JP2011014809A - Stack type circuit board and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stack type circuit board in which a mounting area is small, and a method of manufacturing the same.SOLUTION: A circuit board comprising a board material and a conductive pattern is divided along a bending part, as a border, where a part or the whole of the board material is removed, folded using the conductive pattern of the folding part so that divided circuit boards face each other, and then fixed by a fixing means so that the distance between the circuit boards folded to be stacked becomes constant.

Description

  The present invention relates to a circuit board for mounting a circuit component such as a semiconductor device, and more particularly to a stacked circuit board in which a plurality of circuit boards are stacked in order to reduce the mounting area.

  Along with the development of technology in recent years, circuit boards on which circuit components such as semiconductor devices are mounted are often used in electrical equipment for miniaturization. These circuit boards are configured as modules on which various components are mounted, so that electric devices are further miniaturized. For example, an in-vehicle electronic control unit (Electronic Control Unit; hereinafter abbreviated as “ECU”) is not configured so that the ECU alone is stored in a part of the body of the car, but is integrated with a motor or an actuator. The module structure is changing. The board in such a configuration is required to be mounted with higher density while an element that switches a large current and a microcomputer coexist. Further, for example, the camera module is further miniaturized by integrally mounting an imaging lens and a CMOS (Complementary Metal Oxide Semiconductor) light receiving element as an imaging element.

  As described above, the circuit board has a module configuration in which not only circuit components but also other components are integrated and mounted, and the whole electrical device is reduced in size by being mounted with higher density. Therefore, in recent years, a circuit board suitable for higher density mounting and having a small mounting area and a manufacturing method thereof are desired.

  For example, Patent Document 1 (Republished 1996-10326) is a prior art document for reducing the cost and size of the entire electrical equipment. In Patent Document 1, the substrate material is partially deleted along the crease, the substrate divided along the crease formed from the conductor pattern is bent, and the substrate material is bonded. The bent and bonded substrate has a reduced area by being bent, and a continuous conductor pattern is formed on both sides of the substrate material beyond the fold without providing a through hole. Using this bent conductor pattern, it is possible to connect to another substrate.

  Further, in Patent Document 2 (Japanese Patent Laid-Open No. 59-220989), a substrate is attached to the back surface of a copper foil for forming an electric circuit on the surface with a gap, circuit components are mounted on the surface of the copper foil, A technique for folding a foil to overlap substrates is disclosed. In Patent Document 3 (Japanese Patent Laid-Open No. 61-208890), two slits are provided in a bent portion of a metal substrate having an insulating film, a conductive path, and a circuit element on the surface, and the conductive path and the circuit element face each other. Therefore, a hybrid integrated circuit is disclosed in which a slit is bent and a circuit element is surrounded by a metal substrate. In these patent documents, the mounting area can be reduced by bending the substrate.

Republished 1996-10326 JP 59-220989 A JP-A-61-208890

  As described above, in order to reduce the mounting area, there is a method of bending the circuit board. However, Patent Document 1 is single-sided mounting, in which an end portion of a substrate is bent and an opposing substrate is bonded, and downsizing of the mounting area is limited to a connection region at the end portion of the substrate. Patent Document 2 is for attaching a substrate to the back surface of a copper foil, and Patent Document 3 is for enclosing circuit elements with a metal substrate, and is not a general technique, and is generally not applicable to a wide field. There is.

  Furthermore, there is a method of using a flexible substrate as a technique for bending the substrate to reduce the size. In this case, the flexible substrate is weak and requires a member that reinforces it, and there are limited parts that can be mounted due to problems such as warpage and poor heat resistance. Difficult to apply. Further, there is a configuration in which an organic substrate and a flexible substrate can be folded and folded, such as a rigid flexible substrate, but there is a problem that the construction method becomes complicated and expensive.

  The present invention has been made to solve the above-described problems, and in particular, provides a multilayer circuit board having a small mounting area and a method for manufacturing the same.

  According to one aspect of the present invention, a circuit board having a substrate material and a conductive pattern is divided with a bent portion from which part or all of the substrate material is removed as a boundary, and the divided circuit boards face each other. In this way, a laminated circuit board is obtained which is fixed by a fixing means so that the distance between the divided circuit boards which are bent by using the conductive pattern of the bent portion and bent is fixed.

  According to another aspect of the present invention, the circuit board includes a substrate material and a conductive pattern, and the circuit board is divided by removing a part or all of the substrate material in the bent portion, and the conductive pattern of the bent portion. Can be used to bend the circuit board, and to obtain a method of manufacturing a laminated circuit board that is fixed by a fixing means so that the interval between the divided circuit boards that are folded so as to face each other is constant. .

