Magnetic sensor element and manufacturing method of the same

Abstract

To provide a magnetic sensor element capable of easily forming a detection coil, and a manufacturing method of the same.SOLUTION: A magnetic sensor element 1 comprises: a substrate 2; a magnetic wire 3 disposed on the substrate 2; and a detection coil 4 spirally provided on an outer periphery of the magnetic wire 3. The detection coil 4 includes a plurality of first wiring parts 41 formed in parallel to each other on the substrate 2 side and a plurality of second wiring parts 42 formed in parallel to each other on a side of the first wiring part 41 opposite to the substrate 2, the first wiring parts and the second wiring parts connected to each other. The first wiring part 41 is provided with a central recess 412 between two connection portions 411 connected to the second wiring part 42. The magnetic wire 3 is disposed via an insulation material 51 in the central recess 412 in each of the plurality of first wiring parts 41. A thickness of the connection portion 411 in a normal direction Z of the substrate 2 is larger than a depth of the central recess 412.SELECTED DRAWING: Figure 3

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 wound in a spiral shape around the magnetic wire. The detection coil made of the thin-film conductor is formed so as to go around the magnetic wire. Therefore, the thin-film conductor is patterned over different heights in the normal direction of the substrate. In Patent Document 1, a groove is provided in the 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 that fills the groove and embeds the magnetic wire. The detection coil is formed by connecting these conductor patterns. [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, it is difficult to precisely form the thin-film conductor pattern inside the groove or at positions at different heights in the normal direction of the substrate, so there is a demand for a magnetic sensor element that can easily form a detection coil and a method for manufacturing the same.

[0005] The present invention has been made in view of the above-mentioned problems, and aims to provide a magnetic sensor element that allows a detection coil to be easily formed, and a manufacturing method thereof. [Means for solving the problem]

[0006] 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 spirally disposed around the magnetic wire, the detection coil is configured by connecting a plurality of first wiring parts formed in parallel to each other on the substrate side and a plurality of second wiring parts formed in parallel to each other on the side of the first wiring parts opposite to the substrate, the first wiring portion has a central recess between two connection sites connected to the second wiring portion, the magnetic wire is disposed in the central recess of the first wiring portion via an insulating material; The thickness of the connection portion in the normal direction of the substrate is greater than the depth of the central recess in the magnetic sensor element.

[0007] Another aspect of the present invention is a method for manufacturing the magnetic sensor element, comprising the steps of: forming a plurality of thick-film conductor portions in parallel with each other on a surface of the substrate; The method for manufacturing a magnetic sensor element includes forming the central recess in each of the thick film conductor portions to form a plurality of the first wiring portions. Effect of the Invention

[0008] In the magnetic sensor element, the first wiring portion is provided with the central recess. The magnetic wire is disposed in the central recess of the plurality of first wiring portions via an insulating material. Therefore, there is no need to provide a step on the surface of the substrate on which the first wiring portion is formed, so the first wiring portion can be formed easily and accurately. In addition, since the magnetic wire is disposed in the central recess of the first wiring portion, the base on which the second wiring portion is formed can also suppress steps. As a result, the detection coil can be easily formed.

[0009] As described above, according to the above aspect, it is possible to provide a magnetic sensor element capable of easily forming a detection coil, and a manufacturing method thereof. [Brief description of the drawings]

