MLCC Internal Electrode Layout for Moisture Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multilayer ceramic capacitors face reduced moisture resistance reliability due to moisture entering the interface between principal surfaces and external electrodes, potentially reaching internal electrodes.
Innovation Solution
The design includes internal electrode layers with a narrower lead-out portion width than the opposing portion, deviations in the width direction between adjacent layers, and segregation of Si or Mg at specific end portions and surfaces to enhance moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lead-out portion of internal electrode layers is made narrower, then moisture resistance reliability is improved, but the electrical connection area is reduced
Solution Approach 1:
The patent applies local quality by creating different width sections within the internal electrode layer: the lead-out portion has a narrower width than the opposing portion. This local variation in geometry allows the lead-out portion to increase moisture path length while the opposing portion maintains sufficient width for electrical connection, thus resolving the contradiction between moisture resistance and electrical connection area.
2Reliability
If Si or Mg segregation is introduced at end portions and principal surfaces, then insulation properties are enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition distribution within the internal electrode layer through Si or Mg segregation. By controlling the concentration and distribution of these elements at specific locations (end portions and principal surfaces), the insulation properties are enhanced. This compositional parameter change is integrated into the existing sintering process, avoiding major manufacturing complexity increases.
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 configuration improves the moisture resistance reliability by preventing moisture from reaching internal electrodes, increasing connection efficiency, and enhancing insulation properties.
Implementation Method 1
Si or Mg may be segregated in both of the end portions of the lead-out portion in the width direction. Si may be segregated on a principal surface of the lead-out portion on one side in the thickness direction. Mg may be segregated on a principal surface of the lead-out portion on one side in the thickness direction.
Data Source
AI summary
A multilayer ceramic capacitor includes an element body portion including dielectric layers and internal electrode layers, and external electrodes. In a cross section of the element body portion extending through a central portion in a length direction, a deviation amount in a width direction between internal electrode layers adjacent to each other in a thickness direction is smaller than about 3 μm, each of the internal electrode layers includes an opposing portion opposed to the internal electrode layer, and a lead-out portion, a width of the opposing portion is greater than a width of the lead-out portion, a region of the element body portion where the lead-out portions overlap in the thickness direction includes a thick portion thicker than the central portion in the length direction, and end portions of the lead-out portions in the thickness direction deviate by about 3 μm or more in the width direction.