JP2006222313A - Electronic component and manufacturing method thereof and flow soldering mounting substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the adhesion of solder to a part of a lead of an electronic component. <P>SOLUTION: Molding is carried out with a molding resin material, to which solder does not adhere, over the upper surface of a large lead provided for heat dissipation of the electronic component to prevent a solder bridge upon flow soldering of a lead terminal of the electronic component to a substrate. Further, in the molding process for molding the molding resin, a molding die is used for molding the electronic component with the molding resin which can also be used for molding the molding resin material, to which the solder does not adhere, over the upper surface of the large lead provided for heat dissipation, so that the molding resin is simultaneously molded over the upper surface of the large lead provided for heat dissipation to prevent the solder bridge of the lead terminal. The electronic component is provided as capable of preventing the adhesion of solder to a part of the lead of the electronic component and the manufacturing method thereof and a flow soldering mounting substrate are provided to solve the above-mentioned problem. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a technique for preventing a solder bridge of a lead terminal portion when a surface mounting electronic component having a plurality of leads is flow soldered.

  The surface mounting electronic component has been developed as a component for reflow soldering, but the flow soldering technique has been improved and a considerable surface mounting electronic component has been used for flow soldering.

  FIG. 8 is a perspective view of a structure showing an example of a conventional surface mounting electronic component (hereinafter abbreviated as an electronic component). The general structure is that a resin mold body 1 in which a chip or the like (not shown) is molded with various molding resin materials, and a solder joint land 11 formed on the substrate 10 in FIG. 8 is generally provided, but the electronic component shown in FIG. 8 is used as a driver IC for a motor or the like, and these generate great heat. A heat radiation lead 2 is provided which is enlarged.

  When soldering an electronic component, as shown in FIG. 9, the lead 3 (including the heat dissipation lead 2) of the electronic component shown in FIG. 8 is placed on the solder joint land 11 and the heat dissipation land 12 provided on the substrate 10. ) And soldering in accordance with the board flow direction 111, and the lead 2 for heat dissipation is connected so that the electrical signal of each lead 3 can be obtained and the heat generated by the electronic component body is dissipated. It is.

  In addition, when performing this soldering, the adhesive agent not shown is supplied to the lower part of the resin mold main body 1 in advance, and the resin mold main body 1 is bonded and fixed at a predetermined position on the substrate 10.

  However, when soldering a conventional electronic component as shown in FIG. 8, the lead 3 and the heat dissipation lead 2 of the electronic component are connected to the solder bonding land 11 and the heat dissipation land 12 formed on the substrate 10 of FIG. It was aligned above and soldered in a flow bath.

  At this time, in order to eliminate a solder bridge generated during solder joining, a solder absorbing land 13 is generally provided as shown in the substrate 10 of FIG.

  If the solder absorbing lands 13 are general electronic parts (not shown) and only a plurality of leads 3 having the shape of the leads 3 are formed on both sides of the resin mold main body 1, Since excess solder at the rear end can be absorbed, solder breakage of the lead 3 at the rear end of the electronic component is improved, and no solder bridge is generated.

  However, in the case of an electronic component having a large heat dissipation lead 2 provided to dissipate the heat generated by the electronic component as shown in FIG. 8, when it is placed and flow soldered as shown in FIG. 9, it is shown in FIG. As described above, a large amount of the solder adhering portion 21 is formed on the heat dissipation lead 2, reducing the solder breakage effect of the absorption solder 22 to be absorbed by the solder absorption waste land 13 formed at the rear end, and the heat dissipation lead 2. There is a problem that many solder bridges 23 are generated in the vicinity of the lead 3 at the rear end, causing a short circuit.

  In order to solve the above problems, an object of the present invention is to provide an electronic component that can prevent adhesion of solder to a part of a lead portion of the electronic component, a manufacturing method thereof, and a flow soldered mounting board.

