JP4600082B2 - Multilayer composite electronic components - Google Patents

Description

  The present invention relates to a multilayer composite electronic component, and more particularly to a multilayer composite electronic component used for a noise filter or the like.

  In the power supply line of an IC, noise is generally removed by connecting a bypass capacitor to the ground. By the way, when a printed circuit board having a substantially entire surface covered with a power electrode pattern or a ground electrode pattern is used for high-density mounting, a resonance phenomenon occurs between the power source and the ground. When a resonance phenomenon occurs, radiation noise is generated, and therefore it is necessary to suppress the resonance phenomenon.

  However, when a multilayer ceramic capacitor having a small equivalent series resistance (ESR) of several mΩ is used as a bypass capacitor, the self-resonant frequency is about 1 to 100 MHz, and the impedance in this frequency band is reduced. As a result, the resonance phenomenon occurring in the 1 to 100 MHz band cannot be suppressed.

  As a general measure, it is known that a resonance phenomenon can be suppressed by connecting a resistor in series to a multilayer ceramic capacitor. For this reason, a multilayer ceramic capacitor as described in Patent Document 1 has been proposed. This capacitor constitutes a circuit in which a main capacitor and a resistor are connected in series in a component by allowing the external electrode to conduct with the capacitor electrode through a resistance film.

However, since the resistor has a constant impedance regardless of the frequency, simply connecting the resistors in series impairs the noise removal effect in a frequency band away from the self-resonant frequency of the multilayer ceramic capacitor. Was.
Japanese Utility Model Publication No. 62-184728

  SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer composite electronic component having a high impedance in the 1 to 100 MHz band in which a resonance phenomenon is likely to occur and a low impedance in a high frequency band (100 MHz or higher) of noise components.

In order to achieve the above object, a multilayer composite electronic component according to the present invention includes a multilayer body configured by stacking a plurality of ceramic layers, a main capacitor configured by a plurality of capacitor electrodes built in the multilayer body, In a multilayer composite electronic component formed at an end of a multilayer body and having a plurality of external electrodes electrically connected to the capacitor electrode, at least one of the external electrodes is electrically connected to the capacitor electrode through a dielectric resistance film. Is formed, and an RC parallel circuit is formed by a dielectric resistance film between the external electrode and the capacitor electrode, the main capacitor and the RC parallel circuit are electrically connected in series, and the multilayer composite electronic component penetrates through three terminals. a capacitor, the capacitor electrode is composed of a signal through electrodes and the ground through-electrode, the dielectric resistance film is connected to the through electrode the ground, dielectric resistance film car When the film thickness after curing is 0.01 mm or more and less than 0.03 mm, the carbon content after curing is 4 to 15% by volume. When the film thickness after curing is 0.03 mm or more and less than 0.05 mm, the carbon content after curing is set to 6 to 15% by volume, and the film thickness after curing is 0. When the thickness is 0.05 mm or more and less than 0.08 mm, the carbon content after curing is set to 8 to 15% by volume. When the thickness after curing is 0.08 mm or more and 0.10 mm or less, after curing The carbon content of is set to be 10 to 15% by volume . A base electrode may be further disposed between the dielectric resistance film and the capacitor electrode.

  According to the present invention, since the RC parallel circuit by the dielectric resistance film is formed between the external electrode and the capacitor electrode, and the main capacitor and the RC parallel circuit are electrically connected in series, the frequency band is relatively low. (Under 100 MHz) functions as a series circuit of a main capacitor and a resistor. In this circuit, a voltage fluctuation suppressing effect by the main capacitor and a resonance suppressing effect by the resistance are recognized. Therefore, it is possible to suppress voltage fluctuations in the power supply line and to suppress a resonance phenomenon between the power supply line and the ground.

