JP2002359466A - Multilayered wiring board and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high realiability multilayered wiring board that can prevent deterioration of its characteristics, even if the board is kept in a high- temperature and high-humidity environment for a long time, by preventing the infiltration of moisture through the interfaces between conductor wiring layers and insulation layers or from insulation resin by improving the chemical affinity between the wiring layers and insulation layers. SOLUTION: This multilayered wiring board has the insulation layers 1 containing at least a thermosetting resin, the conductor wiring layers 2 embedded in the surfaces of the insulation layers 1, and via conductors 3 formed by packing a conductor component containing metallic powder in through-holes for connecting the wiring layers 2 to each other. In the wiring board, a coupling agent 4 is installed on the surfaces of the wiring layers 2, which are in contact with the via conductors 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer wiring board suitable for, for example, a multilayer wiring board and a package for accommodating a semiconductor device, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, electronic devices have been reduced in size.
In recent years, with the development of portable information terminals and the spread of so-called mobile computing in which a computer is carried and operated, there is a tendency that a smaller, thinner, and higher-definition multilayer wiring board is required.

[0003] Further, electronic devices that require high-speed operation, such as communication devices, have been widely used. The requirement for high-speed operation includes various requirements such as accurate switching of high-frequency signals. In order to cope with such electronic devices, a multilayer printed wiring board suitable for high-speed operation is required.

In order to perform high-speed operation, it is necessary to reduce the length of wiring and shorten the time required for transmitting an electric signal. In order to reduce the length of the wiring, there is a tendency for a small, thin, and high-definition multilayer wiring substrate in which the width of the wiring is reduced and the gap between the wirings is reduced.

In order to meet such a demand for high-density wiring, a manufacturing method called a build-up method is used. The basic structure of the build-up method is classified into two types in the JPCA standard: (1) base + build-up method and (2) all-layer build-up method.

(1) In the base + build-up method, a photosensitive resin is applied to the surface of a core substrate in which a conductor wiring layer and a through-hole conductor are formed on the surface of an insulating substrate such as a double-sided copper-clad glass epoxy substrate, and then exposed. After forming a through hole, apply a plating layer such as copper on the entire surface of the photosensitive insulating layer, apply a photosensitive resist to the plating layer, expose and develop the circuit pattern, and form a non-resist After forming a circuit by etching a portion, the resist is removed to form a conductor wiring layer, and this process is repeated to form a multilayer.

[0007] (2) A method of manufacturing an all-layer build-up is to form a through-hole in an insulating sheet by a laser or the like and fill a conductive paste in the through-hole as disclosed in Japanese Patent No. 2587593, for example. The conductor wiring layers formed on the surface of the insulating sheet are electrically connected to form a wiring sheet, and the wiring sheet thus produced is repeatedly formed to be multilayered.

[0008]

However, (1)
In the base + build-up method, photosensitive epoxy resin is often used as an insulating sheet. However, the epoxy resin originally has a low glass transition point and is made photosensitive to increase the water absorption rate. There is a problem that reliability decreases, such as deterioration of reliability. Therefore, a resin having a lower water absorption than an epoxy resin such as an allylated polyphenylene ether (A-PPE) resin or BT resin is used. However, since a resin having a low water absorption has a lower polarity, wettability with a highly polar metal surface is low. As a result, the interface between the insulating layer and the conductor wiring layer is weakened, which makes it very easy to pass moisture and the like which cause deterioration of characteristics. In particular, when the pitch of the via conductors is narrowed, the insulation resistance between the via conductors decreases, and when the diameter of the through-hole is reduced, the problem such as an increase in the resistance of the via conductors appears remarkably. This has been a major obstacle for manufacturing a wiring board.

Further, the core substrate surface has irregularities corresponding to the thickness of the conductor wiring layer formed of copper foil, and the photosensitive resin used in the build-up method is in a liquid state. Was reflected on the surface of the multilayer wiring layer that was built up, and irregularities were also formed on the surface of the finished product, which was unsuitable for mounting on a silicon chip such as a flip chip. Also,
In a temperature cycle test or a high-temperature / high-humidity test, peeling was likely to occur at the interface between the core substrate and the insulating layer of the buildup layer.

Various solutions to the above problem have been proposed, and are described in Electronics Packaging Technology Magazine 1998, 1 (V
ol. 14 No. 1) describes a smooth build-up substrate obtained by transferring a circuit pattern formed on a stainless steel plate by a pattern plating method using a lamination press. However, the chemical bonding between the core substrate and the insulating resin of the build-up layer has not been improved, and there has been a problem in reliability.

