Magnetic sensor element and manufacturing method of the same

Abstract

To provide a magnetic sensor element less likely to generate noise, and a manufacturing method of the same.SOLUTION: A magnetic sensor element 1 comprises: a substrate 2; a magnetic wire 3 on the substrate 2; and a detection coil 4 composed of a thin film conductor spirally provided on an outer periphery of the magnetic wire 3. A groove part 23 having a recessed internal surface is formed in the substrate 2. The detection coil 4 comprises: a plurality of first wiring parts 41 deposited in parallel to each other on the internal surface of the groove part 23; and a plurality of second wiring parts 42 connected to the first wiring part 41 and formed in parallel to each other. The magnetic wire 3 is arranged in the groove part 23 in which the plurality of first wiring parts 41 are formed, whilst being coated with an insulator 5. The second wiring part 42 is formed via the insulator 5 in a portion of the magnetic wire 3 exposed from the groove part 23. The first wiring part 41 is smoothly connected to the second wiring part 42.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a magnetic sensor element and a manufacturing method thereof. [Background technology]

[0002] Patent Document 1 discloses a magneto-impedance element as a magnetic sensor element, which includes a substrate, a magnetic wire disposed on the substrate, and a detection coil made of a thin-film conductor spirally disposed around the magnetic wire.

[0003] In Patent Document 1, a groove is provided in a substrate, and a thin-film conductor pattern is formed on the bottom and side surfaces of the groove, and a thin-film conductor pattern is also formed on the surface of an insulating layer (hereinafter also referred to as a buried insulating layer) that fills the groove and has a magnetic wire buried in it. These conductor patterns are connected to form a detection coil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 3781056 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the conventional magnetic sensor element has the following problems. That is, edges are formed in the conductor wiring of the detection coil at the corners between the bottom and side surfaces of the groove. Furthermore, edges are also formed at the joints between the conductor wiring formed on the side surfaces of the groove and the conductor wiring formed on the surface of the buried insulating layer. These edges of the detection coil may become noise sources and cause losses in the output characteristics.

[0006] The present invention has been made in view of the above problems, and aims to provide a magnetic sensor element that is less susceptible to noise and a manufacturing method thereof. [Means for solving the problem]

[0007] One aspect of the present invention is a magnetic sensor element including a substrate, a magnetic wire disposed on the substrate, and a detection coil made of a thin film conductor spirally disposed around the magnetic wire, The substrate has a groove having a concave inner wall surface, the detection coil has a plurality of first wiring portions formed in parallel to one another on an inner wall surface of the groove portion, and a plurality of second wiring portions connected to the first wiring portions and formed in parallel to one another, the magnetic wire is covered with an insulator and disposed in the groove in which the first wiring portions are formed, the second wiring portion is formed on a portion of the magnetic wire exposed from the groove portion via the insulator, The first wiring portion and the second wiring portion are smoothly connected to each other in the magnetic sensor element.

[0008] Another aspect of the present invention is a method for manufacturing the magnetic sensor element, comprising the steps of: forming the groove portion on the surface of the substrate; a plurality of the first wiring portions are formed on an inner wall surface of the groove, and then the magnetic wire is disposed in the groove via a part of the insulator; The method for manufacturing a magnetic sensor element further includes forming a plurality of the second wiring portions on the portion of the magnetic wire exposed from the groove portion, via another part of the insulator. Effect of the Invention

[0009] In the magnetic sensor element, a groove having a concavely curved inner wall surface is formed in the substrate. Therefore, it is possible to prevent edges from being formed in the first wiring portion formed in the inner wall surface of the groove. In addition, the first wiring portion and the second wiring portion are smoothly connected. This makes it possible to prevent edges from being formed in the joint between the first wiring portion and the second wiring portion. As a result, it is possible to prevent edges from being formed in the detection coil, and to suppress the generation of noise.

[0010] As described above, according to the above aspect, it is possible to provide a magnetic sensor element that is less susceptible to noise and a method for manufacturing the same. [Brief description of the drawings]

[0011] [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. 4 is a plan view of the magnetic sensor element from which the magnetic wire and the second wiring portion have been removed in the first embodiment. [Figure 4] 5A to 5C are explanatory views of a method for manufacturing the magnetic sensor element according to the first embodiment. [Diagram 5] 5 is an explanatory diagram of the manufacturing method of the magnetic sensor element according to the first embodiment, following FIG. 4. [Figure 6] FIG. 4 is an explanatory diagram of a method for forming a groove portion in the first embodiment. [Figure 7] FIG. 11 is a cross-sectional view illustrating a magnetic sensor element according to a comparative example. [Figure 8] 8A to 8C are explanatory views of a method for manufacturing a magnetic sensor element according to the second embodiment. [Figure 9] 9 is an explanatory diagram of the manufacturing method of the magnetic sensor element according to the second embodiment, following FIG. 8. [Figure 10] 10A to 10C are explanatory views of a method for manufacturing a magnetic sensor element according to a third embodiment. [Figure 11] 10A to 10C are explanatory views of a method for manufacturing a magnetic sensor element according to a fourth embodiment. [Figure 12]FIG. 13 is a plan view of a magnetic sensor element according to a fifth embodiment. [Figure 13] FIG. 2 is a cross-sectional view taken along line XXII-XXII in FIG. [Figure 14] 13A to 13C are explanatory views of a method for manufacturing a magnetic sensor element according to a fifth embodiment. [Figure 15] 14A to 14C are explanatory views of the method for manufacturing the magnetic sensor element according to the fifth embodiment. [Figure 16] FIG. 23 is an explanatory cross-sectional view showing a state in which a magnetic wire 3 is arranged after a first insulator 51 is formed in the sixth embodiment. [Figure 17] FIG. 13 is an explanatory cross-sectional view showing a state in which the magnetic wire 3 is arranged in the seventh embodiment. [Figure 18] FIG. 13 is a cross-sectional view showing three magnetic wires arranged in a groove that does not have a flat bottom. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] 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 an electromagnetic induction type fluxgate sensor element that uses a magnetic wire as a core, a magnetic flux response type magnetic flux sensor element, or the like other than the MI element.

