JP2008218950A - Surface-mounting coil component and method for manufacturing surface-mounting coil component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounting coil component which can prevent falling off due to exfoliation of a part of a resin coating, moisture infiltration in air from an interface thereof, and the like. <P>SOLUTION: The surface-mounting coil component has a substrate 11, which has a plurality of connection electrodes 12a in one principal surface 11a and has a plurality of terminal electrodes 12b which is connected to the connection electrodes, respectively, in the other principal surface 11b; a core 13 which has a wound core part 14 and a pair of guards 15 and 16 provided in an upper part and a lower part of the wound core part 14, and in which a lower surface 16b of the lower guard is fixed firmly to one principal surface 11a of the substrate; and a coil conductor 17 which is wound around the wound core part of the core and whose end parts 17a and 17b are connected to the connection electrodes of the substrate, respectively. A tapered part TP is formed toward the periphery of the guard in an upper surface 15a of the upper guard of the core, and the core including the taper part and the side of one principal surface of the substrate is covered with the resin coating 18. As a result of this, shear force applied to an interface between the upper surface of the upper guard of the core and the covered resin coating is dispersed, and the exfoliation is less likely to occur in the interface. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a winding type surface-mounted coil component used for portable electronic devices, thin electronic devices, and the like, and a method for manufacturing the surface-mounted coil component.

As a coil component such as a choke coil used for a DC / DC power supply of a portable electronic device such as a portable phone or a digital still camera or a peripheral circuit of various flat panel displays, etc., while ensuring desired inductor characteristics There is a need for a small and low profile surface mount coil component that can be mounted with high density or low profile.

Since the portable electronic device is used by taking it outdoors or on the go, the temperature change of the environment is remarkable, and it is expected that the user will accidentally drop it. For this reason, in the surface mount type coil component for the above-described use, reliability with respect to temperature change and reliability with respect to impact are required.

Patent Document 1 discloses an SMD type coil package in which a bobbin in which a coil winding is wound is mounted on the surface of a substrate as the above-described coil component. As shown in FIG. 6, in Patent Document 1, a drum-shaped bobbin 103 is fixed on a substrate 101, and a coil winding 107 is wound around the bobbin 103, and an end 107a of the coil winding 107 is formed. Has been proposed that is connected to the wiring pattern 102 of the substrate 101. As shown in FIG. 7, in Patent Document 1, a drum-shaped bobbin 203 is fixed together with other electronic components EP on a substrate 201, and a coil winding 207 is wound around the bobbin 203. The SMD type coil package 200 is provided with an end portion 207a of the coil winding 207 connected to the wiring pattern 202a of the substrate 201 and a resin sheath 208 that covers one side of the bobbin 203 and the substrate 201. Has been proposed.
JP 2006-13054 A

In the SMD type coil package 200 described in the background art, since the upper surface of the flange 205 above the drum-shaped bobbin 203 is formed flat, the upper surface of the upper flange 205 and the resin sheath 208 An interface formed by a single plane occupying a large proportion of the planar dimensions of the SMD type coil package 200 is formed between the surface and the surface. Therefore, when the SMD type coil packages 200 are in contact with each other, or when the upper surface of the coil package 200 and the cover tape of the carrier tape are in contact with each other in the component storage chamber of the carrier tape that accommodates the SMD type coil package 200, the SMD type Shear force concentrates on the interface between the resin sheath 208 of the die coil package 200 and the upper surface of the flange 205 above the bobbin 203, and at the interface, the upper surface of the flange 205 above the bobbin 203 and the resin sheath 208 Peeling from the surface was easy to occur. For this reason, there is a problem that part of the resin sheath 208 falls off or moisture in the air easily enters the peeled interface.

An object of the present invention is to provide a surface-mounting coil component that solves the above-described problems and can prevent dropping of a sheathed resin due to peeling or intrusion of moisture in the air from an interface. . Another object of the present invention is to provide a manufacturing method capable of stably producing a surface-mounting coil component that hardly causes peeling of an external resin.

In order to achieve the above object, a surface-mounted coil component according to the present invention has (1) a plurality of connection electrodes on one main surface and a plurality of terminal electrodes respectively connected to the connection electrodes on the other main surface. A core having a substrate, a winding core portion, and a pair of flanges provided above and below the winding core portion, and a lower surface of the lower flange fixed to one main surface of the substrate; In a surface mount type coil component having a coil conductor wound around the winding core portion and each end portion of which is connected to a connection electrode of the substrate, the outer periphery of the flange is placed on the upper surface of the flange above the core. A taper portion is formed toward the surface, and a core around which the coil conductor including the taper portion is wound and one main surface side of the substrate are covered with a resin sheath. (... hereinafter referred to as first problem solving means)

One of the main forms of the surface mount type coil component is as follows. (2) The tapered portion is formed in part toward the outer periphery of the ridge above the core. (... hereinafter referred to as second problem solving means)

The other main forms of the surface mount type coil component are as follows: (3) The core has the upper ridge formed in a shade shape with respect to the core portion. (... hereinafter referred to as third problem solving means)