  On the other hand, in the relatively high frequency band (less than 100 MHz), the impedance of the capacitor of the RC parallel circuit is lowered, so that the characteristics are close to those of the capacitor alone, and the high-frequency noise that has propagated through the propagation of the harmonics of the signal line is effectively reduced. Can be removed. This effect is more advantageous for a three-terminal feedthrough capacitor because the multilayer composite electronic component having a smaller residual series inductance is manifested to a higher frequency band.

  Embodiments of a multilayer composite electronic component according to the present invention will be described below with reference to the accompanying drawings.

(First embodiment, FIGS. 1 to 9)
As shown in FIG. 1, a three-terminal multilayer ceramic capacitor 1 is composed of a ceramic green sheet 2 provided with a signal through electrode 3 and a ground through electrode 4 respectively, and an outer layer ceramic green sheet 2 provided with no conductor pattern in advance. It is configured.

  The ceramic green sheet 2 is obtained by adjusting a ceramic slurry by dispersing a dielectric raw material powder mainly composed of barium titanate or the like in a solvent, and forming the ceramic slurry into a sheet shape by a doctor blade method.

  Next, a conductive paste mainly composed of nickel or the like is applied and printed on each ceramic green sheet 2 by screen printing to form the through electrodes 3 and 4. The signal through electrode 3 is provided in a large area on the upper surface of the sheet 2, and the lead-out portion 3 a is exposed on the left and right sides of the sheet 2. Similarly, the ground penetrating electrode 4 is provided in a large area on the upper surface of the sheet 2, and the lead-out portion 4 a is exposed on the near side and the far side of the sheet 2.

  The ceramic green sheets 2 are stacked so that the through electrodes 3 and 4 are alternately arranged. Further, after the ceramic green sheets 2 for the outer layer are arranged on the upper and lower sides, they are pressure-bonded to form a laminated body block. The laminated body block is cut into a predetermined size and then fired integrally. Thereby, the laminated body 10 shown in FIG. 2 is obtained.

  Next, as shown in FIG. 3, base electrodes 11 a and 11 b that respectively cover the lead portions 3 a of the signal through electrode 3 exposed on both side surfaces of the multilayer body 10 are formed. The base electrodes 11a and 11b are formed by applying and baking a conductive paste mainly composed of copper in a band shape.

  Next, as shown in FIG. 4, carbon resistance films (dielectric resistance films) 12 a and 12 b are formed to cover the lead portions 4 a of the ground through electrodes 4 exposed on both end faces of the laminate 10. The carbon resistance films 12a and 12b are formed by applying and curing a thermosetting carbon resistance paste made of carbon powder and organic resin (phenol resin).

  Thereafter, as shown in FIG. 5, a plating film 15 is formed on the base electrodes 11a and 11b and the carbon resistance films 12a and 12b in the order of nickel and tin by ordinary electrolytic plating, and the signal external electrodes 21a, 21b and ground external electrodes G1 and G2.

  In addition, when it is difficult to attach electrolytic plating on the carbon resistance films 12a and 12b, the surface of the carbon resistance films 12a and 12b is roughened, or the chemical state of the surfaces of the carbon resistance films 12a and 12b is changed. Improve sexiness. Alternatively, a method of applying a conductive paste to the surface of the carbon resistance paste, or a method of attaching metal powder or the like to the surface of the carbon resistance paste may be employed. Alternatively, a base electrode may be formed under the carbon resistance films 12a and 12b, and the base electrode may be disposed between the carbon resistance films 12a and 12b and the ground through electrode 4. As a result, a capacitor is easily formed by the carbon resistance films 12a and 12b, and the capacitance of the RC parallel circuit can be finely adjusted.

  The signal external electrodes 21 a and 21 b are electrically connected to one lead portion 3 a and the other lead portion 3 a of the signal through electrode 3, respectively. The ground external electrodes G1 and G2 are electrically connected to one lead portion 4a and the other lead portion 4a of the ground through electrode 4 via carbon resistance films 12a and 12b, respectively.

