JP2001156446A - Wiring board and manufacturing method for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiring board together with its manufacturing method wherein the thickness of an inter-layer insulating layer is constant while a fine pattern is worked at an inner-layer conductor layer. SOLUTION: A copper-pasted laminated board where a copper foil 2 is pasted on both surfaces of a core substrate 1 is provided with a through hole 3. The copper foil 2 is entirely removed by etching, and both surfaces of core substrate 1 and the wall surface of through hole 3 are plated to form an inner-layer conductor layer 4. A resin-attached copper foil 6 is built up on the outside of inner-layer conductor layer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an IVH (in
The present invention relates to a wiring board having terstitial via holes) and a method of manufacturing the same.

[0002]

2. Description of the Related Art Hitherto, an IVH (interstitial via hole) has been formed in an inner layer of a wiring board to connect the inner conductor layers. Such a wiring board is manufactured as follows. That is, a through hole is made in a substrate having copper foil attached to both surfaces of an insulating layer, and panel plating is performed on the substrate. The plating layer and the copper foil function as an inner conductor layer.
Then, a filler is filled in the through hole. Then, patterning is performed on the inner conductor layer. Then, an interlayer insulating layer and an outer conductor layer are further built up on the substrate.

[0003]

However, in the above-mentioned conventional method, since the copper foil is further plated, a wiring board having a thick inner conductor layer is formed. This has the following problems.

That is, it is impossible to form a wiring board having a uniform thickness of the interlayer insulating layer. This is because the inner conductor layer below the interlayer insulating layer may be a line or a pad depending on the location. At this time, the thickness of the interlayer insulating layer thereover is different between the place where the inner conductor layer is the pad and the place where the inner conductor layer is the line. In addition, it is difficult to perform fine pattern processing on the inner conductor layer. This is because pattern thickening is inevitable due to the thick inner conductor layer. This is an obstacle to high integration of the wiring board.

The present invention has been made to solve the above problems. That is, it is an object of the present invention to provide a wiring board in which the thickness of an interlayer insulating layer is uniform and in which a fine pattern processing can be performed on an inner conductor layer, and a method of manufacturing the wiring board.

[0006]

According to the present invention, there is provided a wiring board comprising: a core substrate; inner conductor patterns on both surfaces of the core substrate; internal via holes connecting the inner conductor patterns to each other; It has an interlayer insulating layer and an outer layer conductor pattern which are respectively built up outside the both inner layer conductor patterns, and the inner layer conductor pattern is formed by directly plating the core substrate.

In the wiring board of the present invention, since the inner conductor pattern is constituted only by a layer directly plated on the core substrate, the thickness of the inner conductor pattern is small. This makes it possible to obtain a wiring board having a substantially uniform thickness of the interlayer insulating layer.
Here, "directly" means that plating is performed directly without interposing a copper foil on the core substrate. "Only" means that the inner layer conductor pattern does not include copper foil.

In the wiring board of the present invention, it is preferable to use a resin-coated copper foil as the interlayer insulating layer and the outer conductor layer.
Thereby, a wiring board having a strong peel strength of the outer conductor layer can be obtained. Further, it is desirable to use a core substrate obtained by removing copper foil on both surfaces of a substrate having copper foils adhered to both surfaces. As a result, the anchor formed when the copper foil is attached to the core substrate is used. Therefore, good adhesion between the inner conductor pattern and the core substrate can be obtained.

That is, the method for manufacturing a wiring board of the present invention comprises:
By directly forming a plating layer on both surfaces of the core substrate having a through hole and the wall surface of the through hole, performing pattern processing on the plating layer, and building up an interlayer insulating layer and an outer layer conductor pattern respectively outside the plating layer. Is the way. Accordingly, a thinner inner conductor pattern can be formed, and therefore, it is possible to cope with a fine inner conductor pattern.

Here, as described above, it is preferable to use a copper foil with a resin as the interlayer insulating layer and the outer layer conductor pattern. Further, it is desirable to use a core substrate on which copper foil is adhered on both sides and from which copper foil on both sides has been removed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. As a first embodiment, a four-layer wiring board having a two-layer IVH formed thereon and a method of manufacturing the same will be described.

First, the manufacturing method will be described. In this embodiment, a copper-clad laminate obtained by laminating copper foils 2 on both sides of a glass epoxy plate is used as a starting material.

