JP2010171304A - Production method of component built-in substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production method of a component built-in substrate capable of forming an electrolytic capacitor part and a wiring pattern on an aluminum formation foil sheet, separately and independently, without deteriorating the electric characteristics of the capacitor. <P>SOLUTION: A separation-division groove 3 is formed on one surface of the aluminum formation foil by dry machining such as a laser apparatus and a metallic mold before forming the solid electrolytic capacitor 22 on the aluminum formation foil sheet, the solid electrolytic capacitor 22 is formed after forming a protective insulation material 4 on the same surface as a reinforcement material thereof, and the aluminum formation foil is ground from the back surface until the bottom of the groove 3 is exposed, and the solid electrolytic capacitor 22 and the wiring pattern 21 are formed on the aluminum foil sheet by electrically separating them in an independent manner. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a component-embedded board in which a capacitor is built in an arbitrary place of a printed circuit board.

  In recent years, LSIs used in electronic devices have been increased in speed and voltage. When the LSI operates at high speed, the power supply voltage is likely to fluctuate, voltage drop occurs due to the influence of wiring resistance, parasitic inductance, etc., and the semiconductor is likely to malfunction. Therefore, a capacitor is generally connected between the LSI power supply and the ground for the purpose of supplying a stable power supply and removing high-frequency noise from the semiconductor.

  In addition, with the increasing number of functions of electronic devices, LSIs that require a plurality of power supplies are increasing. For example, a digital circuit and an analog circuit are mixedly mounted. In such an LSI, a digital circuit power supply and an analog circuit power supply are separated, and a plurality of power supplies are supplied from the outside for each circuit, thereby reducing the influence of noise that the analog circuit receives from the digital circuit. Along with such a change in LSI, a circuit board on which an LSI is mounted is designed such that a power supply layer is separated into a plurality of power supplies having different voltages. Therefore, it is required that the power source and ground layer of the printed circuit board can be formed in a complicated shape like the wiring layer.

Against this background, a structure in which a capacitor is built in a printed circuit board has been developed in response to the demand for light and thin electronic devices (see Patent Document 1). In this patent, a core substrate made of a metal plate such as aluminum is processed using a drill or the like, the aluminum plate serves as an anode, the surface oxide (alumina) formed on the aluminum plate surface serves as a dielectric, and serves as a cathode. There has been proposed a printed wiring board in which a capacitor is formed and built in between a conductor layer. However, in the above proposal, in the method of forming a capacitor between the conductor layer and the aluminum plate described above, the aluminum plate serving as the anode cannot be divided, so that the entire aluminum plate has the same potential. Therefore, there is a problem that a capacitor can be formed only between one power supply and GND, and cannot be applied to an LSI having a plurality of power supplies, and a method of electrically dividing a capacitor portion by wet etching an aluminum plate in a photolithography process Has also been considered. Here, the problem of the photolithography process of the solid electrolytic capacitor using the aluminum formed foil capable of obtaining a high capacity as an aluminum plate as a conventional construction method will be described with reference to FIG. FIGS. 8A to 8E are cross-sectional views of a photoetching process which is a wet process using an aluminum conversion foil on one side and a photoresist material. Aluminum conversion foil is an aluminum metal foil that is electrochemically roughened, has a surface area of several hundred times or more, and an aluminum oxide film serving as a dielectric is formed on its surface to produce an electrochemically dense film. As shown in FIG. 8 (a), it is divided into two portions of the aluminum metal foil plate and the portion where the porous portion 1 is formed. Next, as shown in FIG. 8B, a photoresist 81 is formed on the porous portion 1 of the aluminum chemical conversion foil. Next, as shown in FIG. 8C, a photoresist pattern 82 is formed by exposing the photoresist 81 using a photomask designed to form a desired capacitor shape and wiring pattern at an arbitrary position. . Next, as shown in FIG. 8D, the aluminum chemical conversion foil is wet etched into a desired pattern using a commercially available mixed acid etching solution or the like. Next, as shown in FIG. 8E, by removing the photoresist pattern 82 with an organic solvent such as DEMSO or NMP, the groove 83 can be processed into a desired pattern shape. In FIGS. 8A to 8E, etching is performed from the aluminum chemical conversion foil. However, it is possible to divide by performing photo-etching in the same position as the groove 83 from the plate 2 portion. However, if etching is performed on both sides, it will be separated and dropped at the part patterned from the sheet form of aluminum conversion foil, so after etching one side, individual pieces such as support sheets for preventing separation and separation on the etched surface It is necessary to paste something that can be fixed. The problems of the wet etching process will be described. In FIG. 8B, the photolithography resist 81 needs to be sufficiently filled in the porous layer of the porous portion 1 of the aluminum conversion foil, but the photoresist 81 is removed in the step of FIG. 8E. Since the photoresist 81 that has penetrated into the porous portion 1 of the aluminum conversion foil is very difficult to remove, it becomes a residue in the porous portion 1 of the photoresist 81. Further, when an organic solvent to which an alkaline material that can easily remove the photoresist 81 is used is used, the residue of the photoresist 81 can be easily removed, but the thin alumina dielectric that is the surface oxide of the porous portion 1 of the aluminum conversion foil is damaged. There is a possibility that electrical characteristics such as deterioration of insulation resistance may be deteriorated, and there is a concern that it takes a very long time and effort to solve these problems.
JP 2004-31641 A

  However, as a method for electrically independent division of the capacitor portion of the aluminum plate, when patterning is performed using a wet etching process, it is formed on the surface of the aluminum plate that affects the electrical characteristics of the capacitor by the solution used in the process. There is a concern that the formed aluminum oxide film may be adversely affected, and problems such as the need for a step of protecting the porous portion of the aluminum formed foil that hits the capacitor portion arises in order to prevent deterioration of the capacitor characteristics.

