JP2006128326A - Capacitor-layer forming material, manufacturing method for composite foil used for manufacture of material, and printed-wiring board with built-in capacitor circuit obtained by using capacitor-layer forming material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor-layer forming material, applicable to a printed-wiring board manufactured through a high-temperature working process at 300°C to 400°C such as a fluororesin board, a liquid-crystal polymer or the like, without strength deterioration after heating at a high temperature. <P>SOLUTION: The capacitor-layer forming material for the printed-wiring board has a dielectric layer between a first conductive layer used for forming an upper electrode and a second conductive layer used for forming a lower electrode. In the capacitor-layer forming material, a composite foil is adopted, equipped with a hard nickel plated layer, a cobalt plated layer, a nickel-cobalt alloy plated layer, and two layers of a cobalt plated layer/a hard nickel plated layer, as a metallic layer of a different kind on the surface of a copper layer in the second conductive layer. In the capacitor-layer forming material, the composite foil with two layers of an iron plated layer/the hard nickel plated layer, three layers of the cobalt plated layer/the hard nickel plated layer/the cobalt plated layer and three layers of the iron plated layer/the hard nickel plated layer/the cobalt plated layer or the like, is further adopted as the metallic layer of the different kind. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The invention according to the present application relates to a capacitor layer forming material used for forming a built-in capacitor layer of a printed wiring board, a composite foil manufacturing method used for manufacturing the capacitor layer forming material, and a built-in obtained using the capacitor layer forming material. The present invention relates to a printed wiring board including a capacitor circuit.

  A multilayer printed wiring board incorporating a capacitor circuit (element) uses one or more of the insulating layers located in the inner layer as a dielectric layer. As disclosed in Patent Document 1, an upper electrode and a lower electrode as capacitors are arranged opposite to inner layer circuits located on both surfaces of the dielectric layer to form a capacitor circuit, which has been used as a built-in capacitor. In order to form this capacitor circuit, it is common to use a capacitor layer forming material having a layer structure of first conductive layer / dielectric layer / second conductive layer similar to the double-sided copper-clad laminate. The built-in capacitor circuit is manufactured using various methods such as etching the conductive layer of the capacitor layer forming material in advance to form a capacitor circuit and bonding it to the built-in substrate or etching to the inner layer substrate. It has been.

  On the other hand, the formation of the dielectric layer is disclosed in Patent Document 3, which is a method of applying a resin composition containing a dielectric filler to a surface of a metal foil as disclosed in Patent Document 2. As described above, various production methods such as a method of laminating films containing a dielectric filler and a sol-gel method using a chemical gas phase reaction method as disclosed in Patent Document 4 have been adopted.

  As disclosed in the above patent documents, the material of the conductive layer sandwiching the dielectric layer is mainly composed of a copper component using a copper foil or the like, which improves the adhesion with the dielectric layer and at the same time. For the purpose of improving electrical characteristics such as dielectric constant, a nickel-phosphorus alloy layer may be provided on the surface of the lower electrode as seen in Patent Document 4.

And since the capacitor has made it possible to reduce the power consumption of electronic and electrical devices by storing surplus electricity, etc., it is required as a basic quality to have as large an electric capacity as possible. The capacitance (C) of the capacitor is calculated from the equation C = εε ₀ (A / d) (ε ₀ is the dielectric constant of vacuum). In particular, due to the recent trend of light and thin electronic and electrical equipment, the same demands will be made on printed wiring boards, and it is not possible to take a large capacitor electrode area within a certain printed wiring board area. It is almost impossible and it is clear that there is a limit to the improvement in terms of surface area (A). Therefore, in order to increase the capacitor capacity, if the surface area (A) of the capacitor electrode and the relative dielectric constant (ε) of the dielectric layer are constant, the thickness (d) of the dielectric layer is reduced, or the capacitor Attempts have been made to devise the layer structure when viewed as a circuit as a whole.

  Further, in recent years, highly integrated IC chips, high-speed signal transmission speeds ranging from the giga level to the tera level have been required, the heat generated from the printed wiring board has increased, and there are demands for various high-frequency characteristics. Has been made. In order to meet the demand, printed wiring board production using a fluororesin substrate, a liquid crystal polymer, or the like as a substrate material as disclosed in Patent Document 5 and Patent Document 6 has also been activated.

JP 2003-105205 A JP 9-040933 A JP 2004-250687 A US Pat. No. 6,541,137 JP 2003-171480 A JP 2003-124580 A

  However, considering that the capacitor layer forming material has a layer configuration of the first conductive layer / dielectric layer / second conductive layer, to make the dielectric layer thin means that the thickness of the capacitor layer forming material itself is thin. Therefore, there is a disadvantage that the strength cannot be maintained, the probability of damage such as breakage during handling is high, and the safety during handling is lacking.

  Further, as disclosed in Patent Document 4, when the dielectric layer is formed by the sol-gel method, a sol-gel film for forming the dielectric layer is formed on the surface of the metal foil, and 600 ° C. It was necessary to fire at a temperature in the vicinity, and the phenomenon that the metal foil was oxidized and embrittled occurred. Furthermore, when a nickel-phosphorus alloy layer is provided on the surface of the lower electrode, there is a problem in the adhesion between the dielectric layer and the nickel-phosphorus alloy layer, and there is a problem between the dielectric layer and the nickel-phosphorus alloy layer. A peeling phenomenon may occur, and the deviation from the design electric capacity as a capacitor becomes large and the design quality is not satisfied. In addition, delamination occurs as a printed wiring board, causing delamination due to heat shocks such as solder reflow, and causing heat generation during use to shorten the product life. It was.

  On the other hand, in place of the conventional glass-epoxy substrate, in consideration of high temperature heat resistance, high frequency characteristics, etc., a fluororesin substrate, a liquid crystal polymer, etc. are used as a substrate material, and production of a multilayer substrate using these is attempted. ing. And what is common to these substrate manufactures is that the press working temperature is extremely high, being between 300 ° C. and 400 ° C., and the substrate material is hard. Therefore, in consideration of forming a built-in capacitor layer inside a multilayer printed wiring board using such a fluororesin substrate, a liquid crystal polymer or the like as a substrate material, a hard substrate material is subjected to a high temperature pressing at 300 ° C. to 400 ° C. It is desirable that the material does not fluctuate in material even when pressed, and has a strength sufficient to withstand expansion and contraction of surrounding materials.

  Therefore, the market has a conductive layer for forming a new lower electrode that has excellent adhesion to the dielectric layer as the lower electrode of the capacitor circuit and can be used as a resistor electrode, etc. Therefore, a capacitor layer forming material has been demanded. At the same time, there has been a demand for a capacitor layer forming material that does not deteriorate in strength even after a high temperature processing process of 300 ° C. to 400 ° C. on a printed wiring board using a fluororesin substrate, a liquid crystal polymer, or the like as a substrate material.

  Therefore, as a result of diligent research, the present inventors have obtained good adhesion between the dielectric layer and the lower electrode by using the following capacitor layer forming material, and even if the dielectric layer becomes thin, the capacitor layer It was conceived that the strength of the forming material was maintained and the handling property was improved. Moreover, it is a capacitor layer forming material that does not deteriorate in strength even after a high temperature processing process of 300 ° C. to 400 ° C. in a printed wiring board using a fluororesin substrate, a liquid crystal polymer, etc. as a substrate material. By using the forming material, the electric capacity as the capacitor circuit is also reliably improved.

<Capacitor layer forming material according to the present invention>
FIG. 1 shows a schematic cross section of a capacitor layer forming material. As can be seen from FIG. 1, the capacitor layer forming material 1 includes a dielectric layer 3 between a first conductive layer 2 used for forming an upper electrode and a second conductive layer 4 used for forming a lower electrode. The capacitor layer forming material according to the present invention is characterized by using various composite foils for the second conductive layer 4 used for forming the lower electrode. That is, this composite foil has a copper layer provided with one dissimilar metal layer (hereinafter referred to as “first composite foil”), and a copper layer provided with two dissimilar metal layers. Can be roughly divided into three types (hereinafter referred to as “second composite foil”) and those provided with three different metal layers on the surface of the copper layer (hereinafter referred to as “third composite foil”). . Therefore, the capacitor layer forming material is also classified into each of the first capacitor layer forming material, the second capacitor layer forming material, and the third capacitor layer forming material according to the type of composite foil used for the configuration of the second conductive layer 4. I will explain.

<First capacitor layer forming material>
This first capacitor layer forming material is obtained using the first composite foil. Here, the basic layer configuration of the first capacitor layer forming material 1a is as shown in FIG. 1, and various composite foils are used for the second conductive layer 4, and the following three types of composite foils are used. There are basic variations.

Variation 1-i: In a capacitor layer forming material for a printed wiring board comprising a dielectric layer between a first conductive layer used for upper electrode formation and a second conductive layer used for lower electrode formation, the second conductive layer is a copper layer A capacitor layer forming material using a composite foil having a hard nickel plating layer as a different metal layer on the surface thereof.

Variation 1-ii: In the capacitor layer forming material of the printed wiring board including a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode, the second conductive layer is a copper layer A capacitor layer forming material comprising a composite foil having a cobalt plating layer as a dissimilar metal layer on the surface thereof.

Variation 1-iii: In a capacitor layer forming material for a printed wiring board comprising a dielectric layer between a first conductive layer used for forming an upper electrode and a second conductive layer used for forming a lower electrode,
The second conductive layer is a capacitor layer forming material using a composite foil having a nickel-cobalt alloy plating layer as a different metal layer on the surface of a copper layer.

  As is apparent from the above description, the first composite foil 5a includes a single dissimilar metal layer 6 on the surface of the copper layer C as shown in FIG. However, as shown in FIGS. 2A and 2B, the dissimilar metal layer 6 can be provided on one side or both sides of the copper layer. The surface of the first composite foil 5a on which the dissimilar metal is formed becomes the contact surface with the dielectric layer 3. This is because the presence of dissimilar metals can improve the adhesion to the dielectric layer.

