JP2008311553A - Method for manufacturing compound multilayer printed-wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a compound multilayer printed-wiring board capable of maintaining positional accuracy for coping with downsizing. <P>SOLUTION: The method for manufacturing the compound multilayer printed-wiring board having: one layer 10 comprising only a flexible printed-wiring board 5; and a multilayer 11 with both surfaces of both ends of the flexible printed-wiring board 5 laminated so as to be sandwiched by the rigid board 7 comprises a step of forming a slit 12 with its both ends opened so that the flexible printed-wiring board 5 is divided into at least two or more. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a composite multilayer printed wiring board using a flexible printed wiring board.

  Currently, printed wiring boards are mounted on various electronic devices such as mobile phones, digital cameras, and notebook computers. There are various types of printed wiring boards depending on their applications, but among these printed wiring boards, composite multilayer printed wiring boards are attracting attention in order to cope with the reduction in size, weight, and functionality of electronic devices. A composite multilayer printed wiring board is a wiring board provided with a multilayer part formed by laminating substrates and a single layer part formed by being exposed from the multilayer part. As a result, the connector space is narrowed and the mounting density is improved.

  FIG. 5 shows a side view of the composite multilayer printed wiring board 1. The circuit 3 is formed on both surfaces of the base film 2 made of a flexible resin, and the cover film 4 is laminated so as to sandwich the circuit 3 on both surfaces of the base film 2. A laminate composed of the base film 2, the circuit 3, and the cover film 4 is referred to as a flexible printed wiring board 5. A rigid substrate 7 made of a hard base material is laminated on both surfaces of both ends of the flexible printed wiring board 5 via an adhesive layer 6 formed by applying an adhesive. Circuits 3 are formed on the upper and lower surfaces of the rigid substrate 7 respectively. Thereby, the single layer part 10 which consists only of the flexible printed wiring board 5, and the multilayer part 11 which sandwiches both surfaces of the flexible printed wiring board 5 by the rigid board | substrate 7 are formed. And since the single layer part 10 becomes a cable part, it is possible to improve the mounting density and increase the functionality of the composite multilayer printed wiring board 1.

  However, the flexible printed wiring board 5 was very thin, and was distorted or displaced by a slight impact. Further, when the flexible printed wiring board 5 and the rigid board 7 are pressure-bonded, heat is applied using a press or the like, but the flexible printed wiring board 5 has a large thermal expansion coefficient and softens and becomes sticky. For this reason, the flexible printed wiring board 5 is distorted or deformed. Thereby, the dimensional stability of the flexible printed wiring board 5 is deteriorated, and there is a problem that the positional accuracy cannot be maintained when the flexible printed wiring board 5 and the rigid substrate 7 are laminated.

  By the way, the actual composite multilayer printed wiring board 1 is not manufactured one by one. A plurality of composite multilayer printed wiring boards 1 are manufactured at a time by laminating members so that the shapes in FIG. 5 are juxtaposed, and after completing all the manufacturing steps, cutting them to have the shapes in FIG. Is done. Therefore, in the following manufacturing process of a composite multilayer printed wiring board, for convenience of explanation, it is assumed that two composite multilayer printed wiring boards 1 are typically manufactured.

  FIG. 6 shows a side view of a composite multilayer printed wiring board in which ideal lamination is performed. A dotted line 13 indicates a position where a through hole for electrically connecting the flexible printed wiring board 5 and the rigid board 7 is formed. In FIG. 6, the circuit 3 is laminated in series on the dotted line 13, and the flexible printed wiring board 5 and the rigid board 7 are electrically connected by forming a through hole (not shown) at this position. Can do.

  FIG. 7 is a side view of the composite multilayer printed wiring board when the flexible printed wiring board 5 is distorted or deformed. Since the flexible printed wiring board 5 is distorted or deformed, the circuit 3 is not stacked in series on the dotted line 13 where the through hole is formed. Therefore, even if a through hole (not shown) is formed, the flexible printed wiring board 5 and the rigid board 7 cannot be electrically connected, and a composite multilayer printed wiring board cannot be manufactured.

