JP2008235545A - Electrolytic capacitor and wiring board as well as their manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolytic capacitor capable of obtaining larger capacity through a small occupying area without thickening a board. <P>SOLUTION: The electrolytic capacitor sheet has a valve metal sheet 11 whose surfaces except the side surfaces thereof are roughened, a metal oxide film 12 formed on the surface of the valve metal sheet 11, an anode lead-out electrode 15 conducted to the surface of the valve metal sheet 11 in the opening of the metal oxide film 12 formed on the upper surface side of the valve metal sheet 11, a solid electrolytic layer 13 formed on the surface of the metal oxide film 12 on the upper surface side of the valve metal sheet 11 and a cathode lead-out electrode 16 formed on the surface of the solid electrolytic layer 13. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrolytic capacitor sheet and a wiring board, and methods for manufacturing the same, and more particularly to an electrolytic capacitor sheet, a wiring board incorporating the electrolytic capacitor sheet, and a method for manufacturing the same.

  In portable electronic devices, the number of electronic components mounted on a wiring board is increasing more and more with the increase in functions. For example, a single frequency has been used for communication before, but in recent years, a plurality of frequency bands have been used, and a plurality of antennas and wireless circuits have become necessary. However, in a portable electronic device, since the area of the board on which the electronic component is mounted is limited, if the number of electronic parts increases, it cannot be mounted on the wiring board. On the other hand, in recent years, there has been an attempt to incorporate a part of the capacitor inside the wiring board.

  One method of incorporating a capacitor is to embed a ready-made capacitor component inside a wiring board. Since this method can use ready-made capacitor parts, it is easy to manufacture, but there is a problem in that the thickness of the ready-made capacitor parts is large, resulting in an increase in the thickness of the wiring board.

  In contrast to the above, instead of embedding off-the-shelf capacitor components inside the wiring board, in the multilayer wiring board manufacturing process, the capacitor element is formed as a part of the layer in the board, and then the multilayer wiring is built-up process There is a method of manufacturing a substrate. According to this method, since the capacitor element can be formed with a small thickness, the thickness of the wiring board can be reduced.

Patent Document 1 proposes an example of a wiring board in which capacitor elements are integrally formed in a multilayer wiring board manufacturing process. According to this document, when a wiring board is manufactured, a valve metal base is formed on an insulating resin substrate, an insulating oxide film is formed on the surface of the valve metal base by an anodic oxidation method, and then an insulating property is obtained. It describes that a polymer electrolyte layer is formed on the surface of an oxide film to form an electrolytic capacitor element.
JP 2001-176748 A

  As described above, when a ready-made capacitor component is embedded in the wiring board, the thickness of the ready-made capacitor component is large, which increases the thickness of the wiring board. On the other hand, in the manufacturing process of the multilayer wiring board, the conventional wiring board in which the capacitor elements are integrally formed has a problem that a large capacity cannot be obtained as compared with the ready-made capacitor elements.

  SUMMARY OF THE INVENTION In view of the above, the present invention provides an electrolytic capacitor sheet, a wiring board incorporating the electrolytic capacitor sheet, and a manufacturing method thereof, which can obtain a larger capacity with a small occupied area without increasing the thickness of the substrate. Objective.

In order to achieve the above object, the electrolytic capacitor sheet of the present invention comprises:
A valve metal sheet body having at least a first surface roughened, a first oxide film formed on the first surface, and a first conductive film connected to the first surface within an opening of the first oxide film. It has 1 extraction electrode, the 1st solid electrolyte layer formed on the surface of the said 1st oxide film, and the 2nd extraction electrode formed on the surface of this 1st solid electrolyte layer, It is characterized by the above-mentioned.

The wiring board according to the first aspect of the present invention is:
The electrolytic capacitor sheet described above,
First and second resin substrates respectively fixed to the first and second surfaces of the electrolytic capacitor sheet, the first and second resin substrates sandwiching the electrolytic capacitor sheet therebetween,
At least one of the first and second resin substrates includes a glass cloth,
The first and second lead electrodes are connected to a wiring layer formed on the surface of the first resin substrate through a via plug that penetrates the first resin substrate.

A wiring board according to a second aspect of the present invention is:
The electrolytic capacitor sheet as described above, wherein the valve metal sheet body has a roughened second surface facing the first surface, and is formed on the second surface. An electrolytic capacitor sheet further comprising an oxide film, a second solid electrolyte layer formed on the surface of the second oxide film, and a third lead electrode formed on the surface of the second solid electrolyte layer;
First and second resin substrates respectively fixed to the first and second surfaces of the electrolytic capacitor sheet, the first and second resin substrates sandwiching the electrolytic capacitor sheet therebetween,
At least one of the first and second resin substrates includes a glass cloth,
The first and second lead electrodes are connected to a wiring layer formed on the surface of the first resin substrate through a via plug that penetrates the first resin substrate,
The third lead electrode is connected to a wiring layer formed on the surface of the second resin substrate through a via plug penetrating the second resin substrate.

The method for producing an electrolytic capacitor sheet according to the first aspect of the present invention comprises:
A method for producing an electrolytic capacitor sheet, comprising:
Roughening at least the first surface of the valve metal sheet body;
Forming a metal oxide film on the first surface by using an anodic oxidation method;
Selectively removing the metal oxide film to form an opening;
Forming a solid electrolyte layer on the surface of the metal oxide film;
Forming a first extraction electrode conducting to the first surface of the valve metal sheet body in the opening of the metal oxide film and a second extraction electrode contacting the surface of the solid electrolyte layer, respectively. Features.