  The organic resin used for the carbon resistance film (dielectric resistance film) is not limited to the thermosetting phenol resin (relative dielectric constant 5 to 8) used in the first embodiment or the second embodiment described below. For example, a thermosetting resin such as an epoxy resin (relative dielectric constant 4 to 4.5) can be used. The relative permittivity of the organic resin is as small as 10 or less, and it is difficult to obtain the relative permittivity required for the dielectric resistance curtain only by the relative permittivity of the resin itself. A high relative dielectric constant can be obtained by uniformly dispersing carbon particles in the organic resin and allowing the organic resin to enter minute gaps between the carbon particles.

  In the three-terminal multilayer ceramic capacitor 1 having the above configuration, as shown in FIG. 6, the carbon resistance films 12a and 12b formed at the end of the multilayer body 10 form an RC parallel circuit. That is, an RC parallel circuit including the carbon resistance films 12a and 12b is formed between the ground external electrodes G1 and G2 and the ground through electrode 4 respectively. The main capacitor C constituted by the signal through electrode 3 and the ground through electrode 4 incorporated in the laminate 10 is electrically connected in series with the RC parallel circuit including the carbon resistance films 12a and 12b. .

  FIG. 7 is an electrical equivalent circuit diagram of the three-terminal multilayer ceramic capacitor 1. In FIG. 7, a symbol C indicates a main capacitor, Ls indicates a residual series inductance, C ′ indicates a capacitor of an RC parallel circuit, and R indicates a resistance of the RC parallel circuit.

  The three-terminal multilayer ceramic capacitor 1 has an insertion loss (IL) characteristic as schematically shown in FIG. 8 because the main capacitor and the RC parallel circuit are electrically connected in series. That is, the characteristic that the attenuation pole P is formed near 1 GHz higher than the self-resonance frequency of the main capacitor is obtained. A dotted line 31 is an insertion loss component by the main capacitor C, and moves downward when the capacitance value of the main capacitor C increases, and moves upward when the capacitance value decreases. A dotted line 32 is an insertion loss component due to the resistor R, and moves upward when the resistance value of the resistor R increases, and moves downward when it decreases. A dotted line 33 is an insertion loss component due to the capacitor C ′, and moves downward when the capacitance value of the capacitor C ′ increases, and moves upward when it decreases. A dotted line 34 is an insertion loss component due to the residual series inductance Ls, and moves upward when the value of the residual series inductance Ls increases, and moves downward when it decreases.

  As can be seen from FIG. 8, it functions as a series circuit of the main capacitor C and the resistor R in a band having a relatively low frequency (less than 100 MHz). In this circuit, a voltage fluctuation suppressing effect by the main capacitor C and a resonance suppressing effect by the resistor R are recognized. Therefore, voltage fluctuations in the power supply line can be suppressed, and a resonance phenomenon between the power supply line and the ground can be suppressed with a capacitor having a small residual series inductance Ls. This effect is manifested when the resistor R is connected in series with the main capacitor C (see the region I). However, when the capacitance value of the main capacitor C is small, the value of the residual series inductance Ls is large, or the resistance value of the resistor R is small, the region I becomes small, and the above-described effect is hardly exhibited. .

  On the other hand, in the band having a relatively high frequency (100 MHz or more), the impedance of the capacitor C ′ of the RC parallel circuit is lowered, so that it functions as a series circuit of the main capacitor C and the capacitor C ′. In this circuit, it is possible to effectively remove high-frequency noise that has entered through the propagation of harmonics of the signal line. This effect does not appear when only the resistor R is connected in series to the main capacitor C (see the part of region II). However, when the capacitance value of the capacitor C ′ is small, or when the value of the residual series inductance Ls is large, or when the resistance value of the resistor R is small, the portion of the region II becomes small and the above-described effect is hardly exhibited. . Further, this effect is more advantageous for a three-terminal feedthrough capacitor because a multilayer composite electronic component having a smaller residual series inductance Ls is manifested up to a higher frequency band.

