JP2007180400A - Surface-mounting type electronic component and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounting type electronic component that can be sucked and held satisfactorily by a suction nozzle for sucking by suction force, even if the surface-mounting type electronic component is particularly compact and light, and to provide a method of manufacturing the surface-mounting type electronic component. <P>SOLUTION: A coil chip part 2 comprises a core section 4, having a pair of rectangular flanges at both the axial ends of a core-winding section 4a; a wire 10a wound around the core-winding section 4a; a flange-covering section 30a for covering break sections 10b, 10c in the wire positioned at the outer periphery of the flange halfway; a packaging resin section 30, that is formed integrally with the flange covering section 30a, covers the periphery of the wire 10a wound around the core-winding section 4a, and has a flat surface 30b at least on one surface; and a pair of edge electrodes 40, formed to directly cover the outer-periphery surface of the flange from the end face of the flanges 4b, 4c to make connection to the wire break sections 10b, 10c and to cover the flange covering section 30a in the packaging resin section 30. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a surface-mounted electronic component and a method for manufacturing the same, and more particularly, even a small and light-weight surface-mounted electronic component can be satisfactorily sucked and held by a suction nozzle that sucks with a suction force. The present invention relates to a surface mount electronic component and a manufacturing method thereof.

  As an example of a surface mount electronic component, for example, a wound electronic component disclosed in Patent Document 1 below is known.

  In this wound electronic component, the outer peripheral surface of the exterior resin portion formed on the outer periphery of the core portion of the ferrite core is polished so as not to protrude from the outer periphery of the end electrode. In paragraph No. 0011 of Patent Document 1, it is described that the outer peripheral surface of the exterior resin portion can be polished to satisfactorily adsorb electronic components and improve the stability on the substrate.

  However, in the wound electronic component shown in Patent Document 1, the exterior resin portion covers only the outer periphery of the coil portion, and does not cover the outer periphery of the flange-shaped flanges formed at both ends of the core portion. For this reason, it has the subject that foreign substances, such as a water | moisture content, enter easily from the clearance gap between an exterior resin part and the flange of a core part.

  Therefore, as shown in FIG. 13B of Patent Document 2 below, not only the outer periphery of the coil part but also the outer periphery of the part including the outer periphery of the flanges formed at both ends of the core part is packaged. A structure covering with a resin portion has also been proposed.

However, in the structure of the wound electronic component shown in Patent Document 2, in order to cover the entire periphery of the component, including the outer periphery of the flange formed at both ends of the core portion, with the exterior resin portion, Connection with the connecting line tends to be insufficient. In addition, the bonding strength between the end electrode and the exterior resin part is likely to be lowered.
JP 10-163033 A Japanese Patent Laid-Open No. 10-172853

  The present invention has been made in view of such a situation, and the object of the present invention is to be able to satisfactorily suck and hold even a small and light-weight surface-mounted electronic component by a suction nozzle that sucks by suction force, The gap between the outer resin part and the flange of the core part is sealed well, the connection between the end electrode and the coil connecting part is sufficiently secured, and the bonding strength between the end electrode and the outer resin part is high. A surface-mount type electronic component and a manufacturing method thereof are provided.

In order to achieve the above object, a surface mount electronic component according to the present invention is
A core portion having a pair of square flanges at both axial ends of the core portion;
A wire wound around the core portion;
A resin flange covering portion covering the connecting portion of the wire located on the outer periphery of each flange halfway;
An exterior resin portion formed integrally with the flange covering portion, covering the periphery of the wire wound around the core portion, and having a flat surface on at least one surface;
A pair of end electrodes formed so as to directly cover the outer peripheral surface of the flange from the end surface of the flange and to cover the flange covering portion of the exterior resin portion so as to be connected to the connecting portion of the wire Have
The flat surface of the exterior resin part is an adsorption surface.