  The present invention has been conceived under such a problem, and as a means for dividing the aluminum formed foil into a capacitor and a wiring pattern in a desired arbitrary location and shape, the capacitor portion before and after the formation of the capacitor. A cutting process that does not use a process that uses a solution that may deteriorate characteristics, and a state in which it can be conveyed in the form of a sheet from the beginning to the end of the process so that the separated pieces do not fall off when the aluminum conversion foil is separated and divided By combining the processes that can be manufactured in the process, capacitors and wiring patterns using aluminum foil can be formed in any location at a desired size, and at the same time, a component-embedded board with a built-in capacitor having good electrical characteristics is formed. The purpose is that.

  In order to achieve the above object, the present invention provides a sheet state by pre-grooving a formed aluminum foil without completely cutting a desired capacitor division pattern using a dry processing facility such as a laser or a mold. Fill the groove part with protective insulating resin material in the part and groove part except the part where the desired capacitor is formed and the electrical extraction part of the wiring pattern on the grooved surface of the aluminum conversion foil. The protective insulating resin material is reinforced to prevent the aluminum conversion foil sheet from falling off, and the surface opposite to the groove processing surface of the aluminum conversion foil is gradually scraped with a device such as a buffing machine, and processed by the dry processing equipment. The resin filled in the groove is exposed and scraped until the divided portions of the aluminum formed foil are electrically separated.

  As described above, the component-embedded substrate of the present invention uses a solution that degrades the capacitor characteristics of the aluminum formed foil in the wet etching process, etc., by dividing the aluminum foil one side at a time by dry grooving and buffing. In addition, an electrically divided capacitor and a wiring pattern can be formed at an arbitrary position and shape, and a printed circuit board with a built-in capacitor having good characteristics can be easily manufactured. .

(Embodiment 1)
Hereinafter, the first aspect of the present invention will be described with reference to the drawings, particularly according to the first, seventh and eighth aspects of the present invention.

  FIG. 1 shows a manufacturing process of a capacitor built-in sheet in which a capacitor portion and a wiring portion are separately formed using the aluminum formed foil sheet according to the first embodiment.

  In FIG. 1A, the aluminum chemical conversion foil is composed of a porous portion 1 and a plate portion 2. The configuration of the aluminum chemical conversion foil may be that of the porous portion 1 on both sides of the plate portion 2. The porous portion 1 of the aluminum chemical conversion foil is roughened by electrochemically etching an aluminum plate (having a general thickness of 40 μm or more and 150 μm or less) to increase the surface area of the aluminum surface to several hundred times. Forming part. Further, the aluminum chemical conversion foil further electrochemically forms a dense oxide film layer serving as a dielectric on the aluminum surface. With the plate portion 2 of the porous portion 1 of the aluminum formed foil as the capacitor portion as an anode, aluminum and a dense oxide film serving as a dielectric on the surface, and a conductive polymer shown in FIG. Using the material 5 as a cathode portion, a capacitor having a high capacity and good electrical characteristics is formed.

  Next, in FIG. 1B, a groove 3 is formed in the divided portion so that a desired capacitor pattern and wiring pattern can be formed from the surface of the porous portion 1 of the aluminum chemical conversion foil. The depth of the groove 3 is set to a portion where the total thickness of the porous portion 1 of the aluminum chemical conversion foil and a part of the thickness of the plate portion 2 are left. As a method of processing the groove 3 in the aluminum chemical conversion foil, the dielectric film formed on the porous portion 1 of the aluminum chemical conversion foil is subjected to mechanical damage such as deficiency or deformation, or chemical damage to the surface or chemical deterioration. It is important not to give. In addition, it is necessary to prevent adverse effects from residues such as water-soluble rust preventive materials used during processing. Therefore, it is desirable to use a dry processing method such as laser processing and die processing as a method of processing the aluminum chemical conversion foil. Moreover, it is desirable that the cooling cleaning water used in a grinding machine capable of grooving while rotating the bit or a dicing apparatus capable of grooving while rotating by rotating a disk-shaped grindstone is pure water. Etching with a mixed acid of an aluminum material using a photoresist is also possible, but damage to the dielectric film formed on the porous portion 1 of the aluminum conversion foil as a capacitor portion by an etching solution or a material for removing the photoresist material is possible. There is a concern that it takes a lot of time to select a material that avoids the problem.

  Here, a laser apparatus will be described as a method for processing the groove 3 of the aluminum chemical conversion foil. When using a YAG laser, the pulse is a Q-switch type pulse wave, the frequency is low, the output of one pulse is increased, and the same part is irradiated two or more times with respect to the groove depth, The groove depth can be easily adjusted. In particular, those using a marker YAG laser or an engraving YAG laser can obtain a good groove shape. In an excimer laser, a very clean groove processing is possible without seeing a volume rising portion of a laser removal product generated around a laser groove called RIM, but the processing time is long. In the carbon dioxide laser device, the absorption efficiency of aluminum is lower than that of the YAG laser.

