Dielectric Ceramic Composition for Multilayer Capacitor Bondability
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Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in securing bondability between internal and external electrode layers and dielectric layers while maintaining COG characteristics and ensuring moisture resistance reliability.
Innovation Solution
A dielectric ceramic composition comprising a perovskite compound with Sr and Zr, optionally including Ca and Ti, further containing Li and Si, and potentially Mn, is used, with specific molar ratios to ensure bondability and COG characteristics, along with a multilayer ceramic capacitor design featuring internal and external electrodes with a baked glass frit and metal plating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reduction resistant dielectric composition is used, then moisture resistance reliability is improved, but bondability between internal electrode layer and dielectric layer deteriorates
Solution Approach 1:
The patent modifies the chemical composition parameters of the dielectric layer by incorporating specific amounts of Li (0.01-5 wt%), Si (0.01-5 wt%), and Mn (0.01-5 wt%) along with the perovskite compound. These parameter changes enable the dielectric layer to achieve both reduced reduction resistance (improving bondability) and maintained moisture resistance reliability, resolving the technical contradiction between these two properties.
Solution Approach 2:
The patent creates a composite dielectric composition by combining the perovskite compound (Ca1-xSrx)m(Zr1-yTiy)O3 with Li, Si, and Mn additives. This composite material structure allows the dielectric layer to exhibit both good bondability with internal electrodes and high moisture resistance, simultaneously achieving properties that were previously contradictory when using reduction resistant compositions alone.
2Reliability
If a reduction resistant dielectric composition is used, then moisture resistance reliability is improved, but bondability between external electrode and dielectric layer deteriorates
Solution Approach 1:
The patent adjusts the chemical composition parameters of the dielectric layer by incorporating specific amounts of Li (0.01-5 wt%), Si (0.01-5 wt%), and Mn (0.01-5 wt%). These parameter modifications enable the dielectric layer to maintain both reduced reduction resistance (improving external electrode bondability) and high moisture resistance reliability, resolving the contradiction between these two properties.
Solution Approach 2:
The patent develops a composite dielectric material combining the perovskite compound with Li, Si, and Mn additives. This composite structure enables the dielectric layer to achieve both good bondability with external electrodes and high moisture resistance, simultaneously attaining properties that were previously contradictory in reduction resistant compositions.
3Strength
If bondability is improved by adjusting dielectric composition, then COG characteristic deteriorates
Solution Approach 1:
The patent precisely controls the composition parameters within specific ranges: Li (0.01-5 wt%), Si (0.01-5 wt%), Mn (0.01-5 wt%), and perovskite compound (90-99.98 wt%). This careful parameter optimization enables the dielectric layer to achieve good bondability while maintaining the COG characteristic, resolving the contradiction between bondability improvement and COG stability.
Solution Approach 2:
The patent introduces different functional components at specific locations within the dielectric composition: Li, Si, and Mn are added in controlled amounts to specific regions of the dielectric layer to enhance bondability locally, while the overall perovskite compound composition (Ca1-xSrx)m(Zr1-yTiy)O3 maintains the COG characteristic. This localized quality differentiation resolves the contradiction between local bondability improvement and global COG stability.
Data Source
AI summary
A dielectric ceramic composition includes, as a main component, a perovskite compound containing Sr and Zr and may contain Ca and/or Ti, further contains Li and Si, and may contain Mn. When a total content of Zr and Ti is 100 parts by mol, a total content (100×m) of parts by mol of Sr and Ca is 0.8≤m≤1.3, a content a of parts by mol of Mn is 0≤a≤10, a content b of parts by mol of Li is 5≤b≤15, a content c of parts by mol of Si is 20≤c≤40, a molar ratio x of Ca/(Sr+Ca) is 0≤x≤0.8, and a molar ratio y of Ti/(Zr+Ti) is 0≤y≤0.5.