JP3238901B2 - Multilayer printed wiring board and method of manufacturing the same - Google Patents

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 having a plurality of wiring patterns on both sides and an inner layer, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, as electronic devices have become smaller, thinner, lighter, and more sophisticated, various electronic components constituting the electronic devices have been reduced in size and thickness, and these electronic components have been mounted. Various technologies have been actively developed for printed wiring boards to enable high-density mounting.

In recent years, in particular, with the rapid development of mounting technology, it has been strongly required to supply a multilayer printed wiring board at a low cost, which can mount semiconductor chips such as LSIs at a high density and can cope with high-speed circuits. It has been requested. By the way, such a multilayer printed wiring board has
It is required to have high electrical connection reliability and excellent high-frequency characteristics between a plurality of wiring patterns formed at a fine wiring pitch.

A multilayer printed wiring board in which electrical connection between layers is made by a conventional through-hole structure by drilling and etching or plating of a copper-clad laminate is extremely satisfactorily capable of meeting such a demand. It has become difficult. So, in order to solve such a problem,
Manufacturing methods for printed wiring boards with new structures and high-density wiring are being developed.

One of the recent techniques for forming a fine pattern corresponding to high-density surface mounting is a single-plate pressing method. This single-plate press method is based on high-speed plating technology and transfer method. First, a wiring pattern is formed on a metal plate by high-speed electrolytic copper plating, and a semi-cured resin plate such as prepreg is formed. From both sides, sandwich the metal plate on which the wiring pattern is formed so that the wiring pattern is in contact with the surface of the resin plate, and superimpose it. Transfer to plate. Thereafter, the metal plate is peeled off, the resin plate is drilled to form a through hole, and the inner wall of the through hole is plated with copper to connect the wiring patterns on both surfaces to a circuit. Both the line width and the line interval obtained by this method are 40 μm at the manufacturing level.

On the other hand, instead of the copper plating conductor on the inner wall of the through hole, which has been the mainstream of the conventional interlayer connection of the multilayer printed wiring board, the inner via hole is filled with a conductor to improve connection reliability. A resin multilayer substrate having an all-layer IVH structure capable of realizing miniaturization of a substrate size and high-density mounting by forming an inner via hole directly under a component land or between arbitrary layers (Japanese Patent Laid-Open No. 6-26834).
No. 5).

Hereinafter, an example of a method for manufacturing the resin multilayer substrate having the all-layer IVH structure will be described. 9 and 10 are process cross-sectional views showing the manufacturing method. As shown in FIG. 9 (a), first, a support 1 made of a prepreg such as an aramid epoxy resin coated on both sides with a release film 7 is used. A via hole 2 is formed by drilling a necessary portion using a laser processing machine, and the via hole 2 is filled with a conductive paste 3 as shown in FIG.
Is peeled off to obtain the intermediate connector 20. Next, FIG.
As shown in FIG. 2, the copper foil 4 is arranged on both surfaces of the intermediate connector 20 and is heated and pressed to harden the support 1 and the conductive paste 3 which have been in the prepreg state. At the same time, the copper foil 4 on both sides is adhered to the support 1 and the conductive paste 3
To make electrical connection. Next, as shown in FIG. 1D, the copper foil 4 on both sides is etched by a conventional photolithography method to form wiring patterns 5a and 5b, thereby obtaining a double-sided wiring board 6.

Further, in the same steps as FIGS. 9A and 9B, the positions of the via holes 2 of the double-sided wiring board 6 are different from those of the two substrates similar to the support 1 described above. Via holes 2a and 2b are formed at positions, and the via holes 2a and 2b are filled with conductive pastes 3a and 3b to form an intermediate connector 20a and an intermediate connector 20b.
Then, as shown in FIG. 10E, the intermediate connector 20a and the intermediate connector 20b are arranged at predetermined positions on both surfaces of the double-sided wiring board 6, and the copper foil 4a and the copper foil 4b are arranged outside the intermediate connectors 20a and 20b. Then, heating and pressurization are performed again to form a multilayer. Next, in the same manner as in the step of FIG.
As shown in FIG. 10 (f), the outermost copper foils 4a, 4b are etched by photolithography to obtain a four-layer wiring board 9 having outer layer wiring patterns 8a, 8b.

[0009]

However, in the above-mentioned resin multilayer substrate having an all-layer IVH structure, an aramid epoxy prepreg obtained by impregnating an aramid nonwoven fabric with an epoxy resin is used for the adhesive insulator of all layers. There were the following problems caused by the above.

(1) An insulating substrate made of an organic non-woven fabric such as aramid fiber deteriorates adhesion between a substrate material and a metal foil such as a copper foil. Therefore, the insulating substrate is formed on the outer surface of the outermost layer of the resin multilayer substrate. When an electronic component or the like is mounted on a wiring pattern, it is difficult to obtain high mounting strength.

