JP2006278912A - Coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reliable coil component by solving the problem that, during manufacture, an air bubble is trapped in the resin material at a corner of a core, and the air bubble cannot be removed, which degrades the reliability of the coil component. <P>SOLUTION: The boundary surface between a protruded portion and a base is composed of a curved surface that passes through the center of a planar coil 34, and whose curvature radius R is 30 μm or above. The boundary surface may be a flat surface including a line segment of 30 μm or above inclined with respect to the principal plane of the base. In this case, a boundary surface BS1 exists between the base 111 and first and second outer legs 112, respectively, and an air bubble is less prone to be trapped in the bonding material 40 positioned in proximity to each boundary surface during manufacture. More specific description will be given. Fluctuation is reduced in the distance between a coil 34 or a coil peripheral material 33 and the inner wall of a core 11, and an air bubble is less prone to be trapped in the bonding material 40 during manufacture. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coil component.

  Miniaturization of electronic components constituting electronic devices is expected. Coil parts are used in power supply circuits and the like, but conventionally, coil-type inductors in which a ferrite core is wound have been used as coil parts. However, there is a limit to the downsizing of the winding type inductor, and a planar coil is being researched instead of the winding.

For example, a thin-film power inductor manufacturing method (Patent Document 1) in which a conductor is spirally screen-printed on a ceramic substrate to form a planar coil, and a ferrite green sheet is placed thereon and fired (Patent Document 1), insulation There is known a method for manufacturing a planar inductor (Patent Document 2) in which a coil-shaped groove is formed in a magnetic substrate, a coil-shaped conductor is formed in the groove, and the coil is covered with a magnetic substrate. There is also known a coil component in which a planar coil is sandwiched between a lower magnetic ferrite sintered substrate and an upper magnetic ferrite substrate, and a resin material is filled between the planar coil and each core. (For example, refer to Patent Documents 3 and 4 below).
JP-A-6-260361 JP-A-5-315177 JP 2004-349468 A JP-A-8-153263

  However, in conventional coil parts, bubbles are entrained in the resin material at the corners of the core at the time of manufacture, and in particular, when the viscosity of the resin material is high, the bubbles cannot be removed. There was a problem that decreased.

  This invention is made | formed in view of such a subject, and it aims at providing a more reliable coil component.

  In order to solve the above-described problem, a coil component according to a first invention includes a core having a protruding portion erected from a flat base, a planar coil facing the core, and a resin interposed between the core and the planar coil. In the coil component comprising the material, the projecting portion is located inside the planar coil, and the boundary surface between the base portion and the projecting portion is (1) in a plane passing through the center of the planar coil and along the thickness direction of the base portion. A curved surface having a radius of curvature of 30 μm or more at the minimum, or (2) the minimum length of the line segment that is inclined with respect to the main plane of the base in the plane and that forms an intersection line between the boundary plane and the plane The value is a plane of 30 μm or more.

  In this coil component, when a current is passed through a planar coil, a magnetic flux (flux of magnetic field lines) passing through the center of the coil is generated according to the "Ampere's Law (Right-Thread Law)", and this magnetic flux is located inside the planar coil. A magnetic circuit is formed through the protruding portion. There is a boundary surface between the base portion and the protruding portion, and bubbles are less likely to be mixed in the adhesive material located in the vicinity of the boundary surface during manufacturing. That is, since the variation in the distance between the coil or the coil peripheral material and the inner wall of the core is reduced, bubbles are less likely to be mixed in the adhesive material during manufacturing.

  When the curved surface is an elliptical cylindrical surface having two focal points, or when the curved surface is a curved surface made up of an arc having a plurality of curvature radii, the minimum curvature radius (short radius in the case of an ellipse) is 30 μm or more. Suppose that there is.

  In addition, when the boundary surface is a plane having a line segment length of 30 μm or more, the line segment constituting the plane is not a line segment expressed mathematically strictly, but may include a slight curve. Good. When this line segment is called a “pseudo line segment”, the maximum separation distance of the pseudo line segment with respect to the straight line connecting the start point and the end point of the pseudo line segment is 5% or less of the length between the start point and the end point. I will do it.

  Incidentally, when the boundary surface is formed by using a laser processing method or a blade processing method using a grindstone having a particle diameter of about 10 μm, the radius of curvature becomes 15 μm or less.

  The coil component according to the second invention includes a core having first and second protrusions erected from a flat base, a planar coil facing the core, a resin material interposed between the core and the planar coil, The planar coil is located between the first and second projecting portions, and each of the boundary surfaces between the base and the first and second projecting portions passes through the center of the planar coil and (1) A curved surface having a radius of curvature of 30 μm or more in the plane along the thickness direction of the base, or (2) in the plane, inclined with respect to the main plane of the base, and the line of intersection between the boundary surface and the plane The minimum length of the line segment to be formed is a plane of 30 μm or more.

  In this coil component, when a current is passed through the planar coil, a magnetic flux passing through the center of the coil is generated according to Ampere's law, and this magnetic flux passes through the first and second protrusions located outside the planar coil. Configure. There are boundary surfaces between the base and the first and second protrusions, respectively, and in the adhesive material located in the vicinity of each boundary surface, it is difficult for air bubbles to be mixed during manufacturing, as in the first invention. Become.

  A coil component according to a third aspect of the present invention includes a first core having a first protrusion standing from a flat plate-like first base, and second and third protrusions standing from a flat plate-like second base. A coil component comprising: a second core; a planar coil positioned between the first and second cores; and a resin material interposed between the first and second cores and the planar coil. Is located inside the planar coil, the planar coil is located between the second and third protrusions, and the boundary surface between the first base and the first protrusion is (1) passing through the center of the planar coil and A curved surface having a minimum radius of curvature of 30 μm or more in the plane along the thickness direction of the first base, or (2) in the plane, inclined with respect to the main plane of the first base, the boundary surface and the plane The minimum value of the length of the line segment constituting the line of intersection with the plane is 30 μm or more. To do.

  A coil component according to a fourth aspect of the present invention includes a first core having a first protrusion standing from a flat plate-like first base, and second and third protrusions standing from a flat plate-like second base. In a coil component comprising a second core, a planar coil positioned between the first and second cores, and a resin material interposed between the first and second cores and the planar coil, the first protrusion is It is located inside the planar coil, the planar coil is located between the second and third protrusions, and each of the boundary surfaces between the second base and the second and third protrusions is (1) the center of the planar coil Or a curved surface having a radius of curvature of 30 μm or more in the plane along the thickness direction of the second base, or (2) the boundary surface is inclined with respect to the main plane of the second base in the plane. And the minimum value of the length of the line segment constituting the line of intersection with the plane is a plane of 30 μm or more It is characterized by that.

  In the coil component according to the third and fourth inventions, when a current is passed through the planar coil, a magnetic flux passing through the center of the coil is generated in accordance with Ampere's law, and this magnetic flux is in the first protruding portion located inside the planar coil. And a magnetic circuit is formed through the second and third protrusions located outside the planar coil. A boundary surface exists between the base and the first protrusion, or between the base and the second and third protrusions, and the first adhesive material located in the vicinity of each boundary surface includes the first As with the invention, bubbles are less likely to be mixed during manufacturing.

  As described above, when mixing of bubbles into the resin material is suppressed, the planar coil is stably bonded to the core via the adhesive material, and magnetic saturation is suppressed due to the presence of the boundary surface. Therefore, the reliability will be improved.

In addition, it is preferable that the resin material application area of the base main surface perpendicular | vertical to a protrusion part is 20 mm < ² > or less. In this case, the coil component can be made small, and the radius of curvature of the boundary surface at this time is preferably 300 μm or less so that the core does not contact the coil.

  According to the coil component of the present invention, a highly reliable coil component can be provided.

Hereinafter, the coil component according to the embodiment will be described. In addition, the same code | symbol is attached | subjected to the same part and the overlapping description is abbreviate | omitted.
(First embodiment)

  FIG. 1 is a perspective view of a coil component 1 in the present embodiment.

  The coil component 1 is a surface mount type coil component. The coil component 1 includes a flat core structure 10 and external terminals 20 that are electrically connected to other substrates. The core structure 10 mainly includes a flat lower ferrite core 12 (first core) and a flat upper ferrite core 11 (second core). The upper ferrite core 11 and the lower ferrite core 12 is combined to form a flat plate shape as a whole.

  An XYZ orthogonal coordinate system is set as shown. The cross-sectional shape of the coil component 1 in the XY plane is a quadrangle with a side of several millimeters. When the thickness direction of the coil component 1 is the Z direction, the external terminal 20 is provided on a plane parallel to the XZ plane.

