Ceramic device and method for manufacturing the same

Abstract

To provide a ceramic device including a ceramic substrate.SOLUTION: A ceramic substrate includes a ceramic material as its main component; the general formula of the ceramic material is AxByC1-x-vTi1-y+wO3*(Mn2 P2O7)z*Du (A is selected from the group consisting of Nd, Pr, Ce and La, B is selected from the group consisting of Nb, Ta and V, C is selected from the group consisting of Ca, Sr and Ba, D is an additive that contains a compound containing at least one selected from the group consisting of Al, Ni and Fe, x is a ratio of A, y is a ratio of B, v is a ratio of vacancies in A, w is a ratio of excess Ti, z is a ratio of Mn2P2O7, u is a ratio of D, 0.0≤x<0.1, 0.0≤y<0.1, 0≤v<1.5*x, 0≤w<0.05, 0.01≤z<0.1, 0≤u<0.05).SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a ceramic device including a ceramic substrate having a ceramic material. The present invention also relates to a method for manufacturing a ceramic device.

[0002] Ceramic devices are widely used in electronic components. As the miniaturization of electronic components and the demand for effective power increase, it is necessary to provide smaller ceramic devices. However, when the size of a conventional ceramic device using a ceramic material becomes smaller, it particularly has an adverse effect on the electrical characteristics of the ceramic device. For this reason, by miniaturizing a capacitor using a conventional ceramic material, for example, the sensitivity to electrostatic discharge (ESD) inside the capacitor may increase, and there is a possibility that the capacitor may become unusable due to ESD.

[0003] International Application German Translation No. 11 2012 000 669 describes a first example of a ceramic element according to the prior art so far.

[0004] International Application German Translation No. 11 2012 000 669 describes a laminated semiconductor ceramic capacitor having a varistor function and a method for manufacturing the same, and in particular, discloses an SrTiO3-based grain boundary insulating semiconductor ceramic used for the varistor function. Further, an embodiment of adding a dopant to the corresponding semiconductor ceramic is disclosed, and the dopant is mainly selected from lanthanum, neodymium, niobium, and tantalum.

[0005] French Patent Publication No. 2 799 301 describes a second example of a ceramic element according to the prior art so far.

[0006] French Patent Publication No. 2,799,301 describes a non-linear resistor that can be used to protect the power grid from overvoltage and a method for manufacturing the same. Further, it is disclosed that this non-linear resistor has zinc oxide as a main component, a high-resistance layer is provided on the side surface of the non-linear resistor, and manganese pyrophosphate may be added to this non-linear resistor.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0008] In view of the above circumstances, an object of the present invention is to provide a ceramic device including a ceramic substrate mainly composed of an improved ceramic material. Another object of the present invention is to provide a method for manufacturing a ceramic device.

Means for Solving the Problems

[0009] The solution means of the present invention for achieving the above object is the ceramic device according to claim 1. For other embodiments of the ceramic device and the method for manufacturing the ceramic device, refer to other claims.

[0010] A ceramic device having a ceramic substrate is provided. The ceramic substrate includes a ceramic material as a main component, and the ceramic material has a general formula A x B y C 1-x-v Ti 1-y+w O3 * (Mn2P2O7) z * D uIt is represented by. In the general formula, A is the first doping selected from the group of the first metals consisting of neodymium, praseodymium, cerium and lanthanum. Also, B is the second doping selected from the group of the second metals consisting of niobium, tantalum and vanadium. Also, C is the main component of the base ceramic material, and the main component is selected from the group of the third metals consisting of calcium, strontium and barium. Further, D is an additive containing at least one first compound, and the compound contains a fourth metal selected from the group of the fourth metals consisting of aluminum, nickel and iron. Also, x is the ratio of the amount of A, y is the ratio of the amount of B, v is the ratio of the amount of vacancies of A, w is the ratio of the amount of excess titanium, z is the ratio of the amount of Mn2P2O7, and u is the ratio of the amount of D. With respect to the ratio of the amounts, 0.0 ≦ x < 0.1, 0.0 ≦ y < 0.1, 0 ≦ v < 1.5 * x, 0 ≦ w < 0.05, 0.01 ≦ z < 0.1 The relationship of 0 ≦ u < 0.05 is applicable.

