KR20020012878A - A method for preparing ceramic powders for Y5V type multilayer ceramic Chip Capacitor - Google Patents

Abstract

PURPOSE: Provided is a powder preparation method for multilayer ceramic chip capacitors(MLCC) with excellent Y5V characteristics and reliability, which is characterized in that additives and/or sintering aids are added to powder synthesis process by solid state reaction unlike a conventional method adding additives to MLCC preparation process. CONSTITUTION: The multilayer ceramic capacitor powder, BaTiO3-based perovskite powder which has excellent F characteristics(Y5V), such as (Ba1-x-yCaxSry)m(Ti1-zZrz)O3, BCSTZ, and (Ba1-xCax)m(Ti1-zZrz)O3, BCTZ, is prepared by the following steps: mixing raw materials, BaCO3, CaCO3, SrCO3, TiO2 and ZrO2; primary calcining at 1100-1300deg.C; adding additives or/and sintering aids, where the additives are at least one compound(oxides, carbonates, nitrates, etc.) of element selected from La, Sm, Dy, Ho, Er, Yb, Mn, etc.; primary grinding; secondary calcining at 1100-1300deg.C; optionally adding additives or/and sintering aids; and secondary grinding to be 0.4-0.6micrometer of size.

Description

A method for preparing ceramic powders for Y5V type multilayer ceramic chip capacitor}

The present invention relates to a method for producing a powder for a multilayer chip ceramic capacitor (hereinafter referred to as MLCC), and more particularly, to a method for producing a composite perovskite powder for producing MLCC having excellent F characteristics (Y5V). It is about.

Recently, research has been actively conducted to use internal electrodes as base metals such as Ni in Pd in order to reduce manufacturing costs of multilayer ceramic capacitors. Since these base metals are easily oxidized when fired in an oxidizing atmosphere, the minor component must be kept reducing. Therefore, dielectrics having a reduction resistance composition have been developed to maintain insulation resistance even in reducing crisis firing. Most of the developed dielectrics for Y5V are (Ba _1-x Ca _x ) _m (Ti _1-z Zr _z ) O ₃ BaTiO ₃ -based composite perovskites such as (hereinafter referred to as BCTZ) and (Ba _1-xy Ca _x Sr _y ) _m (Ti _1-z Zr _z ) O ₃ (hereinafter referred to as BCSTZ).

The reduction resistant dielectric used in the production of the F characteristic MLCC is a multi-component composite perovskite, and in order to manufacture the MLCC, an additive and a sintering aid are generally mixed. In other words, during sintering, other additives are mixed with the composite perovskite of these multi-elements, and these additives are mixed with a known ceramic powder to impart reduction resistance to the final dielectric, increase insulation resistance, and increase sinterability. It also lowers the sintering temperature, controls the Curie temperature, and also controls the grain growth. Therefore, in the production of MLCC, an additive must be added, but in electronic ceramics whose properties depend on the additive component, uniform mixing of the additive will be essential.

A conventional process of preparing an MLCC by mixing an additive with a composite perovskite ceramic powder prepared by the solid phase synthesis method is shown in FIG. 1.

That is, as shown in Figure 1, BCSTZ powder is prepared by the solid phase synthesis method of mixing, calcining, and pulverizing the raw material, BCSTZ powder prepared in the subsequent batch process with additives, sintering aids, binders, plasticizers and solvents Are mixed. In addition, the slurry from the batch process is mixed through the aging process, and then produced through the molding, lamination, compression, and final heat treatment to manufacture the MLCC dielectric.

However, when mixing the additives, binder and solvent in the batch process described above, it is difficult to uniformly mix the elements due to the characteristics of the solid phase synthesis method, so that the secondary phase is locally present after the final heat treatment or some unreacted material remains. There is a problem that segregation, etc. due to non-uniform mixing of each additive, such as the production of MLCC having excellent dielectric properties is difficult.

Accordingly, the present invention is to solve the problems of the prior art, before the batch process, that is, composite perovskite capable of producing an MLCC having excellent dielectric properties by mixing the additive and the sintering aid in the step of synthesizing the powder by a solid phase synthesis method It is an object of the present invention to provide a method for preparing powder powder.