[0010] [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] 4A is an explanatory plan view of the stage in which a thick-film conductor portion has been formed in embodiment 1, FIG. 4B is an explanatory cross-sectional view taken along line IVb-IVb in (a), and FIG. 4C is an explanatory cross-sectional view taken along line IVc-IVc in (b). [Diagram 5] 1A is an explanatory plan view of a stage in which an etching resist has been formed in embodiment 1; FIG. 1B is an explanatory cross-sectional view taken along line Vb-Vb in (a); and FIG. 1C is an explanatory cross-sectional view taken along line Vc-Vc in (b). [Figure 6] 6A is an explanatory plan view of the stage in which a central recess is formed in the first embodiment, FIG. 6B is an explanatory cross-sectional view taken along line VIb-VIb in (a), and FIG. 6C is an explanatory cross-sectional view taken along line VIc-VIc in (b). [Figure 7] 7A is an explanatory plan view of the stage after removing the etching resist and the plating resist in embodiment 1, (b) is an explanatory cross-sectional view taken along line VIIb-VIIb in (a), and (c) is an explanatory cross-sectional view taken along line VIIc-VIIc in (b). FIG. [Figure 8] FIG. 1A is an explanatory plan view of an insulating material formed under a magnetic wire in a first embodiment; FIG. 1B is an explanatory cross-sectional view taken along line VIIIb-VIIIb in (a); and FIG. 1C is an explanatory cross-sectional view taken along line VIIIc-VIIIc in (b). [Figure 9] 9A is a plan view of an insulating material formed to cover the magnetic wire in the first embodiment, FIG. 9B is a cross-sectional view taken along line IXb-IXb in (a), and FIG. 9C is a cross-sectional view taken along line IXc-IXc in (b). [Figure 10] 1A is a plan view of an insulating material formed on a substrate around a detection coil according to a first embodiment, FIG. 1B is a cross-sectional view taken along line Xb-Xb in (a), and FIG. 1C is a cross-sectional view taken along line Xc-Xc in (b). [Figure 11]1A is an explanatory plan view of a state in which a second wiring portion has been formed in embodiment 1, FIG. 1B is an explanatory cross-sectional view taken along line XIb-XIb in (a), and FIG. 1C is an explanatory cross-sectional view taken along line XIc-XIc in (b). [Figure 12] FIG. 11 is a cross-sectional view of a magnetic sensor element according to a second embodiment. [Figure 13] FIG. 11 is a plan view of a magnetic sensor element according to a third embodiment. [Figure 14] FIG. 14 is a cross-sectional view taken along line XIV-XIV in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 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 other than the MI element, such as an electromagnetic induction type fluxgate sensor element that uses a magnetic wire as a core, or a magnetic flux response type magnetic flux sensor element.

[0012] The depth of the central recess can be greater than the radius of the magnetic wire. In this case, steps in the base on which the second wiring portion is formed can be effectively suppressed. Therefore, the detection coil can be formed more easily and with higher accuracy.

[0013] The depth of the central recess can be greater than the diameter of the magnetic wire. In this case, it is possible to effectively prevent a step from being generated in the base on which the second wiring portion is formed. Therefore, it is possible to form the detection coil more easily and with higher accuracy.

[0014] The second wiring portion may be formed in a plane parallel to the substrate. In this case, the second wiring portion can be formed with higher accuracy. Note that the "plane parallel to the substrate" means a plane substantially parallel to the upper surface of the substrate, and may include a case where there is a slight inclination or slight unevenness that is unavoidable during manufacturing.

[0015] (Embodiment 1) An embodiment of a magnetic sensor element and a manufacturing method thereof 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, and a detection coil 4. The magnetic wire 3 is disposed on the substrate 2. The detection coil 4 is wound around the outer periphery of the magnetic wire 3 in a spiral shape.

[0016] The detection coil 4 is configured by connecting a plurality of first wiring portions 41 and a plurality of second wiring portions 42 to each other. The first wiring portion 41 is a portion of the detection coil 4 formed on the substrate 2 side. The plurality of first wiring portions 41 are formed in parallel to each other. The second wiring portion 42 is a portion of the detection coil 4 formed on the side of the first wiring portion 41 opposite to the substrate 2. The plurality of second wiring portions 42 are formed in parallel to each other.

[0017] 3, the first wiring portion 41 has a central recess 412 between two connection parts 411 connected to the second wiring portion 42. The magnetic wire 3 is disposed in the central recess 412 of the first wiring portions 41 via an insulating material 51. A thickness t1 of the connection part 411 in the normal direction Z of the substrate 2 is greater than a depth t2 of the central recess 412. The normal direction Z of the substrate 2 is also referred to as the "Z direction" below as appropriate. In addition, for convenience, the side on which the detection coil 4 is provided with respect to the substrate 2 in the Z direction will be described as the upper side.