[0011] Hereafter, the base ceramic material refers to a base compound represented by the general formula CTiO3, where C is the main component of the base ceramic material, and the main component is selected from the group of the third metals.

[0012] Also, hereafter, the first doping refers to the first metal that occupies the atomic position of the third metal in the lattice of the base ceramic material.

[0013] Also, hereafter, the second doping refers to the second metal that occupies the atomic position of titanium in the lattice of the base ceramic material.

[0014] In one embodiment of the ceramic material, the ceramic material includes a base ceramic material containing the first doping and the second doping, at least one additive, and manganese pyrophosphate represented by the composition formula Mn2P2O7.

[0015] The values of the ratios of the first doping, the second doping, and the amount of the additive may all be zero. In other words, in addition to the base ceramic material, the ceramic material may contain only one of the first doping, the second doping, and the additive. Further, the ceramic material may contain only the first doping and the additive, or only the second doping and the additive, as complementary to the base ceramic material. Furthermore, the ceramic material may contain only the base ceramic material including the first doping and the second doping. In this case, the ceramic material does not contain any additive. In all of the above-described embodiments, the ratio of manganese pyrophosphate contained in the ceramic material is greater than zero. In other words, the ceramic material always contains manganese pyrophosphate.

[0016] Also, the first doping may contain at least two first metals, the second doping may contain at least two second metals, and the main component of the base ceramic material may contain at least two third metals.

[0017] Also, the additive may contain at least one first compound and a second compound, and these compounds each contain one fourth metal. Among them, the fourth metal contained in the first compound is different from the fourth metal contained in the second compound. That is, the first compound contains a fourth metal different from the second compound. As the first compound and the second compound, a metal oxide containing at least one fourth metal may be used.

[0018] The ceramic material preferably has any of the combinations of components shown in Table 1 below.

[0019]

Table 1

[0020] In Table 1, B1 represents a second metal, B2 represents another second metal, and these metals are included in the second doping B, where the coefficients y1 and y2 are the proportions of the amounts respectively occupied by the second metals B1 and B2 in the second doping B. The sum of the coefficients y1 and y2 is the proportion y of the amount of the second doping in the ceramic material.

[0021] Also, C1 represents a third metal, C2 represents another third metal, and C3 represents yet another third metal, and these metals are included in the main component C of the substrate material. The values of C1, C2, and C3 represent the proportions of the corresponding third metals in the main component C, where the sum of the values of C1, C2, and C3 is 1.

[0022] Also, D1 represents a fourth metal, D2 represents another fourth metal, and these metals are included in the additive D. The sum of the coefficients u1 and u2 is the proportion u of the amount of the additive contained in the ceramic material.

[0023] Note that the proportions of the amounts of the components of the ceramic material may vary within a range of up to 10% corresponding to Examples 1 to 7 described in Table 1. Therefore, the proportion of the amount of the first doping x in Example 1 is not limited to a value of 0.02, for example. Exactly, x may have all values within the range of 0.018 to 0.022. Similarly, all other values of the corresponding proportions of the amounts described in Table 1 may also vary within a range of up to 10%. The advantageous proportions vary within a range of up to 5% of the values described in the table. This means that in the case of the proportion x of the amount of the first doping in Example 1, it can take all values within the range of 0.019 to 0.021.

[0024] Also, the ceramic substrate of the ceramic device may have a plurality of ceramic layers that may be the same or different, and internal electrodes provided between the ceramic layers. Here, the internal electrodes contain nickel as the main component.

[0025] Further, the ceramic device may be configured as a capacitor. In particular, the ceramic device may be configured as a multilayer capacitor. The multilayer capacitor includes a ceramic substrate having a plurality of ceramic layers and internal electrodes provided between the ceramic layers. The internal electrodes preferably contain nickel.

