JP2005033813A - Shielded strip line type element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the shielded strip line type element which is low in impedance in a high-frequency region of, particularly, ≥100 MHz and is improved to operate at higher speed and at higher frequency so that the element is mainly suitable for a bypass element or decoupling element of a noise filter. <P>SOLUTION: A dielectric oxide coating film 20 is formed on the surface of a metal sheet 10 made of aluminum, and a conductive high polymer layer 31 is provided on the metal sheet 10 and the dielectric oxide coating film 20 so as to cover the sheet 10 and film 20. The conductive high polymer layer 31 is formed of a polyaniline doped with a paratoluensulfonic acid. A conductive carbon paste layer 32 and a silver paste layer 33 are provided on the outside of the conductive high polymer layer 31, and a metal sheet 40 composed of copper foil is laminated upon the silver paste layer 33. In addition, anode lead terminals 11 and 12 are connected to both ends of the metal sheet 10, and both end sections of the metal sheet 40 are constituted as cathode lead terminals 41 and 42. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shield stripline type element mounted on an electronic substrate, and more particularly, to a shield stripline type element which is mainly suitable for a noise filter bypass element or a power supply decoupling element and is intended to increase speed and frequency. .

  With the advancement of science and technology, there is a demand for miniaturization and high performance of electronic devices. For example, in switching power supplies and digital signal processing circuit components, this is achieved by increasing the clock frequency. With this increase, the high frequency current flowing in the circuit, particularly in the power supply circuit, increases, and electromagnetic radiation increases. The degradation of signal quality becomes significant. For this reason, performance requirements for the noise filter bypass element and the power supply decoupling element are becoming stricter.

  Conventionally, power decoupling elements for high-speed digital circuits have a ceramic capacitor formed by laminating multiple layers of ceramic materials deposited with a metal thin film, and a porous molded body of a valve action metal such as tantalum or aluminum as an anode. Solid electrolytic capacitors having a structure in which an oxide film of the porous molded body is used as a dielectric and a conductive polymer is used as a solid electrolyte have been developed.

  As an example of a solid electrolytic capacitor, Patent Document 1 describes a solid electrolytic capacitor in which polypyrrole or an alkyl substitution product thereof is provided as a solid electrolyte on a dielectric oxide film. Patent Document 2 describes a solid electrolytic capacitor in which polyaniline is formed as a solid electrolyte on a dielectric oxide film and a method for manufacturing the same. In these capacitors, a conductive polymer having a conductivity 100 times higher than that of the previous capacitor is used for the solid electrolyte. For this reason, these capacitors have a small equivalent series resistance, and even a capacitor having the same capacity exhibits an effect up to a high frequency region having a frequency 100 times higher than that of the previous capacitor.

  On the other hand, the configuration of a filter is also being studied in order to cope with higher frequencies. Patent Document 3 discloses a surface mount type noise filter composed of a meandering conductor and a grounding conductor sandwiched between ceramic dielectric sheets. FIG. 5 is a sectional view showing the structure of this conventional surface mount filter. As shown in FIG. 5, in a conventional surface mount filter, a rectangular first dielectric sheet 110, a second dielectric sheet 120, and a third dielectric sheet 130 are laminated to form a laminated body 153. Yes. Further, the first signal electrode 151 and the second signal electrode 152 are attached to a pair of end faces facing each other among the end faces parallel to the stacking direction in the stacked body 153.

  The first dielectric sheet 110 includes a first inner conductor 111, a second inner conductor 112, and a meandering conductor 115. The first inner conductor 111 is connected to the first signal electrode 151, and the second inner conductor 112 is a second signal electrode. The meandering conductor 115 is connected between the first inner conductor 111 and the second inner conductor 112. The second dielectric sheet 120 includes a ground conductor 125, and the ground conductor 125 is connected to a pair of ground electrodes (not shown). The ground electrode is attached to a pair of end faces to which the first signal electrode 151 and the second signal electrode 152 are not attached among the end faces of the laminated body 153 parallel to the stacking direction of the stacked body 153. The meandering conductor 115 has an inductance, and a capacitance is formed between the meandering conductor 115 and the ground conductor 125. Thereby, a noise filter combining an inductance element and a capacitance element is formed, and a noise filter having excellent high-frequency noise absorption characteristics can be obtained. In this surface mount filter, the electric signal input from the first signal electrode 151 is filtered by flowing through the first inner conductor 111, the meandering conductor 115 and the second inner conductor 112, and output from the second signal electrode 152. Is done.

Japanese Examined Patent Publication No. 4-56445 JP-A-3-35516 JP-A-6-53046

  However, the above-described conventional techniques have the following problems. Capacitors using the above-mentioned conductive polymer as a solid electrolyte are used for various applications as capacitors that can be used up to a high frequency range. Even in these capacitors, the impedance increases drastically in a high frequency range exceeding 10 MHz. . Therefore, in operation at a clock frequency of several hundred MHz, which is now common in digital circuits, it is possible to realize the characteristic that the power source impedance is almost zero regardless of the frequency assumed in the signal generation circuit. It is gone. As a result, it is impossible to meet recent demands as a filter bypass element or a power supply decoupling element.

  In addition, the surface mount filter described above has a problem in that the operating frequency range is limited by the combination of the capacitor and the series inductor, and sufficient noise removal cannot be performed over a wide frequency band. Furthermore, since this surface mount type filter has a high impedance value, there is a limit to use as a substitute for a capacitor, and there is a problem that it is difficult to realize low impedance particularly in a high frequency region of 100 MHz or more.

  The present invention has been made in view of such a problem, and particularly has a low impedance in a high frequency region of 100 MHz or more, and mainly aims at speeding up and high frequency suitable as a noise filter bypass element or decoupling element. An object of the present invention is to provide a shield stripline type element.