  In order to achieve the above-mentioned object, the present invention is to mold the upper surface portion of a large lead provided for heat dissipation of an electronic component with a molding resin material to which solder does not adhere, and flow solder the lead terminal of the electronic component to a substrate. It is characterized by preventing solder bridging when attaching.

  In the resin molding process for molding electronic parts, the present invention provides a molding resin material in which solder does not adhere to the upper surface portion of a large lead provided for heat dissipation in the molding resin molding mold for electronic parts. A mold that can be formed is used, and an upper surface portion of a large lead provided for heat dissipation is simultaneously molded with a molding resin to prevent solder bridges of the lead terminals.

  According to the present invention, it is possible to eliminate a solder bridge generated when soldering a surface mount electronic component having a thick lead in a part of a lead in a flow soldering bath, and the reliability of soldering is greatly increased. The cost can be reduced.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIG. 1 is a perspective view of an overall image showing a structure formed by a lead upper surface resin mold 4 on the entire upper surface of a heat radiating lead 2 of an electronic component according to the present invention.

  2 and 3 are molded on the upper surface of the heat radiating lead 2 as in FIG. 1. As a modification of the lead upper surface resin mold 4, a lead upper surface resin mold a4-1 and a lead upper surface resin mold b4-2 are shown. It is a figure which shows the cross-sectional shape when thickness etc. are changed like FIG.

  FIG. 4 is a diagram showing a structure in which a comb-like resin mold 5 is molded on the upper surface portion of the heat dissipation lead 2 of the electronic component according to the second embodiment of the present invention, and (a) is a plan view of the whole image, (B) is AA sectional drawing.

  These lead upper surface resin molding materials are basically the same resin as the material of the resin mold main body 1, but other materials that can be molded are also possible.

  FIG. 5 shows the same form as that of the second embodiment of the present invention, but a flexible material is used as the material used, and a comb-like resin mold a5-1 is formed on the upper surface of the heat dissipation lead 2 of the electronic component. It is a figure which shows the structure which carried out, (a) is a top view which shows the whole image, (b) is BB sectional drawing.

  These solder bridge prevention methods in FIG. 1 to FIG. 5 are for molds in which solder is not attached with a new molding die after the heat-dissipation leads 2 and electrical signal leads 3 of the electronic components are formed into the required shapes. A resin material was molded.

  In the electronic component shown in FIG. 6, when the resin mold main body 1 is molded, the upper surface portion of the heat dissipation lead 2 is also molded at the same time. As the shape at the time of molding, each plane avoiding each bent portion of the heat dissipation lead 2. The lead upper surface resin mold 64 that avoids the bent portion is formed only in the portion, thereby forming each lead.

  Further, FIG. 7 is formed at the same time as the resin mold body 1 is molded as in FIG. 6 and finished like a comb-shaped resin mold 74 avoiding a bent portion whose shape is comb-shaped. Various shapes are possible, and this forming method eliminates the need for an extra mold, shortens the manufacturing process, and avoids an increase in cost.

  FIG. 1 is a perspective view of an electronic component according to a first embodiment of the present invention. The resin mold body 1 in the figure uses an epoxy-based resin material for molding, and is formed by molding a molding die (not shown) with a chip or a connecting wire (not shown) inside, and a lead (not shown) after molding. The lead 2 for heat dissipation and the lead 3 are formed by molding as shown in the figure.

  Next, a dedicated die (not shown) is used on the entire upper surface of the heat dissipation lead 2 of the molded electronic component, and the lead upper surface resin mold 4 is made of an epoxy-based molding resin material used for the resin mold main body 1. Was molded.

  Further, FIGS. 2 and 3 show cross-sectional views when the lead upper surface resin mold 4 is molded as a modification of the lead upper surface resin mold 4 in the same manner as in FIG. The upper surface resin mold a4-1 and the lead upper surface resin mold b4-2 are finished.

  In order to confirm the effect of this embodiment, the solder when flow soldering processing is performed on a dedicated board (not shown) using the electronic component of this embodiment finished in various shapes and the conventional electronic component shown in FIG. Table 1 shows the finishing results.

