MLCC Bonding Units with High Silicon Content
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Solution Overview
Problem
The existing methods for producing multi-layer ceramic capacitors face challenges in ensuring uniform thickness of side margins, leading to insulation property issues and increased risk of cracks and peel-off during high-temperature and moisture-resistance tests due to differences in shrinkage behavior between the multi-layer chip and side margins.
Innovation Solution
Incorporating bonding units with higher silicon content between the multi-layer unit and side margins, which generate molten phases at sintering to reduce shrinkage differences and enhance bonding, while maintaining a thickness of 0.5 μm or more but no greater than 5 μm to minimize form and performance impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If side margins are made thinner to enlarge internal electrodes, then capacitance increases, but insulation properties deteriorate
Solution Approach 1:
A low melting point glass layer is introduced as an intermediary substance between the internal electrode and the side margin. This glass layer has a melting point lower than both the internal electrode material and the side margin material, allowing it to soften during sintering and create a bonding bridge that ensures insulation properties even when side margins are thin.
Solution Approach 2:
The invention changes the thermal parameter (melting point) of the bonding interface by introducing a glass material with specifically controlled melting characteristics. The glass layer's melting point is positioned between those of the internal electrode and side margin, enabling it to undergo phase change at sintering temperature and facilitate bonding while maintaining insulation.
2Strength
If side margins are attached with strong pressing force to ensure bonding, then bonding strength increases, but ceramic layers peel off from one another
Solution Approach 1:
The low melting point glass layer is applied in advance to the side surfaces of the multi-layer chip before the final pressing operation. During subsequent sintering, this pre-applied glass layer softens and acts as a buffering medium that distributes pressing forces, preventing direct transmission of strong pressing forces that would cause layer peeling while still ensuring adequate bonding.
Solution Approach 2:
The glass layer undergoes phase transition from solid to liquid state at its melting point during sintering. This phase transition allows the glass to flow and conform to the surfaces it contacts, creating strong bonding without requiring high pressing forces, thereby preventing ceramic layer peeling while ensuring adequate bonding strength.
3Stability of the object's composition
If side margins are attached without strong pressing force to prevent peeling, then layer integrity is maintained, but bonding properties deteriorate
Solution Approach 1:
The glass layer's phase transition from solid to liquid during sintering enables it to flow and wet the contacting surfaces, creating strong bonding interfaces. This thermal softening mechanism allows adequate bonding to be achieved without requiring strong pressing forces during assembly, thereby maintaining layer integrity.
Solution Approach 2:
The invention changes the physical state and viscosity parameters of the glass layer through temperature control during sintering. By heating to the glass's melting point, the material transitions to a low-viscosity state that enables spontaneous flow and bonding, achieving strong adhesion without mechanical pressing that could damage the layered structure.
4Manufacturing precision
If density of side margins is increased to match multi-layer chip, then shrinkage behavior uniformity improves, but manufacturing complexity increases
Solution Approach 1:
Instead of changing the density parameter of the side margins to match the multi-layer chip, the invention changes the thermal and compositional parameters of the glass layer. The glass composition is formulated with specific low melting point components that enable it to undergo controlled phase change during sintering, compensating for density differences and achieving uniform shrinkage behavior without complex manufacturing processes.
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 configuration achieves high bonding properties between the multi-layer unit and side margins, preventing cracks and ensuring reliability by matching shrinkage behaviors and maintaining capacitance performance.
Implementation Method 1
molten phases containing silicon are generated at the sintering in the bonding units having high silicon content, and thus the bonding units are softened
Implementation Method 2
at the sintering in the bonding units having high silicon content
Data Source
AI summary
A multi-layer ceramic capacitor includes a multi-layer unit, side margins, and bonding units. The multi-layer unit includes ceramic layers laminated in a first direction and internal electrodes disposed between the ceramic layers. The side margins cover the multi-layer unit from a second direction orthogonal to the first direction. The bonding units are each disposed between the multi-layer unit and each of the side margins and have higher silicon content than the ceramic layers and the side margins.