JP2016103592A - Coil component and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil component in which stress distortion is suppressed, and a manufacturing method of the same.SOLUTION: In a coil component 1 and a manufacturing method of the same, as a wound part 14 of a coil 13 is interposed between a plurality of resin walls 18 in a non-adhesive state, the wound part 14 of the coil 13 and the resin wall 18 can be displaced from each other. Even when a peripheral temperature is changed because use environment of the coil component 1 has a high temperature, for example, and stress is caused due to difference of thermal expansion coefficients between the wound part 14 of the coil 13 and the resin wall 18, the stress is alleviated by relative displacement of the wound part 14 of the coil 13 and the resin wall 18.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a coil component and a manufacturing method thereof.

  Conventionally, coil components such as surface-mount type planar coil elements have been widely used in electrical products such as consumer equipment and industrial equipment. In particular, in small portable devices, as functions are enhanced, it is necessary to obtain a plurality of voltages from a single power source in order to drive each device. Therefore, surface mount type planar coil elements are also used for such power supply applications.

  Such coil components are disclosed in, for example, the following Patent Documents 1 to 3. In the coil components disclosed in these documents, plane spiral air core coils are provided on the front and back surfaces of the substrate, respectively. The coils are connected.

JP 2006-310716 A JP 2012-089765 A JP 2013-201375 A

  The above-described air-core coil is formed by plating and growing a conductor material such as Cu on a seed pattern provided on a substrate. After plating and growing, the coil is covered with an insulating resin and the insulating resin is cured. The The coil covered with the insulating resin is firmly bonded to the insulating resin. When the ambient temperature changes (for example, when the environment becomes high temperature), stress is generated due to the difference in thermal expansion coefficient between the coil and the insulating resin, but the insulating resin and the coil are firmly bonded. If it is, the stress is difficult to be relaxed and stress distortion may occur.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a coil component in which stress distortion is suppressed and a manufacturing method thereof.

  A coil component according to one aspect of the present invention is provided on a substrate, a coil provided by plating growth on the main surface of the substrate, and provided on the main surface of the substrate, and the winding portion of the coil is not bonded. A resin body having a plurality of resin walls interposed therebetween, and a coating resin made of a magnetic powder-containing resin and integrally covering the coil on the main surface of the substrate and the resin body.

  In such a coil component, since the coil winding portion is interposed between the plurality of resin walls in a non-adhered state, the coil winding portion and the resin wall can be displaced with respect to each other. Therefore, even if there is a change in the ambient temperature and a stress is caused by the difference in thermal expansion coefficient between the coil winding portion and the resin wall, the coil winding portion and the resin wall are relatively The stress is relieved by moving.

  Moreover, the aspect whose resin wall height of a resin body is higher than the height of the winding part of a coil may be sufficient. In this case, the winding portion can have a thickness according to the design dimension over the height direction. Moreover, the situation where winding parts contact | connect over a resin wall is significantly avoided.

  Moreover, the aspect whose cross-sectional shape of the resin wall of a resin body is a rectangular shape may be sufficient. At this time, the aspect ratio of the resin wall of the resin body may be greater than 1, and the resin wall may extend long along the normal direction of the main surface of the substrate.

  Moreover, the aspect whose cross-sectional shape of the winding part of a coil is a rectangular shape may be sufficient. At this time, the cross section of the winding portion of the coil may have an aspect ratio greater than 1, and the cross section of the winding portion may extend long along the normal direction of the main surface of the substrate.

  Moreover, the aspect further provided with the insulator provided so that the upper surface of the winding part of a coil may be sufficient may be sufficient.

  Further, among the resin walls arranged on the main surface of the substrate, the outermost resin wall may be thicker than the resin wall located inside.

  Further, the resin wall of the resin body may have an aspect in which the width is in the range of 5 to 30 μm and the height is in the range of 30 to 300 μm.

  A coil component according to one aspect of the present invention includes a step of preparing a substrate in which a resin body having a plurality of resin walls is provided on a main surface, and a winding portion between the resin walls on the main surface of the substrate. A step of plating and growing the coil so as to intervene in a non-adhered state, and a step of integrally covering the coil and the resin body on the main surface of the substrate with a coating resin made of a magnetic powder-containing resin.

  According to the present invention, a coil component in which stress strain is suppressed and a method for manufacturing the same are provided.