  FIG. 2 is an exploded perspective view of the coil structure 10.

  The upper ferrite core 11 has a rectangular flat plate portion (base portion) 111 and a pair of outer leg portions (protrusion portions) 112 erected vertically (−Z direction) with respect to the flat plate portion 111. Yes. One outer leg portion 112 extends from one side of the flat plate portion 111 and the other outer leg portion 112 extends from the side parallel to the one side in the same direction (Y direction). Therefore, when the upper ferrite core 11 is arranged on the lower ferrite core 12 so that the longitudinal direction of the outer leg portion 112 is along two opposite sides of the lower ferrite core 12, the flat plate portion 111 and the lower ferrite core 12 of the upper ferrite core 11 are disposed. A gap is formed between the two.

  The lower ferrite core 12 has a rectangular flat plate portion (base portion) 121 and a middle leg portion (protrusion portion) 122 that protrudes from the central portion of the flat plate portion 121. The middle leg portion 122 is a convex portion having a substantially prismatic shape, and has a cylindrical surface curved inward along an axis parallel to each side of the flat plate portion 121.

  When the tip surface of the leg portion 112 of the upper ferrite core 11 is abutted on the flat plate portion 121 of the lower ferrite core 12 to constitute the core structure 10, an outer shell portion that is substantially a closed magnetic path is formed. At this time, the middle leg portion 122 is disposed inside the outer shell portion.

  The detailed structure of the upper ferrite core 11 and the lower ferrite core 12 will be described as appropriate hereinafter.

  FIG. 3 is a perspective view of the coil component with the external terminal 20 removed from the state of FIG.

  A coil substrate 30 is housed in a gap portion between the upper ferrite core 11 and the lower ferrite core 12 constituting the core structure 10.

  The coil substrate 30 is covered with a protective resin layer 33. An adhesive resin material 40 is provided around the protective resin layer 33. Therefore, the protective resin layer 33 and the adhesive resin material 40 are interposed between the coil substrate 30 and the core structure 10. The adhesive resin material 40 fixes the coil substrate 30 covered with the protective resin layer 33 to the core structure 10. The protective resin layer 33 easily enters between the windings of the planar coil, and the adhesive strength between the upper ferrite core 11 and the lower ferrite core 12, the protective resin layer 33, the resin material 40, and the coil is ensured.

  One end surface of the coil substrate 30 constitutes one end surface of the core structure 10 and is exposed to the outside. At the one end surface, the side surfaces of the insulating plate 31, the lead-out end electrode 32, and the protective resin layer 33 are exposed. The insulating plate 31 is a substrate that becomes a core portion constituting the coil substrate 30. The lead-out end electrode 32 is electrically connected to a coil, which will be described later, and is a portion that is also electrically connected to the external terminal 20 shown in FIG.

  FIG. 4 is a plan view of the coil substrate 30.

  A circular opening 35 is formed in the central portion of the coil substrate 30. The planar coil 34 formed of a conductive material is disposed so as to surround the circular opening 35. The planar coils 34 are formed on both surfaces of the coil substrate 30 and are electrically connected to the lead-out end electrodes 32, respectively. Each coil 34 spirally extends from the vicinity of the circular opening 35 toward the outside.

  When viewed from the direction facing the coil exposed surface, the planar coil 34 on one side forms a left-handed spiral along the direction toward the outer side, and the planar coil 34 on the other side also looks from the direction facing the coil exposed surface. As seen, when a left-handed spiral is formed along the outward direction, these central portions are electrically connected and overlapped, and when current flows in one direction, the rotational direction in which the current flows is the same Is set to That is, the magnetic fluxes generated by the two planar coils 34 are superimposed and strengthened.

  The lead-out end electrode 32 connected to the planar coil 34 formed on one surface of the coil substrate 30 and the lead-out end electrode 32 connected to the planar coil 34 formed on the other surface are respectively coil substrates. It is provided on 30 opposite sides. The planar coils 34 provided on both surfaces of the coil substrate 30 are electrically connected to each other by front and back contact portions 36 formed at the peripheral edge of the circular opening 35. The front and back contact portions 36 penetrate the insulating plate 31 in the thickness direction.

  Therefore, when a voltage is applied between the lead-out end electrode 32 provided on one side of the coil substrate 30 and the lead-out end electrode 32 provided on the other side, it is formed on one surface of the coil substrate 30. A current flows from the coil 34 that is formed to the coil 34 that is formed on the other surface.

  The middle leg portion 122 of the lower ferrite core 12 is inserted into the circular opening 35 of the coil substrate 30.

  FIG. 5 is a cross-sectional view (vertical cross-sectional view) of the VV arrow of the coil component 1 shown in FIG.

  The coil base material 100 including the coil substrate 30 and the protective resin layer 33 is disposed between the upper ferrite core 11 and the lower ferrite core 12. The middle leg portion 122 of the lower ferrite core 12 is inserted into a circular opening 35 (see FIG. 4) of the coil substrate 30. The outer leg portion 112 of the upper ferrite core 11 and the middle leg portion 122 of the lower ferrite core 12 are formed to have substantially the same length.

  Therefore, when the upper ferrite core 11 and the lower ferrite core 12 are arranged at a predetermined interval, a gap is generated between the tip of the middle leg portion 122 and the upper ferrite core 11, and the minute gap 41 can be formed. Similarly, a gap is generated between the tip of the outer leg portion 112 and the lower ferrite core 12, and the minute gap 42 can be formed.

  In the case of the present embodiment, the surface (main surface) on which the middle leg portion 122 of the lower ferrite core 12 is formed and the surface (main surface) on which the outer leg portion 112 of the upper ferrite core 11 is formed, respectively. The resin material 40 for adhesion | attachment is applied along. The coil substrate 30 is fixed via a resin material 40 so as to be sandwiched between the upper and lower cores 12 and 11. The minute gaps 41 and 42 are filled with a resin material 40 for bonding.

  The magnetic flux generated by the coil current passes through the upper ferrite core 11 and the lower ferrite core 12, but the minute gaps 41 and 42 interposed in the magnetic circuit suppress magnetic saturation. Since the core structure 10 has an ultra-compact shape with a side of several millimeters or less, the dimensions of the minute gaps 41 and 42 (the distance between the tip of the middle leg 122 and the upper ferrite core 11, the outer leg The distance between the tip of the portion 112 and the lower ferrite core 12) is preferably set to 0.1 to 100 μm, more preferably 0.1 to 50 μm.

  A Cu treatment layer 34 a is uniformly formed on the surfaces of the coil 34 and the front and back contact portions 36. Therefore, the protective resin layer 33 disposed around the coil substrate 30 uniformly enters between the windings of the coil 34. As a result, it is difficult to form a minute cavity between the coil 34 and the protective resin layer 33, and the adhesion between the coil 34 and the protective resin layer 33 is further improved.

  Subsequently, a method for manufacturing the coil substrate 30 will be described with reference to FIGS.

6 and 7 are views for explaining a method of manufacturing the coil substrate 30 and illustrate a cross section of a portion corresponding to a part of the coil substrate 30. FIG. First, the insulating plate 31 is prepared (see FIG. 6A). This insulating plate 31 has a thickness of 60 μm, and glass cloth is impregnated with cyanate resin (BT (bismaleimide / triazine) resin: registered trademark), and a circular opening 35 is already formed. (Not shown in FIG. 6).
Subsequently, the base layer 60 is simultaneously formed on the front and back surfaces of the insulating plate 31 by electroless plating (see FIG. 6B).

  Next, a photoresist layer 61 (resist layer) is simultaneously electrodeposited on each of the underlying layers 61 formed simultaneously on the front and back surfaces of the insulating plate 31 (see FIG. 6C). In the photoresist layer 61 formed on the front and back surfaces, exposure is performed on each side of the front and back surfaces by photolithography along the pattern for forming the coil conductor 34 (see FIG. 4). Development is performed to form a removal portion 611 (see FIG. 6D).

  Using the patterned photoresist layer 61 as a plating mask, a portion corresponding to the removed portion 611 in FIG. 6D is selectively subjected to electrolytic plating to simultaneously coat both the front and back surfaces of the coil conductor plating layer 62 ( A first electroplating layer is formed (see FIG. 7A). FIG. 8 is a configuration diagram of a film forming apparatus 8 used when forming an electrolytic plating film.

