Magnetic sensor element manufacturing method

Abstract

To provide a magnetic sensor element manufacturing method with which it is possible to form an insulator with high accuracy.SOLUTION: Provided is a method for manufacturing a magnetic sensor element 1 comprising a substrate 2, a magnetic wire 3, a detection coil 4, and an insulator 5. The method includes: a first wiring step for forming a plurality of first wirings 41 in parallel to each other on the substrate 2; a first insulating step for forming a first insulator 51 on the substrate 2 on which the plurality of first wirings 41 have been formed; a wire arrangement step for arranging a magnetic wire 3 on the surface of the first insulator 51; a second insulating step for forming a second insulator 52 so as to cover a section of the magnetic wire 3 that is not in contact with the first insulator 51; and a second wiring step for forming a plurality of second wirings 42 on the outer circumferential surface of the second insulator 52. At least one of the first insulating step and the second insulating step uses a nano-imprint method.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a magnetic sensor element.

Background Art

[0002] As a magnetic sensor element, a magneto-impedance element including a substrate, an amorphous wire (i.e., a magnetic wire) disposed on the substrate, and a detection coil spirally provided via an insulator on the outer periphery of the magnetic wire, and a method for manufacturing the same are disclosed in Patent Document 1.

[0003] The magnetic sensor element disclosed in Patent Document 1 forms a detection coil by integrating a planar pattern and a three-dimensional pattern. That is, the detection coil is formed by a planar pattern formed on the substrate surface and a three-dimensional pattern formed across the outer surface of the insulator and the surface of the planar pattern and arranged so as to cross the magnetic wire. In this way, the insulator is formed three-dimensionally so as to enclose the magnetic wire.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, depending on the required performance of the magnetic sensor element, it may be difficult to form the insulator with sufficient accuracy. If the shape, dimensions, etc. of the insulator interposed between the magnetic wire and the detection coil deviate from the desired shape, dimensions, etc., the shape, etc. of the detection coil formed on the outer surface of the insulator will also deviate from the desired shape, etc. Then, depending on the required magnetic sensor element, there is a concern that it may be difficult to obtain the required output characteristics. Thus, in view of the performance of the magnetic sensor element, forming the insulator with high precision may be required as an important issue.

[0006] The present invention has been made in view of such problems, and aims to provide a method for manufacturing a magnetic sensor element capable of forming an insulator with high precision.

Means for Solving the Problems

[0007] One aspect of the present invention is a method for manufacturing a magnetic sensor element including a substrate, a magnetic wire disposed on the substrate, a detection coil formed of a thin film conductor spirally provided on the outer periphery of the magnetic wire, and an insulator interposed between the magnetic wire and the detection coil, comprising: a first wiring step of forming a plurality of first wiring portions, which are part of the detection coil, in parallel with each other on the substrate; a first insulation step of forming a first insulator, which is part of the insulator, on the substrate on which the plurality of first wiring portions are formed; a wire placement step of placing the magnetic wire on the surface of the first insulator; a second insulation step of forming a second insulator, which is another part of the insulator, so as to cover a portion of the magnetic wire that is not in contact with the first insulator; a second wiring step of forming a plurality of second wiring portions, which constitute another part of the detection coil, on the outer peripheral surface of the second insulator; and at least one of the first insulation step and the second insulation step uses a nanoimprint method in the method for manufacturing a magnetic sensor element.

Effects of the Invention

[0008] In the method for manufacturing the magnetic sensor element, at least one of the first insulation step and the second insulation step uses a nanoimprint method. Thereby, the formation accuracy of at least one of the first insulator and the second insulator can be improved. As a result, the insulator can be formed with high precision.

[0009] As described above, according to the above aspect, a method for manufacturing a magnetic sensor element capable of forming an insulator with high precision can be provided.

Brief Description of the Drawings

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Embodiments for Carrying Out the Invention

[0011] The magnetic sensor element can be, for example, a magneto-impedance element (hereinafter also referred to as an MI element) that utilizes the magneto-impedance effect. However, the magnetic sensor element can also be other than an MI element, such as an electromagnetic induction type fluxgate sensor element using a magnetic wire as a core or a magnetic flux response type magnetic flux sensor element.

[0012] In the second insulation process, the second insulator can be formed using a nanoimprint method. In this case, the molding accuracy of the second insulator, which is relatively difficult to form accurately, can be improved. Therefore, the molding accuracy of the insulator can be effectively improved.

[0013] Further, the method for manufacturing the magnetic sensor element includes a groove forming step of forming a groove portion having an inner wall surface with a concave curved surface on the substrate before the first wiring step, In the first wiring step, a plurality of the first wiring portions are formed on the inner wall surface of the groove portion, In the first insulation step, a plurality of the first insulators are formed on the inner wall surface of the groove portion, In the wire arrangement step, the magnetic wire can be arranged in the groove portion. In this case, the protruding height of the magnetic wire from the substrate surface can be reduced. Therefore, the molding of the second insulator can be facilitated.

[0014] Further, the first wiring portion and the second wiring portion can be formed so as to be smoothly connected. In this case, at the joint between the first wiring portion and the second wiring portion in the detection coil, the formation of an edge can be prevented. As a result, the generation of noise can be suppressed.

