JP2003008200A - Wiring board and its producing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayer wiring board and its producing method employing a conductor, e.g. conductive paste, for interlayer electrical connection in which highly reliable fine via holes are realized. SOLUTION: Via holes 104 opened in the thickness direction of an electric insulating basic material 102 are filled with conductive paste 105 to form wiring layers 107 in a specified pattern on the opposite sides of the electric insulating basic material, and the wiring layers are connected electrically with conductive paste. In such a wiring board, surface roughness on the side abutting against the electric insulating basic material of at least one wiring layer is set not larger than the mean particle size of conductive particles contained in the conductive paste. Since only the resin component in the conductive paste is discharged and conductive particles in the conductive paste are left in the via holes, the conductive paste is made compact, thus realizing highly reliable via hole connection having low initial resistance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board for electrically connecting layers with a conductive paste and a method for manufacturing the wiring board.

[0002]

2. Description of the Related Art In recent years, a multilayer wiring board has been devised for electrically connecting layers by using a conductive paste. For such a wiring board, for example, Japanese Patent Laid-Open No. 11-12696.
No. 8 publication. FIG. 2 is a diagram showing a method of manufacturing the multilayer wiring board.

First, as shown in FIG. 2 (a), a thickness of 0.6
18 μm thick on both sides of the glass epoxy base material 204 of mm
A hole is made in the double-sided copper-clad laminate to which the copper foil 201 is attached, plated copper 202 is formed by electroless copper plating, and unnecessary copper is removed by etching to form an inner layer circuit 205. Subsequently, a thermosetting resin 203 is applied to the holes by silk screen printing, the holes are filled, and after heating and curing, the resin protruding from the holes is removed by polishing to form an inner layer substrate.

Next, as shown in FIG. 2 (b), the thickness is 18 μm.
55 μm thick epoxy adhesive layer 2 on one side of copper foil of m
The resin-coated copper foil 206 provided with 07 is placed on both sides of the inner layer substrate and heated and pressed to be laminated and integrated.

After the etching resist films are laminated on both sides of the laminated substrate prepared in the previous step, the via holes are opened by exposure and development, and copper is removed by etching to form the via hole openings 208. As shown in c), the etching resist film is peeled off and removed.

Next, a carbon dioxide impact laser machine is used to irradiate a laser on the location of the via hole opening 208 to remove the insulating adhesive 207 and reach the inner layer circuit 205, as shown in FIG. 2 (d). A via hole 209 having a diameter of 0.15 mm is formed.

Subsequently, as shown in FIG. 2E, the conductive paste 210 is filled in the via holes 209 by a silk screen printing method using a squeegee.

Subsequently, as shown in FIG. 2 (f), the substrate filled with the conductive paste 210 is vacuum filled with a degree of vacuum of 1.0 × 1.
It is placed in a vacuum chamber 211 of 0 ⁻⁶ Pa and left for 5 minutes to remove residual air during print filling.

After that, as shown in FIG. 2 (g), the conductive paste 210 is heated and hardened, and then, as shown in FIG. 2 (h), the metal foil 206 is removed by etching in a predetermined pattern to form an exterior circuit. 212 is formed to form a multilayer wiring board.

[0010]

However, in the above-described manufacturing method, when the via hole is made fine, the variation in the initial connection resistance value becomes large, and the reliability test such as the temperature cycle test and the pressure cooker test is performed. Therefore, there is a problem that the connection resistance value changes. This is because if the via hole is made fine, it becomes difficult to print and fill the conductive paste, and even if the remaining air is removed by the vacuum chamber, a sufficient amount of the conductive paste for connection cannot be secured in the via hole.

In view of the above problems, it is an object of the present invention to provide a wiring board and a method of manufacturing the wiring board, which are capable of realizing a fine via hole having high connection reliability by using a conductive paste. .

[0012]

In order to solve the above problems, in the wiring board of the present invention which is the first invention, a conductive paste is filled in a via hole opened in the thickness direction of an electrically insulating base material. A wiring board in which a wiring layer having a predetermined pattern is formed on both surfaces of the electrically insulating base material, and the wiring layers are electrically connected by the conductive paste, wherein at least one of the wiring layers is electrically connected. The surface roughness of the side in contact with the insulating base material is less than or equal to the average particle diameter of the conductive particles contained in the conductive paste.