In addition, the method for manufacturing the surface mount type coil component according to the present invention includes (4) a winding core portion and a pair of hooks provided above and below the winding core portion. A step of preparing a plurality of cores having tapered portions toward the outer periphery, and a lower surface of the lower ridge on each main surface of the collective substrate capable of taking a large number of substrates having a plurality of terminal electrodes Mounting the plurality of cores so that they are in contact with each other, winding coil conductors sequentially around the cores on the collective substrate, and connecting the end portions of the coil conductors to connection electrodes connected to the terminal electrodes of the substrate, respectively Applying resin by vacuum printing so as to cover the step of connecting by thermocompression bonding, a plurality of cores around which the coil conductor including the tapered portion is wound and one main surface side of the collective substrate, and covering the resin sheath Forming process and resin exterior By dividing the the collective substrate by dicing are those having a step of obtaining a plurality of surface mount type coil component, a. (... hereinafter referred to as fourth problem solving means)

The operation of the first problem solving means is as follows. That is, a substrate having a plurality of connection electrodes on one main surface and a plurality of terminal electrodes respectively connected to the connection electrodes on the other main surface, a core portion, and an upper portion and a lower portion of the core portion. And a core having a lower surface of the lower collar fixed to one main surface of the substrate, and an end portion of the core being wound around the core portion of the core. A coil conductor connected to the connection electrode, wherein the coil includes a taper portion formed on an upper surface of the ridge above the core toward the outer periphery of the ridge and the tapered portion Since the core on which the conductor is wound and one main surface side of the substrate are covered with a resin sheath, the upper surface of the upper ridge and the resin that occupy a large proportion of the planar dimensions of the surface-mounted coil component Boundary with exterior surface There has been a three-dimensional ones having the tapered portion. For this reason, in the contact between the surface mount type coil components and the contact between the upper surface of the surface mount type coil component and the cover tape in the storage space of the carrier tape that stores the surface mount type coil component, The shearing force applied to the interface between the upper surface of the ridge and the coated resin sheath is dispersed, and peeling is unlikely to occur at the interface. For this reason, it is possible to prevent falling off due to part of the resin sheathing and intrusion of moisture in the air from the interface.

The operation of the second problem solving means is as follows. That is, since the tapered portion is formed in part toward the outer periphery of the ridge above the core, the core and the substrate including the tapered portion can be accurately held by suction when the core is mounted on the substrate. Since the screen mask can be prevented from being damaged when the exterior resin is applied by the vacuum printing method so as to cover one main surface side, it is suitable for stable production.

The operation of the third problem solving means is as follows. That is, since the core is formed by providing the upper hook in a shade shape with respect to the core portion, an increase in the thickness of the hook can be avoided and a thin coil component can be provided.

The operation of the fourth problem solving means is as follows. That is, a plurality of cores having a winding core portion and a pair of ridges provided above and below the winding core portion and having a tapered portion formed on the upper surface of the upper ridge toward the outer periphery of the ridge are prepared. A step of mounting the plurality of cores such that a lower surface of the lower ridge is in contact with one main surface of an aggregate substrate capable of taking a large number of substrates having a plurality of terminal electrodes, and the assembly A step of winding a coil conductor sequentially around a core on a substrate and connecting an end portion of the coil conductor to a connection electrode connected to the terminal electrode of the substrate by thermocompression bonding; and the coil conductor including the taper portion A step of applying a resin by a vacuum printing method so as to cover a plurality of cores wound with a core and one main surface side of the collective substrate, and a collective substrate on which the resin sheath is formed by dicing Divide and duplicate Obtaining a surface mount coil part, because it has a, it is possible to stably produce an interface peeling is hard surface mount type coil component which occur between the upper flange and the outer resinous core.

According to the surface mount type coil component of the present invention, the contact between the surface mount type coil components and the upper surface of the surface mount type coil component in the storage space of the carrier tape storing the surface mount type coil component and the cover tape At the time of contact, it is possible to prevent a part of the resin sheath from falling off due to peeling, moisture in the air from the interface, and the like. In addition, according to the method of manufacturing a surface-mounting coil component of the present invention, it is possible to stably produce a surface-mounting coil component in which peeling is unlikely to occur at the interface between the ridge above the core and the sheathed resin. The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

Hereinafter, a first embodiment of a surface mount coil component of the present invention will be described with reference to FIG. FIG. 1 is a longitudinal sectional view for explaining the overall structure of the surface mount type coil component 10 of the first embodiment.

As shown in FIG. 1, the surface mount type coil component 10 of the present embodiment includes a substrate 11, a drum-shaped core 13, a coil conductor 17 wound around the core 13, and a resin sheath 18 that covers the core 13. I have it. Specifically, a substrate 11 having a plurality of connection electrodes 12a on one main surface 11a and a plurality of terminal electrodes 12b connected to the connection electrodes 12a on the other main surface 11b, a core portion 14, A core 13 having a pair of flanges 15 and 16 provided above and below the core part 14 and having a lower surface 16b of the lower flange 16 fixed to one main surface 11a of the substrate 11; 13 is a surface-mounting coil component 10 having coil conductors 17 wound around the winding core portion 14 and having end portions 17a and 17b connected to connection electrodes 12a and 12a of the substrate 11, respectively. A taper portion TP is formed on the upper surface 15a of the flange 15 above the core 13 toward the outer periphery of the flange 15, and the core 13 and the coil conductor 17 including the taper portion TP are wound thereon. One main 11a side of the substrate 11 is covered with a resin sheath 18. More specifically, the substrate 11 has a plurality of connection electrodes 12a, 12a on one main surface 11a, and is connected to the connection electrode 12a via a through-hole conductor 12c, respectively, on the other main surface 11b. It has a plurality of terminal electrodes 12b. The drum-shaped core 13 includes the core portion 14 and a pair of flanges 15 and 16 having a square shape in plan view provided above and below the core portion 14. A taper portion TP is formed on the upper surface 15a of the upper flange 15 toward the outer periphery of the flange 15. The coil conductor 17 is wound around the core 14 of the core 13 and the ends 17a and 17b are connected to the connection electrodes 12a and 12a of the substrate 11 by thermocompression bonding, respectively. The core 13 around which the coil conductor 17 including the tapered portion TP is wound and the one main surface 11a side of the substrate 11 are covered with a resin sheath 18.