In the above (2) all-layer build-up method, a via conductor is formed by filling a conductive paste into a through-hole, but the via conductor is oxidized in a reliability test such as high-temperature storage or PCT. There is a problem that electric resistance increases. Further, when the pitch between the via conductors is reduced, there is a problem that the insulation resistance between the via conductors is reduced. This is because the interface between the conductor wiring layer or the via conductor and the insulating resin is weak, and those that cause deterioration of moisture and the like are easy to pass through. Further, it is considered that the moisture is generated because the moisture that has passed through the resin directly enters the inside of the via conductor.

An object of the present invention is to solve the above-mentioned problems in the conventional multilayer wiring board. Specifically, the present invention increases the chemical affinity between a conductive wiring layer and an insulating layer, and A highly reliable multilayer wiring board that prevents moisture from entering from the interface between the wiring layer and the insulating layer or moisture from the insulating resin and has no characteristic deterioration even in a long-time high-temperature, high-humidity environment. It is an object of the present invention to provide a method for manufacturing a multilayer wiring board that can be easily manufactured.

[0013]

According to the present invention, there is provided a multilayer wiring board comprising at least an insulating layer containing a thermosetting resin, a conductive wiring layer buried on the surface of the insulating layer, and a through-hole for connecting the conductive wiring layers. In a multilayer wiring board having a via conductor filled with a conductor component containing a metal powder in a hole, a coupling agent is present on a surface of a conductor wiring layer in contact with the via conductor.

Further, according to the method for manufacturing a multilayer wiring board of the present invention, (a) a step of adhering a metal foil to a resin film via an adhesive, and (b) the resin film produced by (a) After forming a wiring pattern resist on the surface, performing an etching process to form a conductor wiring layer on the resin film surface, and then removing the pattern resist; and (c) forming the resist on the resin film formed by (b). Applying a coupling agent to the upper surface of the conductor wiring layer of
(D) forming a through hole in a B-stage insulating sheet containing at least a thermosetting resin by laser light, filling a conductive paste containing metal powder to form a via conductor, and forming an insulating sheet; , (E) (a) ~
(C) laminating and pressurizing the conductor wiring layer on the surface of the resin film formed on the surface of the insulating sheet prepared in (d), and then removing the resin film and transferring the conductor wiring layer; f) laminating another insulating sheet having a via conductor and / or a wiring conductor layer on the insulating sheet produced in (e), and curing the whole while applying pressure. is there.

Further, in the above-described multilayer wiring board and the method for manufacturing the same, the thermosetting resin has a water absorption of 0.1%.
The following is desirable in order to suppress the water absorption of the wiring board, and the conductor wiring layer can be made fine wiring and low resistance by processing a metal foil. The coupling agent present on the surface of the conductor wiring layer in contact with the via conductor is preferably of a silicon type, so that it is easy to apply to a copper foil and has a large effect of preventing moisture from entering. When the thickness of the coupling agent present on the surface of the conductor wiring layer in contact with the via conductor is 10 to 100 nm, the electrical connection reliability between the copper foil and the via conductor and the invasion of moisture can be effectively prevented. it can.

According to the multilayer wiring board of the present invention, since the conductor wiring layer is embedded so as to be flush with the surface of the insulating layer, the surface of the multilayer wiring board is excellent in smoothness. Further, in the multilayer wiring board of the present invention, since the surface of the conductor wiring layer in contact with the via conductor is coated with the coupling agent, intrusion of moisture into the via conductor from the interface between the conductor wiring layer and the via conductor, By lowering the water absorption of the insulating resin, the penetration of moisture from the insulating resin can be prevented,
Even when the pitch of the via conductors becomes narrower, it is possible to obtain a high-density and high-reliability multilayer wiring board in which the insulation resistance between the via conductors does not deteriorate and the resistance of the via conductors does not increase.

According to the manufacturing method of the present invention, since the through holes for connecting the conductor wiring layers in the multilayer wiring layer are formed by laser irradiation, there is no need to use a photosensitive resin, and the insulating layer is not required. As the material, an arbitrary insulating material having a high glass transition point and excellent material properties such as a low water absorption can be selected. Further, since the surface of the conductor wiring layer in contact with the via conductor is coated with the coupling agent, it is possible to prevent moisture from entering the inside of the via conductor. In addition, the formation of the insulating sheet and the formation of the conductor wiring layer can be performed simultaneously in parallel, and all the insulating sheets can be cured at a time, thereby simplifying and shortening the manufacturing process. it can.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A multilayer wiring board according to the present invention will be described with reference to the drawings together with a manufacturing method. FIG. 1 is a schematic diagram for explaining a multilayer wiring board according to the present invention.