As a result, even when a compressive force is applied to the conductive paste during filling of the conductive paste or heating and pressurization for curing the electrically insulating base material, only the resin component in the conductive paste comes out of the via hole. Since the conductive particles in the conductive paste that have been discharged remain in the via holes, the conductive paste is densified, the initial resistance value is low, and highly reliable via hole connection is possible.

Further, in the wiring board of the present invention, it is preferable that at least one of the wiring layers has a molten layer at a portion where the wiring layer contacts the conductive paste.

Thus, since the molten layer is provided in the wiring layer portion at the bottom of the via hole, in order to improve the adhesion to the electrically insulating base material such as the nickel layer and the chromate layer which are usually provided on the surface layer of the wiring layer. Since the metal oxide layer of 1 is melted and only the bottom of the via hole is removed, the connectivity with the conductive paste is further improved, the initial resistance value is low, and the via hole connection having high reliability is easily obtained.

Next, according to the method of manufacturing a wiring board of the present invention, the wiring layer is formed in a predetermined pattern and the surface roughness of which is less than the average particle diameter of the conductive particles contained in the conductive paste. A step of laminating an insulating base material, a step of forming a via hole reaching the wiring layer in the electrically insulating base material, a step of filling the conductive paste in the via hole, and a step of forming the via hole through the surface of the wiring layer. Discharging the resin component contained in the conductive paste, densifying the conductive paste filled in the via hole, and heating and pressurizing the electrically insulating base material laminated on the wiring layer. And a step of embedding the wiring layer in the electrically insulating base material.

As a result, even when a compressive force is applied to the conductive paste during filling of the conductive paste or heating and pressurization for curing the electrically insulating substrate, only the resin component in the conductive paste is removed from the via hole. Since the conductive particles in the conductive paste that have been discharged remain in the via holes, the conductive paste is densified, the initial resistance value is low, and a highly reliable wiring substrate capable of connecting via holes is obtained.

Further, in the method for manufacturing a wiring board of the present invention, in the step of forming a via hole reaching the wiring layer in the electrically insulating substrate, the via hole is formed by laser irradiation, and the wiring irradiated with the laser is formed. It is preferred to form a molten layer on the layer.

As a result, the molten layer can be formed only on the bottom of the via hole.

Further, in the method for manufacturing a wiring board of the present invention, in the step of densifying the conductive paste filled in the via hole, the step of filling the conductive paste in the via hole is repeated a plurality of times. It is preferable that the resin component contained in the conductive paste is discharged through the surface of the wiring layer.

As a result, the resin component in the conductive paste can be further discharged through the surface of the wiring layer, so that the conductive paste can be densified during printing more effectively by a simple process. .

Next, the multilayer wiring board of the present invention which is the second invention is a multilayer wiring board in which two or more electrically insulating base materials having via holes in the thickness direction filled with a conductive paste are laminated. A wiring layer having a predetermined pattern is formed between the electrically insulating substrates, and at least one of the wiring layers existing on both sides of the insulating substrate has the electrically insulating property. The surface roughness of the side in contact with the base material is less than or equal to the average particle diameter of the conductive particles contained in the conductive paste.

This makes it possible to provide a highly reliable multilayer wiring board having fine via holes.

Further, the multilayer wiring board of the present invention is characterized in that at least one of the wiring layers has a molten layer at a portion where the wiring layer contacts the conductive paste.

As a result, a more reliable via hole can be realized.

Further, in the method for manufacturing a multilayer wiring board according to the present invention, the wiring layer formed in a predetermined pattern and having a surface roughness not larger than the average particle diameter of the conductive particles contained in the conductive paste is electrically connected. A step of laminating an insulating base material, a step of forming a via hole reaching the wiring layer in the electrically insulating base material, a step of filling the conductive paste in the via hole, and a step of forming the via hole through the surface of the wiring layer. Discharging the resin component contained in the conductive paste, densifying the conductive paste filled in the via hole, and heating the electrically insulating substrate laminated on the wiring layer.
The step of applying pressure and embedding the wiring layer in the electrically insulating base material is repeated.