  The shield stripline element according to the present invention has two terminals, a high-frequency current flows between these terminals, and the cross-sectional shape perpendicular to the direction in which the high-frequency current flows is substantially constant in the current direction. A metal member made of metal, a dielectric oxide film continuously formed in the current direction on the surface between the two terminals of the metal member, and the periphery of the metal member sandwiching the dielectric oxide film And a conductive layer provided so as to surround.

  In the present invention, the metal member has a transmission line structure having a constant cross section perpendicular to the current direction, so that even if the current flowing in the metal member is a high-frequency current, the electromagnetic field in the metal member is uniform. As a result, the frequency dependence of the characteristic impedance is reduced. Moreover, a dielectric oxide film can be formed on the surface of this metal member by forming the metal member with a valve metal. The valve metal is a metal that forms a dielectric oxide film on the surface thereof. Furthermore, a shield strip line is realized by providing a conductor layer so as to surround the periphery of the metal member. The strip line is one in which conductors are arranged above and below the signal line, and the shield strip line is one in which the upper and lower conductors are connected to each other on the side of the signal line. Thereby, the magnetic flux which leaks from the side of the metal member which is a signal line can be shielded, and the characteristic impedance of an element can be reduced more. As a result, the electric signal input to the metal member can be filtered by the dielectric oxide film and the conductor layer over a wide frequency band. As a result, it is possible to realize a line-type element suitable for high speed and high frequency.

  The cross-sectional shape may be a rectangle, a circle, or a ring. The absolute value of the characteristic impedance of the element also depends on the cross-sectional shape of the metal member. When the shape of the cross section is a rectangle, the shape of the metal member is a rectangular parallelepiped shape including a flat plate shape. When the shape of the cross section is a circle, the shape of the metal member is a columnar shape. When the cross-sectional shape is a ring shape, the metal member has a cylindrical shape. The cross-sectional shape may be substantially rectangular, circular, or ring-shaped.

  The valve metal is preferably made of one or more metals selected from the group consisting of aluminum, aluminum alloys, tantalum, tantalum alloys, niobium and niobium alloys. Thereby, by oxidizing the surface of these metals, a uniform and stable dielectric oxide film having a high dielectric constant can be formed. As a result, it is possible to easily obtain a stable shield stripline element having excellent volume efficiency.

  Furthermore, the conductor layer is preferably made of a conductive polymer. As a result, even when the surface of the metal member is enlarged by etching or the like, it is possible to form a conductor layer having high conductivity that is in close contact with the dielectric layer formed on the surface of the metal member. For this reason, the shield stripline type | mold element which can be used to a high frequency area | region can be obtained easily.

  In particular, the conductive polymer is preferably made of one or more substances selected from the group consisting of polypyrrole, polythiophene, polyaniline, and derivatives thereof. Thereby, an environmental stability is excellent and a stable conductor layer can be formed up to a temperature of 100 ° C. or higher. As a result, a shield stripline element that is excellent in stability and durability and can be used up to a high frequency region can be easily obtained.

  As described above in detail, according to the present invention, the shield strip has a low impedance, particularly in a high frequency region of 100 MHz or more, and is suitable mainly as a bypass element or a decoupling element of a noise filter. A line-type element can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the following examples. First, a first embodiment of the present invention will be described. FIG. 1 is a cross-sectional view showing a shield stripline element according to the present embodiment, and FIG. 2 is a cross-sectional view showing an A-A 'cross section shown in FIG.

  As shown in FIGS. 1 and 2, in the shield stripline element according to the present embodiment, a metal plate 10 made of a valve metal and having a substantially planar shape is provided. The metal plate 10 is made of aluminum, for example. Moreover, the shape of the metal plate 10 is rectangular, for example, the thickness is 110 μm, the length is 20 mm, and the width is 10 mm. The surface of the metal plate 10, that is, the front surface, the back surface, and the end surface is enlarged by about 200 times by electrolytic etching in the electrolytic solution.

  A dielectric oxide film 20 is formed on the surface of the metal plate 10. The dielectric oxide film 20 is formed by oxidizing the surface of the metal plate 10. A conductive polymer layer 31 is formed on the dielectric oxide film 20 so as to cover the metal plate 10 and the dielectric oxide film 20. In this embodiment, the conductive polymer layer 31 is formed of polyaniline using paratoluenesulfonic acid as a dopant. The conductive polymer layer 31 is not formed at both ends of the metal plate 10 in the longitudinal direction, and the dielectric oxide film 20 is exposed. The lengths of the exposed portions in the longitudinal direction of the metal plate 10 are each 5 mm, for example. Positive electrode lead terminals 11 and 12 are connected to the exposed portions, respectively. The positive electrode lead terminals 11 and 12 are for flowing an electric signal through the metal plate 10, and therefore, the positive electrode lead terminals 11 and 12 need to be arranged at some distance from each other.

  A conductive carbon paste layer 32 is formed on the conductive polymer layer 31, and a silver paste layer 33 is formed on the conductive carbon paste layer 32. A conductive layer 30 is formed by the conductive polymer layer 31, the conductive carbon paste layer 32, and the silver paste layer 33. That is, the dielectric oxide film 20 is formed so as to cover the metal plate 10, and the conductor layer 30 is formed so as to cover a region other than the exposed portion of the dielectric oxide film 20. On one surface of the conductor layer 30, a metal plate 40 made of a copper foil having a thickness of, for example, about 100 μm is overlaid. The surface of the metal plate 40 is disposed so as to be parallel to the surface of the metal plate 10. The length of the metal plate 40 in the longitudinal direction is longer than the length of the conductor layer 30 in the longitudinal direction. Therefore, both end portions of the metal plate 40 are not overlapped with the conductor layer 30. The both end portions are negative electrode lead terminals 41 and 42, respectively.