  According to the present invention, the circuit board is bent so as to face each other at the bent portion, and the circuit board is bent and fixed so that the distance between the circuit boards is constant. Since a plurality of circuit boards are opposed to each other and stacked, a plurality of circuit boards can be arranged in the installation area of one circuit board, and the board mounting area can be reduced.

It is sectional drawing which shows the manufacturing method of the laminated circuit board in Example 1 in order of a process. 3 is a cross-sectional view illustrating a bent portion of the multilayer circuit board in Example 1. FIG. 6 is a cross-sectional view of a multilayer circuit board in Example 2. FIG. 10 is a cross-sectional view illustrating a bent portion of a multilayer circuit board in Example 3. FIG. 6 is a cross-sectional view of a multilayer circuit board in Example 3. FIG.

(First embodiment)
A first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a method of manufacturing a multilayer circuit board in this embodiment in the order of steps. FIG. 2 is a cross-sectional view showing details of the bent portion of the multilayer circuit board. The substrate material 1 of the circuit board shown in FIG. 1 is a rigid substrate material made of an insulating organic substrate material such as FR-4. However, the present invention is not particularly limited to the material of the substrate, and can be applied to substrates made of various substrate materials.

  In the circuit board shown in FIG. 1A, circuit components 2 are mounted on both surfaces of a substrate material 1 and connected by a copper foil pattern 3 to form an electric circuit. Circuit components are arranged on the left and right sides of the board, respectively, with the central part of the circuit board as a boundary. The circuit divided into right and left can be variously configured depending on the product. For example, the circuit is divided into circuit blocks that are easily separated as analog blocks and digital circuits.

  Next, as shown in FIG. 1B, the central portion of the substrate material 1 is removed leaving the copper foil pattern 3. A region where the substrate material is removed becomes a bent portion 4. The bent portion 4 is formed only of the copper foil pattern 3 from which the substrate material 1 is removed. In this way, the board is divided into left and right circuit boards with the bent portion 4 as a boundary. Further, the divided left and right circuit boards are bent through the bent portion 4 so that the left and right boards face each other. In the present invention, the left and right circuit boards are connected by the copper foil pattern 3 by scraping the board material, but the regions where the left and right circuit components are mounted are represented as divided circuit boards, respectively. . Accordingly, the original one circuit board is divided into two small left and right circuit boards with the bent portion 4 as a boundary, and the left and right divided circuit boards each become one new circuit board.

  As shown in FIG. 1 (C), the copper foil pattern 3 of the bent portion 4 is bent so that the board surfaces of the divided circuit boards face each other in the vertical direction of the drawing. In the following description, as shown in FIG. 1C, arranging the substrate surfaces to face each other means that the circuit substrates are made to face each other or the circuit substrates are stacked. Further, as shown in FIG. 1D, the upper and lower substrates are fixed with screws 5 so that the opposing substrates are at a constant interval. Further, the copper foil pattern 3 is covered with a silicon-based resin 6 in order to protect the exposed copper foil pattern 3. In this way, a laminated circuit board is obtained in which the divided circuit boards are stacked so as to face each other. In the figure, since the bent portion is provided in the central portion of the first circuit board, the circuit board is divided into two circuit boards each having an approximately half area. Therefore, the mounting area is halved. However, the area ratio of the circuit board to be divided is not particularly limited, and can be set to an arbitrary area ratio.

  In FIG. 1D, the screw 5 is used for fixing, but the fixing method using the screw 5 is an example, and the fixing method is not particularly limited. Any method may be used. In addition, the width of the board to be removed as the bent portion 4 is determined in consideration of maintaining an appropriate distance so that circuit components of the upper and lower boards facing each other do not come into contact with each other when fixed.

  Furthermore, with reference to FIG. 2, a bending part is demonstrated. FIG. 2 shows a cross-sectional view of the circuit board for explaining the bent portion 4. Copper foil patterns 3 are wired on both surfaces of the substrate material 1 via a resin 7 for pattern adhesion. The pattern bonding resin 7 is not applied in advance between the substrate material 1 and the copper foil pattern 3 of the bent portion 4 where the substrate material 1 is removed. Further, a cut 8 is formed at a location where the substrate material 1 is removed. The substrate material is removed along the notches 8. Since there is no resin for pattern adhesion between the substrate material and the copper foil pattern removed at that time, the substrate material can be easily removed leaving the copper foil pattern. In the embodiment, a double-sided board is taken as an example, but a multilayer board may be used. In this case, the copper foil pattern to be left for the convenience of the configuration may be a structure in which the copper foil pattern for the inner layer is left, even if it is not the surface copper foil pattern.

