JP2007251101A - Circuit substrate with built-in solid electrolytic capacitor, interposer using it and package - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate with a built-in solid electrolytic capacitor which can achieve low resistance connection between an aluminum metallic layer which is an anode of the solid electrolytic capacitor and a through-hole. <P>SOLUTION: In the substrate with a built-in solid electrolytic capacitor, a sheet-like solid electrolytic capacitor consisting of an anode 1 of an aluminum metallic layer and a cathode 6 of a silver paste layer is built in an insulating resin 3. A front layer and a back layer are formed of a metallic layer 4. The anode 1 is connected to the metallic layer 4 of the front layer and the back layer via a through-hole 8. The cathode 6 is connected to the metallic layer 4 of the front layer by means of a conductor paste. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

  Noise countermeasures are becoming important as equipment increases in speed and frequency. When a semiconductor mounted on the surface of the interposer is switched at a high frequency, noise in the power supply system leaks to the outside. As a result, the IC chip mounted on the surface of the wiring board or the IC chip mounted on another wiring board on the mother board on which the wiring board itself is mounted may be affected, leading to a malfunction. A solid electrolytic capacitor that is surface-mounted on a mother board has terminal lengths and wiring lengths, and there is a limit to dealing with high speeds and high frequencies, so it is necessary to dispose a solid electrolytic capacitor inside the interposer.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
International Publication No. 03/107367 Pamphlet

  In the conventional solid electrolytic capacitor element, the connection to the anodized foil and the external electrode is generally performed by connecting to the lead frame by welding. When a connection method using welding connection or individual mounting is used for the solid electrolytic capacitor built-in substrate, it is necessary to provide a connection and mounting region, and there is a limit to downsizing. Therefore, as a method for forming anodized foil, a through-hole connection can be considered by forming a through hole in the substrate and plating. However, an oxide film is easily formed on the surface of aluminum. It was difficult to form a low resistance connection between the through hole and the through hole.

  The present invention solves the above-mentioned conventional problems, and an object thereof is to realize a circuit board with a built-in solid electrolytic capacitor in which aluminum and through holes are connected with low resistance.

  In order to achieve the above object, the present invention particularly includes a sheet-like solid electrolytic capacitor having an anode formed of an aluminum metal layer and a cathode formed of a silver paste layer in an insulating resin, and a surface layer and a back layer formed of a metal layer, The anode is connected to the surface and back metal layers through a through hole, and the cathode is connected to the surface metal layer by a conductive paste.

  According to the present invention, a sheet-like solid electrolytic capacitor in which the anode is made of an aluminum metal layer and the cathode is made of a silver paste layer is built in the insulating resin, the surface layer and the back layer are made of metal layers, and the anode is inserted through the through hole. The solid electrolytic capacitor element is connected to the front and back metal layers, and the cathode is connected to the front metal layer with a conductive paste. It can be electrically taken out to the outside of the substrate, and the end surface of the valve metal sheet inside the through hole has a configuration of a solid electrolytic capacitor built-in circuit board that penetrates the through hole through a nickel plating layer. The aluminum metal layer can be electrically connected to the copper plating layer without intervening the surface oxide film. Runode, a low resistance connection between the aluminum metal layer and the through-hole is an anode of a solid electrolytic capacitor can be realized.

(Embodiment 1)
Hereinafter, the solid electrolytic capacitor built-in circuit board according to the first embodiment of the present invention will be described with reference to the drawings. 1 is a cross-sectional view of a circuit board with a built-in solid electrolytic capacitor according to Embodiment 1 of the present invention, FIG. 2 is a cross-sectional view of the circuit board with a built-in solid electrolytic capacitor in the vicinity of a through hole 8, and FIG. It is an enlarged view in an electrolytic capacitor.

  In FIG. 1, a conductive polymer is formed so that a porous portion 2 in which one side of an anode 1 made of aluminum is made porous by chemical treatment as shown in FIG. 3 and the exposed portion of the porous portion 2 is covered. A solid electrolytic layer 5 as a layer is formed, and a cathode 6 made of an Ag paste layer is formed thereon. In the porous portion 2, a dielectric made of aluminum oxide 16 is formed on the surface of the anode 1, and the anode 1 and the solid electrolytic layer 5, and the anode 1 and the cathode 6 are electrically insulated, so that solid electrolysis A capacitor element is formed.

