Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor

A technology of dielectric ceramics and multi-layer ceramics, applied in the field of dielectric ceramics and their preparation, can solve problems such as unstable reaction, reduction of capacitance-temperature characteristics and reliability of dielectric ceramics, reduction of thickness of dielectric ceramics layer, etc.

Active Publication Date: 2004-09-08
MURATA MFG CO LTD
View PDF6 Cites 14 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0015] Of course, although the dielectric ceramics disclosed in Japanese Unexamined Patent Application No. 5-9066 show excellent electrical insulation properties, when the thickness of these dielectric ceramic layers is reduced to, for example, 5 μm or less, especially to 3 μm or less , the reliability of the dielectric ceramics cannot always adequately meet the needs of the market
[0016] As in the case above, when the thickness of the dielectric ceramic layer is reduced to 2 μm or less, the capacitance-temperature characteristics and reliability of the dielectric ceramics disclosed in Japanese Unexamined Patent Applications 11-302071 and 2000-58377 are disadvantageously degraded. sex
[0017] In addition, in dielectric ceramics having a so-called core-shell structure disclosed in Japanese Unexamined Patent Applications Nos. 6-5460, 2001-220224, and 2001-230149, as the thickness of the dielectric ceramic layer decreases, its reliability also increases. disadvantageously reduced
In the dielectric ceramic disclosed in Japanese Unexamined Patent Application No. 9-270366, due to the addition of main components such as BaTiO 3 The additive component in is melted in the firing step, an unstable reaction occurs between the main component and the additive component, and specifically, as a result, when the thickness of the dielectric ceramic layer is reduced, due to the inability to Stable guarantees its reliability, problems can arise
[0018] The dielectric ceramic disclosed in Japanese Unexamined Patent Application No. 10-74666 is also problematic because its reliability decreases when the thickness of the dielectric ceramic layer is reduced, especially to 3 μm or less
In addition, since there are a large amount of volatile components such as lithium (Li) and boron (B), when the thickness of the dielectric ceramic layer is reduced, problems arise in the stability of electrical properties including reliability
[0019] When the thickness of the dielectric ceramic layers is reduced in order to meet the trend of miniaturization and higher capacitance of multilayer ceramic capacitors, its rated DC voltage is set to be applied to each of the dielectric ceramic layers as before. The electric field increases, with the result that its reliability is significantly reduced

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor
  • Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor
  • Dielectric ceramic and producing method thereof, and multilayer ceramic capacitor

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0075] In embodiment 1, as shown in table 1, use ABO 3 As main components, it includes Ba, Ca and Ti and has (Ba 0.93 Ca 0.07 )TiO 3 composition, and with BaCO 3 、TiO 2 and SiO 2mixture or Ba-Ti-Si-O crystal oxide as its additive component. By using these components, Examples 1-1 and 1-2 according to the present invention and Comparative Examples 1-1 and 1-2 other than the present invention were evaluated.

[0076] 1. Formation of powdered raw materials for dielectric ceramics.

Embodiment 1-1

[0078] First, for the raw materials of the main components, in order to form (Ba 0.93 Ca 0.07 )TiO 3 Composition, weigh BaCO by volume 3 , CaCO 3 and TiO 2 , which are then mixed together using a ball mill, followed by heat treatment at 1,050°C, thereby forming (Ba 0.93 Ca 0.07 )TiO 3 . The average diameter of the crystal grains was 0.3 μm.

[0079] In order to obtain the described additive components, weigh the BaCO 3 , CaCO 3 and TiO 2 , so that the molar ratio was 9:1:10, and then they were mixed together using a ball mill, followed by heat treatment at 1,000° C., thereby forming Ba—Ti—Si—O crystal oxide. The crystallinity of these oxides was confirmed using XRD. In addition, the average diameter of crystal grains was 0.15 μm.

[0080] Then, weigh by volume (Ba 0.93 Ca 0.07 )TiO 3 and Ba-Ti-Si-O crystal oxide so that the weight ratio is 98:2 as shown in Table 1, and then use a ball mill to mix them together, thereby forming the dielectric compound according ...

Embodiment 1-2

[0082] According to the same method described in the above embodiment 1-1, after obtaining (Ba 0.93 Ca 0.07 )TiO 3 and Ba-Ti-Si-O crystal oxide, weigh by weight (Ba 0.93 Ca 0.07 )TiO 3 and Ba-Ti-Si-O crystal oxide, so that the weight ratio is 95:5 as shown in Table 1, and then use a ball mill to mix them together, thus forming the dielectric material according to Example 1-2 Powdered raw materials for ceramics.

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
areaaaaaaaaaaa
diameteraaaaaaaaaa
diameteraaaaaaaaaa
Login to View More

Abstract

A dielectric ceramic formed by firing in a reducing atmosphere is provided. A multilayer ceramic capacitor formed by using the aforementioned dielectric ceramic has superior reliability even when the thicknesses of dielectric ceramic layers formed therefrom are reduced. The dielectric ceramic has crystal grains; and crystal boundaries and triple points, which are located between the crystal grains. The crystal grains contain perovskite compound grains composed of a perovskite compound represented by ABO3 (where A is Ba and Ca, or Ba, Ca and Sr; B is Ti, or Ti and a part thereof which is replaced with at least one of Zr and Hf) and crystal oxide grains composed of a crystal oxide containing at least Ba, Ti and Si, and about 80% or more of the number of the triple points each have a cross-sectional area of about 8 nm<2 >or less.

Description

technical field [0001] The present invention relates to dielectric ceramics and their preparation methods, and multilayer ceramic capacitors formed using said dielectric ceramics, and more particularly, the present invention relates to an improved method by which the formation of multilayer ceramics can be advantageously reduced The thickness of the capacitor's dielectric ceramic layer. Background technique [0002] In general, multilayer ceramic capacitors are formed by the following steps: [0003] First, ceramic green sheets containing powdery raw materials for dielectric ceramics are prepared, each ceramic green sheet having on its surface a conductive material to be formed in a desired pattern for internal electrodes. For dielectric ceramics, one can use e.g. BaTiO containing 3 material as its main component. [0004] Next, a plurality of ceramic green sheets including ceramic green sheets provided with the above-described conductive material are laminated on each ot...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/46C04B35/00H01B3/00H01B3/12H01G4/06H01G4/12H01G4/30H02H3/00
CPCH01G4/1227Y10T29/43H01G4/30H01G4/12
Inventor 中村友幸加藤成武藤和夫佐野晴信
Owner MURATA MFG CO LTD
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products