The manufacturing method of the electrolytic capacitor sheet according to the second aspect of the present invention is as follows.
A method for producing an electrolytic capacitor sheet, comprising:
Roughening the first and second surfaces of the valve metal sheet body;
Forming a metal oxide film on the first and second surfaces using an anodic oxidation method;
Selectively removing the metal oxide film formed on the first surface to form an opening;
Forming a solid electrolyte layer on the surface of the metal oxide film;
A first extraction electrode that conducts to the first surface of the valve metal sheet body within the opening of the metal oxide film; and a second extraction electrode that contacts the surface of the solid electrolyte layer formed on the first surface. Forming a third lead electrode in contact with the surface of the solid electrolyte layer formed on the second surface.

A method for manufacturing a wiring board according to a first aspect of the present invention includes:
A method of manufacturing a wiring board having an electrolytic capacitor sheet,
Producing an electrolytic capacitor sheet by the electrolytic capacitor sheet producing method according to the first aspect of the present invention;
A step of fixing a resin substrate having a window at a position corresponding to at least the first and second lead electrodes of the electrolytic capacitor sheet to the first surface, the resin substrate comprising a glass cloth, and
Forming a wiring connected to the first and second lead electrodes and extending on the surface of the resin substrate through the window.

A method for manufacturing a wiring board according to a second aspect of the present invention includes:
A method of manufacturing a wiring board having an electrolytic capacitor sheet,
Producing an electrolytic capacitor sheet by the electrolytic capacitor sheet producing method according to the second aspect of the present invention;
Fixing a first resin substrate made of a resin including glass cloth and having a window at a position corresponding to at least the first and second lead electrodes of the electrolytic capacitor sheet on the first surface of the electrolytic capacitor sheet; ,
Fixing a second resin substrate made of a resin containing glass cloth and having an electrode pad at a position corresponding to at least a third lead electrode of the electrolytic capacitor sheet on the second surface of the electrolytic capacitor sheet;
Forming a wiring connected to the first and second lead electrodes and extending on the surface of the first resin substrate through the window.

  According to the electrolytic capacitor sheet of the present invention, since the first surface of the valve metal sheet body is roughened, the surface area can be increased and the capacitor capacity can be effectively increased. Further, since the first and second lead electrodes are formed on the first surface side of the valve metal sheet body without pulling out the electrodes in the surface direction of the valve metal sheet body, the area of the wiring board necessary for capacitor formation is reduced. it can. For this reason, a large capacitor capacity can be obtained with a small occupied area in the wiring board.

  Since the electrolytic capacitor sheet of the present invention does not mold the valve metal sheet body to form a surface mount component, the thickness can be made substantially equal to the thickness of the valve metal sheet body. In a preferred embodiment of the electrolytic capacitor sheet of the present invention, it is possible to further reduce the thickness by removing the roughened portion on one side of the valve metal sheet body.

In a preferred embodiment of the electrolytic capacitor sheet of the present invention,
The valve metal sheet body has a roughened second surface facing the first surface;
A second oxide film formed on the second surface; a second solid electrolyte layer formed on the surface of the second oxide film; and a third lead formed on the surface of the second solid electrolyte layer An electrode.
By forming the capacitor portion also on the second surface side of the valve metal sheet body, the capacitor capacity per occupied area can be effectively increased.

  In a preferred aspect of the electrolytic capacitor sheet of the present invention, the first solid electrolyte layer is not formed on the surface portion of the oxide film adjacent to the opening. The semiconductor device further includes an insulating layer that insulates between the first solid electrolyte layer and the first extraction electrode. The solid electrolyte layer and the first extraction electrode can be more reliably insulated.

  In the electrolytic capacitor sheet of the present invention, the valve metal sheet body may include at least one metal selected from the group consisting of aluminum, tantalum, niobium, titanium, and zirconium.

  According to the wiring board of the present invention, when at least one of the first and second resin boards includes the glass cloth, it is possible to provide a wiring board that is light and has high strength. In addition, since the via holes can be formed at a narrow pitch in the resin substrate including the glass cloth, the integration rate can be increased. The wiring board of the present invention can be suitably used as a wiring board for LSI (Large Scale Integration) decoupling, for example.

  In a preferred aspect of the wiring board of the present invention, the first solid electrolyte layer is not formed on the surface portion of the oxide film adjacent to the opening. In addition, an insulating layer is further provided for insulating between the solid electrolyte layer and the first extraction electrode.

  In the wiring board of the present invention, the valve metal sheet body may include at least one metal selected from the group consisting of aluminum, tantalum, niobium, titanium, and zirconium.

  In the method for manufacturing a wiring board according to the first aspect of the present invention, a resin substrate made of a resin containing glass cloth and having a window at a position corresponding to at least the first and second extraction electrodes of the electrolytic capacitor sheet is provided in the first. The step of fixing to the surface of 1 includes a step of forming a resin substrate made of resin containing glass cloth on the first surface, and a window at a position of the resin substrate corresponding to at least the first and second extraction electrodes of the electrolytic capacitor sheet. May be included.

  In the method for manufacturing a wiring board according to the second aspect of the present invention, a first resin substrate made of a resin containing glass cloth and having windows at positions corresponding to at least the first and second lead electrodes of the electrolytic capacitor sheet is provided. The step of fixing onto the first surface of the electrolytic capacitor sheet includes the step of forming a first resin substrate made of a resin containing glass cloth on the first surface of the electrolytic capacitor sheet; Forming a window at a position of the first resin substrate corresponding to the first and second extraction electrodes.