[0026] Manganese pyrophosphate contained in the ceramic material can obtain a densely sintered ceramic substrate at a relatively low sintering temperature of 1200°C or lower. Hereinafter, the densely sintered ceramic substrate shall refer to a substrate having a sintering density of 90% or more.

[0027] The inventor will explain the positive effect of manganese pyrophosphate, that is, manganese pyrophosphate as a sintering aid has already been congruently melted under reducing conditions at a temperature lower than 1100°C. Congruent melting means that manganese pyrophosphate becomes completely liquid at its so-called melting point but does not decompose. As a result, the melted manganese pyrophosphate is uniformly distributed in the ceramic substrate, thereby obtaining an extremely uniform and highly compressed ceramic substrate.

[0028] By lowering the sintering temperature with manganese pyrophosphate, grain growth during sintering of the ceramic can be suppressed, and the electrical and mechanical properties of the ceramic substrate can be improved.

[0029] Also, by lowering the sintering temperature, an internal electrode containing nickel can be used. This is because when the sintering temperature is low, the internal electrode containing nickel does not melt. Nickel has a lower cost compared to conventional internal electrode metals such as gold, silver, and palladium, so the cost of the ceramic element can be kept at a low level overall.

[0030] The ceramic material can be used as the main component of a ceramic substrate that is part of a capacitor, particularly a multilayer capacitor. Thereby, the capacitor can be miniaturized, provided with ESD resistance, and a multilayer capacitor having an internal electrode containing Ni can be provided. For this reason, the multilayer capacitor has high reliability and low cost.

[0031] Structural forms of 0603 type or less are regarded as small capacitor sizes. Also, a capacitor that is hardly affected by ESD refers to a capacitor having a structural form of 0603 type or less, a capacitance of less than 10 nF, and an ESD voltage exceeding 8 kV. A capacitor with ESD resistance preferably has a capacitance of 1 nF and an ESD voltage exceeding 20 kV. The ESD voltage is the voltage at which a load can be applied to the element without damage. The higher the ESD voltage, the higher the voltage at which a load can be applied to the element without damage.

[0032] The present invention also relates to a method for manufacturing a ceramic device. The method includes the following steps: Providing a base ceramic material represented by the general formula CTiO3, where C is the main component of the base ceramic material and the main component contains a third metal selected from the group of third metals consisting of calcium, strontium, and barium; Adding an additive containing Mn2P2O7, a first dopant containing a first metal, and / or a second dopant containing a second metal, and / or a compound containing Ti, and / or at least one first compound containing a fourth metal to the ceramic material, and mixing to obtain a mixture, where the first metal is selected from the group of first metals consisting of neodymium, praseodymium, cerium, and lanthanum, the second metal is selected from the group of second metals consisting of niobium, tantalum, and vanadium, the third metal is selected from the group of third metals consisting of calcium, strontium, and barium, and the fourth metal is selected from the group of fourth metals consisting of aluminum, nickel, and iron; Grinding the mixture to obtain a powder of the mixture; Manufacturing a ceramic green sheet from a powder of the mixture, Forming internal electrodes on the ceramic green sheet, Stacking the ceramic green sheets to obtain a green sheet laminate, Pressing the green sheet laminate to obtain a pressed green sheet laminate, Cutting the pressed green sheet laminate into individual pieces to obtain a raw material of the individual element, Decarbonizing the individual element to obtain a decarbonized element, Sintering the decarbonized element to obtain a sintered element, Annealing the sintered element to obtain a ceramic substrate, Coating and sintering the outer surface of the ceramic substrate with a metal coating to obtain a ceramic device.

[0033] Hereafter, a substance containing at least one first metal is regarded as a first dopant, and the first metal is a component of the first dopant.

[0034] Hereafter, a substance containing at least one second metal is regarded as a second dopant, and the second metal is a component of the second doping.