The film forming apparatus 8 has a liquid tank 81, and a plating solution is placed in the liquid tank 81. A plating jig 82 for holding a wafer 83 on which an electrolytic plating film is formed is disposed in the liquid tank 81. The plating jig 82 is provided with a jig shielding plate 821 to shield the outer peripheral portion of the wafer 83. A pair of anodes 84 is provided so as to sandwich the plating jig 82. An outer shielding plate 85 and a stirring grid 86 are provided between the plating jig 82 and the pair of anodes 84, respectively. Since a predetermined voltage is applied between the plating jig 82 and the pair of anodes 84, it is possible to simultaneously perform plating on both surfaces of the wafer 83 attached to the plating jig 82.
In this way, for example, a Cu conductor pattern (conductor line) having a height of 20 μm, a width of 70 μm, and a gap of 30 μm can be formed. The “height” and “width” are the height and width of the Cu conductor pattern, and the gap here is the distance between adjacent Cu conductor patterns.

After this coil conductor plating layer 62 is formed, the photoresist layer 61 as a plating mask is peeled and removed simultaneously on both the front and back surfaces (see FIG. 7B).

  From the state shown in FIG. 7B, the base layer 60 other than the portion where the coil conductor plating layer 62 is formed is removed by etching, and the base portion 60a is removed from the coil conductor plating layer 62, the insulating plate 31, and the like. (See FIG. 7C).

  After that, without the selective plating mask, the second electrolytic plating is performed simultaneously on both sides using the apparatus shown in FIG. 8, and the coil conductor plating layer 62 is further grown and formed by electrodeposition (see FIG. 7D). For example, a Cu conductor pattern having a height of 80 to 100 μm, a width of 80 to 85 μm, and a gap of 15 μm is formed on both sides simultaneously.

  Thereby, a sufficiently thick conductor portion as the planar coil 34 is obtained. The planar coil 34 can be grown and formed at a high density until the gap G between adjacent coil conductors is 15 μm or less. This is because the plating layer is formed in proportion to the amount of electricity in the height direction, but the rate at which the plating layer is formed becomes slower as the gap becomes narrower in the width (gap G) direction. by.

  Thus, the coil substrate 30 has the planar coil 34 in which the electroplating layer 62 is grown at a high density until the gap G between the adjacent planar coils 34 becomes 15 μm or less. Moreover, since the aspect ratio of the coil conductor (height / width of the planar coil 34) can be set as high as about 0.2 to 5, the direct current resistance can be reduced to about 0.01 to 10 ohms. .

  After the formation of the coil conductor plating layer 62 is completed, after the planar coil 34 has been formed on both surfaces of the insulating plate 31, the top surface of the planar coil 34 is polished to remove the excess portion 34K, and the planar coil 34 Make the in-plane height uniform. The height uniformity is performed so that the maximum deviation from the average value is 10% or less.

  Next, the surface Cu on which the Cu conductor pattern is formed is treated to form a Cu treatment layer 34a. The Cu treatment layer 34a is formed by a roughening treatment in which irregularities (for example, 5 μm to 7 μm) are provided on the copper surface, or an oxidation treatment in which an oxide film is provided on the copper surface. Moreover, you may use a roughening process and an oxidation process together. The adhesive strength with the resin 33 is improved by the Cu treatment layer 34a. In addition, the resin 33 easily enters between the lines of the Cu conductor.

  Next, the protective resin layer 33 (solder resist) is printed on both surfaces of the insulating plate 31, and the planar resin 34 is covered and protected by the protective resin layer 33 to complete the coil base material 100 including the coil substrate 30. . Actually, in order to produce a plurality of coils at a time, a wafer (coil substrate assembly) in which coil conductors of a spiral pattern are aligned is produced. Further, Cr and Cu are continuously formed on the solder resist by a mask sputtering method, and an electrode is taken out from the center of the spiral.

  Each coil substrate is sandwiched between upper and lower ferrite substrates and bonded using an epoxy adhesive while being pressurized in a 150 ° C. atmosphere. The bonded substrate is ground flat to a thickness of 0.77 mm with a high-precision slicer, and then chipped with a dicer to produce each element.

  Thereafter, in order to form an external terminal electrode to be a user terminal for circuit connection, after barrel polishing, the terminal surface Cu (leading end electrode portion) is cleaned using both wet processing and dry processing, Cr and Cu are continuously formed by mask sputtering. By subjecting this to barrel plating of Cu, Ni, and Sn, for example, a coil component 1 that is a surface-mounted coil element having a product size of 3 mm long × 2.6 mm wide × 0.8 mm high can be produced.

  Next, the shapes of the upper ferrite core 11 and the lower ferrite core 12 will be described in detail.

  As shown in FIG. 5, the upper ferrite core 11 having a bridge shape has a pair of outer legs 112 arranged to face each other, and each outer leg 112 extends from the base 111 to its main surface 111a. On the other hand, it stands upright in the vertical direction (−Z direction) and extends linearly along the outer edge of the upper ferrite core 11. Further, the middle leg portion 122 of the lower ferrite core 12 is erected in the vertical direction (Z direction) from the central portion of the base portion 121 with respect to the main surface (XY plane) 121a. The base of the outer leg part 112 and the middle leg part 122 is subjected to R processing or C processing.

  FIG. 9 is an enlarged view of the region A1 shown in FIG.

  The planar coil 34 is located between the first and second outer legs 112.

  The boundary surface BS1 between the base 111 and the first outer leg 112 is (1) a plane that passes through the center of the planar coil 34 and extends in the thickness direction (Z direction) of the base 111 (paper surface in FIG. 5: XZ plane). ) Is a curved surface having a minimum radius of curvature R of 30 μm or more.

  The structure of the boundary surface between the base portion 111 and the other second outer leg portion 112 is the same as the boundary surface BS1, and these boundary surfaces are perpendicular to the paper surface (XZ plane) of FIG. It is in a mirror image relation to a plane (YZ plane) perpendicular to (121a).

  In this coil component, when a current is passed through the planar coil 34, a magnetic flux passing through the center of the coil is generated according to Ampere's law, and this magnetic flux passes through the first and second outer legs 112 located outside the planar coil. A magnetic circuit is formed through. There are boundary surfaces (BS1) between the base portion 111 and the first and second outer leg portions 112, respectively, and bubbles are less likely to be mixed in the adhesive material 40 located near each boundary surface during manufacturing. . That is, since the variation in the distance between the coil 34 or the coil peripheral material 33 and the inner wall of the core 11 is reduced, bubbles are less likely to be mixed in the adhesive material 40 during manufacturing.

  In addition, when the curved surface is an elliptical cylindrical surface having two focal points, or when the curved surface is a curved surface formed by an aggregate of arcs having a plurality of curvature radii, the minimum curvature radius (short radius in the case of an ellipse) R is 30 μm or more. Suppose that The inner resin 33 is similarly R-processed or C-processed.

  FIG. 10 is an enlarged view of a modified example of the region A1 shown in FIG.

  The boundary surface BS2 between the base portion 111 of the upper ferrite core 11 and the first outer leg portion 112 is (2) inclined with respect to the main plane 111a of the base portion 111 in the plane (the paper surface of FIG. 5). The minimum value of the length C of the line segment constituting the intersection line between BS2 and the plane (the paper surface of FIG. 5) is a plane of 30 μm or more.

  The structure of the boundary surface between the base portion 111 and the other second outer leg portion 112 in the case of this modification is the same as the boundary surface BS2, and these boundary surfaces are also perpendicular to the paper surface (XZ plane) in FIG. Therefore, it is in a mirror image relationship with a plane (YZ plane) perpendicular to the main surface 111a (121a).

  In this coil component, when a current is passed through the planar coil 34, a magnetic flux passing through the center of the coil 34 is generated according to Ampere's law, and this magnetic flux is the first and second outer legs 112 positioned outside the planar coil 34. A magnetic circuit is formed through the inside. There are boundary surfaces (BS2) between the base portion 111 and the first and second outer leg portions 112, respectively, and bubbles are less likely to be mixed in the adhesive material 40 located in the vicinity of each boundary surface during manufacturing. . That is, since the variation in the distance between the coil 34 or the coil peripheral material 33 and the inner wall of the core 11 is reduced, bubbles are less likely to be mixed in the adhesive material 40 during manufacturing.

  Further, when the boundary surface BS4 is a plane having a line segment length C = 30 μm or more, the line segment constituting the plane is not a line segment expressed mathematically strictly but includes a slight curve. There may be. When this line segment is called a “pseudo line segment”, the maximum separation distance of the pseudo line segment with respect to the straight line connecting the start point and the end point of the pseudo line segment is 5% or less of the length between the start point and the end point. I will do it.

  FIG. 11 is an enlarged view of the region A2 shown in FIG.

