Angled Plasma Etching for Variable-Depth Optical Gratings

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Solution Overview

Problem

Conventional methods for forming optical gratings face limitations in flexibility and control over grating parameters, such as depth and angle, which are crucial for precise light manipulation in photonic systems.

Innovation Solution

A method and system using a plasma torch coupled to a scanning tool, enabling both location-specific processing and angle control, allowing for the formation of angled features with variable depths and high material removal rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional methods (holographic lithography, electron beam lithography, interference lithography) are used to form optical gratings, then grating structures can be created, but flexibility and control over grating parameters (depth and angle) are limited

Engineering Contradiction:

Improveflexibility and control over grating parametersVSAvoidcomplexity of setup and process

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent changes the physical state and delivery method of material removal by using plasma processing parameters (power, gas flow, tilt angle) to control grating depth and angle, replacing complex lithographic setups with controllable plasma parameters for flexible grating formation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical lithographic systems (holographic, electron beam, interference lithography) with a plasma-based chemical/physical process that offers superior flexibility in controlling grating parameters through plasma power, gas composition, and substrate orientation

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If electron beam lithography is used to achieve high precision, then grating precision is improved, but processing time increases and productivity decreases

Engineering Contradiction:

Improvegrating precisionVSAvoidprocessing speed

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The patent changes the processing mechanism from slow electron beam scanning to high-speed plasma jet processing, achieving both precision and productivity by controlling plasma parameters (power density, gas flow rate, scan speed) to create accurate gratings rapidly

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses periodic plasma jet scanning across the substrate to form gratings, allowing high-speed processing while maintaining precision through controlled scan patterns and plasma parameter modulation during the scanning process

Inventive Principle:

Principle #19Periodic action

3Area of stationary object

If interference lithography is used to produce large-area gratings, then grating area is improved, but control over variable depth and angle is lost

Engineering Contradiction:

Improvegrating areaVSAvoidcontrol over variable depth and angle

Core Design Contradiction:

Area of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by varying plasma processing parameters (power, gas flow, tilt angle) at different locations and depths during scanning, enabling control over variable depth and angle across large grating areas through localized parameter adjustment during the scan

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces dynamics by making the plasma processing parameters adjustable during the scanning process, allowing real-time modification of power, gas flow, and substrate tilt angle to create variable depth and angle profiles across large grating areas

Inventive Principle:

Principle #15Dynamics

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

Enables the fabrication of optical gratings with customizable profiles for advanced photonic systems, enhancing spectral resolution, diffraction efficiency, and signal-to-noise ratio, and facilitating faster production of specialized components for AR and VR applications.

Implementation Method 1

generating, using the plasma torch, a plasma jet over an area of the substrate holder

Methodology Applied

Scientific EffectPlasma: Plasma

Implementation Method 2

scanning, while maintaining a distance between an end of the plasma nozzle and a surface of the substrate, the substrate relative to the plasma jet to form features on the underlying layer

Methodology Applied

Scientific EffectMaterial removal: Ablation

Data Source

PatentUS20260050110A1Method for angled feature formation

Publication Date: 2026.02.19 TOKYO ELECTRON LTD

AI summary

A method for processing a substrate includes loading the substrate on a substrate holder coupled to a scanning tool and disposed in a processing chamber, the substrate including an etch mask disposed over an underlying layer. The method further includes orienting, using the scanning tool, the substrate holder relative to a plasma torch at a tilt angle, the plasma torch being disposed in the processing chamber and including a plasma nozzle, the tilt angle being an angle between the plasma torch and a normal direction of the substrate holder. And the method further includes generating, using the plasma torch, a plasma jet over an area of the substrate holder, and scanning, while maintaining a distance between an end of the plasma nozzle and a surface of the substrate, the substrate relative to the plasma jet to form features on the underlying layer at the tilt angle.