EUV Resist ALE and Selective Capping for Roughness Control
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Solution Overview
Problem
Extreme Ultraviolet (EUV) lithography faces challenges in reducing roughness and improving etch selectivity of EUV resists, leading to undesirable roughness and insufficient etch selectivity in semiconductor fabrication, particularly at advanced technology nodes like 16 nm and beyond.
Innovation Solution
The method involves descumming, divot filling, and protecting EUV resists by treating the substrate with halogen-containing plasmas, selectively depositing silicon-containing precursors, and forming silicon oxide caps or amorphous carbon caps to enhance etch selectivity and smoothness, using techniques like atomic layer etching and plasma processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EUV lithography is used for patterning at advanced technology nodes, then resolution is improved, but roughness in the photoresist increases due to stochastic effects
Solution Approach 1:
The patent applies preliminary descumming and divot filling actions to the EUV resist before the etching process. By removing scum and filling divots in advance, the resist surface is prepared to reduce roughness and improve etch selectivity, directly addressing the roughness problem while maintaining the high resolution capability of EUV lithography
Solution Approach 2:
The patent introduces an intermediary protective layer deposition step between the EUV resist patterning and the etching process. This protective layer acts as a mediator that smooths the resist surface and enhances etch selectivity, allowing the resist to maintain both high resolution and reduced roughness during subsequent processing
2Measurement precision
If EUV lithography uses certain photoresist materials to achieve 30 nm scale patterning, then resolution is improved, but etch selectivity to the underlying layer becomes insufficient
Solution Approach 1:
The patent applies preliminary protective layer deposition to the EUV resist before etching. This protective layer is deposited in advance to enhance the etch selectivity of the resist to the underlying layer, ensuring that the resist maintains sufficient selectivity while achieving the required 30 nm scale resolution
Solution Approach 2:
The patent creates a composite structure by depositing a protective layer on top of the EUV resist. This composite material system combines the high-resolution patterning capability of the EUV resist with the enhanced etch selectivity provided by the protective layer, resolving the contradiction between resolution and etch selectivity
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 results in smoother features and increased etch selectivity, improving the quality of etched patterns and preventing defects, thereby enhancing the precision and yield of semiconductor fabrication processes.
Implementation Method 1
treating the exposed portion of the metal oxide layer with a halogen-containing plasma
Implementation Method 2
selectively depositing a silicon-containing precursor on carbon-containing features
Implementation Method 3
selectively depositing a silicon-containing precursor
Implementation Method 4
treating the silicon-containing precursor to convert the silicon-containing precursor to a silicon oxide cap
Implementation Method 5
exposing the modified scum on the surface of the patterned EUV resist to a plasma of an inert gas to remove the modified scum
Data Source
AI summary
Provided herein are methods and systems for reducing roughness of an EUV resist and improving etched features. The methods involve descumming an EUV resist, filling divots of the EUV resist, and protecting EUV resists with a cap. The resulting EUV resist has smoother features and increased selectivity to an underlying layer, which improves the quality of etched features. Following etching of the underlying layer, the cap may be removed.