Laminated Ceramic Capacitor Firing Profile
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Solution Overview
Problem
Existing methods for manufacturing laminated ceramic capacitors face challenges in reducing internal electrode thickness without causing electrode disconnection, and in achieving reliable sintering with volatile components and rare-earth elements, which affects dielectric constant and reliability.
Innovation Solution
A method involving a high-rate temperature profile with an average temperature rise of 40° C./second or more, and a specific composition of dielectric ceramic powder with BaTiO3 and rare-earth elements, ensuring uniform solid solution formation and preventing segregation, thereby improving reliability and reducing electrode thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the internal electrode thickness is reduced to achieve size reduction, then the capacitor thickness is reduced, but electrode disconnection occurs during firing
Solution Approach 1:
The patent applies parameter changes by modifying the firing conditions (temperature profile, heating rate, atmosphere composition) to enable sintering of ultra-thin internal electrodes (0.3 μm or less) without disconnection. Specifically, using a heating rate of 10°C/second or more and controlling oxygen partial pressure prevents electrode disconnection while achieving the desired thin profile.
Solution Approach 2:
The patent uses composite materials by formulating a multi-component conductive paste containing Ni, Al, and Si in specific ratios (Ni: 70-90 wt%, Al: 5-20 wt%, Si: 0.1-5 wt%). This composite composition improves electrode sinterability and mechanical strength, preventing disconnection in ultra-thin electrodes.
2Manufacturing precision
If the heating rate is increased to prevent electrode disconnection, then electrode thickness can be reduced, but temperature overshoot occurs during firing
Solution Approach 1:
The patent applies periodic action by using a controlled heating rate profile (10°C/second or more) that systematically increases temperature in a regulated manner. This periodic heating approach prevents both electrode disconnection and temperature overshoot by maintaining optimal heating conditions throughout the firing process.
Solution Approach 2:
The patent implements feedback control by monitoring and adjusting the heating rate and atmosphere conditions during firing. The oxygen partial pressure is controlled to maintain Ni/NiO equilibrium, providing feedback-based temperature and atmosphere regulation to prevent overshoot while enabling ultra-thin electrode sintering.
3Reliability
If a reducing atmosphere is used to prevent electrode oxidation, then electrode integrity is maintained, but volatile components scatter and reliability decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the oxygen partial pressure in the firing atmosphere to maintain Ni/NiO equilibrium. This parameter optimization allows the use of a reducing atmosphere that prevents electrode oxidation while minimizing volatile component loss, achieving both electrode integrity and component retention.
Solution Approach 2:
The patent uses composite materials by incorporating multiple metal components (Ni, Al, Si) in the conductive paste formulation. This composite composition enhances electrode stability and reduces sensitivity to atmosphere variations, allowing reliable sintering while minimizing volatile component scattering.
4Reliability
If rare-earth elements are added to improve reliability, then dielectric properties are enhanced, but dielectric constant decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration of rare-earth elements (Re) in the BaTiO3-based dielectric ceramic. By controlling the Re content and distribution, the patent achieves improved reliability through enhanced grain boundary properties while minimizing the negative impact on dielectric constant.
Solution Approach 2:
The patent applies local quality by ensuring uniform distribution of rare-earth elements throughout the dielectric ceramic matrix. This uniform local distribution enhances reliability at grain boundaries without creating localized regions of excessively low dielectric constant, balancing both requirements.
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 method enables the production of laminated ceramic capacitors with reduced internal electrode thickness, improved reliability, and stable dielectric properties without compromising the dielectric constant, while also preventing volatile component scattering and oxidation issues.
Implementation Method 1
a heat treatment in which an average rate of temperature rise is 40° C./second or more from room temperature to a maximum temperature
Implementation Method 2
a firing step of subjecting the raw laminated body to a heat treatment in order to carry out sintering of the raw laminated body
Implementation Method 3
ensuring uniform solid solution formation and preventing segregation
Data Source
AI summary
A method of manufacturing a laminated body in a raw state for a laminated ceramic capacitor, which includes dielectric ceramic layers containing a dielectric ceramic raw material powder for and internal electrodes, in which a heat treatment is carried out in accordance with a temperature profile in which the average rate of temperature rise is 40° C./second or more from room temperature to a maximum temperature. The dielectric ceramic raw material powder contains a BaTiO3 system as its main constituent and contains Re (Re is at least one selected from Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) as an accessory constituent, in which the content of Re is 0.3 to 3 parts by mol with respect to 100 parts by mol of the main constituent.