JP2014157886A - Circuit board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a circuit board capable of reducing a mounting area without impairing connection reliability of a connection section by a heat cycle, and to provide a method for manufacturing the circuit board.SOLUTION: A circuit board comprises: a substrate 1; a first mounting component 2-1 which is mounted at a first surface of the substrate 1 via first connection members 3-1, and includes one or a plurality of electronic parts; and a second mounting component 2-2 which is mounted at a second surface, facing the first surface, of the substrate 1 via second connection members 3-2, and includes one or a plurality of electronic parts. The first and second mounting components 2-1 and 2-2 are mounted so that a centroid of the first mounting component 2-1 and a centroid of the second mounting component 2-2 are arranged on the same normal line of the substrate 1 at the first surface and the second surface. Each of the first and second connection members 3-1 and 3-2 comprises: a core member formed of an elastic material; and a conductive layer which is formed of a conductive material and covers the surface of the core member.

Description

  The present invention relates to a circuit board for fixing electronic components and a method for manufacturing the circuit board.

  In general, for example, various electronic components are used in electronic devices such as a television, a refrigerator, a vacuum cleaner, a camera, a personal computer, and a mobile phone in order to realize their functions. This electronic component is usually mounted and fixed on a board such as a printed board or a flexible board. The electronic component is, for example, a passive component such as a resistance element or a capacitor, an active component such as a diode or a transistor, and an integrated circuit (including an IC or LSI) in which such an active component is integrated. Among integrated circuits, a component in which passive components are integrated is also known. Conventionally, in such electronic component mounting, insertion mounting technology (THT, through hole technology) has been the mainstream, but when integrated circuits are frequently used, surface mounting technology (SMT, surface mount technology) is the mainstream. It has become. Accordingly, passive components that have been in a form suitable for the insertion mounting technique have also been improved to a form suitable for a surface mounting technique called “chip type” such as a chip resistor or a chip capacitor. With this surface mounting technology, it is possible to reduce the height of the circuit board and increase the density of the mounted components, and it is possible to reduce the size and weight of the electronic device.

  One type of mounting component suitable for this surface mounting technology is a package component called a ball grid array (BGA). The BGA package component includes a package in which electronic components are packaged and a plurality of metal balls arranged on the bottom surface of the package. The plurality of metal balls are lead electrodes for electrically connecting the electronic component in the package and the outside, and are conventionally formed of solder and are called solder balls.

  In a circuit board in which the BGA package component is surface-mounted on a substrate, the solder ball connection portion (joint portion) to the substrate or package is cracked due to a difference in thermal expansion coefficient due to a heat cycle in which heating and cooling are repeated after mounting. (Crack) may occur, and electrical connection may not be maintained. More specifically, for example, the thermal expansion coefficient of silicon constituting the IC chip in the package is about 2.6 ppm / ° C., while the thermal expansion coefficient of glass epoxy constituting the substrate is about 12 to 16 ppm / ° C. In some cases, the thermal expansion coefficients of the two are greatly different from each other. When temperature changes occur due to self-heating of the package (mainly IC chip) or environmental changes, stress is generated due to the difference in the thermal expansion coefficient. This stress gives stress to the connection part (joint part) of the solder ball to the substrate or package, and when the temperature change is repeated (by heat cycle), the accumulation of this stress causes a crack in the connection part of the solder ball, Electrical connection is poor.

  In order to avoid a decrease in connection reliability in the solder balls, for example, a printed wiring board structure disclosed in Patent Document 1 is disclosed. The printed wiring board structure disclosed in Patent Document 1 is a printed wiring board having a first component mounting surface and a second component mounting surface in a front-back relationship, each having a semiconductor package having a semiconductor chip mounted on a substrate as a mounting component. A first semiconductor package mounted on the first component mounting surface in a positional relationship in which the substrates partially overlap each other and the semiconductor chips do not overlap each other via the printed wiring board, and the second And a second semiconductor package mounted on the component mounting surface. According to Patent Document 1, such a printed wiring board structure causes a reduction in connection reliability when an overlap occurs between semiconductor chips (bare chips) (which naturally occurs also between substrates). Semiconductor packages can be mounted on the front and back component mounting surfaces within a range where there is no overlap between semiconductor chips, thereby increasing the density of mounted components and reducing the wiring density without deteriorating connection reliability. (Patent Document 1, paragraph [0012]).

