JP6879355B2 - Manufacturing method of coil parts - Google Patents

Description

The present invention relates to a method for manufacturing a coil component.

Conventionally, coil parts such as surface mount type flat coil elements have been widely used in electric products such as consumer equipment and industrial equipment. In particular, in small mobile devices, it has become necessary to obtain a plurality of voltages from a single power source in order to drive each device as the functions are enhanced. Therefore, surface mount type flat coil elements are also used for such power supply applications.

Such coil parts are disclosed, for example, in Patent Documents 1 to 3 below. 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, and the air core is provided by a through-hole conductor provided so as to penetrate the substrate in the magnetic core portion of the air core coil. The coils are connected to each other.

Japanese Unexamined Patent Publication No. 2006-310716 Japanese Unexamined Patent Publication No. 2012-089765 Japanese Unexamined Patent Publication No. 2013-201375

The above-mentioned air-core coil is formed by plating and growing a conductor material such as Cu on a seed pattern provided on the substrate, but the spacing between the coil winding portions is increased by the plating growth in the surface direction of the substrate. It narrows. When the interval between the winding portions of the coil is narrow, there is a concern that the insulation property of the coil may be deteriorated, so that a technique for more reliable insulation is desired.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for manufacturing a coil component capable of more reliably insulating a coil.

The method for manufacturing 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 the main surface and winding the coil component on the main surface of the substrate between the resin walls. The process includes a step of plating and growing the coil so that the rotation portion is extended, and a step of integrally covering the coil on the main surface of the substrate and the resin body with a coating resin made of a magnetic powder-containing resin.

In such a method for manufacturing a coil component, the winding portion of the coil is plated and grown so as to extend between the resin walls of the resin body provided before the coil is plated and grown. Since the resin wall is interposed between the coil windings during plating growth, the coil windings cannot come into contact with each other.

Further, the height of the resin wall of the resin body may be higher than the height of the winding portion of the coil. In this case, the wound portion can be as thick as the design dimensions in the height direction. In addition, the situation where the wound portions come into contact with each other beyond the resin wall is significantly avoided.

Further, the cross-sectional shape of the resin wall of the resin body may be rectangular. At this time, the aspect ratio of the resin wall of the resin body may be larger than 1, and the resin wall may extend long along the normal direction of the main surface of the substrate.

Further, the cross-sectional shape of the winding portion of the coil may be rectangular. At this time, the cross section of the winding portion of the coil may have an aspect ratio of more than 1, and the cross section of the winding portion may extend long along the normal direction of the main surface of the substrate.

Further, an insulator provided so as to be in contact with the upper surface of the winding portion of the coil may be further provided.

Further, among the plurality of resin walls arranged on the main surface of the substrate, the thickness of the outermost resin wall may be thicker than the thickness of the innermost resin wall.

Further, the resin wall of the resin body may have a width in the range of 5 to 30 μm and a height in the range of 50 to 300 μm.

According to the present invention, there is provided a method for manufacturing a coil component capable of more reliably insulating the coil.

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 the seed pattern of the substrate shown in FIG. FIG. 4 is a perspective view showing one step of the method for manufacturing the coil component shown in FIG. FIG. 5 is a sectional view taken along line VV of 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 for manufacturing the coil component shown in FIG. FIG. 8 is a perspective view showing one step of the method for manufacturing the coil component shown in FIG. FIG. 9 is a cross-sectional view showing a state when the coil is plated and grown 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 will be used for the same elements or elements having the same function, and duplicate description will be omitted.

First, the structure of the coil component according to the embodiment of the present invention will be described with reference to FIGS. 1 to 4. For convenience of explanation, the XYZ coordinates are set as shown in the figure. That is, the thickness direction of the flat coil element is set to the Z direction, the facing direction of the external terminal electrodes is set to the Y direction, and the direction orthogonal to the Z direction and the Y direction is set to the X direction.

The coil component 1 is composed of 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 opposite end faces of the main body portion 10. As an example, the coil component 1 is designed with dimensions of 2.0 mm on a long side, 1.6 mm on a short side, and 0.9 mm in height.

In the following, while showing the procedure for manufacturing the main body portion 10, the structure of the coil component 1 will also be described.

The main body 10 includes the substrate 11 shown in FIG. The substrate 11 is a flat plate rectangular member made of a non-magnetic insulating material. A substantially circular opening 12 is provided in the central portion of the substrate 11 so as to connect 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: a registered trademark) and a plate thickness of 60 μm can be used. In addition to BT resin, polyimide, aramid, or the like can also be used. Ceramic or glass can also be used as the material of the substrate 11. As the material of the substrate 11, a mass-produced printed circuit board material is preferable, and a resin material used for a BT printed circuit board, a FR4 printed circuit board, or an FR5 printed circuit board is most preferable.

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

In addition to the seed pattern 13A, a conduction pattern 16 is provided on each of the main surfaces 11a and 11b. When the coil 13 described later is plated and grown, the substrate 11 on which the seed pattern 13A is formed is in a wafer state. That is, a 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 the adjacent seed patterns 13A to each other. The continuity pattern 16 is for making an electrical connection thereof, and is used during plating growth, but becomes unnecessary after plating growth.

