Dielectric Ceramic Composition for Multilayer Filters
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Solution Overview
Problem
Existing dielectric ceramic compositions for multilayer filters face challenges in achieving thin layers with reliable properties, as they often require high glass content, leading to large grain sizes, uneven crystalline textures, and reduced specific permittivity, while also being difficult to sinter at low temperatures without compromising insulation resistance.
Innovation Solution
A dielectric ceramic composition comprising barium titanate, strontium titanate, or calcium titanate as the main component, with a low-melting glass component (oxide of B) and optional Cu and Mn oxides, where the glass content is limited to 2-7 wt% and Cu and Mn are within specific ranges, allowing for low-temperature sintering and improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the content of glass component is increased to enable low-temperature sintering, then sintering temperature is reduced, but grain size becomes too large and crystalline texture becomes uneven
Solution Approach 1:
The patent changes the chemical composition parameters of the glass component by specifying precise ranges: B2O3 (1-3 wt%), SiO2 (70-78 wt%), and Al2O3 (1-5 wt%). This compositional optimization allows the glass to provide sufficient fluxing action for low-temperature sintering while controlling grain growth and maintaining uniform crystalline texture.
Solution Approach 2:
The patent creates a composite dielectric ceramic system combining SrTiO3-based main component with an optimized glass component containing B2O3, SiO2, and Al2O3. This composite material approach enables the glass to facilitate low-temperature sintering while the specific composition ratio prevents excessive grain growth and maintains texture uniformity.
2Volume of moving object
If the thickness of dielectric layer is reduced to downsize the multilayer filter, then device size and height are reduced, but reliability is not secured
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: glass component composition (B2O3, SiO2, Al2O3 ratios), sintering temperature (800-900°C), and holding time (1-3 hours). These parameter optimizations enable thin dielectric layers to achieve sufficient densification and reliability at low sintering temperatures, preventing defects even at reduced thicknesses.
Solution Approach 2:
The optimized glass component acts as a self-fluxing agent that facilitates sintering and densification of the thin dielectric layer at low temperatures without requiring additional external fluxes or complex processing steps. The glass composition automatically adjusts to promote grain boundary healing and defect elimination in thin layers.
3Ease of manufacture
If the content of glass component is increased to improve sinterability, then sintering becomes easier, but specific permittivity is reduced
Solution Approach 1:
The patent precisely controls the glass component content at 2-7 wt% and optimizes the ratios of B2O3, SiO2, and Al2O3 within the glass. This parameter optimization provides sufficient sinterability enhancement while limiting the dilution effect on the high-permittivity SrTiO3 main component, thereby maintaining high specific permittivity.
4Temperature
If the content of CuO is increased to improve sintering, then sintering temperature is reduced, but insulation resistance is reduced due to segregation
Solution Approach 1:
The patent limits CuO content to 0.1-3 wt% and combines it with an optimized glass component containing B2O3, SiO2, and Al2O3. This compositional control prevents excessive CuO segregation during sintering while maintaining low-temperature sinterability and preserving insulation resistance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition enables the production of thin, reliable dielectric layers with enhanced specific permittivity, loss Q value, and insulation resistance, while preventing plating solution penetration and structural defects, allowing for further downsizing of electronic devices.
Implementation Method 1
By including such a glass component in the above range, it is possible to sinter at a low temperature
Implementation Method 2
a low-melting glass having a glass softening point of 800° C. or lower
Data Source
AI summary
The present invention relates to a dielectric ceramic composition comprising a main component including at least one selected from barium titanate, strontium titanate and calcium titanate, and as a subcomponent, a glass component including an oxide of B, wherein a content of said glass component is 2 to 7 wt % with respect to 100 wt % of said main component. According to the present invention, there are provided a dielectric ceramic composition wherein a layer can be made thinner by relatively decreasing a content of the glass component, etc., as well as having good properties (specific permittivity, loss Q value and insulation resistance), and a complex electronic device such as a multilayer filter or a multilayer ceramic capacitor, which has a dielectric layer composed of the dielectric ceramic composition.