Mounting methods for electronic components

Abstract

To suppress cost increase in a facility due to use of an anisotropic conductive junction member and easily mount an electronic component on a surface of a substrate.SOLUTION: An electronic component (connector 100) comprises a first connection part (lead part 21) and a second connection part (terminal part 32) which are respectively connected to lands 210, 220 of a substrate 200. An anisotropic conductive junction member 40 is attached to a region where the first connection part is located. In the anisotropic conductive junction member 40, solder particles are dispersed in a resin. The resin has the lower fusion temperature than the melting point of the solder particles. Cream solder 230 is printed on the land 220 of the substrate 200 connected to the second connection part. An electronic component is mounted on the substrate 200, is made to pass through a reflow furnace and is heated, thereby connection between the second connection part and the land 220 of the substrate 200 by reflow soldering and connection between the first connection part and the land 210 of the substrate 200 via the anisotropic conductive junction member 40 are simultaneously performed.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] This invention relates to an electronic component surface-mounted on a substrate. Quality Regarding implementation methods. [Background technology]

[0002] Methods for surface mounting electronic components on a substrate include, for example, reflow soldering and thermocompression bonding using ACF (Anisotropic Conductive Film). Patent Document 1 describes mounting chip components, which are electronic components, by soldering, and mounting IC chips, which are electronic components, by thermocompression bonding using ACF.

[0003] FIG. 6 shows a process diagram of the electronic component mounting method described in Patent Document 1, in which the reflow soldering process Pa is performed first, followed by the thermocompression bonding process Pb.

[0004] In the reflow soldering process Pa, solder is printed onto the terminals of the chip component mounting area of ​​the board (process P1), electronic components (chip components) such as electrolytic capacitors are mounted onto the terminals (process P2), and then the board with the electronic components mounted is transported into a reflow furnace, where hot air is supplied (process P3), which melts the solder and solders the electronic components.

[0005] After the reflow soldering process Pa is completed, the operation proceeds to the thermocompression bonding process Pb, in which the ACF is first attached, or placed, on the IC chip mounting area of ​​the board (process P4). After the ACF is attached, the IC chip is mounted (process P5), and then a heated head presses the IC chip onto the board (process P6). This causes the resin in the ACF to adhere the entire IC chip to the surface of the board, and the conductive particles in the ACF conductively connect the bumps on the IC chip to the corresponding leads on the board.

[0006] In this way, in Patent Document 1, various electronic components are surface-mounted on a substrate by sequentially performing both the reflow soldering process Pa and the ACF thermocompression bonding process Pb. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-314236 Summary of the Invention [Problem to be solved by the invention]

[0008] As in the case of the IC chip mounting method described in Patent Document 1, ACF can be used to connect multiple electrodes at once and to achieve fine connections. Therefore, it is desirable to use ACF when surface mounting a micro connector having multiple contacts arranged at a narrow pitch (fine pitch) on a substrate.

[0009] On the other hand, since a connector is subjected to external forces when inserted into or removed from a mating connector, if the connector is mounted on a board only by joining with an ACF, the ACF's bonding strength is weak and there is a risk that the external force will cause the joint to peel off. Therefore, when using an ACF to mount a connector on a board in this way, it is preferable to ensure the bonding strength with the board, i.e., the attachment strength of the connector to the board, by, for example, providing a reinforcing metal fitting on the connector and soldering the reinforcing metal fitting to the board.

[0010] When a reinforcing metal fitting is provided on such a tiny connector, the terminal portion of the reinforcing metal fitting soldered to the board and the lead portion of the contact connected to the board via the ACF are inevitably close to each other, i.e., the land on the board to which the terminal portion of the reinforcing metal fitting is connected and the land to which the lead portion of the contact is connected are close to each other.When attaching an ACF to such a board, high-precision positioning is required so that the ACF is positioned only on the specified lands (group of lands).For example, depending on the connector specifications, high-precision positioning accuracy of ±0.05 mm is required.

[0011] To mount an ACF on a board with such high positioning accuracy, it is necessary to modify or add equipment to the series of processes and equipment used in a typical automated machine that performs surface mounting of electronic components on a board, such as printing cream solder on the board, mounting the electronic components, and passing the board through a reflow oven.However, modifying or adding equipment to a typical large-scale automated machine that performs surface mounting of electronic components on a board is costly.

