KR20080073174A - Dielectric compositions for y5v type multilayer ceramic chip capacitors, and manufacturing method thereof - Google Patents

Abstract

A dielectric composition is provided to prevent crack which often occurs in chips produced from the conventional Y5V dielectric ceramic composition, and to improve IR falling. A dielectric composition for Y5V type multi-layer ceramic chip capacitors is obtained by adding predetermined amounts of at least two selected from Mn_(1+delta)TiO_3(0<delta<=0.05), BiVO4, and B-silicate glass frit to a composition of (Ba_(1-x)Ca_x)_m(Ti_(1-y)Zr_y)O_3+zY_2O_3(wherein, 0.01<=x<=0.08, 0.17<=y<=0.24, 0.001<=z<=0.004, and 1<=m<=1.04). A method for preparing the dielectric composition includes the steps of: mixing raw materials comprising BaCO3, CaCO3, TiO2, and ZrO2, and calcining the mixture; mixing the powder obtained by the calcination with Mn_(1+delta)TiO_3, BiVO4, B-silicate glass frit, and Y2O3, milling and drying the mixture; and adding a small amount of a binder to the dry powder, molding the admixture into a predetermined form, sintering and re-oxidizing the molded material.

Description

Dielectric Compositions for YLC with Excellent 제조 5Ｖ Properties and Manufacturing Method Thereof {Dielectric Compositions for Y5V Type Multilayer Ceramic Chip Capacitors, and Manufacturing Method Thereof}

1 is a manufacturing process chart of the excellent MLCC dielectric composition Y5V characteristics according to an embodiment of the present invention.

2 is a manufacturing process chart of the MLCC dielectric composition excellent in the Y5V characteristics according to an embodiment of the present invention.

3 is a manufacturing process chart of the excellent MLCC dielectric composition Y5V characteristics according to an embodiment of the present invention.

4 is a particle size distribution and SEM photograph of Mn _{1 + δ} TiO ₃ added to the preparation of the MLCC dielectric composition of the present invention.

5 is a particle size distribution and SEM photograph of BiVO ₄ added to the preparation of the MLCC dielectric composition of the present invention.

6 is a particle size distribution and SEM photographs of B-Silicate glass frit added to the production of the MLCC dielectric composition of the present invention.

7 is a particle size distribution diagram of BCTZ powders prepared by mixing and grinding BaCO ₃ , CaCO ₃ , TiO ₂ , and ZrO ₂ .

8 is a graph showing the XRD pattern after drying and calcining the BCTZ powder of FIG.

FIG. 9 is a SEM photograph of particle size distribution and particle size of Y5V powder mixed and crushed with an additive to the BCTZ powder of FIG. 7.

10 is a SEM image of particle size distribution and particle size of Y5V powder prepared using BaTiO ₃ .

FIG. 11 is a SEM photograph of particle size distribution and particle size of Y5V powder prepared using BCTZ prepared by coprecipitation.

12 is a SEM photograph showing the surface microstructure of a specimen prepared by the method of Example 2-4 using the Y5V powder prepared in Example 2-1.

FIG. 13 is a graph showing a capacitor temperature coefficient (TCC) of Y5V powder prepared using BaCO _3. FIG.

FIG. 14 is a graph showing capacitor temperature coefficients of Y5V powder prepared using BaTiO ₃ .

FIG. 15 is a graph showing capacitor temperature coefficients of Y5V powder prepared using BCTZ prepared by coprecipitation.

The present invention relates to a dielectric composition for a Y5V multilayer chip capacitor (MLCC) using Ni as an internal electrode, and more specifically, an additive Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05) and B-Silicate glass frit, BiVO. _{The present} invention relates to a dielectric ceramic composition for MLCC having excellent Y5V characteristics, and a method of manufacturing the same, characterized by improving cracking and IR falling, which are commonly generated in a chip manufactured by using an existing Y5V dielectric ceramic composition by optimizing the amount of ₄ added.

MLCCs are used in automobiles, computers, VCRs, and the like, and their use is increasing in mobile communication devices, which have recently increased in demand. Therefore, high dielectric constant materials for the production of MLCC having excellent characteristics are being developed, among which (Ba _1-xy Ca _x Sr _y ) _m (Ti _1-z Zr _z ) O ₃ (hereinafter, BCSTZ), (Ba _1- Multicomponent BaTiO ₃ -based composite perovskites, such as _x Ca _x ) _m (Ti _1-z Zr _z ) O ₃ (hereinafter BCTZ), are generally known as high-k materials exhibiting Y5V temperature characteristics.

