Polarized Laser-Assisted Plasma Etching for Nanoscale Trenches
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Solution Overview
Problem
Current etching methods, such as reactive ion etching, cause surface damage and material mixing due to high-energy ions, which is detrimental for semiconductor devices with feature sizes of 100 nm or less, and fail to achieve damage-free, anisotropic etching.
Innovation Solution
Laser-assisted plasma etching using polarized light is employed to etch trenches on semiconductor substrates, where the trenches are exposed to a plasma and simultaneously illuminated with a pulsed laser beam having a predetermined polarization, allowing for selective etching of base or upper regions without damaging the surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If reactive ion etching is used to achieve anisotropic etching, then etching directionality is improved, but surface damage and material mixing occur
Solution Approach 1:
The patent introduces a resistive heating intermediary mechanism where laser-induced heating of the trench structures modifies the plasma etching process. The heating acts as a mediator that enables selective etching without direct high-energy ion damage to the surface, resolving the contradiction between anisotropic etching capability and surface integrity
Solution Approach 2:
The patent changes the physical state and energy distribution parameters by introducing laser heating. This transforms the etching process from a purely cold plasma process to a thermally-assisted plasma process, where temperature gradients enable selective etching while preventing surface damage from ion bombardment
2Productivity
If high energy ions are used for material removal, then etching speed is improved, but surface fidelity deteriorates
Solution Approach 1:
The patent converts the harmful effect of plasma exposure into a beneficial resistive heating effect. The same plasma that causes damage through ion bombardment is harnessed to generate localized heating in the trench structures, which then enables selective etching while protecting the surface from ion damage
Solution Approach 2:
The patent substitutes the mechanical sputtering action of high-energy ions with a thermally-driven etching mechanism. Instead of relying on ion momentum transfer for material removal, the process uses laser-induced heating to create temperature gradients that drive selective etching, thereby preserving surface fidelity
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 enables the fabrication of semiconductor devices with smaller feature sizes by achieving anisotropic etching without surface damage, as demonstrated by computer simulations and experimental results showing controlled etching of trenches with nanoscale features.
Implementation Method 1
The trenches are etched by exposing the surface to a plasma and simultaneously illuminating the surface with a pulsed laser beam having a predetermined polarization
Implementation Method 2
computer simulations and experimental results showing controlled etching of trenches with nanoscale features
Implementation Method 3
The trenches are etched by exposing the surface to a plasma
Data Source
AI summary
A method of laser-assisted plasma etching with polarized light comprises providing a surface of a substrate that includes at least one surface region having trenches arranged in a unidirectional pattern along an x-direction or a y-direction of the surface, where each trench has a depth along a z-direction. The trenches extend substantially in parallel with each other and have a half-pitch of about 100 nm or less. The surface is exposed to a plasma and simultaneously illuminated with a pulsed laser beam having a predetermined polarization along the x-direction or the y-direction, and the trenches are etched.