Capacitor with Cu-plated Side Electrodes for Low ESL
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Solution Overview
Problem
Existing capacitors are not suitable for incorporation into substrates due to high equivalent series inductance (ESL) and inadequate contact properties with wirings, which hinders their integration and reliability.
Innovation Solution
A capacitor design with a Cu-plated outer electrode that facilitates easy incorporation into substrates by reflecting laser light during via hole formation, and a structured outer electrode configuration that protects ridge line portions and enhances contact force, reducing the risk of damage and water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a capacitor is designed with conventional electrode structure, then the basic capacitance function is achieved, but the equivalent series inductance (ESL) is high and contact property with wirings is inadequate
Solution Approach 1:
The patent transitions from conventional top-bottom electrode arrangement to a side-surface exposed electrode configuration. The outer electrode is designed to extend along the side surface of the capacitor main body, exposing the inner electrode at the side surface rather than only at the top and bottom surfaces. This dimensional change in electrode arrangement reduces the current path length and inductance, while providing better contact surfaces for wiring connection on the substrate.
Solution Approach 2:
The outer electrode is divided into multiple segments: a first outer electrode covering the first side surface, a second outer electrode covering the second side surface, and a third outer electrode covering the third side surface. This segmentation allows each electrode segment to independently contact separate wiring regions on the substrate, improving overall contact property and reducing equivalent series inductance through parallel current paths.
2Ease of manufacture
If the capacitor is incorporated into a substrate using laser drilling, then via holes are formed for electrical connection, but the outer electrode deteriorates due to laser exposure
Solution Approach 1:
The patent introduces an intermediary protective layer between the outer electrode and the laser beam. This protective layer, positioned on the outer electrode surface, absorbs or reflects the laser energy during via hole formation, preventing direct laser exposure to the outer electrode material and thus avoiding electrode deterioration while still allowing the manufacturing process to proceed.
3Object-affected harmful factors
If the capacitor main body is exposed without outer electrode coverage, then water ingress is prevented through better sealing, but external stress damages the ridge line portions
Solution Approach 1:
The patent applies different protective qualities to different regions of the capacitor. The outer electrode is designed to extend along and cover the ridge line portions where stress concentration occurs, providing localized mechanical protection. Meanwhile, the sealing structure is optimized in other regions to prevent water ingress, achieving both protection goals through region-specific design.
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 capacitor design effectively reduces ESL, improves reliability by preventing damage from external stress and water ingress, and ensures reliable electrical connections with substrates.
Implementation Method 1
the outermost layer of the outer electrode includes a Cu-plated layer... laser light that is emitted for forming the via hole is reflected by the outer electrode with high reflectance
Data Source
AI summary
A capacitor includes an outer electrode extends over first and second main surfaces from exposed portions of inner electrodes on a first side surface and exposed portions of the inner electrodes on a second side surface. An outermost layer of the outer electrode includes a Cu-plated layer.