JP 2009-16398 A

  By the way, the printed wiring board structure disclosed in Patent Document 1 has a semiconductor package mounted on each of the component mounting surfaces on the front and back sides within a range in which the semiconductor chips do not overlap each other, thereby further reducing the mounting area. Is difficult.

  The present invention has been made in view of the above circumstances, and its purpose is a circuit board capable of reducing the mounting area without impairing the connection reliability of the connection part (joint part) by heat cycle. And it is providing the manufacturing method of a circuit board.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, a circuit board according to an aspect of the present invention includes a board, a first mounting component that is mounted on one surface of the board via a first connection member and includes one or more electronic components, and the board of the board. A second mounting component including one or a plurality of electronic components mounted on the other surface facing the one surface via a second connection member, wherein the first and second mounting components are the first mounting component The center of gravity and the center of gravity of the second mounting component are mounted so as to be located on the same normal line of the one surface or the other surface of the substrate, and the first and second connection members are each formed of an elastic material. And a conductive layer that is formed of a conductive material and covers the surface of the core member. Preferably, in this circuit board, the first mounting surface of the first mounting component and the second mounting surface of the second mounting component have the same shape.

  In such a circuit board, the first and second mounting components are mounted on both sides of the board, so that the mounting area can be reduced as compared with the case of mounting on one side of the board. And when mounting the first and second mounting components on each of the both surfaces of the substrate, the respective centroids of the first and second mounting components are located on the same normal line of the substrate mounting surface (one surface, the other surface), The first mounting area of the first mounting component and the second mounting area of the second mounting component overlap relatively large in a plane orthogonal to the normal direction, and such a circuit board is planar from the normal direction. The mounting area when viewed can be made relatively small. In particular, when the first mounting surface of the first mounting component and the second mounting surface of the second mounting component have the same shape, the mounting area when viewed in plan from the normal direction is minimized.

  And since such a circuit board is provided with the 1st and 2nd connection member with the core member formed with the elastic material, when each thermal expansion coefficient of a board | substrate, a 1st mounting component, and a 2nd mounting component differs In addition, even if the stress is generated due to the change in temperature and the difference in thermal expansion coefficient, the stress is absorbed and relaxed by the core material of the elastic material in the first and second connecting members. Further, since such a circuit board mounts the first and second mounting components on the both surfaces of the board with the center of gravity of each other overlapped, when the plurality of first and second connection members are plural, The burden can be evenly distributed, and the stress concentration can be reduced. In particular, when the first mounting surface of the first mounting component and the second mounting surface of the second mounting component have the same shape, and each of the first and second connection members is arranged symmetrically with the center of gravity as the center of symmetry. Can be loaded evenly and stress concentration can be minimized. Thus, the circuit board can absorb the stress by the core members of the first and second connecting members, and further reduce the stress concentration, so that the circuit board and the first and second mounting components can be reduced. It is possible to suppress the occurrence of cracks (cracks) that may occur in each connection portion (joint portion) of the first and second connection members.

  Therefore, such a circuit board can reduce a mounting area without impairing the connection reliability of the connection part (joint part) by heat cycle.

  According to another aspect, in the above-described circuit board, the first periphery of the first mounting component or a part of the first periphery and provided between the first mounting component and the substrate, A first reinforcing member that reinforces a connection between the first mounting component and the substrate; and a second periphery of the second mounting component or a part of the second periphery, and the second mounting component and the substrate. It is further provided with at least one of the 2nd reinforcement members which are provided in between and reinforce the connection of the said 2nd mounting components and the said board | substrate.

  Since such a circuit board further includes at least one of the first and second reinforcing members, it is possible to reduce stress concentration on the connection member by bearing the external stress on the entire circuit board against the external stress. it can. For this reason, such a circuit board can improve the reliability of the connection of the connection part (joining part) with respect to the board | substrate and mounting component in a connection member more.

