Method of manufacturing an inductor

Abstract

The present application produces an inductor with less fusion solidification. The production method of the inductor (1) sequentially includes a first step and a second step. In the first step, a magnetic layer laminate (20) including a wiring (2) and a magnetic layer (3) that buries the wiring (2) and contains magnetic particles is produced. The magnetic layer (3) has a first main surface (6) disposed on one side in the thickness direction with respect to the wiring (2) in a manner spaced apart from the wiring (2), and a second main surface (7) spaced apart from the first main surface (6) and disposed on the opposite side of the first main surface (6) with respect to the wiring (2). In the second step, a via hole (10) recessed from the first main surface (6) toward the second main surface (7) is formed in the magnetic layer (3) by a sandblasting method.

Description

Technical Field

[0001] This invention relates to a method for manufacturing an inductor. Background Technology

[0002] Conventionally, an inductor having wiring and a magnetic layer covering the wiring is known (see, for example, Patent Document 1 below). The magnetic layer of Patent Document 1 contains magnetic particles. The inductor of Patent Document 1 also has a slit. The slit is formed in the magnetic layer between two wirings. The slit is formed by laser.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-186365 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] However, to enable electrical connection between the wiring and external devices, sometimes vias are formed in the inductor, and a plating layer is formed inside the vias. The vias extend from the surface of the inductor toward the wiring ground.

[0008] However, if the method in Patent Document 1 is used to form the via, a large amount of molten solidified magnetic particles will remain on the inner circumferential surface of the via due to laser irradiation of the magnetic layer. This results in a problem where the plating layer cannot be stably formed inside the via due to the large amount of molten solidified material.

[0009] This invention manufactures an inductor with less molten solidified material.

[0010] Solution for solving the problem

[0011] The present invention (1) provides a method for manufacturing an inductor, wherein the method comprises: a first step, wherein a magnetic laminate having wiring and a magnetic layer is formed, the magnetic layer burying the wiring and containing magnetic particles, the magnetic layer having a first main surface and a second main surface, the first main surface being disposed on one side of the wiring in the thickness direction at a distance from the wiring, and the second main surface being spaced apart from the first main surface and disposed on the opposite side of the first main surface relative to the wiring; and a second step, wherein after the first step, a recess is formed in the magnetic layer by sandblasting, the recess extending from the first main surface toward the second main surface.

[0012] In this method, since the recesses are formed by sandblasting, there is less molten solidified magnetic particles within the recesses. Therefore, it is possible to manufacture inductors with recesses that have excellent processability.

[0013] The present invention (2) is a method for manufacturing an inductor according to (1), wherein the second step comprises: a third step in which a barrier layer having an opening corresponding to the recess is disposed on the first main surface; and a fourth step in which abrasive particles are sprayed toward the portion of the first main surface exposed from the opening.

[0014] In this method, abrasive particles are sprayed toward the portion exposed from the opening on the first main surface, thus reliably forming a recess of the desired shape.

[0015] The present invention (3) is a method for manufacturing an inductor according to (1) or (2), wherein, in the first step, a magnetic laminate having the wiring is fabricated, the wiring having a conductor and an insulating film disposed on the periphery of the conductor, and in the second step, a via corresponding to the recess is formed in the magnetic layer such that one side of the insulating film in the thickness direction is exposed, the via having an inner peripheral surface extending from the first main surface to the insulating film.

[0016] In this method, since a through-hole corresponding to the recess is formed, if a conductive member is provided in the through-hole, electrical connection between the wiring and external devices can be achieved. On the other hand, since an insulating film covers the wire before the conductive member is provided, the deterioration and damage of the wire can be suppressed.

[0017] The present invention (4) is a method for manufacturing an inductor according to (3), wherein one end edge of the inner peripheral surface in the thickness direction has a longest length D1 and a shortest length D2 in a surface direction orthogonal to the thickness direction, and the ratio of the longest length D1 to the shortest length D2, i.e., D1 / D2, is 10 or less.

[0018] In this method, since the ratio (D1 / D2) is as small as 10 or less, it is possible to stably form conductive components.

[0019] The present invention (5) is a method for manufacturing an inductor according to (3) or (4), wherein the method for manufacturing an inductor further comprises a step of filling a processing stabilizing layer into the via.

[0020] In this method, the machining stability of the via is improved by filling the via with a machining stabilizing layer.

[0021] The present invention (6) is a method for manufacturing an inductor according to (5), wherein the method for manufacturing an inductor further comprises a step of forming a through hole in the thickness direction through the processing stabilizing layer and the insulating film by exposing one side of the conductor in the thickness direction.

[0022] In this method, since the through hole exposes one side of the wire in the thickness direction, the wire can be electrically connected to an external device through the through hole.

[0023] Furthermore, even when conductive components are installed by filling through-holes, the insulation between the conductive components and the magnetic layer can be ensured by using a processing stabilizing layer.

[0024] The present invention (7) is a method for manufacturing an inductor according to (6), wherein the through hole is formed by laser processing.

[0025] In this method, through holes can be formed with good precision because they are formed by laser processing.

[0026] The present invention (8) is a method for manufacturing an inductor according to (1) or (2), wherein, in the first step, a magnetic laminate having a plurality of said wirings is fabricated, the plurality of said wirings being arranged at intervals in a direction orthogonal to both the direction in which the wirings extend and the thickness direction, and in the second step, a slit corresponding to the recess is formed between the plurality of said wirings.

[0027] In this method, crosstalk between multiple wirings can be suppressed because the slits are formed between multiple wirings.

[0028] The effects of the invention

[0029] The manufacturing method of the present invention can produce inductors with less molten solidified material. Attached Figure Description

[0030] Figures 1A to 1E This is a cross-sectional view illustrating the first embodiment of the method for manufacturing the inductor according to the present invention. Figure 1A This is the process of preparing magnetic laminates. Figure 1B It is the process of forming a barrier layer (Japanese: レジスト). Figure 1C This is the process of forming a through hole. Figure 1D It is the process of removing the barrier layer. Figure 1E It refers to the form in which conductive components are formed in the through-hole.

[0031] Figure 2A and Figure 2B They are respectively with Figure 1A and Figure 1D The corresponding top view. Figure 2A It is a magnetic laminate. Figure 2B It is an inductor.

[0032] Figure 3 yes Figure 1D An enlarged view of the inductor shown.

[0033] Figure 4 Is with Figure 3 Image processing diagram of the SEM image of the inductor corresponding to Embodiment 1.

[0034] Figure 5 yes Figure 1D An enlarged cross-sectional view of the inductor shown along the first direction.

[0035] Figure 6 This is a processed image of the SEM photograph of the inductor in Comparative Example 1.

[0036] Figure 7 yes Figure 2B The example shown is a variation of the inductor.

[0037] Figure 8 yes Figure 2B The example shown is a variation of the inductor.

[0038] Figure 9 yes Figure 1D The example shown is a variation of the inductor.

[0039] Figure 10A and Figure 10B respectively with Figure 1D and Figure 1E Correspondingly. Figure 10A This is a variation of an inductor. Figure 10B This is a diagram showing an inductor that further incorporates conductive components.

[0040] Figure 11 yes Figure 1D The example shown is a variation of the inductor.

[0041] Figure 12 yes Figure 1D The example shown is a variation of the inductor.

[0042] Figure 13 This is a cross-sectional view of an inductor obtained through the second embodiment of the inductor manufacturing method of the present invention.

[0043] Figure 14 This is a cross-sectional view of an inductor obtained through the third embodiment of the inductor manufacturing method of the present invention.

