JP2002359469A - Wiring board, manufacturing method therefor, and electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable wiring board, in which wiring conductors and through-conductors can be jointed surely to each other and no peeling occurs in junctions over a long time, even when thermal stresses are repetitively impressed upon the sections, and to provide a method of manufacturing the wiring board and an electronic device. SOLUTION: The wiring board 5 is constituted by alternately laminating plural insulation layers 1 and wiring conductors 2 upon another and electrically connecting the wiring conductors 2 to each other through the through-conductors 4 which are formed by packing conductors in through-holes 3 bored through the insulation layers 1. The wiring conductors 2 are composed of electroless- plated copper layers formed on the insulation layers 1 and electroplated copper layers, formed on the electroless-plated copper layers or copper foil provided on the insulation layer 1. The through-conductors 4 are composed of electroplated copper layers or electroplated copper formed on the copper foil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring board in which a through conductor filled with a conductor is made of electrolytic copper plating, a method of manufacturing the same, and an electronic device. In particular, it is an object of the present invention to provide a highly reliable wiring board that can reliably join a wiring conductor and a through conductor and that does not peel off at a connection portion even when a long-term thermal stress is repeatedly applied, a method of manufacturing the same, and an electronic device. is there.

[0002]

2. Description of the Related Art In general, current electronic devices are required to be small, thin, lightweight, high-performance, high-performance, high-quality, and high-reliable, as represented by mobile communication devices. Electronic devices mounted on various electronic devices have also been required to be reduced in size and density. For this reason, there has been a demand for smaller, thinner, and more terminals for the wiring boards that make up the electronic device, and in order to achieve this, the width of wiring conductors such as signal conductors has been reduced and the spacing between them has been reduced. High-density wiring has been achieved by increasing the number of wiring conductors.

As a wiring board capable of such high-density wiring, a wiring board manufactured by employing a build-up method is known. The build-up wiring board is, for example, a core material obtained by impregnating a thermosetting resin typified by an epoxy resin having heat resistance and chemical resistance into a reinforcing material such as glass cloth or aramid non-woven cloth, and then curing the core with an epoxy. After applying a varnish made of a thermosetting resin such as a resin and heating and curing to form an insulating layer, the diameter of the insulating layer is 50 to 200 μm by laser.
About through holes, then chemically roughen the inner wall of the through holes and the surface of the insulating layer with a rough solution such as a potassium permanganate solution, and then use electroless copper plating and electrolytic copper plating. A copper conductor film is applied to the inner wall of the through hole and the surface of the insulating layer to form a through conductor and a wiring conductor. Further, the same steps as above are repeated on the insulating layer to form a plurality of insulating layers, wiring conductors, and through holes. It is manufactured by forming a conductor.

Further, in order to further increase the density of the build-up wiring board, a method of reducing the width and spacing of the wiring conductors and a method of reducing the diameter of the through hole to reduce the spacing have been performed. Are stacked in the vertical direction to form a stacked via structure.

In this stacked via structure, in order to arrange the through conductors in the vertical direction and electrically connect them, it is necessary to fill the inside of the through holes with copper plating to form a filled via structure.

As a method of forming a filled via structure in which the inside of the through hole is filled with copper plating, a method of adding a leveling agent to a plating solution, a PRC method (Pulsed Reversed Curing).
nt method). The method of adding a leveling agent to the plating solution is to apply a leveling agent to deposit copper plating on the inner wall of the through hole while suppressing the growth of the electrolytic copper plating layer on the surface of the insulating layer, and electrolytic copper plating the inside of the through hole. It is a method of filling. In addition, the PRC method is a pulse plating method in which the negative and positive values of the electrolytic copper plating current are reversed at a constant cycle.When the current is positive, the copper plating layer dissolves, so the current is concentrated. In this method, copper plating is prevented from growing on the protrusions and copper plating is preferentially applied to the inner walls of the through holes in the recesses. As a result, the inside of the through holes is filled with electrolytic copper plating.