[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 alumina, a semiconductor wafer such as silicon, etc. The surface of the substrate 2 on which the detection coil 4 etc. are arranged is flat. 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 φ of the magnetic wire 3 may be, for example, 10 to 150 μm. Hereinafter, the longitudinal direction of the magnetic wire 3 is appropriately referred to as the X direction. The direction perpendicular to both the Z direction and the X direction is appropriately referred to as the Y direction.

[0019] As described above, the detection coil 4 has a plurality of first wiring portions 41 and a plurality of second wiring portions 42. The first wiring portions 41 are formed on the surface of the substrate 2. The arrangement direction of the plurality of first wiring portions 41 is along the X direction, and the arrangement direction of the plurality of second wiring portions 42 is also the X direction.

[0020] As described above, the first wiring portion 41 has a central recess 412 formed between the two connection portions 411. The central recess 412 penetrates the first wiring portion 41 in the X direction. The bottom of the central recess 412 is formed in a concave curved shape. However, the shape of the central recess 412 is not particularly limited. The thickness of the first wiring portion 41 in the Z direction, that is, the thickness t1 of the connection portion 411, can be, for example, 15 to 200 μm. Of the two connection portions 411, the one on one side in the Y direction is referred to as the first connection portion 411a, and the one on the other side is referred to as the second connection portion 411b.

[0021] The depth t2 of the central recess 412 is preferably larger than the radius φ / 2 of the magnetic wire 3, and more preferably larger than the diameter φ of the magnetic wire 3. In this embodiment, the depth t2 of the central recess 412 is larger than the diameter φ of the magnetic wire 3. This allows the magnetic wire 3 to be housed inside the central recess 412 in the Z direction together with the insulating material 51, as shown in Figures 2 and 3. In other words, it is possible to prevent the magnetic wire 3 from protruding above the opening end of the central recess 412 in the Z direction. In this embodiment, the upper end of the magnetic wire 3 is arranged below the opening end of the central recess 412.

[0022] Accordingly, the second wiring portion 42 can be formed so as not to have a step in the Z direction. That is, in this embodiment, the second wiring portion 42 is formed in a plane parallel to the substrate 2. The second wiring portion 42 is formed so as to connect the first connection portion 411a and the second connection portion 411b of the adjacent first wiring portion 41. The second wiring portion 42 is made of a thin film conductor having a thickness of, for example, about 10 to 120 μm.

[0023] The insulating material 51 disposed in the central recess 412 is interposed between the magnetic wire 3 and the detection coil 4 to ensure electrical insulation between them. In addition to the central recess 412, the insulating material 51 is also formed between and around the multiple first wiring portions 41. The insulating material 51 is made of a resin material such as epoxy or phenol resin.

[0024] 1, a coil terminal 111 electrically connected to both ends of the detection coil 4 and a wire terminal 112 electrically connected to both ends of the magnetic wire 3 are provided on the substrate 2. The coil terminal 111 and the wire terminal 112 are exposed from the insulating material 51. In this embodiment, as shown in FIG. 3, the coil terminal 111 and the wire terminal 112 are provided on the upper surface of the insulating material 51. The coil terminal 111 and the wire terminal 112 are provided at a height position approximately equal to that of the second wiring portion 42 in the Z direction. In FIG. 3, the portion indicated by reference symbol 111a is a lead-out wiring led out from the detection coil 4.

[0025] 2, the thickness d1 of the first wiring portion 41 in the X direction can be, for example, about 3.5 to 20 μm. From the viewpoint of obtaining a high winding density of the detection coil 4, the thickness d1 is preferably 20 μm or less, and from the viewpoint of ensuring ease of manufacture, the thickness d1 is preferably 3.5 μm or more. From the viewpoints of the winding density and ease of manufacture of the detection coil 4, it is preferable that 0.8≦t1 / d1≦4.4, and more preferably that 0.9≦t1 / d1≦3.0.