[0015] Also, the insulator interposed between the magnetic wire and the detection coil can be formed to have a film thickness equal to or less than the film thickness of the detection coil over the entire circumference. In this case, the detection coil can be brought closer to the magnetic wire, and a high-output magnetic sensor element can be obtained.

[0016] Further, the magnetic wire can have a circular cross-sectional shape orthogonal to the longitudinal direction, and the groove portion can have a semi-circular cross-sectional shape orthogonal to the longitudinal direction. In this case, the generation of noise can be more effectively prevented, and a magnetic sensor element with more excellent output characteristics can be obtained.

[0017] In the groove forming step, the groove portion can be formed using a nanoimprint method. In this case, the groove portion can be formed with high precision. Along with this, the formation accuracy of the first insulator and the first wiring portion can be improved.

[0018] Further, in the first insulation process, the first insulator may be formed using a nanoimprint method. In this case, the first insulator can be formed with high precision.

[0019] (Embodiment 1) An embodiment of a method for manufacturing a magnetic sensor element will be described with reference to FIGS. 1 to 9. A magnetic sensor element 1 manufactured by the manufacturing method of this embodiment includes a substrate 2, a magnetic wire 3, a detection coil 4, and an insulator 5, as shown in FIGS. 1 to 3. The magnetic wire 3 is disposed on the substrate 2. The detection coil 4 is composed of a thin film conductor spirally provided on the outer periphery of the magnetic wire 3. The insulator 5 is interposed between the magnetic wire 3 and the detection coil 4.

[0020] The manufacturing method of the magnetic sensor element of this embodiment includes the following first wiring process, first insulation process, wire arrangement process, second insulation process, and second wiring process. The first wiring process is a process of forming a plurality of first wiring portions 41 that are part of the detection coil 4 in parallel on the substrate 2 (see step S3 in FIGS. 3 and 4). The first insulation process is a process of forming a first insulator 51 that is part of the insulator 5 on the substrate 2 on which the plurality of first wiring portions 41 are formed (see step S4 in FIG. 4). The wire arrangement process is a process of arranging the magnetic wire 3 on the surface of the first insulator 51 (see step S5 in FIG. 5). The second insulation process is a process of forming a second insulator 52 that is another part of the insulator 5 so as to cover a portion of the magnetic wire 3 that is not in contact with the first insulator 51 (see step S6 in FIG. 5). The second wiring process is a process of forming a plurality of second wiring portions 42 that constitute the other part of the detection coil 4 on the outer peripheral surface of the second insulator 52 (see step S7 in FIG. 5).

[0021] And at least one of the first insulation process and the second insulation process uses a nanoimprint method.

[0022] In this embodiment, particularly in the second insulation process, the second insulator 52 is formed using a nanoimprint method. Details of the second insulation process will be described later (see FIGS. 6 and 7).

[0023] Also, the method for manufacturing the magnetic sensor element of this embodiment includes a groove forming process of forming a groove portion 23 having a concave curved inner wall surface on the substrate 2 before the first wiring process (see step S2 in FIG. 4). In this case, in the first wiring process, a plurality of first wiring portions 41 are formed on the inner wall surface of the groove portion 23 (see step S3 in FIG. 4). In the first insulation process, a first insulator 51 is formed on the inner wall surface of the groove portion 23 (see step S4 in FIG. 4). In the wire arrangement process, the magnetic wire 3 is arranged in the groove portion 23 (see step S5 in FIG. 5).

[0024] The first wiring portion 41 and the second wiring portion 42 are formed so as to be smoothly connected (see step S7 in FIG. 4). Here, the state in which the first wiring portion 41 and the second wiring portion 42 are smoothly connected is a state in which both wiring portions are continuously connected linearly or curvilinearly at their connection portion, and the connection portion does not form a corner portion.

[0025] As shown in FIG. 2, the insulator 5 interposed between the magnetic wire 3 and the detection coil 4 is formed to have a film thickness equal to or less than the film thickness of the detection coil over the entire circumference.

[0026] The magnetic wire 3 has a circular cross-sectional shape perpendicular to the longitudinal direction, and the groove portion 23 has a semi-circular cross-sectional shape perpendicular to the longitudinal direction.

[0027] The magnetic sensor element 1 thus obtained is configured in a state where the magnetic wire 3 around which the detection coil 4 is wound is arranged in the groove portion 23 formed in the substrate 2, as shown in FIGS. 1 and 2.

[0028] In this embodiment, the magnetic sensor element 1 is a MI element. Hereinafter, the longitudinal direction of the magnetic wire 3 is appropriately referred to as the X direction. Also, the normal direction of the substrate 2 is appropriately referred to as the Z direction. The direction orthogonal to both the Z direction and the X direction is appropriately referred to as the Y direction. Also, in the Z direction, the side where the detection coil 4 is provided with respect to the substrate 2 will be described for convenience as the upper side.

[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. As the substrate body 21, for example, a ceramic substrate such as alumina, a semiconductor wafer such as silicon, or the like can be used.