The composition of the conventional barium titanate solid solution for Ni-F MLCC is (Ba _1-xy Ca _x Sr _y ) _m (Ti _1-z Zr _z ) O ₃ , (Ba _1-x Ca _x ) _m (Ti _1-z Zr _z M ≥ 1 was required to maintain the reduction resistance of the insulation resistance when firing the reducing atmosphere with) O ₃ . In addition, after synthesizing BCSTZ or BCTZ, a barium titanate solid solution for improving electrical characteristics, an acceptor that has specific resistance to reducing resistance by trapping delocalized electrons by oxygen vacancies generated during firing of reducing atmosphere. And a donor added for improving the accelerated life, and a sintering aid such as SiO ₂ and NiO. The dielectric properties of the barium titanate solid solution have a room temperature dielectric constant of 10000 or more, and the phase transition temperature satisfies the Y5V temperature characteristic at around 0 to 25 ° C.

However, in the case of the MLCC using Ni as an internal electrode, Ni is oxidized when the binder is pyrolyzed in an air atmosphere to exist in the form of NiO, and this NiO diffuses into a barium titanate solid solution to change dielectric properties. In particular, as the size of the capacitor increases along with the miniaturization, the thickness of the dielectric layer becomes thinner, so the influence of NiO on the dielectric layer becomes an important problem. Currently, the solid solution limit of NiO in BaTiO ₃ is reported to be 0.6 ~ 1.0% by weight, but studies on the Ni solid solution limit and its behavior in the barium titanate solid solution composition satisfying the dielectric properties of Y5V MLCC have not been reported yet. .

In addition, NiO, SiO ₂ and additives are mixed with the BCSTZ or BCTZ powders for the production of MLCCs. The uniform mixing of will be essential.

However, BCSTZ or BCTZ powders are prepared by the solid phase method of mixing, calcining, and pulverizing raw materials, and molding, laminating, compacting, and final heat treatment of the slurry mixed with additives, sintering aids, binders, plasticizers, and solvents. In the conventional MLCC manufacturing method that passes through, when the additives, the binder, and the solvent are mixed, it is difficult to uniformly mix the elements due to the characteristics of the solid phase synthesis method. Due to this, there are problems such as segregation due to heterogeneous mixing of each additive, such as local presence of secondary phase or partial unreacted material after final heat treatment, cracking and IR falling phenomenon during chip manufacturing. There was a problem that the production of MLCC having a difficulty was difficult.

Accordingly, the present invention is to solve the above-described problems of the prior art, by adding a predetermined amount of Mn _{1 + δ} TiO ₃ , B-Silicate glass frit, BiVO ₄ and the like to the BCTZ base composition while minimizing the reduction of the dielectric constant and excellent insulation Solid solution composition for MLCC having excellent Y5V characteristics using Ni as an internal electrode, and BaTiO ₃ prepared by the oxalate method having nano-sized particles, or (Ba _1-x , Ca _x ) _m manufactured by the coprecipitation method. To provide a method for preparing a dielectric ceramic composition for MLCC having excellent dielectric properties, such as the preparation and addition method, the amount of additives in the step of synthesizing the Y5V powder prepared using (Ti _1-y , Zr _y ) O ₃ It is done.

The present invention for achieving the above object, (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ + zY ₂ O ₃ (0.01≤ x≤0.08, 0.17≤y≤0.24, 0.001≤ z≤0.004 and 1≤m≤1.04) as the basic composition, and as an additive, two or more kinds of Mn _{1 + δ} TiO ₃ (0 <δ≤0.05), B-Silicate glass frit, and BiVO ₄ are added. The present invention relates to a dielectric ceramic composition for MLCC having excellent Y5V characteristics using Ni as an internal electrode, and a method of manufacturing the same.

In addition, the present invention includes a method of preparing by varying starting materials in preparing (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ , in detail BaCO ₃ , TiO of FIG. 1. ₂ , method of using BaTiO ₃ prepared by the hydroxide method of Figure 2, method of using (Ba _{1 - x} Ca _x ) _m (Ti _{1 - y} Zr _y ) O ₃ prepared by the coprecipitation method of FIG. This includes.