  FIG. 9 is a graph showing insertion loss characteristics of the three-terminal multilayer ceramic capacitor 1 (see the solid line 35). For comparison, FIG. 9 also shows a graph showing insertion loss characteristics of a three-terminal multilayer ceramic capacitor that does not have an RC parallel circuit (see solid line 36).

  In order to form a more optimal RC parallel circuit, a sample of the three-terminal multilayer ceramic capacitor 1 is prepared by changing the carbon content after curing of the carbon resistance films 12a and 12b and the film thickness T after curing (see FIG. 6). And the characteristics were evaluated. Here, the component size was 2.0 mm long × 1.25 mm wide × 0.85 mm thick. The evaluation results are shown in Tables 1 and 2.

  By the way, the voltage fluctuation suppression effect by the main capacitor C and the resonance suppression effect by the resistor R in the relatively low frequency band (less than 100 MHz) can be obtained when the insertion loss (1 MHz) is 10 dB or more. Therefore, Table 1 and Table 2 summarize the insertion loss at 1 MHz (see Table 3). Further, the noise removal effect in a relatively high frequency band (100 MHz or higher) is obtained when the insertion loss at 1 GHz minus the insertion loss at 1 MHz is 2 dB or higher. Therefore, Table 1 and Table 2 summarize the values obtained by subtracting the insertion loss at 1 MHz from the insertion loss at 1 GHz (see Table 4).

  From Tables 3 and 4, a voltage fluctuation suppressing effect and a resonance suppressing effect are obtained in a relatively low frequency band (less than 100 MHz), and a noise removing effect is obtained in a relatively high frequency band (100 MHz or higher). It can be seen that the relationship between the carbon content and the film thickness T shown in Table 5 is necessary in order to achieve this.

  From Table 5, the optimum conditions for the carbon resistance films 12a and 12b are as follows.

  (1) When the film thickness after curing is 0.01 mm or more and less than 0.03 mm, the carbon content after curing needs to be set to 4 to 15% by volume.

  (2) When the film thickness after curing is 0.03 mm or more and less than 0.05 mm, it is necessary to set the carbon content after curing to be 6 to 15% by volume.

  (3) When the film thickness after curing is 0.05 mm or more and less than 0.08 mm, it is necessary to set the carbon content after curing to 8 to 15% by volume.

  (4) When the film thickness after curing is 0.08 mm or more and 0.10 mm or less, it is necessary to set the carbon content after curing to 10 to 15% by volume.

(Second embodiment, FIGS. 10 to 12)
As shown in FIG. 10, the two-terminal multilayer ceramic capacitor 41 is composed of a ceramic green sheet 42 provided with capacitor electrodes 43 and 44, an outer layer ceramic green sheet 42 not previously provided with a conductor pattern, and the like.

  The capacitor electrode 43 is provided in a large area on the upper surface of the sheet 42, and the lead-out portion 43 a is exposed on the front side of the sheet 42. Similarly, the capacitor 44 is provided in a large area on the upper surface of the sheet 42, and the lead-out portion 44 a is exposed on the back side of the sheet 42.

  The ceramic green sheets 42 are stacked so that the capacitor electrodes 43 and 44 are alternately arranged. Further, after the ceramic green sheets 42 for outer layers are arranged on the upper and lower sides, they are pressure-bonded to form a laminated body block. The laminated body block is cut into a predetermined size and then fired integrally. Thereby, the laminated body 50 shown in FIG. 11 is obtained.

  Next, carbon resistance films (dielectric resistance films) 52a and 52b are formed to cover the lead portions 43a and 44a of the capacitor electrodes 43 and 44 exposed on both end faces of the multilayer body 50, respectively. The carbon resistance films 52a and 52b are formed by applying and curing a thermosetting carbon resistance paste made of carbon powder and organic resin (phenol resin).