Further, in the surface mount type coil component 10 of the present embodiment, the tapered portion TP is formed in part toward the outer periphery of the flange 15 above the core 13.

In the surface mount type coil component 10 of the present embodiment, a taper portion in which the interface between the upper surface 15a of the upper flange 15 of the core 13 and the coated resin sheath 18 is formed toward the outer periphery of the upper flange 15. Distributed in multiple directions by TP. For this reason, the surface-mounted coil components 10 are in contact with each other, or the upper surface of the surface-mounted coil component 10 and the carrier tape are placed in a component storage recess of a carrier tape (not shown) that stores the surface-mounted coil component 10. When the cover tape comes into contact, the shearing force applied to the interface is dispersed, and peeling is unlikely to occur at the interface. For this reason, it is possible to prevent the resin sheathing 18 from falling off due to peeling, and intrusion of moisture in the air from the interface.

A preferred embodiment of the substrate 11 is as follows. That is, as the substrate 11, a ceramic substrate made of alumina, other ceramics, a resin substrate made of glass epoxy resin, paper phenol resin, or the like, or other various insulating substrates can be used. Moreover, the said board | substrate 11 is not limited to a single layer thing, The thing by which the layer of the single material was laminated | stacked two or more, and the layer by which the mutually different material layer was laminated | stacked alternately may be used. Further, the substrate 11 may have a wiring pattern. The outer dimensions of the substrate 11 are preferably formed to have a width of about 3.2 mm, a length of 3.2 mm, and a thickness of about 0.2 mm, for example. Further, the collective substrate 11A for taking a large number of the substrates 11 is preferably formed to have a width of about 100 mm, a length of 100 mm, and a thickness of about 0.2 mm, for example. The substrate 11 preferably has a plurality of connection electrodes 12a on one main surface 11a side. The substrate 11 preferably has a plurality of terminal electrodes 12b connected to the connection electrodes 12a on the other main surface 11b side. Next, a preferred embodiment of the connection electrode 12a is as follows. That is, it is preferable that a plurality of the connection electrodes 12a are arranged on the one main surface 11a side of the substrate so as to be spaced apart from each other around a region where a core 13 to be described later is fixed. The connection electrode 12a is preferably made of Ag, Cu, other highly conductive metals, or alloys thereof. The connection electrode 12a is preferably formed in a rectangular shape with a width of 0.5 mm and a length of 2.0 mm, for example, with a thickness of about 0.1 mm. The formation of the connection electrode 12a on the one main surface 11a of the substrate 11 is preferably performed by patterning a metal foil attached to the one main surface 11a side of the substrate 11 by etching, but is not limited thereto. For example, the surface of the substrate 11 may be formed by plating. When a ceramic substrate is used as the substrate 11, an electrode material paste mainly composed of the highly conductive metal or the like is applied to one main surface 11 a side of the substrate 11 by screen printing or the like. The thick film conductor may be formed by baking at a temperature of Next, a preferred embodiment of the terminal electrode 12b is as follows. That is, the terminal electrode 12b is disposed on the other main surface 11b side of the substrate 11 in the vicinity of a position where the connection electrode 12a on the one main surface 11a side and the substrate 11 are opposed to each other. It is preferred that The terminal electrode 12b is preferably made of Ag, Cu, other highly conductive metals or alloys thereof. The terminal electrode 12b is formed on the other main surface 11b of the substrate 11 simultaneously with the connection electrode 12a on the one main surface 11a side of the substrate 11 by means similar to the connection electrode 12a. It is preferable. The terminal electrode 12b is preferably formed in a rectangular shape having a width of 1.0 mm and a length of 3.0 mm, for example, with a thickness of about 0.1 mm, and the surface is coated with solder plating or the like as necessary. Is preferred.

The connection between the terminal electrode 12b and the connection electrode 12a is formed by, for example, providing a through hole penetrating the substrate 11 in the thickness direction and filling the through hole with a conductive material such as a plating film or a conductive resin. The through-hole conductor 12c is preferably connected.

Next, a preferred embodiment of the core 13 is as follows. That is, the core 13 preferably has a core portion 14 and a pair of flanges 15 and 16 above and below the core portion 14, and on the upper surface of the upper flange 15 on the outer periphery of the flange 15. It is preferable that a tapered portion TP is formed. Further, the core 13 is not limited to the one having the tapered portion TP only on the upper surface 15a side of the upper collar 15, and for example, the upper collar is formed in a shade shape with respect to the core portion. There may be. The core 13 can be appropriately selected from various soft magnetic materials. For example, a high permeability magnetic material mainly composed of Mn—Zn ferrite, Ni—Zn ferrite, Ni—Zn—Cu ferrite and the like is more preferable.