1 is a conventional synthetic process of Y5V composite perovskite powder and MLCC manufacturing process using the same

Figure 2 is a manufacturing process of the composite perovskite powder for Y5V according to the present invention

Figure 3 is an example of the manufacturing process chart of the composite perovskite powder of the present invention and MLCC manufacturing process chart

4 is a BCSTZ composite perovskite powder prepared by the conventional method,

Figure 4 (a) is a SEM tissue photograph after calcination,

4 (b) shows XRD,

Figure 4 (c) is a cross-sectional view of the MLCC prepared using this powder

5 is an example of the BCSTZ composite perovskite powder prepared by the present invention method,

Figure 5 (a) (b) (c) is a SEM micrograph after calcination,

5 (d) shows XRD,

5 (e) (f) (g) are cross-sectional views of MLCCs prepared using this powder.

Therefore, the present invention, after mixing the raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ), 1 Calcining the car; Mixing an additive and a sintering aid with the powder obtained by the first calcination, and then pulverizing the first; And secondly calcining the first milled powder and then second milling it. It relates to a composite perovskite powder manufacturing method having excellent Y5V characteristics, including.

In addition, the present invention, after the additive is mixed with a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) First calcining it; First grinding the ceramic powder obtained by the first calcination, and then calcining it secondly; And a second grinding step of mixing the sintering aid with the secondary calcined powder, and then pulverizing the secondary. The present invention relates to a composite perovskite powder manufacturing method having excellent Y5V characteristics.

In addition, the present invention, an additive and a sintering aid to a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) After mixing it is calcined; And it relates to a composite perovskite powder manufacturing method excellent in Y5V characteristics characterized in that it comprises a pulverized the calcined ceramic powder.

Hereinafter, the present invention will be described.

First, the present invention is characterized by mixing the additives and / or the sintering aid in the first and second grinding processes in producing BCSTZ powder by the solid phase synthesis method.

That is, as shown in Figures 2 (a), (b) and (c), first, barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and It is necessary to uniformly mix the raw material consisting of zirconium oxide (ZrO ₂ ).

At this time, the raw material used in the present invention may vary depending on the type of the final powder to be produced. That is, for BCTZ ((Ba _1-x Ca _x ) _m (Ti _1-z Zr _z ) O ₃ ) powders, barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) can be used as a raw material, and in the case of BTZ (Ba (Ti _1-z Zr _z ) O ₃ ) powder, barium carbonate (BaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) May be used as a raw material.

Next, the raw material mixed as described above is subjected to the first calcination, wherein the calcination temperature range is preferably limited to 1100 ~ 1300 ℃.

The first calcined ceramic powder is then first milled. Such grinding is performed in a mill such as a ball mill, and the grinding conditions may vary depending on the type of mill.

On the other hand, in the present invention, it is preferable to mix the additive and the sintering aid in the first grinding step.

The additive is preferably one or two or more compounds of La, Sm, Dy, Ho, Er, Yb, Mn, Y, Cr, Mg, Ni, Nd, Nb, V, W. In addition, the compound which is the additive is preferably in the form of oxides, halogen compounds, carbonate compounds, nitrides, sulfides.

As described above, the ceramic powder subjected to the first pulverization treatment is again subjected to the second calcination treatment, and the preferable temperature range is preferably limited to 1100 to 1300 ° C.

And the secondary calcined powder is a composite perovskite powder is produced by the secondary grinding treatment, wherein the secondary grinding is preferably performed so that the particle size of the powder is limited to 0.4 ~ 0.6㎛.

Meanwhile, in the present invention, the additive and the sintering aid may be mixed with the ceramic powder in the second grinding step instead of the first grinding step.

In addition, only the additives are mixed in the first grinding step, and the sintering aid may be mixed in the powder in the second grinding step.

In addition, the present invention is characterized in that, in the preparation of BCSTZ powder by the solid phase synthesis method, the additive is mixed with the raw material to the primary calcination treatment, and the sintering aid is mixed with the powder in the grinding step.

That is, the present invention, as shown in Figure 2 (d), (e), first, barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) And it is required to uniformly mix the raw material consisting of zirconium oxide (ZrO ₂ ).

At this time, as described above, the type of powder to be manufactured, that is, BCTZ ((Ba _1-x Ca _x ) _m (Ti _1-z Zr _z ) O ₃ ), BTZ (Ba (Ti _1-z Zr _z ) O ₃ ) The raw material may vary.