[0013] The detection coil may be provided in a spiral shape along the outer circumferential surface of one of the magnetic wires via the thin-film insulator, making it easy to obtain a magnetic sensor element.

[0014] In addition, the insulator interposed between the magnetic wire and the detection coil may have a thickness equal to or less than the thickness of the detection coil over the entire circumference, in which case the detection coil can be brought close to the magnetic wire, thereby obtaining a high-output magnetic sensor element.

[0015] The magnetic wire may have a circular cross section perpendicular to the longitudinal direction, and the groove may have a semicircular cross section perpendicular to the longitudinal direction, which can more effectively prevent noise generation and provide a magnetic sensor element with superior output characteristics.

[0016] In the method for manufacturing the magnetic sensor element, the substrate has a resin layer made of a thermoplastic resin, a thermosetting resin, or a photocurable resin on its surface, and when forming the grooves on the surface of the substrate, a mold having a convex curved mold surface may be pressed against the resin layer before hardening, and the resin layer may be heated or irradiated with light. In this case, it is easy to form the grooves with high precision. Therefore, a magnetic sensor element with excellent output characteristics can be easily manufactured.

[0017] In addition, when forming the groove on the surface of the substrate, an etching resist may be provided on the surface of the substrate, and a part of the substrate may be isotropically etched in a state in which an opening narrower than the groove to be obtained is provided in the etching resist. In this case, too, the groove having a concave curved surface can be easily formed.

[0018] The magnetic sensor element according to the above aspect may have a wire group in which a plurality of the magnetic wires are arranged in parallel with each other, and the detection coil may be provided in a spiral shape around the outer periphery of the wire group. In this case, in the magnetic sensor element 1 in which a plurality of magnetic wires are arranged inside the detection coil, it is possible to prevent edges from being formed in the detection coil, and to suppress noise.

[0019] The inner wall surface of the groove may have a flat bottom surface, which makes it easier to precisely position the magnetic wires at predetermined positions in the groove, thereby making it easier to obtain the desired sensor characteristics of the magnetic sensor element.

[0020] Further, the magnetic wire has a circular cross-sectional shape perpendicular to the longitudinal direction. When the width of the flat bottom surface is W, the diameter of the magnetic wire is d, and the number of the magnetic wires included in the wire group is N, it can satisfy 1 < W / {d×(N - 1)} ≤ 10. In this case, the relative positional relationship of the plurality of magnetic wires can be set to an appropriate positional relationship.

[0021] Further, a method for manufacturing a magnetic sensor element having a wire group in which a plurality of the magnetic wires are arranged in parallel with each other, forming the groove portion on the surface of the substrate, after forming the plurality of first wiring portions on the inner wall surface of the groove portion, arranging a plurality of the magnetic wires in parallel in the groove portion via a first insulator that becomes a part of the insulator, covering a portion of the plurality of magnetic wires that is not in contact with the first insulator with a second insulator that becomes another part of the insulator, and then forming a plurality of second wiring portions on the surface of the second insulator, a method for manufacturing a magnetic sensor element can be considered.

[0022] In this case, a magnetic sensor element having a wire group in which a plurality of the magnetic wires are arranged in parallel with each other can be easily manufactured.

[0023] Further, before arranging the plurality of magnetic wires in the groove portion, the first insulator is formed on the inner wall surface of the groove portion. The first insulator has a protrusion protruding from the bottom surface of the groove portion toward the opening side, and the plurality of magnetic wires can be arranged in parallel in the groove portion with the protrusion therebetween. In this case, the step of arranging a plurality of magnetic wires in the groove portion can be facilitated.

[0024] (Embodiment 1) Embodiments related to a magnetic sensor element and a method for manufacturing the same will be described with reference to FIGS. 1 to 6. 1 and 2, the magnetic sensor element 1 of this embodiment includes a substrate 2, a magnetic wire 3, and a detection coil 4. 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.

[0025] As shown in Fig. 2, a groove 23 having a concavely curved inner wall surface is formed in the substrate 2. The detection coil 4 has a plurality of first wiring portions 41 and a plurality of second wiring portions 42. As shown in Fig. 3, the plurality of first wiring portions 41 are formed in parallel to each other on the inner wall surface of the groove portion 23. As shown in Fig. 1, the plurality of second wiring portions 42 are connected to the first wiring portions 41 and formed in parallel to each other.

[0026] 2, the magnetic wire 3 is covered with an insulator 5 and disposed in a groove 23 in which a plurality of first wiring portions 41 are formed. The second wiring portion 42 is formed, via the insulator 5, in a portion of the magnetic wire 3 exposed from the groove 23. The first wiring portion 41 and the second wiring portion 42 are smoothly connected.

[0027] Here, the state in which the first wiring part 41 and the second wiring part 42 are smoothly connected means that the two wiring parts are continuously connected in a straight line or a curved line at the connection part, and the connection part does not form a corner. More specifically, this state means, for example, a state in which the smaller angle between the tangent line of the first wiring part 41 and the tangent line of the second wiring part 42 at the connection part is 15° or less. Furthermore, the detection coil 4 formed by the first wiring part 41 and the second wiring part 42 smoothly connected to each other has a shape without corners, such as a perfect circle shape or an ellipse shape, when viewed from the longitudinal direction (X direction) of the magnetic wire 3. In this embodiment, the shape of the detection coil 4 when viewed from the longitudinal direction (X direction) of the magnetic wire 3 is substantially a perfect circle shape (see FIG. 2). That is, in this embodiment, the first wiring part 41 and the second wiring part 42 have a substantially semicircular shape when viewed from the X direction. However, the shapes of the first wiring portion 41 and the second wiring portion 42 are not limited to this, and various shapes without corners can be applied. For example, the shape of the first wiring portion 41 when viewed from the X direction can have an arc portion with an arbitrary radius of π / 2 or more.