[0007]

However, in the method of adding a leveling agent to a plating solution, electroless copper plating is always required as a base electrode in order to fill the through holes by electrolytic copper plating. A bonding surface between the electrolytic copper plating and the electroless copper plating is generated on the through conductor. Electrolytic copper plating, the particle size is larger than the particle size of the electroless copper plating and the density is high, so the bonding strength with the electroless copper plating is low, and in a stacked via structure in which through conductors are arranged vertically, If a long-term thermal stress is repeatedly applied, it will peel off at the joint between electroless copper plating and electrolytic copper plating. As a result, there has been a problem that the peeling extends to a connection portion between the through conductor and the wiring conductor, and the through conductor and the wiring conductor are disconnected. Furthermore, while the thermal expansion coefficient of the electrolytic copper plating of the through conductor is about 18 ppm / ° C., the thermal expansion coefficient in the thickness direction of the insulating layer is 80 to 200 ppm.
/ ° C, a large thermal stress occurs due to a difference in thermal expansion between the penetrating conductor and the insulating layer. In the temperature cycle test, the penetrating conductor and the insulating layer are separated, and as a result, a break occurs inside the penetrating conductor. Had the problem that

[0008] In addition to the problems described above, the PRC method requires a longer plating time due to the complicated plating method, and requires a more expensive apparatus than a power supply apparatus used in ordinary electrolytic copper plating. There was a problem that it became necessary.

The present invention has been completed in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a stacked via structure in which a wiring conductor and a through conductor can be reliably joined and a through conductor is vertically arranged. An object of the present invention is to provide a highly reliable wiring board which does not peel off at a connection portion even when thermal stress is repeatedly applied, a method of manufacturing the same, and an electronic device.

[0010]

According to the present invention, there is provided a wiring board in which a plurality of insulating layers and wiring conductors are alternately stacked, and a through hole formed in the insulating layer between upper and lower wiring conductors is filled with a conductor. In the wiring board electrically connected by the through conductors, the wiring conductor is formed of an electroless copper plating layer on the insulating layer and an electrolytic copper plating layer on the electroless copper plating layer or a copper foil on the insulating layer. And the conductor of the through conductor is formed of an electrolytic copper plating layer or electrolytic copper plating formed on a copper foil.

Further, in the wiring board according to the present invention, the thermal expansion coefficient in the thickness direction of the insulating layer is 20 to 60 ppm /
° C.

According to the method of manufacturing a wiring board of the present invention, an electroless copper plating layer and a first wiring conductor formed of an electrolytic copper plating layer or a copper foil on the electroless copper plating layer are formed on the first insulating layer. A step of laminating a second insulating layer on the first insulating layer on which the first wiring conductor is formed, and forming a through hole in the second insulating layer located on the first wiring conductor. Process and
A step of applying an electroless copper plating layer on the second insulating layer and in the through-hole, a step of coating the electroless copper plating layer on the second insulating layer with a plating-resistant resin layer, and The step of removing the exposed electroless copper plating layer, the step of applying a current from the first wiring conductor and filling the through hole with electrolytic copper plating, and after peeling off the plating-resistant resin layer, on the second insulating layer And forming a second wiring conductor by covering the electroless plating layer with an electrolytic copper plating layer.

An electronic device according to the present invention has a mounting electrode for an electronic component electrically connected to a wiring conductor on a surface of the wiring board, and electrically connects an electrode of the electronic component to the mounting electrode. It is characterized by comprising.

According to the wiring board of the present invention, since the conductor of the through conductor is made of the electrolytic copper plating layer or the electrolytic copper plating formed on the copper foil, the connection between the wiring conductor and the through conductor is made. It can be strong. Also, there is no joint between the electroless copper plating and the electrolytic copper plating on the through conductor, and as a result, cracks may occur in the through conductor even if long-term thermal stress is repeatedly applied to the stacked via structure in which the through conductors are vertically arranged. Since no wiring is generated, a wiring board having high connection reliability without disconnection between the through conductor and the wiring conductor can be provided.

Further, according to the wiring board of the present invention, since the thermal expansion coefficient in the thickness direction of the insulating layer is set to 20 to 60 ppm / ° C., the stress due to the difference in thermal expansion generated between the through conductor and the insulating layer. Can be reduced, and a highly reliable wiring board can be obtained in which the through conductor and the insulating layer are not separated from each other in the temperature cycle test and the inside of the through conductor is disconnected.

According to the method of manufacturing a wiring board of the present invention, since the current is supplied from the first wiring conductor and the through hole is filled with electrolytic copper plating, the inner wall of the through hole is not coated with electroless copper plating. Also, the conductor of the through conductor can be favorably formed by electrolytic copper plating. Further, the through holes can be efficiently filled with electrolytic copper plating using a normal electrolytic copper plating apparatus.

