JP2007242767A - Circuit board including built-in solid electrolytic capacitor, method for manufacturing the same, and interposer including built-in solid electrolytic capacitor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor including arrangement of a capacitor for removing power supply noise and being reinforced in GND, in order to solve a problem that a wiring area using GND becomes small through further improvement in micro-miniaturization of wiring, and sufficient GND cannot be acquired to become a noise source. <P>SOLUTION: The circuit board includes a built-in solid electrolytic capacitor element provided with a valve metal sheet body 102, a dielectric material oxide film layer 104 provided to a single surface of this valve metal sheet body 102, a solid electrolytic layer 105 provided on the dielectric material oxide film layer 104, and a capacitance forming part formed of current collector 106 for cathode provided on the solid electrolytic layer 105. In the circuit board, the current collector 106 for cathode is electrically connected with the metal sheet body 102 and this metal sheet body 102 is arranged almost in the same plane as the solid electrolytic capacitor element. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sheet capacitor used in various electronic devices.

Noise countermeasures are required as equipment increases in speed and frequency. When the semiconductor mounted on the surface of the interposer is switched at a high frequency, noise in the power supply system leaks to the outside. This affects the IC chip mounted on the surface of the wiring board, or another IC board mounted on the motherboard on which the wiring board itself is mounted, or affects the IC chip built in the same board, and malfunctions. May be incurred. Until now, proposals have been made to incorporate a solid electrolytic capacitor inside a substrate (see, for example, Patent Document 1).
JP 2004-221534 A

  On the other hand, in an interposer that requires a substrate with a built-in solid electrolytic capacitor, the wiring of the substrate is becoming finer. As the fineness of the wiring advances, the wiring area that can be used for GND becomes smaller, and the GND cannot be secured sufficiently. For this reason, a potential difference is generated in the GND of the capacitor, which becomes a noise source. Accordingly, an object of the present invention is to realize a solid electrolytic capacitor in which capacitors used for removing power supply noise are arranged and GND is reinforced.

A valve metal sheet body;
A dielectric oxide film layer provided on the surface of the valve metal sheet body;
A solid electrolyte layer provided on the dielectric oxide film layer;
Built-in solid electrolytic capacitor element having a capacitance forming portion composed of a cathode current collector provided on the solid electrolyte layer,
A metal sheet body electrically connected to the cathode current collector;
The circuit board with a built-in solid electrolytic capacitor, wherein the metal sheet body is arranged in substantially the same plane as the solid electrolytic capacitor element.

  By using the circuit board with a built-in solid electrolytic capacitor of the present invention, sufficient GND can be secured for the solid electrolytic capacitor, and stable noise removal is possible.

(Embodiment 1)
Hereinafter, a solid electrolytic capacitor built-in circuit board, a method of forming the same, and a solid electrolytic capacitor built-in module using the same according to Embodiment 1 of the present invention will be described with reference to the drawings.

  1 and 2 show the schematic configuration of a circuit board with a built-in solid electrolytic capacitor according to Embodiment 1 of the present invention. FIG. 1 is a cross-sectional configuration diagram in the thickness direction, and FIG. 2 is a cross-sectional configuration diagram in the plane direction of the substrate. However, here, only the upper and lower surfaces of the capacitor are determined for convenience of explanation, and the upper and lower surfaces are not particularly specified when using the circuit board with a built-in capacitor in the present embodiment. FIG. 3 is an enlarged view of a capacitor element forming portion on the surface of the valve metal body.

  A valve metal body 103 is disposed on the insulator 101. The metal sheet body 102 is preferably made of copper or nickel. The valve metal body 103 can be formed by making an aluminum foil porous by etching or the like. As shown in FIG. 3, a dielectric coating layer 104 is provided on the surface of the porous portion of the valve metal body 103, a solid electrolyte layer 105 is provided on the dielectric coating layer 104, and this solid electrolyte layer 105 is provided. A current collector 106 is provided thereon to form a capacitor element. The solid electrolyte layer 105 is a conductive polymer layer formed by chemical polymerization or electrolytic polymerization of a functional polymer such as polypyrrole or polythiophene, or a manganese dioxide layer by impregnating a manganese nitrate solution and then thermally decomposing it. It can be composed of Further, the current collector 106 can be a carbon layer alone or a laminated structure of a carbon layer and a silver paste layer. At this time, the GND area | region of a capacitor | condenser element can be strengthened by apply | coating a silver paste to the metal sheet body 102 simultaneously with an element part. In the present embodiment, the current collector 106 is directly connected to the metal sheet body 102 as an example of a method for connecting the current collector 106 and the metal sheet body 102 directly. This configuration is excellent in reducing the size of the element.