This makes it possible to provide a highly reliable multilayer wiring board having fine via holes.

Further, in the method for manufacturing a multilayer wiring board of the present invention, in the step of forming a via hole reaching the wiring layer in the electrically insulating substrate, the via hole is formed by laser irradiation, and the laser is irradiated. It is preferable to form a molten layer on the wiring layer.

As a result, it is possible to obtain a multilayer wiring board in which the molten layer is formed only on the bottom of the via hole.

Further, in the method for manufacturing a multilayer wiring board of the present invention, in the step of densifying the conductive paste filled in the via hole, a plurality of steps of further filling the conductive paste in the via hole are performed. It is preferable that the resin component contained in the conductive paste is discharged through the surface of the wiring layer.

As a result, the resin component in the conductive paste can be further discharged through the surface of the wiring layer, and a simple method for manufacturing a multilayer wiring board can be provided.

[0032]

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

(Embodiment 1) FIG. 1 is a process sectional view showing a method of manufacturing a double-sided wiring board according to a first embodiment of the present invention.

First, as shown in FIG. 1 (a), an electrically insulating substrate 102 having release films 103 formed on both surfaces thereof.
To prepare.

Here, as the electrically insulating base material 102,
An organic resin film 1020 having excellent dimensional stability and high heat resistance with the adhesive layer 101 formed on both sides is used. Examples of the organic resin film 1020 include a polyimide film and an aramid film. Polyimide films include Kapton (Toray DuPont), Upilex (Ube Industries), Apical (Kanebuchi Kagaku), and the like, which are characterized by low water absorption. Aramid films include Aramika (Asahi Kasei) and Miktron (Toray), which are characterized by having higher rigidity and less elongation than polyimide films.

A thermosetting adhesive or a thermoplastic adhesive is used as the adhesive layer 101. Examples of thermosetting adhesives include epoxy adhesives and polyimide adhesives. Further, as the thermoplastic adhesive, for example, a silicon-based high heat-resistant grade adhesive may be mentioned. When a thermosetting resin is used, it is preferable that the thermosetting resin be in a semi-cured state in order to secure the filling property of the wiring layer.

As the release film 103, a film which absorbs a laser beam used for hole processing is preferably used. For example, when a carbon dioxide gas laser having a wavelength of 2 μm is used as the laser light, a polyethylene terephthalate (PET) film having an absorption band at the wavelength is used, and an excimer laser having a wavelength of 307 nm or a wavelength of 355 n is used.
When an ultraviolet laser such as a YAG solid laser having a triple harmonic of m is used, a polyethylene naphthalate (PEN) film having an absorption band at the wavelength may be used.

In this embodiment, the organic resin film 1
A polyimide film having a thickness of about 12 μm was used as 020, a thermosetting polyimide resin was used as the adhesive layer 101, and a PEN film having a thickness of 12 μm was used as the release film 103. The polyimide resin was applied and dried in order to secure the pattern embedding property and left in a semi-cured state. The thickness of the adhesive layer was 5 μm on each side.

Next, as shown in FIG. 1B, the electrically insulating base material 102 having the release films 103 formed on both surfaces thereof.
While removing the release film 103 on one side, the supporting substrate 106 provided with the wiring layer 107 formed in a predetermined shape
They are stacked on top of each other and laminated at a temperature of about 80 ° C.
As a result, the surface of the adhesive layer 101 is slightly melted and can be attached to the wiring layer 107 and the supporting base material 106. Further, the surface layer of the wiring layer 107 is roughened and is slightly buried in the adhesive layer 101 even after lamination, but since the lamination temperature is 80 ° C., which is lower than the softening temperature of the resin, all the roughened surfaces are It has not reached the level of embedding, and the roughened surface on the upper surface of the wiring layer 107 and the adhesive layer 10
A gap 109 was observed between 1 and 1.