[0044] Figures 15A-15B This is an inductor obtained through the fourth embodiment of the inductor manufacturing method of the present invention. Figure 15A It is a top view. Figure 15BIt is a sectional view.

[0045] Figures 16A to 16F This is a cross-sectional view of the fifth embodiment. Figure 16A This is the process of preparing magnetic laminates. Figure 16B It is the process of forming the processing stabilized layer and the second processing stabilized layer. Figure 16C It is the process of forming the through holes and slits. Figure 16D It is a process of reforming the processing stabilized layer. Figure 16E This is the process of forming through holes. Figure 16F It refers to the form in which conductive components are formed through holes.

[0046] Explanation of reference numerals in the attached figures

[0047] 1. Inductor; 2. Wiring; 3. Magnetic layer; 4. Conductor; 5. Insulating film; 6. First main surface; 7. Second main surface; 9. Inner peripheral surface; 10. Through hole (an example of a recess); 11. One side; 20. Magnetic laminate; 21. Barrier layer; 22. Opening; 24. Processing stabilizing layer; 30. Through hole; 34. One side; 40. Slit (an example of a recess). Detailed Implementation

[0048] Reference Figures 1A to 5 The first embodiment of the method for manufacturing the inductor of the present invention will be described.

[0049] The manufacturing method of inductor 1 includes a first step and a second step. In this manufacturing method, the first step and the second step are performed sequentially.

[0050] like Figure 1A and Figure 2A As shown, in the first step, a magnetic laminate 20 is fabricated. The magnetic laminate 20 has not yet formed the through-hole 10 (described later, see reference). Figure 1C and Figure 2B Inductor 1.

[0051] The magnetic laminate 20 has a predetermined thickness and a generally flat shape. The magnetic laminate 20 is longer in a first direction orthogonal to the thickness direction. The magnetic laminate 20 has a rectangular shape when viewed from above. Figure 1A As shown, the magnetic laminate 20 has one side 11 and another side 12. The one side 11 and the other side 12 are spaced apart and arranged opposite to each other on one side in the thickness direction. The magnetic laminate 20 has wiring 2 and a magnetic layer 3.

[0052] like Figure 2A As shown, wiring 2 extends along the first direction. The shape, size, structure, material, and formulation (filler ratio, content ratio, etc.) of wiring 2 are described, for example, in Japanese Patent Application Publication No. 2019-220618. Preferably, as... Figure 1A As shown, the wiring 2 has a generally circular shape in cross-sections along the thickness direction and the second direction. The second direction is orthogonal to both the thickness direction and the first direction. The wiring 2 includes an outer peripheral surface 14 in the aforementioned cross-sections. Preferably, the wiring 2 includes a conductor 4 made of a conductor and an insulating film 5 covering the peripheral surface of the conductor 4.

[0053] The magnetic layer 3 has the same external shape as the magnetic laminate 20 when viewed from above. The magnetic layer 3 has a sheet shape extending along the first direction. Furthermore, the magnetic layer 3 embeds the wiring 2 when viewed in cross-section. The material of the magnetic layer 3 is a magnetic composition comprising an adhesive and magnetic particles. From the viewpoint of improving the inductance of the inductor 1, the magnetic particles are preferably soft magnetic particles. The magnetic composition and the method for forming the magnetic layer 3 have been described in detail, for example, in Japanese Patent Application Publication Nos. 2019-165221 and 2019-165222. The magnetic layer 3 has a first main surface 6, which is an example of a first main surface, a second main surface 7, which is an example of a second main surface, and an outer surface 8.

[0054] like Figure 1A As shown, the first main surface 6 forms one side of the magnetic layer 3 in the thickness direction. The first main surface 6 is also one side 11 of the magnetic laminate 20. The first main surface 6 is disposed on one side of the thickness direction relative to the wiring 2 in a spaced-apart manner from the wiring 2. The first main surface 6 includes a curved surface corresponding to the wiring 2.

[0055] The second main surface 7 forms the other side of the magnetic layer 3 in the thickness direction. The second main surface 7 is also the other side 12 of the magnetic laminate 20. The second main surface 7 is located on the other side of the first main surface 6 in the thickness direction, spaced apart from the first main surface 6. The second main surface 7 is disposed on the opposite side of the first main surface 6 relative to the wiring 2. The second main surface 7 includes a curved surface corresponding to the wiring 2.

[0056] like Figure 1A and Figure 2A As shown, the outer surface 8 consists of two opposing sides of the magnetic layer 3, spaced apart in the second direction. The outer surface 8 connects the two end edges of the first main surface 6 and the two end edges of the second main surface 7 in the second direction, respectively.

[0057] The method for manufacturing the magnetic laminate 20 is described in detail, for example, in Japanese Patent Application Publication Nos. 2019-165221 and 2019-165222.

[0058] like Figures 1B to 1DAs shown, in the second step, a via 10, which is an example of a recess, is formed in the magnetic layer 3. The second step is performed after the first step. In forming the via 10, a sandblasting method is used. The sandblasting method includes a third step, a fourth step, and a fifth step.

[0059] like Figure 1B As shown, in the third step, a barrier layer 21 is disposed on the first main surface 6. The barrier layer 21 has an opening 22 corresponding to the via 10. The opening 22 extends through the barrier layer 21 in the thickness direction. The barrier layer 21 is made of a material that is not easily damaged by collision with the abrasive particles described below. The material of the barrier layer 21 is not particularly limited. Commercially available products can be used for the barrier layer 21, for example, commercially available "dry film resist for sandblasting" can also be used. The barrier layer 21 is formed by a photolithography process.

[0060] like Figure 1C As shown, in the fourth step, abrasive particles are sprayed toward the portion of the first main surface 6 exposed from the opening 22. An abrasive particle spraying device (not shown) is used for spraying the abrasive particles.

[0061] An abrasive particle ejection device, for example, comprises, in sequence with respect to the flow direction of the abrasive particles, an inlet section, an extension section, a rectifying section, a collecting section, and an ejection nozzle (not shown). The inlet section is connected to both an abrasive particle container and an air container. The extension section diffuses the abrasive particles internally. The rectifying section regulates the flow of the abrasive particles. The collecting section collects the abrasive particles while increasing the flow pressure. The ejection nozzle has multiple nozzles. Each nozzle is a generally circular orifice. The ejection nozzle ejects abrasive particles from the multiple nozzles in a uniform manner. The structure and operating conditions of the abrasive particle ejection device are described, for example, in Japanese Patent Application Publication No. 2015-199131. Commercially available abrasive particle ejection devices can be used.

[0062] Specifically, examples of abrasive particles include alumina, glass microspheres, silicon carbide, silicon nitride, zirconium oxide, and stainless steel. The nozzle diameter is, for example, 0.1 μm or more, preferably 0.5 μm or more, and also, for example, 10000 μm or less, preferably 5000 μm or less. The median particle size of the abrasive particles is, for example, 0.1 μm or more, preferably 0.5 μm or more, and also, for example, 1000 μm or less, preferably 100 μm or less. The injection pressure of the abrasive particles is, for example, 0.01 MPa or more, preferably 0.05 MPa or more, and also, for example, 10 MPa or less, preferably 5 MPa or less.

[0063] In the fourth step, the portion of the first main surface 6 exposed from the opening 22 is ground, and then a through hole 10 is formed in the magnetic layer 3.

[0064] like Figure 1DAs shown, in the fifth step, the barrier layer 21 is removed. Specifically, the barrier layer 21 is peeled off from the first main surface 6.

