Substrate Drying via Humidity-Controlled Hydrophobization
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Solution Overview
Problem
Existing substrate processing methods face challenges in satisfactorily drying the upper surface of substrates due to issues with pattern collapse caused by high surface tension of rinse liquids and incomplete hydrophobization, leading to either pattern collapse or particle generation from unreacted silylating agents.
Innovation Solution
A substrate processing method that involves supplying a hydrophobic agent, followed by a low surface-tension liquid, and adjusting humidity to prevent polymerization of the hydrophobic agent and reduce water content in the low surface-tension liquid, ensuring appropriate hydrophobization and minimizing particle generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a silylating agent is supplied to hydrophobize the substrate surface, then pattern collapse is prevented, but particles are generated due to polymerization in high humidity
Solution Approach 1:
The patent changes the humidity parameter of the atmosphere during silylating agent supply. By controlling humidity to be 5% or less, the patent prevents polymerization of the silylating agent while maintaining its hydrophobizing effect, thus preventing both pattern collapse and particle generation from polymer precipitation
Solution Approach 2:
The patent creates an inert low-humidity atmosphere environment during the silylating agent supply process. This controlled atmosphere prevents unwanted chemical reactions (polymerization) of the silylating agent, allowing it to function properly for hydrophobization without generating harmful particles
2Object-affected harmful factors
If water content in low surface-tension liquid is reduced, then surface tension is lowered to prevent pattern collapse, but drying efficiency decreases
Solution Approach 1:
The patent changes the water content parameter of the low surface-tension liquid to be 5% or less. This parameter optimization achieves the dual benefit of maintaining low surface tension for pattern protection while preserving sufficient drying efficiency through the organic solvent's evaporative properties
3Object-affected harmful factors
If humidity is increased to prevent silylating agent polymerization, then unreacted agent remains causing particles, but pattern collapse is prevented
Solution Approach 1:
The patent optimizes the humidity parameter to a specific range (5% or less) that prevents silylating agent polymerization. This parameter control ensures complete reaction of the silylating agent with the substrate surface, eliminating unreacted agent that would otherwise form particles while maintaining the hydrophobizing effect
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
The method effectively prevents pattern collapse and particle generation by ensuring thorough hydrophobization and reducing surface tension, allowing for efficient drying of the substrate surface.
Implementation Method 1
an upper surface of the substrate is hydrophobized by a silylating agent (hydrophobic agent) to lower a surface tension applied to a pattern
Implementation Method 2
IPA is supplied to an upper surface of a substrate to replace water entered into an interior of a pattern by IPA and remove IPA thereafter
Implementation Method 3
the amount of water which dissolves into a liquid film of the low surface-tension liquid on the substrate may be increased to raise the surface tension
Implementation Method 4
When the atmosphere in contact with a silylating agent on a substrate is high in humidity, before reactions with an upper surface of the substrate, a polymerization reaction of the silylating agent proceeds and the silylating agent is polymerized
Data Source
AI summary
A substrate processing method includes a substrate holding step of holding a substrate horizontally, a hydrophobic agent supplying step of supplying to an upper surface of the substrate a hydrophobic agent which is a liquid for hydrophobizing the upper surface of the substrate, a low surface-tension liquid supplying step of supplying the low surface-tension liquid to the upper surface of the substrate in order to replace the hydrophobic agent on the substrate by a low surface-tension liquid lower in surface tension than water, and a humidity adjusting step of adjusting humidity of the atmosphere in contact with a liquid film on the substrate such that the humidity of the atmosphere in contact with a liquid film on the substrate in the hydrophobic agent supplying step reaches a first humidity and the humidity of the atmosphere in contact with a liquid film on the substrate in the low surface-tension liquid supplying step reaches a second humidity which is humidity lower than the first humidity.