  The metal plate 10 is not limited to aluminum as in this embodiment, and various types of metal plates can be used as long as they are valve metals. Examples of such valve action metals include aluminum, aluminum alloys, tantalum, tantalum alloys, niobium, niobium alloys, titanium, titanium alloys, zirconium, zirconium alloys, silicon, magnesium, and magnesium alloys. In addition, the metal plate 10 may be a rolled foil or a fine powder sintered body. Furthermore, the shape of the metal plate 10 may be curved or may be a partially bent shape.

  In the present embodiment, the example in which the conductor layer 30 is formed of the conductive polymer layer 31 made of polyaniline, the conductive carbon paste 32, and the silver paste 33 is shown. However, as long as the conductor layer is conductive. It is not particularly limited, and may be formed of various metals, semiconductors such as manganese dioxide and indium oxide, organic conductors such as a charge transfer complex of tetracyanoquinodimethane and tetrathiafulvalene, and the like. In particular, conductive polymers such as polypyrrole, polythiophene, polyethylenedioxythiophene, polyaniline, polyphenylene, polyfuran, polythiazyl, polyphenylene vinylene, polyacetylene and polyazulene are preferable, and among them, polypyrrole, polythiophene, polyaniline and derivatives thereof are preferable. Is preferred. In the present invention, the derivatives of polypyrrole, polythiophene, and polyaniline refer to, for example, those obtained by adding various substituents to these compounds and those copolymerized with other polymers. In the present invention, the conductive polymer is usually used in combination with a dopant composed of a compound having an electron donating property or an electron withdrawing property. In the present invention, the type of dopant is not particularly limited, and for example, a dopant made of a conductive polymer or a known dopant can be used. Examples of such dopants include those that act as Lewis acids such as halogen compounds such as iodine, chlorine and perchlorate anions, aromatic sulfonic acid compounds, and those that act as Lewis bases such as lithium and tetraethylammonium cations. Is mentioned.

  Furthermore, in this embodiment, an example in which the metal plate 40 made of a copper foil having a thickness of, for example, about 100 μm is superimposed on one surface of the conductor layer 30 is shown. However, the material of the metal plate 40 is limited to copper. Any metal having low electrical resistance such as silver, gold, and aluminum may be used. Two metal plates 40 may be provided so as to face both surfaces of the metal plate 10.

  In the present embodiment, the conductive polymer layer 31 and the metal plate 40 are connected to each other via the conductive carbon paste layer 32 and the silver paste layer 33. The paste layer 32 and the silver paste layer 33 may be omitted, and the conductive polymer layer 31 may be directly connected to the metal plate 40.

  The shield stripline type element of this embodiment can be used by mounting it on an electronic circuit board as it is, or by drawing out the lead electrode and sealing it with a resin or metal case.

  Next, the manufacturing method of the shield stripline type | mold element which concerns on a present Example is demonstrated. First, an aluminum foil having a thickness of 110 μm, a length of 20 mm, and a width of 10 mm, for example, is prepared as the metal plate 10. Next, the metal plate 10 is subjected to electrolytic etching in an electrolytic solution, whereby the surface area of the metal plate 10 is increased by about 200 times. The metal plate 10 is immersed in an aqueous solution of ammonium borate having a concentration of, for example, 5% by mass, an anodizing treatment is performed by applying a voltage of, for example, 10 V, and then washing and drying are performed. A dielectric oxide film 20 made of a film is formed. Both ends in the length direction of the metal plate 10 on which the dielectric oxide film 20 is formed, that is, a region within 5 mm from the edge is dipped in a fluororesin solution made of hexafluoropropylene, dried, and dried. A mask (not shown) made of hexafluoropropylene is formed on the part. When the capacitance is measured by immersing the metal plate 10 in a sulfuric acid aqueous solution having a concentration of 0.1 N, the capacitance is about 380 μF.

  Next, in a glass container, an aqueous solution containing, for example, 10% by mass of paratoluenesulfonic acid and, for example, 5% by mass of aniline is prepared, and the above-described dielectric oxide film 20 and mask are formed in this aqueous solution. 10 is immersed and then removed. Then, it is dried in air at room temperature for 30 minutes, for example. Next, for example, an aqueous solution containing 10% by mass ammonium peroxodisulfate and 10% by mass paratoluenesulfonic acid is prepared, the metal plate 10 is immersed in this aqueous solution, and then taken out and left in the air for another 20 minutes. Polymerize aniline. Thereafter, the metal plate 10 is washed with water and methanol and dried in an atmosphere having a temperature of 80 ° C. The above-described operations from immersion in an aqueous solution of paratoluenesulfonic acid and aniline to drying at a temperature of 80 ° C. are repeated four times. A conductive polymer layer 31 made of polyaniline using as a dopant is formed.

  Next, the conductive carbon paste layer 32 and the silver paste layer 33 are formed so as to cover the region where the conductive polymer layer 31 is formed on the surface of the metal plate 10. A conductor layer 30 is formed from the conductive polymer layer 31, the conductive carbon paste layer 32, and the silver paste layer 33. Thereafter, a metal plate 40 made of copper foil having a thickness of, for example, about 100 μm is overlaid on one surface of the conductor layer 30. Thereby, the metal plate 40 is disposed so as to face one surface of the metal plate 10 with the conductor layer 30 and the dielectric oxide film 20 interposed therebetween. The length of the metal plate 40 in the longitudinal direction is longer than the length of the conductor layer 30 in the longitudinal direction. Therefore, both end portions of the metal plate 40 in the length direction protrude without being overlapped with the conductor layer 30. Both ends of the protruding metal plate 40 are used as negative electrode lead terminals 41 and 42, respectively. Thereafter, both end portions of the metal plate 10 are immersed in tetrahydrofuran, and hexafluoropropylene, which is a resin constituting the mask, is dissolved and removed. Next, two positive electrode lead terminals 11 and 12 are connected to both ends of the metal plate 10 using an ultrasonic welder. Thereby, the shield stripline type | mold element which concerns on a present Example is produced.