  Moreover, the method of using a metal mold | die as a processing method of the groove | channel 3 of aluminum conversion foil is demonstrated. The sharp angle of the blade used in the mold can form a groove with less taper, but the surface of the aluminum conversion foil is a hard film of aluminum oxide, and the blade is easy to spill. It is necessary to adjust the angle of the blade to an angle at which the blade does not easily spill.

  The thickness excluding the groove portion of the plate portion 2 of the aluminum chemical conversion foil is such that it is divided into pieces at the groove portion 3 of the aluminum chemical conversion foil and does not fall off during handling in a later step. The thickness of the porous portion 1 of the aluminum chemical conversion foil is generally 10 μm or more and 50 μm or less. The plate part 2 is 10 μm or more and 50 μm or less. The ratio of the depth of the groove 3 of the plate portion 2 is desirably 10 μm or more depending on the electrical characteristics such as ESR of the capacitor.

  Next, in FIG. 1C, a protective insulating material 4 is formed in addition to the groove 3 and the capacitor forming portion of the grooved aluminum formed foil. As the protective insulating material, a wet process such as a screen printer, a dispenser, or an ink jet is used after the paste is formed. In the present invention, the protective insulating material 4 is formed by screen printing. In addition, it is desirable that the protective insulating material 4 subjected to the screen printing penetrates from the minute holes of the porous portion 1 of the aluminum conversion foil and coats the entire dielectric surface so that the porous portion 1 does not have a cavity. The viscosity of the paste for screen printing is 120 Pa · s (B-type viscometer 10 rpm), which is lower than that generally used to increase the permeability of the paste, and the porous portion of the aluminum formed foil A range in which the spread width of paste at the time of printing one via window does not exceed 50 μm is desirable. Further, a screen mesh having a size of 120 to 400 mesh is used depending on the size and pattern accuracy of an arbitrary shape of the capacitor. However, when the mesh becomes high, the printing amount of the paste is reduced, so that it is necessary to repeatedly print a large number of times.

  In FIG. 1 (d), a conductive polymer material 5 is formed on the porous portion 1 of the aluminum chemical conversion foil and then on the capacitor forming portion of the aluminum chemical conversion foil.

  The solid electrolytic capacitor formed on the aluminum chemical conversion foil has the aluminum portion of the aluminum chemical conversion foil as an anode, and a solid electrolyte layer made of the conductive polymer material 5 on the surface thereof through a dielectric film made of an aluminum oxide film. It is formed as. This solid electrolyte layer is formed by forming a functional polymer layer such as polypyrrole, polythiophene, or polyaniline by chemical polymerization or electrolytic polymerization, or by impregnating a manganese nitrate solution and thermally decomposing it to form a manganese dioxide layer. Obtainable.

  Further, in FIG. 1 (e), carbon paste 6 is applied to the conductive polymer 5 serving as a solid electrolyte layer as an electrical extraction part of a cathode by a coating machine such as screen printing, a dispenser or an inkjet. The polymer material 5 is formed so as to cover it.

  Further, in FIG. 1 (f), a conductive paste 7 such as an Ag paste is formed by using a carbon paste 6 by screen coating, a dispenser, an ink jet or other coating machine. This structure facilitates the extraction of the electrode from the capacitor portion.

  Next, in FIG. 1 (g), the surface is gradually removed from the rear surface of the processed surface of the groove 3 of the aluminum conversion foil, and the aluminum conversion is performed up to the bottom of the groove 3 of the protective insulating layer filled in the groove 3. The surface of the foil is removed and divided into desired capacitor portions and wiring patterns of the aluminum chemical conversion foil to ensure electrical insulation. As a method for removing the surface layer of the aluminum conversion foil, mechanical polishing such as a roll-type buff polishing apparatus, rotary polishing or a parallel polishing machine, and chemical etching of the aluminum conversion foil with a mixed acid etching solution are also possible. However, in the rotary buffing machine, pure water can be used as a polishing powder cleaning liquid to be used rather than chemical etching using a mixed acid solution, and in a polishing experiment with a workpiece size of about 500 mm □, a 4-axis rotary buffing machine is used. By using two buffing roller shafts such as polishing roughness 200 # to 300 # and 300 to 400 #, it is advantageous to polish at a high speed about 2 to 5 times that of chemical etching. . In particular, it is desirable not to apply a mechanical load such as elongation or deformation that affects the electrical characteristics of the capacitor portion formed on the aluminum conversion foil.

  Next, in FIG. 1 (h), in order to facilitate connection of the exposed portion of the aluminized plate portion 2 to the exposed portion of the aluminized plate portion 2 from which the surface of the plate portion 2 of the aluminum formed foil is removed, A metal film 8 is formed by screen printing, a dispenser or an ink jet apparatus using a paste of nickel plating or conductive material having good electrical connection with aluminum. Moreover, you may use the electrically conductive paste containing the metal nanoparticle which can be formed at low temperature. Alternatively, an alloy made of copper, zinc, or the like having good electrical connectivity of aluminum may be formed by thermal spraying.

