Ceramic Capacitor External Electrodes Sputtering Copper Embedding
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Solution Overview
Problem
Existing ceramic capacitors are not suitable for embedding in substrates due to high equivalent series inductance (ESL) and poor electrical connection with via hole electrodes, leading to potential defective connections and reduced reliability.
Innovation Solution
A ceramic capacitor design with sputtering electrode films and Cu plated layers, where external electrodes are thinned and extended to improve flatness and electrical connection, reducing ESL by minimizing current path length and enhancing adhesion to substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fired electrodes are formed by roller coating method, then external electrodes can be formed on ceramic base body, but conductive paste runs on principal surface causing non-uniform thickness and poor flatness
Solution Approach 1:
The patent introduces a barrier layer (insulating film) as an intermediary between the conductive paste and the principal surface of the ceramic base body. This barrier layer prevents the conductive paste from running onto the principal surface during the coating process, thereby maintaining uniform thickness and good flatness of the external electrodes while still allowing the roller coating method to be used effectively.
2Reliability
If multi-terminal capacitor is used to reduce ESL, then equivalent series inductance decreases, but embedding in substrate and electrical connection to wirings becomes difficult
Solution Approach 1:
The patent transitions from conventional top-surface mounting to three-dimensional embedding by extending internal electrodes to the side surfaces of the ceramic base body. This allows the capacitor to be vertically embedded in the substrate with external electrodes formed on the side surfaces, achieving both low ESL through multi-terminal configuration and good adaptability for substrate integration.
3Reliability
If external electrodes are extended over principal surfaces, then electrical connection to via hole electrodes is improved, but flatness is impaired and defective connection may occur
Solution Approach 1:
The patent uses a barrier layer (insulating film) as a mediator to control the extension of external electrodes. The barrier layer allows external electrodes to extend to the side surfaces for good electrical connection while preventing them from running uncontrollably on the principal surface, thereby maintaining flatness and preventing defective connections.
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 results in a ceramic capacitor with reduced ESL, improved electrical connection, and increased reliability for embedding in substrates, preventing defective connections and enhancing capacitance while maintaining component size.
Implementation Method 1
Each of the outermost layers of the first, second and third external electrodes contains Cu... each external electrode includes a sputtering electrode film
Implementation Method 2
Each of the outermost layers of the first, second and third external electrodes contains Cu
Data Source
AI summary
A ceramic capacitor which is low in ESL and suitable for being built into a substrate includes a first external electrode, a second external electrode and a third external electrode. Each of the first, second and third external electrodes include a sputtering electrode film. Each of the outermost layers of the first, second and third external electrodes contains Cu.