JPH05160574A - Multilayer printed circuit board and method of manufacturing it - Google Patents

Abstract

PURPOSE:To provide a multilayer printed circuit board of a structure, in which a recessed part for electronic component mounting use can be formed by a spot facing work after a plurality of printed circuit boards are joined in a multilayer structure, and a structure, which is not required an accurate processing accuracy, and a method of manufacturing such a printed circuit board. CONSTITUTION:An opening part 6 is provided in a bonding agent layer 5 interposed between laminated printed circuit boards 2 and 4 and a recessed part 14 for electronic component mounting use is constituted of the opening part 6 and an opening part (is formed by a spot facing work) in the board 2. Insulative members 7 are provided along the inner side of the opening part 6 in the layer 5 and when the laminated boards 2 and 4 are hot-pressed, the outflow of a bonding agent to the side of the opening part 6 is dammed up. One part of each insulative member 7 is removed by a spot facing work.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed wiring board capable of embedding an electronic component such as an IC in the board and a method for manufacturing the same.

[0002] The multilayer printed wiring board is made into a card, which is used as a cash card for a cash card, an identification,
It is used to form an ID card used for confirmation, a TC card used as a telephone card, an MC card used for medical charts, and the like, and its use is expanding in recent years.

[0003]

2. Description of the Related Art Conventionally, electronic parts such as ICs are mounted on the surface of a printed wiring board. However, for products whose total thickness is limited, the printed wiring board itself should be thinned or the electronic parts such as ICs should be thinned. We have responded by thinning the parts themselves.

However, in order to thin the printed wiring board itself (multilayer), it is necessary to thin the members for laminating the boards, which makes it difficult to handle the members in manufacturing, and the insulating characteristics between the boards are reduced. It was also difficult to secure.

Further, there is a limit to thinning electronic parts such as ICs without sacrificing their characteristics, and it is inevitable to form a certain thickness.

In view of such circumstances, in recent years, printed wiring boards are laminated in multiple layers, and a recessed portion for mounting an electronic component is formed in a required portion by spot-working, and an IC is mounted in the recessed portion for mounting an electronic component. It has been proposed to embed other electronic components to reduce the overall thickness.

[0007]

As described above, a plurality of printed wiring boards are laminated and integrated, and then a counter boring process is applied to a necessary portion to form a recess for mounting an electronic component. The multi-layer printed wiring board, without damaging the printed wiring provided in the printed wiring board,
It is difficult to say that it is a suitable multilayer printed wiring board because it is difficult to perform spot facing processing accurately.

A printed wiring board to be laminated is preliminarily formed with an opening for forming a concave portion for mounting an electronic component so that a spot facing process after integration is unnecessary (for example, Japanese Patent Publication No.
No. 41998, No. 3-41999) was also known, but in the processing steps such as through-hole plating for the multilayer substrate, outer layer pattern formation, resist, marking, etc., the recess for mounting electronic parts was closed with a cover material, etc. Since it is necessary to remove the cover material later, the manufacturing becomes complicated.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and after a plurality of printed wiring boards are multilayered, a recess for mounting electronic parts can be formed by counter boring. It is an object of the present invention to provide a multilayer printed wiring board having a structure that does not require precise processing accuracy and a method for manufacturing the same.

A multilayer printed wiring board of the present invention which achieves the above object is a multilayer printed wiring board having a recess for mounting electronic parts, wherein an opening is formed in an adhesive layer interposed between the laminated printed wiring boards. The electronic component mounting recess is formed by the opening and the opening of the printed wiring board, and the insulating member is provided along the inside of the opening of the adhesive layer. .. The insulating member is an insulating member that is separate from the adhesive layer, or the adhesive layer is cured.

Further, the manufacturing method of the present invention for manufacturing the above-mentioned multilayer printed wiring board is such that a plurality of printed wiring boards are laminated and integrated, and then a recess for mounting electronic parts is formed in the board. In a method for manufacturing a wiring board, a plurality of printed wiring boards, in which an adhesive layer having an opening is provided between the stacked printed wiring boards, an insulating member is attached to the openings, and the layers are stacked by a thermal pressure press. Is integrated, and then a part of the printed wiring board and the insulating member is cut to expose the opening to one side of the laminated board.

The insulating member is an annular member along the periphery of the opening of the adhesive layer or a plate-like member that covers the opening.

