JP2003046226A - Wiring board and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board which is high in reliability and kept free from cracks occurring between a resin rod in a through-hole and a surface solder resist layer. SOLUTION: Inner conductors 2A and 2B formed of copper foil are each deposited on the upper and lower surfaces of an insulating resin board 1 for the formation of a double-sided copper-plated board, insulating resin layers 3A and 3B are deposited on the upper and lower surface of the double-sided copper-plated board, through-holes 4 are bored in the double-sided copper-plated board and the insulating resin layers 3A and 3B, penetrating through them in a vertical direction, a through conductor 5 is deposited on the inner walls of the through-holes 4 by plating, surface conductors 6A and 6B are deposited on the surfaces of the insulating resin layers 3A and 3B by plating, the through- holes 4 are each filled up with a resin rod 7, a solder resist layer 8 partially coating the surface conductors 6A and 6B is deposited on the surfaces of the insulating resin layers 3A and 3B for the formation of a wiring board, and the resin rods 7 and the solder resist layer 8 are formed of resin of the same composition in one piece.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic material-based multilayer wiring board.

[0002]

2. Description of the Related Art Conventionally, as a wiring board of an organic material type for mounting a semiconductor element, for example, a double-sided copper clad in which inner layer conductors made of copper foil are adhered on both upper and lower sides of an insulating resin plate made of, for example, a glass-epoxy plate. An insulating resin layer containing an epoxy resin as a main component is applied to both upper and lower surfaces of the plate, and the insulating resin plate and the insulating resin layer have a plurality of through-holes vertically penetrating therethrough, and a through conductor and an inner wall of the through-hole are provided. A multi-layer wiring board is used in which surface conductors are coated on the surface of an insulating resin layer by electroless plating and electrolytic copper plating, respectively. In this wiring board, three-dimensional high-density wiring is possible by electrically connecting the inner-layer conductor and the surface-layer conductor located above and below through the through-conductor attached to the inner wall of the through-hole.

Such an organic material-based multilayer wiring board has a thickness of 7 to 12 .mu.m on both upper and lower sides of an insulating resin plate made of a glass-epoxy plate having a thickness of about 0.35 to 0.45 mm.
An insulating resin layer with a thickness of 25 to 45 μm is applied to both the upper and lower surfaces of a double-sided copper clad board on which an inner layer conductor made of copper foil of about m is adhered, and the diameter is 200 from the upper surface to the lower surface.
Approximately 500 μm through holes are drilled by drilling, then the inner wall of the through holes and the insulating resin layer surface have a thickness of 15
A copper plating layer of about 50 μm is deposited by electroless plating and electrolytic plating, and then an uncured thermosetting resin containing epoxy resin, bismaleimide triazine resin or polyphenylene ether resin as a main component is screened in the through holes. After filling by printing, the resin is thermally cured and the through holes are filled with resin columns made of cured resin, and then the copper plating layer adhered to the surface layer of the insulating resin layer is etched into a predetermined pattern for insulation. A surface layer conductor is formed on the surface of the resin layer, and finally, a photosensitive resin paste made of, for example, an acrylic modified photosensitive epoxy resin or the like is printed and applied by screen printing on the insulating resin layer on which the surface layer conductor is formed. After exposing and developing, heat-curing and photo-curing to form a solder resist layer that covers a part of the surface conductor on the insulating resin layer. Therefore it was produced.

[0004]

However, according to this conventional organic material-based multilayer wiring board, generally, the surfaces of the thermosetting resin and the insulating resin layer that form the resin columns filled in the through holes are formed. Since the coefficient of thermal expansion is different from that of the photosensitive resin that forms the solder resist layer deposited on the substrate, heat is applied, for example, when mounting a semiconductor element on this multilayer wiring board or when the semiconductor element operates. Then, the stress generated by the difference in the thermal expansion coefficient between the resin pillar and the solder resist layer causes cracks to occur at the bond between the resin pillar and the solder resist layer, significantly lowering the long-term reliability of the wiring board. It had a problem that it did.

Further, according to this conventional organic material-based multilayer wiring board, the resin column and the solder resist layer are formed in separate steps, which makes the manufacturing of the wiring board complicated. It had a problem that it would end up.

The present invention has been completed in view of such conventional problems, and an object thereof is to provide a resin column filled in the through hole and a solder resist layer adhered to the surface of the insulating resin layer. An object of the present invention is to provide an organic material-based multilayer wiring board having high long-term reliability in which cracks do not occur.
Furthermore, another object of the present invention is to simplify the manufacture of a multilayer wiring board.

[0007]

According to the present invention, an insulating resin layer is applied to both upper and lower surfaces of a double-sided copper-clad board in which inner layer conductors made of copper foil are applied to upper and lower surfaces of an insulating resin plate.
A plurality of through-holes are formed vertically through the double-sided copper clad board and the insulating resin layer, and a through conductor is formed on the inner wall of the through hole and a surface layer conductor is formed by plating on the surface of the insulating resin layer. In the wiring board in which the through holes are filled with resin pillars and the surface of the insulating resin layer is covered with a solder resist layer that covers a part of the surface conductor, the resin pillars and the solder resist layer have the same composition. It is characterized by being integrally formed of the resin.

