JP5212059B2 - Voltage nonlinear resistor composition and multilayer varistor - Google Patents

Description

  The present invention relates to a voltage nonlinear resistor composition used for a varistor suitable for protecting an electronic device from static electricity, and a laminated varistor using the same.

  A semiconductor device such as an IC used for an electronic apparatus may be broken or deteriorated in characteristics due to static electricity (ESD). In particular, recent semiconductor devices are becoming vulnerable to ESD as their speed increases, and destruction of semiconductor devices due to ESD causes serious failures such as malfunctions and failures in electronic devices. For this reason, the importance of ESD countermeasures in various electronic devices has been increasing in recent years, and ZnO-based varistors of voltage nonlinear resistors are widely used as countermeasure parts.

  As a varistor used for ESD countermeasures, it is naturally desirable to have excellent ESD absorption characteristics. In addition, the varistor itself must not be destroyed by ESD, and the ESD resistance needs to be excellent. More recently, due to a strong demand for downsizing of electronic devices, it is desired to have a small shape and a low capacitance of several pF or less that can cope with high frequency circuit signals and does not deteriorate transmission characteristics. Yes.

For example, Patent Document 1 of a rare earth system such as Pr and Patent Document 2 of a Bi system are known as prior art document information regarding such a multilayer varistor mainly composed of ZnO for ESD countermeasures.
JP 2004-146675 A JP 2007-5500 A

However, conventional laminated varistors have not been sufficient for the above-described characteristics requirements. ZnO-based varistors are generally roughly classified into two types, Pr-based and Bi-based, depending on varistor characteristic expression additives. Among them, the Pr-based multilayer varistor is suitable for lowering the varistor voltage. For example, it has a low varistor voltage V _{1 mA of} about 8 to 39 V (voltage value at a current value of 1 mA), and has excellent ESD absorption characteristics and ESD resistance. Things have been obtained. However, since the dielectric constant is generally about 700, in a multilayer varistor with a low varistor voltage V _{1 mA} of about 8 to 39 V, the electrode interval is narrowed, so that the increase in capacitance becomes more obvious and it is difficult to reduce the capacitance. Therefore, there is a problem that it is unsuitable for high-frequency signal lines.

  On the other hand, Bi-based multilayer varistors have a dielectric constant as low as about 70 while having excellent voltage nonlinearity. Accordingly, a laminated varistor having a very small capacitance value of 0.5 to 1 pF has been obtained. However, since the reduction in the electrode area accompanying the reduction in capacitance leads to an increase in current density, the varistor voltage is set to 100 V or less. If the pressure is reduced to a low level, deterioration of characteristics due to ESD tends to occur. For this reason, if the practical ESD tolerance is satisfied, only a high varistor voltage of about 100 V can be realized, it is difficult to reduce the varistor voltage, the ESD absorption characteristics are insufficient, and the ESD countermeasure of the device is likely to be insufficient. There is a problem.

  Against such a background, ESD countermeasures for high-frequency transmission applications require a multilayer varistor that realizes a small capacitance that does not adversely affect transmission characteristics, has a large ESD suppression effect, and is excellent in its resistance. .

  SUMMARY OF THE INVENTION The present invention solves the above problems, and realizes a multilayer varistor that realizes low varistor voltage and low capacitance, is excellent in ESD resistance, and is suitable for use in a high-frequency transmission circuit, and the multilayer varistor. An object of the present invention is to provide a voltage non-linear resistor composition suitable for the above.

In order to achieve the above object, the voltage non-linear resistor composition of the present invention has, in particular, ZnO as a main component and a general formula (1-x) ZnO + x [Sr _{1- y My} ] _1-a Co _{1+ When} represented by aO ₃ , M is at least one of Ca and Ba, x, y and a represent molar ratios, 0.0005 ≦ x ≦ 0.10, 0 ≦ y ≦ 0.8 and − It is set as the structure which is 0.1 <= a <= 0.2.

  The multilayer varistor of the present invention has a ceramic sintered body having a plurality of internal electrodes therein, and an external electrode electrically connected to the internal electrodes and formed on the surface of the ceramic sintered body, The ceramic sintered body is formed using the voltage non-linear resistor composition described above.