Next, as shown in FIG. 1C, a via hole 104 is formed at a predetermined position of the wiring layer 107 by laser from the side of the release film 103. Here, as the laser, an excimer laser with a wavelength of 307 nm or a wavelength of 3
A short wavelength laser such as a 55 nm triple harmonic YAG solid state laser can be used. In this embodiment, the via hole 104 having a hole diameter of about 50 μm is formed by an ultraviolet laser. At this time, no resin residue was observed on the bottom surface of the hole, but in the ultraviolet laser, the resin component is chemically decomposed because the processing by ablation is the main processing rather than the processing by heat. Further, the gap 109 between the roughened surface on the wiring layer 107 and the adhesive 101 was also maintained.

By adjusting the laser energy and the energy distribution during processing, the roughened surface at the bottom of the via hole can be melted while leaving the gap 109. It is considered that the gap 109 remains because the copper foil forming the wiring layer 107 has good thermal conductivity and the heat energy during heating is immediately lost. As described above, when the molten layer is provided in the portion in contact with the conductive paste, it is possible to obtain a highly reliable via hole with a lower connection resistance.

Generally, a rust preventive layer formed of a metal oxide such as chromate is present on the copper foil. However, since this rust preventive layer usually does not have conductivity, a conductive paste as in this embodiment is used. When making a connection, the rust preventive layer is made as thin as possible to form an island shape, and the connection is made at a portion without the rust preventive layer. Therefore, by forming the molten layer, the rustproof layer is removed and the connection area is increased, so that a via hole with low resistance and good connection reliability can be obtained. Even in this case, the gap 109 can be maintained by appropriately selecting the laser conditions, so that the air and the resin component seep out through the gap, and the conductive particles can be densified.

Further, when forming fine wiring,
As the electric insulating layer 102, it is preferable to select a material that allows the wiring layer 107 to be seen through the electric insulating layer.
This makes it possible to perform laser hole processing while recognizing the wiring layer 107.

Next, as shown in FIG. 1D, the via hole 104 is filled with a conductive paste 105. The filling is
The conductive paste 105 was directly printed on the release film 103 by a screen printer. At this time, it was observed that the resin component of the conductive paste 105 exudes from the gap 109. By providing the gap 109 in this way, even when the conductive paste 105 is pushed in from the upper surface of the via hole 104, the air inside escapes from the gap 109, so that good filling can be achieved. The gap 109 is set to be smaller than the average particle size of the conductive particles in the conductive paste 105. Therefore, the structure is such that the resin component exudes but the conductive particles do not come out.
Such a structure can be realized by setting the roughness of the roughened surface on the wiring layer 107 to be smaller than the average particle size of the conductive particles in the conductive paste 105. Further, since the resin component is sucked out by the capillarity, only the resin component can be sucked out without performing an operation such as pressurization from the top surface.

In this example, copper powder having an average particle size of 5 μm was used as the conductive particles. This is determined in consideration of the filling property because the diameter of the via hole is 50 μm. The roughness of the roughened surface of the wiring layer 107 was 3 μm. The gap 109 at this time was about 2 μm. This is because when the electrically insulating substrate 102 is laminated, the roughened surface of the copper foil is slightly embedded in the electrically insulating substrate 102. In this example, the conductive particles having the above size and the roughness of the roughened surface were used, but the present invention is not particularly limited to the above, and if the roughness of the roughened surface is smaller than the size of the conductive particles. The resin component in the conductive paste 105 is discharged through the gap 109, but the conductive particles do not flow out.

As described above, since the air in the via hole 104 is discharged through the gap 109, a good filling can be obtained even once, but the conductive paste is further densified. Filled twice. The reason for the densification is that a part of the resin component is discharged from the via hole 104 by the first filling, and the second filling is performed when the volume is reduced.
This is because the ratio of conductive particles in 04 is higher than that of the conductive paste before printing.

Next, as shown in FIG. 1 (e), the release film 103 is peeled off. The release film 103 also serves to prevent contamination of the surface of the adhesive layer 101 by the conductive paste 105. At this time, the via hole 104 is 50 μm
Since it is fine, the influence of the end portion cannot be ignored, and the conductive paste in the via hole is taken off together with the release film 103. The conductive paste 105 remains in various ways, but is not scooped below the surface of the adhesive layer 101, and the adhesive layer 101 is worn out at worst. The phenomenon that the conductive paste is removed by the release film 103 becomes remarkable when the pore diameter is 100 μm or less.

