JP2001047423A - Composite laminate and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a composite laminate suitable for an application as a multilayer circuit board capable of advantageously forming an external conductive film finely patterned on a main surface by providing the surface having good surface roughness. SOLUTION: The composite laminate is provided by preparing a raw laminate 1 having a first sheet layer 4 containing a glass powder 3 and a second sheet layer 6 provided to give at least one main surface brought into contact with the layer 4 and containing a ceramic powder 5, heat treating the laminate 1 at a temperature capable of melting the powder 3 while sintering the powder 5 to fix the layer 4 by the molten glass 9 and impregnating the layer 5 with the powder 5 so as to fix the powder 5 to one another. Surface roughness of the main surface is influenced by a particle size of the powder 5 contained in the layer 6. Good surface roughness can be obtained by finely granulating only the powder 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite laminate and a method for producing the same, and more particularly, to a composite laminate and a method for producing the same, which are suitable for use as, for example, a multilayer circuit board and made of glass and ceramic. It is about.

[0002]

2. Description of the Related Art In recent years, miniaturization and weight reduction of chip components and the like have been progressing, and miniaturization and weight reduction of a circuit board on which such components are mounted is also desired. In order to meet such a demand, for example, a glass ceramic multilayer circuit board is effective. This is because according to the glass ceramic multilayer circuit board, high-density wiring and thinning are possible, and accordingly, downsizing and weight reduction can be achieved.

[0003] A glass ceramic multilayer circuit board is generally manufactured as follows. First, a plurality of green sheets containing both glass powder and ceramic powder are prepared, and internal conductors such as internal electrodes are formed on a specific one of the green sheets by printing or the like, and then the plurality of green sheets are laminated. After pressing and heat treatment, an external conductive film such as an external electrode is formed.

[0004]

In order to perform the above-described high-density wiring on the outer surface of the glass ceramic multilayer circuit board, fine pattern wiring must be formed on the surface of the substrate. It is essential to improve the surface roughness of the substrate.

[0005] In order to satisfy this demand, not only the ceramic powder contained in the green sheet, especially the green sheet providing the outer surface, but also the glass powder must be reduced.

However, pulverization for atomizing glass powder is not easy as compared with pulverization for atomizing ceramic powder. Therefore, the cost for obtaining the atomized glass powder is high, Glass-ceramic multilayer circuit boards that enable high-density wiring are expensive.

Accordingly, an object of the present invention is to provide a composite laminate capable of solving the above-described problems and a method for manufacturing the same, more specifically, a glass ceramic multilayer circuit board which enables relatively high-density wiring at relatively low cost. It is an object of the present invention to provide a manufacturing method thereof.

[0008]

SUMMARY OF THE INVENTION The present invention is first directed to a composite laminate. In order to solve the above-mentioned technical problems, the composite laminate according to the present invention is provided so as to be in contact with at least one first sheet layer including glass and at least the first sheet layer, and includes at least ceramic powder. A second sheet layer, at least one major surface of which is provided by the second sheet layer, and wherein the ceramic powder contained in the second sheet layer is in an unsintered state; The glass contained in one sheet layer is melted,
A part thereof penetrates the second sheet layer and is fixed to each other.

In the composite laminate according to the present invention, the first
Preferably, the sheet layer further includes a ceramic filler made of a ceramic material.

When the composite laminate according to the present invention is used for a multilayer circuit board, for example, the main surface provided by the second sheet layer constitutes a part of wiring for the multilayer circuit board. Can be advantageously used as a surface for forming an external conductive film.

Further, an internal conductor forming a part of a wiring for a multilayer circuit board may be formed inside the composite laminate.

The present invention is also directed to a method for manufacturing a composite laminate as described above. The method for producing a composite laminate according to the present invention is intended to solve the above-described technical problems.
At least one first sheet layer comprising glass;
A green laminate comprising at least one second sheet layer provided in contact with said sheet layer and comprising ceramic powder, wherein at least one major surface is provided by said second sheet layer. Heat treating the green laminate at a temperature that does not sinter the ceramic powder but can melt the glass, thereby melting the glass contained in the first sheet layer to form the first sheet layer. While being fixed, a part of the molten glass obtained by melting the glass is infiltrated into the second sheet layer, whereby
And a second step of fixing the ceramic powders to each other.

