JP2005129550A - Composite lc component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite LC component that is constituted by integrating a capacitor capable of obtaining a high capacitance and an inductor capable of obtaining a high inductance with each other so that the height and mounting area of the component may be reduced. <P>SOLUTION: The composite LC component 1 is constituted as an integrated and height-reduced composite component by disposing a thin film soft magnetic material 6 on at least one thin solid electrolytic capacitor 8, and a thin film circuit board 7; obtaining the inductor by forming a helical coil 5 on the outer peripheries of the capacitor 8, circuit board 7, and magnetic material 6; and, at the same time, electrically connecting the inductor to the capacitor 8 through the circuit board 7. By this constitution, the thin composite LC component which has a high capacitance and high inductance and can be mounted easily is obtained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a thin LC composite component suitable for use in a device that mainly requires downsizing, such as a power supply device using a switching regulator.

  A power supply device using various switching regulators, for example, a DC-DC converter that steps down the voltage stored in various secondary batteries to a voltage of 0.5 to 1.2 V in order to drive a low-voltage IC, For an application driven by a solar cell, various capacitors and inductors are used for a power source that boosts a voltage of 0.8 to 1.4 V generated by the solar cell to 5V.

  Considering the shape classified as a chip component, the shape is from an element having a small dimension of 1 mm or less such as 0603 system or 1005 system to an element having a large overall dimension exceeding 5 mm square such as 5750 system, Used in various ways.

  A high-capacitance capacitor having a capacitance of 10 μF or more and a high-inductance inductor having an inductance of 10 μH or more generally have a large shape, and when they are mounted on a substrate, the element height may increase in a large area. Many of them hindered the thinning of equipment.

  At present, devices including power supply circuits are not only made thinner, but also cost-effective, multifunctional, highly integrated, and energy-saving. As a result, driving frequency is increased, element loss is reduced. High efficiency and further compounding between elements have been studied, and restrictions on element dimensions for mounting are becoming stricter.

  Therefore, many technologies for integrating passive components such as inductors and capacitors have been proposed in order to make them easy to use.

  For example, in Patent Document 1, a chip capacitor element and an air-core coil element are arranged so as to be on one plane, and the entire passive component is embedded in a composite made of magnetic powder and a thermosetting resin. In this way, an integrated LC composite component is disclosed. However, although the height can be reduced, since the completed air-core coil and capacitor are arranged, it is difficult to reduce the size because the gap between the two is large.

  In addition, in order to construct a small LC composite component, Patent Document 2 describes a winding coil wound around a core base having a structure in which a capacitor is held inside a gate-shaped block ferrite core. LC composite parts comprising However, this method is also considered to be difficult to reduce the height because the portal block-shaped core base is a ferrite core.

  Furthermore, in order to reduce the size, Patent Document 3 proposes a structure in which a spiral planar inductor having ferrite magnetic films formed on the upper and lower surfaces of a multilayer capacitor is arranged. Although this spiral planar inductance is suitable as an element for passing a large current, it is difficult to obtain a large inductance structurally.

  We have previously disclosed an LC composite component having an integrated structure in which a high-Q inductor can be formed using a high-Q magnetic body around at least two multilayer ceramic capacitors. However, when a multilayer ceramic capacitor is used, the total thickness of the LC composite component cannot be reduced due to the problem of bending strength, which is a drawback of porcelain.

JP 2001-176728 A Japanese Patent Laid-Open No. 08-236356 JP 2002-222712 A JP 2002-198223 A

  As described above, for use in power supply circuits and sensor circuits using switching regulators, there is a demand for LC components that have a low mounting height and can provide large values of capacitance and inductance. Such an LC composite component is considered to be able to realize a low-profile LC component if a low-profile, high-capacity, low-ESR capacitor and a high-inductance, high-Q inductor can be integrated into a thin shape. However, it has been difficult to realize in the past.

  Therefore, the present invention presents a specific means for integrating a capacitor capable of obtaining a high capacity and an inductor capable of obtaining a high inductance so that a low profile and a small mounting area can be obtained, and can satisfy the above-mentioned demand. We are going to provide LC composite parts.

  In order to solve the above-described problems, an LC composite component according to the present invention includes a soft magnetic thin film disposed on at least one thin solid electrolytic capacitor element to form at least one wound helical inductor, and a thin film circuit board. It is configured as a composite part that is integrated and reduced in height by being connected by the cable. With this configuration, a passive component group composed of a high-capacity capacitor and a high-inductance inductor combined with a low profile and a low volume can be easily connected to a desired device.

  In the above configuration, a solid electrolytic capacitor having a plate-like or foil-like surface-enhanced aluminum metal having an anode body and a functional polymer as a solid electrolyte and having a characteristic of 10 μF or more is used. Is desirable. This capacitor is suitable for lowering the height because a high capacity of 10 μF or more can be obtained even if a single anode body is used without being laminated. The aluminum solid electrolytic capacitor is optimal as a component that achieves the purpose of thinning.