  According to the voltage nonlinear resistor composition of the present invention, with the above-described configuration, a very low varistor voltage, excellent nonlinearity, and an extremely low dielectric constant can be realized as its electrical characteristics. Moreover, it will have the fine structure ZnO crystal particle. And by these characteristics, as a voltage non-linear resistance body, it can have the electrical property which was excellent, and it was highly reliable with the outstanding ESD tolerance.

  In addition, according to the multilayer varistor of the present invention, the above-described configuration makes the varistor voltage excellent in ESD resistance while obtaining a low varistor voltage and a small capacitance, and is suitable for high frequency transmission circuit applications. A varistor can be realized.

(Embodiment 1)
Hereinafter, the voltage nonlinear resistor composition of the present invention will be described in detail based on an example.

First, as a starting material, ZnO as a main component, SrCO ₃ , Co ₂ O ₃ , CaCO ₃ , BaCO ₃ as subcomponents, and Al ₂ O _{3 as} a _second subcomponent, a chemically high-purity powder Prepared. Subsequently, when the composition after sintering is represented by the general formula (1-x) ZnO + x [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ , the values of x, y, and a are each atom. The starting materials are weighed so that the composition ratios shown in Sample Nos. 1 to 52 in (Table 1) are converted, and the balance is ZnO. The component, Al ₂ O _3, was added and weighed so that the composition ratios shown in Sample Nos. 47 to 52 in (Table 1) were obtained.

  These starting material powders were put in a polyethylene ball mill, stabilized zirconia boulders and pure water were added and mixed for about 20 hours, and then dehydrated and dried. This dried powder was put into a high-purity alumina crucible and calcined at about 750 ° C. for 2 hours. Next, this calcined powder was put in the same ball mill as that used for mixing, cobblestone made of stabilized zirconia and pure water were added and pulverized for about 20 hours, and then dehydrated and dried.

Next, an organic binder is added to the dried raw material powder, and the mixture is mixed homogeneously. After being sized through a 32 mesh sieve, it is molded using a mold and a hydraulic press at a molding pressure of ² ton / cm ² and has a diameter of 13 mm and thickness. A molded body of 1.3 mm was obtained. Next, a Pd-based electrode paste to be electrodes is formed on the upper and lower surfaces of the molded body by printing and drying, and then the molded body is placed in a heat-resistant zirconia sheath at a firing temperature of 1000 to 1100 ° C. in the atmosphere. Firing was performed for 2 hours to obtain a voltage nonlinear resistor having the composition shown in sample numbers 1 to 52 of (Table 1).

Next, the varistor characteristics and the dielectric constant were evaluated for the electrical characteristics of each of the obtained voltage nonlinear resistors of sample numbers 1 to 52. The varistor characteristics are evaluated by measuring the voltage value when a current is applied to the sample in the range of 1 μA to _{1 mA, and} the varistor voltage V _{1 mA} / mm (V) per unit thickness is evaluated from the voltage-current characteristics. Non-linearity α was determined. The varistor voltage V _{1 mA} was defined as a voltage value when the current value was 1 mA, and the varistor voltage V _{1 mA} / mm (V) per unit thickness was obtained from the element thickness of the sample. Further, the non-linearity α was evaluated by a ratio V _{1 mA} / V _{10 μA} of a voltage value V _{1 mA} when the current value was 1 _mA and a voltage value V _{10 μA} when the current value was 10 μA. Accordingly, the non-linearity α is a voltage non-linear resistance element that is ideal and has excellent non-linearity as the non-linearity is closer to 1.

The dielectric constant ε _r was obtained from a capacitance measured under a measurement frequency of 1 MHz, a measurement voltage of 1 Vrms and no DC bias, and from the capacitance and the element thickness and diameter of the sample. Also, an average crystal grain size D _g of ZnO grains by intercept method from the observation image using an electron microscope to evaluate the microstructure of samples of crystal.

  The evaluation results for the voltage nonlinear resistors of sample numbers 1 to 52 are shown in (Table 1) together with their compositions. In Table 1, those marked with * are comparative examples outside the scope of the present invention.

  Hereinafter, the reason for limiting the composition range of the voltage nonlinear resistor composition of the present invention will be described in detail with reference to (Table 1).