  According to another aspect, in the above-described circuit boards, the first mounting component is a ball grid array package component having the first connection member, and the second mounting component is the second connection member. It is a ball grid array package part having

  According to this configuration, a circuit board is provided in which the package components of the ball grid array are respectively mounted on both sides of the board via the connection member.

  The circuit board manufacturing method according to another aspect of the present invention includes a first mounting step of mounting a first mounting component including one or more electronic components on one surface of the substrate via a first connection member. And a second mounting step of mounting a second mounting component including one or more electronic components on the other surface of the substrate facing the one surface via a second connection member, the first and first The two mounted components are mounted such that the center of gravity of the first mounted component and the center of gravity of the second mounted component are located on the same normal line of the one surface or the other surface of the substrate, and the first and second components are mounted. Each of the connection members includes a core member formed of an elastic material and a conductive layer that is formed of a conductive material and covers the surface of the core member.

  In such a circuit board manufacturing method, the first and second mounting components are mounted on both sides of the board, so that the mounting area can be reduced as compared with the case of mounting on one side of the board. And when mounting the first and second mounting components on each of the both surfaces of the substrate, the respective centroids of the first and second mounting components are located on the same normal line of the substrate mounting surface (one surface, the other surface), The first mounting area of the first mounting component and the second mounting area of the second mounting component overlap relatively large in a plane orthogonal to the normal direction, and the method of manufacturing such a circuit board includes the normal line. The mounting area when viewed in plan from the direction can be made relatively small. In particular, when the first mounting surface of the first mounting component and the second mounting surface of the second mounting component have the same shape, the mounting area when viewed in plan from the normal direction is minimized.

  And since the manufacturing method of such a circuit board mounts a 1st and 2nd mounting component on a board | substrate using the 1st and 2nd connection member which has a core member formed with the elastic material, a board | substrate, 1st When the thermal expansion coefficients of the mounting component and the second mounting component are different, even if the stress is generated due to the temperature change and the difference of the thermal expansion coefficient, the core member of the elastic material in the first and second connection members Absorbed and relaxed. Further, in such a circuit board mounting method, since the first and second mounting components are mounted on the both surfaces of the board with the respective centers of gravity superimposed on each other, there are a plurality of the first and second connection members. In addition, the stress can be applied substantially evenly, and the stress concentration can be alleviated. In particular, when the first mounting surface of the first mounting component and the second mounting surface of the second mounting component have the same shape, and each of the first and second connection members is arranged symmetrically with the center of gravity as the center of symmetry. Can be loaded evenly and stress concentration can be minimized. Thus, in this circuit board mounting method, the stress can be absorbed by the core members of the first and second connection members, and the stress concentration can be reduced. Generation | occurrence | production of the crack (crack) which may arise in each connection part (joint part) of the 1st and 2nd connection member with respect to components can be suppressed.

  Therefore, such a method for manufacturing a circuit board can reduce the mounting area without impairing the connection reliability of the connection part (joint part) by heat cycle.

  The circuit board and the circuit board manufacturing method according to the present invention can reduce the mounting area without impairing the connection reliability of the connection part (joint part) by heat cycle.

It is sectional drawing which shows the structure of the circuit board in 1st Embodiment. It is a disassembled perspective view of the circuit board in 1st Embodiment. It is sectional drawing which shows the structure of the connection member in the circuit board of 1st Embodiment. It is a figure for demonstrating the manufacturing process of the circuit board in 1st Embodiment. It is sectional drawing which shows the structure of the circuit board in 2nd Embodiment.

  Hereinafter, an embodiment according to the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted suitably. In this specification, when referring generically, it shows with the reference symbol which abbreviate | omitted the suffix, and when referring to an individual structure, it shows with the reference symbol which attached the suffix.

(First embodiment)
FIG. 1 is a cross-sectional view showing a configuration of a circuit board in the first embodiment. FIG. 2 is an exploded perspective view of the circuit board in the first embodiment. FIG. 3 is a cross-sectional view illustrating a configuration of a connection member in the circuit board according to the first embodiment.

  As shown in FIGS. 1 and 2, the circuit board Ca in the first embodiment includes a board 1, a mounting component 2, and one or a plurality of spherical connection members 3.