  That is, the present invention includes a thin solid electrolytic capacitor and a circuit board for connecting the solid electrolytic capacitor and the inductor, and further, a helical inductor is formed by winding the outer periphery of the solid electrolytic capacitor as the inductor. LC composite parts.

  Further, according to the present invention, the solid electrolytic capacitor has a plate-like or foil-like surface-enhanced metal having an anode body and a functional polymer as a solid electrolyte. The LC composite component is an electrolytic capacitor.

  Further, according to the present invention, the wound helical inductor is formed by laminating one or more insulating thin film magnetic bodies each having a soft magnetic thin film formed on at least one of a pair of opposed outer surfaces of the solid electrolytic capacitor. Further, the LC composite component is an inductor having a characteristic of 10 μH or more, which is formed by winding with an insulation coated conductor.

  In the present invention, the circuit board includes a circuit pattern to which the terminal of the solid electrolytic capacitor and the inductor are connected, and an external terminal to be connected to a circuit of a device on which the component is mounted, and the wall surface of the solid electrolytic capacitor It is LC composite component characterized by having been arrange | positioned.

  With the above configuration, it is possible to obtain a low-capacity, high-inductance LC composite element that is thin, and can be used as a step-up or step-down DC-DC converter using a switching regulator or a power source for sensors. A low-profile LC composite element suitable for use can be provided.

  In the present invention, one or more solid electrolytic capacitors are used as a high-capacitance capacitor, and a magnetic layer is further provided on a circuit board to which the capacitor is connected, and one or more wound-type helical inductors are formed on the outer periphery thereof. A capacitor and an inductor are integrated.

  First, an aluminum solid electrolytic capacitor considered to be most suitable as the solid electrolytic capacitor used in the present invention will be described. The thickness of the aluminum solid electrolytic capacitor can be reduced by using an aluminum foil having a thickness of 300 μm or less as an anode body and applying an area-enhancing process by making the aluminum surface uneven by etching. Next, a thin oxide film as a dielectric is formed along the surface of the aluminum subjected to the surface expansion treatment. A conductive polymer such as polypyrrole is formed as a solid electrolyte on the surface of the oxide film as a counter electrode of the aluminum anode body, and a graphite layer and a silver paste layer are further formed. An aluminum anode body is connected to a circuit board using an anode and a conductive paste layer such as silver paste as a cathode. By using a conductive polymer, the conductivity can be improved by two to three orders of magnitude compared to the conventional product, and this can dramatically reduce the ESR to the mΩ level.

  Using such a solid electrolytic capacitor, a circuit board on which a capacitor circuit routing pattern and an inductor circuit routing pattern are formed is attached to the terminal side of the capacitor. This circuit board is used for both electrical connection between elements and insulation of the capacitor. A thin film circuit board in which a circuit pattern is bonded to a polyimide thin film with copper can be used as the circuit board.

  In addition, one or more layers of insulating thin film magnetic bodies on which soft magnetic thin films are formed are laminated on the pasted solid electrolytic capacitor and thin film circuit board, and these are used as winding cores (magnetic cores), with insulation coated conductors on the outer periphery. A helical inductor can be obtained by forming a helical coil by applying a predetermined number of dense windings using. Both ends of the helical coil are connected to the terminals of the thin film circuit board using solder or conductive paste.

  The insulation-coated conductor is preferably an insulation-coated copper wire, but is not particularly limited. In order to reduce the thickness, a rectangular wire that can form a dense winding without generating a gap between the windings is desirable, but this is not particularly limited.

  As the composition of the soft magnetic thin film, a CoFeSiB system or a CoZrNb system can be used. Sputtering this composition on an insulating resin such as polyimide, laminating several layers of thin-film insulators with the same magnetization axis, and using an insulating thin-film magnetic body joined using thermocompression bonding or an adhesive An inductor having a high Q value and a high inductance value can be obtained. In addition, if a soft magnetic thin film is formed using ferrite powder with an average particle size of 1 μm or less and this insulating thin film magnetic material is wound around a capacitor, some characteristics can be obtained. Is also possible.

  Further, the helical coil may be covered with an insulating coating, and at this time, it may be covered with an insulating soft magnetic film. Further, the Q value can be improved by forming a closed magnetic circuit at least at one end face. Therefore, a soft magnetic thin film may be wound so that the densely wound coil is wound in the magnetic material.

