JP2003017855A - Manufacturing method of multilayer printed-wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a multilayer printed-wiring board suing an interlayer connection system due to a conductive bump with proper productivity and at a low cost. SOLUTION: A wiring board 13 has wiring layers 12 on both main surfaces, and forms a conductive bump 14 at a specific position on the wiring layers. Resin sheets 17 and 18 with copper foil have a resin layer on one main surface of the copper foil. Each conductive bump formation surface is made to oppose each resin layer of each of resin sheets 17 and 18 with copper foil for passing between a pair of heating and pressing rollers, thus heating and pressing the wiring board 13 and resin sheets 17 and 18 in one piece, and hence forming a laminated sheet, where the tip of the conductive bump 14 passes through the resin layer of each of the resin sheets with copper foil for joining to the copper foil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a multilayer printed wiring board, and more particularly to a method for manufacturing a multilayer printed wiring board having an interlayer connecting portion formed by so-called conductive bumps.

[0002]

2. Description of the Related Art In response to the multimedia era, semiconductor ICs are becoming more highly integrated, and along with this, miniaturization, thinning, weight reduction, high density, cost reduction, etc. are applied to printed wiring boards. The demands are becoming more stringent.

In order to meet such a demand, a substrate technology called a build-up type multilayer printed wiring board has been developed. Among them, a projecting conductive bump is formed on a copper foil, and the conductive bump is insulated. Attention has been paid to a method of making an electrical connection between layers by penetrating the sheet in the thickness direction.

FIG. 5 shows an example of a typical manufacturing process of a build-up type multilayer printed wiring board according to this method. As shown in the figure, in this example, first, a double-sided copper-clad laminate is used to form the first and second wiring layers 101 on both surfaces,
A wiring board 103 provided with 102 is prepared (FIG. 5).
(A)).

On the other hand, a copper foil 104 is prepared, and a conductive paste such as a silver paste is printed and cured at a predetermined position on the copper foil 104 to form a conductive bump 105 (FIG. 5B).

Next, an insulating sheet (for example, prepreg) 106 is laminated on the surface on which the conductive bumps 105 are formed, and pressure is applied to penetrate the conductive bumps 105 into the insulating sheet 106 and the exposed tips of the conductive bumps 105. Is plastically deformed so as to be crushed (FIG. 5 (c)).

Subsequently, the laminated body in which the copper foil 105 and the insulating sheet 106 are integrated as described above is formed on the wiring board 103, the tips of the conductive bumps 105, and the first wiring layer 101 provided on the wiring board 103. The layers are laminated so as to face each other, and heated and pressed (FIG. 5D). By this heating and pressing, the insulating sheet 106 is cured, and the copper foil 104 and the insulating sheet 10 are
6 is integrated with the wiring board 103, and the tips of the conductive bumps 105 are formed on the first wiring layer 10.
It is joined to 1.

Thereafter, the copper foil 104 is patterned by a conventional method to form the third wiring layer 107,
A multilayer printed wiring board in which the first wiring layer 101 and the third wiring layer 107 are interlayer-connected by the conductive bumps 105 is obtained (FIG. 5 (e)).

When manufacturing a multilayer printed wiring board having more wiring layers, a wiring board having more layers is used as the wiring board 103, or the second wiring layer 102 is used.
And the fourth and fifth wiring layers 107 on the third wiring layer 107 in the same manner as above.
Further wiring layers are provided.

The multilayer printed wiring board thus formed has a low connection resistance between the wiring layers and can make the land pattern finer, so that high-density wiring and high-density mounting are possible. Compared to other methods, it has features such as easy manufacturing process and management.

[0011]

However, in such a method, there are still points to be improved in terms of productivity and cost.

That is, in the above-mentioned method, in the heating / pressurizing step shown in FIG. 4 (d), a laminated body of the copper foil 105 and the insulating sheet 106 is laminated on the wiring board 103, and these are heated by the heating / pressurizing device. It is performed by sandwiching it between the boards via a cushion material and applying heat and pressure. The method using such a heating / pressing apparatus is time-consuming and disadvantageous in terms of productivity. Moreover, since auxiliary materials such as a cushion material are required, the manufacturing cost becomes high.

The present invention has been made in consideration of such a point, and a multilayer printed wiring board using an interlayer connection system using conductive bumps can be manufactured with high productivity and at low cost. It is an object to provide a method for manufacturing a wiring board.

[0014]

The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, a wiring board having conductive bumps previously formed for interlayer connection on a wiring layer, and The present invention has been completed by finding that the above-mentioned object can be achieved by passing such a copper foil-containing resin sheet between heating and pressure rollers and integrating them.