  The substrate 1 is, for example, a plate-like or film-like component used for fixing and wiring an electronic component. The substrate 1 is, for example, a glass composite substrate, a glass epoxy substrate, a polyimide flexible substrate, or the like. In order to perform wiring, a wiring pattern and electrode pads may be formed on the surface of the substrate 1, and vias such as through-hold vias, blind vias, and buried vias may be formed therein. The substrate 1 may be such a printed wiring board.

  The mounting component 2 is a component including one or a plurality of electronic components. The electronic components are, for example, passive components such as resistance elements and capacitors, active components such as diodes and transistors, and IC chips (including LSI chips) in which these passive components and active components are integrated. More specifically, the mounting component 2 is a package component in which one or a plurality of members on which such electronic components are mounted are packaged with, for example, resin or ceramic. In the present embodiment, for example, the mounting component 2 further includes a spherical connection member 3, and a ball grid array (Ball Grid Array) semiconductor in which a member (sub-board) on which a semiconductor chip such as an IC chip is mounted is packaged. Package parts.

  The ball grid array is a packaging method suitable for surface mounting technology. As shown in FIG. 2, one or a plurality of electrode lands 21 facing the outside from the resin or ceramic package 22 are provided on the plane of the semiconductor package component. Provided. This electric next land 21 is for connecting the spherical connecting member 3.

  In the present embodiment, the mounting component 2 is mounted on one surface of the substrate 1 and mounted on the first mounting component 2-1 including one or more electronic components and the other surface facing the one surface of the substrate 1. And a second mounting component 2-2 including one or more electronic components.

  The spherical connection member 3 is a member used for mounting the mounting component 2 on the substrate 1. For example, as shown in FIG. 3, the spherical connecting member 3 includes a spherical core member 31 formed of an elastic material and a conductive layer 32 formed of a conductive material and covering the surface of the core member 31. Yes. Examples of such a spherical connecting member 3 include Micropearl SOL (manufactured by Sekisui Chemical Co., Ltd.). The micropearl SOL includes a resin core formed from a divinylbenzene crosslinked polymer, a copper (Cu) first conductive metal layer covering the surface of the resin core, and a surface of the first conductive metal layer. And a second conductive metal layer of solder to be covered.

  In the present embodiment, since the first and second mounting components 2-1 and 2-2 are mounted on both surfaces of the substrate 1, the spherical connecting member 3 is used for mounting the first mounting component 2-1 on the substrate 1. A plurality of first spherical connecting members 3-1 (eight first spherical connecting members 3-11 to 3-18 in the example shown in FIG. 1 and FIG. 2) and a second mounting component 2-2. It comprises a plurality of second spherical connecting members 3-2 (3-21 to 3-28) used for mounting on the substrate 1.

  In the present embodiment, as shown in FIG. 2, the substrate 1 is provided with a first electrode pad 11-1 for connecting the first spherical connecting member 3-1, on one surface. A second electrode pad 11-2 (not shown) for connecting the two spherical connecting members 3-2 is formed on the other surface. The first electrode pads 11-1 are formed at the positions corresponding to the positions of the first spherical connection members 3-1, in the number corresponding to the number, and in the example shown in FIG. -11 to 11-18 are formed. Similarly, the second electrode pads 11-2 are formed at the positions corresponding to the positions of the second spherical connecting members 3-2 in the number corresponding to the number, and in the example shown in FIG. Electrode pads 11-21 to 11-28 (not shown) are formed. The first and second electrode pads 11-1 and 11-2 may be connected with the above-described wiring patterns and vias for wiring.

  For this reason, the first mounting component 2-1 is mounted on one surface of the substrate 1 via the plurality of first electrode pads 11-11 to 11-18 and the plurality of first spherical connection members 3-11 to 3-18. The second mounting component 2-2 is mounted on the other surface of the substrate 1 via a plurality of second electrode pads 11-21 to 11-28 and a plurality of second spherical connection members 3-21 to 3-28. Is done.