  Therefore, in order to solve this problem, in Patent Document 1, in order to make the density of the base material constant, a groove is provided in the base material to flatten the base material in the step before pressing and pressing the base material. The method of preventing the shift | offset | difference and distortion of a base material is mentioned.

Japanese Patent Application Laid-Open No. H10-228561 discloses a method of preventing the deformation of the base material by applying the pressure in a constraining mold and fitting the base material into the mold.
JP 2005-64022 A JP-A-5-198947

  However, the method described in Patent Document 1 cannot flatten the base material but cannot prevent the base material from being deformed. Therefore, the positional accuracy of the flexible printed wiring board cannot be maintained, and the problem of the present invention that electrical connection is not achieved even if through holes are formed cannot be solved. Further, in the method described in Patent Document 2, it is possible to prevent a large deformation of the base material, but in order to prevent a minute deformation, a very precise constraining mold must be formed. Take it. In addition, as the composite multilayer printed wiring board is further reduced in size, even if it is a minute deformation, the position of the circuit of the flexible printed wiring board and the position of the circuit of the rigid board may be shifted and electrical connection may not be possible. .

  An object of this invention is to provide the manufacturing method of the composite multilayer printed wiring board which can maintain position accuracy corresponding to size reduction.

In order to achieve the above object, the present invention provides a composite multi-layer comprising a single-layer part composed only of a flexible printed wiring board and a multi-layer part laminated such that both ends of the flexible printed wiring board are sandwiched between rigid boards. In the method for manufacturing a printed wiring board,
The flexible printed wiring board is characterized in that slits having openings at both ends are formed in the flexible printed wiring board so that the flexible printed wiring board is divided into at least two parts.

  In the present invention, when the slit is formed, the lower surface of the flexible printed wiring board is bonded to the rigid substrate via an adhesive and is temporarily bonded.

  Further, the invention is characterized in that a position where the slit is formed is bonded by the rigid substrate.

  In the present invention, the position where the slit is formed does not include the circuit of the flexible printed wiring board.

  In the present invention, the flexible printed wiring board and the rigid board are formed with guide holes for alignment when they are laminated.

  According to the present invention, a pin for positioning is inserted into the guide hole when the slit is formed.

  According to the present invention, the flexible printed wiring board is divided into at least two parts by providing the flexible printed wiring board with slits opened at both ends. Therefore, even if the flexible printed wiring board is distorted, displaced, or deformed due to a minute impact or thermocompression that occurs during the manufacturing process, it can be kept within the divided size of the flexible printed wiring board. Thereby, distortion, deviation, and deformation of the flexible printed wiring board can be minimized, and the positional accuracy between the layers when manufacturing the composite multilayer printed wiring board can be maintained. Therefore, since the circuit is arranged in series at the position where the through hole is formed, the flexible printed wiring board and the rigid board can be electrically connected. Moreover, since the manufacturing method of this invention can be implemented irrespective of the size of a composite multilayer printed wiring board, it can be used even if the composite multilayer printed wiring board is miniaturized.

  According to the present invention, when the slit is formed, the lower surface of the flexible printed wiring board is bonded to the rigid substrate via the adhesive and temporarily pressed. Therefore, the flexible printed wiring board and the rigid board are fixed. Thereby, the bending and bending of the flexible printed wiring board which generate | occur | produce when providing a slit in a flexible printed wiring board can be prevented.

  According to the present invention, the position where the slit is formed is bonded by the rigid substrate. Thereby, even if a slit is provided in a flexible printed wiring board, a rigid substrate and a flexible printed wiring board can be maintained in a laminated state without being divided.

  Further, according to the present invention, the position where the slit is formed does not have the circuit of the flexible printed wiring board. Therefore, the flexible printed wiring board is formed with a slit at a position where there is no circuit. Thereby, a slit can be formed, without damaging the circuit of a flexible printed wiring board.