Another method for manufacturing a multilayer printed wiring board according to the present invention is a multilayer printed wiring board in which a plurality of printed wiring boards are laminated and integrated, and then an electronic component mounting recess is formed in the board. In the manufacturing method of 1., a plurality of printed wirings are provided by interposing an adhesive layer in which an opening and a thermosetting portion along the edge of the opening are formed in advance between the stacked printed wiring boards, and are stacked by a thermal pressure press. After the substrates are integrated, the printed wiring board and a part of the thermosetting portion are cut to expose the opening on one side of the laminated substrate.

In still another method of manufacturing a multilayer printed wiring board according to the present invention, a plurality of printed wiring boards are laminated and integrated, and then a recess for mounting electronic parts is formed in the board. In the manufacturing method, a thermosetting portion and an adhesive layer having a groove formed along the inside of the peripheral edge of the thermosetting portion are interposed in advance between the laminated printed wiring boards,
It is characterized in that a plurality of printed wiring boards laminated by a hot press are integrated, and then the printed wiring board and a part of the thermosetting portion are cut to form a recess for mounting an electronic component.

[0015]

According to the present invention, there is provided a printed wiring which has an electronic component mounting recess in which an IC and other electronic components can be embedded and which can be connected to the electronic component, is free from scratches, and has an adhesive layer. There is provided a multilayer printed wiring board having a printed wiring not covered with the adhesive in the inside of the recess.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIGS. 1A to 1C are views showing the manufacturing process of the first embodiment in which the printed wiring pattern has four layers. First, the printed wiring pattern 1 having the second layer is provided. The wiring board 2 and the printed wiring board 4 provided with the third-layer printed wiring pattern 3 were laminated with the adhesive layers 5 and 5 interposed therebetween (a). As the printed wiring boards 2 and 4, it is possible to use not only a glass epoxy substrate but also a glass triazine resin substrate or the like, which is usually called a copper clad laminate. In the example, a glass epoxy substrate having a thickness of 0.1 mm was used. Printed wiring pattern 1,
3 had a thickness of 35 μm of copper foil. In the figure, 10 and 11 are
It is a copper foil on the outer surface.

For the adhesive layer 5, a heat resistant adhesive sheet such as glass cloth impregnated with an uncured epoxy resin can be used. In the example, two epoxy resin-impregnated glass cloths (prepregs) having a thickness of 0.06 mm were used in a stacked manner. In the two adhesive layers 5 and 5, rectangular openings 6 and 6 are formed in advance, the openings 6 and 6 are aligned and laminated, and a rectangular annular insulation is formed in the openings 6 and 6. The elastic member 7 was attached along the inner walls of the openings 6, 6. The insulating member 7 is made of a resin such as epoxy, phenol, polyester, polyimide, Teflon, and polysulfone, and a base material such as paper and glass without a copper foil, an acrylic plate, a silicone rubber plate, and Teflon. It is possible to use a material having electric characteristics as an insulating layer such as a plate. In the example, a frame-shaped insulating member 7 was punched out from a 0.12 mm-thick sheet made of a glass substrate and an epoxy resin and used.

As described above, the printed wiring boards 2 and 4 laminated with the adhesive layers 5 and 5 interposed therebetween were subjected to hot pressure press molding by an ordinary method to integrate the printed wiring boards 2 and 4. In the hot pressure press molding, the adhesive (epoxy resin) of the adhesive layers 5 and 5 flows and is subsequently cured by heat.
The outflow to the openings 6, 6 is blocked by an insulating member 7, and the upper and lower surfaces of the insulating member 7 adhere to the printed wiring boards 2 and 4, and the outer surfaces of the adhesive layers 5 and 5. It adheres to the inner walls of the openings 6, 6.

Next, through holes 8 are formed in the laminated and integrated printed wiring boards 2 and 4, and through hole plating 9 is formed, and then the outer surfaces of the printed wiring boards 2 and 4 are etched. Then, the printed wiring pattern 12 of the first layer and the printed wiring pattern 13 of the fourth layer were formed (b). After that, resist printing and marking printing were performed (not shown).