  And in the circuit board Ca in this embodiment, as shown in FIG. 2, the 1st and 2nd mounting components 2-1 and 2-2 are the gravity center W1 of the 1st mounting components 2-1, and the 2nd mounting components 2. -2 center of gravity W2 is mounted so as to be located on the same normal line NX of the one surface and the other surface of the substrate 1. That is, when the circuit board Ca is viewed in plan, the position of the center of gravity W1 of the first mounting component 2-1 overlaps the position of the center of gravity W2 of the second mounting component 2-2.

  In the circuit board Ca of the first embodiment, the first and second mounting components 2-1 and 2-2 are mounted on both surfaces of the substrate 1, so that the mounting area is larger than when mounting on one surface of the substrate 1. Can be reduced. When the first and second mounting components 2-1 and 2-2 are mounted on both surfaces of the substrate 1, the centers of gravity W1 and W2 of the first and second mounting components 2-1 and 2-2 are the substrate. Since it is located on the same normal line NX of the mounting surface (one surface, the other surface), the first mounting area of the first mounting component 2-1 and the second mounting area of the second mounting component 2-2 are the above-mentioned method. Such a circuit board can be relatively reduced in mounting area when viewed in plan from the normal direction. In particular, when the first mounting surface of the first mounting component 2-1 and the second mounting surface of the second mounting component 2-2 have the same shape, the mounting area in plan view from the normal direction is Minimal.

  And since the circuit board Ca of such 1st Embodiment is equipped with the 1st and 2nd spherical connection members 3-1 and 3-2 with the core member 31 formed with the elastic material, the board | substrate 1, 1st When the thermal expansion coefficients of the mounting component 2-1 and the second mounting component 2-2 are different, even if the stress is generated due to the temperature change and the difference of the thermal expansion coefficient, the first and second spherical connecting members 3-1 and 3-2 are absorbed and relaxed by the core member 31 of the elastic material. Further, the circuit board Ca according to the first embodiment mounts the first and second mounting components 2-1 and 2-2 on the both surfaces of the board 1 so that the center of gravity W 1 and W 2 overlap each other. When there are a plurality of each of the first and second connection members 3-1 and 3-2, the load can be substantially evenly distributed, and the stress concentration can be reduced. In particular, the first mounting surface of the first mounting component 3-1 and the second mounting surface of the second mounting component 3-2 have the same shape, and the first and second connection members 3-1 and 3-2 are respectively When the gravity centers W1 and W2 are arranged symmetrically with respect to the center of symmetry, the burden can be applied most evenly and the stress concentration can be minimized. Thus, the circuit board Ca of the first embodiment can absorb the stress with the core members of the first and second connection members 3-1 and 3-2, and can further reduce the stress concentration. Generation of cracks that can occur in the connection portions (joint portions) of the first and second connection members 3-1 and 3-2 with respect to the substrate 1 and the first and second mounting components 2-1 and 2-2. Can be suppressed.

  Therefore, the circuit board Ca of the first embodiment can reduce the mounting area without impairing the connection reliability of the connection part (joint part) by heat cycle.

  From the above viewpoint, in the circuit board Ca of the first embodiment, preferably, the first mounting surface of the first mounting component 2-1 and the second mounting surface of the second mounting component 2-2 have the same shape. is there.

  Such a circuit board Ca in the first embodiment can be manufactured by the following steps. That is, the circuit board Ca in the first embodiment includes a first mounting step of mounting the first mounting component 2-1 on the one surface of the substrate 1 via the first spherical connection member 3-1, and the one of the board 1 described above. It can manufacture by implementing the 2nd mounting process which mounts the 2nd mounting component 2-2 via the 2nd spherical connection member 3-2 on the other surface facing a direction. Here, in at least one of the first mounting step and the second mounting step, the first and second mounting components 2-1 and 2-2 have the second center of gravity W 1 of the first mounting component 2-1 and the second mounting step 2-1. It implements so that the gravity center W2 of the mounting component 2-2 may be located on the same normal line NX of the said one surface and the said other surface in the board | substrate 1. FIG.

  FIG. 4 is a diagram for explaining a circuit board manufacturing process according to the first embodiment. More specifically, in FIG. 4, first, each of the first spherical connection members 3-11 to 3-18 is placed on each of the first electrode lands 21-11 to 21-18 in the first mounting component 2-1. The first spherical connecting members 3-11 to 3-18 are temporarily fixed to the first mounting component 21-1 with a solder paste so as to be arranged (FIG. 4A).

