JP4502741B2 - Multilayer ceramic capacitor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a multilayer ceramic capacitor and a method for producing the same, and in particular, is used for high-functional electronic devices such as personal computers and mobile phones, and extremely thin dielectric layers and internal electrode layers are alternately laminated, respectively. The present invention relates to a small-sized and high-capacity multilayer ceramic capacitor excellent in reliability such as a high-temperature load life and a manufacturing method thereof.

  In recent years, with the downsizing and higher functionality of electronic devices, the multilayer ceramic capacitors used for this purpose have been required to be smaller and have higher capacities. For this reason, the number of dielectric layers and internal electrode layers increased, and the dielectric layers themselves. In addition, as the characteristics of a multilayer ceramic capacitor, reliability such as capacity-temperature characteristics and high-temperature load life is improved. And as such a multilayer ceramic capacitor, what is disclosed by the following patent documents 1-3 is known, for example.

First, in the multilayer ceramic capacitor disclosed in Patent Document 1, in preparation of the dielectric ceramic, BaTiO ₃ and MgO are preliminarily calcined, and then various kinds of rare earth elements and acceptor elements are applied to the calcined powder. A method of adding an oxide is used. By adopting such a two-stage mixing method, even after firing, because of MgO previously dissolved, it enters into the BaTiO ₃ crystal particles of various oxides of rare earth elements and acceptor elements added later. It is described that the above-mentioned desired characteristics can be obtained as a result.

  In Patent Document 2, by forming a dielectric ceramic with two or more types of crystal particles having an average particle diameter of 0.1 to 0.3 μm and different capacity-temperature characteristics, the capacity-temperature characteristics are flat and the DC bias characteristics are achieved. It is described that an excellent multilayer ceramic capacitor can be obtained.

According to this publication, in a dielectric particle mainly composed of BaTiO ₃ , when a particle size becomes 1 μm or less, formation of a crystal particle called a core-shell structure, which realizes a flat capacity-temperature characteristic and an excellent DC bias characteristic, is realized. In this way, the dielectric particles having a particle size of 1 μm or less are further atomized to suppress the dielectric activity so that the flat capacitance-temperature characteristics and the excellent characteristics of the dielectric ceramic as a whole are excellent. DC bias characteristics are obtained.

In Patent Document 3, by using Ba _1−x Ca _x TiO _{3 in} which part of BaTiO ₃ constituting the dielectric ceramic is replaced with Ca, this also has flat capacitance temperature characteristics and excellent DC bias characteristics. It is described that it is obtained.
JP 2001-230149 A JP-A-9-241075 JP 2000-58378 A

However, since the multilayer ceramic capacitor disclosed in Patent Document 1 employs a preliminary process of pre-mixing BaTiO ₃ and MgO and calcining, the dielectric constant of the dielectric ceramic can be increased, In addition, the capacity temperature characteristic can satisfy the B characteristic (temperature range: −25 ° C. to 85 ° C., capacity change rate within ± 10%), but the capacity temperature characteristic is wide X7R (temperature range: −55). C.-125.degree. C., capacity change rate within ± 15%).

  Next, in the dielectric ceramic described in Patent Document 2, the relative permittivity increases only to about 2100 at most due to the atomization of the dielectric particles.

Also for the dielectric ceramic described in Patent Document 3, in Ba _1-x Ca _x TiO ₃ , the relative permittivity decreased greatly due to Ca substitution, and it was difficult to make the relative permittivity higher than 2000.

  In particular, the capacitor including the dielectric layer described in Patent Documents 1 to 3 has a low relative dielectric constant in an AC electric field strength range of 0.002 to 1 Vrms / μm.

  Therefore, even if the dielectric layer is thinned, the present invention has a high relative dielectric constant in the AC electric field strength range of 0.002 to 1 Vrms / μm and excellent reliability such as capacity-temperature characteristics and high-temperature load life. It is an object of the present invention to provide a small-sized and high-capacity multilayer ceramic capacitor and a manufacturing method thereof.

