Multilayer Ceramic Capacitor Cover Layers With Nickel Segregation
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Solution Overview
Problem
Existing multilayer ceramic capacitors face issues with cracks in the cover layers due to external stress concentration and short-circuiting between terminal electrodes, particularly as they become smaller in size and the cover layers thin, which are not adequately addressed by previous technologies.
Innovation Solution
The formation of terminal electrodes containing nickel as a main component element through physical vapor deposition or thermal spraying methods, resulting in nickel segregation regions in the cover layers that absorb and relax stress, preventing cracks and ensuring electrical insulation to prevent short-circuiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the capacitor size is reduced and cover layers are thinned to achieve miniaturization, then the productivity and compactness are improved, but the cover layers become susceptible to cracks under external stress
Solution Approach 1:
The patent applies local quality by creating nickel segregation regions specifically in the terminal electrode facing portions of the cover layers, where stress concentration occurs. These regions have different nickel concentrations (0.01-10 wt%) compared to the surrounding areas, providing localized stress absorption capacity exactly where needed during mounting processes, thereby preventing cracks while maintaining overall miniaturization benefits.
Solution Approach 2:
The patent implements beforehand cushioning by pre-forming nickel segregation regions in the cover layers before the capacitor is mounted. These regions act as stress buffers that absorb external stress during subsequent mounting processes, preventing crack propagation in the thinned cover layers and ensuring reliability in miniaturized capacitors.
2Ease of manufacture
If conventional manufacturing methods are used without nickel segregation control, then the manufacturing process is simpler, but short-circuiting between terminal electrodes occurs due to stress-induced cracks
Solution Approach 1:
The patent applies parameter changes by controlling the nickel concentration distribution in the cover layers, creating regions with 0.01-10 wt% nickel specifically in the terminal electrode facing portions. This parameter modification prevents stress-induced cracks that would cause short-circuiting, thereby improving electrical insulation reliability between terminal electrodes while maintaining manufacturing feasibility through controlled sintering processes.
3Ease of manufacture
If nickel is uniformly distributed in the cover layers, then the manufacturing process is easier, but stress concentration still causes cracks and short-circuiting
Solution Approach 1:
The patent implements local quality by creating non-uniform nickel distribution with specific segregation regions in the terminal electrode facing portions of the cover layers. These regions have elevated nickel concentrations (0.01-10 wt%) that provide localized stress absorption capacity, preventing cracks and short-circuiting while maintaining overall manufacturing feasibility through controlled sintering processes.
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 nickel segregation regions effectively suppress cracks in the cover layers and prevent short-circuiting between terminal electrodes, enhancing the reliability and performance of the multilayer ceramic capacitors under stress conditions.
Implementation Method 1
nickel segregation regions each having a maximum dimension of 0.4 μm or more and having a nickel concentration higher than surroundings... effectively suppress cracks in the cover layers and prevent short-circuiting between terminal electrodes, enhancing the reliability and performance... under stress conditions
Implementation Method 2
The formation of terminal electrodes containing nickel as a main component element through physical vapor deposition or thermal spraying methods
Implementation Method 3
The formation of terminal electrodes containing nickel as a main component element through physical vapor deposition or thermal spraying methods
Data Source
AI summary
A multilayer ceramic capacitor includes a plurality of terminal electrodes containing a metal having nickel as a main component element on the surface of at least one cover layer of a multilayer chip. Each of terminal electrode facing portions has nickel segregation regions each having a maximum dimension of 0.4 μm or more and having a nickel concentration higher than surroundings in an element distribution map generated by measuring a concentration distribution of nickel in any cross section parallel to the lamination direction, and a density of a nickel segregation region having a maximum dimension of 0.5 μm or more in the nickel segregation regions is 0.015 or more per 1 μm2. In a terminal electrode non-facing portion, a density of the nickel segregation region having the maximum dimension of 0.5 μm or more is 0.008 or less per 1 μm2 in the element distribution map.