TWI397090B - A ceramic powder composition, a ceramic material and a laminated ceramic capacitor produced - Google Patents

Description

Ceramic powder composition, ceramic material and laminated ceramic capacitor made thereof

The present invention relates to a ceramic powder composition, a ceramic material and a laminated ceramic capacitor thereof, and particularly relates to a ceramic powder composition, a ceramic material and a ceramic material which can meet the X8R temperature range. Laminated ceramic capacitors.

In recent years, as the development trend of electronic components is toward miniaturization, wafer formation, multi-function, and high capacity, various integrated technologies have begun to receive attention, and capacitors are no exception, except for thinner and multi-layered designs. In addition to the trend of avoidance, the design requirements of dielectric materials with high capacitance values and small grain structures are becoming more and more rigorous, so the development of ceramic capacitors is also being developed in the direction of maximizing the function in the smallest volume.

The application of commercial ceramic capacitors is mainly Class II, which can be divided into Y5V, X5R, X7R and other specifications. The X7R specification is more rigorous. The X7R basically requires the specification to be in the temperature range from -55 °C to 125 °C. (Based on 25 ° C), its relative capacitance change is less than 15%. At present, the material conforming to the X7R specification, one of which is a barium titanate (BaTiO ₃ ) system, is based on barium titanate, and additionally adds some trace modifiers such as Ta ₂ O ₅ and Nb ₂ O ₅ . Nd ₂ O ₅ , CoO, NiO, CeO _{2 ,} MnCO _{3 ,} etc., to modify the dielectric properties of the sintered body.

However, ceramic capacitors conforming to the X7R specification are only suitable for environments with temperature ranges from -55 ° C to 125 ° C, if the system is higher than the operating environment At 125 ° C, such as: petroleum exploration, automotive or aerospace electronic equipment applications, X7R ceramic capacitors have certain concerns in high temperature environments, and have relative use restrictions.

In view of this, the problem to be solved by the present invention is to overcome the problem of the X7R use limitation, and to provide a temperature range that can meet the X8R (ie, the relative capacitance change rate is less than 15% between -55 ° C and 150 ° C). Ceramic powder composition, ceramic material and laminated ceramic capacitor made thereof.

In order to solve the above problems, the technical means proposed by the present invention is that the present invention provides a dielectric ceramic powder composition comprising a main component and a vitreous component, the main component being 100BaTiO ₃ +αAO+βMnO+γB ₂ O ₅ +δRe ₂ O ₃ composition, wherein α, β, γ and δ are molar ratio constants, 0.8≦α≦2.5, 0≦β≦0.4, 0.06≦γ≦0.6, 0.3≦δ≦5, and element A is selected from magnesium a group consisting of (Mg), calcium (Ca), strontium (Sr), and barium (Ba), and element B is selected from the group consisting of vanadium (V), niobium (Nb), and tantalum (Ta). Re is selected from the group consisting of yttrium (Y), strontium (Tb), dysprosium (Dy), strontium (Ho), strontium (Er), strontium (Tm), and strontium (Yb), a vitreous component, It is composed of oxide SiO ₂ -TiO ₂ -XO. The chemical formula can also be expressed as X(Si _1-θ Ti _θ )O ₃ , where 0≦θ≦0.4, and X is selected from barium (Ba) calcium (Ca). And a group consisting of strontium (Sr) magnesium (Mg), zinc (Zn), and manganese (Mn), and the molar ratio of the vitreous component to the BaTiO ₃ is between 0 and 0.02.

In the above embodiment of the invention, the ceramic powder composition further comprises a dopant zirconium oxide (ZrO ₂ ), and the addition amount of the dopant zirconia and the Mohr proportional constant value of the BaTiO ₃ is between 0 and 0.025. .

The present invention further provides a ceramic material which is sintered from the above ceramic powder composition and has a sintering temperature of 1150 to 1250 °C.

The present invention further provides a multilayer ceramic capacitor comprising: a ceramic dielectric sintered from the ceramic powder group; a plurality of internal electrodes extending substantially parallel to the ceramic dielectric; and at least one external The electrode is exposed to the ceramic dielectric and electrically connected to the internal electrodes.

In the above embodiment of the invention, the volume change of the multilayer ceramic capacitor conforms to the X8R temperature range, that is, the temperature range is between -55 ° C and 150 ° C, and the relative volume change is less than 15%.

The effect obtained by the present invention is that the present invention provides a ceramic powder composition and ceramic material which can meet the X8R temperature range through the mutual matching of the main component of a barium titanate system and a vitreous component. The laminated ceramic capacitor made by the same can overcome the problem of the limitation of the use of the X7R ceramic capacitor at high temperatures. In addition, the addition of vitreous components to the barium titanate system can reduce the sintering temperature during the manufacturing process, reduce the stress caused by different materials, and improve the process stability.

