JP5292728B2 - Antistatic parts - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrostatic countermeasure component suitable for electrostatic countermeasure in a high-speed differential transmission circuit. <P>SOLUTION: This electrostatic countermeasure component comprises a sintered ceramic body 200 formed with a first resistor 205a electrically connected to a first input external electrode and a first output external electrode, a first varistor 204a electrically connected to the first output external electrode and a ground external electrode, a second resistor 205b electrically connected to a second input external electrode and a second output external electrode, and a second varistor 204b electrically connected to the second output external electrode and the ground external electrode. Thereby, the electrostatic countermeasure component suitable for electrostatic countermeasure in the high-speed differential transmission circuit is obtained which can reduce variation in the differential impedance and which has a favorable transmission characteristic in the high-speed differential transmission circuit and a favorable absorption suppressing effect for an electrostatic pulse. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a static electricity countermeasure component for protecting an electronic device from static electricity.

  Semiconductor devices such as ICs and LSIs are destroyed or deteriorated due to static electricity. In particular, recent semiconductor devices have become vulnerable to static electricity due to miniaturization of wiring patterns accompanying high-speed operation, and the importance of countermeasures against static electricity has been highlighted. Conventionally, as a countermeasure against such static electricity, a method has been used in which a non-linear resistor such as a varistor is provided between a line where static electricity enters and the ground to bypass the static electricity and suppress the voltage applied to the protected device. .

  In addition, with the recent installation of high-speed interfaces such as High Definition Multimedia Interface (HDMI), there is an increasing demand for high transmission quality in signal lines. In such high-speed signal transmission, impedance matching is very important. The capacitance component of the varistor connected to the signal line, when used in a high-speed differential transmission circuit, causes the impedance at this mounting site to drop sharply, causing differential signal waveform distortion such as rise characteristics. . For this reason, in high-speed signal lines, countermeasures against static electricity have been taken using varistors with extremely low capacitance because of the need to reduce the effect on impedance at the transmission speed, but the electrostatic countermeasure function is insufficient. It was something. This is because, generally, the electrostatic capacity of a varistor is closely related to a static electricity countermeasure function, and if the value of the electrostatic capacity is small, electrostatic absorption characteristics and resistance to static electricity are reduced.

Therefore, antistatic parts for high-speed transmission that improve these have been proposed. For example, Patent Document 1 proposes a multilayer chip varistor in which the internal electrode width is set to a predetermined value so that the electrostatic capacity is maintained and the electrostatic capacity is reduced.
JP 2006-41058 A

  However, the above-mentioned multilayer chip varistor has improved static electricity resistance by relaxing the electric field distribution concentrated on the end of the internal electrode. Although it can be improved to some extent, it greatly improves the static electricity resistance of the varistor. It is difficult. That is, an improvement effect that exceeds the trade-off relationship between the electrostatic capacity of the varistor and the electrostatic withstand capability cannot be obtained, and the improvement effect is limited within this relationship range.

  As described above, static electricity countermeasures in high-speed transmission systems have the problem that it is extremely difficult to achieve both electrostatic absorption characteristics and static electricity resistance and transmission characteristics, and there are static electricity countermeasures that protect semiconductor devices, etc. in high-speed transmission circuits from damage due to static electricity. There is a problem that it is insufficient.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a static electricity countermeasure component that has both good transmission characteristics and high static absorption suppression effect in a high-speed differential transmission circuit.

  In order to achieve the above object, the present invention provides a ceramic sintered body provided with first and second input external electrodes, first and second output external electrodes, and a ground external electrode. A first resistor that is electrically connected to the first input external electrode and the first output external electrode is formed in the ceramic sintered body, and the first output external electrode is formed. A first varistor electrically connected to the ground external electrode and a second resistor electrically connected to the second input external electrode and the second output external electrode Forming a second varistor that is electrically connected to the second output external electrode and the ground external electrode, thereby reducing fluctuations in differential impedance. Transmission characteristics are improved. Absorption inhibitory effect on the transmission characteristics and electrostatic pulse in the circuit is both good, in particular, the protection component can be realized suitable for ESD protection in high-speed differential transmission circuit. In addition, a small and highly reliable antistatic component can be realized.