Meanwhile, in the present invention, it is preferable to mix the raw material with an additive. At this time, the additive is preferably one or two or more compounds of La, Sm, Dy, Ho, Er, Yb, Mn, Y, Cr, Mg, Ni, Nd, Nb, V, W. In addition, the compound which is the additive is preferably in the form of oxides, halogen compounds, carbonate compounds, nitrides, sulfides.

The raw material mixed with the additive is then first calcined, wherein the calcination temperature range is preferably limited to 1100 ~ 1300 ℃.

The first calcined ceramic powder is then subjected to a first pulverization treatment, in which the sintering aid is preferably mixed with the powder.

As described above, the ceramic powder subjected to the primary pulverization treatment is subjected to the second calcination treatment, and the preferred calcination temperature is 1100 to 1300 ° C.

And the secondary calcined powder is a composite perovskite powder is produced by the secondary grinding treatment, wherein the secondary grinding is preferably performed so that the particle size of the powder is limited to 0.4 ~ 0.6㎛.

Meanwhile, in the present invention, the sintering aid may be mixed with the ceramic powder in the second grinding step instead of the first grinding step.

In addition, the present invention is characterized in that in the preparation of BCSTZ powder by the solid phase synthesis method, both an additive and a sintering aid are mixed with a raw material to be calcined.

That is, the present invention, as shown in Figure 2 (f), barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) It is necessary to uniformly mix the raw materials made up.

In this case, as described above, at this time, as described above, the type of powder to be manufactured, that is, BCTZ ((Ba _1-x Ca _x ) _m (Ti _1-z Zr _z ) O ₃ ), BTZ (Ba (Ti (Ti _1-z Zr _z ) O ₃ ) The raw material may vary.

On the other hand, in the present invention, it is preferable to mix the additive and the sintering aid in the mixing step of the raw material. At this time, the additive is preferably one or two or more compounds of La, Sm, Dy, Ho, Er, Yb, Mn, Y, Cr, Mg, Ni, Nd, Nb, V, W. In addition, the compound which is the additive is preferably in the form of oxides, halogen compounds, carbonate compounds, nitrides, sulfides.

As described above, the raw material mixed with the additive and the sintering aid is calcined, wherein the calcination temperature is preferably limited to 1150 to 1200 ° C.

The calcined ceramic powder undergoes a grinding process to produce a composite perovskite powder, in which the grinding is preferably performed so that the particle size of the powder is limited to 0.4 to 0.6 μm.

Figure 3 is an illustration showing an example of the process of the present invention for producing an MLCC using the process as described above, in the subsequent batch process by mixing the additives and sintering aid in the process of synthesizing composite perovskite powder It can be seen that no mixing is required.

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

(Conventional example 1)

Barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) (Ba _0.843 Ca _0.07 Sr _0.09 ) (Ti _0.84 Zr _0.16 ) O After quantification to ₃ it was mixed with a ball-mill. As such, the mixture was calcined under normal conditions as shown in FIG. 1, and then ground to obtain BCSTZ composite perovskite powder.

The powder prepared as described above was placed in a ball jar again, and then subjected to a batch treatment by adding an additive, a sintering aid, a binder, a plasticizer, and a solvent. Table 1 shows.

On the other hand, Figure 4 (a) is a SEM micrograph after calcination of the BCSTZ composite perovskite powder prepared by a conventional process, Figure 4 (b) is an XRD, BCSTZ composite perovskite powder prepared by a conventional process, 4 (c) is a cross-sectional photograph of the prepared MLCC.

(Example 1)

Barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) (Ba _0.843 Ca _0.07 Sr _0.09 ) (Ti _0.84 Zr _0.16 ) O After quantification to ₃ it was mixed with a ball-mill for 20 hours. Thus, the mixture was dried and then first calcined at 1100 ° C.

The weight of the first calcined ceramic powder was accurately measured, and 0.3 wt% of the additive Y ₂ O ₃ + MnO ₂ and 0.2 wt% of the sintering aid SiO ₂ were mixed and then ground and mixed in a ball-mill for 20 hours. In addition, the ceramic powder mixed with the additive was dried and then calcined at 1150 ° C. for the second time, and then it was ground to a particle size of 0.4˜0.6 μm to prepare BCSTZ composite perovskite powder.

