ABO3 Conductive Paste for Thin MLCC Inner Electrode Coverage
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Solution Overview
Problem
Existing conductive pastes for forming inner electrodes in multilayer ceramic capacitors face challenges in achieving high coverage when the electrodes are formed as thin layers, which hinders capacitance enhancement.
Innovation Solution
The use of a conductive paste comprising a ceramic powder of ABO3 type with a specified ionic radius ratio between the A-site element and the conductive metal powder, such as NiTiO3, MgTiO3, or MnTiO3, ensures high coverage even for thin electrodes by moderating the sintering reaction and improving heat resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the thickness of inner electrodes is reduced to form thin layers, then the size of multilayer ceramic capacitor is reduced, but the coverage of inner electrodes decreases
Solution Approach 1:
The patent changes the sintering temperature parameter by adding a common material to the conductive paste, shifting the sintering temperature of metal particles to be closer to the sintering temperature of the dielectric layer. This temperature parameter adjustment enables thin-layer inner electrodes to achieve high coverage by ensuring simultaneous sintering of metal particles and dielectric material, resolving the contradiction between reduced electrode thickness and maintained coverage.
2Manufacturing precision
If the sintering temperature of metal particles is increased to match the sintering temperature of dielectric layers, then the coverage of inner electrodes increases, but the complexity of the firing process increases
Solution Approach 1:
The patent creates a composite conductive paste by adding a common material (ceramic powder with composition similar to the dielectric layer) to the conventional conductive paste containing metal particles. This composite material approach allows the metal particles to sinter at a higher temperature closer to the dielectric layer sintering temperature, achieving high coverage without requiring separate or complex multi-stage firing processes.
3Device complexity
If conventional conductive paste is used without adding common material, then the firing process is simpler, but the coverage of thin-layer inner electrodes is low
Solution Approach 1:
The patent modifies the compositional parameter of the conductive paste by incorporating a common material (ceramic powder) whose composition is similar to the dielectric layer. This compositional change shifts the sintering behavior of the metal particles, enabling them to sinter at temperatures closer to the dielectric layer sintering temperature, thereby achieving high coverage in thin-layer electrodes while maintaining a relatively simple single-stage firing process.
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
This approach maintains high electrode coverage, thereby ensuring that capacitance is not hindered, even when the electrodes are thin, by aligning the sintering temperatures of the metal particles with those of the dielectric layers.
Implementation Method 1
the temperature at which conductive metal particles included in conductive paste films that are to be the inner electrodes sinter is lower than the temperature at which the ceramic that forms the dielectric layers sinters
Data Source
AI summary
A conductive paste defining inner electrodes of a multilayer ceramic capacitor manufactured through a firing step, includes a conductive metal powder, a ceramic powder, an organic solvent, and an organic binder. At least a portion of the ceramic powder is a powder of at least one oxide of ABO3 type with a specified ionic radius in which a ratio of a six-coordinate ionic radius of an A-site element in ABO3 to a six-coordinate ionic radius of a metal element in the conductive metal powder is about 0.97 or greater and about 1.04 or less. Preferably, when the conductive metal powder includes nickel, the at least one oxide of ABO3 type with the specified ionic radius is at least one of NiTiO3, MgTiO3, or MnTiO3.