  In the method for manufacturing a wiring board according to the second aspect of the present invention, an electrolytic capacitor including a plurality of electrolytic capacitor sheets in the process of manufacturing the electrolytic capacitor sheet by the method for manufacturing an electrolytic capacitor sheet according to the second aspect of the present invention. Prior to the step of manufacturing the sheet body and fixing the first resin substrate on the first surface of the electrolytic capacitor sheet, the second resin substrate is fixed on the second surface of the electrolytic capacitor sheet body. Subsequent to the step, the electrolytic capacitor sheet may be cut into individual electrolytic capacitor sheets by etching. An electrolytic capacitor sheet having a small planar shape can be formed in the wiring substrate at a narrow pitch.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. FIG. 1 is a plan view of the electrolytic capacitor sheet according to the first embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. The electrolytic capacitor sheet 1 includes a valve metal sheet body 11. The surface of the valve metal sheet body 11 is roughened except for the side surfaces, and has an uneven shape.

  On the surface of the valve metal sheet body 11, a metal oxide film 12 is formed along the surface irregularities except for the valve metal sheet exposed region (opening of the first oxide film) 21 on the upper surface side. On the upper surface side of the valve metal sheet body 11 and on the surface of the metal oxide film 12, the solid electrolyte layer 13 is formed except for the insulating region 22 around the valve metal sheet exposed region 21. An anode lead electrode (first lead electrode) 15 is formed on the valve metal sheet body 11 via the contact electrode layer 14 in the center of the valve metal sheet exposed region 21. On the upper surface side of the valve metal sheet body 11, a cathode lead electrode (second lead electrode) 16 is formed on a part of the solid electrolyte layer 13 via the contact electrode layer 14.

  The insulating region 22 is provided to electrically insulate the anode lead electrode 15 and the cathode lead electrode 16 from each other. The valve metal sheet body 11 constitutes the anode of the capacitor, and the solid electrolyte layer 13 constitutes the cathode of the capacitor. The portion where the solid electrolyte layer 13 is formed contributes to the capacitor capacity in the electrolytic capacitor sheet 1.

  According to the electrolytic capacitor sheet 1 of the present embodiment, the surface of the valve metal sheet body 11 has an uneven shape and a large surface area. Further, since the anode lead electrode 15 and the cathode lead electrode 16 are formed on the upper surface side of the valve metal sheet body 11 without pulling out the anode and the cathode in the surface direction of the valve metal sheet body 11, the wiring board necessary for capacitor formation is formed. The area can be reduced. For this reason, a large capacitor capacity can be obtained with a small occupied area in the wiring board. In the electrolytic capacitor sheet 1, for example, by reducing the thickness of the metal oxide film 12, a capacitor capacity of 0.1 μF or more per 1 mm square (□ 1 mm) can be obtained.

  Depending on the type of metal, the valve metal sheet body 11 with a roughened surface can be obtained inexpensively on a roll basis, for example, for an anode sheet of an electrolytic capacitor. Therefore, the production cost of the electrolytic capacitor sheet 1 can be greatly reduced.

  The roughening of the lower surface of the valve metal sheet body 11 is not necessarily required, and the metal oxide film 12 on the lower surface side of the valve metal sheet body 11 is not necessarily required. The solid electrolyte layer 13 desirably has a low viscosity at the time of formation so that the cathode can be formed over a wide range of the roughened surface. Therefore, a conductive organic compound such as polypyrrole is more suitable than a conductive material obtained by pasting metal powder.

  The extraction electrodes 15 and 16 are made by electrolytic plating, electroless plating, or the like. When a metal having excellent electrical conductivity such as copper is formed with a thickness of several μm to several tens of μm, the equivalent series resistance (ESR) of the capacitor can be lowered. . The lead electrodes 15 and 16 are preferably subjected to nickel plating or gold plating on the surface in order to improve the connection with the wiring board.

  3 and 4 are a top view and a bottom view of the electrolytic capacitor sheet according to the second embodiment of the present invention, and FIG. 5 is a cross-sectional view taken along line VV in FIGS. In the electrolytic capacitor sheet 2 of the present embodiment, a solid electrolyte layer 13 is also formed on the lower surface side of the valve metal sheet body 11 in addition to the configuration of the electrolytic capacitor sheet 1 shown in FIGS. In addition, a lower surface cathode lead electrode (third lead electrode) 17 is formed on a part of the solid electrolyte layer 13 on the lower surface side of the valve metal sheet body 11 via a contact electrode layer 14.

  According to the electrolytic capacitor sheet 2 of the present embodiment, a capacitor portion is also formed on the lower surface side of the valve metal sheet body 11 so that the capacitor capacity per occupied area is compared with that of the electrolytic capacitor sheet 1 of FIGS. Can be almost doubled.

  6 is a plan view of an electrolytic capacitor sheet according to a third embodiment of the present invention, and FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. In the electrolytic capacitor sheet 3 of the present embodiment, a resin insulating layer 18 is formed around the anode lead electrode 15 in addition to the configuration of the electrolytic capacitor sheet 1 shown in FIGS. The resin insulating layer 18 is formed in the valve metal sheet exposed region 21 and its periphery, and the outer edge is in contact with the solid electrolyte layer 13. A part of the solid electrolyte layer 13 is formed on the resin insulating layer 18.

