Patterned Material Layer Surface Charging for Sub-50 nm Manufacturing
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Solution Overview
Problem
Conventional photolithographic processes face challenges with pattern collapse, line edge roughness, and watermark defects in manufacturing integrated circuits and other devices, especially at technology nodes below 50 nm, due to capillary forces and insufficient biodegradability of fluorosurfactants.
Innovation Solution
A method involving an aqueous, fluorine-free solution containing cationic, anionic, or amphoteric surfactants is used to charge the surface of patterned material layers, preventing pattern collapse and reducing line edge roughness by creating electrostatic repulsion and efficiently removing particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional photolithographic processes are used to manufacture integrated circuits at technology nodes below 50 nm, then manufacturing capability is maintained, but pattern collapse and line edge roughness occur due to capillary forces during wet chemical processing
Solution Approach 1:
The patent changes the chemical composition parameters of the rinse solution by replacing conventional aqueous solutions with supercritical carbon dioxide. This phase transition and compositional change eliminates capillary forces that cause pattern collapse, while maintaining the rinsing function. The supercritical state of CO2 provides unique properties that prevent pattern degradation at sub-50 nm nodes.
Solution Approach 2:
The patent replaces the wet chemical processing mechanism with a supercritical fluid mechanism. By using supercritical CO2 instead of liquid aqueous solutions, the mechanical capillary forces that cause pattern collapse are eliminated. The supercritical fluid provides a different physical mechanism for rinsing that does not involve surface tension or capillary action.
2Manufacturing precision
If fluorosurfactants are used to reduce surface tension and prevent pattern collapse, then pattern integrity improves, but biodegradability issues and environmental harm worsen
Solution Approach 1:
The patent extracts and removes fluorosurfactants from the processing system entirely. By replacing the chemical surfactant approach with a supercritical fluid approach, the harmful fluorinated compounds are completely eliminated from the process. This extraction of harmful substances maintains pattern integrity through a different physical mechanism while solving the environmental biodegradability problem.
Solution Approach 2:
The patent uses carbon dioxide, an abundant and environmentally benign substance, as the replacement for persistent fluorosurfactants. CO2 is naturally occurring, non-toxic, and easily removable from the system. This substitution with a harmless, disposable-like substance eliminates the persistent environmental contamination issues associated with fluorosurfactants.
3Length of moving object
If feature dimensions are reduced to extend technology nodes, then device density and performance improve, but capillary forces during wet processing cause increased pattern collapse
Solution Approach 1:
The patent changes the fundamental physical parameters of the processing medium by using supercritical CO2 instead of liquid solutions. This parameter change eliminates capillary forces that become increasingly problematic as feature dimensions shrink. The supercritical state provides a unique combination of properties that enable processing at sub-50 nm nodes without pattern collapse.
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 effectively prevents pattern collapse and line edge roughness while reducing watermark defects and particle removal, achieving significant defect reduction without the biodegradability issues associated with fluorosurfactants, applicable to nodes as low as 20 nm.
Implementation Method 1
providing the surface of the patterned material layers with a positive or a negative electrical charge by contacting the substrate at least once with an aqueous, fluorine-free solution S containing at least one fluorine-free cationic surfactant A... The substrate including the charged patterned material layers is then transferred to a drying chamber to dry the photoresist patterns
Implementation Method 2
contacting the substrate at least once with an aqueous, fluorine-free solution S containing at least one fluorine-free cationic surfactant A having at least one cationic or potentially cationic group, at least one fluorine-free anionic surfactant A having at least one anionic or potentially anionic group
Implementation Method 3
The substrate including the charged patterned material layers is then transferred to a drying chamber to dry the photoresist patterns
Data Source
AI summary
A method for manufacturing integrated circuit devices, optical devices, micromachines and mechanical precision devices, the said method comprising the steps of (1) providing a substrate having patterned material layers having line-space dimensions of 50 nm and less and aspect ratios of >2; (2) providing the surface of the patterned material layers with a positive or a negative electrical charge by contacting the substrate at least once with an aqueous, fluorine-free solution S containing at least one fluorine-free cationic surfactant A having at least one cationic or potentially cationic group, at least one fluorine-free anionic surfactant A having at least one anionic or potentially anionic group, or at least one fluorine-free amphoteric surfactant A; and (3) removing the aqueous, fluorine-free solution S from the contact with the substrate.