Next, a preferred embodiment of the core part 14 of the core 13 is as follows. That is, the winding core portion 14 is preferably substantially circular or circular in cross section so that the length of the coil conductor necessary for obtaining a predetermined number of turns can be shortened, but is not limited thereto. In particular, in the case of producing by a method of obtaining a drum-shaped molded body by dry integral molding, it can be appropriately changed in consideration of the durability of the mold and the ease of deburring. Specifically, for example, a columnar shape having a radius of 0.3 mm and a height of 0.4 mm is preferable, but is not limited thereto. For example, the cross section may be a substantially square shape having a side of 0.5 mm. . Next, a preferred embodiment of the flange 16 below the core 13 is as follows. That is, as the lower ridge 16, the shape in plan view is preferably a substantially quadrangular shape or a quadrangular shape in order to reduce the size in correspondence with high-density mounting, but the shape is not limited to this. It may be. Specifically, the shape of the plan view having a width of 2.5 mm, a length of 2.5 mm, and a thickness of 0.2 mm is preferably a square shape, but is not limited to this, for example, a radius of 1.2 mm, a thickness of The planar view shape with a thickness of 0.2 mm may be circular. Next, a preferred embodiment of the flange 15 above the core 13 is as follows. That is, the upper flange 15 is preferably a substantially quadrangular or quadrangular shape in plan view in order to reduce the size in correspondence with high-density mounting, but is not limited thereto, and is not limited to this. It may be. A similar shape is preferable corresponding to the lower ridge 16, and the same size as the lower ridge 16 or a slightly smaller size than the lower ridge 16 is preferable. Further, it is preferable to chamfer the four corners of the upper collar 15 in order to facilitate interposition of the resin sheathing 18 described later between the collars. Specifically, the shape of the plan view having a width of 2.5 mm, a length of 2.5 mm, and a thickness of 0.2 mm is preferably a square shape, but is not limited to this, for example, a radius of 1.2 mm, a thickness of The planar view shape with a thickness of 0.2 mm may be circular.

Next, a preferred embodiment of the coil conductor 17 is as follows. That is, the coil conductor 17 is wound around the core portion 14 of the core 13 and is preferably an insulation-coated conductor, such as a polyurethane resin-coated copper wire, a polyester resin-coated copper wire, or an enamel resin-coated wire. Copper wire or the like is more preferable. The metal wire of the coil conductor 17 is not limited to a single wire, and may be a stranded wire. The metal wire of the coil conductor 17 is not limited to a circular cross-sectional shape, and a rectangular wire having a rectangular cross-sectional shape, a square wire having a square cross-sectional shape, or the like may be used. Moreover, you may use the self-bonding wire which coat | covered the outer periphery of the said insulation coating conducting wire with low melting-point resin.

Next, a preferred embodiment of the resin sheath 18 is as follows. That is, as the resin sheath 18, the core 13 around which the coil conductor 17 including the tapered portion TP of the upper flange 15 is wound and the one main surface 11 a side of the substrate 11 are covered with the resin sheath 18. Preferably it is. The resin sheath 18 is a one-component thermosetting resin in view of workability, and is preferably a liquid at room temperature, and an epoxy resin system is preferable. The resin sheath 18 may contain magnetic powder and other fillers. Various magnetic powders can be used as the magnetic powder. Specifically, one or more selected from Ni—Zn ferrite powder, Ni—Zn—Cu ferrite powder, Mn—Zn ferrite powder, metal magnetic powder, and the like are mixed. Are preferably used. The particle size of the magnetic powder is preferably 5 to 20 μm. Moreover, as for content of the said magnetic powder in the said magnetic powder containing resin 16, 30-80 wt% is preferable.

Next, a first embodiment of the method for manufacturing the surface-mounted coil component of the present invention will be described with reference to FIGS. FIG. 2 is a cross-sectional view showing the main part of the first half process of an example of the method for manufacturing the surface-mounted coil component of the present embodiment. FIG. 3 is a cross-sectional view showing the main part of the latter half of the process for producing the surface-mounted coil component according to this embodiment.