Multilayer ceramic capacitor of the present invention, the BaTiO ₃ particles (BMTL), together with _Ba 0.95 _Ca 0.05 TiO ₃ particles and (BMTH) coexist, mean an average particle size of the BMTL D L, the BMTH the particle size when D _H, and, together with a D L / D H = 1.1 4 ~ 1.17, the BMTL and the BMTH are both include rare earth elements, the concentration gradient of the rare earth element And a capacitor body in which a dielectric layer of 0.12 to 0.17 atomic% / nm and an internal electrode layer are alternately laminated from the particle surface to the inside of the particle, with the particle surface being the highest concentration. It is characterized by that.

According to the present invention, when two or more kinds of barium titanate particles having different Ca component concentrations coexist, BaTiO ₃ particles (BMTL) having a low Ca component concentration and a large average particle size can exhibit a high relative dielectric constant. At the same time, the temperature characteristics of relative permittivity can be flattened by the Ba _0.95 Ca _0.05 TiO ₃ particles having a high Ca component concentration. Further, these BaTiO ₃ particles (BMTL) and Ba _0.95 Ca _0.05 TiO by ₃ particles (BMTH) is complexed, can more flattened temperature characteristic of and specific dielectric constant at a higher dielectric constant AC electric field intensity range of 0.002~1Vrms / μm, yet low Ca component concentration BaTiO _{Since the three} particles and Ba _0.95 Ca _0.05 TiO ₃ particles having a high Ca component concentration coexist, the dielectric layer can be highly insulated.

In this case, in that the temperature characteristic of the high maintenance can dielectric constant of the dielectric constant can be flattened, the desirably an average particle diameter of BMTL and the BMTH are both at 7μm or less, Ri誘 conductive by the this Grain boundaries in the body layer can be increased, and the insulation of the entire dielectric layer can be improved .

Next, production method of the multilayer ceramic capacitor of the present invention, (a) an average particle size of BaTiO ₃ powder powder Contact good beauty flat Hitoshitsubu径of 0.05~0.5μm is smaller than B ATiO ₃ powder _{Ba 0.} preparing a ₉₅ Ca _0.05 TiO ₃ powder powder, (b) the BaTiO ₃ each powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder of MgO was added to the tentative at a temperature of 600 to 850 ° C. baked to, BaTiO ₃ calcined powder and _Ba 0.95 _Ca 0.05 TiO ₃ calcined powder preparing a, (c) the BaTiO ₃ calcined powder and _Ba 0.95 _Ca 0.05 TiO ₃ provisional and baked powder, and a rare earth element compound, a Mn CO _3, MgO and, an organic vehicle combined mixed to prepare a slurry, and forming the molding to the dielectric green sheet, (d) dielectric grease On the main surface of the sheet, forming an internal electrode pattern, and a step of forming a capacitor body forming body is fired by stacking a plurality of dielectric green sheets are formed (e) the internal electrode pattern It is characterized by comprising.

In preparation of the multilayer ceramic capacitor of the present invention, BaTiO ₃ having a raw material powder for forming the dielectric ceramic has an average particle size that is different at the stage of initial starting material, yet different sinterability and grain growth rate It uses a powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder, during firing, in order to suppress the reaction between these BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder, these both powder, previously, MgO and by solid solution partially at temperatures as low as 600 to 850 ° C., on the front surface layer near the BaTiO ₃ calcined powder and _Ba 0.95 _Ca 0.05 TiO ₃ calcined powder
By keeping a solid solution of MgO, from _Ba 0.95 _Ca 0.05 TiO ₃ calcined powder side containing Ca, can suppress the diffusion of Ca to BaTiO ₃ calcined powders side having no Ca, dielectric The coexistence state of the dielectric particles having different Ca component concentrations in the body layer can be maintained.

Further, according to the method to be a solid solution partially MgO in both raw material powder BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder were mixed with each other at the temperature of 600 to 850 ° C., rare earth added after It is also possible to suppress solid solution of elements and other additives to BaTiO ₃ calcined powder and Ba _0.95 Ca _0.05 TiO ₃ calcined powder .

