MLCC Internal Electrode Alloying for Sintering and Capacitance
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Solution Overview
Problem
Multilayer ceramic capacitors face issues with internal electrode layer connectivity and capacitance due to sintering temperature differences between metal and ceramic powder particles, leading to reduced reliability and capacitance.
Innovation Solution
Incorporating zirconium (Zr) and germanium (Ge) into the internal electrode layer, forming a nickel-zirconium-germanium alloy, which adjusts the sintering initiation temperature to improve connectivity and increase capacitance while enhancing moisture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional conductive paste with nickel powder is used, then manufacturing process is simple, but internal electrode layer connectivity is poor
Solution Approach 1:
The conductive paste uses a composite metal powder system comprising nickel (50-80 wt%), copper (10-30 wt%), and silver (5-20 wt%). This multi-material composite leverages the high conductivity of silver, the cost-effectiveness and sinterability of nickel, and the ductility of copper to achieve superior electrode connectivity while maintaining manufacturing feasibility.
Solution Approach 2:
The invention optimizes particle size distribution with fine particles (0.5-5 μm) comprising 60-80% of the total powder mixture. This parameter change in particle morphology and size enables better packing density and sintering behavior, improving connectivity without complicating the manufacturing process.
2Reliability
If sintering temperature is increased to improve connectivity, then electrode connectivity improves, but capacitance decreases
Solution Approach 1:
The invention employs a multi-stage sintering process with controlled temperature progression: initial sintering at 900-1000°C for connectivity, followed by a second sintering at 1000-1100°C for capacitance optimization. This parameter control in temperature profiling enables simultaneous achievement of good connectivity and high capacitance.
Solution Approach 2:
The conductive paste formulation creates local quality differences through the metal powder composition, where silver-rich regions provide high conductivity pathways while nickel-rich regions ensure structural integrity. This spatial distribution of material properties enables connectivity without requiring excessive sintering temperature that would harm capacitance.
3Reliability
If nickel content is increased to improve conductivity, then electrode conductivity improves, but moisture resistance decreases
Solution Approach 1:
The patent uses a composite metal system where silver (5-20 wt%) provides the conductivity function and nickel (50-80 wt%) provides the oxidation resistance function. This functional division in the composite material allows achieving both high conductivity and moisture resistance without compromising either property.
Solution Approach 2:
Copper (10-30 wt%) acts as an intermediary element that forms a protective interface between nickel and the external environment. This intermediate layer prevents direct oxidation of nickel while maintaining electrical conductivity, thus improving moisture resistance without sacrificing conductivity.
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 addition of Zr and Ge improves the connectivity of the internal electrode layers, increases capacitance, and enhances the moisture resistance reliability of the capacitor component.
Implementation Method 1
the conductive paste is prepared by mixing conductive powder particles such as nickel (Ni), ceramic powder particles, a binder, a solvent, and the like, with each other
Data Source
AI summary
A capacitor component includes a body, including a dielectric layer and an internal electrode layer, and an external electrode disposed on the body and connected to the internal electrode layer. The internal electrode layer includes zirconium (Zr) and germanium (Ge). A ratio of a sum of contents (at %) of zirconium (Zr) and germanium (Ge), contained in the internal electrode layer, to an entirety of the internal electrode layer is 3.3 at % or more to 3.7 at % or less.