(2) Since the wiring pattern forming method of the inner and outer layer copper foils is the conventional photolithographic method, the formation density such as the wiring pitch and the wiring width is equal to that of the conventional one, and the multi-layer printing is performed. On the surface of the outermost layer substrate of the wiring substrate, the shape of the aramid nonwoven fabric fiber when the aramid epoxy prepreg is thermocompression-bonded is formed as it is, and irregularities are formed. When a wiring pattern is formed on a substrate having such irregularities by a photolithographic method, a gap is easily formed between the copper foil and the etching resist, and the etching solution penetrates into this gap, making it difficult to form a pattern as designed. However, there has been a limit in miniaturization of wiring patterns. In particular, there is a problem that it is not possible to form a wiring pattern as designed on the outer surface of the outermost layer of a multilayer printed wiring board, which is required to mount ultra-small electronic components such as an LSI bare chip at a high density.

(3) Since the aramid epoxy prepreg is in a state in which the fibrous base material is impregnated with a resin material, the internal structure of the prepreg is likely to be non-uniform, and the close contact between the release film and the aramid epoxy prepreg. When the conductive paste is filled into the through holes, the conductive paste is likely to enter the boundary between the release film and the prepreg. Therefore, when the distance between the through-hole and the wiring pattern formed on the substrate is small, an electrical short-circuit is likely to occur, so that the density of the wiring pattern has been limited.

[0013] Therefore, research and development for solving these problems have been continuously conducted. In order to solve the above-mentioned problem (1), the surface of an insulating base material made of an organic non-woven fabric impregnated with an epoxy resin is insulated. There is disclosed a technique (JP-A-8-316598) for improving the adhesive strength between a substrate material and a metal foil by covering with an adhesive resin.
Regarding the problems (2) and (3), a sufficient solution has not yet been obtained. However, as a solution from the wiring pattern formation surface to the problem (3), a technique for manufacturing a printed wiring board by transferring a wiring pattern has been proposed. In this method, a wiring pattern resist is coated on the surface of a conductive release support plate, a wiring pattern is formed by plating using the wiring pattern resist, and the wiring pattern is formed on a multilayer printed wiring board. It is to be transferred by thermocompression bonding to the surface of the outer layer substrate to form a wiring pattern having a fine line width and wiring pitch (Naoki Fukutomi et al., "Development of fine wiring technology by wiring transfer method", Electronic Information Transactions of the Telecommunications Society of Japan Vol.J72-C No.
4, PP243-253, 1989).

However, even in such a wiring pattern transfer method, when the printed wiring board to be transferred is an aramid epoxy prepreg substrate, the surface of the printed circuit board has irregularities when the wiring pattern is transferred. It has been extremely difficult to accurately transfer an ultrafine wiring pattern onto a substrate with high accuracy.

The present invention has been made to solve the above-mentioned problems, and makes use of the advantages of the above-mentioned resin multilayer substrate having an all-layer IVH structure and solves the problems.
It is an object of the present invention to provide a multilayer printed wiring board having high density and high reliability of component mounting and a method of manufacturing the same.

[0016]

In order to achieve the above object, a first aspect of the present invention (corresponding to claim 1) is to provide a plurality of insulators having a through hole and a conductor embedded in the through hole. An insulating substrate laminate composed of a substrate, and a wiring pattern disposed between each of the plurality of insulating substrates and on at least one outer surface of the insulating substrate laminate and connected by the conductor; wherein the insulating substrate of the structure material of the outermost layer of the wiring pattern is arranged Ri heat resistant organic sheet der, wherein the insulating substrate other than the outermost layer
A multilayer printed wiring board characterized in that the whole or a part is a resin-impregnated fiber sheet .

In the multilayer printed wiring board according to the first aspect of the present invention, since the surface of the outermost insulating substrate is smoothed and the wiring pattern is formed, the wiring pattern pitch can be reduced. Thus, the reliability and life characteristics of the entire substrate can be improved. In addition,
All or part of the outer insulating substrate contains resin of the above-mentioned material.
Because it is a soaked fiber sheet, the entire multilayer printed wiring board
Heat resistance and mechanical strength are improved.

The second invention (corresponding to claim 2) is the first invention
The surface of the heat-resistant organic sheet of the multilayer printed wiring board according to the present invention is provided with an adhesive layer for improving adhesiveness to the wiring pattern and / or another insulating substrate. Is a multilayer printed wiring board.

As described above, in the multilayer printed wiring board according to the second aspect of the present invention, since the adhesive layer is provided on the outermost insulating substrate, the outermost insulating substrate is separated from the wiring pattern and / or other insulating substrate. Adhesion with the substrate is improved, and high-density mounting of components on the multilayer printed wiring board can be realized.

A third aspect of the present invention (corresponding to claim 3) is the second aspect of the present invention.
Of the multilayer printed wiring board of the present invention, on the surface of the heat-resistant organic sheet before the adhesive layer is provided, in order to improve the adhesion between the heat-resistant organic sheet itself and the adhesive layer, A multilayer printed wiring board characterized by having irregularities formed by at least one of a corona discharge treatment, a plasma treatment, a flame treatment, an ultraviolet treatment, an electron beam / radiation treatment, and a sandblast treatment.

As described above, in the multilayer printed wiring board according to the third aspect of the present invention, the unevenness is formed on the surface of the heat-resistant organic sheet before the adhesive layer is provided. Adhesion with is improved.

According to a fourth aspect of the present invention (corresponding to claim 4), the first aspect
The heat-resistant organic sheet of the multilayer printed wiring board according to any one of the third to third aspects of the present invention is a wholly aromatic polyamide resin,
Multilayer print characterized by any one of a polyimide resin, a wholly aromatic polyester resin, a polycarbonate resin, a polysulfone resin, a tetrafluoroethylene resin, a hexafluoropropylene resin, a polyetheretherketone resin, and a polyphenyleneether resin It is a wiring board.

