). The second upper wiring portions 422 are connected to the second lower wiring portions 421 at both ends in the Y direction. Each second upper wiring portion 422 is formed so as to connect the second lower wiring portions 421 adjacent to each other in the X direction (see FIG. 1). As a result, a spiral second coil portion 42 is formed on the outer periphery of the magnetic wire 3.

[0028] In any one of steps S1, S3, and S5 described above, the first coil portion 41 and the second coil portion 42 are connected to each other at one end in the X direction. As a result, in the stage of step S5, the detection coil 4 in which the first coil portion 41 and the second coil portion 42 are connected in series is formed. In this manner, the magnetic sensor element 1 can be obtained.

[0029] Next, the effects of this embodiment will be described. In the magnetic sensor element 1, the detection coil 4 has at least a first coil portion 41 wound around the outer periphery of the magnetic wire 3 with a first insulating layer 51 interposed therebetween, and a second coil portion 42 wound around the outer periphery of the first coil portion 41 with a second insulating layer 52 interposed therebetween. This makes it possible to increase the number of turns of the detection coil 4 while suppressing an increase in the size of the magnetic wire 3 in the longitudinal direction (X direction) without particularly making the detection coil 4 finer pitch. As a result, it is possible to improve the output of the magnetic sensor element 1 while suppressing an increase in size.

[0030] As described above, when the detection coil 4 made of a thin film conductor is formed so as to surround the magnetic wire 3, the thin film conductor is formed at different positions in the Z direction. Therefore, fine pitching of the coil tends to make the patterning of the coil (patterning of the thin film conductor) difficult. From this perspective, by forming the detection coil 4 into a multiple structure of the first coil portion 41 and the second coil portion 42 as in this embodiment, fine pitching can be suppressed, and manufacturing becomes easier. Furthermore, since fine pitch can be suppressed, it is possible to secure a certain degree of line width of the detection coil 4. As a result, it is advantageous in that the electrical resistance of the detection coil 4 can also be reduced.

[0031] As described above, according to the present embodiment, it is possible to provide a magnetic sensor element that can improve output while suppressing an increase in size.

[0032] (Embodiment 2) As shown in Figs. 5 to 10, this embodiment is a magnetic sensor element 1 in which a first coil portion 41 has a plurality of split coil portions 44 connected in series to each other. In this embodiment, a wire fixing portion 12 that fixes the magnetic wire 3 to the substrate 2 is provided in the gap 45 between the split coil portions 44. A part of the second coil portion 42 is wound around the outer periphery of the gap 45.

[0033] In this embodiment, as shown in Fig. 6(a), the first coil portion 41 has two split coil portions 44. The two split coil portions 44 are connected in series to each other via the second coil portion 42 as shown in Fig. 5. Fig. 6(a) is a schematic plan view showing the magnetic wire 3, the first coil portion 41, and the wire fixing portions 12, 120, with other configurations omitted. Fig. 6(b) is a schematic plan view showing the magnetic wire 3, the second coil portion 42, and the wire fixing portions 12, 120, with other configurations omitted.

[0034] As shown in Fig. 6(a), the first coil portion 41 has an intermittent portion 45 in approximately the center in the X direction. Two split coil portions 44 are arranged on opposite sides of the intermittent portion 45 in the X direction. As shown in Fig. 5, the end of each split coil portion 44 on the intermittent portion 45 side is connected to a coil terminal 111. Also, each split coil portion 44 has an end on the opposite side in the X direction to the intermittent portion 45 connected to the second coil portion 42. That is, both ends of the first coil portion 41 and both ends of the second coil portion 42 form connection portions 46 between the two.

[0035] Due to the manner in which the first coil portion 41 and the second coil portion 42 are connected in this manner, the coil wiring of the detection coil 4 is configured so that, when traced from one end to the other, the circumferential direction around the magnetic wire 3 is the same. That is, the coil wiring of the detection coil 4 is wound so that the winding directions of the first coil portion 41 and the second coil portion 42 are the same. When a current flows through the detection coil 4, the current flows in the first coil portion 41 and the second coil portion 42 in the same direction, either clockwise or counterclockwise, when viewed in a cross section perpendicular to the X direction (see FIG. 9).