Specifically, the method using BaCO ₃ , TiO ₂ , after mixing the raw material consisting of BaCO ₃ , CaCO ₃ , TiO ₂ and ZrO ₂ , calcining it; Mixing Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05), BiVO ₄ , B-Silicate glass frit and Y ₂ O ₃ to the powder obtained by calcination, then grinding and drying; And adding a small amount of a binder to the dry powder and molding, followed by sintering and reoxidation.

In addition, the method of using BaTiO ₃ prepared by the oxalate method, BaTiO ₃ and BaCO ₃ prepared by the oxalate method, CaCO ₃ and ZrO ₂ mixed with a raw material, and then calcining it; Mixing Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05), BiVO ₄ , B-Silicate glass frit and Y ₂ O ₃ to the powder obtained by calcination, then grinding and drying; And adding a small amount of the binder to the dry powder and shaping, followed by sintering and reoxidation.

In addition, the method using (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ prepared by the coprecipitation method is (Ba _1-x Ca _x ) _m (Ti _1-y prepared by the coprecipitation method. Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05) is added to Zr _y ) O ₃ , mixed, dried and calcined; Mixing BiVO ₄ , B-Silicate glass frit, and Y ₂ O ₃ to the powder obtained by calcination, then grinding and drying them; And adding a small amount of a binder to the dry powder and molding, followed by sintering and reoxidation.

In the above production method, the sintering and reoxidation is not particularly limited, but the sintering is sintered for 1 to 3 hours at an atmosphere condition of 1.5% H ₂ at a temperature of 1100 to 1300 ℃, the reoxidation is 900 to 1000 ℃ It is preferable to re-oxidize for 2 to 4 hours under conditions of 20 ppm of O ₂ partial pressure at temperature.

Mn _{1 + δ} TiO ₃ powder of the additives added in the preparation of the dielectric ceramic composition for MLCC is not particularly limited, but MnCO ₃ and TiO ₂ is quantified to Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05) After that, the mixture is mixed, and calcined at a temperature of 900 to 1000 ° C., which is preferably prepared by grinding and drying it.

In addition, the B-Silicate glass frit powder in the additive is not particularly limited, but after drying by mixing SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , Li ₂ CO ₃ , BaCO ₃ , CaCO ₃ and SrCO ₃ , It is preferable to melt by melting at a temperature of 1500 to 1700 ℃, which is prepared by grinding and drying.

In addition, the BiVO ₄ powder in the additive is not particularly limited thereto, but Bi ₂ O ₃ and V ₂ O ₅ are quantified to be BiVO ₄ , and then mixed, calcined and dried at a temperature of 600 to 700 ° C. It is preferable to manufacture by.

Hereinafter, the present invention will be described in detail through examples.

Example

Example  One : Preparation of Additives

Additives Mn _{1 + δ} TiO ₃ , BiVO ₄ and B-silicate glass frit, which were added when the dielectric ceramic composition for MLCC was prepared, were prepared.

Example  1-1 : Mn _{One + δ} TiO ₃ Manufacture

MnCO 3 and TiO ₂ were quantified to Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05), and then mixed with a ball-mill for 20 hours. The mixture was dried and then calcined at 900 ° C. for 2 hours. The calcined powder was pulverized again to a particle size of 0.9 μm or less based on an index 1.8 based on a particle size analyzer of Horiba LA-910 Model using a ball mill. The particle size distribution and SEM at this time are as shown in FIG.

Example  1-2 : BiVO ₄ Manufacture

Bi2O3 and V2O5 were quantified to BiVO4 and mixed with a ball mill for 20 hours. The mixture was dried and then calcined at 600 ° C. for 2 hours. The calcined powder was pulverized to a particle size of 0.9 μm or less with a particle size analyzer of Horiba LA-910 Model using a ball mill, and then dried. The particle size distribution and SEM at this time are as shown in FIG.