[0030] The magnetic wire 3 is an amorphous wire, and the cross-sectional shape orthogonal to the longitudinal direction (X direction) can be a wire having a substantially circular shape. In this embodiment, the magnetic wire 3 has a circular cross-sectional shape orthogonal to the X direction. Accordingly, the groove portion 23 has a semi-circular cross-sectional shape orthogonal to the X direction. The diameter of the magnetic wire 3 can be, for example, 1 to 50 μm.

[0031] The detection coil 4 is made of, for example, a thin film conductor having a thickness of about 1 to 10 μm. That is, the plurality of first wiring portions 41 and the plurality of second wiring portions 42 are each made of a thin film conductor.

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

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

[0034] Next, an example of the manufacturing method of the magnetic sensor element 1 of the present embodiment will be specifically described with reference to FIGS. 4 to 6. First, as shown in step S1 of FIG. 4, a resin layer 22 is formed on the upper surface of the substrate body 21. Next, as shown in step 2, a groove portion 23 is formed in the resin layer 22 (groove forming step). The groove portion 23 is formed so that the cross-sectional shape orthogonal to the X direction is substantially semi-circular.

[0035] The shape and size of the groove portion 23 are appropriately designed according to the shape and diameter of the magnetic wire 3. In the present embodiment, since the shape of the cross-section of the magnetic wire 3 orthogonal to the X direction is substantially a perfect circle, the shape of the cross-section of the groove portion 23 orthogonal to the X direction is semi-circular. Further, the radius of curvature of the semi-circular shape of the groove portion 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 portion 23 be substantially equal to the sum of the thickness of the detection coil 4 and the thickness of the insulator 5 more than the radius of the magnetic wire 3.

[0036] The formation of the groove portion 23 can be performed, for example, using the nanoimprint technology (see FIG. 9) described later. By using the nanoimprint technology, the groove portion 23 can be formed in the above-described desirable dimensions and shape.

[0037] Next, as shown in step S3 of FIG. 4, a first wiring portion 41 is formed on the inner wall surface of the groove portion 23 (first wiring step). The formation of the first wiring portion 41 is performed by pattern formation using photolithography. That is, a plurality of first wiring portions 41 are formed by sputtering, forming a plating resist, plating, etching, and the like. The plurality of first wiring portions 41 are arranged in parallel in the X direction as shown in FIG. 3.

[0038] Next, as shown in step S4 of FIG. 4, a first insulator 51 is formed on the inner wall surface of the groove portion 23 so as to cover the plurality of first wiring portions 41 (first insulation step). The first insulator 51 constitutes a part of the above-described insulator 5. The thickness of the first insulator 51 covering the first wiring portion 41 is smaller than the thickness of the first wiring portion 41.

[0039] Next, as shown in step S5 of FIG. 5, the magnetic wire 3 is placed on the first insulator 51 (wire placement step). That is, the magnetic wire 3 is disposed in the groove portion 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 will be disposed within the groove portion 23. The outer peripheral surface of the magnetic wire 3 is in close contact with the first insulator 51.

[0040] Next, as shown in step S6 of FIG. 5, a second insulator 52 is formed on the upper approximately half of the outer peripheral surface of the magnetic wire 3 (second insulation step). The second insulator 52 constitutes a part of the above-described insulator 5. The second insulator 52 smoothly connects with the first insulator 51 to form the insulator 5 that covers the entire circumference of the magnetic wire 3. The formation of the second insulator 52 is performed using a nanoimprint method (see FIGS. 6 and 7) described later.

[0041] 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) (second wiring step). Similar to the first wiring portion 41, the plurality of second wiring portions 42 can be pattern-formed using photolithography. The plurality of second wiring portions 42 smoothly connect with the plurality of first wiring portions 41 to form the spiral detection coil 4.

[0042] For the formation of the second insulator 52 in the above-described step S6 (second insulation step), a nanoimprint method is used. Specific examples of the method for forming the second insulator 52 by the nanoimprint method are shown in FIGS. 6 and 7.

[0043] As shown in steps S61 and S62 of FIG. 6, an insulating resin 520 that becomes the second insulator 52 is applied to the upper surface of the substrate 2 on which the magnetic wire 3 is disposed. This insulating resin 520 is made of a photocurable resin. This insulating resin 520 is formed on the substrate 2 to a thickness such that the magnetic wire 3 is sufficiently buried.

[0044] Thereafter, as shown in step S63 of FIG. 6 and step S64 of FIG. 7, a mold 60 is pressed against the upper surface of the insulating resin 520, and irradiation light (specifically, ultraviolet light) that passes through the mold 6 is irradiated onto the insulating resin 520.

[0045] The mold 60 is made of a material that is transparent to the ultraviolet light irradiated onto the insulating resin 520, such as quartz, for example. The mold 60 has a concave curved surface-shaped concave mold surface 62 as shown in FIG. 8. The concave mold surface 62 has a semi-cylindrical shape along the outer shape of the magnetic wire 3. The radius of curvature of the concave mold surface 62 is larger than the radius of the magnetic wire 3 by the thickness of the insulator 5.