Here, the first composite foil 5a has a hard nickel plating layer, a cobalt plating layer, a nickel-cobalt alloy plating layer (in the above and the following, for convenience of explanation, as a different metal layer 6 on the surface of the copper layer. In some cases, it is referred to as a “layer”. Here, as shown in FIG. 2B, either a hard nickel plating layer, a cobalt plating layer, or a nickel-cobalt alloy plating layer (hereinafter referred to as a “hard nickel plating layer or the like”) is formed on both sides of the copper layer. These are excellent in heat resistance characteristics, softening hardly occurs when heated at 400 ° C. for about 10 hours, and effectively suppresses a decrease in tensile strength (strength) when viewed as a composite foil as a whole, This is because it is easy to set the tensile strength after heating to 48 kgf / mm ² or more. As long as such physical properties are provided, there is almost no deterioration in strength even after a high temperature processing process of 300 ° C. to 400 ° C. on a printed wiring board using a fluororesin substrate, a liquid crystal polymer, etc. as a substrate material. The quality deterioration of the capacitor layer forming material manufactured using the 1 composite foil 5a is hardly caused. In addition, this hard nickel plating layer etc. was provided on both sides of the copper layer, considering the use of copper foil for forming the copper layer, even if the hard nickel plating layer etc. were provided on one side, the physical strength such as tensile strength Although the characteristics and curling phenomenon are suppressed and handling properties are improved, the coating with excellent oxidation resistance such as hard nickel plating is present on both sides, thereby preventing the oxidative corrosion of the copper layer itself and further curling phenomenon. This is because suppression can be achieved. In addition, the hard nickel plating layer said to this invention is refined | miniaturized to the level whose average crystal grain diameter is 0.3 micrometer or less in a crystal grain, and is equipped with the physical property with high mechanical strength.

  And when using copper foil for formation of a copper layer, it is possible to use electrolytic copper foil or rolled copper foil, and it is preferable to use that whose nominal thickness is 1 micrometer-35 micrometers. In recent years, with the demands for downsizing, weight reduction, and thinning of electronic devices and the like in which printed wiring boards are used, printed wiring boards also tend to be thinned. Therefore, considering the provision of a hard nickel plating layer or the like on the copper foil surface, the thickness is set to 1 μm to 35 μm. If the nominal thickness of the copper foil is less than 7 μm, it becomes difficult to form a hard nickel plating layer or the like directly on the copper foil of that thickness, and the product yield is drastically deteriorated. Therefore, in such a case, use copper foil with carrier foil, form hard nickel plating etc. on one side of the copper foil layer, and after processing such as pasting to the substrate as it is, peel off the carrier foil and copper foil It is preferable to form a hard nickel plating layer or the like on the opposite surface of the layer. On the other hand, when the nominal thickness of the copper foil exceeds 35 μm, it is not preferable because the thickness of the composite foil including a hard nickel plating layer exceeds the appropriate thickness required for the current capacitor layer forming material.

  Next, the thickness of the hard nickel plating layer or the like is preferably 0.5 μm to 3.0 μm. When the thickness of the plating layer is less than 0.5 μm, the strength sufficient to improve the handling property when the dielectric layer becomes thin is not obtained, and at the same time, when trying to use a hard nickel plating layer or the like for a resistance circuit or the like The lack of performance. On the other hand, even if the thickness of the hard nickel plating layer or the like exceeds 3.0 μm, the handleability of the capacitor layer forming material when processed into the capacitor layer forming material is not significantly improved. This is because a large amount of expensive components are used.

  Moreover, when using an electrolytic copper foil as a copper layer, it is preferable to make the thickness of the hard nickel plating layer etc. provided in the surface of a rough surface and a glossy surface different. This is to prevent the occurrence of the curl phenomenon described above. For example, if a 2.5 μm thick hard nickel plating layer or the like is provided on the glossy surface of a 12 μm nominal thickness electrolytic copper foil, a 3.5 μm thick hard nickel layer or the like is provided on the rough surface side. is there. At this time, assuming that the thickness of the hard nickel plating layer or the like provided on the glossy surface side is t (μm), the thickness of the hard nickel plating layer or the like provided on the rough surface side is t + 0.5 (μm) to t + 1.2 (μm). It is preferable that If the thickness of the hard nickel plating layer or the like provided on the rough surface side is less than t + 0.5 (μm), the effect of suppressing the curling phenomenon cannot be obtained, and if it exceeds t + 1.2 (μm) The tendency of the curling phenomenon reversed to that of the electrolytic copper foil is increased.

The first composite foil described above exhibits sufficient anti-softening performance and a tensile strength of 50 kgf / mm ² or more even when heated at 400 ° C. for about 10 hours. Therefore, the mechanical properties do not change at all at the high temperature press at around 180 ° C. employed when producing a copper clad laminate. However, when press conditions at temperatures exceeding 400 ° C. are required, it is preferable to employ a cobalt plating layer or a nickel-cobalt alloy plating layer rather than a hard nickel plating layer. When heated at a temperature exceeding 400 ° C., the hard nickel layer alone tends to cause mutual diffusion with the copper foil layer, and the hard nickel layer itself cannot maintain the anti-softening property, and toughness as a capacitor forming material. Is reduced and handling is lacking.

  The capacitor layer forming material is manufactured using the first composite foil described above. The manufacturing method of the first composite foil and the capacitor layer forming material described here will be described in detail in the embodiment.

<Second capacitor layer forming material>
This second capacitor layer forming material is obtained using the second composite foil. Here, the basic layer configuration of the second capacitor layer forming material is as shown in FIG. 3, and various composite foils are used for the second conductive layer 4, and the following two types of composite foils are used. There are basic variations.

Variation 2-i: In the capacitor layer forming material for a printed wiring board having a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode, the second conductive layer is a copper layer A capacitor layer forming material comprising a composite foil comprising two different metal layers laminated in order of a cobalt plating layer / a hard nickel plating layer on the surface of the substrate.

Variation 2-ii: In the capacitor layer forming material for a printed wiring board having a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode, the second conductive layer is a copper layer A capacitor layer forming material comprising a composite foil having two different metal layers laminated on the surface of an iron plating layer / hard nickel plating layer in sequence.

  As is apparent from the above, the second composite foil 5b includes two different metal layers 6a and 6b on the surface of the copper layer as shown in FIG. However, as shown in FIG. 2, the dissimilar metal layers 6a and 6b can be provided on one side or both sides of the copper layer. The surface of the second composite foil 5b on which the dissimilar metal is formed becomes the contact surface with the dielectric layer 3. This is because the presence of the dissimilar metal layer can improve the adhesion to the dielectric layer.

  The 2nd composite foil 5b said here is equipped with the cobalt plating layer or the iron plating layer as the different metal layer 6a on the surface of the copper layer, and the hard nickel plating layer as another different metal layer 6b on the surface. is there. Here, as shown in FIG. 2B, the dissimilar metal layer 6 may be provided on both surfaces of the copper foil, as in the case of the first composite foil 5a.

  The second composite foil 5b referred to in the present invention is a composite in which a dissimilar metal layer 6a (cobalt plating layer or iron plating layer) and a dissimilar metal layer 6b (hard nickel plating layer) are sequentially formed on the surface of the copper foil C. It is a foil. As apparent from FIG. 2, the different metal layer 6a comes into contact with the surface of the copper layer at this time, and the different metal layer 6b (hard nickel plating layer) exists on the surface of the different metal layer 6a. It is. Such a laminated arrangement is adopted because a hard nickel plating layer exists on the surface of the copper layer and a cobalt plating layer is sequentially formed on the hard nickel plating layer. When heated for a long time at a temperature of (C), the boundary between the hard nickel plating layer and the copper foil layer moves due to mutual diffusion, resulting in the Kirkendall effect and the expansion of the copper-nickel alloy region into the copper layer As a result, the high tensile strength that the hard nickel plating layer should have cannot be maintained. And, when the Carkendar effect occurs, it is known that voids are generated at the diffusion boundary, and if there are microscopic defects such as voids, it becomes a concentration point of tensile stress when measuring tensile strength, The foil breaks easily.

  Here, the optical microscope observation photograph which caught generation | occurrence | production of the said Kirkendall effect shall be shown. First, the cross-sectional state before and after heating was observed using a composite copper foil in which a cobalt plating layer and a hard nickel plating layer were sequentially laminated on both sides of the copper foil. As a result, there was no particularly significant difference between the cross-sectional observation photograph with the optical microscope before heating shown in FIG. 5 and the cross-sectional observation photograph with the optical microscope after heating at 400 ° C. for 10 hours in FIG. It was found that there was no change in the cross-sectional state. On the other hand, when a cross-sectional state before and after heating is observed using a composite copper foil (first composite copper foil) in which only a hard nickel plating layer is formed on both surfaces of the copper foil, a remarkable difference is recognized. FIG. 7 shows a cross-sectional observation photograph with an optical microscope before heating the first composite copper foil, and FIG. 8 shows a cross-sectional observation photograph with an optical microscope after heating at 400 ° C. for 10 hours. When FIG. 7 and FIG. 8 are compared, in the cross-sectional observation photograph after heating, a void-like shape is observed inside the copper foil (location indicated by an arrow in FIG. 8). This void is considered to be generated by the Kirkendall effect in which the boundary between the hard nickel plating layer and the copper foil layer is moved by mutual diffusion by heating. Therefore, as long as the capacitor layer forming material manufactured using the second composite foil is used, a high-quality built-in capacitor layer can be formed in a multilayer printed wiring even if a press condition of around 400 ° C. is adopted in the future. It can be manufactured inside the plate.

  The thickness of the dissimilar metal layer 6a (cobalt plating layer or iron plating layer) constituting the second composite foil is 0.1 μm to 0.5 μm, and the thickness of the hard nickel plating layer is 0.3 μm to 2.5 μm. Is preferred. The reason for adopting such a layer configuration is to reduce the amount of expensive cobalt used as much as possible and to obtain anti-softening characteristics equivalent to those obtained by plating a cobalt single layer. Therefore, when the thickness of the dissimilar metal layer 6a is less than 0.1 μm, it cannot contribute to the barrier layer between the hard nickel plating layer and the copper layer, and the occurrence of the above-mentioned Kendall effect cannot be prevented. The difference between the case where the dissimilar metal layer 6a is not adopted when received is not generated. On the other hand, if the thickness of the dissimilar metal layer 6a exceeds 0.5 μm, it is no different from providing a cobalt plating layer as a single layer, and the significance of providing the dissimilar metal layer 6a and the hard nickel plating layer is lost. is there. And when the thickness of a hard nickel plating layer is less than 0.3 micrometer, it does not contribute to the effect of reinforcing the dissimilar metal layer 6a and improving an anti-softening characteristic. On the other hand, if the thickness of the hard nickel plating layer exceeds 2.5 μm, the economic efficiency is impaired, and the significance of adopting the two-layer configuration is lost.