In the first step of the above-described method for producing a composite laminate, the glass contained in the first sheet layer is preferably in the form of glass powder, and the ceramic powder contained in the second sheet layer is preferably used. Has a smaller particle size than glass powder.

In the first step, the first sheet layer preferably further contains a ceramic filler made of a ceramic material.

In performing the first step, the first sheet layer is prepared in a state of a sheet that can be handled independently, and the second sheet layer is provided on the sheet for the first sheet layer. Alternatively, the first and second sheet layers are provided in the form of first and second sheets, respectively, which can be handled independently, and these first and second sheets are obtained in order to obtain a raw laminate. A second sheet may be stacked.

In the case where the method for manufacturing a composite laminate according to the present invention is directed to, for example, a method for manufacturing a multilayer circuit board, the method for manufacturing a multilayer circuit board is provided on the main surface provided by the second sheet layer. An external conductive film constituting a part of the wiring can be advantageously formed.

In the first step, the internal conductor constituting a part of the wiring for the multilayer circuit board may be formed inside the green laminate.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view for explaining an embodiment of the present invention. (1) shows a cross-sectional structure of a raw laminate 1, and (2) shows a heat treatment of the raw laminate 1. The cross-sectional structure of the composite laminate 2 obtained as described above is schematically illustrated in an enlarged manner.

Referring to FIG. 1, in order to obtain a composite laminate 2 shown in (2), a raw laminate 1 shown in (1) is prepared.

The raw laminate 1 comprises a first laminate 1 containing glass powder 3.
And a second sheet layer 6 including ceramic powder 5. The second sheet layer 6 is provided so as to be in contact with the first sheet layer 4, and in this embodiment, is located so as to sandwich the first sheet layer 4. Therefore, the outer surface of the raw laminate 1, that is, both main surfaces,
Provided by the second sheet layer 6.

Glass powder 3 contained in first sheet layer 4
As the glass constituting, for example, anorthite-based crystallized glass is advantageously used, and in addition, borosilicate glass, cordierite-based crystallized glass, and the like can be used. The particle size of the glass powder 3 does not need to be so small as compared with the particle size of the ceramic powder 5.
For example, it may be larger than the particle size of the ceramic powder 5.

The first sheet layer 4 is preferably prepared in the form of a sheet that can be handled independently, for example, a green sheet containing the glass powder 3. In order to obtain such a green sheet, a dispersion medium, a binder, and the like are mixed with the glass powder 3 to form a slurry. After removing bubbles from the slurry, sheet formation is performed on the slurry by a doctor blade method. Is done. The above-described binder, dispersion medium, and the like are illustrated as a vehicle 7 in FIG.

As the dispersion medium, water, toluene, alcohol or a mixture thereof can be used, and as the binder, butyral resin, acrylic resin, urethane resin, vinyl acetate resin, polyvinyl alcohol and the like can be used. Further, a plasticizer, a dispersant, an antifoaming agent, and the like may be added to the above-mentioned slurry as needed. In addition, extrusion molding, roll molding, powder press molding, or the like can be used for molding the green sheet.

The second sheet layer 6 is formed, for example, on the sheet for the first sheet layer 4 after the first sheet layer 4 is prepared in the state of a sheet that can be handled alone as described above. Can be molded. Therefore, a slurry containing the ceramic powder 5, the dispersion medium, the binder, and the like is prepared, and the above-mentioned sheet for the first sheet layer 4 is dipped in the slurry.

By applying the dipping method in this manner, as shown in FIG. 1, a raw laminate 1 having a second sheet layer 6 formed on both sides of a first sheet layer 4 can be efficiently obtained. it can. At this time, the ceramic powder 5 contained in the slurry
By adjusting the amount and dip time of the second
The thickness of the sheet layer 6 can be controlled.

The binder and the dispersion medium contained in the slurry for the second sheet layer 6 may be the same as the binder and the dispersion medium contained in the slurry for the first sheet layer 4 described above. May be. The binder, the dispersion medium, and the like are shown as a vehicle 8 in FIG.