  Next, in FIG. 1I, another metal film 9 is formed on the metal film 8 by a corrosion preventing material such as gold plating. When the metal film 8 has no problem such as alteration, the metal film 9 is unnecessary.

  Through the above steps, a sheet-like product in which desired capacitors and wiring patterns are separated and divided can be formed by the aluminum chemical conversion foil.

  In the present invention, the structure of the solid electrolytic capacitor built-in sheet using the aluminum chemical conversion foil and the materials used will be described with reference to FIG. The aluminum chemical conversion foil can form a porous portion by electrochemically etching the surface of the aluminum metal foil on one or both sides with acid or the like. The aluminum chemical conversion foil has a porous portion 1 that forms a porous portion 1 on the surface of an aluminum metal foil and a plate portion 2 that is not etched. By forming a thin aluminum oxide layer on the aluminum chemical conversion foil and further forming a porous portion, the area that functions as a solid electrolytic capacitor is expanded, and a large capacitance can be obtained.

  By the groove 3 of the aluminum chemical conversion foil, it can be formed in a desired configuration like the wiring pattern 21 and the solid electrolytic capacitor 22 of FIG.

  Next, the protective insulating layer 4 uses a resin insulating material or an inorganic insulating material. As the resin insulating material, epoxy resin, phenol resin, or polyimide resin is used. As the inorganic insulating material, a material that can be fired at a peak temperature of about 600 ° C. or lower in an oxidizing atmosphere and at a peak temperature of 800 ° C. or lower in nitrogen atmosphere firing is used because of the heat resistance of the aluminum conversion foil.

  When a mixture of filler and insulating resin is used as the protective insulating layer 4 in the resin insulating material, by selecting the filler and the insulating resin, the elastic modulus, thermal expansion coefficient, thermal conductivity of the protective insulating layer 4 are selected. The degree, dielectric constant, etc. can be easily controlled. For example, alumina, magnesia, boron nitride, aluminum nitride, silicon nitride, polytetrafluoroethylene, silica, etc. can be used as the filler. By using alumina, boron nitride, aluminum nitride, heat is increased from the conventional glass-epoxy substrate. A substrate with high conductivity can be manufactured, and the heat dissipation characteristics of the composite wiring substrate can be improved. Alumina also has the advantage of low cost. When silica is used, the protective insulating layer 4 having a low dielectric constant can be obtained, and the specific gravity is light. Therefore, it is preferable for high frequency applications such as cellular phones. Even if silicon nitride or polytetrafluoroethylene, for example, “Teflon (registered trademark)” (DuPont) is used, an electrically insulating layer having a low dielectric constant can be formed. Moreover, the thermal expansion coefficient can be reduced by using boron nitride. The elastic modulus can be adjusted by the filler content, whereby the warp of the circuit board can be controlled.

  The protective insulating material 4 may further contain a dispersant and a coupling agent. The filler in the insulating resin can be dispersed with good uniformity by the dispersant. Since the coupling agent can increase the adhesive strength between the insulating resin and the filler, the insulating property of the electrically insulating substrate can be improved.

  Further, the shape of the solid aluminum electrolytic capacitor 22 can be stabilized and controlled by controlling the thickness of the protective insulating layer 4. By forming the solid electrolytic capacitor 22 with high thickness accuracy, it is easy to incorporate it in the substrate.

  Next, the conductive polymer 5 will be described in order to form the aluminum electrolytic foil solid electrolytic capacitor 22. The solid electrolytic capacitor 22 formed on the aluminum chemical conversion foil has an aluminum portion of the aluminum chemical conversion foil as an anode and a solid electrolyte layer made of the conductive polymer 5 on the surface of the aluminum electrolytic foil through a dielectric film made of an aluminum oxide film. It is formed as. This solid electrolyte layer is formed by forming a functional polymer layer such as polypyrrole, polythiophene, or polyaniline by chemical polymerization or electrolytic polymerization, or by impregnating a manganese nitrate solution and thermally decomposing it to form a manganese dioxide layer. Obtainable. Since it has a high dielectric constant, it is advantageous as the solid electrolytic capacitor 22. Further, a carbon paste 6 is formed on the conductive polymer 5 serving as a solid electrolyte layer as an electrical extraction part of the cathode, and a conductive paste 7 such as an Ag paste is formed. This structure facilitates the extraction of the electrode from the capacitor. Further, as the electrical extraction part of the anode part of the solid electrolytic capacitor 22, the metal film 8 uses a plating such as nickel plating having good connectivity with aluminum or a conductive paste for connecting an aluminum electrode. In addition, when the metal film 9 is formed by gold plating or the like, the electrical characteristics of the capacitor are stabilized when the metal film 8 is easily oxidized in the atmosphere such as nickel plating and difficult to be electrically extracted.

  As described above, by using a mechanical processing method that does not use a wet etching process as a method for forming the independent solid electrolytic capacitor 22 or the wiring pattern 21 having the desired shape of the aluminum chemical conversion foil sheet, In addition, a sheet incorporating the solid electrolytic capacitor 22 and the wiring pattern 21 having excellent electrical characteristics can be easily formed. Further, the separate and built-in capacitor built-in sheet can be used as a multiple capacitor component and can be built into the printed circuit board of the present invention. Moreover, although this Embodiment described aluminum conversion foil, the same effect can be acquired by the same method also about the tantalum capacitor using a tantalum foil.