Hereinafter, the ceramic powder composition according to the preferred embodiment of the present invention will be described with reference to the accompanying drawings. For the sake of understanding, the same elements in the following embodiments are denoted by the same reference numerals.

The ceramic powder composition of the present invention contains barium titanate in a specific ratio The main ingredient and a vitreous component are the main components.

The main component of the barium titanate system is composed of BaTiO ₃ , AO, MnO, B ₂ O ₅ and Re ₂ O ₃ , and the element A is selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr) and strontium ( The group consisting of Ba) is selected from the group consisting of vanadium (V), niobium (Nb) and tantalum (Ta), and the element Re is selected from the group consisting of yttrium (Y), yttrium (Tb), yttrium ( A group consisting of Dy), 鈥 (Ho), 铒 (Er), 銩 (Tm), and 镱 (Yb).

The vitreous component is composed of oxide SiO ₂ -TiO ₂ -XO (XST for short), and X is selected from barium (Ba) calcium (Ca), strontium (Sr) magnesium (Mg), zinc (Zn) and manganese. (Mn) is a group consisting of AO, MnO, B ₂ O ₅ and Re ₂ O ₃ contained in the main component of the barium titanate system in order to obtain a ceramic powder composition which can meet the X8R temperature range, wherein AO and The Mohr proportional constant value of the BaTiO ₃ is between 0.008 and 0.025, the Mohr proportional constant value of the MnO and the BaTiO ₃ is between 0 and 0.004, and the Mohr proportional constant value of the B ₂ O ₅ and the BaTiO _{3 is obtained} . It is between 0.0006 and 0.006, and the Mohr proportional constant value of Re ₂ O ₃ and the BaTiO ₃ is between 0.003 and 0.05.

The glassy component XST can also be expressed as X(Si _1-θ Ti _θ )O ₃ , where 0 ≦ θ ≦ 0.4, wherein the glassy component and the Mohr ratio constant value of the BaTiO ₃ are between 0 and 0.02. between.

In addition, the ceramic powder composition further comprises a dopant zirconium oxide (ZrO ₂ ), and the additive zirconia addition amount and the MoTiO ratio constant value of the BaTiO ₃ are between 0 and 0.02.

The ceramic powder composition of the present invention is mainly applicable to a laminated ceramic capacitor element. Please refer to FIG. 1 , which is a ceramic powder composition of the present invention. A multilayer ceramic capacitor with a structural cross-sectional view of a laminated ceramic capacitor. The multilayer ceramic capacitor 1 includes a capacitor ceramic body 110 and an external electrode 120. The capacitor ceramic body 110 includes a plurality of dielectric ceramic layers 112 and a plurality of internal electrodes 111 formed along the surface of the dielectric ceramic layer, and external electrodes. The 120 series is formed outside the capacitor ceramic body 110 and electrically connected to a portion of the internal electrode 111.

In this application, the above-mentioned dielectric ceramic layer 112 composed of a ceramic material is sintered from the ceramic powder composition of the present invention, and the sintering temperature is 1150 to 1250 °C. The ceramic powder composition of the present invention is sintered to form the dielectric ceramic layer 112, and the capacitance change of the laminated ceramic capacitor is in accordance with the X8R temperature range, that is, in the temperature range of -55 ° C to 150 ° C. The relative volume change is less than 15%.

Hereinafter, the present invention will be described by way of Experimental Example 1 to Experimental Example 8, but the present invention is not limited to the following experimental examples.

Experimental example 1

Using the addition ratios as shown in Table 1, the results of adding different proportions of the glassy addition amount were observed. After the respective compositions were uniformly mixed to form a slurry, the density of the sintered body was measured after sintering, and compared with its theoretical density. The results are shown in Table 2.

With the increase of the amount of vitreous added, the density of ζ≧0.47 is ≧5.74g/cm ³ , based on the density of BaTiO ₃ (densitization = actual density / theoretical density of BaTiO ₃ 6.02 g/cm ³ ), The density can be up to 96%. When ζ≧1.25, it can be found in the density curve that its density is ≧5.85g/cm ³ , based on the density of BaTiO ₃ (density = actual density / theoretical density of BaTiO ₃ 6.02 g/cm ³ ), dense The degree is 97% and meets the X8R specification.

Experimental example 2

Using the addition ratio as shown in Table 3, the results of changing the amount of addition of MgO and XST were observed. After the respective compositions were uniformly mixed to form a slurry as described above, the dielectric properties of the sintered body were measured after sintering, and the results are shown in Table 4.

Experimental example 3

The results of adding different ratios of MnO were observed using the addition ratios as shown in Table 5. After the respective compositions were uniformly mixed to form a slurry as described above, the dielectric properties of the sintered body were measured after sintering, and the results are shown in Table 6.

