JP2017017140A - Coil component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil component that can suppress distortion and collapse of a winding portion caused by pressure from the thickness direction or surface direction of a substrate.SOLUTION: In a coil component which includes a substrate 11, a coil provided on the main surface of the substrate 11 by plating growth, a resin body which is provided on the main surface of the substrate 11 and has plural resin walls 18 between which winding portions 14 of the coil extend, and resin containing magnetic powder, the resin wall 18 has a stable cross-sectional shape in which the width d2'of the upper end portion of the resin wall 18 is larger than the width d2"of the lower end portion, and the width of the upper end portion of the winding portions 14 extending between the resin walls 18 is narrower than the width of the lower end portion. The winding portions 14 have a stable cross-sectional shape with a large cross-sectional area on the substrate 11 side. Therefore, the strength of the winding portions 14 is improved.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a coil component.

  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 a coil component is disclosed in Patent Document 1 below, for example. In the coil component disclosed in this document, a flat spiral air core coil is provided on each of the front and back surfaces of the substrate, and the air core coil is formed by a through-hole conductor provided so as to penetrate the substrate in the magnetic core portion of the air core coil. They are connected to each other.

Japanese Patent Laid-Open No. 2005-210010

  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, but the interval between the coil winding portions is increased by 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 about a decrease in the insulating property of the coil. Therefore, a technique for insulating more reliably is desired.

  In view of this, development of a technique for ensuring insulation by providing a resin wall between adjacent winding portions of a coil is underway. However, it is conceivable that a pressure from the thickness direction or the surface direction of the substrate is applied to the coil component, and the winding portion has a sufficient strength that does not cause distortion or collapse due to the pressure. Desired.

  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 the strength of a winding portion is improved.

  A coil component according to an aspect of the present invention includes a substrate, a coil provided by plating growth on the main surface of the substrate, and a plurality of resins provided on the main surface of the substrate and having a coil winding portion extending therebetween. A resin body having a wall 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, the resin wall having a width at the upper end wider than that at the lower end .

  In such a coil component, the width of the upper end portion of the resin wall is wider than the width of the lower end portion, and the width of the upper end portion is narrower than the width of the lower end portion in the winding portion extending between the resin walls. Therefore, the winding part has a stable cross-sectional shape with a large cross-sectional area on the substrate side. Therefore, the strength of the winding portion is improved, and in such a coil component, distortion and collapse of the winding portion due to pressure from the thickness direction or the surface direction of the substrate are suppressed.

  The width of the resin wall may be such that the side surface of the resin wall gradually decreases from the upper end portion toward the lower end portion so that the side surface of the resin wall becomes an inclined surface, and a step portion is formed on the side surface of the resin wall. Thus, the aspect which narrows in steps toward a lower end part from an upper end part may be sufficient.

  Moreover, the aspect whose cross-sectional shape of the resin wall of a resin body is square shape may be sufficient. At this time, the cross section of the resin wall of the resin body may be such that the ratio of the height to the length of the base is greater than 1, and the resin wall extends 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 square shape may be sufficient. At this time, the section of the coil winding portion has a ratio of the height to the length of the base larger than 1, and the section of the winding portion extends long along the normal direction of the main surface of the substrate. May be.

  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.

  Further, the resin body may be provided before the coil is plated on the main surface of the substrate, and the winding portion of the coil may not be bonded to the resin wall of the resin body.

  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.

  ADVANTAGE OF THE INVENTION According to this invention, the coil component by which the improvement of the intensity | strength of the winding part was achieved is 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 modified example of the resin wall.

  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.

  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.

  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 coil 13 is in the shape of a plane spiral air-core coil extending in parallel with the main surfaces 11a and 11b of the substrate 11 when viewed in plan, like the seed pattern 13A. 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. For example, both ends of the coils 13 on the substrate upper surface 11 a and the substrate lower surface 11 b are connected to each other through a through hole separately provided in the vicinity of the opening 12. When a current is applied to both coils 13 in one direction, the rotational directions in which the currents of both coils 13 flow are the same, so that the magnetic flux generated in the coils 13 is superimposed and strengthened.

  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.

  As shown in FIG. 5, a resin wall 18 having a rectangular cross section (trapezoidal cross section in FIG. 5) extending long along the normal direction (Z direction) of the substrate 11 is formed on the substrate 11. The winding portion 14 of the coil 13 grows in the Z direction between the resin walls 18. 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.