Next, as shown in FIG. 1 (f), the metal foil 10
8 are superposed on the electrically insulating base material 102 from above and heated and pressed. In this example, a copper foil was used as the metal foil and was heated and pressed by a vacuum press. The heating and pressurizing conditions are temperature 2
It was carried out at 00 ° C. and a pressure of 100 to 200 kg / cm ² . The present conditions are not limited to the above, and the adhesive layer 10
It is determined in consideration of the curing condition of No. 1, embeddability, compressibility of conductive particles, and the like.

By this heating and pressing, as shown in FIG. 1G, the adhesive layer 101 flows and the wiring layer 107 is embedded in the adhesive layer 101. By thus embedding the wiring layer 107 in the adhesive layer 101, the via hole 1
The conductive paste 105 in 04 is compressed, the resin component in the conductive paste 105 flows out to the adhesive layer 101,
The conductor component in the conductive paste 105 is densified, and electrical connection between the wiring layers 107 on the front and back of the insulating base material 102 is obtained. Then, the adhesive layer 101 and the conductive paste 105
Hardens.

Next, as shown in FIG. 1 (h), the copper foil 108
Is patterned into a predetermined shape.

Finally, as shown in FIG. 1 (i), the supporting base material 106 is removed, leaving the wiring layer 107 embedded in the adhesive layer 101, and the double-sided wiring board is completed. In this embodiment, an aluminum foil is used for the supporting base 106 and a copper foil is used for the wiring layer 107. The support base 106 is removed by selectively removing the aluminum foil and the copper foil by dissolving and removing the aluminum foil. In this way, by removing the supporting base material 106 by dissolution and removal, stress is not applied to the double-sided wiring substrate to break it, and the double-sided wiring substrate can be removed in a consistent line, so productivity is improved.

Here, hydrochloric acid or the like can be used as the selective etching solution. In addition, in the process mentioned above, the aluminum foil support base material 106 provided with the copper foil wiring layer 107.
Was laminated with the electrically insulating substrate 102, but the same method can be used also when forming the copper foil wiring layer 107 in a predetermined pattern. In this case, ammonium persulfate or the like can be used as the selective etching solution.

As a composite material of aluminum foil and copper foil,
For example, Mitsui Kinzoku Co., Ltd. copper foil UT with aluminum carrier
C-Foil etc. are mentioned. In this composite material, since the thickness of the copper foil is as thin as 5 μm or 9 μm, it is possible to form a fine pattern. Further, a similar composite material can be obtained by forming a resist pattern on the aluminum foil in advance, performing an acidic zincate treatment, and then performing electrolytic copper plating. By the method by electrolytic plating, a fine pattern and a thick copper foil can be obtained. With this method, a line width of 10 μm, a space of 10 μm and a copper foil thickness of 15 μm can be obtained.

In the above embodiment, the insulating base material 102 is used.
As an adhesive layer 1 on both sides of the organic resin film 1020
The release film 103 is provided with 01.
The adhesive layer 101 may be provided on the insulating base material 102 to be attached to the insulating base material 102 to form a similar structure. By adopting such a manufacturing method, the adhesive layer 101 can be applied to one side of the release film 103 and dried to a semi-cured state. Therefore, the adhesive layer 101 is applied to both sides of the organic resin film 1020 at the same time. Then, the adhesive layer 101 can be formed on both surfaces of the insulating base material 102 more easily than the method of drying to a semi-cured state.

Although FIG. 1 of the above-described embodiment shows the structure in which the wiring layer 107 covers the via hole 104, it is not necessary to cover all the part of the via hole 104. Since the conductive paste may be embedded so that a predetermined compression ratio can be obtained between the wiring layers in the via hole, it is sufficient to cover a part of the via hole. That is, a part of the via hole may be exposed as long as the conductive paste of the via hole is overlapped so as to be compressed in the wiring layers provided above and below. For example, in the present embodiment, if a via hole having a diameter of 50 μm and a wiring of 30 μm are used, the conductive paste is compressed and an electrical connection between wiring layers can be obtained. With such a configuration, so-called lands are unnecessary, and finer wiring can be formed. In particular, the above configuration is effective when applied to the inner layer of the multilayer wiring board.

