JP4292397B2 - Wiring board manufacturing method - Google Patents

Description

  The present invention relates to a method for manufacturing a wiring board incorporating an electronic component such as a chip capacitor.

  The following capacitive printed wiring board is known in which the influence of power supply noise can be reduced by giving a capacitive function to an electronic component such as an IC chip mounted on the surface of the wiring board.

  This capacitive printed wiring board has a capacitor laminated body manufactured by combining a conductive sheet on both sides of an insulating resin such as epoxy or a dielectric sheet and molding it by heating and pressing. As a typical example of the dielectric sheet, a composite material of an insulating resin such as an epoxy resin and a high dielectric constant filler is used. Further, as the conductive sheet, a metal foil, particularly a copper foil is used practically (see, for example, Patent Document 1).

In this case, the capacitance is as small as about 18 pF / mm ² , for example, and is insufficient for decoupling when applied to a high-frequency circuit.

  On the other hand, the following manufacturing method is known as a method for manufacturing a printed wiring board for the purpose of reducing loop inductance caused by wiring between an electronic component such as an IC chip mounted on a substrate surface and a power source. Yes.

  A through hole for accommodating a chip capacitor is formed in a laminated board formed by laminating prepregs. A chip capacitor in which a conductive paste is applied to the surface of the electrode is accommodated in the through hole, and an adhesive is filled between the through hole and the chip capacitor. Next, a resin film is put on both sides of the laminated plate containing the chip capacitor, and the surface is flattened by applying pressure from both sides. Then, the core substrate which consists of the accommodation layer and the connection layer which accommodated the chip capacitor is completed by heating and hardening.

  Subsequently, a non-through hole is drilled in the core substrate with a laser and a through hole for a through hole is drilled with a drill. After the desmear treatment, electroless plating is performed and a wiring pattern and via hole are formed by a known semi-ADD method. , Through holes are formed. Furthermore, a printed wiring board in which the loop inductance is reduced by forming a buildup layer by a known method is provided (see, for example, Patent Document 2).

In the above printed wiring board manufacturing method, the chip capacitor is accommodated in the through hole formed in the laminated board, that is, the accommodation hole. However, in the case of a multilayer ceramic capacitor or the like, the automatic machine accommodates the capacitor with an excessive force. Since it may be destroyed, it must be housed manually. Further, it is difficult to accommodate the thin capacitor developed for embedding and built-in in the accommodation hole, and it is necessary to provide a gap between the accommodation hole and the capacitor. Since there is a gap between the accommodation hole and the capacitor, it is necessary to interpose an adhesive between the accommodation hole and the side surface of the capacitor. However, depending on the shape of the capacitor, it may be difficult to adhere the side surface.
Japanese Patent No. 2738590 JP 2002-271032 A

  An object of the present invention is to provide a method of manufacturing a wiring board that is effective in preventing damage to an electronic component when incorporating an electronic component such as a chip capacitor.

  Another object of the present invention is to provide a method of manufacturing a wiring board suitable for obtaining a large capacitance necessary for decoupling when applied to a high frequency circuit.

The present invention relates to a method of manufacturing a wiring board incorporating an electronic component, wherein the electronic component is a capacitor having first and second electrodes, and is sealed on an insulating resin plate having a first metal layer on the other side. A step of forming at least one positioning hole penetrating the first metal layer and the insulating resin plate in a predetermined position in order to determine the position of the electronic component after stopping ; A step of placing at least one electronic component on one surface of the resin plate, and observing and storing the position of the electronic component viewed from the positioning hole by the imaging means at that time, and a location corresponding to the mounting position of the electronic component A first insulating thermosetting resin having holes or notches formed in accordance with the size of the electronic component and a second metal layer on the upper surface side capable of covering the upper surface side of the first insulating thermosetting resin a second insulating thermosetting resin having And a step of performing heat and pressure molding in combination with the insulating resin plate on which the electronic component is placed, thereby making the electronic component the insulating resin plate and the first and second insulating thermosetting resins. in addition to sealing the absence of voids, as the surface of the sealing portion becomes smooth by the positioning holes blocked by the first insulating thermosetting resin cured in the hot pressing mold process, further After the heat and pressure molding step, the first and second electrodes are formed on the first metal layer and the insulating resin plate with the positioning hole as a reference position based on the data stored in the storing step. Forming a via hole extending to one side and forming a via hole extending to the other of the first and second electrodes in the second metal layer and the cured second insulating thermosetting resin; Biaho The first metal layer and one of the first and second electrodes are connected to each other by plating, and the second metal layer and the other of the first and second electrodes are connected. And a step of performing .

  According to the present invention, a build-up wiring board can be obtained by further forming a build-up layer on the wiring board obtained by any one of the above-described manufacturing methods.

