Internal Electrode Paste Resin Combustion for Ag Diffusion Control
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Solution Overview
Problem
The use of silver (Ag) in internal electrode pastes for multilayer devices can lead to short circuit defects due to Ag diffusion, and existing solutions that attempt to mitigate this issue, such as adding palladium microparticles or adjusting chlorine and sulfur levels, increase the cost.
Innovation Solution
An internal electrode paste comprising Ag as a conductor, a resin that burns completely at a temperature lower than the sintering onset of the conductor, and a water-atomized Ag powder with a sintering onset temperature of 530°C or higher, which generates SO2 and CO2 in minimal amounts, thereby reducing the risk of short circuit defects without increasing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Ag is used as a conductor in internal electrode paste, then electrical conductivity is improved, but short circuit defects occur due to Ag diffusion
Solution Approach 1:
An organic substance is introduced as an intermediary between the Ag particles and the surrounding environment. This organic substance decomposes during firing to form a protective layer that prevents Ag diffusion, thereby eliminating short circuit defects while maintaining the electrical conductivity benefits of Ag.
Solution Approach 2:
The chemical composition and decomposition characteristics of the organic substance are carefully controlled to ensure it decomposes at the appropriate temperature range during firing. By adjusting the parameters of the organic additive (type, amount, decomposition temperature), the protection against Ag diffusion is optimized without compromising electrical conductivity.
2Object-affected harmful factors
If palladium microparticles are added to suppress Ag diffusion, then short circuit defects are reduced, but manufacturing cost increases
Solution Approach 1:
Instead of using expensive palladium microparticles, a cheap organic substance is used that decomposes during the firing process. This disposable organic additive provides the necessary protection against Ag diffusion temporarily during manufacturing, then decomposes to leave no harmful residue, achieving the same protective effect at much lower cost.
Solution Approach 2:
The invention changes the approach from using expensive metal particles to using organic compounds with specific decomposition characteristics. By selecting organic substances that decompose at appropriate temperatures and leave protective residues, the same functional outcome is achieved without the high material cost of palladium.
3Object-affected harmful factors
If chlorine and sulfur impurities are regulated in ferrite sheets, then short circuit defects are suppressed, but manufacturing complexity increases
Solution Approach 1:
Rather than strictly controlling impurity levels in the ferrite sheets, an organic substance is added to the paste as an intermediary that actively prevents Ag diffusion during firing. This shifts the control mechanism from raw material specification to process additive, simplifying the overall manufacturing approach.
Solution Approach 2:
Instead of implementing complex quality control systems to regulate chlorine and sulfur impurities in ferrite sheets, a simple organic additive is used that provides protection during the critical firing stage. This disposable additive approach is much simpler to implement and control than comprehensive impurity regulation systems.
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 proposed internal electrode paste effectively reduces the incidence of short circuit defects while maintaining sinterability and avoiding cost increments, as the resin burns completely below the sintering onset temperature of the conductor, and minimal gas generation further suppresses defect occurrence.
Implementation Method 1
the resin is of a type where 100% of the resin burns in a temperature range that is equal to or lower than a sintering onset temperature of the conductor
Implementation Method 2
the conductor comprises a water-atomized Ag powder that has a sintering onset temperature of 530° C. or higher
Data Source
AI summary
An internal electrode paste including Ag as a conductor, a resin, and a solvent. Wherein the resin is of a type where 100% of the resin burns in a temperature range that is equal to or lower than a sintering onset temperature of the conductor.