  According to the electrolytic capacitor sheet 3 of the present embodiment, by forming the resin insulating layer 18, the solid electrolyte layer 13 and the anode lead electrode 15 can be more reliably insulated. The resin insulating layer 18 is preferably made of a photosensitive resin such as a photosensitive epoxy resin, a photosensitive phenol resin, a photosensitive polyimide resin, or a photosensitive BCB (benzocyclobutene) resin.

  FIG. 8 is a cross-sectional view of a wiring board incorporating an electrolytic capacitor sheet according to the fourth embodiment of the present invention. The wiring board 101 of this embodiment includes the electrolytic capacitor sheet 1 shown in FIGS. The electrolytic capacitor sheet 1 is fixed by an adhesive 113 on a resin substrate 111 including a glass cloth. A resin sheet 112 made of the same material as the resin substrate 111 is formed on the resin substrate 111 so as to cover the electrolytic capacitor sheet 1. The resin substrate 111 and the resin sheet 112 are laminated by thermocompression bonding via the electrolytic capacitor sheet 1 and are collectively referred to as a core substrate 114.

  The resin sheet 112 is formed with a via hole 115 reaching the anode lead electrode 15 or the cathode lead electrode 16 formed on the electrolytic capacitor sheet 1, and the copper hole is continuously formed in the via hole 115 and on the resin sheet 112. Via electrodes (inner vias) 116 are formed by plating or the like. A portion of the via electrode 116 formed on the resin sheet 112 constitutes a land. A dummy ground pattern 123 is formed on the lower surface of the resin substrate 111.

  A buildup resin layer 117 is formed on the upper surface side of the core substrate 114 so as to cover the via electrode 116. The build-up resin layer 117 is formed to reduce the stress generated in the electrolytic capacitor sheet 1 and is made of a resin having a small elastic modulus. Further, unlike the resin substrate 111 and the resin sheet 112, it is not necessary to include a glass cloth. A via hole 119 reaching the via electrode 116 is formed in the buildup resin layer 117, and the via electrode 120 is formed continuously in the via hole 119 and on the buildup resin layer 117. The portion of the via electrode 120 formed on the buildup resin layer 117 constitutes a land.

  In order to reduce the warpage of the wiring substrate 101, a buildup resin layer 118 is also formed on the lower surface side of the core substrate 114, and via holes 119 and via electrodes 120 are also formed in the buildup resin layer 118. The via electrode 120 is connected to the ground pattern 123. Since it is necessary to form a fine wiring pattern at a narrower pitch than the core substrate 114 in the buildup resin layer 117, the thickness of the buildup resin layer 117 is preferably smaller than that of the resin sheet 112.

  FIG. 9 is a cross-sectional view of a wiring board incorporating an electrolytic capacitor sheet according to a fifth embodiment of the present invention. The wiring board 102 of the present embodiment is not formed with the resin sheet 112, and the build-up resin layer 117 is formed on the resin board 111 so as to cover the electrolytic capacitor sheet 1. Different from the substrate 101. The resin substrate 111 and the buildup resin layer 117 are laminated by thermocompression bonding via the electrolytic capacitor sheet 1. The via hole 119 of the buildup resin layer 117 reaches the anode lead electrode 15 or the cathode lead electrode 16 formed on the electrolytic capacitor sheet 1.

  In the wiring board 102 of this embodiment, since the resin sheet 112 is omitted, the via electrode 120 can be directly connected to the anode lead electrode 15 or the cathode lead electrode 16 without using an inner via. Note that in the case where the routing of LSI signal lines, power supply lines, or ground lines is complicated, two or more build-up resin layers may be laminated. Since the build-up resin layer 117 is often thinner than the resin substrate 111 and the resin sheet 112, in this embodiment, the thickness of the electrolytic capacitor sheet 1 is approximately 100 μm or less, preferably 80 μm or less, except for the adhesive 113. It is suitable for the case.

  FIG. 10 is a cross-sectional view of a wiring board incorporating an electrolytic capacitor sheet according to a sixth embodiment of the present invention. The wiring board 103 of this embodiment has the electrolytic capacitor sheet 2 shown in FIGS. Vias 121 are formed in the resin substrate 111, and pads 122 are formed on the upper surface of the resin substrate 111 so as to be connected to the vias 121. The bottom of the via 121 is connected to a ground pattern 123 formed on the lower surface of the resin substrate 111. The pad 122 is connected to the lower surface cathode lead electrode 17 of the electrolytic capacitor sheet 2, and the ground pattern 123 is connected to the via electrode 120 formed in the buildup resin layer 118.

  In the wiring board 103 of the present embodiment, the lower surface side of the valve metal sheet body 11 is also used as a capacitor, so that the capacitor capacity per occupied area is almost twice that of the electrolytic capacitor sheet 1 of FIGS. I can do it.

  The ground pattern 123 may be drawn to the upper surface of the core substrate 114 or the upper surface of the wiring substrate 103 through vias that penetrate the core substrate 114. Further, as shown in FIG. 9, a buildup resin layer may be formed on the resin substrate 111 so as to cover the electrolytic capacitor sheet 2. Furthermore, a cover resin layer may be formed on the solid electrolyte layer 13 formed on the lower surface of the electrolytic capacitor sheet 2, and the cover resin layer and the upper surface of the resin substrate 111 may be fixed with an adhesive 113.