  The middle leg portion 122 is located inside the planar coil 34. The boundary surface BS3 between the base 121 and the middle leg 122 has (1) a radius of curvature R in a plane passing through the center of the planar coil 34 and along the thickness direction of the base (paper surface in FIG. 5) of 30 μm or more. It is a curved surface.

  The structure of the boundary surface between the base portion 111 and the middle leg portion 122 on the left side in FIG. 5 is the same as the boundary surface BS3, and these boundary surfaces are perpendicular to the paper surface (XZ plane) in FIG. It is in a mirror image relation to a plane (YZ plane) perpendicular to 111a (121a). Further, the structure of the boundary surface between the base portion 111 and the middle leg portion 122 has the same structure even at a position in a mirror image relation with respect to the paper surface of FIG.

  In this coil component, when a current is passed through the planar coil 34, a magnetic flux passing through the center of the coil 34 is generated according to Ampere's law, and this magnetic flux passes through the middle leg portion 122 located inside the planar coil 34. Configure the circuit. A boundary surface BS3 exists between the base 121 and the middle leg portion 122, and bubbles are less likely to be mixed in the adhesive material 40 located in the vicinity of the boundary surface BS3 during manufacturing. That is, since the fluctuation of the distance between the coil 34 or the coil peripheral material 33 and the inner wall of the core 12 becomes small, bubbles are hardly mixed in the adhesive material 40 during manufacturing.

  In addition, when the curved surface is an elliptical cylindrical surface having two focal points, or when the curved surface is a curved surface formed by an aggregate of arcs having a plurality of curvature radii, the minimum curvature radius (short radius in the case of an ellipse) R is 30 μm or more. Suppose that

  FIG. 12 is an enlarged view of a modified example of the region A2 shown in FIG.

  The boundary surface BS4 between the base portion 121 and the middle leg portion 122 in the case of this modification is inclined with respect to the main plane 121a of the base portion 121 in the above-described plane (paper surface of FIG. 5). This is a plane in which the minimum value of the length C of the line segment constituting the intersecting line with the plane is 30 μm or more.

  The structure of the boundary surface between the base portion 111 and the other middle leg portion 122 in the case of the modification is the same as the boundary surface BS4, and these boundary surfaces are also perpendicular to the paper surface (XZ plane) in FIG. It is in a mirror image relationship with a plane (YZ plane) perpendicular to the main surface 111a (121a). Further, the structure of the boundary surface between the base portion 111 and the middle leg portion 122 has the same structure even at a position in a mirror image relation with respect to the paper surface of FIG.

  In this coil component, when a current is passed through the planar coil 34, a magnetic flux passing through the center of the coil 34 is generated according to Ampere's law, and this magnetic flux passes through the middle leg portion 122 located inside the planar coil 34. Configure the circuit. The boundary surface BS4 exists between the base 121 and the middle leg portion 122, and bubbles are less likely to be mixed in the adhesive material 40 located in the vicinity of the boundary surface BS4 during manufacturing. That is, since the fluctuation of the distance between the coil 34 or the coil peripheral material 33 and the inner wall of the core 12 becomes small, bubbles are hardly mixed in the adhesive material 40 during manufacturing.

  Further, when the boundary surface BS4 is a plane having a line segment length C = 30 μm or more, the line segment constituting the plane is not a line segment expressed mathematically strictly but includes a slight curve. There may be. When this line segment is called a “pseudo line segment”, the maximum separation distance of the pseudo line segment with respect to the straight line connecting the start point and the end point of the pseudo line segment is 5% or less of the length between the start point and the end point. I will do it.

  Incidentally, when the boundary surface is formed using a laser processing method or a cutting method using a blade made of a grindstone having a particle size of about 10 μm, the radius of curvature R becomes 15 μm or less. In this example, cutting is performed using a blade slicer made of a grindstone with a particle size of 20 μm and a metal bond, and R processing with a radius of curvature R of 30 μm or more is performed. Also, by changing the blade and dressing conditions, R processing with a curvature radius R of 30 μm or more, specifically, R processing with a curvature radius R of 80 μm, or C processing with a line segment length C of 30 μm or more is performed. You can also.

  When a current is passed through the planar coil 34 shown in FIGS. 9 to 12, a magnetic flux passing through the center of the coil 34 is generated according to Ampere's law, and this magnetic flux is the middle leg portion 122 located inside the planar coil 34. A magnetic circuit is formed through the outer leg 112 located inside and outside the planar coil 34. Further, boundary surfaces BS1 (BS2, BS3, BS4) exist between the base portion 121 and the middle leg portion 122, or between the base portion 111 and the outer leg portion 112, and are located in the vicinity of each boundary surface. Bubbles are less likely to enter the adhesive material 40 during manufacturing. In this way, when the mixing of bubbles into the resin material 40 is suppressed, the planar coil 34 is stably bonded to the cores 11 and 12 via the adhesive material 40, and the boundary surface BS1 (BS2, BS2 Since the magnetic saturation is suppressed by the presence of BS3, BS4), the allowable current is increased, the mechanical strength is increased, and the reliability is improved.

In addition, the resin material application area of the base main surface 121a perpendicular to the middle leg part 122 or the resin material application area of the base main surface 111a perpendicular to the outer leg part 112 is 20 mm ² or less from the viewpoint of miniaturization. Is preferred. Although the coil component can be reduced in size, the radius of curvature R of the boundary surfaces BS1 and BS3 at this time is preferably 300 μm or less so that the cores 11 and 12 do not contact the coil. Further, the length C of the line segments of the boundary surfaces BS2 and BS4 at this time is preferably set to 300 μm or less so that the cores 11 and 12 do not contact the coil 34.

  A distance D between the core 11 and the outer peripheral resin 33 of the coil substrate 30 can be 30 μm or less, and a corner portion of the outer peripheral resin 33 is chamfered such as R processing or C processing as necessary. ing. In addition, when the heat | fever more than a softening point is applied to resin 33, a corner | angular part will become round.

  FIG. 13 is a longitudinal section of the conductor wire perpendicular to the direction in which the conductor wire constituting the planar coil 34 extends.

The top surface 34t of the conductor wire constituting the planar coil 34 is flattened by polishing, and the ratio r (= W ₁ / W ₂₎ between the X-direction width W ₁ in the flat portion and the maximum value W ₂ of the conductor wire. ) Is 0.3 or more and less than 1.0 in a plane. That is, after the electrolytic plating is performed until the gap G between the conductor wires is minimized, in this case, there is a large variation in the in-plane height of the conductor wires, but this is a plane parallel to the XY plane (polishing surface). ) To suppress the “height” and “in-plane variation in height” while maximizing the longitudinal sectional area of the conductor wire, that is, reducing the resistance value. Can do.

  That is, in the conventional conductor wire, the height was 80 to 100 μm, the width was 80 to 85 μm, and the gap was 15 μm. In this embodiment, by polishing the top surface 34 t of the conductor wire, the height is 100 to 150 μm and the width is After forming a conductor of 85 μm or more and a gap G of 10 μm or less as the first stage, planarization polishing is performed in the second stage, thereby maximizing the cross-sectional area and “in-plane variation in height” Can be suppressed.

  That is, the coil substrate includes a planar coil 34 made of a conductor wire plated and grown on the substrate, and a gap G between adjacent conductor wires in a cross section perpendicular to the extending direction of the conductor wire is 10 μm or less. In addition, the top surface 34t of the conductor wire is flattened.

Cutting or polishing of the top surface 34t of the conductor wire can be performed with a high-precision lapping apparatus until the entire thickness of the coil substrate 30 becomes 0.22 mm (220 μm) or less. Since the insulating substrate thickness of the BT resin is 60 μm, it can be polished until the height of the upper and lower conductor lines is 80 μm or less. The ratio r (= W ₁ / W ₂ ) could be 0.8, for example.

  When the coil component 1 having a size of 3 mm in length, 2.6 mm in width, and 0.8 mm in height was manufactured with these values, the DC resistance value of the coil decreased from the conventional 300 mΩ to 260 mΩ. The maximum thickness of the upper ferrite core 11 is 0.77 mm, which is obtained by machining a plate-like ferrite core into a concave shape using a diamond wheel grindstone. The maximum thickness is also 0.77 mm, and this is also obtained by machining a plate-like ferrite core into a central convex shape using a diamond wheel grindstone.

  An epoxy adhesive is interposed between the ferrite cores 11 and 12 as the resin material 40. This is because the coil substrate 30 is pressed while pressing the upper and lower ferrite cores 11 and 12 in an atmosphere of 150 ° C. It was used when bonding.