(Embodiment 2)
Hereinafter, the second aspect of the present invention will be described with reference to the drawings. In addition, the code | symbol of FIG. 1 which is explanatory drawing of Embodiment 1 is the same.

  FIG. 3 shows a state of the aluminum chemical conversion foil in the first embodiment, in which the porous portion 1 is formed on both surfaces of the plate portion 2 by double-side acid etching. The depth of the groove 3 of the aluminum chemical conversion foil is divided into pieces when handling in the subsequent process, and the thickness of the plate portion 2 that does not fall off is reinforced by the porous portion 1 opposite to the groove 3. Therefore, the thickness of the plate part 2 of the aluminum chemical conversion foil after removal can be increased in the surface removal process from the back surface in the subsequent process, and the ESR which is the electrical characteristic after the formation of the solid electrolytic capacitor of the aluminum chemical conversion foil can be obtained. There is an effect to lower. According to the above invention, the electrical characteristics of the capacitor built-in sheet according to claim 1 can be easily improved.

(Embodiment 3)
Hereinafter, the third embodiment of the present invention will be described with reference to the drawings. In addition, about the structure same as Embodiment 1-3, the same number is provided and the description is abbreviate | omitted.

  FIG. 4 is a cross-sectional view of the printed circuit board manufacturing process according to the first embodiment. FIG. 4 shows a step in place of the part corresponding to (b) of the manufacturing process of FIG. 1, and is shown by (b) and (c) in FIG. (A) of FIG. 4 is the same as that of Embodiment 1 and is a state of an aluminum conversion foil, in which the porous portion 1 is formed on both surfaces of the plate portion 2 by double-sided acid etching on at least one surface. . The porous portion 1 may be formed only on one side forming the capacitor. Next, in FIG. 4 (b), from the sheet form of the aluminum conversion foil after the groove processing of the next process to the aluminum conversion foil provided with the porous part 1 and the plate part 2 in advance by the transport load at the handling of the subsequent process. For the purpose of supporting so as not to divide and fall off, a heat-resistant base material 41 is pasted on the opposite side of the aluminum electrolytic foil from the surface on which the solid electrolytic capacitor is formed. The heat-resistant base material 41 is made of a material that can withstand the heat history of the subsequent process. Next, in FIG. 4C, the depth of the groove 3 of the aluminum chemical conversion foil is determined by the thickness of the porous part 1 on the capacitor forming surface of the aluminum chemical conversion foil and the thickness of the plate part 2 necessary for the electrical characteristics of the capacitor. The remaining groove is the minimum groove depth, and the maximum groove depth is possible until the aluminum formed foil can be divided. Moreover, you may groove-process to a part of heat-resistant base material 41 within the range which does not divide | omit and drop | separate of a sheet | seat for the handling of a post process. In the present embodiment, the heat-resistant base material 41 is preliminarily fixed to the aluminum conversion foil so as not to fall off during handling in the subsequent process, and the process shown in FIG. 1 (c) shown in the first embodiment. Then, by forming the protective insulating material 4 from the grooved surface, the protective insulating material 4 has an effect of preventing the aluminum formed foil from being separated and removed, so that the heat-resistant substrate 41 becomes unnecessary, and the aluminum It becomes possible to remove from the conversion foil. By this method, when the groove of the aluminum chemical conversion foil is processed, the aluminum chemical conversion foil can be processed to the depth of the groove as much as the thickness of the aluminum chemical conversion foil as compared with the first and second embodiments. Thus, the thickness of the plate portion 2 of the aluminum chemical conversion foil after the removal can be increased in the surface removal step, and there is an effect of lowering the ESR which is an electrical characteristic after the formation of the solid electrolytic capacitor of the aluminum chemical conversion foil. Further, when the groove is processed to have a thickness equal to or greater than the thickness of the aluminum chemical conversion foil, it is possible to omit the back surface polishing of the aluminum chemical conversion foil on the capacitor forming surface in (g) of the first embodiment.

(Embodiment 4)
Hereinafter, the fourth embodiment of the present invention will be described with reference to the drawings. In addition, about the structure same as Embodiment 1-3, the same number is provided and the description is abbreviate | omitted. FIG. 5 is a cross-sectional view of the printed circuit board according to the first embodiment. 5 (a) and 5 (b) show an electrical extraction electrode on the capacitor portion and the wiring pattern formed of the aluminum chemical conversion foil in the steps (c) to (f) of FIG. 1 of the first embodiment. The method of forming is shown.

  In FIG. 5 (a), a protective material via is previously used as a capacitor outlet in the portion where the electrode for electrical extraction is formed in the step of forming the protective resin material 4 of FIG. 1 (c) shown in the first embodiment. A protective material via hole 52 is provided as a hole 51 and a wiring pattern outlet. Next, as shown in FIG. 5B, a conductive adhesive 53 and a conductive adhesive 54 are formed in each via hole. The conductive adhesive may be formed by plating other than using a conductive paste.