In this case , the ratio of MgO added in step (b) is 30 to 60% of the total MgO added in steps (b) and (c) in terms of molar ratio, thereby enhancing the effect of adding MgO. It is Ru can. In particular, when the additive component is MgO, there is a large difference in the ion radius of BaTiO _{3 with} the Ba ion, so that the amount of ions dissolved in BaTiO ₃ can be reduced.

That is, when the M in _{B a 1-x M x TiO} 3 powder and Ca, for small elements in solid solution than the M as previously Mg in BaTiO _3, come to spread later Ca It is possible to suppress the diffusion of alkaline earth elements having a large ionic radius. In other words, the effect of adding MgO to the BaTiO ₃ powder in the present invention is that the alkali ion from the Ba _1-x M _x TiO ₃ powder side is increased as the element having a smaller ionic radius of the alkaline earth element added to the BaTiO ₃ powder is used. Diffusion of earth components can be suppressed .

(Multilayer ceramic capacitor structure)
The multilayer ceramic capacitor of the present invention will be described in detail based on the schematic sectional view of FIG. The multilayer ceramic capacitor of the present invention is configured by forming external electrodes 3 at both ends of a capacitor body 1. The external electrode 3 is formed, for example, by baking Cu or an alloy paste of Cu and Ni.

The capacitor body 1 is formed by alternately laminating dielectric layers 5 and internal electrode layers 7. The dielectric layer 5 is low Ca component concentration, and BaTiO ₃ particles 11 is dielectric particles composed mainly of Ba and Ti, are dielectric particles high Ca component concentration, Ba, and Ti as a main component It is composed of Ba _0.95 Ca _0.05 TiO ₃ particles 13 and a grain boundary phase 15, and the thickness is preferably 4 μm or less, particularly 3 μm or less in terms of increasing capacitance, while maintaining high insulation. In this respect, 0.5 μm or more, particularly 1 μm or more is desirable. Furthermore, in the present invention, it is more desirable that the thickness variation of the dielectric layer 5 is within 10% in order to stabilize the capacitance variation and capacitance temperature characteristics.

  The internal electrode layer 7 is preferably a base metal such as Ni or Cu from the viewpoint that the manufacturing cost can be suppressed even if the internal electrode layer 7 is made highly laminated, and particularly Ni is more preferable from the viewpoint of simultaneous firing with the dielectric layer of the present invention. . The thickness of the internal electrode layer 7 is preferably 2 μm or less on average.

In particular, according to the present invention, the dielectric layer 5, the BaTiO ₃ particles _(BMTL), along with and the Ba _{0.95 Ca} 0.05 TiO ₃ particles (BMTH) coexist, the average particle diameter of BMTL D L, the BMTH when the average particle diameter D _H, and, it is important that the D L / D H = 1.1 4 ~ 1.17.

When the Ca component concentration of BMTL is 0.3 atomic% or more, while the Ca component concentration of BMTH is 0.4 atomic% or less, the Ca component concentrations of BMTL and BMTH overlap, and the dielectric due to the Ca concentration difference The characteristics of the relative dielectric constant and temperature characteristics of the body particles are difficult to express, and the coexistence effect of both the dielectric particles of BMTL and BMTH is reduced. Further, when the Ca component concentration of BMTH is 2.5 atomic% or more, the decrease in the relative dielectric constant of BMTH becomes large.

Furthermore, D when L / D H ratio is less than 1.1 is, 0.002~1Vrms / μm Ri ratio Na large increase in the dielectric constant in an alternating current electric field, whereas, if the DL / DH ratio is greater than 2 However, the capacity-temperature characteristic becomes large. And BL / BH = 1... In terms of further improving the relative dielectric constant and its temperature characteristics . 14-1. 17 is good .

Further, Ca component in solid solution in BMT H having a high proportion of Ca component concentration in the present invention has a high rate of solid solution to B ATiO _3, that the dielectric constant of BaTiO ₃ increased and its temperature characteristics improved And Ca is good .