[0046] As a result, as shown in step S64 of FIG. 7, when the mold 60 is pressed against the substrate 2, the insulating resin 520 is molded between the concave mold surface 62 and the outer peripheral surface of the magnetic wire 3. That is, the shape of the concave mold surface 62 is transferred to the insulating resin 520, and the insulating resin 520 is molded into a predetermined shape.

[0047] As shown in FIG. 8, the mold 60 has flat surfaces on both sides of the concave mold surface 62. The flat surfaces face the upper surface of the substrate 2 where the groove portion 23 is not formed. The mold 60 is provided with a light-shielding layer 63 that blocks the irradiation light on the flat surfaces. As a result, as shown in step S64 of FIG. 7, during exposure, while the portion of the insulating resin 520 disposed on the outer peripheral surface of the magnetic wire 3 is exposed and photocured, the portions applied to the upper surface of the substrate 2 on both sides of the groove portion 23 are not exposed and do not photocure.

[0048] Next, as shown in step S65 of FIG. 7, after releasing the substrate 2 from the mold 60, the exposed portion of the insulating resin 520 is left as the second insulator 52 by developing the insulating resin 520. As a result, as shown in step S66 of FIG. 7, the second insulator 52 is formed in a desired shape along the outer peripheral surface of the magnetic wire 3.

[0049] Also, in the groove forming step in steps S1 to S2 described above, as shown in FIG. 9, the nanoimprint method can be used. In this case, as the resin layer 22 applied in step S1 described above, for example, a thermoplastic resin, a thermosetting resin, or a photocurable resin is used. That is, when thermal nanoimprint is used, a thermoplastic resin or a thermosetting resin is used as the resin layer 22. When photo nanoimprint is used, a photocurable resin is used as the resin layer 22.

[0050] In forming the groove portion 23 by the nanoimprint method, as shown in FIG. 9, a mold 6 having a mold surface 61 for forming the groove portion 23 is used.

[0051] When thermal nanoimprint is used, 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. Then, after cooling the substrate 2, it is 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 to form the groove portion 23.

[0052] When photo nanoimprint is used, 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 rays. Therefore, as the mold 6, one that is transparent to the irradiated ultraviolet rays is used. 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 to form the groove portion 23.

[0053] Note that the first insulation process (step S4) can be formed using photolithography. However, the nanoimprint method can also be used in the first insulation process. The case of using the nanoimprint method in the first insulation process will be described later.

[0054] Next, the operation and effect of this embodiment will be described. In the method for manufacturing the magnetic sensor element, the nanoimprint method is used in the second insulation process. Thereby, the formation accuracy of the second insulator 52 can be improved. As a result, the insulator 5 can be formed with high precision.

[0055] When the second insulator 52 is formed using general photolithography as shown in FIGS. 10 and 11 without using the nanoimprint method, there is a limit to the formation accuracy. An example of a method for forming the second insulator 52 by general photolithography is shown below.

[0056] As shown in step T1 of FIG. 10, a photocurable insulating resin 520 that will become the second insulator 52 is applied to the substrate 2 on which the magnetic wire 3 is disposed. Then, the resin is exposed through a photomask 70 provided with a mask pattern 73 (step T2). As a result, the insulating resin 520 under the mask pattern 73, that is, the insulating resin 520 around the magnetic wire 3, is exposed to light. Next, by developing, only the insulating resin 520 around the magnetic wire 3 remains as shown in step T63 of FIG. 11. Before the insulating resin 520 is cured by heat treatment thereafter, the insulating resin 520 deforms so as to follow the outer peripheral surface of the magnetic wire 3 (step T64 in FIG. 11). However, although the insulating resin 520 follows the outer peripheral surface of the magnetic wire 3 to some extent, the way of following varies depending on, for example, the type and state of the insulating resin 520. Therefore, it is difficult to control the outer shape of the obtained second insulator 52 with high precision.

[0057] Thus, it is difficult to accurately form the second insulator 52 into a desired shape. For example, even if an attempt is made to form the second insulator 52 in a semi-circular cross-sectional shape along the outer peripheral surface of the magnetic wire 3, it is difficult to adjust it to such a shape. In this case, for example, there is a concern that the thickness of the second insulator 52 (the distance from the outer peripheral surface of the magnetic wire 3 to the outer surface of the second insulator 52) varies depending on the position or deviates too much from the target thickness.

[0058] Then, as shown in step T7 of FIG. 11, variations also occur in the shape, the distance from the magnetic wire 3, etc. of the second wiring portion 42 formed outside the second insulator 52. As a result, it can be a factor that makes it difficult to obtain desired sensor characteristics.

[0059] Furthermore, if the thickness dimension accuracy of the second insulator 52 is too low, there is also a concern that it may lead to a defective formation of the second wiring portion 42. That is, if the thickness dimension of the second wiring portion 42 is too low, when forming the second wiring portion 42 by photolithography, there is a concern that the focal position of the irradiation light deviates from an appropriate position with respect to the plating resist during exposure of the plating resist. In this case, there is also a concern that it may lead to a patterning defect.

[0060] On the other hand, in the manufacturing method of the magnetic sensor element of the present embodiment, as described above, the second insulator 52 is formed using the nanoimprint method. Thereby, the second insulator 52 can be formed with high precision. As a result, it becomes easier to obtain the magnetic sensor element 1 having desired sensor characteristics.