[0028] In this embodiment, the magnetic sensor element 1 is an MI element. In the following, 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. In the Z direction, the side on which the detection coil 4 is provided with respect to the substrate 2 is described as the upper side for convenience.

[0029] The substrate 2 is a non-magnetic flat substrate. In this embodiment, the substrate 2 has a substrate body 21 and a resin layer 22 formed on the upper surface of the substrate body 21. The substrate body 21 may be, for example, a ceramic substrate such as alumina, a semiconductor wafer such as silicon, or the like.

[0030] The magnetic wire 3 is an amorphous wire, and may be a wire having a substantially circular cross section perpendicular to the longitudinal direction (X direction). In this embodiment, the magnetic wire 3 has a circular cross section perpendicular to the X direction. Accordingly, the groove 23 has a semicircular cross section perpendicular to the X direction. The diameter of the magnetic wire 3 may be, for example, 1 to 50 μm.

[0031] The detection coil 4 is made of a thin film conductor having a thickness of, for example, about 1 to 10 μm. That is, the multiple first wiring parts 41 and the multiple second wiring parts 42 are each made of a thin film conductor. The detection coil 4 is provided in a spiral shape along the outer circumferential surface of one magnetic wire 3, with a thin film insulator 5 interposed therebetween.

[0032] The insulator 5 interposed between the magnetic wire 3 and the detection coil 4 has a thickness equal to or less than the thickness of the detection coil 4 over the entire circumference. The insulator 5 interposed between the magnetic wire 3 and the detection coil 4 has a thickness of, for example, about 0.5 to 5 μm. The insulator 5 interposed between the magnetic wire 3 and the detection coil 4 has a substantially uniform thickness over the entire circumference. Note that the thickness of the insulator 5 may be greater than the thickness of the detection coil 4 not between the magnetic wire 3 and the detection coil 4 but in a portion where the detection coil 4 is not formed (for example, a portion between the coil wiring). The insulator 5 is made of a resin material such as a phenolic resin.

[0033] Although not shown in the figure, terminals are connected to both ends of the detection coil 4 and both ends of the magnetic wire 3, respectively.

[0034] In manufacturing the magnetic sensor element 1 of this embodiment, as shown in steps S1 and S2 of FIG. 4, a groove 23 is formed on the surface of the substrate 2. Then, as shown in step S3 of the same figure, a plurality of first wiring parts 41 are formed on the inner wall surface of the groove 23 (see also FIG. 3). Thereafter, as shown in step S4 of FIG. 4 and step S5 of FIG. 5, the magnetic wire 3 is placed in the groove 23 via the first insulator 51 which becomes a part of the insulator 5. Next, as shown in steps S6 and S7 of FIG. 5, a plurality of second wiring parts 42 are formed on the part of the magnetic wire 3 exposed from the groove 23 via the second insulator 52 which becomes another part of the insulator 5 (see also FIG. 1).

[0035] Next, an example of a method for manufacturing the magnetic sensor element 1 of this embodiment will be specifically described with reference to FIGS. 4, a resin layer 22 is formed on the upper surface of the substrate body 21. Next, as shown in step S2, a groove portion 23 is formed in the resin layer 22. The groove portion 23 is formed so that a cross-sectional shape perpendicular to the X direction is substantially semicircular.

[0036] The shape and size of the groove 23 are appropriately designed according to the shape and diameter of the magnetic wire 3. In this embodiment, the shape of the cross section of the magnetic wire 3 perpendicular to the X direction is substantially a perfect circle, so the shape of the cross section of the groove 23 perpendicular to the X direction is semicircular. The radius of curvature of the semicircular shape of the groove 23 is designed to be slightly larger than the radius of the magnetic wire 3. It is desirable that the radius of curvature of the groove 23 is approximately equal to the sum of the thickness of the detection coil 4 and the thickness of the insulator 5, rather than the radius of the magnetic wire 3.

[0037] The grooves 23 can be formed by using, for example, a nanoimprint technique (see FIG. 6) described later. By using the nanoimprint technique, the grooves 23 can be formed to the desired dimensions and shape.

[0038] Next, as shown in step S3 of FIG. 4, first wiring parts 41 are formed on the inner wall surface of the groove part 23. The first wiring parts 41 are formed by patterning using photolithography. That is, a plurality of first wiring parts 41 are formed by sputtering, forming a plating resist, plating, etching, etc. The plurality of first wiring parts 41 are arranged in parallel in the X direction as shown in FIG.

[0039] 4, a first insulator 51 is formed on the inner wall surface of the groove portion 23 so as to cover the first wiring portions 41. The first insulator 51 constitutes a part of the insulator 5 described above. The thickness of the first insulator 51 covering the first wiring portions 41 is smaller than the thickness of the first wiring portions 41.

[0040] Next, as shown in step S5 of FIG. 5, the magnetic wire 3 is placed on the first insulator 51. That is, the magnetic wire 3 is placed in the groove 23 of the substrate 2 via the first wiring portion 41 and the first insulator 51. Approximately the lower half of the magnetic wire 3 is placed in the groove 23. The outer peripheral surface of the magnetic wire 3 is in close contact with the first insulator 51.

[0041] 5, a second insulator 52 is formed on approximately the upper half of the outer circumferential surface of the magnetic wire 3. The second insulator 52 constitutes a part of the above-mentioned insulator 5. The second insulator 52 is smoothly connected to the first insulator 51 to form the insulator 5 that covers the entire periphery of the magnetic wire 3.

[0042] Next, as shown in step S7 of Fig. 5, a plurality of second wiring portions 42 are formed on the second insulator 52 (see also Fig. 1). Like the first wiring portion 41, the second wiring portion 42 can also be patterned using photolithography. The second wiring portions 42 are smoothly connected to the first wiring portions 41 to form a spiral detection coil 4.

