Dielectric composition and multilayer ceramic condenser...

Details Dielectric composition and multilayer ceramic condenser... Dielectric composition and multilayer ceramic condenser...

2003-05-23

2004-05-11

Stein, Stephen (Department: 1775)

Stock material or miscellaneous articles

Composite

Of metal

C428S471000, C428S697000, C428S702000, C501S136000, C501S137000, C361S321400, C361S321500

Reexamination Certificate

active

06733897

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dielectric composition for a multilayer ceramic condenser and a multi-layer ceramic condenser using the same, and more particularly, to a multi-layer ceramic condenser made of dielectric composition to be sintered at low temperatures and have a high dielectric constant.
2. Description of the Related Art
A multi-layer ceramic condenser requires a high dielectric constant in response to demands of a minimized size and a high capacitance. Therefore, a new dielectric ceramic composition is needed to meet these demands.
The new dielectric ceramic composition must have a high dielectric constant to be used for making the multi-layer ceramic condenser to meet a temperature characteristic of Y5V, one of U.S. industrial standards, and the multi-layer ceramic condenser has been used in a circuit at which capacitance is high, and dependency of electrostatic capacitance on temperature change is not important.
One of conventional dielectric compositions used for the multi-layer ceramic condenser having the characteristic of Y5V is disclosed in a Japanese patent publication No. 2000-243652. The Japanese patent publication describes the dielectric composition with the following formula 1.
[(Ba
1−x
Ca
x
)(Ti
1−y
Zry)O
2+m
]
1−&agr;−&bgr;
+(⅓ Mn
3
O
4
)
&agr;
+(R
2
O
3
)
&bgr;
+aM+b(V
2
O
5
)+c(NiO)  Formula 1
wherein, 1.00≦m≦1.02, 0.001≦x≦0.05, 0.05≦y≦0.2, 0.001<&agr;≦0.015, 0.001≦&bgr;≦13<0.015, 0.01≦a≦0.5, 0≦b≦0.1, 0≦c≦0.2, M is BaO-AI2O3-SiO2-based glass, R is Y or Dy.
Thought the above described dielectric composition has a stable electrostatic capacitance and a high dielectric constant in the range of usage temperature of Y5V, a Ni terminal is disconnected from a condenser body and the size of the grain particles increase because the multi-layer ceramic condenser is sintered at a high temperature of about 1300° C. through 1350° C., As a result, the multi-layer ceramic condenser cannot have a desired reliability and a high dielectric constant.
SUMMERY OF THE INVENTION
In order to overcome the above and other problems, the present invention has an object to provide a dielectric compound for a multi-layer ceramic condenser having a low sintering temperature and a high dielectric constant.
It is another object of the present invention to provide a multi-layer ceramic condenser having an excellent dielectric breakdown voltage characteristic and a high capacitance with a low rate of disconnection of a terminal and a crack after sintering by using a dielectric compound having a high dielectric constant and being sintered at a relatively low temperature.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The above and other objects according to an embodiment of the present invention, may be achieved by providing a dielectric composition comprising: (Ba
x
Ca
1−x
)
m
(Ti
y
Zr
1−y
)O
3
, wherein 0.7≦x≦1, 0.75<y≦0.9, 0.998≦m≦1.006, as a base material; MnO
2
of less than about 0.8 weight %, Y
2
O
3
of less than 0.8 weight %, V
2
O
5
of 0~0.1 weight % base on a weight of the base material as a additive; and zLi
2
O-2(1−z)SiO
2
of less than about 1.0 weight %, wherein, 0.2≦z≦0.9, as a sintering aid. The weight % is a ratio relating to a weight of base material of the dielectric compound.
According to another aspect to the present invention, a multi-layer ceramic condenser has a ceramic layer made of the dielectric compound, and an internal terminal made of Ni.


REFERENCES:
patent: 5181157 (1993-01-01), Chazono et al.
patent: 5184277 (1993-02-01), Shizuno et al.
patent: 6458734 (2002-10-01), Sugimoto et al.
patent: 2000-243652 (2000-09-01), None

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