  This solid electrolytic capacitor is built in the insulating resin 3, the surface layer and the back layer are made of a metal layer 4 made of a wiring pattern, the anode 1 is connected to the surface layer and the back layer metal layer 4 through a through hole 8, and the cathode 6 Is connected to the metal layer 4 by a conductor 7.

  In the present embodiment, a conductor paste is used for the conductor 7. Further, in the present embodiment, the solid electrolytic capacitor is formed by having the porous portion 2 on one side of the anode 1, but is not limited to one side, and may be formed on both sides of the anode 1. Good. Further, in the present embodiment, the method for forming the solid electrolytic capacitor on one surface of the anode 1 is not particularly limited to the upward or downward direction.

  In the present invention, as long as the through hole 8 has a structure for connecting the front and back metal layers 4, the inside may be filled with an insulating resin, or may be filled with a metal or a mixture thereof.

  Here, FIG. 2 will be described. As shown in FIG. 2, in the vicinity of the end face of the anode 1 made of sheet-like aluminum, a connection made of a zinc layer 9, a nickel layer 10, a palladium layer 11, and a copper plating layer 12 covering the end face of the aluminum from the end face of the anode 1. It becomes the structure which has a layer. In addition, a connection layer including a palladium layer 11 and a copper plating layer 12 is formed on the end surface of the insulating resin 3. By using this configuration, a stable connection between aluminum and a copper through hole can be obtained.

  In the present embodiment, as the insulating resin 3, 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. In particular, a resin composition layer having a low dielectric constant can be obtained by using a fluororesin.

  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. In particular, 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, the filler may contain a dispersant, a colorant or a coupling agent. 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 insulating property of the resin composition layer can be improved.

  Further, the metal layer 4 of the surface layer and the back layer may be formed in advance by forming a wiring pattern on the surface of the circuit board by a transfer method and then forming a through hole, or the copper foil on the surface of the substrate may be patterned by etching after forming the through hole. . Furthermore, a nickel layer can be formed on the metal layer 4 on the front layer and the back layer of the substrate.

  As described above, according to the first embodiment, since the anode 1 is connected to the front and back metal layers 4 through the through holes 8, a stable electrical connection can be obtained by metal bonding. At the same time, local electrodes can be taken out through the through-holes 8, so that the substrate with a built-in solid electrolytic capacitor can be downsized and the degree of design freedom can be improved.

(Embodiment 2)
Next, a solid electrolytic capacitor built-in circuit board according to Embodiment 2 of the present invention will be described with reference to the drawings. 4 is a cross-sectional view of the circuit board with a built-in solid electrolytic capacitor in the second embodiment of the present invention, and FIG. 5 is an enlarged cross-sectional view in the vicinity of the through hole 8 of the circuit board with a built-in solid electrolytic capacitor in the second embodiment. In addition, about what has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In the second embodiment, the through hole 8 passes through the porous portion 2 in the anode 1. FIG. 5 is an enlarged view of the through hole 8 of the circuit board with a built-in solid electrolytic capacitor. Here, FIG. 6 is an enlarged view of the connecting portion between the anode 1 and the through hole 8. The porous portion 2 has a number of concave and convex shapes made of aluminum, and is filled with an insulator 13 made of a cured liquid resin. Thus, the reliability of the connection in the through hole 8 is improved by filling the porous portion 2 of aluminum with the insulator 13 and sealing the voids existing in the porous portion.

(Embodiment 3)
Next, a solid electrolytic capacitor built-in circuit board and an interposer using the same according to the third embodiment of the present invention will be described with reference to the drawings. 7 and 8 are interposers having a rewiring layer in a solid electrolytic capacitor built-in layer.

  In addition, about the thing which has the structure similar to the structure of Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  In this configuration, the rewiring layer may be formed by a build-up method using the circuit board with a solid electrolytic capacitor as a core layer, or the circuit board with a capacitor and the second wiring board are integrated using a prepreg filled with a conductive paste. May be used. In this embodiment, the rewiring layer is provided on both sides of the capacitor built-in layer. However, the rewiring layer is not limited to both sides of the capacitor built-in layer, and may be only on one side of the capacitor built-in layer. .

  By using this configuration, it is possible to deal with a rule of a narrow electrode interval of a semiconductor on the surface. With this configuration, since the distance from the semiconductor electrode terminal to the solid electrolytic capacitor can be shortened to the thickness direction of the substrate, an interposer substrate having an efficient semiconductor power supply stabilizing function and noise removing function can be obtained.

  Further, by incorporating a plurality of divided capacitor elements as shown in FIG. 7, an interposer corresponding to a semiconductor requiring multiple power supply voltages can be realized.