  Although the planar coil 34 is formed by plating growth on an insulating substrate, it can also be plated and grown on a ferrite core substrate or other substrate to flatten the top surface of the conductor wire.

  FIG. 14 is a table showing the radius of curvature R, the number of bubbles in the resin material 40, and the allowable current (A). The radius of curvature R is the average value of the four radiuses of curvature measured when four cross-sections on the XZ plane are set, the number of bubbles is the result of visual observation, and the allowable current is 20% higher than the initial value of the coil inductance. The direct current (100 kHz) when% is reduced is shown. This initial value is measured when the coil current is approximately 0A.

  In Comparative Example 1, Comparative Example 2, and Comparative Example 3, the curvature radii R are set to 11 μm, 17 μm, and 420 μm, respectively, and in Examples 1, 2, and 3, the curvature radii R are 30 μm, 83 μm, and 210 μm, respectively. Set to. In the coil parts according to Examples 1 to 3, there were almost no bubbles in the resin material 40 and the allowable current was 0.57 A or more. However, in the coil parts according to Comparative Examples 1 and 2, there were bubbles in the resin material 40. The allowable current is 0.51 A or less, and the coil component of Comparative Example 3 cannot be assembled.

  Next, an embodiment in which a part of the coil component 1 is modified will be described.

  In the above embodiment, the coil component 1 is formed by combining the upper ferrite core 11 having a C-shaped cross section and the lower ferrite core 12 having a T-shaped cross section, but other forms can also be adopted.

There are the following five viewpoints for configuring the coil component.
(I) To change the shape of the core (at least one of the upper ferrite core and the lower ferrite core).
(II) Changing the gap state between the upper ferrite core and the lower ferrite core.
(III) Changing the surface on which the coil is formed.
(IV) Changing the circular opening formed in the insulating plate.
(V) Changing the configuration of the core.

Sectional views in the vicinity of the center of the coil component of each embodiment from the viewpoint of the above (I) are shown in FIGS.
(Second Embodiment)

  FIG. 15 is a cross-sectional view of a coil component 1 in which a C-shaped upper ferrite core 11 and a C-shaped lower ferrite core 12 are combined.

  The difference between the coil component of this embodiment and the coil component of the first embodiment is that (A) the lower ferrite core 12 does not have a middle leg portion, and (B) the lower ferrite core 12 has an outer leg portion 122a. (C) The length of the outer leg 112 of the upper ferrite core 11 in the Z direction is shortened. Other configurations are the same as those of the coil component of the first embodiment. The coil base material 100 having the coil substrate 30 is disposed between the upper ferrite core 11 and the lower ferrite core 12 and includes planar coils 34 formed on both surfaces of the insulating plate 31.

The pair of outer leg portions 122a formed on the lower ferrite core 12 has the same structure as the outer leg portion 112, and each extends along the Y axis. The outer leg portion 122a and the outer leg portion 112 face each other, a gap is formed between them, and the adhesive resin material 40 is filled in the gap. The adhesive resin material 40 is filled between the protective resin layer 33 and the upper ferrite core 11 and the lower ferrite core 12.
(Third embodiment)

  FIG. 16 is a cross-sectional view of the coil component 1 in which a C-shaped upper ferrite core 11 and a I-shaped lower ferrite core 12 are combined.

The difference between the coil component 1 of the present embodiment and the coil component 1 of the first embodiment is that (A) the lower ferrite core 12 does not have a middle leg, and is bonded in the space where the middle leg exists. Resin 40 is filled. Other configurations are the same as those of the coil component of the first embodiment.
(Fourth embodiment)

  FIG. 17 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I-shaped cross section and a lower ferrite core 12 having a T-shaped cross section are combined.

The difference between the coil component 1 of the present embodiment and the coil component 1 of the first embodiment is that (A) the upper ferrite core 11 does not have an outer leg, and is bonded in the space where the outer leg exists. The resin material 40 is filled, and the side surface of the resin material 40 is exposed. Other configurations are the same as those of the coil component of the first embodiment.
(Fifth embodiment)

  FIG. 18 is a cross-sectional view of a coil component 1 in which a T-shaped upper ferrite core 11 and a T-shaped lower ferrite core 11 are combined.

  The difference between the coil component 1 of the present embodiment and the coil component 1 of the first embodiment is that (A) the upper ferrite core 11 has no outer legs, and (B) the upper ferrite core 11 has middle legs 113. (C) The Z-direction length of the middle leg portion 122 of the lower ferrite core 12 is shortened.

The middle leg 113 formed on the upper ferrite core 11 has the same structure as the middle leg 122 and protrudes in the Z direction. The middle leg portion 113 and the middle leg portion 122 are opposed to each other, a gap is formed between them, and the adhesive resin material 40 is filled in the gap. The space in which the outer leg portion is present is filled with the resin material 40 for adhesion, and the side surface of the resin material 40 is exposed. Other configurations are the same as those of the coil component of the first embodiment.
(Sixth embodiment)

  FIG. 19 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section E and a lower ferrite core 12 having a cross section C are combined.

The difference between the coil component 1 of the present embodiment and the coil component 1 of the second embodiment is that (A) there is a middle leg portion 113 projecting in the Z direction at the center of the upper ferrite core 11, and the others. Is the same as that of the coil component 1 of the second embodiment. A gap filled with the resin material 40 is formed between the middle leg portion 113 and the base portion 121 of the lower ferrite core 12.
(Seventh embodiment)

  FIG. 20 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I-shaped section and a lower ferrite core 12 having an E-shaped section are combined.

The difference between the coil component 1 of this embodiment and the coil component 1 of the first embodiment is that (A) the lower ferrite core 12 has an outer leg portion 122a, and (B) the upper ferrite core 11 protrudes in the Z direction. There is no outer leg portion extending in the Y direction. Other configurations are the same as those of the coil component of the first embodiment. The outer leg portion 122a faces the upper ferrite core 11, a gap is formed therebetween, and the adhesive resin material 40 is filled in the gap.
(Eighth embodiment)

  FIG. 21 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section E and a lower ferrite core 12 having a T section are combined.

The difference between the coil component 1 of this embodiment and the coil component 1 of the first embodiment is that (A) the middle leg portion 122 of the lower ferrite core 12 is short, and (B) the upper ferrite core 11 protrudes in the Z direction. The middle leg portion 113 is opposed to the middle leg portion 122. Other configurations are the same as those of the coil component 1 of the first embodiment. A gap is formed between the middle leg portion 122 and the middle leg portion 113, and the adhesive resin material 40 is filled in the gap.
(Ninth embodiment)

  FIG. 22 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section E and a lower ferrite core 12 having a cross section E are combined.

  The difference between the coil component of this embodiment and the coil component of the second embodiment is that (A) the lower ferrite core 12 has a middle leg portion 122 projecting in the Z direction, and (B) the upper ferrite core 11 has Z The middle leg portion 113 that protrudes in the direction and faces the middle leg portion 122. Other configurations are the same as those of the coil component of the second embodiment. A gap is formed between the middle leg portion 122 and the middle leg portion 113, and the adhesive resin material 40 is filled in the gap.

  Next, (II) changing the gap state between the upper ferrite core and the lower ferrite core will be described.

  FIG. 23 is an explanatory view of the vicinity of the contact portion when the cores are brought into contact with each other by closing the gap between the cores.

  In FIG. 23A, the base 121 of the lower ferrite core 12 and the outer leg 112 of the upper ferrite core 11 are in contact.

  In FIG. 23B, the middle leg portion 122 of the lower ferrite core 12 and the base portion 111 of the upper ferrite core 11 are in contact with each other.

  In FIG. 23C, the outer leg portion 122a of the lower ferrite core 12 and the outer leg portion 112 of the upper ferrite core 11 are in contact with each other.

  In FIG. 23D, the middle leg portion 122 of the lower ferrite core 12 and the middle leg portion 113 of the upper ferrite core 11 are in contact with each other.

  In FIG. 23E, the base 121 of the lower ferrite core 12 and the middle leg 113 of the upper ferrite core 11 are in contact.

  Any one or a plurality of contact states shown in FIGS. 23A to 23E can be applied to the first to ninth embodiments described above.

  In addition, it is preferable that at least one gap is formed in any part of the core structure including the upper ferrite core and the lower ferrite core. The outer leg extending from the upper ferrite core or any part between the protrusion and the lower ferrite core has a gap, or between the outer leg extending from the lower ferrite core or the protrusion and the upper ferrite core. It can be assumed that there is a gap in that part.

  Next, a modified example of the coil base material 100 including the coil substrate 30 and the protective resin layer 33 will be described.

  FIG. 24 is a longitudinal sectional view of the coil substrate 100.

