JP2007005501A - Capacitor element and non-reciprocal circuit element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decrease a capacity tolerance (variations) caused by misregistration of inter-electrodes formed on a dielectric board. <P>SOLUTION: A capacitor element comprises a first electrode and a second electrode, and the first electrode contains two or more capacity electrodes which are disposed at a distance in the thickness direction of a lamination board and are electrically connected to each other. The second electrode is disposed between adjoining two capacity electrodes in the thickness direction of the lamination board among the two or more capacity electrodes to form an electrostatic capacity between the first electrode and the second electrode. The second electrode contains at least the two capacity electrodes, which are disposed at a distance in the thickness direction of the lamination board and are electrically connected to each other. Preferably, the distance between the two capacity electrodes, included in the second electrode, is greater than the distance between the capacity electrode of the first electrode and the capacity electrode of the second electrode which form the electrostatic capacity so as to face each other. This is suitable for use as a matching capacitor of a non-reciprocal circuit element (isolator). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a capacitor element and a non-reciprocal circuit element, and more particularly to a structure of a capacitor formed in a multilayer substrate to constitute a non-reciprocal circuit element such as an isolator.

  As one of the passive circuit elements, a capacitor constitutes an electronic circuit and may be incorporated into various electronic components and circuit modules. For example, a nonreciprocal circuit element (isolator) is provided at a front end portion of a mobile communication device such as a mobile phone in order to cut off reflected power from an antenna. This isolator includes a magnetic rotor composed of a soft magnetic body and three central conductors arranged so as to intersect with each other at a predetermined angle, a magnet for applying a DC magnetic field to the magnetic rotor, A terminal resistor and a plurality of matching capacitors are accommodated in a resin case (see Patent Documents 1 and 2 below). The matching capacitor has one end connected between the central conductor and each terminal (an input terminal, an output terminal, or a termination terminal connecting the termination resistor), and the other end connected to the ground.

  Such an isolator is inserted between an antenna and a transmission power amplifier in a mobile phone, and allows transmission signals transmitted from the power amplifier to the antenna to pass therethrough, while blocking unnecessary power reflected from the antenna side. Unnecessary power from the antenna side is consumed as thermal energy by the termination resistor, but it is preferable to efficiently release this heat to the outside in terms of improving the characteristics of the isolator. For this reason, in the invention of Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-241944), the heat radiation from the termination resistor is enhanced by arranging the termination resistor and the ground terminal electrode in a specific arrangement.

  On the other hand, the matching capacitor is advantageously composed of a single plate capacitor in which flat electrodes are formed on both outer surfaces of the dielectric substrate from the viewpoint of obtaining a high Q value. However, since a single-plate capacitor has only one dielectric substrate, in order to secure a sufficient capacitance value, the thickness of the dielectric substrate (dielectric layer) is reduced or the area of the dielectric substrate is increased. There is a need to. However, if the dielectric substrate is made thinner, the mechanical strength of the capacitor element decreases. On the other hand, increasing the area of the dielectric substrate leads to an increase in the size of the element. Although it is conceivable to use a multilayer chip capacitor instead of a single plate type capacitor, the multilayer chip capacitor generally has a low Q value and increases insertion loss, and therefore cannot be used for a nonreciprocal circuit device.

  Therefore, in the invention of Patent Document 2 (Japanese Patent Laid-Open No. 2003-179408), a matching capacitor is formed by a capacitor layer (capacitor layer) and a non-capacitor layer (non-capacitor layer) that reinforces the capacitor layer. By making the non-capacitor layer function as a reinforcing layer, the capacitor layer is thinly formed to obtain a large capacitance value and simultaneously ensure mechanical strength.

JP 2004-241944 A JP 2003-179408 A

  By the way, although the inventions described in the above documents both improve the characteristics of the isolator, the element structure described in these documents cannot eliminate the error in the capacitance value of the capacitor caused by the manufacturing process.

  That is, when a capacitor is formed using a dielectric substrate, when an electrode pattern is printed on the substrate surface or each dielectric sheet constituting the laminated substrate is laminated, it is opposed by pattern printing deviation or lamination deviation between sheets. In some cases, the electrodes do not accurately overlap with each other, causing a positional shift. For this reason, the capacitance value of the capacitor formed by both electrodes may deviate from the design value that should be originally obtained, and the capacitance value may vary.