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

FIG. 4 shows the state of the substrate 11 when the coil 13 is plated and grown using the seed pattern 13A. A known plating growth method can be adopted for the plating growth of the coil 13.

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 a drawer 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 a plan view. That is, the coil 13 and the seed pattern 13A have the shape of a plane spiral air-core coil extending in parallel with the main surfaces 11a and 11b of the substrate 11. More specifically, the winding portion 14 of the upper surface surface 11a of the substrate 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 lower surface 11b of the substrate is outside when viewed from the lower surface side. It is a swirl that rotates counterclockwise along the direction toward. When a current is passed in one direction through such double-sided coils 13 in which the ends are connected to each other in the opening 12, the rotation directions in which the currents flow in both coils 13 are the same, so that the magnetic flux generated in the coils 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 sectional view taken along 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 extending long along the normal direction (Z direction) of the substrate 11 is formed on the substrate 11, and a coil is formed between the resin walls 18. The winding portion 14 of 13 grows in the Z direction. The growth region of the winding portion 14 of the coil 13 is defined in advance by the resin wall 18 formed on the substrate 11 before the plating growth. Therefore, the winding portion 14 of the coil 13 grows so as to fill the space defined between the 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 that extends 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 portion 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 portion 14 of the coil 13 may be 2 to 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 180 to 300 μm in height, 5 to 12 μm in width (thickness), and 15 to 30 in aspect ratio.

When the winding portion 14 of the coil 13 grows between two adjacent resin walls 18, it grows while being in contact with the inner side surface of the resin wall 18 that defines the growth region. At this time, neither mechanical bond nor chemical bond is generated between the winding portion 14 of the coil 13 and the resin wall 18. That is, the winding portion 14 of the coil 13 is plated and grown without being adhered to the resin wall 18, and is interposed between the resin walls 18 in a non-adhesive state. As used herein, the term "non-adhesive state" refers to a state in which a mechanical bond such as an anchor effect and a chemical bond such as a covalent bond do not occur.

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 portion 14 of the coil 13 is lower than the height H of the resin wall 18, the winding portion 14 has a thickness as designed in 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 withstand voltage resistance of the coil 13 decreases due to contact between adjacent winding portions 14 and the like. ..

Further, the thickness D of the winding portion 14 of the coil 13 is uniform over the height direction. This is because the distance between the adjacent resin walls 18 is uniform over the height direction.

Further, the top surface 14a of the winding portion 14 of the coil 13 is substantially parallel to the main surface 11a 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.

The thicknesses d1 and d2 of the resin walls 18 are also uniform over the height direction, as in the winding portion 14 of the coil 13. As a result, the distance between the winding portions 14 of the adjacent coils 13 becomes uniform over the height direction. That is, the winding portion 14 of the coil 13 has a structure in which a portion that is locally thinned in the height direction (that is, a portion where the withstand voltage resistance is locally reduced) does not exist or is unlikely to exist. There is.

Further, 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 wrap around so as to cover the upper side of the winding portion 14, the upper end portion of the winding portion 14 is above. High degree of freedom in design. That is, a mode in which an arbitrary layer is formed on the winding portion 14 or a mode in which no layer is formed can be selected.

When forming a layer on the winding portion 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 insulating property between the metallic magnetic powder contained in the coating resin 21 described later and the winding portion 14. Can be done. The insulator 40 can be made of an insulating resin or an insulating magnetic material. Further, the insulator 40 is in direct or indirect contact with 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 portion 14. Further, in order to improve the bondability between the winding portion 14 and the insulator 40, a predetermined bonding layer (for example, a blackened layer of copper plating) 41 can be provided.

Further, as shown in FIG. 5, among the plurality of resin walls 18, it is preferable that the thickness d1 of the outermost resin wall 18 is thicker than the thickness d2 of the resin wall 18 located inside (d1> d2). .. In this case, rigidity is imparted to the pressure in the Z direction received at the time of manufacturing or using the coil component 1. By arranging the thick resin wall 18 at the outermost position, the pressure is mainly received in 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 walls 18 located inside.

The plating growth of the coil 13 described above is performed on both main surfaces 11a and 11b of the substrate 11. The coils 13 of the main surfaces 11a and 11b are connected to each other at the openings of the substrate 11 and are electrically connected to each other.

After the coil 13 is plated and grown on the substrate 11, the substrate 11 is entirely covered with the coating resin 21 as shown in FIG. 7. That is, the coating resin 21 integrally covers the coils 13 of the main surfaces 11a and 11b of the substrate 11 and the resin body 17. 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, is printed on a substrate 11 in a wafer state, and is then temporarily cured to form the coating resin 21. Then, after polishing the coating resin 21 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 the metal magnetic powder is dispersed. The metal magnetic powder may be composed of, for example, an iron-nickel alloy (permalloy alloy), carbonyl iron, an amorphous, amorphous or crystalline FeSiCr-based alloy, sendust, or the like. The resin used for the metal magnetic powder-containing resin is, for example, a thermosetting epoxy resin. The content of the metal magnetic powder contained in the metal magnetic powder-containing resin is, for example, 90 to 99 wt%.