Further, according to the manufacturing method of the present invention, an insulating resin layer is adhered on both upper and lower sides of a double-sided copper clad plate in which inner layer conductors made of copper foil are adhered on the upper and lower sides of the insulating resin plate, respectively, and these double-sided copper layers are coated. Form a plurality of through-holes that vertically penetrate the tension plate and the insulating resin layer, then deposit the through-conductor and the surface-layer conductor on the surface of the insulating resin layer by plating on the inner wall of the through-hole, and then in the through-hole. And the insulating resin layer surface is filled and applied with an uncured resin of the same composition, respectively, and then the resin is cured so that the resin column is cured in the through hole and the resin is cured on the surface of the insulating resin layer. The resist layer is integrally formed.

According to the multilayer wiring board of the present invention, the resin column filled in the through hole and the solder resist layer deposited on the surface of the insulating resin layer are integrally formed of the resin having the same composition. The cracks caused by the difference in thermal expansion coefficient between the resin column and the solder resist layer do not occur.

Further, according to the method of manufacturing a multilayer wiring board of the present invention, since the resin pillar in the through hole and the surface solder resist layer are integrally formed of the resin having the same composition, the resin pillar and the solder resist layer are formed. It is possible to provide a highly reliable wiring board in which no crack is generated between the wiring boards by an extremely simple method.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a method for manufacturing a wiring board according to the present invention will be described in detail. FIG. 1 is a partial cross-sectional view showing an example of an embodiment of a wiring board manufactured by the manufacturing method of the present invention. In FIG. 1, 1 is an insulating resin plate, 2A
2B is an inner layer conductor, 3A and 3B are insulating resin layers, 4 is a through hole, 5 is a through conductor, 6A and 6B are surface layer conductors, 7 is a resin column, and 8 is a solder resist layer, which are above and below the insulating resin plate 1. Inner layer conductors 2A and 2B and insulating resin layers 3A and 3 on both sides
B is deposited and the insulating resin plate 1 and the inner layer conductor 2
A.2B and insulating resin layers 3A and 3B are penetrated by a plurality of through holes 4, a through conductor 5 is adhered to the inner wall of the through hole 4, and a surface conductor is formed on the surface of the insulating resin layers 3A and 3B. 6A and 6B are adhered and formed, the resin column 7 is filled in the through hole 4, and the insulating resin layers 3A and 3B are formed.
The wiring board of the present invention is configured by providing the solder resist layer 8 on B.

The insulating resin plate 1 functions as a core member of a wiring board, and is made of, for example, an organic insulating material obtained by impregnating glass cloth or aramid cloth with a resin such as epoxy resin or bismaleimide triazine resin / polyphenylene ether resin. Is a flat plate with a thickness of 0.35 to 0.45 mm, and an inner layer conductor 2A consisting of copper foil with a thickness of 7 to 12 μm on both upper and lower surfaces.
2B is adhered to form a so-called double-sided copper-clad plate. If the thickness of the insulating resin plate 1 is less than 0.35 mm, the insulating resin layers 3A and 3B are attached to the upper and lower surfaces thereof, or the insulating resin plate 1 and the inner layer conductors 2A and 2B and the insulating resin layers 3A and 3B are penetrated. When forming a plurality of through-holes 4, there is a great risk that the wiring board will be warped or deformed due to the influence of heat or external force, and the flatness required for the wiring board cannot be secured. And, on the other hand, 0.45
If it exceeds mm, when the through conductor 5 is formed on the inner wall of the through hole 4 as described later, it is difficult for the plating solution to penetrate into the through hole 4, and it is difficult to form the through conductor 5 well. Therefore, the thickness of the insulating resin plate 1 is 0.35 to 0.45 mm
Is preferred.

The insulating resin plate 1 is made of a resin such as epoxy resin or bismaleimide triazine resin / polyphenylene ether resin impregnated in glass cloth or aramid cloth, and a filler made of silica, alumina or aramid resin in glass cloth or aramid resin. If the fiber portion such as the cloth and the resin portion are contained so that the laser light transmittance is substantially equal to each other, when the through holes 4 are formed in the insulating resin plate 1 by the laser light, as will be described later, the through holes 4 are penetrated. The holes 4 can be favorably formed in the insulating resin plate 1 with a substantially uniform size. Therefore, in the resin such as epoxy resin, bismaleimide triazine resin, polyphenylene ether resin, etc., which is impregnated in the glass cloth or aramid cloth of the insulating resin plate 1, a filler made of silica, alumina, aramid resin or the like is added to the resin such as glass cloth or aramid cloth. It is preferable that the fiber portion and the resin portion are contained so that the laser beam transmittances thereof are substantially equal to each other.

The inner layer conductors 2A and 2B attached to the upper and lower surfaces of the insulating resin plate 1 are made of copper foil and mainly serve as a power source layer and a ground layer, and an inner layer wiring conductor pattern W and the inner layer wiring conductor pattern W. To a dummy conductor pattern D electrically independent of each other, the thickness thereof is 7 to 12 μm, and the center line average roughness Ra of the surface thereof is about 0.2 to 2 μm. When the thickness of the inner layer conductors 2A and 2B is less than 7 μm, sufficient electrical characteristics cannot be imparted to the inner layer wiring conductor pattern W as a power supply layer or a ground layer. Insulating resin plate 1
When the through hole 4 penetrating the inner layer conductors 2A and 2B and the insulating resin layers 3A and 3B is formed by laser processing,
It becomes difficult to stably form the through hole 4. Therefore, the thickness of the inner layer conductors 2A and 2B is preferably in the range of 7 to 12 μm.