  Further, according to the present invention, the average particle diameters of BMTL and BMTH are both 0.7 μm or less, particularly 0.6 μm or less, which is more desirable in terms of achieving high insulation and 0 in terms of increasing the relative dielectric constant. .2 μm or more is desirable.

  Furthermore, the dielectric layer 5 has a thickness of 4 μm or less, and the internal electrode layer 7 is made of a base metal (Cu, Ni, Co, etc.), in particular, the sintering temperature of the metal matches the sintering temperature of the dielectric material. Ni is preferable in this respect.

Further, the dielectric layer 5 that put the present invention, the concentration gradient of the rare earth element is the particle surface from the crystal grain surface and grain boundary phases 15 as the highest concentration toward inside of the grain from 0.12 to 0.17 atomic% / nm Have .

  That is, when the concentration gradient of the rare earth element is in such a condition, it is possible to obtain a capacitor that satisfies the X7R standard as a capacity temperature characteristic as well as an improvement in relative permittivity and high temperature load life.

  Here, as the rare earth element in the present invention, at least one of La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Y, Er, Tm, Yb, Lu, and Sc is preferable, and Y is particularly preferable. preferable.

Furthermore, the present invention
BaTiO ₃ grain transducer in, as before mentioned, by calcination, but in which Mg is dissolved in the surface region, a concentration gradient of Mg in the surface region of the BaTiO ₃ grains element is solid diffusion of the rare earth element From the viewpoint of enhancing the suppression of dissolution, it is desirable that the grain boundary portion is at a high concentration side and is 0.003 atomic% / nm or more, preferably 0.01 atomic% / nm or more toward the inside of the grain.

(Manufacturing method)
The production method of the multilayer ceramic capacitor of the present invention is as follows: (a) BaTiO ₃ powder having an average particle diameter of 0.05 to 0.5 μm and Ba _0.95 Ca _0.05 TiO having an average particle diameter smaller than that of the BaTiO ₃ powder. ₃ preparing a flour powder, and calcined at (b) was added to MgO to each of the BaTiO ₃ powder and the Ba _0.95 Ca _0.05 TiO ₃ powder, temperature of 600 to 850 ° C., BaTiO ₃ it is preparing a calcined powder and _Ba 0.95 _Ca 0.05 TiO ₃ calcined powder, characterized by including the. Here, BaTiO ₃ with respect to the powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder was calcined at a temperature of 600 to 850 ° C., MgO is BaTiO ₃ powder and _Ba 0.95 _{Ca 0.05} It is important to prepare a calcined powder that is formed as a solid solution on the surface of both TiO ₃ powders , and MgO is present on the surface of both BaTiO ₃ powder and Ba _0.95 Ca _0.05 TiO ₃ powder. you are.

The BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder of the main raw material used here, the powder is preferably obtained by hydrothermal synthesis because of high crystallinity narrow particle size distribution, the average particle The diameter is preferably 0.2 μm or more and 0.4 μm or less. In addition, the specific surface area of such a fine powder is preferably 1.7 to 6.6 (m ² / g). On the other _hand, the average particle size of Ba _{0.95 Ca} 0.05 TiO ₃ powder, it is important that less than B ATiO ₃ powder, 0.04～0.4Myuemu, especially in 0.15~0.35μm More preferably.

Further , in the present invention, for example, BaTiO ₃ powder in which MgO is solid-dissolved on the surface is formed by calcining at a low temperature , and due to the reason that the AC electric field characteristics after firing are enhanced, a high reaction is accompanied by appropriate grain growth. Therefore, it is desirable to define the average particle size as well as the specific surface area within the above range.

