Multilayer Ceramic Capacitor Asymmetric Cover Layer Mn Doping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors experience acoustic noise and reliability issues due to thickness differences between cover layers, leading to potential cracking and insufficient sintering, which degrades their performance.
Innovation Solution
A multilayer ceramic capacitor design with a thicker first cover layer and a thinner second cover layer, where the concentration of Mn in the first cover layer is higher than in the dielectric layers, to reduce the densifying start temperature difference and promote densification, thereby suppressing acoustic noise and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the lower cover layer is made thicker to suppress acoustic noise, then acoustic noise is reduced, but the densifying start temperature difference between the effective capacity region and the cover layer increases, causing cracks at the interface and insufficient sintering
Solution Approach 1:
The patent applies local quality by adding Mn specifically to the lower cover layer (the thicker layer) while keeping the upper cover layer and effective capacity region with standard composition. This localized compositional modification allows the lower cover layer to have a lower densifying start temperature, enabling it to densify properly during sintering without causing interface cracks, while maintaining the asymmetric thickness structure needed for acoustic noise suppression
Solution Approach 2:
The patent changes the chemical composition parameter by increasing Mn concentration in the lower cover layer. This parameter change directly affects the densifying start temperature, lowering it to match the effective capacity region's sintering behavior. This resolves the contradiction by allowing the thicker lower cover layer to densify properly without creating temperature differential stresses that would cause cracking
2Object-affected harmful factors
If the lower cover layer thickness is increased to suppress acoustic noise, then acoustic noise suppression is improved, but sufficient sintering cannot be achieved in the cover layer
Solution Approach 1:
The patent applies local quality by modifying the composition of only the lower cover layer with additional Mn, while keeping the upper cover layer and effective capacity region with standard composition. This localized modification ensures that the thicker lower cover layer has the appropriate densifying characteristics to achieve sufficient sintering, while maintaining the asymmetric thickness structure needed for acoustic noise suppression
Solution Approach 2:
The patent changes the chemical composition parameter (Mn concentration) in the lower cover layer to alter its thermal behavior during sintering. This parameter change lowers the densifying start temperature, enabling the thicker lower cover layer to achieve sufficient densification and sintering quality without compromising the acoustic noise suppression benefit
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 design effectively reduces acoustic noise and prevents cracking by ensuring sufficient densification of the cover layers, improving the overall reliability of the multilayer ceramic capacitors.
Implementation Method 1
a densifying start temperature of the cover layer tends to be higher than that of an effective capacity region
Implementation Method 2
extension and contraction caused by electrostriction may occur in the multilayer ceramic capacitor
Data Source
AI summary
A multilayer ceramic capacitor includes: a multilayer structure having a parallelepiped shape in which each of a plurality of dielectric layers and each of a plurality of internal electrode layers are alternately stacked and are alternately exposed to two edge faces of the multilayer structure, a main component of the plurality of dielectric layers being a ceramic; and a first cover layer and a second cover layer that sandwich the multilayer structure in a stacking direction of the multilayer structure, a main component of the first cover layer and the second cover layer being the same as that of the dielectric layers, wherein the first cover layer includes a first region spaced from the multilayer structure by at least 50 μm, is thicker than the second cover layer, and has a thickness more than 50 μm.