According to the electronic device of the present invention, the surface of the wiring board has a mounting electrode of the electronic component electrically connected to the wiring conductor, and the mounting electrode is electrically connected to the electrode of the electronic component. Since they are connected, a small and highly reliable electronic device can be obtained.

[0018]

Next, a wiring board and an electronic device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a wiring board and an electronic device using the same according to the present invention.

In these figures, 1 is an insulating layer, 2 is a wiring conductor, 3 is a through hole, and 4 is a through conductor, and these mainly constitute the wiring board 5 of the present invention. Also, the wiring board 5
The electronic device 7 of the present invention is configured by mounting an electronic component 6 such as a semiconductor element on the electronic device 6.

The wiring board 5 has a function of mounting the electronic components 6, and is formed in a plate-like shape by impregnating a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin into a glass cloth in which glass fibers are woven vertically and horizontally. Core insulating layer 1a
An insulating layer 1 made of a thermosetting resin such as an epoxy resin or a modified polyphenylene ether resin and a wiring conductor 2 made of a copper plating film or a copper foil are alternately laminated on a plurality of layers on the upper and lower surfaces, respectively.

The core insulating layer 1a functions as a support for the insulating layer 1, has a thickness of about 0.3 to 1.5 mm, and has a plurality of through holes 11 with a diameter of about 0.1 to 1.0 mm from the upper surface to the lower surface. are doing. Wiring conductors 2 made of a copper plating film or a copper foil are provided on the upper and lower surfaces thereof through holes 11.
A copper plating film 12 is adhered to the inner wall of the substrate, and the wiring conductors 2 on the upper and lower surfaces are electrically connected through the copper plating film 12 of the through hole 11.

Such a core insulating layer 1a is formed by thermally curing a sheet in which glass cloth is impregnated with an uncured thermosetting resin, and then drilling this from the upper surface to the lower surface to form a through hole 11. Obtained by drilling.

The wiring conductors 2 on the upper and lower surfaces of the core insulating layer 1a have a thickness of 3 to 50 μm on the entire upper and lower surfaces of the sheet for the core insulating layer 1a.
The copper plating film or the copper foil is adhered, and this copper plating film or the copper foil is etched after the sheet is cured to form a predetermined pattern. The copper plating film 12 on the inner wall of the through hole 11 is formed by providing the through hole 11 in the core insulating layer 1a and then depositing a copper plating having a thickness of about 3 to 50 μm on the through hole 11 by a plating method. Is done.

Further, in the core insulating layer 1a, a resin column 13 made of a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin is filled in the through hole 11. The resin pillars 13 are for allowing the insulating layer 2 to be formed directly above and directly below the through holes 11 by closing the through holes 11, and an uncured paste-like thermosetting resin is placed in the through holes 11. It is formed by filling by a screen printing method, heating and curing, and then polishing the upper and lower surfaces thereof to be substantially flat. And this resin pillar
The insulating layer 1 and the wiring conductor 2 are laminated on the upper and lower surfaces of the core insulating layer 1a including 13.

The insulating layer 1 laminated on the upper and lower surfaces of the core insulating layer 1a has a thickness of about 10 to 80 μm, and has a through hole 3 having a diameter of about 20 to 100 μm from the upper surface to the lower surface of each layer. ing. These insulating layers 1 are for providing an insulating interval for wiring the wiring conductors 2 at high density. The upper and lower wiring conductors 2 are electrically connected by a through conductor 4 that fills a through hole 3 formed in the insulating layer 1. Thus, high-density wiring can be formed three-dimensionally.

The insulating layer 1 is made of a thermosetting resin such as an epoxy resin / bismaleimide triazine resin or a modified polyphenylene ether resin, and an inorganic insulating filler such as silica. 60 ppm /
C. is preferred. From the viewpoint of preventing the insulating layer 1 from becoming hard and brittle and causing cracks,
It is preferably at least 20 ppm / ° C., and more preferably at most 60 ppm / ° C. from the viewpoint of preventing disconnection inside the through conductor 4 due to a difference in thermal expansion from the through conductor 4. Insulation layer 1
In order to make the coefficient of thermal expansion 20 to 60 ppm / ° C., an inorganic insulating filler such as silica may be added in an amount of about 50 to 80% by weight based on the thermosetting resin. Such an insulating layer 1 is manufactured by using a mixture of an epoxy resin and silica to which an organic solvent, a plasticizer, and the like are added, for example, by using a well-known doctor blade method.

