Multilayer Ceramic Capacitor Electrode Length Uniformity
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Solution Overview
Problem
Multilayer ceramic capacitors face reliability issues due to length variations and thickness nonuniformity caused by cumulative height differences during the compressing process, leading to electric field concentration and degradation of shorting and IR characteristics.
Innovation Solution
A multilayer ceramic capacitor design with a length difference rate of inner electrodes of 7% or less, achieved by controlling the thickness of dielectric layers and applying a flexible member during compression, and modifying the organic composition of the passivation layer to manage recess amounts and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of laminations is increased to achieve higher capacitance, then the capacitance increases, but the cumulative height difference increases causing length variation and thickness nonuniformity
Solution Approach 1:
The patent applies parameter changes by modifying the organic material content in the dielectric layer to optimize compressibility. Specifically, the organic material content is controlled within 5-20 wt% of the total dielectric layer composition, which allows the cumulative height difference to be reduced to 10 μm or less even when 500+ layers are laminated. This parameter optimization enables high capacitance while maintaining length uniformity of inner electrodes within ±5 μm.
Solution Approach 2:
The patent applies local quality by creating a gradient in organic material distribution within the dielectric layer. The organic material content varies from 5-20 wt% depending on the position and function of the dielectric layer, allowing different regions to have optimized properties for compression behavior. This local optimization ensures uniform pressure distribution during compression while maintaining high overall capacitance.
2Quantity of substance
If the dielectric layer thickness is reduced to increase the number of layers, then the capacitance increases, but the recess amount during compression increases causing density distribution and elongation variation
Solution Approach 1:
The patent applies parameter changes by optimizing the organic material content parameter in the dielectric layer to 5-20 wt%. This parameter optimization controls the recess amount during compression to be 10 μm or less, which maintains density distribution within ±0.05 g/cm³. This enables the use of thin dielectric layers (0.5-2.0 μm) to achieve high capacitance while maintaining thickness uniformity.
3Ease of manufacture
If the cumulative height difference is not controlled, then the manufacturing process is simpler, but electric field concentration occurs causing shorting and IR characteristic degradation
Solution Approach 1:
The patent applies parameter changes by controlling the organic material content parameter within 5-20 wt% and the compressibility parameter to achieve cumulative height difference of 10 μm or less. This parameter control prevents electric field concentration while maintaining manufacturing simplicity, as the controlled compression behavior eliminates the need for complex post-processing steps to correct height variations.
Data Source
AI summary
A multilayer ceramic capacitor includes a capacitor body in which inner electrodes and dielectric layers are alternately laminated, and a length difference rate (D) of the inner electrodes is 7% or less. The length difference rate (D) is defined by D={L−1}/L×100, where L is a maximum length of the inner electrode, and l is a minimum length of the inner electrode.