The powder prepared as described above was put back into a ball jar, and then binder, plasticizer and solvent were added and batched again for 20 hours. MLCC sample ⓐ was prepared at 1240 ° C. from the slurry obtained therefrom, and the dielectric properties and reliability thereof were measured. It is shown in Table 1 below.

As shown in Table 1 below, the MLCC sample ⓐ produced using the BCSTZ powder prepared by the present invention method is better than the conventional MLCC prepared by mixing the additive and the sintering aid in the subsequent batch process. It can be seen that the characteristics.

On the other hand, Figure 5 (a) is a SEM structure after calcination of the BCSTZ composite perovskite powder prepared by the present invention method, Figure 5 (d) XRD, Figure 5 (e) of the prepared MLCC sample ⓐ A cross-sectional photograph is shown.

Comparing FIG. 5 (a) with FIG. 4 (a), it can be seen that the powder produced by the present invention method is more uniform in particle size than the powder produced by the conventional method. Even when the MLCC is produced at a temperature, it can be seen that the MLCC prepared using the powder of the present invention has superior dielectric properties and reliability than the MLCC prepared by the conventional method.

That is, as can be seen from Figure 5 (e) and Figure 4 (c), when the MLCC is manufactured using the powder produced by the method of the present invention, the cross-section of the produced MLCC has a triple point compared to the conventional method Grain boundary parts such as and pores are significantly smaller, thus ensuring excellent dielectric properties.

This can also be confirmed from Figs. 5 (d) and 4 (b), which show that the XRD of the powder produced by the present invention method is sharper than the conventional method.

(Example 2)

Barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) (Ba _0.843 Ca _0.07 Sr _0.09 ) (Ti _0.84 Zr _0.16 ) O after the amount to be ₃ to 0.3% by weight of this additive was added to the Y ₂ O ₃ and MnO ₂ in a ball-mill and mixed for 20 hours.

As such, the mixture was first calcined at 1100 ° C. after drying, and then weighed again to add 0.2 wt% of SiO ₂ , a sintering aid, to grind and mix in a ball-mill for 20 hours. The ceramic powder was dried and then calcined at 1180 ° C. for the second time. Next, the ceramic powder was ground to have a particle size of 0.4˜0.6 μm to prepare BCSTZ composite perovskite powder.

MLCC sample ⓑ was prepared under the same conditions as in Example 1 using the powder prepared as described above, and the dielectric properties and reliability of the prepared MLCC sample ⓑ were measured and shown in Table 1 below.

As shown in Table 1 below, the present invention using the BCSTZ powder in which the additive and the sintering aid are mixed is more effective than the conventional method of mixing the additive and the sintering aid in the subsequent batch process. It can be seen that.

This is from Figure 5 (b) showing the SEM structure after calcination of the BCSTZ composite perovskite powder prepared by the present invention method, Figure 5 (f) showing a cross-sectional picture of the MLCC sample ⓑ prepared using the powder It can be explained well.

(Example 3)

Barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) (Ba _0.843 Ca _0.07 Sr _0.09 ) (Ti _0.84 Zr _0.16 ) O to then quantified so that the _third 0.3 wt% of the additive of Y ₂ O ₃ and MnO ₂ herein, and the ball-mill by adding a sintering aid of 0.2 wt% SiO ₂ was mixed for 20 hours.

The mixture was dried and calcined at 1180 ° C., and then pulverized in a ball-mill to have a particle size of 0.4˜0.6 μm to prepare BCSTZ composite perovskite powder.

MLCC sample ⓒ was prepared under the same conditions as in Example 1 using the powder prepared as described above, and the dielectric properties and reliability of the prepared MLCC sample ⓒ were measured and shown in Table 1 below.

As shown in Table 1 below, the present invention using the BCSTZ powder in which the additive and the sintering aid are mixed is more effective than the conventional method of mixing the additive and the sintering aid in the subsequent batch process. It can be seen that.

Characteristic of the present invention, which is distinguished from the conventional method, is a cross-sectional photograph of the MLCC sample © prepared using the powder of FIG. 5 (c) showing the SEM structure after calcination of the BCSTZ composite perovskite powder prepared by the present method. This can be well explained from Fig. 5 (g).