  In FIG. 24A, the protective resin layer 33 is provided around the coil substrate 30 in which the planar coils 34 are provided on both surfaces of the insulating plate 31. A magnetic material can be mixed into the protective resin layer 33.

  In FIG. 24B, a protective resin layer 33 is provided around the coil substrate 30 in which the planar coil 34 is provided only on one side of the insulating plate 31. A magnetic material can be mixed into the protective resin layer 33.

  In FIG. 24C, the coil substrate 30 in which the planar coils 34 are provided on both surfaces of the insulating plate 31 is embedded in a protective resin layer 33x that does not contain a magnetic material, and the periphery of the protective resin layer 33x is made of a magnetic material. It is covered with the protective resin layer 33 contained.

  24D, in the coil substrate 30 in which the planar coil 34 is provided on both surfaces of the insulating plate 31, the top surface of the coil (see FIG. 13) is exposed in the protective resin layer 33x that does not contain a magnetic material. The protective resin layer 33x is covered with a protective resin layer 33 containing a magnetic material.

  In FIG. 24E, the coil substrate 30 in which the planar coils 34 are provided on both surfaces of the insulating plate 31 is embedded in a protective resin layer 33 containing a magnetic material, and the protective resin layer 33 is surrounded by a magnetic material. It is covered with a protective resin layer 33y that does not contain.

  In FIG. 24F, the coil substrate 30 in which the planar coils 34 are provided on both surfaces of the insulating plate 31 is embedded in the protective resin layer 33, and the outer periphery of the conductor of the planar coil 34 is roughened or oxidized. A Cu treatment layer 34a is formed. A magnetic material can be mixed into the protective resin layer 33.

  In FIG. 24G, the coil substrate 30 in which the planar coils 34 are provided on both surfaces of the insulating plate 31 is blackened on the outer periphery of the conductor and embedded in the protective resin layer 33x that does not contain a magnetic material. . The periphery of the protective resin layer 33x is covered with a protective resin layer 33 containing a magnetic material, and the protective resin layer 33 is covered with a protective resin layer 33y containing no magnetic material.

  The coil base material 100 shown in FIGS. 24A to 25G can be applied to the second and third embodiments.

  Further, a through hole H extending in the coil axis direction may be formed in the central portion of the coil base material 100.

  FIG. 25 is a longitudinal sectional view of the coil substrate 100 having the through hole H.

  The coil base material 100 shown in FIGS. 25 (A) to 25 (G) is provided with a through hole H in the central portion of the coil base material 100 shown in FIGS. 24 (A) to 24 (G). There are other configurations.

  The coil base material 100 shown in FIGS. 25 (A) to 25 (G) can be applied to the first to ninth embodiments described above, and the upper ferrite core 11 and / or the lower part are formed in the through hole. When the middle leg portion of the ferrite core 12 is located and there is no middle leg portion, the resin material 40 is filled.

  FIG. 26 is a longitudinal sectional view of the coil base 100 when the central opening of the insulating plate 31 is not formed.

  The coil base material 100 shown in FIGS. 26 (A) to 26 (G) has no opening in the central portion of the coil base material 100 shown in FIGS. 24 (A) to (G), that is, the insulating plate 31 is provided. It exists also in the central part, and other configurations are the same. In these cases, the step of forming the opening in the central portion can be omitted. The coil base material 100 shown in FIGS. 26 (A) to 26 (G) can be applied to the second and third embodiments described above.

  FIG. 27 is a longitudinal cross-sectional view of the coil base body 100 that does not form the central opening of the insulating plate 31 and has the through holes H that are partitioned vertically by the insulating plate 31.

  The coil base material 100 shown in FIGS. 27 (A) to 27 (G) is provided with a through hole H in the central portion of the coil base material 100 shown in FIGS. 26 (A) to 26 (G). There are other configurations.

  The coil base material 100 shown in FIGS. 27 (A) to 27 (G) can be applied to the above-described second, third, fifth, eighth, and ninth embodiments, and has a through hole. The upper ferrite core 11 and / or the lower ferrite core 12 has a middle leg portion, and the resin material 40 is filled in the case where there is no middle leg portion. When the two middle leg portions face each other, the insulating plate 31 that partitions the inside of the through hole H functions as a spacer that defines a gap therebetween.

  As described above, from the viewpoint of (IV) changing the circular opening formed in the insulating plate, a modification can be considered depending on whether the circular opening (center hole) of the coil substrate is provided or not. When the circular opening is not provided in the coil substrate, the step of opening the circular opening can be omitted, so that the coil component can be manufactured at a low cost. Moreover, since the gap can be formed by the coil substrate, the dimensional accuracy of the gap can be improved.

  In the coil base material 100 described above, the planar coil 34 may be formed only on one side, and this may be incorporated in a component.

  FIG. 28 is a longitudinal sectional view of the vicinity of the planar coil 34 of a coil component having the planar coil 34 only on one side.

  In FIG. 28A, the insulating plate 31 of the coil base material 100 is attached on the base 121 of the lower ferrite core 12 via the resin material 40, and the planar coil 34 is positioned thereon.

  In FIG. 28 (B), the insulating plate 31 of the coil base material 100 is attached under the base 111 of the upper ferrite core 11 via the resin material 40, and the planar coil 34 is located thereunder.

  In FIG. 28C, the insulating plate 31 of the coil base material 100 is embedded at an appropriate position between the upper ferrite core 11 and the lower ferrite core 12, and the planar coil 34 is positioned below the insulating plate 31. The remaining space between the upper ferrite core 11 and the lower ferrite core 12 is filled with a resin material.

  In the coil base material 100 described above, the planar coil 34 may be formed only on one side, and this may be formed directly on the core.

  FIG. 29 is a longitudinal sectional view of the vicinity of the planar coil 34 of a coil component having the planar coil 34 only on one side.

  In FIG. 29A, the planar coil 34 is directly formed on the base 121 of the lower ferrite core 12 via the base layer 60 a, and this is covered with the protective resin layer 33.

  In FIG. 29B, the planar coil 34 is directly formed on the lower surface of the base 111 of the upper ferrite core 11 via the base layer 60 a, and this is covered with the protective resin layer 33.

  In FIG. 29C, the planar coil 34 is directly formed on the base portion 121 of the lower ferrite core 12 via the base layer 60a, and this planar coil 34 is covered with an insulating layer 331, which is a protective resin layer. 33. On this insulating layer 331, another planar coil 34 is directly formed via a base layer 60a, and this is covered with a protective resin layer 33.

  Thus, (III) from the viewpoint of changing the surface on which the coil is formed, when forming the coil on one or both sides of the insulating plate, when directly forming the coil on the upper ferrite core or the lower ferrite core, A case where a coil is formed by multilayering through an insulating layer is conceivable. It is also conceivable to form a coil directly on the upper ferrite core or the lower ferrite core.

  In addition, the manufacturing method in the case where the coil 34 is directly formed on the upper ferrite core 11 or the lower ferrite core 12 may replace the insulating substrate 31 with the upper ferrite core 11 or the lower ferrite core 12, but will be briefly described below. deep.

First, a ferrite substrate having a thickness of 0.77 mm (which becomes the upper ferrite core 11 or the lower ferrite core 12) is prepared. One main surface (surface on which the coil 34 is formed) of this ferrite substrate is used instead of the insulating substrate 31, and a Cu film having a thickness of 0.1 to 1 μm is electrolessly plated to form a base conductor layer. Next, a photosensitive electrodeposition resist is formed and a spiral pattern to be the coil 34 is formed by photolithography, and electroplating is performed at a current density of 15 A / dm ² or less for about 20 minutes. A 35 μm Cu conductor pattern is formed.

  After removing the selective plating mask resist, the underlying conductor layer is etched and second electroplating is performed with a predetermined current profile to form, for example, a Cu conductor pattern having a height of 75 μm and a width of 65 μm. The surface is coated by mask printing with a solder ink resist except for the center of the spiral. Further, Cr and Cu are continuously formed on this solder ink resist by a mask sputtering method, and an electrode is taken out from the spiral central portion. As a result, a ferrite wafer (an assembly of the lower ferrite cores 12) in which the coils 34r are aligned can be manufactured.

  The ferrite wafer and the ferrite substrate are bonded using an epoxy adhesive while being pressed in a 150 ° C. atmosphere. The bonded substrate is ground flat to a thickness of 0.77 mm with a high-precision slicer, and then chipped with a dicer to produce each element.