[0065] Thus, an inductor 1 with wiring 2, magnetic layer 3 and through hole 10 can be obtained.

[0066] like Figure 2B As shown, the vias 10 are disposed on the magnetic layer 3 such that they correspond to the two ends of the wiring 2 in the first direction. The two vias 10 each have a generally circular shape when viewed from above.

[0067] like Figures 3-5 As shown, the via 10 extends from one side 11 of the inductor 1 through the magnetic layer 3 toward the wiring 2. The via 10 exposes one side 34 of the insulating film 5 in the thickness direction. The side 34 in the thickness direction is the portion of the outer peripheral surface 14 of the wiring 2 located on the side closer to the center in the thickness direction. The via 10 has an inner peripheral surface 9 and a bottom surface 17.

[0068] The inner circumferential surface 9 faces the interior of the via 10 within the magnetic layer 3. For example... Figure 2B As shown, the inner circumferential surface 9 is annular in shape when viewed from above (the same meaning applies when viewed from the thickness direction, hereinafter the same). Specifically, the inner circumferential surface 9 has a roughly annular shape when viewed from above. Figures 3-5 As shown, the inner peripheral surface 9 has a slope 27 that increases in cross-sectional area of ​​the opening of the through hole 10 as it approaches one side surface 11. Specifically, the inner peripheral surface 9 is formed by the slope 27. The inner peripheral surface 9 has steps 13. For each through hole 10, the number of steps 13 is, for example, one.

[0069] The bottom surface 17 faces the through hole 10. The bottom surface 17 is part of the outer peripheral surface 14 of the wiring 2. Additionally, the bottom surface 17 is also one side 34 of the wiring 2 in the thickness direction. The bottom surface 17 is continuous with the end edge (the second end edge E2 described later) on the other side of the inner peripheral surface 9 in the thickness direction. Figure 2B As shown, the bottom surface 17 has a roughly circular shape when viewed from above. Additionally, as... Figure 3 and Figure 4 As shown, the bottom surface 17 has a generally circular arc shape in the cross-section along the second direction. Additionally, as... Figure 5As shown, the bottom surface 17 is flat in cross-section along the first direction. The maximum profile height Rz of the bottom surface 17 is, for example, 10 μm or less, preferably 1 μm or less, more preferably 0.1 μm or less, and also, for example, 0.000001 μm or more. The portion of the side surface 34 in the thickness direction covered by the magnetic layer 3 is the cover portion 18. The maximum profile height Rz of the cover portion 18 is, for example, 10 μm or less, preferably 1 μm or less, more preferably 0.1 μm or less, and also, for example, 0.000001 μm or more. The ratio of the maximum profile height Rz of the bottom surface 17 to the maximum profile height Rz of the cover portion 18 is, for example, less than 2, preferably 1.5 or less, more preferably 1.1 or less, and also, for example, more than 1. If this ratio is lower than the above upper limit, it is possible to suppress excessive roughness of the bottom surface 17 of the via 10 relative to the cover portion 18. Therefore, it is possible to reliably form the conductive member 19 in the via 10.

[0070] The magnetic layer 3 can be a single layer or multiple layers. In the case of multiple layers, for example, it includes a first layer 15 for burying the wiring 2 and two second layers 16. The two second layers 16 are respectively disposed on one side and the other side of the first layer 15 in the thickness direction. The type and / or proportion of magnetic particles in the second layer 16 are different from the type and / or proportion of magnetic particles in the first layer 15.

[0071] Furthermore, in this inductor 1, the upper limit of the percentage of molten solidified material M is, for example, 10% or less, preferably 7.5%, more preferably 5%, further preferably 2.5%, particularly preferably 1%, even more preferably 0.1%, and still more preferably 0.01%, and the most preferably 0% of the percentage of molten solidified material M.

[0072] The percentage of the molten solidified material M can be determined using the following method.

[0073] First, such as Figures 3-5 As shown, in the cross section of the through hole 10, points P1 and P2, and points P3 and P4 are determined. Points P1 and P2 are located 50 μm apart from the first end edge E1 on one side and the other side of the direction extending from the first main surface 6, respectively, with reference to the first end edge E1 on one side of the thickness direction of the inner circumferential surface 9. Points P3 and P4 are located 50 μm apart from the second end edge E2 on one side and the other side of the direction extending from the second end edge E2 on the other side of the thickness direction of the inner circumferential surface 9, respectively.

[0074] The cross section of the through hole 10 can be as follows Figure 3 and Figure 4 The cross-section shown is along the second direction, or it can be as follows: Figure 5 The cross-section shown is along the first direction.

[0075] The first end edge E1 is the angle formed by the inner circumferential surface 9 and the first main surface 6. In the cross-section along the second direction, as... Figure 3 and Figure 4 As shown, if the first main surface 6 is a curved surface, then the direction in which the first main surface 6 extends is the tangential direction at the first end edge E1. On the other hand, in a cross-section along the first direction, as... Figure 5 As shown, if the first main surface 6 is a flat surface, then the direction in which the first main surface 6 extends is along the direction of the first main surface 6, which is the first direction.

[0076] The second edge E2 is the angle formed by the inner peripheral surface 9 and the outer peripheral surface 14 of the wiring 2. The direction that serves as the reference when determining the third point P3 and the fourth point P4 using the second edge E2 as a reference is the same as the direction that serves as the reference when determining the first point P1 and the second point P2. Therefore, the first line segment L1 connecting the first point P1 and the second point P2 is parallel to the second line segment L2 connecting the third point P3 and the fourth point P4. This forms a quadrilateral with vertices at the first point P1, the second point P2, the third point P3, and the fourth point P4. This quadrilateral is a parallelogram, meaning it has two parallel sides (the first line segment L1 and the second line segment L2).

[0077] Next, obtain the area S0 of the quadrilateral.

[0078] Next, the area S1 of the molten solidified material M located inside the quadrilateral is obtained. The molten solidified material M is formed during the fabrication of the via 10 using the manufacturing method described later. Figure 6 A molten solidified material is formed by the melting, aggregation, and solidification of magnetic particles as shown. For example, the molten solidified material M can also be defined as follows: By observing a cross-sectional SEM image, the perimeter of 10 unmelted magnetic particles is calculated, and the average value is determined. Additionally, by observing a cross-sectional SEM image, the area of ​​10 unmelted magnetic particles is calculated, and the average value is determined. An object having a perimeter larger than the average perimeter of the aforementioned magnetic particles and an area larger than the average area of ​​the aforementioned magnetic particles is a molten solidified material.

[0079] Next, the percentage of the area S1 of the molten solidified material relative to the area S0 of the quadrilateral is calculated (S1 / S0×100%).

[0080] If the percentage of the molten solidified material M is below the above upper limit, then it can be as follows: Figure 1E The conductive member 19, described later, is stably formed inside the via 10 as shown.

[0081] Next, the use of inductor 1 will be explained.

[0082] like Figure 1EAs shown, the conductive member 19 is formed in the via 10, for example, by plating, specifically by electroless plating and / or electroplating. Preferably, the conductive member 19 is formed by electroless plating and electroplating. In this case, a decontamination (cleaning and roughening) process is performed, followed by electroless plating, then preparation, exposure and development of a photosensitive dry film resist to form a plating barrier layer, followed by electroplating using the plating barrier layer, and finally removal of the plating barrier layer.