FIG. 1 is a schematic perspective view of a coil component according to an embodiment of the present invention. FIG. 2 is a perspective view showing a substrate used for manufacturing the coil component shown in FIG. FIG. 3 is a plan view showing a seed pattern of the substrate shown in FIG. FIG. 4 is a perspective view showing one step of the method of manufacturing the coil component shown in FIG. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a cross-sectional view showing an insulator provided on the winding portion of the coil. FIG. 7 is a perspective view showing one step of the method of manufacturing the coil component shown in FIG. FIG. 8 is a perspective view showing one step of the method of manufacturing the coil component shown in FIG. FIG. 9 is a cross-sectional view showing a state in which a coil is grown by plating in the prior art.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  First, the structure of the coil component according to the embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, XYZ coordinates are set as shown. That is, the thickness direction of the planar coil element is set as the Z direction, the facing direction of the external terminal electrode is set as the Y direction, and the direction orthogonal to the Z direction and the Y direction is set as the X direction.

  The coil component 1 includes a main body portion 10 having a substantially rectangular parallelepiped shape and a pair of external terminal electrodes 30A and 30B provided so as to cover a pair of opposed end faces of the main body portion 10. As an example, the coil component 1 is designed with dimensions of a long side of 2.0 mm, a short side of 1.6 mm, and a height of 0.9 mm.

  Below, while showing the procedure of producing the main-body part 10, the structure of the coil component 1 is also demonstrated.

  The main body 10 includes a substrate 11 shown in FIG. The substrate 11 is a flat rectangular member made of a nonmagnetic insulating material. A substantially circular opening 12 is provided in the center portion of the substrate 11 so as to pass through the main surfaces 11a and 11b. As the substrate 11, a substrate in which a glass cloth is impregnated with a cyanate resin (BT (bismaleimide / triazine) resin: registered trademark) having a plate thickness of 60 μm can be used. In addition to BT resin, polyimide, aramid, etc. can also be used. As the material of the substrate 11, ceramic or glass can be used. The material of the substrate 11 is preferably a mass-produced printed circuit board material, and most preferably a resin material used for a BT printed circuit board, FR4 printed circuit board, or FR5 printed circuit board.

  As shown in FIG. 3, a seed pattern 13A for plating growth of a coil 13 described later is formed on the main surface 11a, 11b of the substrate 11, as shown in FIG. The seed pattern 13A has a spiral pattern 14A that turns around the opening 12 of the substrate 11, and an end pattern 15A that is formed at the end of the substrate 11 in the Y direction, and these patterns 14A, 15A are continuous and It is integrally formed. The coil 13 provided on the one main surface 11a side and the coil 13 provided on the other main surface 11b side have opposite electrode drawing directions, so that the end pattern 15A on the one main surface 11a side and the other The end pattern on the main surface 11b side is formed at different end portions of the substrate 11 in the Y direction.

  In addition to the seed pattern 13A, a conductive pattern 16 is provided on each main surface 11a, 11b. When the later-described coil 13 is plated and grown, the substrate 11 on which the seed pattern 13A is formed is in a wafer state. That is, the plurality of seed patterns 13A are regularly arranged on the surface of the substrate wafer. In such a state, in order to apply a voltage to each of the plurality of seed patterns 13A, it is necessary to electrically connect adjacent seed patterns 13A. The conductive pattern 16 is for electrical connection and is used during plating growth, but is unnecessary after plating growth.

  Returning to FIG. 2, a resin body 17 is provided on each main surface 11 a, 11 b of the substrate 11. The resin body 17 is a thick film resist patterned by known photolithography. The resin body 17 includes a resin wall 18 that defines the growth region of the winding portion 14 of the coil 13 and a resin wall 19 that defines the growth region of the extraction electrode portion 15 of the coil 13. The resin body 17 is also disposed on the conductive pattern 16 described above, and also has a resin wall 20 for preventing plating growth in the conductive pattern 16.

  FIG. 4 shows the state of the substrate 11 when the coil 13 is grown by plating using the seed pattern 13A. For plating growth of the coil 13, a known plating growth method can be employed.