  The capacitor element and the metal sheet body 102 formed as described above are built in the circuit board. 107 is an inner via, and 108 is a wiring layer.

  As the insulator 101, an insulating resin of the circuit board and a resin different from the periphery of the capacitor element can be used. As the resin around the capacitor element, for example, a silicon resin or an epoxy resin can be used to obtain close contact with the entire metal foil. Further, as the insulating resin for the circuit board, for example, by using an epoxy resin, a phenol resin, or a cyanate resin having high heat resistance, the heat resistance of the electric insulating layer can be increased. As the thermoplastic resin, for example, a fluorine resin, a silicon resin, or the like can be used. By using a fluororesin, a resin composition layer having a low dielectric constant can be obtained. In addition, when a mixture of a filler and a resin is used as the insulating resin, the linear expansion coefficient, thermal conductivity, dielectric constant, and the like of the electrical insulating layer can be easily controlled by selecting the filler. For example, alumina, magnesia, boron nitride, aluminum nitride, silicon nitride, Teflon (registered trademark), silica, or the like can be used as the filler. By using alumina, boron nitride, or aluminum nitride, the thermal conductivity is increased, and the heat generated in the element portion can be effectively dissipated. Further, when silica is used, a resin composition layer having a low dielectric constant can be obtained, which is preferable for high frequency applications. Further, a dispersant, a colorant or a coupling agent may be included. By the dispersant, the filler in the resin can be dispersed with good uniformity. The resin composition layer can be colored with the colorant. Since the bonding agent can increase the adhesive strength between the resin and the filler, the insulation of the resin composition layer can be improved.

  The solid electrolyte layer 105 can be formed by chemical polymerization or electrolytic polymerization using a functional polymer such as polyprole or polythiophene.

  For the inner via 107, a conductive paste can be used. The wiring on the surface of the circuit board may be formed by a transfer method, etching, or a wiring board on which a board is formed in advance.

  Moreover, the circuit board with a built-in solid electrolytic capacitor of the present invention can be used as a multilayer wiring layer board by further stacking a wiring layer on the circuit board with a built-in solid electrolytic capacitor as shown in FIG. At this time, the insulator 101 does not need to be a single material, and may be configured differently from the insulator of the layer containing the capacitor and the insulator of the layer stacking the wiring layers. Furthermore, at this time, by forming the through hole 109 penetrating the insulator in the thickness direction, it is possible to easily secure the connection on both sides of the substrate. In this embodiment, the via is formed on the metal sheet body 102 as a method of exposing the cathode to the substrate surface. However, the configuration is not particularly limited, and the via may be provided on the current collector 106. .

(Embodiment 2)
FIG. 5 is a vertical sectional view of a circuit board with a built-in solid electrolytic capacitor according to Embodiment 2 of the present invention. In the figure, elements having the same names as those of the first embodiment have the same configuration as that of the first embodiment. In the circuit board with a built-in solid electrolytic capacitor shown in the second embodiment, the same metal as the valve metal body 203 in which the metal sheet body 202 performs element formation is used for the circuit board with a built-in solid electrolytic capacitor in the first embodiment. This makes it easy to configure and has excellent mass productivity.

(Embodiment 3)
6 and 7 show a schematic configuration of a circuit board with a built-in solid electrolytic capacitor according to Embodiment 3 of the present invention. 6 is a cross-sectional configuration diagram in the thickness direction, and FIG. 7 is a cross-sectional configuration diagram in the plane direction. In the figure, elements having the same names as those of the first embodiment have the same configuration as that of the first embodiment. In the circuit board with a built-in solid electrolytic capacitor shown in the third embodiment, there are a plurality of valve metal bodies 303 formed as elements with respect to the circuit board with a built-in solid electrolytic capacitor in the first embodiment. Each cathode is integrated with a current collector 306.