The inner layer conductors 2A and 2B are provided with inner layer wiring conductor patterns W or dummy conductor patterns D, which penetrate through the through holes 4 and contact the through conductors 5 which will be described later, corresponding to all the through holes 4. Once formed,
When the through holes 4 are drilled by laser processing, all the through holes 4 can be formed to have a substantially uniform size and shape by making the absorption and reflection of the laser light substantially the same in all the through holes 4. Therefore, the inner layer conductors 2A and 2B are preferably formed so as to have the inner layer wiring conductor pattern W or the dummy conductor pattern D which is penetrated by the through holes 4 corresponding to all the through holes 4. In this case, the diameter of the dummy conductor pattern D is 40 to 100 times larger than the diameter of the through hole 4.
The pattern may be a substantially circular pattern having a large size of about μm, and a space having a width of about 30 to 60 μm may be provided between the pattern and the inner layer wiring conductor pattern W. The diameter of the dummy conductor pattern D is the through hole 4
If the diameter is larger than 40 μm by less than 40 μm, it becomes difficult to accurately penetrate the dummy conductor pattern D when the through hole 4 is formed by laser processing. On the other hand, if it is larger than 100 μm, the inner layer wiring conductor is formed. It becomes difficult to take a large area of the pattern W. In addition, the dummy conductor pattern D
When the distance between the inner layer wiring conductor pattern W and the inner layer wiring conductor pattern W is less than 30 μm, the dummy conductor pattern D and the inner layer wiring conductor pattern W
Tends to lose good electrical insulation between the
On the other hand, when it exceeds 60 μm, it becomes difficult to take a large area of the inner layer wiring conductor pattern W.

The inner layer conductors 2A and 2B have a center line average roughness Ra of less than 0.2 μm.
A.2B and the insulating resin layers 3A and 3B do not firmly adhere to each other, and peeling tends to occur between the inner layer conductors 2A and 2B and the insulating resin layers 3A and 3B. On the other hand, when the thickness exceeds 2 μm, It tends to be difficult to form such a rough surface stably and efficiently. Therefore, the inner layer conductor 2A
The center line average roughness Ra of the 2B surface is preferably in the range of 0.2 to 2 μm.

The insulating resin layers 3A and 3B attached to the upper and lower surfaces of the insulating resin plate 1 are made of a thermosetting resin such as epoxy resin, bismaleimide triazine resin, polyphenylene ether resin, etc., and have a degree of decomposition with respect to laser light. It is larger than the insulating resin plate 1 and has surface conductors 6A and 6B on its surface.
Is being worn. The insulating resin layers 3A and 3B are provided to provide an insulating space for electrically insulating the inner layer conductors 2A and 2B and the surface layer conductors 6A and 6B that are to be insulated from each other, and the thickness thereof is the inner layer conductor 2A. 25-45 μm on 2B
Is. When the insulating resin layers 3A and 3B have a thickness of less than 25 μm on the inner layer conductors 2A and 2B, they can electrically insulate the inner layer conductors 2A and 2B and the surface layer conductors 6A and 6B that should be insulated from each other. On the other hand, if it exceeds 45 μm, on the other hand, when the through holes 4 penetrating the insulating resin plate 1, the inner layer conductors 2A and 2B, and the insulating resin layers 3A and 3B are drilled by laser processing, the through holes 4 should be well formed. Will be difficult. Therefore, the thickness of the insulating resin layers 3A and 3B is preferably 25 to 45 μm on the inner layer conductors 2A and 2B.

The surface layer conductors 6A and 6B formed on the surfaces of the insulating resin layers 3A and 3B are made of a copper plating film having a thickness of 8 to 30 μm, and form a surface layer wiring pattern including power supply wiring, ground wiring and signal wiring. is doing. And
For example, an electrode of an electronic component (not shown) is connected to an exposed part of the surface layer conductor 6A on the upper surface side via solder, and
An exposed part of the surface layer conductor 6B on the lower surface side is connected to another wiring board (not shown) or the like via solder.

When the surface layer conductors 6A and 6B have a thickness of less than 8 μm, the surface layer wiring pattern has a high electric resistance. On the other hand, when the thickness exceeds 30 μm, the surface layer wiring pattern can be formed at a high density. It will be difficult. Therefore, the thickness of the surface layer conductors 6A and 6B is preferably in the range of 8 to 30 μm.

The insulating resin plate 1 and the inner layer conductor 2A
A through hole 4 is formed by laser processing so as to penetrate through 2B and the insulating resin layers 3A and 3B, and a through conductor 5 is adhered to the inner wall of the through hole 4. The through hole 4 is for providing a lead-out path for leading out the through conductor 5 from the upper surface of the insulating resin layer 3A to the lower surface of the insulating resin layer 3B. The through hole 4 has a diameter of 75 to 11 in the insulating resin plate 1 because it is formed by laser processing.
Insulating resin layer 3A ・ 3
In B, the inner wall has a shape inclining at an angle of 10 to 30 degrees from the vertical direction and expanding toward the outside. In this case, since the insulating resin layers 3A and 3B have a greater degree of decomposition with respect to the laser light than the insulating resin plate 1, the insulating resin layers 3A and 3B are decomposed more than the insulating substrate 1 during laser processing. In the layers 3A and 3B, the diameter is expanded outward.