  The coil 13 is made of copper, and has a winding portion 14 formed on the spiral pattern 14A of the seed pattern 13A and an extraction electrode portion 15 formed on the end pattern 15A of the seed pattern 13A. ing. The shape of the coil 13 is substantially the same as the shape of the seed pattern 13A when viewed in plan. That is, the coil 13 and the seed pattern 13 </ b> A have a shape of a plane spiral air-core coil that extends in parallel to the main surfaces 11 a and 11 b of the substrate 11. More specifically, the winding portion 14 of the substrate upper surface 11a is a spiral that rotates counterclockwise along the direction toward the outside when viewed from the upper surface side, and the winding portion 14 of the substrate lower surface 11b is the outer surface when viewed from the lower surface side. It is a swirl that rotates counterclockwise along the direction toward. When current flows in one direction through such a double-sided coil 13 whose ends are connected to each other in the opening 12, the rotational direction in which the current flows in both coils 13 is the same, so that the magnetic flux generated in the coil 13 is superimposed. And strengthen each other.

  FIG. 5 shows a state of the substrate 11 after the plating growth shown in FIG. 4, and is a cross-sectional view taken along the line VV of FIG. In FIG. 5, the seed pattern 13A is not shown.

  As shown in FIG. 5, a resin wall 18 having a rectangular cross section that extends long along the normal direction (Z direction) of the substrate 11 is formed on the substrate 11, and a coil is interposed between these resin walls 18. Thirteen winding portions 14 grow in the Z direction. The growth region of the winding portion 14 of the coil 13 is defined in advance by a resin wall 18 formed on the substrate 11 before plating growth. Therefore, the winding portion 14 of the coil 13 grows so as to fill a space defined between two adjacent resin walls 18 and has the same shape as the space defined between the resin walls 18. It is formed and has a shape extending long along the normal direction (Z direction) of the substrate 11. That is, by adjusting the shape of the space defined between the resin walls 18, the shape of the winding portion 14 of the coil 13 is adjusted, and the winding portion 14 of the coil 13 is formed in the shape as designed. be able to. The cross-sectional dimensions of the winding part 14 of the coil 13 are, for example, a height of 80 to 260 μm, a width (thickness) of 40 to 260 μm, and an aspect ratio of 1 to 5. The aspect ratio of the winding part 14 of the coil 13 may be 2-5. The cross-sectional dimensions of the resin wall 18 are, for example, a height of 50 to 300 μm, a width (thickness) of 5 to 30 μm, and an aspect ratio of 5 to 30. The cross-sectional dimensions of the resin wall 18 may be a height of 180 to 300 μm, a width (thickness) of 5 to 12 μm, and an aspect ratio of 15 to 30.

  When the winding portion 14 of the coil 13 grows between two adjacent resin walls 18, it grows in contact with the inner surface of the resin wall 18 that defines the growth region. At this time, neither mechanical bonding nor chemical bonding occurs between the winding portion 14 of the coil 13 and the resin wall 18. That is, the winding part 14 of the coil 13 is plated and grown without being bonded to the resin wall 18 and is interposed between the resin walls 18 in a non-bonded state. In the present specification, the “non-adhesion state” refers to a state where no mechanical bond such as an anchor effect or chemical bond such as a covalent bond occurs.

  As shown in FIG. 5, the height h of the winding portion 14 of the coil 13 is preferably lower than the height H of the resin wall 18 (h <H). That is, it is preferable to adjust so that the plating growth of the winding portion 14 of the coil 13 stops at a position lower than the height H of the resin wall 18. When the height h of the winding part 14 of the coil 13 is lower than the height H of the resin wall 18, the winding part 14 has a thickness as designed across the height direction. Further, if the height h of the winding portion 14 of the coil 13 is higher than the height H of the resin wall 18, the adjacent winding portions 14 come into contact with each other, and the withstand voltage resistance of the coil 13 decreases. .

  Moreover, the thickness D of the winding part 14 of the coil 13 is uniform over the height direction. This is because the interval between the adjacent resin walls 18 is uniform over the height direction.

  Furthermore, the top surface 14 a of the winding portion 14 of the coil 13 is substantially parallel to the main surface 11 a of the substrate 11. This is because the winding portion 14 of the coil 13 grows while the top surface is kept parallel to the main surface 11a of the substrate 11 during plating growth.

  It should be noted that the thicknesses d1 and d2 of the resin walls 18 are also uniform in the height direction, like the winding part 14 of the coil 13. As a result, the interval between the winding portions 14 of the adjacent coils 13 is uniform over the height direction. That is, the winding portion 14 of the coil 13 has a structure in which there is no or a portion that is locally thin in the height direction (that is, a portion where the withstand voltage resistance is locally reduced). Yes.

