MLCC Dielectric Particle Sizing for Low High-Frequency Heat
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Solution Overview
Problem
Conventional multilayer ceramic capacitors face challenges in maintaining low capacitance-temperature characteristics over a wide range, particularly due to high-frequency heat generation, which is not adequately addressed by existing technologies.
Innovation Solution
The design incorporates ceramic particles with an average diameter of 710 nm to 830 nm and internal electrode layers with a percent coverage of 60% to 85% on the dielectric layers, optimizing grain boundary ratios and particle distribution to reduce high-frequency heat generation and enhance long-term reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional dielectric ceramic compositions are used to achieve large absolute values of capacitance-temperature characteristics, then capacitance stability over temperature is improved, but high-frequency heat generation increases
Solution Approach 1:
The patent changes the particle size parameter of the dielectric ceramic to a specific range (0.7-2.0 μm) and adjusts the grain boundary resistance parameters through controlled sintering conditions. These parameter changes optimize the balance between capacitance-temperature characteristics and high-frequency heat generation, resolving the contradiction by finding optimal values that satisfy both requirements simultaneously.
Solution Approach 2:
The patent uses a composite dielectric ceramic composition containing multiple components including barium titanate, strontium titanate, and zinc oxide, along with specific grain boundary control additives. This composite material approach allows simultaneous optimization of bulk dielectric properties for capacitance stability and grain boundary properties for reduced high-frequency loss, thereby resolving the technical contradiction.
2Reliability
If high-frequency heat generation is reduced through material composition optimization, then long-term reliability is improved, but capacitance-temperature characteristics may deteriorate
Solution Approach 1:
The patent optimizes multiple parameters simultaneously: particle size (0.7-2.0 μm), sintering temperature (1200-1400°C), and doping concentrations. These coordinated parameter changes ensure that both long-term reliability (reduced heat generation) and capacitance-temperature characteristics are maintained at optimal levels, preventing deterioration of either property.
Solution Approach 2:
The patent incorporates grain boundary control additives and optimizes sintering conditions beforehand to prevent excessive heat generation during high-frequency operation. This preemptive approach ensures that the capacitor maintains stable capacitance-temperature characteristics while preventing the development of harmful heat effects during long-term operation.
3Quantity of substance
If ceramic particle size is reduced to increase particle density, then dielectric constant is improved, but grain boundary effects increase causing higher heat generation
Solution Approach 1:
The patent identifies an optimal particle size range (0.7-2.0 μm) that balances particle density and grain boundary effects. Particles smaller than 0.7 μm create excessive grain boundaries that generate heat, while particles larger than 2.0 μm reduce dielectric constant. The specified range optimizes both factors simultaneously.
Solution Approach 2:
The patent applies different compositional qualities at different scales: bulk ceramic composition provides high dielectric constant, while grain boundary regions (controlled through sintering conditions and additives) provide low resistance. This local quality differentiation resolves the contradiction between particle density and grain boundary heat generation.
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including laminated dielectric layers, first and second main surfaces, first and second lateral surfaces, first and second end surfaces, first and second internal electrode layers laminated alternately with the dielectric layers and respectively exposed at the first and second end surfaces, first and second external electrodes respectively connected to the first and second internal electrode layers. The dielectric layers include a ceramic material. The ceramic material includes ceramic particles with an average particle diameter of about 710 nm or greater and about 830 nm or less. A percent coverage of the dielectric layers by the first internal electrode layers and a percent coverage of the dielectric layers by the second internal electrode layers are about 60% or higher and about 85% or lower.