  In the surface-mounted electronic component according to the present invention, the resin flange covering portion that is a part of the exterior resin portion covers the wire connecting portion located on the outer periphery of the flange partway. The end electrode directly covers the outer peripheral surface of the flange from the end surface of the flange so as to be connected to the wire connecting portion, and also covers the flange covering portion of the exterior resin portion. For this reason, the gap between the outer resin portion and the flange of the core portion is well sealed, and the connection between the end electrode and the wire connecting portion is sufficiently secured, so that the end electrode and the outer resin portion High bonding strength.

  Moreover, in the surface mount type electronic component of the present invention, the flat surface of the exterior resin part not covered by the end electrodes becomes the suction surface, and even a small and light surface mount type electronic component is sucked by suction force. Adsorption can be satisfactorily held by the adsorption nozzle.

  Preferably, the axial length of the flat portion of the exterior resin portion not covered with the end electrode is 30 to 70% of the total length of the electronic component. The flat part of the exterior resin having such an axial length can be satisfactorily held by suction by the suction nozzle.

  Preferably, the end electrode has a thickness of 8 μm or less. The end electrode having such a thickness is formed by a plating method or the like. Because the end electrode is thin in this way, even if the end of the suction nozzle is positioned on the end electrode, the suction action is not reduced so much by the suction nozzle, and the part can be held with sufficient suction force. Can do.

  Preferably, a stepped recess that is continuous in the circumferential direction is formed on the outer peripheral surface of each end electrode. By forming the stepped recesses, the stepped shape formed on the bottom surface of the end electrodes formed at both ends of the electronic component during solder reflow, especially when mounting small and lightweight surface mount type electronic components Solder enters the recess. Since the step-like recesses are formed continuously in the circumferential direction of the end electrodes, a sufficient amount of solder can be secured. As a result, the so-called tombstone phenomenon can be effectively prevented and mounting defects can be prevented.

A method for manufacturing a surface-mounted electronic component according to the present invention includes:
Preparing a core portion having a pair of square flanges at both axial ends of the core portion;
Forming a coil part by winding a wire around the core part; and
Forming a connecting portion of the wire on the outer periphery of the flange;
The core portion around which the wire is wound is arranged in the mold in at least one line in the axial direction, and the end surfaces of the flanges in the adjacent core portions are in contact with each other, and on the flange outer periphery of the end surface where these flanges contact. Forming a cavity on the outer periphery of the coil part and the outer periphery of the flange part by contacting the holding convex part of the mold; and
Resin is injected into the cavity, and a resin flange covering portion covering the connecting portion of the wire located on the outer periphery of each flange to the middle, and the flange covering portion are formed integrally, covering the periphery of the coil portion And a step of molding an exterior resin portion having a flat surface on at least one surface thereof.

  In the method of the present invention, it is only necessary to devise the shape of the mold, and it is not necessary to process the core part itself. Therefore, the volume of the core portion does not decrease and the performance as an electronic component is not affected at all. In addition, the resin flange covering part, which is a part of the exterior resin part, is formed with a single resin molding, and many resin molded products have a structure that covers the wire connecting part located on the outer periphery of the flange partway. Can be manufactured.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a longitudinal sectional view of a coil chip component as a surface mount electronic component according to an embodiment of the present invention,
2 is a cross-sectional view of a main part of a mold showing an example of a manufacturing process of the coil chip component shown in FIG.
3 is a cross-sectional view of the main part of the coil chip component shown in FIG.
FIG. 4 is a schematic perspective view showing a state where the coil chip component shown in FIG. 1 is sucked by a suction nozzle.

  As shown in FIG. 1, a coil chip component 2 as a surface mount electronic component according to an embodiment of the present invention has a drum core 4 as a core portion (core material). The drum core 4 is made of a ferrite material. The drum core 4 has a core part 4 a in which a wire 10 a constituting the coil part 10 is wound along the axial direction of the core 4.

  A first flange 4b and a second flange 4c are integrally formed at the first end and the second end, which are both ends in the axial direction of the core 4a. The outer dimensions of the first flange 4b and the second flange 4c are larger than the outer diameter of the core 4a.