  Such an error in the capacitance value is particularly desirable in the isolator as described above, since the matching capacitor greatly affects the electrical characteristics of the isolator. Furthermore, it is not preferable in terms of characteristics of the electronic component that a capacitance error occurs not only in the isolator but also in other various electronic components including a capacitor.

  Therefore, an object of the present invention is to reduce an error in the capacitance of the capacitor due to the positional deviation between the electrodes provided on the multilayer substrate.

  In order to solve the above-described problems and achieve the object, a capacitor element according to the present invention includes a first electrode including two or more capacitive electrodes that are arranged at intervals in the thickness direction of the multilayer substrate and are electrically connected to each other. And a second electrode that is disposed between two of the two or more capacitive electrodes adjacent to each other in the thickness direction of the multilayer substrate and forms a capacitance between the first electrode and the second electrode. In the capacitor element, the second electrode includes at least two capacitor electrodes that are spaced apart from each other in the thickness direction of the multilayer substrate and are electrically connected to each other.

  An electrode on one side forming a capacitance (capacitor) is composed of a plurality of (for example, two) electrodes electrically connected (for example, via holes), and a capacitance is formed between the plurality of electrodes. A capacitor may be formed in the substrate as a structure sandwiching the electrode on the other side (hereinafter such a structure is referred to as a plug-in type). On the other hand, when a capacitor is formed using a multilayer substrate, the electrodes may be misaligned due to electrode pattern printing misalignment or dielectric sheet stacking misalignment, resulting in an error (variation) in the capacitance value of the capacitor. is there.

  The present inventor analyzed the electric field strength of the electrodes provided in the multilayer substrate in various ways to reduce the variation in the capacitance value, and based on this, the capacitor in the multilayer substrate, in particular, the plug-in capacitor It came to devise the electrode structure which reduces the dispersion | variation in a capacity | capacitance.

  That is, according to the present invention, the second electrode capacitive electrode sandwiched between two capacitive electrodes included in the first electrode in the plug-in capacitor is constituted by a plurality of electrodes electrically connected to each other.

  In an existing plug-in capacitor, one electrode included in the other electrode (second electrode) forming the capacitor is between one set of electrodes included in one electrode (first electrode) forming the capacitor. The present inventor confirmed from the above analysis that the electric field concentrates on the electrode sandwiched (in this structure, a stronger electric field is generated compared to the other electrodes).

  On the other hand, according to the structure of the present invention in which a plurality of the sandwiched electrodes are provided, the concentration of the electric field on the sandwiched electrodes is alleviated, and the electrodes are displaced due to stacking displacement or printing displacement. Even in this case, the influence is reduced, and the capacitance fluctuation of the capacitor can be suppressed to a small value. This point will be further described later with reference to the drawings.

  In the capacitor element of the present invention, the capacitance between the first electrode and the second electrode in which the capacitance is formed so that the interval between the two capacitance electrodes included in the second electrode is opposed to each other. It is preferable to arrange each electrode so as to be larger than the distance between them.

  When one of the electrodes sandwiched (capacitance electrode included in the second electrode) is displaced, an electrode for forming a capacitor (one of the two capacitance electrodes included in the first electrode) A capacitor is formed between the other electrode (the other electrode of the two capacitor electrodes included in the first electrode) that is not originally intended to form a capacitor, and the capacitance value of the capacitor is thereby reduced. This is to prevent fluctuations from occurring.

  The nonreciprocal circuit device according to the present invention includes an input terminal for inputting a signal, an output terminal for outputting a signal, a magnetic rotor provided between the input terminal and the output terminal, and the magnetic rotor. A nonreciprocal circuit device comprising a magnet for applying a DC magnetic field, and one or more matching capacitors, one end of which is electrically connected to the magnetic rotor and the other end of which is electrically connected to the ground, At least one of the matching capacitors is a capacitor element according to the present invention.

  In a non-reciprocal circuit element (for example, an isolator), a matching capacitor plays an important role in determining the electrical characteristics of the element. However, as described above, if the capacitor element of the present invention is used as a matching capacitor, Thus, a non-reciprocal circuit device having good electrical characteristics with less capacitance error of the matching capacitor can be configured.

  The nonreciprocal circuit element includes, for example, a circulator in addition to an isolator. The capacitor element according to the present invention may be configured as a single element of a capacitor or may be included in various electronic components / circuit modules other than the non-reciprocal circuit element.

