JP2007250934A - Molded electronic component and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a molded electronic component which is easily provided with a through-hole and reliable without having a blister of coating resin, coating cracking, etc., due to solder heat and can be made thin; and to provide a method of manufacturing the same. <P>SOLUTION: The molded electronic component formed by molding a coil component 1 having a core 2 with the coating resin 3 has a recess 3b formed in the coating resin 3 on the core 2 of the coil component 1 without reaching the surface 1a of the core, and also has the through-hole 3a bored in the bottom 3c of the recess by using a laser etc. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a molded electronic component obtained by molding a surface mount electronic component such as an inductor or a transformer with an exterior resin.

  In such electronic components, the electronic devices incorporating these electronic components are required to be reduced in size and thickness, and these electronic components are also required to be reduced in size and thickness. For this reason, as shown in FIG. 3, it is required to reduce the thickness t of the exterior resin 3 that covers the upper surface of the core 2 of the coil component 1 mounted on the substrate. However, when the exterior resin 3 is molded or reflowed, that is, when the temperature of the exterior resin 3 or the coil component 1 rises, moisture contained in the core 2 and the exterior resin 3 evaporates or the core 2 and the exterior resin 3 Since the air contained in the resin 3 or in the core expands, as shown in FIG. 4, the exterior resin of the upper part 2a of the core 2 expands (d), or cracks are produced, thereby reducing the quality of the product. However, the yield decreases.

  In particular, when the core 2 is formed of a powder molded body such as a ferrite core, the core tends to contain air, and in the case of a mold resin such as an epoxy resin containing ferrite powder or a liquid crystal polymer, the adhesion to the core is low. Since the air is low, an air layer is formed between the two, and the air is easily expanded by heat during reflow for soldering the electronic component to the substrate. In addition, when the thing with high adhesiveness of exterior resin 3 and a core is selected, since the mold separation from a mold for mold worsens and the mold becomes easy to get dirty, select one with very high adhesiveness for exterior resin. I can't.

  As a method for preventing the outer resin of the upper part 2a of the core 2 from swelling or cracking, as shown in FIG. After that, Patent Document 1 discloses a method of molding the exterior resin 3.

  However, in the structure in which the core is coated with the coating resin as the base material, a step of applying the coating resin to the upper surface of the core in advance and a step of drying are necessary. In addition, the coating thickness is required to be uniform, and depending on the coating resin coating variation, the adhesion with the core becomes non-uniform and swells, and cracks are considered dangerous.

On the other hand, as shown in FIG. 6, Patent Document 2 describes that a through hole 3a is provided in the exterior resin of the core upper surface portion 2a. According to this method, there is no problem of Patent Document 1. It is possible to prevent resin swelling, cracks, and the like at the intended core upper part.
However, if the through-hole is directly provided by molding, the core is hit directly on the upper surface of the core, causing damage to the core, cracking, chipping, and the like. Further, the pressure contact strength of the protruding pin must be taken into account, and the structure of the protruding pin in the mold becomes complicated and expensive. For this reason, it is difficult to make the core ridges thin. Further, if the thickness of the exterior resin is reduced, the hole diameter cannot be reduced because peeling due to the protruding pin, burrs and the like are generated.

JP 2000-58335 A JP 2000-58336 A

  The present invention has been made in view of the above-described problems, and is a molded electronic device that can be easily provided with a through-hole, and can be reduced in thickness without causing blistering of outer packaging resin or generation of outer cracking due to soldering heat. A component and a method for manufacturing the component are provided.

  The molded electronic component of the present invention is a molded electronic component in which a coil component having a core is molded with an exterior resin, and a recess is formed on the exterior resin on the top of the core of the coil component so as not to contact the surface of the core. A through-hole is formed in the bottom of each of the above.

  The method of manufacturing a molded electronic component according to the present invention includes a molded electronic component obtained by molding a coil component having a core with an exterior resin, and the exterior resin provided on the exterior resin of the upper part of the core of the coil component is provided with a recess that does not contact the surface of the core. A resin molding step and a step of forming a through-hole using a laser or the like at the bottom of the recess of the exterior resin provided at the time of molding are provided.

  The molded electronic component of the present invention is a molded electronic component in which a coil component having a core is molded with an exterior resin, and a recess is formed on the exterior resin on the top of the core of the coil component so as not to contact the surface of the core. Since the through-hole is further formed using a laser or the like, the through-hole can be made smaller, and the core protrusion pin does not directly hit the top surface of the core, causing damage to the core, cracking, chipping, etc. There is nothing. By providing the through hole, it is possible to reduce the thickness and reduce the thickness of the exterior resin due to solder heat and the occurrence of exterior cracks. Further, even when the recess is provided, since the protrusion pin of the mold only needs to be a fixed protrusion, the mold structure is simple and can be made inexpensive.