  Moreover, since the upper end of the space defined by the resin wall 18 is open and the upper end portion of the resin wall 18 does not go around so as to cover the upper side of the winding portion 14, High design freedom. That is, an aspect in which an arbitrary layer is formed on the winding portion 14 or an aspect in which no layer is formed can be selected.

  When forming a layer on the winding part 14, various layer forms and layer materials can be selected. For example, as shown in FIG. 6, an insulator 40 is provided on the winding portion 14 in order to improve the insulation between the metal magnetic powder contained in the coating resin 21 described later and the winding portion 14. Can do. The insulator 40 can be made of an insulating resin or an insulating magnetic material. The insulator 40 directly or indirectly contacts the upper surface 14a of the winding portion 14 and integrally covers the winding portion 14 and the resin wall 18. The insulator 40 may be configured to selectively cover only the winding part 14. In addition, a predetermined bonding layer (for example, a blackened layer of copper plating) 41 can be provided in order to improve the bonding property between the winding part 14 and the insulator 40.

  Furthermore, as shown in FIG. 5, it is preferable that the thickness d1 of the outermost resin wall 18 among the plurality of resin walls 18 is thicker than the thickness d2 of the resin wall 18 positioned inside (d1> d2). . In this case, rigidity is imparted to the pressure in the Z direction that is received when the coil component 1 is produced or used. By placing the thick resin wall 18 at the outermost position, the pressure is mainly received at this portion. From the viewpoint of rigidity, it is preferable that both of the resin walls 18 located at both ends are thicker than the thickness of the resin wall 18 located inside.

  Note that the above-described plating growth of the coil 13 is performed on both main surfaces 11 a and 11 b of the substrate 11. The coils 13 on both main surfaces 11a and 11b are electrically connected to each other at their ends in the opening of the substrate 11.

  After the coil 13 is plated and grown on the substrate 11, the substrate 11 is entirely covered with a coating resin 21 as shown in FIG. That is, the coating resin 21 integrally covers the coil 13 and the resin body 17 on the main surfaces 11 a and 11 b of the substrate 11. The resin body 17 constitutes a part of the coil component 1 while remaining in the coating resin 21. The coating resin 21 is made of a metal magnetic powder-containing resin, and is formed by printing on the substrate 11 in a wafer state and then temporarily curing. Then, after the coating resin 21 is polished to a predetermined thickness, the coating resin 21 is further cured.

  The metal magnetic powder-containing resin constituting the coating resin 21 is composed of a resin in which metal magnetic powder is dispersed. The metal magnetic powder can be composed of, for example, iron-nickel alloy (permalloy alloy), carbonyl iron, amorphous, amorphous or crystalline FeSiCr alloy, sendust, and the like. The resin used for the metal magnetic powder-containing resin is, for example, a thermosetting epoxy resin. As an example, the content of the metal magnetic powder contained in the metal magnetic powder-containing resin is 90 to 99 wt%.

  Furthermore, the main body 10 shown in FIG. 8 is obtained by forming the wafer-like substrate 11 to a desired thickness by polishing or the like, and further dicing into chips. After forming the chip, the edge may be chamfered by barrel polishing or the like as necessary.

  Finally, the external terminal electrodes 30A and 30B are provided on the end face (end face facing in the Y direction) from which the end pattern 15A of the main body part 10 is exposed so as to be electrically connected to the end pattern 15A. Part 1 is completed. The external terminal electrodes 30A and 30B are electrodes for connecting to a circuit of a substrate on which a coil component is mounted, and can have a multi-layer structure. For example, the external terminal electrodes 30 </ b> A and 30 </ b> B can be formed by applying a resin electrode material to the end surfaces and then performing metal plating on the resin electrode material. Cr, Cu, Ni, Sn, Au, solder, etc. can be used for metal plating of the external terminal electrodes 30A, 30B.

  According to the coil component 1 and the manufacturing method thereof described above, as shown in FIG. 5, the coil 13 is wound so as to extend between the resin walls 18 of the resin body 17 provided before the coil 13 is plated and grown. The turning part 14 is plated and grown. Since the resin wall 18 is interposed between the winding portions 14 of the coil 13 during plating growth, a situation where the winding portions 14 of the coil 13 are in contact with each other is avoided, and insulation in the coil 13 is more reliably performed. Can do. On the other hand, when the winding part 114 is grown on the substrate 11 without the resin wall 18 described above, the shape of the winding part 114 is not fixed as shown in FIG. That is, since there is no thing that defines the plating growth region of the winding part 114, it is difficult to obtain the shape as designed. In this case, the wound portion 114 not only grows in the height direction (vertical growth) but also grows in the plane direction of the substrate 11 (lateral growth). Then, by laterally growing, adjacent winding portions 114 come into contact with each other, and the breakdown voltage resistance of the coil is reduced. In particular, when trying to grow the winding part 114 having a high height, the thickness of the winding part 114 is increased due to the lateral growth, so that the breakdown voltage resistance is further reduced.