  According to the anti-static component of the present invention, a small and highly reliable anti-static component can be realized, and both the transmission characteristics in the high-speed differential transmission circuit and the absorption suppression effect against the electrostatic pulse are good. It is an anti-static component suitable for static electricity countermeasures in circuits.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

(Embodiment)
Hereinafter, the anti-static component of the present invention will be described using an embodiment. FIG. 1 is a schematic exploded perspective view of a ceramic sintered body in an embodiment of the present invention, and FIG. 2 is an external perspective view of an antistatic component in an embodiment of the present invention.

  1 and 2, 200 is a ceramic sintered body, 201a is a first input external electrode, 201b is a second input external electrode, 202a is a first output external electrode, and 202b is a second output. An external electrode 203, a ground external electrode 204a, a first varistor 204a, a second varistor 204b, a first resistor 205a, and a second resistor 205b.

  As shown in FIGS. 1 and 2, the antistatic component in the present embodiment includes a first sintered external electrode 201a and a ceramic input body 201 having a structure in which a ceramic layer 210 made of a varistor material is laminated and integrated. A second input external electrode 201b, a first output external electrode 202a, a second output external electrode 202b, and a ground external electrode 203 are provided.

  Then, a first resistor 205a electrically connected to the first input external electrode 201a and the first output external electrode 202a is formed inside the ceramic sintered body 200, and the first output output electrode 201a is formed. A first varistor 204a electrically connected to the external electrode 202a and the ground external electrode 203 is formed, and a first varistor electrically connected to the second input external electrode 201b and the second output external electrode 202b is formed. The second resistor 205b is formed, and the second varistor 204b electrically connected to the second output external electrode 202b and the ground external electrode 203 is formed.

  The first resistor 205a is formed inside the ceramic sintered body 200 by connecting the wiring conductor 215a formed in the ceramic layer 210 with the via conductor 225a formed in the via portion of the ceramic layer 210. Both ends of the resistor 205a are drawn out to both side portions of the ceramic sintered body 200. Similarly, the second resistor 205b is formed inside the ceramic sintered body 200 by connecting the wiring conductor 215b formed in the ceramic layer 210 with the via conductor 225b formed in the via portion of the ceramic layer 210. Both ends of the second resistor 205b are formed by being drawn out to both side portions of the ceramic sintered body 200. The first varistor 204a is formed by alternately laminating internal electrodes 214a and internal electrodes 224 with the ceramic layer 210 interposed therebetween, and the internal electrodes 224 are drawn out to the central portion of one side surface of the ceramic sintered body 200. The internal electrode 214a is drawn out to the other side surface portion of the ceramic sintered body 200. The second varistor 204b is formed by alternately laminating internal electrodes 214b and internal electrodes 224 with the ceramic layer 210 interposed therebetween, and the internal electrodes 214b are drawn out to the other side surface portion of the ceramic sintered body 200. .

  Further, one of the first input external electrode 201a and the second resistor 205b formed on one side surface of the ceramic sintered body 200 so as to be electrically connected to one of the first resistors 205a. A second input external electrode 201b formed so as to be electrically connected to the second electrode, and a ground external electrode 203 formed so as to be electrically connected to one of the internal electrodes 224, and the other of the ceramic sintered body 200. The first output external electrode 202a formed to be electrically connected to the other of the first resistor 205a and the internal electrode 214a of the first varistor 204a, and the other of the second resistor 205b And a second output external electrode 202b formed so as to be electrically connected to the internal electrode 214b of the second varistor 204b.

  The circuit of the static electricity countermeasure component in the present embodiment is an equivalent circuit diagram shown in FIG. In FIG. 3, 101a is a first input external electrode, 101b is a second input external electrode, 102a is a first output external electrode, 102b is a second output external electrode, and 103 is a ground external electrode. , 104a are first varistors, 104b is a second varistor, 105a is a first resistor, and 105b is a second resistor.

  Next, a method for manufacturing an antistatic component in one embodiment of the present invention will be described with reference to FIGS.

First, a zinc oxide raw sheet comprising a ceramic powder containing zinc oxide as a main component as a varistor material and Bi ₂ O ₃ as an additive and an organic binder was prepared and prepared. At this time, the thickness of the raw sheet was about 30 μm. This raw sheet becomes the ceramic layer 210 after firing.