As in Sample No. 1, if [Sr _1-y M _{y] 1-a Co 1 + a O} 3 molar ratio x is less than 0.0002mol the varistor characteristics is not expressed. The expression of varistor characteristics can be seen from the sample number 2 where x is 0.0002 mol, but with this addition amount, there is a large difference in characteristics between particles and grain boundaries. α is bad and is not a practical characteristic. In order for the characteristics to be uniform between the particles and the practical non-linearity α to be 2.0 or less, it is necessary that x is 0.0005 mol or more as in sample numbers 3 to 15. On the other hand, when x is more than 0.10 mol as in sample numbers 16 to 17, the phase that excessively precipitated as the secondary phase at the ZnO particle interface is increased in varistor voltage (V _{1 mA} / mm> 500 V). , Leading to deterioration of nonlinearity (α> 2.0) and increase of dielectric constant (ε _r > 50). These characteristic changes lead to a decrease in ESD absorption characteristics and a deterioration in signal line transmission quality, which is not practical and not desirable for the purpose of the present invention.

Further, as in sample number 5, sample number 21 and sample number 31, when the molar ratio a of [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ is more negative than −0.1 mol, When the molar ratio a is larger than 0.2 mol as in Sample No. 10, Sample No. 26 and Sample No. 36, the varistor voltage is increased (V _{1 mA} / mm> 500 V), and the average crystal particle diameter D _g is This is unpreferable and not practical for the purpose of the present invention.

Therefore, a composition suitable for a voltage nonlinear resistor for high-frequency transmission has as its characteristics a very low varistor voltage with V _{1 mA} / mm of 500 V or less, excellent nonlinearity with α of 2.0 or less, and A composition that provides an extremely low dielectric constant of ε _r of 50 or less, that is, _expressed by the general formula (1-x) ZnO + x [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ containing ZnO as a main component. In this case, a composition range in which X is 0.0005 mol or more and 0.10 mol or less and a is −0.1 mol or more and 0.2 mol or less is preferable.

[Sr _{1- y My} ], such as sample numbers 8-9 compared with sample number 7, sample numbers 24-25 compared with sample number 23, and sample numbers 34-35 compared with sample number 33 The molar ratio a in _1-a Co _{1 + a} O _{3 is} in the range of 0 <a ≦ 0.2, and the composition is such that CO at the B site is excessive compared to [Sr _{1- y My} ] at the A site. In this case, the effect of further reducing the varistor voltage while maintaining a low dielectric constant and excellent non-linearity can be obtained. This lowering of the varistor voltage leads to further improvement of the ESD absorption effect.

[Sr _1-y M] Sample numbers 19, 20, 23 and 27 compared with sample number 18, sample numbers 30, 33, 37 and 38 compared with sample number 29, and sample numbers 40 to 45 _y ] _1-a Co _{1 + a} O ₃ having a composition in which part of Sr at the A site is substituted with at least one of Ca and Ba maintains a low dielectric constant and excellent non-linearity. An effect of further reducing the varistor voltage can be obtained. This lowering of the varistor voltage leads to further improvement of the ESD absorption effect.

However, when the molar ratio y of substitution is larger than 0.8 as in Sample No. 28 and Sample No. 39, an increase in dielectric constant is caused by both Ba and Ca element species. Therefore, in order to obtain a very low dielectric constant with ε _r of 50 or less, the molar ratio y of substitution is preferably a composition range of 0.8 or less.

In addition, when the molar ratio y of substitution at the A site is 1.0 and all of the Sr at the A site is completely substituted, particularly when Ba is completely substituted as in the sample No. 39, abnormalities in crystal grains are observed. There is a tendency to cause growth, and the average crystal particle diameter _Dg also increases. Such a microstructure that has become non-uniform due to abnormal growth of ZnO particles is reflected in the difference in current density at the particles and their interfaces. For this reason, not only non-linearity, but particularly at the coarse particle interface, local concentration of current density due to ESD is likely to occur, which becomes a starting point for destruction. For this reason, the microstructure is also a secondary factor that adversely affects non-linearity and ESD resistance. On the other hand, the composition having a substitution molar ratio y of 0.8 or less has no abnormal growth of ZnO particles, the average crystal particle diameter _Dg is small and uniform, and can improve non-linearity and ESD resistance. Thus, the effect of increasing the reliability can be obtained.

