Multilayered Ceramic Component Two-Layer Electrode Sealing
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Solution Overview
Problem
Existing multilayered ceramic capacitors face challenges in achieving hermetic sealing and reliable adhesion between internal and external electrodes due to the limitations of glass content in external electrode pastes, which affect Cu wettability, acid resistance, and void filling, leading to issues like glass exudation and poor interface formation.
Innovation Solution
A multilayered ceramic electronic component with a two-layer external electrode structure, where the first layer contains aSiO2-bB2O3-cAEMO glass frit and the second layer contains aSiO2-bB2O3-cAEMO glass frit, along with additional components like Al2O3, TMxOy, and AM2O, optimized in mole percentages to enhance adhesion, corrosion resistance, and Cu wettability, forming a stable Cu—Ni alloy and preventing glass exudation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the silicon oxide content in glass is increased to improve acid resistance, then acid resistance becomes excellent, but Cu wettability is degraded and softening point becomes higher
Solution Approach 1:
The patent changes the chemical composition parameters of the glass frit by specifying precise ranges of SiO2 (30-70 wt%), B2O3 (10-40 wt%), and other oxides, along with controlling the softening point within 700-900°C, to achieve balanced acid resistance and Cu wettability
Solution Approach 2:
The patent uses a composite glass frit system combining multiple oxide components (SiO2, B2O3, Al2O3, CaO, MgO, etc.) where each component contributes specific properties, creating a synergistic effect that resolves the contradiction between acid resistance and wettability
2Object-generated harmful factors
If the silicon oxide content in glass is decreased to improve Cu wettability, then Cu wettability and glass transfer to interface are sufficiently attained, but movement of glass toward interface is too rapid and Cu-Ni alloy is rarely formed
Solution Approach 1:
The patent controls the softening point parameter within 700-900°C and adjusts SiO2 content to 30-70 wt% to regulate the viscosity and flow characteristics of glass during sintering, ensuring controlled movement toward the interface that allows Cu-Ni alloy formation
Solution Approach 2:
The patent creates different glass composition requirements for different regions: the glass frit is designed to have specific composition that enables controlled flow to the Cu-Ni interface region while maintaining appropriate viscosity in the bulk external electrode material
3Ease of manufacture
If a single type of glass is used in Cu paste to simplify manufacturing, then manufacturing process is simple, but it is difficult to satisfy multiple requirements such as adhesiveness, sealing, Cu wettability, and acid resistance
Solution Approach 1:
The patent employs a multi-component glass frit system with specific weight percentage ranges for each oxide component, where the composite structure provides simultaneous adhesion to ceramic, sealing of voids, good Cu wettability, and acid resistance that single-component glass cannot achieve
Solution Approach 2:
The patent designs the glass frit composition to perform multiple functions simultaneously: bonding external electrode to ceramic body, filling and sealing voids, providing acid resistance, and enabling Cu-Ni alloy formation, making the glass material a multi-functional component
4Reliability
If two or three types of glass are used to achieve desired functions, then adhesion and sealing properties improve, but it is difficult to locate the glass at desired position in external electrode due to high temperature characteristics
Solution Approach 1:
The patent controls the softening point parameter within 700-900°C and adjusts the viscosity characteristics of the glass frit to ensure that during the sintering process, the glass flows to the appropriate positions (interface regions) rather than migrating uncontrollably, achieving both proper positioning and desired functions
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 two-layer structure ensures effective hermetic sealing, improved adhesion between electrodes, and enhanced corrosion resistance to plating solutions, reducing glass exudation and contact faults, thereby increasing the reliability and moisture resistance of the ceramic electronic component.
Implementation Method 1
In an external electrode paste, glass may promote copper sintering and, in addition, may serve as an adhesive to combine the external electrode with a ceramic sintered body
Implementation Method 2
fill voids, not charged with Cu, thereby completely sealing the voids
Implementation Method 3
glass with excellent Cu wettability may exhibit low acid-resistance or weak capacity contact
Data Source
AI summary
There is provided a multilayered ceramic electronic component having a reduced thickness and exhibiting hermetic sealing. In multilayered ceramic electronic component, an external electrode includes two layers, that is, first and second layers, and the first and second layers contain glass with different compositions, respectively. Therefore, the multilayered ceramic electronic component having high reliability, such as strong adhesion between the external electrode and the internal electrode, prevention of glass exudation, or the like, may be obtained.