The second composite foil described above also exhibits sufficient anti-softening performance when heated at 400 ° C. for about 10 hours, and exhibits a tensile strength of 50 kgf / mm ² or more. As long as such physical properties are provided, there is almost no deterioration in strength even after a high temperature processing process of 300 ° C. to 400 ° C. on a printed wiring board using a fluororesin substrate, a liquid crystal polymer, etc. as a substrate material. 2 The quality deterioration of the capacitor layer forming material manufactured using the composite foil 5b is hardly caused.

  The capacitor layer forming material is manufactured using the first composite foil described above. The manufacturing method of the second composite foil and the capacitor layer forming material described here will be described in detail in the embodiment.

<Third capacitor layer forming material>
This third capacitor layer forming material is obtained using the third composite foil. Here, the basic layer configuration of the third capacitor layer forming material is as shown in FIG. 9, and various composite foils are used for the second conductive layer 4, and the following two types of composite foils are used. There are basic variations.

Variation 3-i: In the capacitor layer forming material for a printed wiring board having a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode, the second conductive layer is a copper layer A capacitor layer forming material comprising a composite foil comprising three different metal layers laminated in order of a first cobalt plating layer / a hard nickel plating layer / a second cobalt plating layer on the surface thereof.

Variation 3-ii: In a capacitor layer forming material for a printed wiring board comprising a dielectric layer between a first conductive layer used for upper electrode formation and a second conductive layer used for lower electrode formation, the second conductive layer is a copper layer A capacitor layer-forming material comprising a composite foil comprising three different metal layers laminated in order of an iron plating layer / hard nickel plating layer / cobalt plating layer on the surface of the substrate.

  That is, the third composite foil 5c includes three different metal layers 6a, 6b and 6c on the surface of the copper layer as shown in FIG. However, as shown in FIG. 10, the dissimilar metal layers 6a, 6b, 6c can be provided on one side or both sides of the copper layer. The surface of the third composite foil 5c on which the dissimilar metal is formed becomes a contact surface with the dielectric layer 3. This is because the presence of dissimilar metals can improve the adhesion to the dielectric layer.

  The third composite foil 5c mentioned here includes a first cobalt plating layer as the dissimilar metal layer 6a on the surface of the copper layer, a hard nickel plating layer as the dissimilar metal layer 6b on the surface, and a dissimilar metal layer on the surface thereof. 6a provided with a second cobalt plating layer. Alternatively, the third composite foil 5c includes an iron plating layer as the dissimilar metal layer 6a on the surface of the copper layer, a hard nickel plating layer as the dissimilar metal layer 6b, and cobalt as the dissimilar metal layer 6a on the surface. A plating layer is provided. Here, as shown in FIG. 10B, the dissimilar metal layer 6 may be provided on both surfaces of the copper layer, as in the case of the first composite foil 5a.

  The third composite foil 5c referred to in the present invention is formed on the surface of the copper layer C by dissimilar metal layer 6a (first cobalt plating layer or iron plating layer), dissimilar metal layer 6b (hard nickel plating layer) and dissimilar metal layer 6c ( This is a composite foil in which (second) cobalt plating layer) is sequentially formed. As apparent from FIG. 10, the surface of the copper layer at this time is in contact with the dissimilar metal layer 6a, the dissimilar metal layer 6b on the surface of the dissimilar metal layer 6a, and the dissimilar metal layer on the surface thereof. 6c exists. The reason why such a laminated arrangement is adopted is to prevent the occurrence of the same Kakendal effect as described above and to maintain the strength of the foil even after high temperature load. In addition, if a cobalt layer is present in the outermost layer, the high temperature heat resistance is improved.

  The thickness of the dissimilar metal layer 6a (first cobalt plating layer or iron plating layer) constituting the third composite foil is 0.1 μm to 0.5 μm, and the thickness of the hard nickel plating layer of the dissimilar metal layer 6b is 0.3 μm. The thickness of the (second) cobalt plating layer of the dissimilar metal layer 6c is preferably 0.1 μm to 0.5 μm. The reason for adopting such a layer configuration is almost the same as that of the second composite foil. When the thickness of the dissimilar metal layer 6a is less than 0.1 μm, it contributes as a barrier layer between the hard nickel plating layer and the copper layer. It is not possible to prevent the occurrence of the above-mentioned Kerr-Kendall effect, and there is no difference from the case where the dissimilar metal layer 6a is not employed particularly when it is heated to over 400 ° C. On the other hand, if the thickness of the dissimilar metal layer 6a exceeds 0.5 μm, it is no different from providing a cobalt plating layer as a single layer, and the significance of providing other dissimilar metal layers 6b and 6c is lost. When the thickness of the dissimilar metal layer 6b (hard nickel plating layer) is less than 0.3 μm, it does not contribute to the effect of reinforcing the dissimilar metal layer 6a and improving the anti-softening property. On the other hand, if the thickness of the dissimilar metal layer 6b (hard nickel plating layer) exceeds 2.5 μm, the economical efficiency is impaired and the significance of adopting the three-layer configuration is lost. Further, when the thickness of the dissimilar metal layer 6c ((second) cobalt plating layer) is less than 0.3 μm, it cannot contribute to the improvement of oxidation resistance, and the dissimilar metal layer 6b is reinforced to improve the anti-softening property. It does not contribute to the effect to be made. On the other hand, if the thickness of the dissimilar metal layer 6c ((second) cobalt plating layer) exceeds 2.5 μm, the economic efficiency is impaired and the significance of adopting the three-layer configuration is lost.

The third composite foil 5c described above also exhibits sufficient anti-softening performance when heated at about 400 ° C. for about 10 hours, and exhibits a tensile strength of 50 kgf / mm ² or more. As long as such physical properties are provided, there is almost no deterioration in strength even after a high temperature processing process of 300 ° C. to 400 ° C. on a printed wiring board using a fluororesin substrate, a liquid crystal polymer, etc. as a substrate material. The quality deterioration of the capacitor layer forming material manufactured by using the three composite foils 5c is hardly caused.

  The capacitor layer forming material is manufactured using the third composite foil described above. The manufacturing method of the third composite foil and the capacitor layer forming material described here will be described in detail in the embodiment.

<The manufacturing method of the composite foil used for manufacture of the capacitor layer forming material which concerns on this invention>
Among the first composite copper foils, the manufacture of a composite foil comprising a hard nickel plating layer as a different metal layer on the surface of the copper layer is performed by immersing the copper foil in a hard nickel electrolytic plating bath having the following composition, and the following electrolysis conditions: It is preferable to employ a production method characterized in that electrolytic plating is performed to form a hard nickel plating layer.

[Hard nickel plating bath composition]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 3-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring

  Among the first composite copper foils, the production of a composite foil having a cobalt plating layer as a different metal layer on the surface of the copper layer is performed by immersing the copper foil in a cobalt sulfate electroplating bath having the following composition, under the following electrolysis conditions: It is preferable to employ a manufacturing method characterized by performing electrolytic plating to form a cobalt plating layer. Further, it is also preferable that the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l.

[Cobalt plating bath composition]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring

  Among the first composite copper foils, the production of a composite foil having a nickel-cobalt alloy plating layer as a different metal layer on the surface of the copper layer is performed by immersing the copper foil in a nickel-cobalt alloy electrolytic plating bath having the following composition. It is preferable to employ a manufacturing method characterized in that electrolytic plating is performed under the following electrolysis conditions to form a nickel-cobalt alloy plating layer.

[Nickel-cobalt alloy electroplating bath]
_{NiSO 4 · 6H 2 O 100g /} l~200g / l
NiCl ₂ · 6H ₂ O 30 g / l to 50 g / l
CoSO ₄ · 7H ₂ O 10 g / l to 30 g / l
H ₃ BO ₃ 20 g / l to 40 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 25 A / dm ²
There is stirring

  Among the second composite copper foils, the manufacture of a composite foil comprising two layers of a cobalt plating layer / hard nickel plating layer as a dissimilar metal layer on the surface of the copper layer, And immersed in a cobalt sulfate electrolytic plating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions, and the cobalt plating layer is formed, the following B. A hard nickel electrolytic plating bath having the composition of It is preferable to employ a method for producing a composite foil characterized in that the electroplating is performed under the above electrolysis conditions to form a hard nickel plating layer. Further, it is also preferable that the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l.

[A. Composition, electrolysis conditions]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring

  Among the second composite copper foils, the production of a composite foil comprising two layers of an iron plating layer / hard nickel plating layer as a dissimilar metal layer on the surface of the copper layer is carried out using And immersed in an iron sulfate electroplating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions, and the iron plating layer is formed, the following B. A hard nickel electrolytic plating bath having the composition of It is preferable to employ a method for producing a composite foil characterized in that the electroplating is performed under the above electrolysis conditions to form a hard nickel plating layer. Furthermore, it is also preferable to include a flocculant in the iron sulfate electroplating bath at a concentration of 0.05 g / l to 0.3 g / l.

[A. Composition, electrolysis conditions]
FeSO ₄ · 7H ₂ O 100 g / l to 200 g / l
H ₃ BO ₃ 20 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 30 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring

  Among the above-mentioned third composite copper foils, the manufacture of a composite foil comprising three layers of a first cobalt plating layer / hard nickel plating layer / second cobalt plating layer as a different metal layer on the copper layer surface is described below. A. And immersed in a cobalt sulfate electrolytic plating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions of (1) to form the first cobalt plating layer, the following B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is carried out under the electrolysis conditions to form a hard nickel plating layer. And immersed in a cobalt sulfate electrolytic plating bath having the following composition: It is preferable to employ a method for producing a composite foil, characterized in that the second cobalt plating layer is formed by performing electrolytic plating under the electrolytic conditions. Moreover, it is also preferable that the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l.

[A. Composition, electrolysis conditions]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring

  Among the third composite copper foils, the manufacture of a composite foil comprising three layers of an iron plating layer / hard nickel plating layer / cobalt plating layer as a different metal layer on the surface of the copper layer is carried out using And immersed in an iron sulfate electroplating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions, and the iron plating layer is formed, the following B. A hard nickel electrolytic plating bath having the composition of The electroplating is performed under the electrolysis conditions to form a hard nickel plating layer. The following C.I. It is preferable to employ a method for producing a composite foil characterized in that the electroplating is performed under the above electrolysis conditions to form a cobalt plating layer. Moreover, it is also preferable that the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l.

