JP6520480B2 - Coil parts - Google Patents

Description

  The present invention relates to a coil component.

  2. Description of the Related Art Conventionally, coil components such as surface-mounted flat coil elements are widely used in electric products such as consumer devices and industrial devices. Above all, in the case of small portable devices, it is necessary to obtain a plurality of voltages from a single power source to drive each device as the functions are enhanced. Then, the surface mounting type planar coil element is used also for such a power supply application etc.

  Such a coil component is disclosed, for example, in Patent Document 1 below. In the coil component disclosed in this document, the air core coil is provided by providing through-hole conductors provided on the front and back surfaces of the substrate with planar spiral air core coils and penetrating the substrate in the core portion of the air core coil. Are connected to each other.

JP, 2005-21010, A

  The air core coil described above is formed by plating and growing a conductive material such as Cu on a seed pattern provided on the substrate, but the plating growth in the surface direction of the substrate causes the distance between the winding portions of the coil to It narrows. In the case where the distance between the winding portions of the coil is narrow, there is a concern that the insulation of the coil may deteriorate, and therefore, a technique for more reliable insulation is desired.

  Therefore, development of technology for achieving reliable insulation by providing a resin wall between adjacent winding portions of a coil has been advanced. However, in the case where the resin wall is provided separately from the substrate, it is conceivable that the pressure resistance of the bonding surface between the resin wall and the substrate is lower than that at other portions. Therefore, in order to realize a high dielectric breakdown voltage between the winding parts, improvement of the breakdown voltage at the joint surface is required.

  The present invention was made in order to solve the above-mentioned subject, and an object of the present invention is to provide a coil component in which pressure resistance improvement between winding parts was aimed at.

  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 a plurality of resins provided on the main surface of the substrate, with the coil winding portion extending therebetween A resin body having a wall, and a covering resin made of a magnetic powder-containing resin and integrally covering the coil of the main surface of the substrate and the resin body, the lower end portion of the resin wall of the winding portion is the main surface of the substrate It is separated from the joint surface to be joined.

  In such a coil component, since the winding portion is separated from the bonding surface between the lower end portion of the resin wall and the main surface of the substrate, the winding portions adjacent to each other via the resin wall are in the vicinity of the bonding surface I am away. Thereby, the withstand voltage improvement between winding parts is achieved by the short circuit via the said joint surface being suppressed.

  In addition, an air gap may be present between the winding portion and the bonding surface, and the winding portion may be separated from the bonding surface via the air gap.

  Also, the air gap may be in a form having a cross-sectional shape including a wedge portion which gets under the winding portion.

  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 have an aspect in which the ratio of the height to the length of the base is larger than 1 and the resin wall extends long along the normal direction of the main surface of the substrate. .

  Moreover, the cross-sectional shape of the winding part of a coil may be a square-shaped aspect. At this time, the section of the winding portion of the coil has a ratio of the height to the length of the base greater than 1, and the cross section of the winding portion is elongated along the normal direction of the main surface of the substrate. May be

  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 winding portion can have a thickness as designed over the height direction. Moreover, the situation in which the wound portions contact with each other beyond the resin wall is significantly avoided.

  The resin body may be provided before the coil is plated and grown 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.

  In addition, of the plurality of resin walls arranged on the main surface of the substrate, the thickness of the resin wall positioned outermost may be thicker than the thickness of the resin wall positioned inside.

  According to the present invention, there is provided a coil component in which the withstand voltage between the winding portions is improved.

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. FIG. 5 is a cross-sectional view taken along line V-V of FIG. FIG. 6 is an enlarged view of an essential part showing the vicinity of the bonding surface between the resin wall and the substrate. FIG. 7 is a cross-sectional view showing the insulator provided on the winding portion of the coil. FIG. 8 is a perspective view showing one step of a method of manufacturing the coil component shown in FIG. FIG. 9 is a perspective view showing one step of the method of manufacturing the coil component shown in FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same elements or elements having the same function will be denoted by the same reference symbols, without redundant description.

  First, the structure of a coil component according to an embodiment of the present invention will be described with reference to FIGS. For convenience of explanation, XYZ coordinates are set as illustrated. 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 is configured 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 opposing end surfaces of the main body portion 10. The coil component 1 is, for example, designed to have dimensions of a long side of 2.0 mm, a short side of 1.6 mm, and a height of 0.9 mm.