Further, the substrate 11 in the wafer state is made into a desired thickness by polishing or the like, and further diced to form chips, whereby the main body portion 10 shown in FIG. 8 can be obtained. After the chips are formed, the edges may be chamfered by barrel polishing or the like, if necessary.

Finally, the coil is provided by providing external terminal electrodes 30A and 30B on the exposed end face (end face facing in the Y direction) of the end pattern 15A of the main body 10 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 may have a multi-layer structure. For example, the external terminal electrodes 30A and 30B can be formed by applying a resin electrode material to the end face and then applying metal plating to the resin electrode material. Cr, Cu, Ni, Sn, Au, solder and the like can be used for metal plating of the external terminal electrodes 30A and 30B.

According to the coil component 1 and its manufacturing method 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 coil 14 is plated and grown. Since the resin wall 18 is interposed between the winding portions 14 of the coil 13 during plating growth, the situation where the winding portions 14 of the coil 13 come into contact with each other is avoided, and the insulation in the coil 13 is performed more reliably. Can be done. On the other hand, when the winding portion 114 is grown on the substrate 11 in the absence of the resin wall 18 described above, the shape of the winding portion 114 is not determined as shown in FIG. That is, since there is nothing that defines the plating growth region of the winding portion 114, it is difficult to obtain the shape as designed. In this case, the winding portion 114 not only grows in the height direction (longitudinal growth), but also grows in the plane direction of the substrate 11 (horizontal growth). Then, the lateral growth causes the adjacent winding portions 114 to come into contact with each other, resulting in a decrease in the withstand voltage resistance of the coil. In particular, when the winding portion 114 having a high height is to be grown, the thickness of the winding portion 114 becomes thicker due to the lateral growth, so that the withstand voltage resistance is further reduced.

Further, due to the lateral growth, the distance between the adjacent winding portions 114 becomes narrow. Therefore, it becomes difficult to fill the space between the adjacent winding portions 114 with a resin for ensuring the insulation of the winding portions 114. Even if the resin can be successfully filled between the adjacent winding portions 114, air bubbles are likely to be generated in the resin during 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 in the height direction, the withstand voltage resistance is lowered in the places where the intervals are relatively narrow.

Further, according to the coil component 1 and the manufacturing method thereof, the winding portion 14 of the coil 13 is interposed between the plurality of resin walls 18 in a non-adhesive state, so that the winding portion 14 of the coil 13 and the resin wall 18 are separated from each other. It is displaceable with respect to each other. Therefore, there is a change in the ambient temperature when the usage environment of the coil component 1 becomes high, and stress is generated due to the difference in the coefficient of thermal expansion between the winding portion 14 of the coil 13 and the resin wall 18. Even in this case, the stress is relieved by the relative movement of the winding portion 14 of the coil 13 and the resin wall 18.

Further, 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 the coil 13 is covered 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.

1 ... Coil component, 11 ... Substrate, 13 ... Coil, 14 ... Winding part, 17 ... Resin body, 18 ... Resin wall, 21 ... Coating resin, 30A, 30B ... External terminal electrode, 40 ... Insulator.

Claims (7)

A step of preparing a substrate having an opening and a resin body having a plurality of resin walls provided around the opening on the main surface, and
A step of plating and growing a coil so that a wound portion extends between the resin walls around the opening on the main surface of the substrate is included.
Of the plurality of resin walls lined up on the main surface of the substrate, the thickness of the resin wall located at the innermost side with respect to the opening is between the resin wall located at the innermost side and the resin wall located at the outermost side. A method of manufacturing coil parts that is thicker than the thickness of the resin wall on which it is located. In the step of preparing the substrate, a substrate in which a pair of the resin bodies having the plurality of resin walls are provided around the openings on both main surfaces is prepared.
Claim 1 in the step of plating and growing the coils, a pair of coils connected to each other is plated and grown so that a winding portion extends between the resin walls around the openings on both main surfaces of the substrate. The method for manufacturing coil parts described in 1. The method for manufacturing a coil component according to claim 2, further comprising a coating resin made of a magnetic powder-containing resin and integrally covering the coils on both main surfaces of the substrate and the resin bodies. The method for manufacturing a coil component according to claim 3, wherein the coating resin covers the main surface of the substrate in a region outside the resin wall located on the outermost side. The cross-sectional shape of the resin wall of the resin body is rectangular, the aspect ratio of the cross section of the resin wall of the resin body is larger than 1, and the resin wall is long along the normal direction of the main surface of the substrate. The method for manufacturing a coil component according to any one of claims 1 to 4, which is extended. The cross-sectional shape of the winding portion of the coil is rectangular, the aspect ratio of the winding portion of the coil is larger than 1, and the cross section of the winding portion is in the normal direction of the main surface of the substrate. The method for manufacturing a coil component according to any one of claims 1 to 5, which extends long along the line. The invention according to any one of claims 1 to 6, wherein the thickness of the outermost resin wall is thicker than the thickness of the innermost resin wall among the plurality of resin walls arranged on the main surface of the substrate. How to manufacture coil parts.

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