  Next, a plurality of the zinc oxide raw sheets are prepared as shown in FIG. 1, and first, via conductors 225a and vias are formed in order to form the first resistor 205a and the second resistor 205b shown in FIG. With respect to the layer on which the conductor 225b is to be provided, a via hole having a diameter of 100 μm was provided by die punching at a predetermined position of each raw zinc oxide sheet. Thereafter, the via hole was filled with an AgPd alloy paste mainly composed of Ag to be the via conductor 225a and the via conductor 225b. After that, as shown in FIG. 1 including these zinc oxide raw sheets, conductors that become the wiring conductors 215a and the wiring conductors 215b by screen printing using AgPd alloy paste on each of the plurality of zinc oxide raw sheets. A layer was formed.

  As shown in FIG. 1, the conductor layers to be the wiring conductor 215a and the wiring conductor 215b have a meander arrangement with the lamination direction as an axis, and the current directions are opposite to each other up and down in the lamination direction. Therefore, the mutual inductance is offset and reduced, and the resistor structure has a small frequency dependency. The conductor layer had a width of about 130 μm and a thickness of about 2 μm after drying. Further, the printed pattern of the conductor layer was a pattern shape in which a large number of the illustrated shapes were arranged vertically and horizontally so as to have the shape shown in FIG.

  Further, in order to form the first varistor 204a and the second varistor 204b shown in FIG. 1, a screen printing method using an AgPd alloy paste on each of a plurality of zinc oxide raw sheets as shown in FIG. Conductive layers to be the internal electrode 214a, the internal electrode 214b, and the internal electrode 224 were formed. Note that the printed pattern of the conductor layer was a pattern shape in which a large number of the illustrated shapes were arranged vertically and horizontally so as to have the shape shown in FIG.

  Next, a zinc oxide raw sheet on which a conductor layer to be the wiring conductor 215a and the wiring conductor 215b is formed, and a zinc oxide raw sheet on which the conductor layer to be the internal electrode 214a, the internal electrode 214b and the internal electrode 224 is formed Lamination and pressurization were performed to obtain a laminate block.

  Next, the laminated body block was cut and separated into a desired size to obtain individual raw chips. This raw chip was heated to about 500 ° C. in the atmosphere to remove the binder, and then heated to about 1100 ° C. in the atmosphere and fired to obtain a sintered body.

  Next, the sintered body was barrel-polished to expose the wiring conductors of the two resistors and the internal electrodes of the two varistors on both side surfaces of the sintered body to obtain the ceramic sintered body 200 of FIG. Subsequently, a thermosetting electrode paste mainly composed of Ag and resin is applied to both side surfaces of the ceramic sintered body 200 and cured at about 300 ° C. to be connected to the wiring conductor 215a of the first resistor 205a. The first input external electrode 201a, the second input external electrode 201b connected to the wiring conductor 215b of the second resistor 205b, the wiring conductor 215a of the first resistor 205a and the inside of the first varistor 204a. A first output external electrode 202a connected to the electrode 214a, a second output external electrode 202b connected to the wiring conductor 215b of the second resistor 205b and the internal electrode 214b of the second varistor 204b, and A ground external electrode 203 connected to the internal electrode 224 of the first varistor 204a and the second varistor 204b was formed. Furthermore, nickel and tin were plated on each with a thickness of about 2 μm, and the antistatic component in the present embodiment shown in FIG. 2 was produced. The produced antistatic component in the present embodiment had a longitudinal dimension of 1.6 mm, a width dimension of 0.8 mm, and a thickness direction dimension of 0.45 mm.

  In addition, as the anti-static component in the present embodiment, the number of wiring conductor layers and the number of via conductor connections are obtained in order to obtain the resistance values of the first resistor 205a and the second resistor 205b. In addition to this, the connection distance between the first resistor 205a and the first varistor 204a and the second resistor 205b and the second resistor are changed. In order to obtain a varistor 204b whose connection distance is changed, the pattern shape of the internal electrode 214a and the internal electrode 214b is changed, and the ceramic sintered body is formed from the portion of the internal electrode 214a and the internal electrode 214b facing the internal electrode 224. The length to the side drawer is changed to 0.25 mm, 1.25 mm, and 2.5 mm in addition to the above three types with 0.1 mm. 3 kinds of things, to produce a total of six types.