A wiring conductor 2 is formed on the surface of the insulating layer 1, and a through hole 3 is formed in the insulating layer 1. A through conductor 4 is formed to be electrically connected. The wiring conductor 2 and the through conductor 4 have a function of electrically connecting the mounted electronic component 6 to a wiring conductor (not shown) of an external electric circuit.

The wiring conductor 2 is composed of an electroless copper plating layer and an electrolytic copper plating layer or a copper foil on this electroless copper plating layer, and preferably has a thickness of 3 to 50 μm and transmits a high-speed signal. From the viewpoint of preventing the peeling of the wiring conductor 2 and the insulating layer 1 due to the difference in thermal expansion between the wiring conductor 2 and the insulating layer 1, the thickness is preferably 50 µm or less.

Such a wiring conductor 2 and a through conductor 4
Is formed by the following method when the wiring conductor 2 is composed of, for example, an electroless copper plating layer and an electrolytic copper plating layer. First, an insulating layer 2 is coated on a core insulating layer 1a having a surface on which a wiring conductor 2 is adhered, and a through hole 3 is formed in the insulating layer 2 on the wiring conductor 2 by a laser. Next, the surface of the insulating layer 2 and the inside of the through-hole 3 are immersed in a roughening solution such as an aqueous solution of permanganates to roughen the surface, and thereafter, an electroless film made of copper sulfate, Rossell salt, formalin, sodium EDTA, a stabilizer, etc. By dipping in a copper plating solution for about 30 minutes, electroless copper plating of about 1 to 2 μm is deposited on the surface of the insulating layer 2 and inside the through hole 3. Next, the surface of the insulating layer 2 other than the inside of the through hole 3 is covered with a plating-resistant resin layer, and the through hole 3 is etched.
The inner electroless copper plating is removed, and then the insulating layer 2 is immersed in an electrolytic copper plating solution composed of sulfuric acid / copper sulfate pentahydrate / chlorine / brightener for several hours, and located at the bottom of the through hole 3. Electric current is supplied from the wiring conductor 2 to grow an electrolytic copper plating layer to form a through conductor 4. Then, finally, the plating-resistant resin layer is peeled off with sodium hydroxide, and an electrolytic copper-plated layer is applied on the electroless plating layer on the surface of the insulating layer 2 exposed by peeling off the plating-resistant resin layer. Form 2 Further, by repeating the same steps as described above, the plurality of insulating layers 1 and the wiring conductors 2 are laminated, and the wiring board 5 of the present invention is obtained. In the above-described example, the wiring conductor 2 on the surface of the insulating layer 1 is shown to be composed of an electroless copper plating layer and an electrolytic copper plating layer. However, the wiring conductor 2 may be composed of copper foil. . When the wiring conductor 2 is made of copper foil, a through hole 3 is formed in the insulating layer 1 on the wiring conductor 2 by a laser, and then electricity is applied by using the wiring conductor 2 located at the bottom of the through hole 3. Then, the inside of the through hole 3 may be filled with electrolytic copper plating. In addition, such a copper foil is superposed on the surface of the core insulating layer 1a and the insulating layer 1 in an uncured state, is cured by pressing and heating, and is etched into the shape of the wiring conductor 2. It is formed by this.

According to the wiring board 5 of the present invention, the through conductor 4
Is made of electrolytic copper plating formed on an electrolytic copper plating layer or a copper foil, the connection between the wiring conductor 2 and the through conductor 4 can be made strong.
Further, since there is no joint between the electroless copper plating and the electrolytic copper plating on the through conductor 4, even if a long-term thermal stress is repeatedly applied to the stacked via structure in which the through conductors 4 are vertically arranged, the through conductor 4 Since no cracks occur in the wiring board 5, the wiring board 5 having high connection reliability without disconnection between the through conductor 4 and the wiring conductor 2 can be provided.

Thus, according to the wiring board 5 of the present invention, the conductor of the through conductor 4 is made of electrolytic copper plating;
Since the thermal expansion coefficient in the thickness direction of the insulating layer 1 is 20 to 60 ppm / ° C., even if a long-term thermal stress is repeatedly applied to the stacked via structure in which the penetrating conductors 4 are vertically arranged, cracks are formed in the penetrating conductors 4. A highly reliable wiring board 5 that does not generate or break through the through conductor 4 and the insulating layer 1 and break inside the through conductor 4 can be provided.