Thus, the diameter of the through hole 4 is as small as 75 to 115 μm in the insulating resin plate 1 and the inner wall of the insulating resin layer 3A, 3B is directed outward at an angle of 10 to 30 degrees from the vertical direction. By forming the expanding shape, the through conductors 5 and the surface layer conductors 6A and 6B can be arranged at a high density, whereby a wiring board having extremely high-density wiring can be obtained.

The diameter of the through hole 4 is different from that of the insulating resin plate 1.
, The inner wall is substantially vertical in the insulating resin plate 1 and the insulating resin layers 3A and 3B are small.
Has a shape that expands outward at an angle of 10 to 30 degrees from the vertical direction. Therefore, when the through conductor 5 is attached to the inner wall of the through hole 4 as described later, the through conductor 5
The plating solution for forming the satisfactorily enters the inside of the through-hole 4, and as a result, the through-conductor 5 can be satisfactorily formed in the through-hole 4, and as will be described later, the through-hole 4
When forming the resin pillars 7 therein, the resin paste for forming the resin pillars 7 satisfactorily enters the through holes 4, and as a result, the resin pillars 7 can be formed well in the through holes 4. .

When the diameter of the through hole 4 in the insulating resin plate 1 is less than 75 μm, when the through conductor 5 is formed on the inner wall of the through hole 4, a plating solution for forming the through conductor 5 is used. It is difficult to satisfactorily form the through conductor 5 on the inner wall of the through hole 4 without entering the inside of the through hole 4 well.
If it exceeds 115 μm, the through conductor 5 and the surface layer conductor 6A
It becomes difficult to arrange 6B at a high density. Therefore, the diameter of the through hole 4 in the insulating resin plate 1 is 75 to 115.
The range of μm is preferred.

If the inner wall of the through hole 4 in the insulating resin plate 1 is not substantially vertical, air bubbles are likely to be left inside the through hole 4 when the through conductor 5 is adhered to the inner wall of the through hole 4, and therefore the through hole 4 is not penetrated. The plating solution for forming the conductor 5 does not reach the portion where the bubbles are left unsatisfactorily, and it becomes difficult to form the through conductor 5 on the inner wall of the through hole 4 well. Therefore, the inner wall of the through hole 4 in the insulating resin plate 1 is preferably substantially vertical.

Further, the inner wall of the through hole 4 has an insulating resin layer 3A.
In 3B, the angle that spreads outward is 10 from the vertical direction.
In the case of less than 10 degrees, when the through conductor 5 is formed on the inner wall of the through hole 4 by plating, the plating solution for forming the through conductor 5 does not well enter into the through hole 4 and the through conductor is formed on the inner wall of the through hole 4. 5 becomes difficult to form well, and when the resin pillar 7 is formed in the through hole 4, the resin paste for forming the resin pillar 7 does not well enter the inside of the through hole 4 and It tends to be difficult to form the pillar 7 satisfactorily. On the other hand, when it exceeds 30 degrees, it becomes difficult to stably and efficiently form the through hole 4 in which the inner wall expands at such an angle. Therefore, the inner wall of the through hole 4 has the insulating resin layer 3A.
The angle that spreads outward in 3B is from the vertical direction.
The range of 10 to 30 degrees is preferable.

The through conductor 5 adhered to the inner wall of the through hole 4 is made of a copper plating film having a thickness of about 8 to 25 μm, and is located above and below the insulating resin plate 1 and the insulating resin layers 3A and 3B. Inner layer conductors 2A and 2B and surface layer conductors 6A and 6B
It functions as a connecting conductor that electrically connects the two to each other.

When the thickness of the through conductor 5 is less than 8 μm, the electrical resistance of the through conductor 5 tends to be too high. On the other hand, when the thickness exceeds 25 μm, the through hole 4 to which the through conductor 5 is attached is formed. It becomes difficult to favorably form the resin column 7 inside. Therefore, the thickness of the through conductor 5 is 8
It is preferably in the range of -25 μm.

Further, in the wiring board of the present invention, the through holes 4 are filled with resin pillars 7 formed by curing, for example, acrylic modified photosensitive epoxy resin, and the insulating resin layers 3A and 3B are formed. A solder resist layer 8 formed by curing a photosensitive epoxy resin which is also acrylic-modified is applied on the surface in a predetermined pattern exposing a part of the surface layer conductors 6A and 6B.

The resin pillar 7 and the solder resist layer 8 are
The through conductor 5 and the surface layer conductors 6A and 6B function as a protective layer for protecting the surface layer wiring patterns of the surface layer conductors 6A and 6B from each other, while protecting them from the external environment. It is integrally formed.