[0083] Furthermore, before forming the conductive member 19, the portion of the insulating film 5 located at the via 10 is peeled off. The insulating film 5 can be peeled off by various methods, such as laser processing or sandblasting. Also, a seed layer (not shown) is formed before electroplating. The conductive member 19 is formed by precipitation from the bottom surface 17 of the via 10. Additionally, the conductive member 19 precipitates along the inner peripheral surface 9 towards one side in the thickness direction. Furthermore, the conductive member 19 is also formed on one side 11 surrounding the via 10. For example, copper or other conductors can be used as materials for the conductive member 19.

[0084] [Effects of the First Embodiment]

[0085] Furthermore, in this method, since the via 10 is formed by sandblasting, the amount of molten solidified magnetic particles M in the via 10 is relatively small. Specifically, the percentage of molten solidified material M is, for example, 10% or less. Therefore, it is possible to manufacture an inductor 1 with via 10 having excellent processability.

[0086] In contrast, if the via 10 is formed by laser, then as Figure 6 As shown, there is a large amount of molten solidified material M of magnetic particles. Specifically, the percentage of molten solidified material M exceeds 10%, for example. Therefore, it is impossible to manufacture an inductor 1 with a via 10 that has excellent machinability.

[0087] Furthermore, in the second step of this method, since abrasive particles are sprayed toward the portion exposed from the opening 22 of the barrier layer 21 toward the first main surface 6, the via hole 10 of the desired shape can be formed with good precision.

[0088] Furthermore, in this method, such as Figure 1E As shown, if a conductive member 19 is provided in the through-hole 10, the wiring 2 can be electrically connected to the external device. On the other hand, as... Figure 1D As shown, in the inductor 1 before the conductive member 19 is provided in the through hole 10, the insulating film 5 covers the wire 4, thus suppressing the deterioration and damage of the wire 4.

[0089] [Modifications of the First Embodiment]

[0090] In the modified examples, the same reference numerals are used for components and processes identical to those in the first embodiment, and detailed descriptions are omitted. Furthermore, in the modified examples, unless otherwise specified, the same effects as in the first embodiment can be achieved. Moreover, the first embodiment and the modified examples can be appropriately combined.

[0091] In the first embodiment, when viewed from above, the inner peripheral surface 9 has a ring shape, but as Figure 7 As shown, the inner circumferential surface 9 has an end shape. Furthermore, in this modified example, the slit 40, as an example of a recess, has two inner circumferential surfaces 9.

[0092] In top view, slit 40 extends along wiring 2. In top view, slit 40 overlaps with wiring 2. Specifically, in top view, slit 40 is contained within wiring 2. Slit 40 has two inner peripheral surfaces 9. The two inner peripheral surfaces 9 are opposite each other in a second direction. In top view, each of the two inner peripheral surfaces 9 has a straight shape along a first direction. In top view, each of the two inner peripheral surfaces 9 has an end shape, specifically having two ends 29 in the first direction.

[0093] However, an attempt was made to use a cutting saw (not shown) to form a slit 40 having an inner circumferential surface 9 with an end shape. The cutting saw, for example, includes a blade and a moving device. The blade is disc-shaped. The blade is rotatable. The moving device allows the blade to move along the thickness direction and a first direction. When forming the slit 40 using the cutting saw, the blade is brought into contact with one side of the first main surface 6 in the thickness direction, and then moved to the other side in the thickness direction until the circumferential surface of the blade contacts the insulating film 5. Next, the blade is moved along the first direction. Thus, a slit 40 having two inner circumferential surfaces 9 is formed.

[0094] However, in this attempt, the magnetic particles in the magnetic layer 3 deform due to the rotating blade. For example, when the magnetic particles come into contact with the blade rotating along the thickness direction and are drawn in, the magnetic particles are pulled apart (or stretched) in the thickness direction, and then re-bonded, eventually forming a molten solidified material M.

[0095] On the other hand, in this method, instead of using a cutting saw, a sandblasting method using abrasive particles is employed, thus suppressing the formation of the aforementioned molten solidified product M.

[0096] The shape of the through hole 10 is not limited to a roughly circular shape when viewed from above. For example... Figure 8 As shown, for example, the via 10 has a generally rectangular shape when viewed from above. In this variation, the via 10 is longer in the first direction when viewed from above. The via 10 has a longest length D1 and a shortest length D2 when viewed from above.

[0097] In this variation, the longest length D1 is the distance between two opposite vertices in the rectangular shape of the via 10. The shortest length D2 is the length of the via 10 in the second direction. The upper limit of the ratio (D1 / D2) of the longest length D1 to the shortest length D2 is, for example, 10, preferably 5, more preferably 3, and even more preferably 2. The lower limit of this ratio is, for example, 1.1, preferably 1.2. Furthermore, in Figure 2B In the circular shape of the via 10 shown, the longest length D1 and the shortest length D2 are the same. If the ratio (D1 / D2) is less than 10, a conductive member 19 can be stably formed in the via 10.

[0098] like Figure 9 As shown, the inner circumferential surface 9 can also be a flat surface when viewed in section.

[0099] In another variation, such as Figure 10A As shown, the inner circumferential surface 9 has a slope 27 and a second slope 28.

[0100] For slope 27, as it approaches one side 11, the opening cross-sectional area of ​​the through hole 10 increases.

[0101] Slope 27 extends from the second end edge E2 toward the thickness direction.

[0102] On the other hand, for the second slope 28, the opening cross-sectional area of ​​the through hole 10 decreases as it approaches one side 11. The second slope 28 extends from the first end edge E1 to one end edge of the slope 27 in the thickness direction. On the inner circumferential surface 9, the slope 27 and the second slope 28 are arranged sequentially on the thickness side.

[0103] The distance in the second direction between one end edge of the two second slope surfaces 28 in the thickness direction is the distance in the second direction between the two first end edges E1. The distance in the second direction between the two first end edges E1 is shorter than the distance in the second direction between the other end edges E3 of the two second slope surfaces 28 in the thickness direction. The ratio of the distance in the second direction between the two other end edges E3 to the distance in the second direction between the two first end edges E1 is, for example, 1.1 or more, preferably 1.2 or more, more preferably 1.5 or more, and for example, 3 or less.

[0104] The distance in the second direction between the other ends of the two slope surfaces 27 in the thickness direction is the distance between the two E2. The distance in the second direction between the two second ends E2 is shorter than the distance in the second direction between the two other ends E3 in the thickness direction. The ratio of the distance in the second direction between the two other ends E3 to the distance in the second direction between the two second ends E2 is, for example, 1.1 or more, preferably 1.2 or more, more preferably 1.5 or more, and for example, 3 or less.

[0105] When fabricating the via 10, for example, make Figure 1B The opening 22 of the barrier layer 21 shown is narrow. Specifically, the diameter of the opening 22 is, for example, 300 μm or less, preferably 200 μm or less.

[0106] Therefore, in the fourth step, the abrasive particles collide with the first main surface 6 of the magnetic layer 3 through the narrow opening 22 to grind the magnetic layer 3. However, the abrasive particles tend to remain on the magnetic layer 3 on the other side of the thickness direction around the opening 22. The abrasive particles flow upstream in the jet direction. At this time, the abrasive particles form an inner circumferential surface 9 with a roughly arc-shaped trajectory. Thus, the abrasive particles form an inner circumferential surface 9 with a second slope 28 and a slope 27.

[0107] like Figure 10B As shown, if the conductive member 19 is provided in the through hole 10, the conductive member 19 will contact the slope 27 and the second slope 28 respectively.