Then, from the printed wiring board 2 side,
The positions corresponding to the openings 6 and 6 of the adhesive layers 5 and 5 were cut by counter boring to expose the openings 6 and 6 to form the electronic component mounting recess 14 (c). The depth of the spot facing is 12 from the outer surface of the printed wiring board 2.
It was set to 0 to 170 μm. A part of the upper side of the insulating member 7 attached to the openings 6, 6 was removed by cutting. In the printed wiring pattern 3 of the third layer of the printed wiring board 4,
At the positions of the openings 6, 6, there are formed conductor inner layer patterns 3a, 3a for connecting the lead wires of the electronic component and a fixing seat 3b for the electronic component, and electroless gold plating is applied to these. Bonding is possible.

FIG. 2 shows the multilayer printed wiring board 15 obtained in the above embodiment. The adhesive of the adhesive layers 5 and 5 is prevented from flowing out by the insulating member 7 as described above, so that the conductor inner layer patterns 3a and 3a were not covered with the adhesive. In addition, the electronic component mounting recess 1
Since the spot boring process for forming 4 was performed to a depth of about half of the insulating member 7, it was possible to perform it without damaging the conductor inner layer patterns 3a, 3a and the fixed seat 3b.

FIG. 3 shows an embodiment in which the rectangular annular insulating member 7 of the above embodiment is replaced with an insulating member made of a material having a size to cover the opening of the adhesive layer.

In this embodiment, the printed wiring pattern has six layers, and the printed wiring boards 17 and 1 on which the printed wiring patterns 16 and 16 are formed are the same as in the previous embodiment.
Adhesive layer 1 in which three sheets 7 and openings 18 and 18 are formed
9, 19 and an adhesive layer 20 having no opening,
20 was laminated (a). In the figure, 25 and 26 are copper foils on the outer surface. Adhesive layers 19 and 1 having openings 18 and 18 formed therein
Reference numeral 9 indicates the openings 1 and 18 which are laminated to form the opening 1
8 and 18 are insulating members 21 each having a size that covers the opening.
I put on. On one side surface (lower surface) of the insulating member 21, a groove 22 having a V-shaped cross section is annularly provided along the edge portion.
The groove 22 has a depth of 0.1 mm, while the insulating member 21 has a thickness of 0.15 mm.

The three printed wiring boards 17, 17 thus laminated are subjected to hot pressure press molding in the same manner as in the above embodiment, followed by processing of the through holes 23 and through hole plating 24, and at the same time the outer surface As a result, the printed wiring patterns 27 of the first layer and the sixth layer were formed, and resist printing and marking printing were performed. After that, the position corresponding to the openings 18, 18 is counterbored (depth 4).
40 μm) An electronic component mounting recess 28 was formed (b).

In the case of this embodiment, the adhesive of the adhesive layers 19 and 19 which flow at the time of hot press molding is dammed at the groove 22 of the insulating member 21, and the surface 29 surrounded by the groove 22 is blocked. It is possible to prevent outflow to a part. Therefore, when the depth reaching the groove 22 of the insulating member 21 is reached by the spot facing process, the central portion including the surface 29 can be removed, and the conductor inner layer pattern 16a is formed on the bottom of the electronic component mounting recess 28. , 16a and the fixed seat 16b are exposed. These patterns are not covered with adhesive and are not damaged by the spot facing.

The conductor inner layer pattern 16a and the fixed seat 16b were subjected to electroless gold plating in the same manner as in the above-mentioned embodiment so as to be compatible with bonding. The electroless gold plating may be either partial gold plating after resist printing or whole surface gold plating before resist printing, but partial gold plating is advantageous in view of the cost of gold plating.

Next, FIGS. 4 and 5 show an embodiment in which the insulating members 7 and 21 are not used.

FIG. 4 shows a multilayer printed wiring board having four printed wiring patterns similar to those shown in FIG. 1, and the openings 6 of the adhesive layers 5, 5 interposed between the printed wiring boards 2, 4.
At the edge of 6, heat-cured portions 30, 30 which have been heat-cured in advance are provided over a predetermined width.

The other parts are the same as in the first embodiment. Adhesive outflow during hot pressure press molding is caused by the thermosetting part 3
It can be stopped at 0 or 30. Therefore, the recesses 31 for mounting electronic components can be formed by exposing the openings 6, 6 by counter boring after hot-pressing.
The insulating member 30a formed by the thermosetting portion 30 can be formed in an annular shape along the inside of the bottom of the electronic component mounting recess 31.

FIG. 5 is also a multilayer printed wiring board similar to that of the first embodiment. In the adhesive layers 5 and 5, a rectangular thermosetting portion 32 is formed in advance without forming an opening, and On one side surface (lower surface) of the thermosetting portion 32, a groove 33 having a V-shaped cross section was formed in a rectangular shape along the periphery of the thermosetting portion.

