Dielectric Ceramic Composition for Multilayer Capacitor Reliability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multilayer ceramic capacitors using nonreducing dielectric materials face issues with insulation resistance degradation, short IR lifetime, and low reliability, especially under varying temperature conditions, and have a high capacity defect rate when attempting to improve high temperature accelerated lifetime.
Innovation Solution
A dielectric ceramic composition with barium titanate as the main component, including specific subcomponents such as MgO, Al2O3, V2O5, and CaZrO3, fired in a reducing atmosphere and annealed at 1000-1400°C under controlled oxygen partial pressure, to achieve high permittivity, X8R temperature characteristics, and improved high temperature accelerated lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nonreducing dielectric materials are used to maintain high specific resistance, then insulation resistance is improved, but IR lifetime becomes short and reliability deteriorates under varying temperature conditions
Solution Approach 1:
The patent uses a composite dielectric material system consisting of barium titanate (main component) combined with specific subcomponents (MgO, CaO, BaO, SrO, Al2O3, V2O5, MoO3, WO3, and rare earth oxides). This composite structure allows the material to simultaneously maintain high specific resistance and achieve long IR lifetime by creating a synergistic effect where the subcomponents modify the electrical and thermal properties of the barium titanate base material.
Solution Approach 2:
The patent optimizes multiple parameters including the precise compositional ratios of subcomponents (0.1-3 mol% for first subcomponent, 1-10 mol% for second subcomponent, 0.01-0.5 mol% for third subcomponent, 0.5-7 mol% for fourth subcomponent), firing temperature (1000-1400°C), and oxygen partial pressure during annealing (10^-21 to 10^-1 atm). These parameter changes enable the dielectric material to achieve both high insulation resistance and extended IR lifetime.
2Reliability
If annealing temperature is raised to improve high temperature accelerated lifetime, then reliability is improved, but capacity defect rate increases
Solution Approach 1:
The patent optimizes the annealing temperature within a specific range (1000-1400°C) and controls the oxygen partial pressure (10^-21 to 10^-1 atm) during the annealing process. By precisely controlling these parameters, the patent achieves improved high temperature accelerated lifetime while preventing excessive capacity defect rates that would occur at higher annealing temperatures.
Solution Approach 2:
The specific subcomponents (particularly Al2O3 and rare earth oxides) act as intermediaries during the annealing process, protecting the barium titanate grains from excessive growth and capacity defects while still allowing the annealing treatment to improve high temperature lifetime characteristics.
3Ease of manufacture
If base metals like Ni are used as conductive material to reduce cost, then manufacturing cost is reduced, but oxidation occurs in air firing requiring reducing atmosphere which reduces dielectric layers
Solution Approach 1:
The patent employs a reducing atmosphere (inert environment) during the simultaneous firing of internal electrode layers and dielectric layers. This controlling the oxygen partial pressure during firing prevents oxidation of the base metal conductive material while minimizing reduction of the dielectric layers through optimized process parameters.
Solution Approach 2:
The use of base metal conductive materials (Ni, Ni alloys) combined with the specifically formulated dielectric ceramic composition enables cost-effective manufacturing. The dielectric composition is designed to be compatible with base metals, allowing simultaneous firing in a reducing atmosphere without severe dielectric layer reduction.
4Volume of moving object
If capacitor size is reduced to meet miniaturization demands, then device size is reduced, but maintaining capacity and reliability under severe temperature conditions becomes difficult
Solution Approach 1:
The patent uses a composite dielectric material system with barium titanate and specific subcomponents that provides high permittivity and stable capacity-temperature characteristics. This allows miniaturization of the capacitor while maintaining the required capacity and reliability under severe temperature conditions including the X8R temperature range (-55 to 150°C).
Solution Approach 2:
The patent optimizes the compositional parameters of the dielectric ceramic (ratios of various oxides, total subcomponent content) to achieve high permittivity and stable temperature characteristics in thin dielectric layers, enabling capacitor miniaturization without sacrificing performance.
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 composition provides a multilayer ceramic capacitor with enhanced high temperature accelerated lifetime, reduced capacity defect rate, and stable capacity-temperature characteristics across a broad temperature range, meeting EIA X8R standards while maintaining high permittivity and reliability.
Implementation Method 1
if firing in a reducing atmosphere, the dielectric layers are reduced and the specific resistance declines
Implementation Method 2
annealing it at 1000 to 1400°C
Data Source
Figure 1
AI summary
A dielectric ceramic composition having at least a main component including barium titanate, a first subcomponent including at least one type of compound selected from MgO, CaO, BaO, and SrO, a second subcomponent including at least one type of compound selected from Al2O3, Li2O, and B2O3, a third subcomponent including at least one type of compound selected from V2O5, MoO3, and WO3, a fourth subcomponent including an oxide of R1 (where R1 is at least one type of element selected from Sc, Er, Tm, Yb, and Lu), and a fifth subcomponent including CaZrO3 or CaO+ZrO2.