[0012] In view of the above circumstances, an object of the present invention is to provide an electronic component that is surface-mounted on a substrate and has connection parts that are connected via an anisotropic conductive bonding material and connection parts that are connected by solder. Quality To provide a simple mounting method. [Means for solving the problem]

[0013] According to this invention, in a method for mounting an electronic component to be surface-mounted on a substrate, the electronic component has a first connection portion and a second connection portion that are respectively connected to lands on the substrate, and an anisotropic conductive bonding material is attached to the area where the first connection portion is located, and the anisotropic conductive bonding material is a resin in which solder particles are dispersed, and the resin has a melting temperature lower than the melting point of the solder particles, and cream solder is printed on the land of the substrate that is to be connected to the second connection portion, and the electronic component is mounted on the substrate and passed through a reflow furnace and heated, thereby simultaneously connecting the second connection portion to the land of the substrate by reflow soldering and connecting the first connection portion to the land of the substrate via the anisotropic conductive bonding material. [Effects of the Invention]

[0015] According to this invention, surface mounting of an electronic component having a connection part connected via an anisotropic conductive bonding member and a connection part connected by solder onto a substrate can be easily performed while suppressing the increase in equipment costs associated with the use of an anisotropic conductive bonding member. [Brief explanation of the drawings]

[0016] [Figure 1] 1A is a partially exploded perspective view of an embodiment of an electronic component as seen from above, and FIG. 1B is a partially exploded perspective view of an embodiment of an electronic component as seen from below. [Figure 2] 1A is a perspective view showing an embodiment of an electronic component as seen from above, and FIG. 1B is a perspective view showing the electronic component shown in FIG. 1A as seen from below. [Figure 3] 2B is a perspective view showing an outline of a substrate on which the electronic component shown in FIG. 2A is surface-mounted. [Figure 4] 2B is a perspective view showing how the electronic component shown in FIG. 2A is mounted on a substrate. [Figure 5] 2B is a perspective view showing a state in which the electronic component shown in FIG. 2A is mounted on a substrate. [Figure 6] FIG. 1 is a process diagram showing a conventional example of a mounting method for electronic components. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described by way of example with reference to the accompanying drawings.

[0018] Figures 1 and 2 show the surface mounted Ruden A connector is shown as an example of a sub-component, with FIG. 1 showing a partially disassembled state and FIG. 2 showing the completed connector.

[0019] In this example, the connector 100 is composed of a resin housing 10, a large number of contacts 20 arranged and held in the housing 10, a pair of reinforcing metal fittings 30, and an anisotropic conductive joining member 40.

[0020] The housing 10 is a flat, elongated, roughly rectangular parallelepiped, and in this example, 26 contacts 20 are attached to the housing 10 in two rows of 13 contacts each. Lead portions 21 of the contacts 20, which are connected to lands on the board, are located on the underside of the housing 10.

[0021] A pair of reinforcing metal fittings 30 are attached to both longitudinal ends of the housing 10, and each of these reinforcing metal fittings 30 has an upper plate portion 31 that is positioned to cover the upper surface of the longitudinal end of the housing 10, and a terminal portion 32 that is bent and extended from the upper plate portion 31 along the side surface of the housing 10 and reaches the underside of the housing 10. In this example, three terminal portions 32 are provided on one reinforcing metal fitting 30.

[0022] In this example, the anisotropic conductive joining member 40 is a rectangular film-like material in which solder particles are dispersed in a resin. The resin constituting the anisotropic conductive joining member 40 may be a thermoplastic resin or a thermosetting resin, and is melted at a temperature lower than the melting point of the solder particles.

[0023] The anisotropic conductive bonding member 40 is attached at low temperature and low pressure to the lower surface of the housing 10 in the area where the lead portions 21 of the 26 contacts 20 are located, as shown in FIG.

[0024] In this example, the connector 100 is equipped with the anisotropic conductive joining member 40, but connector assembly is generally performed by an automated machine, and automated machines that assemble minute connectors with many contacts arranged at narrow pitches have high-precision positioning mechanisms. Therefore, the anisotropic conductive joining member 40 can be positioned and attached with high precision using this mechanism. In other words, it is sufficient to simply incorporate the process of attaching the anisotropic conductive joining member 40 into the automated machine that assembles the connector, which requires minimal changes to the equipment and reduces costs.

[0025] FIG. 3 shows a substrate 200 on which the above-mentioned connector 100 is surface-mounted. In FIG. 3, only the portion of the substrate 200 on which the connector 100 is surface-mounted is shown, and other portions are omitted from the illustration.

[0026] Twenty-six lands 210 are formed on the surface of the substrate 200 corresponding to the lead portions 21 of the 26 contacts 20 of the connector 100, and six fixed lands 220 are formed corresponding to a total of six terminal portions 32 of a pair of reinforcing metal fittings 30.

[0027] A method for surface mounting the connector 100 onto the substrate 200 will now be described.