  FIG. 11 is an enlarged cross-sectional view showing the vicinity of the anode lead electrode 15 in the wiring board incorporating the electrolytic capacitor sheet according to the seventh embodiment of the present invention. The wiring board 104 of this embodiment includes the electrolytic capacitor sheet 3 shown in FIGS. A resin sheet 112 made of the same material as the resin substrate 111 is formed on the resin substrate 111 so as to cover the electrolytic capacitor sheet 3.

  As in the third embodiment, a photosensitive resin such as a photosensitive epoxy resin, a photosensitive phenol resin, a photosensitive polyimide resin, or a photosensitive BCB (benzocyclobutene) resin is preferably used for the resin insulating layer 18. The photosensitive polyimide resin or the photosensitive BCB resin often requires a temperature of 300 ° C. or higher upon curing, and the valve metal sheet body 11 may be oxidized or the solid electrolyte layer 13 may be decomposed. is there. Therefore, a photosensitive epoxy resin or a photosensitive phenol resin that cures at a lower temperature is more preferable.

  In this embodiment, instead of the resin sheet 112 including glass cloth, a buildup resin layer may be formed on the resin substrate 111 so as to cover the electrolytic capacitor sheet 3 as shown in FIG. Further, as shown in FIG. 10, the lower surface side of the electrolytic capacitor sheet is the same as the electrolytic capacitor sheet 2 shown in FIG. 5, and the lower surface cathode lead electrode is connected to a pad electrically connected to the ground pattern. It may be a configuration.

  12A to 12J are cross-sectional views sequentially showing respective manufacturing steps for manufacturing the wiring board 101 shown in FIG. First, as shown in FIG. 12A, a metal oxide film 12 is formed on the surface of the valve metal sheet body 11 having a roughened surface by an anodic oxidation method or the like (FIG. 12B). The metal oxide film 12 is formed to a thickness of several tens nm to several hundreds nm. Next, the metal oxide film 12 outside the capacitor forming region 23 and the valve metal sheet exposed region 21 is selectively removed by a chemical etching method (FIG. 12C). When the metal oxide film 12 is removed, finer patterning can be performed by pasting a dry resist on the surface in advance and forming a resist pattern by photolithography, followed by chemical etching.

  Subsequently, the solid electrolyte layer 13 is selectively formed on the metal oxide film 12 left on the upper surface side of the valve metal sheet body 11 without being removed by etching (FIG. 12D). For the solid electrolyte layer 13, a conductive organic compound such as polypyrrole is more suitable than a powder such as manganese dioxide impregnated with sulfuric acid. In order to selectively form the solid electrolyte layer 13, a printing method using a mesh screen or a metal mask is suitable. Next, the anode lead electrode 15 and the cathode lead electrode 16 are formed by plating or the like (FIG. 12E). The anode lead electrode 15 is formed on the valve metal sheet body 11 at the center of the valve metal sheet exposed region 21, and the cathode lead electrode 16 is formed on the solid electrolyte layer 13.

  Next, the sheet body including the valve metal sheet body 11 is pasted onto the resin substrate 111 made of a resin including glass cloth via the adhesive 113 (FIG. 12F). In the example of the figure, a dummy ground pattern 123 is formed on the lower surface of the resin substrate 111. Subsequently, the electrolytic capacitor sheet 1 is obtained by removing the valve metal sheet body 11 outside the capacitor forming region 23 by a chemical etching method (FIG. 12G).

  Next, a resin sheet 112 made of the same material as the resin substrate 111 is prepared, and a notch 131 is formed in the resin sheet 112 according to the planar shape of the electrolytic capacitor sheet 1 (FIG. 12H). Subsequently, the electrolytic capacitor sheet 1 is covered and the resin sheet 112 is laminated on the resin substrate 111 and integrated by thermocompression bonding. As a result, a core substrate 114 made of the resin substrate 111 and the resin sheet 112 for accommodating the electrolytic capacitor sheet 1 is formed.

  Furthermore, after the via hole 115 reaching the anode lead electrode 15 or the cathode lead electrode 16 from the upper surface of the resin sheet 112 is opened with a laser, the inside of the via hole 115 and the surface of the resin sheet 112 are continuously formed by metallization such as a copper plating method. The via electrode 116 to be formed is formed (FIG. 12I).

  Next, build-up resin layers 117 and 118 made of a material different from that of the resin substrate 111 are stacked on top and bottom of the core substrate 114 and integrated by thermocompression bonding (FIG. 12J). Subsequently, a via hole 119 reaching the land portion of the via electrode 116 from the upper surface of the buildup resin layer 117 or the lower surface of the buildup resin layer 118 is opened by laser, and then the inside of the via hole 119 and the surface of the resin sheet 112 are formed by metallization. A via electrode 120 that is continuous is formed. In this way, lands connected to the electrodes of the built-in electrolytic capacitor sheet 1 are formed, and the wiring substrate 101 incorporating the electrolytic capacitor sheet 1 shown in FIG. 8 is manufactured.

  According to the present manufacturing method, after the sheet body including the valve metal sheet body 11 is attached to the resin substrate 111, unnecessary portions are removed by etching, so that the electrolytic capacitor sheet 1 having a small planar shape is placed in the wiring substrate 101. It can be formed with a narrow pitch. Further, since it is not necessary to individually mount the electrolytic capacitor sheet 1 on the resin substrate 111, the manufacturing process can be simplified.