[0043] The grooves 23 can be formed in the substrate 2 in the above steps S1 and S2 by using a nanoimprint technique as shown in Fig. 6. For this purpose, the resin layer 22 applied in the above step S1 is made of, for example, a thermoplastic resin, a thermosetting resin, or a photocurable resin. That is, when thermal nanoimprinting is used, a thermoplastic resin or a thermosetting resin is used as the resin layer 22. When photo nanoimprinting is used, a photocurable resin is used as the resin layer 22.

[0044] As shown in FIG. 6, the nanoimprint technique uses a mold 6 having a mold surface 61 for forming the grooves 23.

[0045] When using thermal nanoimprinting, the mold 6 and the substrate 2 are heated to a temperature equal to or higher than the glass transition temperature of the resin layer 22 made of a thermoplastic resin or a thermosetting resin. In this state, the mold surface 61 of the mold 6 is pressed against the upper surface of the resin layer 22 of the substrate 2. Thereafter, the substrate 2 is cooled and then released from the mold. As a result, the shape of the mold surface 61 is transferred to the resin layer 22 of the substrate 2, and the grooves 23 are formed.

[0046] When using photo-nanoimprinting, the mold surface 61 of the mold 6 is pressed against the upper surface of the resin layer 22 made of a photocurable resin. In this state, the resin layer 22 is irradiated with ultraviolet light. For this reason, the mold 6 used is one that is transparent to the irradiated ultraviolet light. After the resin layer 22 is cured, the substrate 2 is released from the mold 6. As a result, the shape of the mold surface 61 is transferred to the resin layer 22 of the substrate 2, and the grooves 23 are formed.

[0047] Next, the effects of this embodiment will be described. In the magnetic sensor element 1 of this embodiment, a groove 23 having a concavely curved inner wall surface is formed in the substrate 2. Therefore, it is possible to prevent edges from being formed in the first wiring portion 41 formed on the inner wall surface of the groove 23. In addition, the first wiring portion 41 and the second wiring portion 42 are smoothly connected. This makes it possible to prevent edges from being formed at the joint between the first wiring portion 41 and the second wiring portion 42. As a result, it is possible to prevent edges from being formed in the detection coil 4, and to suppress the generation of noise.

[0048] For example, in the case of a magnetic sensor element 9 of a comparative embodiment shown in Fig. 7, when a detection coil 94 is formed by providing a thin film conductor pattern on the inner wall surface of a groove 923 having a rectangular cross section, an edge E is formed in the detection coil 94. To obtain this magnetic sensor element 9, a groove 923 having a rectangular cross section is formed in a substrate 92. A thin film conductor pattern 941 is formed on the inner wall surface of this groove 923, a magnetic wire 93 is placed in the groove 923, and an embedded insulating layer 95 is filled in the groove 923. A thin film conductor pattern 942 is formed on the upper surface of this embedded insulating layer 95. The thin film conductor pattern 941 and the thin film conductor pattern 942 are connected to form the detection coil 94.

[0049] In the case of such a magnetic sensor element 9, an edge is formed at a position indicated by the symbol E in the detection coil 94. This edge E is likely to become a cause of noise. In the magnetic sensor element 1 of this embodiment, it is possible to prevent such an edge from being formed in the detection coil 4 as described above.

[0050] Moreover, the insulator 5 interposed between the magnetic wire 3 and the detection coil 4 has a thickness around the entire circumference that is equal to or less than the thickness of the detection coil 4. This allows the detection coil 4 to be brought closer to the magnetic wire 3, and a high-output magnetic sensor element 1 can be obtained.

[0051] Moreover, the magnetic wire 3 has a circular cross section perpendicular to the longitudinal direction, and the groove 23 has a semicircular cross section perpendicular to the longitudinal direction. This makes it possible to more effectively prevent noise generation, and to obtain a magnetic sensor element 1 with better output characteristics. The cross section of the groove 23 may have a shape other than a semicircular shape, such as an elliptical shape, as long as it has no corners.

[0052] Furthermore, when forming the grooves 23 on the surface of the substrate 2, a mold 6 having a convexly curved mold surface 61 is pressed against the resin layer 22 before hardening, and the resin layer 22 is heated or irradiated with light. That is, the grooves 23 are formed using nanoimprint technology. This makes it easy to form the grooves 23 with high accuracy. Therefore, a magnetic sensor element 1 with excellent output characteristics can be easily manufactured.

[0053] As described above, according to the present embodiment, it is possible to provide a magnetic sensor element that is less susceptible to noise and a manufacturing method thereof.

[0054] (Embodiment 2) This embodiment is a modified embodiment of the method for manufacturing a magnetic sensor element, and differs from the first embodiment in that an insulator 5 is formed in advance on the outer circumferential surface of the magnetic wire 3, as shown in Figs. That is, steps S4 to S6 (see FIGS. 4 and 5) of the method for manufacturing a magnetic sensor element according to the first embodiment are modified as follows.

[0055] As shown in Fig. 8, a plurality of first wiring portions 41 are formed on the inner wall surface of the groove portion 23 of the substrate 2. Up to this point, the steps are the same as steps S1 to S3 (see Fig. 4) in the manufacturing method shown in embodiment 1. Meanwhile, an insulator 5 is formed on the outer circumferential surface of the magnetic wire 3. The insulator 5 is formed uniformly around the entire circumference of the magnetic wire 3.

[0056] Then, the magnetic wire 3 covered with the insulator 5 is placed in the groove 23 in which the first wiring portion 41 is formed, as shown in Fig. 9. Thereafter, similarly to step S7 (see Fig. 5) in the manufacturing method shown in the first embodiment, a plurality of second wiring portions 42 are formed on the outer surface of the magnetic wire 3 exposed from the groove 23. As a result, a spiral detection coil 4 is formed around the magnetic wire 3 with the insulator 5 interposed therebetween.

