Faraday Cage Plasma Etching for Precise Blazed Pattern Formation

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Solution Overview

Problem

Conventional methods for forming blazed patterns on substrates, such as direct machining and ion beam etching, face challenges in achieving precise structures and desired shapes, while pattern replication using molds is difficult to control.

Innovation Solution

A plasma etching method using a Faraday cage, where a metal mask is applied to the substrate, followed by first plasma etching to form a pattern, and then the substrate is placed in a Faraday cage with a mesh top for inclined etching to create a blazed shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If direct machining method is used to form a pattern, then the structure can be formed on the substrate surface, but it is difficult to achieve precise structural formation

Engineering Contradiction:
Improvepattern structure precisionVSAvoidpattern formation difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces a Faraday cage as an intermediary device between the plasma source and the substrate. The mesh structure of the Faraday cage acts as a mediator that shapes the plasma distribution pattern, enabling precise blazed grating formation without direct mechanical contact or complex masking processes. The cage structure translates electromagnetic field distribution into controlled plasma etching patterns.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces traditional mechanical patterning methods (direct machining or photoresist masking) with a plasma-based approach controlled by electromagnetic fields. The Faraday cage uses electromagnetic field distribution to control plasma generation, substituting mechanical pattern transfer with field-based plasma shaping for higher precision.

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

2Manufacturing precision

If ion beam etching system is used to form a linear sawtooth grating, then a pattern can be formed on the substrate, but it is difficult to form a blazed pattern at a specific position with desired shape

Engineering Contradiction:
Improveblazed pattern shape controlVSAvoidetching system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The Faraday cage is segmented into a mesh structure with specific geometric parameters (mesh size, wire diameter, spacing). This segmentation allows independent control of plasma generation at different spatial locations, enabling precise shaping of blazed gratings at specific substrate positions without requiring complex ion beam scanning systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from traditional planar ion beam etching to a three-dimensional plasma field approach. The Faraday cage creates a spatially distributed plasma field in the vertical dimension above the substrate, allowing blazed pattern formation through field geometry rather than beam angle control, simplifying the system while improving shape control.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If a mold with predetermined blazed pattern is used for pattern replication, then pattern copying can be achieved, but it is difficult for a user to control desired position and shape

Engineering Contradiction:
Improvepattern formation easeVSAvoidpattern position and shape control
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The Faraday cage parameters (mesh size, spacing, geometry) can be dynamically adjusted to control plasma distribution patterns. This dynamic control allows users to easily modify pattern position and shape by changing cage configuration rather than requiring new molds, combining ease of operation with manufacturing precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent uses parameter changes in the Faraday cage structure (mesh dimensions, material composition, spatial arrangement) to control plasma generation characteristics. By adjusting these parameters, users can precisely control blazed pattern formation at desired positions with specific shapes, eliminating the need for physical molds while maintaining ease of pattern formation.

Inventive Principle:
Principle #35Parameter changes

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

This method effectively produces blazed patterns on substrates with high precision and control, enabling efficient formation of blazed shapes and improving etching efficiency.

Implementation Method 1

placing the substrate for etching in a Faraday cage having a mesh portion at the top thereof

Methodology Applied
Scientific EffectFaraday cage electromagnetic shielding: Faraday Cage

Implementation Method 2

enclosure configured to shield an interior of the enclosure from electromagnetic fields exterior to the enclosure

Methodology Applied
Scientific EffectElectromagnetic field shielding: Electromagnetic Induction

Implementation Method 3

performing first plasma etching on the one surface of the substrate for etching to form a first pattern portion

Methodology Applied
Scientific EffectPlasma etching: Plasma

Implementation Method 4

method that uses the ion beam etching system has a problem

Methodology Applied
Scientific EffectIon beam etching: Ion Beam

Implementation Method 5

performing second plasma etching to form the first pattern portion into a second pattern portion having a blazed shape

Methodology Applied
Scientific EffectIon bombardment: Ion Beam

Data Source

PatentEP3819929B1Plasma etching method using faraday box
Publication Date: 2023.12.27 LG CHEM LTD
  • EP3819929B1 patent drawingFigure 1(a)~1(g)
  • EP3819929B1 patent drawingFigure 2
  • EP3819929B1 patent drawingFigure 3

AI summary

The present invention provides a plasma etching method using a Faraday cage, which is capable of effectively producing a pattern portion having a blazed shape.