  In the present embodiment, an example in which electrolytic etching is performed in an electrolytic solution as a method for increasing the surface area of the metal plate 10 has been shown. However, a metal plate with an increased surface area has a fine powder sintered body in a flat plate shape. You may produce by processing.

  Also, the method for forming the dielectric oxide film 20 is not particularly limited, and the surface of the metal plate 10 may be formed by electrolysis in an electrolyte solution or by oxidation using an appropriate oxidizing agent. Alternatively, an oxide film formed by air-oxidizing the surface of the metal plate 10 may be used as it is. However, normally, the dielectric oxide film 20 is formed by electrolytically forming the surface of the metal plate 10.

  Furthermore, in this embodiment, the positive electrode lead terminals 11 and 12 are joined to the metal plate 10 by ultrasonic welding, but this joining may be performed by a method such as pressure bonding. Further, the metal plate 10 may be protruded on both sides, and both end portions of the metal plate 10 may be used as positive electrode extraction terminals.

  Furthermore, in the present embodiment, an example in which the conductive polymer layer 31 is formed by polymerizing aniline by immersing the metal plate 10 in an aqueous solution and drying to form the conductive polymer layer 31 is shown. The method of forming the molecular layer is not limited to this, and a monomer and / or oligomer that forms a conductive polymer by applying a solution of the conductive polymer on the metal plate 10 and evaporating the solvent in the solution, and By conducting a polymerization of a conductive polymer directly on the metal plate 10 by introducing a polymerization catalyst, or by forming a polymer layer composed of an intermediate of the conductive polymer and converting it to a conductive polymer Alternatively, the conductive polymer layer 31 may be formed.

  In the shield stripline element according to the present embodiment, the high-frequency signal current input from the positive electrode extraction terminal 11 passes through the metal plate 10 and is output from the positive electrode extraction terminal 12. At this time, the signal current can be filtered by the dielectric oxide film 20 and the conductor layer 30. Since the shape of the metal plate 10 is a transmission line structure and the shape of the cross section orthogonal to the direction in which the signal current flows is substantially constant, the electromagnetic field in the metal plate 10 is uniform even if the signal current is a high-frequency current. Thus, the frequency dependence of the characteristic impedance is small.

  In addition, since the metal plate 10 is made of aluminum which is a valve action metal, a uniform and stable dielectric oxide film 20 can be easily formed on the surface of the metal plate 10. Furthermore, since the conductor layer 30 is provided so as to surround the metal plate 10, a shield strip line is realized, the magnetic flux leaking from the metal plate 10 can be shielded, and the impedance of the element can be reduced. it can. Furthermore, by providing the metal plate 40, the negative electrode lead terminals 41 and 42 can be formed, and the impedance of the element can be further reduced. Furthermore, since the conductive polymer layer 31 is provided on the conductor layer 30, a conductor layer having high adhesion to the dielectric oxide film 20 and high conductivity can be easily formed.

  With respect to the shield stripline type device according to this example, when the capacitance is measured using the metal plate 10 as an anode and the metal plate 40 as a cathode, the capacitance is about 380 μF when the frequency is 120 Hz, for example. Is sufficiently covered with polyaniline.

  In addition, two pairs of electrode lead terminals provided at both ends of the shield stripline type element, that is, the positive electrode lead terminals 11 and 12 and the negative electrode lead terminals 41 and 42 are connected to a network analyzer to connect the power transmission characteristic S21. Is −70 dB or less in the frequency region of 100 kHz to 100 MHz, and −40 dB or less at the frequency of 1 GHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

  Next, a second embodiment of the present invention will be described. The configuration of the shield stripline type element according to the present embodiment is different from the configuration of the shield stripline type element according to the first embodiment described above in that the conductive polymer layer 31 is made of polypyrrole. . The rest of the configuration of the shield stripline element of this embodiment is the same as that of the shield stripline element according to the first embodiment.

  A method for manufacturing the shield stripline element according to this embodiment will be described. First, the dielectric oxide film 20 and the mask are formed on the surface of the metal plate 10 by the same method as in the first embodiment. Next, a methanol solution containing 10% by mass of ferric dodecylbenzenesulfonate in a glass container is prepared. Then, the metal plate 10 with the dielectric oxide film 20 formed on the surface is immersed in this solution and then taken out. Next, it is dried in air at room temperature for 30 minutes. Next, this is immersed in an aqueous solution containing 50% by mass of pyrrole, then taken out and left in the air for 30 minutes to polymerize pyrrole. Then, it wash | cleans with water and methanol, and it is made to dry in the atmosphere whose temperature is 80 degreeC. The operation from the immersion in the methanol solution to the drying at a temperature of 80 ° C. is repeated four times, and a conductive polymer layer made of polypyrrole having dodecylbenzenesulfonic acid as a dopant is formed on the surface of the dielectric oxide film 20.

  Next, the conductive carbon paste layer 32 and the silver paste layer 33 are formed by the same method as in the first embodiment so as to surround the conductive polymer layer forming region on the surface of the metal plate 10 to thereby form a conductor. The layer 30 is formed, a metal plate 40 made of copper foil is attached, and both ends of the metal plate 40 are used as negative electrode lead terminals 41 and 42, respectively. Thereafter, the mask is removed by the same method as in the first embodiment, and the positive electrode lead terminals 11 and 12 are attached.