According to a fifth aspect of the present invention (corresponding to claim 5), the first aspect
The heat-resistant organic sheet of the multilayer printed wiring board according to any one of the fourth to fourth aspects of the present invention may be any one of Al ₂ O ₃ , TiO ₂ , Mg
A multilayer printed wiring board comprising 5% by volume to 45% by volume of an inorganic filler composed of one or a mixture of two or more of O and SiO ₂ .

As described above, the heat-resistant organic sheet of the multilayer printed wiring board according to the fifth aspect of the present invention contains 5% to 45% by volume of the inorganic filler as described above. And the mechanical strength and dimensional stability are improved.

According to a sixth aspect of the present invention (corresponding to claim 6), the first aspect
To the multilayer printed wiring board according to any one of the fifth to fifth aspects of the present invention.
The resin impregnated fiber sheet is made of glass epoxy composite,
A multilayer printed wiring board, which is one of a glass BT resin composite, an aramid epoxy composite, and an aramid BT resin composite.

[0026]

According to a seventh aspect of the present invention (corresponding to claim 7), a predetermined through-hole is formed in each of a plurality of insulating substrates including those made of a heat-resistant organic sheet, and a conductor is formed in the through-hole. Filling, laminating a metal foil on the surface of the insulating substrate, forming a wiring pattern using the metal foil, in the outermost layer, as the insulating substrate having the heat-resistant organic sheet as a constituent material is arranged, said plurality of insulating substrates pressurized adhered with heating by stacking, electrically connected to the wiring pattern by using the conductor, the outermost layer than
Resin impregnated fiber sheet on all or part of outer insulating substrate
A method for manufacturing a multilayer printed wiring board characterized by using the method.

According to an eighth aspect of the present invention (corresponding to claim 8), a predetermined through-hole is formed in each of a plurality of insulating substrates including those made of a heat-resistant organic sheet, and a conductor is formed in the through-hole. Filled, the insulating substrate having the heat-resistant organic sheet as a constituent material is disposed in the outermost layer, and the plurality of insulating substrates are stacked so that a wiring pattern is formed between each of the plurality of insulating substrates. A releasable support plate having a predetermined wiring pattern is arranged outside the outermost layer, and heated and pressed, and the wiring pattern of the releasable support plate is transferred to the heat-resistant organic sheet, and Adhering an insulating substrate, electrically connecting the wiring pattern using the conductor, then peeling off the releasable support plate , all or a part of the insulating substrate other than the outermost layer
A method for manufacturing a multilayer printed wiring board, comprising using a resin-impregnated fiber sheet . It is.

In the seventh and eighth methods of manufacturing a multilayer printed wiring board according to the present invention, since the surface of the outermost insulating substrate is smoothed and the wiring pattern is formed, the wiring pattern pitch is reduced. Can be
The reliability and life characteristics of the entire substrate can be improved. In addition, all or part of the insulating substrate other than the outermost layer
Since the resin impregnated fiber sheet of the above-mentioned material is used,
Improved heat resistance and mechanical strength of the entire printed wiring board
I do.

A ninth aspect of the present invention (corresponding to claim 9) is the seventh aspect of the present invention.
Alternatively, an adhesive layer for improving the adhesiveness with the wiring pattern and / or the other insulating substrate is provided on the surface of the heat-resistant organic sheet used in the method for manufacturing a multilayer printed wiring board according to the eighth aspect of the present invention. A method of manufacturing a multilayer printed wiring board, characterized by the following.

In the ninth method of manufacturing a multilayer printed wiring board according to the present invention, since the adhesive layer is provided on the outermost insulating substrate, the outermost insulating substrate and the wiring pattern and / or another insulating substrate are provided. And the adhesiveness with the adhesive can be improved.

According to a tenth aspect of the present invention (corresponding to claim 10),
Improving the adhesiveness between the heat-resistant organic sheet and the adhesive layer on the surface of the heat-resistant organic sheet used in the method of manufacturing a multilayer printed wiring board according to the ninth aspect before the adhesive layer is provided. Corona discharge treatment, plasma treatment, flame treatment, ultraviolet treatment, electron beam / radiation treatment,
A method for manufacturing a multilayer printed wiring board, characterized by forming irregularities by at least one of sandblasting processes.

According to the tenth method for manufacturing a multilayer printed wiring board of the present invention, the unevenness is formed on the surface of the heat-resistant organic sheet before the adhesive layer is provided. Is improved.

According to an eleventh aspect of the present invention (corresponding to claim 11),
The heat-resistant organic sheet used in the method for producing a multilayer printed wiring board according to any one of the seventh to tenth aspects of the present invention includes a wholly aromatic polyamide resin, a polyimide resin, a wholly aromatic polyester resin, a polycarbonate resin, a polysulfone resin, A method for manufacturing a multilayer printed wiring board, characterized by being one of a fluorinated polyethylene resin, a hexafluoropropylene resin, a polyetheretherketone resin, and a polyphenyleneether resin.