  According to the present invention, it is possible to reduce an error in the capacitance of the capacitor due to the positional deviation between the electrodes provided on the multilayer substrate.

  Other objects, features, and advantages of the present invention will be clarified by the following description of the embodiments of the present invention described with reference to the drawings. Prior to the description of the embodiments, conventional plug-in electrodes First, a capacitor element having a structure will be described, and then an embodiment of the present invention will be described in comparison with the element. In each figure, the same numerals indicate the same or corresponding parts.

  FIG. 1 shows an example of a conventional capacitor element having a plug-in electrode structure. As shown in the figure, this capacitor element has a built-in capacitor in a multilayer substrate having eight wiring layers including the front and back surfaces of the substrate, and these wiring layers are arranged in order from the substrate surface to the substrate back surface. When the first layer (substrate surface) L1, the second layer L2, the third layer L3,..., The eighth layer (back surface of the substrate) L8, the capacitor includes the capacitive electrode 14 provided on the third layer L3, One electrode of the capacitor (first electrode) is constituted by the capacitor electrode 11 provided in the fifth layer L5 that is electrically connected to the capacitor electrode 14 through the via hole V (hereinafter simply referred to as via) and has substantially the same potential. The capacitor electrode 21 provided on the fourth layer L4 and the capacitor electrode 24 provided on the sixth layer L6 electrically connected to the capacitor electrode 21 through the via V constitute the other electrode (second electrode) of the capacitor. Is.

  The capacitor element further includes a capacitor electrode of the fourth layer L4 such that a capacitor electrode 21 of the fourth layer L4 is interposed between the capacitor electrode 14 of the third layer L3 and the capacitor electrode 11 of the fifth layer L5. 21 and the capacitive electrode 24 of the sixth layer L6 are arranged so that the capacitive electrode 11 of the fifth layer L5 is sandwiched between them. More specifically, the capacitive electrode 14 of the third layer L3 and the capacitive electrode 11 of the fifth layer L5 are electrically connected by a via V on one end side of these electrodes, and the other end of the electrode not provided with the via V It arrange | positions so that the capacity | capacitance electrode 21 of the 4th layer L4 may be inserted from the part side. Similarly, for the capacitive electrode 21 of the fourth layer L4 and the capacitive electrode 24 of the sixth layer L6, these electrodes are electrically connected by a via V on one end side, and the other end of the electrode not provided with the via V is provided. The capacitor electrode 11 of the fifth layer L5 is inserted from the part side.

  Capacitance electrodes 11 and 21 (hereinafter referred to as insertion electrodes) sandwiched between these electrodes are opposite electrodes (first electrode or second electrode) that are adjacent to each other via a dielectric layer (insulating layer). Thus, between the capacitive electrode 14 of the third layer L3 and the capacitive electrode 21 of the fourth layer L4, between the capacitive electrode 21 of the fourth layer L4 and the capacitive electrode 11 of the fifth layer L5, and Capacitances are respectively formed between the capacitive electrode 11 of the fifth layer L5 and the capacitive electrode 24 of the sixth layer L6. External electrodes 25 and 15 are provided on the substrate surface (first layer) L1 and the substrate back surface (eighth layer) L8, respectively. The external electrodes 25 and 15 are connected to the first electrode and the first electrode via vias V, respectively. Two electrodes are connected to each other.

  On the other hand, FIG. 2 is a sectional view showing a capacitor element according to an embodiment of the present invention. In the element of this embodiment, a capacitor is built in a laminated substrate having eight wiring layers L1 to L8 as in the conventional capacitor element, but the first electrode which is one electrode of the capacitor is provided. The capacitor electrodes 14, 12, and 13 are provided on the second layer L2, the fifth layer L5, and the sixth layer L6 that are electrically connected to each other by the vias V, respectively, The second electrode forming the capacitor is composed of capacitive electrodes 22, 23, 24 provided on the third layer L3, the fourth layer L4, and the seventh layer L7, which are electrically connected to each other by the via V, respectively. It is.