[A. Composition, electrolysis conditions]
FeSO ₄ · 7H ₂ O 100 g / l to 200 g / l
H ₃ BO ₃ 20 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 30 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
With stirring [C. Composition, electrolysis conditions]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring

<Printed wiring board with built-in capacitor circuit>
Using any one of the capacitor layer forming materials according to the present invention, a printed wiring board having a built-in capacitor circuit can be manufactured using various methods. The capacitor circuit built in the printed wiring board thus obtained has a high temperature and heat resistant property in the second conductive layer constituting the lower electrode even if it is repeatedly subjected to hot pressing in the range of 300 ° C. to 400 ° C. Since the above composite foil is excellent, the lower electrode has no abnormality, and has resistance to the expansion and contraction behavior of the surrounding material due to heat. Therefore, it is suitable for forming a built-in capacitor circuit of a multilayer printed wiring board using a fluororesin substrate or a liquid crystal polymer substrate.

  Since the capacitor layer forming material according to the present invention includes the composite foil having excellent high-temperature heat resistance in the second conductive layer constituting the lower electrode, the multilayer printed wiring board using the fluororesin substrate and the liquid crystal polymer substrate is used. Even if hot pressing in the range of 300 ° C. to 400 ° C. used for manufacturing is repeated, no abnormality occurs in the shape of the lower electrode even after the capacitor circuit shape is formed, and expansion and contraction due to the heat of surrounding materials Has resistance to behavior. In addition, since the combination of different metal layers and layer configurations of the composite foil can be appropriately selected according to the type of dielectric layer, it is possible to maintain good adhesion between the dielectric layer and the lower electrode. It becomes. As a result, the printed wiring board provided with the built-in capacitor circuit obtained by using the capacitor layer forming material according to the present invention is of high quality. Also, in the method for manufacturing a composite foil used for manufacturing a capacitor layer forming material according to the present invention, a dissimilar metal layer having excellent heat resistance is provided on the surface of the copper foil by adopting constant plating conditions for the dissimilar metal layer. Can do. Using this composite foil, the capacitor layer forming material according to the present invention can be manufactured based on a conventional method.

  Hereinafter, the manufacturing mode of each composite foil according to the present invention will be described, the manufacturing mode of the capacitor layer forming material according to the present invention will be described, and the manufacturing up to the printed wiring board provided with the built-in capacitor circuit will be referred to in the examples.

<Production form of composite foil>
First composite foil (1): Among the first composite foils, the one having a hard nickel plating layer as a dissimilar metal layer on the surface of the copper layer employs a hard nickel electrolytic plating bath having the above-described composition using a copper foil. It is preferable to do. This is because a hard nickel plating layer having excellent anti-softening properties after heating at the highest temperature can be obtained. The hard nickel electrolytic plating bath used in the present invention has a composition close to that of a watt bath, but a simpler composition than a general watt bath and a plating solution composition capable of stable electrolysis. is doing. Among them, the characteristic is that a nickel salt and an ammonium salt coexist in the bath.

Here, the concentration of NiSO ₄ .6H ₂ O is desirably 100 g / l to 180 g / l. When the concentration of NiSO ₄ .6H ₂ O is less than 100 g / l, the nickel concentration in the plating solution becomes dilute, and not only industrial productivity is not satisfied, but also the smoothness of the plating surface is inferior. And even if the concentration of NiSO ₄ .6H ₂ O exceeds 180 g / l, the precipitation rate of hard nickel does not change greatly, but rather the load of waste liquid treatment increases.

H ₃ BO ₃ plays a role as a buffer. The concentration of H ₃ BO ₃ is desirably in the range of 20 g / l to 60 g / l. This H ₃ BO ₃ concentration is determined by the relationship with the concentration of NiSO ₄ .6H ₂ O described above, and if it is outside this range, the strength of the hard nickel plating layer itself will be insufficient.

The liquid temperature can employ a wide range of 20 ° C to 50 ° C. This is because there is little influence on the tensile strength due to the liquid temperature as in a normal nickel acetate bath or sulfamic acid bath. And when it is set as the solution of the above-mentioned composition, pH 3-5 can obtain the plating film with the best tensile strength and stable. Furthermore, the current density at the time of plating can employ a wide range of 1 A / dm ^{2 to} 50 A / dm ² . This is because there is little influence on the tensile strength due to the current density as in the nickel acetate bath. In particular, considering that the tensile strength of the hard nickel plating layer itself is increased, it is desirable to adopt a current density of 4 A / dm ² or less, or a range of 10 A / dm ² or more. ^{Then, 4A / dm 2 ~10A / dm} 2 of the range tend to be lowest tensile strength as hard nickel plating layer, and the value of the predetermined levels without significant changes in tensile strength at the current density range Tend to be. Accordingly, when importance is attached to ensuring the quality stability of the ^product, it is the preferred to employ a range of ^{4A / dm 2 ~10A / dm 2} . The content described above is based on the premise that the stirring bath is used to stir the plating solution. Stirring as referred to in the present invention is required to stir enough to eliminate the ion-deficient layer in the vicinity of the surface to be plated during electrodeposition. For example, when stirring is performed by placing a stirrer in the plating tank, plating is performed. It is described as a concept including a fluid stirring state created by liquid circulation.

First composite foil (2): Among the first composite foils, those having a cobalt plating layer as a dissimilar metal layer on the copper layer surface can be produced as long as the cobalt plating layer can be formed on the copper foil surface. Various methods can be employed. For example, a) Using cobalt sulfate, the cobalt concentration is 5-30 g / l, trisodium citrate 50-500 g / l, liquid temperature 20-50 ° C., pH 2-4, current density 0.3-10 A / dm ² B) Using cobalt sulfate, the cobalt concentration is 5-30 g / l, potassium pyrophosphate 50-500 g / l, liquid temperature 20-50 ° C., pH 8-11, current density 0.3-10 A / dm ² , c ) Using cobalt sulfate, the cobalt concentration is 10 to 70 g / l, boric acid 20 to 60 g / l, liquid temperature 20 to 50 ° C., pH ^{2 to} 4 and current density 1 to 50 A / dm ² .

  However, in the present invention, it is most preferable to employ a cobalt sulfate electrolytic plating bath having the above composition. This is because the cobalt plating layer having the best anti-softening property after high-temperature heating can be obtained. The present invention employs a cobalt sulfate electrolytic plating bath in which nickel sulfate in the nickel sulfate bath used to form the hard nickel plating layer used in the production of the first composite foil is replaced with cobalt sulfate and a flocculant is added thereto. Yes.

Here, the concentration of CoSO ₄ .7H ₂ O is desirably 120 g / l to 200 g / l. When the concentration of CoSO ₄ · 7H ₂ O is less than 120 g / l, the cobalt concentration in the plating solution becomes dilute, and not only industrial productivity is not satisfied, but the smoothness of the plating surface is deteriorated. And even if the concentration of CoSO ₄ · 7H ₂ O exceeds 200 g / l, there is no significant change in the deposition rate of cobalt, but rather the load of waste liquid treatment increases.

Again, like the first composite foil, H ₃ BO ₃ serves as a buffer. The concentration of H ₃ BO ₃ is preferably in the range of 25 g / l to 50 g / l. This H ₃ BO ₃ concentration is determined by the relationship with the above-mentioned concentration of CoSO ₄ .7H ₂ O, and if it is outside this range, the strength of the cobalt layer itself will be insufficient.

The liquid temperature can be in the range of 20 ° C to 50 ° C. In the case of a cobalt plating layer, the tensile strength tends to increase as the liquid temperature decreases. However, when the liquid temperature is less than 20 ° C., the deposition rate of cobalt is lowered, and industrial productivity is not satisfied. On the other hand, when the liquid temperature is around 50 ° C., the tensile strength tends to become a steady value. And when it is set as the solution of the above-mentioned composition, it is possible to obtain a plating film having the best and stable tensile strength by adopting a pH of 2-5. Furthermore, the current density at the time of plating can employ a wide range of 1 A / dm ^{2 to} 50 A / dm ² . This is because the influence of the current density on the tensile strength is small. In particular, considering that the tensile strength of the cobalt plating layer itself is increased, it is desirable to adopt a current density of ^{2 A} / dm ² or less, or a range of 8 A / dm ² or more. The range of ² A / dm ^{2 to} 8 A / dm ² tends to be the lowest tensile strength, but the tensile strength in this current density range does not vary greatly and tends to be a constant level value. Therefore, when importance is attached to ensuring the quality stability of the product, it is preferable to adopt a range of ² A / dm ^{2 to} 8 A / dm ² . The content described above is based on the premise that the stirring bath is used to stir the plating solution.

  It is also preferable to add a flocculant to the cobalt plating solution described above. As the flocculant here, it is possible to use a commercially available flocculant, but it is particularly preferable to use a flocculant containing an acrylamide polymer as a main agent. And this aggregating agent is used to control the deposition rate of cobalt and improve the film thickness uniformity of the plating film so that it becomes 0.05 g / l to 0.3 g / l in the plating bath. It is added. When the flocculant is less than 0.05 g / l, it cannot contribute to the improvement of the film thickness uniformity of the cobalt plating film. The film thickness uniformity starts to deteriorate.

First composite foil (3): Among the first composite foils, the manufacture of the one having a nickel-cobalt plating layer as a dissimilar metal layer on the surface of the copper layer can form a nickel-cobalt plating layer on the surface of the copper foil. If it is a thing, various plating conditions can be employ | adopted. For example, cobalt sulfate 80-180 g / l, nickel sulfate 80-120 g / l, boric acid 20-40 g / l, potassium chloride 10-15 g / l, sodium dihydrogen phosphate 0.1-15 g / l, liquid temperature 30 The conditions are ˜50 ° C., pH 3.5˜4.5, and current density 1˜10 A / dm ² .

  However, in the present invention, it is preferable to employ the nickel-cobalt alloy electroplating bath containing sodium formate in order to obtain a good anti-softening performance of the composite foil. This is because a nickel-cobalt alloy plating layer having the best anti-softening property after high-temperature heating can be obtained. The nickel-cobalt alloy electroplating bath used in the present invention employs a composition in which cobalt sulfate is added to the Watt bath composition during nickel plating. Therefore, a plating solution composition that is extremely simple and enables stable electrolysis is employed.