  Next, the first spherical connection members 3-11 to 3-18 are arranged on the first electrode pads 11-11 to 11-18 on the substrate 1, respectively. A first mounting component 2-1 having 11 to 18-18 is temporarily fixed on one surface (front surface) of the substrate 1 with a solder paste. And it solders by what is called a reflow system. That is, first, preheating is performed, followed by main heating, and cooling. As a result, the solder paste is melted by heat and solidified by cooling (FIG. 4B). As a result, the first mounting component 2-1 is mounted on one surface (main surface) of the substrate 1 via the first spherical connecting member 3-1.

  Subsequently, similarly, the second spherical connection members 3-21 to 3-28 are arranged on the second electrode lands 21-21 to 21-28 in the second mounting component 2-2, respectively. The second spherical connection members 3-21 to 3-28 are temporarily fastened to the second mounting component 21-2 with solder paste (FIG. 4C).

  Next, the second spherical connection members 3-21 to 3-28 are arranged on the second electrode pads 11-21 to 11-28 on the substrate 1, respectively. The second mounting component 2-2 including 21 to 28 is temporarily fixed to the other surface (back surface) of the substrate 1 with a solder paste. Here, the substrate 1 is arranged such that the center of gravity W1 of the first mounting component 2-1 and the center of gravity W2 of the first mounting component 2-2 are located on the same normal line NX of one surface (the other surface) of the substrate 1. At least one of the positions of the electrode pads 11-11 to 11-18 on one side and the positions of the electrode pads 11-21 to 11-28 on the other side is adjusted and disposed. And it solders by what is called a reflow system. That is, first, preheating is performed, followed by main heating, and cooling. As a result, the solder paste is melted by heat and solidified by cooling (FIG. 4D). As a result, the second mounting component 2-2 is mounted on the other surface (back surface) of the substrate 1 via the second spherical connecting member 3-2.

  In the above description, in the temporary fixing step (FIG. 4C) of the second spherical connection members 3-21 to 3-28 to the second mounting component 2-2, the first mounting component 2-1 is attached to the substrate 1. Although it implemented after mounting on the surface, it is the same as the temporary attachment process (FIG. 4 (A)) to the 1st mounting components 2-1 of the 1st spherical connection members 3-11 to 3-18, or its temporary attachment It may be carried out after the step (FIG. 4A).

  In the above description, the first and second spherical connection members 3-1 and 3-2 are temporarily fixed to the packaged first and second mounting components 2-1 and 2-2. In the process of packaging the mounting component 2-1, the first spherical connecting member 3-1 may be packaged together with the first mounting component 2-1, and the second mounting component 2-2 is packaged. In the process, the second spherical connecting member 3-2 may be packaged together with the second mounting component 2-1.

  Through these steps, the first and second mounting components 2-1 and 2-2 are mounted on both surfaces of the substrate 1 via the first and second spherical connection members 3-1 and 3-2, respectively. The circuit board Ca according to the first embodiment mounted on is manufactured.

  Next, another embodiment will be described.

(Second Embodiment)
FIG. 5 is a cross-sectional view showing a configuration of a circuit board in the second embodiment. As shown in FIG. 5, the circuit board Cb in the second embodiment further includes a reinforcing member 5 with respect to the circuit board Ca in the first embodiment. That is, the circuit board Cb in the second embodiment includes the board 1, the first and second mounting components 2-1, 2-2, the first and second spherical connecting members 3-1, 3-2, and the reinforcement. And a member 5. The board 1, the first and second mounting components 2-1, 2-2, and the first and second spherical connecting members 3-1, 3-2 in the circuit board Cb of the second embodiment are respectively the first embodiment. Since it is the same as the substrate 1, the first and second mounting components 2-1, 2-2, and the first and second spherical connecting members 3-1, 3-2 in the circuit board Ca of the embodiment, the description thereof is omitted. .