  Of these capacitive electrodes, the electrodes 22 and 23 of the third layer L3 and the fourth layer L4 belonging to the second electrode are placed between the electrodes 14 and 12 of the second layer L2 and the fifth layer L5 belonging to the first electrode. The electrodes are arranged so as to be sandwiched and the end positions of the electrodes are aligned (so that one of the electrodes does not protrude), and the electrodes 12 of the fifth layer L5 and the sixth layer L6 belonging to the first electrode, 13 is arranged so as to be sandwiched between the electrodes 23 and 24 of the fourth layer L4 and the seventh layer L7 belonging to the second electrode and so that the end positions thereof are also aligned, whereby the second layer Between the electrode 14 of the L2 and the electrode 22 of the third layer L3, between the electrode 23 of the fourth layer L4 and the electrode 12 of the fifth layer L5, and between the electrode 13 of the sixth layer L6 and the electrode of the seventh layer L7 A capacitance was formed between each of them.

  That is, in the present embodiment, the first electrode and the second electrode capacitive electrode have the same insertion structure as the capacitor element shown in FIG. 1, but are inserted between the counterpart electrodes forming the capacitor. The electrodes 11a and 21a are constituted by two electrodes 12, 13; 22, 23 which are adjacent to each other in the thickness direction of the substrate and are connected to each other by vias V. The insertion electrodes 11a (12, 13) and the insertion electrodes 21a (22, 23) are preferably configured so that their end positions are aligned as in the present embodiment. It is not necessary to completely align the end portions of the insertion electrodes as in the embodiment, and a structure in which any one of the electrodes protrudes is within the scope of the present invention.

  Furthermore, in this embodiment, the interval t0 between the two electrodes 12, 13; 22, 23 constituting the insertion electrodes 11a, 21a is made larger than the interval t1 between the electrodes forming the capacitance. This is because when the electrodes in the insertion electrode are relatively displaced and the tip position of the electrode is shifted (one of the electrodes protrudes in the left-right direction), This is to prevent a capacitance from being formed between the capacitor and the capacitance value of the capacitor. More specifically, for example, when the electrode 22 of the third layer L3 is displaced to the left in the figure, between this electrode 22 and the electrode 12 of the fifth layer L5 that is not originally scheduled for capacitance formation. Although capacitive coupling may occur, the capacitance formed unnecessarily can be reduced by widening the interval t0 between the insertion electrodes.

The inventor has analyzed the electric field strength of the capacitor element having the plug-in structure as described above. FIG. 3 and FIG. 4 show the analysis results. FIG. 3 shows the case where there is one insertion electrode 11 (conventional structure), and FIG. 4 shows that the insertion electrode 21a is divided into two electrodes 22 and 23. This is the case (structure of the present application). In these drawings, the hatched region has a field intensity of less than 5 × 10 ⁶ [V / m], and the shaded region has a field strength of 5 × 10 ⁶ [V / m] or more. The regions where the portions less than × 10 ⁶ [V / m] are blacked out indicate portions where the electric field strength is 7 × 10 ⁶ [V / m] or more.

  As is clear from these figures, in the conventional structure (FIG. 3) with one insertion electrode 11, the electric field concentrates on the insertion electrode 11 and a stronger electric field is generated than the other electrodes. I understand. On the other hand, in the structure (FIG. 4) based on this invention which comprised the insertion electrode 21a by the two electrodes 22 and 23, concentration of the electric field to the insertion electrode 21a is relieve | moderated, and the electric field of the said insertion electrode 21a is It can be seen that the strength is suppressed to the same level as the other electrodes.

  Therefore, in the conventional element structure shown in FIG. 1, since the electric field concentrates on the insertion electrodes 11 and 21 forming the capacitance, the electrodes 11 and 21 or the electrodes 14 and the counterpart electrode 14 forming the capacitance are formed. , 24 cause a displacement, the capacity variation increases. On the other hand, according to the element structure of this embodiment shown in FIG. 2 above, since all the electrodes forming the capacitance, including the insertion electrodes 11a and 21a, have the same low electric field strength, the capacitance variation due to the displacement is caused. It can be kept small.

