BaTiO3 Dielectric Composition for X7R Capacitor Reliability
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Solution Overview
Problem
Ceramic capacitors face challenges in achieving both capacity stability and high reliability, especially under high temperature conditions, as existing technologies struggle to maintain performance within the X7R characteristic of the EIA standard.
Innovation Solution
A ceramic capacitor with a multilayer structure using dielectric layers composed of ceramic with specific sub-components such as Mn, Mg, rare earth elements, V, Si, and Ca, within precise concentration ranges, and an average grain diameter of 280-380 nm, along with a manufacturing method that includes forming a green sheet and firing under controlled conditions to achieve these specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the dielectric material composition is adjusted to satisfy X7R characteristic, then capacity stability is improved, but high reliability under high temperature load cannot be achieved
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of multiple sub-components (Mn: 0.05-0.35 atom%, Mg: 0.40-0.80 atom%, rare earth elements: 0.50-0.90 atom%, V: 0.15-0.30 atom%, Si: 0.40-0.90 atom%, Ca: 0.00-0.45 atom%) in the barium titanate-based dielectric material. This multi-parameter optimization enables simultaneous achievement of X7R capacity stability and high reliability under high temperature load, resolving the technical contradiction between capacity stability and reliability.
Solution Approach 2:
The patent uses composite materials by combining barium titanate (BamTiO3 with 0.9990≤m≤1.0015) with multiple oxide sub-components (MnO, MgO, rare earth oxides, V2O5, SiO2, CaO) to create a complex dielectric system. This composite approach allows the material to simultaneously exhibit capacity stability and high reliability properties that cannot be achieved with single-component materials.
2Manufacturing precision
If the average grain diameter is controlled within 280-380 nm, then both capacity stability and high reliability are achieved
Solution Approach 1:
The patent controls the average grain diameter parameter within the specific range of 280-380 nm through precise sintering condition optimization. This parameter control is critical for achieving both capacity stability and high reliability, as it affects the dielectric properties and mechanical strength of the ceramic capacitor under high temperature conditions.
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 solution enables both capacity stability and high reliability of ceramic capacitors, meeting the X7R characteristic by optimizing the composition and microstructure of the dielectric layers, thereby enhancing their performance under high temperature conditions.
Implementation Method 1
a main component of the plurality of dielectric layers is ceramic having a perovskite structure expressed by BamTiO3 (0.9990≤m≤1.0015)
Implementation Method 2
firing the green sheet on which the metal conductive paste was arranged, wherein a condition of the firing is adjusted so that an average grain diameter of the BamTiO3 is 280 nm or more and 380 nm or less in dielectric layers formed in the firing
Data Source
AI summary
A ceramic capacitor includes: a multilayer structure in which each of a plurality of dielectric layers and each of a plurality of internal electrode layers are alternately stacked, wherein a main component of the plurality of dielectric layers is BaTiO3, wherein the plurality of dielectric layers include Mn as a first sub-component, Mg as a second sub-component, a rare earth element which is at least one of Ho and Dy as a third sub-component, V as a fourth sub-component, Si as a fifth sub-component, Ca as a sixth sub-component, wherein an average grain diameter of ceramic grains of the plurality of dielectric layers is 280 nm or more and 380 nm or less.