  The winding portion 14 of the coil 13 includes a seed portion 14a that is a part of the spiral pattern 14A and a plating portion 14b that is plated and grown on the seed portion 14a. The plating portion 14b is provided around the seed portion 14a. It is formed by gradually growing. At this time, 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. As a result, the winding portion 14 of the coil 13 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.

  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.

  The resin wall 18 has a rectangular cross section (a trapezoidal cross section in which the lower base is shorter than the upper base in FIG. 5), and the width d2 'at the upper end is wider than the width d2' 'at the lower end. The resin wall 18, more specifically, the side wall 18a of the resin wall 18 is gradually narrowed from the upper end portion toward the lower end portion so as to be an inclined surface. The cross-sectional dimensions of the resin wall 18 are, for example, 50 to 300 μm in height, 5 to 30 μm in width (thickness) at the upper end, 5 to 30 μm in width (thickness) at the lower end, and high relative to the width (bottom) at the lower end. The ratio is 5-30. The cross-sectional dimensions of the resin wall 18 are 180 to 300 μm in height, 5 to 12 μm in width (thickness) at the upper end, 5 to 12 μm in width (thickness) at the lower end, and 15 to 30 in height ratio to the width of the lower end. It may be. Note that the width d2 ″ of the lower end portion of the resin wall 18 may be 80% to 30% of the width d2 ′ on the upper end side. Increasing the width d2 'of the upper end portion of the resin wall 18 relative to the width d2 "of the lower end portion can be realized by adjusting, for example, exposure conditions of photolithography.

  As shown in FIG. 5, the winding portion 14 of the coil 13 has a trapezoidal cross section in which the lower base is longer than the upper base, and the cross-sectional dimensions thereof are, for example, a height of 80 to 260 μm and a width (thickness) of 40. ˜260 μm, the ratio of the height to the width (base) of the lower end is 1 to 5. The ratio of the height to the width of the lower end portion of the winding portion 14 of the coil 13 may be 2 to 5.

  Furthermore, as shown in FIG. 5, the upper surface 14c of the winding part 14 of the coil 13 has a shape protruding upward. More specifically, the upper surface 14c of the winding portion 14 of the coil 13 is substantially parallel to the main surface 11a of the substrate 11 at the center, but gradually falls in a curved shape at the end near the resin wall 18. ing. And in the upper surface 14c of the winding part 14 of the coil 13, with respect to the relative position with respect to the main surface 11a of the board | substrate 11, the height position which contact | connects the resin wall 18 of the upper surface 14c is the highest height located in the center part of the upper surface 14c. It is lower than the position.

  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, when 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 or the thickness of the insulator 40 and the bonding layer 41 described later is set. This is because a situation occurs in which the sufficient resistance cannot be secured and the withstand voltage resistance of the coil 13 is reduced.

  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 is in direct or indirect contact with the upper surface 14c 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 by oxidation) 41 can be provided in order to improve the bonding property between the winding portion 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, formed on the substrate 11 in a wafer state, and then 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 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 described above, as shown in FIG. 5, the width d2 ′ of the upper end portion of the resin wall 18 is wider than the width d2 ″ of the lower end portion, and the winding portion 14 extending between the resin walls 18 The width of the upper end is narrower than the width of the lower end. Therefore, the winding part 14 has a stable cross-sectional shape with a large cross-sectional area on the substrate 11 side. Therefore, the strength of the winding part 14 is improved, and in such a coil component 1, the thickness of the substrate 11 (vertical direction in FIG. 5) and the surface direction (horizontal direction in FIG. 5) are reduced. Distortion and collapse of the winding part 14 due to pressure are suppressed.

  In particular, since the resin wall 18 is gradually narrowed from the upper end portion toward the lower end portion so that the side surface 18a becomes an inclined surface, the winding portion 14 is placed at any position on the side surface when stress is applied. The stress is less likely to concentrate. For this reason, the winding portion 14 is further improved in strength against pressure from the thickness direction or the surface direction of the substrate 11.