Soldering conditions ・ Board size: 200 * 200 mm
-Number of parts mounted: 20 each sample-Number of processed boards: 50-Soldering equipment: Nippon Denso Keiki / LS-350SS
Solder material: Sn-3Ag-0.5Cu
Solder temperature: 255 ° C
-Preheating temperature: 120 ° C
・ Substrate transport speed: 1.1 m / min

表１の結果からも分かるように、本発明の電子部品で大型リード上面部にはんだが付着しない樹脂材料を成型することで、大型リード部のはんだ溜まりが無くなり、リードの先端部のみにはんだが形成されるためはんだの付着量が減り、従来から用いられているはんだ吸収用捨てランドにはんだが吸収され易くなり、はんだブリッジの大幅な軽減が図られた。

As can be seen from the results in Table 1, by molding a resin material that does not allow solder to adhere to the upper surface of the large lead in the electronic component of the present invention, there is no solder pool in the large lead, and solder is only applied to the tip of the lead. As a result, the amount of solder adhered is reduced, the solder is easily absorbed into the conventionally used waste land for absorbing solder, and the solder bridge is greatly reduced.

  FIG. 4 shows an electronic component that is a second embodiment of the present invention. 4A is a plan view seen from above, and FIG. 4B is a cross-sectional view taken along the line AA. The resin mold main body 1 in the figure uses an epoxy mold resin material as in Example 1 and is molded with a chip (not shown), a connection wire, etc., and is molded by a lead molding machine (not shown) after molding. The heat radiation lead 2 and the lead 3 are formed in the same manner as in the first embodiment as shown in the figure.

  Next, on the upper surface portion of the heat dissipation lead 2 of the molded electronic component, a dedicated mold (not shown) that can be molded in a comb shape toward the tip of the lead is used, and the epoxy system used for the resin mold body 1 is used. The comb-shaped resin mold 5 was molded with the mold resin material.

  The effect of the example according to the present invention was the same as that of Example 1.

  An electronic component according to a third embodiment of the present invention is shown in FIG. FIG. 5A is a plan view seen from above, and FIG. 5B is a cross-sectional view taken along the line BB. There is a dedicated mold (not shown) that can be molded in a comb-tooth shape toward the tip of the lead as in the second embodiment on the upper surface of the heat dissipation lead 2 of the molded electronic component. Comb-shaped resin mold a5-1 was molded using a flexible material.

  The effect of the example according to the present invention was the same as that of Example 1.

  The perspective view of the electronic component which is the 4th Example of this invention is shown in FIG.6 and FIG.7. The electronic component shown in FIG. 6 according to this embodiment is a mold used when the resin mold body 1 is molded by a lead upper surface resin mold 64 that avoids a bent portion formed on the upper surface portion of the heat dissipation lead 2. The material is molded at the same time, and the shape is such that the resin material for molding at each bent portion of the heat dissipation lead 2 is deleted, and the resin material for molding is left only on the flat surface, and the heat dissipation lead 2 and the lead 3 in the subsequent process. The lead upper surface resin mold 64 avoiding the bent portion can be formed without being broken at the time of cutting and forming.

  Further, FIG. 7 shows a change in the shape of the lead upper surface resin mold, in which the molding resin material is molded on a part of the surface portion excluding the bent portion of the heat dissipation lead 2. A comb-shaped resin mold 74 is formed so as to avoid a bent portion formed in a comb-tooth shape toward the tip end of the lead 2 for use.

  As a result of performing flow soldering using both of these electronic components in the same manner as in Example 1, a soldering result with few bridges was obtained as in Example 1.