Experimental example 4

Using the addition ratios as shown in Table 7, the results of adding different ratios of V ₂ O ₅ added were observed. After the respective compositions were uniformly mixed to form a slurry as described above, the dielectric properties of the sintered body were measured after sintering, and the results are shown in Table 8.

Experimental example 5

Using the addition ratios as shown in Table 9, the results of adding different ratios of Y ₂ O ₃ addition were observed. After the respective compositions were uniformly mixed into a slurry as described above, the dielectric properties of the sintered body were measured after sintering, and the results are shown in Table 10.

Experimental example 6

Using the addition ratios as shown in Table 11, the results of adding different ratios of ZrO ₂ addition were observed. After the respective compositions were uniformly mixed to form a slurry as described above, the dielectric properties of the sintered body were measured after sintering, and the results are shown in Table 12.

Experimental example 7

In addition, for the above-mentioned A4 and A5 groups, sintering is carried out under three different sintering temperatures (1150 ° C, 1200 ° C, 1250 ° C). It was found that the sintering temperature can be effectively reduced to 1150 ° C, which still meets the X8R specification.

Experimental Example 8

A layer of ceramic capacitors was fabricated using A4 composition, and 1.2% of XST was added to be sintered at 1250 ° C. The relationship between the capacitance change rate of the multilayer ceramic capacitor and the temperature is shown in Fig. 2. The multilayer ceramic capacitor also conforms to the X8R specification.

It can be seen from the experimental results that the present invention provides a ceramic powder composition, a ceramic material and a ceramic material which can meet the X8R temperature range by the mutual composition of the main component of the barium titanate system and a glassy component. In addition to overcoming the limitations of X7R ceramic capacitors at high temperatures, laminated ceramic capacitors can also reduce the sintering temperature during the process and reduce the stress caused by different materials due to the addition of vitreous components to the barium titanate system. It has the effect of improving process stability.

In summary, the present invention is only described as a preferred embodiment or embodiment of the technical means for solving the problem, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or the scope of the invention are covered by the scope of the invention.

1‧‧‧Multilayer ceramic capacitors

110‧‧‧Capacitor ceramic body

111‧‧‧Internal electrodes

112‧‧‧Dielectric ceramic layer

120‧‧‧External electrode

1 is a structural cross-sectional view of a laminated ceramic substrate structure; and FIG. 2 is a graph showing a relationship between a capacitance change rate and a temperature of a multilayer ceramic capacitor when a 1.2% XST is added at 1250 ° C.

1‧‧‧Multilayer ceramic capacitors

110‧‧‧Capacitor ceramic body

111‧‧‧Internal electrodes

112‧‧‧Dielectric ceramic layer

120‧‧‧External electrode

Claims (8)

A dielectric ceramic powder composition comprising: a main component consisting of 100BaTiO ₃ +αAO+βMnO+γB ₂ O ₅ +δRe ₂ O ₃ , wherein α, β, γ and δ are molar ratio constants, 0.8≦α≦2.5 , 0.001 ≦ β ≦ 0.4, 0.06 ≦ γ ≦ 0.6, 0.3 ≦ δ ≦ 5, and element A is selected from the group consisting of magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). Element B is selected from the group consisting of vanadium (V), niobium (Nb), and tantalum (Ta), and element Re is selected from the group consisting of yttrium (Y), yttrium (Tb), dysprosium (Dy), and yttrium (Ho). a group consisting of erbium (Er), yttrium (Tm), and yttrium (Yb); and a vitreous component consisting of oxide SiO ₂ -TiO ₂ -XO, wherein X is selected from strontium (Ba) calcium a group consisting of (Ca), strontium (Sr) magnesium (Mg), zinc (Zn), and manganese (Mn), and the molar ratio of the vitreous component to the BaTiO ₃ is between 0.001 and 0.02. . The ceramic powder composition according to claim 1, wherein the vitreous component is also represented by X(Si _1-θ Ti _θ )O ₃ , which is 0 ≦ θ ≦ 0.4. The ceramic powder composition according to claim 1, further comprising a dopant zirconium oxide (ZrO ₂ ). The ceramic powder composition according to claim 3, wherein the additive zirconia addition amount and the MoTiO ratio constant value of the BaTiO ₃ are between 0.001 and 0.02. A ceramic material obtained by sintering a ceramic powder composition of the first application of the patent scope. The ceramic material according to claim 5, wherein the ceramic material has a sintering temperature of 1150 to 1250 °C. A multilayer ceramic capacitor comprising: a ceramic dielectric sintered from a ceramic powder composition as in claim 1; a plurality of internal electrodes extending substantially parallel to the ceramic dielectric; At least one external electrode is exposed to the ceramic dielectric and electrically connected to the internal electrodes. The multilayer ceramic capacitor according to claim 7, wherein the capacitance change of the multilayer ceramic capacitor conforms to the X8R temperature range, that is, the temperature range is between -55 ° C and 150 ° C, and the relative volume change thereof is Less than 15%.