[0057] As a result, a magnetic sensor element 1 (see FIGS. 1 and 2) having the same configuration as in embodiment 1 is obtained. The rest is the same as 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. In this embodiment as well, the same effects as those in the first embodiment can be obtained.

[0058] (Embodiment 3) In this embodiment, as shown in FIG. 10, isotropic etching is used to form a groove 23 in a substrate 2. In the embodiment shown in FIG. That is, an etching resist 71 is provided on the surface of the substrate 2, and an opening 711 narrower than the groove 23 to be obtained is provided in the etching resist 71. In this state, a part of the substrate 2 is isotropically etched.

[0059] In this embodiment, the substrate 2 is made of single crystal silicon (Si) provided with a coating 24 of silicon oxide (SiO2).

[0060] An etching resist 71 is applied to the upper surface of the substrate 2, and a pattern of an opening 711 is formed in a part of the etching resist according to the position and range of the groove 23 to be obtained. In this state, the substrate 2 is etched with an etching solution made of a mixture of hydrofluoric acid (HF) and nitric acid (HNO3). As a result, the substrate 2 made of single crystal silicon is isotropically etched. The isotropic etching proceeds from the openings 711 of the etching resist 71 not only in the thickness direction (Z direction) of the substrate 2 but also in the Y direction.

[0061] The shape of the etched portion can be adjusted by adjusting the compounding ratio of hydrofluoric acid and nitric acid in the etching solution. In general, the radius of curvature of the corner can be increased by increasing the compounding ratio of nitric acid. Therefore, the compounding ratio of hydrofluoric acid and nitric acid in the etching solution, the etching time, the temperature of the etching solution, and further the size of the opening 711 of the etching resist can be appropriately adjusted to form the groove 23 of appropriate size and shape.

[0062] The rest is the same as in the first embodiment. In this embodiment as well, it is possible to provide a magnetic sensor element that is less susceptible to noise and a manufacturing method thereof.

[0063] (Embodiment 4) In this embodiment, as shown in Fig. 11, a groove portion 23 of a substrate 2 is formed by utilizing grayscale exposure. The substrate 2 is a non-magnetic flat substrate. In this embodiment, similar to the first embodiment, the substrate 2 has a substrate body 21 and a resin layer 22 formed on the upper surface of the substrate body 21. The substrate body 21 may be, for example, a ceramic substrate such as alumina, a semiconductor wafer such as silicon, or the like.

[0064] That is, first, a photosensitive resin layer 22 is formed on the upper surface of the substrate body 21. In this embodiment, an example is shown in which a positive photosensitive resin is used as the resin layer 22. This photosensitive resin layer 22 is irradiated with ultraviolet light through a photomask 72, thereby exposing the resin layer 22 to light.

[0065] The photomask 72 has a mask pattern 721 formed thereon that corresponds to the grooves 23. That is, the photomask 72 has the mask pattern 721 that transmits ultraviolet light at the positions where the grooves 23 are to be formed, and the other regions do not transmit ultraviolet light. The mask pattern 721 has a gradation, and the transmittance of ultraviolet light varies depending on the position. Specifically, the mask pattern 721 is configured so that the light transmittance decreases from the center in the Y direction toward the outside.

[0066] As a result, as shown in FIG. 11, the ultraviolet light irradiated to the resin layer 22 through the photomask 72 is strong in the center in the Y direction and weaker toward the outside. Therefore, the depth of the resin layer 22 exposed to light varies depending on the position in the Y direction. As a result, the grooves 23 formed by the development process have different depths depending on the position in the Y direction. That is, the grooves 23 are deep in the center in the Y direction and shallower toward the outside. By adjusting the gradation of the photomask 72, the grooves 23 having a desired cross-sectional shape can be obtained. That is, as shown in FIG. 10, the grooves 23 can be formed having inner walls that are concavely curved, such as a substantially semicircular cross-section.

[0067] The rest is the same as in the first embodiment. In this embodiment as well, it is possible to provide a magnetic sensor element that is less susceptible to noise and a manufacturing method thereof.

[0068] In this embodiment, an example is shown in which the resin layer 22 is made of a positive photosensitive resin, but even if a negative photosensitive resin is used for the resin layer, the groove portion can be formed in substantially the same manner.

[0069] (Embodiment 5) As shown in Figs. 12 and 13, this embodiment is a magnetic sensor element 1 having a plurality of magnetic wires 3 arranged in parallel with each other. The magnetic sensor element 1 of this embodiment has a wire group 30 in which a plurality of magnetic wires 3 are arranged in parallel to one another. The detection coil 4 is provided around the outer periphery of the wire group 30 in a spiral shape.

[0070] In this embodiment, the wire group 30 has two magnetic wires 3. The two magnetic wires 3 are arranged side by side in the Y direction. As shown in Fig. 13, the inner wall surface of the groove portion 23 has a flat bottom surface 231 having a flat surface shape. The inner wall surface of the groove portion 23 has arc-shaped concave curved surfaces 232 on both sides of the flat bottom surface 231 in the Y direction. The two magnetic wires 3 are arranged so as to run along the inner wall surface of the groove portion 23 from the ends of the flat bottom surface 231 to the concave curved surfaces 232.

[0071] The magnetic wire 3 has a circular cross-sectional shape perpendicular to the longitudinal direction (X direction). When the width of the flat bottom surface 231 is W, the diameter of the magnetic wire 3 is d, and the number of magnetic wires included in the wire group 30 is N, it is desirable to satisfy 1 < W / {d×(N - 1)} ≦ 10. In this embodiment, since N = 2, it is desirable to satisfy 1 < W / d ≦ 10. More preferably, 1 < W / {d×(N - 1)} ≦ 2, and in this embodiment where N = 2, it is even more preferable to satisfy 1 < W / d ≦ 2.