[0035] As the first dopant, at least one oxide of the first metal may be used. Here, the first metal is selected from the group of the first metals.

[0036] As the second dopant, at least one oxide of the second metal may be used. Here, the second metal is selected from the group of the second metals.

[0037] Further, a first and / or a second dopant may be added to the base ceramic material. Here, the first dopant contains at least two first metals, and the second dopant contains at least two second metals. In other words, the first dopant includes at least one component containing at least two different first metals. The first dopant may preferably include a first component and a second component. Here, the first component contains a first metal different from the first metal contained in the second component. The second dopant is the same as the first dopant, except that it contains a second metal instead of the first metal.

[0038] The main component of the base ceramic material may further contain at least two third metals.

[0039] Also, an additive may be added to the base ceramic material, and the additive contains at least aluminum and nickel. In other words, the additive may include a first compound containing at least aluminum and nickel. The additive may preferably include a first compound and a second compound. Here, the first compound contains nickel, the second compound contains aluminum, or vice versa.

[0040] Also, a metal-containing slurry containing nickel may be used to form the internal electrode.

[0041] Also, a laminate of the decarburized green sheets may be sintered at a temperature of 1200 to 1250 °C for a holding time of 1 to 5 hours. It is preferable to sinter the laminate of the decarburized green sheets at 1200 °C, 1250 °C, or a temperature therebetween for 4 hours.

[0042] In a preferred embodiment of the method for manufacturing the ceramic device, the laminate of the decarburized green sheets may be sintered in a reducing atmosphere. Hereinafter, the reducing atmosphere shall refer to an atmosphere that prevents oxidation of the ceramic material and the internal electrode containing nickel, particularly by oxygen in the air.

[0043] Also, the sintered element can be re-oxidized by annealing in air. For example, in a capacitor, this step can be used to set the electrical characteristics of the capacitor, such as the ESD resistance of the capacitor.

[0044] Also, the ceramic substrate may be coated with a passivation layer formed from glass. The passivation protects the ceramic substrate from external influences such as humidity and temperature changes.

[0045] Hereinafter, the present invention will be described in detail based on examples with reference to the accompanying drawings.

Brief Description of the Drawings

[0046]

Figure 1

[0047] The drawings and the dimensional ratios in the drawings are not drawn to scale.

Modes for Carrying Out the Invention

[0048] FIG. 1 shows a ceramic device having a ceramic substrate 1, the substrate having an internal electrode 2 provided therein and two metal coatings 3 attached to two opposing outer surfaces 1' of the ceramic substrate 1. Also, the ceramic substrate 1 has a passivation layer 4 formed from glass. The ceramic device is configured as a multilayer capacitor. The ceramic substrate has a composition formula La0,2Ba0, 194 Sr0, 776 Ti1O3* (Mn2P2O7) 0.01 Since it contains a ceramic material represented by, it corresponds to the combination of components in Example 1 shown in Table 1.

[0049] In one embodiment, a base ceramic material represented by the composition formula Ba0.2Sr0.8TiO3 is provided to manufacture a ceramic substrate. Lanthanum oxide as a first dopant, titanium oxide as a titanium-containing compound, and manganese pyrophosphate are added to the base ceramic material. The total of the proportions of the amounts of the base ceramic material, the first dopant, the titanium-containing compound, and manganese pyrophosphate is 100 mol%. Accordingly, the value of the proportion of the amount of the base compound is 97 mol%, the value of the proportion of the amount of the first dopant is 1 mol%, the value of the proportion of the amount of the titanium-containing compound is 1.5 mol%, and the value of the proportion of the amount of manganese pyrophosphate is 0.5 mol%. Then, the base compound, the first dopant, the titanium-containing compound, and manganese pyrophosphate are mixed and pulverized to obtain a powder of the mixture.