For the above reasons, the composition of the voltage nonlinear resistor for high-frequency transmission is characterized by its very low varistor voltage with V _{1 mA} / mm of 500 V or less and excellent nonlinearity with α of 2.0 or less. , And a composition with which an extremely low dielectric constant of ε _r of 50 or less is obtained, that is, with ZnO as a main component and a general formula (1-x) ZnO + x [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ When expressed, M is at least one of Ca and Ba, x is 0.0005 mol or more and 0.10 mol or less, M molar ratio y is 0.8 or less, and a is −0.1 mol or more and 0.00. A composition that is 2 mol or less is suitable.

Furthermore, as in Sample Nos. 47 to 52 compared with Sample No. 46, a composition in which a small amount of Al ₂ O ₃ is added as the second subcomponent is effective for making finer and more uniform crystal grains. Further, the non-linearity and the ESD resistance can be improved, and the effect of increasing the reliability can be obtained. In addition, since the mechanical strength is naturally improved by making the ceramic structure fine and uniform, there is also an effect of increasing the reliability against thermal shock and drop impact of the device. However, as in sample numbers 51 to 52, when the addition amount is large, the dielectric constant increases. Therefore, in order to obtain a very low dielectric constant with ε _r of 50 or less, the amount of Al ₂ O ₃ added to 1 mol of the main composition is preferably within a composition range of 0.003 mol or less.

The voltage nonlinear resistor composition of the present invention was analyzed by composition analysis and X-ray diffraction. As a result, in addition to the crystal phase of ZnO, the grain boundary between the ZnO particles had a perovskite structure [Sr it was confirmed that the _1-y M _{y] 1-a Co 1 + a O} 3 solid solution phase. From this result, the perovskite-type in the ZnO grain boundaries [Sr _1-y M _{y] 1-a Co 1 + a O} 3 compound was confirmed to have effects as varistor characteristics expressed substance. Therefore, it is possible to be a perovskite [Sr _1-y M _{y] 1-a Co 1 + a O} 3 compound previously synthesized was added to ZnO obtain the same characteristics. As is clear from the above, the above-mentioned excellent characteristics can be obtained by including perovskite type [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ compound in the composition range of the present invention in ZnO. It is.

As described above, the voltage nonlinear resistor composition of the present invention contains ZnO as a main component and is represented by the general formula (1-x) ZnO + x [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ When M is expressed, M is at least one of Ca and Ba, and x is 0.0005 mol or more and 0.10 mol or less, y is 0.8 mol or less, and a is -0.1 mol or more and 0.2 mol or less. As a result, its electrical characteristics include a very low varistor voltage with V _{1 mA} / mm of 500 V or less, excellent non-linearity with α of 2.0 or less, and extremely low dielectric constant with ε _r of 50 or less. it can. Moreover, it has a fine structure with an average crystal particle diameter of 2.0 μm or less. And thereby, the non-linearity as a voltage non-linear resistance body and the improvement of ESD tolerance can be aimed at, and reliability can be improved more.

As described above, the voltage nonlinear resistor composition of the present invention has ZnO as a main component and M is at least one of Ca and Ba [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ are those containing, [Sr _1-y M _{y] 1-a Co 1 + a O} 3 is to form an acceptor level in ZnO particle interface of the N-type semiconductor, the barrier properties of the polycrystalline body tissue (Varistor characteristics) Origin of expression. In this respect, it plays the same role as the conventional Bi oxide and Pr oxide, but one grain obtained from the varistor voltage V _{1 mA} / mm and the average crystal particle diameter D _g of the sample in one example of the present invention. The barrier height (V _gh ) per boundary is 0.4 to 0.6 eV, and is generally 0.6 to 1.0 eV (Pr system) and 0.8 to 1.4 eV (Bi system) in the conventional composition. In comparison with), lower values of material properties are obtained. This means that, in designing a varistor product as an anti-static component, the varistor voltage is the product of the number of grain boundaries N and V _gh , which is essentially advantageous for lowering the voltage. According to the researches of the inventors, Bi oxides in Bi-based varistors have the property of changing various states (liquid phase and phase transition) from about 600 ° C. or higher, which is the heat generated by ESD. Energy leads to characteristic changes and thermal destruction, causing element characteristic deterioration. In contrast, [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ in which M of the present invention is at least one of Ca and Ba has a melting point of 1500 ° C. or more and is excellent in thermal stability. , M is by using at least one of Ca and Ba and [Sr _1-y M _{y] 1-a Co 1 + a O} 3 as an expression material of the non-linear resistance characteristic, the voltage very excellent ESD immunity A non-linear resistor can be obtained.