In the method of manufacturing the surface mount type coil component according to this embodiment, first, the upper surface of the upper flange 15 having the winding core portion 14 and a pair of flanges 15 and 16 provided above and below the winding core portion 14. 15a includes a step of preparing a plurality of cores 13 and 13 having tapered portions TP formed toward the outer periphery of the flange 15. Specifically, for example, as shown in FIG. 2A, a substantially prismatic green sintered body 13 ″ having a tapered portion TP ′ provided on the upper surface side is prepared. Next, FIG. As shown, the side surface of the molded body 13 ″ is ground by centerless polishing or the like to obtain a drum-shaped molded body 13 ′ having a winding core portion 14 ′, an upper flange 15 ′, and a lower flange 16 ′. Next, after removing the binder 13 ′ from the binder, the molded body 13 ′ was fired at a predetermined temperature, and provided on the core portion 14 and above and below the core portion 14 as shown in FIG. A plurality of cores 13 and 13 having a pair of flanges 15 and 16 and having a tapered portion TP formed on the upper surface 15a of the upper flange 15 toward the outer periphery of the flange 15 are obtained. Next, the method of manufacturing the surface mount type coil component according to the present embodiment uses a plurality of cores 13 and 13 obtained as described above, and a plurality of terminal electrodes as shown in FIGS. A step of mounting the plurality of cores 13 and 13 such that the lower surface 16b of the lower flange 16 is in contact with one main surface 11a of the collective substrate 11A that can take a large number of substrates 11 having 12a and 12a. Have. Specifically, for example, as shown in FIG. 3D, first, the substrate is formed at a predetermined position of an aggregate substrate 11A from which a large number of substrates 11 can be taken, extending from one main surface 11a to the other main surface 11b. A through hole TH that penetrates 11A in the thickness direction is provided. Next, as shown in FIG. 3E, a plurality of connection electrodes 12a and 12a are provided on one main surface 11a side of the collective substrate 11A, and through-hole conductors 12c filled in the through-holes TH. A plurality of terminal electrodes 12b and 12b are formed on the other main surface 11b side of the collective substrate 11A so as to be connected to the connection conductor 12a. Next, as shown in FIG. 3F, the plurality of cores 13 and 13 are mounted so that the lower surface 16b of the lower flange 16 is in contact with one main surface 11a of the collective substrate 11A. Next, as shown in FIG. 3G, the coil conductor 17 is sequentially wound around the cores 13 and 13 on the collective substrate 11A, and the end portions 17a and 17b of the coil conductor 17 are connected to the terminals of the substrate 11. It has the process of connecting to the connection electrode 12a connected to the electrode 12b by thermocompression bonding, respectively. Next, as shown in FIG. 3 (H), vacuum printing is performed so as to cover the plurality of cores 13 around which the coil conductor 17 including the tapered portion TP is wound and the one main surface 11a side of the collective substrate 11A. A resin coating 18 is formed by applying a resin by a method. Next, there is a step of obtaining the plurality of surface mount type coil components 10 and 10 by dividing the collective substrate 11A on which the resin sheath 18 is formed by dicing. Specifically, the collective substrate 11A on which the resin sheath 18 is formed is divided by dicing along the cut line CL as shown in FIG. 3H, and a plurality of pieces are obtained as shown in FIG. The surface mount type coil components 10 are obtained. For example, the cut line CL may be set based on the connection electrode formed on the other main surface of the collective substrate, but is not limited thereto.

A taper portion TP is formed on the upper surface 15a of the upper flange 15 toward the outer periphery of the flange 15 and includes the core section 14 and a pair of flanges 15 and 16 provided above and below the core section 14. A preferred embodiment of the step of preparing the plurality of cores 13 is as follows. That is, as the step of preparing the plurality of cores 13, for example, as shown in FIG. 2A, first, Ni—Zn—Cu ferrite is used as the magnetic material, and the magnetic material powder and binder are used. Are mixed and granulated, and then formed into a substantially prismatic shaped body 13 ″ using a powder molding press provided with a reverse taper portion of a predetermined angle −θ toward the outer periphery of one pressing surface of the mold. Next, a recess is formed by centerless polishing to obtain a drum-shaped molded body 13 'as shown in Fig. 2 (B). It is preferable to obtain a drum-shaped core 13 as shown in FIG. 2C by performing a binder removal process at around 800 ° C. and then firing at a predetermined temperature according to the sintering temperature of the magnetic material. The step of preparing the plurality of cores is as described above. For example, Ni—Zn—Cu based ferrite is used as the magnetic material, and the magnetic material powder and a binder are mixed and granulated, and then a prismatic shaped product using a powder molding press. Next, a concave portion is formed by centerless polishing to obtain a drum-shaped molded body, and the drum-shaped molded body thus obtained is debindered at around 800 ° C. A drum shape in which the upper ridge is provided in a shade shape with respect to the core portion by firing at a predetermined temperature in accordance with the sintering temperature of the magnetic material with a heat-resistant weight placed thereon You may obtain the core of.

Next, the plurality of cores are arranged such that the lower surface 16b of the lower flange 16 is in contact with one main surface 11a of the collective substrate 11A that can take a large number of substrates 11 having the plurality of terminal electrodes 12a, 12a. A preferred embodiment of the process of mounting 13, 13 is as follows. That is, in the step of mounting the plurality of cores, the upper surface 15a of the upper flange 15 on the extension of the center line of the core 14 of the core 13 is sucked by a suction nozzle (not shown) to hold the core 13. Then, after applying an adhesive or the like in advance to at least one of the lower surface 16b of the flange 16 below the core 13 or one main surface 11a of the collective substrate 11A, the core 13 is mounted and the lower side of the core 13 is mounted. It is preferable that the lower surface 16b of the flange 16 is fixed on one main surface 11a of the collective substrate 11A. At this time, it is preferable that the tapered portion TP of the upper surface 15a of the flange 15 above the core 13 is partially formed toward the outer periphery of the flange 15, and according to this, the suction by the suction nozzle is performed. Can be done accurately.

Next, the coil conductor 17 is sequentially wound around the cores 13 on the collective substrate 11A, and the end portions 17a and 17b of the coil conductor 17 are connected to the connection electrode 12a connected to the terminal electrode 12b of the substrate 11. A preferred embodiment of the step of connecting by thermocompression bonding is as follows. That is, as the winding and connecting step, for example, the nozzle N of the winding machine is controlled according to a program, and the coil conductors 17 are sequentially wound around the core portions 14 of the plurality of cores 13. The end portions 17a and 17b are preferably connected to the connection electrode 12a on the one main surface 11a side of the collective substrate 11A by thermocompression bonding. The operation of winding the coil conductor 17 around the plurality of cores 13 and 13 and the operation of connecting the end portions 17a and 17b of the coil conductor 17 to the connection electrode 12a are preferably performed sequentially in parallel. After completing only the former work, the latter work may be performed, or the former work and the latter work may be performed alternately.

