MLCC Internal Electrode Sulfur Interface to Prevent Balling
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Solution Overview
Problem
Thinning of internal electrode layers in multilayer ceramic capacitors leads to a local increase in electric field intensity due to balling of main component metal particles, resulting in reduced reliability and lifespan of the capacitors.
Innovation Solution
Coating the main component metal of the internal electrode layers with sulfur (S) to reduce or prevent balling, thereby minimizing the local increase in electric field intensity and maintaining the reliability and lifespan of the capacitors. This creates a solid solution layer at the interface between dielectric columns and internal electrode layers, enhancing insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the internal electrode layers are thinned to reduce capacitor size and increase capacitance, then the number of laminated layers can be increased and capacitor capacity improved, but balling of metal particles occurs causing local electric field intensity increase and reliability decrease
Solution Approach 1:
A solid solution layer containing sulfur is introduced as an intermediary between the dielectric columns and the internal electrode layers. This intermediate layer prevents direct contact and interaction that would otherwise cause balling of metal particles, thereby eliminating the root cause of local electric field intensity increase while maintaining the thinned electrode structure.
Solution Approach 2:
The chemical composition of the interface between dielectric columns and internal electrode layers is modified by introducing sulfur into a solid solution layer. This parameter change (adding sulfur element) fundamentally alters the physical and electrical properties at the interface, preventing metal particle balling and the associated reliability issues.
2Manufacturing precision
If the internal electrode layers are thinned, then manufacturing precision and layer density can be improved, but the life and reliability of the multilayer ceramic capacitor decrease due to electric field concentration
Solution Approach 1:
The solid solution layer with sulfur acts as a protective intermediary that prevents the harmful interaction between dielectric columns and internal electrode layers. This intermediary structure maintains the precision of thinned layers while protecting against the reliability-degrading effects of electric field concentration.
Solution Approach 2:
The sulfur-containing solid solution layer is formed in advance during the manufacturing process, before the capacitor is put into service. This pre-formed protective layer cushions against future reliability issues by preventing balling and electric field concentration from the outset, thereby extending capacitor lifespan.
3Reliability
If conductive layers are added between internal electrode layers to prevent short circuits, then reliability can be improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of adding conductive layers throughout, the invention applies a localized solid solution layer with sulfur only at specific interfaces between dielectric columns and internal electrode layers. This localized approach provides the necessary reliability improvement while minimizing the increase in overall device complexity.
Solution Approach 2:
The solid solution layer is a composite material combining sulfur with the existing electrode layer materials. This composite structure provides both the electrical insulation needed to prevent short circuits and the chemical properties to prevent balling, achieving reliability improvement without requiring separate additional conductive layers.
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 coating of internal electrode layers with sulfur effectively reduces the decrease in reliability and lifespan of multilayer ceramic capacitors by minimizing electric field concentration and improving insulation properties, thus maintaining capacitor performance.
Implementation Method 1
a solid solution layer in which S is solidly dissolved is provided at the interface between the dielectric columns in the internal electrode layers and the internal electrode layers
Implementation Method 2
the electric field intensity locally increases in the dielectric layer due to balling (formation of balls) of the main component metal particles of the internal electrode layer
Data Source
AI summary
A multilayer ceramic capacitor includes dielectric layers made of a ceramic material and internal electrode layers laminated therein. The internal electrode layers each include dielectric columns provided therein. A solid solution layer in which S is solidly dissolved is provided at an interface between each of the dielectric columns and each of the internal electrode layers.