That is, in order to solve the above-mentioned problems, the invention described in claim 1 of the present application is a wiring having a wiring layer on one main surface and forming conductive bumps at predetermined positions on the wiring layer. A substrate and a resin sheet with a copper foil having a resin layer on one principal surface of the copper foil are integrated by passing the conductive bump forming surface and the resin layer between a pair of heating and pressing rollers. Of the multi-layer printed wiring board, which comprises heating and pressurizing to form a laminated board in which the tip of the conductive bump penetrates the resin layer of the resin sheet with the copper foil and is bonded to the copper foil. It is a manufacturing method.

In order to solve the above problems, a wiring substrate having wiring layers on both main surfaces and conductive bumps formed at predetermined positions on each of these wiring layers, and a resin layer on one main surface of a copper foil. Two resin sheets with a copper foil, each of which is provided with the above, are passed integrally between a pair of heating and pressing rollers with the conductive bump formation surface and the resin layer of each of the resin sheets with a copper foil facing each other. A multilayer printed wiring board comprising a step of heating and pressurizing to form a laminated board bonded to the copper foil by penetrating a resin layer of the resin sheet with the copper foil facing the tips of the conductive bumps. Is a manufacturing method.

In the method for manufacturing a multilayer printed wiring board according to the first and second aspects of the present invention, the wiring board and the resin sheet with copper foil are heated and pressed while passing between a pair of heating and pressing rollers. While being integrated, the tips of the conductive bumps penetrate the resin layer of the resin sheet with copper foil and are bonded to the copper foil. Therefore, the time required for the heating and pressurizing step can be shortened and the productivity can be improved as compared with the conventional method using the heating and pressurizing apparatus. Further, unlike the conventional method, auxiliary materials such as a cushion material are not required, so that the manufacturing cost can be reduced.

In the present invention, the wiring board may have at least one inner wiring layer as described in claim 3.

The conductive bumps can be formed by a method of screen-printing and hardening a conductive paste as described in claim 4. According to such a method, the bonding area with the copper foil can be made smaller than in the conventional case, and the land area can be reduced to achieve a finer wiring pattern.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram schematically showing an embodiment of a method for manufacturing a multilayer printed wiring board according to the present invention.

In this embodiment, first, each wiring layer 11 of the wiring substrate 13 having the wiring layers 11 and 12 on both main surfaces,
A conductive paste is screen-printed on 12 to form conical conductive bumps 14 (FIG. 1A).

The wiring board 13 is a double-sided copper-clad laminate such as a glass epoxy copper-clad laminate or a glass-polyimide copper-clad laminate which is conventionally used as a material for a multilayer printed wiring board and has copper foils bonded to both sides. A board with the required wiring pattern formed on both sides of the board, or one layer or both sides of which copper foil is further laminated and integrated through an insulating sheet to form a multilayer, and the required wiring pattern is formed on those copper foils. Used are used.

The conductive paste used for forming the conductive bumps 14 is at least one conductive material selected from silver, gold, copper, nickel, platinum, tungsten, molybdenum, palladium, rhodium, solder powder and the like. And a resin frit such as a polycarbonate resin, a polysulfone resin, a polyester resin, a phenoxy resin, a phenol resin, or a polyimide resin, or a glass frit binder component.

The conductive bumps 14 can be formed by copper, in addition to the above-described method of screen-printing the conductive paste.
It may be formed by a so-called electroforming method of plating a metal such as gold, silver, tin or solder, a so-called etching method of forming a layer made of a similar metal and etching, a method of joining fine wires made of a similar metal, or the like. Good.

However, in the method of screen-printing the conductive paste, since the conductive bumps 14 are formed in a shape in which at least the bottom surface is larger than the tip (usually a conical shape), the land area can be reduced. Since it is possible to further miniaturize the wiring pattern, it is more advantageous in terms of high density.

Next, the wiring board 13 on which the conductive bumps 14 are formed in this manner is used as a resin sheet 1 with a copper foil in which resin layers 17b and 18b are provided on one main surface of the copper foils 17a and 18a.
7, 18 and the conductive bump forming surfaces 15 and 16 and the resin layers 17b and 18b are opposed to each other and passed between a pair of heating and pressing rollers to integrally heat and press the tips of the conductive bumps 14. A laminated board 19 is obtained which penetrates through the resin layers 17b and 18b of the resin sheets 17 and 18 with copper foils and is bonded to the copper foils 17a and 18a (FIG. 1 (b)).