In the above embodiment, the case where the adhesive layers are provided on both sides of the organic resin film as the electrically insulating substrate has been described, but the present invention is not limited to this.

For example, a composite material obtained by impregnating a woven cloth with a semi-cured thermosetting resin can be used as the electrically insulating substrate. As such a composite material, there is a glass epoxy prepreg obtained by impregnating a glass woven cloth with an epoxy resin. As a result, the glass woven cloth becomes a wall in the heating and pressing step, and the pressing force is applied in the thickness direction, so that the resin component in the conductive paste can be more effectively discharged, and a more precise via hole can be obtained. be able to. Further, since the same glass epoxy prepreg as that used in the conventional glass epoxy wiring board can be used, the wiring board can be easily manufactured.

As the electrically insulating base material, a composite material in which a non-woven fabric is impregnated with a thermosetting resin in a semi-cured state can be used. As such a composite material, there is an aramid epoxy prepreg obtained by impregnating an aramid nonwoven fabric with an epoxy resin. As a result, the aramid non-woven fabric becomes a wall in the heating and pressing step, and the pressure is applied in the thickness direction, so that the resin component in the conductive paste can be more effectively discharged, and a more precise via hole can be obtained. You can Further, since the aramid epoxy prepreg has a larger amount of shrinkage in the thickness direction than the glass epoxy prepreg, it is possible to obtain a more precise via hole.

As the electrically insulating base material, a composite material obtained by impregnating a semi-cured thermosetting resin into a porous film can be used. As such a composite material, there is a porous prepreg obtained by impregnating a polyimide porous film with an epoxy resin. Thereby, the polyimide porous film becomes a wall in the heating and pressurizing step, and the pressing force is applied in the thickness direction, so that the resin component in the conductive paste can be more effectively discharged, and a more dense via hole can be formed. Obtainable. Further, since the porous prepreg has a larger amount of shrinkage in the thickness direction than the glass epoxy prepreg, it is possible to obtain a more precise via hole. The pore size of the porous film is set smaller than that of the conductive particles. As a result, only the resin component in the conductive paste is discharged from the holes, and the conductive particles do not leak from the via holes.

When a multilayer wiring board is produced using the manufacturing method of the present invention, the above steps may be repeated. In this case, the supporting base material 106 may be removed each time, but it is easier to stack the supporting base material 106 on the supporting base material 106 and finally remove it. Moreover, since the dimensional change after stacking is suppressed by removing it last, it is possible to suppress the positional deviation in the case of a high multilayer structure, and design with a fine design rule.

[0061]

As described above, in the wiring board of the present invention, the via holes opened in the thickness direction of the electrically insulating base material are filled with the conductive paste, and both surfaces of the electrically insulating base material are provided with a predetermined amount. The wiring layer formed in the pattern of is a wiring substrate electrically connected by the conductive paste, the surface roughness of at least one of the wiring layer abutting the electrically insulating substrate is Since the average particle diameter of the conductive particles in the conductive paste is equal to or smaller than the average particle diameter, the resin component contained in the conductive paste is discharged from the via hole when the conductive paste is filled. for that reason,
The conductor component of the conductive paste is densified, the initial resistance value is low, and highly reliable fine via hole connection can be realized. Further, also when a plurality of wiring boards of the present invention are laminated, similarly, a multilayer wiring board having highly reliable and fine via holes can be realized. Therefore, its industrial value is great.

[Brief description of drawings]

FIG. 1 is a process sectional view showing a method of manufacturing a double-sided wiring board according to a first embodiment of the present invention.

FIG. 2 is a process cross-sectional view showing a filling method for a conventional multilayer wiring board.