Next, a resin is applied by a vacuum printing method so as to cover the plurality of cores 13 around which the coil conductors 17 including the tapered portion TP are wound and the one main surface 11a side of the collective substrate 11A, and then the resin sheath 18A. A preferred embodiment of the step of forming is as follows. That is, as the step of forming the resin sheath 18, the collective substrate 11A obtained above is set in a screen printing apparatus installed in a vacuum chamber (not shown). For example, 50 wt% of epoxy resin as resin and Ni as filler -A resin solution in which 50 wt% of Zn-Cu ferrite powder and 5 wt% of solvent naphtha as a solvent are mixed is applied by screen printing, and the inside of the vacuum chamber is depressurized to eliminate bubbles from the resin, and then at 100 ° C. It is preferable that the resin sheathing 18 is formed by drying for 30 minutes and holding at 150 ° C. for 1 hour to cure the resin. At this time, in the core 13, the tapered portion TP is partially formed toward the outer periphery of the flange 15 above the core 13, so that it is on the extension of the center line of the core portion 13 of the core 13. A flat surface remains in the vicinity of the center of the upper surface 15a of the upper flange 15, and the flat surface of the remaining portion receives the pressure applied by the squeegee through the printing screen, and the printing screen is damaged. It can be avoided.

Next, a preferred embodiment of the process of obtaining the plurality of surface mount coil components 10 and 10 by dividing the collective substrate 11A on which the resin sheath 18A is formed by dicing is as follows. That is, as the step of dividing the plurality of surface mount type coil components 10, 10, a rotating disk-shaped grinding blade (not shown) is brought into contact with the collective substrate 11A on which the resin sheath 18A is formed, and the resin sheath It is preferable to form a cut groove so as to reach at least a part of the thickness dimension of the collective substrate 11A from the 18A side, and then divide the remainder of the thickness dimension of the collective substrate 11A by means such as bending or pressing. For example, a dicing auxiliary adhesive sheet (not shown) is attached to the lower surface of the collective substrate 11A, and all the thickness dimensions of the collective substrate are left, leaving a part of the thickness of the auxiliary adhesive sheet. The auxiliary pressure-sensitive adhesive sheet can also be peeled and removed after forming a kerf extending over.

(Example 1) Next, an example of the surface mount type coil component 10 according to the first embodiment of the present invention will be described. First, Ni—Zn—Cu ferrite powder is used as a magnetic material, and PVA (polyvinyl alcohol) is mixed as an organic binder for powder molding and granulated, and then one of molds is granulated. Using a powder molding press provided with a reverse taper portion having a predetermined angle −θ toward the outer periphery near the outer periphery of the pressing surface, a substantially prismatic shaped body 13 ″ having a tapered portion TP ′ having an angle θ on the upper surface is prepared. Then, the peripheral side surface of the molded body 13 ″ is ground by centerless polishing using a grinding wheel (not shown), and as shown in FIG. 2 (B), the core portion 14 ′ and the upper and lower portions of the core portion 14 ′. A drum-shaped molded body 13 ′ having a pair of flanges 15 ′ and 16 ′ provided on the upper surface 15a ′ of the upper flange 15 ′ and a tapered portion TP ′ formed toward the outer periphery of the flange 15 ′. Got. Next, the drum-shaped molded body 13 ′ was subjected to binder removal treatment at 600 ° C. for 60 minutes, and then fired at 1050 ° C. for 2 hours. The outer shape of the upper ridge 15 and the lower ridge 16 was 2.5 mm square, The height including the thicknesses of the flanges 15 and 16 is 0.8 mm, the radius of the core 14 is 0.4 mm, and the inner peripheral side of the tapered portion TP is a square having a radius of 0.5 mm from the center of the upper flange 15. A drum-shaped core 13 was obtained. Next, as shown in FIG. 3D, there is prepared an aggregate substrate 11A made of alumina having a thickness of 0.2 mm capable of taking a large number of substrates 11 provided with through holes TH penetrating in the thickness direction at predetermined positions. As shown in FIG. 3E, one main surface 11a side of the aggregate substrate 11A is formed by screen printing using an electrode material paste containing Cu powder and glass frit as binder and ethyl cellulose and terpineol as organic solvent. A plurality of connection electrodes 12a, 12a and a plurality of connection electrodes 12a on the other main surface 11b side of the collective substrate 11A so as to be connected to the connection conductor 12a via a through-hole conductor 12c filled in the through-hole TH. The terminal electrodes 12b and 12b were sequentially applied and formed, dried at 100 ° C. for 15 minutes, and then baked at 800 ° C. for 120 minutes in an N ₂ gas atmosphere. . Next, as shown in FIG. 3 (F), after applying an epoxy-based adhesive to one main surface 11a of the collective substrate 11A, the central portion of the upper surface 15a of the flange 15 above the core 13 is formed. The plurality of cores 13 and 13 are mounted so that the lower surface 16b of the lower flange 16 is in contact with one main surface 11a of the collective substrate 11A. Next, as shown in FIG. 3 (G), the nozzle N of the winding machine is controlled according to the program, and the coil conductors 17 made of polyurethane-coated copper wire having a diameter of 80 μmΦ are respectively provided on the cores 13 and 13 on the collective substrate 11A. The ends 17a and 17b of the coil conductor 17 were joined to the connection electrode 12a connected to the terminal electrode 12b of the substrate 11 by thermocompression bonding using a heater chip (not shown). Next, the aggregate substrate 11A obtained above is set in a screen printing apparatus installed in a vacuum chamber (not shown), epoxy resin is 50 wt% as a resin, Ni-Zn-Cu ferrite powder is 50 wt% as a filler, A resin solution in which 5 wt% of solvent naphtha was mixed as a solvent was applied by screen printing, the inside of the vacuum chamber was reduced to 0.1 MPa to eliminate bubbles from the resin, dried at 100 ° C. for 30 minutes, and 150 ° C. 1 hour to cure the resin, and as shown in FIG. 3 (H), one of the plurality of cores 13 around which the coil conductor 17 including the tapered portion TP is wound and one of the aggregate substrates 11A A resin sheath 18A was formed so as to cover the surface 11a side. Next, an auxiliary adhesive sheet for dicing (not shown) is attached to the lower surface of the collective substrate 11A, and a kerf over the entire thickness dimension of the collective substrate 11A is left, leaving a part of the thickness dimension of the auxiliary adhesive sheet. After the formation, the auxiliary pressure-sensitive adhesive sheet was peeled and removed to obtain a plurality of surface mount type coil components 10 and 10 as shown in FIG. The obtained surface mount type coil components 10, 10 were subjected to cross section polishing so that a center line passing through the core portion perpendicularly was exposed, and the obtained cross section was confirmed with a microscope. As a result, the length from the upper surface of the upper heel to the upper surface of the substrate in the vicinity of the outer peripheral edge of the upper heel is larger than the length from the upper surface of the upper heel to the upper surface of the substrate in the vicinity of the core portion. Was confirmed to be short. In performing the cross-sectional polishing, it is preferable to perform the cross-sectional polishing in a state where the surface mount coil component 10 is embedded in an embedded resin or the like so that the handling is easy.