  In this embodiment, when circuit components are mounted on the board, it is a single circuit board and can be mounted in exactly the same manner as conventional surface mounting. After completing the component mounting, the board material at the bent portion is removed along the notch of the board material, and the circuit board is divided. The copper foil pattern in the bent portion is bent and laminated so that the divided circuit boards face each other as upper and lower substrates. Further, the opposing substrates are fixed at a constant interval, and the copper foil pattern of the bent portion is covered with a silicon resin. By making the plurality of substrates thus divided face each other and stacking in the vertical and vertical directions, it becomes possible to install a plurality of substrates on one substrate area, and the mounting area can be reduced.

(Second embodiment)
A second embodiment of the present invention will be described in detail with reference to the drawings. The present embodiment is an embodiment in which the copper foil pattern is folded a plurality of times, and FIG. 3 shows a cross-sectional view of the multilayer circuit board in the second embodiment.

  The multilayer circuit board shown in FIG. 3 includes two bent portions. In the drawing, the lower and middle substrates are bent at the first bent portion made of the copper foil pattern 3 and the silicon-based resin 6 as in FIG. Further, the middle and upper substrates are bent at a second bent portion made of the copper foil pattern 3-2 and the silicon-based resin 6-2. In this way, a laminated circuit board is obtained in which a plurality of circuit boards are laminated in order in the vertical and vertical directions of the figure. The configurations of the lower and middle substrates, the middle and upper substrates, and the manufacturing method thereof are the same as in the first embodiment, and the description thereof is omitted.

  The lower, middle, and upper stage circuit boards each mounting the circuit component 2 are bent by the copper foil patterns of the two bent portions to form a three-dimensional three-dimensional laminated circuit board. In FIG. 3, three divided circuit boards are stacked by bending the circuit board at two folding portions. By stacking in this way, it becomes possible to install three circuit boards in the installation area of one circuit board, and the installation surface area of the board can be reduced to about 1/3. In FIG. 3, the respective circuit boards facing each other are shown as the same board area, but are not limited to the same board area, and can be set to any board area. In this case, a fixing position is provided according to each substrate area. In addition, the distance to the bent portion is not particularly limited, and each appropriate part of the circuit board on each of the upper and lower circuit boards facing each other when fixed is secured so as not to contact each other. It can be a distance.

  As described above, when N (N is a natural number) bent portions of the copper foil pattern are provided, the (N + 1) circuit boards can be three-dimensionally stacked so that the circuit boards face each other. Therefore, it becomes possible to install (N + 1) substrates on one substrate area, and the mounting area can be further reduced.

(Third embodiment)
A third embodiment of the present invention will be described in detail with reference to the drawings. Compared with the first embodiment, this embodiment is an embodiment in which a portion of the substrate material in the bent portion is not removed, but a part thereof is left thin. FIG. 4 is a cross-sectional view illustrating a bent portion of the circuit board. FIG. 5 shows a cross-sectional view of the multilayer circuit board.

  Copper foil patterns 3 are wired on both surfaces of the substrate material 1 of FIG. The bent portion 4 on the upper surface side of the circuit board is provided with a copper foil pattern 3 and a pattern bonding resin 7. On the other hand, neither the copper foil pattern 3 nor the pattern bonding resin 7 is provided in the bent portion 4 on the lower surface side of the substrate. The substrate material is scraped off from the lower side of the circuit board, and the recess 9 is formed so as to leave a little thickness of the substrate material 1 on the copper foil pattern 3 side. The substrate material of the thin part in which this recessed part 9 was formed is set as the substrate material 1A. The thickness of the substrate material 1A is a thickness at which the copper foil pattern and the substrate material can be bent. In this embodiment, since the substrate material is left thin on the copper foil pattern 3 side of the bent portion, the bent portion on the upper surface side of the substrate material 1 is provided with a pattern bonding resin 7.

  Next, the copper foil pattern 3 of the bent portion 4 and the thin substrate material 1A are bent so that the circuit boards face each other vertically. Further, the upper and lower circuit boards facing each other are fixed with screws 5 so as to be at a constant interval. Further, in order to protect the copper foil pattern 3, the copper foil pattern 3 is covered with a silicon-based resin 6. Here, since the copper foil pattern 3 is reinforced with the thin substrate material 1 </ b> A, it is possible to omit covering with the silicon-based resin 6. In this embodiment, the bent portion 4 is formed of the copper foil pattern 3 and the thin substrate material 1A, and the substrate material 1 and the thin substrate material 1A are continuous. However, since the left and right circuit boards are bent so as to face each other through the bent portion 4, first, as in the embodiment, it is divided into two left and right circuit boards with the bent portion 4 as a boundary. These circuit boards are respectively divided circuit boards. That is, each circuit board that is bent by the bending portion 4 and arranged to face each other is defined as one circuit board.