  Further, since the width d2 ′ of the upper end portion of the resin wall 18 is wider than the width d2 ″ of the lower end portion, the upper opening of the space defined between the two adjacent resin walls 18 is narrowed. It is illustrated. In other words, the upper end portion of the resin wall 18 projects over the space, and the upper end portion of the resin wall 18 partially covers the space. Therefore, when the winding part 14 of the coil 13 is plated and grown inside the space, a situation where the plating part 14b overflows from the space is suppressed, and as a result, a situation where a short circuit occurs between the winding parts 14 is also suppressed. Is done.

  Further, since the width d2 ″ of the lower end portion of the resin wall 18 is narrower than the width d2 ′ of the upper end portion, the space defined between the two adjacent resin walls 18 has a wide bottom area. Therefore, the width of the seed portion 14a can be expanded while ensuring a sufficient clearance between the side surface of the lower end portion of the resin wall 18 and the seed portion 14a. When the width of the seed part 14a is increased, the joining region between the seed part 14a and the plating part 14b is increased accordingly, so that the joining strength between the coil 13 and the substrate 11 is improved.

  Moreover, according to the coil component 1, the height position where the upper surface 14c of the winding part 14 of the coil 13 is in contact with the resin wall 18 is lower than the highest height position on the upper surface 14c. Therefore, the creeping distance from the winding part 14 to the adjacent winding part 14 via the resin wall 18 is extended, and the pressure resistance is improved between the adjacent winding parts 14.

  Furthermore, according to the coil component 1, 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 displaced relative to each other. Is possible. 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.

  Moreover, according to the manufacturing method of the coil component 1, 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.

  The coil component 1 is not limited to the above-described form, and various forms can be adopted.

  For example, the cross-sectional shape of the resin wall may be a cross-sectional shape as shown in FIG. The resin wall 18A shown in FIG. 9 is gradually narrowed from the upper end portion toward the lower end portion so that the step portion 18b is formed on the side surface 18a. Similarly to the above-described resin wall 18, the resin wall 18 </ b> A has a width d <b> 2 ′ at the upper end wider than a width d <b> 2 ″ at the lower end, and the winding portion 14 extending between the resin walls 18 has a width at the upper end. It is narrower than the width. Therefore, the winding portion 14 is improved in strength, and in such a coil component 1, the thickness of the substrate 11 (up and down direction in FIG. 8) and the surface direction (left and right direction in FIG. 8) are reduced. Distortion and collapse of the winding part 14 due to pressure are suppressed.

  DESCRIPTION OF SYMBOLS 1 ... Coil component, 11 ... Board | substrate, 13 ... Coil, 14 ... Winding part, 14a ... Seed part, 14b ... Plating part, 14c ... Upper surface, 17 ... Resin body 18, 18A ... Resin wall, 18a ... Side surface, 18b ... Step part, 21 ... Coating 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 between which the coil winding portion extends;
A magnetic powder-containing resin, and a coating resin that integrally covers the coil and the resin body on the main surface of the substrate;
The resin wall is a coil component in which an upper end portion is wider than a lower end portion.   2. The coil component according to claim 1, wherein the width of the resin wall gradually decreases from an upper end portion toward a lower end portion so that a side surface of the resin wall becomes an inclined surface.   2. The coil component according to claim 1, wherein the width of the resin wall gradually decreases from an upper end portion toward a lower end portion so that a step portion is formed on a side surface of the resin wall.   The coil component as described in any one of Claims 1-3 whose cross-sectional shape of the resin wall of the said resin body is square shape.   The cross section of the resin wall of the resin body has a ratio of the height to the length of the base larger than 1, and the resin wall extends long along the normal direction of the main surface of the substrate. Coil parts.   The coil component as described in any one of Claims 1-5 whose cross-sectional shape of the winding part of the said coil is square shape.   The cross section of the winding part of the coil has a ratio of the height to the length of the base larger than 1, and the cross section of the winding part extends long along the normal direction of the main surface of the substrate. Coil parts as described in.   The coil component according to any one of claims 1 to 7, wherein a height of a resin wall of the resin body is higher than a height of a winding portion of the coil. The resin body is provided before the coil is plated on the main surface of the substrate,
The coil part according to any one of claims 1 to 8, wherein the winding portion of the coil is not bonded to the resin wall of the resin body.   10. The resin wall according to claim 1, wherein a thickness of the outermost resin wall among a plurality of resin walls arranged on the main surface of the substrate is thicker than a thickness of the resin wall located on the inner side. Coil parts.

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