[0036] 5 and 6(b), the second coil portion 42 is uniformly wound in a spiral shape from one end to the other end in the X direction. That is, unlike the first coil portion 41, the second coil portion 42 is formed uniformly without being divided in the X direction.

[0037] 5 to 7, the wire fixing portion 12 is disposed in the intermittent portion 45. That is, the magnetic wire 3 is fixed to the substrate 2 at the intermittent portion 45. The magnetic wire 3 is also fixed to the substrate 2 near both ends in the X direction by wire fixing portions 120. The wire fixing portions 120 are disposed at positions outside the detection coil 4 in the X direction.

[0038] The magnetic wire 3 is connected to wire connection terminals 113 at both ends in the X direction. The wire connection terminal 113 is electrically connected to a wire terminal 112 which is electrically connected to the outside. A wire fixing portion 120 is disposed inside the wire connection terminal 113 in the X direction. The wire connection terminal 113 is made of a conductor such as copper.

[0039] 8, the wire connection terminal 113 is formed so as to cover the end of the magnetic wire 3 from the outer periphery. A wire fixing part 120 fixed to the substrate 2 at a position adjacent to the wire connection terminal 113 has a pair of guide parts 121 standing on both sides in the Y direction, and a connecting part 122 connecting the guide parts 121 at their protruding ends. The pair of guide parts 121 position and fix the magnetic wire 3 in the Y direction. The connecting part 122 positions and fixes the magnetic wire 3 in the Z direction. The wire fixing part 120 is made of a resin such as epoxy.

[0040] 9 shows the cross-sectional structure of the magnetic sensor element 1 in a region where the split coil portion 44 of the first coil portion 41 is arranged (cross section BB in FIG. 5). This layer structure is substantially similar to that shown in the first embodiment (see FIG. 2). Note that the upper wiring portions of the first coil portion 41 and the second coil portion 42, etc., are substantially curved.

[0041] 10, the wire fixing portion 12 provided in the intermittent portion 45 has substantially the same configuration as the wire fixing portions 120 (see FIG. 8) near both ends of the magnetic wire 3. The guide portion 121 is fixed to the substrate 2 via a second insulating layer 52. Also, as shown in FIG. 10, the first coil portion 41 is not provided in the intermittent portion 45, but the second coil portion 42 is provided.

[0042] Next, an example of a manufacturing method of the magnetic sensor element 1 of this embodiment will be described with reference to Fig. 11 to Fig. 19. Fig. 11 to Fig. 19 are schematic plan views of the workpiece in each process, and their AA, BB, and CC cross-sectional views, respectively. Note that the wire terminals 112 and coil terminals 111, etc. are omitted in each cross-sectional view.

[0043] 11, a plurality of second lower wiring portions 421 are formed on the substrate 2. The plurality of second lower wiring portions 421 are formed at approximately equal intervals. In addition, a part (lower layer portion) of the wire connection terminal 113, the wire terminal 112, and a connection wiring that connects these are formed on the substrate 2. These wirings and the like are formed by pattern formation of metal plating or the like using photolithography.

[0044] 12, a part (lower layer) of the second insulating layer 52 is formed so as to cover a part of the second lower wiring portion 421. That is, the lower layer of the second insulating layer 52 is formed on the substrate 2 from above the second lower wiring portion 421 while exposing both ends of the second lower wiring portion 421 in the Y direction.

[0045] 13, a plurality of first lower wiring portions 411 are formed on the second insulating layer 52. Note that the first lower wiring portions 411 are not provided in the locations that will become the intermittent portions 45. In addition, the coil terminals 111 and the connection wiring extending from the coil terminals 111 are formed on the substrate 2.