It should be noted that the wiring board 5 of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. The layer 1 is laminated on the upper and lower surfaces of the core insulating layer 1a, and the wiring conductor 2 is formed on the insulating layer 1. However, the insulating layer 1 may be laminated on only one of the upper surface and the lower surface of the core insulating layer 1a. Good. Further, in the above-described example, the wiring board 5 is formed by laminating the insulating layer 1 on the core insulating layer 1a. However, the wiring board 5 may be configured only by the insulating layer 1.

Further, the electronic device 7 of the present invention comprises the wiring substrate 5
It is formed by electrically connecting the wiring conductor 2 on the front surface and each electrode of the electronic component 6 via the conductor bump 8. The conductor bumps 8 serve to electrically connect the wiring conductor 2 to each electrode of the electronic component 3, and lead-tin / tin-zinc-tin-silver-bismuth is formed on the wiring conductor 2 on the surface of the wiring board 5. It is formed from a conductive material such as an alloy.

Such a conductive bump 8 is formed by the following method. First, a solder resist layer 9 having an opening exposing a joint between the wiring conductor 2 and the electronic component 6 is applied to the surface of the wiring board 5 by using a conventionally known screen printing method. The solder resist layer 9 has a thickness of 10 to 50 μm.
and an insulating material containing 30 to 70% by weight of an inorganic powder filler such as silica or talc in a mixture of a photosensitive resin such as an acrylic-modified epoxy resin and an initiator. It is possible to prevent electrical shorts between the wiring conductors 2 by the conductor bumps 8 and
Has a function of improving the bonding strength between the insulating layer 1 and the insulating layer 1. Next, when the conductor bump 8 is a solder made of, for example, lead-tin,
A solder paste made of lead-tin is filled by screen printing on the wiring conductor 2 with the opening of the solder resist layer 9 exposed, and is fixed to the wiring conductor 2 in a hemispherical shape by passing through a reflow furnace. If a metal having good conductivity and excellent corrosion resistance, such as nickel or gold, is applied to the surface of the wiring conductor 2 exposed on the surface of the wiring board 5 by plating to a thickness of 1 to 20 μm, the exposed wiring is exposed. Oxidation and corrosion of the conductor 2 can be effectively prevented, and the connection between the wiring conductor 2 and the conductor bump 8 can be made good.

Thereafter, the electrodes of the electronic component 6 are joined to the wiring conductor 2 via the conductor bumps 8 to mount the electronic component 6, and the wiring board 5 and the electronic component 6 are bonded and fixed with an underfill material 10. Further, the electronic component 6 is sealed with a lid or a potting resin (not shown) to form an electronic device 7, and one end of the wiring conductor 2 on the opposite side to the connection portion with the electronic component 6 is connected to the wiring of the external electric circuit board. By connecting to a conductor (not shown), the electronic device 7 of the present invention is mounted on an external electric circuit board.

According to the electronic device 7 of the present invention, the mounting electrode of the electronic component 6 electrically connected to the wiring conductor 2 is provided on the surface of the wiring board 5, and the mounting of the electronic component 6 is performed on the mounting electrode. Since the electrodes are electrically connected, the electronic device 7 can be small and highly reliable.

The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the scope of the present invention.

Next, a method of manufacturing a wiring board according to the present invention will be described with reference to an example in which the above-described wiring board 5 is manufactured.

First, the core insulating layer 1a is prepared. The core insulating layer 1a is formed by drying a sheet obtained by impregnating a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin into a glass cloth in which glass fibers are woven vertically and horizontally, and laminating a plurality of sheets. You.

Next, a copper foil having a thickness of 3 to 50 μm is superimposed on the surface of the core insulating layer 1a and pressurized and heated to form a copper foil serving as the wiring conductor 2 on the surface of the core insulating layer 1a. Then, a through hole 11 is formed by drilling from the upper surface to the lower surface of the core insulating layer 1a having a copper foil serving as the wiring conductor 2 formed on the surface thereof, and then the wiring conductor 2 is formed. A predetermined pattern is formed by etching a copper foil that becomes, and further, on the inner wall of the through hole 11,
By depositing a copper film having a thickness of about 3 to 50 μm using a plating method, a copper plating film 12 is formed on the inner wall of the through hole 11.
To form The through-hole 11 has a resin column 13 made of a thermosetting resin such as an epoxy resin or a bismaleimide triazine resin therein, and an uncured paste-like thermosetting resin in the through-hole 11 formed by screen printing. It is preferable to fill it, and it is preferable to polish the upper and lower surfaces thereof substantially flat after heat curing. Then, the first insulating layer 21A is formed on the core insulating layer 1a.