First, a through hole 3 is formed in the copper-clad laminate (FIG. 1). Next, the copper foil 2 of the copper-clad laminate is entirely removed by etching. At this time, a copper chloride solution is used as an etching solution. Then, the glass epoxy plate is exposed.
In this embodiment, this glass epoxy plate is referred to as a core substrate 1 (FIG. 2). At this time, the surface of the core substrate 1 has fine irregularities. The irregularities are formed when the copper foil 2 is attached to the core substrate 1 in the process of manufacturing the copper-clad laminate. Next, the smear attached to the through hole 3 is removed. This smear removal is performed by treating the core substrate 1 with a potassium permanganate solution.

Then, the core substrate 1 is plated with copper. This plating is performed by applying a catalyst to the surface of the core substrate 1 and the wall surfaces of the through holes 3 to perform chemical copper plating, and then performing electrolytic copper plating thereon. Then, the inner conductor layer 4 is formed on the surface of the core substrate 1 and the wall surfaces of the through holes 3 (FIG. 3). At this time, since the wall surfaces of the through holes 3 are also plated, the inner conductor layers 4 on both surfaces of the core substrate 1 are connected by the through holes 3. Thus, the plated through hole 3 becomes a two-layer IVH 9 (see FIG. 7). In addition, since the surface of the core substrate 1 is finely uneven, the inner conductor layer 4 is securely attached to the core substrate 1 by its anchor effect.

Next, the through hole 3 is filled with a filler 5 (FIG. 4), and the inner conductor layer 4 is patterned (FIG. 5). The patterning of the inner conductor layer 4 may be performed by a known method such as forming a resist on the surface of the inner conductor layer 4 and etching the surface of the inner conductor layer 4. Then, a copper foil 6 with resin is laminated and pressed on the core substrate 1 (FIG. 6). Finally, the copper foil 8 of the copper foil 6 with resin is patterned. Thus, two layers I
A four-layer wiring board having VH9 is formed (FIG. 7).

According to the method of manufacturing a wiring board of the present embodiment, the inner conductor layer 4 is directly formed on the core substrate 1 without the copper foil 2 interposed therebetween.
, The inner conductor layer 4 can be formed thin. Therefore, fine pattern processing can be performed on the inner conductor layer 4. The core substrate 1 is obtained by etching a copper foil 2 of a copper-clad laminate. Thus, the anchor formed on the core substrate 1 can be used in the step of manufacturing the copper-clad laminate, so that the inner conductor layer 4 can be securely attached to the core substrate.

Subsequently, the 2 formed by the above method is
The configuration of the wiring board having the layer IVH will be described. This wiring board has a two-layer IVH9
Is provided. The filler 5 is filled in the two-layer IVH 9, and the inner conductor layer 4 is formed on the wall surface of the two-layer IVH 9 and on both surfaces of the core substrate 1. Further, an interlayer insulating layer 7 and a copper foil 8 are built up outside the inner conductor layer 4. The interlayer insulating layer 7 and the copper foil 8 are made of the resin-attached copper foil 6 as described above.

The inner conductor layer 4 of this wiring board is formed by plating directly on the core substrate 1 without the copper foil 2 interposed therebetween. For this reason, the thickness of the inner conductor layer 4 is small.
Therefore, the thickness of the interlayer insulating layer 7 is substantially uniform regardless of the location. Further, since the copper foil 6 with resin is used for build-up, the peel strength of the copper foil 8 is strong. This is because the peel strength of plated copper is generally about 0.7 to 1.1 kN / m, whereas the peel strength of copper foil with resin is 1.5 kN / m.
This is because it is about N / m.

(Second Embodiment) Next, as a second embodiment,
A six-layer wiring board on which four IVHs are formed and a method of manufacturing the same will be described.

First, the manufacturing method will be described. A four-layer substrate 11 is prepared as a starting material. Since the method of manufacturing the four-layer board 11 is common to the step of pressing the resin-attached copper foil 6 on the core board 1 in the first embodiment (see FIG. 6 of the first embodiment), the description thereof will be cited. Detailed description is omitted.

