Helium-Oxidizing Plasma Etching Carbon Features
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Solution Overview
Problem
Conventional methods for etching carbon-containing features, such as photoresist lines in semiconductor devices, face challenges in reducing lateral width without preferentially reducing the height, especially when feature sizes approach 40 nanometers, due to limitations in photolithographic techniques and ionized plasma etching.
Innovation Solution
A method involving the generation of a plasma from a gas mixture of helium and an oxidizing gas within a reaction space to anisotropically etch carbon-containing features, enhancing the lateral etch rate while maintaining the height, thereby reducing the critical dimension of the feature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If ionized plasma is used to etch carbon-containing features, then the lateral width is reduced, but the height is preferentially reduced
Solution Approach 1:
The patent changes the physical and chemical parameters of the plasma by using a specific gas mixture (helium and oxidizing gas) and controlling plasma power and pressure, to achieve anisotropic etching that preferentially removes lateral material while preserving vertical height
Solution Approach 2:
The patent uses a composite gas mixture of helium and oxidizing gas to create a plasma with unique properties that enable selective lateral etching. The combination of these gases produces a plasma chemistry that differs from conventional single-gas plasmas, allowing control over etching directionality
2Ease of manufacture
If conventional photolithographic methods are used, then the process is simple and low-cost, but features with critical dimensions less than 40 nanometers cannot be formed
Solution Approach 1:
The patent performs preliminary etching of the carbon-containing features before final patterning, reducing their lateral dimensions in advance. This preliminary action enables subsequent lithographic steps to achieve smaller critical dimensions that would otherwise be impossible with standard photolithography alone
3Manufacturing precision
If electron beam or EUV lithography is used to form features below 40 nanometers, then the critical dimension is achieved, but the process becomes complex and costly
Solution Approach 1:
The patent replaces complex lithographic systems (electron beam or EUV) with a simpler plasma etching approach to achieve the same dimensional reduction. Instead of using sophisticated radiation-based patterning, the invention uses plasma chemistry and physics to directly modify feature dimensions
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 effectively reduces the lateral width of carbon-containing features while minimizing the reduction in height, improving the aspect ratio and line edge roughness, and simplifying the process by eliminating the need for additional high-energy irradiation steps.
Implementation Method 1
generating a plasma within the reaction space from a gas mixture comprising helium gas and the oxidizing gas; and anisotropically etching the carbon-containing feature utilizing the plasma
Implementation Method 2
supplying helium gas and an oxidizing gas to the reaction space; anisotropically etching the carbon-containing feature utilizing the plasma
Data Source
AI summary
Methods for etching a carbon-containing feature are provided. The methods may include: providing a substrate having a carbon-containing feature formed thereon in a reaction space; supplying helium gas and an oxidizing to the reaction space; generating a plasma within the reaction space from a gas mixture comprising helium gas and the oxidizing gas; and anisotropically etching the carbon-containing feature utilizing the plasma to cause lateral etching of the carbon-containing feature.