[0026] In manufacturing the magnetic sensor element 1 of this embodiment, a plurality of thick film conductors 410 are formed in parallel to one another on the substrate 2 as shown in Fig. 4. Then, a central recess 412 is formed in each of the plurality of thick film conductors 410 as shown in Figs. 5 to 7, thereby forming a plurality of first wiring portions 41. The thickness of the thick film conductors 410 is greater than the thickness of the second wiring portion 42. The thickness of the thick film conductors 410 is preferably greater than, for example, the radius φ / 2 of the magnetic wire 3, and more preferably greater than the diameter φ of the magnetic wire 3.

[0027] Next, an example of a method for manufacturing the magnetic sensor element 1 of this embodiment will be specifically described with reference to FIGS.

[0028] First, as shown in Figures 4(a), (b) and (c), a plurality of first wiring parts 41 are formed on the substrate 2 by photolithography. That is, first, a conductive seed layer 43 is formed on the surface of the substrate 2 by sputtering. Then, a photosensitive plating resist 121 is applied to the surface of the seed layer 43, exposed to light and developed to form a plating resist pattern. Then, a thick film conductor part 410 is formed by electrolytic plating. The seed layer 43 and the thick film conductor part 410 may be made of, for example, copper.

[0029] 5(a), (b), and (c), an etching resist 122 is patterned on the thick film conductor 410 and the plating resist 121. That is, a photosensitive etching resist 122 is applied, exposed, and developed to form a desired resist pattern. The pattern of the etching resist 122 is formed so as to expose a portion of the thick film conductor 410 where the central recess 412 is to be provided, and to cover a portion that is to become the connection portion 411. It is preferable that the developing medium for the etching resist 122 and the plating resist 121 are different from each other.

[0030] 6(a), (b), and (c), a central recess 412 is formed in the thick film conductor portion 410 by etching. Here, the etching rate, etching time, and the like are adjusted so that the etching does not reach the entire thick film conductor portion 410 in the Z direction. In this way, a first wiring portion 41 having a central recess 412 is formed.

[0031] Next, as shown in FIGS. 7(a), (b) and (c), the etching resist 122 and the plating resist 121 are stripped, and the exposed seed layer 43 is removed by etching.

[0032] Next, as shown in Figs. 8(a), (b), and (c), an insulating material 511 is formed in the central recess 412 of the first wiring portion 41 and in a portion continuous therewith in the X direction. That is, the insulating material 51 disposed below the magnetic wire 3 is formed. In forming the insulating material 511, first, a photosensitive insulating material 511 is applied to the entire surface of the substrate 2 on which the first wiring portion 41 is formed as shown in Figs. 7(a), (b), and (c), and then the insulating material 511 is exposed to light and developed to form a pattern of the insulating material 511 at the position shown in Figs. 8(a), (b), and (c). The insulating material 511 can also be formed by dry film formation (e.g., sputtering, PVD, CVD, etc.).

[0033] 9(a), (b), and (c), the magnetic wire 3 is disposed so as to span the central recesses 412 of the multiple first wiring parts 41. After that, an insulating material 512 is formed in the multiple central recesses 412 and in areas continuous therewith in the X-direction so as to cover the magnetic wire 3.

[0034] 10(a), (b), and (c), insulating material 513 is formed on the surface of substrate 2 in areas other than the multiple central recesses 412 and areas continuous therewith in the X-direction. The upper surfaces of insulating material 512 and insulating material 513 are formed to be flush with the upper surface of connection portion 411 of first wiring portion 41. The insulating materials 511, 512, and 513 may be the same type of insulating material, such as epoxy resin.

[0035] 11(a), (b), and (c), a plurality of second wiring parts 42 are formed on the upper surfaces of the plurality of first wiring parts 41 and the insulating material 512. The second wiring parts 42 can also be formed by photolithography. That is, the plurality of second wiring parts 42 are patterned by sputtering, forming a plating resist, plating, etching, or the like.

[0036] In this manner, the magnetic sensor element 1 shown in Fig. 1 to Fig. 3 can be manufactured. Note that in Fig. 4 to Fig. 11 and the description of the manufacturing method above, the coil terminal 111, the wire terminal 112, etc. and the manufacturing method thereof are omitted. Also, the above-mentioned insulating materials 511, 512, and 513 become the insulating material 51 shown in Fig. 1 to Fig. 3.

