Multielectrode Extraction Assembly for Parallel Sidewall Angled Etching
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Solution Overview
Problem
Existing substrate processing technologies face challenges in generating angled structures with controlled sidewall geometry, particularly in forming optical gratings, as the radical flux vectors often do not match the ion flux vectors, leading to non-parallel sidewalls.
Innovation Solution
A multielectrode extraction assembly is used in a plasma source to generate angled ions and radicals that impinge on the substrate at a non-zero angle, ensuring co-linear flux with similar angle spreads, allowing for tightly controlled angled etching of trenches, lines, or holes with parallel sidewalls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional plasma etching is used, then substrate processing is achieved, but sidewall parallelism and angle control deteriorate due to mismatched radical and ion flux vectors
Solution Approach 1:
The extraction assembly is segmented into multiple independently controllable electrodes (first electrode, second electrode, third electrode) with separate apertures. Each electrode can be independently biased to control the extraction of ions and radicals, allowing independent optimization of their flux vectors to achieve parallel sidewalls while maintaining manageable device complexity through modular electrode design
Solution Approach 2:
Different regions of the extraction assembly are assigned different functions: the first electrode aperture extracts ions, the second electrode aperture extracts radicals, and the third electrode provides additional control. This local differentiation of electrode functions enables precise control over flux vector alignment at specific locations, achieving parallel sidewalls without requiring complete redesign of the entire etching system
2Manufacturing precision
If angled etching is performed to form optical gratings, then grating properties are improved, but control over etching angle and sidewall geometry deteriorates
Solution Approach 1:
The extraction assembly enables dynamic control of ion and radical extraction by independently adjusting the bias voltage on each electrode. This dynamic control allows real-time adjustment of flux ratios and angles during the etching process, maintaining ease of operation through programmable voltage control while achieving precise angle control for optical grating formation
Solution Approach 2:
The system changes multiple parameters simultaneously - extraction voltage, flux ratio, and angle of incidence - by independently controlling each electrode's bias. This multi-parameter control capability enables precise tuning of etching geometry for optical gratings while maintaining ease of operation through automated parameter adjustment based on process requirements
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 approach enables superior control over grating properties by ensuring parallel sidewalls in etched structures, improving the optical properties of optical gratings and allowing for the formation of angled features with precise geometry.
Implementation Method 1
generating a plasma in a plasma chamber, adjacent to the substrate
Implementation Method 2
an angled ion beam may be extracted from the extraction assembly, the angled ion beam defining a non-zero angle of incidence with respect to the substrate plane, wherein the angled ion beam etches the grating layer
Data Source
AI summary
A plasma source may include a plasma chamber, where the plasma chamber has a first side, defining a first plane and an extraction assembly, disposed adjacent to the side of the plasma chamber, where the extraction assembly includes at least two electrodes. A first electrode may be disposed immediately adjacent the side of the plasma chamber, wherein a second electrode defines a vertical displacement from the first electrode along a first direction, perpendicular to the first plane, wherein the first electrode comprises a first aperture, and the second electrode comprises a second aperture. The first aperture may define a lateral displacement from the second aperture along a second direction, parallel to the first plane, wherein the vertical displacement and the lateral displacement define a non-zero angle of inclination with respect to a perpendicular to the first plane.