  With respect to the shield stripline element according to this example, when the capacitance is measured using the metal plate 10 made of aluminum foil as an anode and the metal plate 40 made of copper foil as a cathode, the capacitance is about 380 μF when the frequency is 120 Hz, for example. It can be seen that the surface of the dielectric oxide film 20 is sufficiently covered with polypyrrole.

  In addition, two pairs of electrode lead terminals provided at both ends of the shield stripline type element, that is, the positive electrode lead terminals 11 and 12 and the negative electrode lead terminals 41 and 42 are connected to a network analyzer to connect the power transmission characteristic S21. Is −70 dB or less in the frequency region of 100 kHz to 100 MHz, and −40 dB or less at the frequency of 1 GHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

  Next, a third embodiment of the present invention will be described. The configuration of the shield stripline type element according to the present embodiment is that the conductive polymer layer 31 is made of polyhexylthiophene as compared with the configuration of the shield stripline type element according to the first embodiment. Is different. The rest of the configuration of the shield stripline element of this embodiment is the same as that of the shield stripline element according to the first embodiment.

  A method for manufacturing the shield stripline element according to this embodiment will be described. First, the dielectric oxide film 20 and the mask are formed on the surface of the metal plate 10 by the same method as in the first embodiment. Next, a xylene solution of polyhexylthiophene having a concentration of 5% by mass is prepared in a glass container, and this solution is used as a mask in the metal plate 10 on which the dielectric oxide film 20 and the mask are formed on the surface. It is dripped at the area | region which is not formed, and is dried in the atmosphere whose temperature is 80 degreeC. Next, the entire device is immersed in an aqueous hydrochloric acid solution, and a conductive polymer layer 31 made of polyhexylthiophene using chlorine ions as a dopant is formed on the surface of the dielectric oxide film 20.

  Next, the conductive carbon paste layer 32 and the silver paste layer 33 are formed so as to surround the conductive polymer layer forming region on the surface of the metal plate 10 by the same method as in the first embodiment described above, and the conductor. The layer 30 is formed, a metal plate 40 made of copper foil is attached, and both ends of the metal plate 40 are used as negative electrode lead terminals 41 and 42, respectively. Thereafter, the mask is removed and the positive electrode lead terminals 11 and 12 are attached.

  With respect to the shield stripline element according to this example, when the capacitance is measured using the metal plate 10 made of aluminum foil as an anode and the metal plate 40 made of copper foil as a cathode, the capacitance is about 380 μF when the frequency is 120 Hz, for example. It can be seen that the surface of the dielectric oxide film 20 is sufficiently covered with polyhexylthiophene.

  In addition, two pairs of electrode lead terminals provided at both ends of the shield stripline type element, that is, the positive electrode lead terminals 11 and 12 and the negative electrode lead terminals 41 and 42 are connected to a network analyzer to connect the power transmission characteristic S21. Is, for example, −60 dB or less in the frequency region of 100 kHz to 100 MHz, and −40 dB or less at the frequency of 1 GHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

  Next, a fourth embodiment of the present invention will be described. The configuration of the shield stripline type element according to the present embodiment is that the conductive polymer layer 31 is made of polyethylene dioxythiophene as compared with the configuration of the shield stripline type element according to the first embodiment. Is different. The rest of the configuration of the shield stripline element of this embodiment is the same as that of the shield stripline element according to the first embodiment.

  A method for manufacturing the shield stripline element according to this embodiment will be described. First, the dielectric oxide film 20 and the mask are formed on the surface of the metal plate 10 by the same method as in the first embodiment. Next, an ethanol solution containing 10% by mass of ferric dodecylbenzenesulfonate is prepared in a glass container. Then, the metal plate 10 having the dielectric oxide film 20 formed on the surface is immersed in this solution, then taken out and dried in air at room temperature for 30 minutes. Next, this sample is immersed in an aqueous solution containing 50% by mass of ethylenedioxythiophene, then taken out and left in the air for 30 minutes to polymerize ethylenedioxythiophene. Then, it wash | cleans with water and methanol, and it is made to dry in the atmosphere whose temperature is 80 degreeC. The operation from immersion in the ethanol solution to drying at a temperature of 80 ° C. is repeated four times, and the conductive polymer layer 31 made of polyethylenedioxythiophene having dodecylbenzenesulfonic acid as a dopant on the surface of the dielectric oxide film 20. Form.

  Next, the conductive carbon paste layer 32 and the silver paste layer 33 are formed so as to surround the conductive polymer layer forming region on the surface of the metal plate 10 by a method similar to that of the first embodiment described above. The body layer 30 is formed, a metal plate 40 made of copper foil is attached, and both ends of the metal plate 40 are used as negative electrode lead terminals 41 and 42, respectively. Thereafter, the mask is removed by the same method as in the first embodiment, and the positive electrode lead terminals 11 and 12 are attached.

  With respect to the shield stripline element according to this example, when the capacitance is measured using the metal plate 10 made of aluminum foil as an anode and the metal plate 40 made of copper foil as a cathode, the capacitance is about 380 μF when the frequency is 120 Hz, for example. It can be seen that the surface of the dielectric oxide film 20 is sufficiently covered with polyethylene dioxythiophene.

  In addition, two pairs of electrode lead terminals provided at both ends of the shield stripline type element, that is, the positive electrode lead terminals 11 and 12 and the negative electrode lead terminals 41 and 42 are connected to a network analyzer to connect the power transmission characteristic S21. Is -60 dB or less in a frequency range of 1 MHz to 100 MHz, and is -40 dB or less at a frequency of 1 GHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

  Next, a fifth embodiment of the present invention will be described. The configuration of the shield stripline type element according to this embodiment is the same as the configuration of the shield stripline type element according to the second embodiment. That is, the conductive polymer layer 31 is made of polypyrrole.