  Using a solid aluminum electrolytic capacitor with excellent thinness as the core, a magnetic layer is formed, and a helical coil is formed by densely winding a conductive wire on the outer periphery of the capacitor, resulting in a thin, high capacity, high inductance LC composite parts can be obtained.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram illustrating an LC composite component according to the first embodiment. 2 and 3 are cross-sectional views taken at the broken line positions 3 and 4 shown in this schematic diagram.

  First, a method for producing a functional polymer aluminum solid electrolytic capacitor will be described. A resist is applied to a predetermined portion of a high purity aluminum metal foil (thickness of 100 μm) having an aluminum purity of 99.9% or more, the surface is roughened by etching, and the effective area is increased 100 times or more. A dielectric film was formed by anodizing.

  A functional polymer layer having high conductivity was formed on the dielectric film, a carbon conductive layer was further formed, and a silver paste conductive layer having a predetermined shape was further formed thereon. The thickness of the component functioning as the solid electrolytic capacitor 8 was 200 μm. The capacity of the completed solid electrolytic capacitor 8 was 10 μF.

  Next, the thin film circuit board 7 is formed. This substrate connects the solid electrolytic capacitor 8 and the inductor, and further attaches the external terminal 11 of the LC composite component 1 and also plays a role of insulation between the solid electrolytic capacitor 8 and the wiring pattern.

  The thin film circuit board 7 used was a board obtained by patterning a 12 μm thick polyimide base material with a 30 μm thick copper foil by rolling. Through holes were formed at locations where the upper and lower surfaces of the substrate were connected to make the patterns conductive.

  Next, the magnetic core of the inductor is formed. A soft magnetic thin film is formed while applying a DC magnetic field of 3000 to 5500 A / m to the substrate surface using a magnetron sputtering apparatus capable of obtaining a vacuum of 1 Pa or less. In this way, a CoFeSiB soft magnetic thin film having a thickness of 5 μm was formed on one side of a polyimide-based organic insulating substrate having a thickness of 12 μm and the longitudinal direction was aligned with the hard axis direction in a magnetic field. Three layers of this insulating thin-film soft magnetic material were laminated by thermocompression bonding, and one insulating thin-film magnetic material 6 cut into a strip shape having a length of 4 mm and a width of 3 mm was prepared. Further, the insulating thin film magnetic body 6 cut into the strip shape is disposed on the thin film circuit board 7 so that the terminal portions on the thin film circuit board 7 are exposed.

  A thin film circuit board 7 on which a thin film magnetic body 6 is disposed is sandwiched between a prepreg resin 9 having a thickness of 100 μm sandwiched between the terminal side of the solid electrolytic capacitor 8 having a thickness of 200 μm (side of the circuit connection 10). The thin film magnetic body 6 was attached to the remaining surface of the solid electrolytic capacitor 8 while sandwiching the prepreg resin 9 in a sandwich shape. The connection of the terminal of the solid electrolytic capacitor 8 and the thin film circuit board 7 (connection 10 with the circuit) was joined using a conductive adhesive.

  A helical coil 5 was manufactured by winding a predetermined number of times using an insulation-coated copper wire having an outer diameter of 30 μm so as to go around the completed element. After winding, the insulating coating at the end of the insulating coated copper wire was peeled off and bonded onto the thin film circuit board 7 using a conductive adhesive. The completed inductor was 10 μH.

  The thickness of the LC composite component 1 was 500 μm. This thickness is sufficiently evaluated by being comparable to the maximum thickness of a 1005 (1 mm × 0.5 mm) shape that has been evaluated as being small from the market compared to chip components. Further, although the thickness of the exterior coating is increased, the exterior coating may be performed using an epoxy resin or the like if necessary.

  The connection to the device on which the LC composite component 1 is mounted can use the pads of the thin film circuit board 7. However, if a package is required, the external terminal 11 can be used as a surface mount type QFP or the like when manufacturing the thin film circuit board. Join the pin terminals.

  This LC composite component 1 was used for a step-up converter using a switching regulator that boosts a voltage of 0.8 to 1.4 V generated by a solar cell to 5 V. The power supply of 5V is a voltage for driving the application. The 10 μF capacitor connected to the output side from the solar cell was optimal as a high-capacitance and low-ESR capacitor in order to suppress input ripple due to power switching. In addition, the 10 μH inductor was effective for minimizing fluctuations in the power supply voltage by lowering the output impedance of the solar cell. Other chip parts such as capacitors were made of commercially available 1005 shapes. The completed power supply had the same height as the bare chip of the switching regulator, and the entire power supply was within 0.7 mm, so that the thickness of the power supply could be reduced.

  FIG. 2 is a schematic diagram illustrating an LC composite component according to the second embodiment. 5 and 6 are cross-sectional views taken along the broken line positions 3 and 4 shown in this schematic diagram.

