X7R dielectric composition
First Claim
1. A composition for use in forming a dielectric material for use in a multilayer ceramic chip capacitor comprising a sintered blend of:
- from about 99.8 to about 90.00 wt. % BaTiO3;
from about 0.067 to about 3.364 wt. % Mn3O4;
from about 0.040 to about 1.976 wt. % Y2O3;
from about 0.026 to about 1.320 wt. % Ho2O3;
from about 0.040 to about 1.993 wt. % CaCO3;
from about 0.011 to about 0.567 wt. % SiO2;
from about 0.008 to about 0.389 wt. % B2O3;
from about 0.004 to about 0.179 wt. % Al2O3;
from about 0.003 to about 0.164 wt. % MgO; and
from about 0.001 to about 0.047 wt. % CaO.
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Accused Products
Abstract
Multilayer ceramic chip capacitors which satisfy X7R requirements and which are compatible with reducing-atmosphere sintering conditions so that non-noble metals such as nickel, copper, and alloys thereof may be used for internal and external electrodes are made in accordance with the invention. The capacitors exhibit desirable dielectric properties (high capacitance, low dissipation factor, high insulation resistance), excellent performance on highly accelerated life testing, and very good resistance to dielectric breakdown. The dielectric layers preferably contain BaTiO3 as the major component and Mn3O4 Y2O3, Ho2O3, CaCO3, SiO2, B2O3, Al2O3, MgO, and CaO as minor constituents. They are batched in a proportion that there are preferably present 99.00 to 98.5 wt. % BaTiO3, 0.336 to 0.505 wt. % Mn3O4, 0.198 to 0.296 wt. % Y2O3, 0.132 to 0.198 wt. % Ho2O3, 0.199 to 0.299 wt. % CaCO3, 0.057 to 0.085 wt. % SiO2, 0.039 to 0.058 wt. % B2O3, 0.018 to 0.027 wt. % Al2O3, 0.016 to 0.025 wt. % MgO and 0.005 to 0.007 wt. % CaO. The B2O3, SiO2, MgO, Al2O3, and CaO are preferably present in the form of pre-reacted glass. The preferred form of the invention may be sintered in the temperature range 1,200 to 1,300° C. in a reducing atmosphere. Additionally, a re-oxidation procedure may be utilized during the sintering cycle to optimize the resistance of the ceramic to dielectric breakdown.
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Citations
16 Claims
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1. A composition for use in forming a dielectric material for use in a multilayer ceramic chip capacitor comprising a sintered blend of:
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from about 99.8 to about 90.00 wt. % BaTiO3;
from about 0.067 to about 3.364 wt. % Mn3O4;
from about 0.040 to about 1.976 wt. % Y2O3;
from about 0.026 to about 1.320 wt. % Ho2O3;
from about 0.040 to about 1.993 wt. % CaCO3;
from about 0.011 to about 0.567 wt. % SiO2;
from about 0.008 to about 0.389 wt. % B2O3;
from about 0.004 to about 0.179 wt. % Al2O3;
from about 0.003 to about 0.164 wt. % MgO; and
from about 0.001 to about 0.047 wt. % CaO. - View Dependent Claims (2)
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3. A multilayer ceramic chip capacitor comprising alternately stacked layers of a dielectric material and an internal electrode material comprising nickel, the dielectric material comprising a sintered blend of:
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from about 99.8 to about 90.00 wt. % BaTiO3;
from about 0.067 to about 3.364 wt. % Mn3O4;
from about 0.040 to about 1.976 wt. % Y2O3;
from about 0.026 to about 1.320 wt. % Ho2O3;
from about 0.040 to about 1.993 wt. % CaCO3;
from about 0.011 to about 0.567 wt. % SiO2;
from about 0.008 to about 0.389 wt. % B2O3;
from about 0.004 to about 0.179 wt. % Al2O3;
from about 0.003 to about 0.164 wt. % MgO; and
from about 0.001 to about 0.047 wt. % CaO. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
from about 99.8 to about 90.00 wt. % BaTiO3;
from about 0.067 to about 3.364 wt. % Mn3O4;
from about 0.040 to about 1.976 wt. % Y2O3;
from about 0.026 to about 1.320 wt. % Ho2O3;
from about 0.040 to about 1.993 wt. % CaCO3;
from about 0.011 to about 0.567 wt. % SiO2;
from about 0.008 to about 0.389 wt. % B2O3;
from about 0.004 to about 0.179 wt. % Al2O3;
from about 0.003 to about 0.164 wt. % MgO; and
from about 0.001 to about 0.047 wt. % CaO.
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11. A method of fabricating a multilayer ceramic chip capacitor having X7R characteristics comprising:
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providing a dielectric material comprising;
from about 99.8 to about 90.00 wt. % BaTiO3;
from about 0.067 to about 3.364 wt. % Mn3O4;
from about 0.040 to about 1.976 wt. % Y2O3;
from about 0.026 to about 1.320 wt. % Ho2O3;
from about 0.040 to about 1.993 wt. % CaCO3;
from about 0.011 to about 0.567 wt. % SiO2;
from about 0.008 to about 0.389 wt. % B2O3;
from about 0.004 to about 0.179 wt. % Al2O3;
from about 0.003 to about 0.164 wt. % MgO; and
from about 0.001 to about 0.047 wt. % CaO;
forming alternate stacked layers of said dielectric material with an internal electrode material comprising nickel;
applying heat and pressure to form a green chip; and
forming capacitors from said green chip. - View Dependent Claims (12, 13, 14, 15, 16)
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Specification
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- Resources
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Current AssigneeFerro Corporation (Vibrantz Technologies, Inc.)
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Original AssigneeFerro Corporation (Vibrantz Technologies, Inc.)
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InventorsPark, Hyun, Chu, Mike S. H., McCauley, Daniel E.
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Primary Examiner(s)GROUP, KARL E
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Application NumberUS10/440,051Publication NumberTime in Patent Office571 DaysField of Search501/137, 501/139, 361/321.4, 361/321.5US Class Current501/139CPC Class CodesB32B 2311/22 Nickel or cobaltC03C 3/091 containing aluminiumC03C 8/02 Frit compositions, i.e. in ...C03C 8/14 Glass frit mixtures having ...C04B 2235/3206 Magnesium oxides or oxide-f...C04B 2235/3208 Calcium oxide or oxide-form...C04B 2235/3217 Aluminum oxide or oxide for...C04B 2235/3224 Rare earth oxide or oxide f...C04B 2235/3225 Yttrium oxide or oxide-form...C04B 2235/3263 Mn3O4C04B 2235/3409 Boron oxide, borates, boric...C04B 2235/3418 Silicon oxide, silicic acid...C04B 2235/365 Borosilicate glassC04B 2235/5445 submicron sized, i.e. from ...C04B 2235/6025 Tape casting, e.g. with a d...C04B 2235/652 Reduction treatment C04B223...C04B 2235/6584 at an oxygen percentage bel...C04B 2235/663 Oxidative annealingC04B 2235/785 Submicron sized grains, i.e...C04B 2237/346 Titania or titanatesView All