  The results of evaluating the electrical characteristics of these six types of anti-static parts in the present embodiment are shown in (Table 1).

  The capacitance (C) and dielectric loss tangent (tan δ) were measured using a digital LCR meter at a measurement frequency of 1 MHz and a measurement voltage of 1.0 Vrms. In Table 1, C1 and tan δ1 are measured values of the first varistor 204a, are values measured between the first output external electrode 202a and the ground external electrode 203, and C2 and tan δ2 are The measured value of the second varistor 204b is a value measured between the second output external electrode 202b and the ground external electrode 203.

  The varistor voltage (V1 mA) is a voltage when a current of 1 mA flows in the varistor. In (Table 1), V1mA1 is a measured value of the first varistor 204a, and the first output external electrode 202a. V1mA2 is a measured value of the second varistor 204b, and is measured between the second output external electrode 202b and the ground external electrode 203. Value.

  The resistance value (Rdc) was measured using a digital LCR meter. In Table 1, Rdc1 is a measured value of the first resistor 205a, a value measured between the first input external electrode 201a and the first output external electrode 202a, and Rdc2 is The measured value of the second resistor 205b is a value measured between the second input external electrode 201b and the second output external electrode 202b.

In addition, the electrical length (EL) is obtained by converting the connection distance between the resistor and the varistor into an electrical length, and (electric length) = (physical length) / (velocity of light) × (dielectric constant of medium) ^1/2 Since the static electricity prevention component in this embodiment is a zinc oxide varistor material, the dielectric constant of the medium is 150, and the physical length is the internal length of the internal electrode 214a and the internal electrode 214b as described above. Since the length from the part facing the electrode 224 to the lead part on the side surface of the ceramic sintered body was 0.25 mm, 1.25 mm, and 2.5 mm, it was calculated from these values by the above formula. In Table 1, EL1 is the electrical length of the connection between the first resistor 205a and the first varistor 204a, and EL2 is the electrical length of the connection between the second resistor 205b and the second varistor 204b. It is long.

  As shown in (Table 1), sample No. In all of 1 to 6, the capacitance (C) was about 1.7 pF, the dielectric loss tangent (tan δ) was about 0.001, and the varistor voltage (V1 mA) was about 40V. The resistance values (Rdc1 and Rdc2) of the samples in which the electrical length (EL) is constant at 4 psec and the resistance value (Rdc) of the resistor is changed are the same as the sample Nos. 1 is 10Ω, and sample No. 1 2 is 15Ω, sample No. Both 3 were 21Ω. Further, the electrical lengths (EL1 and EL2) of the samples in which the resistance value (Rdc) is constant at 21Ω and the electrical length (EL) of the connection between the resistor and the varistor is changed are the same as the sample No. 4 is 10 psec. 5 is 50 psec. Both 6 were 100 psec.

  Table 1 also shows the results of evaluating the electrical characteristics of Comparative Example 1 and Comparative Example 2 used for comparison with the antistatic component of the present embodiment. Comparative Example 1 and Comparative Example 2 are both conventional zinc oxide-based 1005 size chip-type laminated varistors. Comparative Example 1 has a varistor voltage (V1 mA) of about 40 V and a capacitance (C) of about 0.7 pF. Comparative Example 2 has a varistor voltage (V1 mA) of about 40 V and a capacitance (C) of about 1.7 pF.

  Next, since the relationship between the transmission characteristics and the effect of suppressing the absorption of electrostatic pulses is particularly important in the countermeasure against static electricity in the high-speed differential transmission circuit, the electrostatic countermeasure component of this embodiment, Comparative Example 1, and Comparative Example The transmission characteristics and the absorption suppression effect against electrostatic pulses when 2 was used were evaluated.

  First, the sample No. of the present embodiment shown in (Table 1). About the static electricity countermeasure components of 1-6, and the comparative example 1 and the comparative example 2, the transmission characteristic at the time of using for a differential transmission circuit was evaluated.