  Below, the structure of the coil component 1 is also demonstrated, showing the procedure which produces the main-body part 10 collectively.

  The main body 10 includes the substrate 11 shown in FIG. The substrate 11 is a flat rectangular member made of a nonmagnetic insulating material. In the central portion of the substrate 11, a substantially circular opening 12 is provided so as to connect the main surfaces 11a and 11b. The substrate 11 may be a substrate in which glass cloth is impregnated with cyanate resin (BT (bismaleimide triazine) resin: registered trademark), and the one having 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. 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 board, an FR4 printed board, or an FR5 printed board.

  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 turns 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 integrally formed. In addition, the electrode drawing direction is opposite between the coil 13 provided on the one main surface 11 a side and the coil 13 provided on the other main surface 11 b side, so the end pattern 15 A on the one main surface 11 a side and the other The end patterns on the main surface 11 b side of the substrate 11 are formed at different ends of the substrate 11 in the Y direction.

  Returning to FIG. 2, resin bodies 17 are provided on the main surfaces 11 a and 11 b of the substrate 11. The resin body 17 is a thick film resist patterned by known photolithography. The resin body 17 has a resin wall 18 which defines a growth region of the winding portion 14 of the coil 13 and a resin wall 19 which defines a growth region of the lead-out 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. 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 lead electrode portion 15 formed on the end pattern 15A of the seed pattern 13A. ing. The coil 13 has a flat spiral spiral core shape extending parallel to the main surfaces 11 a and 11 b of the substrate 11 as seen from above, like the seed pattern 13 A, in plan view. More specifically, the winding portion 14 of the substrate upper surface 11a is a left-handed spiral along the direction toward the outer side when viewed from the upper surface side, and the winding portion 14 of the substrate lower surface 11b is the outer side when viewed from the lower surface It is a spiral of left rotation along the direction towards. The end portions of both the coils 13 of the substrate upper surface 11a and the substrate lower surface 11b are connected to each other through a through hole separately provided in the vicinity of the opening 12, for example. When current flows in one direction in both coils 13, the rotation direction of the current in both coils 13 is the same, so the magnetic fluxes generated in the coils 13 overlap and strengthen each other.

  FIG. 5 shows the state of the substrate 11 after the plating growth shown in FIG. 4 and is a cross-sectional view taken along the line V-V in FIG.

  As shown in FIG. 5, on the substrate 11, resin walls 18 having a rectangular cross section (a rectangular cross section in FIG. 5) extending along the normal direction (Z direction) of the substrate 11 are formed. The wound portion 14 of the coil 13 grows in the Z direction between the resin walls 18 of In the winding portion 14 of the coil 13, the growth region is previously defined by the resin wall 18 formed on the substrate 11 before plating growth.

  The winding portion 14 of the coil 13 includes a seed portion 14a which is a part of the spiral pattern 14A, and a plated portion 14b plated and grown on the seed portion 14a, and the plated portion 14b is formed 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 the 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 rectangular cross section (rectangular cross section in FIG. 5) extending long along the normal direction (Z direction) of the substrate 11. That is, the shape of the winding portion 14 of the coil 13 is adjusted by adjusting the shape of the space defined between the resin walls 18, 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 is grown between two adjacent resin walls 18, it grows in contact with the inner side surface of the resin wall 18 which 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 portion 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-adhesive state” refers to a state in which mechanical bonding such as anchor effect and chemical bonding such as covalent bonding do not occur.

  The cross-sectional dimension of the winding portion 14 of the coil 13 is, for example, a height 80 to 260 μm, a width (thickness) 40 to 260 μm, and a ratio (aspect ratio) 1 to 5 of the height to the width (bottom) of the lower end is there. The aspect ratio of the winding portion 14 of the coil 13 may be 2 to 5.

  As shown in FIG. 5, it is preferable that the height h of the winding portion 14 of the coil 13 be 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 part 14 of the coil 13 may stop 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 smaller than the height H of the resin wall 18, the winding portion 14 has a thickness as designed over the height direction. In addition, 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 are in contact with each other, or the thickness of the insulator 40 or the bonding layer 41 described later This is because the pressure resistance of the coil 13 is lowered due to a situation where it can not be secured sufficiently.