  Further, according to the present invention, by the method for manufacturing a wiring board, a plurality of wiring boards sealed with capacitors are used as inner circuit boards, and the plurality of inner circuit boards are combined with a third insulating thermosetting resin. A multilayer laminate is manufactured by heat and pressure molding, and through-holes are formed in the multilayer laminate and plating is applied to provide a large capacity sufficient for decoupling of a high frequency circuit, for example, an electrostatic capacity of about 100 μF to 100 nF. A multilayer circuit board having a capacitance can be obtained.

  In the manufacturing method according to the present invention, when sealing an electronic component such as a chip capacitor, it is only necessary to place the electronic component on an insulating resin substrate. Can be prevented.

  According to the present invention, a large capacity capacitor or a plurality of capacitors can be built in an arbitrary position, whereby a wiring board having a large capacity can be obtained.

  By manufacturing a high-frequency wiring board using a wiring board with a built-in capacitor, an IC chip such as a CPU mounted on the surface of the high-frequency wiring board and a capacitor built in the high-frequency wiring board have via holes on both sides. Since it is connected via, it can be connected at the shortest distance. As a result, instantaneous voltage supplement from the power source to the IC chip is possible, and the CPU drive voltage can be stabilized.

  In addition, because it can be a substrate with built-in electronic parts such as capacitors whose surface is flattened by heating and pressurization, even when laminating on this substrate, defects such as wiring cuts caused by unevenness Occurrence does not occur.

  By forming the power supply layer and the ground layer on the front and back sides of the wiring containing the capacitor, the wiring length is shortened and the loop inductance of the wiring is reduced.

  Furthermore, according to the present invention, a plurality of wiring boards encapsulating capacitors are used as inner layer circuit boards, and a plurality of inner layer circuit boards are combined to form a multilayer laminated board, so that the capacity is sufficient for high frequency circuit decoupling. For example, a multilayer circuit board having a capacitance of about 100 μF to 100 nF can be obtained.

Example 1
With reference to FIG. 1, a first embodiment of a method of manufacturing a wiring board according to the present invention will be described. As shown in FIG. 1A, an insulating resin plate (single side plate) 10 having a metal layer (first metal layer) 12 on one side of the insulating resin layer 11 is prepared. As a material for the insulating resin plate, for example, a material manufactured by Hitachi Chemical Co., Ltd. (trade name “679F material”) using an epoxy resin is known, but is not limited thereto. Subsequently, a through hole is formed as a positioning hole 10a in the insulating resin plate 10 (FIG. 1B). As will be described later, the positioning hole 10a is provided so that the built-in position after the built-in capacitor can be determined. When using a mounter, at least two positioning holes 10a are provided for each substrate, and three or more positioning holes 10a are provided for improving accuracy.

  Next, as illustrated in FIG. 1C, the capacitor component 20 is mounted using an adhesive resin at an arbitrary position on one side of the insulating resin layer 11. This mounting can be performed by a mounter, and at this time, the position of the capacitor component 20 viewed from the positioning hole 10a is observed and stored by an imaging means or the like, and is used for position determination when forming a via hole or the like described later. Is done. Capacitor component 20 may be either a well-known chip capacitor having electrodes formed by copper plating on the upper and lower sides, or a capacitor developed for internal use. Here, a large-capacity chip capacitor having a dielectric 21 at the center and electrodes 22 and 23 on the upper and lower surfaces is used as the capacitor component 20, and is hereinafter referred to as a chip capacitor.

  Next, the insulation in an uncured state (B stage) having a support body in which holes or notches are formed in advance in accordance with the size of the chip capacitor 20 at a part mounting position, that is, a position corresponding to the mounting position of the chip capacitor 20 Thermosetting resin (first insulating thermosetting resin) (hereinafter referred to as prepreg) 30 and B-stage insulating thermosetting resin (second insulating thermosetting resin) with no holes or the like as a lid material 40 is combined with the insulating resin plate 10 on which the chip capacitor 20 is mounted (FIG. 1D), and heat-press molding is performed to obtain a copper-clad laminate 50-1 in which the chip capacitor 20 is sealed ( FIG. 1 (e)). That is, as a result of heat and pressure molding, the periphery of the chip capacitor 20 and the positioning hole 10a are filled with the molten resin and solidified. Thereby, the chip capacitor 20 is sealed with the insulating resin plate 10 and the insulating thermosetting resins 30 and 40 so that there is no gap, and the surface of the sealing portion in the copper-clad laminate 50-1 becomes smooth. . A metal layer (second metal layer) 41 is formed on one surface of the insulating thermosetting resin 40, here the upper surface. The insulating thermosetting resins 30 and 40 are preferably the same material, but may be different materials.

  Next, as shown in FIG. 1 (f), via holes 50 a are formed by laser at positions corresponding to the electrodes 22 and 23 of the chip capacitor 20 in the copper clad laminate 50-1 incorporating the chip capacitor 20. To do. In this via hole processing, the location of the positioning hole 10a is used as a reference position.

