Multilayer Ceramic Capacitor Reoxidation Oxygen Vacancy Reduction
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Solution Overview
Problem
Multilayer ceramic capacitors sintered under moderately-or-more reducing atmospheres for hydrogen exhibit a large number of oxygen vacancies, leading to undesirable decreases in reliability and capacitance characteristics, particularly in high-reliability applications such as vehicle components.
Innovation Solution
A method involving sintering dielectric layers with internal electrodes under a moderately-or-more reducing atmosphere for hydrogen, followed by a first and second reoxidation heat treatment under an oxidizing atmosphere to significantly reduce oxygen vacancies and fill pores with glass, thereby enhancing the reliability and hardness of the capacitor component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sintering is performed under a moderately-or-more reducing atmosphere for hydrogen, then high capacitance characteristics are achieved, but a large quantity of oxygen vacancies are formed inside dielectric layers causing reliability to decrease
Solution Approach 1:
The oxygen vacancies formed during reducing atmosphere sintering are converted from harmful defects into opportunities for controlled reoxidation treatment. The reoxidation heat treatment specifically targets and eliminates these oxygen vacancies, transforming the harmful byproduct of high-capacitance sintering into a controlled process step that ultimately improves reliability.
Solution Approach 2:
The reoxidation heat treatment is performed as a preliminary or follow-up action after sintering to prevent the harmful effects of oxygen vacancies from manifesting. By addressing oxygen vacancy formation in a dedicated subsequent step, the process ensures high reliability before the capacitor enters service.
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 approach effectively reduces oxygen vacancies and improves the reliability and hardness of multilayer ceramic capacitors, addressing the reliability issues associated with sintering under moderately-or-more reducing atmospheres while maintaining high capacitance characteristics.
Implementation Method 1
sintering a body in which a plurality of dielectric layers having internal electrodes printed thereon are laminated, under a moderately-or-more reducing atmosphere for hydrogen
Implementation Method 2
a first reoxidation operation of subjecting the sintered body to a first reoxidation heat treatment under an oxidizing atmosphere
Implementation Method 3
a substantial portion of the plurality of pores are filled with glass
Data Source
AI summary
A method for manufacturing a capacitor component includes an operation of sintering under a moderately-or-more reducing atmosphere for hydrogen, a body in which a plurality of dielectric layers having internal electrodes printed thereon are laminated,; a first reoxidation operation of subjecting the sintered body to a first reoxidation heat treatment under an oxidizing atmosphere; and a second reoxidation operation of subjecting the body having undergone the first reoxidation heat treatment to a second reoxidation heat treatment under an oxidizing atmosphere.