Example  1-3 B- Silicate glass frit Manufacture

SiO ₂ , B ₂ O ₃ , Al ₂ O ₃ , Li ₂ CO ₃ , BaCO ₃ and CaCO ₃ were mixed with a ball mill for 10 hours, dried and melted at 1600 ° C. The glass solution was quenched by quenching the melted solution. After coarsely pulverizing the prepared glass frit, the ball mill was pulverized to a particle size of 0.65 μm or less based on an index of 1.16 using a particle size analyzer of Horiba LA-910 Model, and dried. The particle size distribution and SEM at this time are as shown in FIG.

Example 2 : Preparation of high dielectric constant material with Y5V characteristics

Example  2-1 : BaCO ₃ Using Y5V  Preparation of Dielectric Powder

BaCO ₃ , CaCO ₃ , TiO ₂ and ZrO ₂ having a purity of 99.5% or more were quantified to be (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ , and then bead-mill ) Was mixed and pulverized so that the particle size was 0.70 μm or less (see FIG. 7). The mixture was dried with a spray dryer and then calcined at 1140 ° C. for 4 hours. XRD analysis results of the calcined powder is shown in FIG.

Y ₂ O ₃ and Mn _{1 + δ} TiO ₃ , BiVO ₄ , and B-Silicate glass frit prepared in Example 1 were added to the calcined BCTZ powder as an additive and preliminarily mixed for 2 hours using a high speed dissolver. After grinding by grinding with 1, 2 and 3 passes with a bead mill, each powder was dried with a spray dryer to obtain a Y5V dielectric powder. The particle size distribution and SEM of the Y5V dielectric powder dried at 2 passes are shown in FIG. 9.

Example  2-2 Fisheries BaTiO ₃ Using Y5V  Preparation of Dielectric Powder

BaTiO ₃ and BaCO ₃ , CaCO ₃ and ZrO ₂ prepared by the oxalate method were quantified to be (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ , which was then particle size 0.70 μm or less. It was mixed and ground to be The mixture was dried with a spray dryer and then calcined at 1100 ° C. for 4 hours.

Y ₂ O ₃ and Mn _{1 + δ} TiO ₃ , BiVO ₄ , and B-Silicate glass frit prepared in Example 1 were added to the calcined BCTZ powder as an additive and preliminarily mixed for 2 hours using a high speed dissolver. After grinding by grinding with 1, 2 and 3 passes with a bead mill, each powder was dried with a spray dryer to obtain a Y5V dielectric powder. The particle size distribution and SEM of the Y5V dielectric powder dried at 2 passes are shown in FIG. 10.

Example  2-3 : Copulation ( Ba _{One - x} Ca _x ) _m ( Ti _{One - y} Zr _y ) O ₃ Using Y5V  Preparation of Dielectric Powder

Mn _{1 + δ} TiO ₃ prepared in Example 1 was added to (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ prepared by coprecipitation and mixed with a high speed dissolver for 2 hours. 1 pass using a mill and then dried in a spray dryer and calcined at 1050 ℃ for 4 hours.

Y ₂ O ₃ and BiVO ₄ , B-Silicate glass frit prepared in Example 1 were added to the calcined powder, and a preliminary mixing was performed for 2 hours by high speed disslover, followed by bead mill 1 pass, 2 pass and After milling three passes, each powder was dried in a spray dryer to obtain a Y5V dielectric powder. The particle size distribution and SEM of the 2 pass-dried Y5V dielectric powder are shown in FIG. 11.

Example 2-4 Preparation of Specimen

A small amount of binder was added to each of the Y5V dielectric powders prepared in Examples 2-1 to 2-3 and molded into a thickness of about 1.3 mm in a 15 mm cylindrical mold, followed by sintering at 1220 ° C. under an atmosphere condition of 1.5% H ₂ for 2 hours and 940. Specimens were prepared by reoxidation at 2 ° C. for 20 hours at 20 ppm oxygen partial pressure. The surface microstructure of the specimen using the Y5V powder prepared in Example 2-1 is shown in FIG. 12.

The specimen prepared as described above was polished to have a thickness of about 1 mm, and the dielectric properties were measured after attaching the In—Ga electrode, which is shown in FIGS. 13 to 15, respectively. As shown in FIGS. 13 to 15, it was found that the temperature coefficient (TCC) of the capacitor satisfies the Y5V characteristic because it is within a range of −80 to 22%. The above manufacturing process is as shown in FIGS. 1 to 3. .