According to the multilayer wiring board of FIG. 1, a plurality of insulating layers 1 containing at least a thermosetting resin are laminated, and a conductor wiring layer 2 is buried on the surface of the insulating layers 1. . In the inside of the insulating layer 1, a via conductor 3 is formed in which a through-hole is filled with a conductor component containing a metal powder in order to connect between conductor wiring layers 2 formed between different layers.

According to such a multilayer wiring board, FIG.
As described in the main part enlarged cross-sectional view, the coupling agent 4 is present at the connection portion between the conductor wiring layer 2 and the via conductor 3. According to the present invention, the presence of the coupling agent 4 suppresses the infiltration of moisture into the inside of the via conductor 3 even in a high-temperature, high-humidity environment for a long period of time, so that a highly reliable multilayer without the resistance deterioration of the via conductor 3 is provided. A wiring board is obtained.

The coupling agent is microscopically assumed to be present between the conductive wiring layer 2 and the metal particles in a structure in which the metal particles forming the via conductor 3 are in contact with each other. The thickness of the coupling agent, that is, the thickness at which the coupling agent exists microscopically at the interface between the conductor wiring layer 2 and the via conductor 3 is 10 to 100 nm, particularly 2
It is suitably from 0 to 80 nm, and the thickness is 10 nm.
If it is smaller than 100 nm, the effect is low, and if it is larger than 100 nm, the electrical connection between the conductor wiring layer 2 and the via conductor 3 may be hindered.

Further, in order to improve the moisture resistance of the multilayer wiring board, the water absorption of the thermosetting resin forming the insulating layer 1 is set to 0.1.
It is desirable that the content be 1% or less, particularly 0.08% or less.

Next, a method of manufacturing the above-mentioned multilayer wiring board will be described with reference to the process chart of FIG. First, FIG.
As shown in (a), the metal foil 11 is bonded to the surface of the resin film 12 via an adhesive. At this time, it is desirable to use a copper foil as the metal foil 11 in consideration of the ease of forming the wiring thereafter, electric resistance, and the like. Then, a photoresist 13 is further attached to the surface of the metal foil 11 (b). And
By exposing and developing the photoresist 13, the photoresist 14 is left on the conductor wiring portion (c). When the photoresist 14 is of a negative type, the processing is easier to perform when the subsequent conductor wiring layer 15 is roughened. Thereafter, the conductor wiring layer 15 is formed by etching the metal foil 11 (d). At this time, the cross section of the conductor wiring layer 15 formed on the surface of the resin film 12 is preferably formed in a trapezoidal shape.
As for the formation angle of the trapezoid, (θ) is preferably 45 ° to 80 °, and more preferably 50 ° to 75 °. If the formation angle of the trapezoid is smaller than 45 °, the peel strength of the conductor wiring layer 15 will decrease when a multilayer wiring board is manufactured thereafter. If the angle of formation of the trapezoid is larger than 80 °, the length of the side surface of the conductor wiring layer 15 becomes short, so that moisture reaches the via conductor 18 quickly and the resistance rises quickly. The trapezoidal formation angle (θ) is 45 ° to 80 °
It depends on the type of the metal foil 11 to make
It is preferable to perform etching at about 50 μm / min.

Then, by cleaning and removing the photoresist 14, the conductor wiring layer 15 can be formed on the surface of the resin film 12 (e).

It is desirable that the surface of the conductor wiring layer 15 formed on the resin film 12 be roughened. In particular, by roughening the surface roughness (Ra) to 0.2 μm or more, the adhesion between the conductor wiring layer 15 and an insulating sheet 16 described later can be further increased. Although it differs depending on the type of metal, it is preferable to spray or dipping an acidic solution such as formic acid, NaClO ₂ , NaOH, Na ₂ PO ₄ or a mixture thereof, and it is particularly preferable to spray formic acid to reduce the surface roughness. It is desirable because it can be finely controlled.

