Multilayer Ceramic Capacitor Electrode Stress Management
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Solution Overview
Problem
Multilayer ceramic electronic components face issues with residual stress due to material differences between internal electrode layers and ceramic layers, leading to potential cracking or peeling at the interface, especially under temperature variations.
Innovation Solution
The design incorporates internal electrode layers with peripheral electrodes made of a metallic species differing by more than 50% from the inside electrodes, reducing contraction differences and incorporating specific dimensions and coefficients of linear expansion to mitigate stress, along with external electrodes and underlying layers for enhanced structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal electrode layers and ceramic layers are made of different materials to achieve electrical functionality, then the electrical performance is improved, but residual stress increases due to differences in material properties and coefficient of thermal expansion
Solution Approach 1:
The patent applies different metallic species to different regions of the internal electrode layer. The peripheral portion uses a first metallic species while the inner portion uses a second metallic species, creating local quality variations that address different functional requirements - electrical conductivity where needed and stress management at the periphery
Solution Approach 2:
The internal electrode layer is constructed as a composite structure with two different metallic species in different regions. This composite approach allows the electrode to simultaneously achieve electrical functionality through the conductive metallic species while managing thermal stress through the peripheral metallic species with matched thermal expansion properties
2Ease of manufacture
If the coefficient of thermal expansion difference between internal electrode layer and ceramic layer is large to achieve material compatibility, then manufacturing is simplified, but distortion increases at varying temperatures leading to cracking or peeling
Solution Approach 1:
The patent addresses the thermal expansion mismatch problem locally at the peripheral portion of the internal electrode layer by using a first metallic species specifically in this region. This local quality change allows the peripheral area to have thermal expansion properties matched to the ceramic layer, preventing interface failure while the inner portion maintains electrical functionality
Solution Approach 2:
The patent changes the material parameter (metallic species composition) of the internal electrode layer at different locations. By selecting a first metallic species for the peripheral portion with thermal expansion properties matched to the ceramic layer, the patent optimizes the thermal-mechanical parameters to prevent distortion and interface failure
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 reduces residual stress, prevents cracking or peeling, and minimizes equivalent series resistance, enhancing the reliability and performance of multilayer ceramic capacitors.
Implementation Method 1
internal electrode layer 56 and ceramic layer 54 greatly differ in coefficient of thermal expansion. As a result, a distortion increases due to a difference in the contraction amount between internal electrode layer 56 and ceramic layer 54 at varying temperatures.
Data Source
AI summary
A multilayer ceramic electronic component includes an internal electrode layer including, on a same ceramic layer, a peripheral internal electrode having a frame shape and an inside internal electrode located inside the peripheral internal electrode. A metallic species included in the peripheral internal electrode is different from a metallic species included in the inside internal electrode. The metallic species included in the peripheral internal electrode includes more than or equal to about 50% of a metallic species different from the metallic species included in the inside internal electrode. In a width direction, a dimension a of a width of the peripheral internal electrode is about 5 μm<a<about 30 μm, and a dimension b of a width of the inside internal electrode is b/a≥about 20.