  Further, by forming a through hole independent from both electrodes of the capacitor element, a signal transmission wiring can be formed.

(Embodiment 4)
Next, a semiconductor package using the circuit board with a built-in solid electrolytic capacitor according to Embodiment 4 of the present invention will be described with reference to the drawings. 9 and 10 show a package in which a semiconductor is mounted on the surface layer of the circuit board with a built-in solid electrolytic capacitor according to the fourth embodiment. With this configuration, since the distance from the semiconductor electrode terminal to the solid electrolytic capacitor can be shortened to the thickness direction of the substrate, it is possible to efficiently stabilize the power supply of the semiconductor and remove noise. Furthermore, since noise countermeasures are taken inside the package, the noise countermeasure design required on each mother board on which the package is mounted can be reduced.

  Further, when the size of the semiconductor 14 to be mounted is smaller than the substrate size, a solid electrolytic capacitor is disposed in the center of the substrate and the signal line is disposed outside the substrate, thereby shortening the wiring from the semiconductor to the capacitor. Can do.

  As described above, the solid electrolytic capacitor built-in circuit board and the interposer and package using the same according to the present invention can be applied to the use of a circuit board on which a semiconductor in which noise countermeasures are important is 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 the same embodiment Sectional drawing of the element formation part of the circuit board with a built-in solid electrolytic capacitor in the same embodiment Sectional drawing of the solid electrolytic capacitor built-in circuit board in Embodiment 2 of this invention Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in the same embodiment Sectional drawing of the circuit board with a built-in solid electrolytic capacitor in the same embodiment 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 the same embodiment 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 the same embodiment

Explanation of symbols

1 Anode (aluminum)
DESCRIPTION OF SYMBOLS 2 Porous part 3 Insulating resin 4 Metal layer 5 Solid electrolytic layer 6 Cathode 7 Conductor 8 Through hole 9 Zinc layer 10 Nickel layer 11 Palladium layer 12 Copper plating layer 13 Insulator 14 Semiconductor 15 Bump 16 Aluminum oxide

Claims (13)

A solid electrolytic capacitor-embedded substrate in which an anode is an aluminum metal layer having a porous part and a cathode is a silver paste layer in which a sheet-like solid electrolytic capacitor is embedded in an insulating resin. A solid electrolytic capacitor built-in substrate, wherein the anode is connected to the surface layer and the back metal layer through a through hole, and the cathode is connected to the surface metal layer by a conductor. A zinc layer as a first layer and a nickel layer as a second layer are formed in this order on the cross section of the anode on the inner wall surface of the through hole, and a third layer is formed on the entire inner wall surface of the through hole including the second layer and the insulating resin layer. The substrate with a built-in solid electrolytic capacitor according to claim 1, wherein a palladium layer is formed, and further, an electrolytic copper plating layer is formed as a fourth layer on the inner wall surface, the surface layer, and the back layer of the through hole. The substrate with a built-in solid electrolytic capacitor according to claim 1, wherein the metal layer is a copper foil layer. The substrate with a built-in solid electrolytic capacitor according to claim 1, wherein the conductor is a cured conductive paste. 2. The solid electrolytic capacitor built-in circuit according to claim 1, further comprising a through hole penetrating an insulating layer in the substrate, wherein the through hole is insulated from a cathode and an anode of the solid electrolytic capacitor by the insulating layer. substrate. The board | substrate with a built-in solid electrolytic capacitor of Claim 2 by which the nickel layer is formed in the metal layer of the surface layer and back layer of a board | substrate. 2. The substrate with a built-in solid electrolytic capacitor according to claim 1, wherein a porous portion of the anode where no element is formed is filled with an insulator made of a cured liquid resin. The solid electrolytic capacitor built-in substrate according to claim 1, wherein the through hole is filled with an insulating resin. The solid electrolytic capacitor built-in substrate according to claim 1, wherein the through hole is filled with a metal or a mixture thereof. The interposer which has a rewiring layer in the board | substrate with a built-in solid electrolytic capacitor as described in any one of Claim 1 to 9. The interposer according to claim 10, which has a structure corresponding to a plurality of power terminals of a semiconductor from a solid electrolytic capacitor. 12. The interposer according to claim 11, wherein a plurality of solid electrolytic capacitors are incorporated, and the anodes are electrically separated from each other to correspond to independent power supply voltages. 13. A semiconductor package comprising a semiconductor element mounted on the interposer according to any one of claims 10 to 12.

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