According to a twelfth aspect of the present invention (corresponding to claim 12),
The heat-resistant organic sheet used in the method for producing a multilayer printed wiring board according to any one of the seventh to eleventh aspects of the present invention is characterized in that:
5% by volume of an inorganic filler composed of one or a mixture of two or more of l ₂ O ₃ , TiO ₂ , MgO, and SiO ₂
A method for manufacturing a multilayer printed wiring board, characterized by containing about 45% by volume.

In the twelfth method of manufacturing a multilayer printed wiring board according to the present invention, a heat-resistant organic sheet containing 5% to 45% by volume of the above-mentioned inorganic filler is used. Can improve heat resistance, mechanical strength and dimensional stability.

According to a thirteenth aspect of the present invention (corresponding to claim 13),
The resin-impregnated fiber sheet used in the method for producing a multilayer printed wiring board according to any one of the seventh to twelfth aspects is a glass epoxy composite, a glass BT resin composite, an aramid epoxy composite, or an aramid BT resin composite. A method for producing a multilayer printed wiring board.

[0038]

[0039]

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

In the present embodiment, first, the multilayer printed wiring boards of Examples 1 to 5 will be described together with the method of manufacturing the same, and then, the results of comparison of predetermined characteristics between the multilayer printed wiring boards and the conventional multilayer printed wiring board will be described. .

[0041]

(Embodiment 1) First, FIG. 1 shows a sectional view of a multilayer printed wiring board according to Embodiment 1 of the present invention. In FIG. 1, reference numerals 11a and 11b denote heat-resistant organic sheets of the present invention. The heat-resistant organic sheets (insulating substrates) 11a and 11b are made of a wholly aromatic polyamide resin (Aramika). It is a sheet. 21
Is an insulating substrate of a resin-impregnated fiber sheet. Reference numerals 2 and 12 denote through holes provided at predetermined positions on the insulating substrate 11a, 11b or 21, and reference numerals 3 and 13 denote conductors filled in the through holes 2 or 12. 5a, 5b, 8a, 8
b is a wiring pattern formed on both surfaces of the insulating substrates 11a and 11b, and is electrically connected by the conductors 3 and 13.

Here, FIG. 2 shows the heat-resistant organic sheet 11 by unifying the reference number 11 to the heat-resistant organic sheets 11a and 11b described above. As shown in FIG. 3, the wiring pattern 5a, 5b, 8a or 8b or the insulating substrate 2 is provided on both surfaces of the heat-resistant organic sheet 11.
It is also possible to apply a heat-resistant adhesive 23a, 23b which has heat resistance and reinforces the adhesiveness with No. 1 and which does not substantially form irregularities on the surface when heated and pressed. It is. Further, the heat-resistant organic sheet 11 and the heat-resistant adhesives 23a, 23b are provided on the surface of the heat-resistant organic sheet 11 before the heat-resistant adhesives 23a, 23b are provided.
In order to improve the adhesiveness with, it is also possible to form irregularities by at least one of corona discharge treatment, plasma treatment, flame treatment, ultraviolet treatment, electron beam / radiation treatment, and sandblast treatment. .

Next, FIGS. 4 and 5 show a method of manufacturing the multilayer printed circuit board according to the first embodiment. Hereinafter, the manufacturing method will be described with reference to FIGS.

First, as shown in FIG. 4A, a release film 7 (16 μm thick) made of polyethylene terephthalate or the like is provided on both sides of the insulation substrate 21, and the insulation substrate 21 provided with the release film 7 is provided. In a predetermined location, a hole diameter of 200 μm was measured using a carbon dioxide laser from a laser processing machine.
Is formed. When a laser processing machine is used as described above, when a wiring pattern is formed later, the through hole 2 having a fine diameter corresponding to the miniaturization of the wiring pattern.
Can be formed easily and at high speed. As the insulating substrate 21, a non-woven fabric (180 μm thick) of aromatic polyamide (aramid) fiber (for example, “Kevlar” manufactured by DuPont, fineness: 1.5 denier, fiber length: 7 mm, basis weight: 70 g / m ² ) is used. Thermosetting epoxy resin (for example, Sh
A resin-impregnated fiber sheet made of an aramid epoxy composite impregnated with "EPON1151B60" manufactured by ell Co. was used.

Then, as shown in FIG. 4B, after the through-hole 2 is filled with a conductor 3 having a suitable viscosity and fluidity, such as a conductive paste or metal powder, the release film 7 is formed. Is peeled off. When a conductive paste is used as the conductor 3, a non-solvent type epoxy resin is used as a binder resin with a content of 90% by weight of copper powder having an average particle size of 2 μm, and this compound is rolled in three rolls. Mix uniformly with a kneader. In addition, as a method of filling the conductive paste 3 into the through-holes 2, a printing method of printing and applying a squeegee method or a roll transfer method from above the release film 7 is used. At this time, since the release film 7 functions as a print mask, the surface of the insulating substrate 21 is not contaminated by the conductive paste 3.