  Subsequently, as shown in FIG. 1 (g), the metal plating 50b is applied to the via hole 50a, and the electrodes 22 and 23 of the chip capacitor 20 are connected to the metal layers 12 and 41 on the front and back sides, respectively. The circuit board 50 having the electrostatic capacity is obtained.

  As described above, when the circuit board 50 having a large capacitance is used to form a through hole and a circuit by a known method, the circuit board 50 can be used for decoupling when applied as a high frequency circuit board. A circuit board having a sufficiently large capacitance can be obtained.

  Furthermore, as shown in FIG. 1 (h), by forming a build-up layer on a circuit board 50 having a large capacitance by a known method, a capacitance sufficient for decoupling in a high-frequency circuit. Can be obtained.

  FIG. 2 shows an example of a six-layer board-based four-time build-up wiring board using the circuit board 50 having the large-capacitance capacitor 20 built in as described above, and FIG. An example of a six-layer board using the circuit board 50 is shown.

(Example 2)
Next, a second embodiment of the present invention will be described. In the second embodiment, first, an inner layer circuit board having patterns formed on both front and back surfaces is formed using a wiring board encapsulating a large-capacity chip capacitor as described above. Subsequently, a multilayer laminated board having a large capacitance by using a plurality of the inner layer circuit boards, and heat-pressing the plurality of inner layer circuit boards in combination with the insulating thermosetting resin of the B stage. Manufacturing. In addition, through holes are formed in this multilayer laminate by a known method and plating is performed to form a desired circuit, thereby providing a large capacity sufficient for high frequency circuit decoupling, for example, a capacitance of about 100 μF to 100 nF. A multilayer circuit board having the same can be obtained.

  As described above, two examples of the case of sealing a capacitor as an electronic component according to an embodiment of the present invention have been described. However, in the present invention, a component to be sealed is not limited to a chip capacitor, but other capacitor components or capacitors. Needless to say, other parts may be used. Examples of the insulating thermosetting resin include epoxy resins, BT resins, epoxy acrylate resins, phenol resins, polyimide resins, urethane acrylate resins, polyester resins, BCB (Benzocyclobutene), PBO (Polybenzoxole), and particularly epoxy resins. BT resin is preferable, but is not limited thereto.

  The wiring board according to the present invention can be applied to the general production of wiring boards that need to seal electronic components, and is particularly excellent in application to high-frequency circuits when a capacitor is sealed as an electronic component.

It is sectional drawing which showed the 1st Example of the manufacturing method of the wiring board by this invention to process order. An example of a six-layer board-based four-time build-up wiring board using a circuit board with a built-in large-capacitance capacitor obtained by the manufacturing method shown in FIG. 1 is shown. An example of a 6-layer board obtained by the manufacturing method shown in FIG. 1 and using a circuit board incorporating a large-capacitance capacitor is shown.

Explanation of symbols

10 Insulating resin plate 11 Insulating resin layer 12, 41 Metal layer 20 Chip capacitor (capacitor component)
21 Dielectric 22, 23 Electrode 30, 40 Insulating thermosetting resin 50 Circuit board 50-1 Copper-clad laminate 60 Build-up board

Claims (2)

In a method for manufacturing a wiring board incorporating an electronic component,
The electronic component is a capacitor having first and second electrodes;
In order to determine the position of the electronic component after sealing on the insulating resin plate having the first metal layer on the other surface side, the first metal layer and the insulating resin plate are placed at predetermined positions. Forming at least one positioning hole therethrough;
Placing at least one electronic component on one surface of the insulating resin plate, and observing and storing the position of the electronic component viewed from the positioning hole at that time by an imaging means ;
Covering a first insulating thermosetting resin having a hole or notch in accordance with the size of the electronic component at a position corresponding to the mounting position of the electronic component, and an upper surface side of the first insulating thermosetting resin A step of performing heat and pressure molding by combining a second insulating thermosetting resin having a second metal layer on the upper surface side that can be combined with the insulating resin plate on which the electronic component is placed. The electronic component is sealed with the insulating resin plate and the first and second insulating thermosetting resins so that there is no gap, and the positioning hole is cured in the heating and pressing molding process. surface of the sealing portion by closing the insulating thermosetting resin is made to be smooth,
Further, after the heating and pressing molding process, the first and second electrodes are formed on the first metal layer and the insulating resin plate with the positioning hole as a reference position based on the data stored in the storing process. Forming a via hole reaching one of the first and second electrodes, and forming a via hole reaching the other of the first and second electrodes in the second metal layer and the cured second insulating thermosetting resin;
Each of the formed via holes is plated to connect the first metal layer and one of the first and second electrodes, and the second metal layer and the other of the first and second electrodes. A method of manufacturing a wiring board containing an electronic component. A method for manufacturing a wiring board, wherein a build-up wiring board is obtained by further forming a build-up layer on the wiring board obtained by the manufacturing method according to claim 1 .

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