As described above, since the resin pillar 7 and the solder resist layer 8 are integrally formed of the resin having the same composition, there is no joint between the resin pillar 7 and the solder resist layer 8 and the thermal expansion of both is performed. Since the coefficients are the same,
Even when heat is applied when the semiconductor element is mounted on the wiring board or when the semiconductor element operates, cracks do not occur between the resin column 7 and the solder resist layer 8.
Therefore, according to the wiring board of the present invention, it is possible to provide a wiring board having extremely high reliability.

If the thickness of the surface solder resist layer 8 on the surface conductors 6A and 6B is less than 10 μm, the surface conductor 6 cannot be well protected and the surface wirings of the surface conductors 6A and 6B are not protected. It tends to be difficult to electrically insulate the patterns from each other, and when it exceeds 40 μm, it tends to be difficult to form the solder resist layer 8 in a predetermined pattern. Therefore, the surface conductor 6 of the solder resist layer 8
The thickness on A · 6B is preferably in the range of 10 to 40 μm.

Next, a method for manufacturing the wiring board shown in FIG. 1 by the manufacturing method of the present invention will be described with reference to FIGS.
Will be described with reference to.

First, as shown in the partial cross-sectional view of FIG. 2A, for example, an organic insulating material obtained by impregnating glass cloth or aramid cloth with a resin such as an epoxy resin, a bismaleimide triazine resin, or a polyphenylene ether resin is used. A double-sided copper clad plate is prepared in which inner layer conductors 2A and 2B made of copper foil having a thickness of 7 to 12 μm are adhered to the upper and lower surfaces of the insulating resin plate 1 having a thickness of 0.35 to 0.45 mm. The inner layer conductor 2A
・ 2B has a center line average roughness Ra of its surface of 0.2 to 2 μm.
The surface is roughened to a certain degree.

If the thickness of the insulating resin plate 1 is less than 0.35 mm, the insulating resin layers 3A and 3B are adhered to the upper and lower surfaces of the insulating resin plate 1, or the insulating resin plate 1 and the inner conductors 2A and 2B and the insulating resin layers 3A and 3B. There is a high risk that the wiring board may be warped or deformed due to the influence of heat, external force, or the like when the plurality of through holes 4 are penetrated through the wiring board 4 and the flatness required for the wiring board cannot be secured. And, on the other hand, 0.45
When it exceeds mm, when the through conductor 5 is formed on the inner wall of the through hole 4 as described later, it is difficult for the plating solution to enter the through hole 4, and the through conductor 5 is likely to be broken. Therefore, the thickness of the insulating resin plate 1 is preferably 0.35 to 0.45 mm.

When the thickness of the inner layer conductors 2A and 2B is less than 7 μm, the pattern of the inner layer conductors 2A and 2B cannot be provided with sufficient electric characteristics as a power source layer or a ground layer. In the case of exceeding, the through hole 4 is stably formed when the through hole 4 penetrating the insulating resin plate 1, the inner layer conductors 2A and 2B and the insulating resin layers 3A and 3B is formed by laser processing as described later. Becomes difficult. Therefore, the thickness of the inner layer conductors 2A and 2B is
The range of 7 to 12 μm is preferable.

When the center line average roughness Ra of the surface of the inner layer conductors 2A and 2B is less than 0.2 μm, the insulating resin layers 3A and 3B are attached to the upper and lower surfaces of the insulating resin plate 1 as described later. The inner layer conductors 2A and 2B and the insulating resin layer 3A
3B does not firmly adhere to each other and peeling tends to occur between the inner layer conductors 2A and 2B and the insulating resin layers 3A and 3B. On the other hand, when it exceeds 2 μm, such a rough surface is stably and efficiently formed. It tends to be difficult to form well. Therefore, the center line average roughness R of the inner layer conductors 2A and 2B
The range of a is preferably 0.2 to 2 μm.

Further, in the inner layer conductors 2A and 2B, if a pattern to be penetrated by the through holes 4 is provided at the position where the through holes 4 are formed corresponding to all the through holes 4, the through holes 4 are formed by laser processing. At the time of formation, the absorption and reflection of the laser light is uniform in all the through holes 4, and all the through holes 4 can be formed substantially uniformly. Therefore, it is preferable that the inner-layer conductors 2A and 2B be provided with patterns corresponding to all the through holes 4 at positions where the through holes 4 are formed.

In such inner layer conductors 2A and 2B, a copper foil having a thickness of about 8 to 16 μm is adhered on the entire upper and lower surfaces of the insulating resin plate 1, and a photosensitive dry film resist is applied on the copper foil. Then, this photosensitive dry film resist is exposed and developed by a conventionally known photolithography technique to form an etching mask having the dry film resist at a pattern forming position, and then the copper foil exposed from the etching mask is chlorinated. 2 Etch away using an etching solution consisting of an aqueous solution of copper or ferric chloride, and finally remove the etching mask, and then etch the surface with a roughening solution containing formic acid in an aqueous solution of cupric chloride. It is formed by roughening.

Next, as shown in the partial cross-sectional view of FIG. 2B, the inner layer conductors 2A.
Insulating resin layers 3A and 3B having a thickness of 25 to 45 .mu.m are deposited on B. The insulating resin layers 3A and 3B are made of a thermosetting resin such as an epoxy resin, a bismaleimide triazine resin, or a polyphenylene ether resin, and have a higher degree of decomposition than a laser beam such as a carbon dioxide gas laser than the insulating resin plate 1.