Example  3 : BCTZ  Comparison of Dielectric Properties According to Manufacturing Method and MLCC Chip Manufacturing

Y5V powder was prepared using BCTZ prepared according to the methods of Examples 2-1 to 2-3, and the experimental results according to the respective methods were compared. The dielectric constant, dielectric loss, insulation resistance (IR), density and sintering temperature of each composition of the Y5V powder prepared according to the method of Example 2-1 using BaCO ₃ are shown in Table 1 below.

The dielectric constant, dielectric loss, insulation resistance (IR), density, and sintering temperature of each composition of the Y5V powder prepared according to the method of Example 2-2 using BaTiO ₃ hydroxide are shown in Table 2 below.

The dielectric constant, dielectric loss, insulation resistance (IR), density, and sintering temperature of each composition of the Y5V powder prepared according to the method of Example 2-3 using the BCTZ prepared by the coprecipitation method are shown in Table 3 below.

In addition, data of capacitance (Cp), dielectric loss (DF), insulation resistance (IR), and dielectric breakdown voltage (BDV) of 20 chips manufactured by MLCC were compared with each other (see Table 4).

As described above, the MLCC sample prepared by using the Y5V dielectric powder of the present invention prevents cracks commonly occurring in chips using dielectric ceramic compositions prepared by mixing existing additives and sintering aids such as NiO and SiO ₂ . And it can be seen that there is an effect to improve the IR falling.

As described above, the present invention provides a dielectric composition by adding a predetermined amount of Mn _{1 + δ} TiO ₃ , BiVO ₄ and B-Silicate glass frit to the BCTZ base composition prepared by BaCO ₃ , BaTiO ₃ and coprecipitation method. Y5V MLCC can be manufactured to prevent cracks and improve IR falling, so it can be widely used in automobiles, computers, VCRs and mobile communication devices.

Claims (6)

(Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ + zY ₂ O ₃ , consisting of 0.01 ≦ x ≦ 0.08, 0.17 ≦ y ≦ 0.24, 0.001 ≦ z ≦ 0.004 and 1 ≦ m ≦ A dielectric composition for MLCC having excellent Y5V characteristics formed by adding a predetermined amount of two or more of Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05), BiVO ₄ and B-Silicate glass frit to a composition satisfying 1.04. The method of claim 1, The B-Silicate glass frit is SiO ₂ -MO (BaO-CaO-SrO) -B ₂ O ₃ -Al ₂ O ₃ -Li ₂ O-based glass frit, characterized in that the dielectric composition for MLCC. Mixing the raw materials consisting of BaCO ₃ , CaCO ₃ , TiO ₂ and ZrO ₂ , and then calcining them; Mixing Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05), BiVO ₄ , B-Silicate glass frit and Y ₂ O ₃ to the powder obtained by calcination, then grinding and drying; And Method for producing a dielectric composition for MLCC comprising the step of adding a small amount of the binder to the dry powder and molding, followed by sintering and reoxidation. Mixing the raw material consisting of BaTiO ₃ and BaCO ₃ , CaCO ₃ and ZrO ₂ prepared by the hydroxide method, and calcining it; Mixing Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05), BiVO ₄ , B-Silicate glass frit and Y ₂ O ₃ to the powder obtained by calcination, then grinding and drying; And Method for producing a dielectric composition for MLCC comprising the step of adding a small amount of the binder to the dry powder and molding, followed by sintering and reoxidation. Mn _{1 + δ} TiO ₃ (0 < _δ ≦ 0.05) was added to (Ba _1-x Ca _x ) _m (Ti _1-y Zr _y ) O ₃ prepared by co-precipitation, mixed, dried and calcined; Mixing BiVO ₄ , B-Silicate glass frit, and Y ₂ O ₃ to the powder obtained by calcination, then grinding and drying them; And Method for producing a dielectric composition for MLCC comprising the step of adding a small amount of the binder to the dry powder and molding, followed by sintering and reoxidation. The method according to claim 3 to 5, The sintering is sintered for 1 to 3 hours at an atmosphere condition of 1.5% H ₂ at a temperature of 1100 to 1300 ℃, the reoxidation is reoxidized for 2 to 4 hours at a condition of 20 ppm O ₂ partial pressure at a temperature of 900 to 1000 ℃. Method for producing a dielectric composition for MLCC, characterized in that.

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