[0028] First, cream solder is printed and applied to the lands 220 of the substrate 200 to which the terminal portions 32 of the reinforcing metal fittings 30 of the connector 100 are connected, and cream solder 230 is placed on the lands 220 as shown in FIG.

[0029] Next, the connector 100 is positioned and mounted on the board 200 as shown in Fig. 5, and is then passed through a reflow oven and heated. This melts the cream solder, connecting the terminal portions 32 of the reinforcing metal fittings 30 of the connector 100 to the corresponding lands 220 on the board 200 with the solder. Furthermore, the resin of the anisotropic conductive joining member 40 melts, and the solder particles melt, connecting the lead portions 21 of the contacts 20 of the connector 100 to the corresponding lands 210 on the board 200 with the molten solder particles.

[0030] Thus, in this example, a single reflow process simultaneously connects the terminal portion 32 of the reinforcing metal fitting 30 to the land 220 of the substrate 200 by reflow soldering, and connects the lead portion 21 of the contact 20 to the land 210 of the substrate 200 via the anisotropic conductive bonding material 40. As described above, the anisotropic conductive bonding material 40 achieves bonding by melting its resin and solder particles, so no pressure is required and bonding can be achieved without load.

[0031] In the above example, the anisotropic conductive joining material is a resin in which solder particles are dispersed, but this is not limiting; a thermocompression type anisotropic conductive joining material that requires heating and pressure, such as a resin in which nickel particles are dispersed, can also be used. In this case, the connector is pressed onto the board with a holding jig, and the anisotropic conductive joining material is passed through a reflow furnace under pressure and heated, allowing even a thermocompression type anisotropic conductive joining material to be joined in the reflow process.

[0032] The above is an example of a connector. Electric Child parts According to this invention Although the mounting method has been described, the electronic component is not limited to a connector, and may be any component surface-mounted on a substrate and having a first connection portion connected to a land on the substrate via an anisotropic conductive bonding material and a second connection portion connected to the land on the substrate by soldering. In the connector 100 described above, the lead portion 21 of the contact 20 forms the first connection portion, and the terminal portion 32 of the reinforcing metal fitting 30 forms the second connection portion. In the connector 100, the reinforcing metal fitting 30 is soldered to the substrate 200 to ensure attachment strength (joint strength) to the substrate 200. However, other examples of the second connection portion requiring soldering include terminals for large currents.

[0033] In addition, in the above example, the anisotropic conductive bonding member placed in the area where the first connection portion is located is attached by pasting a film-like material, but it may also be formed into a film-like material by applying a paste-like material, for example. [Explanation of symbols]

[0034] 10 Housing 20 Contacts 21 Lead part 30 Reinforcement metal fitting 31 Upper plate portion 32 Terminal portion 40 Anisotropic conductive joining material 100 Connector 200 boards 210,220 lands 230 Cream solder

Claims

1. A mounting method for an electronic component to be surface-mounted on a substrate, comprising the steps of: the electronic component has a first connection portion and a second connection portion that are respectively connected to lands on the substrate, and an anisotropic conductive bonding material is attached to a region where the first connection portion is located; the anisotropic conductive joining member is a resin in which solder particles are dispersed, and the resin has a melting temperature lower than the melting point of the solder particles; printing cream solder on a land of the substrate to be connected to the second connection portion; A method for mounting an electronic component, characterized in that the electronic component is mounted on the substrate, passed through a reflow furnace, and heated, thereby simultaneously connecting the second connection portion to the land of the substrate by reflow soldering and connecting the first connection portion to the land of the substrate via the anisotropic conductive bonding material.

2. A mounting method for an electronic component to be surface-mounted on a substrate, comprising the steps of: the electronic component has a first connection portion and a second connection portion that are respectively connected to lands on the substrate, and an anisotropic conductive bonding material is attached to a region where the first connection portion is located; printing cream solder on a land of the substrate to be connected to the second connection portion; a mounting method for an electronic component, characterized in that the electronic component is mounted on the substrate, and the substrate is passed through a reflow furnace while the electronic component is pressed down onto the substrate with a pressing jig, and heated, thereby simultaneously connecting the second connection portion to the land of the substrate by reflow soldering, and connecting the first connection portion to the land of the substrate by thermocompression bonding of the anisotropic conductive bonding member.

3. 3. The electronic component mounting method according to claim 1, The electronic component is a connector in which a plurality of contacts are arranged and held in a housing, and a reinforcing metal fitting is attached to the housing, a reinforcing metal fitting having a terminal portion that is connected to the lead portion of the plurality of contacts and a terminal portion that is connected to the reinforcing metal fitting;

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