  A method for manufacturing the shield stripline element according to this embodiment will be described. First, the dielectric oxide film 20 and the mask are formed on the surface of the metal plate 10 by the same method as in the first embodiment. Next, in a glass container, a methanol solution containing 30% by mass of ferric dodecylbenzenesulfonate is prepared and cooled to a temperature of −50 ° C. Next, pyrrole is dropped into the solution so that the concentration becomes 6% by mass, and the pyrrole is mixed by stirring the solution while keeping the temperature of the solution at −50 ° C. This solution is dropped on a region where the mask is not formed in the metal plate 10 on which the dielectric oxide film 20 and the mask are formed on the surface, and left at room temperature for 60 minutes. Thereafter, the metal plate 10 is washed with water and methanol and dried in an atmosphere having a temperature of 80 ° C. Thereby, the conductive polymer layer 31 made of polypyrrole using dodecylbenzenesulfonic acid as a dopant is formed on the surface of the dielectric oxide film 20.

  Next, the conductive carbon paste layer 32 and the silver paste layer 33 are formed so as to surround the conductive polymer layer forming region on the surface of the metal plate 10 by the same method as in the first embodiment described above, and the conductor. The layer 30 is formed, a metal plate 40 made of copper foil is attached, and both ends of the metal plate 40 are used as negative electrode lead terminals 41 and 42, respectively. Thereafter, the mask is removed and the positive electrode lead terminals 11 and 12 are attached.

  With respect to the shield stripline type element according to this example, when the capacitance is measured using the metal plate 10 made of aluminum foil as an anode and the metal plate 40 made of copper foil as a cathode, the capacitance is about 375 μF when the frequency is 120 Hz, for example. It can be seen that the surface of the dielectric oxide film 20 is sufficiently covered with polypyrrole.

  In addition, two pairs of electrode lead terminals provided at both ends of the shield stripline type element, that is, the positive electrode lead terminals 11 and 12 and the negative electrode lead terminals 41 and 42 are connected to a network analyzer to connect the power transmission characteristic S21. Is -60 dB or less in the frequency range of 1 MHz to 100 MHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

  Next, a sixth embodiment of the present invention will be described. FIG. 3 is a perspective view showing a shield stripline element according to this embodiment. As shown in FIG. 3, in the shield stripline element according to the present embodiment, a molded body 13 made of a sintered body of tantalum powder having an average particle diameter of, for example, 0.5 μm is provided. The shape of the molded body 13 is a rectangular parallelepiped. For example, the width is 3 mm, the length is 3 mm, and the thickness is 1.8 mm. Tantalum wires 14 and 15 are connected to both ends of the molded body 13, respectively. The diameter of the tantalum wires 14 and 15 is, for example, 0.3 mm. A metal member 16 is formed by the molded body 13 and the tantalum wires 14 and 15.

  Further, a dielectric oxide film (not shown) is formed on the surface of the molded body 13, and the surface of the dielectric oxide film is surrounded from the inside so as to surround the molded body 13 and the dielectric oxide film. A conductive polymer layer, a conductive carbon paste layer, and a silver paste layer are sequentially formed. The conductive layer 35 is formed by the conductive polymer layer, the conductive carbon paste layer, and the silver paste layer. Positive electrode lead terminals 11 and 12 are connected to the tantalum wires 14 and 15, respectively.

  On one surface of the conductor layer 35, a metal plate 40 made of a copper foil having a thickness of, for example, about 100 μm is overlaid. The length of the metal plate 40 in the longitudinal direction is longer than the length of the conductor layer 35 in the longitudinal direction. Therefore, both end portions of the metal plate 40 are not overlapped with the conductor layer 35. Then, both end portions of the metal plate 40 serve as negative electrode lead terminals 41 and 42, respectively.

  Next, the manufacturing method of the shield stripline type | mold element which concerns on a present Example is demonstrated. First, a tantalum powder having an average particle size of 0.5 μm, for example, is filled into a container having an inner width of, for example, 3 mm, an inner length of, for example, 3 mm, and an inner thickness of, for example, 1.8 mm. Tantalum wires 14 and 15 having a diameter of, for example, 0.3 mm are attached to both ends of the lump to be pressure-molded. The molded body is heated to a temperature of 2000 ° C. in a vacuum to produce a molded body 13 which is a tantalum powder sintered body and a metal member 16 composed of tantalum wires 14 and 15.

  Next, the metal member 16 is anodized by applying a chemical voltage of, for example, 10 V in a phosphoric acid aqueous solution having a concentration of, for example, 0.05% by mass, and then washed and dried. A dielectric oxide film (not shown) made of a metal oxide film is formed on the surface. The portions of the tantalum wires 14 and 15 in the metal member 16 are immersed in a fluororesin solution made of hexafluoropropylene and dried to form a mask (not shown) that covers the tantalum wires 14 and 15. When this metal member 16 is immersed in a sulfuric acid aqueous solution having a concentration of 0.1 N and the capacitance is measured, the capacitance is about 300 μF.

  Next, in a glass container, a methanol solution containing 10% by mass of ferric dodecylbenzenesulfonate is prepared, and the metal member 16 having the dielectric oxide film 20 formed on the surface is immersed in this solution. Then take out. This metal member 16 is left to dry in room temperature air for 30 minutes. Next, this metal member 16 is immersed in an aqueous solution containing 50% by mass of pyrrole, then taken out and left in the air for 30 minutes to polymerize pyrrole. Thereafter, this is washed with water and methanol, and dried in an atmosphere having a temperature of 80 ° C. The operation from immersion in methanol solution to drying at a temperature of 80 ° C. is repeated 4 times, and a conductive polymer layer (not shown) made of polypyrrole having dodecylbenzenesulfonic acid as a dopant on the surface of the dielectric oxide film. Form.