Next, a method of forming the through conductor 4 and the wiring conductor 2 is shown in FIG. Here, the core insulating layer 1a is omitted. The case where the wiring conductor 2 is composed of an electroless copper plating layer and an electrolytic copper plating layer will be described.

First, as shown in the sectional view of FIG.
Using a well-known subtractive method, the first insulating layer
Electroless copper plating layer 22a and electrolytic copper plating layer 22b on the surface of 21A
Is formed. Next, FIG.
As shown in the cross-sectional view of FIG. 2B, a film of an uncured thermosetting resin having a thickness of about 10 to 80 μm is formed on the first insulating layer 21A on which the first wiring conductor 22 is formed. The second insulating layer 21B is laminated by thermosetting. After a while
As shown in the cross-sectional view of FIG. 2C, the opening diameter of the second insulating layer 21B on the first wiring conductor 22 is 20 to 100 μm by laser.
About m through holes 3 are formed.

Thereafter, as shown in the sectional view of FIG. 2D, the surface of the second insulating layer 21B and the inner wall of the through-hole 3 are immersed in a roughening solution such as an aqueous solution of permanganate at 60 ° C. for 15 minutes. After being converted to an electroless copper plating solution consisting of copper sulfate, Rossell salt, formalin, sodium EDTA, stabilizer, etc.
Then, an electroless copper plating layer 32a having a thickness of about 1 to 2 [mu] m is applied to the surface of the second insulating layer 21B and the inner wall of the through hole 3 by immersion. Further, as shown in the sectional view of FIG. 2E, the electroless copper plating layer 32a on the second insulating layer 21B is covered with a plating-resistant resin layer J. Thereafter, as shown in a sectional view of FIG. 2F, the electroless copper plating layer 32a exposed in the through hole 3 is removed by etching with a copper sulfate solution.

Thereafter, as shown in the sectional view of FIG. 2 (g), the first wiring was immersed for one hour in an electrolytic copper plating solution comprising sulfuric acid, copper sulfate pentahydrate, chlorine, brightener and the like. Conductor 22
And through holes 3 are filled with electrolytic copper plating to form through conductors 4 made of electrolytic copper plating. Further, FIG.
(H) As shown in the cross-sectional view, after the anti-plating resin layer J is peeled off with sodium hydroxide, the electroless copper plating layer 32b is coated on the electroless plating layer 32a on the second insulating layer 21B. The second wiring conductor 32 is formed. And the above (a) ~
By repeating the step (h), a multilayer wiring board can be obtained.

Although FIG. 2 shows that the first insulating layer 21A does not have the through hole 3 and the through conductor 4, the first insulating layer 21A may include the through hole 3 and the through conductor 4 if necessary. May be provided.

According to the method of manufacturing the wiring board 5 of the present invention,
Energize from the first wiring conductor 22 and pass through hole 3 with electrolytic copper plating
Is filled, the conductor of the through conductor 4 can be favorably formed by electrolytic copper plating without applying electroless copper plating to the inner wall of the through hole 3. Further, the through holes can be efficiently filled with electrolytic copper plating using a normal electrolytic copper plating apparatus.

Thus, according to the method of manufacturing the wiring board 5 of the present invention, the electroless copper plating layer 22a is formed on the first insulating layer 21A.
And forming a first wiring conductor 22 made of an electrolytic copper plating layer 22b or copper foil on the electroless copper plating layer 22a,
A step of laminating a second insulating layer 21B on the first insulating layer 21A on which the first wiring conductor 22 is formed, and forming a through hole 3 in the second insulating layer 21B located on the first wiring conductor 22; Forming an electroless copper plating layer 32a on the second insulating layer 21B and in the through hole 3, and forming the electroless copper plating layer 32a on the second insulating layer 21B with a plating resistant resin. A step of coating with the layer J, a step of removing the electroless copper plating layer 32a exposed in the through-hole 3, a step of supplying electricity from the first wiring conductor 22, and filling the through-hole 3 with electrolytic copper plating, After the anti-plating resin layer J is peeled off, the steps of covering the electroless copper plating layer 32b on the electroless plating layer 32a on the second insulating layer 21b and forming the second wiring conductor 32 are sequentially performed. The through hole 3 can be efficiently filled with electrolytic copper plating using a normal electrolytic copper plating apparatus, and the electrolytic copper plating of the wiring conductor 22 can be performed. Since the through conductors 4 filled with electrolytic copper plating can be formed on the metal layer 22a, even if long-term thermal stress is repeatedly applied to the stacked via structure in which the through conductors 4 are vertically arranged, the through conductors 4 do not peel off at the joints. A highly reliable wiring board 5 can be manufactured.

