Multi-Layer Ceramic Capacitor Grain Growth Suppression
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Solution Overview
Problem
Multi-layer ceramic capacitors face a trade-off between reducing dielectric layer thickness for smaller size and maintaining sufficient capacitance, as finer grain sizes decrease the dielectric constant and increase the likelihood of lower electrical insulation properties due to fewer grain boundaries.
Innovation Solution
A multi-layer ceramic capacitor design with dielectric layers composed of a sintered compact containing specific ratios of ReO3, SiO2, MOx, ZrO2, and MgO, along with rare earth elements and metal elements, which suppresses grain growth to maintain sufficient grain boundaries and high dielectric constants, achieving high-density layering and improved reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dielectric layer thickness is reduced to achieve smaller capacitor size, then the capacitance decreases due to fewer grain boundaries and lower dielectric constant, but the capacitor size is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the dielectric material by adding specific amounts of MgO (0.01-3.0 mol%), ZrO2 (0.1-1.0 mol%), SiO2 (0.1-1.0 mol%), and other oxides to the BaTiO3 base material. These compositional parameter changes suppress grain growth during sintering, maintain adequate grain boundaries even in thin layers (1 μm or less), and preserve the dielectric constant while enabling high-density layering for smaller capacitor sizes
Solution Approach 2:
The patent creates a composite dielectric material system based on BaTiO3 with multiple additive oxides (MgO, ZrO2, SiO2, CaO, etc.). This composite material structure allows the dielectric layer to maintain sufficient grain boundaries and high dielectric constant despite reduced thickness, resolving the contradiction between miniaturization and electrical insulation reliability
2Productivity
If the grain size of dielectric is reduced to enable thinner dielectric layers, then the dielectric constant drops due to sizing effect, but the layer thickness can be reduced for high-density layering
Solution Approach 1:
The patent modifies the sintering behavior parameters by adding MgO and other oxide additives that suppress excessive grain growth. This parameter change allows the dielectric material to maintain fine grain sizes (enabling thin layers of 1 μm or less for high-density layering) while preventing the dielectric constant from dropping, thus resolving the contradiction between layering density and dielectric constant
Solution Approach 2:
The patent introduces MgO and other oxide additives as intermediary substances that mediate between the conflicting requirements of fine grain size (for thin layers) and high dielectric constant. These additives act as grain growth suppressors during sintering, allowing the material to achieve both fine microstructure and high dielectric properties simultaneously
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
This design ensures sufficient grain boundaries and high dielectric constants, enabling high-density layering while maintaining reliability and capacitance, even at smaller sizes.
Implementation Method 1
the dielectric layers are constituted by a sintered compact that contains a mol of ReO3/2, b mol of SiO2, c mol of MOx, d mol of ZrO2 and e mol of MgO... suppressing the grain growth when the dielectric grains constituting the dielectric layers are sintered
Data Source
AI summary
A multi-layer ceramic capacitor has a structure where its dielectric layers are constituted by a sintered compact that contains a mol of ReO3/2, b mol of SiO2, c mol of MOx, d mol of ZrO2, and e mol of MgO (where Re is a rare earth element, M is a metal element (except for Ba, Ti, Re, Si, Zr, Mg, and rare earth elements), and x is a valance) per 100 mol of BaTiO3, and a, b, c, d, and e mentioned above which indicate the mol numbers of respective constituents per 100 mol of BaTiO3 are 0.1≦a≦1.0, 0.1≦b≦1.5, 0.1≦c≦0.4, 0≦d≦1.0, and 0≦e≦0.03, respectively.