[0072] Also, it is particularly preferable that 1 < W / {d×(N - 1)} ≦ 1.5, that is, in this embodiment, 1 < W / d ≦ 1.5.

[0073] Regarding the method for manufacturing the magnetic sensor element 1 of this embodiment, first, an overview will be described. A groove portion 23 is formed on the surface of the substrate 2 (see steps S01 and S02 in FIG. 14).

[0074] Thereafter, a plurality of first wiring portions 41 are formed on the inner wall surface of the groove portion 23 (see step S03 in FIG. 14). Thereafter, a plurality of magnetic wires 3 are arranged in parallel in the groove portion 23 via a first insulator 51 which is a part of the insulator 5 (see step S05 in FIG. 15).

[0075] Thereafter, portions of the plurality of magnetic wires 3 that are not in contact with the first insulator 51 are covered by a second insulator 52 which is another part of the insulator 5 (step S06 in FIG. 15). Thereafter, a plurality of second wiring portions 42 are formed on the surface of the second insulator 52 (step S07 in FIG. 15).

[0076] An example of the manufacturing method of the magnetic sensor element of this embodiment will be specifically described with reference to FIGS. 14 and 15. First, as shown in step S01 of FIG. 14, a resin layer 22 is formed on the upper surface of the substrate body 21. Next, as shown in step S02, a groove portion 23 is formed in the resin layer 22. The groove portion 23 is formed such that the width in the Y direction is larger than twice the diameter of the magnetic wire 3. The depth of the groove portion 23 in the Z direction is set to be equal to or less than the diameter of the magnetic wire 3.

[0077] Also, as described above, when the width of the flat bottom surface 231 is W, the diameter of the magnetic wire 3 is d, and the number of magnetic wires 3 included in the wire group 30 is N, it is preferable to satisfy 1 < W / {d×(N - 1)} ≤ 10 (see FIG. 13). Furthermore, it is more preferable to satisfy 1 < W / {d×(N - 1)} ≤ 2. In this embodiment, since N = 2, it is preferable to satisfy 1 < W / d ≤ 10, and more preferably, to satisfy 1 < W / d ≤ 2.

[0078] Next, as shown in step S03 of FIG. 14, a first wiring portion 41 is formed on the inner wall surface of the groove portion 23. The first wiring portion 41 can be pattern-formed using photolithography.

[0079] Next, as shown in step S04 of FIG. 14, a first insulator 51 is formed.

[0080] Next, as shown in step S05 of FIG. 15, two magnetic wires 3 are placed on the first insulator 51. That is, in the groove portion 23 of the substrate 2, two magnetic wires 3 are arranged via the first wiring portion 41 and the first insulator 51. Approximately the lower half of the magnetic wire 3 is arranged in the groove portion 23. A part of the outer peripheral surface of the magnetic wire 3 is in close contact with the first insulator 51. The two magnetic wires 3 are arranged parallel to each other.

[0081] Next, as shown in step S06 of FIG. 15, a second insulator 52 is formed so as to cover the magnetic wire 3 from above and fill the groove portion 23. The second insulator 52 is smoothly connected to the first insulator 51 to form an insulator 5 that covers the entire circumference of the magnetic wire 3.

[0082] Next, as shown in step S07 of FIG. 15, a second wiring portion 42 is formed on the second insulator 52. The rest is the same as that of the first embodiment.

[0083] In the case of this embodiment, by providing a plurality of magnetic wires 3, the sensor output can be increased. Further, for example, compared with the case where a plurality of magnetic sensor elements 1 shown in the first embodiment are arranged side by side, the electrical resistance of the coil can be suppressed, and the resistance variation can be suppressed.

[0084] Also, in the magnetic sensor element 1 in which a plurality of magnetic wires 3 are arranged inside the detection coil 4, it is possible to prevent an edge from being formed in the detection coil 4, and noise can be suppressed.

[0085] Further, since the inner wall surface of the groove portion 23 has a flat bottom surface 231, it becomes easy to accurately arrange a plurality of magnetic wires 3 at a predetermined position inside the groove portion 23. Thereby, it becomes easy to obtain desired sensor characteristics of the magnetic sensor element 1. That is, when there is no flat bottom surface 231 in the groove portion 23, when the magnetic wire 3 is arranged in the groove portion 23, it is conceivable that the magnetic wire 3 is displaced from a predetermined position due to the inclination of the inner wall surface. By providing the flat bottom surface 231 in the groove portion 23, it is easy to suppress such displacement of the magnetic wire 3.

[0086] Also, when the width W of the flat bottom surface 231, the diameter d of the magnetic wire 3, and the number of magnetic wires 3 included in the wire group 30 are N, 1 < W / {d×(N - 1)} ≤ 10 is satisfied. Thereby, the relative positional relationship of the plurality of magnetic wires 3 can be set to an appropriate positional relationship.

[0087] By 1 < W / {d×(N - 1)}, a sufficient interval between the magnetic wires 3 can be ensured, and it becomes easy to ensure electrical insulation between them. When a current is passed through a plurality of magnetic wires 3 in the same direction, if the magnetic wires 3 come into contact with and separate from each other repeatedly, it may cause noise. To prevent this, it is preferable to set 1 < W / {d×(N - 1)}.

[0088] By satisfying W / {d×(N-1)}≦10, the spatial resolution of the magnetic sensor element 1 can be sufficiently ensured. In other words, if the width W of the flat bottom surface 231 is too large and the positional relationship between the multiple magnetic wires 3 becomes too wide, it becomes difficult to detect a local magnetic field, and it becomes difficult to obtain high spatial resolution. From this viewpoint, it is preferable to satisfy W / {d×(N-1)}≦10.

[0089] In addition, the same effects as those of the first embodiment are achieved.

[0090] (Embodiment 6) This embodiment is a method for manufacturing a magnetic sensor element 1 in which a first insulator 51 has a protrusion 511 protruding from the bottom surface of a groove 23 toward the opening side, as shown in FIG.