Here, the NiSO ₄ · 6H ₂ O concentration in the nickel-cobalt alloy electrolytic plating bath is 100 g / l to 200 g / l, the NiCl ₂ · 6H ₂ O concentration is 30 g / l to 50 g / l, and CoSO ₄ · 7H ₂ O. The concentration is desirably in the range of 10 g / l to 30 g / l. In this composition balance range, the nickel-cobalt alloy plating layer having the best anti-softening property after high-temperature heating can be obtained. Therefore, if the range of each component is deviated, a nickel-cobalt alloy plating layer having excellent anti-softening properties after high-temperature heating cannot be obtained.

Again, H ₃ BO ₃ plays a role as a buffering agent, and the concentration of H ₃ BO ₃ is preferably in the range of 20 g / l to 40 g / l. This H ₃ BO ₃ concentration is determined in relation to the above-mentioned concentrations of NiSO ₄ · 6H ₂ O, NiCl ₂ · 6H ₂ O concentration, and CoSO ₄ · 7H ₂ O concentration. The strength of the nickel-cobalt alloy plating layer itself is insufficient, and the film thickness uniformity of the plating layer is also impaired.

The liquid temperature can be in the range of 20 ° C to 50 ° C. Also in the case of a nickel-cobalt alloy plating layer, the tensile strength tends to increase as the liquid temperature decreases. However, when the liquid temperature is less than 20 ° C., the deposition rate of the nickel-cobalt alloy is lowered, and industrial productivity is not satisfied. On the other hand, when the liquid temperature is around 50 ° C., the tensile strength tends to become a steady value. And when it is set as the solution of the above-mentioned composition, it is possible to obtain a plating film having the best and stable tensile strength by adopting a pH of 2-5. Furthermore, the current density at the time of plating can employ a wide range of 1 A / dm ^{2 to} 25 A / dm ² . This is because there is little variation in the content of nickel and cobalt in the nickel-cobalt alloy plating layer, and variation in tensile strength is also minimized. In view of increasing the tensile strength of the nickel-cobalt alloy plating layer itself, it is desirable to employ a current density of 10 A / dm ² or less. The content described above is based on the premise that the stirring bath is used to stir the plating solution.

  And it is also preferable to use sodium formate (HCOONa) for the solution used for forming the nickel-cobalt alloy plating layer in the present invention. This sodium formate is known to be used for obtaining a high hardness by depositing hexavalent chromium ions as trivalent chromium ions and precipitating the chromium plating layer as an amorphous layer. Therefore, when used when forming a nickel-cobalt alloy plating layer as in the present invention, it contributes as a reducing agent for metal ions dissolved in the plating solution, reducing the difference in the precipitation efficiency between the nickel component and the cobalt component, A uniformly dispersed alloy plating layer without uneven distribution of both components can be obtained. Sodium formate is preferably used in a concentration range of 25 g / l to 50 g / l. When the concentration of sodium formate is less than 25 g / l, a uniform mixed state of nickel component and cobalt component in the alloy plating layer cannot be obtained, and even if an amount exceeding 50 g / l concentration is added, A good nickel-cobalt alloy plating layer cannot be obtained.

Second composite foil (1): Among the second composite foils, the one having a cobalt plating layer / hard nickel plating layer as a dissimilar metal layer on the surface of the copper layer is manufactured by using the copper foil as described in A. above. Soaked in a cobalt sulfate electroplating bath having the composition: After the electrolytic plating is performed under the electrolysis conditions of and a cobalt plating layer is formed, the above B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is performed under the electrolytic conditions to form a hard nickel plating layer.

  The contents relating to the cobalt sulfate electrolytic plating solution at this time are the same as the cobalt sulfate electrolytic plating solution of the first composite foil (2). And the content regarding a hard nickel electroplating liquid is the same as that of the hard nickel electroplating liquid of the above-mentioned 1st composite foil (1). Therefore, the description here is omitted to avoid redundant description.

Second composite foil (2): Among the second composite foils, the copper layer surface provided with an iron plating layer / hard nickel plating layer as a dissimilar metal layer is manufactured by using the copper foil as described in A. above. Soaking in an iron sulfate electroplating bath having the composition: After the electrolytic plating is performed under the electrolysis conditions and an iron plating layer is formed, B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is performed under the electrolytic conditions to form a hard nickel plating layer.

  The contents relating to the hard nickel electrolytic plating solution at this time are the same as the hard nickel electrolytic plating solution of the first composite foil (1). Therefore, the description here is omitted to avoid redundant description. Accordingly, only the iron plating solution will be described below.

Here, the concentration of FeSO ₄ .7H ₂ O is desirably 100 g / l to 200 g / l. When the concentration of FeSO ₄ · 7H ₂ O is less than 100 g / l, the iron concentration in the plating solution becomes dilute and the smoothness of the plating surface becomes poor. Even beyond the concentration of 200 g / l of FeSO ₄ · 7H ₂ O, major changes in the deposition rate of the iron is not is rather the load of the waste processing is increased.

Here too, as with the first composite foil, H ₃ BO ₃ is used as a buffering agent. The concentration of H ₃ BO ₃ is desirably in the range of 20 g / l to 50 g / l. This H ₃ BO ₃ concentration is determined by the relationship with the above-mentioned concentration of FeSO ₄ .7H ₂ O, and if it is outside this range, it tends to be a brittle iron plating layer.

The liquid temperature can be in the range of 20 ° C to 50 ° C. When the liquid temperature is less than 20 ° C., the deposition rate of iron is lowered, and industrial productivity is not satisfied. On the other hand, when the liquid temperature exceeds 50 ° C., the solution life is shortened and the management cost is increased. And when it is set as the solution of the above-mentioned composition, it is possible to obtain a plating film having the best and stable tensile strength by adopting a pH of 2-5. Furthermore, the current density at the time of plating can employ a range of 1 A / dm ^{2 to} 30 A / dm ² . This is because the influence of the current density on the tensile strength is small. In particular, considering that both the toughness and tensile strength of the iron plating layer itself are increased, it is desirable to adopt a current density of ^{2 A} / dm ² or less, or a range of 8 A / dm ² or more. The range of ² A / dm ^{2 to} 8 A / dm ² tends to be the lowest tensile strength, but the tensile strength in this current density range does not vary greatly and tends to be a constant level value. Therefore, when importance is attached to ensuring the quality stability of the product, it is preferable to adopt a range of ² A / dm ^{2 to} 8 A / dm ² . The content described above is based on the premise that the stirring bath is used to stir the plating solution.

  It is preferable to add an aggregating agent to the iron plating solution described above. As the flocculant here, it is possible to use a commercially available flocculant, but it is particularly preferable to use a flocculant containing an acrylamide polymer as a main agent. And this aggregating agent is used to control the deposition rate of iron and improve the film thickness uniformity of the plating film, so that it becomes 0.05 g / l to 0.3 g / l in the plating bath. It is added. When the flocculant is less than 0.05 g / l, it cannot contribute to the improvement of the film thickness uniformity of the iron plating film. The film thickness uniformity of the coating or iron plating coating begins to deteriorate.

Third composite foil (1): Among the third composite foils, the copper layer surface is provided with a first cobalt plating layer / hard nickel plating layer / second cobalt plating layer as a dissimilar metal layer. A. above. Soaked in a cobalt sulfate electroplating bath having the composition: After the electrolytic plating is performed under the electrolytic conditions of (1) to form the first cobalt plating layer, the above B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is carried out under the electrolysis conditions to form a hard nickel plating layer. Soaked in a cobalt sulfate electroplating bath having the composition: The second cobalt plating layer is formed by electrolytic plating under the electrolytic conditions of

  The contents relating to the cobalt sulfate electrolytic plating solution at this time are the same as the cobalt sulfate electrolytic plating solution of the first composite foil (2). And the content regarding a hard nickel electroplating liquid is the same as that of the hard nickel electroplating liquid of the above-mentioned 1st composite foil (1). Therefore, the description here is omitted to avoid redundant description.

Third composite foil (2): Among the third composite foils, the production of the copper composite layer having an iron plating layer / hard nickel plating layer / cobalt plating layer as a different metal layer on the surface of the copper layer is carried out using Soaking in an iron sulfate electroplating bath having the composition: After the electrolytic plating is performed under the electrolysis conditions and an iron plating layer is formed, B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is performed under the electrolytic conditions to form a hard nickel plating layer. Soaked in a cobalt sulfate electroplating bath having the composition: Electrolytic plating is performed under the electrolysis conditions to form a cobalt plating layer

  The contents relating to the iron sulfate electroplating solution at this time are the same as the iron sulfate electroplating solution of the second composite foil (2). And the content regarding a hard nickel electroplating liquid is the same as that of the hard nickel electroplating liquid of the above-mentioned 1st composite foil (1). Further, the contents relating to the cobalt sulfate electrolytic plating solution are the same as the cobalt sulfate electrolytic plating solution of the first composite foil (2). Therefore, the description here is omitted to avoid redundant description.

<Manufacturing form of capacitor layer forming material according to the present invention>
As a method of forming a capacitor layer forming material using the above composite foil, a dielectric layer is formed on the surface of the composite foil provided with the different metal layer. There is no particular limitation on the material of the dielectric layer. The dielectric layer is also formed by a so-called sol-gel method, a coating method for forming a dielectric layer by coating using a dielectric filler-containing resin solution containing a dielectric filler and a binder resin, and containing a dielectric filler. Various known methods such as a method of laminating the prepared film can be employed. When the formation of the dielectric layer is completed, the first conductive layer for forming the upper electrode is provided on the dielectric layer. For the formation of the first conductive layer on the dielectric layer, various methods such as a method of bonding using a metal foil, a method of forming a conductive layer by plating, a method of using a method such as sputtering deposition, etc. can be adopted. It is.

<Manufacturing Form of Printed Wiring Board with Built-in Capacitor Circuit Obtained Using Capacitor Layer Forming Material According to Present Invention>
By using the capacitor layer forming material according to the present invention described above, it becomes possible to form a lower electrode with excellent adhesion to the dielectric layer, and the lower electrode is a material with excellent heat resistance. Even when hot pressing in the range of 300 ° C. to 400 ° C. is performed a plurality of times, oxidation deterioration does not occur and physical property changes hardly occur. There is no particular limitation on the method of manufacturing a printed wiring board having a built-in capacitor circuit using the capacitor layer forming material according to the present invention, and any method can be adopted. However, as shown in the following embodiments, it is preferable to employ a method for manufacturing a printed wiring board that can remove as much as possible an extra dielectric layer other than the portion where the capacitor circuit is formed.