In carrying out this process, for example, as shown in FIG.
A device as shown in can be used. That is,
FIG. 2 is a diagram schematically showing an example of an apparatus used in this step. In FIG. 2, 201 and 202 denote a pair of heating and pressing rollers, and on both sides thereof, conveyors 203 and 204 for conveying the wiring board 13 on which the conductive bumps 14 are formed are conveyed in the arrow direction of the drawing. It is set up. Further, resin sheet supply rollers 205 and 206 with copper foil for supplying the resin sheets 17 and 18 with copper foil are arranged above and below the conveyor 203 on the upstream side of the conveyors 203 and 204. There is.

In such an apparatus, the wiring board 13 on which the conductive bumps 14 are formed is transferred to the transfer conveyor 203.
The resin sheet supply roller 20 with the copper foil
Resin sheet 17 with copper foil drawn out from 5, 206,
Along with 18, the conductive bump forming surfaces 15 and 16 and the resin layers 17b and 18b of the resin sheets 17 and 18 with copper foils are passed between a pair of heating and pressing rollers 201 and 202 so as to be integrated. When heated and pressed, the tips of the conductive bumps 14 have respective resin layers 17 of the resin sheets 17 and 18 with copper foils.
The laminated plate 19 is formed by penetrating b and 18b and joined to the copper foils 17a and 18a, and is conveyed by the conveyer conveyor 204.

As the resin sheets with copper foil 17 and 18 used here, for example, epoxy resin, polyimide resin, and their modified resins, which are held in a semi-cured state, are formed on one main surface of the copper foil. A resin having a thickness of about 30 μm to 200 μm, which is made of a curable resin or a thermoplastic resin such as a polycarbonate resin, a polysulfone resin, a thermoplastic polyimide resin, a tetrafluoropolyethylene resin, a hexafluoropolypropylene resin, or a polyetheretherketone resin. The thing which provided the layer is mentioned. The resin layer may contain an insulating inorganic or organic filler.

The laminated plate 19 thus obtained is housed in a heating chamber, if necessary, to sufficiently cure the resin layers 17a and 18a of the resin sheets 17 and 18 with copper foil. The respective copper foils 17a, 18a are patterned by a conventional method to form the required wiring layers 20, 21 to obtain a multilayer printed wiring board (FIG. 1 (c)).

In such a manufacturing method, the wiring board 1 in which the conductive bumps 14 are formed on the respective wiring layers 11 and 12
3 and the copper foil-attached resin sheets 17 and 18 are passed between a pair of heating and pressing rollers 201 and 202 to be heated and pressed to be integrated, so that heating and pressurizing devices are used in comparison with the conventional method. The time required for the pressure integration step can be shortened and the productivity can be improved. Further, unlike the conventional method, auxiliary materials such as a cushion material are not required, so that the manufacturing cost can be reduced.

In particular, when the step shown in FIG. 1B is performed using the apparatus shown in FIG. 2, the wiring board 13 and the resin sheets 17 and 18 with copper foil should be laminated and integrated at the same time. In addition, the resin sheets 17 and 18 with copper foil can be continuously laminated and integrated on the plurality of wiring boards 13, so that the manufacturing efficiency can be further improved.

In the example described above, the wiring board 13
The two wiring layers 20 and 21 are collectively multilayered on both main surfaces of the above. In the present invention, first, the conductive bump 14 is formed on one wiring layer 11 of the wiring substrate 13, and After the copper foil-coated resin sheet 17 is laminated and integrated on both conductive bump forming surfaces 15, conductive bumps 14 are similarly formed on the other wiring layer 12, and both conductive bump forming surfaces 16 are formed.
Alternatively, the resin sheet with copper foil 18 may be laminated and integrated.

Further, in the present invention, as shown in FIG. 3, a new wiring layer 20 may be provided only on one wiring layer 11 of the wiring board 13.

If necessary, the steps similar to those described above may be repeated on the wiring layers 20 and 21 thus formed to obtain a multilayer printed wiring board having more wiring layers. You can FIG. 4 shows an example of a multilayer printed wiring board manufactured by such a method, in which a new wiring layer 22, on the wiring layers 20 and 21 of the multilayer printed wiring board obtained in the above embodiment, 23
Are provided, and between the wiring layer 20 and the wiring layer 22 and between the wiring layer 21 and the wiring layer 23, respectively, the wiring layer 2
It has a structure in which it is electrically joined by the conductive bumps 14 provided on the parts 0 and 21. Note that, in FIG. 4, reference numerals 24 and 25 denote resin sheets with copper foil, which are laminated to form the wiring layers 22 and 23 and are configured in the same manner as the resin sheets with copper foil 17 and 18.

[0037]

EXAMPLES Next, examples of the present invention will be described.