(Embodiment 5)
The fifth embodiment of the present invention will be described below with reference to the drawings. In addition, about the same structure as Embodiment 1-4, the same number is provided and the description is abbreviate | omitted. FIG. 6 is a cross-sectional view of the printed circuit board according to the first embodiment. 6 (a) and 6 (b) correspond to the steps of FIGS. 5 (a) and 5 (b) of the fifth embodiment, and the capacitor portion and the wiring pattern formed of the aluminum formed foil are electrically connected. In the method of forming the extraction electrode, holes are formed in advance in the portion of the aluminum formed foil where the extraction electrode is to be formed to improve electrical connectivity.

  In FIG. 6A, in the process of either FIG. 1B or FIG. 1C shown in the first embodiment, a wiring pattern take-out is previously used as a capacitor take-out port in a portion where an electrode for electric take-out is formed. In the formation of the protective material 4 at the mouth, through holes 63 and 64 are formed by forming protective via holes 61 and via holes 62 and drilling at the respective positions. Next, as shown in FIG. 6B, a conductive adhesive 65 and a conductive adhesive 66 are formed in each via hole. The conductive adhesive may be formed by plating other than using a conductive paste.

(Embodiment 6)
Hereinafter, the sixth embodiment of the present invention will be described with reference to the drawings. In addition, about the same structure as Embodiment 1-5, the same number is provided and the description is abbreviate | omitted. FIG. 7 is a cross-sectional view of the printed circuit board according to the first embodiment. FIG. 7 relates to a method of manufacturing a printed circuit board using a sheet provided with a desired divided and independent solid electrolytic capacitor portion 22, wiring pattern 21, and electrical connection portion in the aluminum chemical conversion foil sheets of Embodiments 1 to 5. It is.

  In FIG. 7, the circuit board is composed of an electrically insulating base 71 and a plurality of wiring patterns 74 formed on the electrically insulating base 71, and at least one layer is formed of an aluminum conversion foil composed of the porous portion 1 and the plate portion 2. The wiring layer 21, the solid aluminum electrolytic capacitor 22 formed on a part of the wiring layer 21 made of an aluminum chemical conversion foil, the solid aluminum electrolytic capacitor 22 formed on the electrically insulating base 71, the wiring pattern 21, and the wiring pattern 76. Vias 73 for electrically connecting the two. The manufacturing method of this invention is demonstrated using FIG.

  FIG. 7A shows an electrically insulating substrate 71.

  Next, as shown in FIG. 7B, a through-hole 72 is formed in the electrically insulating substrate 71 using a laser, a punching device or a mold. In forming the through hole 72, a carbon dioxide laser, YAG laser, or excimer laser is used as a light source for laser processing. In laser processing, small-diameter through holes can be formed in a short time, and processing with excellent productivity can be realized. Further, in the via 73 of FIG. 7, an inner via is taken as an example, but interlayer connection may be performed by a through hole. For example, a through hole formed by plating using gold, silver, copper, nickel, or the like after the through hole is formed may be used. The through-holes may be formed by punching or drilling. When drilling or punching is used, it can be formed by existing versatile equipment.

  Next, as shown in FIG. 7C, vias 73 and 77 are formed in the through holes 72 in an uncured state using a conductive paste.

  Next, as shown in FIG. 7 (d), a metal foil such as Cu serving as the wiring layer 74 can be temporarily bonded to the electrically insulating substrate 71 formed with the via 73 in an uncured state of the electrically insulating substrate 71. Temporary lamination is performed in a heating and pressurizing process under conditions.

  Next, as shown in FIG. 7 (e), a solid electrolytic capacitor 22 and a wiring pattern 21 formed in an arbitrary place in a desired pattern size are provided on the aluminum chemical conversion foil sheet formed using the first to fifth embodiments. Prepare the prepared sheet.

  Next, as shown in FIG. 7 (f), the electrically insulating substrate 71 provided with the via 73 and the wiring layer 74 formed in FIG. 7 (d), and the solid electrolytic capacitor 22 prepared in FIG. 7 (e), Electrical connection is also made by stacking and integrating the sheet containing the wiring pattern 21 in a heating and pressurizing process and then curing the sheet. The connection between the conductor paste 7 serving as the electrical extraction portion on the cathode side of the solid electrolytic capacitor 22 and the via 73 of the electrically insulating base 71 is performed during the main curing. In addition, connection of the conductive adhesive 54 that is an electrical extraction portion of the wiring pattern 21 on the aluminum formed foil sheet side is also performed during the main curing.

  Next, in FIG. 7G, a wiring pattern 76 is formed by a photolithography process of the aluminum chemical conversion foil sheet containing the integrated solid electrolytic capacitor 22 and the wiring layer 74 of the electrically insulating base material 71.

  Next, in FIG. 7 (h), the aluminum chemical conversion foil sheet incorporating the solid electrolytic capacitor 22 and the electrically insulating base material 71 are integrated with each other by (a) to (d) of FIG. The electrically insulative base material 71 on which the formed via 77 and the wiring layer 74 are formed is laminated and integrated on one side or both sides by a heating and pressurizing step, and is electrically cured by performing main curing. The connection between the metal film 9 serving as the electrical extraction portion on the anode side of the solid electrolytic capacitor 22 and the via 77 of the electrically insulating base 71 is performed during the main curing. Moreover, the connection of the metal film 9 which is the electrical extraction part of the wiring pattern 21 on the aluminum formed foil sheet side is also performed during the main curing.