  In this embodiment, a first composite foil having a hard nickel plating layer is manufactured, a capacitor layer forming material is manufactured using the first composite foil, and a printed wiring board having a built-in capacitor circuit is manufactured. went.

<Manufacture of first composite foil>
Here, electrolytic copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Mining & Smelting Co., Ltd.) is immersed in a hard nickel electrolytic plating bath having the following composition, electroplated under the following electrolytic conditions, and the electrolytic copper foil is thick on the glossy surface. A hard nickel plating layer corresponding to a thickness of 2 μm and a thickness of 3 μm was formed on the rough surface to prepare a first composite foil having a thickness of 17.5 μm. The thickness of the dissimilar metal layer referred to in this specification is a thickness based on the basis weight when an attempt is made to form a dissimilar metal layer having a predetermined thickness by a plating method on a flat surface. The thickness of the produced composite foil is shown as a gauge thickness. The same applies to the following examples and comparative examples.

(Hard nickel electroplating bath composition)
_{NiSO 4 · 6H 2 O 162g /} l
NH ₄ Cl 25 g / l
H ₃ BO ₃ 30 g / l
(Plating conditions)
Bath temperature 35 ℃
pH 4
Current density 10A / dm ²
There is stirring

  About the obtained 1st composite foil, the tensile strength and elongation rate after heating at 400 degreeC x 10 hours in a normal state and vacuum were evaluated. The results are shown in Table 1. In addition, the measurement of tensile strength and elongation rate was performed based on the measurement of the copper foil for printed wiring boards defined in IPC-TM-650 defined in IPC-MF-150F. The same applies hereinafter.

<Manufacture of capacitor layer forming material>
The first composite foil is used for forming the second conductive layer used for forming the lower electrode of the capacitor layer forming material, and a sol-gel method is applied to the surface of the hard nickel plating layer existing on the outer layer of the first composite foil. Was used to form a dielectric layer.

  In the sol-gel method used here, ethanolamine was added to a methanol solution heated near the boiling point as a stabilizer so as to have a concentration of 50 mol% to 60 mol% with respect to the total amount of metal, and titanium isopropoxide. Then, a propanol solution of zirconium propoxide, lead acetate, lanthanum acetate, and nitric acid as a catalyst were sequentially added, and finally a sol-gel solution diluted with methanol to a concentration of 0.2 mol / l was used. Then, this sol-gel solution was applied to the surface of the hard nickel plating layer of the surface-treated copper foil using a spin coater, dried in an air atmosphere at 250 ° C. × 5 minutes, and air atmosphere at 500 ° C. × 15 minutes. Pyrolysis is performed. Further, the coating process was repeated 6 times to adjust the film thickness. Finally, a baking process was performed in a nitrogen substitution atmosphere at 600 ° C. for 30 minutes to form a dielectric layer. The composition ratio of the dielectric layer at this time was Pb: La: Zr: Ti = 1.1: 0.05: 0.52: 0.48, and no abnormality was observed in the composite foil itself.

  On the dielectric layer formed as described above, a copper layer having a thickness of 3 μm is formed as a first conductive layer by a sputtering vapor deposition method, and the capacitor includes the first conductive layer and the second conductive layer on both sides of the dielectric layer. A layer forming material was obtained. At this stage, a predetermined voltage was applied and interlayer withstand voltage measurement was performed, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer.

<Manufacture of printed wiring boards>
Hereinafter, manufacture of a printed wiring board will be described with reference to FIGS. 11 to 14. In these drawings, a case in which the capacitor layer constituting material 1b ′ shown in FIG. 3B is used is shown as a model. . Therefore, it should be noted that the layer structure of the capacitor layer constituent material differs depending on each embodiment. Hereinafter, manufacture of a printed wiring board will be described.

  The first conductive layer 2 on one side of the capacitor layer forming material 1a shown in FIG. 11 (a) manufactured as described above was leveled, and a dry film was laminated on both sides to form an etching resist layer 21. Then, an etching pattern for forming the upper electrode was exposed and developed on the etching resist layer on the surface of the first conductive layer. And it etched with the copper chloride etching liquid, and as shown in FIG.11 (b), the upper electrode 15 was formed.

  Then, with the etching resist remaining on the circuit surface after the formation of the upper electrode 15, the exposed dielectric layer in the region other than the circuit portion was removed. The method for removing the dielectric layer at this time uses wet blasting, and a slurry-like polishing liquid (abrasive concentration 14 vol%) in which an alumina abrasive, which is a fine powder having a center particle diameter of 14 μm, is dispersed in water, An unnecessary dielectric layer was polished and removed by impinging on the surface to be polished as a high-speed water flow from a slit nozzle having a length of 90 mm and a width of 2 mm at a water pressure of 0.20 MPa. When this wet blasting process is completed, the etching resist is peeled off, washed with water, and dried to obtain the state shown in FIG.

  In the capacitor layer forming material after the removal of the dielectric layer, it is necessary to remove the exposed dielectric layer and bury a deeper gap between the upper electrodes. Therefore, as shown in FIG. 12D, in order to provide the insulating layer and the conductive layer on both surfaces of the capacitor layer forming material, the copper with resin layer provided with the semi-cured resin layer 7 having a thickness of 80 μm on one surface of the copper foil 10. The foil 8 was overlapped and hot press-molded under a heating condition of 180 ° C. × 60 minutes, and the state shown in FIG. 12E was obtained, in which the copper foil layer 10 and the insulating layer 7 ′ were bonded to the outer layer. Then, the outer second conductive layer 4 shown in FIG. 12 (e) was etched to form the lower electrode 9, which was in the state shown in FIG. 12 (f).

  Next, in order to form the outer layer circuit 22 and the via hole 23 in the copper foil layer 10 located in the outer layer, the copper plating layer 24 was provided based on a conventional method, and the etching process was performed to obtain the state shown in FIG. And as shown in FIG.13 (h), the copper foil 8 with a resin layer is piled up, it hot-press-molds on the heating conditions of 180 degreeC x 60 minutes, and copper foil layer 10 and insulating layer 7 'are carried out to an outer layer. And the state shown in FIG. 14 (i).

  Then, in order to form the outer layer circuit 22 and the via hole 23 in the outer copper foil layer 10 shown in FIG. 14 (i), a copper plating layer 24 is provided according to a conventional method and etched to obtain the state of FIG. 14 (j). A printed wiring board 30 having a built-in capacitor circuit was manufactured.

  In this example, a first composite foil including a cobalt layer was manufactured, a capacitor layer forming material was manufactured using the first composite foil, and a printed wiring board including a built-in capacitor circuit was manufactured. .

<Manufacture of first composite foil>
Here, electrolytic copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Mining & Smelting Co., Ltd.) is immersed in a cobalt electrolytic plating bath having the following composition, electroplated under the following electrolytic conditions, and the thickness of the electrolytic copper foil is increased on the glossy surface. A cobalt plating layer having a thickness of 2 μm and a thickness of 3 μm was formed on the rough surface to prepare a first composite foil having a thickness of 17.8 μm.

(Cobalt electroplating bath composition)
_{CoSO 4 · 7H 2 O 180g /} l
H ₃ BO ₃ 30 g / l
Flocculant 0.1g / l
(Acrylamide polymer, trade name: PN-171, manufactured by Kurita Kogyo Co., Ltd.)
(Plating conditions)
Bath temperature 35 ℃
pH 4
Current density 10A / dm ²
There is stirring

  And about the obtained 2nd composite foil, the tensile strength and elongation rate after heating in a normal state and 400 degreeC x 10 hours in a vacuum were evaluated like Example 1. The results are shown in Table 1.

Thereafter, in the same manner as in Example 1, a printed wiring board including a capacitor layer forming material and a built-in capacitor circuit was manufactured. The capacitor layer forming material obtained here was loaded with a predetermined voltage and subjected to interlayer withstand voltage measurement, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer. Also, printed wiring boards with built-in capacitor circuits could be manufactured without any problems.

  In this embodiment, a first composite foil including a nickel-cobalt alloy layer is manufactured, a capacitor layer forming material is manufactured using the first composite foil, and a printed wiring board including a built-in capacitor circuit is manufactured. Went.

<Manufacture of first composite foil>
Here, electrolytic copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Kinzoku Mining Co., Ltd.) is dipped in a nickel-cobalt alloy electrolytic plating bath having the following composition, electroplated under the following electrolytic conditions, and the glossy surface of the electrolytic copper foil A nickel-cobalt alloy plating layer having a thickness of 2 μm and a thickness of 3 μm was formed on the rough surface to prepare a first composite foil having a thickness of 17.2 μm.

(Nickel-cobalt electroplating bath composition)
_{NiSO 4 · 6H 2 O 200g /} l
NiCl ₂ · 6H ₂ O 36 g / l
_{CoSO 4 · 7H 2 O 12g /} l
H ₃ BO ₃ 30 g / l
HCOONa 45g / l
(Plating conditions)
Bath temperature 45 ° C
pH 4
Current density 10A / dm ²
There is stirring

  Then, as in Example 1, the normal state of the obtained third composite foil and the tensile strength and elongation after heating in a vacuum at 400 ° C. for 10 hours were evaluated. The results are shown in Table 1.

Thereafter, in the same manner as in Example 1, a printed wiring board including a capacitor layer forming material and a built-in capacitor circuit was manufactured. The capacitor layer forming material obtained here was loaded with a predetermined voltage and subjected to interlayer withstand voltage measurement, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer. Also, printed wiring boards with built-in capacitor circuits could be manufactured without any problems.

  Here, a second composite foil in which a cobalt plating layer and a hard nickel plating layer are sequentially formed using an electrolytic copper foil is manufactured, and a capacitor layer forming material is manufactured using the second composite foil. Furthermore, a printed wiring board provided with a built-in capacitor circuit was manufactured.

<Manufacture of second composite foil>
Electrolytic copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Mining & Smelting Co., Ltd.) is immersed in the same cobalt electrolytic plating bath as in Example 2, and electrolytic plating is performed in the same manner as in Example 2. A cobalt plating layer corresponding to a thickness of 0.3 μm is formed on each rough surface, and then immersed in a hard nickel electroplating bath similar to that in Example 1, followed by electrolytic plating in the same manner as in Example 1, Then, a hard nickel plating layer corresponding to a thickness of 2 μm on the glossy surface side and a thickness of 3 μm on the rough surface side of the copper foil was formed to prepare a composite foil having a thickness of 16.9 μm.