Next, a coupling agent is applied to the upper surface of the conductor wiring layer 15 on the resin film 12 which is to be in contact with a via conductor 18 described later. As the coupling agent, a silicon-based coupling agent can be suitably used. The thickness of the coupling agent is 10 to 100 nm, preferably 20 to 80 n.
m is desirable. Coupling agent thickness is 10
If it exceeds 0 nm, when the coupling agent itself is an insulator, the electrical connection resistance with the via conductor 18 increases. When the thickness of the coupling agent is less than 10 nm, the effect of applying the coupling agent is small.

The thickness of the coupling agent can be easily adjusted depending on the concentration of the coating solution. Specifically, although slightly different depending on the type of the coupling agent, 0.5 to
10-1 solution diluted with 10% aqueous solution or alcohol
It can be as thick as 00 nm. By using a silicon-based coupling agent, it is easy to apply it to a copper foil, and it is possible to effectively prevent intrusion of moisture. Specifically, silane coupling agents such as N-phenyl-γ-aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, and N-β (aminoethyl) γ-aminopropyltrimethoxysilane are preferably used. Although it can be used, other silane coupling agents can exert sufficient effects. The coupling agent having a boiling point of 250 ° C. or higher can be suitably used. If the boiling point is 250 ° C. or less, swelling occurs at the interface between the conductor wiring layer 15 and the insulating resin in a solder heat resistance test or the like, and the resistance of the via conductor 18 increases.

On the other hand, as shown in FIG. 2F, first, an insulating sheet 16 is prepared. This insulating sheet 16 is made of a thermosetting resin and an inorganic filler. The thermosetting resin constituting the insulating sheet 16 preferably has a water absorption of 0.1% or less, and more preferably 0.08% or less. If the water absorption of the thermosetting resin is higher than 0.1%, the resistance of the via conductor 18 increases due to the influence of moisture. Specifically, A
-PPE (allylated polyphenylene ether), BT resin (bismaleimide triazine), polyimide resin,
At least one selected from the group of polyamide bismaleimides, particularly A-PPE, is most desirable. In addition, since epoxy resin etc. have a large water absorption, they are not suitable for use in a high-temperature, high-humidity atmosphere.

The inorganic filler of the insulating sheet 16 is as follows:
SiO ₂ , Al ₂ O ₃ , AlN and the like are preferable, and the filler has an average particle diameter of 20 μm or less, particularly 10 μm or less.
Most preferably, a substantially spherical powder of 7 μm or less is used. Further, in order to provide the strength of the multilayer wiring board, it is preferable to use a fibrous woven or nonwoven fabric. At least one layer is preferably formed of an insulating sheet 16 containing a fibrous filler. The inorganic filler is mixed in a volume ratio of organic resin: inorganic filler of 15:85 to 95: 5.
In order to reduce the via pitch for producing a high-density wiring board, it is desirable to use a spherical filler rather than a fibrous filler.

Next, the insulating sheet 1 is irradiated with a laser beam.
The through hole 17 of No. 6 is processed (f). The processing of the through hole 17
CO ₂ , YAG laser, excimer laser and the like are suitable. Thereafter, a binder is added to a metal powder containing at least one selected from gold, silver, copper, aluminum, and the like to prepare a conductor paste. Then, a conductive paste is filled into the through holes 17 to form via conductors 18 (g). It is desirable to use a binder which is nonvolatile and reacts with the insulating resin. A normal pressure printing machine or the like can also be used as a method for filling the conductive paste, but using a vacuum printing machine can further increase the filling rate.

Thereafter, a resin film 12 having a pattern of a mirror image of the conductor wiring layer 15 is laminated on the surface of the insulating sheet 16 on which the via conductors 18 are formed (h), 3 kg / c.
After applying a pressure of at least m ² , the resin film 12 is peeled and transferred (i), whereby the wiring sheet 15 in which the conductor wiring layer 15 is connected to both ends of the via conductor 18 formed in the insulating sheet 16 is provided. A can be obtained (j).

Then, another wiring sheet having via conductors 18 and / or conductive wiring layers 15 is separately laminated on the wiring sheet 19. At this time, wiring sheet 1
9 is positioned as the internal conductor wiring layer of the multilayer wiring board, and the surface opposite to the surface connected to the via conductor 18 is also connected to the via conductor of another wiring sheet. The coupling agent is also applied to the exposed surface of the conductor wiring layer 15 embedded on the surface of the sheet 19.