Next, a second embodiment of the surface mount type coil component of the present invention will be described with reference to FIG. FIG. 4 is a longitudinal sectional view showing the entire structure of the surface mount type coil component 20 of the present embodiment.

As shown in FIG. 4, the surface mount type coil component 20 of the present embodiment includes a substrate 21, a drum-shaped core 23, a coil conductor 27 wound around the core 23, and a resin sheath 28 that covers the core 23. It is what has. Specifically, a substrate 21 having a plurality of connection electrodes 22a on one main surface 21a and a plurality of terminal electrodes 22b connected to the connection electrodes 22a on the other main surface 21b, a core portion 24, A core 23 having a pair of flanges 25 and 26 provided above and below the core 24 and having a lower surface 26b of the lower flange 26 fixed to one main surface 21a of the substrate 21; 23 is a surface mount type coil component 20 having a coil conductor 27 wound around the winding core portion 24 and having end portions 27a and 27b connected to the connection electrodes 22a and 22a of the substrate 21, respectively. A taper portion TP is formed on the upper surface 25a of the flange 25 above the core 23 toward the outer periphery of the flange 25, and the core 23 and the coil conductor 27 including the taper portion TP are wound thereon. It is covered by the one main surface 21a side resin sheathing 28 of the substrate 21.

Further, in the surface mount type coil component 20 of the present embodiment, the tapered portion TP is formed in part toward the outer periphery of the flange 15 above the core 23.

Further, in the surface mount type coil component 20 according to the present embodiment, unlike the first embodiment, the core 23 has the upper flange 25 formed in a shade shape with respect to the core portion 24.

A preferred embodiment of the shade-like upper ridge 25 is as follows. That is, the cap-shaped upper collar 25 is formed such that the distance from the upper surface 26a of the lower collar 26 opposed to the outer core 25 decreases as the distance from the upper end of the core portion 24 toward the outer periphery decreases. It is preferable. According to this, while having the taper portion TP on the upper surface 25a side of the upper flange 25, the height dimension of the core 23 can be kept to the minimum necessary for obtaining predetermined magnetic characteristics of the coil. As a result, a thin surface-mounted coil component can be provided. Other configurations and operational effects are the same as in the first embodiment, and a description thereof will be omitted.

Next, a second embodiment of the method of manufacturing the surface mount type coil component of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing a partial process of an example of the method for manufacturing the surface-mounted coil component of the present embodiment.

In the method of manufacturing the surface mount type coil component according to this embodiment, first, the upper surface of the upper flange 25 having the winding core portion 24 and a pair of flanges 25 and 26 provided above and below the winding core portion 24. 25a includes a step of preparing a plurality of cores 23 and 23 having tapered portions TP formed toward the outer periphery of the flange 25. Specifically, for example, as shown in FIG. 5 (J), Ni—Zn—Cu ferrite is used as the magnetic material, the magnetic material powder and a binder are mixed, granulated, and then powder molded. Using a press, a prismatic shaped body 23 ″ is formed. Next, a recess is formed by centerless polishing to obtain a drum shaped shaped body 23 ′ as shown in FIG. 5 (K). The obtained drum-shaped molded body 23 ′ was debindered at around 800 ° C., and then the magnetic material with the heat-resistant weight WT placed on the upper bowl 25 ′ as shown in FIG. 5 (L). By firing at a predetermined temperature according to the sintering temperature of the material, as shown in FIG. 5 (M), a drum-shaped core 23 in which the upper flange 25 is provided in a shade shape with respect to the core portion 24. Since the subsequent steps are the same as those in the first embodiment, description thereof is omitted. To.