  The cross section of the core part 4a is not particularly limited, and may be a rectangular cross section, a circular cross section, or other cross sectional shapes. The cross-sectional shape of the first flange 4b and the second flange 4c is a square shape such as a rectangular cross section. The 1st flange 4b and the 2nd flange 4c are the same size, for example, length is about 0.82 mm and width is about 0.30 mm. Moreover, the outer diameter of the core part 4a is about 0.42 mm. The total axial length L0 of the drum core 4 (substantially the same as the total length of the component 2) L0 is about 1.637 mm.

  As shown in FIG. 1, the connecting portions 10b and 10c formed at both ends of the wire 10a constituting the coil portion 10 are connected to the base electrode layer 20 at the outer peripheral positions of the flanges 4b and 4c. The connecting portions 10b and 10c of the wire 10a are fixed to the outer circumferences of the flanges 4b and 4c by means such as thermocompression bonding after the base electrode layer 20 is formed, and these connecting connections are ensured.

  The base electrode layer 20 is an electroless Ni plating having a first layer of 1.0 to 2.0 μm and a second layer of electrolytic Ni plating having a thickness of 1.0 to 2.0 μm.

  After the base electrode layer 20 and the connecting portions 10b and 10c are connected, the outer resin portion 30 is formed by molding a resin in the outer circumferential concave portion of the core portion 4a where the coil portion 10 is formed. It does not specifically limit as resin which comprises the exterior resin part 30, An epoxy resin, a phenol resin, a diallyl phthalate resin, a polyester resin etc. are illustrated.

  The exterior resin part 30 is molded using, for example, molds 80 and 82 shown in FIG. As shown in FIG. 2, the connected drum core 4 in which the coil portion 10 is formed inside the plurality of cavities 84 formed by closing the molds 80 and 82 is connected to the first drum core 4 of the adjacent drum core 4. It arrange | positions along with an axial direction so that the end surface of the flange 4b may contact the end surface of the 2nd flange of the adjacent drum core 4. FIG.

  The molds 80 and 82 are formed with holding convex portions 86 for holding the outer periphery of the contact portion between the first flange 4b and the second flange 4c of the drum core 4 disposed adjacent to each other. A circumferential gap 88 for forming the resin flange covering portion 30a shown in FIG. The circumferential gap 88 communicates with the cavity 84, and resin is injected into the cavity 84 and molded, and the molds 80 and 82 are opened, so that the exterior resin part 30 having the flange covering part 30a shown in FIG. A plurality of integrated element bodies 5 are obtained. The four side surfaces of the exterior resin part 30 are flat surfaces.

  The outer diameter of the exterior resin portion 30 of each element body 5 is larger than the outer dimensions (the maximum outer dimensions of the core portion) of the first flange 4b and the second flange 4c, and the first flange 4b and the second flange 4c. A flange covering portion 30a having a predetermined thickness is formed on the outer periphery. The flange covering portion 30a is formed integrally with the exterior resin portion 30, and is formed so as to cover the outer periphery of the flange portions 4b and 4c from the inner side to the outer side to the middle position in the axial direction.

  The thickness of the flange covering portion 30a corresponds to the depth H1 of the step-shaped recess 50 described later. Further, the axial length of the flange covering portion 30a is determined so as to appropriately adjust the axial width (W1) of the step-shaped recess 50 described later.

  After the exterior resin portion 30 is formed, the coil chip component 2 is obtained by forming a pair of end electrodes 40 at both axial ends of the element body 5. The end electrode 40 is formed after the exterior resin part 30 is formed.

  In this embodiment, each end electrode 40 has electroless Ni plating of 1.0 to 2.0 μm for the first layer, electrolytic Ni plating of 1.0 to 2.0 μm for the second layer, and 3 for the third layer. Electrolytic Sn plating of 0.0 to 4.0 μm. The thickness t1 of the end electrode 40 is 8 μm or less.