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

  Furthermore, as shown in FIG. 5, the upper surface 14 c of the winding portion 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 central portion but gradually descends in a curved shape at the end portion near the resin wall 18 ing. Then, on the upper surface 14c of the winding portion 14 of the coil 13, the height position of the upper surface 14c in contact with the resin wall 18 is the highest height located at the central portion of the upper surface 14c with respect to the relative position of the substrate 11 to the major surface 11a. It is lower than the height position.

  In the embodiment shown in FIG. 5, the thicknesses d1 and d2 of the resin walls 18 are also uniform in 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 in the height direction. That is, the winding portion 14 of the coil 13 has a structure in which there is no or less likely to be a locally thin portion in the height direction (that is, a portion where the pressure resistance is locally reduced). There is. 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 a ratio (aspect ratio) of height to width (bottom side) of the lower end portion 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.

  As shown in FIG. 6, the resin wall 18 is provided separately from the substrate 11, and the lower end surface 18 a is in contact with the major surface 11 a of the substrate 11 to form a bonding surface S. A gap G is formed in the vicinity of the bonding surface S, and the winding portion 14 is separated from the bonding surface S and the lower end portion of the resin wall 18. In other words, the winding portion 14 is separated from the bonding surface S via the gap G existing between the winding portion 14 and the bonding surface S.

  The cross-sectional shape of the air gap G extends along the major surface 11 a of the substrate 11 so as to enter under the winding portion 14 and extends upward along the side surface of the resin wall 18 as shown in FIG. It can be shaped. In this case, the air gap G has a cross-sectional shape including the wedge portion g which gets under the winding portion 14. The cross-sectional shape of the air gap G can be a shape close to a right triangle whose angle corresponding to the joint surface S is a right angle. The gap G can be easily obtained by adjusting the plating conditions at the time of forming the winding portion 14 by plating growth, the composition of the plating solution, and the like, and suppressing the growth in the width direction, for example.

  The space defined by the resin wall 18 is open at the upper end, and the upper end of the resin wall 18 does not wrap around so as to cover the upper side of the winding portion 14. Design freedom is high. That is, an embodiment in which an arbitrary layer is formed on the winding portion 14 and an embodiment in which no layer is formed may 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. 7, an insulator 40 is provided on the winding portion 14 in order to enhance the insulation between the metal magnetic powder contained in the coating resin 21 described later and the winding portion 14. Can. 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 14 c 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. Moreover, 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 by oxidation) can be provided.

  Furthermore, as shown in FIG. 5, it is preferable that the thickness d1 of the resin wall 18 located at the outermost position among the plurality of resin walls 18 be 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 when the coil component 1 is manufactured or used. By disposing the thick resin wall 18 at the outermost position, the portion mainly receives the pressure in this portion. From the viewpoint of rigidity, it is preferable that both resin walls 18 located at both ends be thicker than the thickness of the resin wall 18 located inside.

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

  After plating and growing the coil 13 on the substrate 11, the substrate 11 is entirely covered with the covering resin 21, as shown in FIG. That is, the covering 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 covering resin 21 is made of a metal magnetic powder-containing resin, and is formed on the wafer-like substrate 11 and then cured.

  The metal magnetic powder-containing resin constituting the covering resin 21 is made of a resin in which metal magnetic powder is dispersed. The metallic magnetic powder may be composed of, for example, iron-nickel alloy (permalloy), carbonyl iron, amorphous, amorphous or crystalline FeSiCr-based alloy, sendust, and the like. The resin used for the metal magnetic powder-containing resin is, for example, a thermosetting epoxy resin. Content of the metal magnetic powder contained in metal magnetic powder containing resin is 90-99 wt% as an example.

  Furthermore, by dicing into chips, the main body 10 shown in FIG. 9 is obtained. After forming the chip, the edge may be chamfered by barrel polishing or the like, if necessary.

  Finally, the external terminal electrodes 30A and 30B are provided on the end surface (the end surface facing in the Y direction) where the end portion pattern 15A of the main body portion 10 is exposed so as to electrically connect to the end portion pattern 15A. Part 1 is completed. The external terminal electrodes 30A and 30B are electrodes for connecting to the circuit of the substrate on which the coil component is mounted, and can 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 metal plating the resin electrode material. For metal plating of the external terminal electrodes 30A, 30B, Cr, Cu, Ni, Sn, Au, solder or the like can be used.