[0050] Using the powder of this mixture, a ceramic green sheet is manufactured, and an internal electrode is formed on these ceramic green sheets with a metal-containing paste containing nickel. In the next step, the flatly pressed ceramic green sheets are laminated to form a green sheet laminate, and pressure-bonded to obtain a pressure-bonded green sheet laminate. Subsequently, after the pressure-bonded green sheet laminate is separated into individual pieces, the separated elements are decarbonized at 600 °C and sintered at 1250 °C for 4 hours in a reducing atmosphere to obtain a ceramic substrate 1. In another step, two opposing outer surfaces 1' of the ceramic substrate 1 are coated with a metal coating 3. Finally, a passivation layer 4 formed from glass is applied to the ceramic substrate 1.

[0051] The present invention is not limited to the above embodiments. The ceramic material may particularly have a combination of components corresponding to Embodiments 2 to 7 in FIG. 1, but may also have a specific combination of components different from the combination of components in Embodiments 1 to 7 in FIG. 1. Here, Embodiments 1 to 7 are preferred. Also, the use of the ceramic material is not limited to capacitors.

Explanation of Reference Numerals

[0052] 1 Ceramic substrate 1' Outer surface 2 Internal electrode 3 Outer metal layer 4 Passivation layer

Claims

1. Molecular formula Mn 2 P 2 O 7 A ceramic material having a base compound represented by the general formula CTiO 3 and added with manganese pyrophosphate represented by the above as a sintering aid.

2. The ceramic material according to claim 1, wherein C is one or more selected from calcium, strontium, and barium.

3. Having a first doping selected from the group consisting of neodymium, praseodymium, cerium, and lanthanum, The ceramic material according to claim 1, wherein the first doping occupies the atomic position of C in the crystal lattice.

4. Having a second doping selected from the group consisting of niobium, tantalum, and vanadium, The ceramic material according to claim 1, wherein the second doping occupies the atomic position of Ti in the crystal lattice.

5. The ceramic material according to claim 1, containing an additive selected from aluminum, nickel, and iron.

6. A ceramic device having a ceramic substrate (1) containing the ceramic material according to claim 1 as a main component in a sintered state.

7. The general formula is A x B y C 1-x-v Ti 1-y+w O 3 * (Mn 2 P 2 O 7 ) z * D u is a ceramic material, where A is a first doping selected from the group of first metals consisting of neodymium, praseodymium, cerium, and lanthanum, B is a second doping selected from the group of second metals consisting of niobium, tantalum, and vanadium, C is the main component of the base ceramic material, and the main component is selected from the group of third metals consisting of calcium, strontium, and barium, and D is an additive containing at least one first compound, and the first compound contains a fourth metal selected from the group of fourth metals consisting of aluminum, nickel, and iron, x is the ratio of the amount of A, y is the ratio of the amount of B, v is the ratio of the amount of pores in A, w is the ratio of the amount of excess titanium, z is the Mn as a sintering aid 2 P 2 O 7 The ratio of the amount, u is the ratio of the amount of D, 0.0 ≦ x < 0.1, 0.0 ≦ y < 0.1, 0 ≦ v < 1.5 * x, 0 ≦ w < 0.05, 0.01 ≦ z < 0.1, A ceramic material to which the relationship of 0 ≦ u < 0.05 is applied.

8. A method for manufacturing a ceramic device, wherein C is the main component of the base ceramic material, and the main component contains a third metal selected from the group of third metals consisting of calcium, strontium, and barium, and providing the base ceramic material; General formula CTiO 3 represented by obtaining a green element before sintering containing the mixture; Add manganese pyrophosphate represented by the molecular formula Mn 2 P 2 O 7 to the base ceramic material and mix to obtain a mixture; A method for manufacturing a ceramic device including. The above-mentioned molecular formula Mn 2 P 2 O 7 The step of sintering the pre-sintered element to obtain a sintered element, wherein manganese pyrophosphate represented by acts as a sintering aid;

9. ​ General formula CTiO 3 When sintering a ceramic material containing a base ceramic material represented by General formula Mn 2 P 2 Use as a sintering aid for manganese pyrophosphate represented by O7.

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