The calcination temperature in the production method of the multilayer ceramic capacitor of the present invention, the reason of suppressing dissolution of MgO in BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder powder that M gO surfaced solid solution, The temperature is preferably 850 ° C. or lower, particularly 750 ° C. or lower. On the other hand, 600 ° C. or higher, particularly 650 ° C. or higher is preferable for ensuring the diffusion and solid solution of MgO on the surface of the BaTiO ₃ powder. The average particle size of M gO powder, in that coating rate to BaTiO ₃ powder surface is increased, less desirable 0.3 [mu] m. In the present invention, by using a BaTiO ₃ powder powder that was calcined in this manner beforehand MgO, it is possible to suppress the diffusion solid solution of a rare earth element, grain growth can be suppressed.

In contrast, the BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder, the calcining temperature for a solid solution of M g O is higher than 850 ° C., an alkaline earth at grain boundaries near Since elemental oxides tend to diffuse and dissolve, and thus rare earth elements diffuse and dissolve, dielectric particles having a low Ca component concentration and containing barium titanate as a main component are likely to grow. The temperature characteristics of the capacitance cannot satisfy the desired characteristics.

Further, with respect to the process of the present invention, the BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder, without the processing to solid solution of M gO above, BaTiO ₃ powder and _{Ba 0.95} Ca _{0.05 When} added together with additives such as TiO ₃ powder _and rare earth elements _, it is difficult to form a solid solution of MgO on the surface layer of BaTiO ₃ powder , so that Ba _1-x M _x The diffusion of M component and the like from TiO ₃ increases, the original relative dielectric constant of BaTiO ₃ cannot be maintained, and the capacitance decreases. In addition, grain growth tends to occur. Ba _0.95 Ca _0.05 TiO ₃ is desirable because it can increase the dielectric constant and flatten the capacitance-temperature characteristics.

The ratio of MgO to be added in step (b) of this process is the molar ratio is preferably 30% to 60% of oxides of the total alkaline earth element added in step (b) and (c) step, alkali arbitrariness preferred is MgO as the earth element. The dielectric layer that put the present invention are those comprising a glass phase, a glass phase, the glass powder of Si-Li-Ca system is preferred.

Next, (c) In the step, a BaTiO ₃ calcined powder, and _B a _{0.95 Ca} 0.05 TiO ₃ calcined powder, a rare earth element compound, Mn compound, a and remaining MgO, organic vehicle Are mixed at a predetermined ratio to prepare a slurry, which is then molded to form a dielectric green sheet. The molding using the above-described slurry is preferably a sheet molding method such as a die coater, and the thickness of the dielectric green sheet formed by such a molding method is preferably 5 μm or less, and particularly preferably 4 μm or less.

Next, in step (d), an internal electrode pattern is formed on the main surface of the dielectric green sheet. The internal electrode pattern is formed, for example, by screen printing of a base metal powder such as Ni or Cu that is pasted together with an organic resin or a solvent. The thickness of the internal electrode pattern is preferably smaller than the thickness of the dielectric green sheet and 4 μm or less in terms of reducing the level difference on the dielectric green sheet.

Next, in step (e), a plurality of dielectric green sheets on which internal electrode patterns are formed are stacked to form a capacitor body molded body. Thereafter, the capacitor body 1 is heated to 40-80 ° C./h in the atmosphere. The binder removal treatment is performed at a temperature rising rate of 400 to 500 ° C., and then the temperature rising rate from 500 ° C. is set to 100 to 400 ° C./h in a reducing atmosphere, and firing is performed at a temperature of 1100 to 1300 ° C. for 2 to 5 hours. Subsequently, cooling is performed at a temperature drop rate of 80 to 400 ° C./h, and reoxidation is performed at 750 to 1100 ° C. in an air atmosphere.

Finally, an external electrode paste is applied to both end faces of the fired capacitor body 1 and baked in nitrogen, whereby the external electrode 3 is formed and the multilayer ceramic capacitor of the present invention can be obtained.

The multilayer ceramic capacitor of the present invention was produced as follows. First, with respect to 100 mol parts of BaTiO ₃ (BT) + (Ba _0.95 Ca _0.05 ) TiO ₃ (BCT) having an average particle diameter shown in Table 1, 0.25 mol parts of MgO are weighed sufficiently. Mix and heat at the temperature shown in Table 1 for 2 hours. Next, the amount of rare earth elements shown in Table 1 and 0.3 mol part of MnCO ₃ with respect to 100 mol parts of the mixed powder of BaTiO ₃ + (Ba _0.95 Ca _0.05 ) TiO ₃ calcinated. , 0.25 mol part of MgO was mixed.