Example Epoxy vinyl ester resin (trade name of Showa High Polymer Co., Ltd.
VR-60M-3X; 100 parts by weight of epoxy resin in which 33% of epoxy groups are esterified with methacrylic acid), 1 part by weight of benzoyl peroxide (decomposition temperature 105 ° C), and 3 parts by weight of diaminodiphenylmethane as a curing agent, methyl ethyl ketone And ethyl cellosolve mixed solvent (mixed weight ratio 40: 6
0) Dissolved in 80 parts by weight. This composition is applied to the roughened surface side of a copper foil having a thickness of 18 μm by a roll coater, dried by heating at a temperature of 130 ° C. and semi-cured, and a resin sheet with a copper foil having a thickness of 60 μm is produced and rolled. I wound up.

On the other hand, each copper foil of a copper-epoxy double-sided copper-clad laminate (trade name TLC-555M manufactured by Toshiba Chemical Co., Ltd.) having a copper foil thickness of 18 μm and a plate thickness of 0.4 mm, which has been through-hole formed in advance, is patterned on both sides. After creating a wiring board having a wiring layer in, at the required position on each wiring layer of this double-sided wiring board,
Conductive paste (Toshiba Chemical Co., Ltd., trade name MS-89) is screen-printed to a bottom diameter of about 100 μm and a height of about 120 μ.
m conical conductive bumps were formed.

Next, by using the apparatus shown in FIG. 2, the resin sheet with the copper foil pulled out from the wiring board and the two rollers is attached to the conductive bump forming surface of the wiring board with the resin surface of the resin sheet with the copper foil. After being passed between the heating and pressing rollers which are opposed to each other and heated to 130 ° C. to be integrated, they were cut into a predetermined size and further heated at 160 ° C. for 1 hour. After cooling, the copper foils on both sides were patterned to obtain a 4-layer printed wiring board having a thickness of 0.48 mm.

When a continuity test was conducted on the obtained four-layer printed wiring board, no problems were found in all the connections.

It is needless to say that the present invention is not limited to the above-mentioned embodiments and can be modified and carried out within the scope not departing from the spirit of the invention.

[0043]

As described above, according to the method for manufacturing a multilayer printed wiring board of the present invention, a wiring board having conductive bumps previously formed on the wiring layer for interlayer connection and a resin sheet with a copper foil are provided. Since it is heated and pressed by passing it between a pair of heating and pressing rollers to be integrated, it is possible to reduce the time required for the heating and pressing molding process, as compared with the method using a conventional heating and pressing machine. Productivity can be increased. Further, unlike the conventional method, auxiliary materials such as a cushion material are not required, so that the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram schematically illustrating an embodiment of a method for manufacturing a multilayer printed wiring board according to the present invention.

FIG. 2 is a diagram schematically showing an example of an apparatus used in the present invention.

FIG. 3 is a schematic sectional view showing an example of a multilayer printed wiring board according to another embodiment of the present invention.

FIG. 4 is a schematic sectional view showing an example of a multilayer printed wiring board according to still another embodiment of the present invention.

FIG. 5 is a diagram schematically illustrating a conventional method for manufacturing a multilayer printed wiring board.

[Explanation of symbols]

11, 12, 20, 21, 22, 23 ... Wiring layer 13 ………… Wiring board 14 ... Conductive bump 15, 16 ......... Conductive bump formation surface 17, 18, 24, 25 ... Resin sheet with copper foil 17a, 18a ......... Copper foil 17b, 18b ......... Resin layer 201, 202 ......... Heat pressure roller 203, 204 ... Transport conveyor

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Claims (4)

[Claims] 1. A wiring board having a wiring layer on one main surface and conductive bumps formed at predetermined positions on the wiring layer, and a copper foil having a resin layer on one main surface of the copper foil. Resin sheet,
The conductive bump forming surface and the resin layer are opposed to each other and are heated and pressed together by passing between a pair of heating and pressing rollers, and the tips of the conductive bumps form the resin layer of the resin sheet with the copper foil. A method of manufacturing a multilayer printed wiring board, comprising the step of forming a laminated board that penetrates and is bonded to the copper foil. 2. A wiring board having wiring layers on both main surfaces and conductive bumps formed at predetermined positions on each of these wiring layers; and copper having a resin layer on one main surface of a copper foil. The two resin sheets with foil are integrally heat-pressed by passing the conductive bump forming surface and the resin layer of each resin sheet with copper foil, respectively, and passing them between a pair of heating and pressing rollers. A method for manufacturing a multilayer printed wiring board, comprising the step of forming a laminated board bonded to the copper foil by penetrating a resin layer of the resin sheet with a copper foil, the tips of the conductive bumps facing each other. 3. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the wiring board has at least one inner wiring layer. 4. The method for manufacturing a multilayer printed wiring board according to claim 1, wherein the conductive bumps are formed by screen-printing and curing a conductive paste.