[0046] 14, a part (lower layer) of the first insulating layer 51 is formed from above the first lower wiring portion 411. The lower layer of the first insulating layer 51 is formed while exposing both ends in the Y direction of the first lower wiring portion 411. In addition, a guide portion 121, which is a part of the wire fixing portions 12, 120, is provided at a predetermined position on the lower layer of the first insulating layer 51.

[0047] Next, as shown in Fig. 15, the magnetic wire 3 is placed on the lower layer of the first insulating layer 51. At this time, the magnetic wire 3 is fitted between pairs of guide parts 121 at three points in the X direction. This determines the position of the magnetic wire 3 in the Y direction. Thereafter, the connecting parts 122 are disposed on the three pairs of guide parts 121 and fixed. As a result, the magnetic wire 3 is fixed to the substrate 2 by the wire fixing parts 12, 120 at three points.

[0048] 16, an upper layer of the first insulating layer 51 is formed on the lower layer of the first insulating layer 51 so as to cover the magnetic wire 3. This results in the magnetic wire 3 being embedded in the first insulating layer 51 except for both ends. Also, an upper layer of the wire connecting terminal 113 is provided on the lower layer of the wire connecting terminal 113 so as to cover both ends of the magnetic wire 3. This results in both ends of the magnetic wire 3 being embedded in the wire connecting terminal 113. The wire fixing portion 12 near the center of the magnetic wire 3 may be exposed from the first insulating layer 51.

[0049] 17, a plurality of first upper wiring portions 412 are formed on the surface of the first insulating layer 51. The first upper wiring portions 412 are not provided in the locations that will become the intermittent portions 45. The first upper wiring portions 412 are connected to the already formed first lower wiring portions 411 to form the first coil portion 41. As a result, two split coil portions 44 are formed on opposite sides of the intermittent portion 45, which form the first coil portion 41.

[0050] 18, an upper layer of the second insulating layer 52 is provided so as to cover the first coil portion 41 and the wire fixing portion 12. As a result, the first coil portion 41 and the wire fixing portion 12 are embedded in the second insulating layer 52.

[0051] 19, a plurality of second upper wiring portions 422 are formed on the surface of the second insulating layer 52. The plurality of second upper wiring portions 422 are formed at substantially uniform intervals. The plurality of second upper wiring portions 422 are connected to the plurality of second lower wiring portions 421 that have already been formed to form the second coil portion 42. In this manner, the magnetic sensor element 1 of the present embodiment is obtained.

[0052] The rest is the same as in embodiment 1. Note that, among the symbols used in embodiment 2 and onwards, the same symbols used in the previous embodiments represent the same components, etc. as in the previous embodiments, unless otherwise specified.

[0053] In this embodiment, the magnetic wire 3 can be easily and accurately arranged at a predetermined position, and a high-output magnetic sensor element 1 can be obtained. That is, by providing the wire fixing portion 12 at a predetermined position, the magnetic wire 3 can be easily and accurately arranged at a predetermined position. However, when the wire fixing portion 12 is provided, it becomes difficult to wind the first coil portion 41 around the magnetic wire 3 at that location. Therefore, an intermittent portion 45 is provided, and the wire fixing portion 12 is provided at the intermittent portion 45. Since the second coil portion 42 has a relatively large winding radius, it is easy to wind it around the outer periphery of the wire fixing portion 12, and it is also wound around the outer periphery of the intermittent portion 45. As a result, the number of turns of the detection coil 4 can be increased as a whole, and the output can be improved.

[0054] Moreover, the second coil portion 42 is uniformly wound in a spiral shape from one end to the other end in the X direction. This makes it possible to efficiently increase the number of turns of the detection coil 4, and further improve the output of the magnetic sensor element 1. In addition, the same effects as those of the first embodiment are achieved.

[0055] (Embodiment 3) In this embodiment, as shown in FIGS. 20 and 21, the first coil portion 41 is provided with ten split coil portions 44. In the embodiment shown in FIG. Of the ten split coil portions 44, five of each are connected in series by direct connection wiring, and the split coil portions 44 at both ends in the X direction are connected in series via the second coil portion 42.