  Thereafter, on the carbon resistance films 52a and 52b, plating films are formed in the order of nickel and tin by ordinary electrolytic plating to form external electrodes 53a and 53b.

  A base electrode may be formed under the carbon resistance films 52a and 52b, and the base electrode may be disposed between the carbon resistance films 52a and 52b and the capacitor electrodes 44 and 43, respectively. This facilitates the formation of capacitors by the carbon resistance films 52a and 52b, and enables fine adjustment of the capacity of the RC parallel circuit.

  The external electrodes 53a and 53b are electrically connected to the lead portion 44a of the capacitor electrode 44 and the lead portion 43a of the capacitor electrode 43 via the carbon resistance films 52a and 52b, respectively.

  In the two-terminal multilayer ceramic capacitor 41 having the above configuration, the carbon resistance films 52a and 52b formed at the end of the multilayer body 50 form an RC parallel circuit. That is, an RC parallel circuit is formed by the carbon resistance films 52a and 52b between the external electrodes 53a and 53b and the capacitor electrodes 44 and 43, respectively. And the main capacitor C comprised by the capacitor electrodes 43 and 44 incorporated in the laminated body 50 and the RC parallel circuit by the carbon resistance films 52a and 52b are electrically connected in series. FIG. 12 is an electrical equivalent circuit diagram of the two-terminal multilayer ceramic capacitor 41.

  Since the two-terminal multilayer ceramic capacitor 41 electrically connects the main capacitor C and the RC parallel circuit in series, it functions as a series circuit of the main capacitor C and the resistor R in a relatively low frequency band (less than 100 MHz). . In this circuit, a voltage fluctuation suppressing effect by the main capacitor C and a resonance suppressing effect by the resistor R are recognized. Therefore, voltage fluctuations in the power supply line can be suppressed, and a resonance phenomenon between the power supply line and the ground can be suppressed with a capacitor having a small residual series inductance Ls.

  On the other hand, in the band having a relatively high frequency (100 MHz or more), the impedance of the capacitor C ′ of the RC parallel circuit is lowered, so that it functions as a series circuit of the main capacitor C and the capacitor C ′. In this circuit, it is possible to effectively remove high-frequency noise that has entered through the propagation of harmonics of the signal line.

  In order to form a more optimal RC parallel circuit, a sample of the two-terminal multilayer ceramic capacitor 41 is prepared by changing the carbon content after curing of the carbon resistance films 52a and 52b and the film thickness T after curing, and the characteristics are evaluated. did. The evaluation results are shown in Tables 6 and 7.

  By the way, the voltage fluctuation suppression effect by the main capacitor C and the resonance suppression effect by the resistor R in the relatively low frequency band (less than 100 MHz) can be obtained when the insertion loss (1 MHz) is 10 dB or more. Therefore, Table 6 and Table 7 summarize the insertion loss at 1 MHz (see Table 8). Further, the noise removal effect in a relatively high frequency band (100 MHz or higher) is obtained when the insertion loss at 1 GHz minus the insertion loss at 1 MHz is 2 dB or higher. Therefore, Table 6 and Table 7 summarize the values obtained by subtracting the insertion loss at 1 MHz from the insertion loss at 1 GHz (see Table 9).

  From Table 8 and Table 9, a voltage fluctuation suppressing effect and a resonance suppressing effect are obtained in a relatively low frequency band (less than 100 MHz), and a noise removing effect is obtained in a relatively high frequency band (100 MHz or higher). It can be seen that the relationship between the carbon content and the film thickness T shown in Table 10 is necessary to achieve this.

  From Table 10, the optimum conditions for the carbon resistance films 52a and 52b are as follows.

  (1) When the film thickness after curing is 0.01 mm or more and less than 0.02 mm, it is necessary to set the carbon content after curing to 8 to 10% by volume.

  (2) When the film thickness after curing is 0.02 mm or more and less than 0.03 mm, it is necessary to set the carbon content after curing to 10 to 15% by volume.