  The transmission characteristics were evaluated by differential TDR (Time Domain Reflectmetry) as impedance matching evaluation of the differential transmission line. This evaluation was performed by using a TDR oscilloscope, observing the differential impedance when transmitting the evaluation substrate with a waveform rise time (Tr) of 200 psec on the time axis, and measuring the fluctuation (ΔZ) of the differential impedance. The variation (ΔZ) in the differential impedance was the maximum variation from the value of the average differential impedance of the substrate line. An example of the measurement result of the differential impedance variation (ΔZ) is shown in FIG. As shown in FIG. 4, the differential impedance is lowered at a position of about 16 to 17 nsec, that is, a varistor mounting position, and such a fluctuation (ΔZ) of the differential impedance causes a deterioration in signal transmission quality.

  In addition, the used evaluation board is formed on a resin board so that two lines with a characteristic impedance of 50Ω are combined so that a differential impedance obtained by combining these lines is 100Ω, and a GND pattern is formed between the two lines. It is a thing.

  And as an evaluation sample, sample No. of this embodiment of (Table 1). Each of the antistatic parts 1 to 6 and Comparative Examples 1 and 2 were soldered and mounted on the evaluation board for evaluation. The mounting connection state was as follows. For the static electricity countermeasure component of the present embodiment, a part of each of the two lines of the evaluation board is cut, and the first input external electrode 201a and the first output are provided on one line of the cut part. The external external electrode 202a was connected, the second external input electrode 201b and the second external output electrode 202b were connected on the other line, and the external ground electrode 203 was connected to the GND pattern. Further, as for the conventional chip-type multilayer varistors of Comparative Example 1 and Comparative Example 2, two chip-type multilayer varistors are used, and one of the external electrodes of one chip-type multilayer varistor is connected to one line of the evaluation board. The other external electrode is connected to the GND pattern, and one external electrode of the other chip-type multilayer varistor is connected to the other line of the evaluation substrate and the other external electrode is connected to the GND pattern. Connected.

  As an evaluation result, sample No. The measured values of the differential impedance fluctuation (ΔZ) of the antistatic components 1 to 6 and Comparative Examples 1 and 2 are shown in Table 2.

  Subsequently, the sample No. of the present embodiment shown in (Table 1). The static electricity countermeasure parts 1 to 6 and Comparative Examples 1 and 2 were evaluated by conducting an electrostatic test.

  The static electricity test was performed with the circuit shown in FIG. When a predetermined voltage is applied by the power supply 401 with the switch 403 connected, the capacitor box 404 having a capacitance of 150 pF is charged through the resistor 402. Thereafter, the switch 403 is opened and the switch 405 is connected. The charge charged in the capacitor box 404 is applied to the protected device 410 from the resistor 406 through the signal line 408 as an electrostatic pulse.

  Then, as shown in FIG. 5, the first input external electrode 201 a (or the second input external electrode 201 b) is connected to the input side of the signal line 408 as the evaluation sample 409 for the antistatic component of this embodiment. That is, the first output external electrode 202a (or the second output external electrode 202b) is connected to the output side of the signal line 408, that is, the protected device 410 side, and the ground external electrode 203 is connected to the resistor 406 side. Was connected to the ground line 407. For the chip-type multilayer varistors of Comparative Example 1 and Comparative Example 2, as an evaluation sample 409, one external electrode is connected to the input side and the output side of the signal line 408, and the other external electrode is connected to the ground line 407. did.

  Then, the voltage waveform between the signal line 408 immediately before the protected device 410 and the ground line 407 when an electrostatic pulse of 8 kV is applied by the circuit shown in FIG. 5 is measured, and the peak voltage value (Vs) is measured. Accordingly, the effect of suppressing the voltage applied to the protected device 410 by bypassing the electrostatic pulse, that is, the electrostatic countermeasure component of the present embodiment which is the evaluation sample 409 and the electrostatic pulse for the comparative example 1 and the comparative example 2 The absorption inhibitory effect on was evaluated. That is, in the evaluation by this electrostatic test, it can be said that the smaller the peak voltage value (Vs), the greater the absorption suppression effect of the evaluation sample with respect to the electrostatic pulse.