  FIG. 13 is a cross-sectional view showing one manufacturing stage for manufacturing the wiring board 102 shown in FIG. Of the manufacturing steps shown in FIGS. 12A to 12J, FIGS. 12A to 12G are common to the present manufacturing method. Subsequent to FIG. 12G, build-up resin layers 117 and 118 made of a material different from that of the resin substrate 111 are laminated from the upper and lower surfaces of the resin substrate 111 and integrated by thermocompression bonding (FIG. 13).

  Next, via holes 115 reaching the anode lead electrode 15, the cathode lead electrode 16, or the ground pattern 123 from the top surface of the buildup resin layer 117 and the bottom surface of the buildup resin layer 118 are opened with a laser, and then the inside of the via hole 115. And the via electrode 116 is continuously formed on the buildup resin layers 117 and 118. As a result, lands connected to the electrodes of the built-in electrolytic capacitor sheet 1 are formed, and the wiring substrate 102 containing the electrolytic capacitor sheet shown in FIG. 9 is manufactured.

  According to this manufacturing method, since the buildup resin layer 117 is directly laminated on the electrolytic capacitor sheet 1, a wiring board having a small thickness can be manufactured as compared with the manufacturing method shown in FIGS. 12A to 12J. In addition, since the thickness of the buildup resin layer 117 is often smaller than the thickness of the resin sheet 112, the electrolytic capacitor sheet 1 is preferably formed to have a thickness smaller than that of the manufacturing method illustrated in FIGS.

  14A to 14G are cross-sectional views sequentially showing manufacturing steps for manufacturing the wiring board 103 shown in FIG. Of the manufacturing steps shown in FIGS. 12A to 12J, FIGS. 12A to 12C are common to the present manufacturing method. Subsequent to FIG. 12C, a solid electrolyte layer 13 is formed on the upper and lower metal oxide films 12 (FIG. 14A). Subsequently, an anode extraction electrode 15 and a cathode extraction electrode 16 are formed on the upper surface side, and a lower surface cathode extraction electrode 17 is formed on the lower surface side (FIG. 14B). The anode lead electrode 15 is formed on the valve metal sheet body 11 at the center of the valve metal sheet exposed region 21, and the cathode lead electrode 16 and the bottom cathode lead electrode 17 are formed on the solid electrolyte layer 13, respectively.

  Next, a resin substrate 111 is prepared. In the resin substrate 111, a via 121 penetrating the substrate, a pad 122 connected to the via 121 on the upper surface, and a ground pattern 123 connected to the via 121 on the lower surface are formed in advance. Subsequently, the lower surface of the sheet body including the valve metal sheet body 11 is fixed on the resin substrate 111. When the sheet body is fixed, the lower surface cathode lead electrode 17 is electrically connected to the pad 122 using a conductive resin or the like, and other portions are bonded through the adhesive 113 (FIG. 14C).

  The thickness of the adhesive 113 needs to be large enough to absorb the thickness of the lower cathode lead electrode 17. Accordingly, when the adhesive 113 is formed on the resin substrate 111, a method of supplying the liquid adhesive with a dispenser or the like is not suitable, and a solid adhesive such as a paste adhesive or a die bonding sheet may be used. preferable. Subsequently, the electrolytic capacitor sheet 2 is obtained by removing the valve metal sheet body 11 outside the capacitor forming region 23 by a chemical etching method (FIG. 14D). 14E to 14G, the wiring substrate 103 incorporating the electrolytic capacitor sheet 2 shown in FIG. 10 is manufactured by performing the same procedure as in FIGS. 12H to 12J.

  According to this manufacturing method, since the lower surface side of the electrolytic capacitor sheet 2 can also be used as a capacitor, the capacity per occupied area can be approximately doubled compared to an example in which only the upper surface side is used as a capacitor.

  15A to 15H are cross-sectional views sequentially showing each manufacturing stage for manufacturing the wiring board 104 shown in FIG. Of the manufacturing steps shown in FIGS. 12A to 12J, FIGS. 12A to 12C are common to the present manufacturing method. Subsequent to FIG. 12C, the anode lead electrode 15 is formed on the valve metal sheet body 11 at the center of the valve metal sheet exposed region 21 (FIG. 15A).

  Subsequently, after forming the anode insulating electrode 15, the valve metal sheet exposed region 21 around the anode extracting electrode 15, and the resin insulating layer 18 covering a part of the metal oxide film 12, a part of the resin insulating layer 18 is opened. Then, a part of the anode lead electrode 15 is exposed (FIG. 15B). A photosensitive resin is preferably used for opening the resin insulating layer 18. As the photosensitive resin, a photosensitive epoxy resin and a photosensitive phenol resin are preferable. The resin insulating layer 18 may be opened with a laser using a non-photosensitive resin.

  After forming the solid electrolyte layer 13 on the metal oxide film 12 on the upper surface side of the valve metal sheet body 11, the cathode lead electrode 16 is formed on the solid electrolyte layer 13 (FIG. 15C). When forming the solid electrolyte layer 13, a part thereof may cover the resin insulating layer 18.

  After a sheet body including the valve metal sheet body 11 is attached to a resin substrate 111 made of a resin including glass cloth via an adhesive 113 (FIG. 15D), the valve metal sheet body 11 outside the capacitor forming region 23 is attached. The electrolytic capacitor sheet 3 is obtained by removing by chemical etching (FIG. 15E). 15F to 15H, the wiring substrate 104 incorporating the electrolytic capacitor sheet 3 shown in FIG. 11 is manufactured by performing the same procedure as in FIGS. 12H to 12J.