  Each end electrode 40 is formed in a stepped shape so as to directly cover the outer peripheral surface of the flange 4b, 4c from the end face of each flange 4b, 4c and to cover the flange covering portion 30a of the exterior resin portion 30. . Each end electrode 40 is directly connected to the base electrode layer 20 and the connecting portions 10b and 10c at the end surfaces of the flanges 4b and 4c and a part of the outer peripheral surface of the flanges 4b and 4c. Moreover, since each end electrode 40 is formed so as to cover the flange covering portion 30a of the exterior resin portion 30, a step-like recess 50 that is continuous in the circumferential direction is formed on the outer peripheral surface of each end portion 40. Is done.

  As shown in FIG. 1, the step-shaped recess 50 is formed with a predetermined width (W1) from the axial end surface of the element body 5, and the ratio (W1 / W0) to the total width (W0) of each end electrode. ) Is preferably 0.1 to 0.8, more preferably 0.3 to 0.6. By setting the ratio (W1 / W0) within the above range, the connection between the end electrode 40 and the coil connecting portions 10b and 10c is sufficiently secured, and the bonding strength between the end electrode 40 and the exterior resin portion 30 is also high. high. Moreover, the effect which suppresses a tombstone phenomenon is large by setting it as this range.

  The tombstone phenomenon means that when an electronic component is mounted on a substrate, the electronic component starts up due to an imbalance of moments generated on the solder paste surfaces of the end electrodes formed at both ends of the electronic component. This is a phenomenon that results in poor bonding.

  Further, the stepped recess 50 is formed such that the depth (H1) from the maximum outer peripheral surface dimension of each end electrode 40 is 10 to 40 μm. By setting the depth H1 within this range, the connection between the end electrode 40 and the coil connection portions 10b and 10c is sufficiently secured, and the bonding strength between the end electrode 40 and the exterior resin portion 30 is also high. Moreover, the effect which suppresses a tombstone phenomenon is large by setting it as this range. On the other hand, if the depth H1 is too deep, the maximum outer dimensions of the flange portions 4b and 4c in the drum core 4 are relatively small with a limited chip size, and the electrical performance tends to deteriorate. .

  The ratio (H1 / H0) of the depth (H1) of the stepped recess 50 to the total height (H0) of the maximum outer peripheral surface of each end electrode 40 is in the range of 0.011 to 0.045. By setting the ratio within this range, the connection between the end electrode 40 and the coil connecting portions 10b and 10c is sufficiently secured, and the bonding strength between the end electrode 40 and the exterior resin portion 30 is also high. Moreover, the effect which suppresses a tombstone phenomenon is large by setting it as this range.

  In the present embodiment, in particular, even when the chip maximum height H0 is 0.9 mm or less and the coil tip part 2 is 5 mg or less in light weight, during solder reflow during mounting, as shown in FIG. In addition, the solder 70 enters the gap between the stepped recess 50 formed on the bottom surface of the end electrode 40 and the substrate 60. Since the step-shaped recess 50 is formed continuously in the circumferential direction of the end electrode 40, the amount of wraparound of the solder 70 can be sufficiently secured. As a result, the so-called tombstone phenomenon can be effectively prevented and mounting defects can be prevented. For example, in the conventional coil chip component (there is no stepped recess 50), the tombstone phenomenon occurred at a ratio of about 10 per 100,000, whereas the embodiment of the present invention (the stepped recess 50) In some cases, no tombstone phenomenon occurred.

  Further, in this embodiment, the solder 70 wraps around the stepped recess 50, so that sufficient bonding strength can be obtained even if the size of the fillet formed by the solder 70 is reduced, and high-density mounting is possible. .

  In the present embodiment, the stepped recess 50 is formed by forming the end electrode 40 so as to cover the outer periphery of both ends of the exterior resin part 30 having an outer dimension larger than the maximum outer dimension of the flanges 4b and 4c. It is formed. For this reason, it is not necessary to process the flange itself, the volume of the flange does not decrease, and the performance as a coil chip is not affected at all. Moreover, since the stepped recess 50 can be formed by resin molding, the manufacturing process is not complicated.