  The reinforcing member 5 is a member that is provided around the mounting component 2 and between the mounting component 2 and the substrate 1 and reinforces the connection between the mounting component 2 and the substrate 1. The reinforcing member 5 is a so-called side fill. The reinforcing member 5 is made of, for example, a resin material such as an epoxy resin. In the example shown in FIG. 5, the reinforcing member 5 is a first reinforcing member 5-1 provided between the first mounting component 2-1 and the substrate 1 around the first periphery of the first mounting component 2-1. And a second reinforcing member 5-2 provided between the second mounting component 2-2 and the substrate 1 around the second mounting component 2-2.

  The reinforcing member 5 may be one of the first reinforcing member 5-1 and the second reinforcing member 5-2. The first reinforcing member 5-1 may be a part of the first periphery instead of the entire circumference of the first mounting component 2-1, and the first reinforcing member 5-1 is the first mounting component 2- A plurality of the first peripherals may be provided at a predetermined interval in the circumferential direction. Similarly, the second reinforcing member 5-2 may be a part of the second periphery instead of the entire circumference of the second mounting component 2-2, and the second reinforcing member 5-2 is the second mounting member. A plurality of parts 2-2 may be provided around the first periphery of the component 2-2 at predetermined intervals in the circumferential direction.

  Usually, the spherical connecting member 3 is small, and in particular for BGA, it is very small with a diameter of φ0.2 to 0.5 mm. For this reason, since the connection strength of the mounting component mounted on the substrate 1 via the spherical connection member 3 is relatively weak, for example, when stress is applied from the outside such as impact or bending, the mounting component is dropped or the spherical connection member 3 is removed. In some cases, cracks and the like may occur at the joints to the substrate 1 and the mounting component 2 in FIG.

  Since the circuit board Cb in the second embodiment further includes the reinforcing member 5, stress concentration on the spherical connection member 3 is reduced by bearing external stress on the entire circuit board Cb against such external stress. be able to. For this reason, the circuit board Cb in 2nd Embodiment can improve the reliability of the connection of the junction part with respect to the board | substrate 1 and the mounting components 2 in the spherical connection member 3 more.

  In order to express the present invention, the present invention has been properly and fully described through the embodiments with reference to the drawings. However, those skilled in the art can easily change and / or improve the above-described embodiments. It should be recognized that this is possible. Therefore, unless the modifications or improvements implemented by those skilled in the art are at a level that departs from the scope of the claims recited in the claims, the modifications or improvements are not covered by the claims. To be construed as inclusive.

Ca, Cb Circuit board 1 Board 2 Mounting component 3 Spherical connection member 5 Reinforcing member

Claims (5)

A substrate,
A first mounting component mounted on one surface of the substrate via a first connection member and including one or more electronic components;
A second mounting component including one or more electronic components mounted on the other surface of the substrate facing the one surface via a second connection member;
The first and second mounting components are mounted such that the center of gravity of the first mounting component and the center of gravity of the second mounting component are located on the same normal line of the one surface or the other surface of the substrate,
Each of the first and second connecting members includes a core member formed of an elastic material and a conductive layer formed of a conductive material and covering a surface of the core member. A first periphery of the first mounting component or a part of the first periphery, provided between the first mounting component and the substrate, for reinforcing the connection between the first mounting component and the substrate. 1 reinforcing member and a second periphery of the second mounting component or a part of the second periphery and provided between the second mounting component and the substrate; and the second mounting component and the substrate The circuit board according to claim 1, further comprising at least one of second reinforcing members that reinforce the connection. 3. The circuit board according to claim 1, wherein the mounting surface of the first mounting component and the mounting surface of the second mounting component have the same shape. The first mounting component is a package component of a ball grid array having the first connection member,
The circuit board according to claim 1, wherein the second mounting component is a ball grid array package component having the second connection member. A first mounting step of mounting a first mounting component including one or more electronic components on one surface of the substrate via a first connection member;
A second mounting step of mounting a second mounting component including one or a plurality of electronic components on the other surface facing the one surface of the substrate via a second connection member;
The first and second mounting components are mounted such that the center of gravity of the first mounting component and the center of gravity of the second mounting component are located on the same normal line of the one surface or the other surface of the substrate,
Each of the first and second connection members includes a core member formed of an elastic material, and a conductive layer formed of a conductive material and covering the surface of the core member. Production method.

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