(Embodiment 4)
8 and 9 show a schematic configuration of a circuit board with a built-in solid electrolytic capacitor according to Embodiment 4 of the present invention. 8 is a cross-sectional configuration diagram in the thickness direction, and FIG. 9 is a cross-sectional configuration diagram in the plane direction. In the figure, elements having the same names as those of the third embodiment have the same configuration as that of the third embodiment. In the circuit board with a built-in solid electrolytic capacitor shown in the fourth embodiment, there are a plurality of valve metal bodies 403 formed on the circuit board with a built-in solid electrolytic capacitor according to the third embodiment. A metal sheet body 402 is disposed between them. By using this configuration, interference between capacitor elements can be suppressed.

(Embodiment 5)
The fifth embodiment is an example of a method for manufacturing the circuit board with a built-in solid electrolytic capacitor shown in FIG. The materials used in this embodiment are the same as those in FIG. 10A to 10E are cross-sectional views showing the steps of the method of manufacturing the circuit board with a built-in capacitor in the embodiment.

  First, as shown in FIG. 10A, the metal sheet body 502 and the valve metal body 503 are embedded in the insulator 501. At this time, the inner via 507 is formed.

  Next, as shown in FIG. 10B, a solid electrolyte layer 505 is formed on the surface of the valve metal body 503.

  Next, as shown in FIG. 10C, a conductive paste is applied as a current collector 506 so as to connect the solid electrolyte layer 505 and the metal sheet body 502.

  Next, as shown in FIG. 10D, a semi-cured thermosetting resin sheet 512 filled with an uncured conductive paste 511 and a copper foil 510 are formed and laminated to be integrated.

  Next, as shown in FIG. 10E, the semi-cured thermosetting resin sheet 512 filled with the conductive paste 511 is cured. A solid electrolytic capacitor element is built in the insulating layer.

  Next, as shown in FIG. 10F, the wiring layer 508 is obtained by patterning the surface copper foil 510 by etching. In this embodiment, the surface layer wiring is patterned by etching. However, the wiring forming method is not particularly limited, and the wiring layer 508 may be formed by a transfer method, or may be replaced with a copper foil. A fine wiring layer can be easily formed on the surface layer by laminating a multilayer substrate on which wiring is formed in advance.

(Embodiment 6)
The sixth embodiment is an example of a method for manufacturing the circuit board with a built-in solid electrolytic capacitor shown in FIG. The materials used in this embodiment are the same as those in FIG. FIG. 11A to FIG. 13H are cross-sectional views showing the steps of the method of manufacturing the circuit board with a built-in capacitor in the sixth embodiment.

  First, as shown in FIG. 11A, the valve metal body 603 is attached to the copper foil 610 through the insulator 601. The valve metal body 603 may be provided with a gap in advance.

  Next, as shown in FIG. 11B, the surface of the valve metal body 603 is patterned to divide the valve metal body into a plurality of parts. At this time, the insulator may be cut, but it is preferable to remove only the valve metal body on the surface layer without cutting the insulator. As a patterning method, the valve metal body 603 can be cut with a curve or a line segment having an arbitrary length by using a laser cutting method. Further, by using a dicing method as a patterning method, it is possible to perform highly accurate control in the depth direction of the cut.

  Next, as shown in FIG. 11C, an insulating resin 613 is applied to fill the cut grooves. In this embodiment, the insulating resin is applied. However, as the insulator 601 for attaching the valve metal body 603 to the copper foil 610, a semi-cured insulating resin is used and the insulating resin is changed to application, and the insulator 601 is heated. The insulator 601 may be filled in the cut groove by softening and melting with pressure.

  Next, as shown in FIG. 12D, a solid electrolyte layer 605 is formed on the surface of the desired valve metal body 603.