It should be noted that the present invention is not limited to the above-described embodiment, and may be changed or improved without departing from the scope of the present invention.

[0049]

According to the wiring board of the present invention, since the conductor of the through conductor is formed of electrolytic copper plating layer or electrolytic copper plating formed on the copper foil, the conductor of the through conductor and the through conductor are formed. The bonding can be strong. Also,
There is no joint between the electroless copper plating and the electrolytic copper plating on the through conductor, and as a result, cracks do not occur in the through conductor even when long-term thermal stress is repeatedly applied in a stacked via structure in which the through conductor is vertically arranged Therefore, it is possible to provide a wiring board having high connection reliability without disconnection between the through conductor and the wiring conductor.

Further, according to the wiring board of the present invention, since the thermal expansion coefficient in the thickness direction of the insulating layer is set to 20 to 60 ppm / ° C., the stress due to the thermal expansion difference generated between the through conductor and the insulating layer. Can be reduced, and a highly reliable wiring board can be obtained in which the through conductor and the insulating layer are not separated from each other in the temperature cycle test and the inside of the through conductor is disconnected.

According to the method of manufacturing a wiring board of the present invention, since the first wiring conductor is energized to fill the through-hole with electrolytic copper plating, the inner wall of the through-hole does not need to be coated with electroless copper plating. Also, the conductor of the through conductor can be favorably formed by electrolytic copper plating. Further, the through holes can be efficiently filled with electrolytic copper plating using a normal electrolytic copper plating apparatus.

According to the electronic device of the present invention, the surface of the wiring board has electrodes for mounting electronic components electrically connected to the wiring conductors, and the electrodes of the electronic components are electrically connected to the mounting electrodes. Since they are connected, a small and highly reliable electronic device can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of an embodiment in which an electronic component is mounted on a wiring board of the present invention and applied to an electronic device.

FIGS. 2A to 2H are enlarged cross-sectional views of a main part for describing a method of manufacturing a wiring board according to the present invention.

[Description of Signs] 1... Insulating layer 1a... Core insulating layer 2... Wiring conductor 3. 4 through-conductor 5 wiring board 6 electronic component 7 electronic device 21A ... First insulating layer 22B Second insulating layer 22 First wiring conductor 32 .. Second wiring conductors 22a, 32a... Electroless copper plating layers 22b, 32b... Electrolytic copper plating layers J... Plating-resistant resin layers

Claims (4)

[Claims] A plurality of insulating layers and wiring conductors are alternately laminated, and the upper and lower wiring conductors are electrically connected by a through conductor formed by filling a through hole formed in the insulating layer with a conductor. Wherein the wiring conductor comprises an electroless copper plating layer on the insulating layer and an electrolytic copper plating layer on the electroless copper plating layer or a copper foil on the insulating layer, and the through conductor Wherein said conductor is made of electrolytic copper plating formed on said electrolytic copper plating layer or copper foil. 2. The thermal expansion coefficient of the insulating layer in the thickness direction is 2
2. The wiring board according to claim 1, wherein the temperature is 0 to 60 ppm / ° C. Forming a first wiring conductor comprising an electroless copper plating layer on the first insulating layer and an electrolytic copper plating layer or a copper foil on the electroless copper plating layer; Laminating a second insulating layer on the first insulating layer on which the wiring conductor is formed, and forming a through hole in the second insulating layer located on the first wiring conductor, A step of applying an electroless copper plating layer on the second insulating layer and in the through hole, and a step of covering the electroless copper plating layer on the second insulating layer with a plating-resistant resin layer; Removing the electroless copper plating layer exposed in the through-hole, energizing the first wiring conductor to fill the through-hole with electrolytic copper plating, and removing the plating-resistant resin layer. Covering an electroless plating layer on the electroless plating layer on the second insulating layer, And a step of forming a body in order. 4. An electronic component mounting electrode electrically connected to the wiring conductor on a surface of the wiring board according to claim 1 or 2, wherein an electrode of the electronic component is mounted on the mounting electrode. An electronic device characterized by being electrically connected.