[0108] Furthermore, in this inductor 1, the conductive member 19 can be prevented from falling off the through hole 10 based on the anchoring effect.

[0109] like Figure 11 As shown, it is also possible that the inner circumferential surface 9 does not have a slope 27, but only a second slope 28.

[0110] The shape of wiring 2 is not limited. For example... Figure 12 As shown, the shape of the wiring 2 can be approximately rectangular in cross-section. The other side of the wiring 2 in the thickness direction contacts the insulating layer 23. The insulating layer 23 extends along the second direction. For example, insulating resins such as polyimide can be used as materials for the insulating layer 23.

[0111] Furthermore, the inductor 1 in this modified example has multiple (specifically two) wirings 2. The multiple wirings 2 are adjacent to each other at intervals. The multiple wirings 2 are parallel.

[0112] Alternatively, the second sandblasting process can be performed without using the barrier layer 21, but this is not shown. Preferably, the barrier layer 21 is used. Specifically, abrasive particles are sprayed onto the portion of the first main surface 6 exposed from the opening 22 of the barrier layer 21. This reliably forms a through-hole 10 corresponding to the shape of the opening 22.

[0113] Alternatively, the through hole 10 can be provided on one side 11 and the other side 12, but this is not shown in the figure.

[0114] Alternatively, the via 10 can be provided only at one end of the wiring 2 in the first direction within the magnetic layer 3, but this case is not shown.

[0115] [Second Implementation]

[0116] In the second embodiment, the same reference numerals are used for components and processes identical to those in the first embodiment, and detailed descriptions are omitted. Furthermore, in the second embodiment, unless otherwise specified, the same effects as in the first embodiment can be achieved. Moreover, the first and second embodiments can be appropriately combined.

[0117] like Figure 13 As shown, the second embodiment includes not only the first and second steps of the first embodiment, but also a step of filling the via 10 with the processing stabilizing layer 24. Furthermore, the second embodiment also includes a step of disposing the second processing stabilizing layer 25 on the second main surface 7. This second embodiment includes a step of providing the processing stabilizing layer 24 and the second processing stabilizing layer 25 on the inductor 1. This step is performed after the second step.

[0118] When a processing stabilizing layer 24 and a second processing stabilizing layer 25 are provided in inductor 1, such as Figure 13 As shown by the imaginary line, two processing stabilized sheets 26 are prepared. Each of the two processing stabilized sheets 26 comprises a thermosetting resin composition. The thermosetting resin composition contains a thermosetting resin as an essential component. The thermosetting resin includes a base agent, a curing agent, and a curing accelerator.

[0119] Examples of main agents include epoxy resins and silicone resins, with epoxy resins being the most preferred. Examples of epoxy resins include bifunctional epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, modified bisphenol A type epoxy resin, modified bisphenol F type epoxy resin, modified bisphenol S type epoxy resin, and biphenyl type epoxy resin; and multifunctional epoxy resins with three or more functional groups, such as phenolic varnish epoxy resin, cresol varnish epoxy resin, trihydroxyphenylmethane type epoxy resin, tetraphenolyl ethane type epoxy resin, and dicyclopentadiene type epoxy resin. These epoxy resins can be used alone or in combination of two or more. Bifunctional epoxy resins are preferred, and bisphenol A type epoxy resins are more preferred. The lower limit of the epoxy equivalent of the epoxy resin is, for example, 10 g / eq., and the upper limit is, for example, 1000 g / eq.

[0120] As a curing agent, if the main agent is an epoxy resin, examples include phenolic resins and isocyanate resins. Examples of phenolic resins include polyfunctional phenolic resins such as phenolic varnish resin, cresol phenolic varnish resin, phenol aralkyl resin, phenol biphenyl resin, dicyclopentadiene-type phenolic resin, and methyl phenolic resin. These phenolic resins can be used alone or in combination of two or more. Phenolic varnish resin and phenol biphenyl resin are preferred examples of phenolic resins. If the main agent is an epoxy resin and the curing agent is a phenolic resin, the lower limit of the total number of hydroxyl groups in the phenolic resin relative to one equivalent of epoxy groups in the epoxy resin is, for example, 0.7 equivalents, preferably 0.9 equivalents, and the upper limit is, for example, 1.5 equivalents, preferably 1.2 equivalents. Specifically, the lower limit of the number of parts by mass of the curing agent relative to 100 parts by mass of the main agent is, for example, 1 part by mass, and the other is, for example, 50 parts by mass.

[0121] As a curing accelerator, it is a catalyst (thermosetting catalyst) that promotes the curing of the main agent (preferably an epoxy resin curing accelerator), for example, organophosphorus compounds, such as imidazole compounds like 2-phenyl-4-methyl-5-hydroxymethylimidazolium (2P4MHZ). The lower limit of the mass fraction of the curing accelerator relative to 100 parts by mass of the main agent is, for example, 0.05 parts by mass, and the upper limit is, for example, 5 parts by mass.

[0122] Furthermore, the thermosetting resin composition may, for example, contain particles as an arbitrary component. The particles are dispersed in the thermosetting resin. The particles are, for example, at least one type of particles selected from the group consisting of the first particle and the second particle.

[0123] The first particle has, for example, a generally spherical shape. The lower limit of the median particle size of the first particle is, for example, 1 μm, preferably 5 μm, and the upper limit is, for example, 250 μm, preferably 200 μm. The median particle size of the first particle can be determined using a laser diffraction-based particle size distribution measurement device. Alternatively, the median particle size of the first particle can also be determined, for example, through binarization processing based on cross-sectional observation.

[0124] The material of the first particle is not particularly limited. Examples of materials for the first particle include metals, inorganic compounds, and organic compounds. To improve the coefficient of thermal expansion, metals and inorganic compounds are preferred.

[0125] When the processing stabilizing layer 24 functions as an inductance-enhancing layer, a metal is included in the thermosetting resin composition. Examples of metals include magnetic materials exemplified in the magnetic layer 3, preferably organoferric compounds containing iron as the first metal element, and more preferably iron carbonyl.

[0126] When the processing stabilizing layer 24 functions as a thermal expansion coefficient suppression layer, an inorganic compound is included in the thermosetting resin composition. Examples of inorganic compounds include inorganic fillers, specifically silica, alumina, etc., with silica being the most preferred.

[0127] Specifically, spherical silicon dioxide is preferably selected as the first particle, and spherical carbonyl iron is also preferably selected.

[0128] The second particle, for example, has a generally flat shape. A generally flat shape includes a generally plate-like shape.

[0129] The lower limit of the flatness (flatness) of the second particle is, for example, 8, preferably 15, and the upper limit is, for example, 500, preferably 450.

[0130] The lower limit of the median particle size of the second particle is, for example, 1 μm, preferably 5 μm, and the upper limit of the median particle size of the second particle is, for example, 250 μm, preferably 200 μm.

[0131] The median particle size of the second particle can be determined using the same method as the median particle size of the first particle.

[0132] The lower limit of the average thickness of the second particle is, for example, 0.1 μm, preferably 0.2 μm, and the upper limit is, for example, 3.0 μm, preferably 2.5 μm.

[0133] The material of the second particle is, for example, an inorganic compound. Examples of inorganic compounds include thermally conductive compounds such as boron nitride. Therefore, it is preferable that the inorganic compound is included in the thermosetting resin composition so that the processing stabilizing layer 24 functions as a thermal conductivity improving layer.

[0134] Specifically, as the second particle, boron nitride with a flat shape is preferably taken.

[0135] The thermosetting resin composition contains one of the first particle and the second particle, or contains both the first particle and the second particle.

