Multilayer Ceramic Capacitor Curved Electrode Sintering Separation
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Solution Overview
Problem
In multilayer ceramic capacitors, the separation between the shared internal electrode layer and the dielectric layer on the low-capacitance part side adjoining the shared internal electrode layer occurs due to the thickness difference between the dielectric layers of the high-capacitance and low-capacitance parts during the sintering process.
Innovation Solution
The capacitor design includes a shared internal electrode layer with a curved part projecting towards the dielectric layer on the low-capacitance part side, ensuring a greater thickness of dielectric layers on the high-capacitance part side in at least two locations, which reduces the likelihood of separation between the internal electrode layer and the dielectric layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the thickness of dielectric layers on the high-capacitance part side is made greater than the thickness of dielectric layers on the low-capacitance part side, then the capacitance of the high-capacitance part increases, but separation occurs between the shared internal electrode layer and the dielectric layer on the low-capacitance part side during sintering
Solution Approach 1:
The shared internal electrode layer is designed with a curved cross-sectional shape that projects toward the dielectric layer on the low-capacitance part side. This curvature creates a geometric interlocking effect where the protruding portions of the electrode layer mechanically anchor the dielectric layer, preventing separation during sintering while maintaining the thickness difference needed for capacitance differentiation.
Solution Approach 2:
The patent introduces asymmetry in the shape of the shared internal electrode layer, making it non-uniform across its width. The electrode layer has different thicknesses at different locations, with protruding portions toward the low-capacitance part side and thinner portions toward the high-capacitance part side. This asymmetric design allows the electrode to mechanically interlock with dielectric layers on both sides while maintaining the required capacitance difference.
2Quantity of substance
If the thickness of dielectric layers on the high-capacitance part side is made greater than the thickness of dielectric layers on the low-capacitance part side, then the capacitance relationship (Capacitance of high-capacitance part > Capacitance of low-capacitance part) is satisfied, but the shared internal electrode layer and dielectric layer on the low-capacitance part side separate during sintering
Solution Approach 1:
The curved cross-sectional shape of the shared internal electrode layer creates physical interlocking features that maintain precise alignment between layers during the sintering process. The protruding portions act as mechanical stops that prevent lateral displacement and separation, ensuring manufacturing precision is maintained despite the thickness difference between high-capacitance and low-capacitance parts.
3Ease of manufacture
If a flat shared internal electrode layer is used, then the manufacturing process is simpler, but separation occurs between the shared internal electrode layer and the dielectric layer on the low-capacitance part side during sintering
Solution Approach 1:
While maintaining relative manufacturing simplicity, the patent introduces curvature only to the shared internal electrode layer that is adjacent to dielectric layers of different thicknesses. This localized curving creates mechanical interlocking features during a relatively simple lamination process, preventing separation during sintering without requiring complex manufacturing steps for all electrode layers.
Solution Approach 2:
The patent applies the curved shape feature specifically to the shared internal electrode layer that interfaces dielectric layers of different thicknesses, while other internal electrode layers can maintain simpler flat shapes. This localized application of complexity only where needed maintains ease of manufacture for the overall device while solving the bonding reliability issue at the critical interface.
Data Source
AI summary
In an embodiment, a multilayer ceramic capacitor 10 is constituted in such a way that its capacitor body 11 houses a capacitance part which is halved in the third direction d3, along a shared internal electrode layer 11a3 serving as a boundary, into a high-capacitance part HC and a low-capacitance part LC. When the capacitor body 11 is cut along a surface crossing at right angles with the first direction d1, the revealed cross-sectional shape of the shared internal electrode layer 11a3 has a cross-sectional shape where a curved part CP that projects toward the dielectric layer 11b2 on low-capacitance part LC side adjoining the shared internal electrode layer 11a3, is present on both sides in the second direction d2, and also in between.