[0061] Also, in the present embodiment, particularly in the second insulation step, the nanoimprint method is used. Thereby, the molding accuracy of the second insulator 52, which is relatively difficult to form accurately, can be improved. Therefore, the molding accuracy of the insulator 5 can be effectively improved.

[0062] Further, the method for manufacturing the magnetic sensor element of this embodiment includes a groove forming step. Thereby, the protruding height of the magnetic wire 3 from the surface of the substrate 2 can be reduced. Therefore, the molding of the second insulator 52 can be facilitated.

[0063] Further, the first wiring portion 41 and the second wiring portion 42 are formed so as to be smoothly connected. Thereby, it is possible to prevent an edge from being formed at the joint between the first wiring portion 41 and the second wiring portion 42 in the detection coil 4. As a result, the generation of noise can be suppressed.

[0064] For example, when forming the detection coil 94 by providing a thin film conductor pattern on the inner wall surface of a groove portion 923 having a rectangular cross section as in the magnetic sensor element 9 shown in FIG. 12, an edge E is formed in the detection coil 94. To obtain this magnetic sensor element 9, a groove portion 923 having a rectangular cross section is formed in the substrate 92. A thin film conductor pattern 941 is formed on the inner wall surface of this groove portion 923, and a magnetic wire 93 is disposed in the groove portion 923 and filled with an embedded insulator 95. A thin film conductor pattern 942 is formed on the upper surface of this embedded insulator 95. The detection coil 94 is formed by connecting the thin film conductor pattern 941 and the thin film conductor pattern 942.

[0065] In the case of such a magnetic sensor element 9, an edge is formed at the location indicated by the symbol E in the detection coil 94. This edge E is likely to be a cause of noise. In the magnetic sensor element 1 of this embodiment, the formation of such an edge in the detection coil 4 can be prevented as described above.

[0066] Further, the insulator 5 interposed between the magnetic wire 3 and the detection coil 4 is formed to have a film thickness equal to or less than the film thickness of the detection coil 4 over the entire circumference. Thereby, the detection coil 4 can be brought closer to the magnetic wire 3, and a high-output magnetic sensor element can be obtained.

[0067] In addition, the magnetic wire 3 has a circular cross-sectional shape perpendicular to the longitudinal direction, and the groove portion 23 has a semi-circular cross-sectional shape perpendicular to the longitudinal direction. Thereby, the generation of noise can be more effectively prevented, and the magnetic sensor element 1 with more excellent output characteristics can be obtained.

[0068] Also, in the case of this embodiment, even in the groove forming step, the groove portion 23 is formed using the nanoimprint method. Thereby, the groove portion 23 can be formed with high precision. Along with this, the forming precision of the first insulator 51 and the first wiring portion 41 can be improved. As a result, the precision of the insulator 5 and the detection coil 4 can be further improved.

[0069] As described above, according to this embodiment, a method for manufacturing a magnetic sensor element capable of forming an insulator with high precision can be provided.

[0070] (Embodiment 2) This embodiment is a method for manufacturing a magnetic sensor element that uses the nanoimprint method also in the first insulation step, as shown in FIGS. 13 and 14.

[0071] An example of the manufacturing method of this embodiment will be described with reference to the drawings. Up to the first wiring step, the groove portion 23 and the first wiring portion 41 can be formed on the substrate 2 by the same method as in Embodiment 1. From this state, an insulating resin 510 that becomes the first insulator 51 is disposed in the groove portion 23. This insulating resin 510 can be a photocurable resin.

[0072] Thereafter, as shown in step S42, a mold 600 is pressed against the upper surface of the insulating resin 510, and irradiation light (specifically, ultraviolet rays) that passes through the mold 600 is irradiated onto the insulating resin 510.

[0073] The mold 600 is made of a material that is transparent to the ultraviolet rays irradiated on the insulating resin 510. The mold 600 has a convex surface-shaped convex mold surface 604. The convex mold surface 604 has a semi-cylindrical shape along the inner wall surface of the groove portion 23. The radius of curvature of the convex mold surface 604 is larger than the radius of the groove portion 23 by an amount equal to the sum of the thickness of the detection coil 4 and the thickness of the insulator 5.

[0074] As a result, as shown in step S43 of FIG. 14, when the mold 600 is pressed against the substrate 2, the insulating resin 510 is molded between the convex mold surface 604 and the first wiring portion 41 on the inner wall surface of the groove portion 23. That is, the shape of the convex mold surface 604 is transferred to the insulating resin 510, and the insulating resin 510 is molded into a predetermined shape.

[0075] The mold 600 has flat surfaces on both sides of the concave mold surface 602. The flat surfaces face the upper surface of the substrate 2 where the groove portion 23 is not formed. A light-shielding layer 603 that blocks the irradiated light is provided on the flat surface of the mold 600. As a result, during exposure, while the portion of the insulating resin 510 disposed in the groove portion 23 is exposed and photocured, the portions applied to the upper surface of the substrate 2 on both sides of the groove portion 23 are not exposed and do not photocure.

