Multilayer Ceramic Capacitor Base Electrode Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The glass components containing Si or B in external electrodes of multilayer ceramic capacitors tend to precipitate, increasing Equivalent Series Resistance (ESR) in high frequency ranges and degrading the adherence intensity of plated layers, leading to reliability issues such as solder burst and reduced performance.
Innovation Solution
A multilayer ceramic capacitor design with a base conductive layer composed of noble metals or transition metals other than the iron group, where the total concentration of Si and B in the second-phase is 0.3 wt % or less, reducing precipitation and enhancing high-frequency characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If glass components including Si or B are added to the conductive paste for forming an external electrode, then the sintering temperature of the external electrode is decreased and adhesive force of the terminal electrode is secured, but the glass component precipitates in the interface between internal electrode layers and the external electrode, increasing ESR in high frequency range
Solution Approach 1:
The patent changes the chemical composition parameters of the conductive paste by strictly limiting Si content to 0.05 wt% or less and B content to 0.05 wt% or less. This parameter control prevents glass component precipitation while maintaining adequate sintering temperature and adhesive force, thereby resolving the contradiction between lowering sintering temperature and maintaining high-frequency reliability.
Solution Approach 2:
The patent applies different composition requirements to different regions of the external electrode system. By controlling the base conductive layer composition to have minimal Si and B, the patent ensures that the interface region with internal electrode layers does not develop precipitated glass components, while still achieving proper bonding through controlled sintering.
2Ease of manufacture
If glass components are dissolved during plating process, then voids are generated in the plated layer, but plating solution intrudes in the void causing burst of solder and reduction of reliability
Solution Approach 1:
The patent takes preliminary action by controlling the base conductive layer composition to have minimal Si (0.05 wt% or less) and B (0.05 wt% or less) before the plating process. This preliminary composition control prevents glass component dissolution and void formation during plating, thereby preventing plating solution intrusion and subsequent solder burst, resolving the contradiction between plating process feasibility and reliability.
Data Source
AI summary
A multilayer ceramic capacitor includes: a ceramic multilayer structure designated to have ceramic dielectric layers and internal electrode layers alternately stacked, the internal electrode layers being mainly composed of a transition metal other than an iron group, end edges of the internal electrode layers being alternately exposed to a first end face and a second end face; and a pair of external electrodes provided on the first end face and the second end face, wherein: the external electrodes have a base conductive layer and a first plated layer; the base conductive layer directly contacts the ceramic multilayer structure; a main component of the base conductive layer is a noble metal or a transition metal other than an iron group; and a total concentration of Si and B in a second-phase not contacting the ceramic multilayer structure is 0.3 wt % or less, in the base conductive layer.