  Next, as shown in FIG. 12E, a conductive paste is used as a current collector 606 so as to connect the solid electrolyte layer 605 formed on the valve metal body and the valve metal body 603 not formed with the solid electrolyte layer. Apply.

  Next, as shown in FIG. 12F, an insulating resin and a copper foil 610 are laminated and integrated on the substrate of FIG. As the insulating resin at this time, a resin similar to the insulator 601 is used.

  Next, as shown in FIG. 13G, a through hole 609 is formed at an arbitrary place. Here, the anode can be exposed on the surface of the substrate by connecting the through hole to the valve metal body forming the capacitor element, and the conductive metal paste 605 or the valve metal body not formed with the solid electrolyte layer can be exposed. By connecting the through hole 609, the anode can be exposed on the surface of the substrate, and when it is not connected to either, it can be used as a signal line penetrating the substrate.

  Next, as shown in FIG. 13 (h), a wiring pattern 608 is obtained by patterning the surface copper foil 610 by etching. In this embodiment, the wiring pattern 608 on the surface layer is formed by etching. However, the wiring forming method is not particularly limited, and the wiring pattern may be formed by a transfer method. Instead, a fine wiring layer can be easily formed on the surface layer by laminating a multilayer substrate on which wiring is formed in advance.

  As described above, the circuit board with a built-in solid electrolytic capacitor according to the present invention, the method for forming the circuit board, and the module with a built-in solid electrolytic capacitor using the same can realize a circuit board with a built-in sheet-shaped solid electrolytic capacitor with reinforced GND. It can be applied to the use of circuit boards on which semiconductors are mounted.

Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in Embodiment 1 of this invention Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in Embodiment 1 of this invention The enlarged view of the principal part of the solid electrolytic capacitor in Embodiment 1 of this invention Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in Embodiment 1 of this invention Sectional drawing of the solid electrolytic capacitor built-in circuit board in Embodiment 2 of this invention Sectional drawing of the solid electrolytic capacitor built-in circuit board in Embodiment 3 of this invention Sectional drawing of the solid electrolytic capacitor built-in circuit board in Embodiment 3 of this invention Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in Embodiment 4 of this invention Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in Embodiment 4 of this invention Sectional drawing which shows the manufacturing method of the circuit board with a built-in solid electrolytic capacitor in Embodiment 5 of this invention Sectional drawing which shows the manufacturing method of the circuit board with a built-in solid electrolytic capacitor in Embodiment 6 of this invention Sectional drawing which shows the manufacturing method of the circuit board with a built-in solid electrolytic capacitor in Embodiment 6 of this invention Sectional drawing which shows the manufacturing method of the circuit board with a built-in solid electrolytic capacitor in Embodiment 6 of this invention

Explanation of symbols

101, 201, 301, 401, 501, 601 Insulator 102, 302, 402, 502, 602 Metal sheet body 103, 203, 303, 403, 503, 603 Valve metal body 104 Dielectric film layer 105, 205, 305, 405, 505, 605 Solid electrolyte layer 106, 206, 306, 406, 506, 606 Current collector 107, 207, 307, 407, 507 Inner via 108, 208, 308, 408, 508, 608 Wiring layer 109, 309, 409, 609 Through hole 510, 610 Copper foil 511 Conductive paste 512 Thermosetting resin sheet

Claims (19)