[0076] Next, as shown in step S44 of FIG. 14, after the substrate 2 is released from the mold 600, the insulating resin 510 is developed, and the exposed portion of the insulating resin 510 remains as the first insulator 51. As a result, the first insulator 51 is formed in a desired shape along the outer peripheral surface of the magnetic wire 3.

[0077] The rest is the same as in the first embodiment. Among the reference numerals used in the second and subsequent embodiments, those that are the same as the reference numerals used in the previous embodiments represent the same components and the like as those in the previous embodiments unless otherwise specified.

[0078] In the case of this embodiment, the first insulator 51 can be formed with high precision. And in both the first insulation step and the second insulation step, by using the nanoimprint method, the insulator 5 can be formed with higher precision. In addition, it has the same effects as those in Embodiment 1.

[0079] (Embodiment 3) In this embodiment, as shown in FIG. 15, when forming the groove portion 23 in the substrate 2, an isotropic etching is used. That is, an etching resist 71 is provided on the surface of the substrate 2, and an opening 711 narrower in width than the groove portion 23 to be obtained is provided in the etching resist 71. In this state, a part of the substrate 2 is isotropically etched.

[0080] In this embodiment, as the substrate 2, single-crystalline silicon (Si) provided with a silicon oxide (SiO2) film 24 is used.

[0081] An etching resist 71 is provided on the upper surface of such a substrate 2, and a pattern of the opening 711 is formed in a part of the etching resist according to the position and range of the groove portion 23 to be obtained. In this state, the substrate 2 is etched with an etching solution composed of a mixed solution of hydrofluoric acid (HF) and nitric acid (HNO3). Thereby, the substrate 2 made of single-crystalline silicon is isotropically etched. The isotropic etching proceeds not only in the thickness direction (Z direction) of the substrate 2 but also in the Y direction from the opening 711 of the etching resist 71.

[0082] By adjusting the mixing ratio of hydrofluoric acid and nitric acid in the etching solution, the shape of the etched portion can be adjusted. Generally, by increasing the mixing ratio of nitric acid, it is easy to increase the radius of curvature of the corner portion. Therefore, by appropriately adjusting the mixing ratio of hydrofluoric acid and nitric acid in the etching solution, the etching time, the temperature of the etching solution, etc., and further, the size of the opening 711 of the etching resist, etc., a groove portion 23 having an appropriate size and shape can be formed.

[0083] Others have the same configuration and effects as those in Embodiment 1.

[0084] (Embodiment 4) This embodiment is a form in which the groove portion 23 of the substrate 2 is formed by using grayscale exposure, as shown in FIG. 16. The substrate 2 is a non-magnetic flat substrate. In this embodiment, similar to Embodiment 1, 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 can be made of, for example, a ceramic substrate such as alumina, a semiconductor wafer such as silicon, or the like.

[0085] That is, first, a photosensitive resin layer 22 is formed on the upper surface of the substrate body 21. In this embodiment, an example in which the resin layer 22 is a positive photosensitive resin is shown. The photosensitive resin layer 22 is irradiated with ultraviolet rays through a photomask 72 to expose the resin layer 22.

[0086] The photomask 72 has a mask pattern 721 corresponding to the groove portion 23. That is, the photomask 72 has a mask pattern 721 that transmits ultraviolet rays at the position where the groove portion 23 is to be formed, and other regions do not transmit ultraviolet rays. The mask pattern 721 has a gradation, and the degree of ultraviolet ray transmission varies depending on the position. Specifically, the mask pattern 721 is configured such that the light transmittance decreases from the central portion in the Y direction toward the outside.

[0087] As a result, as shown in FIG. 16, the ultraviolet rays irradiated onto the resin layer 22 through the photomask 72 are strong at the central portion in the Y direction and become weaker toward the outside. Therefore, in the resin layer 22, the depth at which it is exposed varies depending on the position in the Y direction. As a result, the groove portion 23 formed by performing the development process has different depths depending on the position in the Y direction. That is, the central portion in the Y direction is deep, and the shape becomes shallower toward the outside. By adjusting the way the gradation of the photomask 72 is applied, a groove portion 23 having a desired cross-sectional shape can be obtained. That is, a groove portion 23 having an inner wall surface with a concave curved surface shape such as a substantially semicircular cross-sectional shape can be formed.

[0088] The rest has the same configuration and effects as those of Embodiment 1. In addition, in this embodiment, an example in which the resin layer 22 is a positive photosensitive resin has been shown. However, even when a negative photosensitive resin is used for the resin layer, the groove portion can be formed by substantially the same method.

[0089] (Embodiment 5) As shown in FIGS. 17 to 20, this embodiment is a form of a method for manufacturing a magnetic sensor element 1 in which a magnetic wire 3 and a detection coil 4 are provided on a substrate 2 without providing a groove portion.

[0090] That is, the magnetic sensor element 1 to be obtained by the manufacturing method of this embodiment has a configuration in which a magnetic wire 3 is placed on a flat upper surface of a substrate 2 via a first wiring portion 41 and a first insulator 51, as shown in FIG. 17. The detection coil 4 is constituted by a flat first wiring portion 41 along the upper surface of the substrate 2 and second wiring portions 42 disposed on both sides in the Y direction and on the upper side in the Z direction of the magnetic wire 3. The insulator 5 is constituted by a flat first insulator 51 along the upper surface of the substrate 2 and second insulators 52 disposed on both sides in the Y direction and on the upper side in the Z direction of the magnetic wire 3.