When the thickness of the insulating resin layers 3A and 3B is less than 25 μm on the inner layer conductors 2A and 2B, the inner layer conductors 2A and 2B and the surface layer conductors 6A and 6B which should be insulated from each other are electrically well insulated. Can not be, on the other hand, 45μ
If it exceeds m, insulating resin plate 1 and inner layer conductors 2A and 2B
In addition, it becomes difficult to satisfactorily form the through holes 4 when the through holes 4 penetrating the insulating resin layers 3A and 3B are formed by laser processing. Therefore, the thickness of the insulating layers 3A and 3B is preferably in the range of 25 to 45 μm on the inner layer conductors 2A and 2B.

The inner conductor 2 is formed on the upper and lower surfaces of the insulating resin plate 1.
To form the insulating resin layers 3A and 3B on the upper and lower surfaces of the double-sided copper-clad board formed by depositing A and 2B, a semi-cured thermosetting resin film is formed on both upper and lower surfaces of the double-sided copper-clad board. A method is employed in which after temporary pressure bonding with a vacuum laminator, this is heat treated to cure.

Next, as shown in the partial sectional view of FIG. 2 (c), a plurality of through holes 4 penetrating the insulating resin layers 3A and 3B, the inner layer conductors 2A and 2B and the insulating resin plate 1 are formed by laser processing. . The through hole 4 has a diameter of 75 to 115 μm in the insulating resin plate 1 and its inner wall is substantially vertical. In the insulating resin layers 3A and 3B, the inner wall is 10 to 10 μm from the vertical direction.
The shape should be expanded outward at an angle of 30 degrees. In this case, the degree of decomposition of the insulating resin layers 3A and 3B with respect to the laser light is set to be larger than that of the insulating resin plate 1, so that the inner wall of the through hole 4 is substantially perpendicular to the insulating resin plate 1 and the insulating resin layers 3A and 3B. In, the shape can be expanded outward at an angle of 10 to 30 degrees from the vertical direction.

As described above, the diameter of the through hole 4 is as small as 75 to 115 μm in the insulating resin plate 1, and the inner wall of the through hole 4 is formed in the insulating resin layers 3A and 3B at an angle of 10 to 30 degrees from the vertical direction. If the shape is expanded outward, as will be described later, the through conductor 5 and the surface conductors 6A and 6A
When forming B, the through conductor 5 and the surface layer conductors 6A and 6B
Can be arranged at a high density, whereby a high-density wiring board can be obtained.

The diameter of the through hole 4 is the insulating resin plate 1
, The inner wall is substantially vertical in the insulating resin plate 1 and the insulating resin layers 3A and 3B are small.
Has a shape that expands outward at an angle of 10 to 30 degrees from the vertical direction. Therefore, when the through conductor 5 is attached to the inner wall of the through hole 4 as described later, the through conductor 5
The plating solution for forming the satisfactorily enters the inside of the through-hole 4, and as a result, the through-conductor 5 can be satisfactorily formed in the through-hole 4, and as will be described later, the through-hole 4
When the resin pillar 7 is formed in the resin pillar 7, the resin paste for forming the resin pillar 7 can enter the inside of the through hole 4 well, and as a result, the resin pillar 7 can be well formed in the through hole 4. it can.

When the diameter of the through hole 4 in the insulating resin plate 1 is less than 75 μm, when the through conductor 5 is formed on the inner wall of the through hole 4, a plating solution for forming the through conductor 5 is used. 4, it is difficult to form the through conductor 5 in the inner wall of the through hole 4 satisfactorily.
If it exceeds 115 μm, the through conductor 5 and the surface layer conductor 6A
It becomes difficult to arrange 6B at a high density. Therefore, the diameter of the through hole 4 in the insulating resin plate 1 is 75 to 115.
The range of μm is preferred.

Further, when the inner wall of the through hole 4 in the insulating resin plate 1 is not substantially vertical, air bubbles are likely to be left inside the through hole 4 when the through conductor 5 is formed on the inner wall of the through hole 4, and therefore the through hole 4 is not penetrated. The plating solution for forming the conductor 5 does not reach the portion where the bubbles are left unsatisfactorily, and it becomes difficult to form the through conductor 5 on the inner wall of the through hole 4 well. Therefore, the inner wall of the through hole 4 in the insulating resin plate 1 is preferably substantially vertical.

Further, the inner wall of the through hole 4 has an insulating resin layer 3A.
In 3B, the angle that spreads outward is 10 from the vertical direction.
In the case of less than 10 degrees, when the through conductor 5 is formed on the inner wall of the through hole 4 by plating, the plating solution for forming the through conductor 5 does not well enter into the through hole 4 and the through conductor is formed on the inner wall of the through hole 4. 5 becomes difficult to form well, and when the resin pillar 7 is formed in the through hole 4, the resin paste for forming the resin pillar 7 does not enter the inside of the through hole 4 well and penetrates the through hole 4. It tends to be difficult to satisfactorily form the resin column 7 in the hole 4, while if it exceeds 30 degrees, it is difficult to stably and efficiently form the through hole 4 in which the inner wall expands at such an angle. Becomes Therefore, the angle at which the inner wall of the through hole 4 expands outward in the insulating resin layers 3A and 3B is preferably in the range of 10 to 30 degrees from the vertical direction.