  The manufacture of the solid electrolytic capacitor 8 shown in this embodiment is performed by the same method as in the first embodiment. However, two solid electrolytic capacitors 8 having a predetermined capacity are prepared. However, a resist was applied to the portions other than the capacitance forming portions of the respective capacitors to form capacitors of 100 nF and 10 μF.

  Next, a thin film circuit board 7 on which the thin film magnetic body 6 is disposed is produced. In order to carry out the wiring of the capacitors that overlap vertically, a thin film circuit board having a size obtained by adding the size of one or two capacitor end faces to the size of two capacitor planes is prepared. At least two laminated substrates obtained by patterning with a copper foil having a thickness of 5 μm by a plating method on a polyimide base material having a thickness of 9 μm in advance were used. Through holes were formed at locations where the upper and lower surfaces of the substrate were connected to make the patterns conductive. Two thin film magnetic bodies 6 corresponding to the plane of the solid electrolytic capacitor 8 are thermocompression bonded to the thin film circuit board 7 at predetermined positions.

  As the thin film circuit board 7, a U-shaped thin film circuit board 12 was used in order to join the solid electrolytic capacitors stacked in two stages so as to cover them in a U shape. In this embodiment, a U-shaped thin film circuit board 12 having a thickness corresponding to two end faces of the solid electrolytic capacitor 8 is used, and the terminal surface faces outward with the prepreg resin 9 sandwiched between two 200 μm solid electrolytic capacitors 8. (Connection 10 with circuit). Solid electrolytic capacitors may be stacked in the same direction using a U-shaped thin film circuit board having a thickness equivalent to one capacitor end face, and bonded using a prepreg resin with the thin film circuit board sandwiched therebetween. In this case, the thin film circuit board is joined so as to cover one solid capacitor in a U-shape.

  A helical inductor 5 was formed by winding a predetermined number of turns using an insulation-coated copper wire having an outer diameter of 20 μm so as to circulate the completed element. After winding, the insulating coating at the end of the insulating coated copper wire was peeled off and bonded onto the thin film circuit board 7 using a conductive adhesive. The finished inductor is 10 μH. Further, a surface mount type external terminal 11 is provided for connection to a device on which the LC composite component 1 is mounted.

  The thickness of the LC composite component 1 was 700 μm. This thickness is evaluated as being comparable to the maximum thickness of 1208 (1.2 mm × 0.8 mm) in comparison with the chip component.

  This LC composite component 1 was used for a step-up converter using a switching regulator that boosts a voltage of 0.8 to 1.4 V generated by a solar cell to 5 V. The power supply of 5V is a voltage for driving the application. The 10 μF capacitor connected to the output side from the solar cell was optimal as a high-capacitance and low-ESR capacitor in order to suppress input ripple due to power switching. In addition, the 10 μH inductor was effective for minimizing fluctuations in the power supply voltage by lowering the output impedance of the solar cell. A 100 nF capacitor was connected to the ground line from the switching regulator. The completed power supply had the same height as the converter, and the entire power supply was within 1 mm, so that the power supply was thinned.

1 is a schematic view of an LC composite component using one solid electrolytic capacitor and one inductor according to the present invention. FIG. Sectional drawing (3 positions) of FIG. Sectional drawing (4 positions) of FIG. The figure which shows LC composite component using two solid electrolytic capacitors and one inductor of this invention. Sectional drawing (3 positions) of FIG. Sectional drawing (4 positions) of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 LC composite component 2 Polarity 3 Break line which shows cross-sectional position in length direction 4 Break line which shows cross-sectional position in width direction Helical coil 6 Thin film magnetic body 7 Thin film circuit board 8 Solid electrolytic capacitor 9 Prepreg resin 10 Connection with circuit 11 External Terminal 12 U-shaped thin film circuit board

Claims (4)

  An LC composite component comprising a thin solid electrolytic capacitor and a circuit board for connecting the solid electrolytic capacitor and an inductor, and further forming a helical inductor by winding the inductor around the outer periphery of the solid electrolytic capacitor.   The solid electrolytic capacitor is a solid electrolytic capacitor having a characteristic of 10 μF or more in which a plate-like or foil-like surface-enhanced metal having an anode function is used as an anode body and a functional polymer is used as a solid electrolyte. The LC composite component according to claim 1.   The wound helical inductor is formed by laminating one or more layers of an insulating thin film magnetic body formed with a soft magnetic thin film on at least one of a pair of opposed outer surfaces of the solid electrolytic capacitor. The LC composite component according to claim 1, wherein the LC composite component is an inductor having a characteristic of 10 μH or more formed by winding.   The circuit board includes a circuit pattern to which the terminal of the solid electrolytic capacitor and the inductor are connected, and an external terminal to be connected to a circuit of a device on which the component is mounted, and is disposed on the wall surface of the solid electrolytic capacitor. The LC composite component according to claim 1.

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