It is a perspective view which shows the structure which shape | molded only the upper surface part of the radiation | emission lead in Embodiment 1 of this invention with the resin material for molds. It is sectional drawing which shows the structure which thinly shape | molded only the upper surface part of the radiation | emission lead with the resin material for molds in the other form in Embodiment 1 of this invention along the lead shape. The cross section which shows the structure which shape | molded only to the front-end | tip with the resin material for molding so that only the upper surface part of the radiation | emission lead may become the same surface as the resin mold upper surface of a main body by the other form in Example 1 of this invention. FIG. FIG. 6 is a plan view (a) and a cross-sectional view (b) showing a structure in which only the upper surface portion of the heat dissipation lead is directed toward the distal end of the heat dissipation lead in a second embodiment of the present invention and the molding resin material is formed in a comb-tooth shape is there. FIG. 9 is a plan view showing a structure in which only the upper surface portion of the heat radiating lead is directed toward the tip of the heat radiating lead in Example 3 of the present invention, and a flexible molding resin material is molded into a comb shape. It is figure (a) and sectional drawing (b). It is a perspective view which shows the structure which shape | molded the resin material for molds in the upper surface whole surface part except the bending part of the radiation | emission lead in Example 4 of this invention. The top view which shows the structure which shape | molded the resin material for molding in the top surface part except the bending part of the heat radiation lead in the other form in Example 4 of this invention toward the front-end | tip direction of the heat radiation lead in the comb-tooth shape. It is (a) and sectional drawing (b). It is a perspective view which shows the structure of the conventional electronic component. It is a top view which shows one structural example when mounting the conventional electronic component (SOP) on a board | substrate. It is a perspective view which shows the example of a solder bridge defect when the conventional general electronic component (SOP) is mounted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resin mold main body 2 Radiation lead 3 Lead 4 Lead upper surface resin mold 4-1 Lead upper surface resin mold a
4-2 Lead upper surface resin mold b
5 Comb-shaped resin mold 5-1 Comb-shaped resin mold a
DESCRIPTION OF SYMBOLS 10 Board | substrate 11 Soldering land 12 Heat radiation land 13 Solder absorption discard land 111 Board flow direction 20 Solder fillet 21 Solder adhesion part 22 Absorbing solder 23 Solder bridge 64 Lead upper surface resin mold avoiding the bent part 74 Avoiding the bent part Comb-shaped resin mold

Claims (8)

  The upper surface of the large lead provided for heat dissipation of the electronic component is molded with a resin material for molding that does not adhere solder, and the solder bridge when the lead terminal of the electronic component is flow soldered to the substrate is prevented. Features electronic components.   2. The electronic component according to claim 1, wherein the entire upper surface of a large lead provided for heat dissipation of the electronic component is molded with a molding resin material to which solder does not adhere.   2. The electronic component according to claim 1, wherein a resin material for molding is formed on an upper surface portion of a large lead provided for heat dissipation so as to avoid each bent portion of the lead and to prevent solder from adhering to each flat portion.   2. The electronic component according to claim 1, wherein a molding resin material to which solder does not adhere toward the leading end of the lead is formed in a comb-teeth shape on an upper surface portion of a large lead provided for heat dissipation.   2. A molding resin material to which solder does not adhere to an upper surface portion of a large lead provided for heat dissipation, and is molded from any one of a thermoplastic material, a thermosetting material, and a flexible material. The electronic component described.   After molding the lead terminal in the manufacturing process of the electronic component, a mold capable of forming a resin material for molding on which the solder does not adhere to the upper surface portion of the large lead provided for heat dissipation of the electronic component is used. A method of manufacturing an electronic component comprising: setting a component, molding a molding resin only on an upper surface portion of a large lead provided for heat dissipation, and preventing a solder bridge of a lead terminal.   In the resin molding process for molding electronic parts, a mold capable of forming a resin material for molding that does not adhere to the upper surface of a large lead provided for heat dissipation is used in the molding resin molding mold for electronic parts. A method of manufacturing an electronic component, wherein the upper surface portion of a large lead provided for heat dissipation is also molded with a molding resin to prevent solder bridges of lead terminals.   2. A flow soldered mounting board that prevents a solder bridge of lead terminals using the electronic component according to claim 1, wherein a resin material for molding that does not adhere solder is formed on an upper surface portion of a large lead provided for heat dissipation of the electronic component. .

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