Instead of the dipping method described above, a method of spray-coating a slurry containing the ceramic powder 5, a method of roll-coating, a method of printing, and the like can also be used. Further, similarly to the case of the first sheet layer 4 described above, the second sheet layer 6 is prepared in a state of a sheet that can be handled independently, and this is stacked on the sheet to be the first sheet layer 4. The raw laminated body 1 can also be obtained by this.

As the ceramic powder 5 contained in the second sheet layer 6, it is preferable to use one having good wettability with respect to the glass constituting the glass powder 3 contained in the first sheet layer 4. As the ceramic constituting the ceramic powder 5, for example, alumina is advantageously used, and in addition, MgO, ZrO ₂ , SiO ₂ , TiO _{2 and the} like can also be used.

The raw laminate 1 thus obtained is
Preferably, after being pressed in the laminating direction, it is subjected to a heat treatment step. In this heat treatment step, the ceramic powder 5
Is applied, but a temperature at which the glass constituting the glass powder 3 can be melted is applied. Therefore, this heat treatment removes vehicles 7 and 8 contained in first and second sheet layers 4 and 6, and also removes vehicles 7 and 8 from FIG.
As shown in (2), the glass 9 constituting the glass powder 3 contained in the first sheet layer 4 is melted, and the first sheet layer 4 is fixed. Further, a part of the molten glass 9 obtained by melting the glass powder 3 in this way penetrates into the second sheet layer 6 based on the capillary force, and the penetrated glass 9 fills the gap of the ceramic powder 5. The ceramic powder 5 is filled and fixed to each other.

The surface roughness of both principal surfaces of the composite laminate 2 thus obtained is governed by the particle size of the ceramic powder 5 contained in the second sheet layer 6. Therefore, even if a glass powder 3 having a relatively large particle size is used,
As long as a ceramic powder 5 having a small particle size is used, a composite laminate 2 having good surface roughness can be obtained.

Also, the finer the ceramic powder 5 contained in the second sheet layer 6 is, the more dense the second sheet layer 6 is, the lower the capillary force that causes the viscous flow of the glass 9 is. It becomes strong, and it is easy to make the filling state of the glass 9 dense.

When the glass 9 reaches the outer surface of the second sheet layer 6, it is in a molten state, and its plane is smoothed based on the surface tension.
It can also contribute to the improvement of the surface roughness of the outer surface of the second sheet layer 6, that is, each main surface of the composite laminate 2.

FIG. 2 is a diagram corresponding to FIG. 1 for explaining another embodiment of the present invention. In FIG. 2, FIG.
The elements corresponding to the elements shown in are denoted by the same reference numerals,
Duplicate description will be omitted.

In the embodiment shown in FIG. 2, in the stage of the green laminate 1a shown in (1), the first sheet layer 4a is
A ceramic filler 10 made of a ceramic material is further included in addition to the glass powder 3. In the composite laminate 2 a shown in (2), the first sheet layer 4 a
Not only that, it further includes a ceramic filler 10.

As the above-mentioned ceramic filler 10, for example, the same material as the ceramic powder 5 contained in the second sheet layer 6 can be used in the same particle size and material, but a different material may be used.

Other configurations and manufacturing methods in the embodiment shown in FIG. 2 are substantially the same as those in the embodiment shown in FIG.

As described above, if the ceramic filler 10 is contained in the first sheet layer 4a, the mechanical strength of the obtained composite laminate 2a can be further increased.

As described above, the composite laminate 2 shown in FIG.
In each of the composite laminates 2a shown in FIG. 2 and FIG. 2, the second sheet layer 6 that can provide good surface roughness by atomizing the ceramic powder 5 is located outside. Accordingly, since the composite laminate 2 or 2a is used as a circuit board, when an external conductive film is to be formed on the main surface facing outward, it can be finely patterned without any problem. , It is easy to realize high-density wiring.

Further, inside the composite laminate 2 or 2a,
An internal conductor such as an internal conductive film or a via hole connection may be formed.

FIG. 3 schematically shows a cross-sectional structure of the composite laminate 11 on which the above-described external conductive film and internal conductor are formed.

The composite laminate 11 includes a first sheet layer 12 corresponding to the above-described first sheet layer 4 or 4a and a second sheet layer 13 corresponding to the second sheet layer 6. The outer surface, that is, both main surfaces, of the composite laminate 11 is provided by the second sheet layer 13.