FIG. 1 is a cross-sectional view showing an embodiment of a molded electronic component according to the present invention.
FIG. 1 shows a single coil component configured as a transformer or an inductor. The present invention is applied to a coil component 1 such as a transformer composed of a drum-shaped core 2 made of ferrite and a coil 4 and molded with an exterior resin 3. It is an embodiment. That is, the through-hole 3a is provided in the exterior resin 3 at the center of the upper surface 2a of the core 2.
However, the through hole 3a is provided in two stages including a recess 3b at the time of molding and a through hole 3c by laser processing after molding. As the exterior resin, an epoxy heat-resistant resin may be used, or a resin containing ferrite that reduces noise radiating to the outside and noise flying from the outside may be used.

  FIG. 2 is a cross-sectional view for explaining a method for manufacturing a molded electronic component according to the present invention.

  FIG. 2 is a manufacturing method for forming the through hole 3a of the molded electronic component shown in FIG. 1, and FIG. 2 (a) is a cross-sectional view for forming the recess 3b, which is the first step for forming the through hole 3a. It is. FIG. 2B is a cross-sectional view of laser machining the bottom 3c of the recess, which is the second step. FIG.2 (c) is sectional drawing which shows the state which the through-hole 3a was completed.

  In the first step, as shown in FIG. 2A, the recess 3b is formed by the protruding pin 10a of the mold 10 so that a part of the exterior resin on the upper surface of the core remains. The depth of the recess 3b is set by a preset length of the protruding pin 10a, and the protruding pin 10a sets a gap g that does not press the core upper surface 2a, that is, a part of the exterior resin 3 remains. Thickness. The shape of the protruding pin of the mold can be reduced by squeezing along the tip (tapered shape), thereby facilitating die cutting and preventing the occurrence of burrs on the opening surface of the recess.

In the second step, as shown in FIG. 2B, the bottom exterior resin of the recess 3b is further processed using a laser or the like to form the hole 3c. FIG. 2C shows a state in which the through hole 3a is completed.

The size of the through hole 3a is such that the appearance and the adsorption error in mounting are not impaired.
For example, in this embodiment, the outer dimension of the coil including the exterior resin is vertical and horizontal 14 mm square. At a height of 2.7 mm, when the core diameter is 12 mmφ, the brim thickness is 0.5 mm, and the resin thickness of the upper surface of the core is 0.5 mm, the depth of the recess 3b at the time of molding is 0.4 mm, and the depth of the laser processing 3c. The hole diameter can be reduced to about 0.2 mm with a thickness of 0.1 mm. About 0.5 mm is the minimum in the hole diameter in the conventional metal mold | die. The laser device is a commonly used laser marker (CO2 or YAG) for printing or a YAG laser for welding, and the irradiation energy is about 2.5 J.

Thus, the through-hole 3a provided in the exterior resin 3 of the core upper portion 2a can release air or vapor expanded by heat during reflow from the through-hole 3a, and the exterior resin 3 can be swollen or peeled off or cracked. Generation can be eliminated.
Furthermore, since the concave portion is provided so that the protruding pin of the mold is not directly applied to the upper surface of the core at the time of molding, the molding can be performed without damaging the core.

Furthermore, since the resin between the bottom of the recess and the core can be easily removed by processing with a laser or the like, the core can be prevented from being damaged without being damaged.
For this reason, the thickness of the exterior resin 3 on the upper part of the core 2 can be made thinner than before. Therefore, quality improvement and yield improvement can be achieved. Further, the thickness h of the upper part of the core 2 can be reduced, and as a result, the thickness of the entire part can be reduced. Further, since the yield is improved and the thickness is reduced, the size and cost can be reduced.

  The molded electronic component and the manufacturing method thereof according to the present invention are not limited to these examples. For example, the core used for the coil component is not limited to the drum type, and may be a combination type core such as EI type or EE type, and the through hole is preferably provided at the center of the core surface, but only at one place. A plurality of them may be provided.

Sectional drawing which shows one Embodiment of the molded electronic component by this invention. Sectional drawing which shows the manufacturing method which forms the through-hole of the mold electronic component shown in FIG. Sectional drawing which shows the conventional mold electronic component. Sectional drawing which shows the swelling of exterior resin in the conventional mold electronic component. Sectional drawing which shows one Example of the swelling prevention of the conventional mold electronic component. FIG. 10 is another cross-sectional view showing an example of prevention of swelling of a conventional molded electronic component.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coil component 2 Core 3 Exterior resin 3a Through-hole 3b Recessed part 3c Processed hole 4 Coil 6 Terminal

Claims (4)

In a molded electronic component in which a coil component having a core is molded with an exterior resin,
A molded electronic component, wherein a concave portion that does not contact the surface of the core is molded in an exterior resin at the top of the core of the coil component, and a through hole is formed at the bottom of the concave portion. 2. The mold electronic component according to claim 1, wherein a laser marker (CO2 or YAG) for printing or a YAG laser for welding is used for the first through-hole. In a molded electronic component in which a coil component having a core is molded with an exterior resin,
An exterior resin molding process in which a recess is formed in the exterior resin on the upper part of the core of the coil component so as not to contact the surface of the core, and a bottom hole of the recess in the exterior resin provided at the time of molding is formed with a laser or the like. And a step of forming the mold electronic component manufacturing method. 3. The method of manufacturing a molded electronic component according to claim 2, wherein a laser marker (CO2 or YAG) for printing or a YAG laser for welding is used as the first stage laser.

Images