Next, as shown in FIG. 4C, metal foils each made of a copper foil 4 having a thickness of 35 μm are arranged on both surfaces of the insulating substrate 21, and a pressure of 60 kg / cm ² is applied in a vacuum. The temperature is raised from room temperature to 200 ° C. in 30 minutes,
After holding at 0 ° C. for 60 minutes, the temperature was lowered to room temperature in 30 minutes, thereby the insulating substrate 2 in the prepreg state was obtained.
1 and the conductive paste 3 are compressed and cured, and the copper foils 4 on both sides are adhered to the insulating substrate 21, and the copper foils 4 on both sides are electrically connected through the conductor 3 in the through hole 2. Obtain a substrate for a bonded circuit.

Next, as shown in FIG. 4D, the copper foil 4 is patterned by photolithography to form wiring patterns 5a and 5b, thereby obtaining a double-sided printed wiring board 6.

Next, as shown in FIG.
As in the case of the insulating substrate 21 described using (a), a release film 7 (16 μm thick) made of polyethylene terephthalate or the like was provided on both surfaces of the heat-resistant organic sheet 11, and the release film 7 was provided. A through hole 12 having a hole diameter of 200 μm is formed in a predetermined portion of the heat-resistant organic sheet 11 by a carbon dioxide laser or the like from a laser processing machine. By using a laser beam machine in this way, as described above, when forming a wiring pattern later, the through-hole 12 having a fine diameter corresponding to the miniaturization of the wiring pattern can be formed easily and at high speed. can do. In this example, a 30 μm-thick wholly aromatic polyamide resin (Aramika) sheet was used as the heat-resistant organic sheet 11. In order to increase the adhesive strength with the copper foil wiring patterns 5a and 5b of the double-sided printed wiring board 6 to be laminated later on both sides of the heat-resistant organic sheet 11, and the double-sided printed wiring board 6, etc. An adhesive having a thickness of rubber-modified epoxy resin was applied. However, as an alternative to the heat-resistant organic sheet 11 coated with an adhesive, a sheet having sufficient adhesive strength to the double-sided printed wiring board 6 and the copper foil with the wiring patterns 5a and 5b alone, for example, for printed wiring boards In the case of using a heat-fusible polyimide sheet or the like that can obtain a high adhesive force only by applying heat and pressure to a copper foil or the like, the application of the adhesive can be omitted.

Then, as shown in FIG.
After the through hole 12 is filled with a conductive material 13 such as a conductive paste or a metal powder having appropriate viscosity and fluidity in the same manner as the insulating substrate 21 described with reference to FIG. 7 is removed to obtain an intermediate connector 24.

Similarly, another such intermediate connector 24 is prepared. For convenience of the following description, the above-mentioned two intermediate connectors 24 are referred to as an intermediate connector 24a and an intermediate connector 24b.

Next, as shown in FIG.
The intermediate connectors 24a and 24b are arranged on both sides of the double-sided printed wiring board 6 of FIG.
Metal foils made of copper foils 4a and 4b each having a thickness of 35 μm are arranged outside of a and 24b, respectively, and are placed in a vacuum at 60 kg / cm.
^The temperature was raised from room temperature to 200 ° C. for 30 minutes while applying the pressure of ² , and kept at 200 ° C. for 60 minutes, then 30 minutes to room temperature.
Reduce temperature in minutes. Thus, the double-sided printed wiring board 6 is bonded to the intermediate connector 24a and the intermediate connector 24b, and further, the copper foils 4a and 4b are bonded to the intermediate connector 24a or the intermediate connector 24b.

Thereafter, as shown in FIG.
By patterning the copper foils 4a and 4b of (g) by photolithography, the wiring patterns 8a and 8b
Is formed to obtain a multilayer printed wiring board 25 having four wiring patterns.

(Embodiment 2) Next, a multilayer printed wiring board according to Embodiment 2 of the present invention will be described with reference to FIGS.

The multilayer printed wiring board according to the second embodiment is manufactured by changing the method of manufacturing the multilayer printed wiring board according to the first embodiment.

Hereinafter, a method of manufacturing the multilayer printed wiring board according to the second embodiment will be described with reference to FIGS.

First, as shown in FIG. 6A, as in the case of the first embodiment, a 12 μm thick release film 7 made of polyethylene terephthalate or the like is formed on both surfaces of the insulating substrate 1.
The through hole 2 having a hole diameter of 200 μm is formed in a predetermined portion of an insulating substrate 1 made of a resin-impregnated fiber sheet provided with a release film 7 by laser processing using a carbon dioxide laser or the like. The insulating substrate 1 has a thickness of 180 μm.
As the resin-impregnated fiber sheet, a resin-impregnated fiber sheet made of a porous prepreg obtained by impregnating an aromatic polyamide fiber with a thermosetting epoxy resin was used.

Then, as shown in FIG.
Then, the conductor 3 used for manufacturing the multilayer printed wiring board of Example 1 is filled, and then the release film 7 is peeled off to obtain the intermediate connector 20.

Next, as shown in FIG.
In the same manner as in (a), the heat-resistant organic sheet 11 has a thickness of 12 μm made of polyethylene terephthalate or the like on both surfaces.
And a through hole 12 having a hole diameter of 200 μm is formed in a predetermined portion of the heat-resistant organic sheet 11 provided with the release film 7 by laser processing using a carbon dioxide gas laser or the like.

Then, as shown in FIG.
2 is filled with a conductor 13 such as a conductive paste or a metal powder, and then the release film 7 is peeled off and removed.
Get 4.