  Thereafter, in order to form an external terminal electrode to be a user terminal for circuit connection, after barrel polishing, the terminal surface Cu (leading end electrode portion) is cleaned using both wet processing and dry processing, Cr and Cu are continuously formed by mask sputtering. This is subjected to barrel plating of Cu, Ni, and Sn to produce a coil component 1r which is a surface-mounted coil element having a product size of 3 mm long × 2.6 mm wide × 0.8 mm high.

  The area of the insulating plate 31 of the coil base material 100 described above may be greater than or equal to the maximum cross-sectional area in the XY plane of the lower ferrite core 12. In this case, the insulating plate 31 is opposed to the outer leg portion. It can be made to intervene between the base portion or the outer leg portion to function as a spacer constituting a gap between the cores. Moreover, in the case of the coil base material 100 which has the insulating plate 31 which partitions the through-hole H formed in the center part, the insulating plate 31 for a partition is made into a middle leg part, and the base or middle leg part which opposes this. And function as a spacer constituting a gap between the cores.

  FIG. 30 is a cross-sectional view of the periphery of the insulating plate 31 when the insulating plate 31 functions as a spacer.

  In FIG. 30A, the insulating plate 31 is interposed between the outer leg portion 112 of the upper ferrite core 11 and the base portion 121 of the lower ferrite core 12, and the thickness of the insulating plate 31 defines the gap between the cores. .

  This is a case where the area of the insulating plate 31 is equal to or larger than the maximum cross-sectional area in the XY plane of the lower ferrite core 12, and the planar coil 34 is formed only on one side (FIGS. 24B and 28A). ), FIG. 28 (B), FIG. 28 (C)), and can be applied when the core shape is the first, third, or eighth embodiment. However, the planar coil 34 is located above the insulating plate 31. In addition, the opening of the center part of the insulating plate 31 may or may not exist when the core shape is the third embodiment, and must exist when the core shape is the first and eighth embodiments. .

  In FIG. 30B, the insulating plate 31 is interposed between the base 111 of the upper ferrite core 11 and the middle leg portion 122 of the lower ferrite core 12, and the thickness of the insulating plate 31 defines the gap between the cores. .

  This is applicable regardless of whether the area of the insulating plate 31 is greater than or less than the maximum cross-sectional area in the XY plane of the lower ferrite core 12. Further, the present invention can be applied only to the configuration in which the planar coil 34 is formed on one side (FIG. 24B, FIG. 28A, FIG. 28B, and FIG. 28C). However, the planar coil 34 is located below the insulating plate 31. The present invention can be applied when the core shape is the fourth or seventh embodiment. Note that no opening is formed in the central portion of the insulating plate 31.

  In FIG. 30C, the insulating plate 31 is interposed between the middle leg portion 122 of the lower ferrite core and the middle leg portion 113 of the upper ferrite core, and the thickness of the insulating plate 31 defines the gap between the cores. .

  This is applicable regardless of whether the area of the insulating plate 31 is greater than or less than the maximum cross-sectional area in the XY plane of the lower ferrite core 12. Further, the present invention is applicable to any form in which the planar coil 34 is formed on one side (FIG. 24B, FIG. 28A, FIG. 28B, FIG. 28C), or on both sides. it can. In the case of single-sided formation, the planar coil 34 may be located on either the upper side or the lower side of the insulating plate 31. The present invention can be applied when the core shape is the fifth, eighth, or ninth embodiment. Note that no opening is formed in the central portion of the insulating plate 31.

  In FIG. 30D, the insulating plate 31 is interposed between the base portion 121 of the lower ferrite core and the middle leg portion 113 of the upper ferrite core, and the thickness of the insulating plate 31 defines the gap between the cores.

  This is applicable regardless of whether the area of the insulating plate 31 is greater than or less than the maximum cross-sectional area in the XY plane of the lower ferrite core 12. Further, the present invention can be applied only to the configuration in which the planar coil 34 is formed on one side (FIG. 24B, FIG. 28A, FIG. 28B, and FIG. 28C). The planar coil 34 is located above the insulating plate 31. The present invention can be applied when the core shape is the sixth embodiment. Note that no opening is formed in the central portion of the insulating plate 31.

  In FIG. 30E, the insulating plate 31 is interposed between the outer leg portion 122a of the lower ferrite core and the outer leg portion 112 of the upper ferrite core, and the thickness of the insulating plate 31 defines the gap between the cores. .

  This is applicable when the area of the insulating plate 31 is greater than or equal to the maximum cross-sectional area in the XY plane of the lower ferrite core 12. Further, the present invention is applicable to any form in which the planar coil 34 is formed on one side (FIG. 24B, FIG. 28A, FIG. 28B, FIG. 28C), or on both sides. it can. In the case of single-sided formation, the planar coil 34 may be located on either the upper side or the lower side of the insulating plate 31. The present invention can be applied when the core shape is the second, sixth, or ninth embodiment. In the case of the second embodiment, the opening of the central portion of the insulating plate 31 may or may not exist. In the case of the sixth embodiment, the opening of the central portion of the insulating plate 31 is formed. In the case of the embodiment, the opening in the central portion of the insulating plate 31 may or may not exist.

  In FIG. 30F, the insulating plate 31 is interposed between the outer leg portion 122a of the lower ferrite core and the base portion 111 of the upper ferrite core, and the thickness of the insulating plate 31 defines the gap between the cores.

  This is applicable when the area of the insulating plate 31 is greater than or equal to the maximum cross-sectional area in the XY plane of the lower ferrite core 12. Further, the present invention can be applied only to the configuration in which the planar coil 34 is formed on one side (FIG. 24B, FIG. 28A, FIG. 28B, and FIG. 28C). The planar coil 34 is located below the insulating plate 31. This can be applied when the core shape is the seventh embodiment. In the case of the seventh embodiment, an opening in the central portion of the insulating plate 31 is formed.

  Next, a characteristic structure among the combinations of the above-described embodiments and cores will be described.

  FIG. 31 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I-shaped cross section and a lower ferrite core 12 having a T-shaped cross section are combined.

  In the coil component 1 of this example and the coil component 1 shown in FIG. 17 (fourth embodiment), the upper ferrite core 11 and the middle leg portion 122 of the lower ferrite core 12 are in contact with each other, and no gap is formed. It is different in point. Therefore, although the coil substrate 30 and the protective resin layer 33 are the same as those of the coil component 1 of FIG. 17, the adhesive resin material 40 is not filled in the gap in this example.

  FIG. 32 is a cross-sectional view of the coil component 1 in which the coil substrate 30 of the coil component 1 shown in FIG. 31 is changed to a one-side coil-formed coil substrate 30.

  The coil 34 is formed only on one surface of the insulating plate 31 of the coil substrate 30. Therefore, the resin material 40 disposed between the upper ferrite core 11 and the lower ferrite core 12 is in close contact with the surface of the insulating plate 31 where the coil 34 is not formed.

  FIG. 33 is a cross-sectional view of the coil component 1 from which the circular opening of the coil substrate 30 is eliminated.

  In this example, the coil substrate 30 used for the coil component 1 is not formed with a circular opening as a center hole. Therefore, the coil substrate 30 is sandwiched between the upper ferrite core 11 and the lower ferrite core 12, and a gap is formed between the upper ferrite core 11 and the lower ferrite core 12 by the insulating plate 31 of the coil substrate 30. Is done. The protective resin layer 33 disposed between the upper ferrite core 11 and the lower ferrite core 12 is in close contact with the surface of the insulating plate 31 on which the coil 34 is formed. Further, the adhesive resin material 40 wraps around the surface of the insulating plate 31 where the coil 34 is not formed, and fixes the upper ferrite core 11d and the coil substrate 30.

  FIG. 34 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I cross section and a lower ferrite core 12 having a T cross section are combined.

  The planar coil 34 is formed directly on the lower ferrite core 12. Therefore, the protective resin layer 33 is disposed so as to cover the planar coil 34 formed directly on the lower ferrite core 12. In this state, the adhesive resin material 40 is disposed so as to fix the upper ferrite core 11 and the lower ferrite core 12.

  FIG. 35 is a cross-sectional view of a coil component 1 in which a T-shaped upper ferrite core 11 and a T-shaped lower ferrite core 12 are combined.

  The coil component 1 of this example is different only in that the coil substrate 30 of the coil component shown in FIG. 18 (fifth embodiment) does not have a circular opening as a center hole. Therefore, the insulating plate 31 of the coil substrate 30 is sandwiched between the protrusion 113 of the upper ferrite core 11 and the middle leg portion 122 of the lower ferrite core 12, and the upper ferrite core 11 and the lower ferrite core 12 are A gap is formed between them by the insulating plate 31 of the coil substrate 30. The protective resin layer 33 disposed between the upper ferrite core 11 and the lower ferrite core 12 is disposed so as not to enter the gap.