The composite laminate 11 has external conductive films 14, 15, 16, 17 and 18 formed on any one of its main surfaces, and has an internal conductive film as an internal conductor formed therein. 19, 20, 21, 22, 23
And 24 and via-hole connection portions 25, 26, 2
7, 28, 29 and 30.

The above-described internal conductive films 19 and 20 are formed along the interface between the first sheet layer 12 and the second sheet layer 13. Further, as can be seen from the formation positions of the internal conductive films 21 to 24 and the formation states of the via hole connection portions 27 to 30, the first sheet layer 12 is obtained by stacking a plurality of sheets at the stage of obtaining a raw laminate. Each of the plurality of sheets has a predetermined one of the internal conductive films 19 to 24 and a via-hole connection portion 25.
After the predetermined portions of ~ 30 are formed, they are stacked.

As described above, in the embodiment shown in FIG.
The first sheet layer 12 is not simply composed of one sheet at the stage of obtaining a raw laminate,
Although obtained by stacking a plurality of sheets, the same may be performed in the second sheet layer 13. In this case, it is easy to form the internal conductive film inside the second sheet layer 13.

Hereinafter, an experimental example performed to confirm the effect of the present invention will be described.

In this experimental example, as shown in Table 1,
Experimental Examples 1 to 4 and Comparative Example 1 within the scope of the present invention
5 were prepared, and the surface roughness was evaluated for each of the samples.

More specifically, as the glass powder contained in the first sheet layer, a glass powder composed of anorthite-based crystallized glass was prepared.
Those having a diameter of 50 μm were used, and in Comparative Examples 1 to 4, those having a particle diameter changed in a range of about 3.63 μm to about 7.47 μm were used. In Comparative Example 5, the first sheet layer did not contain glass powder.

On the other hand, as a ceramic filler contained in the first sheet layer, alumina powder having a particle size of about 0.35 μm was used in Examples 1-4 and Comparative Examples 1-5.

In Examples 1 to 4 and Comparative Examples 1 to 4, the prepared glass powder and ceramic filler were mixed at a weight ratio of 60:40. In, a slurry was prepared by adding water as a dispersion medium and butyral resin as a binder to only the ceramic filler. Next, after removing air bubbles from the slurry, a green sheet was produced by sheet forming by a doctor blade method. The thickness of this green sheet after drying is 50
The thickness was set to 0 μm.

On the other hand, the ceramic powder contained in the second sheet layer in Examples 1 to 4 had a particle size of about 0.35
A powder made of alumina changed in a range of μm to about 0.60 μm was prepared, and an aqueous slurry adjusted to have a solid concentration of 10% by volume was prepared using this ceramic powder.

Next, the green sheet for the first sheet layer is dipped in the above-mentioned slurry and dried to form a ceramic layer for the second sheet layer on both sides of the green sheet for the first sheet layer. Was formed with a thickness of about 10 μm.

Then, the raw laminate or green sheet of each sample was squeezed to 100 kg / cm ² by a rigid press.
And heat-treated in air at a temperature of 850 ° C. for Examples 1 to 4 and Comparative Examples 1 to 4 and a temperature of 1500 ° C. for Comparative Example 5 for 2 hours. A sample was obtained. Table 1 shows the surface roughness (Ra) of the plate-like sample according to each of these samples.

[0053]

[Table 1]

As can be seen from Table 1, the surface roughness Ra of the plate-like sample on which the second sheet layer containing the ceramic powder was formed as in Examples 1 to 4 was 0.17 μm to 0.48 μm.
m. These surface roughnesses are governed by the particle size of the ceramic powder contained in the second sheet layer. As the particle size of the ceramic powder becomes smaller,
It can be seen that the surface roughness is improved.

The effect of improving the surface roughness by Examples 1 to 4 described above is apparent from comparison with Comparative Example 3. That is, Comparative Example 3 has the same conditions as Examples 1 to 4 except that the second sheet layer is not formed. When the second sheet layer is not formed as in Comparative Example 3, the surface roughness Ra is 0.80 μm, but according to Examples 1 to 4 in which the second sheet layer is formed, Also, a better surface roughness was obtained.