  Next, as shown in FIG. 7 (i), a desired wiring pattern 78 or land pattern is formed on the wiring layer 74 formed on the electrically insulating substrate 71 integrally formed on one or both sides by a photolithography process. 79 can be formed.

  By the above manufacturing method, a printed circuit board having a built-in aluminum electrolytic foil and a solid electrolytic capacitor 22 having good electrical characteristics and a wiring layer pattern 21 can be easily formed.

  Next, materials used in the present invention will be described. In the present invention, the electrically insulating substrate 71 can be made of an insulating resin, a mixture of filler and insulating resin, or the like. There may also be reinforcing materials such as glass cloth. As the insulating resin, a thermosetting resin, a thermoplastic resin, a photocurable resin, or the like can be used. By using an epoxy resin, a phenol resin, or an isocyanate resin having high heat resistance, the electrically insulating substrate 71 can be used. The heat resistance can be increased. In addition, a fluororesin having a low dielectric loss tangent, for example, polytetrafluoroethylene (PTFE resin), PPO (polyphenylene oxide) resin (also referred to as PPE (polyphenylene ether) resin), a resin containing a liquid crystal polymer or a resin obtained by modifying these resins is used. As a result, the high frequency characteristics of the electrically insulating substrate 71 are improved.

  When a mixture of filler and insulating resin is used as the electrically insulating base 71, the elastic modulus, thermal expansion coefficient, thermal conductivity, dielectric of the electrically insulating base 71 is selected by selecting the filler and the insulating resin. The rate and the like can be easily controlled. For example, alumina, magnesia, boron nitride, aluminum nitride, silicon nitride, polytetrafluoroethylene, silica, or the like can be used as the filler. By using alumina, boron nitride, or aluminum nitride, a substrate having higher thermal conductivity than that of a conventional glass-epoxy substrate can be manufactured, and heat dissipation characteristics of the composite wiring substrate can be improved. Alumina also has the advantage of low cost. When silica is used, an electrically insulating base material 71 having a low dielectric constant is obtained, and the specific gravity is light. Therefore, it is preferable for high-frequency applications such as cellular phones. Even if silicon nitride or polytetrafluoroethylene, for example, “Teflon (registered trademark)” (DuPont) is used, an electrically insulating layer having a low dielectric constant can be formed. Moreover, the thermal expansion coefficient can be reduced by using boron nitride. The elastic modulus can be adjusted by the filler content, whereby the warp of the circuit board can be controlled.

  The electrically insulating substrate 71 may further contain a dispersant and a coupling agent. The filler in the insulating resin can be dispersed with good uniformity by the dispersant. Since the coupling agent can increase the adhesive strength between the insulating resin and the filler, the insulating property of the electrically insulating substrate can be improved.

  Further, the shape of the solid aluminum electrolytic capacitor can be stabilized and controlled by controlling the thickness of the electrically insulating substrate 71. By forming the aluminum solid electrolytic capacitor 22 with high thickness accuracy, it is easy to incorporate it in the substrate.

  The vias 73 and 77 are made of a conductive paste such as Ag. By forming the surfaces of the electrolytic capacitor 22 and the wiring pattern 21 connected to the via 73 with gold, silver, copper, nickel, solder, tin, or the like by plating or the like, the connection resistance with the via is stabilized.

  The vias 73 and 77 can be filled vias by plating, and are preferably formed from one or more materials selected from gold, silver, copper, solder, nickel, and tin. Further, a plating layer may be formed in the via hole, and further filled with resin, or may be formed by a build-up via.

  The wiring layer 74 uses a metal foil sheet having good conductivity such as Cu. The wiring patterns 76 and 78 formed by photolithography of the wiring layer 74 can improve corrosion resistance and electrical conductivity by plating the surface. Moreover, the adhesiveness with the electrical insulating base material 71 can be improved by roughening the contact surface of the wiring pattern 76 with the electrical insulating base material 71. Examples of the roughening treatment include dry etching using a reactive gas, machining by sandblasting, and electrolytic etching.

  Further, by using a conductive resin composition as the wiring patterns 76 and 78, it is possible to manufacture a wiring pattern by screen printing or the like. Furthermore, by using a lead frame, a metal having a low electric resistance and a large thickness can be used. Further, a simple manufacturing method such as fine patterning by etching or punching can be used.

  Moreover, about the sheet | seat which isolate | separated and divided the desired electrolytic capacitor 22 and wiring pattern which were formed in the aluminum chemical conversion foil sheet | seat shown in FIG.7 (e) is a thing of Embodiment 1-5, description is abbreviate | omitted However, the electrical connection between this layer and the other wiring pattern 76 is vias 73 filled in the through holes 72 formed in the electrically insulating base material 71.

  As described above, according to the present embodiment, by using an aluminum foil, a capacitor can be formed at an arbitrary position and shape on a substrate, and a large-capacity capacitor is built in without increasing the thickness of the substrate. Thus, a circuit board can be provided.

  The circuit board of the present invention can form a large-capacitance capacitor at an arbitrary position / location on the circuit board, and is useful as a circuit board having noise countermeasures. Further, it is useful as a substrate with a built-in capacitor corresponding to an LSI that generates switching noise due to high-speed operation or an LSI that includes a plurality of power supplies.