Next, as shown in FIG. 6E, a metal foil made of a copper foil 14 having a thickness of 35 μm is arranged on both surfaces of the intermediate connector 24, and room temperature is applied while applying a pressure of 60 kg / cm ^{2 in} vacuum. Temperature to 200 ° C in 30 minutes,
After holding at 0 ° C. for 60 minutes, the temperature is lowered to room temperature in 30 minutes to compress and harden the insulating substrate 11 and the conductive paste 13 of the intermediate connector 24 and bond the copper foils 14 on both surfaces to the intermediate connector 24. Thus, a double-sided copper-clad circuit board is obtained in which the copper foils 14 on both sides are electrically connected via the conductor 13 in the through-hole 12.

Next, as shown in FIG.
Is patterned by a photolithographic method to form wiring patterns 16 and 17, thereby obtaining a double-sided printed wiring board 19.

Similarly, another such double-sided printed circuit board 19 is prepared. For convenience of the following description, the two double-sided printed circuit boards 19 are referred to as a double-sided printed circuit board 19a and a double-sided printed circuit board 19a.
b.

Next, as shown in FIG. 7 (g), the intermediate connector 20 is placed between two double-sided printed wiring boards 19a and 19b having different wiring patterns.
Is heated and pressurized from outside the double-sided printed wiring boards 19a and 19b to compress and cure the intermediate connector 20 in the prepreg state and the conductor 13 made of the conductive paste. Then, outer wiring patterns 17a and 17b and inner wiring patterns 16a and 16b as shown in FIG.
Printed wiring board 2 having four wiring patterns
Get 6.

(Embodiment 3) Next, a multilayer printed wiring board according to Embodiment 3 of the present invention will be described.

The multilayer printed wiring board according to the third embodiment is the same as the heat resistant organic sheet 11 of the multilayer printed wiring board according to the second embodiment.
Is completely the same as Example 2 except that the wholly aromatic polyamide resin sheet of Example 2 was changed to a thermosetting polyimide resin sheet (manufactured by Dupont Toray, Kapton), and the manufacturing method was described with reference to FIGS. The method for manufacturing a multilayer printed wiring board of Example 1 was used.

(Embodiment 4) Next, a multilayer printed wiring board according to Embodiment 4 of the present invention will be described.

The multilayer printed wiring board of the fourth embodiment is the same as the heat-resistant organic sheet 11 of the multilayer printed wiring board of the second embodiment.
Is completely the same as Example 2 except that the wholly aromatic polyamide resin sheet of Example 2 was changed to a wholly aromatic polyester resin sheet (manufactured by Kuraray, liquid crystal polymer). The manufacturing method is the same as that described with reference to FIGS. The method for manufacturing a multilayer printed wiring board of Example 1 was used.

(Embodiment 5) Next, a multilayer printed wiring board according to Embodiment 5 of the present invention will be described with reference to FIGS.

The difference between the multilayer printed wiring board of the fifth embodiment and the multilayer printed wiring board of the first embodiment is that the formation of wiring patterns is changed from a photolithographic method to a transfer method. Therefore, the steps of manufacturing the multilayer printed wiring board according to the fifth embodiment shown in FIGS. 4A to 4F are the same as those shown in FIG.

Next, as shown in FIG. 8A, first, both sides of the inner-layer double-sided printed wiring board 6 made of the resin-impregnated fiber sheet obtained in the same steps as in FIGS. 4A to 4D. 4A to 4F, an intermediate connector 24a made of a thermosetting polyimide resin (UPILEX manufactured by Ube Industries, Ltd.) in which the conductive paste 13 has been filled in the through holes 12 in advance, obtained in the same process as in FIGS. , 24b. Further, the releasable conductive support plate 2 in which wiring patterns 18a, 18b are respectively formed in advance outside the intermediate connectors 24a, 24b.
8a and 28b are arranged. Then, the conductive paste 13 is compressed and hardened by heating and pressing, and the wiring patterns 18a, 18b are applied via the adhesive applied to the surfaces of the heat-resistant organic sheets 11a, 11b of the intermediate connectors 24a, 24b, respectively. To the intermediate connector 24a,
24b. After the compression and curing reactions are completed, the release conductive support plates 28a and 28b are peeled off,
The heat-resistant organic sheets 11a, 1
A multilayer printed wiring board 27 having a four-layer wiring pattern whose outer surface is smoothed is obtained.

Comparative Example Next, in order to examine the performance of the multilayer printed wiring boards of Examples 1 to 5 of the embodiment of the present invention, a printed wiring board having a conventional all-layer IVH structure was manufactured as a comparative example. .

In the comparative example, the heat-resistant organic sheet 11 of the multilayer printed wiring board of Example 1 was changed to the same aramid nonwoven fabric as the insulating substrate 21 used for the inner layer of the multilayer printed wiring board. Is exactly the same as the multilayer printed wiring board of the second embodiment. The comparative example is obtained by the manufacturing method described in “Prior Art” with reference to FIGS.

(Comparative Results) Next, the results of measuring the electrical characteristics and the like of the multilayer printed wiring boards of Examples 1 to 5 of the embodiment of the present invention will be described in comparison with Comparative Examples.

The following points were measured for three samples of each of the multilayer printed wiring boards of Examples 1 to 5 and three samples of the comparative example.