In the case of this embodiment, the flow-out of the adhesive during hot pressure press molding can be stopped by the groove 33. However, the recess 34 for mounting the electronic component can be formed by the counterbore processing after the hot pressure press molding, and the insulating member 32a by the thermosetting portion 32 can be formed along the inside of the bottom portion.

[0033]

As described above, according to the present invention, it is possible to obtain the multilayer printed wiring board having the recessed portion for mounting the electronic component in the board by the usual manufacturing technique and processing technique for the multilayer substrate.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a manufacturing process of a first embodiment of the present invention, in which (a) is a view showing a state in which printed wiring boards are laminated and hot-pressed, (b) is a through hole, FIG. 3C is a view showing a state in which an outer surface pattern is formed, and FIG. 6C is a view showing a state in which a recess for mounting an electronic component is processed.

FIG. 2 is also a partial perspective view of the first embodiment.

FIG. 3 is a partial cross-sectional view of a second embodiment of the present invention, (a)
FIG. 4B is a view showing a state in which printed wiring boards are laminated and subjected to hot pressure press molding, and FIG.

FIG. 4 is a partial cross-sectional view of a third embodiment of the present invention, (a)
FIG. 4B is a view showing a state in which printed wiring boards are laminated and subjected to hot pressure press molding, and FIG.

5A and 5B are partial cross-sectional views of a fourth embodiment of the present invention, FIG. 5A is a view showing a state in which printed wiring boards are laminated and hot-pressed, and FIG. 5B is a state in which a recess for mounting electronic parts is processed. FIG.

[Explanation of symbols]

1, 3, 12, 13, 16, 27 Printed wiring patterns 2, 4, 17 Printed wiring boards 5, 19, 20 Adhesive layers 6, 18 Openings 7, 21, 30a, 32a Insulating members 14, 28, 31 , 34 Recesses for mounting electronic components 15 Multilayer printed wiring board 22, 33 Grooves 30, 32 Thermosetting part

Claims (7)

[Claims] 1. A multilayer printed wiring board having a recess for mounting electronic parts, wherein an opening is provided in an adhesive layer interposed between the laminated printed wiring boards, and the opening and the printed wiring board are provided. A multilayer printed wiring board, characterized in that the opening constitutes the recess for mounting electronic parts, and an insulating member is provided along the inside of the opening of the adhesive layer. 2. The multilayer printed wiring board according to claim 1, wherein the insulating member is an insulating member separate from the adhesive layer. 3. The multilayer printed wiring board according to claim 1, wherein the insulating member is obtained by curing an adhesive layer. 4. A method for manufacturing a multilayer printed wiring board, wherein a plurality of printed wiring boards are stacked and integrated, and then an electronic component mounting recess is formed in the board. A plurality of printed wiring boards, which are laminated with each other by a thermal pressure press, are integrated with each other by interposing an adhesive layer having a portion formed therebetween, and the insulating member is attached to the opening. A method of manufacturing a multilayer printed wiring board, characterized in that a portion is cut to expose the opening on one side of the laminated substrate. 5. The method for manufacturing a multilayer printed wiring board according to claim 4, wherein the insulating member is an annular member along the periphery of the opening of the adhesive layer or a plate-like member covering the opening. 6. In a method for manufacturing a multilayer printed wiring board, wherein a plurality of printed wiring boards are laminated and integrated, and then an electronic component mounting recess is formed in the board. After the opening and an adhesive layer formed with a thermosetting portion along the edge of the opening are interposed, and a plurality of printed wiring boards laminated by a thermal pressure press are integrated, the printed wiring board and the heat A method for manufacturing a multilayer printed wiring board, characterized in that a part of the cured portion is cut to expose the opening on one side of the laminated substrate. 7. A method for manufacturing a multilayer printed wiring board in which a plurality of printed wiring boards are stacked and integrated, and then a recess for mounting electronic parts is formed in the board. Interposing a thermosetting portion and an adhesive layer having a groove formed along the inside of the peripheral edge of the thermosetting portion,
A multilayer printed wiring board characterized by forming a recess for mounting electronic parts by cutting a part of the printed wiring board and the thermosetting portion after unifying a plurality of laminated printed wiring boards by a hot press. Manufacturing method.