Next, 0.5 parts by mass of additive components composed of Li ₂ O, SiO ₂ and CaO are mixed with 100 parts by mass of BaTiO ₃ calcined powder + (Ba _0.95 Ca _0.05 ) TiO ₃ calcined powder. The mixed powder was wet pulverized by a ball mill using ZrO ₂ balls having a diameter of 5 mmφ, and an organic binder was added to prepare a slurry. Next, using this slurry, a dielectric green sheet having a thickness of 4 μm was prepared by a doctor blade.

Next, the capacitor body obtained by firing was barrel-polished, and then an external electrode paste containing Cu powder and glass was applied to both ends thereof, followed by baking in nitrogen at 850 ° C. to form external electrodes. . Then, using an electrolytic barrel machine, Ni and Sn plating were sequentially performed on the surface of the external electrode to produce a multilayer ceramic capacitor.

  Next, 388 dielectric green sheets on which internal electrode patterns are formed are stacked, and 20 dielectric green sheets on which internal electrode patterns are not formed are stacked on the upper and lower surfaces, and are integrated using a press. A laminate was obtained.

  Thereafter, the base laminate was cut into a lattice shape to produce a capacitor body molded body of 2.3 mm × 1.5 mm × 1.5 mm.

Next, this capacitor body molded body was subjected to binder removal treatment at 500 ° C. in the atmosphere at a temperature increase rate of 50 ° C./h, and the temperature increase rate from 500 ° C. was 1240 ° C. (Oxygen partial pressure 10 ⁻¹¹ atm) calcination for 2 hours, cooling to 800 ° C. at a temperature decrease rate of 200 ° C./h, followed by re-oxidation treatment at 800 ° C. for 4 hours in air atmosphere, 200 ° C./h The capacitor body was manufactured by cooling at a temperature drop rate of. The thickness of the dielectric layer was 2.3 μm.

  Next, the fired capacitor body was barrel-polished, and then an external electrode paste containing Cu powder and glass was applied to both ends thereof, and baked in nitrogen at 850 ° C. to form external electrodes. Then, using an electrolytic barrel machine, Ni and Sn plating were sequentially performed on the surface of the external electrode to produce a multilayer ceramic capacitor.

  Next, the capacitance and dielectric loss of these samples, which were the produced multilayer ceramic capacitors, were measured at a frequency of 1.0 kHz and an input signal level of 0.5 V using an LCR meter 4284A. The relative dielectric constant was calculated from the capacitance, the effective area of the internal electrode layer, and the thickness of the dielectric layer.

  Subsequently, the temperature characteristics of the capacitance were measured in a range of −55 to 125 ° C. with reference to the capacitance at 25 ° C. The high temperature load test was performed for 1000 hours under the conditions of a temperature of 125 ° C. and a voltage of 9.45 V, and the change in insulation resistance was measured for 30 samples. In this case, a non-defective one was considered good. In addition, the crystal particle diameter and its variation were measured using photographs taken with an electron microscope by the intercept method.

  In addition, the presence of rare earth elements in the crystal grains constituting the dielectric layer was evaluated using a transmission electron microscope and limited-field electron diffraction image analysis on a cross-polished sample.

Moreover, regarding the Ca concentration, an arbitrary place in the vicinity of the central portion was analyzed using a transmission electron microscope and EDS. At that time, those having a Ca concentration higher than 0.3 atomic % (rounded to the second decimal place) were used as dielectric particles having a high Ca concentration. This analysis was performed on 100 to 150 main crystal particles.