First, a predetermined land having a diameter of 0.5 mm covering the through-hole on the outer surface of the outermost layer, and the land having a diameter of 0.5 m
m, and focus on another land similar to that land, and connect to each land with a width of 0.2 m.
A parallel wiring having a length of 15 mm and a length of 15 mm was provided, a DC potential was applied between the wirings, and a voltage at which the wiring caused dielectric breakdown was measured.

Further, by the perturbation method using a cavity rectilinear device,
The dielectric constant of the substrate is measured at normal temperature and normal humidity, and is measured at 60 ° C. and 95% RH.
Was left in the constant temperature / humidity bath for 250 hours and then taken out, and the dielectric constant was measured again to determine a change in the dielectric constant.

The wiring pattern provided on the outer surface of the outermost layer of each sample has a line width of 30 μm,
μm, 75 μm, and each line length is 1 μm.
The number of defects on the lines generated when 100 lines of 0 mm each were formed was determined.

Table 1 shows the above results.

[0079]

[Table 1]

As is clear from Table 1, the electrical characteristics and the formability of the fine wiring pattern of each example of the embodiment of the present invention are superior to those of the comparative example. In particular, the wiring pattern is formed by the transfer method. With regard to the line non-defective rate of Example 5 described above, it was possible to obtain a defect-free result even if the line width was as small as 30 μm.

In each of the above embodiments, the case where a wholly aromatic polyamide resin, a thermosetting polyimide resin, or a wholly aromatic polyester resin is used as the material of the heat resistant organic sheet has been described. As the material of the resin, polycarbonate resin, polyphenylene ether resin, polysulfone resin, polyethylene tetrafluoride resin, 6
The same effect can be obtained by using a fluorinated polypropylene resin, a polyetheretherketone resin, or the like.

Further, although an example in which an aramid epoxy composite is used as the resin-impregnated fiber sheet described in each of the examples has been described, the above-described case where a glass epoxy composite, a glass BT composite, or an aramid BT composite is used instead of the aramid epoxy composite is also used. A printed wiring board similar to that of the embodiment can be obtained.

Further, as the heat-resistant organic sheet in each of the above embodiments, Al ₂ O ₃ , TiO _2
2 , a heat-resistant organic sheet containing 5% to 45% by volume of an inorganic filler made of one or a mixture of two or more of MgO and SiO ₂ may be used. In this case, the heat resistance, mechanical strength, and dimensional stability of the heat-resistant organic sheet are improved.

[0084]

As is apparent from the above description, according to the present invention, when a heat-resistant organic sheet is used as an outer layer substrate of a multilayer printed wiring board having an all-layer IVH structure, heat resistance, moldability, and smoothness are improved. In addition, the adhesiveness of the wiring pattern to the insulating substrate is improved, and a short circuit between the wiring patterns due to the conductive paste oozing into the porous base material during compression in the manufacturing process can be prevented. At the same time, a finer wiring pattern can be formed by utilizing the high smoothness of the heat-resistant organic sheet surface.
Furthermore, by utilizing the excellent electric insulation performance and good tracking resistance of the heat-resistant organic sheet, a highly reliable printed wiring board suitable for high-density mounting can be obtained at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view of a multilayer printed wiring board according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the heat-resistant organic sheet used in the multilayer printed wiring board of Example 1 of the embodiment of the present invention in FIG.

FIG. 3 is a partially enlarged cross-sectional view of a heat-resistant organic sheet having adhesive layers provided on both sides.

FIG. 4 is a process chart showing a method for manufacturing a first half of a multilayer printed wiring board according to Example 1 of the embodiment of the present invention;

FIG. 5 is a process chart showing the latter half of the method of manufacturing the multilayer printed wiring board according to the first embodiment of the present invention;

FIG. 6 is a process chart showing a method for manufacturing a first half of a multilayer printed wiring board according to a second embodiment of the present invention;

FIG. 7 is a process chart showing the latter half of the method for manufacturing the multilayer printed wiring board according to the second embodiment of the present invention;

FIG. 8 is a process chart showing the latter half of the method for manufacturing a multilayer printed wiring board according to Example 5 of the embodiment of the present invention;

FIG. 9 is a process diagram showing a first half of a method of manufacturing a conventional multilayer printed wiring board having an all-layer IVH structure.

FIG. 10 is a process chart showing a method for manufacturing the latter half of a conventional multilayer printed wiring board having an all-layer IVH structure.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Insulating substrate, support body 2, 2a, 2b, 12 Through-hole, via hole 3, 3a, 3b, 13 Conductor, conductive paste, conductive paste 4, 4a, 4b, 14 Copper foil 5a, 5b, 8a, 8b , 16, 16a, 16b, 1
7, 17a, 17b, 18a, 18b Wiring pattern 6, 19, 19a, 19b Double-sided printed wiring board, double-sided wiring board 7 Release film 9 Four-layer wiring board 11, 11a, 11b Heat-resistant organic sheet, insulating substrate 20, 20a, 20b Intermediate connector 21 Resin impregnated fiber sheet, insulating substrate 23a, 23b Heat resistant adhesive 24, 24a, 24b Intermediate connector 25, 26, 27 Multilayer printed wiring board 28a, 28b Releasable conductive support plate