In order to form the through holes 4 in the insulating resin layers 3A and 3B, the inner layer conductors 2A and 2B and the insulating resin plate 1, for example, the energy of laser light is favorably absorbed on the insulating resin layers 3A and 3B. A laser processing sheet made of a resin having a black color or a color close to black is attached, and a carbon dioxide laser beam with an output of 7 to 12 mJ is applied at a predetermined position with a pulse width of 50 to 500 μs from above the laser processing sheet. The method of irradiating the through holes to form the through holes 4 is adopted. At this time, if the output of carbon dioxide laser light is less than 7 mJ, it tends to be difficult to perforate the through-hole 4 to a sufficient size, while if it exceeds 12 mJ, the insulating resin layers 3A and 3B are formed.
There is a tendency that the hole diameter of the through hole 4 in the above becomes too large. Therefore, the carbon dioxide laser light to be applied is
It is preferable that the output is 7 to 12 mJ and the pulse width is in the range of 50 to 500 μsec. The laser processing sheet is peeled off after the through holes 4 are punched. By forming the through holes 4 by laser processing in this manner, the insulating resin plate 1 has a diameter of 75 to 115 μm and its inner wall is substantially vertical, and the insulating resin layers 3A and 3B have their inner walls extending from the vertical direction 10 It is possible to easily form the through hole 4 having a shape in which the diameter is expanded outward at an angle of -30 degrees.

Next, as shown in the partial cross-sectional view of FIG. 2D, a plating film made of an electroless copper plating film having a thickness of 1 to 3 μm is formed on the inner wall of the through hole 4 and the surfaces of the insulating resin layers 3A and 3B.
Apply 13A. In order to deposit the plating film 13A made of an electroless copper plating film, for example, a palladium activating solution containing ammonium chloride palladium acetate is used to form palladium on the inner walls of the through holes 4 and the surfaces of the insulating resin layers 3A and 3B. The catalyst may be attached, and an electroless copper plating film may be deposited on the catalyst using a copper sulfate-based electroless copper plating solution. At this time, the through hole 4 is formed by the insulating resin layer 3A.
Since the diameter is expanded outward in 3B, the electroless copper plating solution satisfactorily penetrates into the through hole 4, and as a result,
The electroless copper-plated film can be satisfactorily adhered to the inner wall of the through hole 4 and the surfaces of the insulating resin layers 3A and 3B in a substantially uniform thickness. The plating film 13A made of electroless copper plating film
Before depositing, the center line average roughness Ra of the insulating resin layers 3A and 3B and the inner wall of the through hole 4 is 0.2 to 2 μm by using a roughening liquid composed of, for example, potassium permanganate solution or sodium permanganate solution. By roughening to a certain degree, the plating film 13A made of an electroless copper plating film can be firmly adhered. Therefore, before applying the plating film 13A made of the electroless copper plating film, the insulating resin layer 3
The surfaces of A and 3B and the inner walls of the through holes 4 are roughened by using a roughening solution composed of, for example, a potassium permanganate solution or a sodium permanganate solution so that the center line average roughness Ra is about 0.2 to 2 μm. It is preferable.

Next, as shown in the partial sectional view of FIG. 2 (e), a plating mask 14 is deposited on the electroless copper plating film on the insulating layers 3A and 3B and exposed from the plating mask 14. An electrolytic copper-plated film having a thickness of about 10 to 35 μm was deposited on the electroless copper-plated film, and the inner wall of the through-hole 4 and the pattern formation site on the surfaces of the insulating resin layers 3A and 3B were selectively thickly deposited. A plating film 13B including an electroless plating film and an electrolytic copper plating film is formed.

For the plating mask 14, for example, a photosensitive dry film resist is deposited on the electroless copper plating film on the insulating resin layers 3A and 3B, and this dry film resist is exposed and developed by a photolithography technique. Then, it is formed by processing into a predetermined pattern.

As the electrolytic copper plating solution for depositing the electrolytic copper plating film, for example, an electrolytic copper plating solution composed of copper sulfate can be used. At this time, the through hole 4 is
Since the diameters of the insulating resin layers 3A and 3B are expanded outward, the electrolytic copper plating solution satisfactorily penetrates into the through holes 4, resulting in the inner walls of the through holes 4 and the insulating resin layers 3A and 3B.
An electrolytic copper plating film is satisfactorily deposited on the surface of B in a substantially uniform thickness.

Next, as shown in the partial sectional view of FIG. 2 (f), the plating mask 14 is removed and the plating mask 14 is removed.
The electroless copper-plated film and the electrolytic copper-plated film are etched until the electroless copper-plated film underneath disappears to form the through conductor 5 on the inner wall of the through hole 4 and the insulating resin layer 3A.
Form surface conductors 6A and 6B on the surface of 3B.

To etch the electroless copper-plated film and the electrolytic copper-plated film, an etching solution containing a cupric chloride aqueous solution or a ferric chloride aqueous solution may be used.

Next, as shown in the partial cross-sectional view of FIG. 2G, the inside of the through hole 4 and the entire surface of the insulating resin layers 3A and 3B are made of, for example, a photosensitive epoxy resin modified with acrylic. Fill and apply the photosensitive resin paste 15.