  Then, as in Example 1, the normal state of the obtained second composite foil and the tensile strength and elongation after heating in a vacuum at 400 ° C. for 10 hours were evaluated. The results are shown in Table 1.

Thereafter, in the same manner as in Example 1, a printed wiring board including a capacitor layer forming material and a built-in capacitor circuit was manufactured. The capacitor layer forming material obtained here was loaded with a predetermined voltage and subjected to interlayer withstand voltage measurement, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer. Also, printed wiring boards with built-in capacitor circuits could be manufactured without any problems.

  Here, a second composite foil in which an iron plating layer and a hard nickel plating layer are sequentially formed using an electrolytic copper foil is manufactured, and a capacitor layer forming material is manufactured using the second composite foil. Furthermore, a printed wiring board provided with a built-in capacitor circuit was manufactured.

<Manufacture of second composite foil>
Electrolytic copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Kinzoku Mining Co., Ltd.) is immersed in a sulfate iron electrolytic plating bath having the following composition, and electrolytic plating is performed under the following conditions. An iron plating layer corresponding to a thickness of 0.3 μm is formed, and then immersed in a hard nickel electrolytic plating bath similar to that in Example 1, and electrolytic plating is performed in the same manner as in Example 1, and a copper plating layer is formed on the cobalt plating layer. A hard nickel plating layer having a thickness of 2 μm was formed on the glossy surface side of the foil and a thickness of 3 μm was formed on the rough surface side to prepare a composite foil having a thickness of 17.4 μm.

(Sulfate iron electroplating bath composition)
_{FeSO 4 · 7H 2 O 180g /} l
H ₃ BO ₃ 30 g / l
(Plating conditions)
Bath temperature 30 ° C
pH 4
Current density 5A / dm ²
There is stirring

  Then, as in Example 1, the normal state of the obtained second composite foil and the tensile strength and elongation after heating in a vacuum at 400 ° C. for 10 hours were evaluated. The results are shown in Table 1.

Thereafter, in the same manner as in Example 1, a printed wiring board including a capacitor layer forming material and a built-in capacitor circuit was manufactured. The capacitor layer forming material obtained here was loaded with a predetermined voltage and subjected to interlayer withstand voltage measurement, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer. Also, printed wiring boards with built-in capacitor circuits could be manufactured without any problems.

  In this embodiment, a third composite foil having a first cobalt plating layer / hard nickel plating layer / second cobalt plating layer on the copper foil surface is manufactured, and a capacitor layer forming material is manufactured using the third composite foil. In addition, a printed wiring board having a built-in capacitor circuit was manufactured.

<Manufacture of third composite foil>
Using copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Mining & Mining Co., Ltd.), the electrolytic copper foil is immersed in the cobalt sulfate electrolytic plating bath of Example 2 on the glossy and rough surfaces of the electrolytic copper foil, and the electrolysis conditions of Example 2 Then, electrolytic plating was performed to form a first cobalt plating layer corresponding to a thickness of 0.3 μm on both surfaces. And it immersed in the hard nickel electroplating bath of the composition of Example 1, and electroplated on the electrolysis conditions of Example 1, and formed the hard nickel plating layer equivalent to 3 micrometers thickness on both surfaces. Furthermore, it was immersed in the cobalt sulfate electroplating bath of Example 2, and electroplated under the electrolysis conditions of Example 2 to form a second cobalt plating layer corresponding to a thickness of 0.3 μm. Three composite foils were produced.

  Then, as in Example 1, the normal state of the obtained third composite foil and the tensile strength and elongation after heating in a vacuum at 400 ° C. for 10 hours were evaluated. The results are shown in Table 1.

Thereafter, in the same manner as in Example 1, a printed wiring board including a capacitor layer forming material and a built-in capacitor circuit was manufactured. The capacitor layer forming material obtained here was loaded with a predetermined voltage and subjected to interlayer withstand voltage measurement, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer. Also, printed wiring boards with built-in capacitor circuits could be manufactured without any problems.

  In this embodiment, a third composite foil having an iron plating layer / hard nickel plating layer / cobalt plating layer on the copper foil surface is manufactured, and a capacitor layer forming material is manufactured using the third composite foil. A printed wiring board with a built-in capacitor circuit was manufactured.

  The copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Mining & Mining Co., Ltd.) is used to immerse the electrolytic copper foil in the glossy and rough surfaces in the iron sulfate electrolytic plating bath of Example 5, and the electrolysis conditions of Example 5 Then, an iron plating layer having a thickness of 0.3 μm was formed on both sides. And it immersed in the hard nickel electroplating bath of the composition of Example 1, and electroplated on the electrolysis conditions of Example 1, and formed the hard nickel plating layer equivalent to 3 micrometers thickness on both surfaces. Further, it is immersed in the cobalt sulfate electroplating bath of Example 2, and electroplated under the electrolysis conditions of Example 2 to form a second cobalt plating layer corresponding to a thickness of 0.3 μm, and a 19.3 μm thick first layer is formed. Three composite foils were produced.

  Then, as in Example 1, the normal state of the obtained third composite foil and the tensile strength and elongation after heating in a vacuum at 400 ° C. for 10 hours were evaluated. The results are shown in Table 1.

Thereafter, in the same manner as in Example 1, a printed wiring board including a capacitor layer forming material and a built-in capacitor circuit was manufactured. The capacitor layer forming material obtained here was loaded with a predetermined voltage and subjected to interlayer withstand voltage measurement, but no short-circuit phenomenon was observed between the first conductive layer and the second conductive layer. Also, printed wiring boards with built-in capacitor circuits could be manufactured without any problems.

Comparative example

[Comparative Example 1]
Without forming a hard nickel plating layer on the electrolytic copper foil of Example 1 (thickness 12 μm, VLP foil, manufactured by Mitsui Mining & Smelting Co., Ltd.), this electrolytic copper foil was used to produce a capacitor layer forming material. An attempt was made to produce a printed wiring board with a built-in capacitor circuit.

  However, when a method similar to that in Example 1 was employed to form a dielectric layer using a sol-gel method on the outer layer surface of the electrolytic copper foil in an attempt to produce a capacitor layer forming material, Oxidation on the surface of the electrolytic copper foil was noticeable by thermal decomposition in an air atmosphere for 15 minutes. Further, when this coating process is repeated 6 times and the film thickness is adjusted, the surface of the electrolytic copper foil further oxidizes, and finally the embrittlement due to oxidation is caused by the baking treatment in a nitrogen substitution atmosphere at 600 ° C. for 30 minutes. The electrolytic copper foil was easily cracked. Therefore, all of the following steps cannot be performed, and the capacitor layer forming material and the printed wiring board cannot be manufactured.

[Comparative Example 2]
This comparative example is different only in that the hard nickel plating layer of the composite foil constituting the second conductive layer of Example 1 is a nickel-phosphorus alloy plating layer. Therefore, the description of the duplicated description is omitted as much as possible.

  Here, electrolytic copper foil (thickness 12 μm, VLP foil, manufactured by Mitsui Kinzoku Mining Co., Ltd.) is immersed in a nickel-phosphorous electrolytic plating bath having the following composition, and electrolytic plating is performed under the following electrolysis conditions to provide a glossy surface for the electrolytic copper foil. A nickel-phosphorus alloy plating layer having a thickness of 2 μm and a thickness of 3 μm was formed on the rough surface (phosphorus content was 0.3 wt%) to prepare a first composite foil having a thickness of 17 μm.

The nickel-phosphorus alloy layer uses a phosphate-based solution, the nickel sulfate concentration is 250 g / l, the nickel chloride concentration is 40.39 g / l, the H ₃ BO ₃ concentration is 19.78 g / l, and the H ₃ PO ₃ concentration is 3 g / l. Electrolysis was performed under the conditions of a liquid temperature of 50 ° C. and a current density of 20 A / dm ² , and a nickel-phosphorus alloy layer was deposited uniformly and smoothly on both surfaces of the electrolytic copper foil.

  Then, the capacitor layer forming material including the first conductive layer and the second conductive layer on both sides of the dielectric layer after manufacturing the capacitor layer forming material by forming the dielectric layer by the sol-gel method as in the first embodiment. It was. The interlayer withstand voltage was measured at this stage, but a short phenomenon occurred between the first conductive layer and the second conductive layer, and the product yield was 60%.

  Since the capacitor layer forming material according to the present invention includes the composite foil having excellent high-temperature heat resistance in the second conductive layer constituting the lower electrode, the multilayer printed wiring board using the fluororesin substrate and the liquid crystal polymer substrate is used. Suitable for manufacturing. Even if hot pressing in the range of 300 ° C. to 400 ° C. used for manufacturing printed wiring boards using these substrates is repeated, no abnormality occurs in the shape of the lower electrode even after the capacitor circuit shape is formed. Resistant to the expansion and contraction behavior of the surrounding material due to heat. In addition, since it has such excellent heat resistance characteristics, there is no problem even if it receives a severe heat history when forming a dielectric layer on the surface of the composite foil by a sol-gel method.

  In addition, since the combination of the dissimilar metal layer and the layer configuration of the composite foil used for forming the second conductive layer of the capacitor layer forming material according to the present invention can be appropriately selected according to the type of the dielectric layer, Good adhesion between the layer and the lower electrode can be maintained. As a result, the quality of the printed wiring board provided with the built-in capacitor circuit obtained using the capacitor layer forming material according to the present invention is also improved. Further, since the dissimilar metal layer is a high resistance metal such as nickel, it can be used for forming a resistor circuit.

  Furthermore, the manufacturing method of the composite foil used for manufacturing the capacitor layer forming material according to the present invention employs a constant plating condition for the dissimilar metal layer, so that the metal foil for the capacitor layer forming material having excellent heat resistance is inexpensive. Can be manufactured.