[0136] The lower limit of the mass fraction of particles (first particle and / or second particle) relative to 100 parts by mass of thermosetting resin is, for example, 10 parts by mass, preferably 50 parts by mass, and the upper limit of the mass fraction of particles (first particle and / or second particle) is, for example, 2000 parts by mass, preferably 1500 parts by mass. Furthermore, the lower limit of the particle content in the cured product is, for example, 10% by mass, and the upper limit is, for example, 90% by mass. When both the first particle and the second particle are included in the thermosetting resin composition, the lower limit of the mass fraction of the second particle relative to 100 parts by mass of the first particle is, for example, 30 parts by mass, and the upper limit of the mass fraction of the second particle is, for example, 300 parts by mass.

[0137] Furthermore, since particles are any component in a thermosetting resin composition, the thermosetting resin composition may also be free of particles.

[0138] On the other hand, the materials of each of the two processing stabilizers 26 may further contain thermoplastic resin. The lower limit of the mass fraction of thermoplastic resin relative to 100 parts by mass of thermosetting resin is, for example, 1 part by mass, and the upper limit of the mass fraction of thermoplastic resin is, for example, 100 parts by mass.

[0139] Next, pressure is applied to the two processing stabilizers 26 and the inductor 1 from both sides in the thickness direction. Then, they are heated to stage the two processing stabilizers 26. Thus, the inductor 1 has a processing stabilizer layer 24 and a second processing stabilizer layer 25.

[0140] A processing stabilizing layer 24 is disposed on the first main surface 6 of the magnetic layer 3, the inner peripheral surface 9 of the via 10, and one side 34 of the insulating film 5 in the thickness direction. That is, a portion of the processing stabilizing layer 24 is at least filled into the via 10. The processing stabilizing layer 24 improves the surface workability of the first main surface 6 of the magnetic layer 3 and the surface workability of the inner peripheral surface 9 and the via 10. Furthermore, the processing stabilizing layer 24 is also used when the conductive member 19 is disposed in the via 30 (see below) Figure 14 (As in the third embodiment) An insulating layer that ensures insulation between the conductive member 19 and the magnetic layer 3. Additionally, the processing stabilizing layer 24 is also a corrosion suppressing layer that inhibits corrosion of magnetic particles in the magnetic layer 3 during the decontamination process. The lower limit of the thickness of the processing stabilizing layer 24 is, for example, 1 μm, preferably 10 μm, and the upper limit is, for example, 1000 μm, preferably 100 μm. The lower limit of the ratio of the thickness of the processing stabilizing layer 24 to the thickness of the inductor 1 is, for example, 0.001, preferably 0.005, more preferably 0.01, and the upper limit is, for example, 0.5, preferably 0.3, more preferably 0.1. Furthermore, the thickness of the processing stabilizing layer 24 is the shortest length between the first main surface 6 and one side of the processing stabilizing layer 24 in the thickness direction.

[0141] The second processing stabilizing layer 25 is disposed on the second main surface 7 of the magnetic layer 3. That is, the second processing stabilizing layer 25 is disposed on the other side 12 of the inductor 1. The second processing stabilizing layer 25 improves the surface workability of the other side 12 of the inductor 1. The lower limit of the thickness of the second processing stabilizing layer 25 is, for example, 1 μm, preferably 10 μm, and the upper limit is, for example, 1000 μm, preferably 100 μm. The lower limit of the ratio of the thickness of the second processing stabilizing layer 25 to the thickness of the inductor 1 is, for example, 0.001, preferably 0.005, more preferably 0.01, and the upper limit is, for example, 0.5, preferably 0.3, more preferably 0.1. Furthermore, the thickness of the second processing stabilizing layer 25 is the shortest length between the second main surface 7 and the other side in the thickness direction of the second processing stabilizing layer 25.

[0142] [Effects of the Second Embodiment]

[0143] In the second embodiment, since a portion of the processing stabilizing layer 24 is filled into the via 10, the processing stability of the via 10 can be improved. Specifically, the stability of subsequent processing of the via 10 (the third embodiment described later) can be improved.

[0144] [Third Implementation]

[0145] In the third embodiment, the same reference numerals are used for components and processes identical to those in the first and second embodiments, and detailed descriptions are omitted. Furthermore, in the third embodiment, unless otherwise specified, the same effects as in the first and second embodiments can be achieved. Moreover, the first to third embodiments can be appropriately combined.

[0146] like Figure 14 As shown, in the third embodiment, in addition to the steps of the second embodiment, there is also a step of forming the through hole 30.

[0147] The through-hole 30 extends through the stabilizing layer 24 and the insulating film 5 in the thickness direction. A side 36 in the thickness direction of the conductor 4 is exposed through the through-hole 30. For example, a side 36 in the thickness direction of the conductor 4 is exposed from a portion of the insulating film 5 and the stabilizing layer 24.

[0148] The processing stabilizing layer 24 obtained in the third embodiment includes a first covering portion 31 and a second covering portion 32. The first covering portion 31 covers the first main surface 6 following the first main surface 6. The first covering portion 31 is located on one side of the first main surface 6 in the thickness direction. The second covering portion 32 covers the inner peripheral surface 9 following the inner peripheral surface 9. The second covering portion 32 overlaps with the inner peripheral surface 9 when projected along the second direction (or the first direction). In addition, the second covering portion 32 extends along the thickness direction. The other end face of the second covering portion 32 in the thickness direction contacts the protruding end portion 35 of the insulating film 5 from one side in the thickness direction. The other end face of the second covering portion 32 in the thickness direction is the side of the second covering portion 32 located opposite to the side where the first covering portion 31 is located. The protruding end portion 35 is part of the insulating film 5. The protruding end portion 35 has a generally annular shape when viewed from above. Furthermore, the annular shape of the protruding end portion 35 is... Figure 14 Not shown in the drawing. The protruding end 35 exposes a portion of the side 36 of the conductor 4 in the thickness direction on its inner side. The inner side of the protruding end 35 is flush with the inner side of the second cover 32.

[0149] Thus, the protruding end 35 of the insulating film 5 and the second covering portion 32 of the processing stabilizing layer 24 expose one side 36 of the conductor 4 in the thickness direction towards the thickness direction.

[0150] The through hole 30 is defined by the second cover portion 32 of the processing stabilizing layer 24, the protruding end 35 of the insulating film 5, and the side 36 of the conductor 4 in the thickness direction.

[0151] When forming the through hole 30, the processing stabilization layer 24 of the second embodiment is subjected to, for example, perforation processing. Examples of perforation processing include laser processing, drilling, and sandblasting, with laser processing and drilling preferred, and laser processing even more preferred. If laser processing is used, the through hole 30 can be formed with good precision in the processing stabilization layer 24.

[0152] On the other hand, in the sandblasting method, it is sometimes impossible to quickly cut the stabilizing layer 24, thus making it impossible to efficiently form the through hole 30.

[0153] [Effects of the Third Embodiment]

[0154] In the third embodiment, since the through hole 30 exposes one side 36 of the conductor 4 in the thickness direction, if the conductive member 19 shown by the imaginary line is arranged in the through hole 30, the conductor 4 can be electrically connected to the external device.

[0155] In this method, if the through hole 30 is formed by laser processing, the through hole 30 can be formed with good precision.

[0156] Furthermore, if the processing stabilizing layer 24 is an insulating layer, then since the processing stabilizing layer 24 is located between the conductive member 19 and the magnetic layer 3, the insulation between them can be improved.