Next, a through hole 12 is formed in the four-layer substrate 11 shown in FIG. 6 (FIG. 8). Then, the entire copper foil 8 is removed by etching (FIG. 9). Then, the interlayer insulating layer 7 of the four-layer substrate 11 is exposed. The surface of the interlayer insulating layer 7
The anchors formed in the process of manufacturing the resin-attached copper foil 6 form fine irregularities. Next, the four-layer substrate 11
(See FIG. 10). Then, the through hole 12
The inner conductor layer 14 is formed on the wall surface of the substrate and on the outer surface of the interlayer insulating layer 7, and both surfaces of the four-layer substrate 11 are connected by the inner conductor layer 14. As a result, the through holes 12 are formed in the four-layer IVH 18 (FIG. 14).
See). At this time, the inner conductor layer 1
4 surely adheres to the interlayer insulating layer 7. Interlayer insulating layer 7
This is because the surface has fine irregularities.

Next, the through-hole 12 is filled with a filler 13 (FIG. 11), and the inner conductor layer 14 is patterned (FIG. 1).
2). A copper foil 15 with resin is provided on the outside of the four-layer substrate 11.
Is laminated and pressed (FIG. 13), and the copper foil 1 of the copper foil 15 with resin is formed.
6 is patterned. Thus, a six-layer wiring board having the four-layer IVH 18 formed thereon is completed (FIG. 14).

According to the method of manufacturing a wiring board of the present embodiment, the inner conductor layer 14 is directly plated on the interlayer insulating layer 7 without the interposition of the copper foil 8. Thereby, the inner conductor layer 14 can be formed thin. Therefore, fine pattern processing can be performed on the inner conductor layer 14. In addition, the four-layer substrate 1
The one copper foil 8 is removed by etching. Therefore,
The unevenness formed on the interlayer insulating layer 7 in the step of manufacturing the resin-attached copper foil 6 is used, and the inner conductor layer 14 can be securely attached by the anchor effect.

Next, the configuration of the six-layer wiring board formed by the above method will be described. In this wiring board, a four-layer substrate 11 is provided with a four-layer IVH 18 as shown in FIG. The filler 13 is filled in the four-layer IVH 18. Further, the copper foil 8 of the resin-coated copper foil 6 in the four-layer substrate 11 has been removed, and the inner conductor layer 14 is formed on the wall surface of the four-layer IVH 18 and on both surfaces of the four-layer substrate 11. Further, an interlayer insulating layer 17 and a copper foil 16 are built up on the outside of the inner conductor layer 14 by a copper foil 15 with resin.

In the wiring board having the above structure, the inner conductor layer 14 is plated directly on the interlayer insulating layer 7 without the interposition of the copper foil 8, so that the inner conductor layer 14 laminated on the interlayer insulating layer 7 is formed. 14 is thin. Therefore, the thickness of the interlayer insulating layer 17 is substantially uniform. Moreover, since the copper foil 15 with resin is used for build-up, the peel strength of the copper foil 16 is strong.

The present inventor conducted the following experiment in order to confirm that the thickness of the interlayer insulating layer in the wiring board of this embodiment is uniform. That is, the thickness of the inner conductor layer is 20 μm,
Three types of wiring boards of μm and 35 μm were manufactured, and in these, the thickness of the interlayer insulating layer laminated on the portion where the inner conductor layer was formed was measured. The measurement was performed at five locations for each wiring board, for a total of 15 locations. Then, the average value and the standard deviation of the measurement results were calculated. Note that a wiring board in which the thickness of the inner conductor layer is 35 μm corresponds to a conventional wiring board. Conventionally, 20 μm on a substrate on which a 18 μm thick copper foil is formed
This is because it is common to apply a certain degree of panel plating. On the other hand, a wiring board in which the thickness of the inner conductor layer is 20 μm or 27 μm corresponds to the wiring board of the present embodiment. Table 1 shows the results of experiments performed by the above method.

[0027]

[Table 1]

According to Table 1, the thickness of the inner conductor layer is 20 μm.
m and 27 μm, the thickness of the inner conductor layer is 35 μm.
Compared with the case of m, the standard deviation of the thickness in the interlayer insulating layer is significantly reduced. This indicates that the wiring board having the inner conductor layers having the thicknesses of 20 μm and 27 μm has the interlayer insulating layers laminated more uniformly. Therefore, it can be said that the wiring board of this embodiment has a more uniform interlayer insulating layer than the conventional wiring board.