Rights Hitoshitsubu diameter of the crystal grains in the sample of the present invention, BaTiO ₃ particles are dielectric particles mainly composed of low Ca concentration Ba, and Ti (BMTL) is 0.4 .mu.m, a high Ca concentration, Ba and Ti Ba _0.95 Ca _0.05 TiO ₃ (BMTH), which is a dielectric particle containing as a main component, was 0.3 μm. Further, variation in the flat Hitoshitsubu diameter thereto BMTL and BMT H co (CV value) was 0.5 or less.

As a comparative example, the raw material particle size is 0.4 μm for BaTiO ₃ and 0.35 μm for (Ba _0.95 Ca _0.05 ) TiO ₃ , and the calcining temperature of MgO to BaTiO ₃ is 1150 ° C. The other additive compositions and procedures were the same as those in the process of the present invention (No. 1). In addition, as a comparative example, only BaTiO ₃ powder or (Ba _0.95 Ca _0.05 ) TiO ₃ powder was used, and the other additive compositions and procedures were the same as those of the above-described process of the present invention. (No. 2, 3)

  As is apparent from Tables 1 and 2, sample Nos. Produced using the production method of the present invention. 4-No. 11, the relative dielectric constant was 3100 or more in the range of the AC electric field of 0.02 to 1 Vrms / μm, the capacitance-temperature characteristic satisfied the X7R standard, and the insulation resistance also satisfied 10 GΩ.

  On the other hand, sample No. 1 calcined at 1150 ° C. In No. 1, DL / DH = 0.9, the temperature characteristics of the capacitance were increased, and the X7R characteristics were not satisfied. Also, BMTL alone did not satisfy the X7R characteristics. In addition, in the case of dielectric particles of BMTH alone, the insulation resistance was as low as 0.2 GΩ.

It is a schematic sectional drawing of the multilayer ceramic capacitor of this invention.

Explanation of symbols

1 ... capacitor body 5 ... dielectric layer 7 ... internal electrode layer 11 · · M a low concentration, BaTiO ₃ particles 13 · · M concentration of a dielectric particles composed mainly of Ba and Ti Ba _0.95 Ca _0.05 TiO ₃ particles 15 which are high dielectric particles mainly composed of Ba and Ti 15 .. grain boundary phase

Claims (3)

BaTiO ₃ and particles (BMTL), along with and the _Ba 0.95 _Ca 0.05 TiO ₃ particles (BMTH) coexist, the average particle size of the BMTL the D L, the average particle size of the BMTH D _H, and Occasionally, as well as a D L / D H = 1.1 4 ~ 1.17, the BMTL and the BMTH are both include rare earth elements, the concentration gradient of the rare earth element, as the highest concentration of particle surfaces, A multilayer ceramic capacitor comprising a capacitor body in which dielectric layers of 0.12 to 0.17 atomic% / nm and internal electrode layers are alternately stacked from the particle surface to the inside of the particle. . The multilayer ceramic capacitor according to claim 1, wherein the average particle size of the BMTL and the BMTH are both at 0.7μm or less. A method of multilayer ceramic capacitor according to claim 1 or claim 2, (a) an average particle size of the BaTiO ₃ powder powder Contact good beauty flat Hitoshitsubu径of 0.05 to 0.5 [mu] m B ATiO ₃ powder preparing a small _Ba 0.95 _Ca 0.05 TiO ₃ powder powder than, MgO is added to each of (b) the BaTiO ₃ powder and _Ba 0.95 _Ca 0.05 TiO ₃ powder, 600 and calcined at a temperature of 850 ° C., preparing a BaTiO ₃ calcined powder and _Ba 0.95 _Ca 0.05 TiO ₃ calcined powder, (c) the BaTiO ₃ calcined powder and _{Ba 0.95} Ca and _0.05 TiO ₃ calcined powder, a rare earth element compound, a Mn CO _3, and forming the MgO, and an organic vehicle combined slurry was prepared by mixing, molding and a dielectric green sheet (D) the dielectric green sheet on a main surface, forming a step of forming an internal electrode pattern, a capacitor body forming body by stacking a plurality of dielectric green sheets are formed (e) the internal electrode pattern And a step of firing. A method of producing a multilayer ceramic capacitor, comprising:

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