  FIG. 36 is a cross-sectional view of the coil component 1 in which the core is configured only by the T-shaped lower ferrite core 12.

  In this example, the upper ferrite core 11 is removed from the coil component 1 shown in FIG. 17 (fourth embodiment). That is, the upper surface of the resin 40 is exposed. Thus, from the viewpoint of changing the configuration of the (V) core, it is conceivable that the coil component is configured only by the lower ferrite core. Furthermore, the cross-sectional shape of the lower ferrite core can be changed to a T-shaped cross section, a C-shaped cross section, or an E-shaped cross section.

  FIG. 37 is a cross-sectional view of the coil component 1 in which the core is configured by only the lower ferrite core 12 having an E-shaped cross section.

  In this example, the upper ferrite core 11 is removed from the coil component 1 shown in FIG. 20 (seventh embodiment).

  FIG. 38 is a cross-sectional view of the coil component 1 in which the core is configured only by the lower ferrite core 12 having a C-shaped cross section.

  In this example, the structure is obtained by removing the middle leg portion 122 from the coil component 1 shown in FIG. Resin 40 is filled in the removed space.

  Also in the above-described modification, a Cu treatment layer (not shown) is formed on the surface of the planar coil 34, and a boundary surface subjected to R processing or C processing is formed between the base portion and the outer leg portion or the middle leg portion. The top surface of the planar coil 34 is assumed to be flattened. Note that the description of the external terminal 20 is omitted in the modification. Further, when the above-described adhesive resin material 40 and the protective resin layer 33 are made of a resin containing ferrite, desired inductor characteristics can be obtained by the configuration of the coil substrate and the ferrite core.

It is a perspective view of the coil component 1 in this embodiment. 2 is an exploded perspective view of a coil structure 10. FIG. FIG. 2 is a perspective view of a coil component in a state where an external terminal 20 is removed from the state of FIG. 1. 3 is a plan view of a coil substrate 30. FIG. It is a VV arrow sectional view (longitudinal sectional view) of coil component 1 shown in FIG. 6 is a diagram for explaining a method of manufacturing the coil substrate 30. FIG. 6 is a diagram for explaining a method of manufacturing the coil substrate 30. FIG. It is a block diagram of the film-forming apparatus 8 used when forming an electrolytic plating film. FIG. 6 is an enlarged view of a region A1 shown in FIG. It is an enlarged view of the modification of area | region A1 shown in FIG. FIG. 6 is an enlarged view of a region A2 shown in FIG. It is an enlarged view of the modification of area | region A2 shown in FIG. 3 is a longitudinal section of a conductor wire perpendicular to the direction in which the conductor wire constituting the planar coil 34 extends. It is a table | surface which shows the above-mentioned curvature radius R, the number of bubbles in the resin material 40, and an allowable electric current (A). 1 is a cross-sectional view of a coil component 1 in which a C-shaped upper ferrite core 11 and a C-shaped lower ferrite core 12 are combined. 1 is a cross-sectional view of a coil component 1 in which a C-shaped upper ferrite core 11 and a I-shaped lower ferrite core 12 are combined. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I-shaped section and a lower ferrite core 12 having a T-shaped section are combined. 2 is a cross-sectional view of a coil component 1 in which a T-shaped upper ferrite core 11 and a T-shaped lower ferrite core 11 are combined. FIG. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section E type and a lower ferrite core 12 having a cross section C type are combined. FIG. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section I and a lower ferrite core 12 having a cross section E are combined. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section E and a lower ferrite core 12 having a T section are combined. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having a cross section E and a lower ferrite core 12 having a cross section E are combined. FIG. It is explanatory drawing of the contact part vicinity at the time of closing the gap between cores and contacting cores. 1 is a longitudinal sectional view of a coil substrate 100. FIG. 2 is a longitudinal sectional view of a coil substrate 100 having a through hole H. FIG. FIG. 3 is a longitudinal sectional view of a coil base body 100 when a central opening of an insulating plate 31 is not formed. FIG. 3 is a longitudinal sectional view of a coil base body 100 having a through hole H that is not formed with a central opening of an insulating plate 31 and that is vertically partitioned by the insulating plate 31. It is a longitudinal cross-sectional view of the planar coil 34 vicinity of the coil component provided with the planar coil 34 only on one side. It is a longitudinal cross-sectional view of the planar coil 34 vicinity of the coil component provided with the planar coil 34 only on one side. It is sectional drawing of the peripheral part of the insulating board 31 in the case of making the insulating board 31 function as a spacer. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I-shaped cross section and a lower ferrite core 12 having a T-shaped cross section are combined. It is sectional drawing of the coil component 1 which changed the coil board | substrate 30 of the coil component 1 shown in FIG. 31 into the coil board | substrate 30 of one-side coil formation. 2 is a cross-sectional view of the coil component 1 in which a circular opening of the coil substrate 30 is eliminated. FIG. 1 is a cross-sectional view of a coil component 1 in which an upper ferrite core 11 having an I-shaped cross section and a lower ferrite core 12 having a T-shaped cross section are combined. 2 is a cross-sectional view of a coil component 1 in which a T-shaped upper ferrite core 11 and a T-shaped lower ferrite core 12 are combined. FIG. 1 is a cross-sectional view of a coil component 1 in which a core is constituted only by a T-shaped lower ferrite core 12. 1 is a cross-sectional view of a coil component 1 in which a core is constituted only by an E-shaped lower ferrite core 12. 1 is a cross-sectional view of a coil component 1 in which a core is constituted only by a C-shaped lower ferrite core 12.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Coil component, 10 ... Core structure, 11 ... Upper ferrite core, 12 ... Lower ferrite core, 20 ... External terminal, 30 ... Coil board | substrate, 31 ... Insulating plate, 32 ... Derived end electrode, 33 ... Protective resin layer, 34 ... Coil conductors, 36 ... Front and back contact parts, 40 ... Resin material for adhesion.

Claims (5)

A core having a protruding portion erected from a flat base, and
A planar coil facing the core;
A resin material interposed between the core and the planar coil;
In coil parts with
The protrusion is located inside the planar coil;
The boundary surface between the base and the protrusion is
A curved surface having a radius of curvature of 30 μm or more in a plane passing through the center of the planar coil and along the thickness direction of the base, or
In the plane, the plane is inclined with respect to the main plane of the base, and the minimum value of the length of the line segment constituting the intersection line between the boundary plane and the plane is 30 μm or more
Coil parts characterized by being. A core having first and second protrusions erected from a flat base,
A planar coil facing the core;
A resin material interposed between the core and the planar coil;
In coil parts with
The planar coil is located between the first and second protrusions,
Each of the boundary surfaces between the base and the first and second protrusions is
A curved surface having a radius of curvature of 30 μm or more in a plane passing through the center of the planar coil and along the thickness direction of the base, or
In the plane, the plane is inclined with respect to the main plane of the base, and the minimum value of the length of the line segment constituting the intersection line between the boundary plane and the plane is 30 μm or more
Coil parts characterized by being. A first core having a first protruding portion erected from a flat plate-like first base;
A second core having second and third protrusions erected from a flat plate-like second base;
A planar coil located between the first and second cores;
A resin material interposed between the first and second cores and the planar coil;
In coil parts with
The first protrusion is located inside the planar coil;
The planar coil is located between the second and third protrusions,
The boundary surface between the first base and the first protrusion is
A curved surface having a radius of curvature of 30 μm or more in a plane passing through the center of the planar coil and along the thickness direction of the first base, or
In the plane, the plane is inclined with respect to the main plane of the first base, and the minimum value of the length of the line segment constituting the intersection line between the boundary plane and the plane is 30 μm or more,
Coil parts characterized by being. A first core having a first protruding portion erected from a flat plate-like first base;
A second core having second and third protrusions erected from a flat second base;
A planar coil located between the first and second cores;
A resin material interposed between the first and second cores and the planar coil;
In coil parts with
The first protrusion is located inside the planar coil;
The planar coil is located between the second and third protrusions,
Each of the boundary surfaces of the second base and the second and third protrusions is
A curved surface having a radius of curvature of 30 μm or more in a plane passing through the center of the planar coil and along the thickness direction of the second base, or
In the plane, the plane is inclined with respect to the main plane of the second base, and the minimum value of the length of the line segment constituting the intersection line between the boundary plane and the plane is 30 μm or more,
Coil parts characterized by being. 5. The coil component according to claim 1, wherein an application area of the resin material on the main surface of the base perpendicular to the protrusion is 20 mm ² or less.

Images