A valve metal sheet body;
A dielectric oxide film layer provided on the surface of the valve metal sheet body;
A solid electrolyte layer provided on the dielectric oxide film layer;
Built-in solid electrolytic capacitor element having a capacity forming portion composed of a cathode current collector provided on the solid electrolyte layer,
A metal sheet body electrically connected to the cathode current collector;
The circuit board with a built-in solid electrolytic capacitor, wherein the metal sheet body is arranged in substantially the same plane as the solid electrolytic capacitor element. The circuit board with a built-in solid electrolytic capacitor according to claim 1, wherein the metal sheet body is the same metal as the valve metal. The circuit board with a built-in solid electrolytic capacitor according to claim 1, wherein the valve metal porous sheet is an aluminum foil. 4. The solid electrolytic capacitor built-in circuit according to claim 1, wherein the dielectric oxide film layer provided on the surface of the valve metal sheet body is only one surface of the valve metal sheet body. substrate. The circuit board with a built-in solid electrolytic capacitor according to claim 4, wherein a metal layer is formed on a surface opposite to the surface on which the dielectric oxide film layer of the valve metal sheet body is provided. The circuit board with a built-in solid electrolytic capacitor according to claim 5, wherein the metal layer is nickel or copper. Having a plurality of the solid electrolytic capacitor elements on the same plane,
The circuit board with a built-in solid electrolytic capacitor according to claim 1, wherein each of the cathode current collector layers of the solid electrolytic capacitor element is electrically connected. The circuit board with a built-in solid electrolytic capacitor according to claim 7, wherein the metal body is disposed between the plurality of solid electrolytic capacitor elements on the same plane. The circuit board with a built-in solid electrolytic capacitor according to claim 1, wherein the valve metal body of the solid electrolytic capacitor element is electrically connected to a through hole penetrating the circuit board. An interposer used to configure an electronic device inserted between a wiring board and an electronic element mounted on the wiring board,
Using the circuit board with a built-in solid electrolytic capacitor according to any one of claims 1 to 9,
The interposer with a built-in electrolytic capacitor, wherein the capacitor element is continued on a power supply side. A method of manufacturing a circuit board with a built-in solid electrolytic capacitor according to claim 1,
Arranging the valve metal body and the metal sheet body on substantially the same plane;
Embedding the valve metal body in a semi-cured insulating resin containing at least a thermosetting resin in a shape in which a surface having a dielectric oxide film layer is exposed;
Placing the metal sheet on the surface of the insulating resin;
Forming a solid electrolyte layer on the dielectric oxide film layer;
A method of manufacturing a circuit board with a built-in solid electrolytic capacitor, comprising: forming a cathode current collector on the solid electrolyte layer; and electrically connecting the cathode current collector and the metal sheet body. A step of burying the valve metal body in a semi-cured insulating resin containing at least a thermosetting resin;
The step of arranging the metal sheet body on the surface of the insulating resin,
The method for manufacturing a circuit board with a built-in solid electrolytic capacitor according to claim 11, wherein the valve metal body and the metal sheet body are simultaneously embedded. A step of forming a cathode current collector on the solid electrolyte layer and a step of electrically connecting the cathode current collector and the metal sheet.
The method for producing a circuit board with a built-in solid electrolytic capacitor according to claim 11, wherein the method is performed simultaneously with conductive paste printing. A step of attaching a valve metal sheet body having an oxide film on a surface layer on a sheet-like insulator so that the oxide film is exposed;
Dividing the valve metal sheet body;
Filling the cut portion of the metal sheet with a second insulator;
Forming a solid electrolyte layer on the dielectric film on the surface of the valve metal body;
Forming a current collecting electrode on the surface of the solid electrolyte to form a capacitor element;
And a step of embedding the capacitor element in an insulator made of a thermosetting resin. The method of manufacturing a circuit board with a built-in solid electrolytic capacitor according to claim 14, wherein the insulator and the second insulator have the same material configuration. A step of attaching a valve metal sheet body having an oxide film on a surface layer on a semi-cured sheet-like insulator so that the oxide film is exposed;
Cutting and dividing the valve metal sheet body;
Heating and pressurizing and softening and melting the insulator to embed a cut portion of the valve metal sheet; and forming a solid electrolyte layer on the dielectric film on the surface of the valve metal body; and
Forming a current collecting electrode on the surface of the solid electrolyte to form a capacitor element;
And a step of embedding the capacitor element in an insulator made of a thermosetting resin. The method of manufacturing a circuit board with a built-in solid electrolytic capacitor according to claim 14, wherein the step of dividing the valve metal sheet body is laser processed. The method of manufacturing a circuit board with a built-in solid electrolytic capacitor according to claim 15, wherein the step of dividing the valve metal sheet body includes dicing the insulator. 19. A method for manufacturing a circuit board with a built-in solid electrolytic capacitor according to claim 14, further comprising a step of forming a hole in the valve metal sheet body before the step of attaching the valve metal sheet body to the insulator. A method of manufacturing a circuit board.

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