Ceramic Capacitor Electrode Wrapping for Low ESL and Adhesion
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Solution Overview
Problem
Ceramic capacitors embedded in substrates face challenges with low adhesion to the substrate, leading to peeling issues and potential short-circuits due to moisture infiltration, and have high equivalent series inductance (ESL) which is not suitable for high-frequency applications.
Innovation Solution
A ceramic capacitor design with specific external and internal electrode configurations, including Cu plated layers, that reduces the distance between electrodes and enhances adhesion to the substrate, thereby minimizing ESL and preventing peeling and short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ceramic capacitor design is used, then manufacturing is simple, but adhesion to substrate is low causing peeling and reliability issues
Solution Approach 1:
The external electrodes extend not only on the principal surfaces but also wrap around the side surfaces of the capacitor main body. This three-dimensional electrode configuration increases the contact area with the substrate in multiple dimensions, significantly improving adhesion strength and preventing peeling while maintaining manufacturing feasibility through standard electrode formation processes.
Solution Approach 2:
The external electrodes are designed to extend beyond the end surfaces of the capacitor main body in advance, creating an overlapping region with the substrate before final assembly. This preliminary extension ensures that the electrodes are already positioned to provide maximum adhesion and electrical connection, preventing subsequent peeling and moisture infiltration.
2Reliability
If conventional capacitor design is used, then structure is simple, but equivalent series inductance (ESL) is high which is not suitable for high-frequency applications
Solution Approach 1:
By extending electrodes onto the side surfaces of the capacitor main body, the current path is shortened in the vertical dimension. This three-dimensional electrode arrangement reduces the loop area and path length for high-frequency currents, thereby reducing equivalent series inductance (ESL) and improving high-frequency performance while maintaining a compact structure.
Solution Approach 2:
The external electrodes are divided into multiple segments that wrap around different surfaces of the capacitor main body. This segmentation allows current to flow through multiple parallel paths, reducing the overall inductance by distributing the current flow and minimizing the magnetic field generated by the current loops.
3Reliability
If multi-terminal capacitors are used to reduce ESL, then ESL is reduced, but embedding in substrate and electrical connection to wirings is difficult
Solution Approach 1:
The external electrodes are designed to serve multiple functions simultaneously: they provide electrical connection to the substrate through extension onto side surfaces, provide mechanical support and adhesion, and enable low-ESL high-frequency performance. This multi-functional design allows the capacitor to be easily embedded in substrates while maintaining reduced ESL, combining the benefits of multi-terminal capacitors with ease of manufacturing.
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 design significantly reduces defective connections and short-circuiting, improves adhesion, and lowers ESL, making the ceramic capacitor suitable for high-frequency applications and embedding in substrates.
Implementation Method 1
A plurality of external electrodes extend from exposed portions of the internal electrodes at the first side surface and exposed portions of the internal electrodes at the second side surface to the first and second principal surfaces. A plurality of external electrodes include a first external electrode, a second external electrode and a third external electrode.
Data Source
AI summary
A ceramic capacitor which is low in ESL and suitable for being built into a substrate has a dimension in a length direction of a lowermost surface of a third external electrode which is in contact with a capacitor main body denoted by e1 and a dimension in the length direction of the uppermost surface of the third external electrode denoted by e2, and a relationship of e1<e2 is satisfied.