  As an evaluation result by the electrostatic test, the measurement result of the peak voltage value (Vs) of the signal line immediately before the protected device for each evaluation sample is shown in (Table 2). In Table 2, Vs1 is a measured value obtained by connecting and evaluating the first input external electrode 201a and the first output external electrode 202a to the signal line 408, and Vs2 The measured values are obtained by connecting and evaluating the input external electrode 201b and the second output external electrode 202b. FIG. 6 shows an example of the measurement result of the peak voltage value (Vs) of the signal line immediately before the protected device by the static electricity test. FIG. 6 shows a sample No. of the antistatic component of this embodiment. 2 is an example of a measurement result of Vs1 of 1.

  Further, in the electrostatic test, in order to evaluate the resistance of the varistor to the electrostatic pulse, an 8 kV electrostatic pulse was applied five times to evaluate the rate of change (ΔV1 mA) of the varistor voltage (V1 mA) before and after the test. The evaluation results are also shown in (Table 2). In Table 2, ΔV1mA1 is the evaluation result of the first varistor 204a, and ΔV1mA2 is the evaluation result of the second varistor 204b.

  As is clear from the evaluation results shown in Table 2, the conventional laminated varistor having a capacitance (C) of Comparative Example 1 of about 0.7 pF has a differential impedance variation (ΔZ) of −11Ω. Although the transmission characteristics when used in a dynamic transmission circuit are good, the peak voltage value (Vs) is very large at 620 V, and the effect of suppressing absorption against electrostatic pulses is insufficient, and the rate of change of the varistor voltage (V1 mA) (ΔV1 mA) However, the resistance to electrostatic pulses was as large as -21% and was insufficient. Further, the conventional laminated varistor having a capacitance (C) of Comparative Example 2 of about 1.7 pF has a peak voltage value (Vs) of 345 V and a rate of change (ΔV1 mA) of the varistor voltage (V1 mA) of −5%. Although the absorption suppressing effect against electrostatic pulses and the resistance to electrostatic pulses are good, the differential impedance fluctuation (ΔZ) is as extremely large as −32Ω, and the transmission characteristics when used in a differential transmission circuit are insufficient.

On the other hand, the sample No. 1 to 6 have good transmission characteristics when used in a differential transmission circuit with a differential impedance fluctuation (ΔZ) of −21Ω and a peak voltage value (Vs) of about 350 V or less. Thus, the rate of change (ΔV1 mA) of the varistor voltage (V1 mA) was −6% or less, and the absorption suppression effect against electrostatic pulses and the resistance against electrostatic pulses were sufficient. From these evaluation results, the ESD protection component of the present embodiment has both good transmission characteristics and absorption suppression effect against electrostatic pulses, and is particularly suitable for ESD protection in high-speed differential transmission circuits. It could be confirmed. Particularly, the connection distance between the resistor and the varistor in terms of electrical length the 50psec below, sample No. of the embodiment the resistance value of the resistor was set to more than 15Ω The 2, 3, 4 and 5 anti-static parts all have a very small differential impedance fluctuation (ΔZ) of −15Ω or less, and the transmission characteristics when used in a differential transmission circuit are particularly good. Differential impedance at TDR, which is a strict transmission standard required for HDMI (High Definition Multimedia Interface, transmission rate of 1.5 Gbps at 1080P) used as a high-speed interface for digital TVs, etc., satisfies a standard within 100Ω ± 15Ω It was a thing.

  As described above, the anti-static component of the present invention is provided with ceramic firing provided with the first and second input external electrodes, the first and second output external electrodes, and the ground external electrode. A first resistor that is electrically connected to the first input external electrode and the first output external electrode is formed on the ceramic sintered body to form the first output; Forming a first varistor electrically connected to the external electrode for ground and the external electrode for ground, and a second electrically connected to the second external electrode for input and the second external electrode for output. And a second varistor which is electrically connected to the second output external electrode and the ground external electrode, and has a resistance on the input external electrode side of the transmission line. By connecting the body to a varistor, Since the fluctuation (ΔZ) of the impedance can be reduced and the transmission characteristics are improved, both the transmission characteristics in the high-speed differential transmission circuit and the absorption suppression effect against electrostatic pulses are both good, especially as a countermeasure against static electricity in the high-speed differential transmission circuit. Suitable anti-static parts can be realized.