  (3) When the film thickness after curing is 0.03 mm or more and less than 0.05 mm, it is necessary to set the carbon content after curing to 15 volume%.

  (4) When the film thickness after curing is 0.05 mm or more and less than 0.06 mm, it is necessary to set the carbon content after curing to 15 to 20% by volume.

  (5) When the film thickness after curing is 0.06 mm or more and 0.10 mm or less, it is necessary to set the carbon content after curing to 20 volume%.

(Other examples)
The multilayer composite electronic component according to the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist thereof.

  For example, in the above embodiment, the ceramic green sheets are stacked to form a laminated body. However, the laminated body may be formed by a method in which a dielectric paste and a conductive paste are alternately and sequentially applied. .

1 is an exploded perspective view showing an embodiment of a multilayer composite electronic component according to the present invention. FIG. 2 is an external perspective view showing a manufacturing process following FIG. 1. FIG. 3 is an external perspective view showing a manufacturing process following FIG. 2. FIG. 4 is an external perspective view showing a manufacturing process following FIG. 3. FIG. 5 is an external perspective view illustrating a manufacturing process subsequent to FIG. 4. The schematic diagram which shows the vertical cross section of VI-VI of FIG. FIG. 6 is an electrical equivalent circuit diagram of the multilayer composite electronic component shown in FIG. 5. 6 is a graph schematically showing insertion loss characteristics of the multilayer composite electronic component shown in FIG. 6 is a graph showing insertion loss characteristics of the multilayer composite electronic component shown in FIG. 5. The disassembled perspective view which shows another Example of the multilayer composite electronic component which concerns on this invention. FIG. 11 is an external perspective view illustrating a manufacturing process subsequent to FIG. 10. FIG. 12 is an electrical equivalent circuit diagram of the multilayer composite electronic component shown in FIG. 11.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,41 ... Multilayer ceramic capacitor 2,42 ... Ceramic green sheet 3 ... Signal through electrode 4 ... Ground through electrode 10, 50 ... Laminated body 12a, 12b, 52a, 52b ... Carbon resistance film 21a, 21b ... Signal outside Electrodes G1, G2 ... Ground external electrodes 43, 44 ... Capacitor electrodes 53a, 53b ... External electrodes C ... Main capacitor C '... Capacitor in RC parallel circuit R ... Resistance in RC parallel circuit

Claims (2)

A laminated body constituted by stacking a plurality of ceramic layers, a main capacitor constituted by a plurality of capacitor electrodes built in the laminated body, and formed at an end of the laminated body, and electrically connected to the capacitor electrode In a multilayer composite electronic component having a plurality of external electrodes connected to
At least one of the external electrodes is electrically connected to the capacitor electrode through a dielectric resistance film, and an RC parallel circuit is formed by the dielectric resistance film between the external electrode and the capacitor electrode; Electrically connecting the main capacitor and the RC parallel circuit in series;
The multilayer composite electronic component is a three-terminal through capacitor, the capacitor electrode is composed of a signal through electrode and a ground through electrode, and the dielectric resistance film is connected to the ground through electrode ,
The dielectric resistance film is a carbon resistance film containing carbon powder and an organic resin,
The carbon resistive film is
When the film thickness after curing is 0.01 mm or more and less than 0.03 mm, the carbon content after curing is set to 4 to 15% by volume,
When the film thickness after curing is 0.03 mm or more and less than 0.05 mm, the carbon content after curing is set to be 6 to 15% by volume,
When the film thickness after curing is 0.05 mm or more and less than 0.08 mm, the carbon content after curing is set to 8 to 15% by volume,
When the film thickness after curing is 0.08 mm or more and 0.10 mm or less, the carbon content after curing is set to be 10 to 15% by volume ,
A multilayer composite electronic component characterized by 2. The multilayer composite electronic component according to claim 1, wherein a base electrode is disposed between the dielectric resistance film and the capacitor electrode.

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