Ultra-Compact Microcapacitor Using Rolled-Up Layer Stack
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Solution Overview
Problem
Existing methods for producing rolled-up capacitors are time-consuming, require hazardous chemicals, and result in large installation areas and insufficient capacitance, limiting the miniaturization of electronic devices.
Innovation Solution
A method involving a rolled-up layer stack of alternating dielectric and conductive materials, using a water-soluble cellulose derivative or polymer as a sacrificial layer, which is removed with water or a solvent, allowing for high rolling speeds and compact capacitor design without the need for corrosive etchants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional etching methods with sacrificial layers are used to produce rolled-up capacitors, then the capacitor structure can be formed, but the production time becomes excessively long and corrosive chemicals are required
Solution Approach 1:
The patent changes the chemical parameter of the sacrificial layer from materials requiring long etching times (such as germanium) to water-soluble materials (such as cellulose derivatives and polymers). This parameter change enables rapid removal of the sacrificial layer through simple water washing, reducing production time from hours to minutes while eliminating the need for corrosive etchants like hydrogen peroxide
Solution Approach 2:
The patent employs water-soluble sacrificial layers that are easily disposable and can be rapidly removed by water washing. These sacrificial layers serve their temporary purpose of defining the capacitor structure during manufacturing and are then completely removed without requiring complex recovery processes, enabling fast production cycles
2Area of stationary object
If the capacitor installation area is reduced to achieve miniaturization, then the device compactness improves, but the electrical capacitance becomes insufficient
Solution Approach 1:
The patent transitions from planar capacitor structures to three-dimensional rolled-up configurations. By winding the layer stack into a cylindrical or spiral form, the effective capacitor area is multiplied while occupying minimal footprint space on the substrate, enabling high capacitance values (at least 10 nF, preferably 50 nF to 1 μF) within ultra-compact installation areas
Solution Approach 2:
The patent implements a nested structure where multiple alternating layers of conductive and dielectric materials are rolled up concentrically. The inner layers are nested within outer layers, creating a compact cylindrical capacitor where each layer contributes to the total capacitance, achieving high electrical storage capacity in a minimal volume
3Reliability
If the sacrificial layer removal time is extended to achieve complete undercutting, then the layer separation improves, but the corrosive effect on metal layers increases
Solution Approach 1:
The patent uses water as a benign intermediary substance to remove the water-soluble sacrificial layer. This intermediary enables complete layer separation and undercutting without introducing corrosive chemicals that would damage the metal conductive layers, achieving reliable capacitor structure formation while preserving material integrity
Solution Approach 2:
The patent converts the previously harmful effect of requiring long etching times into a benefit by using water-soluble sacrificial materials. The water solubility, which could be seen as a limitation for structural stability during processing, actually enables rapid and complete removal without corrosion, turning a potential weakness into a manufacturing advantage
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 method enables the production of ultra-compact microcapacitors with high capacitance and small installation area, achieved through a cost-effective, environmentally friendly, and time-saving process, with rolling-up speeds exceeding 0.1 mm/min and storage capacities of at least 50 nF.
Implementation Method 1
A hydrogel can also be used as a lower part of the layer structure, which hydrogel is placed in contact with water, thereby absorbs the water, swells up, and causes the rolling-up of the layer stack
Data Source
AI summary
The present invention relates to the area of micro- and nanoelectronics and relates to ultra-compact micro capacitors, how they can be used, for example, in electrical and electronic devices. The object of the present invention consists in specifying an ultra-compact micro capacitor with the highest capacity. The problem is solved by an ultra-compact micro capacitor which is made from a rolled-up layer stack of alternatingly arranged layers of dielectric and/or electrically insulating and electrically conductive materials with rolled-up lengths of the layer stack of at least 1 mm, and an absolute electrical storage capacity of at least 10 nF. The problem is additionally solved by a method, in which a layer containing a water-soluble cellulose derivative is applied to a substrate and a layer stack to same, the layer containing the cellulose derivative is removed from the substrate using water, an organic solvent and/or an organic solvent mixture, and the layer stack is rolled up with a rolling speed of more than 0.1 mm/min.