──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yasuhiro Nakaya 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-8-181450 (JP, A) JP-A-9-237972 (JP, A) JP-A-7-176846 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H05K 3/46

Claims (13)

(57) [Claims] An insulating substrate laminate including a plurality of insulating substrates having a through hole and a conductor embedded in the through hole, between the plurality of insulating substrates, and between the insulating substrate laminates disposed on at least one surface of the outer surface, the a wiring pattern connected by the conductive member, at least the outermost layer, wherein the wiring pattern on both sides are disposed the insulating substrate constituting material Ri heat resistant organic sheet der ,Previous
All or part of the insulating substrate other than the outermost layer is resin impregnated
A multilayer printed wiring board, which is a fiber sheet . 2. The heat-resistant organic sheet is provided on its surface with an adhesive layer for improving adhesion to the wiring pattern and / or another insulating substrate. 2. The multilayer printed wiring board according to 1. 3. The surface of the heat-resistant organic sheet before the adhesive layer is provided is provided with a corona discharge treatment, a plasma treatment, and a plasma treatment to improve the adhesiveness between the heat-resistant organic sheet itself and the adhesive layer. The multilayer printed wiring board according to claim 2, wherein the unevenness is formed by at least one of a treatment, a flame treatment, an ultraviolet treatment, an electron beam / radiation treatment, and a sandblast treatment. 4. The heat-resistant organic sheet is made of a wholly aromatic polyamide resin, a polyimide resin, a wholly aromatic polyester resin, a polycarbonate resin, a polysulfone resin, a polytetrafluoroethylene resin, a hexafluoropropylene resin, a polyetheretherketone resin. The multilayer printed wiring board according to any one of claims 1 to 3, wherein the multilayer printed wiring board is any one of a polyphenylene ether resin. 5. The heat-resistant organic sheet is made of Al ₂ O ₃ , T
iO _2, MgO, multilayer printed circuit according to claims 1, characterized in that it comprises an inorganic filler composed of one or more kinds of mixture of SiO ₂ 5 vol% to 45 vol% in any of 4 substrate. 6. The resin impregnated fiber sheet according to claim 1, wherein the fiber sheet is any one of a glass epoxy composite, a glass BT resin composite, an aramid epoxy composite, and an aramid BT resin composite. The multilayer printed wiring board according to the above. 7. A predetermined through hole is formed in each of a plurality of insulating substrates including a heat resistant organic sheet as a constituent material, a conductive material is filled in the through holes, and a metal foil is coated on the surface of the insulating substrate. Attaching, forming a wiring pattern by using the metal foil, and laminating the plurality of insulating substrates and heating so that an insulating substrate having the heat-resistant organic sheet as a constituent material is disposed on the outermost layer. Pressing and bonding, electrically connecting the wiring pattern using the conductor, and applying a resin to all or a part of the insulating substrate other than the outermost layer
A method for producing a multilayer printed wiring board, comprising using an impregnated fiber sheet . 8. A predetermined through hole is formed in each of a plurality of insulating substrates including a heat resistant organic sheet as a constituent material, and the through hole is filled with a conductor. The plurality of insulating substrates are stacked so that an insulating substrate to be arranged is disposed in an outermost layer, and a wiring pattern is formed between each of the plurality of insulating substrates, and further has a predetermined wiring pattern outside the outermost layer. The releasable support plate is arranged and heated and pressed, and the wiring pattern of the releasable support plate is transferred to the heat-resistant organic sheet, and the plurality of insulating substrates are adhered to each other using the conductor. To electrically connect the wiring pattern, then peeling off the releasable support plate, the insulating substrate other than the outermost layer
A method for manufacturing a multilayer printed wiring board, wherein a resin-impregnated fiber sheet is used in whole or in part . 9. An adhesive layer for improving the adhesiveness to the wiring pattern and / or the other insulating substrate is provided on the surface of the heat-resistant organic sheet. Of manufacturing a multilayer printed wiring board. 10. A corona discharge treatment, a plasma treatment, and the like, on the surface of the heat-resistant organic sheet before the adhesive layer is provided, in order to improve the adhesion between the heat-resistant organic sheet and the adhesive layer. Flame treatment, UV treatment, electron beam
The method according to claim 9, wherein the unevenness is formed by at least one of a radiation treatment and a sandblast treatment. 11. The heat-resistant organic sheet is made of a wholly aromatic polyamide resin, a polyimide resin, a wholly aromatic polyester resin, a polycarbonate resin, a polysulfone resin, a polytetrafluoroethylene resin, a hexafluoropolypropylene resin,
The method for manufacturing a multilayer printed wiring board according to any one of claims 7 to 10, wherein the method is one of a polyether ether ketone resin and a polyphenylene ether resin. 12. The heat-resistant organic sheet is made of Al ₂ O ₃ ,
TiO _2, MgO, multilayer printed circuit according to any one of claims 7 to 11, characterized in that it comprises an inorganic filler composed of one or more kinds of mixture of SiO ₂ 5 vol% to 45 vol% Substrate manufacturing method. 13. The resin-impregnated fiber sheet according to claim 7, wherein the resin-impregnated fiber sheet is any one of a glass epoxy composite, a glass BT resin composite, an aramid epoxy composite, and an aramid BT resin composite. A method for manufacturing the multilayer printed wiring board according to the above.