(Example 2) Next, an example of the surface mount type coil component 20 according to the second embodiment of the present invention will be described. First, Ni—Zn—Cu ferrite powder is used as the magnetic material, and the powder of the magnetic material is mixed with PVA as the organic binder for powder molding. After granulating, the prismatic shape is formed using a powder molding press. Then, the molded body 23 ″ was formed. Next, the peripheral side surface of the molded body 23 ″ was ground by centerless polishing to form a recess, and as shown in FIG. 5 (K), the core portion 24 ′ and the core A drum-shaped molded body 23 ′ having a pair of flanges 25 ′ and 26 ′ provided above and below the portion 24 ′ was obtained. Next, after the obtained drum-shaped molded body 23 ′ was subjected to binder removal treatment at around 600 ° C. for 60 minutes, as shown in FIG. 5 (L), the outer periphery was within a radius of 2.5 mm on the upper flange 25 ′. Firing is carried out at 1050 ° C. for 2 hours with an alumina heat-resistant ring-shaped weight WT made of alumina having a radius of 1.0 mm and a height of 5 mm, and the outer shape of the upper ridge 25 and the lower ridge 26 is 2. 5 mm square, height dimension including the thickness of the flanges 25 and 26 is 0.8 mm, the radius of the core part 24 is 0.4 mm, and the inner periphery of the taper part TP is 0. 0 radius from the center of the upper flange 25. 5 mm, and provided with a shade-like upper flange 25 formed so that the distance from the upper surface 26a of the lower flange 26 facing each other decreases as the distance from the upper end of the core portion 24 toward the outer periphery decreases. A square drum-shaped core 23 was obtained. The following steps were performed in the same manner as in the first embodiment to obtain a plurality of surface mount type coil components 20, 20 as shown in FIG.

In addition, in the principal part sectional drawing of each said embodiment, although the coil conductor was abbreviate | omitted and described, while the outer periphery of the wound coil conductor has some unevenness | corrugations, a small clearance gap remains between each conductor, respectively. is doing. For this reason, in the first and second embodiments, the resin sheath is also interposed in a slight gap between the wound coil conductors. Absent.

The present invention is suitable for surface mount type coil components used in various portable and thin electronic devices.

It is a longitudinal cross-sectional view which shows 1st Embodiment of the coil components of this invention. It is sectional drawing which shows the principal part of the first half of the process of 1st Embodiment of the manufacturing method of the coil components of this invention. It is sectional drawing which shows the principal part of the second half of the process of 1st Embodiment of the manufacturing method of the coil components of this invention. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the coil components of this invention. It is sectional drawing which shows the principal part of the first half of the process of 2nd Embodiment of the manufacturing method of the coil components of this invention. It is a longitudinal cross-sectional view which shows an example of background art. It is a longitudinal cross-sectional view which shows the other example of background art.

Explanation of symbols

10: surface mount type coil component 11: substrate 11A: collective substrate 11a: one main surface 11b: the other main surface 12a: connection electrode 12b: terminal electrode 12c: through-hole conductor 13: cores 13 ′, 13 ″: molded body 14: Winding core portion 15: Upper flange 15a: Upper surface 15b: Lower surface 16: Lower flange 16a: Upper surface 16b: Lower surface 17: Coil conductors 17a, 17b: End portion 18: Resin sheath 18A: Resin sheath 20: Surface mount type Coil component 21: Substrate 21A: Collective substrate 21a: One main surface 21b: The other main surface 22a: Connection electrode 22b: Terminal electrode 22c: Through-hole conductor 23: Core 23 ′, 23 ″: Molded body 24: Core portion 25: Upper flange 25a: Upper surface 25b: Lower surface 26: Lower flange 26a: Upper surface 26b: Lower surface 27: Coil conductors 27a, 27b: End portion 28: Resin sheath CL: Cut line N: Winding Zur TP: the tapered portion WT: weigh

Claims (4)

A substrate having a plurality of connection electrodes on one main surface and a plurality of terminal electrodes respectively connected to the connection electrodes on the other main surface, and a pair of cores provided above and below the cores And a core having a lower surface of the lower collar fixed to one main surface of the substrate, and an end portion of the core wound around the core portion of the core and a connection electrode of the substrate. And a coil conductor connected to the upper surface of the flange above the core, wherein a tapered portion is formed toward the outer periphery of the flange, and the coil conductor including the tapered portion is A surface-mounting coil component, wherein a wound core and one main surface side of the substrate are covered with a resin sheath. The surface mount type coil component according to claim 1, wherein the tapered portion is formed in a part toward an outer periphery of the ridge above the core. The surface mount type coil component according to claim 1, wherein the core has the upper collar formed in a shade shape with respect to the core portion. Preparing a plurality of cores having a winding core portion and a pair of ridges provided above and below the winding core portion and having a tapered portion formed on the upper surface of the upper ridge toward the outer periphery of the ridge; Mounting the plurality of cores such that the lower surface of the lower ridge is in contact with one main surface of the collective substrate capable of taking a large number of substrates having a plurality of terminal electrodes; and on the collective substrate A coil conductor is sequentially wound around the core, and an end of the coil conductor is connected to a connection electrode connected to the terminal electrode of the substrate by thermocompression bonding, and the coil conductor including the tapered portion is wound. A step of applying a resin by a vacuum printing method so as to cover a plurality of rotated cores and one main surface side of the collective substrate to form a resin sheath, and a collective substrate on which the resin sheath is formed is divided by dicing. Multiple surface mounting Method for manufacturing a surface mount type coil component and having a step of obtaining a coil component, a.

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