[0056] In this embodiment, the first coil portion 41 has nine intermittent portions 45. A wire-fixing portion 12 is provided in each intermittent portion 45. Further, wire-fixing portions 120 are provided near both ends of the magnetic wire 3. The rest is the same as in the second embodiment.

[0057] In the magnetic sensor element 1 of this embodiment, the magnetic wire 3 is made long and the number of turns of the detection coil 4 is increased, thereby making it possible to increase the output. In addition, the same effects as those of the second embodiment are achieved.

[0058] (Experimental Example 1) This example is an example in which the sensitivity of the magnetic sensor element 1 and the electric resistance of the detection coil 4 of the third embodiment are evaluated. FIG. 22 shows a plan view of a part of the magnetic sensor element 1 (hereinafter, referred to as sample 1) according to the third embodiment used for the evaluation, and FIG. 23 shows a cross-sectional view of the part.

[0059] In sample 1, the diameter of the magnetic wire 3 is 25 μm, the distance from the center of the magnetic wire 3 to the first coil portion 41 in the Z direction is 14.5 μm, the distance from the center of the magnetic wire 3 to the first coil portion 41 in the Y direction is 33.5 μm, the distance from the center of the magnetic wire 3 to the second coil portion 42 in the Z direction is 21.5 μm, and the distance from the center of the magnetic wire 3 to the second coil portion 42 in the Y direction is 86 μm.

[0060] The length of the magnetic wire 3 in the X direction is 6 mm. The thickness of the thin film conductor of the detection coil 4 is 5.0 μm. Except for the intermittent portion 45, the wiring pitch of the detection coil 4 is 30 μm, and the line and space is 15 μm / 15 μm by design. The total number of turns of the detection coil 4 is 330.

[0061] For comparison, a magnetic sensor element in which the detection coil is not a multiple structure but is formed in a single spiral shape was prepared as sample 2. The detection coil in sample 2 has substantially the same shape and dimensions as the first coil section 41 in sample 1 (see FIG. 21). However, the detection coil in sample 2 differs from the first coil section 41 in sample 1 in that coil terminals are drawn out from both ends in the X direction. The wiring pitch of the detection coil is 15 μm, and the line and space is 7.5 μm / 7.5 μm by design. The total number of turns of the detection coil in sample 2 is 330, the same as sample 1.

[0062] A magnetic field was applied to Sample 1 and Sample 2 while gradually changing the magnetic field in the sensitivity direction (X direction) between -2 G and +2 G. The output voltage characteristics obtained at this time are shown in FIG. 24. The sensitivity of each sample derived from the results shown in the figure is shown in Table 1 with specific numerical values. In addition, the DC resistance of the detection coil of each sample was measured using a multimeter. The results are also shown in Table 1.

[0063] [Table 1]

[0064] As can be seen from FIG. 24 and Table 1, Sample 1 has a higher output voltage and higher sensitivity than Sample 2. Specifically, as shown in Table 1, Sample 2 has a sensitivity of 2.06 V / G, while Sample 1 has a high sensitivity of 2.44 V / G. In addition, the electrical resistance of the detection coil of Sample 1 is reduced to nearly half that of Sample 2.

[0065] (Embodiment 4) As shown in Figs. 25 and 26, this embodiment is a magnetic sensor element 1 in which the detection coil 4 has a triple structure.

[0066] That is, in the magnetic sensor element 1 of this embodiment, the detection coil 4 further includes a third coil portion 43 in addition to the first coil portion 41 and the second coil portion 42. The third coil portion 43 is wound around the outer periphery of the second coil portion 42 with a third insulating layer 53 interposed therebetween. The third insulating layer 53 and the third coil portion 43 can be formed by a method similar to the method for forming the first insulating layer 51, the second insulating layer 52, the first coil portion 41, and the second coil portion 42 shown in the second embodiment. The third coil portion 43 is also made of a thin film conductor, like the first coil portion 41 and the second coil portion 42.