  Next, a conductive carbon paste layer and a silver paste layer are formed so as to surround a region where the conductive polymer layer is formed on the surface of the metal member 16. The conductor layer 35 is formed by the conductive polymer layer, the conductive carbon paste layer, and the silver paste layer. A metal plate 40 made of copper foil is attached to one surface of the conductor layer 35. The length of the metal plate 40 in the longitudinal direction is longer than the length of the conductor layer 35 in the same direction, and both end portions of the metal plate 40 are not in contact with the conductor layer 35. Both ends of the metal plate 40 are used as negative electrode lead terminals 41 and 42, respectively. Thereafter, the mask is removed, and positive electrode lead terminals 11 and 12 are attached to the tantalum wires 14 and 15, respectively. Thereby, the shield stripline type device according to the present embodiment is manufactured.

  In the shield stripline element according to this embodiment, the high-frequency signal current input from the positive electrode extraction terminal 11 passes through the metal member 16 and is output from the positive electrode extraction terminal 12. At this time, the signal current can be filtered by the dielectric oxide film and the conductor layer 35. The shape of the metal member 16 is a transmission line structure, and the shape of the cross section perpendicular to the direction in which the signal current flows is substantially constant. Therefore, even if the signal current is a high frequency current, the electromagnetic field in the metal member 16 is uniform Thus, the frequency dependence of the characteristic impedance is small.

  Further, since the metal member 16 is made of tantalum, which is a valve action metal, a uniform and stable dielectric oxide film can be easily formed on the surface of the metal member 16. Furthermore, since the conductor layer 35 is provided so as to surround the metal member 16, a shield strip line can be realized, the magnetic flux leaking from the metal member 16 can be shielded, and the impedance of the element can be reduced. Furthermore, by providing the metal plate 40, the negative electrode lead terminals 41 and 42 can be formed, and the impedance of the element can be further reduced. Furthermore, since the conductive polymer layer made of polypyrrole is provided on the conductive layer 35, a conductive layer having high adhesion to the dielectric oxide film and high conductivity can be easily formed.

  Furthermore, in the present embodiment, since the molded body 13 is produced by the powder sintering method, the molded body 13 can be easily processed into an arbitrary shape. Further, the surface area of the molded body 13 can be increased without etching the metal plate 10 (see FIG. 1) as in the first to fifth embodiments described above.

  With respect to the shield stripline element according to the present embodiment, when the capacitance is measured using the metal member 16 made of fine tantalum metal as the anode and the metal plate 40 made of copper foil as the cathode, the capacitance is about 280 μF when the frequency is 120 Hz, for example. It can be seen that the surface of the dielectric oxide film is sufficiently covered with polypyrrole.

  In addition, two pairs of electrode lead terminals provided at both ends of the shield stripline type element, that is, the positive electrode lead terminals 11 and 12 and the negative electrode lead terminals 41 and 42 are connected to a network analyzer to connect the power transmission characteristic S21. Is -60 dB or less in the frequency region of 100 kHz to 100 MHz, and is -40 dB or less in the frequency region of 1 GHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

  Next, a seventh embodiment of the present invention will be described. FIG. 4 is a perspective view showing a shield stripline element according to this embodiment. As shown in FIG. 4, in the shield stripline element according to the present embodiment, a metal columnar member 17 made of aluminum having a diameter of 5 mm and a length of 100 mm is provided. Both end portions of the cylindrical metal member 17 are positive electrode lead terminals 11a and 12a. The positive electrode lead terminals 11a and 12a are formed with screw holes 11b and 12b, respectively.

  A dielectric oxide film 21 is formed on the surface of the cylindrical metal member 17, and a conductive polymer layer made of polyaniline having paratoluenesulfonic acid as a dopant in order from the inside on the outer side of the dielectric oxide film 21, A conductive carbon paste layer and a silver paste layer are provided. A conductor layer 36 is formed by the conductive polymer layer, the conductive carbon paste layer, and the silver paste layer. A metal plate 40 made of a copper foil having a thickness of, for example, about 100 μm is connected to the conductor layer 36. The longitudinal direction of the metal plate 40 coincides with the axial direction of the metal columnar material 17. The length in the longitudinal direction of the metal plate 40 is longer than the length of the conductor layer 36 in the same direction, so that both end portions of the metal plate 40 are not in contact with the conductor layer 36. Both end portions of the metal plate 40 serve as negative electrode lead terminals 41a and 42a, respectively. The negative electrode lead terminals 41a and 42a are formed with screw holes 41b and 42b, respectively.

  Hereinafter, a method for manufacturing a shield stripline element according to the present embodiment will be described. First, as the metal columnar material 17, a column made of aluminum having a diameter of 5 mm and a length of 100 mm is prepared. Both ends of the cylindrical metal member 17 are used as positive electrode lead terminals 11a and 12a, respectively. Further, holes 11b and 12b for screwing are formed in the positive electrode lead terminals 11a and 12a, respectively. Next, the metal columnar material 17 is immersed in an aqueous solution of ammonium borate having a concentration of 5% by mass, and a voltage of 10 V is applied to perform anodization. Thereafter, cleaning and drying are performed to form a dielectric oxide film 21 made of a metal oxide film on the surface of the metal columnar material 17. Next, fluorine resin made of hexafluoropropylene is formed on both ends of the metal columnar material 17 at 10 mm each. A mask (not shown) is formed on both ends of the metal columnar member 17 by dipping in the solution.