For example, as shown in FIG. 2 (k), the via conductor 18
Are formed, and a wiring sheet A in which the conductor wiring layers 15 are formed on both ends thereof and a wiring sheet B in which only the via conductors 18 are formed in the insulating sheet 19 are prepared. By laminating with -BA, a multilayer structure having six conductor wiring layers can be formed.
In such a case, it is necessary to apply a coupling agent to both sides of the conductor wiring layer to be the internal conductor wiring layer.

Thereafter, the laminated body of (k) is cured at once to form an insulating layer 1, a conductor wiring layer 2, a via conductor 3, a via conductor 3 and a conductor wiring layer 2 as shown in FIG.
A multilayer wiring board having the coupling agent 4 at the interface can be manufactured.

According to the present invention, since a coupling agent is interposed between the conductor wiring layer and the via conductor, penetration of moisture into the inside of the via conductor can be suppressed. In addition, it is possible to obtain a highly reliable multilayer wiring board in which the resistance of the via conductor does not deteriorate and the insulation between the via conductors does not deteriorate. Further, in the manufacturing method, since the processing of the conductor wiring layer and the processing of the insulating layer can be performed in parallel on each layer, and the multilayered insulating resin can be cured at a time, the multilayer wiring board can be formed in a short cycle time. Can be made.

[0036]

EXAMPLE As an insulating sheet, allylated polyphenylene ether resin (A-PPE) or BT resin was used.
Further, spherical silica was used as the inorganic filler, and these were used as an A-PPE resin or a composition in which the BT resin: inorganic filler had a volume ratio of 50:50, and this was insulated in a B-stage state having a thickness of 40 μm by a doctor blade method. A sheet was prepared.

A through hole of 100 μmφ or 50 μmφ was formed on each of these insulating sheets with a CO ₂ laser, and then a powder having a copper surface coated with silver was mixed with a binder. Was prepared.

On the other hand, 12 μm
An electrolytic copper foil having a thickness of m was attached to prepare a film with a copper foil for transfer. A dry film resist is stuck on the copper foil surface, exposed, developed with sodium carbonate, and etched with ferric chloride to form a trapezoidal formation angle of 45 ° to 80 °.
The conductor wiring layer having the formation angle of was formed. Thereafter, the resist was stripped off with sodium hydroxide to form a wiring pattern on the PET film. Thereafter, the surface of the conductive wiring layer was roughened to Ra 0.4 μm with 10% formic acid.

Then, 1-20% of N-phenyl-γ-aminopropyltrimethoxysilane or N-β (aminoethyl) γ-aminopropyltrimethoxysilane is appropriately formed on the surface of the conductor wiring layer in contact with the via conductor. An aqueous solution of the coupling agent was applied and dried at 120 ° C. to form a layer of the coupling agent having a thickness of 10 to 150 nm. In addition, the sample No. As No. 1, a coating that did not apply anything to the surface of the conductor wiring layer was prepared.

Next, the conductor wiring layer formed on the PET film was transferred to both surfaces of the above-mentioned two types of insulating sheets at 130 ° C. and 20 kg / cm ² to prepare a wiring sheet A. In the wiring sheet A, an inner conductor wiring layer,
The same coupling agent as described above was coated on the exposed surface of the conductor wiring layer connected to other via conductors.

Then, the wiring sheet A and the wiring sheet B having no conductive wiring layer were laminated in the order of ABABA in this order to produce a multilayer wiring board having six conductive wiring layers. Thereafter, all the insulating sheets were simultaneously cured at 200 ° C. and 20 kg / cm ² to produce a multilayer wiring board.

As a multilayer wiring board, 800 wiring conductors having a diameter of 100 μm were formed for evaluation of continuity, and a daisy chain in which these were connected in series by a wiring layer was prepared. ,
As shown in Table 2, a wiring board in which via conductors of 100 μmφ or 50 μmφ were formed at via pitches of 150 to 250 μm, respectively, was manufactured.

The following evaluation was performed on the manufactured wiring board. First, a cured 50 mm × 50 mm laminate obtained by laminating 10 layers of 100 μm-thick insulating sheets was dried at 50 ° C. for 24 hours, and then immersed in 23 ° C. water using the insulating material used to manufacture the wiring board. The weight difference was evaluated as the water absorption.

In the continuity evaluation, 15 evaluation samples were used.
0 ° C, 1000 hours high temperature storage test, 130 ° C, humidity 8
5%, 2.3atm, 200 hours pressure PCT
The test was performed. Before and after the above test, the daisy chain having a resistance change of 10% or less was tested as a good product and the one with a resistance change exceeding 10% as a defective product, and tested for 20 N-numbered wiring boards.