[0091] Next, an example of a method for manufacturing the magnetic sensor element of this embodiment will be described with reference to FIGS. 18 to 20. First, as shown in step S601 of FIG. 18, a magnetic wire 3 is placed on a flat upper surface of a substrate 2 via a first wiring portion 41 and a first insulator 51. Next, as shown in step S602 of FIG. 18, an insulating resin 520 is applied to the upper surface of the substrate 2 so as to cover the first wiring portion 41 and the first insulator 51.

[0092] Next, as shown in steps S603 and S604 of FIG. 19, a mold 6A is pressed against the upper surface of the insulating resin 520, and irradiation light (specifically, ultraviolet light) that passes through the mold 6A is irradiated onto the insulating resin 520.

[0093] The mold 6A has a concave mold surface 62 in the shape of a concave curved surface. The width and depth of the concave mold surface 62 in the Y direction are larger than the diameter of the magnetic wire 3. The shape of the bottom surface of the concave mold surface 62 has a semi-cylindrical shape along the outer shape of the magnetic wire 3. The radius of curvature of the concave mold surface 62 is larger than the radius of the magnetic wire 3 by the thickness of the insulator 5.

[0094] As a result, as shown in step S604 of FIG. 19, when the mold 60 is pressed against the substrate 2, an insulating resin 520 is formed between the concave mold surface 62 and the outer peripheral surface of the magnetic wire 3. That is, the shape of the concave mold surface 62 is transferred to the insulating resin 520, and the insulating resin 520 is molded into a predetermined shape. Similar to the mold 60 shown in Embodiment 1, the mold 6A has a light-shielding layer 63.

[0095] Next, as shown in step S605 of FIG. 20, the substrate 2 is released from the mold 6A. Then, by developing the insulating resin 520, the exposed portion of the insulating resin 520 remains as the second insulator 52. As a result, as shown in step S606 of FIG. 20, the second insulator 52 is formed in a desired shape along the outer peripheral surface of the magnetic wire 3. Other aspects are the same as those in Embodiment 1.

[0096] In the case of this embodiment, the height of the second insulator 52 in the Z direction is larger than the diameter of the magnetic wire 3. From this perspective, it is more difficult to form the second insulator 52 with high precision. Therefore, by using the nanoimprint method in the formation of the second insulator 52, the formation accuracy of the second insulator 52 can be effectively improved. Other than that, it has the same operational effects as those in Embodiment 1.

[0097] (Embodiment 6) This embodiment is a method for manufacturing a magnetic sensor element 1 including a plurality of magnetic wires 3, as shown in FIGS. 21 and 22. The magnetic sensor element 1 obtained by this embodiment includes a substrate 2, a plurality of magnetic wires 3, a detection coil 4 provided spirally on the outer periphery of the plurality of magnetic wires 3, and an insulator 5 interposed between the magnetic wire 3 and the detection coil 4.

[0098] An example of a method for manufacturing the magnetic sensor element of this embodiment will be described with reference to FIGS. 23 to 25. First, as shown in step S01 of FIG. 23, 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 (groove forming step). 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 made smaller than the diameter of the magnetic wire 3.

[0099] Next, as shown in step S03 of FIG. 23, a first wiring portion 41 is formed on the inner wall surface of the groove portion 23 (first wiring step). The formation of the first wiring portion 41 is performed by pattern formation using photolithography.

[0100] Next, as shown in step S04 of FIG. 23, a first insulator 51 is formed (first insulation step).

[0101] Next, as shown in step S05 of FIG. 24, two magnetic wires 3 are placed on the first insulator 51 (wire arrangement step). 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.

[0102] Next, as shown in step S06 of FIG. 24, a second insulator 52 is formed so as to cover the magnetic wire 3 from above and fill the groove portion 23 (second insulation step). The second insulator 52 smoothly connects with the first insulator 51 to form an insulator 5 that covers the entire circumference of the magnetic wire 3. The formation of the second insulator 52 is performed using a nanoimprint method (see FIG. 25) described later.

[0103] Next, as shown in step S07 of FIG. 24, a second wiring portion 42 is formed on the second insulator 52 (second wiring step).

[0104] In forming the second insulator 52 in the above step S06 (second insulation step), a nanoimprint method is used. A specific example of a method for forming the second insulator 52 by the nanoimprint method is shown in FIG. 25.

[0105] When the above wire arrangement step (step S05 in FIG. 24) is completed, two magnetic wires 3 are arranged in the groove portion 23. From this state, as shown in step S061 of FIG. 25, an insulating resin 520 that becomes the second insulator 52 is applied so as to cover the two magnetic wires 3 and fill the groove portion 23.