  Furthermore, in this embodiment, the axial width W0 of each end electrode 40 shown in FIG. 1 is preferably 0.41 mm, so that the flat surface of the exterior resin portion 30 located between the edges of the end electrode 40 is provided. The axial width L1 of 30b can be about 0.817 mm. The axial width L1 of the flat surface 30b is 30 to 70% of the total length L0 of the component 2.

  The upper flat portion 30b of the exterior resin portion 30 having such an axial length L1 can be favorably held by the suction nozzle 90 as shown in FIG. In addition, since the thickness t1 of the end electrode 40 is as thin as 8 μm or less, even if the end of the suction nozzle 90 is positioned on the end electrode 40, the suction action is not significantly reduced by the suction nozzle 90, and sufficient suction power is obtained. The parts can be held with.

The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.
For example, the specific cross-sectional structure of the coil chip component according to the present invention is not limited to the embodiment shown in FIG. 1 and may have various aspects.

FIG. 1 is a longitudinal sectional view of a coil chip component as a surface mount electronic component according to an embodiment of the present invention. 2 is a cross-sectional view of the main part of the mold showing an example of the manufacturing process of the coil chip component shown in FIG. 3 is a cross-sectional view of a main part of the coil chip component shown in FIG. FIG. 4 is a schematic perspective view showing a state where the coil chip component shown in FIG. 1 is sucked by a suction nozzle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 ... Coil chip component 4 ... Drum core 4a ... Core part 4b ... 1st flange 4c ... 2nd flange 5 ... Element main body 10 ... Coil part 10a ... Wire 10b, 10c ... Connection part 20 ... Underlayer electrode layer 30 ... Exterior resin Part 30a ... Flange coating part 30b ... Flat surface 40 ... End electrode 50 ... Stepped recess 60 ... Substrate 70 ... Solder 80, 82 ... Mold 84 ... Cavity 86 ... Holding convex part 88 ... Circumferential clearance 90 ... Adsorption nozzle

Claims (5)

A core portion having a pair of square flanges at both axial ends of the core portion;
A wire wound around the core portion;
A resin flange covering portion covering the connecting portion of the wire located on the outer periphery of each flange halfway;
An exterior resin portion formed integrally with the flange covering portion, covering the periphery of the wire wound around the core portion, and having a flat surface on at least one surface;
A pair of end electrodes formed so as to directly cover the outer peripheral surface of the flange from the end surface of the flange and to cover the flange covering portion of the exterior resin portion so as to be connected to the connecting portion of the wire Have
A surface-mount type electronic component, wherein a flat surface of the exterior resin portion is an adsorption surface.   2. The surface-mount type electronic component according to claim 1, wherein an axial length of the flat portion of the exterior resin portion not covered with the end electrode is 30 to 70% of the total length of the electronic component.   The surface-mount electronic component according to claim 1, wherein the end electrode has a thickness of 8 μm or less.   The surface-mount type electronic component according to any one of claims 1 to 3, wherein a stepped concave portion continuous in a circumferential direction is formed on an outer peripheral surface of each end electrode. Preparing a core portion having a pair of square flanges at both axial ends of the core portion;
Forming a coil part by winding a wire around the core part; and
Forming a connecting portion of the wire on the outer periphery of the flange;
The core portion around which the wire is wound is arranged in the mold in at least one line in the axial direction, and the end surfaces of the flanges in the adjacent core portions are in contact with each other, and on the flange outer periphery of the end surface where these flanges contact. Forming a cavity on the outer periphery of the coil part and the outer periphery of the flange part by contacting the holding convex part of the mold; and
Resin is injected into the cavity, and a resin flange covering portion covering the connecting portion of the wire located on the outer periphery of each flange to the middle, and the flange covering portion are formed integrally, covering the periphery of the coil portion And a step of molding an exterior resin portion having a flat surface on at least one surface thereof.

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