[0157] [Fourth Implementation]

[0158] In the fourth embodiment, the same reference numerals are used for components and processes identical to those in the first to third embodiments, and detailed descriptions are omitted. Furthermore, in the fourth embodiment, unless otherwise specified, the same effects as in the first to third embodiments can be achieved. Moreover, the first to fourth embodiments can be appropriately combined.

[0159] As shown in Figure 15, the slit 40 can also be configured to be staggered from the multiple wirings 2 when viewed from above.

[0160] Viewed from above, the slit 40 penetrates the second layer 16 (second layer 16A on one side) disposed on one side of the first layer 15 in the thickness direction. However, the slit 40 does not penetrate the first layer 15. The slit 40 has an inner peripheral surface 9 and a bottom surface 17. When projected along the second direction, the inner peripheral surface 9 of the slit 40 is offset from the wiring 2 on one side in the thickness direction. In cross-section, the bottom surface 17 of the slit 40 is different from the outer peripheral surface 14 of the wiring 2, but is separated by a gap. Figure 15A and Figure 15B Although not depicted in the diagram, when viewed from above, the slit 40 is parallel to multiple wirings 2.

[0161] [Effects of the Fourth Embodiment]

[0162] By adopting the fourth embodiment, since the slit 40 is formed between the plurality of wirings 2, crosstalk between the plurality of wirings 2 can be suppressed.

[0163] [Modifications of the fourth embodiment]

[0164] In the modified examples, the same reference numerals are used for components and processes identical to those in the fourth embodiment, and detailed descriptions are omitted. Furthermore, in the modified examples, unless otherwise specified, the same effects as in the fourth embodiment can be achieved. Moreover, the fourth embodiment and the modified examples can be appropriately combined.

[0165] When projected along the second direction, slit 40 may also overlap with wiring 2, which is not shown in the figure.

[0166] The slit 40 may also penetrate the magnetic layer 3 in the thickness direction, as not shown. In this variation, the slit 40, when viewed from above, may have, for example, a tear-off line shape.

[0167] [Fifth Implementation]

[0168] In the fifth embodiment, the same reference numerals are used for components and processes identical to those in the first to fourth embodiments, and detailed descriptions are omitted. Furthermore, in the fourth embodiment, unless otherwise specified, it achieves the same effects as the first to fourth embodiments. Moreover, the first to fifth embodiments can be appropriately combined.

[0169] like Figures 16A to 16F As shown, it is also possible to form a through hole 10, a through hole 30, and a slit 40.

[0170] like Figure 16A As shown, firstly, in this method, a magnetic laminate 20 is fabricated. The magnetic laminate 20 has multiple wirings 2.

[0171] Next, as Figure 16B As shown, a processing stabilizing layer 24 and a second processing stabilizing layer 25 are provided in the magnetic laminate 20.

[0172] The processing stabilizing layer 24 is disposed in the second layer 16 of the magnetic layer 3, which is disposed on one side in the thickness direction. That is, the processing stabilizing layer 24 is disposed on the first main surface 6.

[0173] The second processing stabilizing layer 25 is disposed in the second layer 16 on the other side of the thickness direction in the magnetic layer 3. That is, the second processing stabilizing layer 25 is disposed on the second main surface 7.

[0174] like Figure 16C As shown, the through hole 10 and the slit 40 are formed using a sandblasting method. The through hole 10 and the slit 40 are also formed in the processing stabilizing layer 24.

[0175] Next, as Figure 16D As shown, the via 10 and the slit 40 are filled using a processing stabilizing layer 24. The material of the processing stabilizing layer 24 used for the via 10 and the slit 40 is, for example, the same as the material of the processing stabilizing layer 24 disposed on the first main surface 6.

[0176] Next, as Figure 16E As shown, a through-hole 30 is formed in a manner that exposes the wire 4. The through-hole 30 is formed, for example, by laser processing or sandblasting.

[0177] After that, as Figure 16F As shown, a conductive member 19 is formed in the through hole 30. Furthermore, in the case where the conductive member 19 is formed using chemical plating and electroplating, a decontamination (cleaning and roughening) process is performed beforehand.

[0178] The inductor 1 has multiple wirings 2, a magnetic layer 3, a processing stabilizing layer 24, a second processing stabilizing layer 25, and a conductive member 19. The inductor 1 also has a through-hole 30. Furthermore, the processing stabilizing layer 24 is filled in the slit 40. The conductive member 19 is filled in the through-hole 10.

[0179] [Effects of the 5th Embodiment]

[0180] Even after the cleaning and roughening decontamination process of the through-hole 30, the processing stabilizing layer 24 can prevent the chemical solution used in the decontamination process from contacting the magnetic layer 3. Therefore, it is possible to suppress the degradation of the function of the magnetic layer 3 caused by contact with the chemical solution.

[0181] In addition, an inductor 1 can be manufactured that includes a through hole 10 with a through hole 30, a processing stabilizing layer 24 filled into a slit 40, and a second processing stabilizing layer 25.

[0182] In addition, the inductor 1 has a processing stabilizing layer 24 disposed on the first main surface 6 and a processing stabilizing layer 25 disposed on the second main surface 7, thus enabling it to suppress warping to one side or the other side in the thickness direction.

[0183]

Example

[0184] The following examples and comparative examples further illustrate the present invention. However, the present invention is not limited to any particular example or comparative example. Furthermore, the specific numerical values ​​such as mixing ratios (including proportions), physical property values, and parameters used in the following description can replace the corresponding upper limit values ​​(values ​​defined as "less than" or "less than") or lower limit values ​​(values ​​defined as "above" or "greater than") of the mixing ratios (including proportions), physical property values, and parameters described in the "Specific Embodiments" above.

[0185] Example 1

[0186] [An embodiment corresponding to the first embodiment]

[0187] like Figure 1A and Figure 2A As shown, firstly, a magnetic stack 20 was fabricated. Specifically, a magnetic layer 3 consisting of a first magnetic sheet with a thickness of 100 μm and a second magnetic sheet with a thickness of 125 μm covered multiple wirings 2 with a radius of 115 μm.

[0188] In addition, the first magnetic sheet comprises 61.5 vol% spherical magnetic powder, 9.6 vol% cresol varnish-type epoxy resin (main agent), 9.6 vol% phenolic resin (curing agent), 0.5 vol% polyether phosphate ester (dispersant), 0.3 vol% imidazole compound (curing accelerator), and 18.5 vol% thermoplastic resin (carboxyl-containing acrylate copolymer). The second magnetic sheet comprises 55 vol% flattened magnetic particles made of Fe-Si alloy, 11.0 vol% cresol varnish-type epoxy resin (main agent), 11.0 vol% phenolic resin (curing agent), 0.4 vol% polyether phosphate ester (dispersant), 0.4 vol% imidazole compound (curing accelerator), and 21.2 vol% thermoplastic resin (carboxyl-containing acrylate copolymer).

[0189] like Figure 1B As shown, a barrier layer 21 is formed on the first main surface 6 of the insulating film 5. An opening 22 is formed in the barrier layer 21 through a photolithography process. The opening 22 is circular in shape when viewed from above. The diameter of the opening 22 is 250 μm.

[0190] like Figure 1C As shown, the through hole 10 was formed by sandblasting. The inner circumferential surface 9 of the through hole 10 has a slope 27.

[0191] The following describes the conditions for sandblasting.