[0037] Next, the effects of this embodiment will be described. In the magnetic sensor element 1, the first wiring portion 41 is provided with a central recess 412. The magnetic wire 3 is disposed in the central recess 412 of the plurality of first wiring portions 41 via the insulating material 51. Therefore, there is no need to provide a step on the surface of the substrate 2 on which the first wiring portion 41 is formed, and the first wiring portion 41 can be easily formed with high accuracy. In addition, since the magnetic wire 3 is disposed in the central recess 412 of the first wiring portion 41, the base on which the second wiring portion 42 is formed can also suppress steps. As a result, the detection coil 4 can be easily formed.

[0038] Moreover, the depth t2 of the central recess 412 is larger than the diameter φ of the magnetic wire 3. This effectively prevents steps from being generated in the base on which the second wiring portion 42 is formed. This makes it possible to form the detection coil 4 more easily and with higher accuracy.

[0039] Moreover, the second wiring portion 42 is formed in a plane parallel to the substrate 2. Therefore, the second wiring portion can be formed with higher accuracy.

[0040] As described above, according to the present embodiment, it is possible to provide a magnetic sensor element capable of easily forming a detection coil, and a manufacturing method thereof.

[0041] (Embodiment 2) In this embodiment, as shown in FIG. 12, the depth t2 of the central recess 412 is smaller than the diameter φ of the magnetic wire 3. In the embodiment shown in FIG.

[0042] In this embodiment, the magnetic wire 3 protrudes from the open end of the central recess 412. Therefore, the second wiring portion 42 is not flat, but has a shape having a step in the Z direction. However, since the first wiring portion 41 has the central recess 412, the step of the second wiring portion 42 can be reduced. Therefore, in this embodiment, the second wiring portion 42 can be easily formed with high accuracy.

[0043] The rest of the configuration and the effects are the same as those of embodiment 1. Note that, among the symbols used in embodiment 2 and the following embodiments, the same symbols as those used in the previous embodiments represent the same components, etc. as those in the previous embodiments, unless otherwise specified.

[0044] (Embodiment 3) In this embodiment, as shown in FIGS. 13 and 14, a coil terminal 111 and a wire terminal 112 are provided at a position closer to the substrate 2 than the second wiring portion 42 is. In embodiment 1 (see Figures 1 and 3), the coil terminal 111 and the wire terminal 112 are shown provided on the upper surface of the insulating material 51, but in this embodiment, the coil terminal 111 and the wire terminal 112 are provided on the upper surface of the substrate 2 without any insulating material therebetween. The rest of the configuration and effects are the same as those of the first embodiment.

[0045] 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]

[0046] 1. Magnetic sensor element 2. Board 3 Magnetic Wire 4 Detection coil 41 1st wiring section 410 Thick film conductor 411 Connection Part 412 Central recess 42 2nd wiring section 51 Insulation materials

Claims

1. A magnetic sensor element comprising a substrate, a magnetic wire disposed on the substrate, and a detection coil spirally disposed around the magnetic wire, the detection coil is configured by connecting a plurality of first wiring parts formed in parallel to each other on the substrate side and a plurality of second wiring parts formed in parallel to each other on the opposite side of the first wiring parts from the substrate, the first wiring portion has a central recess between two connection sites connected to the second wiring portion, the magnetic wire is disposed in the central recess of the first wiring portion via an insulating material; A magnetic sensor element, wherein a thickness of the connection portion in a normal direction of the substrate is greater than a depth of the central recess.

2. The magnetic sensor element according to claim 1 , wherein the depth of the central recess is greater than the diameter of the magnetic wire.

3. The magnetic sensor element according to claim 2 , wherein the second wiring portion is formed in a plane parallel to the substrate.

4. A method for manufacturing a magnetic sensor element according to any one of claims 1 to 3, comprising the steps of: forming a plurality of thick-film conductor portions in parallel with each other on a surface of the substrate; A method for manufacturing a magnetic sensor element, comprising forming a plurality of the first wiring portions by forming the central recess in each of the plurality of thick film conductor portions.

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