Furthermore, constituent elements of the M is at least one of Ca and Ba [Sr _1-y M _{y] 1-a Co 1 + a O} 3 , since than Pr is light element, the dielectric constant of the crystal is In general, since the depletion layer region at the grain boundary portion is the same, the dielectric constant is essentially low because it is small. Thus, since M is a grain boundary by using at least one of Ca and Ba and [Sr _1-y M _{y] 1-a Co 1 + a O} 3 to the characteristic expression material, which is low dielectric constant, It is also possible to reduce the capacitance of the voltage nonlinear resistor element.

(Embodiment 2)
Hereinafter, the multilayer varistor of the present invention will be described in detail based on the characteristics of an example in the case where a multilayer varistor is manufactured using the voltage nonlinear resistor composition described in the first embodiment.

First, as voltage non-linear resistor composition for producing a multilayer varistor, sample numbers 2, 7, 8, 11, 15, 16, 19, 23, 24 from (Table 1) of the first embodiment are used. , 33, 34, 39, 43, 46, and 49 were selected. As in the first embodiment, as starting materials, ZnO as a main component, SrCO ₃ , Co ₂ O ₃ , CaCO ₃ , BaCO ₃ as subcomponents, and Al ₂ O _{3 as a second} subcomponent. Were prepared, and the starting materials were weighed so that the composition ratio corresponded to the sample number. Subsequently, mixing, drying, calcination, pulverization, and drying were performed by the same method as in Embodiment 1 to prepare and prepare 15 types of raw material powders having the composition ratios of the respective sample numbers.

  Next, 15 types of laminated varistors in Embodiment 2 were produced using each of the 15 types of raw material powders. The laminated varistor was produced by the following method.

  First, an organic binder, a solvent, and a plasticizer were added to the raw material powder, mixed, and molded by a doctor blade method to prepare and prepare a green sheet. Then, a conductor layer serving as an internal electrode was formed on the green sheet by screen printing using an AgPd alloy (Ag70 / Pd30) paste. Next, the green sheet in which the conductor layer used as an internal electrode was laminated | stacked and pressurized, and the laminated body block was obtained. Next, the laminated body block was cut and separated into a desired size to obtain individual raw chips. The raw chip was heated to about 500 ° C. in the atmosphere to remove the binder, and then heated to 1000 to 1100 ° C. in the atmosphere and fired to obtain a sintered body element.

Next, the sintered body element is barrel-polished to expose internal electrodes on both end faces of the sintered body element, and then an Ag paste is applied and dried and baked at 750 to 850 ° C., and then Ni-Sn plating is formed. Thus, 15 types of laminated varistors in Embodiment 2 were produced. As for the external dimensions of the laminated varistors in the produced second embodiment, the longitudinal direction was 1.0 mm, the width direction was 0.5 mm, and the thickness direction was 0.5 mm. In any case, the varistor layer had a thickness of about 70 μm, two layers, and an area per layer of about 0.06 mm ² .

The electrical characteristics of these 15 types of laminated varistors according to the second embodiment were evaluated. As for the electrical characteristics, the varistor voltage V _{1 mA} , the voltage ratio V _{1 mA} / V _{10 μA} , and the capacitance were evaluated as an index of the non-linearity α, as in the first embodiment. And in addition to these, ESD tolerance was evaluated. The ESD resistance was evaluated from a change in characteristics before and after applying an ESD voltage of 8 kV (charging capacity: 150 pF, discharging resistance: 330Ω) based on IEC61000-1-4 to the device using an electrostatic discharge simulator. Moreover, the change rate ΔV _{1 mA} from the initial value of the varistor voltage after the ESD voltage is applied is shown as an evaluation result of the ESD resistance. The evaluation results of the electrical characteristics of the laminated varistor in Embodiment 2 are shown in Table 2 together with the sample number of the composition used. In Table 2, those marked with * are comparative examples outside the scope of the present invention.