  According to the present invention, the flexible printed wiring board and the rigid board are formed with guide holes for alignment when they are stacked. Therefore, it is possible to perform alignment for stacking the flexible printed wiring board and the rigid board by the guide hole. Thereby, the position shift at the time of laminating | stacking a composite multilayer printed wiring board can be prevented.

  According to the present invention, when the slit is formed, the pin for positioning is inserted into the guide hole. Thereby, the position shift at the time of providing a slit in a flexible printed wiring board can be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, it is assumed that two composite multilayer printed wiring boards are typically manufactured in the manufacturing process of the composite multilayer printed wiring board.

  FIG. 1 is a side view showing a manufacturing process (1) of a composite multilayer printed wiring board in the present embodiment. The flexible printed wiring board 5 is formed by forming a circuit 3 on a base film 2 made of a flexible resin film such as polyimide or polyester using a rolled copper foil using a known photoresist or the like. It is formed by laminating a cover film 4 made of a resin film such as polyester. A rigid substrate 7 made of a non-flexible base material such as bakelite is laminated on the lower surface of the flexible printed wiring board 5 through an adhesive layer 6 made of a prepreg obtained by impregnating a glass cloth with a resin and semi-cured. At this time, the circuit 3 made of copper foil is formed on the upper and lower surfaces of the rigid substrate 7 using a known photoresist or the like. The rigid board 7 is arranged at both ends of the flexible printed wiring board 5 so that the adjacent composite multilayer printed wiring board 1 having the product shape of FIG. 5 shares one rigid board 7. Is done.

  At this time, the flexible printed wiring board 5 and the rigid substrate 7 are formed with guide holes 9 at both ends for alignment when they are laminated. Therefore, when the flexible printed wiring board 5 and the rigid substrate 7 are stacked, the alignment can be performed by stacking the guide holes 9 so as to match each other. Thereby, the position shift at the time of laminating | stacking a composite multilayer printed wiring board can be prevented.

  In addition, thermocompression bonding is performed on the product formed in the manufacturing process (1) by uniformly applying pressure to a press using a ceramic heater or the like, and the flexible printed wiring board 5 and the bottom surface of the flexible printed wiring board 5 are applied. Temporary attachment with the rigid board | substrate 7 located is performed. Therefore, the flexible printed wiring board 5 can be fixed by the rigid board 7. Thereby, the bending and bending of the flexible printed wiring board 5 which generate | occur | produce when providing the slit 12 in the flexible printed wiring board 5 by the following process (3) can be prevented.

  FIG. 2 is a side view showing the manufacturing process (2) of the composite multilayer printed wiring board in the present embodiment. A pin 8 for positioning is inserted into the guide hole 9. Thereby, position shift at the time of providing the slit 12 in the flexible printed wiring board 5 can be prevented in the subsequent step (3).

  FIG. 3 is a side view showing a manufacturing process (3) of the composite multilayer printed wiring board in the present embodiment. At a position where the circuit 3 of the flexible printed wiring board 5 is not formed, a slit 12 having a shape in which both ends are opened using a mold or the like is provided so as to divide the flexible printed wiring board 5 into at least two parts. Thereby, the slit 12 can be formed without damaging the circuit 3 of the flexible printed wiring board 5. Further, the position where the slit 12 of the flexible printed wiring board 5 is formed is bonded by the rigid substrate 7. Thereby, even if the slit 12 is provided in the flexible printed wiring board 5, the rigid substrate 7 and the flexible printed wiring board 5 can be kept in a laminated state without being divided.

  FIG. 4 is a side view showing a manufacturing process (4) of the composite multilayer printed wiring board in the present embodiment. After the slit 12 is provided in the flexible printed wiring board 5, the positioning pin 8 inserted in the guide hole 9 is removed. Then, a rigid substrate 7 is laminated on the upper surface of the flexible printed wiring board 5 via an adhesive layer 6. At this time, the circuit 3 made of copper foil is formed on the upper and lower surfaces of the rigid substrate 7 using a known photoresist or the like. The rigid board 7 is arranged at both ends of the flexible printed wiring board 5 so that the adjacent composite multilayer printed wiring board 1 having the product shape of FIG. 5 shares one rigid board 7. Is done.