  According to the coil component 1 described above, since the winding portion 14 is separated from the joint surface S between the lower end portion of the resin wall 18 and the main surface 11 a of the substrate 11, winding adjacent to each other via the resin wall 18 The portions 14 are far apart in the vicinity of the bonding surface S. This is because the distance between adjacent winding portions 14 (that is, the creeping distance) is not separated in the vicinity of the bonding surface S when considering a mode in which short circuiting is performed via the bonding surface S (i.e., creeping distance) That is, it means that it is extended compared with the case where the air gap G does not exist. Thereby, the short circuit via the bonding surface S is suppressed, and as a result, the withstand voltage improvement between the winding portions 14 is realized.

  Moreover, since the winding portion 14 is separated from the bonding surface S, it is less likely that plating will intrude between the bonding surfaces S and the withstand voltage decreases.

  In particular, when the air gap G has a cross-sectional shape including the wedge portion g which enters under the winding portion 14, the distance between the adjacent winding portions 14 is further extended, so that the withstand voltage can be further improved. .

  Further, according to the coil component 1, the height position at which the upper surface 14 c of the winding portion 14 of the coil 13 contacts the resin wall 18 is lower than the highest height position on the upper surface 14 c. Therefore, the creeping distance from the winding portion 14 to the winding portion 14 adjacent to the winding portion 14 via the resin wall 18 is extended, and the withstand voltage is improved between the winding portions 14 adjacent to each other.

  Furthermore, according to the coil component 1, since the winding portion 14 of the coil 13 is interposed between the plurality of resin walls 18 in a non-adhesive state, the winding portion 14 of the coil 13 and the resin wall 18 are displaced relative to each other It is possible. Therefore, there is a change in the ambient temperature such as when the use environment of the coil component 1 becomes high, and a stress occurs due to the difference in the thermal expansion coefficient between the winding portion 14 of the coil 13 and the resin wall 18 Even in this case, the stress is relaxed by relative movement of the winding portion 14 of the coil 13 and the resin wall 18.

  Further, according to the method of manufacturing 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 wound portions 14 of the coil 13, and the resin wall 18 stabilizes the dimensional accuracy of the resin between the wound portions 14 of the coil 13.

  DESCRIPTION OF SYMBOLS 1 ... Coil part, 11 ... Board | substrate, 13 ... Coil, 14 ... Winding part, 14a ... Seed part, 14b ... Plating part, 14c ... Upper surface, 17 ... Resin body, 18 ... Resin wall, 18a ... Lower end surface, 21 ... Coating resin, 30A, 30B: external terminal electrode, 40: insulator, G: air gap, g: wedge portion, S: bonding surface.

Claims (10)

A substrate,
A coil provided by plating growth on the main surface of the substrate;
A resin body having a plurality of resin walls provided on the main surface of the substrate and in which the winding portion of the coil extends therebetween;
And a covering 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 coil component, wherein the winding portion is separated from a joint surface where the lower end of the resin wall is joined to the main surface of the substrate.   The coil component according to claim 1, wherein an air gap exists between the winding portion and the joint surface, and the winding portion is separated from the joint surface via the air gap.   The coil component according to claim 2, wherein the air gap has a cross-sectional shape including a wedge portion which gets under the winding portion. The coil component according to claim 1, wherein a cross-sectional shape of a winding portion of the coil is a square shape. The coil component according to any one of claims 1 to 4 , wherein a cross-sectional shape of a resin wall of the resin body is a square shape. The section of the resin wall of the resin body is greater than 1 the ratio of the height to the length of the base, the resin wall is elongated along a normal direction of a principal face of the substrate, according to claim 5 Coil parts.   7. The coil according to claim 6, wherein a cross section of the winding portion has a height to bottom length ratio of greater than 1, and a cross section of the winding portion extends in a direction normal to the main surface of the substrate. Coil parts 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. Windings of pre Symbol coils are not bonded to the resin wall of the resin body, a coil component according to any one of claims 1-8.   The resin wall according to any one of claims 1 to 9, wherein among the plurality of resin walls arranged on the main surface of the substrate, the thickness of the resin wall located at the outermost side is thicker than the thickness of the resin wall located inside. Coil parts.

Images