  The arrangement structure of the electrodes is not limited to the example shown in FIG. 2 and can take various forms. For example, FIG. 5 is a schematic diagram showing an arrangement example of electrodes in the present invention. In each figure, horizontal lines indicate electrodes forming capacitors, and vertical lines indicate vias connecting the electrodes. As shown in this figure, in the present invention, only one of the first electrode and the second electrode may be provided with an insertion electrode (for example, (a), (b), (d) in the figure), Both the electrode and the second electrode may be provided with insertion electrodes (for example, (c) and (e) in the figure). Further, two or more insertion electrodes can be provided on one or both of the first electrode and the second electrode (for example, (d) and (e) in the figure). Furthermore, in the above-described embodiment, the external electrode for the first electrode and the external electrode for the second electrode are provided on the opposite surfaces of the substrate, respectively, but these external electrodes are provided on the same surface (substrate surface or back surface). ) May be provided. In this case, the vias connected from the first and second electrodes to the external electrode extend in the same direction as shown in FIG.

  FIG. 6 is a circuit diagram showing a non-reciprocal circuit device (isolator) according to another embodiment of the present invention. This isolator is similar to conventionally known isolators in that an input terminal 31 to which a signal is input, an output terminal 32 from which a signal is output, and a magnetic rotor provided between the input terminal 31 and the output terminal 32. 34, a magnet (not shown) for applying a DC magnetic field to the magnetic rotor 34, a termination resistor 38 connected to the termination terminal 33, one end electrically connected to the magnetic rotor 34 and the other end Unlike the conventional isolator, the matching capacitors 35 to 37 are configured by the capacitor element according to the above embodiment, which includes three matching capacitors 35, 36, and 37 that are electrically connected to the ground. .

  In the isolator, the matching capacitors 35 to 37 play an important role in determining the frequency characteristics of the isolator. As described above, if the capacitor element of the present embodiment is used as the matching capacitors 35 to 37, the matching capacitors 35 to 37 are matched. It is possible to construct an isolator having good electrical characteristics with little capacitance error of the capacitors 35 to 37 for use.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, It is clear to those skilled in the art that a various change can be made within the range as described in a claim. . For example, the type of substrate (organic multilayer substrate, LTCC or other inorganic ceramic multilayer substrate), the number of laminated layers, insulating layers and electrode constituent materials, substrate / electrode formation methods (subtractive method, semi-additive method, full The additive method is not particularly limited. Further, the present invention can be widely applied to various electronic components / functional modules including a capacitor on a substrate, in addition to a single element of a capacitor, a nonreciprocal circuit device such as an isolator or a circulator.

It is sectional drawing which shows an example of the capacitor | condenser element which has the conventional insertion type electrode structure. It is sectional drawing which shows the capacitor | condenser element which concerns on one Embodiment of this invention. It is a figure which shows the electric field strength distribution in the capacitor | condenser element which has the conventional insertion-type electrode structure. It is a figure which shows the electric field strength distribution in the capacitor | condenser element which has a plug-in type electrode structure to which this invention is applied. It is a schematic diagram which shows the example of arrangement | positioning of the electrode in the capacitor | condenser element of this invention. It is a circuit diagram showing a nonreciprocal circuit device (isolator) according to an embodiment of the present invention.

Explanation of symbols

11, 21, 11a, 21a Insertion electrode 12, 13, 14, 22, 23, 24 Capacitance electrode 15, 25 External electrode 31 Input terminal 32 Output terminal 33 Termination terminal 34 Magnetic rotor 35, 36, 37 Matching capacitor L1 ~ L8 Wiring layer V Via hole

Claims (3)

A first electrode including two or more capacitive electrodes arranged at intervals in the thickness direction of the multilayer substrate and electrically connected to each other;
A capacitor comprising a second electrode that is arranged between two capacitive electrodes adjacent to each other in the thickness direction of the multilayer substrate among the two or more capacitive electrodes and forms a capacitance between the first electrode and the first electrode. An element,
The capacitor element is characterized in that the second electrode includes at least two capacitor electrodes arranged at an interval in the thickness direction of the multilayer substrate and electrically connected to each other. The interval between the two capacitance electrodes included in the second electrode is larger than the interval between the capacitance electrode of the first electrode and the capacitance electrode of the second electrode, which are formed so as to face each other. The capacitor element according to claim 1. An input terminal to which a signal is input;
An output terminal for outputting a signal;
A magnetic rotor provided between the input terminal and the output terminal;
A magnet for applying a DC magnetic field to the magnetic rotor;
One or more matching capacitors having one end electrically connected to the magnetic rotor and the other end electrically connected to ground;
A non-reciprocal circuit device comprising:
3. A nonreciprocal circuit device, wherein at least one of the matching capacitors is the capacitor device according to claim 1 or 2.

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