Conventional Law Invention method Sample ⓐ Sample ⓑ Sample ⓒ Examination Failure 0 0 0 One c / n 40/40 11/40 15/40 27/39 Early failure 6 One One One Exam time 51.0 51.0 51.0 51.0 Total test time 282.7 1882.7 1761.0 1604.7 AF 2.85E + 06 2.85E + 06 2.85E +06 2.85E + 06 Failure rate (λ, Fit) 45.9 2.0 3.0 5.9

As described above, the present invention provides a powder by mixing an additive and / or a sintering aid in the process of synthesizing the composite perovskite powder by the solid phase method, thereby eliminating the need to mix additives and the like in a subsequent MLCC manufacturing process. It is useful for the production of MLCCs having dielectric properties and reliability.

Claims (24)

Mixing a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ), and then calcining the first material; Mixing an additive and a sintering aid with the powder obtained by the first calcination, and then pulverizing the first; And After the secondary calcination of the first milled powder, the second milling step; Y5V characteristics excellent composite perovskite powder manufacturing method comprising a; The method of claim 1, wherein the primary calcination temperature and the secondary calcination temperature is a composite perovskite powder manufacturing method characterized in that 1100 ~ 1300 ℃ The method of claim 1, wherein the secondary grinding is a composite perovskite powder production method characterized in that the particle size of the powder is performed 0.4 ~ 0.6㎛ The method of claim 1, wherein the additive is one or two or more compounds of La, Sm, Dy, Ho, Er, Yb, Mn, Y, Cr, Mg, Ni, Nd, Nb, V, W Manufacturing method of composite perovskite powder The method of claim 4, wherein the additive is an oxide, a halogen compound, a carbonate compound, a nitride, or a sulfide-type compound. The composite ferep of claim 1, wherein a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) is used instead of the raw material. How to make sky powder The method of claim 1, wherein the raw material is made of barium carbonate (BaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) instead of the raw material. The method of claim 1 or 2, wherein the additive and the sintering aid are mixed with the powder in the secondary grinding step. The method of claim 1 or 2, wherein the additive is mixed in the first milling step, and the sintering aid is mixed in the second milling step. After the additive is mixed with a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ), step; First grinding the ceramic powder obtained by the first calcination, and then calcining it secondly; And After mixing the sintering aid in the secondary calcined powder, the secondary grinding step; Y5V characteristics excellent composite perovskite powder manufacturing method comprising a The method of claim 10, wherein the primary calcination temperature and secondary calcination temperature is 1100 ~ 1300 ℃ characterized in that the composite perovskite powder manufacturing method The method of claim 10, wherein the secondary grinding is performed so that the particle size of the powder is 0.4 to 0.6 μm. The method of claim 10, wherein the additive is one or two or more compounds of La, Sm, Dy, Ho, Er, Yb, Mn, Y, Cr, Mg, Ni, Nd, Nb, V, W Manufacturing method of composite perovskite powder The method of claim 13, wherein the additive is an oxide, a halogen compound, a carbonate compound, a nitride, or a sulfide-type compound. The composite ferep of claim 10, wherein a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) is used instead of the raw material. How to make sky powder The method of claim 10, wherein the raw material is made of barium carbonate (BaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) instead of the raw material. 12. The method for producing a composite perovskite powder according to claim 10 or 11, wherein the sintering aid is mixed in the first grinding step. After mixing the additive and sintering aid to the raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), strontium carbonate (SrCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) ; And pulverizing the calcined ceramic powder; a composite perovskite powder manufacturing method having excellent Y5V characteristics, including 19. The method of claim 18, wherein the calcination temperature is 1150 ~ 1200 ℃. The method of claim 18, wherein the pulverization is performed so that the particle size of the powder is 0.4 ~ 0.6㎛. The method according to claim 18, wherein the additive is one or two or more compounds of La, Sm, Dy, Ho, Er, Yb, Mn, Y, Cr, Mg, Ni, Nd, Nb, V, W Manufacturing method of composite perovskite powder 22. The method of claim 21, wherein the additive is an oxide, a halogen compound, a carbonate compound, a nitride, or a sulfide compound. 19. The composite ferep of claim 18, wherein a raw material consisting of barium carbonate (BaCO ₃ ), calcium carbonate (CaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) is used instead of the raw material. How to make sky powder 19. The method of claim 18, wherein the raw material is formed of barium carbonate (BaCO ₃ ), titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) instead of the raw material.