In comparison between Comparative Examples 1 to 4, the smaller the particle size of the glass powder, the better the surface roughness is, but the same surface roughness as in Examples 1 to 4 is obtained. In this case, as in Comparative Example 1, the particle size of the glass powder is about 3.
The size must be reduced to about 63 μm, which increases the cost for obtaining glass powder.

As in Comparative Example 5, when the first sheet layer contains only the ceramic filler, ie, ceramic powder, and the second sheet layer is not formed, 0.2%
In this case, the heat treatment temperature must be increased to 1500 ° C., for example, the internal conductive films 19 to 24 and the via hole connection portions 25 to 30 shown in FIG. In this case, the types of metals that can be used as conductive components are limited. Further, the surface roughness which is the same as or better than the surface roughness of 0.20 μm according to Comparative Example 5 is, for example, as described in Example 1, when the particle size of the ceramic powder contained in the second sheet layer is 0.1 mm. It can be obtained by making it as small as 35 μm.

Although the present invention has been described with reference to the illustrated embodiment and the examples shown in Table 1, various other embodiments are possible within the scope of the present invention.

For example, the stacking order and number of the first sheet layer and the second sheet layer are such that the second sheet layer is provided so as to be in contact with the first sheet layer, and at least the second sheet layer is provided with the second sheet layer. As long as one main surface is provided, it can be arbitrarily changed as needed.

Further, regarding the thickness of the first sheet layer,
The thickness of the second sheet layer can be arbitrarily changed, and a part of the glass contained in the first sheet layer is melted and penetrated into the second sheet layer, and the thickness of the second sheet layer is changed. Can be arbitrarily changed as long as the ceramic powders contained in are bonded to each other.

The glass contained in the first sheet layer at the stage of the green laminate does not necessarily have to be in the form of glass powder, and may be, for example, a fiber, whisker, flake, or plate. There may be.

The present invention can also be applied to a composite laminate having a cavity whose opening is located along the outer surface. Such a cavity is formed at the stage of a green laminate, and when the composite laminate is used as a multilayer circuit board, the cavity is used to accommodate separately prepared electronic components.

[0063]

As described above, according to the present invention, the first sheet layer containing glass and the at least one second sheet layer provided in contact with the first sheet layer and containing ceramic powder are provided. And a ceramic powder contained in the second sheet layer is in a non-sintered state, and has a first surface provided by the second sheet layer.
The glass contained in the sheet layer is melted, and a part of the glass penetrates into the second sheet layer, thereby providing a composite laminate that is fixed to each other. A green laminate is provided, comprising a first sheet layer and a second sheet layer as described above, at least one major surface being provided by the second sheet layer, and then firing the ceramic powder. By heat-treating the raw laminate at a temperature at which the glass can be melted without melting the glass, the glass contained in the first sheet layer is melted to fix the first sheet layer, and the glass is melted. Part of the molten glass that has penetrated into the second sheet layer is thereby attached to the ceramic powder.

Therefore, regarding the second sheet layer, the surface condition is substantially governed only by the particle size of the ceramic powder contained in the second sheet layer.
By using the ceramic powder having a small particle size, the surface state of the second sheet layer, that is, the surface state of the main surface of the composite laminate provided by the second sheet layer is made smoother. be able to.

Therefore, if only the ceramic powder contained in the second sheet layer is atomized, the surface roughness of the main surface of the composite laminate can be improved, and the composite laminate having good surface roughness can be obtained. You can get your body at low cost.

As described above, when this composite laminate is used as a multilayer circuit board, the external conductive film formed on its main surface can be finely patterned without any problem, and as described above, it is inexpensive. In the multilayer circuit board obtained as described above, high-density wiring can be advantageously realized.

As described above, the surface condition of the main surface of the composite laminate is substantially controlled only by the particle size of the ceramic powder contained in the second sheet layer. The surface roughness of the composite laminate can be controlled by the particle size of the composite laminate.

In the method for producing a composite laminate according to the present invention, when the glass contained in the first sheet layer at the stage of the green laminate is in the state of glass powder, for example, the glass powder Even if the glass powder has a relatively large particle size, as in the case where the ceramic powder contained in the second sheet layer has a larger particle size, even if the ceramic powder has a smaller particle size, Since the surface state of the second sheet layer can be improved, it is possible to avoid an increase in cost due to pulverization for atomizing the glass powder.