As is clear from the evaluation results of (Table 2), sample number 101 (composition of sample number 2) of the comparative example has poor nonlinearity and large capacitance, and sample number 106 (sample number) of the comparative example. 16 composition) has poor nonlinearity, the varistor voltage is high, and the sample number 112 (composition of sample number 39) of the comparative example has a large capacitance of 3 pF or more. It does not satisfy the electrical characteristics intended for varistors with low varistor voltage and low capacitance. In addition, the ESD resistance is not a practical characteristic because the change rate ΔV _{1 mA} is as large as −50% or more.

On the other hand, the laminated varistors of the present invention of sample numbers 102 to 105, sample numbers 107 to 111, and sample numbers 113 to 115 are all varistor voltage V _{1 mA} of 28 to 45 V, nonlinearity α is 1.3 or less, Capacitance is 0.5 to 1.3 pF, has a balanced electrical characteristic compared to the comparative example, and has excellent electrical characteristics as a varistor with a low varistor voltage and a low capacitance. It was. Also, the ESD resistance was excellent in ESD resistance with a small change rate ΔV _{1 mA} of about −21% or less. These electrical characteristics indicate a low varistor voltage and a low capacitance value in a characteristic region that cannot be obtained by the conventional Pr-based and Bi-based compositions, and also have extremely excellent ESD resistance. This excellent ESD resistance is obtained because the varistor layer is a polycrystalline body having a uniform microstructure in addition to a grain boundary structure excellent in thermal stability.

  As described above, the multilayer varistor of the present invention produced using the voltage nonlinear resistor composition of the present invention has a low varistor voltage, a low capacitance, a very excellent ESD resistance, A varistor suitable for ESD countermeasures in electronic equipment can be realized.

  In addition, the voltage non-linear resistor composition of the present invention can produce a dense sintered body at a firing temperature of 1000 to 1100 ° C., so that an inexpensive AgPd alloy paste of an internal electrode material can be used. Can also be cheap.

In general, if the change rate ΔV _{1 mA} of the ESD resistance is within 30%, it can be used without any practical problem. Therefore, in the multilayer varistor using the voltage nonlinear resistor composition of the present invention, It is also possible to further reduce the varistor voltage or lower the capacitance within the allowable range of the change rate of the ESD resistance. The varistor voltage can be lowered by reducing the thickness of the varistor layer between the electrodes. To reduce the capacitance, the varistor layer can be increased by increasing the thickness of the varistor layer or arbitrarily adjusted by the electrode area. It is. It is also possible to adjust electrical characteristics such as varistor voltage and capacitance according to the required level and application of the ESD resistance voltage.

  The voltage non-linear resistor composition according to the present invention has low varistor voltage, excellent non-linearity, and extremely low dielectric constant as its electrical characteristics, and also has small and uniform crystal grains and excellent ESD. Tolerance is obtained. The multilayer varistor according to the present invention using this voltage non-linear resistor composition has a low varistor voltage, a low capacitance, a very excellent ESD resistance, and is suitable for ESD countermeasures in various electronic devices. It is particularly useful as a varistor.

Claims (7)

When ZnO is the main component and represented by the general formula (1-x) ZnO + x [Sr _{1- y My} ] _1-a Co _{1 + a} O ₃ , M is at least one of Ca and Ba, and x, y and a represent a molar ratio, and the voltage nonlinear resistor composition which is 0.0005 <= x <= 0.10, 0 <= y <= 0.8, and -0.1 <= a <= 0.2. The voltage nonlinear resistor composition according to claim 1, wherein a is in a range of 0 <a ≦ 0.2. 2. The voltage nonlinear resistor composition according to claim 1, wherein a grain boundary of the main component ZnO particles has a solid solution phase having a perovskite structure. A voltage nonlinear resistor composition containing 0.003 mol or less of Al in terms of Al ₂ O ₃ with respect to 1 mol of the composition according to claim 1. The voltage nonlinear resistor composition according to claim 1, wherein the average crystal particle diameter is 2 μm or less. The voltage nonlinear resistor composition according to claim 1, which does not contain Bi and Pr. A ceramic sintered body having a plurality of internal electrodes therein, and an external electrode electrically connected to the internal electrode and formed on a surface of the ceramic sintered body, the ceramic sintered body comprising: A multilayer varistor formed using the voltage nonlinear resistor composition according to any one of 1 to 6.