Multilayer Ceramic Capacitor Porosity Layout for Crack Containment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multilayer ceramic capacitors suffer from cracks forming at pores, which can propagate to internal electrode layers, leading to insulation degradation and dielectric breakdown.
Innovation Solution
The capacitors are designed with dielectric layers having unevenly distributed pores, where some layers have lower porosity for high insulating performance and others have higher porosity to preferentially generate cracks at interfaces, preventing crack propagation to internal electrode layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pores are present in dielectric layers, then manufacturing is easier and cost is reduced, but cracks form from pores leading to insulation degradation
Solution Approach 1:
The patent applies local quality by creating different pore area occupancy percentages in different dielectric layers. Outer dielectric layers have lower pore area occupancy (0.1-10%) while inner dielectric layers have higher pore area occupancy (5-30%). This local differentiation allows the outer layers to provide high insulation performance while inner layers facilitate controlled crack propagation away from internal electrodes, thus resolving the contradiction between ease of manufacture and reliability.
2Device complexity
If pores are uniformly distributed in dielectric layers, then manufacturing is simplified, but cracks can propagate through pores to internal electrode layer
Solution Approach 1:
The patent segments the dielectric layers into different types based on their pore area occupancy percentages. The capacitor structure includes outer dielectric layers with lower porosity and inner dielectric layers with higher porosity. This segmentation creates a layered defense system where cracks are preferentially generated and propagated in the inner layers with higher porosity, preventing them from reaching the internal electrode layers and causing insulation degradation.
Solution Approach 2:
Different regions of the dielectric structure are assigned different pore area occupancy percentages. The outer dielectric layers have pore area occupancy of 0.1-10% while inner dielectric layers have 5-30%. This local quality differentiation ensures that cracks originate and propagate in the inner high-porosity layers, protecting the internal electrodes from crack-induced insulation failure while maintaining manufacturing simplicity.
3Reliability
If outer dielectric layers have low porosity, then insulation performance is improved, but crack resistance is reduced
Solution Approach 1:
The inner dielectric layers with higher pore area occupancy (5-30%) act as intermediary layers that absorb and redirect crack propagation energy. These layers serve as a buffer zone between external stress sources and the critical internal electrode layers. When cracks occur, they are preferentially generated and propagated in the inner high-porosity layers, which act as sacrificial elements protecting the overall insulation performance of the capacitor.
Solution Approach 2:
The patent creates a gradient structure where outer dielectric layers have low porosity (0.1-10%) for high insulation performance while inner dielectric layers have high porosity (5-30%) for crack resistance. This local quality differentiation allows each layer to perform its specialized function: outer layers maintain electrical insulation while inner layers provide mechanical protection against crack propagation to the internal electrodes.
Data Source
AI summary
A multilayer ceramic capacitor includes a multilayer body including stacked dielectric layers, first and second internal electrode layers respectively exposed at first and second end surfaces and a second internal electrode layer, and first and second external electrodes. The multilayer body includes an internal layer portion in which the first and second internal electrode layers are opposed. The dielectric layers include voids segregated in the dielectric layers. The dielectric layers include void-containing dielectric layers which are different from each other in an area occupancy of voids in respective cross-sections of the dielectric layers.