  The antistatic component of the present invention can be reduced in size because a resistor and a varistor are laminated and integrated inside a ceramic sintered body made of a varistor material. Since the ceramic sintered body is composed of a single varistor material, there is no problem of deterioration of characteristics due to the influence of the composition of the dissimilar materials generated when the laminated sintered body is composed of dissimilar ceramic materials. As described above, it is possible to easily obtain the desired characteristics. In addition, on the joint surfaces of different ceramic materials, mechanical strength and reliability problems are likely to occur due to differences in thermal expansion coefficient and shrinkage behavior during the firing process. There is no problem with joining ceramic materials.

  In the anti-static component in the one embodiment, the ceramic sintered body includes the first and second input external electrodes, the first and second output external electrodes, and the ground external electrode. In this example, two signal lines, that is, two resistors, two varistors, and a ground are used for a pair of differential transmission circuits. There may be multiple pairs of applications that use the circuit. When such a plurality of pairs of differential transmission circuits are applied, the first and second input external electrodes, the first and second output external electrodes, and the ground are applied to the ceramic sintered body. A plurality of pairs of external electrodes may be provided, and a plurality of pairs of signal lines may be integrated. In this way, the antistatic component having a configuration in which a plurality of pairs of signal lines are integrated can improve the signal shift for each differential transmission pair caused by the difference in the characteristics of individual elements and their mounting states. Therefore, it is possible to realize an anti-static component that can be miniaturized and improve the quality of the entire transmission characteristics.

In the method of manufacturing an antistatic component in the above embodiment, ceramic powder containing zinc oxide as a main component and Bi ₂ O ₃ as an additive is used as a varistor material, but Pr oxide is added. A zinc oxide varistor material or a ceramic material having varistor characteristics such as SrTiO ₃ or BaTiO ₃ may be used.

  The anti-static component according to the present invention is a ceramic sintered body in which a resistor and a varistor are laminated and integrated, so that it can be miniaturized and highly reliable, and can reduce fluctuations in differential impedance and transmission characteristics. Therefore, both the transmission characteristics in the high-speed differential transmission circuit and the absorption suppression effect against electrostatic pulses are good, and it is particularly useful as a static electricity countermeasure component suitable for static electricity countermeasures in the high-speed differential transmission circuit.

The schematic exploded perspective view of the ceramic sintered compact in one embodiment of this invention 1 is an external perspective view of an anti-static component according to an embodiment of the present invention. Equivalent circuit diagram of the static electricity countermeasure parts The graph which shows the example of the measurement result of the fluctuation | variation ((DELTA) Z) of the differential impedance in one embodiment of this invention Circuit diagram of electrostatic test in one embodiment of the present invention The graph which shows the example of the measurement result of the peak voltage value (Vs) in the electrostatic test in one embodiment of this invention

Explanation of symbols

101a, 201a First input external electrode 101b, 201b Second input external electrode 102a, 202a First output external electrode 102b, 202b Second output external electrode 103, 203 Ground external electrode 104a, 204a First varistor 104b, 204b Second varistor 105a, 205a First resistor 105b, 205b Second resistor 200 Ceramic sintered body 210 Ceramic layer 214a, 214b, 224 Internal electrode 215a, 215b Wiring conductor 225a, 225b Via conductor 401 Power supply 402, 406 Resistor 403, 405 Switch 404 Capacitance box 407 Ground line 408 Signal line 409 Evaluation sample 410 Protected device

Claims (2)

An anti-static component for use in a differential transmission circuit, comprising ceramic firing provided with first and second input external electrodes, first and second output external electrodes, and a ground external electrode. A first resistor that is electrically connected to the first input external electrode and the first output external electrode is formed on the ceramic sintered body to form the first output; Forming a first varistor electrically connected to the external electrode for ground and the external electrode for ground, and a second electrically connected to the second external electrode for input and the second external electrode for output. And forming a second varistor electrically connected to the second output external electrode and the ground external electrode, and the first resistor and the first varistor. Connection distance and the second resistor and the second varistor The connection distance, to a 50psec less in terms of electrical length, the resistance value of said first resistor and said second resistor, ESD protector has a higher 15 [Omega]. 2. The antistatic component according to claim 1, wherein a plurality of pairs of first and second input external electrodes, first and second output external electrodes, and ground external electrodes are provided.

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