(A)-(i) is process sectional drawing which shows the manufacturing method of the capacitor | condenser and wiring pattern built-in sheet in Embodiment 1, 2 of this invention Sectional drawing of the capacitor | condenser and wiring pattern built-in sheet | seat in Embodiment 1 of this invention (A)-(b) is sectional drawing of the manufacturing method of the capacitor | condenser and wiring pattern built-in sheet | seat in Embodiment 2 of this invention (A)-(c) is sectional drawing of the manufacturing method of the capacitor | condenser and wiring pattern built-in sheet in Embodiment 3 of this invention (A)-(b) is manufacturing method process sectional drawing of the capacitor | condenser and wiring pattern built-in sheet in Embodiment 4 of this invention (A)-(b) is manufacturing method process sectional drawing of the capacitor | condenser and wiring pattern built-in sheet in Embodiment 5 of this invention (A)-(i) is process sectional drawing which shows the printed circuit board using the capacitor | condenser of Embodiment 1-5 of this invention, and a wiring pattern built-in sheet | seat, and its manufacturing method (A)-(e) is process sectional drawing which shows the subject of the manufacturing method of the conventional capacitor | condenser and a wiring pattern built-in sheet | seat

DESCRIPTION OF SYMBOLS 1 Porous part of aluminum conversion foil 2 Plate part of aluminum conversion foil 3 Groove 4 Insulating material for protection 5 Conductive polymer material 6 Carbon paste 7 Conductive paste 8 Metal film 9 Metal film 21 Wiring part 22 Capacitor formation part 41 Heat-resistant substrate 51, 52 Via hole 53, 54 Conductive adhesive 61, 62 Via hole 63, 64 Through hole 65, 66 Conductive adhesive 71 Electrical insulating substrate 72 Through hole 73 Via 74 Wiring layer 75 Conductivity Adhesive 76 Wiring pattern 77 Via conductor 78 Wiring pattern 81 Photo resist 82 Photo resist pattern 83 Groove

Claims (8)

In a component-embedded substrate in which an aluminum solid electrolytic capacitor using a conductive polymer is incorporated on an aluminum conversion foil sheet having a porous state formed on at least one side, the capacitor portion independent of an arbitrary portion is provided in the component-embedded substrate. A first step of pregrooving a separation boundary portion for forming a capacitor portion and a wiring pattern in an arbitrary portion on the aluminum chemical conversion foil sheet, and forming an aluminum solid electrolytic capacitor on the grooved aluminum chemical conversion foil A second step of forming a protective coating pattern with an insulating material on a portion excluding a portion that requires exposure of the aluminum chemical conversion foil sheet, such as a portion and an extraction electrode portion, and the protective coating pattern separated on the aluminum chemical conversion foil sheet In the third step of forming a chemical polymerization, electrolytic polymerization or solid electrolytic capacitor part in the capacitor part, A protective coating material that gradually removes the surface of the aluminum conversion foil from the surface opposite to the groove-formed surface so as to have a uniform thickness in the surface direction and penetrates to the grooved bottom portion as the separation boundary portion. A fourth step of removing the surface until at least the exposed and separated portions can be electrically insulated, and the extraction electrode that enables electrical connection to an external circuit is formed on the formed solid electrolytic capacitor and wiring pattern. Manufacturing of a component-embedded board characterized in that an electrically independent capacitor portion and wiring pattern are formed in an arbitrary place at a desired size on an aluminum chemical conversion foil sheet by using a manufacturing process having a fifth process Method. The manufacturing method of the component built-in substrate according to claim 1, wherein the aluminum formed foil is formed with a double-sided porous portion. The manufacturing method of the component built-in substrate according to claim 1, wherein the aluminum conversion foil uses a heat resistant base material attached to the opposite surface of the surface on which the solid electrolytic capacitor is formed before the groove processing. The manufacturing method of the component built-in substrate according to claim 1, wherein an anode electrical extraction electrode is formed on a porous portion of the aluminum conversion foil of the solid electrolytic capacitor formed on the aluminum conversion foil sheet. The manufacturing method of the component built-in board | substrate of Claim 4 which provided the through-hole previously in the part which forms an anode electrical extraction electrode in the porous part of the aluminum chemical conversion foil of the solid electrolytic capacitor formed in the said aluminum chemical conversion foil sheet. Electrical insulation comprising a sheet formed with a solid electrolytic capacitor and a wiring pattern of a desired shape on the aluminum chemical conversion foil according to any one of claims 1 to 5 and vias and wiring patterns constituting a printed circuit board A method of manufacturing a component-embedded substrate including a solid electrolytic capacitor formed of an aluminum conversion foil by laminating and integrating at least one substrate with each other to obtain electrical connection. The component built-in substrate according to claim 1 or 6, wherein in the first step of claim 1, a dry processing method such as laser groove processing or die slit processing is used when the aluminum chemical conversion foil groove is processed. Manufacturing method. The method according to claim 1 or 6, wherein a straight buff type buffing machine is used as a method of gradually removing the surface of the aluminum chemical conversion foil from the surface opposite to the solid electrolytic capacitor forming surface in the fourth step of claim 1. A manufacturing method of the component-embedded substrate as described.

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