[0192] Nozzle diameter: 2mm

[0193] Abrasive particles material: alumina

[0194] Median particle size of abrasive particles: 14 μm

[0195] Injection speed: 0.4 MPa

[0196] Next, as Figure 1D As shown, the barrier layer 21 was peeled off from the first main surface 6.

[0197] Thus, inductor 1 was manufactured.

[0198] Example 2

[0199] [An embodiment corresponding to the second embodiment]

[0200] like Figure 13 As shown, the inductor 1 in Embodiment 1 includes a processing stabilization layer 24 and a second processing stabilization layer 25.

[0201] Specifically, firstly, such as Figure 13As shown by the hypothetical line, two processing stabilizers 26 were prepared. The processing stabilizers 26 were formed by coating and drying a varnish comprising 935 parts by mass of spherical silica particles (first particle), 100 parts by mass of bisphenol A type epoxy resin (the main component of the thermosetting resin), 106 parts by mass of phenolic resin (curing agent), 4 parts by mass of imidazole compound (curing accelerator), and 10 parts by mass of cyclohexanone (solvent). The silica particles in the processing stabilizer 26 comprise 55% by volume. The thickness of the processing stabilizer 26 is 40 μm. The processing stabilizer 26 is in stage B.

[0202] Pressure was applied to the two processing stabilizers 26 and the inductor 1 from both sides along the thickness direction. Then, the processing stabilizers 26C were staged.

[0203] Example 3

[0204] [An embodiment corresponding to the third embodiment]

[0205] like Figure 14 As shown, through holes 30 are formed in the processing stabilization layer 24 of Example 2.

[0206] Specifically, through holes 30 were formed in the processing stabilization layer 24 by laser processing.

[0207] After that, a decontamination process is carried out, followed by, as Figure 1E As shown, after forming a seed layer (not shown) in the through-hole 30 using electroless copper plating, a conductive component 19 was formed using electroplated copper. The conductive component 19 was successfully formed.

[0208] Example 4

[0209] Except for changing the diameter of the opening 22 to 100 μm, the same treatment as in Example 1 was performed. Figure 10A As shown, the inner circumferential surface 9 has a slope 27 and a second slope 28.

[0210] Comparative Example 1

[0211] Instead of sandblasting, laser processing was used, and the process was otherwise the same as in Example 1. The wire 4 was exposed by laser processing. Furthermore, an attempt was made to form the conductive member 19 by copper electroplating. However, defects occurred in the formation of the conductive member 19.

[0212] Example 5

[0213] [An embodiment corresponding to the fourth embodiment]

[0214] As shown in Figure 15, a slit 40 is formed instead of the through-hole 10, and the number of wirings 2 is changed to 2. Otherwise, the same processing is performed as in Embodiment 1. The slit 40 penetrates the second layer 16.

[0215] Comparative Example 2

[0216] Instead of sandblasting, a cutting saw was used for cutting, and otherwise the process was the same as in Example 5.

[0217] evaluate

[0218] SEM observation and the proportion of melt-cured material M and the formation of conductive components

[0219] Cross-sectional SEM observations were performed on each of the embodiments and comparative examples. Figure 4 The image processing diagram of SEM along the second direction in Example 1 is shown. Figure 6 The image processing diagram of SEM along the second direction is shown in Comparative Example 1.

[0220] Furthermore, the percentage of the molten solidified product M was determined. The results are shown in Tables 1 and 2.

[0221] In addition, the conductive member 19 on the bottom surface 17 and inner peripheral surface 9 of the through hole 10 was observed by cross-sectional SEM images, and the formation of the conductive member 19 was evaluated according to the following criteria.

[0222] [Good] The conductive component 19 is formed without any molten solidified material M.

[0223] [Defect] The conductive component 19 is formed with molten solidified material M mixed in.

[0224] Table 1

[0225] Table 1

[0226]

[0227] Table 2

[0228] Table 2

[0229] Example 5 Sandblasting 0 Comparative Example 2 Cutting with a cutting saw 15

[0230] Furthermore, the above-described invention is provided as an illustrative embodiment of the invention, but this is merely illustrative and not intended to limit the scope of the invention. Variations of the invention that will be apparent to those skilled in the art are included in the foregoing claims.

Claims

1. A method for manufacturing an inductor, characterized in that, The manufacturing method of this inductor includes: In the first step, a magnetic laminate having wiring and a magnetic layer is fabricated. The magnetic layer embeds the wiring and contains magnetic particles. The magnetic layer has a first main surface and a second main surface. The first main surface is disposed on one side of the wiring in the thickness direction, spaced apart from the wiring. The second main surface is spaced apart from the first main surface and disposed on the opposite side of the first main surface relative to the wiring. In the second step, after the first step, a recess is formed in the magnetic layer by sandblasting, extending from the first main surface toward the second main surface. In the first step, a magnetic laminate having a plurality of said wirings is fabricated, wherein the plurality of said wirings are arranged at intervals in a direction orthogonal to both the direction in which the wirings extend and the thickness direction. In the second step, slits corresponding to the recesses are formed between the plurality of wires. When projected along the second direction, the entire inner circumferential surface of the slit is offset from the wiring on one side in the thickness direction.

2. The method for manufacturing an inductor according to claim 1, characterized in that, The second step includes: In the third step, a barrier layer having an opening corresponding to the recess is disposed on the first main surface; and In the fourth step, abrasive particles are sprayed toward the portion of the first main surface exposed from the opening.

3. A method for manufacturing an inductor, characterized in that, The manufacturing method of this inductor includes: In the first step, a magnetic laminate having wiring and a magnetic layer is fabricated. The magnetic layer embeds the wiring and contains magnetic particles. The magnetic layer has a first main surface and a second main surface. The first main surface is disposed on one side of the wiring in the thickness direction, spaced apart from the wiring. The second main surface is spaced apart from the first main surface and disposed on the opposite side of the first main surface relative to the wiring. In the second step, after the first step, a recess is formed in the magnetic layer by sandblasting, extending from the first main surface toward the second main surface. In the first step, a magnetic laminate having the wiring is fabricated, the wiring having conductors and an insulating film disposed on the periphery of the conductors. In the second step, a via corresponding to the recess is formed in the magnetic layer such that one side of the insulating film in the thickness direction is exposed. The via has an inner circumferential surface extending from the first main surface to the insulating film.

4. The method for manufacturing an inductor according to claim 3, characterized in that, The inner circumferential surface has a longest length D1 and a shortest length D2 in the surface direction orthogonal to the thickness direction at one end edge. The ratio of the longest length D1 to the shortest length D2, i.e., D1 / D2, is less than 10.

5. The method for manufacturing an inductor according to claim 3, characterized in that, The manufacturing method of the inductor also includes a step of filling the via with a processing stabilizing layer.

6. The method for manufacturing an inductor according to claim 4, characterized in that, The manufacturing method of the inductor also includes a step of filling the via with a processing stabilizing layer.

7. The method for manufacturing an inductor according to claim 5, characterized in that, The method for manufacturing the inductor also includes a step of forming a through-hole in the thickness direction that penetrates the processing stabilizing layer and the insulating film by exposing one side of the conductor in the thickness direction.

8. The method for manufacturing an inductor according to claim 6, characterized in that, The method for manufacturing the inductor also includes a step of forming a through-hole in the thickness direction that penetrates the processing stabilizing layer and the insulating film by exposing one side of the conductor in the thickness direction.

9. The method for manufacturing an inductor according to claim 7, characterized in that, The through-hole is formed by laser processing.

10. The method for manufacturing an inductor according to claim 8, characterized in that, The through-hole is formed by laser processing.

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