  Moreover, the space | interval of adjacent winding parts 114 becomes narrow by laterally growing. Therefore, it becomes difficult to fill a resin between the adjacent winding portions 114 for ensuring insulation of the winding portions 114. Even if the resin can be satisfactorily filled between the adjacent winding portions 114, bubbles are likely to be generated in the resin at the time of filling, so that a necessary and sufficient withstand voltage resistance may not be obtained.

  In addition, since the intervals between the adjacent winding portions 114 are different with respect to the height direction, the withstand voltage resistance is lowered at locations where the intervals are relatively narrow.

  Furthermore, according to the coil component 1 and the manufacturing method thereof, since the winding part 14 of the coil 13 is interposed between the plurality of resin walls 18 in a non-adhered state, the winding part 14 of the coil 13 and the resin wall 18 are Displaceable relative to each other. Therefore, there is a change in the ambient temperature such as when the usage environment of the coil component 1 is high, and stress is generated due to the difference in the thermal expansion coefficient between the winding portion 14 of the coil 13 and the resin wall 18. Even if it is a case, the stress is relieved because the winding part 14 of the coil 13 and the resin wall 18 move relatively.

  Furthermore, according to the coil component 1 and the manufacturing method thereof, the winding portion 14 of the coil 13 is plated and grown so as to be interposed between the resin walls 18 of the resin body 17. That is, before covering the coil 13 with the coating resin 21, the resin wall 18 is already interposed between the winding portions 14 of the coil 13. Therefore, it is not necessary to separately fill the resin between the winding portions 14 of the coil 13, and the resin wall 18 stabilizes the dimensional accuracy of the resin between the winding portions 14 of the coil 13.

  DESCRIPTION OF SYMBOLS 1 ... Coil component, 11 ... Board | substrate, 13 ... Coil, 14 ... Winding part, 17 ... Resin body, 18 ... Resin wall, 21 ... Cover resin, 30A, 30B ... External terminal electrode, 40 ... Insulator.

Claims (10)

A substrate,
A coil provided by plating growth on the main surface of the substrate;
A resin body provided on the main surface of the substrate and having a plurality of resin walls interposed between the coil winding portions in a non-adhered state;
A coil component comprising a resin containing magnetic powder and comprising a coating resin that integrally covers the coil and the resin body on the main surface of the substrate.   The coil component according to claim 1, wherein a height of a resin wall of the resin body is higher than a height of a winding portion of the coil.   The coil component according to claim 1 or 2, wherein the resin wall of the resin body has a rectangular cross-sectional shape.   The coil component according to claim 3, wherein an aspect ratio of the resin wall of the resin body is greater than 1, and the resin wall extends long along a normal direction of the main surface of the substrate.   The coil component according to any one of claims 1 to 4, wherein a cross-sectional shape of a winding portion of the coil is a rectangular shape.   6. The coil component according to claim 5, wherein a cross-section of the winding portion of the coil has an aspect ratio larger than 1, and the cross-section of the winding portion extends long along the normal direction of the main surface of the substrate.   The coil component as described in any one of Claims 1-6 further provided with the insulator provided so that the upper surface of the winding part of the said coil may be contact | connected.   The coil according to any one of claims 1 to 7, wherein, among a plurality of resin walls arranged on the main surface of the substrate, the outermost resin wall is thicker than the resin wall located on the inner side. parts.   The coil component according to any one of claims 1 to 8, wherein the resin wall of the resin body has a width in a range of 5 to 30 µm and a height in a range of 50 to 300 µm. Preparing a substrate provided with a resin body having a plurality of resin walls on a main surface;
A step of plating and growing a coil on the main surface of the substrate such that a winding portion is interposed between the resin walls in a non-adhered state; and
A method of manufacturing a coil component, including a step of integrally covering the coil and the resin body on a main surface of the substrate with a coating resin made of a magnetic powder-containing resin.

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