[0067] In this embodiment, the first coil portion 41 includes two split coil portions 44, as in the second embodiment. The two split coil portions 44 are connected in series via the second coil portion 42 and the third coil portion 43. One end of the third coil portion 43 (the left end in FIG. 24) and one end of the first coil portion 41 (the right end in FIG. 24) are connected by a connection wiring 47. In the first coil portion 41, wiring is drawn out from the ends of the two split coil portions 44 that are closer to each other and connected to the coil terminals 111, respectively.

[0068] In this embodiment, the current path from one coil terminal 111 to the other coil terminal 111 via the detection coil 4 is, for example, in the following order. That is, the current flows in the order of one (left side in FIG. 24) coil terminal 111, one (left side in FIG. 24) split coil portion 44 of the first coil portion 41, the second coil portion 42, the third coil portion 43, the connection wiring 47, the other (right side in FIG. 24) split coil portion 44 of the first coil portion 41, and the other (left side in FIG. 24) coil terminal 111. The current may flow in the reverse order. In either case, the current flowing through the detection coil 4 has the same circumferential direction around the magnetic wire 3. That is, when a current flows through the detection coil 4, the current direction in the first coil portion 41, the second coil portion 42, and the third coil portion 43 is the same, clockwise or counterclockwise, as viewed in the cross section of FIG. 26.

[0069] The rest is the same as in the second embodiment. The magnetic sensor element 1 of this embodiment can further increase the number of turns of the detection coil 4, thereby increasing the output. In addition, the magnetic sensor element 1 of this embodiment has the same functions and effects as the second embodiment.

[0070] In the third embodiment, the detection coil 4 has a triple-layer structure, but the detection coil 4 may have a four or more layer structure. That is, the detection coil 4 of the magnetic sensor element of the present disclosure has at least a first coil portion 41 and a second coil portion 42.

[0071] In the above embodiment, an example was shown in which all of the multiple coil sections were detection coil sections, but some of the coil sections may be other than detection coil sections. For example, some of the coil sections may be feedback coils that negatively feed back the output of the magnetic sensor element, or bias coils that apply a bias magnetic field to the magnetic sensor element, or may be other coil sections. In these cases, the multiple coil sections may be independent coil sections without being connected in series with each other.

[0072] In the above embodiment, the magnetic core is a bulk magnetic wire, but the magnetic core may be a thin magnetic layer. In this case, there is no need to provide a wire fixing portion (see embodiment 2, etc.).

[0073] The present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist of the present invention. [Explanation of symbols]

[0074] 1. Magnetic sensor element 2. Board 3 Magnetic wire (magnetic core) 4 Detection coil 41 First coil section 42 Second coil section

Claims

1. A magnetic sensor element comprising: a substrate; a long magnetic core disposed on the substrate; and a coil made of a thin film conductor spirally disposed around the outer periphery of the magnetic core, The coil has at least a first coil portion wound around an outer periphery of the magnetic core with a first insulating layer interposed therebetween, and a second coil portion wound around an outer periphery of the first coil portion with a second insulating layer interposed therebetween, At least one of the first coil portion and the second coil portion is a detection coil portion in which a voltage corresponding to the magnitude of a magnetic field to be detected is induced.

2. 2. The magnetic sensor element of claim 1, wherein both the first coil portion and the second coil portion are the detection coil portion, the first coil portion and the second coil portion are connected in series to each other, and the first coil portion and the second coil portion have the same winding direction.

3. 3. The magnetic sensor element of claim 1, wherein the magnetic core is made of a magnetic wire, the first coil portion has a plurality of split coil portions connected in series with each other, a wire fixing portion is provided in the intermittent portion between the split coil portions to fix the magnetic wire to the substrate, and a portion of the second coil portion is wound around the outer periphery of the intermittent portion.

4. The magnetic sensor element according to claim 3 , wherein the second coil portion is wound uniformly in a spiral shape from one end to the other end in the longitudinal direction of the magnetic wire.

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