In evaluating the insulation, a bias of 5.5 V was applied between the via conductors at 130 ° C. and 85% RH to perform a high-temperature and high-humidity bias test.
After 96 hours, a product with a resistance of 10 ⁸ Ω or more is a non-defective product and 10 ⁸ Ω
The following were tested as defectives on 20 N wiring boards. Table 1 shows the results of the continuity evaluation, and Table 2 shows the results of the insulation evaluation.

[0046]

[Table 1]

[0047]

[Table 2]

As shown in Tables 1 and 2, the presence of the coupling agent on the surface of the conductor wiring layer in contact with the via conductor does not increase the resistance even in a high-temperature storage test or a PCT test. Also in the test, a high-density multilayer wiring board without insulation deterioration was able to be manufactured.
In addition, in the multilayer wiring board of the present invention, the processing of the insulating layer and the processing of the conductor wiring layer can be performed in parallel, and the resin of the insulating layer can be collectively cured, so that the cycle time can be greatly reduced.

[0049]

As described in detail above, according to the present invention,
Obtain a multilayer wiring board that is excellent in flatness of the substrate surface, prevents oxidation of via conductors due to moisture, improves reliability of conductive wiring layers, and is suitable for flip-chip mounting of semiconductor elements. Can be.

Further, according to the manufacturing method of the present invention, the processing of the insulating layer and the processing of the conductor wiring layer can be performed in parallel as compared with the conventional build-up method and the like, and the resin of the insulating layer can be cured at once. The cycle time can be significantly reduced.

[Brief description of the drawings]

FIG. 1A illustrates a multilayer wiring board according to the present invention.
It is a schematic diagram, and (b) The principal part expanded sectional view.

FIG. 2 is a process diagram illustrating an example of a method for manufacturing a multilayer wiring board according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating layer 2 Conductor wiring layer 3 Via conductor 4 Coupling agent 11 Metal foil 12 Resin film 13, 14 Photoresist 15 Conductor wiring layer 16 Insulating sheet 17 Through hole 18 Via conductor 19 Wiring sheet

Claims (9)

[Claims] An insulating layer containing at least a thermosetting resin,
In a multilayer wiring board comprising a conductor wiring layer buried on the surface of the insulating layer and a via conductor filled with a conductor component containing a metal powder in a through hole for connecting the conductor wiring layers, a conductor contacting the via conductor A multilayer wiring board, wherein a coupling agent is present on the surface of the wiring layer. 2. The multilayer wiring board according to claim 1, wherein the thermosetting resin has a water absorption of 0.1% or less. 3. The multilayer wiring board according to claim 1, wherein the conductive wiring layer is formed by processing a metal foil. 4. The multilayer wiring board according to claim 1, wherein the coupling agent present on the surface of the conductive wiring layer in contact with the via conductor is a silicon-based coupling agent. 5. The multilayer wiring board according to claim 1, wherein the thickness of the coupling agent present on the surface of the conductor wiring layer in contact with the via conductor is 10 to 100 nm. 6. A step of: (a) adhering a metal foil to a resin film via an adhesive; and (b) forming a wiring pattern resist on the surface of the resin film prepared in (a), followed by etching. To form a conductive wiring layer on the surface of the resin film, and then removing the patterned resist, and applying a coupling agent to the upper surface of the conductive wiring layer on the resin film formed by (c) and (b). Process and
(D) forming a through hole in a B-stage insulating sheet containing at least a thermosetting resin by laser light, filling a conductive paste containing metal powder to form a via conductor, and forming an insulating sheet; , (E) (a) ~
(C) laminating and pressing the conductor wiring layer on the surface of the resin film formed on the surface of the insulating sheet formed on the surface of the insulating sheet prepared in (d), and then peeling off the resin film to transfer the conductor wiring layer; f) laminating another insulating sheet having a via conductor and / or a wiring conductor layer on the insulating sheet prepared in (e), and curing at once while applying pressure; Substrate manufacturing method. 7. The method according to claim 6, wherein the thermosetting resin has a water absorption of 0.1% or less. 8. The method according to claim 6, wherein the coupling agent coated on the surface of the conductor wiring layer in contact with the via conductor is a silicon-based coupling agent. 9. The method for manufacturing a multilayer wiring board according to claim 6, wherein a coupling agent is applied to the surface of the conductive wiring layer in contact with the via conductor in a thickness of 10 to 100 nm. .