Inside the through hole 4 and the insulating resin layers 3A, 3A
In order to fill and apply the photosensitive resin paste 15 made of, for example, an acrylic modified photosensitive epoxy resin on the entire surface of B, the photosensitive resin paste 15 adjusted to a predetermined viscosity is adopted by the screen printing method. For example, a method of printing the entire surface twice from the insulating layer 3A side and the insulating layer 3B side is adopted. By printing twice each time in this manner, the photosensitive resin paste 15 can be extremely well filled in the through holes 4, and the photosensitive resin paste 15 is applied to the surfaces of the insulating layers 3A and 3B with a uniform thickness. can do.

In this case, it is desirable that the photosensitive resin paste 15 used for the first printing has a viscosity of 150 to 280 dPa · s. If the viscosity is lower or higher than this range, it becomes difficult to satisfactorily fill the through hole 4 with the photosensitive resin paste 15, and there is a risk that air bubbles may be caught in the filled photosensitive resin paste 15. It gets bigger. The viscosity of the photosensitive resin paste 15 used for the second printing is, for example, 50 to 50 depending on the thickness to be printed.
It is only necessary to adopt a material of about 500 dPa · s.

At this time, the through holes 4 are formed in the insulating resin layer 3
Since the diameters of A and 3B are expanded toward the outside, the photosensitive resin paste 15 that becomes the resin pillars 7 is satisfactorily infiltrated into the through holes 4, and as a result, the photosensitive pillars 7 that become the resin pillars 7 are formed inside the through holes 4. The resinous resin paste 15 can be filled well.

Finally, as shown in the partial sectional view of FIG. 2 (h), the photosensitive resin paste 15 filled and applied in the through holes 4 and on the surfaces of the insulating resin layers 3A and 3B is exposed in a predetermined pattern. After that, the wiring board of the present invention as shown in FIG. 1 is completed by developing and curing.

As described above, according to the method for manufacturing a wiring board of the present invention, the resin pillar 7 and the solder resist layer 8 are integrally formed of the resin having the same composition at the same time. It is possible to provide a highly reliable wiring board in which no crack is generated between the wiring boards by an extremely simple method.

[0061]

As described above, according to the wiring board of the present invention, the resin column filled in the through hole and the solder resist layer adhered to the surface of the insulating resin layer are made of the resin having the same composition. Since the resin pillar and the solder resist layer are integrally formed, no crack is generated due to the difference in thermal expansion coefficient between the resin pillar and the solder resist layer. Therefore, it is possible to provide a high-density multilayer wiring board having excellent reliability.

Further, according to the manufacturing method of the present invention, since the resin pillar in the through hole and the surface solder resist are integrally formed of the resin having the same composition, a crack is generated between the resin pillar and the solder resist layer. It is possible to provide a highly reliable wiring board that does not require a very simple method.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an example of an embodiment of a wiring board manufactured by a manufacturing method of the present invention.

2A to 2H are partial cross-sectional views of respective steps for explaining the method for manufacturing a wiring board of the present invention.

[Explanation of symbols]

1 ... Insulating resin plate 2A ・ 2B ・ ・ ・ Inner conductor 3A / 3B ... Insulating resin layer 4 ... through-hole 5 ・ ・ ・ ・ Penetrating conductor 6A, 6B ... Surface conductor 7 ... Resin columns 8 ...- Solder resist layer

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5E314 AA25 BB06 BB11 BB12 CC01                       FF05 GG09                 5E317 AA24 BB02 BB12 CC31 CD17                       CD23 CD27 GG05 GG09                 5E346 AA06 AA12 AA15 AA17 AA32                       AA42 BB01 CC02 CC08 CC31                       CC46 DD01 DD22 EE31 FF04                       GG01 GG15 GG17 HH11 HH18

Claims (2)

[Claims] 1. A double-sided copper clad plate having inner and outer conductors made of copper foil adhered to both upper and lower sides of an insulating resin plate, and an insulating resin layer adhered to the upper and lower sides thereof, and said double-sided copper clad plate and said A plurality of through holes are formed vertically through the insulating resin layer, and a through conductor is formed on the inner wall of the through hole and a surface conductor is formed on the surface of the insulating resin layer by plating, and the inside of the through hole is formed. Is filled with a resin column, and the surface of the insulating resin layer is covered with a solder resist layer that covers a part of the surface layer conductor, and the resin column and the solder resist layer have the same composition. A wiring board which is integrally formed of resin. 2. A double-sided copper clad board having inner layer conductors made of copper foil adhered to the upper and lower sides of the insulating resin board, and an insulating resin layer applied to the upper and lower sides thereof, and the double-sided copper clad board and the insulating resin. Forming a plurality of through-holes penetrating vertically through the layer, then depositing a through-conductor on the inner wall of the through-hole and a surface conductor on the surface of the insulating resin layer by plating, respectively, and then depositing the through-hole and the insulating layer After the uncured resin having the same composition is filled and applied to the surface of the resin layer, the resin is cured to cure the resin pillar in the through hole and the resin is cured on the surface of the insulating resin layer. A method for manufacturing a wiring board, wherein the solder resist layer is integrally formed.