  According to this manufacturing method, the anode insulating electrode 15 and the solid electrolyte layer 13 can be more reliably insulated by the resin insulating layer 18, and the reliability of the electrolytic capacitor sheet 3 or the wiring substrate 104 can be improved.

  FIG. 16 is a plan view of an electrolytic capacitor sheet according to a modification of the third embodiment, and FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. The electrolytic capacitor sheet 4 is a valve metal sheet in the electrolytic capacitor sheet 3 of the third embodiment shown in FIGS. 6 and 7, except that the resin insulating layer 18 is not only around the anode lead electrode 15 but also the cathode lead electrode 16. It is formed on the entire upper surface of the body 11. The resin insulating layer 18 is formed so as to cover the solid electrolyte layer 13.

  In the electrolytic capacitor sheet 4 of this modification, since the resin insulating layer 18 is formed on the entire upper surface side excluding the cathode lead electrode 16, it also functions as a protective film for protecting the electrolytic capacitor sheet 4. The solid electrolyte layer 13 and the lower cathode lead electrode 17 may be formed on the lower surface side of the electrolytic capacitor sheet 4, and the resin insulating layer 18 is formed on the lower surface solid electrolyte 13 except for the lower cathode lead electrode 17. May be.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, the electrolytic capacitor sheet | seat and wiring board of this invention, and those manufacturing methods are not limited only to the structure of the said embodiment, The above-mentioned What changed and changed variously from the structure of embodiment is also contained in the scope of the present invention.

It is a top view of the electrolytic capacitor sheet concerning a 1st embodiment of the present invention. It is sectional drawing which follows the II-II line of FIG. It is a top view of the electrolytic capacitor sheet concerning a 2nd embodiment of the present invention. It is a bottom view of the electrolytic capacitor sheet which concerns on 2nd Embodiment of this invention. It is sectional drawing which follows the VV line | wire of FIG. It is a top view of the electrolytic capacitor sheet concerning a 3rd embodiment of the present invention. It is sectional drawing which follows the VII-VII line of FIG. It is sectional drawing of the wiring board which concerns on 4th Embodiment of this invention. It is sectional drawing of the wiring board which concerns on 5th Embodiment of this invention. It is sectional drawing of the wiring board which concerns on 6th Embodiment of this invention. It is sectional drawing of the wiring board which concerns on 7th Embodiment of this invention. FIG. 9 is a cross-sectional view showing a manufacturing stage for manufacturing the wiring board shown in FIG. 8. FIG. 12B is a cross-sectional view showing a manufacturing step subsequent to FIG. 12A. FIG. 12B is a cross-sectional view showing a manufacturing step subsequent to FIG. 12B. 12D is a cross-sectional view showing a manufacturing step subsequent to FIG. 12C. FIG. 12D is a cross-sectional view showing a manufacturing step subsequent to FIG. 12D. FIG. FIG. 12D is a cross-sectional view showing a manufacturing step subsequent to FIG. 12E. 12D is a cross-sectional view showing a manufacturing step subsequent to FIG. 12F. FIG. 12G is a cross-sectional view showing a manufacturing step subsequent to FIG. 12G. FIG. 12D is a cross-sectional view showing a manufacturing step subsequent to FIG. 12H. FIG. FIG. 12D is a cross-sectional view showing a manufacturing step subsequent to FIG. 12I. FIG. 10 is a cross-sectional view showing one manufacturing stage for manufacturing the wiring board shown in FIG. 9. FIG. 11 is a cross-sectional view showing one stage of manufacturing the wiring board shown in FIG. 10. FIG. 14B is a cross-sectional view showing a manufacturing step subsequent to FIG. 14A. FIG. 14B is a cross-sectional view showing a manufacturing step subsequent to FIG. 14B. FIG. 14D is a cross-sectional view showing a manufacturing step subsequent to FIG. 14C. FIG. 14D is a cross-sectional view showing a manufacturing step subsequent to FIG. 14D. FIG. 14E is a cross-sectional view showing a manufacturing step that follows FIG. 14E. FIG. 14F is a cross-sectional view showing a manufacturing step that follows FIG. 14F. FIG. 12 is a cross-sectional view showing one stage of manufacturing the wiring board shown in FIG. 11. FIG. 15B is a cross-sectional view showing a manufacturing step subsequent to FIG. 15A. FIG. 15B is a cross-sectional view showing a manufacturing step that follows FIG. 15B. FIG. 15D is a cross-sectional view showing a manufacturing step subsequent to FIG. 15C. FIG. 15D is a cross-sectional view showing a manufacturing step subsequent to FIG. 15D. FIG. 15E is a cross-sectional view showing a manufacturing step that follows FIG. 15E. FIG. 15F is a cross-sectional view showing a manufacturing step that follows FIG. 15F. FIG. 15G is a cross-sectional view showing a manufacturing step that follows FIG. 15G. It is a top view of the electrolytic capacitor sheet which concerns on the modification of 3rd Embodiment. It is sectional drawing which follows the XVII-XVII line of FIG.

