Capacitor Structure with Comb-Shaped Electrodes for High Density
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Solution Overview
Problem
Existing capacitor manufacturing techniques face challenges in increasing capacitance density and aspect ratio in the z-direction, leading to limitations in compact, high-capacitance designs, and require complex processes that include etching and thermal shrinkage, which also result in high ESL (Equivalent Series Inductance).
Innovation Solution
A capacitor design featuring anodic metal oxide dielectric material with comb-shaped surface electrodes and pillar-shaped internal electrodes, where the surface electrodes are formed alternately and in parallel, and internal electrodes extend through the dielectric material, along with a manufacturing method that includes anodic oxidation and seed layer formation to simplify the process and reduce ESL.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electrode is formed by etching metal film on substrate, then manufacturing process is simplified, but aspect ratio in z direction cannot be increased
Solution Approach 1:
The patent replaces the mechanical etching process with an electrochemical anodization process to form the dielectric layer. This substitution enables the formation of high aspect ratio porous structures that cannot be achieved through conventional etching, while maintaining manufacturing feasibility through a single-step self-organizing process.
Solution Approach 2:
The patent utilizes the phase transition and self-organization properties of anodization to form highly ordered porous dielectric structures. The anodization process transforms the metal substrate into a porous oxide layer with controlled morphology, enabling high aspect ratio electrode formation without complex etching steps.
2Quantity of substance
If capacitance is increased by increasing electrode area, then capacitance density improves, but device size increases
Solution Approach 1:
The patent transitions from planar electrode geometry to three-dimensional porous columnar structures. By utilizing the vertical dimension and creating high aspect ratio pillars, the electrode surface area is dramatically increased within a compact footprint, achieving high capacitance density without proportionally increasing device volume.
Solution Approach 2:
The patent employs porous anodic oxide structures as the dielectric layer, which provides extremely high surface area to volume ratio. The porous morphology enables significant capacitance enhancement within a compact structure by increasing the effective electrode area through the porous network rather than expanding the overall device dimensions.
3Reliability
If complex manufacturing process with burning step is used, then dielectric layer can be formed, but thermal shrinkage occurs between electrode and dielectric member
Solution Approach 1:
The patent replaces the thermal burning process with an electrochemical anodization process. This substitution eliminates the high-temperature thermal cycles that cause differential thermal expansion and shrinkage, while still achieving complete dielectric layer formation through controlled electrochemical oxidation at lower temperatures.
Solution Approach 2:
The patent introduces an electrolyte solution as an intermediary medium to facilitate dielectric layer formation through anodization. The electrolyte enables controlled electrochemical oxidation at moderate temperatures, avoiding the direct thermal processing that causes thermal mismatch and shrinkage between different materials.
4Ease of manufacture
If conventional capacitor structure is used, then manufacturing is straightforward, but ESL (Equivalent Series Inductance) is high
Solution Approach 1:
The patent segments the electrode structure into multiple interleaved comb-shaped electrodes rather than using conventional parallel plate geometry. This segmentation creates multiple current paths and reduces the loop area for high-frequency current flow, thereby reducing equivalent series inductance while maintaining manufacturing feasibility through patterned deposition.
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 enhances capacitance density by increasing the area determining capacitance and reduces ESL through opposite current directions of internal electrodes, simplifying the manufacturing process and achieving a high aspect ratio for internal electrodes.
Implementation Method 1
a first step of forming a pair of substantially comb-shaped recess patterns on a principal surface of a metal base material... a second step of anodically oxidizing the metal base material to form a dielectric material having plural pores
Data Source
AI summary
A capacitor includes a dielectric material that is formed of anodic metal oxide; a pair of substantially comb-shaped surface electrodes formed on the same principal surface of the dielectric material; and plural substantially columnar internal electrodes whose one ends are connected to the respective comb-shaped portions of the pair of the surface electrodes and whose other ends extend in the thickness direction of the dielectric material.