It is a schematic cross section of the capacitor layer forming material according to the present invention. It is a schematic cross section of the composite foil used for manufacture of the capacitor layer forming material which concerns on this invention. It is a schematic cross section of the capacitor layer forming material according to the present invention. It is a schematic cross section of the composite foil used for manufacture of the capacitor layer forming material which concerns on this invention. 2 is a normal optical micrograph of a composite foil in which a cobalt plating layer and a hard nickel plating layer are sequentially laminated on the surface of a copper foil. It is an optical microscope photograph after the heating (400 degreeC x 10 hours) of the composite foil by which the cobalt plating layer and the hard nickel plating layer were laminated | stacked sequentially on the surface of copper foil. It is a normal optical microscope photograph of the composite foil provided with the hard nickel plating layer on the surface of the copper foil. It is an optical microscope photograph after the heating (400 degreeC x 10 hours) of the composite foil provided with the hard nickel plating layer on the surface of copper foil. It is a schematic cross section of the capacitor layer forming material according to the present invention. It is a schematic cross section of the composite foil used for manufacture of the capacitor layer forming material which concerns on this invention. It is a schematic diagram showing the manufacturing flow of a printed wiring board provided with the built-in capacitor circuit using the capacitor layer forming material which concerns on this invention. It is a schematic diagram showing the manufacturing flow of a printed wiring board provided with the built-in capacitor circuit using the capacitor layer forming material which concerns on this invention. It is a schematic diagram showing the manufacturing flow of a printed wiring board provided with the built-in capacitor circuit using the capacitor layer forming material which concerns on this invention. It is a schematic diagram showing the manufacturing flow of a printed wiring board provided with the built-in capacitor circuit using the capacitor layer forming material which concerns on this invention.

Explanation of symbols

1a, 1b, 1c, 1a ′, 1b ′, 1c ′ Capacitor layer forming material 5a, 5b, 5c, 5a ′, 5b ′, 5c ′ Composite foils 6a, 6b, 6c Dissimilar metal layer 2 First conductive layer
3 Dielectric layer 4 Second conductive layer 7 Semi-cured resin layer 7 ′ Insulating layer 8 Copper foil 9 with resin Lower electrode 10 Copper foil layer 15 Upper electrode 21 Etching resist layer 22 Outer circuit 23 Via hole 24 Copper plating layer 30 Printed wiring board C Copper layer

Claims (28)

In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
A capacitor layer forming material, wherein the second conductive layer is a composite foil having a hard nickel plating layer which is a different metal layer on the surface of a copper layer. The capacitor layer forming material according to claim 1, wherein the hard nickel plating layer has a thickness of 0.5 μm to 3.0 μm. In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
A capacitor layer forming material, wherein the second conductive layer is a composite foil having a cobalt plating layer which is a different metal layer on the surface of a copper layer. The capacitor layer forming material according to claim 3, wherein the cobalt plating layer has a thickness of 0.5 μm to 3.0 μm. In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
The second conductive layer is a capacitor layer forming material using a composite foil having a nickel-cobalt alloy plating layer which is a different metal layer on the surface of a copper layer. The material for forming a capacitor layer according to claim 5, wherein the nickel-cobalt alloy plating layer has a thickness of 0.5 μm to 3.0 μm. In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
A capacitor layer forming material, wherein the second conductive layer is a composite foil comprising two dissimilar metal layers in which a cobalt plating layer / hard nickel plating layer are sequentially laminated on the surface of a copper layer. The material for forming a capacitor layer according to claim 7, wherein the cobalt plating layer has a thickness of 0.1 µm to 0.5 µm, and the hard nickel plating layer has a thickness of 0.3 µm to 2.0 µm. In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
A capacitor layer forming material, wherein the second conductive layer is a composite foil comprising two dissimilar metal layers in which an iron plating layer / hard nickel plating layer are sequentially laminated on the surface of a copper layer. The material for forming a capacitor layer according to claim 9, wherein the iron plating layer has a thickness of 0.1 μm to 0.5 μm, and the hard nickel plating layer has a thickness of 0.3 μm to 2.0 μm. In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
The second conductive layer is made of a composite foil having three different metal layers laminated in order of the first cobalt plating layer / hard nickel plating layer / second cobalt plating layer on the surface of the copper layer. Capacitor layer forming material. The thickness of the first cobalt plating layer is 0.1 μm to 0.5 μm, the thickness of the hard nickel plating layer is 0.3 μm to 2.0 μm, and the thickness of the second cobalt plating layer is 0.1 μm to 0.5 μm. The material for forming a capacitor layer according to claim 11. In the capacitor layer forming material of the printed wiring board comprising a dielectric layer between the first conductive layer used for forming the upper electrode and the second conductive layer used for forming the lower electrode,
The second conductive layer is a capacitor layer forming material comprising a composite foil having three different metal layers laminated in order of an iron plating layer / hard nickel plating layer / cobalt plating layer on the surface of a copper layer . The thickness of the iron plating layer is 0.1 μm to 0.5 μm, the thickness of the hard nickel plating layer is 0.3 μm to 2.0 μm, and the thickness of the cobalt plating layer is 0.1 μm to 0.5 μm. The capacitor layer forming material as described. The said copper layer uses electrolytic copper foil or rolled copper foil, and the nominal thickness of the said copper foil is 9 micrometers-35 micrometers, The material for capacitor layer formation in any one of Claims 1-14 . A method for producing a composite foil comprising a hard nickel plating layer as a different metal layer on the surface of a copper layer used for the second conductive layer of the capacitor layer forming material according to the present invention,
A method for producing a composite foil, comprising immersing a copper foil in a hard nickel electrolytic plating bath having the following composition and performing electrolytic plating under the following electrolysis conditions to form a hard nickel plating layer.
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 3-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring A method for producing a composite foil comprising a cobalt plating layer as a dissimilar metal layer on the surface of a copper layer used for the second conductive layer of the capacitor layer forming material according to the present invention,
A method for producing a composite foil, comprising immersing a copper foil in a cobalt sulfate electrolytic plating bath having the following composition, and performing electrolytic plating under the following electrolytic conditions to form a cobalt plating layer.
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring The method for producing a composite foil according to claim 17, wherein the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l. A method for producing a composite foil comprising a nickel-cobalt alloy plating layer as a dissimilar metal layer on the surface of a copper layer used for the second conductive layer of the capacitor layer forming material according to the present invention,
A method for producing a composite foil, comprising immersing a copper foil in a nickel-cobalt alloy electroplating bath having the following composition, and performing electroplating under the following electrolysis conditions to form a nickel-cobalt alloy plating layer.
_{NiSO 4 · 6H 2 O 100g /} l~200g / l
NiCl ₂ · 6H ₂ O 30 g / l to 50 g / l
CoSO ₄ · 7H ₂ O 10 g / l to 30 g / l
H ₃ BO ₃ 20 g / l to 40 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 25 A / dm ²
There is stirring A method for producing a composite foil comprising a cobalt plating layer / hard nickel plating layer as a different metal layer on the surface of a copper layer used for the second conductive layer of the capacitor layer forming material according to the present invention,
The copper foil was bonded to the following A. And immersed in a cobalt sulfate electrolytic plating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions, and the cobalt plating layer is formed, the following B. A hard nickel electrolytic plating bath having the composition of A method for producing a composite foil, characterized in that a hard nickel plating layer is formed by electrolytic plating under the electrolysis conditions of:
[A. Composition, electrolysis conditions]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring The method for producing a composite foil according to claim 20, wherein the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l. A method for producing a composite foil comprising an iron plating layer / hard nickel plating layer as a dissimilar metal layer on the surface of the copper layer used for the second conductive layer of the capacitor layer forming material according to the present invention,
The copper foil was bonded to the following A. And immersed in an iron sulfate electroplating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions, and the iron plating layer is formed, the following B. A hard nickel electrolytic plating bath having the composition of A method for producing a composite foil, characterized in that a hard nickel plating layer is formed by electrolytic plating under the electrolysis conditions of:
[A. Composition, electrolysis conditions]
FeSO ₄ · 7H ₂ O 100 g / l to 200 g / l
H ₃ BO ₃ 20 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 30 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring The method for producing a composite foil according to claim 22, wherein the iron sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l. A method for producing a composite foil comprising a first cobalt plating layer / hard nickel plating layer / second cobalt plating layer as a dissimilar metal layer on a copper layer surface used for a second conductive layer of a capacitor layer forming material according to the present invention,
The copper foil was bonded to the following A. And immersed in a cobalt sulfate electrolytic plating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions of (1) to form the first cobalt plating layer, the following B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is performed under the electrolytic conditions to form a hard nickel plating layer. And immersed in a cobalt sulfate electrolytic plating bath having the following composition: A method for producing a composite foil, wherein the second cobalt plating layer is formed by performing electrolytic plating under the electrolysis conditions of:
[A. Composition, electrolysis conditions]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring The method for producing a composite foil according to claim 24, wherein the cobalt sulfate electrolytic plating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l. A method for producing a composite foil comprising an iron plating layer / hard nickel plating layer / cobalt plating layer as a dissimilar metal layer on the copper layer surface used for the second conductive layer of the capacitor layer forming material according to the present invention,
The copper foil was bonded to the following A. And immersed in an iron sulfate electroplating bath having the following composition: After the electrolytic plating is performed under the electrolytic conditions, and the iron plating layer is formed, the following B. A hard nickel electrolytic plating bath having the composition of Electrolytic plating is performed under the electrolysis conditions to form a hard nickel plating layer. The following C.I. A method for producing a composite foil, characterized in that a cobalt plating layer is formed by performing electroplating under the electrolysis conditions of:
[A. Composition, electrolysis conditions]
FeSO ₄ · 7H ₂ O 100 g / l to 200 g / l
H ₃ BO ₃ 20 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 30 A / dm ²
Stirring [B. Composition, electrolysis conditions]
_{NiSO 4 · 6H 2 O 100g /} l~180g / l
NH ₄ Cl concentration 20 g / l to 30 g / l
H ₃ BO ₃ concentration 20 g / l to 60 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 4-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
With stirring [C. Composition, electrolysis conditions]
CoSO ₄ · 7H ₂ O 120 g / l to 200 g / l
H ₃ BO ₃ 25 g / l to 50 g / l
Liquid temperature 20 ℃ ~ 50 ℃
pH 2-5
Current density 1 A / dm ^{2 to} 50 A / dm ²
There is stirring 27. The method of manufacturing a composite foil according to claim 26, wherein the cobalt sulfate electroplating bath contains a flocculant at a concentration of 0.05 g / l to 0.3 g / l. A printed wiring board provided with the built-in capacitor circuit obtained using the capacitor layer forming material in any one of Claims 1-15.