Explanation of symbols

1-4: Electrolytic capacitor sheet 11: Valve metal sheet body 12: Metal oxide film 13: Solid electrolyte layer 14: Adhesive electrode layer 15: Anode lead electrode (first lead electrode)
16: cathode extraction electrode (second extraction electrode)
17: Bottom cathode lead electrode (third lead electrode)
18: Resin insulating layer 21: Valve metal sheet exposed region 22: Insulating region 23: Capacitor forming region 101-104: Wiring substrate 111: Resin substrate 112: Resin sheet 113: Adhesive 114: Core substrate 115: Via hole 116: Via electrode (Inner via)
117: Build-up resin layer 118: Build-up resin layer 119: Via hole 120: Via electrode 121: Via 122: Pad 123: Ground pattern 131: Notch

Claims (14)

  A valve metal sheet body having at least a first surface roughened, a first oxide film formed on the first surface, and a first conductive film connected to the first surface within an opening of the first oxide film. An electrolytic capacitor comprising: one lead electrode; a first solid electrolyte layer formed on the surface of the first oxide film; and a second lead electrode formed on the surface of the first solid electrolyte layer. Sheet. The valve metal sheet body has a roughened second surface facing the first surface;
A second oxide film formed on the second surface; a second solid electrolyte layer formed on the surface of the second oxide film; and a third lead formed on the surface of the second solid electrolyte layer The electrolytic capacitor sheet according to claim 1, further comprising an electrode.   The electrolytic capacitor sheet according to claim 1 or 2, wherein the first solid electrolyte layer is not formed on a surface portion of the oxide film adjacent to the opening.   The electrolytic capacitor sheet according to claim 1, further comprising an insulating layer that insulates between the first solid electrolyte layer and the first lead electrode.   The electrolytic capacitor sheet according to any one of claims 1 to 4, wherein the valve metal sheet body includes at least one metal selected from the group consisting of aluminum, tantalum, niobium, titanium, and zirconium. The electrolytic capacitor sheet according to claim 1;
First and second resin substrates respectively fixed to the first and second surfaces of the electrolytic capacitor sheet, the first and second resin substrates sandwiching the electrolytic capacitor sheet therebetween,
At least one of the first and second resin substrates includes a glass cloth,
The wiring board, wherein the first and second lead electrodes are connected to a wiring layer formed on a surface of the first resin substrate through a via plug that penetrates the first resin substrate. The electrolytic capacitor sheet according to claim 2,
First and second resin substrates respectively fixed to the first and second surfaces of the electrolytic capacitor sheet, the first and second resin substrates sandwiching the electrolytic capacitor sheet therebetween,
At least one of the first and second resin substrates includes a glass cloth,
The first and second lead electrodes are connected to a wiring layer formed on the surface of the first resin substrate through a via plug that penetrates the first resin substrate,
The wiring board, wherein the third lead electrode is connected to a wiring layer formed on a surface of the second resin substrate through a via plug penetrating the second resin substrate.   The wiring board according to claim 6 or 7, wherein the first solid electrolyte layer is not formed on a surface portion of an oxide film adjacent to the opening.   The wiring board according to claim 6, further comprising an insulating layer that insulates between the first solid electrolyte layer and the first extraction electrode.   The wiring board according to any one of claims 6 to 9, wherein the valve metal sheet body includes at least one metal selected from the group consisting of aluminum, tantalum, niobium, titanium, and zirconium. A method for producing an electrolytic capacitor sheet, comprising:
Roughening at least the first surface of the valve metal sheet body;
Forming a metal oxide film on the first surface by using an anodic oxidation method;
Selectively removing the metal oxide film to form an opening;
Forming a solid electrolyte layer on the surface of the metal oxide film;
Forming a first extraction electrode that conducts to the first surface of the valve metal sheet body in the opening of the metal oxide film, and a second extraction electrode that contacts the surface of the solid electrolyte layer, respectively. The manufacturing method of the electrolytic capacitor sheet | seat characterized by these. A method for producing an electrolytic capacitor sheet, comprising:
Roughening the first and second surfaces of the valve metal sheet body;
Forming a metal oxide film on the first and second surfaces using an anodic oxidation method;
Selectively removing the metal oxide film formed on the first surface to form an opening;
Forming a solid electrolyte layer on the surface of the metal oxide film;
A first extraction electrode that conducts to the first surface of the valve metal sheet body within the opening of the metal oxide film; and a second extraction electrode that contacts the surface of the solid electrolyte layer formed on the first surface. And a step of forming a third extraction electrode in contact with the surface of the solid electrolyte layer formed on the second surface. The method of manufacturing an electrolytic capacitor sheet, comprising: A method of manufacturing a wiring board having an electrolytic capacitor sheet,
A step of producing an electrolytic capacitor sheet by the method according to claim 11;
A step of fixing a resin substrate having a window at a position corresponding to at least the first and second lead electrodes of the electrolytic capacitor sheet to the first surface, the resin substrate comprising a glass cloth, and
Forming a wiring connected to the first and second lead electrodes and extending on the surface of the resin substrate through the window. A method of manufacturing a wiring board having an electrolytic capacitor sheet,
Producing an electrolytic capacitor sheet by the method according to claim 12;
Fixing a first resin substrate made of a resin including glass cloth and having a window at a position corresponding to at least the first and second lead electrodes of the electrolytic capacitor sheet on the first surface of the electrolytic capacitor sheet; ,
Fixing a second resin substrate made of a resin containing glass cloth and having an electrode pad at a position corresponding to at least a third lead electrode of the electrolytic capacitor sheet on the second surface of the electrolytic capacitor sheet;
Forming a wiring connected to the first and second lead electrodes and extending on the surface of the first resin substrate through the window.

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