As described above in detail, according to the wiring board of the present embodiment and the method of manufacturing the same, the inner conductor layers 4 and 14 are thinner than the conventional wiring board. Thereby, the thicknesses of the interlayer insulating layers 7 and 17 can be formed uniformly, and furthermore, a fine pattern processing can be performed on the inner conductor layer. In addition, since the copper foils 7 and 15 with resin are used when building up, it is possible to form a wiring board having a strong peel strength of the outer conductor layer pattern. Further, all build-up can be performed by a pressing process. In addition, by removing the copper foils 8 and 15 on both surfaces of the core substrate 1 or the four-layer substrate by etching, they are formed on the surface of the core substrate or the interlayer insulating layer 7 in the manufacturing process of the copper-clad laminate or the copper foil 6 with resin. The inner conductor layers 4 and 14 can be securely adhered to the core substrate 1 or the interlayer insulating layer 7 by utilizing the unevenness formed.

The present embodiment is merely an example and does not limit the present invention. Therefore, naturally, the present invention can be variously modified and improved without departing from the gist thereof. For example, the materials and chemicals of each part used may be different as long as they meet the purpose. Further, in the present embodiment, the wiring board on which the two-layer IVH and the four-layer IVH are formed has been described. However, the present invention can be applied to a wiring board on which a multi-layer IVH is formed.

In the first embodiment, a copper foil with resin may be further built up on the copper foil 8 to form a multilayer. At this time, the entire surface of the copper foil 8 need not be etched. Further, the same applies to the second embodiment.

[0032]

As described above, according to the present invention, there is provided a wiring board in which the thickness of the interlayer insulating layer is uniform and which can perform fine pattern processing on the inner conductor layer, and a method of manufacturing the same. Provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a core substrate and a copper foil.

FIG. 2 is a diagram showing a copper-clad laminate in which copper foil has been etched.

FIG. 3 is a diagram showing a state where a plating layer is formed.

FIG. 4 is a view showing a state in which a filler is filled in a through hole.

FIG. 5 is a diagram showing a state where a plating layer is patterned.

FIG. 6 is a view showing a state in which the copper foil with resin is pressed.

FIG. 7 is a diagram showing an example of a wiring board formed according to the present embodiment.

FIG. 8 is a diagram showing a state in which holes are formed in a four-layer substrate.

FIG. 9 is a view showing a four-layer substrate in which a copper foil is entirely etched.

FIG. 10 is a view showing a state where the entire surface is plated.

FIG. 11 is a diagram showing a state where a filler is filled.

FIG. 12 is a diagram showing a patterned state.

FIG. 13 is a view showing a state where copper foil with resin is laminated.

FIG. 14 is a diagram showing a six-layer wiring board on which four-layer IVHs are formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core board 2 Copper foil 3 Through hole 4 Plating layer 6 Copper foil with resin 7 Resin layer 8 Copper foil

Claims (6)

[Claims] 1. A core substrate, inner conductor patterns on both surfaces of the core substrate, internal via holes connecting the inner conductor patterns, an interlayer insulating layer and an outer layer respectively built up outside the both inner conductor patterns. And a conductor pattern, wherein the inner layer conductor pattern is formed by directly plating the core substrate. 2. The wiring board according to claim 1, wherein the interlayer insulating layer and the outer layer conductor pattern are formed of resin-coated copper foil. 3. The wiring board according to claim 1, wherein the core substrate is formed by removing copper foil on both surfaces of a substrate having copper foil adhered on both surfaces. Characteristic wiring board. 4. A plating layer is formed directly on both surfaces of a core substrate having a through hole and a wall surface of the through hole, a pattern processing is performed on the plating layer, and an interlayer insulating layer and an outer layer are formed outside the plating layer, respectively. A method for manufacturing a wiring board, comprising building up a conductor pattern. 5. The method for manufacturing a wiring board according to claim 4, wherein a copper foil with resin is used for build-up of the interlayer insulating layer and the outer conductor pattern. 6. The method for manufacturing a wiring board according to claim 4, wherein the core substrate is formed by removing a copper foil on both surfaces of a substrate having copper foils adhered on both surfaces. A method for manufacturing a wiring board, comprising: