Thin-Film Capacitor Groove Structure for Same-Plane Electrodes
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Solution Overview
Problem
Existing thin film capacitors face issues with increased ESR and ESL due to long electrode line lengths and complex structures, and are prone to short circuits and peeling, especially when embedded in circuit boards.
Innovation Solution
A thin film capacitor design featuring a metal foil with a non-roughened center portion and a roughened surface, incorporating a groove that exposes the center portion, and an insulating member to enhance adhesion and reduce electrode length, along with a dielectric film for increased capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a side surface electrode structure is used, then the electrode can be formed, but the line length of the electrode becomes long, increasing ESR and ESL
Solution Approach 1:
The patent transitions from a side surface electrode structure to a planar electrode structure where both terminal electrodes are disposed on the same plane. This dimensional reconfiguration shortens the electrode line length by eliminating the need for electrodes to traverse the side surface, directly reducing ESR and ESL while maintaining electrical functionality.
Solution Approach 2:
The patent extracts and removes the support structure from the capacitor design. By eliminating the support, the electrode line length is further reduced, and ESR and ESL are minimized. The capacitor achieves structural integrity through alternative means without requiring a separate support component.
2Reliability
If a porous metal substrate is used, then the capacitor can be formed, but it is not easy to separate the lower electrode and upper electrode, likely causing short circuit failure
Solution Approach 1:
The patent applies local quality by creating a non-roughened center portion in the metal foil while maintaining roughened surfaces in other areas. This localized modification provides a smooth, easily separable region in the center that facilitates electrode separation and prevents short circuits, while the roughened portions maintain adequate adhesion where needed.
3Ease of operation
If terminal electrodes are disposed on both surfaces of a metal substrate, then the capacitor can be formed, but access to the terminal electrode pair from one side is hindered
Solution Approach 1:
The patent reconfigures the electrode arrangement from a vertical distribution (both surfaces) to a horizontal arrangement (same plane). Both terminal electrodes are now accessible from the same side of the capacitor, enabling single-sided access and simplifying mounting and electrical connection processes.
4Reliability
If the entire metal substrate is made porous, then the capacitor can be formed, but adhesion is insufficient, causing peeling and void generation
Solution Approach 1:
The patent creates different surface characteristics in different regions of the metal foil. The roughened surfaces provide enhanced adhesion and prevent peeling in areas where electrical connection is needed, while the non-roughened center portion provides a stable, void-free region for insulating member contact, achieving both adhesion strength and compositional stability.
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 allows for terminal electrodes to be disposed on the same plane, reducing ESR and ESL, enhancing adhesion, and minimizing peeling and void generation, thus improving performance and reliability.
Implementation Method 1
a metal foil having a non-roughened center portion and a roughened surface
Implementation Method 2
a dielectric film covering the roughened surface of the metal foil
Data Source
AI summary
To provide a thin film capacitor having a pair of terminal electrodes capable of being disposed on the same plane. A thin film capacitor includes: a metal foil having a non-roughened center portion and a roughened upper surface; a dielectric film covering the roughened upper surface of the metal foil; an electrode layer contacting the metal foil; an electrode layer contacting the dielectric film without contacting the metal foil; and an insulating member positioned between the electrode layers and. The metal foil has a groove formed so as to penetrate a roughened surface layer of the metal foil and exposing therethrough the non-roughened center portion. The insulating member contacts the center portion of the metal foil that is exposed to the bottom of the groove.