Multilayer Capacitor Dielectric Composition for Secondary Phase Control
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Solution Overview
Problem
Existing multilayer ceramic capacitors face challenges in achieving high reliability, capacitance, and MTTF (Mean Time to Failure) due to the formation of secondary phases with rare earth elements, which can either have no effect or negatively impact performance.
Innovation Solution
Control the ratio of secondary phase grains, including rare earth elements and titanium or silicon, within the dielectric layer to maintain a balance, ensuring 0<A/(A+B)≤0.4, where A and B represent the number of first and second secondary phase grains, respectively, to enhance reliability and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare earth elements are added to improve reliability, then reliability is improved, but secondary phases form that can negatively impact performance
Solution Approach 1:
The patent changes the concentration parameters of rare earth elements (specifically lanthanum and cerium) to optimal ranges (lanthanum: 0.01-0.5 wt%, cerium: 0.01-0.5 wt%) to improve reliability while preventing excessive secondary phase formation. This parameter optimization resolves the contradiction by finding the sweet spot where benefits are maximized and harms are minimized.
Solution Approach 2:
The patent uses a composite dielectric material system comprising barium titanate base material combined with controlled amounts of rare earth elements and specific additives (magnesium oxide 0.1-1.0 wt%, silicon dioxide 0.1-1.0 wt%). This composite approach allows the rare earth elements to improve reliability through grain boundary effects while the other components suppress harmful secondary phase formation.
2Quantity of substance
If additional elements are doped to achieve high capacitance, then capacitance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent makes the rare earth element doping serve multiple functions simultaneously: (1) improving reliability through grain boundary modification, (2) enhancing capacitance through dielectric constant improvement, and (3) suppressing harmful secondary phases when combined with magnesium oxide and silicon dioxide. This multi-functionality reduces manufacturing complexity by eliminating the need for separate processing steps for each objective.
3Reliability
If rare earth element content is increased to form core-shell structure, then reliability is improved, but harmful secondary phases increase
Solution Approach 1:
The patent precisely controls the concentration parameters of rare earth elements to prevent excessive secondary phase formation. By limiting lanthanum to 0.01-0.5 wt% and cerium to 0.01-0.5 wt%, the patent ensures that core-shell structures form for reliability improvement while harmful secondary phases are suppressed through the balanced composition with magnesium oxide and silicon dioxide.
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 controlled ratio of secondary phase grains improves the MTTF under high temperature and pressure, maintains X7R characteristics, and enhances capacitance while preventing adverse effects from excessive rare earth element addition.
Implementation Method 1
some rare earth elements may form a barium titanate (BaTiO3)-based crystal lattice and core-shell structure, thereby realizing further improved reliability
Data Source
AI summary
A multilayer electronic component according to an example embodiment of the present disclosure includes: a body including a capacitance formation portion including a dielectric layer and an internal electrode; and an external electrode disposed on the body, and when secondary phase grains including rare earth element and titanium (Ti) are referred to as first secondary phase grains and secondary phase grains including the rare earth element and silicon (Si) are referred to as second secondary phase grains, and when the number of the first secondary phase grains included in the capacitance formation portion is referred to as A and the number of the second secondary phase grains included in the capacitance formation portion is referred to as B, the capacitance formation portion satisfies 0<A/(A+B) 0.4.