  Next, an aqueous solution containing 10% by mass of paratoluenesulfonic acid and 5% by mass of aniline is prepared in a glass container. Next, the cylindrical metal material 17 on which the above-described dielectric oxide film 21 is formed is immersed in this aqueous solution, then taken out and left in room temperature air for 30 minutes to dry. Next, this is immersed in an aqueous solution containing 10% by mass ammonium peroxodisulfate and 10% by mass paratoluenesulfonic acid, and then taken out and left in the air for 20 minutes to polymerize aniline. Then, it wash | cleans with water and methanol, and it is made to dry in the atmosphere whose temperature is 80 degreeC. This operation is repeated four times to form a conductive polymer layer made of polyaniline having paratoluenesulfonic acid as a dopant on the surface of the dielectric oxide film 21.

  Next, a conductive carbon paste layer and a silver paste layer are formed so as to surround a region where the conductive polymer layer is formed on the surface of the metal columnar member 17. The conductive layer 36 is formed by the conductive polymer layer, the conductive carbon paste layer, and the silver paste layer. Next, a metal plate 40 made of a copper foil having a thickness of, for example, about 100 μm is connected to the conductor layer 36. Both ends of the metal plate 40 are used as negative electrode lead terminals 41a and 42a, respectively. Next, holes 41b and 42b for screwing are formed in the negative electrode lead terminals 41a and 42a, respectively. Thereafter, both ends of the cylindrical metal member 17 are immersed in tetrahydrofuran to dissolve and remove the hexafluoropropylene that is the mask resin. Thereby, the shield stripline type device according to the present embodiment is manufactured.

  In the shield stripline type element according to the present embodiment, the high-frequency signal current input from the positive electrode extraction terminal 11a passes through the metal columnar member 17 and is output from the positive electrode extraction terminal 12a. At this time, the signal current can be filtered by the dielectric oxide film 21 and the conductor layer 36. The shape of the metal columnar material 17 is a transmission line structure, and the shape of the cross section orthogonal to the direction in which the signal current flows is substantially constant. Therefore, even if the signal current is a high-frequency current, the electromagnetic field in the metal columnar material 17 is It becomes uniform and the frequency dependence of the characteristic impedance is small.

  Moreover, since the metal columnar member 17 is formed of aluminum which is a valve action metal, a uniform and stable dielectric oxide film can be easily formed on the surface of the metal columnar member 17. Furthermore, since the conductor layer 36 is provided so as to surround the metal columnar material 17, a shield strip line can be realized, the magnetic flux leaking from the metal columnar material 17 can be shielded, and the impedance of the element can be reduced. it can. Furthermore, by providing the metal plate 40, the negative electrode lead terminals 41a and 42a can be formed, and the impedance of the element can be further reduced. Furthermore, since the conductive polymer layer made of polyaniline is provided on the conductive layer 36, a conductive layer having high adhesion to the dielectric oxide film and high conductivity can be easily formed.

  Furthermore, in this embodiment, the positive electrode lead terminals 11a and 12a and the negative electrode lead terminals 41a and 42a are formed with screw holes 11b, 12b, 41b, 42b, respectively. 12a and negative electrode lead terminals 41a and 42a can be externally connected by screws. For this reason, a large current can flow stably through the shield stripline type element.

  With respect to the shield stripline type element according to this example, when the capacitance is measured using the metal columnar material 17 as an anode and the metal plate 40 made of copper foil as a cathode, the capacitance is about 10 μF, and the surface of the dielectric oxide film is sufficient. It can be seen that it is coated with polyaniline.

  Further, when measuring the power transmission characteristic S21 by connecting two pairs of electrode lead terminals provided at both ends of this shield stripline type element, that is, screw holes 11a, 12a, 41a and 42a to a network analyzer. , It is −40 dB or less in the frequency range of 100 kHz to 1 GHz. Thus, it can be seen that the shield stripline element according to the present example has extremely excellent characteristics as a power supply decoupling element of a high-speed digital circuit, as compared with a conventional capacitor.

It is sectional drawing which shows the shield stripline type | mold element which concerns on a present Example. It is sectional drawing which shows the A-A 'cross section shown in FIG. It is a perspective view which shows the shield stripline type | mold element which concerns on the 6th Example of this invention. It is a perspective view which shows the shield stripline type | mold element which concerns on the 7th Example of this invention. It is sectional drawing which shows the structure of the conventional surface mount filter.

Explanation of symbols

10; metal plates 11, 11a, 12, 12a; positive electrode lead terminals 11b, 12b; holes 13; molded bodies 14, 15; tantalum wires 16; metal members 17; metal columnar materials 20, 21; Conductive layer 31; conductive polymer layer 32; conductive carbon paste layer 33; silver paste layers 35 and 36; conductive layer 40; metal plates 41 and 42; negative electrode lead terminal 110; First inner conductor 112; second inner conductor 115; meandering conductor 120; second dielectric sheet 125; ground conductor 130; third dielectric sheet 151; first signal electrode 152; second signal electrode 153;

Claims (7)

  A metal member made of a valve metal that has two terminals, a high-frequency current flows between these terminals, and a cross-sectional shape perpendicular to the direction in which the high-frequency current flows is substantially constant in the current direction; A dielectric oxide film continuously formed in the current direction on the surface between the two terminals, and a conductor layer provided so as to surround the metal member with the dielectric oxide film interposed therebetween; A shield stripline type element characterized by comprising:   The shield stripline element according to claim 1, wherein the cross-sectional shape is rectangular.   The shield stripline element according to claim 1, wherein the cross-sectional shape is circular.   The shield stripline element according to claim 1, wherein the cross-sectional shape is a ring shape.   The valve-acting metal is made of one or more metals selected from the group consisting of aluminum, aluminum alloy, tantalum, tantalum alloy, niobium, and niobium alloy. The shield stripline type element according to the item.   The shield stripline element according to any one of claims 1 to 5, wherein the conductor layer is made of a conductive polymer. The shield stripline element according to claim 6, wherein the conductive polymer is made of one or more substances selected from the group consisting of polypyrrole, polythiophene, polyaniline, and derivatives thereof.

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