Multilayer Ceramic Capacitor Mn/Ti Ratio Control
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Solution Overview
Problem
Conventional multilayer ceramic capacitors face issues with short circuits and decreased high-temperature load reliability due to level differences between dielectric ceramic and internal electrode layers, leading to cracking and chipping, especially as the number of layers increases.
Innovation Solution
A multilayer ceramic capacitor design with dielectric ceramic layers containing Ba, Ti, Mn, and a rare earth element, where the Mn/Ti peak intensity ratio is higher in outer layer portions compared to the central portion, reducing structural defects and enhancing high-temperature reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If internal electrode layers are made smaller in plane surface area than dielectric ceramic layers, then manufacturing is simplified, but level differences cause internal electrode layers to bend leading to short circuits and decreased high-temperature load reliability
Solution Approach 1:
The patent applies local quality by creating a non-uniform Mn distribution within the dielectric ceramic layers. The Mn concentration is specifically increased in outer layer portions compared to central portions, targeting the regions where level differences and bending occur most frequently. This localized compositional modification addresses the reliability issue at critical locations without requiring uniform changes throughout the entire structure, thus maintaining manufacturing simplicity while improving high-temperature load reliability.
2Quantity of substance
If thinner dielectric ceramic layers are provided and more layers are stacked, then capacitance is increased, but short circuits between internal electrode layers occur more frequently reducing reliability
Solution Approach 1:
The patent implements local quality by differentiating the Mn content between outer layer portions and central portions of the dielectric ceramic layers. Outer layers, which are more susceptible to bending and short circuits in multi-layer configurations, contain higher Mn concentrations that suppress grain growth and prevent short circuits. This allows the use of thinner dielectric layers with increased stacking while maintaining reliability through targeted compositional control at vulnerable locations.
Solution Approach 2:
The patent applies parameter changes by modifying the Mn concentration parameter within the dielectric ceramic composition. By increasing the Mn content in outer layer portions, the patent changes the physical and chemical properties of these regions to suppress grain growth and prevent short circuits, enabling higher layer counts with thinner dielectric layers while maintaining short circuit resistance.
3Manufacturing precision
If zero level difference sheets are used to eliminate level differences, then manufacturing precision is improved, but extremely small gaps still cause bent portions leading to cracking and chipping
Solution Approach 1:
The patent applies local quality by concentrating Mn in the outer layer portions of dielectric ceramic layers, specifically where bending and stress concentration occur due to residual gaps. This localized compositional modification strengthens the vulnerable regions, suppressing grain growth and preventing cracking and chipping at the locations most affected by manufacturing imperfections, while maintaining overall manufacturing precision.
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 minimizes structural defects, cracking, and chipping, while improving high-temperature load reliability by promoting Mn diffusion and suppressing grain growth, resulting in a more reliable capacitor.
Implementation Method 1
a value of the Mn/Ti peak intensity ratio in the dielectric ceramic layer in at least one of the main surface outer layer portion, the side surface outer layer portion, and the end surface outer layer portion is in a range of two times to fifteen times the value of the Mn/Ti peak intensity ratio in the dielectric ceramic layer in a central portion of the effective portion
Data Source
AI summary
In a multilayer ceramic capacitor, when a ratio of an ICP peak intensity of Mn to an ICP peak intensity of Ti is an Mn/Ti peak intensity ratio, a value of the Mn/Ti peak intensity ratio in a dielectric ceramic layer in at least one of a main surface outer layer portion, a side surface outer layer portion, and an end surface outer layer portion is in a range of two times to fifteen times a value of the Mn/Ti peak intensity ratio in a dielectric ceramic layer in a central portion of an effective portion in a width direction, a length direction, and a stacking direction.