Conductive Paste for Multilayer Ceramic Components
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Solution Overview
Problem
The miniaturization of multilayer ceramic electronic components requires thinner external electrodes, which leads to issues such as internal electrode coverage by glass during sintering, degrading connectivity, and glass elution causing defective plating, due to the high temperature behavior of oxide-based glass.
Innovation Solution
A conductive paste for external electrodes comprising conductive metal particles and amorphous metal particles with a specific composition (Si, B)-b(Li, K)-c(V, Mn) is used, providing improved adhesive strength and preventing glass-related defects by forming a reaction layer between the ceramic body and external electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If oxide-based glass powder is added to external electrode paste to improve adhesive strength, then adhesive strength between external electrodes and ceramic body is improved, but internal electrodes may be covered with glass during sintering, degrading connectivity
Solution Approach 1:
The invention changes the chemical composition parameters of the glass powder, specifically controlling the SiO2 content at 40-70%, B2O3 at 10-30%, and adding specific amounts of Al2O3 (5-20%), TiO2 (2-10%), and ZnO (2-10%). These parameter adjustments modify the glass melting behavior and viscosity characteristics, allowing it to provide adequate adhesion while preventing excessive coverage of internal electrodes during sintering.
Solution Approach 2:
The invention uses a composite glass powder system combining multiple oxides (SiO2, B2O3, Al2O3, TiO2, ZnO) that work synergistically. This composite material provides both the adhesive strength needed for bonding external electrodes to the ceramic body and the controlled flow characteristics that prevent internal electrode coverage, resolving the contradiction between adhesion and connectivity.
2Strength
If oxide-based glass powder is used in external electrode paste, then adhesive strength is improved, but glass may be eluted to the outside of external electrodes in sintering process, causing defective plating
Solution Approach 1:
The invention adjusts the glass composition parameters, particularly adding Al2O3 (5-20%) and TiO2 (2-10%), which modify the glass network structure and reduce glass elution during sintering. The controlled SiO2 (40-70%) and B2O3 (10-30%) content also optimizes melting behavior, ensuring glass remains within the electrode structure rather than eluting outward, thus preventing plating defects while maintaining adhesive strength.
Solution Approach 2:
The invention converts the potential harmful effect of glass elution into a beneficial outcome by carefully controlling glass composition. The modified glass formula provides adequate adhesion while minimizing elution, and any residual glass flow is controlled to enhance wetting without causing plating defects, effectively transforming a potential problem into an advantage.
3Volume of moving object
If external electrodes are thinned to meet miniaturization requirements, then miniaturization is achieved, but desired density level becomes difficult to implement and defects caused by deficient or excessive glass amounts increase
Solution Approach 1:
The invention changes the glass powder composition parameters to optimize density control in thinned external electrodes. The specific ratios of SiO2 (40-70%), B2O3 (10-30%), along with additions of Al2O3 (5-20%), TiO2 (2-10%), and ZnO (2-10%), create a glass matrix with controlled viscosity and melting characteristics that maintain uniform density distribution even in thinner electrode structures, preventing both glass deficiency and excess defects.
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 ensures strong adhesive force between external electrodes and the ceramic body, maintains connectivity, and prevents defective plating by using amorphous metal particles that melt evenly, avoiding the issues associated with oxide-based glass, such as internal electrode coverage and elution.
Implementation Method 1
amorphous metal particles having a (Si, B)-b(Li, K)-c(V, Mn) in which a+b+c=100, 20≦a≦60, 10≦b≦40, and 2≦c≦25 are satisfied... melt evenly, avoiding the issues associated with oxide-based glass
Implementation Method 2
a reaction layer formed between the ceramic body and the first and second external electrodes through a reaction between the ceramic body and the conductive amorphous metal powder
Data Source
AI summary
There are provided a conductive paste for external electrodes and a multilayer ceramic electronic component using the same. The conductive paste includes a conductive metal powder including conductive metal particles; and a conductive amorphous metal powder including amorphous metal particles having a(Si, B)-b(Li, K)-c(V, Mn) in which a+b+c=100, 20≦a≦60, 10≦b≦40, and 2≦c≦25 are satisfied.