Multilayer Ceramic Dielectric Sn Profile for Insulation and Capacitance
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Solution Overview
Problem
Multilayer ceramic electronic devices face challenges in maintaining high insulation resistance and electrostatic capacity due to the ferroelectric characteristics of the dielectric layer, which can lead to oxygen defects and reduced device lifetime.
Innovation Solution
The ceramic electronic device employs a multilayer structure with internal electrode layers and dielectric layers, where Sn is solid-solved in the ceramic dielectric layers to suppress the solid-solution of the internal electrode metal, thereby improving insulation characteristics and extending device lifetime. The Sn concentration is gradientially distributed, with lower concentrations near the outer ends and higher concentrations in the center, to balance sintering promotion and electrostatic capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Sn is added to the dielectric layer to suppress oxygen defects and improve insulation resistance, then the insulation characteristics are improved, but the sintering is promoted and electrostatic capacity is reduced
Solution Approach 1:
The patent applies local quality by creating a gradient distribution of Sn concentration within the dielectric layer. The Sn concentration is higher near the internal electrode layers where oxygen defects are most problematic, and lower in the center region where electrostatic capacity is critical. This spatially varying composition allows the dielectric layer to simultaneously achieve high insulation resistance at the interfaces while maintaining high electrostatic capacity in the bulk.
Solution Approach 2:
The patent employs parameter changes by systematically varying the Sn concentration as a continuous parameter throughout the dielectric layer thickness. By controlling the Sn concentration gradient (higher at boundaries, lower in center), the patent optimizes the balance between suppressing oxygen defects (improving insulation) and maintaining ferroelectric properties (preserving electrostatic capacity).
2Duration of action of stationary object
If Sn concentration is increased to improve insulation characteristics, then device lifetime is extended, but sintering is promoted causing disarrangement of multilayer structure
Solution Approach 1:
The patent uses local quality by concentrating higher Sn content in specific regions (near internal electrodes) where it provides the most benefit for suppressing oxygen defects and extending lifetime. The lower Sn content in the center region prevents excessive sintering that would cause multilayer disarrangement, thus maintaining structural stability while still achieving lifetime extension in the critical interface regions.
3Reliability
If Sn is solid-solved in the dielectric layer to suppress internal electrode metal solid-solution, then insulation characteristic is improved, but manufacturing complexity increases due to gradient concentration control
Solution Approach 1:
The patent manages manufacturing complexity by defining a systematic parameter change - a Sn concentration gradient that follows a specific distribution pattern (higher at boundaries, lower in center). This provides a clear manufacturing target that can be achieved through controlled co-firing processes, where the gradient emerges from the thermal diffusion characteristics during the sintering cycle, rather than requiring complex multi-step doping procedures.
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 approach effectively enhances the insulation characteristics of the dielectric layers, increases the lifetime of the ceramic electronic devices, and maintains high electrostatic capacity by controlling the Sn concentration gradient.
Implementation Method 1
Sn is solid-solved in the main component ceramic of the dielectric layer
Implementation Method 2
firing the multilayer structure
Data Source
AI summary
A ceramic electronic device includes a multilayer chip in which internal electrode layers are alternately stacked with dielectric layers, respectively, and are exposed alternately at a first surface and a second surface of the multilayer chip, wherein, in a capacity section in which the internal electrode layers exposed at the first and second surface overlap each other as viewed in the stacking direction, the dielectric layers are at least three dielectric layers, each dielectric layer including Sn, wherein a dielectric layer having a smaller Sn concentration is closer to an outermost end in the stacking direction than is a dielectric layer having a larger Sn concentration which is located at a center area in the stacking direction, in a relationship of at least two of the at least three dielectric layers in the capacity section.