[Explanation of symbols]

101 adhesive layer 102 electrical insulating base material 103 Release film 104 beer hall 105 conductive paste 106 supporting substrate 107 wiring layer 108 metal foil 1020 Organic resin film 201 copper foil 202 plated copper 203 thermosetting resin 206 metal foil 207 Insulating adhesive layer 209 beer hall 210 Conductive paste 211 vacuum chamber 212 outer layer circuit

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05K 3/46 H05K 3/46 N X (72) Inventor Hideki Higashiya 1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric Sangyo Co., Ltd. F-term (reference) 5E317 AA24 BB02 BB03 BB12 CD27 GG16 5E343 AA07 AA13 AA17 AA18 BB24 BB67 BB72 DD02 GG11 5E346 AA12 AA15 AA43 CC04 CC09 CC10 CC41 DD12 DD32 EE31 FF18 GG15 GG27 H31

Claims (10)

[Claims] 1. A via hole opened in a thickness direction of an electrically insulating base material is filled with a conductive paste, wiring layers having a predetermined pattern are formed on both surfaces of the electrically insulating base material, and the wiring layers are provided between the wiring layers. A wiring board electrically connected by a conductive paste, wherein the surface roughness of at least one of the wiring layers on the side in contact with the electrically insulating substrate is a conductive material contained in the conductive paste. A wiring substrate having an average particle diameter of the conductive particles or less. 2. The wiring board according to claim 1, wherein at least one of the wiring layers has a molten layer at a portion where the wiring layer contacts the conductive paste. 3. A step of laminating an electrically insulating base material on a wiring layer which is formed in a predetermined pattern and whose surface roughness is equal to or less than the average particle diameter of the conductive particles contained in the conductive paste, Forming a via hole reaching the wiring layer in the electrically insulating substrate, filling the conductive paste in the via hole, and a resin component contained in the conductive paste through the surface of the wiring layer. Discharging and densifying the conductive paste filled in the via hole; heating and pressurizing the electrically insulating base material laminated on the wiring layer to form the wiring layer on the electrically insulating base material. And a step of embedding the wiring board. 4. The step of forming a via hole reaching the wiring layer in the electrically insulating base material, the via hole is formed by laser irradiation, and a molten layer is formed on the laser-irradiated wiring layer. A method for manufacturing a wiring board according to. 5. In the step of densifying the conductive paste filled in the via hole, the step of filling the conductive paste in the via hole is performed a plurality of times, and the conductive layer is formed through the surface of the wiring layer. The method for manufacturing a wiring board according to claim 3, wherein the resin component contained in the paste is discharged. 6. A multilayer wiring board in which two or more electrically insulating base materials having a via hole in a thickness direction filled with a conductive paste are laminated, and a predetermined pattern is provided between the electrically insulating base materials. The wiring layer is formed, and the surface roughness of at least one of the wiring layers present on both sides of the insulating base material on the side in contact with the electrically insulating base material is the conductivity. A multilayer wiring board, characterized in that the average particle diameter of the conductive particles contained in the paste is not more than the average particle diameter. 7. The multilayer wiring board according to claim 6, wherein at least one of the wiring layers has a molten layer at a portion where the wiring layer contacts the conductive paste. 8. A step of laminating an electrically insulating base material on a wiring layer which is formed in a predetermined pattern and whose surface roughness is equal to or less than the average particle diameter of the conductive particles contained in the conductive paste, Forming a via hole reaching the wiring layer in the electrically insulating substrate, filling the conductive paste in the via hole, and a resin component contained in the conductive paste through the surface of the wiring layer. Discharging and densifying the conductive paste filled in the via hole; heating and pressurizing the electrically insulating base material laminated on the wiring layer to form the wiring layer on the electrically insulating base material. A method for manufacturing a multilayer wiring board, characterized in that the step of burying is repeated. 9. The step of forming a via hole reaching the wiring layer in the electrically insulating substrate, the via hole is formed by laser irradiation, and a molten layer is formed on the laser-irradiated wiring layer. A method for manufacturing the multilayer wiring board according to. 10. The step of densifying the conductive paste filled in the via hole, the step of filling the conductive paste in the via hole is performed a plurality of times, and the conductive layer is formed through the surface of the wiring layer. The method for manufacturing a multilayer wiring board according to claim 8, wherein the resin component contained in the paste is discharged.