In the present invention, when the first sheet layer further contains not only glass but also a ceramic filler made of a ceramic material, the mechanical strength of the composite laminate can be increased.

[Brief description of the drawings]

FIG. 1 is a view for explaining an embodiment of the present invention, in which (1) shows a cross-sectional structure of a raw laminate 1, and (2) shows a composite laminate obtained by heat-treating the raw laminate 1. It is a figure which expands and shows the cross-sectional structure of the body 2 schematically.

FIG. 2 is a view for explaining another embodiment of the present invention, in which (1) shows a cross-sectional structure of a green laminate 1a, and (2) shows a composite obtained by heat-treating the green laminate 1; It is a figure which expands and shows the cross-sectional structure of the laminated body 2a, respectively, and is illustrated.

FIG. 3 is a diagram schematically showing a cross-sectional structure of a composite laminate 11 when the present invention is applied to a multilayer circuit board.

[Explanation of symbols]

 Reference Signs List 1, 1a Raw laminate 2, 2a, 11 Composite laminate 3 Glass powder 4, 4a, 12 First sheet layer 5 Ceramic powder 6, 13 Second sheet layer 9 Glass 10 Ceramic filler 14-18 External conductive film 19-24 Internal conductive film 25-30 Via hole connection

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Shuya Nakao 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd. (72) Inventor Kenji Tanaka 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Stock Company In Murata Manufacturing (72) Inventor Masaru Kojima 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing (reference) 4G055 AA08 AC01 AC09 BA14 BA22 FA07 5E346 AA12 AA15 AA38 AA43 BB01 CC18 EE24 EE29 GG03 GG08H11 HH26

Claims (11)

[Claims] 1. At least one first sheet layer including glass, and at least one second sheet layer provided so as to be in contact with the first sheet layer and including ceramic powder. Is given by the second sheet layer, and the ceramic powder contained in the second sheet layer is:
A composite laminate in an unsintered state, wherein the glass contained in the first sheet layer is melted and a part of the glass penetrates into the second sheet layer to be fixed to each other. 2. The composite laminate according to claim 1, wherein the first sheet layer further includes a ceramic filler made of a ceramic material. 3. The composite laminate according to claim 1, further comprising an external conductive film formed on the main surface provided by the second sheet layer. 4. The composite laminate according to claim 1, further comprising an internal conductor formed inside said composite laminate. 5. The method according to claim 1, further comprising: at least one first sheet layer including glass; and at least one second sheet layer provided so as to be in contact with the first sheet layer and including ceramic powder. A first step of preparing a green laminate, at least one principal surface of which is provided by the two sheet layers; and a green laminate at a temperature that does not sinter the ceramic powder but can melt the glass. By heat-treating, the glass contained in the first sheet layer is melted to fix the first sheet layer, and a part of the molten glass obtained by melting the glass is converted to the second glass.
A second step of allowing the ceramic powder to adhere to each other and thereby adhering the ceramic powders to each other. 6. The method according to claim 1, wherein in the first step, the first
6. The composite laminate according to claim 5, wherein the glass contained in the sheet layer is in a state of glass powder, and the ceramic powder contained in the second sheet layer has a smaller particle size than the glass powder. 7. Manufacturing method. 7. The method according to claim 1, wherein in the first step, the first
The method for producing a composite laminate according to claim 5, wherein the sheet layer further includes a ceramic filler made of a ceramic material. 8. The method according to claim 1, wherein in the first step, the first
The sheet layer of (1) is prepared in a state of a sheet that can be handled alone, and the second sheet layer is formed on the sheet for the first sheet layer. 3. The method for producing a composite laminate according to item 1. 9. The method according to claim 1, wherein in the first step, the first
And the second sheet layer is provided in first and second sheets, respectively, which can be handled independently, wherein the first and second sheets are stacked to obtain the green laminate. Item 8. The method for producing a composite laminate according to any one of Items 5 to 7. 10. The method of manufacturing a composite laminate according to claim 5, further comprising a step of forming an external conductive film on the main surface provided by the second sheet layer. 11. The method of manufacturing a composite laminate according to claim 5, wherein said first step further comprises a step of forming an internal conductor inside said green laminate.