  Also in the present embodiment, a laminated circuit board is obtained in which the board is bent and two circuit boards are three-dimensionally laminated so as to face each other. In this way, two substrates can be arranged in one substrate installation area, and the substrate mounting area can be reduced.

  In the multilayer circuit board of the present invention, after the circuit components are mounted on the board, the board material is removed with the copper foil pattern remaining at an arbitrary position on the board. As a result, the two substrates are connected via the copper foil pattern. Thereafter, the copper foil pattern is bent and fixed so that the two circuit boards face each other. The substrates are bent so that the two substrates face each other. In this manner, two substrates can be arranged in the installation area of one substrate, and the substrate mounting area can be reduced.

  In the method of the present invention, it is possible to bend like a flexible substrate after mounting a component by using the above-described configuration while using a substrate of a general material. The strength can be adjusted by changing the substrate material to be used according to the application, and the current capacity flowing can be adjusted by changing the width and thickness of the copper foil pattern.

  The first effect obtained from the present invention is that the board can be folded and the mounting area can be reduced regardless of the material of the board. Further, the second effect is that the two substrates are connected by the copper foil pattern by bending with a copper foil pattern, so that a connection process such as soldering is unnecessary, and an extra component such as a connector. Connection reliability is extremely high. The third effect is that unlike a product using a flexible substrate, the material of the substrate, the thickness of the copper foil pattern, etc. can be freely changed. It is. The fourth effect is that since the component configuration of the substrate is the same as that of a substrate that is not bent, the cost can be reduced even when compared with a configuration using a flexible substrate.

  Although the present invention has been described in detail according to the embodiments, the present invention is not limited to the above-described embodiments. Various changes and modifications can be made to the configuration and details of the present invention within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Board | substrate material 2 Circuit components 3 Copper foil pattern 4 Bending part 5 Screw 6 Silicone resin 7 Resin for pattern adhesion 8 Notch 9 Recessed part

Claims (13)

  A circuit board provided with a substrate material and a conductive pattern is divided by using a bent portion from which part or all of the substrate material is removed as a boundary, and the conductive pattern of the bent portion is used so that the divided circuit boards face each other. A laminated circuit board, wherein the laminated circuit board is fixed by a fixing means so that a distance between the divided circuit boards that are laminated by being bent is fixed.   2. The laminated circuit board according to claim 1, wherein a resin for pattern adhesion is not applied between the conductive pattern and the substrate material in the bent portion.   The N-folded portion (N is a natural number) is provided, and (N + 1) divided circuit boards are sequentially stacked in a vertical direction so as to face each other. Multilayer circuit board.   The multilayer circuit board according to claim 1, wherein the conductive pattern bent at the bent portion is covered with a silicon resin.   The laminated circuit board according to any one of claims 1 to 4, wherein the laminated circuit boards are fixed so as to face each other at regular intervals using screws as the fixing means. .   The laminated circuit board according to claim 1, wherein the conductive pattern is formed of a copper foil.   The laminated circuit board according to claim 1, wherein the substrate material is an insulating organic substrate material.   The circuit board includes a substrate material and a conductive pattern. The circuit board is divided by removing a part or all of the substrate material at a bent portion, and the circuit board is bent and bent using the conductive pattern of the bent portion. A method of manufacturing a laminated circuit board, comprising: fixing means so that a distance between the divided circuit boards stacked so as to face each other is fixed.   9. The method according to claim 8, wherein when part or all of the substrate material is removed from the bent portion, a cut is provided in the substrate material of the bent portion, and part or all of the substrate material is removed along the cut. The manufacturing method of the laminated circuit board of description.   The method for manufacturing a multilayer circuit board according to claim 8 or 9, wherein the conductive pattern bent at the bent portion is covered with a silicon resin.   11. The method for manufacturing a multilayer circuit board according to claim 8, wherein the fixing means is a screw.   The method of manufacturing a multilayer circuit board according to claim 8, wherein the conductive pattern is formed of a copper foil.   The method for manufacturing a multilayer circuit board according to claim 8, wherein the substrate material is made of an organic substrate material having an insulating property.

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