Ba-Ca Concentration Variation in MLCC Dielectric Layers
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Solution Overview
Problem
The challenge is to enhance the reliability of dielectric layers in ceramic electronic devices, particularly when the thickness of these layers is reduced, as they tend to degrade in insulation resistance due to reductive atmospheres during the firing process, which affects the insulation performance and temperature compensation characteristics.
Innovation Solution
A multilayer ceramic electronic device is designed with dielectric layers composed of (Ba, Sr, Ca)(Zr, Ti)O3, where the Ba and Ca concentrations vary within crystal grains, achieved by alternately stacking dielectric and internal electrode layers and adjusting the cooling conditions after firing to create a non-uniform concentration distribution, thereby enhancing insulation resistance and mechanical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of dielectric layers is reduced to downsize the device, then the device size is reduced, but the insulation resistance of the dielectric layers degrades
Solution Approach 1:
The patent applies local quality by creating non-uniform concentration distribution of Ba and Ca within the dielectric layer. Specifically, the concentration of Ba and Ca varies in at least one of the crystal grains, forming regions with different compositional characteristics. This local compositional variation creates barriers to ion diffusion pathways, thereby maintaining high insulation resistance even when the overall dielectric layer thickness is reduced for device downsizing.
2Volume of moving object
If the thickness of dielectric layers is reduced, then the device size is reduced, but the reliability relating to insulation resistance is degraded
Solution Approach 1:
The patent employs parameter changes by modifying the concentration parameters of Ba and Ca within the dielectric layer composition. By controlling the concentration distribution of these elements through specific cooling conditions after firing, the patent creates a compositional gradient that impedes ion diffusion. This parameter modification allows the dielectric layer to maintain insulation resistance at reduced thickness, enabling device downsizing without sacrificing reliability.
3Stability of the object's composition
If uniform concentration of Ba and Ca is maintained in crystal grains, then the dielectric properties are stable, but the insulation resistance degrades under high voltage
Solution Approach 1:
The patent resolves this contradiction by introducing local quality variations in the form of non-uniform Ba and Ca concentration distribution within crystal grains. While the overall composition remains stable for maintaining dielectric properties, the local compositional variations create barriers that block ion diffusion pathways. This prevents the formation of conductive paths under high voltage stress, thereby maintaining high insulation resistance while preserving dielectric stability.
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 variation in Ba and Ca concentrations within the dielectric layers acts as a barrier to ion diffusion, significantly improving insulation performance and reducing the likelihood of breakdown under high voltage, thus enhancing the reliability and mechanical stability of the ceramic electronic device.
Implementation Method 1
a cooling condition of the cooling is adjusted in the cooling so that a Ba concentration and a Ca concentration have variation in at least one of crystal grains in the dielectric layers
Data Source
AI summary
A ceramic electronic device includes a multilayer structure in which each of dielectric layers and each of internal electrode layers are alternately stacked, wherein a main component of the dielectric layers is (Ba, Sr, Ca)(Zr, Ti)O3, wherein a Ba concentration and a Ca concentration have variation in at least one of crystal grains in the dielectric layers.