[0091] Before arranging the multiple magnetic wires 3 in the groove 23, a first insulator 51 is formed on the inner wall surface of the groove 23. This first insulator 51 has a protrusion 511. The multiple magnetic wires 3 are arranged in parallel in the groove 23 with the protrusion 511 between them.

[0092] That is, when forming the first insulator 51, the protrusion 511 is provided as a part thereof. The protrusion 511 can have a height, for example, approximately equal to the radius of the magnetic wire 3. In this embodiment, the number of magnetic wires 3 arranged in the groove 23, i.e., the number of magnetic wires 3 included in the wire group 30, is two, so the protrusion 511 is formed approximately at the center in the width direction of the groove 23. The protrusion 511 protrudes upward in the Z direction from the flat bottom surface 231 of the groove 23.

[0093] The protrusion 511 may be formed continuously and elongated in the X direction, or a plurality of protrusions 511 independent of one another may be arranged side by side in the X direction, for example. The rest is the same as in the first embodiment.

[0094] In the case of this embodiment, the process of arranging a plurality of magnetic wires 3 in the groove portion 23 can be facilitated. That is, when a plurality of magnetic wires 3 are arranged in the groove portion 23, the protrusion 511 exhibits a guiding function, and the movement of the magnetic wires 3 in the Y direction can be suppressed. In particular, the movement of adjacent magnetic wires 3 in the direction of approaching each other can be restricted, and it is easy to ensure insulation between the magnetic wires 3. In addition, it has the same effects as those of the first embodiment.

[0095] (Embodiment 7) In this embodiment, as shown in FIG. 17, the wire group 30 is in the form of the magnetic sensor element 1 having three magnetic wires 3. By increasing the number of magnetic wires 3, the sensor output can be increased. Also, the signal-to-noise ratio (i.e., S / N ratio) can be improved.

[0096] Also in the magnetic sensor element 1 of this embodiment, the groove portion 23 has a flat bottom surface 231. Also in this embodiment, the width W of the flat bottom surface 231, the diameter d of the magnetic wire 3, and the number N of magnetic wires 3 included in the wire group 30 satisfy 1 < W / {d×(N - 1)} ≤ 10. Therefore, in this embodiment, 1 < W / 2d ≤ 10 is satisfied.

[0097] All three magnetic wires 3 are arranged on the flat bottom surface 231. However, the magnetic wires 3 arranged at both ends in the Y direction also follow the concave curved surface 232. The rest is the same as that of the first embodiment.

[0098] In the magnetic sensor element 1 having three or more magnetic wires 3 as in this embodiment, by providing the flat bottom surface 231 in the groove portion 23, the advantage that the Z-direction positions of all the magnetic wires 3 can be aligned is also obtained.

[0099] That is, when three or more magnetic wires 3 are arranged in the groove 23, if the groove 23 does not have a sufficiently wide flat bottom surface 231, the height positions in the Z direction will be misaligned among the multiple magnetic wires 3, for example, as shown in Fig. 18. In contrast, when the groove 23 has a sufficiently wide flat bottom surface 231 as in this embodiment, the height positions in the Z direction of the multiple magnetic wires 3 can be aligned.

[0100] As an effect of providing the groove 23 with a sufficiently large flat bottom surface 231, the magnetic wire 3 becomes less likely to shift in the Y direction, as described in the first embodiment above. In addition, the same effects as those of the first embodiment are achieved.

[0101] In the manufacturing method of the magnetic sensor element according to each embodiment described above, at least one of the steps of forming the first insulator and the second insulator may be formed by a photo-nanoimprint method, which can form the insulator with higher accuracy.

[0102] 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.

[0103] The features of the present disclosure are as follows: [1] A magnetic sensor element comprising: a substrate; a magnetic wire disposed on the substrate; and a detection coil made of a thin-film conductor spirally disposed around the magnetic wire, a groove having a concave inner wall surface is formed in the substrate; the detection coil has a plurality of first wiring portions formed in parallel to one another on an inner wall surface of the groove portion, and a plurality of second wiring portions connected to the first wiring portions and formed in parallel to one another, the magnetic wire is covered with an insulator and disposed in the groove in which the first wiring portions are formed, the second wiring portion is formed on a portion of the magnetic wire exposed from the groove portion via the insulator, A magnetic sensor element in which the first wiring portion and the second wiring portion are smoothly connected. [2] The detection coil is provided in a spiral shape along the outer peripheral surface of one magnetic wire via the thin-film insulator, according to claim 1 of the magnetic sensor element. [3] The insulator interposed between the magnetic wire and the detection coil has a film thickness equal to or less than the film thickness of the detection coil over the entire circumference, according to [2] of the magnetic sensor element. [4] The magnetic wire has a circular cross-sectional shape perpendicular to the longitudinal direction, and the groove portion has a semi-circular cross-sectional shape perpendicular to the longitudinal direction, according to [2] or [3] of the magnetic sensor element. [5] Having a wire group in which a plurality of the magnetic wires are arranged in parallel with each other, and the detection coil is provided in a spiral shape on the outer periphery of the wire group, according to [1] of the magnetic sensor element. [6] The inner wall surface of the groove portion has a flat bottom surface in a flat surface shape, according to [5] of the magnetic sensor element. [7] The magnetic wire has a circular cross-sectional shape perpendicular to the longitudinal direction. When the width of the flat bottom surface is W, the diameter of the magnetic wire is d, and the number of the magnetic wires included in the wire group is N, it satisfies 1 < W / {d×(N - 1)} ≦ 10, according to [6] of the magnetic sensor element. [8] A method for manufacturing the magnetic sensor element according to any one of [1] to [4], forming the groove portion on the surface of the substrate, after forming a plurality of the first wiring portions on the inner wall surface of the groove portion, disposing the magnetic wire in the groove portion via a first insulator that becomes a part of the insulator, forming a plurality of the second wiring portions on a portion of the magnetic wire exposed from the groove portion via a second insulator that becomes the other part of the insulator, a method for manufacturing a magnetic sensor element. [9] A method for manufacturing the magnetic sensor element according to any one of [5] to [7], forming the groove portion on the surface of the substrate, a plurality of the first wiring portions are formed on the inner wall surface of the groove portion, and then the plurality of the magnetic wires are arranged in parallel in the groove portion via a first insulator that becomes a part of the insulator; A method for manufacturing a magnetic sensor element, comprising covering portions of the multiple magnetic wires that are not in contact with the first insulator with a second insulator that becomes another part of the insulator, and then forming multiple second wiring portions on a surface of the second insulator.