[0106] Thereafter, as shown in step S062, the mold 6B is pressed against the insulating resin 520 and the insulating resin 520 is exposed. Thereby, the second insulator 52 shown in step S06 of FIG. 24 is formed. The mold 6B in the present embodiment has a concave-shaped surface 62 having a shape along the outer shape of the second insulator 52 to be obtained. The width of the concave-shaped surface 62 in the Y direction is twice or more the diameter of the magnetic wire 3. The rest has the same configuration and effects as those of the first embodiment.

[0107] The present invention is not limited to the above embodiments, and can be applied to various embodiments without departing from the gist thereof.

[0108] The features of the present disclosure are shown as follows. [1] A method for manufacturing a magnetic sensor element including a substrate, a magnetic wire disposed on the substrate, a detection coil including a thin film conductor provided spirally on the outer periphery of the magnetic wire, and an insulator interposed between the magnetic wire and the detection coil, A first wiring step of forming a plurality of first wiring portions that are part of the detection coil in parallel with each other on the substrate; A first insulation step of forming a first insulator that is part of the insulator on the substrate on which the plurality of first wiring portions are formed; A wire arrangement step of arranging the magnetic wire on the surface of the first insulator; A second insulation step of forming a second insulator that is another part of the insulator so as to cover a portion of the magnetic wire that is not in contact with the first insulator; A second wiring step of forming a plurality of second wiring portions that constitute another part of the detection coil on an outer peripheral surface of the second insulator; having A method for manufacturing a magnetic sensor element, wherein at least one of the first insulation step and the second insulation step uses a nanoimprint method. [2] The method for manufacturing a magnetic sensor element according to [1], wherein in the second insulation step, the second insulator is formed using a nanoimprint method. [3] A groove forming step of forming a groove portion having a concave curved inner wall surface on the substrate before the first wiring step, In the first wiring step, a plurality of the first wiring portions are formed on the inner wall surface of the groove portion, In the first insulation step, a plurality of the first insulators are formed on the inner wall surface of the groove portion, In the wire arrangement step, the magnetic wire is arranged in the groove portion. The method for manufacturing a magnetic sensor element according to [1] or [2]. [4] The method for manufacturing a magnetic sensor element according to [3], wherein the first wiring portion and the second wiring portion are formed so as to be smoothly connected. [5] The method for manufacturing a magnetic sensor element according to [3] or [4], wherein the insulator interposed between the magnetic wire and the detection coil is formed to have a film thickness equal to or less than the film thickness of the detection coil over the entire circumference. [6] The method for manufacturing a magnetic sensor element according to any one of [3] to [5], wherein 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. [7] The method for manufacturing a magnetic sensor element according to any one of [3] to [6], wherein in the groove forming step, the groove portion is formed using a nanoimprint method. [8] The method for manufacturing a magnetic sensor element according to any one of [1] to [7], wherein in the first insulation step, the first insulator is formed using a nanoimprint method.

Description of Symbols

[0109] 1 Magnetic sensor element 2 Substrate 3 Magnetic wire 4 Detection coil 41 First wiring portion 42 Second wiring portion 5 Insulator 51 First insulator 52 Second insulator

Claims

1. A method for manufacturing a magnetic sensor element comprising a substrate, a magnetic wire disposed on the substrate, a detection coil composed of a thin film conductor spirally provided on the outer periphery of the magnetic wire, and an insulator interposed between the magnetic wire and the detection coil, a first wiring step of forming a plurality of first wiring portions that are part of the detection coil in parallel on the substrate, a first insulation step of forming a first insulator that is part of the insulator on the substrate on which the plurality of first wiring portions are formed, a wire placement step of placing the magnetic wire on the surface of the first insulator, a second insulation step of forming a second insulator that is another part of the insulator so as to cover a portion of the magnetic wire that is not in contact with the first insulator, a second wiring step of forming a plurality of second wiring portions that constitute another part of the detection coil on the outer peripheral surface of the second insulator, having, In at least one of the first insulation step and the second insulation step, a method for manufacturing a magnetic sensor element using a nanoimprint method.

2. In the second insulation step, the method for manufacturing a magnetic sensor element according to claim 1, wherein the second insulator is formed using a nanoimprint method.

3. Before the first wiring step, there is a groove forming step of forming a groove portion having an inner wall surface with a concave curved surface on the substrate, In the first wiring step, a plurality of the first wiring portions are formed on the inner wall surface of the groove portion, In the first insulation step, a plurality of the first insulators are formed on the inner wall surface of the groove portion, In the wire placement step, the magnetic wire is placed in the groove portion, the method for manufacturing a magnetic sensor element according to claim 1 or 2.

4. The method for manufacturing a magnetic sensor element according to claim 3, wherein the first wiring portion and the second wiring portion are formed so as to be smoothly connected.

5. The method for manufacturing a magnetic sensor element according to claim 4, wherein the insulator interposed between the magnetic wire and the detection coil is formed to have a film thickness equal to or less than the film thickness of the detection coil over the entire circumference.

6. The method for manufacturing a magnetic sensor element according to claim 4, wherein 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.

7. The method for manufacturing a magnetic sensor element according to claim 3, wherein in the groove forming step, the groove portion is formed using a nanoimprint method.

8. The method for manufacturing a magnetic sensor element according to claim 7, wherein in the first insulation step, the first insulator is formed using a nanoimprint method.

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