Cylindrical RIE for Nanostructured Surfaces

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Solution Overview

Problem

Existing methods for creating subwavelength nanostructured surfaces are complex and expensive, limiting their commercial viability due to the need for extreme vacuum conditions and batch processes.

Innovation Solution

A continuous roll-to-roll process using cylindrical reactive ion etching (RIE) at moderate vacuum conditions to produce anisotropic nanostructured surfaces, reducing reflection and enhancing durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If extreme vacuum conditions are used to create subwavelength surface structure, then nanostructured surfaces can be produced, but the process becomes expensive and commercially unviable

Engineering Contradiction:
Improvesubwavelength surface structureVSAvoidcommercial viability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent changes the vacuum pressure parameter from extreme vacuum (<0.5 mTorr) to moderate vacuum (5-10 mTorr), making the process commercially viable while still achieving subwavelength surface structures through plasma treatment

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical vacuum system requirement with a plasma-based chemical etching process that works at moderate vacuum levels, substituting extreme mechanical vacuum conditions with controlled plasma chemistry

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If batch processes are used to create nanostructured surfaces, then subwavelength structures can be produced, but the process becomes complicated and time-consuming

Engineering Contradiction:
Improvesubwavelength surface structureVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent implements a continuous roll-to-roll plasma treatment process where substrates move continuously through the plasma zone, eliminating batch processing steps and reducing overall process complexity while maintaining subwavelength structure quality

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If isotropic etching is used to create subwavelength surface structure, then nanostructures can be produced, but additional coating is required to provide durability

Engineering Contradiction:
Improvesubwavelength surface structureVSAvoiddurability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent inverts the approach by using anisotropic etching instead of isotropic etching, creating directional nanostructures that inherently provide durability without requiring additional protective coatings

Inventive Principle:
Principle #13The other way round (Inversion)

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 achieves significant reduction in surface reflectance and provides durable, scratch-resistant nanostructured articles in a cost-effective and simplified manner.

Implementation Method 1

Gas comprising an etchant is fed into the vacuum vessel, and plasma is ignited and sustained between the drum electrode and the grounded counter-electrode

Methodology Applied
Scientific EffectPlasma: Plasma

Implementation Method 2

cylindrical reactive ion etching (cylindrical RIE) to produce anisotropic nanostructured surfaces

Methodology Applied
Scientific EffectReactive ion etching:

Data Source

PatentEP3115334B1Method for making nanostructured surfaces using a microstructured surface and a nanoscale mask
Publication Date: 2018.03.21 3M INNOVATIVE PROPERTIES CO
  • EP3115334B1 patent drawingFigure 1
  • EP3115334B1 patent drawingFigure 2
  • EP3115334B1 patent drawingFigure 3~4

AI summary

The present invention related to a continuous method for making a nanostructured surface comprising: (a) placing a substrate which comprises a microstrctured surface and a nanoscale mask on a cylindrical electrode in a vacuum vessel, (b) introducing etchant gas to the vessel at a predetermined pressure, (c) generating plasma between the cylindrical electrode and a counterelectrode, (d) rotating the cylindrical electrode to translate the substrate, and (e) anisotropically etching a surface of the substrate to provide anisotropic nanoscale features on the surface.