  Here, since the guide hole 9 is formed in the rigid board 7, the positional accuracy of the flexible printed wiring board 5 and the rigid board 7 can be improved by stacking the guide holes 9 so as to match with each other. And the flexible printed wiring board 5 and the rigid board | substrate 7 containing the circuit 3 are cut | disconnected so that it may have the shape of FIG. 5 with respect to the product which passed through the process (1) -process (4). Thus, a composite multilayer printed wiring board having a single layer portion 10 composed only of the flexible printed wiring board 5 and a multilayer portion 11 formed by sandwiching both surfaces of both ends of the flexible printed wiring board 5 with the rigid substrate 7 is laminated. It is formed.

  According to the present invention, the flexible printed wiring board 5 is divided into at least two by providing the flexible printed wiring board 5 with the slits 12 having both ends opened. Therefore, even if distortion, a shift | offset | difference, or a deformation | transformation generate | occur | produces in the flexible printed wiring board 5 by the micro impact or thermocompression bonding etc. which occur during a manufacturing process, it can remain within the divided size of the flexible printed wiring board 5. Thereby, distortion, shift, and deformation of the flexible printed wiring board 5 can be minimized, and the positional accuracy between the layers when manufacturing the composite multilayer printed wiring board can be maintained. Accordingly, since the circuits 3 are arranged in series at the positions where the through holes are formed, the flexible printed wiring board 5 and the rigid board 7 can be electrically connected. In addition, since the production method of the present invention can be carried out regardless of the size of the composite multilayer printed wiring board, it can be used even if the composite multilayer printed wiring board is downsized.

  INDUSTRIAL APPLICABILITY The present invention can be used for a method for manufacturing a composite multilayer printed wiring board that can maintain positional accuracy corresponding to downsizing.

It is a side view which shows the manufacturing process (1) of the composite multilayer printed wiring board in this embodiment. It is a side view which shows the manufacturing process (2) of the composite multilayer printed wiring board in this embodiment. It is a side view which shows the manufacturing process (3) of the composite multilayer printed wiring board in this embodiment. It is a side view which shows the manufacturing process (4) of the composite multilayer printed wiring board in this embodiment. It is a side view of a composite multilayer printed wiring board. It is a side view which shows the manufacturing process of the conventional composite multilayer printed wiring board. It is a side view which shows the manufacturing process of the conventional composite multilayer printed wiring board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite multilayer printed wiring board 2 Base film 3 Circuit 4 Cover film 5 Flexible printed wiring board 6 Adhesive layer 7 Rigid board 8 Pin 9 Guide hole 10 One layer part 11 Multilayer part 12 Slit

Claims (6)

In a manufacturing method of a composite multilayer printed wiring board comprising a single layer portion consisting only of a flexible printed wiring board and a multilayer portion laminated so as to sandwich both surfaces of both ends of the flexible printed wiring board with a rigid substrate,
A method for producing a composite multilayer printed wiring board, comprising: forming slits in both ends of the flexible printed wiring board so that the flexible printed wiring board is divided into at least two parts.   2. The composite multilayer printed wiring board according to claim 1, wherein when the slit is formed, the lower surface of the flexible printed wiring board is bonded to the rigid substrate via an adhesive and temporarily press-bonded. Production method.   The method for manufacturing a composite multilayer printed wiring board according to claim 1, wherein the slit is formed at a position where the slit is formed by bonding with the rigid substrate.   The method for producing a composite multilayer printed wiring board according to claim 1, wherein the position where the slit is formed does not have a circuit of the flexible printed wiring board.   5. The composite multilayer print according to claim 1, wherein the flexible printed wiring board and the rigid substrate are formed with guide holes for alignment when they are laminated. A method for manufacturing a wiring board.   The method for manufacturing a composite multilayer printed wiring board according to any one of claims 1 to 5, wherein a pin for positioning is inserted into the guide hole when the slit is formed.

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