[10] A method for manufacturing a magnetic sensor element as described in [9], wherein before arranging the multiple magnetic wires in the groove, the first insulator is formed on the inner wall surface of the groove, the first insulator has a protrusion protruding from the bottom surface of the groove toward an opening side, and the multiple magnetic wires are arranged in parallel in the groove, sandwiched between the protrusions.

[11] The method for manufacturing a magnetic sensor element described in any one of [8] to

[10] , wherein the substrate has a resin layer made of a thermoplastic resin, a thermosetting resin or a photocurable resin on a surface thereof, and when forming the groove portion on the surface of the substrate, a mold having a convex curved mold surface is pressed against the resin layer before hardening, and the resin layer is heated or irradiated with light.

[12] The method for manufacturing a magnetic sensor element described in any one of [8] to

[10] , wherein when forming the groove on the surface of the substrate, an etching resist is provided on the surface of the substrate, and a portion of the substrate is isotropically etched while an opening narrower than the groove to be obtained is provided in the etching resist. [Explanation of symbols]

[0104] 1. Magnetic sensor element 2. Board 23 Groove 3 Magnetic Wire 4 Detection coil 41 1st wiring section 42 2nd wiring section 5. Insulation

Claims

1. A magnetic sensor element comprising: a substrate; a magnetic wire disposed on the substrate; and a detection coil made of a thin film conductor spirally disposed around the magnetic wire, a groove having a concave inner wall surface is formed in the substrate; the detection coil has a plurality of first wiring portions formed in parallel to one another on an inner wall surface of the groove portion, and a plurality of second wiring portions connected to the first wiring portions and formed in parallel to one another, the magnetic wire is covered with an insulator and disposed in the groove in which the first wiring portions are formed, the second wiring portion is formed on a portion of the magnetic wire exposed from the groove portion via the insulator, The first wiring portion and the second wiring portion are smoothly connected to each other.

2. 2. The magnetic sensor element according to claim 1, wherein the detection coil is provided in a spiral shape along an outer circumferential surface of one of the magnetic wires, with the thin-film insulator interposed therebetween.

3. 3. The magnetic sensor element according to claim 2, wherein the insulator interposed between the magnetic wire and the detection coil has a thickness equal to or smaller than a thickness of the detection coil over the entire periphery.

4. 4. The magnetic sensor element according to claim 2, wherein the magnetic wire has a circular cross section perpendicular to the longitudinal direction, and the groove has a semicircular cross section perpendicular to the longitudinal direction.

5. 2. The magnetic sensor element according to claim 1, further comprising a wire group in which a plurality of the magnetic wires are arranged in parallel to each other, and the detection coil is provided in a spiral shape around an outer periphery of the wire group.

6. The magnetic sensor element according to claim 5 , wherein the inner wall surface of the groove has a flat bottom surface.

7. The magnetic sensor element of claim 6, wherein the magnetic wire has a circular cross-sectional shape perpendicular to the longitudinal direction, and the width of the flat bottom surface is W, the diameter of the magnetic wire is d, and the number of the magnetic wires included in the wire group is N, satisfying 1<W / {d×(N-1)}≦10.

8. A method for manufacturing a magnetic sensor element according to claim 1 or 2, comprising the steps of: forming the groove portion on the surface of the substrate; After forming a plurality of the first wiring portions on the inner wall surface of the groove portion, the magnetic wire is disposed in the groove portion via a first insulator that becomes a part of the insulator; A method for manufacturing a magnetic sensor element, comprising forming a plurality of second wiring portions on a portion of the magnetic wire exposed from the groove portion via a second insulator that becomes another part of the insulator.

9. A method for manufacturing a magnetic sensor element according to claim 5, comprising the steps of: forming the groove portion on the surface of the substrate; a plurality of the first wiring portions are formed on the inner wall surface of the groove portion, and then the plurality of the magnetic wires are arranged in parallel in the groove portion via a first insulator that becomes a part of the insulator; A method for manufacturing a magnetic sensor element, comprising covering portions of multiple magnetic wires that are not in contact with the first insulator with a second insulator that becomes another part of the insulator, and then forming multiple second wiring portions on the surface of the second insulator.

10. 10. The method for manufacturing a magnetic sensor element according to claim 9, wherein before arranging the multiple magnetic wires in the groove, the first insulator is formed on an inner wall surface of the groove, the first insulator has a protrusion protruding from a bottom surface of the groove toward an opening side, and the multiple magnetic wires are arranged in parallel in the groove, sandwiching the protrusion.

11. 9. The method for manufacturing a magnetic sensor element according to claim 8, wherein the substrate has a resin layer made of a thermoplastic resin, a thermosetting resin, or a photocurable resin on a surface thereof, and when forming the groove portion on the surface of the substrate, a mold having a convex curved mold surface is pressed against the resin layer before hardening, and the resin layer is heated or irradiated with light.

12. 9. The method for manufacturing a magnetic sensor element according to claim 8, wherein when forming the groove portion on the surface of the substrate, an etching resist is provided on the surface of the substrate, and a portion of the substrate is isotropically etched while an opening narrower than the groove portion to be obtained is provided in the etching resist.

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